2308 ARBORETUM AND FRUT1CETUM. PART III. 



not to collect resin more than five or six times from each tree. 3dly, Not to 

 scrape off the resin before the month of July or August of the year after that 

 in which the groove has been made, or its edges fresh-pared, in order to give 

 the resin time to harden, and the bark under it to heal sufficiently to prevent 

 the rain from rotting the wood ; and, 4thly, Not to make more than one groove 

 at a time upon a tree if it be small, or two if it be large ; and never to 

 make the grooves more than 4 ft. in length or, more than 1 in. or li in. 

 in width. Attempts have been made to show that resin may be procured 

 from trees artificially, without seriously injuring them ; and one author (M. 

 Burgsdorf ) asserts that, if the spruce fir has attained its full growth, all its 

 resin may be extracted from it without injuring the quality of the wood for 

 fuel or charcoal ; while another (M. Malus) assures us that the timber of the 

 tree may still be used even for the purposes of construction. Du Hamel, 

 Hartig, and most other authors, however, are of a very different opinion ; 

 Hartig having found that carrying the process of extracting the resin to an 

 extreme degree, not only renders the wood unfit for the purposes of con- 

 struction, but even makes it almost useless for fuel. In Sweden, and on the 

 southern shores of the Baltic, a similar opinion prevails ; and the resin is 

 there only collected from those trees which have been pruned; in which 

 case it generally oozes out from the wound. 



Mode of preparing the Burgundy Pitch, This pitch, or rather resin, is 

 principally made in the Vosges. The slightest scar in the bark of the tree 

 will be sufficient to make the resin ooze out ; but it must be observed that it 

 never flows to the ground like turpentine, but congeals as soon as it issues 

 from the wound, and remains attached to the bark in tears or crystals, 

 something like the gum of cherry trees. To procure the sap in abundance, it 

 is necessary, as we have already observed, to take off* a narrow strip of bark, 

 which is done with the broad end of the instrument before mentioned, or 

 with a small hatchet ; great care being taken not to wound the wood. The 

 resin from young trees is softer than that from old ones ; but it is always 

 dry enough to be put into bags, in which it is kept till a sufficient quantity 

 is collected. To prepare the pitch, it is first necessary to melt the resin ; 

 and, for this purpose, caldrons are set in masonry, in such a manner that 

 the fire only touches the bottom of the caldron; and the chimney is 

 carried to such a height, or to such a distance, as to prevent all danger 

 of the flame issuing from it being driven by the wind or other causes on the 

 resin. A quantity of water is then put into the caldron so as to fill it 

 4 in. or 5 in. high ; and into this the resin is put a little at a time, till the 

 caldron is about four fifths full. A gentle fire is then lighted below, 

 which is gradually augmented, till the water boils, and the resin is all melted. 

 It must now be gently stirred; after which, the fire is withdrawn, and the 

 resin is in a state for being purified. This is done by pouring the liquid 

 from the caldron into a bag made of coarse linen, which has been previously 

 wetted ; filling it not more than two thirds, and afterwards putting it under 

 a light press. The resin flows pure and clear into small casks made of 

 fir wood ; and in this state it is the yellow Burgundy pitch of commerce. 

 The refuse left in the sack, being pressed a second time, yields a blacker 

 resin, which is used for the same purposes as the colophony of the pine; 

 and what remains, after this has been pressed out, is burned in order to 

 make lampblack. In general, 100 lb. of resin, as collected from the tree, 

 yields >0ll>. of Burgundy pitch, and 2 lb. of colophony. Trees grown on 

 fertile soils arc said to yield a greater proportion of resin than those grown 

 on poor oils; and the pitch is said to be better when the resin has been 

 Collected in a hot dry summer, than in a cold and humid one. An essential 

 produced from the Burgundy pitch, by distillation; but it is very inferior 

 to spirit, of turpentine. A strong and vigorous spruce fir will yield, every 

 v < oud year, from 40 lb. to 60 lb. of congealed resin; and this may be col- 

 lated (or from /J) to gfi years, if no other value is set on the tree ; but, if the 

 collection of the lap be continued for this length of time, the tree becomes 



