+ au pains years ey eontinte their extension in an upward direction. 
Be ccsseany the gum has. to cover an ever- -increasing length of way, in which process 
it gets more and more encrusted. _ In the course of time more and more scrape is 
obtained, ‘and an ever-decreasing amount of gum. Working the trees for turpentine 
a should be done during the last five years before their being cut down. 
It is said that with the pine tree a deterioration of the wood through rot is not 
-: to be feared, as has Ee. observed in fir trees as a result of the stoppage of resin 
exploitation. ; . 
In the course of the Chorin: experiments thé cost of producing one kilo of resin 
was calculated at KM 2.70, a figure which is considerably higher than it would be in 
a regular exploitation. 
os 
| Speornits of a much better exploitation of the turpentine oil contained in the gum, is 
An entirely different method of obtaining turpentine, which at the same time 
- recommended by H. Wislicenus'). He is of opinion that: the method practiced so far 
~ of obtaining gum in our pine forests must be looked upon as very imperfect; for the 
pine carries in its wood gum containing about 35 per cent. of turpentine oil of which 
= — as a rule little more than- one third is recovered under the system now in vogue. 
From an original pine resin Wislicenus obtained as much as 36 -to 38 per cent. of 
turpentine oil whereas in a fresh flow of resin after an hour, ¢.e. after a day, only a 
little over 26 per cent. was found and in resin collected after it had been left in the 
open cups for a few days, but 14 or 15 per cent. (and even less) was contained. Old 
fir scrape yielded but 3 per cent. of oil upon being distilled. Besides, the resin. 
obtained from the open “Lachten” and cups is invariably mixed with pieces of bark, 
needles, dirt, insects, &e. &e., amounting | to as much at 2 per cent. and more, and 
necessitating a costly process of purification. 
In Austria. considerable improvements, after the American prototype of Gilmer’s 
process (which is practically not suitable as yet). were worked out, by Kubelka?) and 
Schmoll who also put them to the test in a purely practical manner, but the difficulties 
attached to the procuring of the implements required absolutely prevent the general 
adoption and the economical value of the process, at any rate for the production of 
turpentine from the common pine. : 
As in the process_recommended by Kubelka, Wislicenus suggests that in a | place 
where the bark is thick, a hole be drilled, about 21/2 to 3 cm. in diameter, and reaching 
‘right through the ‘sapwood into the first layers of the heart-wood and — according tors 
 Kubelka — from this aperture two resin ducts should be made with a spiral drill’). 
_ According to Wislicenus these resin ducts may be just as well drilled tangentially 
Pe the outside which is more easily done, at least with the first drillings low down 
on the trunk, and has, moreover, the advantage of enabling the ducts being kept 
open from the outside without removing the collecting vessel, and to continue the 
_ toppings spirally around the circumference of the trunk. The last two duct drillings are 
carefully closed with a well fitting cork whereas the neck of a beer or wine bottle is 
_ introduced into the first ducts. The bottles keep well in their places from the first 
but after a day or so they are kept tighter still in quite a startling way by the growth 
- of the incised bark and trunk, and are fitted in air-tight by the exuding and encrusting 
sam Within. a _ short ee a ef ee oily oe of pale yellow colour collects in 
aA ae ay” Chem. Dep: 40 (1916), 559, Be. “) Hieree Tere Ut anaes 1915. — 4%) See illustrations in 
; _ original eaerre. 5 tips ae 1s ae Sas 
