One large mining company in Kentucky raises its own timbers by planting trees in straight, close rows on its coal land, thus making the land produce its own mine timbers to conserve the coal below. This company claims to have lost but one life in ten years, and to save seventy-five per cent. of its coal. This is a striking illustration of what better mining methods will do for both the miner and the mine owner and of how forestry may be an aid to the conservation of coal and also of human life in the mines. We have already shown how half of the coal is wasted, but there still remains another source of waste at the mines. This is a large but unknown quantity. Coal usually exists in beds or layers with shale or rock between, much as a "layer-cake" is made, the layers of cake being represented by the coal and the icing between by these "rock-partings," as they are called. In rich fields, there are from three to ten of these rich layers or beds of coal, one above another. It often happens that the thickest and best layer is the lowest, and when this is the case, it is usually mined first, regardless of the fact that some, and possibly all, of the higher beds are dislocated and broken or filled with deadly gases. Nearly all this loss could be avoided by simply mining the upper stratum first. So much for waste at the mines. This is serious enough if it were all, but it is not all, it is only the beginning. Let us see now what becomes of the coal that is marketed. The railroads are the largest single users of coal, and here we are confronted with the surprising statement that our locomotives consume three tons of coal in doing the same work that is performed by English locomotives with one ton. This difference is said to be due to different construction of the engines themselves, and to more careful stoking, or firing. Our locomotives use 100,000,000 tons per year, and by even the best methods known a large proportion of the heat units is wasted. Great effort should be made to improve the locomotives so that they will consume less coal; but as long as the railroad companies own the coal mines, as they do in many instances, they can obtain coal so cheaply that the cost of the improved form of engine is greater than the amount saved. Another great use lies in the manufacture of coke, which is used in the making of steel, and here, too, we see where great wastes have existed. The old form of coke-oven was called the bee-hive on account of its shape. These old style ovens consume all the coal with the exception of the fixed carbon which is left behind as coke. At the prices which prevailed in 1907, the value of the by-products wasted in bee-hive coke-ovens was a little over $55,000,000--surely a loss worth considering. A different form of coke-ovens is much used abroad and is coming into use in this country. This is the retort or by-product oven, sometimes called the recovery oven.