No. (il ::<>:!. 



Moving Magnet Galvanometers. 



877 



61302, 50119 and 61310. 1 : 10. 



61 303. 1 : 6. 



If the two coils are connected in opposition a differential galvanometer results. 



If the second magnet is moved into the upper half of the suspension an astatic galvanometer j 

 is obtained. 



The galvanometer has a scale divided every 10 for the scholars, a second scale, divided in single 

 degrees, being provided for the teacher. As the pointer is arranged to rotate relatively to the magnet, 

 its point can always be directed towards the scholars after the winding plane of the coils have been 

 placed in the magnetic meridian. 



Sensitivity with one magnet -- e. g., without astaticity - - with coils in series: 1 deflection 

 = approx. 0.00004 ampere. Each coil has a resistance of about 3.5 ohms. The sensitivity is ample 

 for all ordinary school experiments. 



61.300. Tangent Galvanometer Ring for above, of copper, on wood tripod, the baseplate of 

 the galvanometer fitting and rotating about the round top of this tripod, cf. Fig. 61,300 A 



Set up as a tangent galvanometer the instrument is suitable for measuring currents to 15 amperes 

 (10 amps. = approx. 60 deflection). 



For accurate reading the large pointer is changed for another intended for reading the fine scale. 



61.301. Accessories for carrying out magnetometrical measurements in conjunction with 

 No. 61,299, cf. Fig. 60,127, comprising: Aluminium Case with marks for taking 20 gram 

 brass weights for determining the moment of inertia; Graduated Slider; Bar Magnet; 

 Table for the Galvanometer and Graduated Bar with Measuring Wire, which can be 

 used at the same time as a Wheatstone Bridge 



61.302. Reflecting Galvanometer, Weinhold pattern, Figure (W. D., Figs. 508, 509 [481, 

 482]), cf. also Fig. 61,303, for setting up permanently on wall bracket or suspended 

 board, with one coil having two different windings. Price exclusive of suspended 

 board and lamp , 



The galvanometer has a Topler adjustable air damping arrangement, astatic needle with pointer 

 reading, mirror for reading by lamp and scale, transmission chamber with lens and one coil, the latter 

 being provided with one group of windings of thick wire (approx. resistance 0.5 ohm) and one group 

 of fine wire (approx. resistance 500 ohms). The ends of both windings are carried to three terminals, 

 the latter being connected by three wires and three terminals alongside the lecture table. If required 

 the thick or fine winding can be used in this manner and without altering anything on the galvano- 

 meter. The precise resistance of the two windings is given on the coil. The following sensitivities 

 are obtained with a medium period of swing (about 20 seconds for the complete period): 1 mm de- 

 flection at a distance of 1 m == approx. 1.5 xlO 8 amp. or approx. 7 xlO-' amp. 



61.303. --idem, Figure, with two coils, one with thick and one with fine winding; 

 with change-over switch so as to enable the groups of windings to be put in series or 

 punillel 



1.10.0 



3. 10.0 



10.0 



9. 0.0 



Cl. 1'324, (104. 



