The piston and rod were screwed together and turned in one operation on a lathe.  The three rings were made from an old cast-iron pulley.  The cap screws were made from steel pump rods.  A piece of this rod was centered in a lathe and turned so as to shape six or more screws, Fig. 5, then removed and the first one threaded and cut off, then the second and so on until all of them were made into screws.  The rod was held in a vise for this last operation.  Studs were made by threading both ends of a proper length rod.  Make-and-break ignition is used on the engine; however, a jump spark would be much better.  The flywheel and mixing valve were purchased from a house dealing in these parts.  The water jacket on the cylinder is a sheet of copper formed and soldered in place, and brass bands put on to co v e r the soldered joints.  —­Contributed by Peter Johnson, Clermont, Iowa.

** Dripping Carburetor [208]

If gasoline drips from the carburetor when the engine is not running, the needle valve connected with the float should be investigated.  If the dripping stops when the valve is pressed down, the float is too high.  If the valve keeps dripping, then it should be ground to a fit.

** A Merry-Go-Round Thriller [209]

[Illustration:  Swinging on the Merry-Go-Round]

As a home mechanic with a fondness for amusing the children I have seen many descriptions of merry-go-rounds, but never one which required so little material, labor and time, and which gave such satisfactory results, as the one illustrated herewith.  It was erected in our back yard one afternoon, the materials being furnished by an accommodating lumber pile, and a little junk, and it has provided unlimited pleasure for “joy-riders,” little and big, from all over the neighborhood.  It looks like a toy, but once seat yourself in it and begin to go around, and, no matter what your age or size may be, you will have in a minute enough thrill and excitement to last the balance of the day.

The illustration largely explains itself, but a few dimensions will be a help to anyone wishing to construct the apparatus.  The upright is a 4 by 4-in. timber, set 3 ft. in the ground with 8 ft. extending above.  It is braced on four sides with pieces 2 in. square and 2 ft. long, butting against short stakes.  The upper end of the post is wound with a few rounds of wire or an iron strap to prevent splitting.  The crosspiece is 2 in. square, 12 ft. long, strengthened by a piece 4 in. square and 5 ft. long.  These two pieces must be securely bolted or spiked together.  A malleable iron bolt, 3/4 in. in diameter and 15 in. long is the pivot.  On this depends the safety of the contrivance, so it must be strong enough, and long enough to keep firmly in the post.  Drive this bolt in a 3/8-in. hole bored in the post, which will make it a sufficiently tight fit.  Make the hole for the bolt very loose through the crosspiece, so that there will be plenty of “wobble,”