Among the advantages offered by this improvement are increased grinding capacity with a given amount of power, more even grinding and better yield, and lastly, but not less important, increased facility in obtaining a perfect running balance. It will be observed that the runner is supported upon a steel seat secured in the stone permanently--being substantially the same in this respect as when the ordinary balance-iron is used. The power being transmitted to the stone by the adjustable part of the iron and no weight upon any part of it, with the entire structure of the form to give the greatest attainable firmness and durability, combine to make it perfection as a driving iron, and it is accordingly in extensive use, although no especial effort has been made until late for their manufacture and sale. They are made in the best manner by skillful men and machinery adapted for the purpose, the parts well fitted and turned true inside where the grain enters and passes. They are made of the following sizes: 8½, 10 and 12 inches diameter. To order for attaching to stones with other irons already in, give diameter of the eye in stone at the face. Distance from the cock-head point to the lower side of the driver. Shape of cock-head as near as you can. Shape and exact size of spindle where your present driver goes on. In getting the shape as well as size of place where your present driver fits, it is a good plan to oil the inside surface of the hole in driver (in which the spindle fits) and fill it with plaster, then take out and send the cast by express. The shape of cock-head may be got by similar process. We will send necessary instructions, so that any one of medium skill can put them in at the mill. Give names, post office, county, and shipping point plainly, and how you wish to pay us. Money sent by Post Office Order is safe, and payment with the order always saves delay and trouble of making out bills, book-entries, &c. To those whose faith is not sufficient, will send the irons on trial or as circumstances best suggest at the time. The safe arrival of them is guaranteed. Every iron is warranted. [Illustration: Fig. 1.] [Illustration: Fig. 2.] These two cuts are intended to represent the self-tram irons for our under-runner mills. Fig. 1 shows the form of the outside, as it appears before being bedded in the centre, and iron back of the runner stone. Fig. 2 is a view of the inside, showing where the point of the spindle and driver rest. OIL BUSH. [Illustration]