670 



SCIENCE. 



[Vol.. n., Xo. 42. 



In criticising the current use of tlic word 

 ' light ' in physics, Professor Newcomb opened 

 a long and interesting discussion. He urged 

 that photometric measurements were compara- 

 tively valueless, because they estimate a part 

 only of the radiant energy of the sun ; whereas 

 the quantit}' which should be determined was 

 the number of ergs received per square centi- 

 metre. Professor Langiej-, however, asserted 

 that it would be impossible to estimate the 

 radiant energy received from the stars with our 

 present appliances : not all the stars combined 

 would produce deflection, even in so sensitive 

 an apparatus as the bolometer. 



Another feature of marked interest was Pro- 

 fessor Rowland's exhibition of photographs of 

 the solar spectrum, obtained bj'his new concave 

 gratings, hy which he had prepared a map of 

 the spectrum much more detailed than hereto- 

 fore secured, and free from the defects of scale 

 found in previous photographs. 



Professor Asaph Hall communicated the re- 

 sults of his researches upon the mass of Saturn, 

 based upon new measurements of the distances 

 of the outer satellites. He determines the 

 relative mass of the sun to that of Saturn to 

 be as 1 to -g^ja-- 



Professor Brewer took the occasion of the 

 academj^'s meeting in the city of his residence 

 to exhibit samples of his experiments of manj' 

 years' duration upon the subsidence of par- 

 ticles in liquids. Thej' showed the action 

 of saline and organic matter, of acids and of 

 freezing, upon the precipitation of sediments. 

 Most of the samples had been undisturbed for 

 five or six j'ears, and showed varying degrees 

 of opalescence, resulting from the suspension 

 of matter in the fluid. 



We have mentioned onlj' the more important 

 papers, or those which provoked a fuller dis- 

 cussion than usual. The following complete 

 list will show how largelj'' the physical side of 

 science predominated at the meeting. In as- 

 tronomy, besides the reports on the eclipse of 

 Ma3' 6, papers were read by A. Hall, on the 

 mass of Saturn ; by S. P. Langley, on atmos- 

 pheric absorption ; and bj' O. T. Sherman 

 (present b}' invitation), on personality in the 



measures of the diameter of Venus : in mathe- 

 matics, by S. Newcomb, on the theorj- of 

 errors of observation, and probable results : 

 in p7i?/sics, bj' S. Newcomb, on the use of the 

 word ' light ; ' by W. H. Brewer, on the sub- 

 sidence of particles in liquids ; and by H. A. 

 Rowland, on a new photograph of the solar 

 spectrum : in meteorology, bj* E. Loomis, on 

 the reduction of barometric observations to 

 sea-level: in geology, by T. S. Hunt, on the 

 Animikie rocks of Lake Superior; bj- J. D. 

 Dana, on the stratifled drift of the New-Haven 

 region ; bj' B. Sillimau, on the mineralogj' 

 and lithology of the Bodie mining-district ; 

 and bj' J. S. Newberrj-, on the ancient glaeia- 

 tion of North America : in chemistry, by W. 

 Gibbs, on phospho-vanadates, arsenio-vana- 

 dates, and antimonio-vanadates, and on the 

 existence of new acids of phosphorus : in 

 physiological chemistry, bj' R. H. Chittenden 

 (present by invitation), on new primary cleav- 

 age forms of albuminous matter : in paleon- 

 tology, by J. Hall, on the Pectenidae and 

 Aviculidae of the Devonian system ; and by 

 O. C. Marsh, on the affinities of the diuosauriau 

 reptiles : in anthropology, bj' A. G. Bell, on 

 the formation of a deaf varietj- of the human 

 race ; and by J. W. Powell, on marriage insti- 

 tutions in tribal societj'. 



The report of the committee on glucose, ap- 

 pointed by the president in conformity with a 

 request from the government, was accepted by 

 the academy-, and will be transmitted to Con- 

 gress with the president's report. This will 

 also embody- the proceedings of recent meetings 

 of the academy, the report of the committee on 

 alcohol, and that on the eclipse of the sun, 

 together with the thanks of the academy to 

 the secretarj' of the navy and the officers of the 

 Hartford for their co-operation in the expedi- 

 tion to Caroline Island. It wiU also include 

 an expression of the approval of the academ}' 

 of the eftbrts now making to secure a system 

 of uniform time. 



The next stated session of the aoademj- will 

 be held in "Washington in April next, and it is 

 probable that the following mid-j'car session 

 will be held in Cambridge. 



