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ART. X. — Relation of Atomic Heat to Crystalline Form. 

 By J. Aitken Meigs, M. D. 



Very probably in the atomic constitution of matter we are to seek the true material 

 basis of the whole Science of Nature. The unity of Natural Science — as displayed 

 in the mutual relations and connections of its different parts — here finds a positive 

 expression. Therefore, Natural Science, as a unit, becomes philosophically intelligible 

 in proportion to the clearness and accuracy of our views concerning the aggregation 

 of passive atoms or ultimate particles into Forms, — whether organic or inorganic, 

 whether specifically or generically impressed. But the comprehensive study of such 

 aggregations, requires the contemporary investigation of the physical agent which 

 brings together inert atoms and retains them in contact, — which preserves as well as 

 produces the form. 



Under the influence of the attractive principle, matter everywhere tends deter- 

 minedly to assume a definite shape. Hence crystallization is perceived to be as 

 common a characteristic of the inorganic, as vitality is of the organic world. Yet if 

 we may judge from the standard works of the day, upon these subjects, the cause of 

 the one is involved in as much obscurity as that of the other. 



A crystal is inanimate matter individualized, or endowed with a form, in virtue of 

 which it approximates the unorganized to the organized kingdom. The difference 

 between the most complex crystal and the simplest plant is of course extreme; but 

 while on the one hand physiologists have carefully detailed these differences; on 

 the other, they seem to have lost sight of the striking analogies which exist between 

 the seriate results produced alike in the crystalline and the animal and vegetable 

 worlds, by a methodical intermittency of action, on the part of their respective 

 developing agents. Thus the concentric layers of wood in the trunk of a tree, between 

 which lines of demarcation are more or less evident, — as is especially the case between 

 the duramen and alburnum of the lignum vitse and the coco-wood, — indicate the 

 successive periods of activity and repose of the formative principle. So the lines of 

 cleavage in a crystal silently assure us that the attractive power is intermittent in 

 action, and that along these weak planes it had ceased its exertions for a while, or, 

 at least, had acted very feebly.* Among the numerous and beautiful forms assumed 



* Dana. Amer. Journ. of Science and Arts, 2d ser., vol. iv , p. 378, —v., p. 100. 



