77 
TAPPING INTEEVALS. 
''The yield from a given tree appears to increase for the 
first six to twelve tappings, after which it decreases some- 
what till a point is reached where it remains about constant. 
The word 'tapping' includes the pricking too. Hence, a se- 
ries of six, nine or twelve tappings may well be followed by 
a rest. For instance, if the yield diminishes after six tap- 
pings, it might be well to rest it. Probably twelve tappings 
should be made. We have found that a rest of a week is 
sufficient at some periods. In this way we remove all the 
bark we can. If we start from the tree, our next two parings 
will remove that portion, and then the next time we take off 
some more bark, when pricking comes immediately after 
the removal of the bark. This pricking takes place as soon 
as the bark is removed. 
'Tf a third of an inch is removed at each paring, then in three 
parings, or nine tappings, one inch of bark will have been re- 
moved, and there is plenty of authority for advocating a rest 
at this stage. We have found that a rest of a week or ten 
days is sufficient, and then we start again and get about the 
same result. At this rate, also, fifty-four tappings will take 
off all the bark between adjacent cuts. Therefore, tapping 
for one week and resting for three weeks would remove all 
the bark on one side of the tree in about six months, when it 
must be rested before beginning on the other side. 
"The more rubber we get from each tree at each tapping, 
the more economical the tapping. After the bark on one 
side of the tree has been removed for tapping, after six 
months' rest we would go around to the other side of the 
tree. It has been found by the experiment station reports 
and observations that if the tapping is carefully done and not 
too deeply, it will renew in less than a year. It is only in 
certain points and when the pricking is too deep, that swell- 
ings on the wood are caused. If the pricking is carefully 
done, it does not swell, but the pricking does go into the most 
prolific cells, while in order to get in there with the knife we 
would have to cut deep, because the bark is so thin. Thus 
far we have not found satisfactory knives. 
ALTERNATE TAPPINGS. 
"A movement is on foot, and growing, in the Far East, to 
limit tapping operations in any one year to a quarter or a 
third of the tree, instead of to a half, as heretofore, thus giv- 
ing three years instead of two for the tapping surface to be 
renewed. This might well be considered by us, in which case, 
instead of the full herringbone, going half around the 
tree, the half herringbone going one third around, might 
