Scientific and other notes on essential oils. 69 



The distillation of the turpentine from the following yearly yields according to 

 the cup-system produced a fine, light-coloured rosin as a residue which distinguished 

 itself most advantageously from that produced by the box-method. Besides this the 

 cup-system showed itself to be admirably adapted for obtaining turpentine from trees 

 with higher-reaching chippings. 



The results of the first experimental year were made known to the owners of the 

 forests and aroused much interest, but this soon diminished and could only be kept 

 alive by further efforts and by drawing attention to the commercial advantages of the 

 cup-system. Finally it was decided to give the cup-system a trial to a certain extent. 

 The good results obtained in the second year brought about a notable advance in the 

 matter, the box-system was gradually relegated to the "lumber-room", the new method 

 gained supporters and friends on all sides, so that finally the cup-method won the day 

 over the wasteful box-system at least in principle. Nowadays the authorities in the 

 Naval Stores regard the box-system as quite antiquated and various sorts of cups are 

 in use and current in trade. Even the railway companies of the Southern States have 

 gone so far as to arrange cheap freight-rates for the carriage of all the articles needed 

 in the cup-system. 



The reports of the results of the practical application of the cup-system in coniferous 

 woods gave proof of much larger yields in turpentine everywhere, but also pointed 

 out as a drawback that more extensive "chipping" was needed to fill the cups at the 

 beginning of the year than was necessary according to the old box-method. This was 

 a confirmation of the unexpected lesser yield in the trials with the cups at the end 

 of the first month. The underlying cause is probably the following: — 



According to Tschirch's opinion, the resin-ducts of every normally developed pine 

 tree contain a resin which is formed in the living tree during its process of growth 

 and is accordingly a purely physiological product. Tschirch calls these ducts "primary 

 resin-ducts". They Only produce very little crude turpentine on being "chipped". 

 Immediately after the chipping, however, numerous resin-channels are formed in the 

 fresh outside wood round the injured part and an "Anastomosis" (ramification) of the 

 vessels begins, from which crude turpentine flows abundantly as a balm for the wound 

 inflicted. This exudation is accordingly a pathological product and Tschirch calls the 

 channels which produce this gum "secondary resin-ducts". They require for their full 

 development about 5 weeks. This theory of Tschirch also explains satisfactorily why 

 the cup-system gave a lesser yield in the first test-month. With the box-system, after 

 the "boxes" had been cut out round the trees some time elapsed before the chipping 

 operation was performed. In the meantime, numerous secondary resin channels were 

 formed which gave off liquid resin abundantly on being chipped. With the cup-system, 

 on the contrary, chipping was begun with directly after the first incision and as a 

 result secondary resin channels were not formed first of all, accordingly the exudation 

 was scanty, but rose, however, very much after some weeks, when these resin channels 

 had appeared round the incisions and then discharged liquid resin abundantly. Accord- 

 ingly, it is imperative in the cup-system after fixing the pipes to the cross-cuts. of the 

 trunks, which are intended to conduct the liquid resin into the cups, to begin chipping 

 immediately, then to leave the trees alone, and only to chip again after a period of 

 5 or 6 weeks. By this means a full development of the secondary resin-ducts round 

 the incision and an abundant flow of turpentine is warranted. Practical experience 

 proved Tschirch's theory to be correct, and the cup-method produced under these 

 conditions much larger yields, so that theory had effectively supported practical ex- 

 perience. 



