INDUSTRIAL AND ENGINEERING CHEMISTRY 179 acid dispersions and the great effect of fine materials further strengthened this conclusion. Conclusions1. The length of the fluid stage, in the reaction between concentrated phosphoric acid and Tennessee brown phosphate rock, decreases with increase in initial acid temperature in the range 50-250°F. (10-121°C.). It also decreases with increase in acid concentration in the range between 60 and SO per cent H3PO4. Between 80 and 85 per cent H3PO4, a minimum fluid stage is observed.2. The length of the fluid stage is proportional to the average particle diameter in closely sized rock samples, and the time required for the mixture to become dry is approximately proportional to the square of the average particle diameter. In rock samples with two predominant ranges of particle sizes-i. e. mixtures of fine and coarse materialsthe fine material causes a shortening of the fluid stage slightly more than its proportion would indicate, and also causes a, much more pronounced shortening of the plastic stage.3. The fluid stage is longer for rock samples of high P206 content than for lower grade materials.4. The length of the fluid stage, while affected by the rate of the chemical reaction between the phosphoric acid and the constituents of the phosphate rock, depends primarily upon physical phenomena, such as the absorption of the liquid by the solid phase.

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An Efficient Synthetic Route to Ethyl 2-Aryl-4-hydroxy-1,3(2H,4H)dioxoisoquinoline-4-carboxylates.-In connection with a research on herbicidal and plant growth regulating (PGR) dioxoisoquinolinones, a series (10 examples) of title compounds (VIII) is prepared. The C-4 ester moiety can be introduced by the base promoted reaction of (III) with the chloroformate (IV) or in a more unconventional matter via the phenylcarboxamide derivatives (X). Compounds (VIII) exhibit significant levels of PGR activity for the production of hybrid wheat as well as for crop yield enhancement in soybeans, sugar beets and cotton. -(SEMPLE, J. E.; RYDZEWSKI, R. M.; GARDNER, G.; J.