144 



NATURE 



[April io, 19 13 



teresting instrument. A curious fact elicited is that 

 there seems to be a slow alteration in the vibration 

 periods of a number of pendulums at the same place, 

 Dehra Dun. Thus all four pendulums used showed 

 thi apparent force of gravity as highest in January, 

 [904, and lowest in November, 1909, with a distinct 

 rise since. No cause can be suggested to account for 

 this variation. An investigation as to how far the 

 Indian observations conform to the requirements of 

 "isostacy" promises interesting results, but is as yet 

 only in a preliminary stage. 



The Alsatian, which is the first of two quadruple- 

 screw turbine steamers being constructed for the Allan 

 Line, was launched from the yard of Messrs. Wm. 

 Beardmore and Co. on March 22. An illustrated 

 account of this vessel, which is 600 ft. long and of 

 gross tonnage about 18,000, appears in Engineering 

 for April 4. A notable feature is the adoption of the 

 cruiser stern, an arrangement which permits of a 

 greater displacement on a given length over-all, with 

 corresponding increase in dead-weight, or, if the dis- 

 placement be not increased, the lines may be fined 

 down, so that the ship is more easily driven, with 

 corresponding reduction in engine power. Further, 

 the fuller water lines aft which are permissible with 

 this type of stern ensure greater stability, especially 

 at the deeper draughts. It is probable also that this 

 form of stern tends to reduce the vibration due to the 

 propellers. Hitherto the Board of Trade has only 

 required a vessel to be capable of remaining afloat 

 with any two adjacent compartments open to the sea. 

 In the Alsatian, the aim of the designers has been to 

 ensure her remaining afloat with four adjacent com- 

 partments open to the sea. 



We have received from Messrs. George Philip and 

 Sons, Ltd., of Fleet Street, London, a specimen of a 

 very handy, light terrestrial globe, 6 in. in diameter, 

 showing by bold blue lines the new routes which will 

 be opened when the Panama Canal is completed. 

 "The Panama Canal Route Globe," as it is named, 

 costs only 2s. 6d. net, and explains easily what a 

 convenience to ocean travel the new canal will be. 



Messrs. Charles Griffin and Co., Ltd., announce 

 the following new books and new editions. In 

 Chemistry : — The Petroleum Technologist's Pocket 

 Book, by Sir Boverton Redwood, Bart., and A. East- 

 lake ; Roberts-Austen : Addresses and Scientific 

 Papers, together with a Record of the Work of Sir 

 William Chandler Roberts-Austen, K.C.B., F.R.S., 

 compiled and edited by S. W. Smith, illustrated; A 

 Manual on the Examination of Fuel, by J. H. Coste 

 and E. R. Andrews, illustrated ; Outlines of Stationery 

 Testing, by H. A. Bromley, illustrated; A Treatise on 

 Petroleum, by Sir Boverton Redwood, Bart., new 

 edition in three volumes, illustrated; A Handbook of 

 Petroleum, by Capt. J. H. Thomson and Sir Boverton 

 Redwood, Bart., new edition, revised throughout and 

 added to by Major A. Cooper-Key and Sir Boverton 

 Redwood, Bart., illustrated; The Synthetic Dyestuffs, 

 and the Intermediate Products from which they are 

 derived, by Dr. J. C. Cain and Dr. J. F. Thorpe, 

 F.R.S., new edition. In Engineering: — Coast 

 NO. 2267, VOL. qi] 



Erosion and Protection, by E. R. Matthews; The 

 Dock and Harbour Engineer's Reference Book, by 

 B. Cunningham; Electricity in Mining, by Siemens 

 Brothers Dynamo Works, Ltd., illustrated; Griffin's 

 New Guide to the Board of Trade Examination for 

 Marine Engineers, by R. A. McMillan, part ii., 

 Elementaries, Verbals and Drawing; A Manual of 

 Petrol Motors and Motor-cars, comprising the Design- 

 ing, Construction, and Working of Petrol Motors, by 

 F. Strickland, new edition. In Geology :— A Text- 

 book of Geology, by Prof. J. Park, illustrated. In 

 Mathematics and Physics :— Electricity and Mag- 

 netism, by Prof. J. H. Poynting, F.R.S., and Sir J. J. 

 Thomson, F.R.S., 2 vols., vol i., illustrated. In 

 Metallurgy :— Autogenous Welding : a Practical Hand- 

 book on the Installation, Working, and Manipulation 

 of Oxy-Acetylene Welding Plant, for the Unition of 

 Metals without Flux or Compression, from the French 

 of R. Granton and P. Rosemberg, translated by D. 

 Richardson,' illustrated ; Practical Assaying, by Prof. 

 James Park, revised and enlarged from the third New 

 Zealand edition; Rand Metallurgical Practice, vol. i., 

 new edition. In Technology : — Engraving for Calico 

 Printing, by W. Blackwood, illustrated; Painters' 

 Colours, Oils, and Varnishes, Hurst's Practical 

 Manual, new edition, revised throughout and re-written 

 by N. Heaton, with a chapter on Varnishes by Dr. 

 M. B. Blackley, illustrated; Painting and Decorating, 

 by W. J. Pearce, new edition, illustrated. 



OUR ASTRONOMICAL COLUMN. 



Nova Geminorum No. 2. — In No. 4638 of -the Astro- 

 nomische Nachrichten three series of magnitude deter- 

 minations of Nova Geminorum No. 2 are published. 

 The first, from the University Observatory, Tokyo, 

 commences with the nova's magnitude 5-1, on March 

 23, and observations were continued until August 17, 

 when its magnitude was 7-89. Both the other sets 

 of observations come from the Observatory of Cracow. 

 The longer list gives the magnitude 3-96 for the nova 

 on March 14 ; by the time the last determination was 

 made, May 19, its light had dimmed to magnitude 

 7-60. 



Light-changes of a Orionis. — A list of 293 mag- 

 nitude determinations of a Orionis, made between 

 November, 1901, and August, 1912, by Mr. C. P. 

 Olivier, of the Leander McCormick Observatory, is 

 given in No. 4637 of the Astronomischc Nachrichten. 

 The table gives, in four columns, the date, Green- 

 wich mean time, determined magnitude, and number 

 of comparison stars used. The values found range 

 from 0-21 (twice) to 1-06 (four times). Under the 

 usual treatment the observations failed to reveal any 

 regularity in the light changes. 



Photographs of Comet Brooks (1911c). — Dr. Luigi 



Taffara (Mem. della Soc. d. Spett. Ital., disp. i a , 



vol. ii., ser. 2 a , p. 11) publishes an account of his 



photographic work on this comet during September, 



1911. His observations were made at the Collurania 



Observatory in Teramo, at the invitation of Dr. 



Cerulli. The instrument employed was a Cooke trip- 



I let of 165 cm. aperture and 1-09 metres focal length. 



I This camera was mounted on the equatorial con- 



I structed by Salmoiraghi (aperture 13-5 cm. and focal 



length 1-75 metres), which was used as a finder. In 



addition to giving a table of positions of the comet 



