per cent.  August 16, to 24.69 October 18.  When the plant is growing fastest, its roots yield an ash which contains less than one per cent. of lime; but after this development is nearly completed, the roots retain, or perhaps regain from the plant above, over 41/2 per cent. of this mineral.  Soda figures as high as from 20 to 31 per cent. in the ash obtained from corn roots.  Ripe seeds gave the following results on the analysis of their ash:—­

Silica 0.850
Phosphoric acid 49.210
Lime 0.075
Magnesia 17.600
Potash 23.175
Soda 3.605
Sodium 0.160
Chlorine 0.295
Sulphuric acid 0.515
Organic acids 5.700

                                        ------

                    99.175

The above table shows a smaller quantity of lime than is usually found in the ash of this grain.  It is, however, never so abundant as magnesia; and Professor Emmons has shown that the best corn lands in the State of New York contain a considerable quantity of magnesia.  All experience, as well as all chemical researches, go to prove that potash and phosphoric acid are important elements in the organisation of maize.  Corn yields more pounds of straw and grain on poor land than either wheat, rye, barley, or oats; and it does infinitely better on rich than on sterile soils.  To make the earth fertile, it is better economy to plant thick than to have the rows five feet apart each way, as is customary in some of the Southern States, and only one stalk in a hill.  This gives but one plant to twenty-five square feet of ground.  Instead of this, three square feet are sufficient for a single plant; and from that up to six, for the largest varieties of this crop.

Mr. Humboldt states the production of maize in the Antilles as 300 for one; and Mr. H. Colman has seen in several cases in the New England States of America, a return of 400 for one; that is to say, the hills being three feet apart each way, a peck of Indian corn would be sufficient seed for an acre.  If 100 bushels of grain is in such case produced by an acre—­and this sometimes happens—­this is clearly a return of 400 for one.

Of the whole family of cereals, Zea Mays is unquestionably the most valuable for cultivation in the United States.  When the time shall come that population presses closely on the highest capabilities of American soil, this plant, which is a native of the New World, will be found greatly to excel all others in the quantity of bread, meat, milk, and butter which it will yield from an acre of land.  With proper culture, it has no equal for the production of hay, in all cases where it is desirable to grow a large crop on a small surface.