147 
402. Mr Delaval, also, digested red, purple, and 
blue flowers in acidulated water, and thus obtained 
red liquors, which, by very small portions of alkali, 
were changed to purple, blue and green. The addi- 
tion of the alkali must, he says, be very gradual ; 
for if too much be added at once, the intermediate 
colours between the red and the green will not be 
produced. He likewise digested red, purple, and 
blue flowers in alcohol, to which they yielded their 
colourable matter, and became white. From most 
of them, however, the alcohol acquired either no 
colour, or only a faint tinge ; but when it was acidu- 
lated, it became ^red, and, by the addition of an al- 
kali, assumed purple, blue and green colours *. 
403. The foregoing facts clearly shew, that all 
flowers contain a colourable matter, which, whether 
it be extracted by water or by alcohol, experiences 
changes from acid and alkaline matter similar to 
those which the juices of the leaves exhibit, but mo- 
dified, in some instances, by the peculiar qualities of 
the flowers employed. Hence we may venture to 
ascribe their colours to the diversified operation of 
the same general agents, which produce the coloura- 
tion of leaves ; and the infinite variety of tints which 
they afford, must, therefore, be referred to the vari- 
ous combinations of acid and alkali with their colour- 
able matter, modified by the peculiar qualities of 
that matter, and probably by the structure of the 
Munch. Mem. vol. ii. p. l6o. 
K2 
