1885.] 47 [Gentb. 



It occurs as a crystalline coating or in minute somewhat globular aggre- 

 gations, of a pale green to a rich apple-green color, in limestone associated 

 with niccolite. It is frequently associated with aragonite in fine needle- 

 shaped crystals, which often give it a superficial coating. I was able to 

 obtain a small quantity of a state of fair purity, slightly contaminated with 

 aragonite. After treating it in the cold with very dilute hydrochloric acid, 

 to dissolve the aragonite, I had 0.0722 grm. for analysis, which gave : 



H 2 = 23.94 



NiO = 32.64 



CoO = 0.50 



MgO = 3.74 



CaO = 3.51 



As 9 0, = 36.64 



100.95 



20. Dr. Clemens Winkler and Herderite. 



Dr. Winkler published (Jahrb. Min., 1875, i, 172), a justification of his 

 work on herderite in which he says that my reproach that he had sacrificed 

 valuable material by the use of incorrect methods, is unwarranted and that he 

 must firmly repel it. 



I had intended to reply to Dr. Winkler, but really do not see any neces- 

 sity for it, because, he fails to show any error in my work, but only tries 

 to find excuses for his own shortcomings, and mentions experiments made 

 with apatite, a mineral with which herderite has no resemblance, either 

 physically or chemically. 



That the minerals from Ehrenfriedersdorf and Stoneham are identical, 

 as I have suggested, he now admits, and as this settles the main question 

 it would be a waste of words to say more about this matter. 



University of Pennsylvania, August 8, 1885. 



