A PHILOSOPHICAL TRANSACTIONS. [aNNO 1755. 



a bright copper-colour ; and needles and nails kept immersed in it a month in a 

 phial are covered with a rust, partly yellow and shining, which seems to be the 

 copper, and partly a ferrugineous matter, as appeared by the magnet : and that 

 it was partly cupreous appeared by the bright blue tincture extracted by spirit of 

 hartshorn from such parts of the rust as did not readily fly to the magnet ; and, 

 if one might rely on the Philadelphia experiment above-mentioned, the proportion 

 of copper should be very large. 



It is however certain, that as in other copper-springs, so in this, here is a 

 very considerable proportion of the vitriol of iron combined with it, and by all 

 experiments a much greater than of the vitriol of copper ; and accordingly, galls 

 added to this water turned it first blue (the characteristic of martial vitriol) and 

 then of a dilute ink-colour ; and the corks in the bottles were blackened. But 

 the genuine quality, as well as a large proportion, of the impregnating salt, will 

 further appear by the following analysis of this water, viz. a pint of it, exhaled 

 by a slow fire, left 400 grains of solid contents, which were partly green and 

 partly ochre-coloured, with an intermixture of bluish, and of a rough, sweetish 

 taste, like that of sal martis, and appeared to be chiefly saline, not leaving above 

 4 grains of indissoluble matter on dissolving 196 grains of it, and filtring. 



Thus it appears, that the proportion of vitriolic parts in this water is very 

 large, viz. above 6 drams to a pint or 3200 grains to a gallon ; and consequently 

 it is a stronger solution of vitriol than sea-water is of marine salt ; and is consi- 

 derably the strongest of all the vitriolic waters, that have yet occurred to my 

 observation ; for our Cronebaun water, in the county of Wicklow, gives but 256 

 grains from a gallon ; Haigh in Lancashire, (the strongest in Britain, that I 

 know of) 1920 grains; Shadwell 1320; Kilbrew, in the county of Meath, 

 J 530 from the same quantity ; so that besides the copper to be obtained by im- 

 mersing bars of iron, as in our county of Wicklow water, this water offers to its 

 proprietors another peculiar advantage, viz. an opportunity of erecting a cop- 

 peras-work or manufacture of vitriol, like the Hungarian vitriol; especially the 

 vast supply of water and plenty of fuel in the place considered. 



C. Extract of a Letter from the ^bbe Mazeas, F.R.S. concerning an Ancient 

 Method of Painting, Revived by Count Caylus.* Translated from the French 

 by James Parsons, M. £)., F. R. S. p. 652. 

 The Count de Caylus, a member of the Academy of Inscriptions, had under- 



* A celebrated French antiquary, author of a splendid work entitled Antiquitcs Egyptiennes, Etrus- 

 ques, Grecques, Romaines et Gauloises, in 7 vols. 4to. The last vol. contains an eloge of the author 

 by Mons. le Beau. He was a great encourager of artists, and wrote the Lives of several Painters and 

 Engravers to the French Academy. In addition to the works just mentioned, there are many learned 

 dissertations by this author in the Memoirs of the Academy of Inscriptions. Count Caylus died in 

 1765, in the 73d year pf his age. 



