RICHARDS AND WREDE. — TEMPERATURE OF MANGANOUS CHLORIDE. 345 



It is perhaps worthy of note that manganous chloride has been found 

 by Kahlenberg, Davis, and Fowler 3 to be only very slightly hydrolyzed 

 at 56°, a temperature very near the transition temperature, 58°. The 

 hydrolysis at this temperature is not enough to cause, during the time 

 of the transition experiment, any considerable chance for the forma- 

 tion of the higher oxides of manganese by action of the air on the 

 slightly hydrolyzed solution. This is of course particularly true of the 

 highly concentrated saturated solution at 58°. 



Determination of Transition Temperature. 



Great care was taken in this work. Besides common thermometers 

 for the determination of the temperature of the thermostat, etc., three 

 instruments of great precision were used. 



These were as follows : 



1. Normal thermometer (of Jena glass, 5S m ) about 48 cm. long. 

 The scale of this thermometer extended from 0° to 100° with bulbs 

 between 5° and 18°, and between 65° and 95°. This instrument was 

 made by Richter of Berlin especially for this determination, and was 

 used in the preliminary experiments which were made to show the 

 constancy point of the purest salt. The results are given in the sixth 

 column of Table I. An accident to the thermometer prevented its 

 exact calibration, but its results are exact relatively to one another, 

 and in this respect are just as good as if this calibration had been 

 carried out. 



2. A Beckmann thermometer, No. 30, Richter (Jena glass, No. 59 1 "). 

 This thermometer was somewhat larger than usual and made with 

 great care. Its column showed an unusually slight tendency to ad- 

 here to the glass, and gave, as will be seen, extraordinarily constant 

 readings. The scale was divided into one-hundredths. All deter- 

 minations made with the other thermometers were also made with this 

 instrument, which thus served as a means of comparing and controlling 

 them. The results are given in the Tables. The particular point in 

 question, 0.508° on this scale, was standardized with great care by the 

 Physikalisch-Technischen Reichsanstalt and found to correspond to the 

 temperature 58.090° on the international standard. After it had been 

 standardized, the same thermometer was used again for determining 

 the transition temperature, and gave the same results, thus showing 

 that the mercury in the bulb had remained constant in amount under 

 the very careful treatment which it had received. 



On account of the breaking of thermometer 1, we desired to confirm 



8 Kahlenberg, Davis, and Fowler, J. Am. Chem. Soc, 21, 1, 1899. 



