224 SEC. 8. HEAT. 



may be very open at its top ; it opens out into a large chamber, which receives 

 the superfluous fluid at the time of observation. 



A tin case, capped at both ends, prevents the access of extraneous rays to 

 the bulb of the instrument at the time of observation. 



1027. Original Spirit Thermometer, of the Florentine 

 Accademia del Cimento (17th century). 



The Royal Institution of Great Britain. 

 Presented to the Eoyal Institution by Sir Henry Holland, Bart., F.E.S. 



1028. Drawings, various, partly new, of constructions of 

 Differential Atmospheric Thermometers. 



Dr. Leopold Pfaundler, Professor of Physics at Innsbruck. 



This plate presents a general view of all possible forms of construction, 

 which partly appear as modifications of Berthelot's atmospheric thermometers, 

 partly are based on independent principles. 



For further details, see Transactions of the Imperial Academy of Sciences at 

 Vienna, Vol.LXXIL, 1875. 



1029. Melloni's Thermo-Electric Apparatus. 



M. Ruhmkorff. 

 1029a. Line File for Spectrum and Galvanometer. 



M. Ruhmkoijf. 



1030. Galvanometer for Thermo-Electric Currents. 



Luizard, Paris. 



1031. Pyrometers and Thermometers. 



Conservatoire des Arts et Metiers, Paris. 



1032. Collection of Thermometers. 



Dr. H. Geissler, Bonn. 



1033. Thermo-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. JHaak, Neuhaus am Rennweg, Thuringen. 



1035. Normal Thermometer, in a narrow glass cylinder 

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

 to 105 C. Will. Haak, Neuhaus am Renmveg, Thuringen. 



