262 SEC. 8. HEAT. 



1033. Thermometer Electric Alarum, for giving notice 

 when a given temperature is reached. Dr. Letts. 



The apparatus consists of an open thermometer with large bulb and wide 

 tube. A platinum wire is sealed into the bulb, and another wire passes down 

 the tube. The latter can be so adjusted that at a given temperature its end is 

 touched by the mercury in the tube. The two wires being connected with an 

 electric bell and battery, as soon as the mercury touches the wire, contact is 

 made and the bell rings. 



The apparatus was used in experiments with the glass digester, and served 

 to give notice at some distance from the room in which the latter was being 

 heated when the desired temperature had been reached, thus rendering an 

 actual observation of the temperature unnecessary, and so preventing all 

 danger in case of an explosion. 



1034. Normal Thermometer, divided in tenths of a degree 

 from to 105 C. 



Will. ffaak, Neuhaus am Renmoeg, Thuringen. 



1035. Normal Thermometer, in a narrow glass cylinder 

 with a small mercury bulb ; divided in tenths of a degree from 

 to 105 C. Witt, ffaak, Neuhaus am Rennweg, Thuringen. 



1036. Normal Thermometer, divided to tenths from 35 

 to +50 C. Will. ffaak, Neuhaus am Rennweg, Thuringen. 



1038. Two Thermometers, for chemical work, from 10 C 

 to +360. Will, ffaak, Neuhaus am Rennweg, Thuringen. 



1039. Two Thermometers, from 100 to 360. 



Will, ffaak, Neuhaus am Rennweg, Thuringen. 



1040. Two Thermometers, from to 150. 



Will, ffaak, Neuhaus am Rennweg, Thuringen. 



1041. Two Thermometers, with divisions etched on the 

 tube. Will, ffaak, Neuhaus am Rennweg, Thuringen. 



1045. Various Pressure Thermometers, on the plan of 

 Mitscherlich. See accompanying pamphlet. 



Prof. Mitscherlich, Munden. 



1046. Metallic Thermometer for Lectures, on the plan 

 of W. Beetz, constructed by Sauerwald, of Berlin. Consult the 

 adjoining description and scheme. P ro f- Bcetz, Munich. 



1047. Model of an Apparatus for measuring Tempera- 

 tures by means of Thermo-batteries. 



Dr. J. Fernet, Breslau. 



The apparatus permits the quick and trustworthy determination of the 

 temperature of the several soldered places, as well as the differences of 

 temperature of any two soldered places. 



