The cylinders are cast separately and are furnished either with iron or copper water jackets, the copper jackets being deposited over the cylinder barrels by an electrolytic process in much the same way as that of the celebrated French Antoinette. Bolts passing through flanges on the bottom of the cylinder fasten them to the base. A special aluminum alloy is used for the base which is cast in a single piece with webs to receive the bearings. A unit crank-case insures perfect alignment, prevents a greater part of the oil leakage, and forms a much stronger construction than the usual split pattern. A chamber is provided for the cam shaft at the apex of the case through which issue the push-rods. Shafts and piston pins are hollow. All push rods are adjustable for wear and have steel balls running on the cams which eliminate the possibility of mis-timing through wear. Lubrication is by a bronze pump geared from the crank-shaft and is connected to an oil tank located in the base from which the oil is forced through the crank-shaft up through the hollow connecting rods to the piston pins, thence to the cylinder walls, the surplus returning to the tank in which the strainer is located. The circulating pump is driven from the cam shaft as shown in the cut and supplies the cylinders and radiator with water through the copper water manifolds which are designed to give an equal supply to each cylinder. Exhaust manifolds are of seamless steel tubing. The cylinders are 4⅛ bore × 4⅜ stroke, and develop 60 to 70 horse-power at 1,100 revolutions per minute, which speed has been attained with an 8-foot 6-inch propeller having a pitch of 5 feet. Without radiator or propeller, the iron jacketed motor weighs 312 pounds, and copper jacketed weighs 290 pounds, the latter making a difference of 22 pounds in the weight. A high tension Bosch magneto is used which is mounted on a pad cast on the top of the crank-case and is driven from a gear meshing with the cam shaft gear. Connection is made from the magneto to plugs placed over the inlet valves in the valve caps. A 100 horse-power aero engine of the “V” type is shown by Figs. 23–24–25, which is built by the All British Engine Company for the aeronautical branch of the English War Department. It has eight cylinders of 5 inch bore, by 4¼ inch stroke, and develops its rated horse-power at 1,200 revolutions per minute. _Data from “Aero,” London._ [Illustration: Fig. 23. Longitudinal Section Through A. B. C. 100 Horse-Power “V” Motor. ]