346 TIMBER AND TIMBER TREES. [CHAP. 



those parts of the frames of ships in which a Hght 

 material is considered desirable. 



It is stated on good authority that the greater 

 number of the houses in Venice are built upon piles of 

 this timber, particularly those of which the supports 

 are alternately exposed to wet and dry; many of these 

 piles, after being in place for ages, are said not to have 

 the least appearance of decay. 



This wood evidently stood in high favour in early 

 times, Julius Caesar — who called it " Lignum igni im- 

 penetrabile," because he could not burn it with the same 

 facility as other timber — used it for every purpose when- 

 ever he could obtain it. Tiberius Csesar brought it 

 over long distances from the forests of Rhaetia for the 

 reparation of several bridges, and Pliny relates that a 

 Larch tree, measuring 120 feet long and 2 feet in 

 thickness, from end to end, was intended to be used in 

 one of these. It was, however, preserved for a long 

 time as a curiosity, and ultimately employed in the 

 building of a large amphitheatre. 



The Polish Larch tree is generally of straight growth, 

 and of dimensions rather exceeding the Italian variety. 

 It is also coarser in the grain, more knotty, and has 

 a larger amount of alburnum, or sap-wood. 



The Russian Larch tree attains dimensions superior 

 to either of the foregoing descriptions. A cargo of this 

 timber, very long and straight, was imported into this 

 country a few years since from the district of the Petchora, 

 a river flowing from the Ural Mountains into the Arctic 

 Ocean. 



It has been employed experimentally in ship- 

 building in Woolwich Dockyard, for deck anJ planking 



