838 



Static Electricity. 



No. 60 645 



60 645. 1 : 8. 



60 646. 1 : 8. 



60 648. 1 : 6. 



60 649. 1 : 5. 



60 651. 1 : 4. 



60 652. 1 : 4. 



60.645. Apparatus for approximately determining Dielectric Constants, as suggested by Mach, s. <\. 

 Figure (M. P. 10 ttt edn., IV, 1, Fig. 212; 9 th edn., Ill, Fig. 212) 2. 6. 



60.646. 2 Lodge Leyden Jars, Figure, for demonstrating Electric Resonance (Ztschr. f. 



(1. phys. u. chem. U. 3, p. 249), 16 cm-high 1. 6. <> 



One of the jars is provided with a closing wire which contains a spark gap bounded by 2 brass 

 spheres; the other contains a fully closed circuit, which, however, is variable along its length by a 

 sliding piece of wire. In addition, the inner coating of this latter jar is connected to the outer coating 

 by a closing circuit interrupted only by a small spark gap. Both jars are placed alongside each other 

 in such manner, that the closing circuits run parallel to each other (not as shown in the above figure). 

 If now the first jar is excited with the fixed circuit by means of an induction apparatus, the second 

 jar is also discharged at each passage of the spark by the action of resonance, assuming, of course, 

 that the sliding contact occupies the correct position. Not too slight a motion of the sliding contact 

 disturbs the resonance and stops the secondary discharge. Induction is also avoided by interposing 

 a metal screen between the two jars; glass plates or wood screens have, on the other hand, no influence, j 



60.647. idem, 26 cm high .1.16.0 



60,648. Indicator (Discharge Tube) (Noack's), Figure, for demonstrating Resonance 

 Vibrations with the apparatus No. 60,646 and 60,647 (Ztschr. f. d. phys. u. chem. U. 15. 



p. 95) 



The indicator consists of an angular shaped Geissler tube which is fixed to the Lodge Jar with 

 threads instead of the spark gap, in such manner that the tinfoil coatings on both ends make good 

 contact with the metal parts of the jars. The tube is rendered luminous with each discharge. 



0. 4. 



60,649. Apparatus, as suggested by Puccianti, Figure, for the projection lantern (cf. M 



P. 10 lh edn., IV, 1, 'p. 272) 0.16.0 



A is a glass tube filled with cotton wool, this tube (icing continued as a capillary B. If air 

 bubbles are then passed through A into the vessel filled with petroleum, the bubbles are repelled by 

 the metal sphere P when this is electrified, equally so whether the electricity is positive or negative. 



60,650. Rubber Bellows for above 0. 4.0 



0. is. o 



o.o 



60,65 1 . Hauy's Apparatus for investigating the Electricity produced in Minerals by Temperat urc- 

 clianges or by 'Pressure, Figure, for fluorspar and tourmaline, with insulating stand 



60.652. Kundt's Pyro-Electric Apparatus, Figure (Wiedem. Annul. 20, p. 592, 1883; 2s. 



p. 145, 1886; Chwolson, IV, 1, p. 253) 2. 



Cl. 5685, 2195, 



2196,5025.2058,5624. 



