374 



NA TURE 



S^Fcb. 1 8, 1886 



disappeared through association at the comparatively loiv 

 temperature of the stars. 



Fig. 27 gives us a representation of tire three chief 

 types of stellar spectra. 



It is thus manifest that in stars where the temperature 

 is very high and the dissociation very great we have 

 few-est lines, or at least fewest lines of that prominence 

 and thickness which entitle us to associate them with 

 substances existing below the surface of the stellar atmo 

 sphere. Here let us pause for a moment and reflect 

 what this implies. If each element were in reality a 

 simple body, and if the splitting up which occurs in the 

 spectrum of each were merely molecular and not atomic, 

 the result of a high tempei'ature in a mass of matter con- 

 taining presumably all the elements would certainly not 

 diminish the number of the spectral lines indefinitely. 

 For, even suppose that it split up all the molecular struc- 

 tures of each element into their simplest forms, yet on the 

 supposition that they are elements, the ultimate molecular 

 structure for one element would be different from that for 

 another, and there would thus be at least as many mole- 

 cular structures and spectral lines as there are elements. 

 On the other hand, if these substances are not elements, 

 we may imagine them to be split up into a comparatively 

 small number of ultimate structures, and we might eveii 

 imagine that at an enormously high temperature every- 

 thing might be reduced to a single structure. 



Thus the fact that in the hottest stars we have the 

 fewest atomic structures is in favour of the hypothesis 

 that the elements are not really simple bodies but com- 

 pounds, it may be, of some primordial atom. 



Let us now sum up the evidence derived from terrestrial 

 and celestial sources in favour of this hypothesis. 



First. There is experimental evidence of various kinds 

 tending to show that the so-called elements are not 

 essentially different from other bodies. 



Secondly. In the terrestrial spectrum of pure metals at 

 a high temperature certain lines are obtained for some 

 one element that are extremely near, if not coincident, in 

 spectral position with those obtained for some other 

 element or elements. These have been called "basic lines." 

 Thh-dly. We know that in the sun's atmosphere there 

 is a process at work tending to separate the various 

 molecular and atomic structures, and we find that the 

 greater number of the lines given out from the sun's 

 hotter regions are basic lines, such as we have above 

 defined. 



FourtJdy. In the very hottest stars, where the dissocia- 

 tion is greatest, we have only a few prominent lines given 

 out, these being lines belonging to hydrogen, calcium, 

 and magnesium. I think we must conclude that the 

 hypothesis that the elements are in reality compound 

 bodies offers, with our present knowledge, a very good 

 and simple explanation of the results of spectroscopic 

 analysis in the earth, the sun, and the stars. 



Now, bearinj in mind the extreme usefulness of some 

 such hypothesis to aid us in collecting facts, I do not 

 hesitate to say that this hypothesis can only be legiti- 

 mately overthrown in one of two ways. We may either, 

 in the first place, obtain some indisputable fact bearing 

 conclusively against the hypothesis that the elements are 

 compounds and in favour of their being essentially simple 

 bodies, and may thus overthrow the above hypothesis in 

 the same way that Fizeau, by his experiment, overthrew 

 the corpuscular theory of light, if, indeed, it had not 

 fallen to pieces before he made the experiment ; or, on 

 the other hand, the hypothesis that the elements are 

 essentially simple bodies may be applied by some skilled 

 advocate to our terrestrial and celestial spectroscopic 

 observations and a consistent explanation of these 

 afforded, simpler and better than that given by the above- 

 mentioned hypothesis. But until either of these two 

 things is done we are justified in using the compound 

 nature of the elements as a working hypothesis. 



It would, no doubt, be premature to bring it forward at 

 the present moment as an established theory, because an 

 established theory means a working hypothesis which, 

 having overcome the perils of infancy aiid youth, lives to 

 justify an honourable and useful existence on the principle 

 of the survival of the fittest. Balfour Stewart 



NOTES 

 The Paris Academy of .Sciences has suffeieil another loss in 

 the death of M. Jamin, Perpetual Secretary for the Sectioa of 

 Physical Science, and the immediate successor of M. Dumas. 

 M. Jamin can hardly be said to have filled his office, as he was 

 attacked by disease of the heart very soon after his nomination- 

 He was elected a member of the Academy in 1858 to fill the 

 place vacated by the death of Pouillet. He was a vsiry eloquent 

 teacher and debater, and a frequent contributor to the Kevi4e ties 

 deux Mondes. His " Cours de Physique a I'Ecole Poly- 

 technique," is a very extensive work. He also published many 

 papers in the Transactions of the Academy of Sciences, and 

 patented an electric light. He was born in 1813, and educated 

 at I'Ecole Normale. 



The death of Mr. Edward Thomas, one of the mast eminent 

 of English numismatists, took place on the loth in t. at 

 Kensington, in his seventy-third year. Afte.- a distinguished 

 career in the public service in India, he returned home and 

 devoted himself to the study of the antiquities and history 

 of India and Asia generally. He was a Corresponding 

 Member of the French Institute and of the St. Peters- 

 burg Academy, as well as a Fellow of the Royal Society. 

 His writings were very numerous, and many of them are still 

 only to be found scattered throughout the journals of different 

 learned Societies, to which he had contributed for upwards of 

 forty years. Amongst his most important works were liis edition 

 of Prinsep's "Antiquities," published in 1858; papers on 

 ancient Indian minerals in the yownal Asiatique ; on 

 early Sassanian inscriptions, seals, and coins ; his essay on 

 ancient Indian weights prefixed to the " Numisniata Orientalia" 

 is the standard work on the subject. Between 1848 and 1866 

 he contributed sixteen papers to the yournal of the Royal 

 Asiatic Society on Eastern coins. These were subsequently 

 republished under the title of " Tracts on Oriental Literature.' 



The death is announced of Dr. Heinrich Fischer, the mine- 

 ralogist and professor at the Freiburg University, well known 

 through his work on " Jadite and Nephrite." 



In a lively and interesting article in Tuesday's Times on the 

 work of tlie Smithsonian Institution in the field of ethnology it 

 is urged with some force that the British Government is bound 

 to render a similar service to science in the case of the numerous 

 races under our dominion, many of whom are dying out, or 

 changing their old habits and customs. " All the arguments 

 which could be urged for the maintenance of the Smithsonian 

 Bureau of Ethnology apply to the establishment of a similar 

 bureau for the British Empire. In British India the State from 

 time to time undertakes fragments of the task. Elsewhere it is 

 being effected occasionally and piecemeal. The want is of a 

 body which should carry on the enterprise as a whole, and in a 

 manner to borrow light from one quarter to elucidate the rest. 

 Types of tribal, social, and national existence are vanishing on 

 every side. They are changing, or giving place to new. Some 

 had always the germs of incurable decay in them. British 

 civilisation is treading out otaers. British dominion, whether 

 directly answerable or not for the mortality, is in the position of 

 administrator, and is bound to keep account of the estate of 

 ancient and curious memories. Being where and what it is, it 

 ought to be executing on a scale yet ampler the work the Smith- 

 sonian Institution is doing diligently from and at Washington. ' 



