584 PROCEEDINGS OF THE AMERICAN ACADEMY. 



agreement with the others. Probably, as Stohmann pointed out, the 

 results with the Universal Burner were too high. 



Stohmann ^ obtained most of his values for benzol by combustion in 

 a different kind of lamp. Subsequentlj'',^ however, he sealed benzol in 

 very thin glass bulbs which were placed in the bomb and broken by 

 shaking just before the bomb was placed in the calorimeter. This 

 method involved a necessary correction for the benzol burned as vapor. 

 Stohmann thus secured two results concordant with those previously 

 obtained, but he had much difficulty on account of the incomplete 

 combustion of the benzol. Of a series of determinations, he obtained 

 only these two which were not vitiated by the deposition of soot on 

 the interior of the bomb. 



In order to burn completely a weighed quantity of liquid benzol 

 without applying a correction for vaporization, the follo'wing procedure 

 was followed in the present investigation. Thin glass bulbs of about 

 0.7-0.8 milliliters with bent capillary stems were weighed, and filled 

 with benzol by immersing the stems under benzol, alternately cooling 

 and warming the bulbs in cold and hot water. The thin walled capil- 

 lary stems, filled with benzol, were sealed off near the bulbs in a fine 

 blowpipe flame. In this way bulbs could be obtained either com- 

 pletely filled or with a negligible amount of vapor in the short capil- 

 lary stem.7 The bulbs and the detached capillary stems were weighed 

 together under the same conditions as the empty bulbs, and the 

 weights of benzol thus determined. 



For combustion one of these bulbs was placed upon the top of about 

 0.25 gram of carefully weighed pure sugar in the combustion crucible, 

 and the rest of the procedure was exactly the same as in the case of 

 cane-sugar. The great heat of the burning sugar caused the bulb of 

 benzol to burst with the consequent immediate combustion of the 

 benzol. In the preliminary trials small patches of soot due to incom- 

 plete combustion of the benzol were noticed on the crucible and on the 

 lining of the bomb. This inadmissible complication was traced to the 

 fact that the stems of the bulbs were from one to two centimeters in 

 length. After sealing new bulbs in such a way that the stems were 

 only three to five millimeters long, no trace of soot ever appeared. 

 Some idea of the temperature in the crucible at the moment of com- 

 bustion may be gained from the fact that after a combustion the glass 



Jour. f. prak. Cliom., 33, 241 (1886). 



6 Ibid., 40, 77 (1889). 



' This method of enclosing liquids in thin bulbs in such a way as to be capa- 

 ble of subjection to high pressure was first used by Richards and Stull in their 

 work on Compressibility (Carnegie lust. Pub., 7, 1903). 



