The diesel fraction from a hydrogenated shale oil as reported previously, proved to be a satisfactory catalytic cracking charge stock. It, however, gave a somewhat poorer product distribution than our typical heavy California virgin vacuum distillate. To improve the catalytic cracking characteristics of this diesel fraction, it was felt that the nitrogen content should be further lowered*, so the U.S. Bureau of Mines forwarded a rehydrogenated coker distillate containing .003 weight per cent nitrogen. The hydrogenation operation was reportedly carried out at 8250 F" at a pressure of 1000 p.s .. i., a hydrogen injection rate of 3,200 cubic feet per barrel, and at a liquid hourly space velocity of 1. The liquid recovery was 98 volume per cent, of which 84.1 volume per cent was in the diesel fuel boiling range, and 15.0 volume per cent was naphtha (see letter from the Bureau of Mines, dated May 1, 1<;51, File J-69A). The hydrogenated and rehydrogenated shale oil diesel fractions are not compared with each other in this report, because the rehydrogenated product was run with the new wider screen range catalyst (60-200 mesh) and at a higher reactor temperature. However, it is possible to make a valid. comparison using our standard heavy California vacuum distillate run under similar conditions as a base in the two tests. The properties of the rehydrogenated diesel and the Vacuum distillate from "60% Heavy" California crude used in this test are shown below Report No . 27 shows the properties of the hydrogenated shale oil coker distillate diesel fraction.