Porcelain and Porcelain Clays. 57 



agatized, and veins of chalcedony occasionally pervade the 

 fissures : they are not impressible by steel, and give fire with 

 it. According to the infijrmation of Mr. Perit, they are scat- 

 tered over the surface of the Island of Antigua, with a pro- 

 fusion hardly, less than that which Horneman observed of the 

 same mineral during his travels over the eastern part of the 

 great African desert. 



It is much to be wished that our numerous intelligent navi- 

 gators and travelling merchants would, in imitation of this and 

 of a similar example, mentioned below, bestow some share of 

 their attention on the natural productions of the countries 

 which they visit. In this way they might, on their return, 

 render very essential services to the science of their own 

 country. 



Art. VII. Porcelain and Porcelain Clays. 



jL HROUGH the kind offices of a friend, we have been fur- 

 nished, from one of the great porcelain manufactories in the 

 vicinity of Paris, with a series of specimens, to illustrate the 

 elegant art of fabricating porcelain. The specimens begin 

 with the raw materials, and exhibit them in all their principal 

 stages of advancement up to the perfect vessel, including the 

 materials for the glazing, and the colours for the painting, and 

 the application of both. At the request of the manufacturer, 

 through whose liberahty we were indulged with this gratifica- 

 tion, we transmitted to Paris various specimens of American 

 porcelain clays. This gentleman has caused them to be sub- 

 jected to trials in the porcelain furnaces, and he finds that some 

 of them are equal to the French porcelain clays, and some 

 superior. As our specimens were all labelled with the names 

 of the places, in this country, from which they were obtained, 

 we hope soon to learn where to look for porcelain clays, equal 

 or superior to those celebrated ones from which the superb 

 French porcelain is manufactured. 



