“Yes, and the Illinois farmers have it shipped in bulk, so there is no expense for barrels or bags.  Of course the supplies of both coal and limestone are very abundant, and with a well-equipped plant the actual cost of grinding does not exceed twenty-five cents a ton.  The original cost of the material ground and on board cars at the works varies from about sixty cents to one dollar a ton, and this leaves a very fair margin of profit.

“The men who furnish the ground limestone realize that very large quantities of it are needed if the soils of Illinois are to be kept fertile, and they also realize that the ultimate prosperity of the country depends upon agricultural prosperity.  Their far-sightedness and patriotism combine to lead them to try to sell carloads of limestone instead of tons of burned lime.  As a matter of fact five or ten dollars profit on a car of limestone, the use of which in large quantities is thus made possible in systems of positive soil improvement, is very much better for all concerned than a profit of half that much on a single ton of burned lime which is used as a soil stimulant in systems of soil exhaustion.”

“It is certainly true,” said Mr. Thornton, “that all other great industries depend upon agriculture, directly or indirectly.  I have thought of it many times.  It seems to me that fishing is about the only exception of importance.”

Mr. Thornton requested that Percy remain for lunch in order that they might return to the field to let him see the soil acidity tests made.

CHAPTER XIII

WHY PERCY WENT TO COLLEGE

“I am interested to know where you learned these things about acid soils and lime and limestone,” said Mr. Thornton.

“Mostly in the agricultural college,” replied Percy, “but much of the information really comes from the investigations that are conducted by the experiment stations.  For example, the best information the world affords concerning the comparative value of burned lime and ground limestone is furnished by the Pennsylvania Agricultural Experiment Station.  Those experiments have been carried on continuously since 1882, and the results of twenty years’ careful investigations have recently been published.  A four-year rotation of crops was practiced, including corn, oats, wheat, and hay, the hay being clover and timothy mixed.  With every crop the limestone has given better results than the burned lime.  In fact the burned lime seems to have produced injurious results of late years, and the analysis of the soil shows that there has been large loss of humus and nitrogen where the burned lime has been used, the actual loss being equivalent to the destruction of more than two tons of farm manure per acre per annum.”

“Well, we surely need this information,” said Mr. Thornton.  “I have always supposed that the teachers in the agricultural college knew little or nothing of practical farming.”