432 



SCIENCE 



[Vol. LVI, No. 1450 



marized as follows: When solutions of these 

 compounds are mixed in stoichiometrical propor- 

 tions, precipitation of alumina and rosin is com- 

 plete. When a considerable excess of aluminium 

 sulfate is used the precipitate contains no resinate 

 but consists of free rosin acids with less than 

 their equivalent of free alumina. At certain con- 

 centrations all the alumina remains in solution, 

 rosin acids only being precipitated. Eosin acids 

 precipitated in this way ("Kosin B") are not 

 in the same physical condition as when precipi- 

 tated by mineral acids. Addition of mineral acids 

 to this modification of rosin changes it to the 

 more common form ("Eosin A"). "Eosin B" 

 is probably spongy rosin very thoroughly inter- 

 nenetrated with water. 



Notes on the rosin-sizing of paper. II. The 

 process in the heating engine and at the wet end 

 of the paper machine: Alfred Tingle. As com- 

 monly carried out the reaction in the beater re- 

 sults in the deposition of rosin in the form of 

 "Eosin B" (see preceding paper) on the fibre 

 with less than its equivalent of alumina. Most 

 or all of the remaining free alumina is precipi- 

 tated as the result of subsequent dilution. That 

 alumina plays no essential part in the sizing is 

 shown by the fact that paper can be successfully 

 sized under such conditions that no alumina can 

 be deposited. Eosin acids can be precipitated 

 even by sulfuric acid in a condition closely resem- 

 bling "Kosin B" if at the same time another 

 precipitate is formed which vrill serve to keep 

 the rosin finely divided. In such circumstances 

 the rosin has sizing power. Investigation of the 

 changes in size as paper dries are required. 



New methods for measuring the effects of tem- 

 perature and humidity on the dimensions of 

 paper: Haeold S. Davis. Where paper is used 

 for printing purposes its expansion or contraction 

 between imprints may cause blurring. It is, 

 therefore, of great importance to have a knowl- 

 edge of the magnitude of the changes in dimen- 

 sion and of the rates at which they take place. 

 A new apparatus is described in which the 

 humidity and temperature are susceptible to easy 

 control and in which the changes in dimensions of 

 different samples of paper may be accurately 

 measured. 



Copper n-umiers of cotton linters: W. P. Hen- 

 derson. A brief description of the source and 

 properties of the material used is given. Samples 

 were treated with various kiuds of acids of 

 increasing concentrations, and after washing and 

 drying the copper numbers of the linters were 

 determined. In the cases of strong acids a rapid 



increase was noted in the copper values, but in 

 the cases of weak acids very little change oc- 

 curred. Alkalies were used in the same manner, 

 and while the absorptive power of the linters 

 increased, the reducing power remained prac- 

 tically constant. Curves are shown for each series 

 of determination. 



Change of viscosity in viscose: W. F. Hender- 

 son. Linters were treated with increasing con- 

 centrations of nitric acid under uniform condi- 

 tions and afterwards the samples were, washed 

 and dried. These products were converted into 

 viscose under exactly similar conditions, and the 

 viscosities of the solutions were measured. A very 

 sudden drop in viscosity was noted as is indi- 

 cated by a curve which is to be shown. 



The determination of the viscosity of cupro- 

 ammonium solutions: W. O. Mitscherling. 



The manufacture of standard cellulose: W. O. 

 Mitscherling. 



Eeport of committee on the preparation of 

 standard cellulose. 



Seport of committee on analytical methods. 

 I. Methods of analysis of cotton cellulose, 

 lieport of viscosity committee. 

 Symposium on the nature of loood cellulose: 

 Louis Wise, B. Johnson, J. T>. Eue, E. C. Shee- 

 EARD and others. 



Adsorption of salts hy cellulose: Wilder D. 

 Bancroft. Though they merge one into another, 

 we can consider four cases — miscellaneous salts, 

 bases and acids, mordants and substantive dyes. 

 (1) We get a water-ring in filter paper with salts 

 of copper, lead, mercury, etc. We get peptization 

 of cotton by ammoniaeal copper oxide, zinc chlo- 

 ride, barium iodide, etc. (2) Barium, strontium, 

 calcium and lead hydroxides may be adsorbed so 

 strongly by filter paper from dilute solutions as 

 to introduce analytic errors. In mercerization 

 caustic soda is adsorbed and changes the struc- 

 ture of the cotton; but no compound is formed. 

 Jliueral acids show no appreciable adsorption at 

 moderate concentrations by titration method. (3) 

 Cotton takes up alumina and chromic oxide only 

 from colloidal solutions. In presence of tannin 

 alum is decomposed. Tannin is adsorbed ; but 

 must be fixed by antimony, because it is peptized 

 so readily by basic dyes. (4) Sodium and barium 

 salts of substantive dyes are adsorbed as such. 

 Being colloidal solutions the adsorption is 

 increased by electrolytes which decrease the sta- 

 bility; and is decreased when these electrolytes 

 coagulate the dye. 



Chaeles L. Parsons, 



Secretary 



