Page:Timber and Timber Trees, Native and Foreign.djvu/346

326 The decay and waste between July, 1869, and April, 1871, was very rapid, but the condition of the carbonised and non-carbonised specimens was much the same; it leaves, therefore, little to say in favour of the charring process, and I should not myself be inclined to use it on timber for works of construction, except as a possible means of preventing the generation of moisture or fungus where two unseasoned pieces of wood are placed in juxtaposition.

An experiment in carbonising was tried on a piece of plank 5 feet in length, one-half the breadth being charred, the other not; this was set in the ground under the drip of a roof. In another case a piece of plank was charred over half its length, the other not. Plates of iron were then secured to each end, and the whole immersed in water to ascertain whether the carbonising of the surface would prevent oxidation. When, however, each of these were examined, some six months later, it could not be seen on which side to give the preference.

The wood backing to the armour plates on the starboard side of H.M.S. "Caledonia" was charred by M. de Lapparent's process, with the view to test its efficacy thoroughly, and when this ship comes under repair it will be ascertained by comparison with the other side how far it is useful in preventing decay. The Admiralty also ordered the faying surfaces of the frame timber and planking of the "Tenedos" and "Spartan," the former building at Devonport, and the latter at Deptford Dockyard in 1868, to be carbonised by this process, in the hope that it will retard the formation of fungus on the surfaces, on which it frequently forms with rapidity; but, as neither of these ships have yet been opened for repairs (1875), it is uncertain whether any good results have come of the experiment.