450 



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



THERMO-ELECTRIC APPARATUS. 



FIG. 2721. 



FIG. 2722. 



FIG. 2724. 



2721 Rectangular Wire Frames, with four branches com- 



posed of dissimilar metals, with a fine point on the 

 rectangle, for suspending on the pole of a magnet, to 

 show thermo-magnetic rotation (fig. 2721) . 



2722 Compound Frames and Wires of the various metals, for 



exhibiting thermo-electric rotations (fig. 2722) from 



2723 Thermo-Rotating Compound Rectangular Frames, 



composed of platina and silver wires, mounted on a 

 horse-shoe magnet, complete, with spirit lamp (fig. 2723) 



2724 Compound Bar of Antimony and Bismuth, mounted 



on a Brass Stand, for producing a Thermo-Electric 

 current by the application of Heat to the extremity(fig. 2724) 



2725 Melloni's Thermo-Electric Pile (fig. 2725) . . .22 



Each. 

 s. d. 



FIG. 2723. 



Each. 

 s. d. 



15 6 



12 6 



1 10 



FIG. 2725. FIG. 2726. 



2726 Melloni's Thermo-Electric Pile or Battery of 25 pairs 

 of small bars of Antimony and Bismuth, in a con- 

 venient frame on a foot, with binding screws for 

 connections fitted with cones, as used by Professor 

 J. Tyndall, F.R.S., in his experiments with Caloric 

 (fig. 2726) . , . 



440 



