3l5 Aciion of fome latel)- difcovered Metals and 'Earths 



a zeolite; for example, in its internal compofition, in having 

 been found in a whin rock adhering to prehnife, and in pro- 

 ducing a jelly with acids. Tremolites have a higher fpecitic 

 gravity than this ftone, are more infufible, and are confider- 

 ably different in their compofition *. Befides, fuch kinds of 

 tremoHte as I have examined cannot be decompofed by acids 

 even when boiling, and muti be heated with potalh or foda 

 before their component parts can be feparated ; but the fub- 

 ftance in quellion is completely decompofed by acids, like 

 the greater number of zeolites, in a very few minutes, and 

 without the afliftance of heat. For thefe reafons it appears 

 to me to be a zeolite. 



LI. Experiments refpcB'ing the ASllon offnme lately difcovered 

 Metals and Earths 07i the Colouring Matter of Cochineal, 

 By M. Hermstaedt f. 



J. O prepare the cochineal for thefe experiments, two ounces 

 of Mexican cochineal of the firft quality, being reduced to 

 fine powder, were boiled in a tin bafon with 74 ounces of 

 diftilled water. The liquor was then filtered and nieafured : 

 it had loft two ounces by evaporation. It was then divided 

 into portions of 2\ ounces for each experiment. 



A piece of kerfeymere dipped in this tin6lure when taken 

 out was of a lilac colour. 



Exp. I. A faturated folution of very pure cobalt in nitric 

 acid was dropped into a portion of the tinfture of cochineal. 

 The tinfture became very clear, alfumed a yellowiih red co- 

 lour, but remained diaphanous. After twelve hours there 

 was depofited a precipitate of a fulphur-red colour; which, 

 however, was in fuch fmall quantity that it was impoflible to 

 colle6l it. 



Exp. II. Part of the folution of cobalt in nitric acid was 

 diluted with water heated to ebullition in a glafs veffel, and 

 kept boiling for three minutes, with a piece of kerfeymere 

 24 inches (quare. The kerfeymere thus prepared being then 

 immerled in th^ warm timSture of cochineal, immediately 

 affumed a faturated bright red colour, leaving the tin6ture 



• Kirwan's Mineralogy, vol. i. p. 178. Traitc de Mineralogie par 

 Haiiy, tome iii. p. 151 and 2^7. 



t From Scherer's AUgfrneina Jonrnal dcr Chifnle, January 180s. 



colourlefs. 



