642 TRANSACTIONS OP THE AMERICAN INSTITUTE. 



American Institute Polytechnic Association, ) 



January 4, 1867. ) 



Prof. S. D. Tillman, Chairman; T. D. Stetson, Esq., Sec'y. 

 The Chairman presented the following scientific summary : 



Functions of Leaves. 



M. Bonssingault, in a paper read at the French Academy of 

 Sciences, states experiments made, by him show that the under- 

 surface of the leaf decomposes considerably more carbonic acid 

 than the upper-surface, even when exposed to the direct action of 

 the sun's rays. In some instances he found the difference was as 

 4 to 1. 



Aluminium and Calcium. 



Wohler has recently succeeded in preparing an alloy of these 

 metals, by heating aluminium and sodium with a large excess of 

 chloride of calcium. The alloy is very lustrous, of a lead gray 

 color, and not tarnishable by either air or water. Its specific 

 gravity is 2.57, or slightly more than that of hammered aluminium. 



Aluminium and magnesium. 

 Wohler has made an alloy of these metals, by fusing equal com- 

 bining proportions or equivalents under a layer of common salt. 

 The alloy has the color of tin, and is very brittle. At a red heat 

 it combines with the oxygen of the air, and produces a flame 

 almost as brilliant as that of pure magnesium. 



Organic Eeiviains. 

 The polishing slate found in Bohemia has been computed to 

 contain, in every cubic inch, forty-one thousand millions of infuso- 

 ria. Since a cubic inch of this slate weighs 220 grains, in every 

 single grain there are one hundred and eighty-seven millions of 

 skeletons of silesious shields. This mineral, which may literally 

 be called the grave stone of extinct organisms, contains many mil- 

 lions more remains of microscopic animals than are found in the 

 same weight of chalk. 



Meteorology in America. 



The Chamber of Commerce of New York has now in operation 



at its rooms, Hough's wonderful self-recording barometer, which, 



by means of electricity, notes any change in the column exceeding 



one-thousandth of an inch, and, by the intervention of clock-work, 



