262 Anatomical Description of the Fir Tree. 



portion of volatile oil and succiis coviviiiiiis. This tree grows 

 very spungy and soft ; and its juices, which appear scarcely 

 thicker than water, can he driven off with a very little heat, leav- 

 ing the fibres of the wood almost naked. Hence it is, that this 

 sort of timber, when moderately dry, will absorb nearlv haif its 

 own bulk of water, witiiout increasing its size in any degree be- 

 yond what it had when in full vegetation. 



This water being again evaporated, and leaving the fibres open 

 to the action and reaction of the atmosphere, the wood very 

 soon decays, l^llnv writes, that this tree was used for no other 

 purpose among the Romans, than to rend for laths, or to form 

 staves for coopers to make tubs and barrels, and a few thin 

 boards for pannels. 



The Siberian hunters of the ermine, when their fermenting 

 yeast, whidi they carrv with them, is spoiled by the cold, so 

 that it will not serve to make the acid liquor they call quass, 

 scrape off the alburnum, or half-formed wood, which is under 

 the bark of the fir tree, and digest it with water over the fire for 

 an hour. Thev then mix it with their rye meal, bury the dough 

 in the snow, and in twelve hours' lime find a new ferment pre- 

 pared. This is presumed to be a strong, if not a decisive proof, 

 that these juices contain a very large portion of caloric, and have 

 the power of resisting cold more than any other vegetable juice. 

 For although th.ere mav have been considerable heat in the 

 dough when buried, yet it might have been supposed, that the 

 snow would very soon have reduced the temperatvne to an equi- 

 librium with itself, or 32 degrees at least: and this must soon 

 have stopped the fermentation, for tliere appears no evidence, 

 that fern;cntation will go on at all under 3G degrees. The snow 

 also, in abstracting caloric, would have melted round the dough, 

 and the moisture thus produced would have had a further ten- 

 dency to resist the fermentation. 



These juices then have the power of retaining caloric sufficient 

 to protect the vital principle of the plants, to which they be- 

 tong, against a greater intensity of cold than the juices of most 

 other plants. 



In this country, or perhaps any other of equal temperature, if 

 a great number of fir trees, or even small clumps of them, be 

 planted togetlier on any plain, for ornament or use, where there 

 is no shelter from one side more than another, they arc generally 

 found to thrive best on the north side of the clump. The reason 

 is, that those on the south side shelter them from the direct rays 

 of heat, though the heat or general temperature of the day may 

 be nearly as high on the north as on the south side. A few in- 

 stances of this fact near London may be mentioned. In the 



whole 



