----------------+---------+---------- -- | Wood | Chemical |(Spruce).|Wood Pulp. ----------------+---------+---------- Cellulose | 53·0 | 88·0 Resin | 1·5 | 0·5 Aqueous Extract | 2·5 | 0·5 Water | 12·0 | 8·0 Lignin | 30·5 | 2·5 Ash | 0·5 | 0·5 +---------+---------- | 100·0 | 100·0 ----------------+---------+---------- The use of mechanical wood pulp is generally confined to the manufacture of news, common printings and packing papers, cardboards, and boxboards. It possesses very little strength, quickly discolours when exposed to light and air, and gradually loses its fibrous character. The chemical wood pulp is a strong fibre, from which high-class papers can be manufactured, the colour and strength of which leave little to be desired. _Species of Wood._--The woods most commonly used for the manufacture of wood pulp belong to the order Coniferæ, or cone-bearing trees. In Europe the spruce and silver fir are the chief species, while in America spruce, balsam, pine, and fir are employed. The harder woods, such as hemlock, beech, larch and others, are not converted into pulp by the mechanical process. _Timber Operations._--The trees are cut down in the early part of winter by gangs of men specially trained to the work. The organisation of a lumber camp when the operations are of an extensive character is very complete and carefully arranged, every detail being attended to in order to get out the wood as cheaply and expeditiously as possible. The branches and small tops are removed from the trees when they are fallen, and the trunks cut into logs of 12, 14, or 16 feet in length, and afterwards piled up on the banks of the nearest river, or on the ice, ready for the breaking up of the winter. As soon as the ice breaks up and the rivers become navigable the logs are floated down to their destination, in some cases hundreds of miles from the scene of operations. Where rivers are not available the timber is brought out by horses or bullocks, or by means of a light railway. _Log Cutting._--As the timber arrives at the mill it is carefully measured, both as to its diameter and length, in order that a record may be kept of the quantity used. Some of the logs are piled up in the storeyard for use in the winter, and the remainder converted into pulp day by day. The logs are first cut into short pieces about 2 feet long by means of a powerful circular saw, the arrangements for this work being devised so as to keep down the cost of labour as much as possible. All waste pieces are thrown aside to be utilised as fuel.