588 



Thermoscopy. 



NIL ,04950 



54 951. 1 : 9. 



54952. 1:7. 



54 953. 1 : 8. 



54 954. 1 : 6. 



Thermoscopes after Galilei and Drebbel: see Xos. 54,792 and 54,793. 



54,950. Thermoscope after Weinhold, Figure (W. D. Fig. 368 [348]), very sensitive in- 

 strument for radiation experiments 



54,951. Aneroid Thermoscope, 

 sensitive apparatus . . 



Figure (Ztschr. f. d. phys. u. chem. U. 3, p. 141), very 



s. d. 



0. 3.0 



2.10.0 



54,952. Leslie's Differential Thermometer, Figure, with detachable ground-on bulbs for 

 automatic filling (M. T., p. 142), with a blackened bulb; also for use for measuring the 

 intensity of radiant heat (M. P. Ill, Fig. 82 [II, 2, Fig. 81]) 0. 10. 



54,953. Dilatation Thermometer after Rumford, Figure (M. P. Ill, Fig. 83 [II, 2, Fig. 82]), 



with short liquid threads, with detachable bulbs and glass stopcocks o. Ki.o 



54,953 a. - - i d e m, after Friedr. C. G. Miiller, with connecting tube and cock for equalising 



pressure (M. T., Fig. 100) 0. If., o 



54,954. Differential Thermoscope, Figure, with detachable ground-on glass bulbs, a glass 

 bulb with wire spiral and terminals, Figure, for experiments on the thermal effects 

 of the electric current; and two glass bulbs, each with one bismuth-antimony rod and 

 terminals, Figure, for proving the Peltier effect 1.15.0 



For shewing the thermal effect tln> l>ull> with wire spiral is placed on one end of the tlienno- 

 scope, the. other being left open, and a supply of 2 4 volts together with a regulating resistance is 

 connected In the terminals. For showing the 'Peltier effect the two bulbs with the I>ismu1h-antimon\ 

 rod are placed on the t hennnscopc. the poles of the same name, e. g.. the nicUelled terminals of the 

 bismuth, which are connected up by a lead and two accumulators in series, loget her wit h a regulating resi 

 Matice and a pole commutator, being connected up to the free end. In one gl;:s> luilli heat in;: takes 

 place when the current direction is from bismuth to antimony, a cooling effect taking place in the other. 

 By 7-cvcrsing the current the opposite effect ensues. The current density should be aUmt r> amps. Too 

 high a current generates too much heat in the rod and should be avoided. 



CI. I/IS. 6123, 



f.'l. :C53. 



