4 THE GRAPE. 



fermented liquid from equalling the other in flavour 

 and aroma. Or is it, perhaps, that the heat of the 

 sun penetrates more thoroughly the purple grape, 

 while its dark skin partially preserves it from the 

 action of light ? 



Is then the same chemical action possible to the juice 

 of the purple grape (enclosed, as it were, in a small 

 bladder) as that which is produced in the juice of the 

 white grape by the difference between these two pow- 

 erful influences, heat and light p "We know that in our 

 regions, the white grapes are much sweeter than the 

 purple, and ascribe this peculiarity to the difference 

 of the plants, but forget that in the easier passage of 

 the light through the colourless skin of the white 

 grape we possess a sufficient explanation of a more 

 powerful chemical action, the result of which may be 

 a larger formation of sugar. And if we generally 

 find the purple grapes inferior in flavour and smell, 

 we must ascribe this circumstance to heat, which in 

 this case penetrates more easily the skin of the 

 grape, and which in all living things is a powerful 

 means of exciting chemical action. The principal 

 component of the weight of the juice of ripe grapes 

 is (in proportion to the weight) water, in which are 

 various substances, either held in solution, or very 

 minutely divided. As the juice is obtained by pres- 

 sure, it is thick, and exposure to the heat of the sun 

 changes it very quickly into a fermented liquor. As 

 principal components we find in the juice sugar 



