NOLOGICAL STUDIES. 21 



DISCUSSION OF ANALYTICAL DATA. 



It is manifestly misleading to compare data on the ripening of 

 grapes by the calendar days, rather than by periods covering com- 

 parative conditions of ripening. But whatever may be done along 

 tho line of such a comparison is necessarily arbitrary and largely a 

 matter of personal opinion. In the following comments no compari- 

 son of each variety with the others is intended; the purpose of the 

 discussion is rather to call attention to the salient features in each 

 case. Comparisons of technical importance must await the accumu- 

 lation of much data covering a series of years, and even then those of 

 the most value will in the writer's estimation be the comparisons 

 made between the data on a given variety. Such data as are here 

 presented, when sufficiently extended, may reasonably be expected 

 to indicate important details in methods of harvesting the several 

 varieties. 



The results for Brighton have very little significance and indicate 

 that the crop had passed its maximum condition before the last sam- 

 ple was taken. In this case the sampling should have begun 10 days 

 sooner. 



For Catawba the total sugar does not in any sample reach the aver- 

 age 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 

 is 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 differ- 

 ences in composition. This variety in 1910 was high in sugar wher- 

 ever 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 seven days, amounting to 0.481 

 per cent, is most important, 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. 



Clinton w T as sampled for a longer period than any o N ther variety. 

 It is well known to students of grapes that though this variety colors 

 early, it hangs well and should be permitted to remain on the vines 

 as long as possible. Yet the custom of the Lake Erie district is to 

 harvest this variety before Catawba. The analyses show that there 

 was some increase of sugar up to the last sample, but the acid re- 

 mained constant after October 3. The actual gain in sugar and loss 

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

 proportion to the loss of acid is greater. 



The Concord samples were in remarkably good condition at the 

 last analysis. This variety is invariably harvested before it is ripe in 

 the Sandusky district. While neither the gain of sugar nor the loss 



