Page:Timber and Timber Trees, Native and Foreign.djvu/249

XXVII.] THE HORNBEAM TREE (Carpinus betula)

is an indigenous British tree, which thrives well even upon a poor soil, and attains the height of 40 to 50 feet with a circumference of from 30 to 45 inches.

The wood is white in colour, close in the grain, hard, tough, strong, and of moderate weight; its pores are minute, the medullary rays are plainly marked, and there is no sap or alburnum; it may, therefore, be worked up to great advantage. Hence we find it employed for a variety of purposes; it is useful in husbandry, and agricultural implements made of the sound and healthy wood wear well, as it stands exposure without being much affected by it. It is also used by engineers for cogs in machinery, a purpose for which it is well suited.

The Hornbeam tree, if pollarded, becomes blackish in colour at the centre, owing to the admission of external moisture. This renders it unfit for many purposes where a clean, bright surface is required, and generally it proves detrimental to the quality and durability of the timber.

This wood when subjected to vertical pressure cannot be completely destroyed, its fibres, instead of breaking off short, double up like threads, a conclusive proof of its flexibility and fitness for service in machinery.

I was not able to secure suitable specimens of the standard dimensions to test the transverse strength of this wood, and consequently only the tensile and crushing or vertical strains appear in the tables.