1847.] Association of Geologists and Naturalists. 215 



the strife should radiate, we have only to suppose a considerable 

 accumulation of snow in the northern latitudes, for a long period; 

 different quantities of water would fall on this snow, from different 

 temperatures, in its vast extent from north to south, which would 

 produce a general movement of the glacier in one direction, and 

 explain the uniformity of the stria of America. 



After adjournment, many of the members visited, by invitation, 

 the house of Francis Alger, Esq., and were afforded an opportu- 

 nity of examining his splendid collection of minerals. 



Saturday Morning — Final Session. 



Prof. Johnson made some remarks on the construction of geo- 

 logical sections; in which, in order to get the true color, he pro- 

 posed to use the powdered rock itself, fixed by a solution of gum 

 arabic. 



He read a report on the incrustations of steam boilers, which 

 are so very troublesome in sea steamers. The proportion of in- 

 crustation is very different in different sea water. In the scales 

 from the boiler of a sea steamer, as examined by him, sulphate of 

 lime was the principal ingredient; in that obtained from the wa- 

 ters of the Schuylkill, it was chiefly the carbonate of lime, with 

 very little sulphate. 



Count Pourtales read a memoir on the Structure of the Holo- 

 thurida, accompanied by specimens, with description of a new 

 species, and remarks on the species hitherto found on the coast of 

 New England. 



On motion of Com. Wilkes, a committee was appointed to 

 communicate with the Secretary of the Navy, on the subject of 

 deep sea soundings by our national vessels. 



Prof. Emmons read a paper on the distribution of inorganic 

 matter in forest and fruit trees. 



On the Distribution of the Inorganic Matter of Forest and Fruit 

 Trees, by Ehenezer Emmons, Jilbany, JV. Y. 



The object of this paper is two-fold. 1. To show what kinds 

 of inorganic matter exist in the ash of trees. 2. How the several 

 elements existing in the ash are distributed through the parts and 

 organs composing the individual tree. 



The object of the paper was illustrated by a few examples only 

 of the analyses which had been made. 



The following are copied from the paper, for illustration of the 

 mode of treating the subject: 



