-j;68 Native Pi-ujfian Blue. — Native Copper. 



■ The remainder of Mr. Little's paper, confifts of numerous obfervations and remarks, with 

 feme experiments ; a confiderable number of the former of which arc familiar to fuch as 

 have attended to this branch of natural philofophy : but the whole, though evidently fhort of 

 what the author muft have originally intended, will be read with inter^ft and fatisfadlion, by 

 thofe who may confult the memoir itfelf. 



-a 

 X, 



OVfervaiions on Chem'ijiry and Natural Hijlory. By PjlOF£SSOJl VaNDELLI*. 

 I . Fojil Prujfian Blue from Mitias Geraes in the Brazils. 



An digging a mine at S. loao del Rey, to the depth of more than forty palms (about 27 (cet 

 Englilh), large brittle bones, and fome teeth of a cetaceous animal were found in the clay, 

 which occupied a fpace of more than fifty palms fquare (about 35 feet Englifh). Thefe bones, 

 and the clay with which they were intermixed, were white when firft extraded, but foon 

 became blue when expofed to the air f. 



Thefe.bones and clay, in the blue (late, being expofed to the aftion of a moderate fire, be- 

 came green, emitted a weak flame, and afterwards loft their colour. The reddifh earth which 

 remained was, for the moftpart, attraftedby the magnet. 



The Pruffian blue was foluble inthe marine acid, and in this ftate loft its colour. By addi- 

 tion of a fixed alkali, the precipitate was afforded of a green colour, which afterwards became 

 blue, of more intenfity then at firft. 



. The mixture of bones and clay, being fufed with a proper flux for iron, afforded three 

 parts of their weight of iron, which was intirely attraded by the magnet. 



Refpeding the fofTil Pruffian blue, as the reader may confult the works of Wallerius, Berg- 

 man and Kirwan, I fhaH not enter into any further detail. 



.2. Native .Cupper of Brazil. This mafs of copper was found in a valley two leagues 

 from Cachoeira, and fourteen from Bahia. It weighs nearly 2616 arratels (or nearly pounds 

 Englifh), and its figure is rhomboidal, the upper furface being irregular, on account of fomc 

 cavities and protuberances. Its greateft height is three feet two inches, its width, at the bafe, 

 two feet and a half, and its greateft thicknefs ten inches, Paris meafure %. 



The external colour of the mafs is deep reddifh, with fpots and particles of a greenifh blue, 

 produced by the decompofition of the copper. On the lower furface appear fome yellow 

 fpots of ochre of iron. 



At various parts of the furface, particularly the lower furface, feveral pieces, large and 

 fmall, are obferved, which, at firft, feem to hzferrum micaceum ; but when examined by fire 

 they prove to be indurated oxide of copper. For an ounce of this fubftance afforded 

 thirteen parts out of fixteen pure copper. 



* From the Tranfaftions of the Royal Academy of Sciences at LiHon, I. 259. 

 if For an explanation of this phenomenon, fee Prouft in this Journal, I. 455. 

 J The foot-royal ofParis is to that of London a»j,Qooo to 0,9383. — l^L 



Tlug 



