NA TURE 



[December 12, 1907 



Curtis increased Uie ventilation apertures about the mirror 

 so that about one-sixth of the area of the bacli of the 

 mirror was directly exposed. This, apparently, had little 

 effect, so a refrigerating machine was obtained and put 

 into operation. The machine is of the anhydrous ammonia 

 type, and is automatic in action. To coo! the mirror the 

 telescope is placed vertical, and a movable box brought 

 into position to enclose the cooling pipes and the mirror 

 end ; two electric fans circulate the cooled air freely 

 around the mirror. This operation is commenced about 

 three hours before sunset, and when the thermometer 

 shows a fall of 5° C. or 6° C. the case is removed, about 

 forty minutes before sunset. No moisture forms on the 

 silvered surface, which may be 3° C. or 4° C. below the 

 temperature of the surrounding atmosphere when observa- 

 tions commence. This method has proved very successful, 

 for focal changes are, as a rule, not noticeable, and 

 scarcely ever exceed five millimetres. Dr. Curtis's account 

 of his experiments also appears in the current number of 

 the Asfrophysical Journal, and is there illustrated by two 

 photographs, the one showing the telescope and spectro- 

 graph, the second showing the wooden cooling chamber in 

 position. 



Orbits of .Spectroscopic Binaries. — From plates taken 

 with the Mills reflector, the orbits of the spectroscopic 

 binaries a Carinae, a Pavonis, and k Velorum have been 

 determined by Dr. Curtis, and their elements are pub- 

 lished in No. 122 of the Lick Observatory Bulletins, 

 o Carina is a star of magnitude 3-5, and its spectral type 

 is given as B3A in the Harvard classification. According 

 to the elements now published, its period is 6-744 days, 

 the velocity of the system is +23-3 km., and the length 

 of the semi-major axis of the orbit is 1,960,000 km. For 

 a Pavonis (mag. 2-0) the period is 11-753 days, the velocity 

 of the system is 4-2-0 km., and the length of the semi- 

 major axis is 1,170,000 km. ; the orbit is nearly circular. 

 The period of if Velorum (mag. 2-6) is 116-65 days, the 

 velocity of the system =4-21.9 km., and the length of the 

 semi-major axis =73,200,000 km. All three stars are of 

 the same type of spectrum. 



Mellisii's Comet, 19071;. — A new set of elements and an 

 ephemeris extending to December 31-5 are given in Lick 

 Observatory Bulletin No. 124 for Mellish's comet. The 

 position for December 11-5 is a = oh. 12m., 8=4-27° 2', 

 about 1 3° south-east of a Andromeda?, and the brightness 

 is about one-third that at the time of discovery. 

 The following positions are taken from the ephemeris : — 

 December 23-5 (G.M.T.), a = 23h. 56m., 8=4-26° 30'; 

 December 31-5, a = 23h. 52m., 8=4-26° 30' (brightness 

 = 0-09). 



Solar Prominences in 1906. — Prof. Ricco's annual 

 summary (1906) of the prominence observations made at 

 Catania appears as an abstract from vol. xxxvi. (1907) of 

 the Memorie della Societa degli Spettroscopisti Italiani. 

 The following are the mean values for the year : — daily 

 frequency = 2-7, complete extension .along the limb = 7°-s, 

 height of prominences = 44".2. As one would expect near 

 the epoch of maximum, these values are nearly equal to 

 those obtained in 1905. It is interesting to note that 

 whereas the sun-spot frequency curve showed maxima in 

 February and November, 1905, the prominence maximum 

 appears to have been relatively retarded, the second 

 greatest maximum recorded at Catania having occurred in 

 March, 1906. Considering the heliographic latitude of the 

 prominences in 10° zones, the principal maximum took 

 place in +20° to +30°, as in 1905, but the secondary 

 maximum was elevated ten degrees from +60° to +70° 

 to +70° to +80°; this is another characteristic of the 

 maximum epoch. Excepting the fourth trimestre, the 

 number of prominences observed in the northern hemi- 

 sphere of the sun was greater than that observed in the 

 southern hemisphere, the numbers for the year being 284 

 and 185 respectively. 



Search Ephemeris for Comet 1907a (Giacoeini). — 

 Believing that comet 1907a might still be observed in 

 large instruments or found on long-exposure photographs. 

 Prof. Weiss publishes a search-ephemeris for this object in 

 No. 4218 of the Astronomische Nachrichieii (p. 300, 

 December 2). The comet is now some 10 111. west of 

 a Persei, and its estimated magnitude is 13-S. 



PRIZES AWARDED BY THE PARIS 

 ACADEMY OF SCIENCES. 



Geometry. — The Francoeur prize is awarded to Emile 

 Lemoine, for the whole of his work in mathematics ; the 

 Bordin prize to F. Enriques and F. Severi jointly, the 

 Vaillant prize being divided between J. Hadamard, Arthur 

 Korn, Giuseppe Lauricella, and Tommaso Boggio. 



Mechanics. — .\ Montyon prize is awarded to M. Cuenot, 

 for his e.xpcrimental studies on the fle.xure of rails ; an 

 exceptionally honourable mention to M. Petot, for his 

 work on the theory of automobiles ; the Poncelet prize to 

 Colonel Renard, tor his mathematical and experimental 

 researches in mechanics, and for his contributions to 

 aeronautics. 



Navigation. — The extraordinary prize of six thousand 

 francs is divided between M. Gayde (two-thirds) and 

 J. Est^ve (one-third), the Plumey prize not being awarded. 



Astronomy. — The Pierre Guzman prize is not awarded. 

 T. Lewis receives the Lalande prize, M. Giacobini the 

 Valz prize, and M. Gaillot the G. de Ponticoulant prize. 



Geography. — The Gay prize is awarded to Jean Charcot, 

 for his Antarctic explorations, the Tchihatchef prize being 

 divided between Jacques de Morgan and Paul Cr^pin 

 Bourdier de Beauregard. 



Physics. — Lucien Poincar^ receives the Hubert prize, for 

 his book on modern physics ; P. Langevin the Hugues 

 prize, for his work on the mobility of gaseous ions and 

 the properties of electrons ; M. Mathias the Gaston Plants 

 prize, for his work on terrestrial magnetism ; Paul Villard 

 the La Caze prize, for the whole of his researches in 

 physics ; and Pierre Weiss the Kastner-Boursault prize, for 

 his experimental and theoretical work in magnetism. 



Chemistry. — The Jecker prize is divided between MM. 

 Blaise, Marcel Del^pine, and Hamonet, and the Cahours 

 prize between M.M. Gain, Mailhe, and GuiUemard. A 

 Montyon prize (unhealthy trades) is awarded to AL Bonne- 

 ville, for his discovery and manufacture of a cement in 

 which metallic zinc replaces the red lead commonly used. 



Mineralogy and Geology. — M. Martel is awarded the 

 grand prize of the physical sciences, for his studies on 

 underground waters, and J. J. H. Teall the Delesse prize, 

 for his researches in petrography. 



Botany. — ^The Desmaziferes prize is awarded to General 

 E. G. Paris, for his " Index Bryologicus " ; the Montagne 

 prize to F. Gueguen, for his work on the lower fungi ; 

 the De Coincy prize to F. Gagnepain, for his work on the 

 classification of the Zingibcraceae ; the Thore prize to M. 

 Bainicr, for his work on the lower fungi ; and the de la 

 Fons-M^licocq prize to C, Houard, for his memoir on the 

 parasitic deformations of plants in northern France. 



Anatomy and Zoology. — Charles AUuaud receives the 

 .Savigny prize, for his work on the invertebrates of Upper 

 Egypt and the adjacent portions of Africa. 



Medicine and Surgery. — Montyon prizes are awarded to 

 J. Henniquin, for his work on the treatment of fractures; 

 C. Levaditi, for his researches on Treponema pallidum ; 

 and Maurice ViUaret, for his researches in connection with 

 urinary secretion. Mentions are accorded to A. Thiroux 

 and M. d'Anfreville, for their memoir on malaria in 

 Senegal ; MM. Nicolle and Mesnil, for their memoir on the 

 treatment of trypanosomiasis by the benzidine colours ; and 

 Ren^ Gaultier, for his memoir on the functional explora- 

 tion of the intestine by analyses of the faeces. Gustave 

 Martin, Georges P^caud, Pierre Breteau and Paul Woog, 

 .\. Desmoulifere, and M. Guisez receive citations in connec- 

 tion with this prize. J. Guiart and L. Grimbert receive the 

 Barbier prize for their book on chemical, microscopical, 

 and pathological diagnosis. The Bryant prize (interest 

 only) is divided between MM. Vaillard and Dopter, for 

 their researches on bacillary dysentery, and J. Ferran, for 

 his work on the cholera bacillus. The Godard prize is 

 given to Victor Nicaise, for his memoir on the indications 

 and therapeutic value of total or partial nephrectomy in 

 the treatment of hydatoid cyst of the kidney ; the Baron 

 Larrey prize to G. H. Lemoine, for his work on military 

 hygiene ; the Bellion prize to .'\. Chantemesse and F. Borel, 

 for their memoir on the protection of the country from 

 diseases introduced from abroad; the Mfegc prize to J. 

 Castaigne and F. Rathery, for their work on the lesions 

 of the convoluted tube of the kidney ; and the Chaussier 

 prize to A. Lacassagne, for his work on forensic medicine. 



NO. 1989, VOL 77] 



