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POPULAR SCIENCE MONTHLY. 



THE PROGRESS OF SCIENCE. 



It is frequently said that the days 

 of the discovery of general principles 

 and far-reaching laws are past, and that 

 students of science are now settling 

 down to minor questions and the elab- 

 oration of details. The amount of spe- 

 cialized work, unproductive of immedi- 

 ate result in general truths, is naturally 

 increasing, both because of the assiduity 

 of scientific workers and because each 

 general truth brings a number of minor 

 problems. But the acquisition of wide 

 theories is by no means at an end when 

 we are told, as we have been during the 

 last year, that the nebular hypothesis 

 of Laplace is at variance with the facts; 

 that the atoms are made up of smaller 

 bodies whose nature can be known; that 

 inertia and gravitation are not special 

 facts by themselves, but are the results 

 of the electrical charges of bodies. In 

 papers in the Journal of Geology and 

 the Astrophysical Journal, Prof. T. C. 

 Chamberlin and Dr. F. R. Moulton seek 

 to show that the nature of the earth's 

 atmosphere is not compatible with the 

 traditional idea of the formation of the 

 earth from a hot gaseous ring ; that the 

 force of gravity would not cause such 

 a ring to form a sphere; that the mat- 

 ter given off by a rotating spheroid of 

 gas would not go off in the form of 

 rings, and that the present mechanical 

 arrangement of the solar system could 

 not be derived from a spheroidal nebula 

 such as Laplace assumed. It is sug- 

 gested that the spiral nebulae may offer 

 conditions analogous to those of our 

 own solar system in its early stages. 

 The hypothesis receives confirmation 

 from the important paper published 

 just before his death by Keeler, and de- 

 scribed by Professor Campbell in the 

 obituary notice published above. Keel- 

 er's beautiful photographs with the 

 Crossley reflector, several of which are 



reproduced by Professor Newcomb in 

 the opening article of this issue of the 

 Monthly, indicate that most nebulae 

 are in fact spiral. 



Recent researches in molecular phys- 

 ics threaten to disqualify the time- 

 honored position of the atoms as the 

 smallest known particles of matter and 

 to push the analysis of material sub- 

 stances to a point where the dreams 

 of a primary order of sub-atoms or 

 corpuscles whose varying combinations 

 shall account for the so-called 'elements' 

 seems almost probable. The work of 

 Prof. J. J. Thomson and others on the 

 electrical condition of gases has resulted 

 in the hypothesis that the ions or bodies 

 carrying the electric charges are not 

 greater than one-thousandth the mass 

 of the hydrogen atom; further, that the 

 mass of each ion is the same in the 

 case of all the gases tried, regardless 

 of their atomic weights. The latter 

 statement indicates that atoms of 

 totally different constitution yet consist 

 of corpuscles that are alike at least in 

 mass. Although the experiments and 

 reasoning which have led to these con- 

 clusions are beyond the comprehension 

 of any but the specialist, and so cannot 

 be suitably given in this connection, it 

 should be remembered that the conclu- 

 sions are far from being mere specula- 

 tions. On the contrary, they are the re- 

 sult of the most careful experimental 

 work, accord well with a number of 

 facts and have already been tentatively 

 applied to the explanation of other 

 phenomena. Thus, Dr. Reginald A. 

 Fessenden has arrived at certain far- 

 reaching hypotheses concerning the pos- 

 sible explanation of inertia and gravita- 

 tion in terms of electric charges. In a 

 recent issue of Science he writes: "We 

 thus find that both inertia and gravita- 



