302 
Nutrition of Vegetables . 
gave no signs of vegetation ; whence he inferred, that the absorp- 
tion of carbonic acid by the lime was the cause of their death, and 
that the elaboration of this acid was necessary to vegetation in the 
sun. But I cannot be of his opinion. I have examined the ex- 
periment carefully, and satisfied myself, that the death of the 
plants was not owing to the privation of carbonic acid alone,, but 
to the lime itself in vapour. 
The following experiments convinced me of the volatility of 
lime. 
1. Paper tinged by repeated immersion in infusion of litmus, 
then reddened, and afterward washed in water to remove its ex- 
cess of acid, was suspended in a stopped phial, into which I had 
put with great caution some lime, that was slaked, and suitably- 
moistened with water. It was not long oefore the red colour of 
the paper was changed to blue. This effect was not unknown to 
Fourcroy. 
2. Into a retort I put with all possible precaution a certain 
quantity of lime and water, and by distillation 1 obtained a liquor 
Impregnated with an intolerable smell of lime. This liquor left 
a disagreeable impression on the palate, and had manifestly alka- 
line properties. 
Alcohol by its volatility carries up in vapour a much larger 
quantity of lime, as appears from an experiment of Proust. In 
order to obtain spirit free from acetic acid, he distilled 25lbs. of 
red wine with a handful of quicklime. The product was so much 
impregnated with the taste and smell of the lime, that he was 
surprised. When redistilled it had the same taste, precipitated 
metallic solutions and oxalic acid, and restored the blue of litmus. 
Lime is not the only fixed alkali, that shows a disposition td 
rise at a pretty low temperature. 
A solution of potash, subjected to distillation, afforded me a 
water with a strong lixivial smell. This water redistilled retain- 
ed the same smell, and gave with nitrate of lead a white flocculent 
precipitate, which was completely soluble in distilled vinegar. 
But there are other substances besides alkalies, the volatility 
of which is so little apparent in the temperature of the atmos- 
phere, that it is discoverable only from its effects on organized 
beings. 
Some Dutch chemists set plants in water, by the side of which 
they placed a small bottle of mercury, and covered the whole with 
a jar standing in water. On the third day the plants were co- 
