121 
From this it appears that his attention had been directed 
to it forty years before at Plattsburg, N. Y. Ice is com- 
posed of a congeries of prismatic crystals, whose axes are at 
right angles to the surface of the mass. “Examinations then 
and afterwards made of floating fresh-water ice have shown 
that the natural effect of the advancing year is gradually to 
transform ice, solid and apparently homogeneous, into an 
aggregation of these irregular prismatic crystals, standing in 
vertical juxtaposition, having few surfaces of contact, but 
touching rather at points and on edges, and kept in place 
at last merely by want of room to fall asunder. Until this 
ge has somewhat advanced, the cohesive strength of ice 
of considerable thic! is still adequate to sustain the weight 
and shock of the travel it had borne during the winter, but 
becoming less and less coherent by the growing isolation of 
the prisms, or more and more ‘rotten’ as the phrase is, though 
retaining all its thickness, the ice will at last scarcely support 
4 small weight, though bearing upon a large surface; the foot 
of man easily breaking through, and very slight resistance 
being made to the point of a cone.” The points of contact 
of the particles being destroyed, each will drop into the po- 
sition in the water below required by the place of its own 
centre of gravity, — that is to say, it will be upon its side, ex- 
posing large surfaces to the action of the warm water. With 
the ice in such condition, a heavy wind will cause the dis- 
Tuption of the particles and the speedy disappearance would 
be the consequence. This remark of General Totten as to 
the crystallization of ice has since been extended to nearly all 
substances, which in becoming solid assume the crystallized 
form. The axes of the ersytals tend to assume @ position at 
right angles to the surface of cooling. 
As illustrative of the mind of General Totten, it may be 
stated, that he seldom failed to give valuable hints for the 
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