Apparatus Jor the Comhujl'ion ofPhofphorus. 83 



the latter loft all its colour, while that of the former was not 

 fenfibly weakened. 



*' The kind of lake formed by the union of vegetable co- 

 louring matter with the oxyd of tungften may be confidered, 

 therefore, as having been fubjedted to the ftrongeft teft by 

 the principles moft deftruftive to colours, and which Ber- 

 thollet confiders as the neareft, in point of ftrength, to the 

 continued aftion of the air and light. 



" I {hall pafs over a great number of other experiments 

 lefs direft, or at leaft lefs concluiive, refpe6\ing other vegeta- 

 ble colouring matters, and obferve only that the oxyd of 

 lead, which feems to have fo little aftion on the red juice of 

 ftoned fruits, attacks turnfol very ftrongly ; that an infufioa 

 of turnfol, rendered red by the acetous acid, pafles to a wine 

 colour when treated with iron, and is then in the ftate of 

 violet juices which become green by alkalies; that the acid 

 juice of yellow fruits, melons for example, gives to the oxyd 

 of tungften only a faint (hade of blue, which turns grey by 

 repeated waftiing ; and that, on the other hand, this oxyd, 

 digefted in infufions of curcuma (turmeric) and turnfol, be- 

 comes charged with their colours, and gives them a fixity 

 of which one would not have fuppofed them fufceptible." 



XIV. Defcription of an Apparatus in the Teyhrian Mufeum 

 for the Combujllon of Phnfphoms i?i Oxygen Gas; ivith> 

 Obfervations on the Shining of Fhofphorus in Azot. By 

 D. VAN Marum of Haarhm*. 



XI AVING made feveral fruitlefs attempts to render a bal- 

 iponforthe combuftion of phofphorus perfeilly air-tight, ac- 

 cording to the method defcribed by Lsvoificr in his Elements 

 of Cheniiftry, I conftruiled another like that which I employ- 



• From D(faipti<jn de quel^ucs opi>artils CUmi^uci, SiC. by Dr. van 

 Marum. 



62 ed 



