Mr. B. Stewart on the Solar Spectrum, 503 



We will here quote a remarkable fact bearing upon our theory, 

 which was lately communicated to us by Dr. Piccard. The 

 chamois-hunters of western Switzerland are accustomed, when 

 starting on long and fatiguing expeditions, to take with them as 

 provisions nothing but bacon-fat and sugar, because, as they 

 say, these substances are more nourishing than meat. What 

 they mean by this expression is, that they have learnt by ex- 

 perience that, in the form of fat and sugar, they can most con- 

 veniently carry with them a rich provision of force-producing 

 oxidizable matter. With regard to this point, we can assert, 

 from our own experience in the ascent of the Faulhorn, that in 

 spite of the amount of work and the abstinence for thirty-one 

 hours from albuminous food, we neither of us felt in the least 

 exhausted. This could hardly have been the case if our muscular 

 force had not been sustained by the non-nitrogenous food of 

 which we partook. 



LXXI. On Mr. Cooke's Observations of the Solar Spectrum, 

 By Balfour Stewart, M.A., F.R.S, 



To the Editors of the Philosophical Magazine and Journal, 

 Gentlemen, 



IN Silliman's Journal for March 1866, there appears a com- 

 munication from Mr. Josiah Cooke, Jun., Cambridge, U.S., 

 " On the Aqueous Lines of the Solar Spectrum," which commu- 

 nication has been republished in the Philosophical Magazine of 

 last month. 



The author, who has kindly forwarded me a copy of his paper, 

 alluded to his having visited Kew Observatory in the summer of 

 1864, when he was surprised to find my spectroscope less power- 

 ful than the one he was then using. He considers that " the facts 

 stated in his paper fully account for the discrepancies in the re- 

 presentations which different observers have given of the D lines/' 

 and that " the moist climate of England is the evident explana- 

 tion of the additional lines." 



Mr. Balfour Stewart, the Superintendent of Kew Observatory, 

 has forwarded me the following letter. You will observe that the 

 observations of Mr. Stewart and of the other Kew observers are 

 somewhat at variance with those of Mr. Cooke. 



Believe me, 



Yours truly, 



Clapham Common, May 8, 1866. J. P. Gassiot. 



Kew Observatory, May 7, 1866. 

 My dear Sir, — It has occurred to me that perhaps you might 

 like to know how far the observations made with your spectro- 

 scope at Kew corroborate the remarks of Mr. J. P. Cooke as to 



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