15 -A Intelligence and Miscellaneous Articles. 



drogen O H, with a limited amount of free hydrogen. The result 

 of his experience, however, seems to establish the statements already 

 made, as may be seen in a report of the Commissioner of the Society 

 for the Encouragement of Industry, &c, to whom the subject was 

 referred. — Silliman's Journal, September 1851. 



ON THE CRYSTALLIZATION OF SULPHUK. BY CH. BRAME. 



Since the time that Mitscherlich demonstrated that melted sulphur 

 crystallized in oblique rhombic prisms, and confirmed Hauy's state- 

 ment that sulphur, dissolved in bisulphuret of carbon, crystallized 

 out in rhombic octohedrons, the opinion has been entertained that 

 sulphur crystallizes in oblique prisms after melting, in octohedrons 

 with a rhombic base from a solution, and that the prismatic sulphur 

 becomes opake on account of the gradual assumption of the octahe- 

 dral structure. 



The author now shows in his paper that rhombic octohedrons are 

 produced by the influence of mechanical subdivision, the removal by 

 means of steam of several bodies which also act mechanically upon 

 melted sulphur. A temperature of 122° F. produces them in the 

 utricles of sulphur (utiicules de soufre). At 212° F. small soft 

 utricles (dendrites) are converted into rhombic octohedrons, as well 

 as a part of the vesicles. 



On the contrary, prismatic plates are always formed, however 

 thin the stratum of melted sulphur may be ; as, for example, that 

 which is deposited upon a glass plate when sulphur vapour at 392° F. 

 condenses slowly. These c^stals are generally right rhombic 

 prisms ; but as soon as the stratum becomes only a little thicker, 

 the crystals obtained are oblique rhombic. 



According to the author, sulphur crystallizes in oblique prisms 

 from the melted state only when an excess of fluid sulphur is present, 

 however thin the stratum may be. In the opposite case, the true 

 or modified octohedron presents itself. 



By subdivision the melted sulphur may be separated into a multi- 

 tude of minute drops, which from solidifying upon the surface become 

 covered with a more or less thick crust. If this is very thin, 

 the drops of sulphur are converted into utricles. If it is thicker, 

 the sulphur drops are more or less regularly flattened by pressure, and 

 there results instead of an utricle a flattened drop with a quadratic 

 basis, which is or is not modified at its corners, and appears altogether 

 like a considerably modified rhombohcdron. The extremely thin 

 coats of melted sulphur which are obtained by vaporization appear 

 to explain, by their behaviour described above, how it is that any 

 given pressure acts : it always produces a right rhombic prism. The 

 rhombic octohedron appears, on the contrary, to be formed when 

 that crust has become so thick that it is capable of resisting the 

 pressure ; and then there is a pressure upon the interior mass, and 

 a contrary pressure upon the interior surface of the drop ; the cry- 

 stalline form which is assumed under such conditions is the rhombic 

 octohedron. 



