Rotary Lawn Sprinkler: a Barker's-Mill Head Turning on Balls Round the Supply Pipe (Gibbs, 1901)

"It being only necessary that certain of the orifices shall discharge the water tangentially to revolve the head 14 and spray-pipes 15 in the well-known manner."

Chuck a length of steel pipe (his pipe 13) and finish its top end smooth and round. Cut a half-round groove (his 17) round it a little below the end, to the depth the notebook gives, with a round-nosed tool. Use thick-walled pipe, so at least 1.5 mm of wall is left under the groove (ours).

Turn a brass bar to a short round head (his 14). Bore it from below to loosely fit the pipe end, his bore 16, but stop short of the top so a lip (his flange 22) overhangs the pipe end. Cut a matching groove 18 inside the bore at the same height as the pipe's groove.

Drill a hole (his opening 20) through the head's side into the groove, just bigger than a ball, and tap it for a screw plug (21). Drill three holes round the head into the bore for the spray pipes.

Cut three lengths of copper tube, close their outer ends, and bend the last bit of each upward as his Fig. 1. Drill small holes near the ends, some pointing sideways (tangentially), all the same way round, so the jets turn the head. Solder the pipes into the head's holes (ours; he threads them in).

Slide the head onto the pipe end with the grooves level. Feed balls in through the side hole, turning the head, until the race is full; then screw in the plug. The head should spin freely and not lift off.

Bore a hardwood block to hold the pipe upright and glue in three splayed dowel legs (ours; his base 10 and supports 11). Screw the hose coupling onto the pipe's lower end below the block (his coupling 12).

Connect a garden hose and turn on the water slowly: the jets push the head round and throw the water in a circle. More pressure turns it faster.

**Henry Gibbs** of Chicago, assignor to W. D. Allen Manufacturing Company, US 683,645, dated 1 October 1901, filed 20 May 1901. He claimed a single-piece hollow coupling with radial spray pipes having tangential orifices, a bore loosely fitting the supply pipe, "annular grooves in the opposed cylindrical faces of said bore and said pipe" and "bearing balls interposed in said grooves". He gives no sizes or metals; the brass, steel pipe, ball size, soldered copper arms and the wooden stand are ours.