November i8, 1909] 



NA TURE 



77 



contains descriptions of the Cliarleston (iSSb), tlie Cali- 

 fornia (igo6), the Kingston (1907), and the Messina (1908) 

 earthquakes. The second, by Mr. W. H. Hobbs, deals 

 with the evolution and outlook of seismic geology, and 

 advocates two lines of advance : — first, to make practical 

 use of the knowledge already gained, and second, to 

 refine our instruments until we are capable of forecasting 

 the time, place, and severity of the next earthquake. He 

 points out the importance, as a means of forecasting, of 

 tlie principle of immunity from shock for a long period 

 of a region which has just experienced one, and suggests 

 that more refined instruments may show that slight tremors 

 precede all shocks. \ third paper, by Mr. H. F. Reid, 

 urges the United States Government to found a seismo- 

 logical bureau for the study of earthquakes, particulaily 

 in the United States. 



Marine steam turbines show generally a lower efficiency 

 as compared with corresponding land turbines on account 

 of the compromise which has to be made regarding speeds 

 of revolution. TWSs is owing to the fact that the pro- 

 peller has best efficiency at comparatively low speeds, 

 while the turbine gives best results at high speeds. In 

 Engineering for November 5 is described one of the several 

 methods which have been tried for securing a reduction 

 of speed from the turbine to the propeller, thus enabling 

 both to be worked at their best speeds. The arrangement 

 is due to Dr. Fottinger, of the Vulcan Company, of 

 Stettin, and consists of a differential water-turbine trans- 

 mitter in which the primary water-wheel is driven by the 

 steam-turbine shaft, and transmits water with a certain 

 velocity through guide blades or directly to a secondary 

 wheel or wheels mounted on the secondary or propeller 

 shaft In the same axial plane. Transmission ratios of 

 from 3/1 up to 12/ 1 can be provided, and reversal can be 



s obtained by means of a reversing water-turbine transmitter 



i of somewhat similar design on the same shafts. With an 

 experimental installation at the works in which the primary 



• shaft runs at 1600 revolutions per minute and the pro- 



p.ller shaft at about 270 ahead, reversal to 250 revolutions 



rri can be obtained in nineteen seconds. The efficiency 



I i\ver transmission rises rapidly to 78 per cent, at 600 



ilutions per minute of the primary shaft, and remains 



mnstant at 83 per cent, at 1250 revolutions. This installa- 



LiMii has a transmission ratio of 4-5 to i. The Vulcan 



Company have built a special steamer for trials with this 



I arrangement, and it will also be probably tried on war- 



■ ships. The arrangement seems to be valuable and likely 



I to come into extensive use. 



I We have received from Mr. Bernard Ouaritch, 11 

 Grafton Street, New Bond Street, London, a copy of his 

 current issue of rare and valuable books now offered for 

 sale. The list includes many interesting volumes con- 

 corned with America and .'\ustralasia. 



Messrs. Longmans, Green .and Co. will publish in a 

 few days " Beasts and Men : being Carl Hagenbeck's 

 Experiences for Half a Century among Wild Animals," an 

 abridged translation by H. S. R. Elliot and A. G. Thacker, 

 with an introduction by Dr. P. Chalmers Mitchell. Carl 

 Hagenbeck is the founder of the famous Zoological Park 

 at Stellingen, near Hamburg. 



Reference has been made before in these columns to 

 the convenience of the circulating library of Mr. H. K. 

 Lewis, Gower Street, London, to students of science and 

 others. The most recent list of new books and new 

 editions added to the library during July, August, and 

 September of the present year shows that great pains 

 are being taken to keep the library complete and up to 

 date. 



NO. 2090, VOL. 82] 



The Cambridge University Press announces as in the 

 press " Mathematical and Physical Papers," by the late 

 Lord Kelvin, vol. iv., hydrodynamics, containing vortex 

 motion, tides, and waves on water, collected and arranged 

 by Sir J. Larmor, secretary of the Royal Society. The 

 same publishers have in preparation " Lord Kelvin : 

 Scientific Remains," including excerpts from early diaries 

 and from his scientific correspondence, together with a 

 reprint of the historical account of his scientific career 

 prepared for the obituary notices of the Royal Society. 

 This work is also by Sir J. Larmor. 



OUR ASTRONOMICAL COLUMN. 



.\ Brilliant Meteor. — A magnificent meteor was 

 observed, at iih. sgm., at the Solar Physics Observatory, 

 South Kensington, on November 15. The observed path 

 was from about 114^°, -1-272° to 873°, +6°, i.e. froni 

 immediately below Pollux to immediately below Betelgeuse, 

 the path being nearly horizontal. 



The meteor was very bright, e.xhibited striking red and 

 greenish tints, and travelled with a medium velocity. It 

 did not e.xplode, but the large bright head simply faded 

 away, leaving a definite trail, which endured for some 

 two or three seconds. 



Elements of Halley's Comst. — The following five 

 elements of Halley's comet are those calculated bv Mr. 

 P. H. Cowell, F.R.S., and Mr. A. C. D. Crommelin, from 

 the perturbations since 1835 : — 



Longitude of ascending node 57 16 12 



Node to perihelion lii 42 16 



Inclination of orbit 162 12 42 



Semi-major axis of ellipse 1794527 



Eccentricity o'96728l 



The above elements have not yet been re-determined fron-a 

 recent observations. 



The predicted date of perihelion passage was igia 

 April 166. 



The observed positions in 1909 September and Octobm 

 can be satisfied, both in right ascension and declination,, 

 by altering the date of perihelion passage to 1910 April 19 7 

 and retaining the predicted values of the other elements. 



Recent Observations of Mars.^ — In No. 4367 of the 

 .istronomische Nachrichten M. Jonckheere gives 24-325" 

 as the mean diameter of Mars from several observations 

 near opposition ; at unit distance this would be 9-533", 

 which means that if the diameter of the earth be taken 

 as 10, that of Mars is 0-540. The observed flattening of 

 the polar diameter was i : 270-8. A list of nine probably 

 new canals is given, names being proposed for six of thein 

 which are certainly novel. 



In No. 4368 of the same journal M. Jonckheere gives 

 two drawings, made on September 30, iih. 30m. (long. 

 210°), and October 5, loh. lom. (long. 145°), respectively. 

 On the former date a number of " lands " and thirty-four 

 canals, four probably new, were seen, and on the latter 

 date forty-nine canals, six probably new, and seven 

 " lands " were recorded. Among the latter were the two 

 new ones, Stella, near the polar cap, and Thaumas, in 

 the Aonius Sinus. 



No. 4367 also contains a note, by M. Jarry Desloges, 

 recording the observation and disappearance of a- 

 terminator projection in the region of Daedalia, variations 

 in the Lacus Solis, the Aurorse Sinus and Deucalionis 

 Regio, and the discovery of two new canals. 



A paper by M. Desloges also appears in No. 17 of the 

 Comptes rendus (October 26), in which the author divides 

 the canaliform markings into three types : — (i) broad 

 greyish bands ; (2) lines of medium breadth, very dark, and 

 with definite edges ; (3) fine lines near the limit of visibility. 

 He suspects that some features of the first type have, at 

 times, been resolved into finer details, whilst among those 

 of the second type changes have undoubtedly taken place. 

 The finer markings, type 3, appear to have become greatly 

 augmented in number. His collaborators, MM. Fournier, 

 saw Araxes, type i, single, then double, and finally 

 triple, but M. Desloges himself has never been certain of 

 seeing a canal doubled. Two charts given in the paper 



