"Viscosity breaking run No. 38 was conducted over a period of 84 hours, beg1nn1ng on September 10, 1951. The primary purpose of this run was to produce a fairly large quantity of visbroken crude oil for use as charge stock in subsequent cracking operations. Secondary purposes were (a) to observe the effects of the operating conditions chosen, and (b) to study the characteristics of the combined liquid product produced Run No. 38 was a once-through operation using crude N-T-U shale oil as charge stock with a heater outlet temperature of 92Sf. and a pressure of 200 p.s.i.g. The absorber was used to insure the best possible total liquid recovery. The desired quantity of combined liquid product was produced in the run. This material had Saybolt Universal viscosity at l130 F. of 111 seconds and. a Conradson carbon of 6.5 weight percent. The pour point was around 15 F. It was observed that ''idle variations in pour point could be obtained on identical samples and that the pour point appeared to increase with the age of the sample. No particular operational difficulties were encountered in the run. Some coke deposition occurred in the heater, however, and the heater inlet pressure increased gradually over the entire period of the run."