5° 



NA TURE 



[March i i, 1909 



In which it should be set forth that in taking measure- 

 ments under the arm the thermometers should be allowed 

 to lie for five minutes before the reading is taken. 



Messrs. Scheel and Heuse have published in the 

 February number of the Zeitschrift jiir Instrumentenkunde 

 the results of some investigations undertaken by them on 

 :the methods of producing high vacua. The tests were 

 ■carried out on the Gaede pump, the Toepler pump, Reden 

 and Rosenthal's mercury pump, and on charcoal in liquid 

 air used in connection with the air pump. The resultant 

 pressures were measured by the McLeod vacuum gauge, 

 the authors having found {Verhandlungen der deutschen 

 pbysikalischen Gcsclhchaft, vol. xi., p. i) that this method 

 lould be applied for the measurement of the lowest 

 pressures. The most important result was that obtained 

 by employing charcoal prepared from cocoa-nut shell, and 

 using this charcoal, in liquid air, in conjunction with an 

 air pump (Gaede's), the initial pressure of o-oo6 millimetre 

 Tieing derived from the pump. A vacuum of o-ooooi milli- 

 inetre was obtained and kept up for some time by this 

 method. Complete tables of readings, and a full descrip- 

 tion of the experiments, are given in the article. 



An interesting report of trials on a complete steam plant 

 at the Greenvale Mill, Littleborough, near Manchester, is 

 ^iven in Engineering of February 26. The trials were 

 made under the direction of Mr. G. B. Storie, consulting 

 engineer, of Rochdale, and his report is of special interest 

 ■on account of the very full results given. The plant 

 includes a Brush-Parsons parallel-flow steam turbine 

 •developing 500 kilowatts at 3000 revolutions per minute 

 and 200 lb. per square inch steam pressure. Mr. Storie 

 finds its thermal efficiency at gi-S per cent, of the rated 

 power to be i8'27 per cent., the efficiency ratio by com- 

 parison with the Rankine cycle being 0-579. It '^ unusual 

 to find a report on a steam turbine containing information 

 regarding the pressure, temperature, and degree of super- 

 Iicat of the steam at the end of each stage of the expansion, 

 and it would be very useful if other experimenters would 

 take Mr. Storie's report as an example in this respect. 

 There has been a tendency to withhold such information 

 in the past. Special attention may be directed to the 

 following table of results showing the importance of main- 

 taining a good vacuum with steam-turbine plants : — ■ 



A PAPER on some recent grain-handling and storing 

 appliances at the Millwall Docks, by Mr. Magnus Mowat, 

 read before the Institution of Civil Engineers on March 2, 

 lontained some interesting facts about grain elevators. 

 The installation now provides for the discharge and weigh- 

 '"§ of 55° tons of grain per hour ex ship, and for its 

 tielivery either partly or wholly into granary, silo, or 

 l^arge. The elevators which come in contact with the 

 ship's hold are of the pneumatic or suction type. The 

 granary and silo elevators are of the bucket type, and, like 

 the band-convpyers, are of two-ply woven cotton, impreg- 

 nated with rubber. These bands have a total length of 

 NO. 2054, VOL. 80] 



25 miles; they are electrically driven. In the waterway 

 there is a dolphin, alongside which the ship is moored. 

 This is a wooden jetty of greenheart tiinber, 350 feet by- 

 24 feet, placed 50 feet clear of and parallel with the quay. 

 On its deck are four suction elevators, each of 75 tons 

 per hour capacity, corresponding with the respective holds 

 of the ship. The machinery within the dolphin includes 

 four pairs of exhauster pumps, each 46 inches diameter 

 by 60 inches stroke, which maintain in the grain-receivers 

 on the top of the towers a partial vacuum of 7 inches to 

 10 inches of mercury. Flexible pipes connect the receiver 

 with the ship's hold, and the grain is elevated to a height 

 of 80 feet by the inrushing air, the proportion of air being 

 controlled by nozzles with adjustable sleeves. The grain 

 separates itself from the air in the receiver, and automatic- 

 ally discharges through " tippers " at the bottom of the 

 chamber into hoppers which feed the weighing machines. 

 These deliver through steel shoots into barges, or connect 

 with the quay by band-conveyers on bridges spanning the 

 intervening water-space. The band-conveyers within the 

 granary and subways under the quay are endless, and are 

 supported at 6-fect intervals by steel rollers on cast-iron 

 standards, tied longitudinally by steel angles on each side; 

 their speed is 552 feet per minute. The bands and 

 elevators form a series for mechanically conveying the 

 grain from the dolphin elevator to the roof of the granary, 

 from which it is distributed to the various floors by gravity 

 through pipes provided with sleeves and doors for housing 

 and delivery to or from any section. 



We have received from Messrs. John Wheldon and Co., 

 of Great Queen Street, London, W.C., a copy of their 

 latest catalogue of geological works, containing particulars 

 of 1761 publications they have on sale. The books con- 

 cerned include selections from the libraries of the late 

 Prof. Ramsay, Dr. R. Hunt, Prof. J. Percy, Prof. Phillips, 

 Mr. William Topley, and Dr. Flight. 



Mr. Francis Hodgson has published the sixth volume 

 of the second series of the Proceedings of the London 

 Mathematical Society. The record deals with meetings of 

 the society held from November, 1907, to June, 1908, and 

 the papers read on these occasions, short abstracts of 

 which have appeared already among our reports of socie- 

 ties and academies. The volume also contains obituary 

 notices of the late Lord Kelvin and Mr. C. Taylor. 



OUR ASTRONOMICAL COLUMN. 



Anomalous Refraction and Spectroheliograph 

 Results. — Having spent some time, in August, 1907, at 

 the Mount Wilson Observatory, and having employed the 

 splendid equipment there in a number of experiments. 

 Prof. Julius has derived further confirmation of his theory 

 that some of the phenomena seen on various spectrohelio- 

 grams are, at least in part, due to the anomalous refrac- 

 tion which waves from the vicinity of absorption lines 

 must suffer when passing through an absorbing medium 

 of varying densities. The. experiments and the results 

 obtained are described and discussed in No. 5, vol. xxviii., 

 of the Astrophysical Journal. 



By selecting lines at different distances from the sodium, 

 D, lines, and passing the rays through a tube containing 

 sodium vapour, in which the density gradients could be 

 controlled, Prof. Julius was able to obtain photographs 

 showing the effects of anomalous refraction, and he shows 

 that equivalent conditions probably exist in the solar atmo- 

 spheres. Should the further work which is to be carried 

 out on these lines prove confirmatory, it will no longer be 

 necessary to explain " dark " and " bright " flocculi by the 

 assumption of very marked differences in the absorbing 

 and emitting conditions of a certain gas or vapour in con- 

 tiguous regions on the sim, for the anomalous refraction 



