48 PROCEEDINGS OF THE AMERICAN ACADEMY. 



Here again it seems as if the agreement between different observers 

 should be better. 



The volume of propyl alcohol as a function of pressure and tempera- 

 ture is given in Table V and in Figure 10. 



At 40°, Amagat gives for the change of volume between 1 and 500 

 kgra. 0.0432, which is the value used in the table. He gives, however, 

 1.0406 for the volume at atmospheric pressure against 1.0380 adopted 

 above. It will be noticed that Amagat's value lies between those of 

 Zahnder and of Naccari and Pagliani. At low pressures and 20° 

 the changes of volume for successive intervals of 500 atmos. were 

 found to be: 0.0407, 0.0245, 0.0202, and 0.0170, against 0.0399, 

 0.0274, 0.0211, and 0.0176 of Amagat. The agreement for the lowest 

 pressure interval is better than on the average. Richards in his 

 recent paper gives a change of volume between 1 and 500 kgm. con- 

 siderably smaller than that used here, namely 0.0355 against 0.0393. 

 It should be remembered that the value used in this work for 20° 

 is founded essentially on Amagat's value for 40°, the only difference 

 being a small temperature correction determined from these present 

 data. The disagreement just noted means therefore, that the values of 

 Richards are considerably lower than those of Amagat. 



The initial compressibilities at 20°, 40°, 60°, and 80° were as follows; 

 to give the value of A F listed in the table 0.0492, 0.0,103, O.O3II8, 

 and O.O3I3O respectively; the corresponding values of Pagliani and 

 Palazzo are O.O49O, O.O3IOI, O.O3II5, and O.O3I33. The agreement is 

 good. The final values taken as a fair mean were: O.O49I, O.O3IO2, 

 O.O3II7, O.O3I3I. Rontgen has also measured the compressibility at 

 atmospheric pressure. His value for 20° would be 0.04955, judging 

 from a linear extrapolation from his values at 4° and 18°. Richard's 

 recent value at 20° is O.O4873, lower than any other of the values given 

 above. 



For Cp at atmospheric pressure we have the following values: 

 - 21° to +12°, 18.02 by Nadejdine^^; 21° to 23°, 22.99 by Pagliani;^* 

 21° to 90°, 23.55 by Lougiunine^S; and from 16.5° to 42.2°, 20.54, 

 from 20.6° to 53.4°, 21.34, from 20.4°, to 65.2°, 21.99, from 19.5° 

 to 78.5°, 22.63, and from 20.7° to 90.8°, 23.32 by von Reis. These 

 results also indicate a considerable rise of Cp with rising temperature. 



Isobutyl Alcohol. — Measurements on this were made with two fill- 

 ings of the apparatus; the first gave the compressibility and the dilata- 



23 Nadejdine, Jour. Russ. Phys. Chem. Ges., 16, 222 (1884). 



24 Pagliani, N. Cim., 11, 229 (1882). 



25 Lougiunine, Am. chim. phys., 13, 289 (1898). 



