ALBERT

Notes: When a small, transparent replica of a seismic section is illuminated by a homogeneous beam of coherent, monochromatic parallel light a diffraction pattern is created that is representation of the double Fourier spectrum of the recorded seismic waves, i.e. their spectrum in terms of frequency, f, and apparent wave number, k.Masking selected parts of this diffraction pattern causes the spectrum to be filtered: the recomposition of the filtered spectrum then provides a filtered section.The ideal seismic section for this purpose would be a continuous variable density section obtained from recording made at every point of the seismic line. The light transmission coefficient (in terms of light amplitude) at each spot of the replica should be linearly related to the instantaneous seismic signal strength at the spot on the seismic section to which it refers.Unfortunately we cannot make recordings at every point of a seismic line and in our practically realisable recordings we have to be content with sampling in the direction of the location coordinate x. This means that with variable density recordings aliasing will be present and evident in the spectrum obtained in the direction of k; furthermore, the aliased spectrum is also multiplied by a sine function of k because the recording obtained at a given station is not presented on the seismic section as a single line along the time axis, but occupies the entire width of the trace.The diffraction patterns created by variable density recordings of dipping sine waves, including clipped recordings, and of the effect of dip filtering in such sections are discussed. The efficiency of dip rejection is shown to decrease with increasing dip.The diffraction pattern of a variable density recording is found to be characterised by a relationship between point pairs in the pattern.No such simple relationship has been found for the diffraction pattern of a variable area section; the spectra of such VAR sections belong to a very special class, because the amplitude transmission coefficient has only two values, viz. 0 and 1.Consequently, selective masking of the diffraction pattern of a VAR section may give rise to a filtered profile that does not look like a VAR section at all.General statements about the diffraction pattern of VAR sections are hard to give, because the transmission coefficient at a given point in the replica is not proportional to the signal level in the seismic section at the relevant point.In the case of VAR presentation of harmonic waves it was found that, as well as the aliasing effect in the k direction, higher harmonics of the frequency are also introduced.Some synthetic examples are given that show dip filtering to be less effective with VAR than with variable density recordings.Some arguments are advanced in favour of the opinion that high-pass filtering of VAR sections will have less success than low-pass filtering. This is demonstrated by two synthetic examples.

Notes: The theory is explained and practical applications are shown for a numerical procedure in seismology. Particularly the problems concerning the generation of waves under the action of external pressures, and their propagation, in non-homogeneous, both elastic and absorbing media, have been carried out. These problems have been assumed mono-dimensional and refer to plane and spherical waves.The procedure is based on the solution, by means of series, of the wave differential equation, non-homogeneous, and with non-constant coefficients. It is a direct numerical method whose advantage is, mainly, the possibility of tackling, without great difficulties, problems regarding non-homogeneous elastic and absorbing media.On the contrary the methods which require the theoretical expression of the solutions by means of formulae, generally, present conceptual and numerical difficulties.As examples of application of this procedure, the following cases have been carried out by means of numerical calculations.a) Propagation of a wave, initially of symmetrical shape, in a viscoelastic medium; from the results it appears that the wave propagates without losing its symmetry, i.e. without sensible dispersion. A theoretical analysis has been carried out to justify this result, showing that the dispersion in viscoelastic media is noticeable only for relatively high frequencies. It seems that the practical absence of dispersion in field experiments do not exclude necessarily the viscoelastic character of absorption.b) Generation of plane waves under the effect of a uniform pressure distributed on the plane surface of a medium. The way the length and the shape of the generated wave depends not only on the type of pressure acting on the surface but also on the near surface impedance variations has been studied.c) Generation of a spherical wave under the action of a pressure in a spherical hole.The examples treated show how the length and shape of the wave depends on the radius of the hole. Particularly the frequencies of the wave spectrum are proportional to this radius, for a given type of pressure acting in the hole.The characteristics of this procedure would also permit the study of media for which the stress-strain relations are not univocal and linear (non linear absorption). This study, interesting for the wave propagation in rocks, is worth while to be carried out in a special paper.

Notes: For the computation of the vertical component Hz of the magnetic field of a horizontal A.C. dipole lying on the earth's surface, a recurrence formula is presented for a horizontally stratified half space, to obtain the (n+ 1)-layer case from the w-layer case.By means of several computed diagrams for the two-layer case, Hz can be determined for different ratios of conductivity of the subsoil and that of the overburden. Thereby the distance from the dipole as well as the layer thickness h are expressed in terms of the wave length A of a plain wave in the overburden. Assuming a sufficiently large conductivity difference, the results show that evidence about the subsurface conditions can be obtained if the distance between the measuring coil and the dipole is of the order of A/3, and if the thickness h of the layer varies within the range A/100 〈 h 〈 A/6.As an example for the 3-layer case, a nonconducting intermediate layer is assumed.

Notes: A nomogram is presented which enables evaluation of the components of magnetic attraction of a homogeneous finite rectangular prism, and of gravitational attraction due to a uniform rectangular lamina.In practice any three-dimensional body could be approximated by a number of right rectangular prisms of varying dimensions governed by the shape of the body. The magnetic attraction of the whole body is then obtained by numerical summation of the effects of the constituent prisms.For evaluating the gravitational effect, the cross-section of the body corresponding to each elevation contour is approximated by a number of rectangular laminae (or by a stepping polygon) the attraction of which can be determined with the aid of the same nomogram. The total gravitational attraction of the body is obtained by a process of graphical integration along the vertical axis.

Notes: In [50] and [51] a theory has been developed relating formation factor, permeability and porosity of porous sedimentary rock by means of statistical parameters of the pore system, and further, tying those statistical parameters to other macroscopically measurable quantities like capillarity, capillary retention, flow dispersion etc. This paper deals with experimental methods and apparatus for checking the theoretically derived relations using columns of packed loose or artificially consolidated sands or other granular matter. Some initial experiments, mainly intended for checking out equipment and methods are reported. The discussion of the results so far shows good agreement with the theory in most cases, except for the irreducible water saturation. However, for a definite statement on the general validity of the theory more data must be accumulated.

Notes: Some of the methods such as regional removal and second derivative calculations which can be used to outline anomalies on potential data maps can be thought of as a filtering operation. The analysis and design of such two-dimensional filters by means of direct and inverse two-dimensional Fourier transforms have been considered.An analysis of several published sets of second derivative coefficient sets indicates that, in general, they are not a good approximation to the theoretical second derivative filter. Alternate methods of designing regional removal and second derivative filters are discussed. The properties of various two-dimensional filters are further illustrated by means of maps obtained from the convolution of several of these filters with a set of observed field data. These maps show the large changes in anomaly shape which can result from the inclusion or rejection of various wavelength components.

Notes: Integration of the continuous seismic reflection profiler with the marine refraction method on engineering surveys offers a solution to hidden layer problems, allowing both layer velocity and thickness to be computed.

Notes: This paper is the follow-up of an earlier paper by the same author on the calculation of standard-graphs for horizontally stratified subsoils. The method which was developed in that earlier paper was destined for handwork; it was laid down in master-tables. The present paper deals with the presentation of similar methods to the computer expert in purely mathematical denotation. Two different denotations are described for the calculation of the image pole strengths involved. The first denotation is an improved version of Watsons formulae; it gives the total strengths. The second denotation preserves the character of successive approximations as described in the previous paper. Both denotations have been worked out until a six layer resistivity profile, but actually there is no limitation to the number of layers. There is no restriction to the resistivities of any layer. The only condition is now that all interface depths must be integers.This paper is followed by a paper on the relevant computer program by Argelo in this same issue

Notes: Book review in this articleJ. Frihagen, Electron Density Profiles in Ionosphere and Exosphere, North-Holland Publishing Company, Amsterdam, 1966, price N. fls. 60,–.J. A. E. Allum, Photogeology and Regional Mapping, Pergamon Press, London, 1966, 107 pages, 16 plates, 23 figures, price 17 s 6 d net.

Notes: The voluntary intake by penned sheep, of two Rhodes-grass varieties (Samford and Callide) cut at 4 stages of maturity was studied. Intake of dry matter was correlated with in vitro digestion of DM after 12 h incubation. The intake of digestible DM was correlated (r=0.99) with the sum of the digestion after 12 and 48 h incubation.Coarsely ground samples (2.5 mm screen) were digested in vitro less rapidly than finely ground samples (0.4 mm screen), especially with the more mature forages. DM digestibility, voluntary intake of DM and digestible DM were also correlated (r〉0.96) with faecal nitrogen, although different regression equations applied to the two varieties.

Notes: The effect of irrigation on the weight of roots and on the vertical distribution of roots by weight in the soil profile under grass and grass/clover swards was examined in several field experiments.The weight of root material was less under irrigated swards than under those which were subject only to natural rainfall; it is postulated that this occurred because dead roots decayed more rapidly in the irrigated swards. There was little evidence to suggest that irrigation had any major effect on the vertical distribution by weight of roots within the soil profile.There was a significant interaction between nitrogen and irrigation; in the un-irrigated swards, root weight decreased with increased N but on the irrigated swards the highest root weight was at an intermediate level of applied N.

Notes: S23 and S24 Lolium perenne and S37 and S143 Dactylis glomerata were cut to heights of 1 1/2 and 4 1/2 in. in a replicated experiment, using: a flail harvester, a reciprocating mower, and a reciprocating mower followed by a flail harvester to collect the wilted grass.At the short cutting height there was a marked depression of regrowth of all grasses following the use of the flail harvester (P〈0.01), compared with the other mowing treatments. No such effect was observed at the higher level of cutting. Close cutting with a flail forage harvester was shown to be detrimental to regrowth, but the reasons for this effect are not clear.

Notes: Timothy and bromegrass were studied in pure sowings in a glasshouse, and each in a mixture with lucerne, dominated by the grass–fraction in the first crop year, in the field. In the glasshouse both species were cut 3, 5, or 6 times at a 2–in. and 6 times at a 3/4–in. stubble height. In timothy, cutting 6 times gave lower DM but higher protein yields than less frequent cutting. In bromegrass close cutting gave higher DM yields than lax cutting. The following results applied to both species: root weight decreased with increasing severity of defoliation, final tiller density was very low under close cutting, and a complete application of N at the time of sowing was superior to a split application.In the field, the first cut was taken on 5 dates at intervals of 1 week, the second cut 6 or 8 weeks after the first cut, and the third cut 7 weeks after the second cut (for bromegrass mixture only). DM yield was generally the higher the later the first cut was taken and the longer the subsequent rest period. However, the opposite applied for best sustainment of yield. The 1 1/2–in. stubble treatments outyielded the 3 1/2–in. treatments. Generally, production of CP was influenced more by DM yield than by % content. Reduced removal of tiller primordia in the second cut led to higher third–cut yields, but at the cost of total yield. Difficulties in the control of shoot apex removal encountered in both glasshouse and field are discussed.

Notes: Over 13 years, 12 cwt/ac of ground rock phosphate (29% P2O5) were applied to an old grass sward, either completely in the first year or in equal amounts in each of the first 4 years; alternatively, 18 cwt superphosphate/ac were applied either in 3 equal amounts at 4–yearly intervals, or in equal amounts annually over the first 12 years.In the first year, the larger dressing of superphosphate gave the best response, measured as fresh herbage cut in mid–July each year, but during the next 7 years all methods of application gave similar yields. Dressings of rock phosphate gave progressively poorer response after 7 years and plots so treated were not significantly better than the control in the final year. At the end of the experiment, plots receiving annual applications of superphosphate yielded most herbage and those which had received superphosphate at 4–yearly intervals still showed a significant response. Phosphate in rock phosphate applied as a single dressing was two–thirds as effective over an 8–year period as that in superphosphate applied annually.The small difference over 12 years in phosphate uptake from 3 dressings of superphosphate compared with its equivalent in annual applications suggested that little phosphate fixation was taking place. The fact that a single dressing of rock phosphate was able to maintain yields and phosphate uptake close to that obtained from annual applications over 7 years supports this and suggests that the failure to utilize one third of the phosphate in rock phosphate was mostly due to initial insolubility.

Notes: Seven species or varieties of grass, and a mixture of 3 of them, were sown in pure swards, treated with 4 levels of nitro-chalk (0, 17·5, 35, and 70 Ib N/ac/cut) and cut 4 or 5 times each year. Each species and the mixture were also sown with white clover, and the effect of fertilizer N on the yield of N in each grass was compared with the effect of clover on the yield of N harvested from the grass/clover swards.The regression line for response in yield of N with increasing levels of fertilizer N showed slight, but significant, upward curvature. The grasses differed in their uptake of N from the soil, S37 cocksfoot and S48 timothy showing relatively high uptakes, and the ability of each grass to take up fertilizer N was usually related to its uptake of N from the soil. Differences in the yield of dry matter between the species, at a similar level of N, are discussed, and it was concluded that perennial ryegrasses were most efficient and Agrostis tenuis was least efficient in using the N taken up in the production of DM.In general, there were no significant differences between the yields of N of the grass/clover mixtures; the N yields of the grass components were significantly different and tended to be inversely related to the N yields of clover.Grasses which gave high yields of N with fertilizer were also high yielding when grown in association with clover. Pure grass swards required more than 200 Ib fertilizer N/ac/yr in order to yield the same amount of N as the grass/clover swards. The amount of N estimated to have been derived by grass from clover (indirect effect of clover) increased each year; it was highest with S37 cocksfoot and lowest with Irish perennial ryegrass, averaging 46 and 23 Ib N/ac/yr, respectively.

Notes: The herbage and associated habitat factors of 15- to 20-years-old reclaimed hill pastures were investigated in Mid–Wales. These swards had been reclaimed from natural hill vegetations by ploughing and sowing. The results were examined to determine which habitat factors were associated with sward reversion. Particular emphasis was given to determining how far reversion was under the control of the farmer. On ill-drained soils the swards became heavily infested with Juncus effusus, regardless of management. On well-drained soils reversion was largely prevented by maintaining an adequate stocking rate in summer, coupled with periodic applications of lime and basic slag. Inherent podsols required approximately twice as much lime as inherent brown earths for the equivalent maintenance of soil pH and sward composition.

Notes: Sowing pasture species with wheat caused a reduction in the growth and yield of the pasture species. This reduction was more severe with wheat drilled at 7 inch row spacing than at 14 in., and was least when the two crops were in alternate 7 in. rows. The reduction appeared to be due principally to the shade cast by the wheat. The pasture also reduced the growth and yield of wheat, but the effect of row spacing and position were opposite to and very much less marked than those of wheat on pasture. The yield of the pasture early in the following season was related to the seed yields in the year of establishment; later in the season, however, differences in yield among the various treatments disappeared.

Notes: The degree of precision obtained In the quality testing of grass varieties under two systems of management was examined (1) in a single cut, (2) under a system of proportionate bulking of produce from individual cuts during a season, and (3) after pooling two seasons’ data from two centres.Crude protein, crude fibre, soluble carbohydrate, and in vitro digestible dry matter were determined. The components of variance were analysed and in the data from single cuts varietal differences in digestibility of 2.10 were significant (P=0.05). Using data from two seasons at two centres, a high degree of precision was obtained for all attributes in a grazing management system and varietal differences in digestibility of 1.25% were significant.Variation due to location and season was greater in hay cuts taken 10 days after ear emergence. In both systems varieties differed more in soluble carbohydrate content than in the other chemical components.

Notes: The use of the correct variety has an important influence on the economic use of sown grassland. The production of seed must be done in such a way that the essential characters of varieties are preserved. The O.E.C.D. Herbage Seed Scheme provides a sound basis for seed production, and has made possible the wider exploitation of good seed growing areas. The technical basis for some of the rules is discussed. It is concluded that in the 8 years in which the Scheme has been operating there has been a significant change in the pattern of seed use with a greater emphasis on the better varieties.

Notes: Book reviewed in this article:NIX, J. Farm management pocketbook.COOKE, G. W. The control of soil fertility.MOORE, L Grass and grasslands.SHIRLAW, D. W. G. An agricultural geography of Great Britain.LEOPOLD, A. C. Plant growth and development.LARIN, L V. [Ed.] Advances in pasture and hay-meadow management.

Notes: Experiments with cows and sheep are described in which the voluntary intakes of hay and silage of differing digestibility were determined. The voluntary intake of hay increased consistently with increasing digestibility, but the relationship was not as well defined for silage. The addition of concentrates depressed the intake of hay, and this effect was more marked for hay with a high digestibility than with poorer quality hay. Concentrates appeared to depress the intake of hay by sheep more than by cows, an effect which was again more marked when the hay had a high digestibility value.

Notes: The responses of Phalaris tuberosa L. to cutting to 1/2- and to 3-in. at 3 levels of nitrogen (0, 23 and 92 lb/ac after each cut) were investigated in two irrigated, small-plot trials. A technique involving the use of sheet-iron borders embedded in the soil to contain root systems, irrigation water and fertilizer was developed. The 3-in. cutting height gave greater dry-matter yields than J in., the difference reaching significance only with applied N. Plant mortality was significantly greater for the 1/2-in. cutting height at each N level. N significantly increased DM yield at both cutting heights, the greatest yield being at the higher application rate. Plant mortality at both cutting heights was significantly reduced by applied N. The results are discussed in relation to the most suitable grazing management for sustained growth of irrigated Phalaris swards.

Notes: High precision gravity surveys have to be examined at different points of view: the accuracy which one can expect on the final results, regardless to their distribution, the shape and amplitude of the expected anomalies, depending on these factors, which grid of stations is convenient in each particular case.Under certain condition, using an appropriate procedure, involving strict criteria, it is possible to get on the Bouguer map the same accuracy as the reading one.However an accuracy closed to 0,01 mgal does not imply that anomalies as 0,01 or 0,02 mgal deserved attention. Numerous factors limit our appreciation of significant anomalies to 0,05 mgal, may be a little less.When cavites are concerned, it is always necessary to define the extreme dimensions an depth of volumes which may give detectable anomalies.Some example are given illustrating different aspects of this particular type of geophysical prospecting.

Notes: Several papers presented at the last SEG Convention in Houston by Schneider, Backus et al have shown how important and fruitful it was to obtain a continuous knowledge of the velocity functions and they have solved their problem by a Dynamic Correlation Analysis. Our purpose is to introduce here a method based on the best summation of a set of traces instead of the best correlation.Practically, this approach has several advantages:1) Two traces only can be correlated at each step whereas the summation can bear on any number of them;2) Optimizing the summation is actually what we are looking for since, at the long end, the success of the improvement is evaluated from the compositing of several traces either weighted or not.On the other hand, an advantage of correlation is the possibility of adding correlations obtained at several places in a same neighbourhood in order to improve the results. With the summation method this is feasible only when dips are inexistent: we shall see that the difficulty due to the dip effect can be turned around.The basic principle of the method can be summed up as follows: traces relating to a same reflection point are considered; several composites are made, each after applying different move out corrections ranging widely around an estimated adequate velocity function. At each time coordinate, the best adapted velocity function, i.e. the one that yields the best phase relation between reflected events, corresponds to the composite trace the average amplitude of which is the largest.This way, the velocity function corresponding to primary reflections as well as those corresponding to multiple reflections can be established accurately.Some examples are shown.

Notes: The problem of elastic waves–from point sources–in layered media is solved in a general and elementary way. Only the simplest principles of the Theory of Functions are necessary. The solutions can immediately be used for numerical applications.

Notes: The symmetry shown, by the function describing the magnetic anomaly due to a dyke or vertical fault step leads to a method by which an observed profile may be adjusted to conform with that symmetry. By making these adjustments a minimum the ideal dyke or fault profile closest to the observations is constructed. In three of four possible situations this is interpreted by simple geometry.Parallelpiped models may be transformed into two dykes for symmetry analysis. Depth limited models are not so amenable, even in special cases.

Notes: The use of digital recorders and computers in seismic exploration promises major enhancement of the quality of final documents available to interpreters. The ultimate objectives of recording and processing remain what they always have been:1 Record the reflection wavelet as a function of time; this requirement has been met with satisfactory accuracy for a number of years.2. Record the reflection wavelets with sufficient fidelity to permit the interpreter to recognize them.Various factors affect our ability to achieve this second objective. Certain recording errors are associated with digital recording systems. However, an understanding of the sources of error will enable the operator to use his system properly and to estimate the noise level or inaccuracy of field recordings. Field operations do not require rigorous error analysis; in most cases a satisfactory approximation can be obtained from simple calculations.Three types of “noise”–seismic, instrument and power line–introduce errors. Factors which contribute to over-al recording system error include specifically input noise, power supply ripple, crosstalk, A-D conversion error, quantizing noise, aliasing, distortion. Examination of each component of a recording system, permits the determination of its ultimate effect on the over-all noise level–or error level–of the entire system.Many of the error sources produce statistically independent noise which is not correlative. Where this is true, error voltages from various sources may be combined by taking the square root of the sum of the mean square noise voltages, giving a result slightly greater than the largest single voltage if one source is much greater than any other source. This simplification can be used to estimate over-all system noise levels. Distortion and crosstalk depend on signal amplitude and should be added algebraically in each category. Each final sum should be used as a statistically independent noise source with respect to other system noise sources.Using the foregoing examples and simplified system for estimating over-all system noise, and assuming that much of the distortion (which limits signal/instrument noise ratio to 54 db) can be removed by filtering, we determine that the combined effect of all sources of error is to reduce the system S/N ratio to approximately 74 db.With proper care digital field recording systems can produce very good field records, and exotic computer processes can enhance signal and reduce various forms of noise. However, one always must recall that the level of confidence which one can place in an interpretation of seismic data must be dependent on a knowledge of the accuracy of the basic data.

Notes: The Terrapak is a new seismic energy source of the surface energy source type. Essentially, the Terrapak consists of a compressed air piston which transmits a shock to the ground by means of a striker plate attached to the piston rod. The Terrapak is truck-mounted together with its ancillary equipment. Shocks can be generated at 8 second intervals, and although the weight of the striker is relatively low (approximately 1400 Ibs) the impact velocity exceeds 66 ft/sec. The energy available is about 85,000 ft. lb., which is equivalent to that produced by conventional weight-dropping methods. The power spectrum of the seismic wave produced by the Terrapak is spread out towards the higher frequencies because its impact velocity is greater than that of a dropping weight.There is a noticeable difference between noise records made with the Terrapak and noise records made with a conventional weight-dropping technique. The same noise frequencies are found in both cases, but low frequency noise is stronger with weight dropping than with the Terrapak, whereas the intermediate frequency reflections obtained using the Terrapak are more suitable for correlation.The expansion of the compressed air generates a sound wave, the effects of which must be eliminated by the use of multiple geophone arrays. A spectrum analysis of the records has confirmed that the waves produced by the Terrapak are rich in intermediate frequency components. This facilitates the picking of reflections in normal areas where the apparent frequency of the reflections is about 30 to 35 c/s.

Notes: This paper includes publication of two algorithms, to be processed on a digital computer. The algorithms are based upon the two mathematical denotations, presented by Dr. J. C. van Dam in this same issue. The computer programs are written in Algol, in the form of procedures (i.e. subroutines to be activated from a surrounding Algol program).Each of the two procedures is preceded by a numerical analysis. Some remarks are made about the reliability of each of the two procedures, the production and the computing time required.

Notes: The theory of statistical communication provides an invaluable framework within which it is possible to formulate design criteria and actually obtain solutions for digital filters. These are then applicable in a wide range of geophysical problems. The basic model for the filtering process considered here consists of an input signal, a desired output signal, and an actual output signal. If one minimizes the energy or power existing in the difference between desired and actual filter outputs, it becomes possible to solve for the so-called optimum, or least squares filter, commonly known as the “Wiener” filter. In this paper we derive from basic principles the theory leading to such filters. The analysis is carried out in the time domain in discrete form. We propose a model of a seismic trace in terms of a statistical communication system. This model trace is the sum of a signal time series plus a noise time series. If we assume that estimates of the signal shape and of the noise autocorrelation are available, we may calculate Wiener filters which will attenuate the noise and sharpen the signal. The net result of these operations can then in general be expected to increase seismic resolution. We show a few numerical examples to illustrate the model's applicability to situations one might find in practice.

Notes: In order to adequately understand the complicated, anelastic processes governing wave propagation in soils or highly weathered rock it seems desirable first to have available a convenient laboratory material for such propagation studies the frequency dependent rheological parameters of which are known beforehand. A property measurement program has been conducted to determine the complex Young's modulus and the complex shear modulus of a commercially available viscoelastic material over a broad spectral region.

Notes: In the year 1958 the Service for Water Management of the „Rijkswaterstaat” started its program of geo-electrical resistivity prospecting in the western part of the Netherlands. The aim of this program was to obtain data on the salinity distribution of the ground water.The ground water regime in this part of the Netherlands is most intricate. This is due to the geological and geo-hydrological conditions and to the low elevation of the land. Many reclaimed areas are up to several metres below mean sea level.The resistivity data obtained are closely related to the salinity of the ground water. On the basis of bore hole data it was even possible to arrive at calibration curves for the salinity of the ground water in sand deposits. Under special conditions it was also possible to draw conclusions with respect to the presence of less permeable formations as e.g. clay layers.Some remarks are given on the practical performance and the interpretation of the measurements.A review is given of the work done until now. Some results are shown by means of maps of the salinity distribution of the ground water in the western and northern parts of the Netherlands.Two examples are described of the use of the data obtained during the survey in the province of Zuid-Holland.Another two examples are presented of detailed investigations for special purposes in relatively small areas.

Notes: In mountainous areas it is an inadequate procedure to reduce gravity observations by merely subtracting the effect of an infinite flat slab of material between the station and sea-level, and adding a terrain correction. A programme is described which directly computes the effect of masses above sea-level, and mass-deficiencies below it; as well as the effect of compensating masses under the Pratt and Airy isostatic systems. As an example, the method has been applied to a regional gravity survey of Papua and New Guinea where it is seen to remove the usually high correlation of the Bouguer anomaly with local topography.

Notes: Bermuda-grass varieties, cut at weekly intervals, differed in salt tolerance when grown in 20 m. eq./l. Hoagland's Solution No. 1 plus 0, 80, 160, 240, and 320. m. eq./l. sodium and calcium chlorides. Weights of above-ground parts decreased while root weight to top weight ratios increased with increased salinity. Highest root weights were obtained at the intermediate to high salt levels.Explanations proposed for the root-growth stimulation are: maintenance of a high photosynthetic rate despite retardation of top growth, reduced percentage defoliation resulting from top growth retardation or a differential response of tops and roots to growth hormones.

Notes: Changes in the cover of three grasses and two clovers sown in ploughed downland were measured annually for 8 years. Perennial ryegrass and cocksfoot were the most persistent of the sown species. Wild white clover increased in the first 3 years, but then decreased considerably, probably as a result of heavy grazing in the spring of 1960, and subsequently never recovered.Invasion by weed species and the rate of reversion of sown leys on the chalk to permanent downland is discussed.

Notes: Book reviewed in this article:WHYTE, R. O. Milk production in developing countries.RICOU, G. [Study of biocoenosis of a “natural” environment: the grazed permanent grassland.]KIRCHGESSNER, M.; FRIESECKE, H. and KOCH, G. Nutrition and the composition of milk.NORTH, P. M. Poisonous plants and fungi in colour.

Notes: Three trials were conducted to compare liquefied ammonia and ammonium nitrate as nitrogenous fertilizers for grassland. One was at Jealott's Hill and the other two at Henley Manor, Crewkerne, Somerset. At neither centre was the response to liquefied ammonia as great as that from equivalent rates of ammonium nitrate applied in a number of split dressings throughout the season.Split applications of liquefied ammonia were more efficient than single large dressings, but even these were not as efficient as ammonium nitrate.The response from a single large application of liquefied ammonia in spring was superior to that from an autumn application, especially under the high-rainfall conditions at Henley Manor.The pattern of response from split applications of ammonium nitrate was more uniform than that from a single application of liquefied ammonia. In general, the latter gave a large mid-summer cut, but fell away badly at the end of the season. These data confirm earlier findings, which also showed that liquefied ammonia was not as efficient as ammonium nitrate applied in the normal way as a nitrogenous fertilizer for grass.

Notes: In a 3 × 3 factorial experiment, the effects of three levels of nitrogenous fertilizer (0, 336 and 672 kg/N per ha) and three grazing intensities on live-weight gains and carcass attributes were measured.The live-weight gains of the animals (per head) over the season were greater at the low and moderate grazing intensities than at the high; this effect occurred mainly from July to October each year. Gains were low on the no-nitrogen swards from July 1962 to the end of the grazing season and throughout 1963: this was related to the very high clover content of the swards.In all years, as grazing intensities increased, the carcass weights per animal became lower. Carcass balance, carcass length, depth of longissimus dorsi muscle, fat thickness over the longissimus dorsi, weight of kidney suet and channel fat, and weight of the alimentary tract also reflected the effect of treatment on weight gains.The results are discussed in relation to the botanical composition and consumption of the herbage, presented in Part I.

Notes: A method is described by which the root systems of herbage species may be separated under field conditions, using a double layer of 500-gauge black polythene. The effect of such a treatment was examined in field trials; tests on the permeability of this material in laboratory and field were also made. Visual, manual and mechanical examinations of the polythene after 2, 3 and 4 years in the soil are reported. From the results obtained it is concluded that polythene used in this manner is not detrimental to either herbage yield or quality, and that it can be expected to remain a satisfactory barrier below ground for at least 4 years. However, the introduction of polythene placed parallel to drilled perennial ryegrass and white clover did reduce total root weight by 20%, with a concomitant loss in yield; this loss was mainly associated with the grass component.

Notes: Book reviewed in this article:LEIGH, J, H. and MULHAM, W. E. Pastoral plants of the Riverine Plain.ANDREEV, N. G. Lugovodstvo. [Grassland management.]HILLS, E. S. (Ed.) Arid lands, a geographical appraisalMCDONALD, P.; EDWARDS, R. A.; GREEN HALGH, J. F.D. Animal Nutrition Edinburgh

Notes: The treatments in this summer–grazing experiment were designed as a 3X3 factorial; 3 levels of nitrogenous fertilizer, supplying 0, 336 and 672 kg N/ha per annum, and 3 stocking rates. The fertilizer was applied in 6 to 8 dressings at intervals of 3 to 4 weeks. The animals used were fattening Hereford X Friesian steers. The stocking rates were calculated on the basis of data available on herbage production under N and irrigation treatments and varied according to the level of N input. The experiment was laid out in 6 randomized blocks, which were grazed in rotation. Blocks were removed from the grazing cycle in spring and early summer of each of the 3 years (1962—-4) over which the experiment was conducted and cut for conservation: yields were recorded. Details are given of: grazing management; results of studies of soil–N levels; the quantities of herbage removed for conservation: the quantity, chemical and botanical composition of the herbage available for grazing; and herbage consumption.

Notes: A conservation experiment is described in which arachis oil was used to improve the energy content of heavily-wilted herbage of approximately 46% dry matter. The 2 oil-treated herbages and 2 control silages were enclosed in polythene film. The DM losses from all 4 silos were high compared with losses normally encountered in completely sealed silos. This is attributed to secondary fermentation which occurred after the silos were opened. The oil had a depressing effect on the digestibility of the mineral matter of both grass and silage. The metabolizable energy values of the silages are reported and discussed.

Notes: A shallow, wide spread perching layer was isolated in the alluvial profiles of western Fresno County, California. Geologic and hydrologic interpretations are given, based on field and laboratory measurements of the physical properties of this layer. Some of the approaches investigated included using existing electrical logs from irrigation wells, head loss observations in wells and piezometers, core drilling, and core analysis. Differences in alluvial profile permeabilities are shown which result in perched water under the existing field flow conditions. The quantity of vertical flow through the layer is estimated using core permeabilities and hydraulic gradients observed in the field.Hydraulic properties and descriptions for the perched zone are presened which can be used to delineate profile flow limitations at other locations in the San Joaquin Valley. The study may be used in estimating the rate at which this perched water table could rise If, in the future, imported water and changes in irrigation patterns cause a large quantity of water to flow vertically.

Notes: The most commonly practiced method of artificial recharge at present is through basins. This spreading method may not be physically feasible or practicable if land values are high or a shallow, densely compacted layer forms a barrier impeding the direct downward percolation of the ponded surface water.For the case of the latter condition, alternative methods of wells or trenches dug down to the pervious aquifer and backfilled with gravel have been investigated. These were explored from the standpoint of construction and operating cost and hydraulic efficiency as influenced by such factors as the depth to the aquifer, the thickness, depth of saturation, permeability and specific yield of the aquifer, interference of closely spaced wells and duration of continuous operation of the wells or trenches. Furthermore, effects of bacterial growth and chemical composition of the recharge water on the hydraulic performance of wells or trenches are discussed.An economic comparison based on field conditions in a prospective recharge site at Stockton, California, is used to illustrate the developed criteria for relative effectiveness of the two methods.As a general conclusion, it was found that while recharge through trenches would be more efficient hydraulically and economically for the case of very shallow subsurface barriers, wells would become more competitive as the thickness of an impervious top layer increases.

Notes: The horizontal viscous flow model with “infinite” areal extent can be used for almost any well flow problem whether two-dimensional or three-dimensional, steady or nonsteady, single aquifer or multiaquifer. This model can also be used in the field of soil mechanics for subsurface drainage problems. The design includes scale model analysis and the application of conformal mapping techniques in order to simulate an ideal aquifer. Construction, calibration, and test procedures for the model are described. The apparatus has proved to be both a valuable research tool and an excellent teaching aid.

Notes: One of the deepest water-exploration wells in the southeastern United States was completed in 1966 at Jacksonville, Florida. It was drilled to a depth of nearly 2,500 feet to supply geologic and hydrologic information on the deeper unexplored part of the Floridan aquifer. This aquifer consists of a series of water producing zones separated by nonproducing zones. An important new fresh-water producing zone was found, and the contact between the fresh water and salt water was located. The well was completed in three separate zones so that it could be used to monitor the the deeper part of the aquifer to detect any salt-water encroachment. This paper describes the objectives, techniques, and results of drilling the test well.

Notes: A rapid graphical technique for the determination of aquifer transmissibility from a variable discharge pumping test is presented. The data required include the variation of discharge with time during the pumping test and a record of the recovery ar an observation well after the well was shut off. An example using a synthetic well data is provided.

Notes: Comparison of the analysis of 3 and 4 day pumping tests with the analysis of water-level changes due to 18 years of pumping suggests that experience in an area can be a critical factor in determining the transmissivity and storativity of an aquifer.

Notes: The rapidly increasing development of ground-water resources in northeastern Illinois has brought about regional and local problems of water supply, thus creating considerable interest in the feasibility of artificial recharge as a partial solution. Artificial ground-water recharge is considered as a partial solution to regional and local problems of water supply in the primarily metropolitan region of northeastern Illinois. Five artificial recharge facilities are now in operation in the area; their average annual recharge rates range from 25,000 to 395,000 gallons per day (gpd). Several additional areas where artificial recharge may be feasible are identified on the basis of criteria established for the region.An initial study in the Park Forest-Chicago Heights area indicates that recharge to the Silurian dolomite aquifer, the source of water supply in the area, is feasible. This study provides guidelines to aid in additional studies of artificial recharge in northeastern Illinois.

Notes: Two case histories are presented which illustrate that by analyzing drill cuttings or bailed samples, by knowing total depth of a test hole and position of the static water level, and by studying the driller's log, not only can a well's yield be predicted—but also drawdown may be predicted for any well in advance of a pumping test.The estimation of specific capacity (gpm/ft of drawdown) is invaluable in well design, particularly in the United States, where drilling contractors work rapidly and efficiently. Knowledge of probable specific capacity can aid in recommending proper screen length, diameter, slot width, and setting. It will enable cost estimates for proper pump size to be made, for casing requirements to be determined, and also for ultimate well diameter and depth to be determined. Test-pump setting can also be anticipated.Case History No. 1 illustrates the above techniques, and how a new well was drilled, developed, designed, and completed adjacent to a poorly designed and equipped water well. The new well proved to be nine times more efficient (i. e., “better”) than the old well. Reasons for this improvement are shown, and the two wells are compared and contrasted.Case History No. 2 shows data from a constant-rate pumping test following calculation of a well's specific capacity using estimates of aquifer permeability. Analysis of dynamic water-level recovery measurements resulted in a transmissibility of 16,150 gpd/ft compared to an estimated 16,000 gpd/ft from a visual inspection of sand analysis grading curves. The well's specific capacity was estimated to be between 8.4 and 8.9 gpm/ft of drawdown. The measured specific capacity was 8.35 gpm/ft with an efficiency of 85 percent. Actual permeability was 230 gpd/ft compared to the estimated 228 gpd/ft2!Six figures are included showing well construction details, sieve analysis curves, a semi-log plot of recovery measurements obtained during an aquifer pumping test, and graphic representations of approximate permeabilities for granular materials ranging from clay/silt to fine gravel. Six tables give characteristics of samples recovered from two test wells, permeability estimates of the disturbed samples, approximate permeabilities of various granular materials, and specific capacities for 100 percent effective water wells with varying diameters, coefficients of storage, and pumping periods. Three photographs further illustrate the principles enumerated.The methods described can give acceptable results (although they may not be as spectacular as the two detailed case histories) if sound judgement is used; if local conditions are somewhat known; if sampling methods are described; and if the procedures are not abused by expecting extreme accuracy. A reasonable estimate, or perhaps, just a close scientific “guesstimate” is all that should be hoped for by the hydrogeologist and his client in predicting well yields. But these techniques are a great advance over the“forked peach stick” philosophy still used for similar purposes by pseudo-scientists in the United States and foreign countries (although no cases where a dowser or “water witch” has successfully predicted drawdown in addition to yield have come to the attention of the writer).The data in this report are derived from approximately 500 wells or more designed by the author in 26 States and in many locations abroad. Rather good success has been obtained regarding close correlation between estimated and measured specific capacities from a variety of geologic environments and aquifer parameters.

Notes: The intensively irrigated Arkansas River Valley in Colorado is underlain by a valley-fill aquifer resting in a U-shaped trough cut in relatively impermeable Cretaceous rocks. Ground water is pumped to supplement surface water; in the last 10 years pumping has more than doubled. Ground water is closely related to the Arkansas River; percolation from irrigation recharges the aquifer, which discharges into the river. Pumping has resulted in a reduction in streamflow because it intercepts water that ordinarily would have reached the river. The 1,500 irrigation wells in the Arkansas Valley withdrew 230,000 acre-feet of water in 1964.An analog model is being used to evaluate the relation of ground water to surface water and to predict effects of changes in water management. The model, simulating a 150-mile reach of the Arkansas Valley (Pueblo to the State line), has a resistor spacing of 8 per modeled mile. The framework for the model was a transmissibility map; transmissibility ranges from less than 50,000 to 700,000 gallons per day per foot. Specific yield averages about 0.2. Hydrologic boundaries, such as the Arkansas River, and the bedrock valley-fill contact were simulated. Applied water, precipitation, evapotranspiration, and ground-water pumping were the independent variables programed. The model is being verified by comparing predicted changes in water level and river discharge with observed changes.

Notes: A method is presented for computing maximum drawdown in a well being pumped intermittently but in accordance with a regular sequence of fixed periods of pumping at constant discharge followed by fixed periods of rest. The method is extended to allow for interruption of the basic pattern by occasional changes such as the elimination of the pumping phase from certain individual cycles.

Notes: SUMMARY— Protein solubility and associated properties were studied in bovine sternomandibularis muscle allowed to pass into rigor in three physical states. Thirty min post-mortem, samples were incubated at 7°C for 48 hr in one of the following conditions: minced through 1/8-in. plate, free to shorten in a vertical position, stretched to 150% of equilibrium length. Stretched muscle exhibited greater protein solubility, higher pH values and longer sarcomeres than the remaining samples. For post-rigor muscle, protein solubility may be related to sarcomere length and moisture press ratio. Variations in sarcomere length may be related to post-mortem changes in pH. Possible relationships between the contractile state of proteins and the chemical, physical and quality characteristics of muscle are discussed.

Notes: SUMMARY— A statistical method, preferably operated by a a computer, is proposed for the analysis of data on complex mixtures where the information sought involves a number of small changes in chemical composition, each of which is individually within the normal range of variation of the mixtures. When the method is applied to the identification of geographical origins of peppermint oils and mixtures of peppermint oils, the results are a substantial improvement on those from previous methods, though still leaving some uncertainty. It is expected that more complete chemical analysis will greatly improve the confidence level.

Notes: SUMMARY— It is known that even small concentrations of sodium chloride cause a loss in the solubility of actomyosin in fillets of Baltic herring. This change is prevented by the simultaneous presence of a sufficient amount of phosphates. To date, the mode of action of phosphates is unsettled. This problem has here been studied by the aid of radioactive pyrophosphate.The fillets were kept in solutions containing sodium chloride, pyrophosphate, or both, at +4°C. The migration of tracer pyrophosphate was followed by application of the auto-radiographic method; at the same time, changes in the solubility of actomyosin were checked. To avoid losses of soluble compounds, the sections for autoradiogaphy were prepared by freeze-drying and paraffin impregnation techniques. It was found that the migration was very rapid: in 24 hr the fillets were completely marked. The rate of migration was also estimated by counting of the sections.Studies were also made of the changes in the phosphorus fractions of the fillets during the course of standing using 1% pyrophosphate and maximal standing time of 5 days. Initially, there occurred a rapid loss of phosphorus compounds from the fillets; this related to the lipid and nucleic acid phosphorus. The tracer migrated rapidly into the fillets during the first day, and more slowly after this. The bulk of the tracer was in the acid-soluble fraction. Apparently, there also occurred some incorporation into the lipids and nucleic acids.

Notes: SUMMARY— Orange essence was stripped from freshly reamed California Valencia orange juice and concentrated to about 150-fold by the Western Utilization Research vacuum-aroma-column (WURVAC) method. The organic volatiles were extracted from the aqueous essence with ether and analyzed by combined gas-liquid chromatography and mass spectrometry. Chromatograms indicated the presence of more than 100 constituents; 39 of these were identified. Compounds previously unreported as orange volatiles are I-penten-3-01, methyl butyrate, methyl hexanoate, benzaldehyde, and γ-decanolactone.

Notes: SUMMARY— Kent mango fruit irradiated with 0, 100, 200, and 300 Krad were ripened at 20°C for 0, 4, and 8 days.Irradiated mangoes were less firm than control fruit immediately after irradiation, but fruit softening due to ripeness was more pronounced than softening induced by irradiation. Irradiated fruit contained higher water-soluble and lower Versene-vinsoluble pectic fractions as compared to unirradiated fruit. NO differences were observed in the content of the Versene-soluble fraction among all irradiation dosages. Higher PE activities were exhibited by the irradiated fruit throughout the ripening period. Irradiated fruit contained higher AIS and lower soluble solids than control fruit. No differences in sucrose content due to irradiation were observed, but there were less reducing and total sugars at the 300 Krad dose as compared to other dosages.Changes in pectic fractions and PE activity were more pronounced immediately following irradiation in comparison to those occurring during ripening. The increase in soluble solids as well as sucrose, and the decrease in AIS, titratable acidity, reducing sugars and firmness during ripening proceeded at faster rates in control fruit than in the irradiated fruit. These variable rates of change were reflected by the significant irradiation dose and storage duration interactions.Results suggest that irradiation induces a delay in ripening of Kent mangoes.

Notes: SUMMARY— The role of various polyphenolic compounds in oxidations catalyzed by apple polyphenol oxidase (PPO) was investigated. Quercetin, quercitrin, rutin, cyanidin chloride, phloroglucinol, and resorcinol were neither substrates nor inhibitors of apple PPO. Phloroglucinol and resorcinol increased the rate of PPO catalyzed oxidation of chlorogenic acid.Esculetin and dihydroquercetin were found to be substrates of PPO. No synergistic effect was detected in the browning rates of an esculetinchlorogenic acid mixture or a dihydroquercetin-chlorogenic acid mixture. Ferulic acid, fisetin, and p-coumaric acid were generally non-competitive inhibitors, although ferulic acid inhibited competitively in one test. It was hypothesized that the conjugated system in flavones prevents these compounds from being apple PPO substrates.

Notes: SUMMARY— A procedure is described for isolating compounds formed during the heating of solutions containing sugars and amino acids. It consists of solvent partition into ethyl ether, concentration of the solvent, high vacuum distillation in an isolated system and a final concentration. Model systems were employed, consisting of one sugar and one source of amino acids from the group: dextrose, lactose, glycine, lysine, valine, and casein. The flavor concentrate had a strong caramel odor.A total of 38 non-acidic and 5 acidic gas chromatographic components were observed, but none of the systems gave rise to all of these. The differences in the gas chromatographic patterns of extracts containing both sugars and amino acids and those containing sugars alone, were more quantitative than qualitative.While many of the components remain unidentified, those positively identified were largely sugar dehydration and degradation products. One nitrogen-containing component was identified as 2-acetylpyrrole.

Notes: SUMMARY— The distribution of lactate dehydrogenase (LDH) in chicken breast muscle was studied by preparing subcellular fractions by homogenization and differential centrifugation under conditions known to cause the enzyme to be associated with the particulate structures. The LDH was widely distributed among the subcellular fractions with the outer cell membrane and the mitochondrion having especially high activities associated with them.A 4-hr aging period of the whole, excised muscle had only a minor effect on the subcellular distribution of the enzyme. The major change in aged muscle was an increase of enzymic activity in the soluble, supernatant fractions. Although certain possible artifacts have been ruled out, it is not completely certain that the particle-associated LDH is a true reflection of the situation in vivo. There is at least, however, a reproducible pattern to the binding of LDH to the individual subcellular fractions when chicken breast muscle is homogenized under the specified conditions.

Notes: SUMMARY— Results obtained by a thermal extraction procedure for determining the fat content of fresh ground beef were found to correlate significantly (1% level) with results obtained by the official AOAC solvent extraction procedure. The fat levels investigated ranged between 14 and 29%. As the amount of sample grinding increased, the fat variation within thermal extraction replications decreased, while the differences between the thermal and solvent extracted fat became larger.Linear regression between the two methods contained significant error in certain areas of the fat range tested. The fourth order polynomial provided the best fit curve between the solvent and thermal extraction data for thermal samples ground once through a plate having g-in. diameter holes and twice through a plate having holes 1/8-in. in diameter. The thermal extraction method, being adequately reproducible, rapid, and economical, provides a valuable tool to the food industry in control procedure and to the Armed Forces in its quality assurance tests.

Notes: SUMMARY— The water-extractable soybean proteins (WESP) were fractionated into five fractions by gel filtration with Sephadex G-200 column. Four of the five fractions were protein fractions, while the fifth fraction was nonprotein fraction. The first two fractions were heterogeneous by sedimentation analysis, while the third and fourth fractions give homogeneous fractions with 7s and 2s respectively. The trypsin inhibitor activity was found only in the fourth fraction.

Notes: SUMMARY— Solubility of intramuscular collagen was studied as affected by chronological maturity in 15 bovine longissimus dorsi and 15 semimembranosus muscles and as affected by post-mortem contraction state in the semitendinosus of 7 animals. Collagen solubility decreased significantly with each advancing maturity group in both longissimus dorsi and semimembranosus muscles. Collagen solubility was also higher (P 〈 0.05) in the longissimus dorsi than in the semimembranosus, except in the E maturity group. It was also related to panel tenderness in both muscles (r = 0.77 and 0.81 (P 〈 0.01) for longissimus dorsi and semimembranosus muscles, respectively. However, within-maturity group correlations of solubility of collagen and tenderness were low and nonsignificent.Collagen content did not differ significantly in longissimus dorsi muscles of animals of A, B, and E maturity groups; however, the semimembranosus had more collagen (P 〈 0.05) in E than in A and B maturity groups. Collagen content was not related (P 〉 0.05) to panel tenderness in either muscle (r =−0.42 and −0.48 for longissimus dorsi and semimembranosus, respectively). Neither collagen solubility nor collagen content was significantly affected by post-mortem contraction state. Furthermore, collagen solubility did not increase significantly with post-mortem aging up to ten days.

Notes: SUMMARY— A direct, objective method was developed for measuring the cohesive force holding the fibers and fiber bundles of poultry meat together, i.e., the connective tissue tenacity. The method consists of cutting out uniform cylinders of cooked muscle with the fibers parallel to the plane ends of the cylinder, attaching metal plates to the cylinder ends by a special adhesive that forms strong bonds with moist tissue, and measuring the force and work required to tear the meat sample apart in a recording tensile tester. Ability of the method to measure the cohesiveness between fibers, independent of the force required to shear across the fibers, was evaluated by determining connective tissue tenacity, shear force, alkali insoluble hydroxyproline (index of collagen), and taste panel reactions on cooked muscle samples varying with respect to age of bird, post-mortem aging condition, freeze-drying, and cooking time. Connective tissue tenacity was directly correlated with alkali insoluble hydroxyproline (r = 0.91, P 〈 0.001), inversely related to cooking time, and in general appeared to be a good measure of the connective tissue component of toughness as differentiated from the component related to force required to shear across the fibers. The method will be useful in objectively measuring the quality defect of lack of cohesiveness in canned, freeze-dried, and irradiated poultry meat, and should be of general value in all research on meat quality.

Notes: SUMMARY— Investigations on the physico-chemical properties and a sensory evaluation as a component of Shiitake flavor were carried out with lenthionine, a substance which was isolated from dried Shiitake mushroom. Lenthionine is practically insoluble in water but soluble in non-polar solvents. Its stability in an aqueous solution changes greatly with the pH of the solution.Lenthionine was identified as a significant component in the aroma of Shiitake mushroom and its detectable threshold level is at a concentration between 0.27 and 0.53 porn in water. This new aroma-bearing substance will be used as a flavor additive in various foods.

Notes: SUMMARY— The fatty acid composition of the lipids extracted from Georgia Red and Centennial varieties of sweet potatoes was studied to determine changes during storage at 15.5, 10, and 4.5°C. The two varieties did not differ initially in the relative proportions of fatty acids. However, changes in fatty acid composition were noted during storage and appeared to be mere pronounced at low storage temperatures. The most consistent changes noted were an increase in tetra-cosaenoic acid and a decrease in short chain saturated acids. The Centennial variety contained higher levels of total lipids, which were generally reflected in higher levels of the three fractions, (1) non-phospholipids, (2) cephalin and (3) lecithin. The increase in total lipids and the individual lipid fractions with storage is indicative of two processes that may have occurred in the stored roots. The lipids may have become more extractable as the respiring potato underwent compositional changes, or lipids were being synthesized from non-lipid components. Although changes observed in the relative proportions of fatty acids during storage at different temperatures were not always consistent, the possibility is suggested that changes in fatty acid composition may be related to changes in quality of the potato during storage.