364 /. D. Dana on Cohesive Attraction. 



was of very large dimensions, and rose to the height of the clouds, 

 so that the spray elevated mechanically from the lake, was united 

 with the condensed vapor of the clouds in the same column. 

 The only danger therefore to he apprehended by a vessel from 

 the passage of a water-spout, arises from the whirl, which often 

 exhibits great violence. The whirlwind might prove destructive 

 to a vessel, while the water which it carries with it might be 

 barely sufficient to wet the deck. 



Art. XXXIII. — On Certain Laws of Cohesive Attraction; by 



James D. Dana. 



Read before the American Association of Geologists and Naturalists, held at 



Boston, September, 1847. 



From the account of cohesive attraction in works on Chem- 

 istry, we gather little more than what the term itself implies ; 

 and in the higher treatises on Physics, the subject is discussed on 

 general mathematical principles, and mostly without reference to 

 observed facts, excepting those of the most obvious character. 

 This is especially true of the attraction in solidification. I propose 

 to consider what observation teaches on this subject, and would 

 ask the attention of the Association to a brief statement of a series 

 of facts, and to certain obvious inferences from these facts. 



rhe objects to which we appeal for illustration, are the rocks 

 and minerals of the earth, and the ordinary forms of inorganic 

 matter. The grand principle has already been recognized, that 

 solidification and crystallization are the same process. As early 

 as 1807, in the Lectures on Natural Philosophy by the learned 

 J nomas Young * this philosopher says, after some explanatory 

 remarks, " It appears, therefore, consistent both with reason and 

 experience, to suppose that a crystallization more or less perfect 

 is the universal cause of solidity." Biot in his Precisf recognizes 

 the same principle j and other names favoring this conclusion 

 might be mentioned. The fact is obviously exemplified in nearly 

 every inorganic solid around us. The freezing of water is known 

 to be its crystallization, and snow is crystallized vapor. The 

 coarse-grained structure of bar-iron is correctly called its crystal- 



line structure: 



crystallization ; and m steel we perceive the same texture, arm 

 may trace it through varieties, till the grains are too fine to be 

 distinguished. Granite and all igneous rocks are made up ol 



* Course of Leisures on Natural Philosophy and the Mechanical Arts, by Thoffl« 

 Young. Ml, 2 vols. 4to. London, 1807.' Vol. i, p. 628. . lfl 



t Precis fclemeotaire de Physique, 2 vols. 8vo. Paris, 1824. Vol J, p. » 



