The accompanying sketch shows a playground trolley line which furnished a great deal of amusement to many children at a minimum cost. The wire, which is 3/16 in. in diameter, was stretched between a tree and a barn across a vacant quarter block. The strength of the wire was first tested by a heavy man. When not in use the wire is unhooked from the tree and hauled into the barn and coiled loosely in the hay loft. The wire was made taut for use by a rope which was fastened to the beams in the barn. The trolley was made, as shown in Figs. 1 and 2, of strips of wood bolted with stove bolts on two grooved pulleys. The middle wide board was made of hardwood. The wheels were taken from light pulley blocks and stove bolts were purchased from a local hardware store to accurately fit the hubs. As it was necessary to keep the bearings greased, we used vaseline. This coaster made great sport for the youngsters and at no time were they in danger of a serious fall as the line was hung low and the slant of the wire was moderate. --Contributed by H. J. Holden, Palm Springs, Calif. Details of the Trolley and How It Is Used

Illustration: Details of the Trolley and How It Is Used