BUREAU OF CHEMISTRY. 471 



Four hundred and twenty-one interstate samples taken by the 

 inspectors in the reguLar way Avere examined at the hiboratory during 

 the past year, 297, or 70 per cent, of Avhich were found to be in viola- 

 tion of the law. Of these samples G8 were coffee, of which 55, or 80 

 per cent, were illef^al, a majority being falsely represented to be 

 Mocha and Java mixtures. A marked improvement in the labeling 

 of coffee in this respect has been noted since the inspection of this 

 product was commenced. 



One hundred and thirteen samples of vinegar were analyzed, 67 

 per cent of which were found to be adulterated, the chief form of 

 sophistication being the substitution of mixtures of distilled vinegar 

 and boiled cider for the true cider vinegar. 



Aside from the imported and interstate samples analyzed, there 

 have been received from the Panama Railroad Company, the Isthmian 

 Canal Commission (medical supply depot), the War Department, the 

 Navy Department, and the Department of Commerce and Labor 

 about 250 samples of food products and medicines for examination 

 as to purity and conformity with the specifications. 



Twenty-four samples of food products were also received for anal- 

 ysis for certification for the export trade, certification being granted 

 in all but 5 instances. The remaining 19 samples covered 56 lots, 

 and 56 certificates were issued. 



This laborator}^ has also passed upon 189 samples of denaturants 

 for olive oil. By the provisions of the present tariff act and the regu- 

 lations of the Treasury Department, olive oil intended for technical 

 use only may be permitted into this country free of duty if denatured 

 in such a manner as to be unfit for food purposes. The kind of de- 

 nalurant and its fitness for the purpose intended is passed upon by 

 the Department of Agriculture. Thus far the following denaturants 

 have been permitted : Oil of rosemary, oleoresin of capsicum, oleic 

 acid, wood turpentine, pyridin, creosote, and anilin oil. Application 

 for denaturing is accompanied with the material it is proposed to use, 

 which material is sampled by this laboratory and its suitability for 

 the purpose determined. 



Inatistigations. — An investigation of the subject of cider vinegar 

 was begun, the principal factories of the eastern part of the country 

 being visited and the processes of manufacture studied. Samples of 

 raw materials and of the product at the various stages of manufac- 

 ture were obtained and analyzed. A representative of the laboratory 

 was stationed for some time in one of the factories to study the 

 chemical changes that occur in the product during the daily opera- 

 tion. The work as far as completed promises to be of much value, 

 and it is expected to continue the investigation during the coming 

 season. 



The routine and investigation work on the subject of coal-tar col- 

 ors for use in food products has been continued during the past year, 

 the entire time of one chemist and a portion of that of two others 

 having l)een occupied with this work. Sixty samples have been ex- 

 amined, of which about 95 per cent were rejiorted as complying with 

 the Department's requirements for certification. The studies of 

 methods for analysis of colors have been continued, and the follow- 

 ing have been devised : (1) A method for estimation of iodin in inor- 

 ganic compounds with special reference to mixtures containing halo- 



