3d4 



Analysis of Scientific Books. 



Fahlun, between two or three ardent collectors at an auction, till 

 the price of the precious lot ran up enormously ; whilst, from its 

 perfect resemblance to some we had once an opportunity of exa- 

 mining, we felt confident, that it was quite guiltless of concealing a 

 particle of selenium in its whole composition. The pyrites usually 

 said to be seleniferous, is of a bright yellow colour, a small grain, 

 and generally very friable. 



As a specimen of the elaborate figures which accompany many 

 of the descriptions, we annex a copy of that which Mr. Phillips 

 has given of Humite *. We have selected this mineral for our pur- 

 pose, because, — I St., its form has never been described before. 2dly, 

 Count Bournon, in his Catalogue, says that all its planes are 

 striated, whereas not one of them is so ; for what he mistook for 

 strice, are, in fact, so many planes, as has been proved by sub- 

 jecting the crystals to the reflective goniometer. 3dly. It shews, 

 therefore, the value of that instrument in a striking degree, and 

 that the use of it quickens the sight of the observer, who, while 

 measuring without a glass, finds planes, where an old, and generally 

 supposed accurate, observer saw only striae. 



Humite. — Bournon. 



It occurs in very small crystals, which are of a deep reddish- 

 brown colour, and transparent or translucent, with a shining lustre. 

 The crystals are modified in an extraordinary degree; their primary 

 form may be considered as being a right rhombic prism, of 60° and 

 120°, but they yield to mechanical division, parallel only to its 

 shorter diagonal: (i. e., to the plane h of the following figure.) 



Primary. 



i-Jumite. In honour of Sir Abraham Kume. 



