REPORT OF THE CHEMIST. 199 



papers. An instrument has been constructed for the measurement of 

 the translucency of paper. Instructions for testing the folding 

 endurance tester, with data on the accuracy of this machine, have 

 been prepared for publication. Papers have been published upon a 

 new colorimeter and upon the detection of faulty sizing in high- 

 grade papers. 



" Tanning. — A manuscript has been prepared upon American sumac 

 to aid the farmer in gathering this plant and to help supply the de- 

 mand in the dyeing and tanning industry. It has been found that 

 the best way to denature egg yolk for tanning is to add 2 per cent of 

 birch tar oil. Power distillate may also be used. 



Naval stores. — The Board of Trade of Brunswick, Ga., adopted the 

 glass standards of the rosin types. They are now practically univer- 

 sally recognized in the Union. Examination of samples of rosin, mostly 

 the pale grades, representing nearly 6,000 barrels, showed 9 per cent 

 to have been graded too low and 38 per cent too high. A method for 

 denning and determining the grades of turpentine has been per- 

 fected. A rough survey was made east of the Mississippi to deter- 

 mine the extent of the adulteration of spirits of turpentine sold for 

 technical purposes. Twenty-six per cent of the samples were found 

 to be adulterated with mineral oil to the extent of from 3 to 100 per 



cent. 



DEMONSTRATION. 



In connection with its research and regulatory work the bureau 

 has done much demonstration and educational work. This has dur- 

 ing the past years grown to such an extent that it deserves separate 

 notice. Some of it has already been mentioned, as, for example, that 

 in connection with the canning of sardines, the manufacture of dried 

 and frozen eggs, the refrigeration of perishables, the shipping of 

 fresh shrimp, and of fresh fish. The work of the poultry and egg 

 packing demonstration car has increased greatly in efficiency and 

 results. During the year 101 towns in the State of Indiana were 

 visited and 10,600 people came to the car. 



An extensive demonstration campaign has been conducted on the 

 proper methods of packing tomato products which supplements the 

 effect of prosecutions in eliminating unfit products from the market. 

 In cooperation with the States Relations Service assistance has been 

 given to canning clubs, especially in Florida, in the preparation of 

 jams, jellies, and preserves. Assistance has also been given to manu- 

 facturers of these products. Instruction has been given in the grad- 

 ing of naval stores. Unfortunately a sufficient number of glass 

 standards is not yet available because the disturbed trade conditions 

 make it impossible to secure the necessary glasses. The demonstra- 

 tion of improved methods of producing rosin and turpentine has 

 been begun in a small way. It is soon to be made more extensive. 



ENFORCEMENT OF FOOD AND DRUGS ACT. 



Domestic foods and drugs. — Five hundred and seventy-seven rec- 

 ommendations for seizure and 787 recommendations- for criminal 

 prosecution were made through the office of the Solicitor to the De- 



