No. 60724. 



Quadrant Electrometers. 



843 



60 721. 1 = 6. 



60 723. 1 : 6. 



60 724. 1 : 9. 



60,715. Scale for Objective Reading, 2 m long, of /paper, with wood frame and legs, divided s. d. 

 every 5 cm 0. 8. 



(in. 710. Paraffin Lamp with slotted chimney, on raised base 0. 8. 



60.717. Argand or Auer Burner with slotted chimney, on adjustabel raised base 0.15.0 



60.718. Electric Incandescent Lamp, on stand and with shielding cylinder, Figure, for 

 quadrant electrometers and mirror galvanometers 0. 18. 



The glow lamp is of the long filament type. The voltage should be given when ordering. If 

 this is not stated we supply 110-volt lamps. 



(in. 719. Demonstration Quadrant Electrometer, Figure, simple pattern, in wood house, 



well suited for teaching purposes (Stewart & Gee, Practical Physics, Fig. 114) ... 3. 4.0 



00,720. Quadrant Electrometer (Dolezalek's), Figure (Ztschr. fur Instrumentenkunde, 21, 



p. 345), for measuring small potential differences .of approx. 1 to 0.001 volt .... 8. 0. 



The needle is of a very light type, its weight with mirror being only 0.2 gram. It is suspended 

 from a quartz fibre rendered conductive by hygroscopic salts and is so formed as to be self-damping, j 

 It is charged with 50 to 200 volts. 



00,721. - - idem, modified by Wien, Figure, with tall base and platinum point, in order 

 to enable the electrometer to be charged from underneath, also with calcium chloride 

 desiccator; for measuring small potential differences of approx. 1 to 0.001 volt; with 

 amber insulation and case of Quartz Fibres 10. 0. 



60,722. Case of Quartz Fibres for Nos. 60,720 and 60,721 0. 5. 



iid.723. Quadrant Electrometer (Elster & Geitel's), Figure, with first quality insulation, 



also suitable for investigating radio-active substances (Wiedem. Ann. 64, p. 680) . . 12. 10. 



The damping, needle adjustment, torsion of the suspension device and the drying arrangement 

 (with sodium) can be regulated independently of each other. 



The instrument has variable sensitivity. A deflection of 1000 scale divisions can be attained 

 with 1 volt. 



(io.724. Cylindrical Quadrant Electrometer (Edelmann's), Figure, with cast zinc wall 



bracket (Fr. phys. Techn. II, 1, p. 98) 14.10.0 



The vane and quadrants consist of elongated cylindrical sections, the vane being adjusted by ' 

 a small magnet. Raw silk fibre suspension; vane charged by water battery Nos. 60,706 or 60,707. 

 The instrument is very sensitive and easy to manipulate. 



For Dry Piles Jor Charging Needles of Quadrant Electrometers see Nos. 60,689 to 60,700. 



Cl. 3951, 5201, 5776. 



