June 3, 1922] 



NATURE 



iz-^ 



The cycle repeats indefinitely. The arrangement 

 might be used at low frequency for flashing signs, 

 at audio-frequency for telephonic measurements, and 

 at high frequency (up to about 15,000 ~) for radio- 

 signalUng. — A. Griffiths and W. T. Heys : A new 

 apparatus for the measurement of the polarisation 

 capacity of platinum plates in sulphuric acid. 

 Corrections can be made for leakage and self- 

 depKDlarisation of the cell. It gives results consistent 

 to one or two per cent., and of the same order of 

 magnitude as those obtained by other observers. — 

 Herbert Chatley : The molecular forces involved in 

 cohesion. Cohesion may be expressible as a function 

 of molecular masses or of electronic charges. In 

 either case it will also comprise a space-function, 

 and attention may be concentrated on the latter. 

 The f* law suggested by Sutherland's theory and 

 Van der Waal's rule, would indicate a greater difference 

 in strength than exists in practice between amorphous 

 substances and crystals. The crystal lattice elucidated 

 by Bragg implies a very gradual space-gradient of 

 force as compared with non-crystalline matter. The 

 y* law is also inconsistent with the Cavendish 

 experiment. Results more consistent with facts are 

 obtained with an y-* law. 



Association of Economic Biologists, May 19. — 

 Prof. E. B. Poulton, president, in the chair. — \V. 

 Rushton : Further contributions to the biology of 

 freshwater fishes. A short account is given of the 

 effects of the effluents from a series of distilleries, 

 a woollen-mill, and from town sewage on the sper- 

 matozoa of trout. The life of the sperms is affected, 

 but the eggs can be fertilised in the presence of the 

 effluents. The effects of tree felling on the water 

 supply to a trout hatchery was an increased acidity 

 causing the appearance of a " bloom " on the sides 

 and gills of the young trout, together with a coagula- 

 tion of the mucus, which resulted in death. — J. H. 

 Priestley : The toxic action of illuminating gas on 

 plants. It has been known for many years that the 

 presence of very small traces of unburnt coal gas in 

 the atmosphere may produce a harmful effect upon 

 growing plants under certain conditions. German 

 observers were the first to notice how very sensitive 

 " etiolated " shoots (the shoots of plants grown in 

 continuous darkness) of the pea or potato or many 

 Other plants are to the presence of traces of gas. 

 American workers have since extended these observa- 

 tions, and have shown that traces of coal gas in the 

 atmosphere or the fumes from cigarette smoke or 

 smouldering paper might have a very deleterious 

 action upon plants, especially upon such etiolated 

 shoots. Both German and American workers agree 

 that the deleterious effects of coal gas or these other 

 fumes can be traced to the gaseous unsaturated 

 hydrocarbons, such as ethylene, always present in such 

 fumes. If etiolated shoots or roots are placed in an 

 atmosphere contaminated with coal gas or pure 

 ethylene they cease to grow in length and expand 

 in girth instead. These changes in form can be 

 associated with changes in internal structure, notably 

 with the disappearance of the functional primary 

 endodermis. This endodermis forms close behind 

 the growing point in both the etiolated shoot and in 

 the root, and its disappearance seems to account in 

 large measure for the other structural changes 

 and abnormalities of growth seen in plants poisoned 

 by traces of coal gas. The disappearance of the 

 endodermis in the presence of fumes containing 

 unsaturated hydrocarbons can be attributed to the 

 displacement by these substances of the unsaturated 

 fatty acids which normally accumulate upon the walls 

 of the developing endodermis and give this tissue 

 its characteristic properties. The normal leafy stem 



growing in the light does not develop such an endo- 

 dermis. and proves relatively insensitive to the 

 presence of these gaseous unsaturated hydrocarbons. 

 These results are of some practical interest in that 

 they suggest diagnostic features by which the occur- 

 rence of gas poisoning in horticultural practice may 

 be recognised. The effect is produced by such very 

 low concentrations of ethylene — of the order of 

 one in a million — that although normal British 

 illuminating gas contains very small quantities of 

 ethylene, toxic effects may be produced by traces of 

 the gas too small to be detected by smell. In fact 

 the most delicate test we have for a gas leak possibly 

 consists in the behaviour of etiolated shoots growing 

 in darkness in the contaminated atmosphere. These 

 results may also be of some interest to municipalities 

 interested in the growth of shade trees along urban 

 routes. The gas leaking from the pipes in the soil 

 may be retained around the roots long enough to do 

 damage because of the impermeable nature of the 

 macadam or asphalte of the road surface. 



Paris. 



Academy of Sciences, May 8. — M. Emile Bertin 

 in the chair. — The President announced the death 

 of M. Ren6 Benoit, correspondent for the section of 

 general physics, and of Sir Patrick Manson, corre- 

 spoiident for the section of medicine and surgery. — 

 A. Haller and Mme. Ramart : The dehydration of 

 2-methyl-2-phenyl-i-propanol and of 2-2-dimethyl- 

 3-phenyl-i-propanol. The product varied with the 

 method of dehydration (passage of vapours over 

 infusiorial earth at 300°-400° C, action of SOClj 

 with or without pyridine). Substituted ethylenes 

 were obtained, the physical and chemical properties 

 of which are given, together with the oxidation 

 products establishing their identity. — C. Guichard : 

 The asymptotic Hnes of surfaces. The study of a 

 particular case. — P. Montel : A new theorem of 

 algebra. — J. Sudria : A demonstration and the 

 generalisation of Menabrea's theorem. — D. Riabou- 

 chinski : Some cases of plane movements of fluids 

 round solids with vortices. — Th. De Donder: An 

 electromagnetic field comparable with the corre- 

 sponding gravific field. — L. Roy : The electro- 

 dynamics of homogeneous isotropic media in repose. 

 — A. Bigot : Kaolins, clays, bauxites, etc. Porosity 

 and loss on heating. The loss on ignition of bauxites 

 and kaolins of different origin at temperatures up to 

 900° C. are shown graphically, and a second diagram 

 shows the changes in porosity of the same materials. 

 M. Palfray : Neutral homocamphoric esters and 

 their reduction products. — J. Froidevaux : The 

 estimation of ammoniacal nitrogen in nitrogenous 

 organic material, particularly in proteid materials, 

 and their products of hydrolysis. The liquid is 

 treated with a large excess of concentrated caustic 

 soda solution, and the ammonia removed by a 

 purified air stream without heating, with subsequent 

 correction for ammonia formed from the proteid. — 

 A. Schoep : BecquereUte, a new radioactive mineral. 

 This is found as a yellow crystalline crust on pitch- 

 blende from the Kasolo Mine (Belgian Congo). Its 

 composition is VO3 . 2H2O.— A. Gruvel : The fluvial 

 origin of the bay of L6vrier. The discovery of two 

 species of Potamides proves that the bay of L6vrier 

 is the ancient estuary of a large river. — P. Thi^ry : 

 The limit of the Bathonian and the Bajocian in 

 Lorraine. — J. B. Charcot : The temperatures at 

 different depths in the chasm of Cap Breton. Ob- 

 servations on the variation of the temperature of 

 the sea in the neighbourhood of this gap in the sea- 

 floor agree with the views recently put forward by 

 M. Gorceix, but are opposed to the results of P. E. 



NO. 2744, VOL. 109] 



