May 2 1, 1896] 



NATURE 



\Ve notice that no denomination is given to the weights of seeds 

 in the table on p. 47, though pounds, of course, are intended. 



Messrs. Macmii.lax and Co. have made arrangements for 

 the issue in New York and London of a " Dictionary of 

 Philosophy and I'sychology," under the editorial supervision of 

 Professor Baldwin of Princeton University. All the matter in 

 the Dictionary will be original and signed, and the several 

 departments will be entrusted to men most competent to deal 

 with them. 



WKiriNr, with reference to the diagram published in Nature 

 of February 27 (vol. liii. p. 404), to illustrate the movements of 

 the terrestrial pole determined by Prof. Albrech, Mr. T. W. 

 Kingsmill points out that the irregular variations in the curve are 

 apparently coincident with remarkable seismic disturbances. 

 He therefore suggests that there is a connection between move- 

 ments of the earth's axis and unusual seismic activity. 



We have received two more of the valuable publications of 

 the Geological Survey of Canada, forming Parts B and M of 

 Annual Report, vol. vii. The first of these is a Report on the 

 Kamloops map-sheet of British Columbia, by Dr. G. M. Dawson. 

 It is accompanied by two maps of the area, one strictly geo- 

 logical, the other glacial and economic, and the Report itself 

 contains a number of reproductions of photographs of the 

 district. The rocks of the area range from Cambrian to Tertiary 

 and later, and are described at length ; while topographical, 

 meteorological, and mineralogical observations are also recorded. 

 The whole volume consists of over 400 pages. The second is a 

 Report by Mr. R. Chalmers on the surface geology of parts of 

 New Brunswick, Nova Scotia, and Prince Edward Island. 

 Besides minor matters of local interest, it includes discussions on 

 the origin of the Bay of Fundy depression, the glacial stria; of 

 the district, and the destruction of the forests. Several maps ac- 

 company the Report, and a photograph of tlie famous tidal 

 bore in the Petitcodiac River, Bay of Fundy, deserves special 

 mention. 



True it is that at the Royal Victoria Hall, in Waterloo 

 Bridge Road, music and mummery occupy a larger share of 

 attention than lectures on scientific subjects. South London 

 audiences have but a mere penchant for the generous new wine 

 of science ; they reserve their capacities for the variety enter- 

 tainments. But though the audiences on Tuesday evenings, 

 when scientific discourses are delivered, are very much smaller 

 than on the evenings when a lighter vein predominates, they 

 listen in a way which shows that, they appreciate the fare pro- 

 vided for them. And it is satisfactory to know that most of the 

 lecturers are in the front rank of scientific investigators, for this 

 fact may be taken as a guarantee that sound information is 

 imparted. The list of lecturers and subjects given in the report 

 on the work of the Hall during 1895 is most creditable to the 

 energy of Miss Cons, the Secretary, and to the generous spirit 

 of the men of science who gave their services. 



Following up the work which resulted in the preparation of 

 the phosphoryl chlorobromides, JI. Besson (Cotiiptes rendiis, 

 May 11), by a similar method, has succeeded in preparing the 

 corresponding thiophosphoryl derivatives. A mixture of hydro- 

 bromic acid an<l thiophosphoryl chloride passed over pumice at 

 400°-50O° C. yields a liquid from which it is possible, by 

 fractional distillation under reduced pressure (60 mm.), to 

 .separate both the intermediate chlorobromides. These sub- 

 stances resemble in their general behaviour the corresponding 

 phosphoryl compounds. They undergo partial decomposition 

 when distilled under ordinary atmospheric pressure, and are 

 slowly acted upon by water. The chloromonobroinide, (PSCljBr), 

 has been previously obtained by Michaelis by the action of 

 bromine upon PSCl5(OCjH6), but his product seems to have 

 been impure. 



NO. 1386, VOL. 54] 



The additions to the Zoological Society's Gardens during the 

 past week include a Bonnet Monkey I^Macacus siniais, 9 ) from 

 India, presented by Mr. F. Greswolde-Williams ; a Red-fronted 

 Lemur {Lemur riififrons, i ) from Madagascar, presented by 

 Mr. E. A. Pardoe ; a Grison (Galictis vittata), a Black Tortoise 

 (Testiido carboimria), a Brazilian Tortoise (Testudo tahiilata), a 

 Rough Terrapin {Clemmys pitiicttilaria), two Scorpion Mud 

 Terrapins (Cinosternon scorpioides) from South America, pre- 

 sented by Mr. J. J. Quelch ; a Lesser Kestrel (Tiiiiumctdiis 

 ieinhris), captured off the coast of Sicily, presented by Mr. J. 

 L. SpauU ; a Natal Python {Python sebit, var. nataknsis), a 

 Ring-hals Snake {Sepedon hamachetes) from South Africa, pre- 

 sented by Mr. W. Champion ; a Common Viper ( Vipera beriis), 

 British, presented by Mr. H. L. C. Barret ; eight Esquimaux 

 Dogs {Caitis familiaris), Arctic Regions, deposited; a Pied 

 Crow Shrike {Strcpera graczilina) from Australia, two Whooper 

 Swans (Cypius musicus), European, purchased ; two Barbary 

 Wild Sheep (Ovis fragelaphus), born in the Gardens. 



Erratum. — In the letter entitled " Simple Huyghens' 

 Apparatus for the Optical Lantern," in the issue of Nature 

 for April 9, instead of "a thickness of li inches or more," read 

 " of 4 inch or more." 



OUR ASTRONOMICAL COLUMN. 



The System of Castor. — A very interesting discovery with 

 regard to this well-known binary star has been made by Dr. 

 Belopolsky (Bull. Jcad. Imp. Sci. St. Pcterslwiirg, vol. iv. 

 No. 3). In addition to the two luminous bodies, which perform 

 their revolution in a period of about 1000 years, Dr. Belopolsky's 

 observations indicate that the brighter star, a-^ Geminorum, 

 has a dark companion very similar to that of Algol, except 

 that it never produces eclipses. The existence of this dark body 

 was suspected in 1S94, and it was fully confirmed by photo- 

 graphs of the spectrum taken at Pulkowa early in the present 

 year, showing periodic changes in the velocity of the star along 

 the line of sight. Thirteen photographs were obtained, and 

 from these the velocities of a, Geminorum towards or away 

 from the sun were deduced. Although the available data are 

 insufficient for a complete determination of the orbit, it may be 

 taken to be circular as a first approximation, and a period of 

 revolution of 2 "98 days sufficiently accords with the spectroscopic 

 measurements. The proper motion of the system of a^ is I 'O 

 geographical mile { = 4'6 English miles) per second away from 

 the sun, while the relative orbital velocity is 4"$ geographical 

 miles (207 English miles) per .second. 



Dr. Belopolsky also tabulates the wave-lengths of some of the 

 principal lines in the spectrum of oj Geminorum, which some- 

 what resembles that of Sirius in having broad lines of hydrogen, 

 and many finer lines which are chiefly due to iron, a.^ Gemi- 

 norum gives a spectrum with less numerous lines. 



El-'FICIENCY OF PHOTOCRAPHIC TELESCOPES. — Dr. Isaac 

 Roberts has recently conducted an important series of experi- 

 ments with the view of ascertaining the relative efficiency of 

 a reflector and of portrait lenses for the delineation of celestial 

 objects {Monthly Notices, vol. Ivi. p. 372). It has often been 

 asserted that portrait lenses have, by reason of their short focal 

 lengths in relation to their apertures, greater photographic 

 power than instruments of other forms ; but this does not accord 

 with Dr. Roberts's experience. A portrait lens of Dallmeyer's 

 latest pattern, 3^ inches aperture and gh inches focus, and a 5-inch 

 Cooke patent triplet lens of 19 '2 inches focus, »-ere attached 

 with their cameras to the 20-inch reflector, and photographs of 

 the same regions were taken simultaneously with the three in- 

 struments. The 5-inch lens was stopped down to a ratio of i to 

 4'8, while the ratio of aperture to focus in the case of the re- 

 flector was I to 4 '9. In three exposures on the region of M. 33 

 Trianguli, the stars were 34 times more numerous on the re- 

 flector photograph than on the photograph taken with the 5-inch 

 lens in an equal angular area, and 7 '8 times more numerous 

 than in the case of the 34-inch lens. At the same time the re- 

 flector photograph showed the nebula more extensively, more 

 clearly depicted, at least two stellar m.ignitudes denser, and 

 with far more structural details than can be seen on the other 

 photographs. 



