358
T H E J O U R N A L OF I N D U S T R I A L A N D ENGINEERING C H E M I S T R Y
22-Whitney and Ober: J . A m . Chcm. Soc., 28 (1901), 856-863. Gives an excellent bibliography, with brief comment, of colloid work published before 1901. Nearly 150 references. 23-A. Muller: “Bibliography of Colloid Chemistry,” Z. anorg. Chem., 89 (19041, 121. 356 references grouped by subjects, without comment 24-Hober : “Physikalische Chemie der Zelle und Gewebe.” Wilhelm Engelmann, Leipzig, 1911. 25-Rideal and Taylor: “Catalysis in Theory and Practice.” The hfacmillan Co., New York, 1919. Not primarily a colloid book but contains material of value t o colloid chemists. A new edition is promised. Kollozd-Zeitschrifi and its Bcibefte have devoted their columns exclusively to colloid research. Very important.
The Journal of Physical Chemistry contains a vast amount of invaluable material and no student of colloid chemistry can afford to neglect this journal. Many of the articles contain exceptionally full summaries of the work done in special fields, and are really monographs. The results of colloid research, however, are found in most of the great journals. Since many chemists waste time and become discouraged by reading the wrong book first, we urge any one of the first three in the above list as the proper introduction to the subject. HARRYN. HOLMES,Chairman, OBERLIN, OHIO OBGRLINCOLLEGE Committee on Chemistry of Colloids
Vol. 13, No. 4
Calendar of Meetings Technical Association of the Pulp and Paper IndustrySpring Meeting, Waldorf-Astoria and Hotel Astor, New York, N. Y., April 11 to 14, 1921. American Paper and Pulp Association-Annual Meeting, Waldorf-Astoria and Hotel Astor, New York, N. Y., April 11 to 15, 1921. American Electrochemical Society4pring Meeting, Hotel Chalfonte, Atlantic City, N. J,, April 21 to 23, 1921. American Chemical Society-Sixty-first Meeting, Rochester, N. Y., April 26 to 29, 1921. American Oil Chemists’ Society-Twelfth Chicago, Ill., May 16 to 17, 1921.
Annual Meeting,
American Institute of Chemical Engineers-Spring Detroit, Mich., June 20 to 21, 1921.
Meeting,
Seventh National Exposition of Chemical Industries-Eighth Coast Artillery Armory, New York, N. Y., September 12 to 17, 1921.
NOTES AND CORRESPONDENCE Note on the Use of Potassium Permanganate in the Determination of Nitrogen by the Kjeldahl Method Editor of the Journal of Industrial and Engineering Chemistry: It was for a long time the practice in this laboratory to add potassium permanganate a t the end of digestion in the determination of nitrogen. About a year ago i t was decided to determine whether the addition of the permanganate was necessary. After making determinations for several weeks in which permanganate was added to one of the duplicates, we concluded that it had no effect and its use was discontinued. On that account we were surprised a t the results obtained by Cochrane [THIS JOURNAL, 12 (1920), 11951. The results of further experiments lead to the conclusion that the addition of permanganate is not necessary when sodium or potassium sulfate and mercury are used with the sulfuric acid in the digestion. It was noted that Cochrane did not use either potassium or sodium sulfate and i t seemed possible that the more uniform results obtained when he used potassium permanganate were due to the fact that the digestions were not complete a t the end of 2 . 5 hrs. Several digestions were, therefore, made with sodium sulfate in one duplicate and none in the other. The results showed that the digestion is not complete within 2 . 5 hrs. if the sulfate is not added. Our results are summarize:d in the following table: -Per cent c)f Nitrogen4 2 3 NazS04 NanSOi and no and No KMnOi KMnOa KMnOa KMnOd Added Added Added Added Average Average Average Average 7.043 6.822 7.043 6.993 7.043 6.789 7.044 6.977 2.730 2,784 2.712 2.720 2.461 2.444 1.488 2.470 1.400 1.344 I . 394 1.342 1.400 1.300 1.283 1.360 0,499 0.459 0.492 0.472 0.483 0.424 0.486 0.464 r
1
No. of Dqter minaSUBSTANCE tions Cottonseed Meal A ,, 2 Cottonseed Meal B . , 2 Wheat Mixed Feed A . .2 Wheat Mixed Feed L Sc. A 2 Comp. Feces A . . 2 Comp. Feces B . . , .. 2 Broom Corn Silage Refuse A 2 Broom Corn Silage Refuse B 2
...... ..... .... . .... ........... . .
C. T.DOWELLAND
samples analyzed, the data presented in Columns 1 and 2 of the table support the conclusions drawn in my article. No comparison was made in my article between the straight Kjeldahl method and the Gunning modification, nor were any data presented bearing on the use or non-use of permanganate in any method where sodium or potassium sulfate is used to raise the boiling point of the digestate. D. C. COCHRANE PENNSYLVANIA STATECOLLEGE STATECOLLEGE, PA. February 5, 1921
The Formation of Anthracene from Ethylene and B,enzene-Correction I n our paper on the above subject [THISJOURNAL, I3 (1921), 2081 several self-evident errors escaped proof reading, and we wish to have them corrected though they do not in any way affect our results or conclusions. On page 208, first column, the reaction should read: H
,..
H
On the same page, second column, the reaction should read: C2H4 + CI~HIO 3H.2 - 5.2 Cal.
+
+
On the same page, second column, footnote,the change should be 2C6 2H6 + 2CeH6 - 22.6 Cal. and CMHW instead of CIOHI~. J . E. ZANETTIAND M. KANDEL
+
COLUMBIA UNIVERSITY NEW YORK,N . Y.
The Estimation of Cellulose in Wood
Editor of the Jourllal of Industrial and Engineering Chemistry: W. G. FRIEDEMANN
OKLAHOMA AGRICULTURAL EXPERIMENT STATION STILLWATER, OKLAHOMA January 20, 1921
..........
Editor of the Journal of Xndustrial and Engineering Chemistry: I would call attention to the fact that in five out of the eight
With the exception of a few attempts to determine the cellulose content of lignified materials by dissolving and reprecipitating the cellulose, i t has been the object of all quantitative cellulose determinations to isolate the cellulose by dissolving out the noncellulose compounds. A complete removal of these compounds from a highly lignified substance, such as wood, without
