September 12, 1918 



NATURE 



3 1 



" In Prof. Birkeland's view, "a nebulous 

 ring round the earth will alone never give anj 



!. uiation of the zodiacal lij 



The water supply to the town of Hobart, Tasm a 

 was ili.' subject 'if an article in the Engineei of Sep- 

 1 6. The reservoir has a capacity of 207 million 

 gallons, and the dam is an interesting instance of 



gravity wings with an intervening arch section. 

 The win^s are 2934 ft. and 203J ft. long respectively, 

 in straight lengths, ami the arch is 232I ft. long, with 



lius of 200 ft. The wings and the arch are not 

 actuallv connected; a 6 in. by 6 in. bitumen joint, 

 with sheet-lead faces, forms a watertight key from 

 ground-level to the top of the dam. The maximum 

 depth from the summit of the arch section in the 

 centre r. » the Foundation is mi ft. The greatest depth 

 of water in the reservoir is q; ft., and the surface- 

 level is 905 ft. above sea-level. The dam is constructed 

 hkI the arched portion is reinforced with 

 iron rails, both vertically and horizontally. The thick- 

 it the top is 6 ft., and at the bottom 

 54 ft. An unforeseen fissure in the foundation neces- 

 sitated the linking of a shaft to a depth of 185 ft. 

 below the ground-level ; this was refilled with con 



L'Adrophile for May gives a description of the 

 Vincent multiplex compass, which, it is claimed, corn- 

 in on.' small case all instruments required by 

 the aviator, the navigator, and the explorer for the 

 determination of magnetic declination and for the 

 solution of astronomical, geodetic, and topographical 

 • problems required for determining position and direct- 

 ing the course of travel. It is also claimed that this 

 compass provides a means of steering craft overseas 

 with .1 precision hitherto unknown. The compass is 

 ded with a reference line or directrix, which may 

 be rotated, .1 movable index card with sights for the 

 -nrement of angles and azimuths, and a style for 

 ■ 1 11 1 i 1 in of time problems. The whole compass is 

 suspended on gimbals inside a box, which is pivoted 

 on a slab. The box carries on one of its faces a 

 needle and a dial, and on its bottom a second needle, 

 which moves over degree graduations on the slab. 

 The method of using the compass is explained. 



A French Electrotechnical Commission has just 

 published, in English and French, the results of an 

 investigation on aluminium. The mechanical and 

 physical tests give the density, coefficient of expan- 

 sion, breaking stress, and elongation. Chemical ana- 

 were also made. According to the Revue 



'.i/c de I'Electricite" for June 8, the electrical 

 measurements were made at the Laboratoire central 

 d'Electriciti, and include resistivity and temperature- 



1 i. in of commercial aluminium. A table is 

 in which '1 ■ lor three different samples of 



aluminium, containing slightly different amounts of 

 impurities, are set out. 



Dr. P. Lindner, of Charlottenburg, has taken out 

 a German patent (Chemiker-Zeitung, June 29) for 

 i;ny fat from low I imal life. By popu- 



lating suitable waste material with these minute forms 

 he obtains material from which fat may be ex- 

 il \s examples he mentions decaying mush- 

 rooms and non-edible fungi, putrefying meat, gutter 

 refuse, etc., grass and spoilt hay, masses of dead li 

 infested « iih plant-lice, and stale yeast. Dr. Lindnei 

 further states that certain materials may be inoculat. d 

 with the germs of bacteria or micro-fungi and culti- 

 vated. The mass of prepared material is triturated 

 mixed with water, then heated, and the fat 

 skimmed off; or it may be 'recovered chemicall 

 treating the triturated mass with a solvent. 

 NO. 2550, VOL. I02] 



\\'i learn from a no 1 1 the Journal of the Society 



of Chemical Industn for \u : 5 thai the giant 



i thi Pacifii ( oasi now being utilised on a 



I irge scale for thi produ. tic f both potash and 



acetone. The works, mated at Potash, 



mar San Diego, Califoi thirty acres of 



ground and give employment n. Acetone, 



rather than potassium compound , h - I. .-come the 

 chief product; it is required foi hi British authori- 

 \m\ is of excellent quality. Among the sub- 

 sidiai red are ethyl propionate and 



ethyl butyrate, which are now being obtained on a 

 scale never before approached. This, compounds 

 serve .is solvents, and arc especially valuable just now 

 is substitutes for amvl acetate, on account of the 

 necessity for conserving acetates. The quantit; of 

 kelp cut last year was about 24,000 tons a month. 



The Cambridge Scientific Instrument Co., Ltd., has 

 issued a new list (No. 1^7) dialing with the Cam- 

 bridge microscope lathe-attachment. This is a device 

 recently placed on the market to aid in tool-setting 

 for the production of exact and interchangeable 

 screw-threads. The attachment consists of a com- 

 pound microscope fitted with an eyepiece that is 

 capable of being focussed on a diaphragm ruled with 

 two fine lines representing the thread-angle of the 

 tool to be used, and with a third line equally inclined 

 to them. When the third line is set parallel to the 

 axis of the cylinder to be threaded, the two inter- 

 secting lines represent accurately the position in which 

 the tool must be set. The device is rigidly fixed to 

 the slide-rest, consequently both move together. The 

 standard diaphragm is engraved with a 55 angle. 

 The inaccuracy of tool-setting by this method should 

 not exceed o° %'. The list describes also the Cam- 

 bridge alignment tester for ensuring the correct align- 

 ment of machine-tool beds within close limits. In 

 this instrument a microscope fitted with a micrometer 

 eyepiece is used to view a fine wire stretched along 

 the length of the bed. One division of the micro- 

 meter scale corresponds with 1/2000", so that high 

 accuracy is obtainable. 



An outstanding feature of Catalogue No. 175 just 

 issued by Messrs. W. Heffer and Sons, Ltd., Cam- 

 bridge, is a number of books printed at special presses 

 such as the Kelmscott, Doves, Riccardi, and others. 

 Sections appealing more particularly to readers of a 

 iournal such as Nature are devoted to agriculture, 

 botany, geology, mathematics, phvsics and chemistry, 

 zoology and biology, physiology, anatomy, and 

 medicine. 



The following works are in the press for publica- 

 tion bv the Carnegie Institution of Washington : — 

 "Human Vitality I fticiency under Prolonged 



Restricted Diet," b\ Benedict, Miles, Roth, and 

 S m i t i 1: ■ \ Bii Study of Basal Metabolism in 



Men. Women, and Children," by J. A. Harris and 

 F. G. Benedict; "Effect of Alcohol on Psycho- 

 physiologic il I unctions," bv W. R. Miles. 



Messrs, Charles Griffin and Co., Ltd.. will pub- 

 lish shortly "A Treatise on British Mineral Oil." by 

 E. K. Cunningham Craig. A. G. V. Berry, Dr. A. E. 

 Dunstan, Dr. Mollwo Perkin, and A. Campbell. The 

 work will contain a foreword by Sir Boverton Red- 

 Bart., and be edited by J. A. Green. 



The article bv Dr. Janus Ward on "Psychology" in 

 Encyclopaedia Britannica" has been expanded by 

 lUthor, and will be published shortly in book foim 

 the Cambridge University P 



