C. M. Warren on a Process of Fractional Condensation. 329 
of separating from petroleum, by fractional distillation, products 
of constant boiling-point. 
Such is the general character of the results obtained in the 
attempts which have been made to separate the constituents of 
such mixtures by fractional distillation. 
The treatment with strong acids, ete., as an auxiliary to the 
common method of fractional distillation, which is claimed to 
M some instances. 
the New Process.—The chief distinctive feature of my pro- 
Cess, as compared with the common one, consists I this,—that 
the Operator has complete and easy control of the temperature 
of the vapors given off in distillation; and consequently can 
4, , Since this was prepared for the press I notice that late experiments by Ber- 
thelot go to show the correctness of my conception of the value of constancy 
boiling-point, as above stated. 
