22 
BULLETIN 229, U. S. DEPARTMENT OF AGRICULTURE. 
of gum, since clay does not become heated like metal when exposed 
to the sun and thus cause evaporation of the turpentine. Clay cups 
are three or four times as heavy as metal cups, however, and much 
more bulky. They are also more likely to break, both in transit and 
in handling. On the other hand, they do not rust like the galvan- 
ized-iron cups. Rusting not only results in loss of cups, but may 
also darken the gum. 
In shape the cups may be like a flowerpot (Plate I, fig. 2), an 
oblong box (Plate V, fig. 1), or a flattened cone (Plate VII, fig. 2). 
With the deep cups, it is claimed, there is less evaporation of gum, on 
account of the smaller surface exposed. On the other hand, deep 
cups take up more vertical height on the tree, and are generally con- 
sidered more difficult to dip. The cone-shaped cups are similar in 
shape to the interior of the ordinary "box," being so made for the 
sake of economy, since only one seam is necessary. 
Within certain limitations the kind of cup used with a particular 
gutter or apron is immaterial. Between the cups and gutters now 
on the market, the greatest room for improvement exists in the case 
of the latter, though improved aprons and gutters are constantly 
put on the market. 
RELATIVE YIELDS SECURED FROM CUPS AND BOXES. 
Experiments made by the Forest Service in Georgia during 1902 
showed conclusively that more and better turpentine and rosin can 
be obtained by the use of cups than by the use of boxes. 
The timber studied consisted of a first, second, third, and fourth 
year crop, one-half of each crop being turpentined by the cup sys- 
tem and the other half by the box system. The comparative results 
are shown in Tables 9 and 10. 
Table 9. — Spirits of turpentine from eight half crops, season of 1902, Georgia. 
Half crops. 
From 
dip. 
From 
scrape. 
Total. 
Excess from cup- 
ped trees. 
First year: 
Cups 
Boxes . . . 
Second year: 
Cups 
Boxes . . . 
Third year: 
Cups 
Boxes . . . 
Fourth year: 
Cups 
Boxes . . . 
Gallons. 
1,385.3 
1,134.7 
1,087.2 
941.8 
726.5 
381.9 
687.2 
349.5 
Gallons. 
205 
153.7 
188.2 
267 
113 
147.5 
101 
124.5 
Gallons. 
1,590.3 
1,288.4 
1.275.4 
1,208.8 
839.5 
529.4 
288.2 
474 
Gallons. 
301.9 
310.1 
314.2 
Per cent. 
23.43 
5.51 
58.58 
