390 Crystallization. 



least one side or other. Mr. D. then entered into a somewhat 

 elaborate inquiry into the differences vvliich should have appeared 

 had the primitive molecules of crystals been cubes and not 

 spheres; and some of his facts he admitted were favourable to 

 the former hypothesis, but more to the latter. In oljserving that 

 the crystalline masses formed at the bottom of the vessels by 

 spontaneous evaporation often presented very different geometric 

 figures, and totally dissimihir to the forms usually ascribed to 

 such salts by mineralogists, he was induced to consider the effects 

 of mechanical agency in the product of such anomalies. Notwith- 

 standing these and some other discrepancies, he is however in- 

 clined to consider Dr, Wollaston's theorv of molecular sphericity 

 as perfectly satisfactory, and the best adapted to explain the 

 phaenomena of nature. Mr. D. cou'-iders it an additioii:d i)roof 

 of the infinite wisdom of the great Author of nature, that the 

 molecules of our globe should have the same form as those al- 

 most incomprehensibly great orbs which appear in the heavens. 



LXXII. Intelligence and MisceUaneous Articles. 



CRYSTALLIZATION. 



XJr. J. R. CoxE has made some experiments on the crystalli- 

 iiation of salts, v/hich in some respects contradict the generally- 

 received opinions respecting that process. He found, contrary 

 to the notion of air being necessary to the consolidation of 07- 

 stals, that solutions of nitrate of potash, nuiriate of ammonia^ 

 and Glauber's salt, put into a phial at the boiling temperature, 

 and either corked or closely covered with a piece of bladder, fre- 

 quently deposited regular crystals as the mass cooled without 

 any exposure to the atmospheric pressure. On the other hand, 

 saturated solutions of these salts remained uncorked and exposed 

 to the atmospheric pressure dining three days without any con- 

 solidation. These experiments have been varied and repeated 

 in different sized vessels, and always with the same anomalous re- 

 sults. Nor did any material difference appear when the water was 

 fully saturated, or only charged with the salts. Solutions of these 

 salts even on shaking sometimes did not immediately crystallize, 

 while at others they yielded crystals without any apparent cause. 

 Sometimes he had regular transparent crystals two inches long ; 

 in other instances, only irregular masses at the bottom of the 

 vessel. All the rapidly- formed crystals, as might be expected, 

 were spongy, soft, striated, and had a satin- like aspect; and 

 the hasty crystallization always began at the surface. While in 

 some cases regular crystals were formed at the bottom of both 



corked 



