1825.] Mr. Phillips's Rep/i/ to Mr. Whipple. 53 



part of the tube was filled with a yellow vapour, a good deal 

 like chlorine, but of a deeper colour, and an unpleasant odour 

 was exhaled, very similar to that of cabbage water. After the 

 whole of the volatile matter had been sublimed, a fixed dark 

 coloured residuum remamed at the bottom of the tube. This 

 was transferred to another tube, open at both ends, and again 

 heated ; some more of the red sublimate was thus obtained, and 

 the residuum assumed a grey colour. It amounted to about 

 53 per cent, of the weight of the substance operated on, and on 

 examination was found to consist of earthy matter, principally 

 silica and lime ; consequently the assay contains about 47 per 

 cent, of volatile matters, by far the greatest portion of which 

 consists of the red sublimate. The red sublimate had evidently 

 been fused and spread over the inner surface of the tube. 



When detached from the tube, a morsel of it imparted the same 

 beautiful blue colour to flame that has been already mentioned, 

 but more intense. 



Another fragment, heated in a tube open at both ends, sub- 

 limed without giving ofi'any sulphur, exhahng at the same lime 

 a strong odour similar to that of horse-radish. It fused very 

 readily on being gently heated in a close tube over the lamp, 

 and remained tor some time in a soft pasty state. 



These experiments are quite sufficient to establish the identity 

 of our red subUmate with selenium, and in external characters 

 also it perfectly answers the description of that substance. It 

 has a metallic lustre, and a deep brown colour when seen by 

 reflected light. Its fracture is conchoidal, and has a vitreous 

 lustre. It IS easily scratched by the knife; is brittle, and its 

 powder has a deep red colour ; but it adheres together readily 

 when rubbed in the mortar, and then assumes a grey colour, 

 and a smooth and somewhat metaUic surface. In very thin 

 lamina; it is transparent, and when viewed by transmitted' light, 

 has a beautiful cinnabar red colour. 



Article X. 



OhservalioiiH upon Mr. Whipple's Amwer. By ll. Phillips, 



FRS. L. and E. Scc 



In the stvenlh volume of the Aiuin Is oj' Fhil<)sophij,\-).-\'}0,'^ .'^. 

 I offered some remarks upon the Phaiunicopceia Londineusis, 

 lately published by the College of P:iysicians ; and in the last 

 number of the Annals, I am requested by a correspondent who 

 subscribes himself " G. VVhij)ple," to give him an explanation of 

 them. The manner of Mr. \Vhi])ple's communication is such as 

 would have prevented its appearance, if any one but myself had 

 been the object of it, I sliall, however, show, that he niav at 



