Artificial manures; their chemical selection and scientific application to agriculture . ety grains isobtained (Fig. 1). Add to the calcinedsand the ten inorganic elements, exclu-ding nitrogenous matter, and the resultis scarcely, if any, better. Under thesenew conditions the corn is rather moredeveloped than in the former case, butthe crop is still very feeble, amountingonly to about 123 grains (Fig. 2). Ke-versing this second experiment, we leaveout all the mineral matter and add a nitrogenous matter onlyto the sand (Fig. 3). The vegetation still remains very poorand stinted ; the yield, how
Artificial manures; their chemical selection and scientific application to agriculture . ety grains isobtained (Fig. 1). Add to the calcinedsand the ten inorganic elements, exclu-ding nitrogenous matter, and the resultis scarcely, if any, better. Under thesenew conditions the corn is rather moredeveloped than in the former case, butthe crop is still very feeble, amountingonly to about 123 grains (Fig. 2). Ke-versing this second experiment, we leaveout all the mineral matter and add a nitrogenous matter onlyto the sand (Fig. 3). The vegetation still remains very poorand stinted ; the yield, however, is somewhat larger, amount-ing to about 138 grains. The gradually increasing yieldshould be carefully noted. In pure calcined sand theyield was 92 grains; with the mineral matter, but withoutnitrogenous matter, 123 grains ; with nitrogenous matter, 138grains. In the last case a fresh phenomenon is long as we use mineral matter alone, the plants areetiolated, and the leaves are of a yellowish-green colour; butas soon as a nitrogenous matter is added to the sand, the. Fig. 1. LECT, 111. NORMAL MANUEE 29 leaves change their hue and become dark green, and it seemsas if the vegetation was about to assume its ordinary vigour;it is, hov^rever, only a deceitful appearance, for the cropremains as poor as ever. Up to the present time we have not exceeded the mostrudimentary returns; we will now try a fourth experiment,which is, in some sort, the synthesis of the three precedingones. We will add to the calcined sand both the mineral andnitrogenous matter. The result is almost magical, so greatly
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