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Techniques and instruments developed in this laboratory for the determination of the sizes and shapes of high-polymer molecules by the light-scattering method n-ere described in a prerious paper (a), which in the following will be referred t o as Paper S o . I. The present paper describes the application of these methods t o a study of a series of nitrocellulose fractions which has resulted in rather definite conclusions regarding the character of the nitrocellulose molecule in solution. The results obtained from the light-scattering measurements are correlated n-ith viscosity and diffusion data by the use of recently developed theories.

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The smokeless second is defined in respect to the standard falling-ball viscometer, but the solution employed contains 10 per cent by weight of nitrocellulose in a solvent consisting of 10 parts (by weight) of acetone and 10 parts of denatured alcohol. The viscosity in poises is approximately equal to this time multiplied by the factor 3.77.

at temperatures of 600°and above, the activity of the catalyst decreased much more rapidly than at the optimum temperature 575°. Very little difference in activity or life of the two catalysts reported in this paper was noted. Several other catalysts of different ratios of chromium and nickel were prepared; they also showed very little difference in activity. With space velocity ratio of 4:1 of hydrogen sulfide to ethylbenzene, only low yields (~5%) of thianaphthene were obtained.Preliminary results with other alkylbenzenes indicate that the reaction may be general, however, the yields do not appear to be as good as in the case of ethylbenzene.Acknowledgment.-The authors are verymuch indebted to the Research Corporation for a Frederick Gardner Cottrell grant-in-aid which supported this research. Summary Thianaphthene has been prepared in 18.5% conversion from hydrogen sulfide and ethylbenzene using a chromia on alumina catalyst at 575°. Claremont, Calif.