BUEEAU OF CHEMISTRY. 463 



samples of wines from native g^fapes and three samples of ciders were 

 made for the purpose of studjdng the chemical composition and 

 quality of these products. 



Eighty samples of wines and 25 samples of ciders manufactured 

 by tliis laboratory are now undergoing chemical study for the deter- 

 mination of technical questions as to their normal composition and 

 the changes wliich occur in the important constituents of these 

 products during maturity. The chemical work under this head 

 comprised 2,728 determinations at the Stonehenge laborator}^ the 

 past year. Tliis study is made as exhaustive as the facilities permit, 

 and promises when completed to furnish important data as to the 

 normal constituents of natural wines. Sophisticated wines were also 

 made and studied in like manner. The chemical work on ciders 

 required 480 determinations, and has been so far completed that 

 the fundamental facts are fairly well established, but the work on 

 wines will require further investigation. 



Of the commercial wines 133 samples were examined at the Stone- 

 henge laboratory, requiring 2,392 determinations. These were wines 

 made from native American grapes and the data are very important 

 for comparison with the results on the experimental wines. 



Sixty grape samples and 28 apple samples were analyzed at the 

 main laboratory, necessitating 936 determinations. At the Sandusky 

 laboratory 583 samples of grapes and by-products from grapes, such 

 as pomace, etc., were handled, 4,664 determinations being made^ 

 and 498 samples of apple products were analyzed, necessitating 5,478 

 determinations. 



The total number of determinations made during the year at 

 Stonehenge laboratory was 6,536 and at the Sandusky laboratory 

 10,142. 



During the past year the results on a study of the occurrence of 

 sucrose in native Ajnerican grapes and on the development of acid 

 and sugar in native grapes during ripening has been published (Bul- 

 letin 140), and a report on the chemical composition of American 

 grapes has been compiled. The latter contains the analyses of 100 

 samples of the leading varieties of American grapes made during 

 the season of 1908; 396 samples analyzed in 1909, and 511 samples 

 analyzed in 1910. The samples include practically all of the varie- 

 ties grown in the Eastern and Central States, and in the case of the 

 best varieties numerous samples were collected from the more im- 

 portant fruit districts mentioned. The completion of this work will 

 oring together a large amount of data wliicn has not heretofore been 

 available. 



INVESTIGATIONS OF THE LEATHER AND PAPER LABORATORY. 



LEATHER. 



In the research work on leather approximately 100 samples of sole 

 leather have been examined. The results of these examinations, so far 

 as they relate to composition, have been compiled. Approximately 

 58 per cent of the leathers examined are weighted with glucose, 

 Epsom salts, or both. The weighting contains from 1 to 7.5 per cent 



