16 Examination of Minerals from Ava. [Jan. 



This natural litharge is readily fusible without effervescence, and 

 resembles, in the reddish brown colour it assumes, the vitreous coat, 

 which is always remarked upon the Dain and Yowetni silver cakes 

 from Ava : I had previously occasion to examine the composition of this 

 substance, which I had found to consist of 



Oxide of lead, 70.5 



Oxide of antimony, .... 12.2 



Oxide of copper, 10.0 



Silver, probably entangled in the slag, .... 6.0 

 Earthy matter, „ 1.3 



100. 



I at the time concluded, that the Burmese refiners made use of 

 antimony and lead in refining their silver, and that a little of the arti- 

 ficial slag remained attached to the surface of the silver upon its being 

 suddenly cooled before the litharge was entirely worked off. I have 

 been assured, however, that they use a natural ore to produce the 

 peculiar effect remarked ; and if so, the mineral now under description 

 must undoubtedly be the substance employed. 



It is worthy of remark, that the Burmese assayers judge of the 

 quality of silver by the crystallization of this coat, or rather by the 

 crystallization of the surface of the metal itself under its protection. A 

 star is the emblem formed upon their standard silver, which consists 

 nearly of the proportion of 1 atom, copper (10.5) to 5 silver (89.5). 

 It would be curious to ascertain whether this crystallization is a con- 

 comitant of other definite mixtures of the same metals. The Kharubdt 

 silver, containing 5 per cent, of copper, exhibits spiral circles of litharge 

 on its surface, in lieu of the star. 



10. — Platina Ore. In addition to our information respecting the lo- 

 cality of the platina ore of Ava, Major H. Burney has favored us, through 

 Mr. Swinton, with the following interesting particulars: 



" I find that a good deal of the platina ore is brought from some 

 mountain torrents or small streams, which fall into the Kyendieten 

 river from the westward, near a town called Kannee ; and it is collect- 

 ed in a very curious manner, as Mr. Lane is informed, although he hesi- 

 tates to believe the fact. The horns of a species of wild cow in this 

 country called T'sam, perhaps the same as the Nylgao of India, have 

 a velvet coat before the animal reaches the age of two or three years : 

 a number of these horns are taken and fixed in the beds of the small 

 streams, and at the close of the rainy season, when the water subsides, 

 a coth is put down over each horn separately - 3 and the horns, and cloth 



