METHODS OF ESTIMATING THE TEMPERATURE. 



copper, hollow cylinder, upon which the wire of the coil is wound. This mass of 

 copper may be considered as a closed multiplicator of a single winding with a large 

 cross-section. The magnet set into oscillation induces in this closed copper 

 mass a current whose intensity is greatest when the rapidity of oscillation of the 

 magnet is greatest, and which takes the opposite direction as soon as the mag- 

 net is reversed. In lesser degree the multiplicator itself as soon as it is closed 

 operates in the same manner as a damper. The currents thus induced cause a 

 reduction in the oscillations of the magnet in such a way that the arc of move- 



FIG. 135. Diagrammatic Representation of Thermo-electric Apparatus for the Measurement of Temperature. 



ment diminishes in rapid and almost geometric progression. The induced, damp- 

 ing current is the stronger the less the resistance in the closed circuit, in the 

 presence of the damper therefore the greater the transverse section of the copper 

 ring. By means of this damping arrangement the monotonous oscillation of the 

 magnet to and fro is limited and the latter comes to rest rapidly and promptly 

 after three or four small oscillations while the observation is sharp and made 

 without loss of time. 



So-called Dut rochet needles (II) are introduced as thermo-electric elements. 

 These consist of German silver and iron and are soldered together longitudinally 



