August 17, 1916] 



NATURE 



507 



OVR ASTRONOMICAL COLUMN. 



A Large Solar Prominence. — An eruptive promin- 

 ence of exceptional altitude was photographed by Mr. 

 Evershed at Srinagar, Kashmir, on May 26, 1916. 

 Photographs were obtained at intervals from near 

 the beginning of the outburst until the final fragments 

 had risen to a height of a little more than a semi- 

 diameter from the sun's limb. The velocity away 

 from the sun was. 190 km. per sec, and faint exten- 

 sions could be traced at 18' from the limb, representing 

 a height of close upon half a million miles. This 

 would appear to be the highest prominence which has 

 yet been recorded. {The Observatory, vol. xxxix., 

 P- 358.) 



The Spectroscopic Binary o- Aquil^^e. — ^The 

 variable radial velocity of this star, detected at 

 Mt. Wilson in 1912, has been further investigated by 

 Mr. F. C. Jordan (Pub. Allegheny Obs., vol. iii., 

 No. 22). The star is interesting as one in which both 

 components are readily obser\-ed separately. Both 

 spectra are of type B 8, and from their relative inten- 

 sities it is inferred that the components differ in 

 brightness by about half a magnitude. The period is 

 195022 days, with a probable error of about 8^ seconds. 

 The orbit is sensibly circular, and the velocities of 

 the components 163 and 199 km. per sec. respectively, 

 that of the primary being the highest so far known 

 with the exception of ^ Lyrae, V Puppis, and /i^ Scorpii. 

 The star is of further interest as an additional case 

 in which the K line of calcium indicates a velocity 

 differing from that given by other lines of the 

 spectrum. The mean velocity differs so little from 

 that of the system, -5 km., that it suggests an origin 

 of the line in the system itself. If the line were due 

 to absorption by a calcium cloud stationary with 

 respect to our stellar system, its velocity due to the 

 solar motion would be — 16 km. The individual plates 

 show considerable variations, but these are aoparently 

 unrelated to the oscillations of the component stars. 



j B.ANDED Spectra fro.m the Electric Furnace. — At 

 the Mount Wilson laboratory Dr. A. S. King has 

 investigated the conditions of occurrence in the elec- 

 tric furnace of the banded sp>ectra which have been 

 attributed to titanium oxide, magnesium hydride, aiid 

 calcium hydride {Astrophysical Journal, vol. xliii., 

 p. 341). .\11 the bands in question have been 

 identified In the spectra of sun-spots, and those of 

 titanium oxide are the most characteristic feature of 

 the spectra of Antarian, or third-type, stars. The 

 outcome of Dr. King's experiments on titanium is to 

 confirm the conclusion previously arrived at by Fowler, 

 that the bands attributed to the oxide of this element 

 are certainly dependent upon the presence of oxygen, 

 and to show that with a sufficient supply of oxygen 

 in the furnace the spectrum consists of the bands 

 alone. There was no evidence of a material change 

 in temperature caused by the introduction of 

 oxygen, and there would seem to be no reason for the 

 disappearance of the line spectrum unless an actual 

 compound were formed. In the case of magnesium 

 and calcium, the experiments similarly indicated a 

 clear dependence of the bands on the presence of 

 hydrogen, without any apparent change in the action 

 of the source. While the bands appeared through a 

 considerable range of furnace temperatures, the upper 

 limit for their greatest strength was about 2300° C. 

 There would accordingly seem to be ample justifica- 

 ition for regarding the presence of the three sets of 

 oands as evidence of a relatively low temf>erature in 

 sun-spots, and the occurrence of titanium-oxide bands 

 IS direct evidence of the presence of oxygen in the 

 i^tarian stars and in the sun. 



NO. 2442, VOL. 97] 



THE WORK OF THE NATIONAL PHYSICAL 

 LABORATORY DURING THE YEAR 1915-16. 



THE report of the National Physical Laboratory for 

 the year 1915-16 again presents a record of 

 useful national work. The importance of the labora- 

 tory has been rendered more prominent owing to the 

 war, not only because of the direct assistance it has 

 been called upon to giva to the Services, but also 

 through its co-operation in the solution of industrial 

 problems which our blindness and lack of national 

 prudence has been content to leave unattempted, an 

 open field wherein the scientific and technical organ- 

 isation of Giermany might find its reward. 



Two prominent members of the general board of 

 the laboratory, Sir Frederick Donaldson and Mr. 

 Leslie Robertson, lost their lives, in their country's 

 service, on the Hampshire. The board have put on 

 record in the report their appreciation of the services 

 rendered to the laboratory by these members of their 

 body. Sir Frederick Donaldson was an active mem- 

 ber also of the executive committee. Mr. Leslie 

 Robertson, from the nature of his duties as secretary 

 to the Engineering Standards Committee, had been 

 closely associated for many years with the work of 

 standardisation and maintenance of standards, which 

 constitutes one of the main functions of the labora- 

 tory. 



Last year the laboratory had also to mourn the 

 loss of two of its earliest and most active supporters. 

 Sir Andrew Noble and Sir Arthur Riicker, both mem- 

 bers of the Treasury- Committee, presided over by 

 Lord Rayleigh, which in 1897 reported in favour of 

 the establishment of the laboratory. 



One-quarter of the permanent staff of the laboratory 

 are at present on active service. Two who served in 

 France have lost their lives. One, taken prisoner at 

 Antwerp, succeeded about a year later in escaping 

 from Doberitz. During the past year the services of 

 all away have been much missed, and it has been 

 necessary to provide a constantly increasing tempor- 

 ary staff, including many women, of whom it is 

 recorded that their work has been very efficiently 

 done. 



Owing to the depletion of the staff and the large 

 demands made on the laboratory by the Admiralty, 

 the War Office, and the Ministry of Munitions for 

 the investigation of special questions, the research 

 work has necessarily suffered, and in many depart- 

 ments has' been altogether in abeyance. On the 

 formation of the Ministry of Munitions, Dr. Glaze- 

 brook, the director of the laboratory, was appointed 

 its scientific adviser on physical questions. The 

 laboratory undertook the testing of gauges required 

 in the manufacture of fuses and shells. The initial 

 difficulties were considerable : the degree of accuracy 

 needed in the gauges was scarcely realised at first 

 by many of the numerous manufacturers vho gave 

 their assistance to the Ministry in meeting the needs 

 of the Army, and the laboratory has earned their con- 

 fidence and appreciation by the valuable help it has 

 been able to give, both directly and indirectly, in the 

 improvement of the methods employed. 



The war has lent a great stimulus to the production 

 in this country of optical glass, an industry which had 

 previously tended more and more to become a Grerman 

 monopoly. The shortage in the early months of the 

 war must have been a source of most serious anxiety 

 to those responsible for the supply of optical muni- 

 tions, and it is a matter for congratulation that the 

 difficulty has been met so successfully. Research on 

 optical glass has now been undertaken by the labora- 

 tory, with the aid of a grant from the Privy Council 

 Committee for Scientific and Industrial Research. 

 This work is of the utmost national and scientific im- 



