Discovery of Yttro-Cerite in Massachusetts. 351 



" Chathamite. H. 55. G. 6-226. Mas. fine gran. Fract. un- 

 even. C. tin-white to steel-gray ; rarely tarnished ; bluish gray. 

 Streak grayish-black. (Lo. Chatham, Ct. cobalt-mine. Before the 

 blowpipe emits fumes of arsenic, and with borax gives a blue 

 bead. Arsenic, 70; iron, 17-70; nickel, 12-16; cobalt from 1-4 

 to 1-3 p. c.)" 



In this Journal, Vol. xxix, p. 242, Mr. Booth has given an anal- 

 ysis of an ore of nickel and cobalt, from Riechelsdorf, which gave, 

 nickel, 20-74; cobalt, 3-37; iron, 3-25; arsenic, 72-64, from which 

 he deduces the formula, (Ni,Co,Fe)As^ Now it is well known 

 that nickel, cobalt and iron may replace each other in any propor- 

 tion, and hence the hypothetical formula RAs^ may be used to 

 express the composition of lohite nickel, which is undoubtedly 

 the ore analyzed by Prof. Shepard, and here called Chathamite. 



From these few notes it will be seen how difficult it is to follow 

 out consistently the principles espoused by Prof. Shepard, and we 

 regret this the more, because few men in this country have culti- 

 vated mineralogy with equal zeal, activity and success. Ameri- 

 can mineralogy, in particular, is greatly indebted to him for many 

 personal explorations made with much labor and a wide range of 

 travelling. His tact in bringing out, fitting up, and arranging 

 American minerals is unrivalled ; but we cannot discern any valid 

 reason why we should insist on keeping closed one half the shut- 

 ters of an ill-lighted apartment, admitting the rays only through 

 the leaded diamond-glass of a single Gothic window. 



~ Yale College Laboratory, August 1, 1844. 



Art. XL — Discoveiy of the Yttro-Cerite in Massachusetts ; by 

 Prof. Edward Hitchcock, LL. D. 



(Read to the Association of American Geologists and Naturalists at Albany, 



April, J 843.) 



In looking over recently some neglected duplicates of rocks 

 and minerals collected many years ago in Massachusetts, my eye 

 accidentally fell upon one exactly resembling specimens of yttro- 

 cerite, which I had received from Sweden. It occurs in thin veins 

 running through granitic gneiss, and presents the peculiar and 

 striking purple color of the Swedish mineral. It corresponds also 

 in hardness and in structure ; and I have little hesitation in pro- 

 nouncina: them identical from these characters alone. Unfor- 



