408 SCIENTIFIC RECORD FOR 188'i. 



tallied, enforcing the diatbeimancy of gases and the opaqueness of 

 vapors. He also further claims that his views are independently con- 

 firmed by observations of Professor Langley on Mount Whitney. Tyn- 

 dall states that in November, 1880, he resumed Investigations in ref- 

 erence to radiant heat, and it is to be hoped that his recent work will 

 ere long be published in full. [Nature, xxv, p. 233.) 



Captain Abney in a lecture on solar physics has given a general view 

 of the theory in practice of the photography of the ultra-violet and 

 especially the ultra-red portion of the spectrum. It is to be hoped 

 that the study of this subject and the application of Eowland's perfect 

 cylindrical gratings will enable us to fix for future study those bands 

 due to the absorption of solar radiation by our atmosphere that have 

 been so laboriously studied by Langley with the help of his bolometer. 

 (Nature, xxv, p. 16L*.) 



In Nature, xxvii, p. 15, will be found all necessary details as to his 

 method of photographing the infra-red portion of the spectrum. He 

 states that in i)hotographs taken at an elevation of 1,000 feet the general 

 absorption due to water almost vanishes, but the presence of other ab- 

 sorbents, especially alcohol vapor, still higher up, becomes demonstrable. 

 Fuller details of Professor Langley's results were communicated by 

 him in immediate connection with the address of Captain Abney to the 

 British Association at Southampton, and are published in Nature, 

 XXVI, p. 526. 



Langley also communicated his results to the Paris Academy of Sci- 

 ences, and he estimates that the solar heat on a square centimeter at the 

 outer surface of the atmosphete would raise one gram of water in one 

 minute about 3^ C. Of all this solar energy one-fourth is to be found 

 in the visible spectrum and ultra- violet portion; the other three-quar- 

 ters exist in the infra-red. In general, absorption increases as the wave 

 length diminishes. {Nature, xxvi, p. 520.) 



Professor Langley communicates to Nature, and also to the Paris 

 Academy, a short account of some results derived from the spectro- 

 scopic and bolometric observations on Mount Whitney, in Southern 

 California, at elevations from 4,000 to 15,000 feet. The expedition was 

 largely at the expense of the Signal Service and a private citizen of 

 Pittsburgh. His observations were directed first to the amount of heat 

 that the sun sends to the earth, and he concludes that the true solar 

 constant is at least one-half greater than that given by Pouillet, and 

 again that the so-called temperature of space must be lower than that 

 assigned by Pouillet, and finally the bolometer observations show a dif- 

 ferent distribution of solar energy at the upper station from that of the 

 lower, so that without our atmosphere the sun will appear with a strong 

 bluish tint. [The full report of Professor Langley's observations will 

 soon be published by the Army Signal Office.] {Nature, xxvr, 31G.) 



Desaius communicates to the Paris Academy of Sciences a memoir 

 on the distribution of heat in the dark regions of solar spectra with glass 



