BUBEAU OF CHEMISTRY. 483 



gations looking to the improvement of the quality of rosin are being 

 conducted, but are not sufficiently advanced to warrant conclusions. 



The quality or grade of rosin is determined by its color and free- 

 dom from foreign materials, and is established by comparison with 

 standard type samples. ^luch dissatisfaction now exists owing to 

 the changes which occur in these types, and the laboratory is investi- 

 gating tiie feasibility of preparing permanent rosin type standards 

 with which the types used in the actual grading may be compared 

 from time to time to assure their accuracy. 



Leather. — The research work on sole leather had for its primary 

 purpose the improvement of the quality of the product and the devis- 

 ing of tests for its examination. In this work the cooperation of 

 several large manufacturers of shoes has been secured, such manu- 

 facturers in general being much interested in preventing the adul- 

 teration of leather with materials which are useless or harmful. The 

 work so far done indicates that much, if not the larger part, of the 

 sole leather now on the market has been heavily loaded with glucose, 

 Epsom salts, barium sulphate, etc., or with two or more of such mate- 

 rials. This practice from the point of view, both of the consumer and 

 of the manufacturer of shoes, is utterly without excuse, as the quality 

 and wear of the leather are certainly materially reduced thereby, 

 while its cost is increased. In these days, when the quantity of tan- 

 ning materials and hides available is barely sufficient to meet the 

 demand, every effort should be made to conserve them through the 

 manufacture of leather of the highest quality and greatest durability. 

 The work on leather has progressed sufficiently to justify the con- 

 clusion that vigorous steps should be taken to prevent the adultera- 

 tion or loading of leather in any way. 



Miscellaneous work. — Miscellaneous samples, including fertiliz- 

 ers, wastes, oils, and various industrial materials, have been examined 

 at the request of other departments and of other bureaus of this 

 Department, and the laboratory has cooperated with chemical associ- 

 ations in the study of methods for the examination of leather and 

 tanning materials, in the preparation of specifications for suitable 

 and permanent paper for scientific publications, and in the study of 

 methods for the estimation of iron and alumina in phosphate rock. 

 The work of the Leather and Paper Laboratory is in charge of 

 F. P. Veitch. 



examination of contract supplies. 



The constant demand for the testing of current supplies by the 

 various governmental branches, accompanied generally by the request 

 that the work be rushed as rapidly as possible, leaves little or no 

 time for systematic research. Considerable work has been done in 

 the revision of existing sjiecifications for miscellaneous supplies and 

 the preparation of definite specifications where formerly none was 

 used. A large number was prepared for the General Supply Com- 

 mittee and for the Commissioners of the District of Columbia, with 

 the result that (he number of samples tested was diminished very 

 much as compared with preceding years by letting the contracts on 

 the bases thus establislu d and thus rendering sampling on competitive 

 bids unnecessary in many cases. Some progress has been made also 



