SUGAR AND ACID IN GRAPES DURING RIPENING. 5 



lying limestone. The land is flat and only a few hundred yards from 

 the shore of Lake Erie. The 1911 samples of Clinton were taken from 

 a neighboring vineyard on similar soil. These samples were collected 

 in every instance by J. R. Eoff. who was in charge of the chemical 

 examinations at Sandusky. 



The 1911 samples of Concord, Delaware, and Norton at Char- 

 lottesville, Va., were taken from a vineyard of which the soil is the 

 characteristic Piedmont red clay, lying on a slope just below an 

 outcrop of gray sandstone. The Cynthiana samples were taken from 

 another vineyard situated on soil of like character. These samples 

 were taken in every instance by William B. Alwood or B. G. 

 Hartmann. 



During 1912 fewer varieties were examined than previously, but 

 the amount of work done was extended to cover points not before 

 investigated. At Sandusky only Concord and Catawba were ex- 

 amined, and these were obtained from the vineyard first described. 

 At Charlottesville, Concord and Delaware were examined, both from 

 the vineyard which had supplied samples of these varieties the pre- 

 vious year. 



For all examinations of whatever nature about 5 pounds of fruit 

 were selected in the vineyard and the bunches were placed in a small 

 fruit basket and stored uncovered in the cellar of the laboratory for 

 18 to 24 hours at a temperature of about 60° F. The purpose of 

 holding the fruit in the cellar was to bring all samples to as nearly 

 as possible the same temperature before crushing, so that the results 

 for cream of tartar should not be affected by reason of the variation 

 in its solubility at different temperatures. 



The fruit used for juice samples was brought from the cellar and 

 crushed at once by hand in porcelain-lined vessels. About 2 pounds 

 of unstemmed fruit were used and care was observed to take aver- 

 age quality as to ripeness. The berries were carefully pulped with 

 the fingers until well broken up, then the juice was expressed through 

 a double thickness of cheesecloth, working the pulp into a ball in 

 the cloth and applying such pressure as experience has shown will 

 ordinarily extract the juice as efficiently as when freshly pulped 

 fruit is pressed on a power press at 1,500 pounds direct pressure. 

 The juice recovered was strained by filtering through -cotton, and 

 from this portion the chemical sample was taken. A Brix reading 

 was then made at 20° C. on the fresh juice. Then 250 cc of the 

 sample, the quantity desired for analysis, were measured and diluted 

 with an equal volume of distilled water, thus giving 500 cc. This 

 diluted sample was filtered through paper and a 20 cc portion titrated 

 for total acid; the specific gravity was determined at once in a 

 pycnometer. During 1912 the specific-gravity determinations were 

 made in a pycnometer on the undiluted juice. The further determi- 



