1854.] 23S 



(no other examination having been made of it.) as doubtful. I received, through the 

 kindness of Dr. J. L. Le Conte, a genuine and perfectly pure piece of the mineral, 

 which I have carefully examined. The physical properties of it agree very well 

 with those given by Herrera ; with regard to its chemical composition, Herrera 

 has the merit of having correctly discovered in it the presence of carbonic acid ; 

 Del Rio, that of having found in it the oxide of zinc. With regard to the other 

 constituents, both were mistaken. A qualitative analysis has shown that this 

 mineral contains carbonic acid, oxide of zinc, oxide of copper, oxide of man- 

 ganese, magnesia and lime, but no traces of any other substance. The quanti- 

 tative analysis was made with the usual methods. 



B. B. in a tube it blackens and does not give any " sublimate, which condenses 

 in transparent drops," (as Herrera stated,) but none at all. Upon charcoal in the 

 R. F. it blackens, and covers it with white incrustations, having a steel-blue 

 margin, which are yellow as long as hot ; and which, when moistened with 

 cobalt solution and re heated, become green. The mineral itself does not become 

 green, but brownish black ; and after having received a good reducing heat, it 

 shows under the magnifier, and when powdered in an agate mortnr, metallic 

 copper. With borax, it gives distinctly the copper reactions. Dissolves in acids 

 slowly, with effervescence. After weighing, I have carefully examined all the 

 separated substances for their purity, but neither traces of tellurium, nor those of 

 cobalt and nickel, could be detected. 



0.6226 grs. of the mineral gave: 



0.3783 grs. of oxide of zinc, or . . . 60.76 p. c. Zn ; 



0.0137 " " oxide of copper, or . . 2.20 " Cu O ; 



0.0062 " " protosesquioxide of manganese, or 0.93 " Mn O ; 



0.0025 " " pyrophosphate of magnesia, or 0.14 " Mg O ; 



0.0092 " carbonate of lime, or . . 0.83 Ca O. 



Herrerite is, therefore, nothing else but a cupreous Smithsonite, and its com- 

 position the following: 



Carbonate of zinc, 



copper, 

 manganese, 

 magnesia, 

 u lime. 



ei u 



a u 



93.74 per cent, 

 3.42 " 



1.50 " 

 0.29 " 

 1.48 " 



100.43 



Chemical Notices. 



"By Charles M. Wetherill, Ph. D., M. D. 



On the occurrence of Gold near Reading. In a paper upon the occurrence 

 of gold in Pennsylvania, read before the American Philosophical Society, and 

 published in vol. x. of their Transactions, 1 alluded to an auriferous quartz in 

 the neighborhood of Reading, Pa., and the examination of which afforded me 

 slight, through uncertain traces of gold. I stated at the close of the article, that " I 

 had no doubt that a more careful examination of the rocks in the vicinity, would 

 yield affirmative results in an examination for this metal." The views then expressed 

 have proved to be correct. Last summer, Mr. Philipps, a mining geologist, in 

 searching for iron ore on the farm of Mr. Entlicb, a few miles eastward from 

 Reading, and of Mr. Jonathan Deininger, about a mile from the same place on 

 the western slope of Penn's Mount, detected gold by washing specimens of the 

 ferruginous quartz. I called upon Mr. Deininger, who showed me the specimens 

 in his possession, and gave me some of the quartz rock from his farm. Mr. I ein- 

 inger showed me a specimen of gold, in weight I should judge between one and 

 five centigrammes, which was broken by himself out of the rock. 



