1 86 Mr. Delaval on the Cauje of the 



I expofcd feveral forts of red, and purple flowers 

 to the phlogiflion, difengaged from hepar ful- 

 phuris decompofed by an acid, and to other phlo- 

 giftic vapours, all of which whitened the flowers. 

 I reftored the red colour of each of thefc, by ap- 

 plying to them indifcriminately either vegetable, 

 or mineral, acids. 



It appears, from thefe experiments, that the 

 colouring matter of the flowers is not difcharged 

 or removed, but only diflTol ved, by the phlogifton ; 

 and thereby divided into particles too minute to 

 exhibit any colour. In this ftate, together with 

 the vegetable juice in which they are difFufed, 

 they form a colourlefs tranfparent covering, 

 through which the white matter of the flowers is 

 Utn untinged. 



The Colouring Particles of plants confid prin- 

 cipally of inflammable matter i and their folubility 

 in phlogifton, and union with it, are analagous to 

 the mutual adlion, which other inflammable bo- 

 dies exert on each other. Thus, sether difiblves 

 all eflential, and exprefled oils, animal empyreu^ 

 matic oils, and refins. Sulphur, camphire, and 

 almoft all fubftances abounding in phlogifton, are 

 foluble in oils, ardent fpirits, or other inflammg,' 

 ble menftrua. 



The manner, in which the red colour of the 

 flowers is reftored, appears to me to be explicable 

 from known chemical laws. When acids are ap,- 

 plied to the whitened flowers, by their ftrong 



affinitj' 



