September 3, 1920] 



SCIENCE 



231 



to tie swelling of the colloidal cellulose which has 

 received an electrolytic charge from the hydroxyl 

 ions in the water in which it is immersed. The 

 hydrolysis is (the direct result of the presence of 

 the electrolyte ions whose primary effect had been 

 hydration. The formation of oxycellulose is prob- 

 ably preceded by the hydrolysis of the cellulose 

 whereby the CO group is rendered more attackable 

 for the oxygen. The solution by zinc chloride is 

 due to the peptization of the cellulose by the ad- 

 sorbed ions with the formation of a viscous emul- 

 sion. The union between cellulose and dye is due 

 primarily to adsorption. 



The determination of cellulose in woods: S. A. 

 Mahood. a uniform size of particle appears to be 

 essential if comparable results are to be obtained 

 in the determination of cellulose in woods. Ma- 

 terial which passes an 80-mesh standard sieve but 

 is retained on a 100-mesh sieve has been found to 

 be most satisfactory from the standpoint of both 

 yield and manipulation. Maiterial obtained by a 

 single mechanical process of disintegration may 

 give a sample on sifting which is not representa- 

 tive. To avoid this a combination of two processes, 

 sawing and grinding, has been used. The appa- 

 ratus recommended by Sieber and Walter for use 

 in chlorination appears to give a lower yield of 

 cellulose than the original Cross and Bevan method 

 probably because of the temperaiture at which 

 chlorination takes place. 



Nitrocellulose from wood pulp: E. G. Wood- 

 bridge, Jr. Due to shortage of cotton, Germany 

 was obliged early in the world war to use wood 

 cellulose in place of cotton for making smokeless 

 powder. Up to about July, 1918, it was not antic- 

 ipated that any wood cellulose would be required in 

 the U. S. in spite of the enormous production of 

 smokeless powder proposed for the balance of 1918 

 and for the year 1919. However, the shortage in 

 the cotton crop, due to the drought in the summer 

 of 1918, would have made it necessary to have 

 supplemented the short-fibered cotton by wood 

 pulp had the war continued. This emergency had 

 been foreseen and experiments had been in prog- 

 ress for several years on the question of nitrating 

 wood cellulose for smokeless powder manufacture. 

 These experiments showed that a mixture of cotton 

 and wood pulp containing up to 50 per cent, of the 

 latter could be nitrated, purified and made into 

 smokeless powder without any important change in 

 equipment, with no serious loss in production, and 

 with no change in the quality of the smokeless 

 powder. 



Notes on the manufacture of nitrocellulose : J. O. 

 Sm.4x,l and C. A. Higgin. In selecting a cellulose 

 to be used for nitrating, attention should be given 

 to both its chemical and physical properties. The 

 biological character of the crude fiber and its 

 purification are the chief factors influencing the 

 chemical properties of a cellulose, while the physi- 

 cal properties comprise cleanliness, color and type 

 of fiber. From the chemical analysis of a cellulose 

 much may be learned concerning previous treat- 

 ments and its subsequent behavior when nitrated. 

 The most important tests are (1) solubility in 

 sodium or potassium hydroxide, (2) furfural con- 

 tent, (3) ether-extractive matter. Nitrocellulose 

 for explosives must pass rigid stability tests. 

 Purification treatments of long duration are often 

 necessary. Since the cotton fiber is hollow, pulp- 

 ing is necessary to remove the last traces of acid, 

 while alcohol dehydration improves stability by 

 the solution of the lower nitrated, unstable types. 

 In the non-explosive arts the most common effects 

 of instability are .the formation of a brittle film, 

 discoloration of dyes and corrosion in metal lac- 

 quers. By the use of alkaline treatments foUowdng 

 an acid hydrolysis, better stability may be ob- 

 tained without impairing the appearance of the 

 nitrocellulose solution. 



' Certain aspects of the chemistry of cellulose 

 acetate from the colloidal viewpoint: G. J. Es- 

 SELEN. Considering cellulose as a colloidal aggre- 

 gate, certain of the changes involved in the prepa- 

 ration and use of cellulose acetate are considered 

 from the colloidal viewpoint. With these consid- 

 erations as a basis, a theory is offered to explain 

 a number of previously unconnected facts regard- 

 ing the solubility of cellulose acetate. 



Projects of the preliminary committee on Ameri- 

 can cotton research: H. E. Howi;. 



Is it advisable to form a section of cellulose 

 chemistry? Jasper E. Crane. 



The determination of cellulose in woods: L. F. 

 Hawlet. a uniform size of particle appears to 

 be essential if comparable results are to be ob- 

 tained in the determination of cellulose in woods. 

 Material which passes an 80-mesh standard sieve 

 but is retained on a 100-mesh sieve has been found 

 to be most satisfactory from the standpoint of 

 both yield and manipulation. Material obtained 

 by a single mechanical process of disintegration 

 may give a sample on sifting which is not repre- 

 sentative. To avoid this a combination of two 

 processes, sawing and grinding, has been used. 

 The apparatus recommended by Sieber and Walter 



