BUREAU OF CHEMISTRY. 215 



Mothods have been devised for chlorinating, sulphonating, and 

 nitrating c,ymene, and numerous useful compounds and dyes have 

 been prepared from it. Cymene is a h^^drocarbon obtained as a by- 

 product from the sulphite-spruce paper industry. Two million gal- 

 lons per annum are estimated to be available. No commercial use is 

 now made of it. A paper on the nitration of paracymene has been 

 published. 



New methods for refining anthracene pressed cake have been de- 

 vised, and processes for obtaining pure anthracene, phenanthrene, 

 and carbazol are in an advanced stage of development. Improve- 

 ments have been made in the methods for purifying anthraquinone. 

 Inasmuch as these projects required that vapor pressure measure- 

 ments upon a large number of compounds be made, a new dynamic 

 method for measuring vapor pressures was developed. 



A large number of dyes necessary for the sensitizing of gela- 

 tin emulsions of silver halids required in photography are being 

 prepared and studied in cooperation with the Bureau of Aircraft 

 Pi'oduction and the Bureau of Standards. The production of a 

 large number of quinolines used in the synthesis of these sensitizing 

 dyes is in progress. 



A number of dyes useful in biological research are being pre- 

 pared and studied. Among them are included known and new sul- 

 phophthaleins for the measurement of the hydrogen-ion concentra- 

 tion of solutions and vital red required in considerable quantities by 

 the Surgeon General for certain blood studies. 



A compilation of the literature of all American patents on dyes is 

 in an advanced stage of preparation. 



Five patents based on work of the Color Laboratory have been 

 allowed and a number of others are pending. 



NAVAL STORES. 



Data on the extent of adulteration of turpentine and misgrading 

 of rosin for the last three years have been compiled. Information on 

 the commercial weighing of naval stores has been gathered. Observa- 

 tions which indicate that adhesives containing rosin in combination 

 with various oils can be used satisfactorily in the manufacture of 

 fiber and wall board requiring special waterproof properties have 

 been made. Glass rosin type samples have been deposited with 

 the Chamber of Commerce, Pensacola, Fla., and with the United 

 States Food and Drug Inspection Station, Boston, Mass. The British 

 Government Inspection Bureau has been assisted in purchasing rosin. 



The description of a simple colorimeter for determining the color 

 grade of turpentine has been published. A satisfactory process of 

 refining wood turpentine applicable to the commercial plant has been 

 developed. 



LEATHER, TANNING, AND FINISHING MATERIALS. 



Data on the wear resistance of leather from different parts of the 

 hide have been published, and a report on a mechanical wearing test 

 of shoc-soling materials is in press. The description of a volumenom- 

 eter specially designed in this connection has been printed. A bul- 

 letin on domestic sumac, giving detailed directions for the proper 

 gathering and curing of sumac, has been published, 



