SCIENCE 



AN ILLUSTRATED JOURNAL PyBLISHED WEEKLY. 



Verite sans peur. 



NEW YORK: THE SCIENCE COMPANY. 



FRIDAY, JULY 6, 1888. 



not necessarily vary directly with the temperature, and that it is 

 very doubtful whether we may apply to the material of the sun the 

 observations on radiation which we have obtained in the laboratory. 



In the different theories which have been suggested to 

 explain the constancy in the radiation from the sun, at least during 

 considerable time-intervals, it has been generally supposed that the 

 temperature of the sun has not varied essentially, and in order to 

 explain this constant temperature it has been necessary to find 

 some source for an accession to the sun's heat. For this purpose 

 we have the chemical theory of burning, the meteorite theory of 

 heat being produced by the falling into the sun of vast masses of 

 meteors, and the theory of contraction. In all these theories it 

 is assumed that the temperature of the sun must remain constant 

 if the amount of warmth radiated from it is to remain the same, 

 and that, if the temperature of the sun were to sink, the amount of 

 energy radiated must decrease. Mr. John Aitken, in a recent num- 

 ber of the Proceedings of the Royal Society of Edinburgh, calls 

 attention to the fact that these premises are not absolutely neces- 

 sary', since the amount of radiated energy may increase even when 

 the temperature decreases. The facts upon which he bases this 

 possibility are the following : i. It is known that the power of ra- 

 diation varies with the form of the material, for instance, the flame 

 of the Bunsen burner, although of a higher temperature, radiates 

 less warmth than that of the ordinary gas-flame ; 2. As a rule, the 

 elements radiate less warmth than compounds, and observation has 

 established that the amount of radiation increases with the com- 

 plexity of the molecular structure ; 3. It is well established that at 

 high temperatures dissociation takes place, and compounds be- 

 come less complex. We see, therefore, that in the sun, on account 

 of its high temperature, substances must exist in less complex 

 form than on the earth, to which conclusion many of the recent de- 

 ductions of Lockyer specially point. It is therefore probable that 

 the radiating power of the material of the sun is far less than that 

 of the earth ; also that the hotter the sun, the simpler its constitution, 

 and just so much smaller its radiating power. It is, then, no longer 

 necessary to assume that the temperature and the amount of 

 radiated warmth from the sun are proportional. The temperature 

 can decrease, and at the same time, on account of the change in the 

 chemical constitution of the sun, the amount of radiation may in- 

 crease. Sir William Thomson has recently calculated the numeri- 

 cal data, according to the Helmholtz theor)' of the sun's warmth, 

 and has found that the sun would have to contract thirty-five 

 metres yearly in order to produce the energy which it radiates ac- 

 cording to Pouillet's measurements. In this connection it should 

 be said that Langley's measurements give a far larger warmth- 

 radiation from the sun, and that they are probably too small ; so 

 that the sun would have to contract much more than thirty-five 

 metres a year in order to produce its radiating energy through the 

 force of gravity. But evidently energy would be produced in the 

 sun in other ways during the cooling-off. The falling temperature, 

 for instance, would allow of compounds being produced, which act 

 of burning, as it were, would add to the temperature. Mr. Aitken 

 acknowledges that his suggestions are of the nature of speculations, 

 but he has published them in order to bring out the possibilities 

 that the radiating power of the sun may have changed, qualita- 

 tively and quantitatively, from time to time, that its amount does 



Among the ■ movements ' agitating the country is one known 

 as the 'Old South Work.' This is not, as might be supposed, 

 a move to stop the growth of the ' New South,' of which we hear 

 so much, but an attempt, and a vigorous one, which started with 

 some public-spirited ladies of Boston, with Mrs. Mary Hemenway 

 at the head, to interest and instruct the population now living with- 

 in the borders of the United States in the history of the country, 

 especially in so far as it has an influence on present conditions. 

 Too much time has been spent in the schools in laying before the 

 pupils the, at this epoch, unimportant details of the early Indian 

 wars, with the result of leaving them uninformed of later events, 

 the effects of which have a much more immediate influence on their 

 lives. Many believe that the American mind is empty of American 

 history, and fear that this may lead to ignorance of those principles 

 which have given us the success which is now our portion. But 

 why call this movement to educate Americans in what their fathers 

 and their grandfathers did the ' Old South Work ' .' It is simply 

 that because of this ignorance, which bred indifference, the people 

 of Boston were willing a few years ago that the Old South Church, 

 one of the theatres for some of the most stirring acts of the Revo- 

 lution, should be wiped from the face of the earth. To save the 

 building as a reminder of the revolutionary deeds of Boston, Mrs. 

 Hemenway gave liberally of her time and money. This was one 

 act in striving to interest Americans in America and her history ; 

 and for some years Mrs. Hemenway was nearly alone in sustaining 

 the ■ Old South Work.' Now we are glad to chronicle that the 

 movement has grown, and has gone West. At Chicago Mr. Edwin 

 D. iVIead has instituted a series of lectures. In Madison, Wis., a 

 similar course has proved so popular that hundreds have been 

 turned away each evening for lack of room. Again, in Indianapo- 

 lis this instruction of Americans in what Americans have done has 

 been found to meet such approval as to lead to similar courses in 

 the larger towns of Indiana. We hope, that, like most ' move- 

 ments ' which go from the East to the West, this may prove to 

 have the necessary staying qualities, and that the rising generation 

 may know how the political problems they have to solve have 

 grown from what went before. 



THE GOVERNMENT E.XHIBIT AT CINCINNATI. 



The National Museum, the Smithsonian Institution, the United 

 States Geological Survey, and the Bureau of Ethnolog)' will make 

 a joint exhibition at the Cincinnati Centennial. Although the time 

 for preparation has been verj' short, the law making the necessary 

 appropriation not having been approved until May 2S, the govern- 

 ment scientific exhibits will be in Cincinnati in good season, and 

 will constitute one of the most interesting features of the exposi- 

 tion. 



In determining what to show, those in charge have been greatly 

 embarrassed by the abundance of material from which to choose. 

 Cases of selected objects will be taken from several departments 

 of the National Museum, but mainly from the departments of an- 

 thropolog)', zoology, and of arts and industries. Those selected 

 from the department of anthropology will illustrate the plan upon 



