45, CORNHILL, B.C., AND 122, REGENT STREET, W., LONDON. 451 



FIG. 2734. 



INDUCTION COILS, VACUUM TUBES, Ac. 



2727 Rhumkorff Coils, of small size 



2728 Ditto ditto with Commutator .... 



2729 Ditto ditto 



2730 Ditto ditto 



2731 Geissler's Vacuum Tubes, small size, various forms, 



each 2s. 6d. 5s. 



2732 Geissler's Tubes, a set of four medium size, for use 



with the above coils ....... 



2733 Whirling Apparatus for Gassiot's Star, for small 



Vacuum tubes 



2734 A Set of Apparatus as fig. 2734, including one 



small Rhumkorff's Induction Coil, one Bichromate 

 Battery, and one Vacuum Tube on stand . 



2735 A Set of Apparatus, consisting of one Induction 



Coil, one Bichromate Bottle Battery, five small 

 Vacuum Tubes of various designs, and a "Whirling 

 Apparatus, with connecting wires, in Pine Box 



2736 Electro-Motive Engine, arranged for rotating small 



Geissler's Tubes, an exceedingly interesting and 

 attractive model, the movement and the light being 

 entirely produced by Electrical Agency 



2737 Negretti and Zambra's Improved Large Sized 



Rhumkorft's Induction Coil (Inductorium of the 

 German Physicists) to give 3i-inch spark in air 

 (fig. 2737) 



2738 Ditto ditto to give 2^-inch sparks 



2739 Ditto ditto to give 1-inch sparks 



2740 Ditto ditto small size, ^-inch sparks . 



2741 Grove's Batteries for above, see page 431. 



Each. 

 s. 



330 



Each. 

 s. d. 



150 

 1 12 



220 

 440 



070 10 6 



110 

 1 16 



3 10 



660 



440 550 



15 15 

 12 12 



10 10 

 550 



2o2 



