DAVIS. — THE LAW OF CORRESPONDING STATES. 



249 



also the corresponding "reduced " pressures and temperatures. These 

 values of the coefficient are plotted as open circles in Figure 6. 



The experiments of Griessmann were performed in the mechanical 

 engineering laboratory of the " Technische Hochschule " in Dresden, 

 and were published in 1903. They were primarily undertaken to test 

 the heat of gasification hypothesis already mentioned, and are a critical 



Figure 3. Griessmann's throttling curves. Abscissae are pressures in kg. 

 per sq. cm. Ordinates are Centigrade temperatures. From his paper in the 

 Forschungsarbeiten. 



repetition of Grindley's work. The data are given in full in the paper 

 in the Forschungsarbeiten, and are plotted in his Figure 7, which is 

 reproduced here as Figure 3. He records 13 runs with 87 sets of low 

 side observations, which with the 13 high side observations give 100 

 points on his diagram. Of these, three points on curve 2, one point 

 on curve 7, three points on curve 8, and three points on curve 9 lie so 

 far off the smooth curves determined by the neighboring points that 

 they have arbitrarily been omitted from these calculations. The re- 

 maining 90 points, lying on 11 curves, have been grouped in 44 means 



