March 15, 1906] 



NA TURE 



471 



are fed to cattle or used as a green manure for the betel- 

 vines, and the tender leaves and young pods are served as 

 a curry. 



In the January number of the Bulletin of the Depart- 

 ment of Agriculture, Jamaica, Mr. W. Harris refers the 

 different varieties of yams cultivated in the island to four 

 species, Dioscorea sativa, or negro yam ; Dioscorea alata, 

 or white yam ; Dioscorea cayennensis, the yellow or afou 

 yam ; and Dioscorea trifida, the Indian yam or cush-cush. 

 For the destruction of cotton worm and cassava cater- 

 pillar, where Paris green is likely to injure the foliage, 

 or when it may be washed off by rain, Mr. W. Fawcett 

 recommends a wash of lead arsenate. 



The committee entrusted by the Hawaiian Sugar 

 Planters' Association with the control of the experiment 

 station at Honolulu notifies in its report for the year 

 ending September 50, 1905, that a division of pathology 

 and physiology has been formed under the directorship of 

 Dr. N: A. Cobb, in addition to the division of agriculture 

 and chemistry and a division of entomology. The work 

 of the last named has been chiefly devoted to the study 

 and breeding of insects that prey upon cane leaf-hoppers. 

 Among the bulletins prepared by the agricultural division, 

 the most important presents a review of fertiliser experi- 

 ments extending over eight years. A bulletin on the in- 

 spection and disinfection of cane cuttings is the first publi- 

 cation of the new department. The methods of preparing 

 Bordeaux mixture are discussed, and suggestions are made 

 for treating cuttings on a large scale. 



In' the Engineering and Mining Journal (vol. lxxxi., 

 No. 7) is the first authoritative statement of the discoveries 

 in a new gold field at Manhattan, in Nevada, which is at 

 present attracting much attention. The veins, which 

 appear to be extraordinarily rich in gold, occur in lime- 

 stone in the vicinity of rhyolite. 



The preliminary returns issued by the Home Office show 

 that the production of coal in Great Britain in 1905 

 amounted to 236,111,150 tons, or 3,699,366 tons more than 

 in 1904. The number of persons employed at mines under 

 the Coal Mines Regulation Act was 858,373, or 1-28 per 

 cent, more than in 1904. The production of copper ore 

 was 71 15 tons, that of lead ore 27,482 tons, and that of 

 zinc ore 23,647 tons. Statistics of the production from open 

 workings are not yet available, so that details of the pro- 

 duction of other minerals are incomplete. 



In a paper on the screw propeller controversy published 

 in the Transactions of the Institution of Engineers and 

 Shipbuilders in Scotland (vol. xlix., part iv.), Mr. James 

 Holden endeavours to demonstrate the true action of the 

 propeller, and to show that Rankine's theory is wholly 

 erroneous. He considers that none of those writers who 

 have adopted the Rankine theory, in whole or in part, are 

 able to guide others, either scientifically or practically, in 

 the construction or use of screw propellers. 



The latest addition to technical periodical literature is 

 a bi-monthly journal entitled Concrete and Constructional 

 'Engineering. It has been founded with the object of meet- 

 ling the growing demand for information regarding con- 

 crete and reinforced concrete. The first issue (March) 

 covers 74 octavo pages, and is admirably illustrated. It 

 •contains articles by Lieut. -Colonel J. Winn, on the advent 

 •of the concrete age ; by Mr. W. N. Twelvetrees, on steel 

 ■skeleton construction ; by Mr. C. F. Marsh, on reinforced 

 concrete foundations of buildings ; by Mr. C. H. Desch, on 

 the setting of Portland cement; by Mr. B. H. Thwaite, 

 *o. 1898, VOL. J 5] 



on the preservation of iron and steel against corrosion ; and 

 a digest of recent publications on concrete and construc- 

 tional engineering. 



In the Journal of the Franklin Institute of Philadelphia 

 (vol. clxi.. No. 21 Mr. E. Keller describes and illustrates 

 a number of improved methods and apparatus introduced 

 in the newly equipped assay laboratory of the Anaconda 

 Copper Mining Co. in Baltimore. The chief duty of the 

 laboratory is to determine the values of copper, silver, and 

 gold in crude copper, and the equipment is probably 

 superior to any elsewhere. Stirring and filtering are 

 effected by machines, and in assaying operations every- 

 thing is handled in sets. Much labour has been saved, 

 breakage of expensive glass-ware has been very largely 

 eliminated, and the time of the furnace work and the con- 

 sumption of gas have been much reduced. 



The modern locomotive question is chiefly one of boilers. 

 The great ini rease in the size of boilers and in the pressures 

 carried, which has taken place during the past few years, 

 has necessitated the re-consideration of the principles of 

 design, which had been settled with comparatively small 

 boilers carrying low pressures. The paper on large loco- 

 motive boilers read by Mr. G. J. Churchward before the 

 Institution of Mechanical Engineers on February 16 is 

 therefore opportune. He gives illustrations of various 

 locomotive boilers, and shows how much more heating 

 surface is now provided for a given area of cylinder than 

 was formerly considered necessary. The higher pressures 

 now common have undoubtedly produced much more 

 efficient locomotives, both in respect of hauling power and of 

 coal consumption. The improvement has been very marked 

 with every increment of pressure right up to 227 lb. carried 

 by the new De Glehn compound locomotives of the Great 

 Western Railway. 



The report of the superintendent of the Meteorological 

 Department of Ceylon for the year 1904 shows that 1904 

 must be reckoned as one of the "dry" years; the rain- 

 fall was considerably below the average over the greater 

 portion of the island, especially in the north .and west, 

 where deficiencies of 10 to 15 inches were recorded in 

 several districts. In May, however, the excess of rainfall 

 caused destructive floods ; in the Kelani Valley alone 124 

 square miles were covered, involving great loss of property, 

 the water being higher than at any time since 187 1. The 

 climate varies considerably in different parts of the island ; 

 in the lowlands it is tropical, but in the high parts of the 

 interior it is equal to that of many parts of Europe. The 

 highest shade temperature recorded in 1904 was 99°'8 at 

 Anuradhapura, in May, and the lowest, 28°-2, at Nuwara 

 Eliya, in February ; this is the lowest reading on record. 

 Temperatures exceeding ioo° have been recorded in some 

 years ; the highest on record was i03°-7, at Trincomalee, in 

 May, 1890. 



In the February number of the Bulletin dc la Socidti 

 astronomique de France MM. Flammarion and Loisel 

 publish the annual summary of the climatology of iqo5 

 as recorded at the Juvisy Observatory. It appears that a 

 notable feature of the atmospheric pressure was its extra- 

 ordinary irregularity. With the exception of February, 

 March, and July, the mean monthly temperatui< 

 below the normal. October was the coldest recorded in 

 the neighbourhood of Paris since 1757, excepting the 

 October of 1887. In discussing the solar-radiation record, 

 attention is directed to the abnormal cloudiness of 1905 

 and to its coincidence, in regard to time, with the large 

 number of sun-spots. The writers suggest that the 



