February 6, 1902] 



NATURE 



325 



article on each canal and a digest of the report of the Canal 

 Commission ; it is illustrated by about forty views and diagrams. 

 In the ordinary number is a short summary of the matter to be 

 found in the supplement, and a full-page illustration showing 

 the two canals in plan. 



The National Geographic Magazint publishes, as a supple- 

 ment to its January number, the official map of the Philippines 

 prepared by the United States Signal Officer under the direction 

 of General Greely. The map is in two sheets, on a scale of 

 I : 900,000, and shows telegraph lines and cables, telephone 

 lines, open ports, lighthouse? and post offices. The spelling of 

 names is that adopted by the U.S. Board on Geographic Names. 

 A remarkable feature is the large amount of country, in the 

 island of Mindoro especially, which remains blank on the map, 

 awaiting exploration. 



Dr. Martin Knudse.v contributes a paper on the ocean- 

 ography of the straits connecting the Baltic and the North Sea 

 to the January number of La Geographie, in which he gives a 

 short account of the work of the Danish Commission during the 

 past ten years, and brings it into relation with the researches of 

 Pettersson and Ekman. The seasonal variations of the inflowing 

 and outflowing streams are fully described ; a section is devoted 

 to the discussion of the distribution of temperature in the 

 Kattegat and the western Baltic, and another to the relative 

 volumes of the Baltic current and the inflowing current of Salter 

 water, as deduced from the salinity observations. With regard 

 to the Baltic current, the remarkable result has been arrived at 

 that its volume is four to six limes greater than can be accounted 

 for by the supply of fresh water by rainfall in the Baltic basin 

 alone, and that this cause is largely assisted by the winds and 

 by the variations of atmospheric pressure on the surface of the 

 sea itself. 



A CATALOGUE of the types and figured fossils in the geological 

 department of the American Museum of Natural History, New 

 York, has been published as the eleventh volume of the Bulletin 

 of the Museum. It is needless to say that such catalogues are 

 of great service to palaeontologists. The Museum contains the 

 James Hall collection, which includes a large number of type 

 and figured Pala;ozoic fossils ; it also contains other interesting 

 and important collections from strata of various ages in North 

 America, including the fruits and seeds from the Eocene beds 

 of Brandon, Vermont, described by Lesquereux, Pliocene and 

 post-Pliocene fossils from South Carolina, &c. There are also 

 Cretaceous fossils from Syria, Jamaica, lVc. The term " type " 

 is employed to embrace not only the specimens actually used by 

 an author in the original description of a species, but those 

 specimens which have been used by the same author in the 

 further elucidation of the species in subsequent publications. 

 This valuable record, for which we are indebted to Mr. R. P. 

 Whitfield, the curator, and his associate, Mr. E. O. Hovey, 

 enumerates 8.^45 type and figured specimens, representing 

 2721 species and IQO varieties. 



Among the forthcoming publications of the Clarendon Press 

 is an authorised translation of Schimper's "Geography of 

 Plants," by Profs. Percy Groom and \V. R. Fisher. 



The third volume of Lord Rayleigh's collected papers, con- 

 taining papers published from 1887 to 1892, has been published 

 by the Cambridge University Press. The next volume will 

 bring the collection down to nearly the present time, and will, 

 it is hoped, be ready in about a year. The complete work will 

 then be reviewed in these columns. 



Messrs. F. Vie\veg and Son, Brunswick, announce that 

 the preparation of a biography of the late Prof. Helmholtz has 

 been undertaken by Prof. Leo Kunigsberger, and will be pub- 

 lished by them. The work will contain the letters which passed 

 NO. 1684, VOL. 65] 



between Helmholtz and his father, and correspondence with 

 personal and scientific friends. Many men of science will look 

 forward with pleasure to the publication of the biography of one 

 who contributed so much to the progress of natural knowledge. 



Mr. H. K. Lewis, of Gower Street, W.C, is extending his 

 circulating library of medical and scientific books. New books 

 and new editions are added to the library immediately on pub- 

 lication, so that it is possible for students with limited incomes 

 to keep themselves in close touch with all important additions to 

 scientific literature. The library provides a useful means for 

 obtaining standard works for study, or for examination with a 

 view to purchase. The lists of scientific books and periodicals 

 circulated by Mr. Lewis are worth attention. 



In the Siebenbiirgen salt district (Transylvania) are some 

 warm salt lakes which have recently been examined by A. V. 

 Kalecsinsky, chemist to the Hungarian Geological Survey. They 

 are remarkable for having a layer of warm or even hot salt water 

 between two colder bodies of water, the surface being fresh 

 water while the rest is highly saUne. In the Medoc See, for 

 example, when the surface was in summer at a temperature of 

 21' C, at a depth of i '3 metres the temperature was 56' C. and 

 the specific gravity I'l?, thence declining gradually to the 

 bottom to 19° C. with a specific gravity of fig, corresponding to 

 25 per cent, of salt in solution. The warm layer in summer 

 has been found to reach 70° to 71° C , but during winter 

 months it cools until the minimum in May is only 26° C. The 

 author concludes that the lakes are not fed by hot springs nor 

 warmed by chemical agency, but derive their heat from the sun. 

 As the specific heat of brine is below that of water, the saline 

 water is more readily warmed, and the fresh surface water pre- 

 vents any rapid loss of heat by radiation. Some future useful 

 application may, he thinks, be made of these natural heat- 

 accumulators. 



The additions to the Zoological Society's Gardens during the 

 past week include two Vulpine Phalangers (Trichosttrus vulpc- 

 ciila), two Laughing Kingfishers (Dacelo gigantea) from Aus- 

 tralia, a Weka Rail {Ocydromiis australis) from New Zealand, 

 presented by H.R. H. the Prince of Wales, K.G. ; a Malayan 

 Paradoxure (Paradoxurus hemaphroditus) from Burmah, pre- 

 sented by Capt. Burnett ; a Red-bellied Spider Monkey (Ateles 

 rnfiventris) from Colombia, a Long-haired Spider Monkey 

 (Ateles vetlerosus) from Central America, a Bungoma River 

 Turtle (Einyda granosa), seven Roofed Terrapins {Kachuga 

 tectum), five Hamilton's Terrapins (Damonia hamiltoni) from 

 India, two Bicheno's Finches (EstrelJa bichenovii) from Aus- 

 tralia, deposited ; a .Sykes's Monkey [Cercopithecus albigularis) 

 from East Africa, purchased ; three Red River Hogs (Potamo- 

 chaertts penicillatus) born in the Gardens. 



OUR ASTRONOMICAL COLUMN. 



Early Observations of Algol Stars. — In the Hai-vard 

 College Observatory Circular, No. 64, Prof. E. C. Pickering 

 furnishes particulars of additional observations of recently dis- 

 covered variables, which have been obtained from examination 

 of the photographs taken with the 8-inch Draper telescope. 



78 (1901) Cygni. — R.A. = 20h. 18m. 4S.-o; Decl. = -f 42° 

 46' -4(1855). 



This star was announced as variable by Mr. Williams. On 

 referring to the Harvard collection the star has been found on 

 177 plates, the first being on 1885 September 19 ten of the 

 photographs showing the star to be fainter than the normal 

 brightness. Determinations with the 12-inch meridian photo- 

 meter give the maximum magnitude as 1047, and taking this 

 value, a light curve has been determined from observations 

 with the 15-inch equatorial. The magnitude appears to de- 

 crease to about 1 3 '05 at minimum. With an adopted period 

 of 3d. loh. 49m. I2s. a table of residuals is formed from the 

 old and new measures, and more accurate results will probably 



