96 BRIDGMAN. 



by Sonstadt,2 16.55° by Pettersson,^ 16.75° by Rudorff/ 16.75 to 



17.00° by Raoult,^ 16.59° by de Visser/ 15.62° by Abegg,' 16.54° by 



Meyer,^ and 16.68° by Faucon.^ In Table I, I have adopted the value 



given without reference in the recent edition of Stelzner, which is the 



same as the value of Faucon. For the latent heat there is 43.66 cal. 



between 2.9° and 5.6° by Pettersson,^ 46.4 at the melting point by 



Marignac/° 46.3 by de Visser,^ and 45.8 by Meyer.^ The value of 



dr 

 Table I, computed from A^ and -t' is 45.1 cal. For the change of 



volume on melting Pettersson ^ gives 0.1252 cm.^ per gm., de Visser ^ 

 0.1595, Meyer ^ 0.1578, and Block ^^ 0.1278. I find by extrapolation 

 from 78 kgm. 0.1560. The specific heat of the solid is given by Guil- 

 lot ^2 as 0.627 at 4.5°, and that of the liquid at 16.5° as 0.473 by Massol 

 and Guillot.^^ Schiff ^* gives for the licjuid the formula 0.444 + 

 O.O37O9 {t + t]). There can be no doubt but that the value for the 

 solid is erroneous. 



The effect of pressure on the melting point has been measured by 

 de Visser ^ up to 30 kgm.; he gives for the initial slope 0.02355 degrees 

 per kgm. Meyer ^ calculates from his data 0.0233 for the initial slope, 

 and I find above 0.02351. Tammann ^^ finds a considerably lower 

 value, 0.0220. The only measurements to higher pressures are by 

 Tammann, who also gives the only previous data on the transition 

 line between the two solids. His coordinates of the transition line 

 differ widely from mine. At 0° his ecjuilibrium pressure is 1145 kgm. 

 against 1074 of mine, and at 50° it is 2170 against 1994. The differ- 

 ence cannot be explained by the width of the band of indifference. 

 Tammann's melting curves both lie appreciably below mine; his triple 

 point differs by 230 kgm. and 1.8° from mine. Tammann does not 

 give the changes of volume. 



2 Sonstadt, Jahrber. Fort. Chem. 1878, 34, and Chem. News, 37, 199 (1878). 



3 O. Pettersson, Jour. prak. Chem. (2), 24, 296. 



4 Rudorff, Ber. D. Chem. Ges., 3, 390. 



5 Raoult, Ann. Chim. Phys. (6) 2, 66, 71 and 75. 



6 de Visser, Rec. Trav. Pays Bas, 12, 101 (1893). 

 7Abegg, ZS. phys. Chem., 15, 213 (1894). 



8 J. Meyer, ZS. phys. Chem., 72, 225 (1910). 



9 Faucon, quoted in the Tables of the French Physical Society under date 

 of 1910. 



10 Marignac, quoted by J. Meyer, reference (8) above. 



11 H. Block, ZS. phys. Chem., 78, 385 (1911-12). 



12 Guillot, Paris, J. B. Bailliere et fils (1895). Thesis (?). 



13 Massol and Guillot, C. R., 121, 108 (1895). 



14 Schiff, Lieb. Ann., 234, p. 322. 



15 G. Tammann, Kristallisieren und Schmelzen, p. 275. 



