278 PHILOSOPHICAL TRANSACTIONS. [aNNO I766. 



can give the justest idea. The lump, or nodule, of which these two specimens 

 are fragments, was so richly impregnated with tin, that though the best tin ore 

 in general, will not melt without flux, nor do 20lb. of black, tin usually produce 

 more than 14lb. of white, this melted without flux, and 20 oz. produced 18 oz. 

 of the purest tin. 



The 3d specimen, found the 17 th of July last, was found in a stream work 

 near the borough of Granpont; its weight between 11 and 12lb ; the native tin 

 was inclosed so securely, that, but for the extraordinary weight, it had passed 

 unnoticed. Within the crust, the metal was not in granules, as in the first 

 specimen, nor thin as a leaf, as in the 2d; but much more abundant, and in 

 some places more than an inch thick. The crust, inclosing this 3d specimen, 

 was certain stone of the quartz kind, very hard to break, and exactly the same, 

 to all appearance, with that of the first mass. 



Thus far is the relation Mr. Borlase gives; but as the existence of native tin 

 is so universally doubted, Mr. Da Costa thought it necessary, that other proofs 

 than a mere historical account, and the exhibition of only two specimens, and 

 both from the same hand, should be produced to prove it. Mineralists might 

 then doubt whether what Mr. Borlase calls tin, was really that metal, or rather 

 an arsenical marcasite, or other mineral, which might appear like tin, or be 

 mistaken for it. He thought it very necessary to remove all doubts, by making 

 proper experiments to try if it was tin; it being so extraordinary a discovery. 

 The experiments he made, and which he hoped would prove satisfactory, to 

 convince every one that it is really tin, are as follow; 1. It was perfectly ductile 

 and malleable; and, bent between the teeth, gave the same crackling noise as 

 tin always does. 2. In an open fire it melted easily, calcined on the surface, 

 and smoked somewhat; forced in a stronger fire, with borax, it detonated with 

 small phosphorescent sparks, which is a property of pure tin. 3. It was only 

 corroded to a white calx in spirit of nitre, and oil of tartar per deliquium being 

 added to the solution, not any thing was precipitated. It was therefore pure tin. 



FJII. Abstract of a Letter from Edward fVortley Montagu * Esq. F. R. S. to 

 William Watson, M. D., F. R. S. containing an Account of his Journey from 

 Cairo, in Egypt, to the Written Mountains, in the Desart of Sinai. Dated 

 Pisa, Dec.1, 1765. p. 40. 



. Mr. M. set out from Cairo, by the road known by the name of Tauriche 



* Edw. Wortley Montagu, or Mountagu as he himself writes it, was a most singular and eccen- 

 tric character. He was the son of the famous Lady Mary \V. M. by her husband Edw. W. M. and 

 was bom at Warncliffe-lodge, in Yorkshire, about 1714; and he died in Italy in 1776", consequently 

 at 62 years of age. His father going ambassador to Constantinople in 17 l6, Lady Maiy accompa- 

 nied him, with her young son Edward ; where observing that the country people practisixl inocula- 



