818 Intelligence and Miscellaneous Articles. 



nished large quantities of pyrites, which I believe also to be free 

 from arsenic ; but of this I cannot speak so positively. It would be 

 an interesting subject of investigation at the present time, and 

 very important as bearing upon the question discussed by Pro- 

 fessor Davy, what ores of sulphur do, and what do not contain 

 arsenic. 



The Professor states that an inferior kind of brown acid is manu- 

 factured for manure purposes ; whereas all sulphuric acid as it comes 

 from the chambers is brown, whether made from brimstone or pyrites. 

 The colourless acid is produced by distillation from either, in order 

 to concentrate it. As, however, this process increases its cost with- 

 out improving its quality for many purposes, it is in such cases dis- 

 pensed with, and used either as it comes from the chambers, or 

 slightly concentrated by evaporation in open leaden pans at a low 

 heat, and is always brown. The colour, therefore, is no criterion of 

 its quality, except as to its per-centage of real acid. 



■ Henry Scholefield. 



Newcastle-upon-Tyne, 



September 19, 1859. 



ON THE OCCTTRRENCE OF GOLD. BY DR. F. A. GENTH, 



Much has been said and written about the occurrence of gold in 

 veins and elsewhere, and the formation of the same ; but, comparing 

 the different theories with some very important facts, we are often 

 at a loss to explain the latter satisfactorily, and it seems to me that 

 we know but very little about this difficult subject. Without any 

 intention to discuss the merits of the different theories, I will give 

 in the following a few data which may help to throw some light on 

 this question. 



Gold is frequently found in diorite (in smaller quantities in syenite 

 and granite) ; and although it is only rarely observed in the massive 

 rocks, I have seen specimens from Honduras, C. A., where it was 

 imbedded in the diorite without any other association. The result 

 of the complete decomposition of the diorite is generally a red 

 clayish soil, and this has in the gold region of North Carolina, &c. 

 a high reputation for its richness in gold. It was in the diorite 

 region of Cabarrus County, N. C, where the first large piece of gold 

 was found, weighing twenty-eight pounds. All this soil is more or 

 less auriferous, but containing the gold somewhat concentrated, 

 nearly in the same ratio in which the lighter particles have been 

 washed away. But not in this country only has the diorite been 

 found to be auriferous, as is proved by the large piece of eighty-six 

 pounds which was found at Alexandrowsk near Miask in Siberia, 

 y feet below the surface, in diorite. 



The gold obtained from the disintegrated diorite is generally 

 smooth and rounded, as if it were water- worn. This cannot be, how- 

 ever, because it lies still in its original, but only altered matrix, and 

 has not been subjected to any attrition by water and sand ; besides. 



