May 26, 1 910] 



■overcome the difficulty experienced by lecturers in causing 

 ■water to freeze by its own evaporation. A glass tube 

 50 cm. long and 5 cm. diameter is closed at both ends 

 and filled with coarse glass wool to give more surface. A 

 lateral tube near one end connects with a round-bottomed 

 flask (or, better still, with a Dcwar flask) ; another lateral 

 tube near the other end connects with an exhaust pump. 

 The flask is first half-filled with water, and the glass wool 

 is saturated with fresh strong sulphuric acid. The forma- 

 tion of ice is very rapid. Grace's apparatus for determin- 

 mj; the mechanical equivalent of heat also deserves men- 

 tion as being a cheap pattern of the modern rotating 

 cylinder form of apparatus for this purpose. 



The May number of Knowledge appears under new 

 auspices. The editors are now Mr. Wilfred Mark Webb 

 and Mr. E. S. Grew ; and Hardwicke's Science Gossip 

 is incorporated with the journal, as well as Illustrated 

 Scientific News. In an introductory note Principal Miers 

 gives encouragement to scientific amateurs to pursue their 

 observational work in spite of the gulf that may exist 

 between them and the trained specialist. In astronomy 

 and natural history particularly, the work of amateurs is 

 often of great value to science, and any efforts made to 

 stimulate it must be appreciated by professional men of 

 science. The new number of our contemporary should be 

 of assistance in this direction. There are several fine 

 illustrations in the form of plates and other figures, and 

 the articles are by contributors who write with authority 

 and not as the scribes. .Among the astronomical articles 

 we notice one on Halley by Mr. T. A. Bellamy, a 

 characteristic contribution by Mr. J. E. Gore on counting 

 the stars, and a description of Prof. Lowell's observations 

 of Martian canals. Dr. D. H. Scott, F.R.S., writes upon 

 the earliest flowering plants — a subject which he has made 

 f^is own — Prof. F. Cavers upon liverwort^r and Prof. 

 A. W. Porter upon electromagnetic mass. There are ako 

 the usual notes upon recent advances in the various depart- 

 ments of science, and reviews of books. We offer our 

 congratulations to the editors upon the attractive character 

 of their first number, and trust that their efforts to pro- 

 mote and extend intelligent interest in science will meet 

 with success. 



Botanists alone, so far as we are aware, have a journal 

 dealing purely with the jests and humours of their subject. 

 The first number of the Sportophyte, edited by Dr. Marie 

 Stopes, emanates from Manchester University, and is to 

 appear yearly. It contains anecdotes, verse, and articles 

 parodying serious journals, of which the highly technical 

 and friendly humour will appeal to professional botanists. 



The first part of a catalogue of books on natural history, 

 to be obtained from Mr. Francis Edwards, 75 High Street, 

 Marylebone, W., has been received. It is concerned with 

 miscellaneous and general books and those dealing with 

 ornithology and oology. The second part of the catalogue 

 will deal with works on botany, gardening, ichthyology, 

 and other subjects. 



OUR ASTRONOMICAL COLUMN. 



Total Solar Eclipse of May 9. — .According to the Daily 

 Mail of May 19, Mr. Driffield, a sur^^eyor, reported to 

 Mr. Baracchi, director of the Melbourne Observatory, that 

 he observed the solar eclipse of May q at Queenstown, 

 Tasmania, in clear weather. .According to him, the 

 corona appeared regular jn form, concentric with and 

 evenly distributed around the moon's disc, except in the 



NO. 21 17, VOL. St,'] 



NATURE 



38. 



south-eastern quadrant, where two streamers were seen 

 running straight for some distance, and then curving 

 downward like a plume. The e.xtent of the corona was 

 more than half a degree from the limb. Its structure was 

 striated, the colours merging gradually from deep orange 

 to pale green. The streamers were two moon's diameters 

 in length. Mr. Baracchi is recorded to have said that this 

 is the best observation which was obtained. 



Solar Activity. — .After a period of quiescence the sun 

 has, during the past week, exhibited a recrudescence of 

 spot activity. Several moderately sized groups have been 

 observed containing well-defined extensive umbrae. 



C0.MET 1910a. — .According to an ephemeris published by 

 Prof. Kobold in No. 4410 of the Astronomische Nach- 

 richten, comet 1910a is still almost stationary to the west 

 of the Great Square, and its estimated magnitude is about 

 120. For May 27 its position is given as 



o (i9ioo)=:22h. 3i-5m., 5=-f-29° 298'. 



The Problem of the Resisting Mediu.m. — In No. 4408 

 of the Astronomische Sachrichten Mr. Selig Brddetsky, 

 of Cambridge Lniversity, discusses Prof. See's assump- 

 tions concerning the possible part played by a resisting 

 medium in the capture of satellites. In conclusion, he 

 shows that the arguments employed by Prof. See will not 

 stand close analysis, and are such as to render the possi- 

 bility of capture, with an assumed resisting medium, very 

 uncertain. That such a satellite as the moon was cap- 

 tured in the manner suggested appears to be extremely 

 improbable ; while some of the larger planets have appar- 

 ently been able to capture a number of comets, rendering 

 them periodic, there is no known case in which the earth 

 has been able to perform a similar operation. 



The Calcium Bands at \ 6382 and A. 6389. — In the 

 spectra of sun-spots the calcium bands with heads at 

 \\ 6382 and 6389 are an important feature, to which 

 attention was directed by Prof. Fowler, but their precise 

 origin is not quite settled. Investigations on this point 

 have been carried out by Prof. Barnes at Bryn Mawr 

 College, who describes his latest results in No. 2, vol. 

 xxxi., of the Astrophysical Journal. 



In dry air at atmospheric pressure, and with pure 

 metallic poles, these bands do not appear in the arc spec- 

 trum, but with the pressure reduced to 3 cm. of mercury, 

 or less, they come out strongly. In atmospheres of dry 

 hydrogen and pure dry nitrogen the bands do appear, but 

 not so strongly as when the arc is run in vacuo ; with 

 the arc burning in SO, they do not appear. 



It has been suggested that these bands are due to a 

 compound of calcium and hydrogen, but, from his experi- 

 ments. Prof. Barnes concludes that they may be considered 

 as true metallic radiations, a conclusion which is important 

 in discussing the probable origin of the sun-spot spectrum. 



Stars with Variable Radial A'elocities. — In No. 2, 

 vol. xxxi., of the Astrophysical Journal, Mr. O. J. Lee 

 publishes the results of recent observations of radial 

 velocities with the Bruce spectrograph at the Lick 

 Observatory. For o Cygni a range of 9 km., from —9-0 

 to — o-i km., was found, but the observations do not 

 suggest a period. Two members of the Taurus stream of 

 stars discovered by Prof. Boss, Nos. 1007 and 1092 in his 

 catalogue, have also been shown to vary their radial 

 velocities. The first is 58 Tauri, the range of its velocity 

 being from +41 to +i-i km., and the second is 

 B.D. 7° 681 Tauri, which exhibits a range of from 

 -(-34 km. to -I- 17 km. Pegasi is also shown to be a 

 spectroscopic binary with a range of from —32 to 

 + 19 km., and on one plate shows a very faint component 

 at 4-62 km. 



OCCLLTATION OF MaRS BY THE MoON ON .ApRIL I3. 



Through a break in the clouds Dr. W. Krebs was able 

 to observe the last contact during the occultation of Mars 

 by the moon on .April 13, and, in No. 4407 of the Astro- 

 nomische Xachrichten, he gives the time as loh. 49m. 30s. + 

 15s. (G.M.T.). 



