428 



NATURE 



[July 20, 19 16 



OVR ASTRONOMICAL COLUMN. 



Origin of Group G of the Solar Spectrum. — In 

 a preliminary note presented at the June meeting of 

 the Royal Astronomical Society, it was announced by 

 Messrs. Newall, Baxandall, and Butler that the group 

 of lines in the solar spectrum marked G by Fraun- 

 hofer had been proved by them to be mainly due to 

 absorption corresponding with the hydrocarbon band 

 about wave-length 4314. The band in question is 

 well-known from its occurrence in the "candle-flame" 

 spectrum, where it appears in association with the 

 " Swan " bands, and Lockyer's work has shown that 

 it is the characteristic band of the spectra of undis- 

 sociated hydrocarbons. The conspicuous presence of 

 the band in the Fraunhofer spectrum is in striking 

 contrast with its absence from the spectrum of the 

 chromosphere as photographed during total eclipses, 

 and further investigation of the details, which is in 

 progress at the Solar Physics Observatory, will prob- 

 ably throw light on this important difference. The 

 discovery of the origin of the G group will doubtless 

 also be of considerable importance in connection with 

 the interpretation of stellar spectra, as a gradual re- 

 duction in the intensity of the group on passing to 

 stars hotter than the sun is a well-marked feature of 

 the stellar sequence. 



Variable Stellar Spectra. — In continuation of pre- 

 vious work on the spectra of Cepheid variable stars 

 Mr. Harlow Shapley has recently obtained 150 spectro- 

 grams of representative stars of this class, using the 

 lo-in. portrait lens and objective prism of the Mount 

 Wilson Observatory (Proc. Nat. Acad. Sci., vol. ii., 

 p. 208). The eleven stars investigated have periods 

 ranging from nine hours to twenty-seven days, and 

 include some well-known naked-eye variables, and 

 some for which orbits have been computed from 

 spectroscopic data. For some of the stars the place 

 of greatest intensity of the general spectrum had 

 already been observed to shift towards the blue on the 

 approach of maximum luminosity, and it has now 

 been proved in addition that the details of the spectra 

 change with the phase of the variable, in accordance 

 with the normal stellar sequence — that is, when the 

 star is at maximum brightness, its spectrum corre- 

 sponds to a higher stage of the spectral series than 

 when at minimum. The change of spectrum was 

 particularly easy of observation in the case of small 

 dispersion spectra of the F type, where the variations 

 in the relative intensities of Hy and the G group were 

 very marked ; this is especially interesting in connec- 

 tion with the recent discovery that the G band is of 

 hydrocarbon origin (see preceding note). As examples 

 of the range of spectral variation the following may 

 be noted : — 8 Cephei, F2 to G3 ; RR Lyrae, B9 to F2 ; 

 RT Aurigae, A8 to Go. It is inferred that all 

 Cepheids, including those of the cluster type, vary 

 periodically in spectral class, as well as in magnitude 

 and radial velocity. 



A Large Meteor.— On July 8, at 11.59 p.m. G.M.T., 

 a large meteor equal to Venus was seen at Bristol by 

 Mr. Denning, and at Totteridge by Mrs. Wilson. The 

 radiant point was at 22° + 24°, and the height of the 

 object was from 77 to 51 miles. Its luminous course 

 was 120 miles long, and observed velocity 32 miles 

 per second. 



The Extraordinary Meteoric Shower of June 28. 

 — Mr. Denning has been endeavouring to collect ob- 

 servations of this event, but it seems to have been 

 witnessed by very few persons. The sky was cloudy 

 in the eastern counties of England, but all over the 

 west, from Bournemouth to Fleetwood, the weather 

 seems to have been favourable. 



NO. 2438, VOL. 97] 



An observer living at Birmingham states that be- 

 tween II and 12 p.m. G.M.T. he saw nearly one 

 hundred meteors, and that the radiant point was 

 between the stars Eta and Zeta Ursae Majoris, He 

 describes the meteors as often dropping over the S.E. 

 and E. horizon. They were frequently of a golden 

 hue, with very short paths and moderately slow in 

 their flight. Several of the larger meteors were 

 bluish-white, and flashed out with startling sudden- 

 ness and brilliancy, sufficient to render them visible 

 through the cloud stratum w^hich gathered in various 

 parts of the sky. 



Another observer at Bournemouth says that at 

 II p.m. G.M.T. he noticed three bright meteors in 

 about as many minutes, and that this rate of appari- 

 tion appeared to be maintained until the early dawn. 



This shower is certainly the richest which has been 

 observed since the Leonid display of November, 1903, 

 and being altogether unexpected and unknown in- 

 creases its importance and makes it very desirable 

 that it should be fully investigated. Possibly the 

 orbit of some recent comet may be found to coincide 

 with it. It is certainly curious that definite showers 

 proceed from the same apparent radiant point in 

 Quadrans on about January 2-3, March 27-30, June 

 28, and October 2, the intervals approximating three 

 months. 



NATIONAL INTEREST IN MINERAL 

 RESOURCES. 

 "r HE United States Geological Survey has issued 

 A its usual series of bulletins dealing with the 

 mineral production of America in the year 19 14. As 

 pointed out in the introductory section, this com- 

 pilation is the thirty-third of the published reports of 

 the Mineral Resources Division of the Geological 

 Survey, and thus enables comparisons to be instituted 

 extending over a third of a century. The series is, 

 however, rendered of still greater interest owing to 

 the inclusion in it of an article by G. O. Smith, 

 director of the Survey, on "The Public Interest 

 in Mineral Resources." It need scarcely be said 

 that this is written entirely from the American 

 point of view; at the same time, it is very largely 

 applicable to conditions in this country, because, as 

 is well known, America and Great Britain stand 

 practically alone amongst the world's great mineral 

 producers in their system of mineral ownership. 

 Everywhere the mineral resources of a country have 

 been recognised since Roman times as originally the 

 property of the State, to be administered for the 

 benefit of the nation at large. The fact that the actual 

 exploitation of its mineral deposits by the State is 

 an unsatisfactory arrangement has been pretty uni- 

 versally recognised ; there are a few isolated examples 

 of such exploitation, which may succeed here and 

 there under abnormal conditions, and the German 

 Empire has carried this method further than any 

 other State, but even in that autocratically governed 

 country, where the working community is treated! 

 as a well-drilled machine subservient absolutely to 

 the will of the ruling classes. State-worked mines 

 cannot be described as successful. Apart from this 

 ineffective method of dealing with their mineral 

 wealth. States can choose between two very different,— 

 but both highly efficient, principles. Most of the great* 

 Continental States adopt the mining concession prin-li 

 ciple ; under this the State retains for all time its ' 

 absolute ownership of the minerals, but grants con- 

 cessions to individuals or corporations under which 

 these are allowed to exploit the mineral deposits upon 

 payment to the State of a definite proportion of the 



I 



