222 Andres del Rio on Silver Ores, 



pare the tables of errata, and it will be found that the English 

 is a mere translation of the Latin table given by Vlacq. This 

 clearly proves that it was never intended for any reprint of the 

 work which Miller might have had executed in England, but 

 only to assist the mere English reader in the use of the Dutch 

 publication. This certainly was an assistance to the circula- 

 tion of what might be considered in some measure as a pirated 

 book, but does not amount to a substantive act of piracy in 

 itself. 



Art. VI. — Silver Ores reduced by the Method of Becquercl. 

 By Andr.es del Rio. (Read November 5, 1 830.) Commu- 

 nicated by a Correspondent. 



I have the honour to present to the American Philosophi- 

 cal Society, the result of some curious researches, which in more 

 dexterous hands may become interesting. They were sug- 

 gested to me by the beautiful experiment of M. Becquerel, 

 inserted in the Annales de Chimie et de Physique for Septem- 

 ber 1829- He introduced into a glass tube some carburet of 

 sulphur, with a solution of nitrate of copper, which, being of 

 less specific gravity, floated upon its surface ; and by means 

 of a copper wire he established a communication between the 

 two liquids. He observed that the surface of the wire became 

 coated with protoxide of copper, whilp small tables, assuming 

 a metallic and glistening appearance, w >re deposited on the sides 

 of the glass tube. These M.Wohler has since shown to be formed 

 of sulphuret of copper ; whence he considers the method of 

 Becquerel as being merely "a new mode of forming sulphurets, 11 

 to which, I think, he should have added, " by the decomposi- 

 tion of other sulphurets. " Indeed, I introduced severally into 

 three small glass tubes, some small lamella of ductile and some 

 fragments of brittle silver glance and red silver ore. These, 

 being exposed to the action of nitrate of copper and a copper 

 wire, were reduced in eight days to the state of metallic silver. 

 I repeated the experiment on the ores in small fragments, 

 which became coated with silver in five days. The formation of 

 silver was even apparent on the second day at the points in 

 which the ore came in contact with the glass. By what pro- 



