590 ANNUAL KErORTS OF THE DEPARTMENT OF AGRICULTURE. 



ENOLOGICAL CIIE^NriCAL RESEARCH. 



The woi-k of tliis section for the past year has been chiefly along 

 the follo-svino^ lines: 



(1) The contimiation of (he examination of ripe grapes to deter- 

 mine tlieir normal c()ni])o.sition. The samples were collected in New 

 York, Pennsylvania, Ohio, and Michigan in the northern grape belt 

 and Virginia in the southern, both from the vineyards and from tlie 

 factories wliicii make nnfermented juice and wines. Two hundred 

 samples of fruit were examined and 1.440 determinations were made, 



(2) The study of the composition of grapes for a period of several 

 weeks during ripening. For this work representative plants of the 

 more important varieties used for grape juice and wine, as Catawba, 

 Clinton, Concord, Cynthiana. Delaware, and Norton, were selected 

 and the fruit held intact for the purjjoses of this investigation. The 

 period of study covered about 12 weeks, 147 samples being examined, 

 comprising 3,381 determinations. The work on the above two lines, 

 coupled with the previous investigation on grapes, resulted in secur- 

 ing valuable data for use as a basis in detecting sophistication of the 

 food products made from grapes. 



(3) The study of the composition of apples has been continued 

 and is nearing completion. One hundred and ninety-two samples 

 were examined during the year, comprising 2,G58 determinations. 



(4) The study of the normal composition of pure wines made from 

 native grapes in this laboratory has received more attention than any 

 other subject during the year. Twelve additional samples were made 

 during the fall of 1911 from standard varieties used for vintage 

 purposes for a special study on the acid elements of the fruit, young 

 wine, and dry wine. The chemical work required 1,136 determina- 

 tions. Of the wines made in this laboratory in former years 79 

 samples have been held for critical study on the normal composition 

 both of the organic and inorganic elements, requiring 4,896 deter- 

 minations. It appears from this work that certain elements, espe- 

 cially in the composition of the ash, are so constant in amount as to 

 furnish very reliable data for the detection of fraudulent articles. 



(5) Thirty-nine samples of commercial wine and grape juices have 

 been analyzed for technical studies of their composition. The chem- 

 ical data comprise 1,014 determinations. 



(6) During the past three years much attention has been given to 

 detecting errors in methods for the analytical work necessary on the 

 samples handled in this laboratory. This has resulted in important 

 modifications of the methods now in use for determining tartaric 

 acid, cream of tartar, malic acid, and acid bound to alkaline earths. 



(7) The studies with yeast organisms for the year comprised incu- 

 bator studies to determine fermenting power at low temperature. 

 Three hundred and fifty-two determinations were made on 32 sam- 

 ples. 



MISCELLANEOUS INVESTIGATIONS. 

 WORK OF THE MISCELLANEOUS DIVISION. 



The miscollaneous division conducts the examinations of waters, 

 insecticides and fungicides, cattle foods, grains, trade wastes, and 

 hygienic and miscellaneous samples and research work along these 

 lines. 



