DOMESTIC MOTORS. 223 



introduction of water under pressure into buildings in cities and towns, 

 be used in very many places. As, however, the supply that most water- 

 works are capable of furnishing is not at any time greatly in excess of 

 the demand, wheels adapted for use upon house-pipes have to be, first 

 of all, economical of water. They should also be constructed so that 

 they are not liable to injury by water freezing in them, and be of low 

 first cost. Several different wheels, designed to meet these require- 

 ments, are now made, and have been more or less widely introduced. 

 One of the best of these, and one which has met with considerable 

 favor in the market, is that shown in Fig. 2, the invention of Mr. 

 O. J. Backus. It is exceedingly simple in construction, and has 

 proved very satisfactory in use. It consists of a light but strong 

 wheel, carrying buckets or vanes upon its rim, against which a jet 

 of water impinges. The wheel is inclosed in an iron casing in which 

 it revolves freely, the only points at which there is any friction 

 being the bearings of the shaft. The manner of using the water 

 constitutes the special feature of the motor, and is one that pecu- 

 liarly adapts it to use on service-pipes, as it reduces the consump- 

 tion to a minimum. In the wheels used in manufacturing, Avhether 

 of the turbine or other pattern, motion is imparted by the continuous 

 pressure of a considerable body of water. In this the motion is due 

 to the successive impacts of a small jet having a high velocity, which 

 allows of considerable work being performed with comparatively little 

 water, as the striking force of the jet is utilized. In the smaller sizes 

 of these motors, those capable of running a sewing-machine, the water- 

 jet is but one sixteenth of an inch in diameter, while in the largest 

 machines it does not exceed half an inch. A steady and uniform 

 motion of the wheel is attained by placing the buckets very close to- 

 gether, so that the impulses follow each other in rapid succession. 

 The water enters the wheel-casing at one side and escapes at the bot- 

 tom, traversing but one quarter of it. As there is nothing to impede 

 its flow, none can remain in the wheel and freeze in cold weather. 

 The motors are manufactured in sizes varying from seven to forty-five 

 inches' diameter of wheel, and from about one eighth to eight horse- 

 power. The power obtained depends of course upon the pressure of 

 the water, but they are designed to run at any pressure above fifteen 

 pounds per square inch. This is easily obtained, as at most places 

 where there are water-works there is a pressure of from twenty to 

 forty pounds, and at some a much higher one. The manner of apply- 

 ing the motor to a sewing-machine is shown in Fig. 3. Perfect control 

 over the supply of water is given by a valve operated by a treadle, 

 which enables the operator to stop and start the machine as readily 

 and quickly as by the ordinary foot-power. This method of regulat- 

 ing the speed of the machine has the great advantage that only the 

 amount of power required is at any time used, thus saving the water 

 to the utmost. 



