MABERY. — OX THE COMPOSITION OF PETROLEUM. 357 



0.8907 gram of the solid and 24.24 grams benzol gave a rise of 0°.295. 



Calculated for C.^IIij. Found. 



324 319 



TicTUACOSANE, C.jIIjo, B. P. 272°-274° (40 mm.). 



This distillate melted without purification at 50°— 51'^, which was not 

 changed by crystallization from alcohol and ether. Kraffi's tetracosane 

 obtained from the ketone derived from barium stearate and barium hep- 

 tylate melted at 51°.l. The quantity obtained of tetracosane was not 

 sufficient to determine its specific gravity. 



This hydrocarbon was shown to belong to the series CnHou+s ^y the 

 following combustions : 



I. 0.1424 gram of the substance gave 0.4451 gram CO2 and 0.1923 

 gram U.^O. 

 II. 0.1460 gram of the substance gave 0.4551 gram COo and 0.1955 



gram H.^O. 

 III. 0.1443 gram of the substance gave 0.4502 gram CO2 and 0.1924 

 gram H.^O. 



Calculated for 

 C24II-,,. 



C 85.21 



H 14.79 



The formula was verified by a determination of its molecular weight. 



3.0316 grams of the oil and 22.42 grams benzol gave a rise of 1°.034. 



Calculated for Co^IIjo. Found. 



338 335. 



Pentacosane, C05H5,, B. P. 282°-284° (40 mm.). 



The melting point of the unpurified distillate 282°-284° was 53°-54°. 

 After crystallization from ether and alcohol, it melted at 54°. 

 Its specific gravity was determined above its melting point: 



60° 0.7911 80° 0.7870 



70° 0.7881 90° 0.7854 



A combustion gave percentages of carbon and hydrogen required for 

 the formula C„Hon+2. 



