66 A TOUfi EOUND MY GAKDEN. 



of it than they have taken; the action of the sun decom- 

 posing the carbonic acid gas. 



These two phenomena explain the danger there is in 

 keeping vegetables during' the night in a close chamber, for 

 then the vegetables absorb a part of the oxygen, and diminish 

 the quantity of respirable air. This quantity, necessary for 

 every man, is more considerable than is generally imagined. 

 A man consumes per hour at least six cubic metres of air. 

 Most of our pleasures taken in common, — as balls, soirees, 

 theatres, assemblies, — ^begin by considerably diminishing this 

 indispensable ration. It is difficult in a rout or soir§e, as they 

 are now-a-days given, for each person to have for his part 

 more than a metre and a half of respirable air. You would 

 not easily determine to enjoy any of these pleasures if you 

 were obliged to buy them at the price of the privation 

 of two-thirds of your food. The privation of air produces 

 effects less immediate; but it is probable that it engen- 

 ders great part of the diseases peculiar to the inhabitants of 

 cities. 



Besides that, vegetables shut up in a chamber absorb a 

 part of the oxygen, they expire an equal portion of carbonic 

 acid gas, which is a mortal poison when mixed in too strong 

 a proportion with the air we breathe, and of which it is 

 nevertheless one of the elements. This equally explains the 

 pleasure we experience in the day time under trees, a happi- 

 ness which is not to be attributed merely to the freshness and 

 shade. 



You see, my friend, that without its being necessary to 

 change our place, it is sufficient to look around us to see 

 new and surprising things pass, without ceasing, before our 

 eyes. Not one of the plants, not one of the insects, of 

 which I have spoken to you in this and the preceding 

 letters, blossoms, shows itself, shuts up, is transformed, or 

 dies, either before or after the epoch, the day, the hour as- 

 signed it. 



The dandelion always open its rays of gold before the daisy 

 displays its rays of silver; the (snothera never develops its 

 corolla before the water-lily has folded up its petals. The 

 blackbird whistles in the morning; the nightingale sings 



