32 BENJ. PIKE'S, JR., DESCRIPTIVE CATALOGUE. 



ten inches long ; there is supported two electro-magnets in 

 a vertical position, with their poles upwards, the magnets 

 being covered with a double coil of thick insulated copper 

 wire, the terminations passing through the base to the under 

 side ; the magnets are held firmly clamped to the base by 

 a brass bar and screw from beneath. A small stage, sup- 

 ported by four brass pillars, through which the poles of the 

 magnets just extend, over which two armatures movable by 

 a horizontal axis attached to the stage are supported, and so 

 connected over the poles of the magnets, that, while the one 

 armature is in contact with the poles of one magnet, the 

 other armature is removed from the other magnet, and 

 vice versa. The armatures thus arranged are connected to 

 one end of a horizontal walking beam, supported on a stout 

 vertical brass column, branched at the extremity, for receiv- 

 ing the axis of the beam ; the other end of the beam being 

 connected to the crank of the spindle of a fly-wheel, sup- 

 ported by two brass pillars ; on a part of the spindle there 

 is a compound silver break-piece, against which two silver 

 springs alternately touch, the connexions being formed as 

 follows : one termination of the first electro-magnet is con- 

 nected to one of the silver springs, and the other termination 

 to the cup with binding screw at the side of the base. The 

 one termination of the other electro-magnet is connected 

 with the other spring, and the other extremity to the same 

 cup with binding screw as the first is attached. The arma- 

 tures are connected by the frame of the instrument, and a 

 wire beneath the base, to another cup with binding screw. 

 The working of the engine is accomplished by connecting 

 the cups with the wires from the ordinary pot battery (Fig. 

 391), and screwing them fast therein. The battery should 

 be charged with a fresh solution of blue vitriol, and the zinc 

 cylinder scraped clean, when the engine will work admirably 

 well, the armatures being alternately attracted by the mag- 

 nets, in consequence of the silver springs alternately acting 

 on the break-pieces of the spindle, giving rapid motion to 

 the beam and fly-wheel; the silver springs must just touch 

 the break, and be free where it is filed away, and care taken 

 that the contact is not interrupted by dirt, &c. 



Price, $12.00. 



eam Engine with Curved Armatures. (Fig. 453, next 

 page.) The description given of the preceding engine, 



