It is well known that Canadian timber is much more liable to decay than that grown in the northern parts of Europe, and for this reason is never extensively used in buildings of a superior description. The principle of decay being destroyed by Kyan’s process as above described, this objection no longer exists, and this kind of timber may therefore now be employed with as great security as that of a superior quality and higher price. The same observation applies with great force to timber of British growth, particularly to that of Scotland, much of which is considered as of little or no value for durable purposes, on account of its extreme liability to decay, whether in exposed situations or otherwise. The process invented by Kyan might therefore render of considerable value plantations of larch, firs of all kinds, birch, elm, beech, ash, poplar, &c. Cost of process in 1832, 1_l._ per load of 50 cubic feet of timber. Mr. W. Inwood, the architect of St. Pancras Church, London, reported favourably of Kyan’s process. On 22nd February, 1833, Professor Faraday delivered a lecture at the Royal Institution, London, on Kyanizing timber; and on 17th April, 1837, he reported that Kyan’s process had not caused any rusting or oxidation of the iron in the ship ‘Samuel Enderby,’ after the ship had been subjected to this process, and had been on a three years’ voyage to the South Sea fisheries; and in the same year, viz. 1837, Dr. Dickson delivered a lecture at the Royal Institute of British Architects on dry rot, recommending Kyan’s process. Five years after Mr. Kyan’s invention, viz. in 1837, a Mr. Flocton invented a process for preventing decay, by saturating timber with _wood-tar_ and _acetate of iron_, but little is known of this invention: we believe it was a failure. During the same year Mr. Flocton’s process was made known, a Frenchman named Letellier recommended saturating timber in a solution of _corrosive sublimate_, and when dry, into one of _glue_, _size_, &c.[9] During this year Mr. Margary took out his patent for applying _sulphate of copper_ to wood. We propose to describe Margary’s process further on: we do not think he received any medals for it.