102 G. HARKER. 



A preliminary distillation of the oil up to 170° O. wa» 

 first made in an ordinary distillation flask (without still- 

 head) in order, while retaining all benzene and toluene, to- 

 separate a great portion of the higher boiling substances. 

 The oil thus obtained was washed with sulphuric acid and 

 caustic soda according to the method of Davis, as given in 

 Lunge and Keane, vol. 2, part ii, p. 767. The washed oil, 

 after standing overnight in order to complete the separa- 

 tion of water, was then distilled under the conditions out- 

 lined at the beginning, using the same round-bottomed flask 

 and still-head as for the preliminary tests. 



The paraffins present in the sample of coal tar oil were 

 estimated either in the benzene or toluene fractions separ- 

 ately, or in the combined fraction. Generally speaking,, 

 the proportion of paraffins in the benzene or toluene frac- 

 tions was about the same. The estimation was carried 

 out with anhydrous sulphuric acid. 1 



Blank tests were first carried out with pure benzene and 

 toluene, using lOc.c. of anhydrous sulphuric acid and 5c.c. 

 hydrocarbon. In both cases the hydrocarbon was rapidly 

 sulphonated and dissolved. The method was then tested 

 on a sample of light ligroin distilled up to 100° O., and on 

 mixtures of this with benzene and toluene, and found to be 

 quite reliable. In carrying out an actual determination 

 after sulphonation in a 100 c.c. cylinder, the liquid was 

 poured into a small measuring cylinder whereby the volume 

 of oil floating on top of the sulphonated liquid could be 

 more accurately estimated. 



Estimation of benzene and toluene in samples of coal tar 

 oil, marked I, II and III, from the Sydney Municipal 

 Council (Wattle Street Depot). 



Sp. gr. at 17° O. 0'928, 0*98, 1*012. 



1 Lunge and Keane, vol. 2, pp. 7P9, and Allen, 4th Ed. vol. 3, p. 241. 



