Prof. Vannxeni on iJie Mar»)o//te of Mr. XiUtall. 89 



it will be sufficient for my purpose to quote two authorities, 

 Haiiy and Mr. Brochant : the former considered it as a rock, 

 and hence it has no place in his mineralogical method ; and 

 by the latter it was (improperly) arranged (1819) as a sub- 

 species of talc, under the name of Talc esqidlleux, i. e. scaly 

 or rather splintery Talc. 



From the difference of opinion with respect to the rank and 

 place which serpentine ought to hold in our mineralogical 

 systems, it is really a desideratum that all obscurity upon this 

 subject should be removed, serpentine being important from 

 its gi-eat abundance, and the many uses to which it is and 

 may be applied. The object of this communication is to 

 make known the real character of serpentine, which the writer 

 believes he has ascertained, and submits his views with all due 

 deference to the Academy. 



It is to Mr. Nuttall, whose zeal and talents as an observer 

 of nature are well known, and whose contributions to natural 

 history have already been so respectable, that we owe the in- 

 trcKluction of a mineral to our notice, which in my opinion 

 throws such light upon this hitherto obscure subject as to en- 

 able us to assign to seipentine its proper place in the systems 

 of mineralogy, and thereby to remove a part of the conflision 

 existing in that almost, as we might say, chaotic science. 



The marmolite, the mineral alluded to, possesses those ex- 

 ternal characters which are acknowledged by all mineralogists 

 to be typical of a species ; and is moreover unifoiun in its com- 

 position, as ascertained by the analysis of specimens from two 

 localities that are nearly two hundred miles from each other ; 

 and has the same analogy to serpentine that all the lamellar 

 or crystalline minerals have to their compact varieties. 



The description which Mr. Nuttall has given of marmolite 

 is as follows: " The texture is foliated, with the laminae thin, 

 and often parallel, as in diallage. Sometimes also cleaving 

 in two directions parallel to the sides of an oblique and com- 

 pressed four-sided prism. These laminae, sometimes a quar- 

 ter of an inch broad, are commonly collected into radiating or 

 diverging clusters, of a pale green or greenish gray colour and 

 a pearly submetallic lustre, soft enough to be easily cut by a 

 knife, and almost perfectly opaque, indexible, and brittle. Its 

 powder is unctuous and shining. By the influence of the 

 weather it becomes whitish and more brittle. Its specific 

 gravity by Nicholson's balance was 2*4-70." 



" Chemical Characters. — Before the blowpipe it decrepitates, 

 hardens, and slightly exfoliates witliout showing any signs of 

 fusion." 



Vol.65. No. 322. Feb. 1825. M To 



