CHEMICAL SCIENCE. 277 



ties which constitute its fitness for culture, and which depend upon a 

 modification of chemical action." The amazing yield of Indian corn 

 in Mexico from 200 to 600 fold is something which, with all our 

 skill, we cannot accomplish, and is a fact in favor of the argument, 

 " that in no case do the organic substances contained in the ground 

 perform any direct part of the nutrition of plants." The annual 

 destruction of organic matter all over the earth is estimated at 145 bil- 

 lions of pounds, equal to 2 billions of cubic feet; and if all vegeta- 

 tion depends on organic matter for nutrition, to satisfy this consump- 

 tion " there must have been, five thousand years back, ten feet deep 

 of pure organic substance on its surface." Another illustration is 

 furnished by taking the number of cattle and other animals in France 

 in a given year (1844), and observing the amount of food they con- 

 sume. The process of nutrition would require 76,789,000,000 pounds 

 of organic matter six times more than the whole number contribute 

 of organic matter towards reproduction, and in 100 years " the whole 

 organic material of the country would be consumed." 



Again ; look at a farm. How much more is carried off from it than 

 is given back again : generally the amount of its yield is three times 

 greater than that of the organic matter it receives ; while of the 

 manure applied, the greater part is not taken up, but imperceptibly 

 decomposed. Carbon is the most important of the constituents of 

 plants : an acre of sugar plantation produces 7500 pounds of canes, of 

 which 1200 pounds are carbon, and yet sugar plantations are rarely 

 manured, and then only with the ashes of the burnt canes. With 

 bananas the result is still more striking: the yield is 98,000 pounds of 

 fruit in a year from a single acre, and of this 17,000 pounds more 

 than a fifth is carbon ; and the same acre will give the same return 

 year after year for twenty or thirty years ; and the ground at the end 

 of that time will be richer than at the commencement, from nothing 

 more than the decay of the large leaves of the plant. Here in Eu- 

 rope, too, the difference in weight and in carbon between the seed and 

 the produce has often been noted in wheat, 89 per cent. ; in red 

 clover, 158 per cent. ; and in peas, 361 per cent. These facts afford 

 evidence of a supply of carbon derived from other sources than those 

 commonly supposed to exist ; and while we know that seeds will ger- 

 minate and become vigorous plants in pure quartzose sand, or in cotton 

 wool, or on a board, we seem to have proof that the chief source of 

 supply is the atmosphere. This is an interesting point, which further 

 research will verify : Schleiden shews the process to be eminently sim- 

 ple. He says in his work, of which a translation has been published 

 bv the Horticultural Society: "According to Link, Schwartz, and 



t, * ^ O ' 



others, an acre of water meadow contains 4400 pounds of hay, which, 

 when dry, contains 45-8 per cent, of carbon. The hay then yields 

 2000 pounds of carbon, to which 1000 pounds may be added for the 

 portion of the year in which the grass is not cut, and the roots. To 

 produce these 3000 pounds of carbon, 10,980 pounds of carbon acid 

 is requisite, which may be raised to 12,000 pounds, to compensate for 

 the nightly expiration. Now, Schubler has shewn that an acre of so 



