DISCUSSION. ON THE DECAY OF MATERIALS IN TROPICAL CLIMATES, AND THE METHODS EMPLOYED FOR ARRESTING AND PREVENTING IT
Minutes of the Proceedings of the Institution of Civil Engineers
remarked, that he had sent out to Bombay both creosoted and kyanised sleepers : native jungle-wood had also been used. H e regretted he could not give the details of the results of these several experiments. He.could, however, state this general fact, which was of much practical value : the resident Engineer of the Great Indian Peninsula Railway, after an experience of thirteen years in India, was now replacing large numbers of sleepers which had failed, with teak and iron sleepers. Attempts
... e made, in the first instance, to preserve the native wood by the usual processes ; but, he believed in consequence of the wood being so hard and close-grained, it was impossible to impregnate it sufficiently with the preservative material. Keys were a matter of considerable difficulty in warm and variable climates. It had been reported to him, that the wooden keys (which were, he feared, perhaps not made with the utmost care,) dropped out in great numbers, and he was now giving his attention to the introduction of some other kind of key, which would answer the purpose better than the wooden ones. With respect to the preservation of iron, the result of his experience was, that whether for rails or bridge-work, iron should be thoroughly cleaned and dried by heat, and be then dipped into hot linseed oil. In the first instance, iron-work was sent out to Bombay not so treated, and the oxidation was excessive ; but since that plan had been adopted, the oxidation was prevented, and the rails and other iron-work remained in a perfect state. On the subject of rolling stock, it was stated in Mr. Mann's Paper, that the carriages on the Great Indian Peninsula Railway were sent out with teak panels. If that were so, it was at a very early period, and before he had much voice in the matter. For some years past, the carriages had been sent out with ' papier mBch4 ' panels ; but notwithstandin his own opinion that it was the best material for the purpose, t a e locomotive superintendent, who ought to know better than himself, had expressed a desire that the anels should be of teak, and not of ' papier m8chB.' Mr. AAWKSHAW, Past-President, said, he had spent three years of his early life in a tropical climate, close to the equator, and had had some experience with regard to what timber would do in a country which Humboldt declared to be the hottest part of' the world. H e had also had many years' experience of Indian and of foreign railways, and of the duration of the rolling stock, sleepers, and iron-work sent out to those countries. He would say, with regard to timber generally, that being an organic substance, it was impossible for any one to predicate what it would sustain under the varying circumstances in which it was employed in those countries, or, indeed, elsewhere. For instance, he had known yellow pine, which, according to the statements of Downloaded by  on [12/09/16].