446 THE UNIVERSE. 



It is this secretion that gives to the coniferous woods 

 such power of endurance; the more it abounds in their 

 resinous ducts, the greater lapse of ages can they endure. 

 The wood of the Canary Islands pine {Pinus canariensis) 

 is quite impregnated with it, and is therefore almost im- 

 perishable. The ancient dwellings in Teneriflfe, which 

 were entirely built of this wood more than four centuries 

 and a half ago, when the island was conquered, are quite 

 as fresh as when they were built. The resin still exudes 

 from all their beams during the heat of summer. 



Some plants, instead of distilling their resinous pro- 

 ducts drop by drop, form a gaseous vapour, and this clings 

 so close around the plant, that if, during the twilight of 

 a still, burning hot summer day, we approach it with a 

 lighted candle, the vapoiu' takes fire, and produces a bright 

 light which envelops all the foliage, sparkling like the 

 lycopodium burned in the theatres on the torches of the 

 Furies. This can be seen in the Fraxinella cultivated in 

 our gardens. Should the atmosphere be less ti^anquil, 

 the experiment is easily made by surrounding the plant 

 with a glass case, as is seen in our engraving. So soon 

 as an ignited body is plunged into it, a general combustion 

 ensues. 



Other plants, during darkness, project inexplicable 

 gleams of light. This extraordinary phenomenon, which 

 is attributed to electricity, was first pointed out by 



recommence at the foot of the tree, and cut others alongside of and jiarallel to 

 them. 



In the Coniferi'E which exude turpentine this substance is contained in 

 vertical or horizontal lacunae, which are called resin-ducts. Their wood is more 

 enduring in proportion as it contains more resin. The Canaiy pine {Pinus can- 

 ariensis) is remarkable in this respect. It contains a great number of these 

 ducts, which, according to Schacht, are sometimes -in of a millimetre in diameter 

 (a millimetre is rather less than the twenty-fifth or '039371 of an inch), hence 

 this wood is almost incorruptible. — Schacht, Les Arbres. Bruxelles, 18C2, p. 225. 



