The vacuum calorimeter first form

The Vacuum Calorimeter f First Form.—The principle of the method underlying this apparatus is simply that the substance under examination itself serves as calorimeter and is warmed a few degrees (or even less) by a platinum 

Gaede has, it is true, used a similar method in work with metals, only without the employment of a vacuum but for the latter, the experiments here described could not have been carried out. 

In 1909 my then private assistant, Dr. A. Eucken (23), undertook, at my suggestion, the development of the above method, and he solved the problem so well that he was able to clear up all the essential points which cropped up. 

After the method had thus been shown to be quite practicable, I undertook (47), with the capable co-operation of my private assistant, Dr. Pollitzer, the further development of the method, especially for the domain of the lowest temperatures we carried out a large number of measurements, to the results of which we shall frequently have to refer. 

In Fig. 4, K is the calorimeter proper, which is hung from the two lead-in wires it is contained in a pear-shaped vessel which is evacuated as completely as possible by means of a Gaede pump, and usually also by means of cocoanut charcoal which, having been previously strongly ignited in vacuo, was cooled in liquid air. 

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