Abstracts of Papers Communicated to the Royal Society of LondonSource: Proceedings of the Royal Society of London. Series A, Mathematical and PhysicalSciences, Vol. 177, No. 971 (Mar. 18, 1941), pp. S9-S12Published by: The Royal SocietyStable URL: http://www.jstor.org/stable/97473 .

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ABSTRACTS

OF P4APERS COMMUNICATED TO THE ROYAL SOCIETY OF LONDON In accordance with a resolution of Council, summaries or abstracts of papers are to be published as soon as practicable. The publica- tion of such abstracts in no way indicates that the papers have been accepted for publication in any fuller form. These abstracts are issued for convenience with the " Proceedings of the Royal Society of London " but do not form a part of the " Proceedings".

8 MARCH 1940

Crystal boundaries in tin. By B. CHALMERS. (Communicated by E. N. da C. Andrade, F.R.S.-Received 2 December 1939.)

A new technique is described for preparing specimens of tin consisting of two crystals of controlled orientation, of such a size and shape that a tension can be applied transversely to the boundary. It is found that the temperature at which the crystals separate under tension is below the melting point of the crystalline material, and that the difference is independent of the angle between the crystal axes of the two crystals and of impurity providing this does not exceed about 002 %. The mechanism of boundary formation is considered, a distinction being drawn between two types of boundary described as " columnar " and " segregational ". The structure of the boundary is discussed in the light of the new experimental evidence, which favours a "transitional lattice" rather than an "amorphous layer" theory.

The paedogenetic male cycle in Salmo salar L. By J. W. JONES and J. H. ORTON. (Communicated by C. T. Regan, F.R.S.-Received 11 December 1939.)

In a further study of the male sex phases throughout the year in salmon parr- accompanied by histological investigation of the gonad-the earlier observations have been confirmed. Some 2790 parr and smolts, captured mainly by rod and line from English and Welsh rivers, have been examined; 50 % of these were male. All the females are immature virgins; the males exhibit a seasonal sexual cycle in which the gonad develops in the summer, becomes mature in the autumn and is

Abstracts [ S 9 ] 3

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8 10 Abstracts of Papers

spent in winter. After spawning, a high proportion of the male parr migrate to sea as smolts. All the male smolts examined, i.e. 490, had quiescent testes, being either spent or immature and virgin. It is hereby established that two types of male smolts migrate to sea. The gradual disappearance of ripe male parr during the spawning season (beginning about November) and the correlated appearance and increase of males with spent gonads renders it virtually certain that t1he ripe male parr spawn on the salmon redds.

The temperature ranges in the rivers during the development of the male gonad is noted.

The finding of only 60 % spent amongst the migrating smolt males as against 75 % ripe spending and spent male parr in the preceding spawning period, November and December, may be an indication of a slight mortality among the spawning males.

The sex records given herein, along with those of ripe parr in the literature, leave no doubt that paedogenesis in the male of the Atlantic salmon occurs throughout its geographical range.

The remarkable paucity of males amongst the younger classes of immigrating salmon noted by Hutton on the Wye may be general and be compensated biologically by the abundant paedogenetic males.

Histological changes in the testis in the sexual cycle of male salmon parr. By J. W. JONES. (Communicated by C. T. Regan, F.R.S.-Received 11 December 1939.)

Over 2500 salmon parr and smolts have been examined for condition of the gonad. The male gonads were classified according to the nomenclature of the International Council. All female gonads were immature, and the development of the male gonad was found to be seasonal. Spermatogenetic development begins from late May to July, and ripe sperm was first noticed in late September. The greatest percentage of ripe testes was taken in late October and November (the adult spawning time), during which period ripe sperm was extruded on the application of slight pressure to the abdomen. From November-December to June-July spent testes in various stages were found.

The ripening and spending of the testes may be followed macroscopically. The youngest testes sampled are paired thread-like bodies extending the length of the body cavity. As development proceeds the testes widen anteriorly; such widening extends backwards with increase in size. The ripe testes occupy almost all available space in the body cavity. The rosy pink colour of the thread-like immature testes changes to the greasy white of the almost ripe condition (stages IV and V), and even- tually the milky white of a ripe testis.

As spawning proceeds a general collapse of the testes takes place, accompanied by a correlated series of colour changes. When almost all the sperm had been extruded the testes were similar in size to the II and II + developmental stages, but were of a peachy pink colour with white spots of relict sperm, and often with much relict

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Abstracts of Papers S 11

sperm in the wide collapsed ducts. In the last stage in spending which could be ascertained macroscopically the testis was of a fawny colour with faint longitudinal striae, and had a rather wide duct.

Spermatogenic changes in the tube-like stage I were confined to an inward migration of the germ cells and their transformation into germ mother cells. These cells are large with lightly staining nuclei and cytoplasm and one or two plasmo- somes; in the I+ stage they are more numerous and begin producing occasional spermatogonia. Further increase in size of the gonads is correlated with an increase in the number of the later spermatogenic products. Sperm appears in the larger II + stages and is fairly abundant in the stage III gonads. Sperm increased in number at the expense of the earlier germ cells. In the almost ripe stage V testis and the ripe stage VI the testicular crypts are full of sperm with a few spermatids: secondary spermatocytes occur in the very tenuous crypt walls.

With the collapse of the testes due to extrusion of the sperm the outer testicular tunica becomes thicker and folded, the crypt walls become more pronounced, and the crypt cavity decreases in size. Germ mother cells reappear in the emptied testes; it is thus possible that the testes may develop more than once in the river.

No actively developing testes were found in the migrating fish.

The dehydration of crystals of chrome alum. By J. A. COOPER and W. E. GARNER, F.R.S. (Received 27 December 1939.)

Measurements have been made of the rate of growth of dehydration nuclei over the 111 surfaces of crystals of chrome alum for a range of temperatures. These rates have been compared with the rates of penetration into the crystal. The self-cooling of the crystals has been measured and the heat of dissociation calculated both from the self-cooling and the temperature coefficient of the dissociation pressure. The heat of dissociation, 10 kcal., is much less than the calculated activation energy for the dehydration, viz. 31 kcal. An explanation is advanced for the abnormally high activation energy.

It is shown that small pressures of water vapour cause an acceleration of the rate of dehydration.

Investigations of infra-red spectra. Determination of C-H frequencies (-3000 cm.-') in paraffins and olefins, with some observations on "polythenes". By J. J. Fox and A. E. MARTIN. (Communicated by Sir Robert Robertson, F.R.S.-Received 3 January 1940.)

The infra-red absorption spectra of some twenty hydrocarbons in carbon tetra- chloride solution have been studied in the region 2 6-3 8 , with the following results:

-CH2 groups in ethylene and higher olefins give rise to two CH frequencies with

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S 12 Abstracts of Papers

mean values 3079 and 2978 cm.-', corresponding, respectively, to unsymmetrical and symmetrical valency vibrations of the CH2 group.

>CH groups in olefins have usually a single CH valency frequency close to

3019 cm.-', i.e. almost half-way between the two bands of the -CH2 group. The

\CH frequency in saturated compounds is 2890 cm.-'.

\CH2 groups have normally two CR valency vibrations with mean values 2926

and 2853 cm.-', corresponding, respectively, to the unsymmetrical and symmetrical vibrations within the CH2 group. In long-chain paraffins the position of these bands and their intensity per CH2 group remain remarkably constant from one compound to another. As found previously, bands additional to these two may occur in some cases.

CH3 groups also have two main CH valency frequencies, corresponding to un- symmetrical and symmetrical vibrations within the CH3 group. These frequencies are close to 2962 and 2872 cm.-', respectively, when the methyl group is attached to another carbon atom, but in methyl bromide the frequencies are 3049 and 2958 cm.-', i.e. 87 and 86 cm.-' higher. The CH force constant in methyl bromide is almost exactly the same as in methane, and this indicates that the CH internuclear distance does not differ from that in methane by as much as OOO1 A. The CH force constant in a CH3 group attached to a carbon atom is nearly 6 % lower than in methane and methyl bromide. In saturated hydrocarbons the position of the methyl bands and their intensity per CH3 group remain fairly constant, but when a methyl group is adjacent to a double bond, as in propylene, the positions and intensities of the bands vary greatly from one compound to another for comparatively small changes in the molecule. The band near 2872 cm.-' is split in these compounds, the mean position of the two components being close to 2872 cm.-'. The total area of all the bands attributable to CH3 groups in the unsaturated molecules, although somewhat lower than in saturated compounds, is still, however, approximately proportional to the number of CH3 groups present.

Identification of the cis and trans forms of 2-butylene is readily carried out by examination of the infra-red spectra. A striking resemblance exists between the spectrum of the trans form and that of propylene.

Two samples of a polythene (condensed ethylene resinoid) have been examined and have spectra similar to those of long-chain normal paraffins. A band at 2960 cm.-l characteristic of the methyl group is found in all cases and the proportion varies from I CR3: 8 CH2 for the most soluble part of the polythenes to 1 CH3: > 0 CH2 for the whole sample. The significance of these results in relation to X-ray examination is briefly discussed.

CH force constants are given for eleven varieties of CH bond, and mean integrated

absorption areas are given for ICH, 3CH, ==CH2, CH2 and CH3 groups. 7

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