September 5, 1912] 



NATURE 



iif its inventors, Mr. C. D. McCourt. The feature of 

 tile system is the combustion of the j^as and air mix- 

 ture as it is passing with tlie requisite velocity through 

 the interstices of a granular refractory material. .\ 

 steam boiler fired in this way evaporates i6 lbs. of 

 water per hour per square foot of heating surface. 

 The old student notes occupy fifteen pages. Referring 

 to work in the drawing office of a French engineering 

 firm, Mr. K. C. Barnaby writes : — " . . . there is 

 the delightful metric system. I cannot imagine any- 

 one who has worked and calculated in a Continental 

 office who would not wish our antiquated system of 

 weights and measures — well, where parallels meet." 



The fifty-seventh annual exhibition of the Royal 

 Photographic Society, which was opened last Monday, 

 will remain open until the 2ist inst. at the Gallery of 

 thi' Royal Society of British Artists, Suffolk Street, 

 Pall Mall. In the scientific and technical sections four 

 exhibits have been awarded medals. The first consists 

 of examples of a new photo-mechanical process by Mr. 

 .\. E. Bawtree, who has found a method of trans- 

 ferring the pigment of an impression from an engraved 

 plate, whether it is old or new, to a sheet of glass, so 

 producing a more perfect transparency than any 

 camera method can yield. He claims that not a grain 

 of the pigment is lost. From this transparency copies 

 of the original may be made by various photographic 

 or photo-mechanical methods as is well known. He 

 can then retransfer the pigment from the glass to 

 paper without the loss of even the finest detail. The 

 method of transfer is so easy that the author does 

 not yet describe it, because it enables facsimiles of 

 bank-notes and such documents to be prepared with 

 a very moderate outlay for apparatus. Dr. D. H. 

 Hutchinson's series of photomicrographs of the ova 

 of the ".lexican Axolotl show the development of the 

 embryo from the first day after the e^^ has been laid 

 up to the time of its escape from the egg. This, and 

 Mr. Farren's series of photographs of the little egret, 

 and .Mr. G. Busby's autochrome landscape, well 

 deserve tlie medals that have been aw-arded them. 

 .Among the numerous other exhibits we may perhaps 

 direct special attention to the radiographs of Dr. Hall- 

 Edwards, which show the effect of bismuth salts and 

 iodoform in indicating details with great clearness, 

 Dr. Thurstan Holland's "plastic" radiographs. Dr. 

 T. W. Butcher's high-power photomicrographs, and 

 Dr. Rodman's stereo-photomicrographs of the scales 

 on the wings of moths and butterflies and the hairs 

 on the leaves of plants, though it seems almost 

 invidious to do so where so much good work is shown 

 illustratfng many different branches of work. 



Parts ii. and iii. of the Subject List of Works on 

 Mineral Industries in the Library of the Patent Office 

 have just been published at the office, 25 Southampton 

 Buildings, Chancery Lane, W.C., price sixpence each. 

 Part ii. contains classified titles of works on iron 

 manufacture, alloys, and metallography, and part iii. 

 those relating to metallurgy (non-ferrous and general), 

 assaying, and fuel combustion. The lists, like others 

 in the same series, are most helpful guides to the 

 contents of a very valuable librarv. 

 NO. 2236, VOL. go] 



OUR ASTRONOMICAL COLUMN. 



The Spectrum of Brooks's Comet, igiic. — Some 

 excellent spectrograms of comet 1911c are reproduced 

 and their special features discussed by MM. de la 

 Baume Pluvinel and Baldet in the September number 

 of L'Astronomie. The spectrographs employed were 

 mounted at the Juvisy Observatory, and an examina- 

 tion of the complete series of plates shows very 

 markedly the spectral changes which took place as the 

 comet approached the sun ; between August and the 

 end of October a number of " unknown " radiations 

 between a. 4100 and a. 4000 suffered a considerable 

 diminution of intensity as compared with other radia- 

 tions. The wave-lengths of these lines, considered 

 precise to i A, are 4099, 4074, 4065, 4051, 4041, 4032, 

 and 4016. These radiations were peculiar to the 

 nucleus of the comet, being found neither in the coma 

 nor the tail, and as they became fainter the tail 

 radiations became strong ; it was also noted that in 

 the later spectra the tail radiations extended well to 

 the front of the comet's head, showing that in active 

 comets, such as this one and Morehouse's, the tail 

 matter is expelled in all directions. In Kiess's comet 

 it appeared to escape from one point only. Altogether 

 47 monochromatic images of the nucleus were counted 

 on the Juvisy plates, but the kathode spectrum of 

 nitrogen was not recognised among them. 



The Corona at the Total Solar Eclipse of .April 

 17. — .A drawing of the corona, made by Sefior J. Comas 

 Sola, at Barco de Valdeorras (Galicia), on April 17. 

 appears in No. 4597 of the Astroiiomischc Nachricliten. 

 .Although observers at other stations were uncertain 

 as to the definite apparition of the corona, Sefior 

 Comas SolA saw it well extended, and on his drawing 

 depicts it extending equatorially to about 2^ solar 

 diameters on either side of the sun. The drawing, 

 given principally to show the general form, repre- 

 sents a corona distinctly of the minimum type. The 

 same observer also describes his spectrum observa- 

 tions, while many others give the results of observa- 

 tions of the contacts, &c. 



The Di.«ieter of Neptune. — .An interesting paper 

 bv Dr. G. Abetti, discussing the various measures of 

 Neptune made since 1846, appears in No. 8, vol. i. 

 (second series), of the Mcinorie delta Societa degli 

 Spettroscopisti Italiani. He shows that the measured 

 diameter has, in general, tended to become less as 

 the aperture and magnification employed have in- 

 creased. Using only the results from apertures of 

 more than 40 cm. and magnifications greater' than 

 620, the mean values being 76 cm. and 794 respec- 

 tively, the diameter at unit distance comes out as 

 69'04" for the mean aperture, and 68' 98" for the mean 

 power ; other considerations show that the true value 

 differs but little from 69". Using this value, he then 

 calculates the true diameter as 5x10' km., the 

 density (earth=i) as 0*29 or (water=i) r6, and the 

 superficial gravity as I'I2, that at the earth's equator 

 being taken as I'o. As seen from the earth, the 

 apparent diameter ranges between 2-39" and 220". 



UNIVERSITY AND EDUCATIONAL 

 INTELLIGENCE. 

 BIR.^HN^■HAM. — The University has suffered a severe 

 loss by the death of the A'ice-Chancellor, Alderman 

 Charles Gabriel Beale, at the early age of 6g. Alder- 

 man B_eale, who was a graduate of Trinity College, 

 Cambridge, was one of the most prominent citizens of 

 Birmingham, having been elected to the mayoral chair 

 no fewer than four times. He was mainly instrumental 

 in carrving to a successful conclusion the great scheme 

 for supplving the cilv with water from the Welsh 



