March 7, 19 18] 



NATURE 



less efficient utilisation of feed by the fattened as com- 

 pared with the thin animal, the unit of a resorbed 

 nutrient producing, according to this view, less fat in 

 the latter case, while the heat production of the body 

 should be correspondingly greater. In order to test this 

 view by a direct comparison of the utilisation of feed 

 energy by the same animal in ordinary condition and 

 when well fattened an investigation has been carried 

 out by Messrs. H. P. Armsby and J. A. Fries at the 

 Institute of Animal Nutrition of the Pennsylvania State 

 College, the results of which are published in the 

 Journal of Agricultural Research, vol. xi.. No. lo. No 

 difference was found in the efficiency of digestion of 

 the food by the animal in lean or fat condition, nor 

 was there any measurable difference in the percentage 

 of the gross energy of the feed which was meta- 

 lisable. The heat increment resulting from the con- 

 niption of a unit of feed was but little greater, and 

 iisequently the net energy value of the feed but 

 i^jhtly less, in the fattened than in the unfattened 

 iidition. The increased maintenance requirement of 

 the fattened as compared with the lean steer was 

 greater than corresponded with the increase in weight 

 or in computed body surface. The lower economic 

 efficiency of the fattened animal in this experiment 

 \\ as thus due chiefly to his higher maintenance require- 

 ment, and only to a small extent, if at all, to a differ- 

 ence in the utilisation of the surplus of feed above 

 the maintenance requirement. 



A NEW instrument for the determination of sea-water 

 <ipnsities on board ship is described by Mr. A. L. 

 ' Iiomas in the Journal of the Washington Academy of 



iences for December 19, 1917 (vol. vii.. No. 21). It is 

 a modification of the total immersion hydrometer, and 

 ■consists essentially of a test-tube containing the float, 

 or bobbin, and the liquid to be measured, a stirred vari- 

 able temperature bath, and a thermometer. The bobbin 

 is about 5 cm. long and 12 mm. in diameter, and is 

 made of Jena glass. The glass test-tube holds 15 to 

 30 c.c. of the water to be tested. The temperature 

 bath, of copper and glass, holds about 270 c.c. of water, 

 and can be rapidly heated electrically. The method of 

 making a determination depends on noting the precise 

 temperature at which the liquid to be tested is exactly 

 ' f the same density as the bobbin, which is, of course, 

 when the bobbin neither sinks nor rises. By taking 

 the mean of the readings approaching the equilibrium 

 temperature from a higher and a lower temperature the 

 rosult may be obtained to 005° C. It is claimed that 

 he apparatus is simple and rapid to work, requires a 



nail amount of the Water to be tested, and gives 

 ,:> curate results. 



In the paper on " Switchgear Standardisation " 

 which Dr. C. C. Garrard read to the Institution erf 

 Electrical Engineers on February 21 many subjects 

 were discussed which are of special interest at the 

 present time. In connection with research. Dr. Gar- 

 rard pointed out that while the Department of Scien- 

 tific and Industrial Research expends a few hundred 

 pounds on "switching and arcing," a single Berlin 

 firm had recently expended about a hundred times as 

 much in building a laboratory for the specific purpose 

 of testing oil switches alone. He suggests that the 

 Metrical industry and the Government should co- 

 x-rate for the purpose of providing a national high- 

 nsion research and standardising laboratory. We see 

 > reason, however, why existing laboratories should 

 t be utilised in the first place to the fullest possible 

 \rent. Several grandiose schemes on a similar scale 

 have been discussed by various committees recently, 

 rhey all start with the assumption that generous 

 NO. 2523, VOL. lOl] 



financial support will be given by the Government. 

 In the discussion several speakers pointed out that 

 standardisation has its limitations. It would be 

 foolish, for instance, to standardise devices which are 

 being improved from day to day. Such a procedure 

 would simply mean the placing of an embargo on 

 invention. Mutual co-operation is in every way desir- 

 able, but when interests are antagonistic it cannot be 

 obtained. To force private firms to pool their in- 

 formation for the general good would in many cases 

 simply amount to confiscation of capital ; it is only human 

 that manufacturers should desire to keep their trade 

 secrets. The question also as to how far it is desir- 

 able to make devices " fool-proof " was discussed. The 

 general opinion was that the great series of campaigns 

 originated in America with the cry of " safety first " 

 has now gone too far. To expend ingenuity in mak- 

 ing devices "fool-proof" is desirable, but to try to 

 make them absolutely "fool-proof" is in manv cases 

 pure waste of time. 



From the specific gravities of certain substances, 

 that of water at different temperatures, and 

 those of the solutions of these substances in water, 

 Mr. J. N. Rakshit has calculated the contraction of 

 volume resulting when a fixed quantity of each sub- 

 stance is dissolved in increasing quantities of water. 

 The results are tabulated in the Proceedings of the 

 Indian Association for the Cultivation of Science (vol. 

 iii., part iv.), the substances dealt with being hydro- 

 chloric, sulphuric, nitric, formic, acetic, and tartaric 

 acids; stannic and sodium chlorides; ammonia, sodium, 

 and potassium hydroxides ; methyl, ethyl, propyl, iso- 

 butyl and tsoamyl alcohols, glycerol, phenol, dextrose, 

 laevulose, maltose, invert- and cane-sugars, acetone, 

 chloral hydrate, acetonitrile, and nicotine. Study of 

 the figures obtained shows that in some cases the con- 

 traction of volume increases with the increase in dilu- 

 tion, but in several others as the dilution increases a 

 point of maximal contraction is observed. The maxi- 

 mum contractions are constants, and different for 

 different substances. In the cases of sodium chloride 

 and of acetic and sulphuric acids the contraction of 

 volume at all dilutions diminishes as the temperature 

 rises. It is not yet known whether this phenomenon 

 is due to differences in the coefficients of expansion of 

 water and of the solute. 



A NEW book by Sir Ray Lankester is being brought 

 out by Messrs. Methuen and Co., Ltd., entitled 

 " Secrets of Earth and Sea," in which the following 

 subjects will be dealt with : — The mammoth rts 

 drawn by those who lived with it; the " rostro-carin- 

 ates " — the earliest works of man; Vesuvius in erup- 

 tion ; pond-life ; gregarines and malaria ; a mere worm 

 (the earth-worm) ; what is meant by a species ; the 

 classification of animals ; geological strata ; about 

 fishes (flying-fish, climbing-fish, blind-fish, cave-fish, 

 deep-sea fish) ; the races of man ; Darwinism and war ; 

 German culture; spider-sense and nonsense; belief and 

 evidence; the Svastika. Other books in Messrs. 

 Methuen 's new list are: — "Glossary" and Notes on 

 Vertebrate Palaeontology," the Rev. S. A, Pelly ; "The 

 Fisheries of the North Sea," N. Green; and "Food 

 and Garden," H. A. Day. 



Catalogue No. 71, just issued by Messrs. Dulau 

 and Co., Ltd., 37 Soho Square, W.i, contains par- 

 ticulars of books and papers from the library of the 

 late Dr. A. M. W. Downing, and other sources. 1 

 refers in the main to works on astronomy and astrci- 

 physics, but also gives the titles of books relating to 

 engineering, geology, and mathematics. 



