284 A HANDBOOK OF CONIFERS 



Telegraph Poles for the Post Office. Memorandum to accompany 

 Tender Form No. 264, for home-gi-own poles — -Scots pine or larch. 

 The full range of sizes included in the specification is : 

 Light poles 18 to 60 ft. \ 



Medium poles 18 to 60 ft. [For details see page 6 of tender form. 

 Stout poles 26 to 85 ft. J 



The sizes of telegraph poles most commonly used in this country are : 

 Light. — 22 to 30 ft. in length, not less than 5 in. in diameter at the 

 top, and of a minimum diameter 5 ft. from the bvitt end of 6 J in. for 

 22 ft., rising to TJ in. for 30 ft. 



Medium. — 24 to 34 ft. in length, 5| to 6 inches minimum at top, 8 

 to 9j in. minimum at 5 ft. from butt. Also 36 and 40 ft. in length, 6 

 in. minimum at top, 9| and 9f minimum at 5 ft. from butt. 



Stout. — -32 to 50 ft. in length, Ih to 7f in. minimum at top, 11 to 

 13| in. minimum at 5 ft. from butt. 

 (All measurements are under bark.) 



In the case of larch the specifications requirements will be 

 modified as follows : 



Light poles. — 18, 20, 22, 24 ft., minimtmi diameter at top may be 4| in. 

 Medium poles. — All sizes minimum diameter at top may be \ in. less 

 than specified. 



Although larch poles and posts last longer than many coni- 

 ferous woods when placed in the ground in a natural state, their 

 life is greatly prolonged by creosoting the portion below and at 

 least 1 ft. above ground, the bark being removed in all cases. 



The bark has astringent, balsamic, and diuretic properties. 

 It has been used in tanning and dyeing, and also in medicine. 

 An oleo-resin known as Venice or Larch Turjjentine is obtained 

 by tapping, and an annual extraction of | lb. per tree can be 

 made without injury to the tree.^ It is of similar consistency 

 to Canada balsam and possesses medicinal properties. Its use, 

 however, appears to be confined to veterinary practice. A sub- 

 stance called Briancon Manna or Manna of the Larch ^ exudes 

 in the summer from the leaves. It is a white saccharine sub- 

 stance and is found in the early morning in the height of sum- 

 mer as opaque crystalline oblong tears enclosing the leaves and 

 without any well-marked odour, but having a sweet taste. It 

 contains a peculiar sugar called Melezitose, and was formerly used 

 in medicine. Ethyl alcohol^ is obtained by distillation of the 

 wood. 



L. europcea is the most widely grown and probably the most 

 valuable exotic tree in Britain. The general excellence of its 

 timber has led to its being planted under every conceivable con- 

 dition from sea-level to an altitude of 2,000 ft. in sheltered Scot- 

 tish glens. There have naturally been many failures, but, on the 

 other hand, where favourable conditions obtain, it has met with a 



^ Spon's Encychpoedia of the Industrial Arts, v, p. 1691 (1882). 

 ^ Bentley and Trimen's Medicinal Plants, iv, No. 260. 

 3 Raw Materials Review, Nov. 1922, p. 27. 



