Association of American Geologists and Naturalists. 127 



mate analysis of die several coals, he was enabled to bring to a test the 

 theoretical heating power assumed by European chemists. One interest- 

 log result which these researches tended to establish was, that the evap- 

 orative power is dependent on the carbon constituent of coal. Six dif. 

 ferent coals, of very different constitution, were cited as affording proofs 

 of this law of heating power. 



He stated that those who have sought to determine the heating power 

 of fuel (or practical purposes, hv fnmnntin nM ™ M(0 i,. + k~ u„„.: 



ers of pure solid carbon and that of hydrogen gas, seemed not to have 

 taken into account the amount of heat already in a latent state in the 

 latter material, as used by chemists to determine its heating power, while 

 « fuel the material itself is in either a solid or liquid state. In illumi- 

 nating gas, (which may be used for heating purposes,) the hydrogen has 

 been rendered gaseous by the agency of a large amount of fuel, burned 

 under the retort. It was stated that the practical bearing of this differ- 

 ence becomes the more important in cases where the products of com- 

 mon necessarily pass away from the surfaces to be heated at a tem- 

 perature above boiling point. The vapor of water thus escaping has 

 e same bulk as the hydrogen from which it has been generated, while 

 oxygen which had been condensed in forming it possessed only one 

 J that bulk. On the other hand, the oxygen, which, with the carbon 

 ^ uel, forms carbonic acid, is unchanged in volume. The carbon may 

 Jjnsequently be considered as undergoing no effective enlargement 



ford" 6d int ° that acid ' ln the caIorimeters of Lavoisier and Rum- 

 sed ! m ° reover ' tne w atery vapor generated from hydrogen was conden- 

 y employing cold surfaces, capable of absorbing the latent heat of 



the 



gases. 



Dr 



j • w * ■*"• JLnnney, u was resoivea 10 rescind tne reso- 



Pro° n ? aSSecl ,ast y ear relative to the election of officers, and to 

 ceed at once to the discharge of that function, 

 ne officers for 1845 were then chosen by ballot. 

 to * t "i <x ' m > B. Rogers was chosen Chairman. 



• • Silliman, Jr. and Dr. J. Lawrence Smith, Secretaries, 

 .y' D H°"ghton, Treasurer. 

 trib \\ ^' Hayes read a " Report on the Geographical Dis- 



a r on anu * Phenomena of Volcanoes," prepared in pursuance of 

 ^solution of the Association of last year. 



w ith • f Xamine< * m »nutely the geographical distribution of volcanoes 

 tion rence to determining the great lines of their geognostic posi- 

 Wr i" onstra ted that their position was determined by the con- 



nuiJ f°i, l ' le crust ot * tne eartn i anQ the outlines, extent and conti- 

 y °t the great continental masses. 



> 



