444 



NEGRETTI AND ZAMBEA, HOLBORN VIADUCT, E.G., 



FIG. 2664. FIG. 2666. FIG. 2668. 



2664 Soft Iron Electro or induced Magnets, consisting of a bent bar of soft iron, 

 co vered with insulated copper wire, forming,in connection with a galvanic 

 battery, a powerful electro -magnet capable of supporting a great weight 

 (fig. 2664) 5s. 6d., 14s , 110 1 10 



Soft Iron Electro-Magnet, mounted on a tripod stand 110 1 10 



Soft Iron Electro-Magnet, large size, for sustaining 



immense weights, with Tripod, &c., as fig. 2666 . 3 10 



Galvanometer, simple form, for measuring the force of 



electro- magnetic currents . . . . . .0150 110 



Galvanometer, with Astatic Needles, of low resistance, for Thermo-Electrical 

 experiments, and for measuring the conductivity of wires, with levelling 



2665 

 2666 



2667 

 2668 



2669 

 2670 



2671 



2 10 



screws to glass shade (fig. 2668) .... 

 Ditto ditto with attached Mirror 

 Galvanometer, with Astatic needles, index torsion key, 

 movable coil, and levelling screws, very delicately 

 adjusted with mirror about 1,500 ohms resistance (fig. 2670) 

 Galvanometer, with an extremely fine and long coil of 

 wire, as used by Du Bois Raymond in his researches 

 on existence of electrical currents in animals (fig. 2671) \ 



3 

 10 



10 



15 15 



FIG. 2676. 



FIG- 2670. 



