45, CORNHILL, B.C., AND 122, REGENT STREET, W., LONDON. 



445 



FIG. 2660. 



FlQ. 2677. 



FIG. 2675. 



2672 



14 



18 



Reflecting Galvanometer, Sir W. Thomson's, with Astatic Needles, on Tripod 

 Stand, short thick wire, with Lamp-stand and Scale 11 11 



2673 Ditto ditto with about 2,500 ohms resistance . 13 13 



2674 Detector Galvanometer, with Vertical Needle (fig. 2674) 3 10 6 



2675 Sine Compass or Galvanometer, for measuring powerful 



galvanic currents (fig. 2675). For description of 



construction and use, see Ganot's Physics . Price 15 15 



2676 Quadrant Electrometer, Thomson's arrangement, suited for Lecture Table, 



will show the tension of a single cell (fig. 2676) . 4 10 



A delicate form of Electrometer for the quantitative measurement of electrical charge. The principles 

 and use of Thomson's instrument will be found in detail at page 130 of Negretti and Zambra's Treatise 

 on Meteorological Instruments. Price 5s. 



2677 Ritchie's Experiment, exhibiting the rotation of an 



electro -magnet between the poles of a permanent 

 horse-shoe magnet (fig. 2677) 



2678 Ritchie's Experiment, with adjusting Screws 



2679 Gamut of Bells on Stand, with Ritchie's Experiment, 



rotating in the centre, carrying a clapper which 

 strikes the bells in succession similar to fig. 2458, page 422 



2680 De la Rue's Electrical Discharger, a contrivance for using various 



differently prepared Carbon Points, &c. (fig. 2680) 



2681 Sturgeon's Semi- spiral Disc, for exhibiting the various 



coloured sparks evolved by different metals (fig. 2681) 



2682 Bain's Apparatus for taking Soundings at Sea by means 



of an induced magnet (fig 2682) 



2683 Magnetic Toys, consisting of fishes, ships, swans, &c., 



to illustrate magnetic attraction and repulsion each 



2684 Ampere's Apparatus, for exhibiting the rotation of a cylindrical 



Galvanic Battery round the pole of a Magnet .... 

 Horse-shoe Magnet on Brass foot, for ditto 

 De la Rive's Floating Battery (fig. 2686) . 

 Ditto ditto with elongated Helical Coil (fig. 2687 ) 



330 



220 



2 12 



400 



1 



2685 

 2686 



2687 



1 

 12 



7 

 7 



