>o 



NATURE 



[December 22, 1910 



quotations and statistics, and give an illuminating account 

 of wlieat-growing in India. 



Passing on to a discussion of experimental work, the 

 authors point out that manurial trials on orthodox lines 

 are of purely academic interest in India. It was no doubt 

 an excellent thing to make them, but their value is limited 

 by the fact that the cultivator cannot usually buy the 

 necessary manures. It is much more to the point to 

 make cultivation trials, seeing that labour is very cheap 

 and the labourer realises the necessity for working the 

 land. But here again intelligent planning is necessary ; if 

 the trials are to serve as demonstrations for the native 

 they must be made with implements he can afford to buy 

 and learn to handle, and which the village blacksmith can 

 repair. A summary is given of the well-known Cawnpore 

 experiments, which show that the nitrogen supply is the 

 limiting factor in normal conditions of moisture and 

 temperature obtaining there. At Nagpur nitrogen was also 

 the most important factor, but the water supply was in this 

 case near the limit. The Punjab irrigation experiments, 

 said to be the best of their kind in India, were made to 

 ascertain the best quantity of water and the best number of 

 waterings. It was found that the native was, like many 

 other irrigation farmers, taking too much water, so that 

 the area under treatment was needlessly curtailed, and the 

 revenue suffered loss. But the authors further point out 

 that over-watering gives rise to mottled grain and to 

 samples uneven in texture, and therefore of low value. 

 This loss in value, of course, falls on the cultivator him- 

 self, and if it could be brought home to him would, no 

 doubt, induce him to take less water. 



The authors then discu»s the factors adversely affecting 

 the production of wheat in India. In order of merit these 

 are climatic extremes, fungi, insects, and vermin. Of the 

 diseases, rusts are the most important, transcending in 

 effect all other diseases put together. The only trust- 

 worthy remedy at present known is to grow rust-resisting 

 varieties. Introduction of such wheats of high repute 

 from abroad proved to be useless ; wheats resistant in 

 Australia succumbed badly in India, and, indeed, were 

 more susceptible than the indigenous kinds, besides ripen- 

 ing too late. It therefore became necessary to raise new 

 varieties from Indian wheats, and this work was begun 

 by the authors in 1905. The first step was to take stock 

 of the native sorts. An ordinary Indian wheat-field con- 

 tains a mixture of several sub-varieties, which had to be 

 isolated. These in turn comprise several types, agri- 

 culturally distinct, though botanically identical, and within 

 each type individual variations occur. Selection w^s 

 carried on, not on the old mass-selection lines, but by 

 isolating single plants and studying their progeny in 

 succeeding generations. The separation of forms and of 

 pure lines has been successfully accomplished, and already 

 several wheats have been obtained which are of much 

 greater value than the mixtures at present in cultivation. 

 Indeed, five of the Pusa selections have been shown by 

 milling and baking tests to be in the same class with the 

 Canadian spring wheats,- the strongest and most valuable 

 on the market. When the botanical survey was well on 

 to completion it was possible to hybridise. This work is 

 now in hand, and it is to be hoped that Mr. and Mrs. 

 Howard will be able to carry the hybridisation on for the 

 necessary length of time, so that the full benefit of their 

 survey and selection work may be obtained. 



A list of the botanical varieties of wheat found in India 

 is then given, and for certain provinces the agricultural 

 varieties as well. This survey is still in progress. 



Throughout the book and the papers which the authors 

 have issued the various wheat problems of India are 

 handled in a masterly way. The record of work done 

 reflects the highest credit on the authors, and is full of 

 promise for the future of Indian agriculture. 



THE REDUCTION OF ROLLING IN SHIPS. 



"D EFERENCE is made in Engineering for December 16 

 ■^^ to a paper by Mr. H. Frahm at the November meet- 

 ing of the Schiffbautechnische Gesellschaft, in which the 

 author describes his apparatus for reduction of rolling in 

 ships. In this apparatus two water tanks are disposed on 

 opposite sides of the centre line of the ship near the shell, 

 and are connected below bv a water conduit and above 



NO. 2147, VOL- 85] 



by an air conduit ; a throttle valve is inserted in the latter. 

 The water tanks are filled partly with water, which mav 

 oscillate in the closed circuit formed by the conduits. If 

 the throttle valve is closed oscillation is practically pre- 

 vented ; with the valve full open the oscillations are un- 

 obstructed, excepting that free waves cannot arise. 



The principle on which the device is based is that ,1 

 series of wave-impulses will cause the ship to oscill.i' 

 about its longitudinal axis; these oscillations will becon; 

 pronounced when the period of the wav<3s agrees with tb.n 

 of the natural vibration of the ship. These differ in phast 

 by 90°, i.e. the maximum deflection of the ship from th'' 

 vertical will occur a quarter period after the wave h;i^ 

 been at its maximum inclination to the ship. The sauT 

 applies to the oscillations of the ship and to those of th 

 water column in the tanks, which rises and falls so tli; 

 the two oscillation periods are equal, provided the walri 

 has the proper mass. In this case the oscillations of the 

 water column will lag a quarter period behind those <>^ 

 the ship, and hence half a period behind the period ■ 

 the waves, and the two turning moments acting on tli 

 ship will therefore oppose one another. This is an appli- 

 cation of the principle of resonance. 



Mr. Frahm 's apparatus is beyond the mere experimental 

 stage. The oil-tank boat W83 of the German Navy, ^^i> 

 tons displacement, is a very stiff boat, with a high natural 

 vibration period of 10-75 per minute. In dock the deflec- 

 tions from the perpendicular were reduced from 10° to 

 2° by twelve oscillations when the tanks were cut out, 

 and by two oscillations with the tanks in action. At sra 

 the amplitude of rolling was diminished to one-thin! 

 Two steamers of the Hamburg-.^merica Line — t! 

 ypirango and Corcovado — of 12,600 tons displacement, 

 have been fitted with the anti-rolling tanks. The formi-r 

 was a notorious roller. Both are now regarded as steady 



j boats; the tanks reduce rolling 11° (on either side) to 

 25° maximum. Messrs. Blohm and Voss are designing 



I anti-rolling tanks for the new passenger steamer of 55,000 

 tons which they are now building for the Hamburg- 

 America Line. The paper in itself is very interesting, and 

 is doubly so in view of statements made recently in the 

 case of the loss of the British steamer Waratah. 



ARGENTINE METEOROLOGICAL RESEARCH.^ 



"T^HE services rendered to meteorology by Dr. W. S. 

 Bruce in founding the meteorological observatory at 

 Scotia Bay, South Orkneys, in 1903, are brought into 

 forcible evidence by the publication of successive year<' 

 observations. Through the exertions of Dr. Escalant 

 Minister of Agriculture, and the enthusiasm of Mr. VV. (■. 

 Davis, the Argentine Meteorological Office was enabled to 

 take over the observatory from the Scottish National 

 .Antarctic Expedition, and has maintained it ever since. 

 It must be remembered that this is the only permanent 

 meteorological observatory in Antarctic regions. Th° 

 observations for 1904, with an introduction by Mr. R. ( 

 Mossman, are now published, though the title-page i~ 

 dated 1905. The observations of following years seem not 

 yet to have appeared, but they are briefly summarised in a 

 m.ost interesting and useful outline- by Mr. W. G. Davis 

 on the chmate of the Argentine Republic. It may be 

 mentioned, also, that a discussion by Mr. Mossman of 

 each successive year's observations has appeared year b\ 

 year in the Scottish Geographical Magazine. The tardv 

 appearance of the 1904 volume detracts somewhat from i' 

 interest in view of our knowledge of the six later year-, 

 but we understand that circumstances beyond the control 

 of the Meteorological Office alone delayed the publication. 



Previous io the expedition of the Scotia it was supposed 

 that, from their latitude, the South Orkneys would enjoy 

 an oceanic climate. Actually, however, these conditions 

 only obtain for four months, while for the rest of the year 

 the conditions are continental. In exceptional years either 

 of these states of climate may be prolonged at the expense 

 of the other. The climate largely depends on the distri- 

 bution of ice in the Weddell Sea. The average mean 



1 Anales de la Oficina Meteoroldeica Argentina.^ Tomo xvi.,_ O''^'" 

 vaciones de las Islas Orcadas en el Ano 1904. Text in both Spanish and 

 English. (Buenos Aires, 1905.) 



" Climate of the Argentine Republic." By W. G. Davis. (Buenos Aires : 

 Department of Agriculture, igio.) 



