430 



SCIENCE 



[Vol. LVI, No. 1450 



rides in the ratio oi 20 : 7. These being the 

 principal constituents, the problem of manufac- 

 turing potassium chloride therefrom is that of the 

 separation of potassium and sodium chlorides. 

 This is accomplished by alternately evaporating 

 and cooling, the former precipitating the sodium 

 salt, and the latter the potassium salt, advantage 

 being taken of the wide difference in the tempera- 

 ture coefficients of solubility of the two. The 

 cooling is accomplished by boiling in vacuum. 

 The equilibria obtaining and their manipulation 

 for the most convenient operation of the system 

 and the manufacture of potassium chloride of 

 desired purity have been studied from the phase 

 rule point of view. Compositions at the various 

 points of concentration have been determined, 

 and methods of calculating these have been devel- 

 oped and applied to the practical operation of 

 the evaporating and crystallizing processes. 



The chemical control of the Mexican cotton boll 

 weevil: Lehman Johnson. The XJ. S. D. A. 

 method of dusting cotton plants vrith. calcium 

 arsenate is an effective means of control, but 

 difficult, beyond the intelligence and skill of the 

 average cotton farmer. None the less, in the ab- 

 sence of any easier or more successful method up 

 to this time it deserves the endorsement of the 

 American Chemical Society as an excellent piece 

 of research work and the society's encouragement 

 to simplify, standardize and make more general 

 the application of the method, probably needing 

 a special organization and a large body of trained 

 inspectors and coaches in the method. Compari- 

 son is drawn with Mississippi Eiver flood preven- 

 tion. 



DIVISION OF CELLULOSE CHEMISTRY 



Harold Hibbert, Chairman 

 G. J. Esselen, Jr., secretary 

 Chemistry of Wood — VI: Besults of analysis of 

 hearticood and sapwood of some American spe- 

 cies: G. J. RiTTEK and L. C. Fleck. The com- 

 parative chemical composition of heartwcod and 

 sapwood of ten American species is given in the 

 paper. The results show that in general the cellu- 

 lose and the lignin are higher in the sapwood of 

 the conifers, but that these same constants are 

 higher in the heartwood of the deciduous species. 

 The higher yields of loellulose and lignin in the 

 sapwood or in the heartwood of a given species 

 are accompanied by lower yields In extractives. 



The aeetolysis reaction applied to cellulose iso- 

 lated from a number of commercial woods: 

 Louis E. Wise and Walter C. Russell. Cellu- 



lose was isolated from beech, birch, maple, aspen, 

 oak, pine, balsam, cedar and hemlock by alternate 

 chlorination and sodium sulfite treatments until 

 free from lignin. The cellulose was then eon- 

 verted to ' ' normal cellulose, ' ' which was subse- 

 quently subjected to aeetolysis. In each case 

 appreciable amounts of cellobiose oetaacetate 

 were isolated and identified. 



Factors influencing the properties of wood 

 cellulose as isolated hy the chlorination method: 

 Mark W. Beat and T. M. Andrews. Certain 

 series of pulps made by keeping all cooking con- 

 ditions as constant as possible except time gave 

 values for alpha, beta and gamma cellulose that 

 did not lie in proper relation to each other. Un- 

 less the chlorination conditions are uniform in 

 the preparation of cellulose from these pulps the 

 character of the cellulose is affected. Therefore, 

 a study was undertaken of the conditions which 

 affect the character of the cellulose as expressed 

 in the per cent, alpha, beta and gamma cellulose. 

 It was found that increasing the temperature and 

 time of chlorination (over-chlorination) increases 

 the percentage of non-resistant cellulose in cello- 

 lose derived by the Cross and Bevan method. 

 There is very little beta cellulose in pulps or 

 wood before it is chlorinated for the preparation 

 of cellulose, except in decayed material. The 

 action of the organisms of decay in some cases is 

 similar to that of chlorination on the character 

 of cellulose. The copper number of cellulose is 

 a measure of the resistance of cellulose toward 

 17.5 per cent, sodium hydroxide solution, and also 

 of the amount of over-chlorination. The data 

 indicate that beta and gamma cellulose have the 

 same copper number. 



The ratio, copper number of the cellulose 



= constant. 



per. cent, beta plus gamma cellulose 



From the relation of the copper reduction capacity 

 of beta and gamma cellulose, the data indicate 

 that within every three CgHioOs complexes there 

 is one aldehyde group. 



An improved method for the determination of 

 alpha, beta and gamma cellulose: Mark W. Brat 

 and T. !M. Andrews. A volumetric method for 

 the determination of alpha, beta and gamma 

 cellulose based upon the titration of the organic 

 material in Cross and Bevan cellulose has been 

 worked out. The separation of the resistant from 

 the non-resistant cellulose is carried out by treat- 

 ment with 17.5 per cent. NaOH, filtered by suc- 

 tion or centriiuged and washed. The alpha cellu- 

 lose is dissolved in 72 per cent. H2SO4 made up 



