In 1817 Mr. William Chapman published the result of various experiments he had made on wood with _lime_, _soap_, and _alkaline_ and _mineral salts_. He recommended a solution of a pound of _sulphate of copper_ or blue vitriol (at that time 7_d._ per pound) dissolved in four ale gallons of rain water, and mopped on hot over all the infected parts, or thrown over them in a plentiful libation. He also recommended one ounce of _corrosive sublimate_ (then 6_s._ per pound) to a gallon of rainwater applied in the same manner to the infected parts. For weather-boarded buildings he considered one or more coats of thin _coal tar_, combined with a small portion of _palm oil_, for the purpose of preventing their tendency to rend, to be a good preservative. Messrs. Wade, Boydon, and Chapman published works on dry rot about this time. In 1822 Mr. Oxford took out a patent for an improved method of preventing “decay of timber,” &c. The process proposed was as follows: “The essential _oil of tar_ was first extracted by distillation, and at the same time saturated with _chlorine gas_. Proportions of _oxide of lead_, _carbonate of lime_, and _carbon of purified coal tar_ well ground, were mixed with the oil, and the composition was then applied in thick coatings to the substances intended to be preserved.” On 31st March, 1832, Mr. Kyan patented his process of _corrosive sublimate_ (solution of the _bi-chloride of mercury_) for preventing dry rot; which process consisted as follows: A solution of the corrosive sublimate is first made, and the timber is placed in the tank. The wood is held down in such a way, that when immersed on the fluid being pumped in, it cannot rise, but is kept under the surface, there being beams to retain it in its place. There it is left for a week, after which the liquor is pumped off, and the wood is removed. This being done, the timber is dried, and said to be prepared. Sir Robert Smirke was one of the first to use timber prepared by Kyan, in some buildings in the Temple, London; and he made some experiments on timber which had undergone Kyan’s process. He says, “I took a certain number of pieces of wood cut from the same log of yellow pine, from poplar, and from the common Scotch fir; these pieces I placed first in a cesspool, into which the waters of the common sewers discharged themselves; they remained there six months; they were then removed from thence, and placed in a hotbed of compost under a garden-frame; they remained there a second six months; they were afterwards put into a flower border, placed half out of the ground, and I gave my gardener directions to water them whenever he watered the flowers; they remained there a similar period of six months. I put them afterwards into a cellar where there was some dampness, and the air completely excluded; they remained there a fourth period of six months, and were afterwards put into a very wet cellar. Those pieces of