CHEMICAL SCIENCE. 175 



warmed, a disengagement of hydrogen takes place, the oxide becomes 

 first blue, and is afterwards transformed into white titanic acid. 



ON THE STRUCTURE OF LAKE SUPERIOR COPPER. 



AT a meeting of the American Academy, in January, Dr. A. A. 

 Hayes stated, that, from extended observations, embracing more than 

 five hundred specimens of the Lake Superior native copper, no instance 

 occurred in which the slightest indication was presented of this copper 

 having been fused in its present condition. He had investigated its in- 

 ternal structure, by a new method of analysis, which permits all alloys 

 and foreign matters to fall on one side, while the pure copper is sepa- 

 rated and weighed as such on the other. In this way, and by little 

 modifications, the highly crystallized structure is exposed to view, the 

 less regularly polarized portions being removed. Whether we subject 

 the solid thick masses, or the thinnest plates, to the operation, one con- 

 stant result is obtained ; that this copper has taken its present varied 

 forms of crystallized masses, more or less flattened, laminated, or 

 grooved, by the movement among the parts composing the rocks in which 

 it is found. If we select a mass which has entered a cavity, we find 

 the crystals with their angles sharp and uninjured, while the mass 

 mainly may have been compressed into a plate. Dissecting this, the 

 crystals are seen to be connected with and form parts of the original 

 system of crystallization. Flattened and grooved specimens often pre- 

 sent on their edges arrow-head-shaped forms, derived from regular 

 crystals, crushed and laminated. 



PROCESS FOR REFINING GOLD. 



PROF. JAMES C. BOOTH has patented an improvement in processes 

 for refining gold, which is thus described in his specification. " The 

 nature of my invention consists in the preparation of a solution of gold, 

 alloyed with silver or other metals, so as to convert them into chlo- 

 rides ; and a precipitation of metallic gold upon the chloride of silver 

 and other insoluble chlorides; and in the subsequent reduction and ex- 

 traction of the silver or other metals from those insoluble chlorides ; or 

 the direct extraction of their chlorides by solution in the manner here- 

 inafter set forth, so as to leave the gold pure." Among the claims is 

 one for the process of dissolving alloyed gold for refining it, by devel- 

 oping nitric acid, or both nitric and muriatic acids, gradually from their 

 salts, in the manner set forth. 



SILVER IN METALLIC MINERALS AND THE PROCESSES FOR ITS 



EXTRACTION. 



MESSRS. MALAGUTI and DUROCHER presented to the French Acad- 

 emy, on Dec. 10, 1849, papers giving an account of some very careful 

 examinations made by them on the association of silver with the me- 

 tallic minerals and the best process for its extraction. They com- 

 mence by referring to some previous researches upon the metallic sul- 



