AGRICULTURAL. CHEMISTRY — AGROTECHNY. 505 



those obtained in 1910 showed that " the total sugar content in the fresh fruit 

 varied about 3 per cent in the first year and about 5 per cent in the second 

 year. The ratio of reducing sugar to sucrose content varied from 1 : 0.80 to 

 1 : 1.04 in 1909 and from 1 : 1 to 1 : 1.19 in 1910, thus showing a fairly constant 

 proportion between these two forms of sugar. The total acid content decreased 

 about one-third in each year during the period the variety was under exami- 

 nation." 



Some further work conducted duriug 1909 and 1910 in regard to the sugar 

 and acid content of the grape, sampled at different intervals during ripening 

 and at full maturity, are also reported. During 1900 the grapes examined were 

 of the Catawba, Montefiore, and Norton varieties, and the seedling noted above. 

 For the Catawba grapes it was noted that an increase in sugar and a decrease 

 in acid took place. " The Montefiore grapes showed an insignificant, loss of 

 sugar for the period as a whole and a very appreciable loss of acid. In the 

 case of the Norton the sugar remained practically the same, but the acid was 

 greatly decreased. . . . The seedling showed a decided gain in sugar and an 

 important loss in acid, considering the entire period, but there was a phenome- 

 nal gain in sugar during the second period and an equal loss during the next 

 one. This must be credited to the uneven growth and ripening of this seedling, 

 normal samples being hard to obtain during the fall of 1909." 



During 1910 the varieties Brighton, Catawba, Clinton, Concord, Delaware, 

 Ives, Norton, Pocklington, and Worden, and the seedling were examined. The 

 period for sampling in this investigation was much longer than that of 1909. 



" For Catawba the total sugar does not in any sample reach the average of 

 the general crop of that section, but the acid is about at the minimum for this 

 variety on the date when the last sample was taken. At that time the sugar 

 had apparently decreased, but the difference was too slight to be considered, 

 in view of the difficulty of taking two samples of grapes from the same lot 

 which do not show similar differences in composition. This variety in 1910 

 was high in sugar wherever the growth conditions were good. The fruit as 

 sampled more than doubled in sugar after the berries began to color and lost 

 more than half of the acid content shown in the first sample. The very decided 

 loss of acid even for the last 7 days, amounting to 0.4S1 per cent, is most im- 

 portant, although the sugar increased only 1.16 per cent. The ratio of increase 

 of sugar to loss of acid is very low for this variety. The observations with this 

 variety were not continued long enough to be conclusive, according to the 

 author. 



" Clinton was sampled for a longer period than any other variety, . . . The 

 analyses show that there was some increase of sugar up to the last sample, 

 loss of acid is not so important as for Catawba, but the gain in sugar in pro- 

 portion to the loss of acid is greater. 



" The Concord samples were in remarkably good condition at the last analy- 

 ses. While neither the gain of sugar nor the loss of acid is remarkable in total 

 amount, yet the results show a great improvement in the fruit as sampled for 

 this study as compared with the samples harvested for the vintage. . . . The 

 proportional increase of sugar to loss of acid for this variety is above that of 

 any of the strictly wine grapes. 



" The data for Delaware show that . . . the rise in sugar during the 26-day 

 period when this variety was sampled was not so great in proportion to the 

 total as was found in the Catawba, Clinton, or Norton, but the drop of over 

 one-half in total acid is of the greatest significance, and the proportional 

 increase of sugar to acid lost is greater than in the other varieties of strictly 

 wine grapes mentioned. 



