I30 



NATURE 



[April 6, 1916 



Mr. Sato used both mercury and platinum resistance 

 thermometers in his pipes, and compared their records 

 with those of similar thermometers placed directly in 

 the ground at the same heights. He finds that the 

 records of the thermometers in the pipes differ both 

 in amplitude and in phase from those of the thermo- 

 meters in the ground, and that the difference is due 

 to the heat conductivity of the material of the pipe 

 and to the convection currents in the air in the pipe. 

 It persists when a poor heat conductor is substituted 

 for iron and when the depth of the pipe is increased. 

 As a result, almost all the values of the thermometric 

 conductivity of soils deduced from observations of 

 temperatures in pipes are too high. 



Since the outbrealv of the war it has been impossible 

 to obtain the magnetite anodes which have played so 

 important a part in electro-chemical industry, as all 

 these were made in Germany. A note is contained 

 in the Chemical Trade Journal of March 4 on the 

 introduction of a substitute for these in the form of 

 "duriron" anodes, made of an iron silicon alloy. 

 Whilst this material is not entirely unacted on when 

 used as an anode in copper sulphate solution, from 

 fifteen to twenty times its weight of copper can be 

 deposited before it is entirely corroded away. Duriron 

 anodes have a higher mechanical strength than mag- 

 netite, but require about 13 per cent, more electrical 

 energy to deposit the same quantity of copper. The 

 extra power goes into heat, and special precautions 

 have to be taken to avoid too high a rise in tempera- 

 ture. 



A BOLD article by Mr. C. A. Jacobson on the need 

 for a large Government institution for chemical re- 

 search, which appeared in the Journal of Industrial 

 and Engineering Chemistry, is reprinted in the 

 Chemical News (vol. xliii, p. loi). The scheme out- 

 lined involves the creation of an institute of chemical 

 research on a colossal scale, consisting of fifty major 

 departments and pne hundred minor departments, com- 

 prising about fifty buildings, a staff of 1350 trained 

 workers, and an expenditure of more than a million 

 pounds sterling per annum. A few years back such an 

 idea would have sounded utterly Utopian and impos- 

 sible, but, in face of a war expenditure In this country 

 alone every day of five times the amount called for 

 each year b}' such a scheme, the outlay seems small 

 If thereby supremacy w^ere ensured "in a branch of 

 science which Is not only vital to constructive agencies, 

 but even more so to destructive ones. The present 

 European war teaches us that men and military train- 

 ing are of far less importance to success than a high 

 development of the science of chemistry." 



A RECENT issue of The Engineer (March 24) con- 

 tains an account of the Medlow Dam, situated In a 

 sandstone gorge on Adams Creek in the Blue Moun- 

 tains of New South Wales. The dam is remarkable 

 for Its slender profile, having a base width of only 

 896 ft., tapering to 35 feet at a height of 29 ft., from 

 which level the thickness remains unaltered to the 

 coping at a height of 65 ft. The wall is of plain 

 concrete, without reinforcement. Our contemporary 

 compares It with the old Bear Valley Dam In Cali- 

 fornia, which, with practically the same height, had 

 a base width of 20 ft., and was generally much more 

 substantial in design. The Medlow Dam is built to 

 a curve of 60 ft. radius, and cost 2762Z. The catch- 

 ment area is 1150 acres, with an average rainfall of 

 39 In. The dam holds up a lake having a surface 

 of 12 acres and containing 67 million gallons of water. 

 By means of an Inclined and adjustable off-let pipe 

 the water Is drawn off from the clearest stratum at the 

 top. 



The National Physical Laboratorj' has issued some 

 notes on the production and testing of screw gauges, 



NO. 2423, VOL. 97] 



written by members of the staff of the laborator) 

 and based on their experience. The Whitwortl 

 thread has seven elements, error on any one of whic 

 may be sufficient to cause a gauge to reject wor! 

 which ought to pass, or vice versd. These element 

 I are : Full diameter, core diameter, effective diametei 

 , pitch, angle, form at crest, form at root. Of these 

 the most important, and the most difficult to con 

 trol, are the pitch and effective diameter. The labor.? 

 tory is issuing specially selected needles for use wit! 

 the micrometer in testing the effective diameters 

 screws of 12, 14, 24, and 36 threads per inch. Th 

 methods of using these, together with special arrange 

 ments for holding the micrometer in the lathe, ar 

 described In the pamphlet. Triangular needles ar 

 used for testing the core diameter. There is als 

 described an Ingenious and cheap apparatus for testln; 

 the angle of the thread ; this apparatus can be pvi 

 together very easily In any workshop. The best wa 

 of obtaining correct pitches Is to cut a screw in th 

 lathe, using that part of the leading screw which I 

 to be used In cutting the gauges, and to have it 

 pitch measured from thread to thread at the labors 

 tory. The pamphlet contains a great deal of usefu 

 information, and should be read by everyone Inter 

 ested in accurate screw cutting. 



Prof. Karl Pearson, Galton Laboratory, Univer 

 sity College, London, W.C., informs us that he ha 

 lately completed the corrigenda for his "Tables fo 

 Statisticians and Biometriclans," published by th 

 Cambridge University Press, and that the list is no\ 

 bound with all exemplars of the tables. He wishe 

 it to be known that previous purchasers of the worl 

 can obtain a copy of the corrigenda by sending : 

 request for the same w ith a stamped envelope to Mr 

 C. F. Clay, Cambridge Press Warhouse, Fetter Lane 

 or to the secretary, Galton Laboratory, Universit; 

 College, London, W^.C. 



The following additional volumes have beei 

 arranged for, for inclusion in the " Fauna of Britlsl 

 India " series (Taylor and Francis) : — Lycaenidae an( 

 Hesperiidae, H. H. Druce; the Curculionidae 

 G. A. K. Marshall ; the Longicorn Beetles, C. J 

 Gahan ; the Ixodidae and Argasidae, C. Warburton 

 Leeches, W. A. Harding; the Brachyurous Crustacea 

 Lieut.-Col. A. Alcock; the Apterygota, Termitidae 

 and Embiidae, A. D. Imms; the Diptera Brachycera 

 E. Brunetti ; the Rntelidae, G. J. Arrow; and th( 

 Operculata, by G. K. Gude. 



Mr. Francis Edwards, 83 High Street, Marylebone 

 London, W., has issued a catalogue of Oriental book; 

 he is offering for sale. The works deal with the follow 

 Ing among other countries of the Far. East: — China 

 Japan, India, Burma, Tibet, and Persia. 



OUR ASTRONOMICAL COLUMN. 



Comet 1916a (Xeujmin). — Copenhagen Postcan 

 No. 12 glves^^an elliptic orbit for this comet, calcu 

 lated by M. J. Braae, from observations covering nine 

 days :— 



Epoch, 1916, January 0-5, G.M.T. Mo 348° 50' 21 

 a> =193=16' 2-o"] (p =36° 44' 33-2' 



Q, =327 20 4-0 -1916-0 fx =57 1 "493 

 / = II 5 34-3 J Log = 0528664 



Period, 2267-74 days (6-21 years). 



Perihelion passage, 1916, March 10805 G.M.T. 



The ephemeris calculated by Messrs. J. Braae am 

 J. FIscher-Petersen from these elements is given ir 

 the following summary : — 



From April 6, Greenivich midnight. 



R.A., gh. 36m. 7s., add for April 8, -|-3m. 31s 



