planes visible, indicating layers or lamination, in the ong 
structure. A thin film of matter followed each newly f 
crevice downwards, and bubbles of air rose continually thro 
the same to the surface. These planes of division conver 
below, giving the block the appearance above represented, 
verted spikes or rudely formed pyramids, with their bases upwe 
v ten o’clock A. M. the upper half of the block was di 
in this manner. The figures were somewhat regular 
crease of temperature. I presume that this appearance cal” 
thus accounted for. No doubt the planes of division exist” 
the solid ice, as results of the crystallization in freezing. 7” 
general law of structure in all masses slowly crystallizing 
a state of fusion is the production of a prismatic struct 
peas to the cooling surfaces. Basalt assumes its po! 
gures in obedience to the same law, and the structure © 
quite in accordance with it. Its effects are not wanting ev ‘ 
some pastes, like starch and domestic cake. yi 
This structure exists often where it is concealed. An]? 
block tin shows no crystalline structure, but by slow fast 
q 
3 
i 
