December 15, 1922] 



SCIENCE 



697 



eral ammoiiiates aud part organic ammouiates to 

 oifset this shortage; t]ie necessity of conserving 

 all waste materials carrying organic nitrogen and 

 of developing methods to render available the 

 nitrogen in such inert materials as leather, hair, 

 etc.; a description of the manufacture of leather 

 meal, its undesirability and a comparison of the 

 European and American products; a refutation 

 of the general understanding that the nitrogen in 

 the inert materials can not be made soluble with- 

 out loss of ammonia, and the reference to a high 

 class product which can be used in any quantity; 

 a discussion of garbage tankage and other waste. 



DIVISION OF PETROLEUM CHEMISTRY 



T. G. Delbridge, chairman 



W. A. Gruse, secretary 

 The vapor pressure of solutions of benzol, 

 hexane and cyolohexane in lubricating, gas ab- 

 sorbent and vegetable oils, with molecular weight 

 data: Robert B. Wilson and Edward P. Wtlde. 

 A knowledge of the vapor pressure of volatile 

 solvents, such as benzol and hexaue, dissolved in 

 various types of relatively non-volatile oils, is of 

 commercial importance in a considerable number 

 of applications. Of these the three most im- 

 portant are (a) the dilution of crank-case oils 

 with fuels in internal combustion engines; (&) 

 tJie complete removal of volatile solvents from 

 oils and fats obtained by the solvent extraction 

 processes; and (c) the recovery of solvents by 

 scrubbing with cold absorbent oils, as in benzol 

 recovery from coal gas. It was the object of the 

 work described in this paper to make possible 

 such generalizations and approxrimate calculations 

 for the three general types of volatile hydrocar- 

 bons — paraffin, napthene, and aroma;tic — dissolved 

 in most ordinary types of oils. Molecular 

 weights were determined on all of the oils used, 

 and the amount of vapor pressure lowering for 

 different combinations was compared with the 

 theoretical as predicted by Eaoult's law. It ap- 

 pears that the amount of lowering produced by 

 different types of combinations is fairly definitely 

 predictable and that the re.sults for any com- 

 bination met with in practice can be calculated 

 with quite satisfactory accuracy for any ordinary 

 temperature if the vapor pressure of the pure 

 volatile constituent is accurately kno'ivn, together 

 wiith the molecular weight and type of hydro- 

 carbons present in the oil. Molecular weight data 

 included in the article is also of interest in being 

 the first published data on a fairly wide range of 

 the higher mineral oil fractions, the results hav- 

 ing been obtained by measuring the freezing point 

 lowering in benzol. 



Further data on the measurement of the 

 effective volatility of motor fuels: Egbert E. 

 Wilson and D.4.Nn:L P. Barnard, 4th. This paper 

 is an extension of the work presented at the Eoeh- 

 ester Section where some new methods of deter- 

 mining the effective volatility were described and 

 the results on three typical fuels presented in 

 some detail. This work has been extended to 

 more tlian a dozen fuels in this laboratory and 

 this, combined with data obtained in other labora- 

 tories, makes it possible to draw certain general- 

 izations as to the effect of the shape of the dis- 

 tillation curve on the effective volatility of the 

 fuel in so far as it affects the completeness of 

 vaporization and proper distribution in the mani- 

 fold. In the light of these investigations, the 

 writers believe that a single specification for the 

 85 per cent, point should replace all the present 

 limitations at 50, 90 and 96 per cent., and, simi- 

 larly, that the effective starting volatility can 

 best be measured as a routine proposition by a 

 specification at the 25 per cent, point rather than 

 at the 5 per cent, or initial point. 



Some applications of vapor pressure measure- 

 ments: Harold S. Davis. An improved differen- 

 tial-pressure apparatus for measuring vapor 

 pressure is described. The apparatus can be suc- 

 cessfully applied to the control of light oil recov- 

 ery plants. Actual data from plant tests are 

 given. It has been suggested that oils could be 

 standardized for efficiency in gas absorption by 

 preparing solutions containing the same concen- 

 tration of benzene and measuring their vapor ten- 

 sions. Experiments on seven representative ab- 

 sorbent oils have shown no appreciable differences 

 between them in this respect, and practical varia- 

 tions in their efficiencies must be attributed to 

 other factors rather than to their ability to lower 

 the vapor tensions of dissolved benzene. Some 

 applications of vapor pressure measurements in 

 gasoline recovery are discussed. 



A rapid test for the decolorizing efficiency of 

 fuller's earth: Leon W. Parsons and Leonard 

 E. Churchill. The paper covers the develop- 

 ment of a rapid test for determining the relative 

 efficiencies of various samples of fuller's earth 

 for decolorizing purposes. This test was desired 

 to avoid the necessity for resorting to tedious 

 filtration processes in the laboratory to determine 

 the quality of the clay, and it serves two pur- 

 poses: first, to compare the decolorizing power of 

 various clays used in experimental investigations ; 

 and second, to serve as a rapid control test for 

 plant operation. A survey of the properties of 

 fuller's earth which would parallel its power to 



