1010 



Voltaic Electricity. Section 7: Induction Currents. 



No. 62979 



62 979. 1 : 7. 



62 980. 1 : 5. 



62,989. Apparatus after Elihu Thomson, same style as No. 62,978, but considerably larger 



62.979. Apparatus after Elihu Thomson, smaller pattern than No. 62,978 and with simpler 

 fittings, Figure 



The following are delivered with the apparatus as auxiliaries: 1 thick Copper Ring with 3 Cords, 

 1 Aluminium Ring, 1 Spiral with Glow Lamp, 1 large Copper Disc, 1 small Copper Disc with agate 

 pivot, Stand and semi-circular Copper Disc, 1 Copper hollow Ring with annex tube, 1 Metal Cylinder. 



62.980. Apparatus after Elihu Thomson, Figure, simple, with 4 rings, one each wide and 

 narrow, of copper and aluminium 



This apparatus can be connected direct to a 110 120 volt lighting circuit, but a Resistance must 

 be connected up between (e. g., No. 50,521, 2. 15. 0). 



62,981. Magnetizing Ring after Elihu Thomson, 

 No. 62,978 



Figure, as addition to Apparatus 



This magnetizing ring, constructed of fine iron wire, slotted and wound, repels with a consi- 

 derable amount of force a precious-metal coin, e. g., a half-crown or five-shilling piece, which is held 

 in the narrow space between its poles, when the ring is excited by alternating current. 



With this apparatus also (which takes 5 7 amps.) use is made, as in the case of No. 62,980, 

 of a series resistance (e. g., No. 50,521, 2.15.0) when the apparatus is used on 110 120 volt A. C. 



62,666. Wehnelt Interrupter with 1 mm thick platinum pin, F i g. 62,666, p. 982, for con- 

 necting apparatus Nos. 62,978 62,981 to 65 220 volt Direct Current 



50,521. Series Resistance for above, 30 ohms, 5 25 amps. 



s. d. 

 12. 0. 



4. 4.0 



1. 8.0 



1. 0. 



3. 15. 

 2.15.0 



Prof. E. Grimsel's Apparatus for the Experimental Introduction 



of Electromagnetic Units. 



The references refer to Vol. II, No. 2 of the Abhandlungen zur Didaktik und Phi- 

 losophic der Naturwissenschaf ten : E. Grimsehl, Experimentelle Einfiihrung der Elektro- 

 magnetischen Einheiten, published by Julius Springer, Berlin, 1907. 



s. d. 



Cl. 3556, 2828. 



