Association of American Geologists and Naturalists. 105 



* 



bear this fact in mind, as he might in his researches fall in with the 

 path of some ancient Unio. 



o 7$ o'clock in t 

 7£ o'clock, P. M. 



Prof. 



D. Bache, inviting the Association to call at the office of the 

 Coast Survey, and see the instruments and work. 



Prof. H. D. Rogers submitted a communication on the prob- 

 able constitution of the atmosphere at the period of the forma- 

 tion of the coal. He stated that the recent researches of Ameri- 

 can geologists, by informing us of the true quantity of coal in 

 North America, enables us for the first time to estimate with 

 some precision its total amount on the globe, and thereby to 

 compute the quantity of carbonic acid which the ancient atmos- 

 phere must have contained to supply this vast body of carbon. 

 He showed that the existing atmosphere contains, in its carbonic 

 acid, carbon enough to furnish, through vegetable action, about 

 oo0,000,000,000 tons of coal j and that the probable quantity of 

 coal in existence, all of which must have bee'n elaborated from 

 the ancient atmosphere, is nearly 5,000,000,000.000 tons, that is 

 t0 s ^' about six times that which the present atmosphere could 

 Produce. So great a reduction in the carbonic acid of the earth's 



osphere, implying, as all chemists are aware, a corresponding, 

 augmentation of oxygen, is a fact of great interest to geology, 

 as showing that very modification in the constitution of the air 



h'oh° W0U ^ a( * a Pt it t0 tne development of animals progressively 

 o er in the scale of organization, which are known to require 

 ^°re rapid oxygenation of their blood. 

 ,0 J- rV. B. Rogers communicated an abstract of a paper re- 

 g to the chemical equivalents of certain substances, as in- 

 ured from recent experiments by Prof. R. E. Rogers and him- 

 • deferring to the progress of investigation in this funda- 

 branch of chemical science, he called attention to the 

 n admirable researches of M. Dumas and other European 

 , ' > as giving strong confirmation to the doctrine maintain- 

 all I • ^ rout ' °f England, that the equivalent numbers of 



tnical substances are whole numbers, taking hydrogen as 

 d k P'°y' n S the apparatus for the analysis of carbonates 



S 



the 



. ldl > tie stated the following as some of the results: 

 ^equivalent of lime 28, that of baryta 72, that of soda 31. A 



" XLT,I » No. l._Anril-.T.mo ^fiAA 14 



April-June, 1844. 14 



