i88 



NATURE 



[April 27, 1916 



in geographical distribution. M. Adolf Hoel has a 

 paper on the subject in La Geographic for De- 

 cember, 19 15 (vol. XXX., p. 6). His contention that the 

 Spitsbergen reindeer have come from Novaya Zemlya 

 via Franz Josef Land is supported by a single piece 

 of evidence, but a very strong one.- In 1912 an old 

 male reindeer was shot in Spitsbergen that had 

 attached to one of its horns by a piece of cord the 

 foot of an ivory gull. It also had incisions on its 

 ears. There can be no doubt that these markings 

 on the horn and ears were the work of Samoyedes 

 on Novaya Zemlya, who are accustomed to distin- 

 guish certain members of their herds in this way. 

 Other reindeer with marked ears are said, but on 

 less secure evidence, to have been shot in Spits- 

 bergen. In any case, this particular deer was not 

 brought from Novaya Zemlya by man. From Novaya 

 Zemlya to Franz Josef Land is about 240 miles, from 

 Franz Josef Land to King Carl Land about 210, and 

 to Edge Island, Spitsbergen, another 55 miles. 

 Winter ice would certainly permit such a journey, 

 but the difficulty is to believe that a reindeer could 

 travel 240 miles without food. However, M. Hoel's 

 explanation seems the only possible one. A passage 

 direct from Lapland to Spitsbergen would be im- 

 possible, if only because there is never continuous ice. 



Part 2 of vol. xxviii. of the Proceedings of the 

 Physical Society of London contains thirty pages, 

 twenty of which are devoted to the Guthrie Lecture 

 delivered at the end of January by Dr. W. B. Hardy, 

 secretary of the Royal Society. He chose for his 

 subject some of the physical problems raised by the 

 study of living matter. He showed, for example, 

 how the growth of the severed end of a nerve towards 

 its corresponding end is determined by small differ- 

 ences of concentration of some substance diffusing out 

 from the severed ends. The phenomena of growth 

 depend on the presence of minute quantities of sub- 

 stances known as vitamines, often found exclusively 

 in the rinds or skins of grains and fruits, and Dr. 

 Hardy drew a parallel between their action in deter- 

 mining growth and the effect of throwing a few 

 crystals into a supersaturated solution. The remainder 

 of the part is devoted to a short paper by Prof. Lees 

 on a generalised bridge for the comparison of the self 

 and mutual inductances of two coils, and another by 

 Dr. Sand on a cadmium arc lamp similar in principle 

 to the mercury arc lamp. 



In 191 1 a paper was read before the International 

 Photometric Commission by W. J. A. Butterfield, 

 J. S. Haldane, and A. P. Trotter, describing some 

 careful experiments on the Pentane and Hefner 

 standard lamps. By enclosing these lamps in a special 

 chamber the effect on the light of carbon dioxide, 

 aqueous vapour, and barometric pressure could be 

 conveniently studied; with the great advantage that 

 variations far greater than those met with in practice 

 could be produced, and the resultant changes in 

 candle-f>ower studied on a large scale. In the case of 

 the Pentane lamp the results obtained were in close 

 agreement with those previously reported by C. C. 

 Paterson at the National Physical Laboratory. But 

 the correction for the effect of carbon dioxide and 

 change in barometric pressure on the Hefner lamp 

 were found to be respectively three times and four 

 times that previously assumed by Liebenthal. This 

 question has since been studied by Dr. Ott. of Zurich. 

 With the view of securing exceptional variations in 

 barometric pressure experiments were first made at 

 various stations in high altitudes, but eventually the 

 method of employing a compression chamber was 

 adopted. A change of barometric pressure from 816 

 to 717 mm., which is the most important range from 



NO. 2426, VOL. 97] 



a practical viewpoint, produced a variation in the 

 candlepower of the Hefner lamp of only I'l per cent. 

 This is in close agreement with Liebenthal 's formula. 

 But from 717 mm. to 6i4"5 mm. the variation in 

 candle-power was found to be much greater, and the 

 average effect for the entire range of 816-614*5 mm. 

 approximated very closely to the figure given by 

 Butterfield, Haldane, and Trotter. As regards the 

 effect of carbon dioxide Dr. Ott agrees with these 

 observers in finding the factor given in Liebenthal 's 

 formula too small, but this arises from the fact that 

 the presence of much carbon dioxide is in practice 

 usually due to the vitiation of the air of the photo 

 meter room. TTie light is thus affected by deficiency 

 of oxygen as well as the carbon dioxide. Well-ven- 

 tilated and sufficiently large rooms are therefore 

 essential for standard work. 



The accurate measurement of the vapour pressure 

 of ice at low temperatures is a problem of consider- 

 able difficulty, not only on account of the smallness 

 of the values involved, but also because of the adsorp- 

 tion on glass surfaces and of the thermal molecular 

 pressure. These difficulties appear to have been 

 overcome in a very satisfactory manner by S. Weber 

 {Kgl. Danske Videnskabernes Selskabs Forhandlinger, \ 

 No. 6, 1915, Copenhagen). The pressure, down to 

 205° absolute, was measured by means of the loss of 

 heat from a hot Wollaston wire, and below this 

 temperature by Knudsen's absolute manometer. It 

 was also checked more roughly by means of a mer- 

 curial manometer with optical contacts, reading to 

 3/x. The residual pressure in the apparatus at 

 143-163° abs. was 0053-0070 dyne per square centi- 

 metre for ice from conductivity water, and about half 

 this for ice prepared inside the apparatus from pure 

 hydrogen and oxygen. After correcting for this 

 residuum, which Is unaccounted for, an extremely 

 good agreement with Nernst's empirical formula was 

 obtained, down to 175° abs. The same number of 

 the above Journal contains the fifth of a series of 

 papers by C. Christiansen on the frictlonal electricity 

 generated by drops of a liquid falling on a platinum 

 plate. The effect Is much greater for solutions of 

 non-electrolytes (mercuric cyanide, triammlnocobalti- 

 nitrite) than for those of electrolytes (mercuric 

 chloride, hexamminocobaltlchloride). 



In a paper entitled "Theory and Practice in the 

 Filtration of Water," read to the Institution of Mech- 

 anical Engineers on April 14, Mr. W. Clemence 

 attempts to prove that the multiple filtration process 

 invented by MM. Puech and Chabal is economically | 

 and hygienically the most efficient process of water 1 

 purification. The process consists of passing the water ; 

 through a series of filters filled with material ranging 

 from coarse gravel in the first to fine sand in the last, '< 

 the greater part of the suspended matter in the water 

 being retained by the earlier elements, so that no 

 film forms on the surface of the final sand filter, the: 

 work of purification being effected by nitrifying organ- 

 isms in the body of the sand, thus differing from other; 

 processes, which depend largely on the straining effect 

 of a surface film formed by natural or artificial means. 

 While making the best case he can for the multiple 

 process — and on the whole a good case — the author 

 scarcely does justice either to mechanical or ordinary 

 slow sand filtration. Most water experts now agree 

 that these latter processes cannot be taken as the 

 "only line of defence" against water-borne disease. > 

 but with an initially "safe" water the improvement 

 in appearance and the removal of oxidlsable matter 

 effected particularly bv mechanical filters are ofter 

 most marked. On' the' other hand, it is claimed thai 

 the multiple process is capable of rendering safe ar 



