172 



FARMERS' K E G I S T E 11 , 



[No.g 



tress of that kind, are little more than mere 

 ehellB. 



This Ia6t remark is not a» all inconsistent vviih 

 the one which immediately preceided it. Place 

 sap-wood and sound heart-wood in the same cir- 

 cumstances, and the latter will tar outlast the Ibr- 

 nier. Such is the situation of the two when used 

 as timber; but let the sap-wood retain its vitality, 

 whilst the heart-wood is dead, (and such is their 

 situation n the living tree,) and the former will far 

 outlast the latter. The power of the vital prin- 

 ciple to preserve organized matter from decay, is 

 eomething which we cannot explain ; but of which 

 we see evidence every where around us. Let a 

 leaf be severed from the parent-stem, and fall to 

 the ground, whilst another just by its side, retains 

 its connexion with that stem. The former, under 

 the combined agency of heat and moisture, soon 

 undergoes complete disorganization ; a part of it 

 rising into the atmosphere in the form of an invisi- 

 ble gas, whilst another part remains as earthy 

 mould, to mark the spot where it lell. The lat- 

 ter, under the action of the same agencies, goes 

 on unlblding itsel'j perfecting its structure, per- 

 forming its vital functions, and "dreams not of de- 

 cay," until the frosts of autumn bring it notice that 

 its work is done. In the possession of vitality, 

 living matter has a complete release, under the 

 hand and seal of the creator himself, Irom the ac- 

 tion of those agencies, which in ordinary circum- 

 stances would operate upon it. It is for the time 

 being, absolved from all obedience to the chemical 

 laws which govern common matter. This differ- 

 ence between living and dead matter is one which 

 should be borne in mind in all our reasoning re- 

 specting organized matter, as well vegetable as 

 animal ; the neglect of it has been a firuitflil source 

 of error in times past. 



Besides the peculiar secretions which are de- 

 posited in the heart-wood of most trees, there is 

 always more or less crude sap present, and often 

 other substances, which seem to hasten the decay 

 of the wood. The removal of these is the object 

 of the process called seasoning. There are three 

 ways of seasoning timber in common use. The 

 first is by exposing it the action of the sun and at- 

 mosphere. In this way the deleterious substances 

 are removed by evaporation. As these substan- 

 ces, when present, must of course occupy some 

 space in the wood, their removal diminishes its 

 size, If they be removed more rapidly from one 

 side of a plank, or stick of timber, than fi-om the 

 other, the contraction of the two sides must pro- 

 ceed at unequal rates. The effect of this is to curl 

 or warp the piece. On this account, it is advisa- 

 ble to season planks by the action of the at- 

 mosphere alone, without exposing them to the 

 direct action of the sun, as it is next to impossible 

 to have the sun act equally on both sides. Our 

 most experienced engineers and builders advise 

 that, in seasoning timber, it should be loosely piled 

 up, 80 that the atmosphere may have free access 

 to it on every side, and that it be kept under cover 

 thoughout the whole process. A second way of 

 seasoning is to expose the timber to artificial heat 

 in kilns. This process is in theory the same as 

 the first, ^^he only things to be atlended to in 

 adopting this method are, to place the timber in 

 such a way that all the parte of the same piece 

 ahall be exposed to about the same temperature ; 

 And to so regulate that temperature ae not to char 



the wood, A third way is to immerse the timber 

 in water. By this method we wash the injurious 

 substances out of the wood, instead of drying them 

 out. The vessels of wood, will of course, by this 

 process, become filled with water; but water 

 evaporates so much more easily than the sub- 

 stances with which the vessels of the wood are 

 naturally filled, that after the latter have been 

 washed out, the former will evaporate in the 

 course of a tew days. From the manner in which 

 water operates in seasoning timber, the reason 

 why a running stream is preferable to stagnant 

 water for this purpose, will be at once evident. 

 Fresh water is also better than salt, because al- 

 thouyh the latter will wash the wood as clean as 

 the former, yet when it is itself removed by eva- 

 poration, its water only evaporates, whilst the salt 

 which it contained is left behind. Salt being a 

 diliquescent substance, attracts moisture from the 

 atmosphere, and in this way the wood is kept con- 

 tinually more or less wet, to its great detriment as. 

 timber. 



Chap. VI. 



BARK OF EXOGEIVS. LIBER. CORTICAI, IN- 

 TEGUMENT, ENDOGENS, AGE AND SIZH 

 OF TREES. ACROGENS, 



The third and uttermost portion of the stem is the 

 bark. This consists of two distinct portions; an inner 

 fibrous portion, termed the liber, and an outer cel- 

 lular portion, termed the corticle integument. The 

 liber of some plants is remarkable for its suscepti- 

 bility of being split into very thin layers, which are 

 tough enouiih to be employed in the manufacture 

 of twine and cordage. It is from the liber of a 

 species of lime tree, (^tilia,) that Russian matting 

 is made. In the Sandwich Islands, a species of 

 cloth is manufactured from the liber of a tree com- 

 mon in those islands. In ancient times, the liber 

 of some trees was stripped into layers, flattened, 

 cemented into leaves, and used as a material to 

 write upon, instead of paper or parchment. At 

 the present day, a very good species of paper is 

 made from the same material as the Sandwich 

 Island cloth, and is used in those islands, both for 

 writing and printing upon. The liber of very ma- 

 ny of our common trees can be made into paper. 

 Some years since, a German paper-maker, pre- 

 sented to one of the scientific associations of Eu- 

 rope, a treatise on his art, written upon upwards 

 of thirty difiierent kinds of paper, made from the li- 

 ber of as many different kinds of trees, all of which 

 were indigenous of Germany. The woody fibre 

 of the hemp (cannabis sativa,) and flax, (Jinum, 

 asitatisswmm,^ so extensively used in the arts, 

 belongs to the liber, and not to the woody portion 

 of the stems of those plants. 



The bark increases in thickness, by the deposi- 

 tion of a new layer every year, between the origi- 

 ginal bark and the wood ; each new layer being 

 formed in a manner precisely similar to the first, 

 with this exception, that the cellular or spongy 

 part, being excluded from the air and light, does 

 not, become green, as in the first instance. That 

 a new layer is added to the bark internally, each 

 year, Da Hamel has proved by a very simple ex- 

 periment. He passed a metallic thread under the 

 innermost layer of the liber of a young free, and left 



