VII. CONDUCTION. 275 



1085. Apparatus for Freezing Water, constructed by 

 Mr. Bieberich. Compare the adjoined instruction for use. 



University of Munich (Prof. v. Jolly). 



1086. Small Ammonia Ice Machine. 



Vaast and Littmann, Halle. 



VII. CONDUCTION. 



1091. Bespretz's Apparatus for showing the Conduction 



of Heat in metals with 9 thermometers. 



Warmbrunn, Quilitz, and Co., Berlin. 



109Oa. Three Original Bars, by Despretz, used in his 

 experiments upon the Laws of Conductivity. 



The Faculty of Sciences \ Paris. 



1038. Forbes 9 Iron Bar for Thermal Conductivity, with 

 its crucible. P ro f' Tait. 



1089. German Silver Bar, of same size, cast for same 

 purpose. Prof. Tait. 



1059. Biacalorimeter. To measure the resistance which 

 liquids offer to the passage of heat. Frederick Guthrie. 



Two conical platinum vessels, having their bases accurately plane, are sup- 

 ported so that their bases are parallel, horizontal, and nearly in contact. The 

 lower cone is fixed, and, being provided with a vertical tube fitting air-tight 

 in which water stands at a known height, serves as an air thermometer and 

 calorimeter. The upper cone can be adjusted by a micrometer screw at any 

 distance from the lower one. Through the upper cone a current of warm 

 water or steam is passed. Between the bases of the cones is introduced the 

 liquid whose thermal resistance is to be measured. 



1092. Zngenhousz's Apparatus for demonstrating the Con- 

 duction of Heat, with nine rods of different metals. 



Warmbrunn, Quilitz, and Co., Berlin. 



1093. Apparatus intended to produce the Curves of Ther- 

 mic Conductivity on the surface of bodies. 



M. Jannetaz, Paris. 



On the glass support are placed plates coated with grease, which may be 

 coloured. The current of a battery is made to pass through the small platinum 

 ball, which is at the end of wires of the same metal, and which are put into 

 contact with the plate. 



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