77 



1788; and the other discovered in Siberia, and described by Pallas. 

 This latter the Tartars consider as a sacred relic which had descended 

 from heaven. 



II. For the descriptive part of the four stones which have been 

 analysed by Mr. Howard, we are indebted to the Count de Bournon, 

 who observes in general, that none of them are, or appear ever to have 

 been, of any regular shape ; and that when entire they are all coated 

 with a black crust, the thickness of which however is very incon- 

 siderable. The Benares stone being that which has the most striking 

 mineralogical characters, obtained the preference in these descriptions, 

 and served as an object of comparison in the account to be given of 

 the others. The crust already mentioned, which is common to all, 

 is of a deep black colour, and of an uneven surface. It strikes fire 

 with steel, and frequently contains particles of native iron. The stone 

 itself when broken is of a grayish ash- colour, and of a granulated 

 texture: it appears evidently to be composed of four different sub- 

 stances; one of them, which is in great abundance, shows itself in the 

 form of small spherical bodies of various sizes, of a gray colour, some- 

 times inclining to brown, perfectly opake, and so hard as to give 

 faint sparks when struck with steel. Another of these substances 

 is a martial pyrites, of a reddish yellow tinge, somewhat inclining to 

 the colour of nickel. When powdered it is of a black colour, and not 

 attractable by the loadstone. The third substance consists of small 

 particles of iron, in a perfect metallic state. These, although they 

 compose only about -sVth part of the whole stone, give, however, to 

 the whole mass the property of being attractable by the magnet. 



These three substances are united together by means of a fourth as 

 a cement, which is nearly of an earthy consistence, and of a whitish 

 gray. The specific gravity of the aggregate stone is 3352. 



The constituent parts of the stone from Yorkshire are exactly the 

 same as those of the above, except that its grain is finer, that the 

 globules are more irregular in their shape, that the martial pyrites is 

 in less, and the iron in greater proportion, and that the earthy cement 

 is more compact. Its specific gravity = 3508. 



The Sienna stone was more similar to that from Benares than the 

 last mentioned ; the particles of iron were in a somewhat greater 

 proportion. It contained some particles of black oxide of iron; and 

 likewise one single globule of a vitreous substance, of a pale yellow 

 colour inclining to green, and of a hardness rather inferior to that of 

 calcareous spar. The specific weight of the aggregate was =3418. 



Lastly, the stone from Bohemia was most similar to that from 

 Yorkshire, except that it appeared to be totally free from any par- 

 ticles of pyrites, and on the other hand to have a much larger pro- 

 portion of globules of native iron; many of which, perhaps, on account 

 of the stone having remained longer in the earth, had undergone a de- 

 gree of oxidation on their surfaces. Its specific gravity was = 4281. 



From these descriptions we learn that these stones, though they 

 have not the smallest analogy with any of the mineral substances 

 already known, have a very peculiar and striking resemblance to each 

 other ; a circumstance surely which must excite the attention and 



