survived those qualities to which was owing its former fame; 
the cider that has been made with it alone, within the last 
thirty years, having rarely proved good: but in mixture with 
other varieties it communicates its fine flavour; and in some 
instances a cask of genuine Redstreak Cider has been found to 
deserve all the commendations, which our ancestors gave it. 
I found the specific gravity of the juice of the Redstreak, 
when recently expressed from a selected sample of the fruit, 
to be 1079j after the pulp had been thoroughly reduced, and 
exposed during twenty minutes to the air.* 
^ During the grinding of apples for cider^ I have discovered that much air 
(probably pure oxygen) is absorbed; and during this absorption much sac¬ 
charine matter is apparently generated ; for the juice of very harsh and acid 
apples becomes rich and sweet, and acquires many degrees of specific gravity. 
In estimating the specific gravity of the recently expressed juice of those varie¬ 
ties of the apple and pear, which will be delineated in the succeeding pages, 
the fruit of each variety was selected as nearly as possible at the same degree 
of maturity, being ripe, but not mellow, and the process of preparing it was, 
in all cases, the same. 
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