28 CHEMICAL MANUKES 



elusions above all dispute by showing the experiments in burnt sand, 

 which contains nothing not well known and defined. 



In burnt sand, free from all additions, but moistened with distilled 

 water, wheat acquires but a rudimentary development the straw 

 hardly attains the dimensions of a knitting-needle. In this con- 

 dition, however, vegetation follows its usual course ; the plant blooms, 

 bears grain, but in each head there are but one or two dwarfed, 

 badly-formed grains. Thus, without soil, the wheat finds in the 

 water it receives and the carbonic acid of air, aided by the substance 

 of its grain, resources sufficient sorrowfully, it is true, but at last 

 to run through the entire cycle of its evolution. 



From 22 grains of seed, weighing nearly 18 grains, we obtain 108 

 grains of harvest. Add the ten minerals to the sand, excluding the 

 azotic matter, and the result is but little more. 



Under these new conditions the wheat is a little more developed 

 than in the preceding case, but the harvest is still more feeble ; it 

 reaches 144 grains. Suppress the minerals and add only azotic 

 matter to the sand ; the growth will still be mean and stunted, but 

 the harvest will slightly increase, as it reaches 162 grains. Let us 

 follow the changes. In pure burnt sand, 108 grains ; with minerals 

 without azotic matter, 144 grains; with azotic matter alone, 162 

 grains. 



In this last case a new symptom is shown. As long as we operate 

 only with minerals the plants are diseased, the leaves show a yellowish- 

 green color. As soon as we add azotic matter to the sand the leaves 

 change their color, becoming a dark green. It seems as if vegetation 

 would take its usual course, but the appearances are deceitful ; the 

 harvest is still feeble. 



Until now, you see, we have not gone beyond the most rudimentary 

 returns. Let us attempt a third experiment, which will, in a measure, 

 be a synthesis of the three preceding. Unite azotic matter and the 

 minerals in the burnt sand. This time, gentlemen, you will be 

 tempted to believe in the intervention of a magician, the phenomena 

 so far surpasses those preceding it. Just now the growth was lan- 

 guishing, doubtful, diseased ; now the plants shoot up as soon as they 

 break the ground ; the leaves are a beautiful green ; the straight, 

 firm stalk ends in a head filled with good grain ; the harvest reaches 

 from 396 to 450 grains. 



You see, gentlemen, relying upon experience, which is our guide 

 by choice, we have succeeded in artificially producing vegetation to 

 the exclusion of manures and all unknown substances. 



You will acknowledge that this is an important and fundamental 

 point. No more mystery, no undetermined power; some chemical 

 products of a known purity, distilled water perfectly pure in itself, 

 one seed as a starting-point, and the result, a harvest comparable in 

 all points to the best obtained in good earth. 



We are, therefore, justified in saying that the problem of vegeta- 

 tion here receives its solution, for we have not only defined the con- 

 ditions necessary to the production of vegetation, but the degree of 

 importance of each of the concurring agents. 



