October 1, 1920] 



SCIENCE 



319 



THE AMERICAN CHEMICAL SOCIETY. 

 IX 



DYE SECTION 



Charles L. Reese, chairman 

 E. Norris Shreve, secretary 



Dye patents of the chemical foundation, incor- 

 porated: S. A. Tucker. The paper deals with the 

 classification of the dye patents owned by the 

 company which forms the largest division of any 

 class of its patents, and covers practically all 

 classes of dyes. The method followed enables one 

 to locate any patent either by the chemical con- 

 stitution of the dye or its application. Patents 

 actually licensed either by the Chemical Founda- 

 tion or the Federal Trade commission are dis- 

 cussed at considerable length. A list of patents 

 of which the Schultz number is known but which 

 have not yet been licensed is given. The advan- 

 tages in the form of license as issued by the 

 Chemical Foundation are pointed out and the in- 

 fluence which the company may have on the 

 American chemical industry is discussed. 



Dyes for photographic sensitizing: W. F. Meg- 

 gers and F. T. Stimson. Illustrations are given 

 of the photographic impression made by a con- 

 tinuous spectrum upon Seed's 23 plates before 

 and after treating with typical photo-sensitizing 

 dyes. Spectral transmission curves of the dye 

 solutions and spectral sensitivity curves of photo- 

 graphic plates stained with the dyes are shown. 

 Examples of the use of color sensitive photo- 

 graphic plates in aerial photography are exhib- 

 ited and the importance of photo-sensitizing dyes 

 to future developments in photography is empha- 

 sized. 



Anthranilic acid, tests and purity of the com- 

 mercial product: J. F. Eagsdale. The melting 

 point of anthranilic acid is found to be higher 

 than that usually given in the literature. Since 

 decomposition occurs on melting, certain precau- 

 tions must be observed in taking the melting 

 point. Various methods for determining the 

 anthranilic content of the commercial product are 

 discussed, and diazotation with standard nitrite so- 

 lution is recommended. Several methods for 

 standardizing the nitrite solution have been tried, 

 and advantages and disadvantages of each are 

 pointed out. 



1 Ortho chlor para toluene sodium sulfonate — 

 purity and tests of the commercial product: L. A. 

 Watt. Ortho chlor para toluene sulfonate is one 

 of the dyestuff intermediates now produced in 



quantity in this country. The impurities encoun- 

 tered in the commercial product are enumerated 

 and a procedure for their detection and determi- 

 nation based on the relative solubilities in alcohol 

 is suggested. Data obtained from the examina- 

 tion of both low grade and typical commercial' 

 products are given. 



Uses of formic and oxalic acids in the dyeing 

 industry: Lancelot W. Andrews. For the acidi- 

 fication of dye baths, an acid should be selected 

 having intrinsic strength enough to cause full 

 utilization of the dye and fixation on the textile, 

 but not having so great intrinsic strength as to 

 injure the fabric. The intrinsic strength of the 

 acids are determined by their electro-dissociation 

 coefficients. It is shown by both theory and prac- 

 tise that formic acid is particularly well suited for 

 use of the dyer and that its high dissociation con- 

 stant and its low molecular weight, render its em- 

 ployment thoroughly economical. Formic aeid 

 offers the following advantages as compared with 

 the mineral acids, or with acetic and other avail- 

 able organic acids: (1) No tendering of the tex- 

 tile, (2) greater evenness of dyeing, (3) better 

 exhaustion of the dye, (4) better fixation on the 

 textile, (5) brighter color, (6) better penetration, 

 (7) economy. American manufacturers are now 

 able to supply both formic and oxalic acids, and 

 the mordant salts of these acids, with Al, Cr, Sn, 

 Sb, etc. 



Synthetic dyes as applied to chemico-therapy and 

 microscopy: Geo. Hetl. Part 1. Medicinal Dye- 

 stuffs: (A) Theory of action. (B) Synthesis and 

 pharmacological effect. (C) Classification of med- 

 ical dyestuffs: (a) Eutherapeutic and dy thera- 

 peutics; (6) Dyestuff specifics (salvarsan, acri- 

 flavine, etc.); (c) External dyestuff antiseptic; 

 (d) Dytherapeutics and parasitioidal action; Try- 

 pan blue, trypan red, naga red, methylene blue, 

 etc.; (e) Neutral dyes and nerve cells; Methy- 

 lene azur, eosine-azurs, etc., and neutral red. 

 (D) General outline of preparation. Part 2. 

 Microscopic Staias: (A) Theory of action (Ehr- 

 lich-Witt). (B) Classification. (C) Standardiza- 

 tion. 



Dye research: Egbert E. Eose. Eesearch we 

 must have — not a mere checking up of receipts, 

 not a mere search for information which is known 

 to others. We must graduate to real research, 

 that is, enter the entirely unknown. Much of this 

 type of research must be done in the universities, 

 but under conditions of close cooperation with the 



