224 ^^ PORCELAIJC. 



VIII. 



Extract from a Letter of M, Proust, to M. Vauqudin, 

 on Porcelain and on the Almcntarij Use of lAchcn 

 Isla.'idicun^, 



Madrid, Dec. 22, 1805. 

 Sir, 



Excellent pot- JL WAS visited by one of jour pupils, M. Siquicra, an 

 spirnia mari°"^ interesting and intelligent Portuguese young gentleman. 

 We are going, to-morrow, to see the manutacture of por- 

 celain under the direction of M. Sureda, who was 

 brought up to this art in the manufactory of Sevres, and 

 now makes a most beautiful porcelain, of a much harder 

 texture than yours. This is not effected by means of 

 Itaolin, but with the spuma maris, a siliceous magnesian 

 stone, found in the neighbourhood of Madrid j we shall 

 send you some patterns which will astonish you. He 

 covers his biscuit with feldspaths of Gallicia, which are 

 Tery beautiful. The stone above mentioned would be 

 excellent for the construction of chemical furnaces. 

 When taken from the quarry, it is soft and admits of 

 being cut like soap. Furnaces made of this stone arc 

 extremely light, and nev^ undergo fusion, however in- 

 tense the heat may be. Were such a fossil to be met 

 M\i\\ near Paris, we might do without the rue mazUm 

 rine, (qu?). Besides magnesia, silex, and some particles 

 of argil and lime, this stone contains a portion of potash, 

 which contributes, not a little, to the superior qualities of 

 the porcelain. 

 Lichen Island- '^^^ following fact is perhaps no less interesting than 

 icus; its value that above alluded to. Don Mariano la Gasca, pupil of 

 Cavanillez, a young botanist of great promise, has just 

 presented me with a specimen of Lichen (Islandicus) 

 which he has discovered in the mountains of Leon, whcra 

 it grows plentifully. 



I expected to find in it merely a weaker or stronger tinc- 

 torial matter ; but I find when properly boiled it is very 

 -good to eat, is very tender, and, I think ought to be con- 



* Annale» de Chimic, Vol LVIL p. Z96.— February i8o6. 



- a sidered 



