550 



NATURE 



[August 31, 1916 



leathery turtle and the loggerhead have no great com- 

 mercial value, but their eggs are taken in large num- 

 bers. The green turtle, however, for its meat, and 

 the hawksbill for the sake of irs horny shields, which 

 form the " tortoiseshell " of commerce, are subjected 

 to a heavy toll, young and adults alike being taken. 

 The green turtle is happily enabled to lessen the 

 strain of this persecution in that it lays its eggs so 

 near the margin of the sea that all traces of their 

 whereabouts are obliterated by the wash of the tide. 

 Since the Danish West Indies have recently been 

 purchased by the United States it is to be hoped that 

 stringent protective measures will speedily be devised 

 and enforced, for it is evident that otherwise the 

 extermination of these colonies is within measurable 

 distance. 



In a " Note on the Economic Uses of Rosha Grass, 

 Cymbopogon martini, Stapf," published in the 

 "Indian Forest Records," Mr. R. S. Pearson points 

 out that this grass exists in two forms, known to 

 the natives as "Motia" and "Sofia." The two forms 

 appear to differ morphologically only in the fact that 

 in the Motia grass the leaf blade makes a wider ang^le 

 with the culm than is the case in the Sofia grass. The 

 distribution of the two forms also differs considerably, 

 Motia growing in isolated clumps on bare hot slopes, 

 whilst Sofia occurs on low ridges and in shady nullahs 

 often as a dense crop. The chief difference between 

 the two forms lies, however, in the characters of the 

 ■essential oils they contain, Motia grass yielding 

 "palmarosa oil," containing as much as 90 per cent, 

 ■of free and combined geraniol, whilst the Sofia form 

 yields the so-called "ginger grass oil," containing only 

 about half as much geraniol. The note states that 

 experimental cultivation of the two forms has now 

 "been undertaken at Dehra Dun by Mr. R. S. Hole 

 with the view of determining their botanical relation- 

 ship. 



The Journal of the Society of Siberian Engineers 

 •(Tomsk, March, 19 16) directs attention to the back- 

 ward state of Russian agriculture in the matter of 

 the employment of artificial fertilisers, and emphasises 

 the vital necessity of reform in this direction. In 

 contrast with other countries it is pointed out, among 

 other things, that Russia does not yet possess a single 

 factory for utilising atmospheric nitrogen in the pre- 

 paration of fertilisers, though she has ample supplies 

 of raw material and water-power. 



An interesting instance of untutored native ability 

 is reported from Tomsk in the Journal of the Society 

 of Siberian Engineers (January, 1916). In the 

 Ochansky district a self-taught farm labourer, Kazy- 

 mov by name, working on the model of the American 

 machines, made a horse reaper of a very simple type, 

 weighing only 400 lb., and capable of being worked 

 easily by one horse. The local council, on hearing of 

 this, considered it sufficiently important to warrant 

 official investigation, and appointed a special com- 

 mittee for that purpose. After inspecting the machine 

 the committee came to the conclusion that although 

 of very primitive construction R is suitable for the 

 work and might with some trifling technical altera- 

 tions be widely adopted, seeing that it is superior to 

 the factory-made machine in lightness and in suit- 

 ability for the small "one horse" farmer. The price 

 of the Kazymov reaper may be estimated approximately 

 at 81. 



The distribution of cyclonic precipitation in Japan 

 is the subject of a paper by Messrs. Terada, Yokota, and 

 Otuki in the Journal of the College of Science, Tokyo, 

 vol. xxxvii, art. 4. The paper is partly a statistical 

 Investigation of the influence of land and water in 



NO. 2444, VOL. 97] 



modifying the rainfall from 1905 to 1915, but contains 

 also an attempt to analyse the factors that determine 

 the unsymmetrical distribution of precipitation. These 

 the authors group as (i) thermal and planetary, which 

 depend on latitude ; (2) thermal and geographical, 

 which depend on the prevalence of sea or land; (3) 

 hydrodynamical and topographical, caused by the 

 ascending air current. The whole discussion is some- 

 what hypothetical, and would be more profitable were 

 the data more numerous. 



The eruption of Mauno Loa which took place last 

 May is briefly described by Mr. H. O. Wood in the 

 Weekly Bulletin of the Hawaiian Volcano Observa- 

 tory (vol. iv.. No. 5, igi6). Fume-columns were first 

 noticed at 7 a.m. (or 5.30 p.m., G.M.T.) on May 19. 

 At 8 a.m. the crown of the cloud had reached a height 

 of not less than 20,000 ft. above the mountain profile, 

 but by noon the rush of fumes had almost ceased. A 

 small amount of lava was ejected at the time of this 

 outburst. Shortly after 11 p.m. on May 21 another 

 and greater flow began from a source lower down 

 the slope, at an altitude of about 7000 ft. on the south- 

 south-west slope of the mountain. Hundreds of very 

 slight tremors were registered during these days at the 

 Volcano Observatory on the north-eastern slope of 

 Kilauea, though only three or four were strong enough 

 to be felt in the .neighbourhood of the observatory. 



The August number of the Proceedings of the 

 Physical Society of London completes vol. xxviii. 

 The seven papers included in it cover seventy 

 pages, and are of exceptional interest. Mr. G. D. 

 West deals with the effects of the residual gas in 

 measurements at low gas pressures of the pressure 

 due to radiation. Miss Humphrey and Dr. Hatschek 

 show that the viscosity of a liquid having small solid 

 particles in suspension increases more rapidly than the 

 aggregate volume of the suspended matter, and depends 

 on the rate of shear. Capt. Phillips describes a 

 form of mercury jet interrupter by means of which 

 he has investigated the conditions which determine-the 

 smooth working of the interrupter. Dr. P. E. Shaw 

 and Mr. C. Hayes describe a magnetometer of the 

 torsion balance type a million times as sensitive as any 

 previous instrument. Dr. S. W. J. Smith discusses 

 the relation between the original migration experi- 

 ments of Hittorf and the recent ones of Mrs. Griffiths, 

 which have given somewhat different results. Dr. 

 Allen shows that Ratnowsky's recent theory of the 

 process of fusion is incorrect, and Dr. Chatley describes 

 the present position of the attempts to explain cohesion 

 and shows that it must be regarded as the difference 

 between the attractive and repulsive forces between 

 molecules. 



The sixth annual report of the Road Board has 

 just been issued. The amount of new work sanctioned 

 has been reduced greatly, but the Board has con- ■ 

 tinued to supervise the construction and maintenance 

 of new roads required for military purposes, and this | 

 work has extended considerably. An account of the | 

 method of testing surfaces by rotary machine is in- } 

 eluded. The machine consists of a revolving frame , 

 supported on wheels running on a circular test path 

 at any desired speed — not exceeding seven miles an : 

 hour for steel tyres. Each of the eight wheels is ' 

 independently driven by electromotors. The usual 

 load per inch width of tyre has been about 470 lb. 

 Since wetted surfaces can be tested to destruction 

 sooner than dry surfaces, the wet test has become the 

 standard of comparison. A room, temperature ap- _ 

 proaching that of summer has generally been main- | 

 tained^ since bituminous materials soften and show 

 the least resistance to deformation during the summer 

 months. After the test track has been laid, the 



