Hi"' KKIMNUS OP T11K AMERICAN ACADEMY. 



Director of the laboratory, Professor Bmil Fischer, and to the President 

 of tin- Pliysikalisdi Technischen Reielisanstalt, Professor Warburg, for 

 their interesl in and Bupport of this investigation, and to Dr. Griita- 

 maoher of the Keichsanstalt for his prompt and thorough testing of 

 our thermometer. 



Summary. 



1. For the transition temperature of manganous chloride from the 

 tefcrahydrate to the dihydrate the point 58.089° upon the international 

 hydrogen scale has been found. This point is probably not more than 

 <UM>. r ) degree in error. 



•_'. This transition temperature of manganous chloride was found to 

 be suitable for serving as a fixed point in thermometry, on account of 

 the ease of preparation of the salt and the satisfactory defiuiteness 

 of the transition. 



.*i. In this paper is described a tall transparent thermostat which 

 makes it possible to determine exactly the temperature of the whole 

 length of the thermometer. 



FlItST ChSHIOAL iNSTITt'TK OF THE 



University of Berlin, 

 August 1, 1907. 



