448 



NEGRETTI AND ZAMBRA, HOLBORN VIADUCT, B.C., 



FIG. 2701. 



FIG. 2707. 



Each. 



Each, 

 s. d. 



2706 Apparatus to illustrate the phenomena and construction 



of Primary and Secondary Induction Coils, with 



binding screw connections (fig. 2706) .... 220 



2707 Sir W. Thomson's Astatic Reflecting Galvonometer, having 4 coils, upwards 



5,000 ohms resistance, with Lamp-stand and Scale of the most recently 

 improved construction (fig. 2707) 25 



2708 Set of Shunts for above, % 5 V and ?*? the resistance of 



the Galvanometer 440 



2709 Magneto -Electric Machine, Clark's arrangement, consisting of a combination 



of highly charged permanent magnets, mounted on a stand, wilh multi- 

 plying wheel and rotating armatures, for obtaining Quantity and Intensity 

 of effects. As described in Ganot's Physics (fig. 2709) 16 16 



2710 Model Electro-Magnetic Engine, driving a small Water 



Pump . .... ...3304100 



2711 Model of Saw 'Mill driven by, Electro-Magnetism, consisting of a rotating 



armature, &c., as seen in fig. 2711 . . . .550 660 



2712 Electro-Magnetic Motive Engines, as fig. 2711, of large size, worked by the 



combination of electro-magnetic forces, and Froment's arrangement as 

 described by Ganot. Made to order. 



FIG. 2713. 



2713 Model Electro-Locomotive Engine (fig. 2713), with a 

 Straight Railway, about four feet long. The engine 

 has a self-acting reversing apparatus, causing the 

 engine to run backwards and forwards on the line ; 

 Two cells of Callan's or Bunsen's Batteries will work 

 this engine effectively. Complete, with two batteries 12 12 



