134 Mr. Levi/ on a new Mineial. [Fr.n. 



derived frcm a prism with such dimension?!, there can be no- 

 doubt but that the indices of their decrements would lie very 

 complicated, when compared with those resulting from the ratio 

 of the edge h to the edge d, which I have assumed. Thus, 

 although the alleged property of oblique rhombic prisms may 

 really exist in the primitive forms of some substances, yet this 

 example proves that it is not of universal occurrence. 



i am sorry that I cannot add to the determination of the primi- 

 tive form of this substance, a satisfactory account of its physical 

 and chemical characters, but the quantity of it which I could 

 procure was so small, that no very decisive experiments upon it 

 could be made. Dr. Wollaston, however, to whom I never 

 applied in vain for assistance, was so kind as to examine a very 

 minute quantity of it; and he found it to contain the same prin- 

 ciples as datolite. It still remains to determine in what propor- 

 tion these are combined, if in the same as in datoiite, or as in 

 botryolite, or whether it differs from both in this respect. 



The mineral is sufficiently hard to scratch fluor spar, but it 

 will not scratch glass. I found an indication of cleavage, parnlle> 

 to a plane passing through the small diagonals of the bases of 

 the primitive prism. In one of the two specimens in which I 

 have observed it, it is mixed with carbonate of lime ; and in the 

 other, with the same substance, and with small Hat crystals of 

 apophyllite. 



Should it be found necessary to designate this substance by a 

 new appellation, when an exact and complete chemical analysis 

 of it shall have been made, I would propose to call it Humbold- 

 ite, from that eminent philosopher to whom natural science is 

 so much indebted ; and 1 hope that he would see, in the liberty 

 I had taken of associating his name with this new mineral, no 

 other motive, than my desire to evince the respect and gratitude 

 1 have for him.* 



I am, Sir, yours, Sec. 



A. Levy. 



* It may be useful to remark, tliut the name of Humboldt is already recorded in mine- 

 ralogical nomenclature; for the protoxalatc of iron found by M. Breithaupt in friable 

 lignite at Kolowserux, in Bohemia, has been denominated ffumboldtine by its analyst, 

 M. dc Rivero.— (See Ann. de Chim. xviii. 207, or Journal of Science, <Scc. xii. 488.) — 

 Edit. 



