April 5, 19 17] 



NATURE 



1 1 1 



cave excavated beneath the quadrangle. The Pub- ^ 

 lication referred to contains the records of these > 

 instruments for the whole of the year 19 16, and Press 

 notices of earthquakes which occurred during the 

 same year in various parts of the world. The in- 

 fluence of the war is shown by the fact that all but 

 ten of these earthquakes were of American origin. 



The Department of Mines of the South Australian 

 Government has recently issued its first metallurgical 

 report. The authw is Mr. J. D. Connor, the Gov^ti- 

 ment metallurgist, who has undertaken a visit to the 

 United States of America with the view of studying 

 the recovery of cc^per from its ores by leadiing and 

 precipitation. His object was to secure such in- 

 formation as might assist in rendering available for 

 realisation the mineral assets of South Australia, and 

 in particular the unworked oxidised copper ores of 

 the northern mining fields. Too much stress cannot 

 be laid on the absoluf? necessity for exhaustive experi- 

 mentation before any attempt is made to deal with the 

 problem of leaching copper ores on a large scale. 

 The principle of insisting on properly controlled tests 

 before a working plant is erected is applicable to 

 almost every metallurgical proposition. >Ir. Connor's 

 visit was not so successful in its outcome as he had 

 anticipated. Although he travelled more than 10,000 

 miles, he saw only two leaching plants in actual opera- 

 tion, one of a capacity of 2000 tons a day, and the 

 other an experimental plant of 40 tons per day. He 

 did not visit the great plant at Chuquicamata, in 

 Chile, where 10,000 tons of ore are leached per day. 

 His general conclusion is that the leaching of copper 

 ores is not being carried out in the United States 

 to anything like the extent that might have been 

 anticipated considering the amount of literature on 

 the subject. A great deal of experimental work has 

 been done in the past by very able of>erators backed 

 by large organisations. To a considerably less extent 

 this work is going on now, but it has been completely 

 put into the background by the recognition of the 

 possibilities of the "flotation" process (see Nature, 

 March 22). That American metallurgists should have 

 been so long in taking up this process is certainly 

 surprising, but now that they have done so, and par- 

 ticularly after litigation difficulties have been removed, 

 it is likely that great developments will take place. 

 As yet oxidised ores are not susceptible to treatment 

 by flotation processes. 



In view of the movement for ihe establishment in 

 France of a number 01 national laboratories at which 

 the scientific problems which arise in the industries 

 may be investigated, ha Nature has commenced the 

 publication of a series of articles dealing with the 

 laboratories which have been founded in other 

 countries for the same purpose. On account of the 

 prominent position the National Physical Laboratory 

 at Teddington has made for itself in the short time 

 it has been in existence, it has been chosen as the 

 first of the series, and in the issue of La Nature for 

 March 10 a well-illustiated article giving an account 

 of the foundation, method of management, and 

 equipment of the laboiatory appears. 



The British Journal Photographic Almanac for this 

 year has at length appeared. Present circumstances 

 have not only delayed its issue, but reduced its size 

 to little more than the half of what it used to be; 

 still, it is a bulky volume of 780 pages. The maximum 

 number of pages allowed to any one advertiser having 

 been very much red iced, some manufacturers' an- 

 nouncements are a great deal more condensed than 

 heretofore, but the advertisement pages remain a very 

 ' '-^d guide to the various branches of the trade. The 

 pitome of Progf-ess " is curtailed chiefly with 



NO. 2475, VOL. 99] 



regard to kinematography, the literature of which 

 published during the last year is very voluminous. 

 The new British-made developers are included in 

 the tables of formulae. The section referring to 

 sensitisers and dyes for colour-filters remains very 

 much as before. The editor's article treats in a lucid 

 manner with the elementary principles of chemistry 

 so far as concerns the practice of photography, an<i 

 this, therefore, is an appropriate time to point out 

 a chemical error that is of many years' standing. 

 The lengthy and useful table of chemical names, 

 symbols, and atomic weights of numerous com- 

 pounds has the atomic (or molecular) weights given 

 described as "equivalent weights," which, of course, 

 they are not. 



The Biochemical Journal for December, 1916, con- 

 tains an important paper by Mr. H. Ackroyd and Prof. 

 F. G. Hopkins, entitled " Feedine Experiments with 

 Deficiencies in the .Amino-acid Supply : Arginine and 

 Histidine as Possible Precursors of Purines." In 

 the authors' experiments young growing rats were 

 fed first on a diet composed of acid-hydrolysed 

 caseinogen, f>otato-starch, cane-sugar, lard, butter, 

 and ash from equal weights of oats and dog-biscuit, 

 then on the same diet from which the arginine and 

 histidine had been removed, and finally on this second 

 diet plus arginine or histidine, or both. The neces- 

 sary vitamine supply was given in the form of a 

 protein-free alcoholic extract of fresh-milk solids. In 

 other experiments the tr}-ptophane or the vitamine 

 was absent from the diet. The results show that 

 when both arginine and histidine are removed from 

 the diet there is a rapid loss of body-weight of the 

 rats, and a renewed growth when the missing 

 diamino-acids are restored. Nutritional equilibrium 

 is possible in the absence of one of these protein con- 

 stituents, but not in tne absence of both. The sug- 

 gestion is made that this is because each of the two 

 diamino-acids can, in metabolism, be converted into 

 the other. If both arginine and histidine are removed 

 from the food, the amount of allantoin excreted is 

 much diminished, but the decrease is very much less 

 when only one diamino-acid is removed When both 

 are replaced, the excretion returns to the normal. 

 When tr>-ptophane or vitamine is removed from the 

 food there is no decrease in the amount of allantoin 

 excreted, although nutritional failure is then greater 

 than when arginine and histidine are withheld. It is 

 accordingly suggested that these two diamino-acids 

 play a special part in purine metabolism, probably 

 constituting the raw material for the synthesis of 

 the purine ring in the animal body. 



The registrar of the Institute of Chemistry is parti- 

 cularly well situated to appreciate the important part 

 played by chemists in the war, since he has had control 

 of the register of chemists available for Government 

 and other services maintained by the Institute. This 

 fact adds an enhanced interest to the article " Chemists 

 in War " which he contributes to the Proceedings of 

 the Institute for February. The general community is 

 fK-obably at last beginning to know that the rdle of the 

 chemist in the manufacture of high explosives is all- 

 important, but it is very doubtful whether it realises 

 even j'et that his help is necessary in the production 

 of all metals, cloth, leather, india-rubber, glass, food, 

 pure water, and medicine — in fact, of practically every 

 article of everyday life. Many chemists have been 

 appointed to commissions in the Royal Army 

 Medical Corps, the Army Service Corps, and 

 the Army Ordnance Corps, whilst in order 

 to fight the German with his own weapon, a 

 special force of chemists was enlisted for the 

 I preparation and employment of poisonous gas at 

 I the front in. Flanders. The chemists employed in the 



