The committee also forbears from discussing the merits of the many patents which have been taken out for wood preservation. It had prepared a list of them, and investigated the probable success of many of them, but has concluded that it is better to confine itself to the results of actual tests, and to stick to ascertained facts. Neither does the committee feel called upon to point out the great importance of the subject, and the economical advantages which will result from the artificial preparation of wood as its price advances. They hope, however, that the members of this Society, in discussing this report, will dwell upon this point. We shall instead give as briefly as possible the general conclusions which we have reached as the result of our protracted investigation. DECAY OF TIMBER. Pure woody fiber is said by chemists to be composed of 52.4 parts of carbon, 41.9 parts of oxygen, and 5.7 parts of hydrogen, and to be the same in all the different varieties. If it can be entirely deprived of the sap and of moisture, it undergoes change very slowly, if at all. Decay originates with the sap. This varies from 35 to 55 per cent. of the whole, when the tree is felled, and contains a great many substances, such as albuminous matter, sugar, starch, resin, etc., etc., with a large portion of water. Woody fiber alone will not decay, but when associated with the sap, fermentation takes place in the latter (with such energy as may depend upon its constituent elements), which acts upon the woody fiber, and produces decay. In order that this may take place, it is believed that there must be a concurrence of four separate conditions: 1st. The wood must contain the elements or germs of fermentation when exposed to air and water. 2d. There must be water or moisture to promote the fermentation. 3d. There must be air present to oxidize the resulting products. 4th. The temperature must be approximately between 50° and 100° F. Below 32° F. and above 150° F., no decay occurs. When, therefore, wood is exposed to the weather (air, moisture, and ordinary temperatures), fermentation and decay will take place, unless the germs can be removed or rendered inoperative. Experience has proved that the coagulation of the sap retards, but does not prevent, the decay of wood permanently.[1] It is therefore necessary to poison the germs of decay which may exist, or may subsequently enter the wood, or to prevent their intrusion, and this is the office performed by the various antiseptics. [Footnote 1: Angus Smith, 1869, "Disinfectants." S.B. Boulton, 1884, Institution Civil Engineers, "On the Antiseptic Treatment of Timber."]