Journal, have a direct bearing on this subject.  The researches of Prof.  Emmons of Albany, in his elaborate and valuable work on “Agriculture,” as a part of the Natural History of New York, show that 10,000 parts of soil yield only from one to three parts of soluble silica.  The analyses of Dr Jackson, as published in his Geological Survey of New Hampshire, give similar results.  Earth taken from an old and badly exhausted field in Georgia, gave the writer only one part of soluble flint in 100,000.

What elements of crops rain water, at summer heat, will dissolve out of ten or twenty pounds of soil, in the course of three months, is a point in agricultural science which should be made the subject of numerous and rigid experiments.  In this way, the capabilities of different soils and their adaptation to different crops may be tested, in connection with practical experiments in field culture, on the same kind of earth.

Few wheat-growers are aware how much dissolved flint an acre of good wheat demands to prevent its having coarse, soft, and spongy stems, which are anything but a healthy organization of the plant.  In the Journal of the Royal Agricultural Society of England, vol. 7, there is an extended “Report on the Analysis of the Ashes of Plants, by Thomas Way, Professor of Chemistry at the Royal Agricultural College, Cirencester,” which gives the result of sixty-two analyses of the ash of wheat, from as many samples of that grain, mostly grown on different soils and under different circumstances.

In this report are given the quantity of wheat per acre, the weight of straw cut close to the ground to the acre, and also that of the chaff.  These researches show, that from ninety-three to one hundred and fifty pounds of soluble flint are required to form an acre of wheat; and I will add from my own investigations, that three-fourths of this silica is demanded by nature during the last sixty days preceding the maturing of the crop.  This is the period in which the stem acquires its solidity and strength, and most of its incombustible earthy matter.  The quantity of this varies from three to fifteen per cent. of the weight of the straw.  Prof.  Johnston and Sir Humphry Davy give instances in which more than fifteen per cent. of ash was found; and Prof.  Way gives cases where less than three per cent. were obtained.  The mean of forty samples was four and a half per cent.  Dr. Sprengel gives three and a half as the mean of his analyses.  M. Boussingault found an average of seven per cent.  As flint is truly the bone of all the grass family, imparting to them strength, as in cane, timothy, corn, oats, rye, rice, millet, and the proportion of this mineral varies as much in wheat-straw, as bone does in very lean and very fat hogs or cattle.

A young growing animal, whether a child or a colt, that is kept on food which lacks bone-earth, (phosphate of lime,) will have soft cartilaginous