376 



NATIVE CONCRETE BORACIC ACIB; 



Boracld acid 

 found but in 

 few places. 



Volcanic pro- 

 duct from 

 Lipari. 



Native boracic 

 acid 



mixed with a 

 tenth of sul- 

 phur. 



Anotlier speci- 

 men. 



VIII. 



Notice respecting Native Concrete Boracic Acid: Bj/ 

 Smithson Tennant, Esq. F. R. S. Sfc. Communicated 

 hy L. Horner, Esq. Sec. of the Geological Society *. 



-iL HE boracic acid is not found, like the greater number 

 of substances, in almost every country ; but, as far as our 

 present knowledge extends, appears confined to a few par- 

 ticular places. On this account, as well as the great utility 

 of borax in various arts, the discovery of its existence ia 

 any new situation may deserve to be recorded. 



Some months ago Mr. Horner was so obliging as io show 

 me a collection of volcanic productions from the Lipari 

 Islands, presented to the Geological Society by Dr. Saunders. 

 They consisted chiefly of sulphur, and of saline sublima- 

 tions on the lava; but among these more common sub- 

 stances there were several pieces of a scaly shining appear- 

 ance, resembling boracic acid. The largest of these had 

 been cut of a rectangular shape, and was about seven or 

 eight inches in length, and five or six in breadth, as if it 

 had been taken from a considerable mass. On one side of 

 most of the pieces was a crust of sulphur, and the scaly 

 part itself was yellower than pure boracic acid. To as- 

 certain if the scaly part was coloured by sulphur, I exposed 

 it to heat in a glass tube, and, after the usual quantity of 

 water had come over, there sublimed from it about a tenth 

 of its weight of sulphur, and the remainder was pure bo- 

 racic acid. 



Mr. Horner afterward informed me, that i}\Q late Dr. 

 Menish of Chelmsford had presented to the Geological So- 

 ciety a specimen, which he had received, with some other 

 volcanic productions, from Sicily, but which had been col- 

 lected in the Lipari Islands ; the box containing them 

 being marked " Produzioni Volcaniche raccolte nelle Isole 

 Eolie da Gius. Lazzari. Lipari." He found it to consist of 

 boracic acid; and it perfectly resembled that I havt just 



* Trans, of the Geol. See. vol. i, p. 389. 



described 



