| ANTHRACITE | BITUMINOUS | WOOD (AVERAGE) DRY. | PEAT | PEAT 1⁄4 WATER | |||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Carbon | 901⁄2 | 81 | 50 | 59 | 44 | ||||||||||
| Hydrogen | 21⁄2 | 51⁄4 | 6 | 6 | 41⁄2 | ||||||||||
| Nitrogen | 01⁄4 | 1 | 1 | 11⁄4 | 1 | ||||||||||
| Sulphur | 00 | 11⁄2 | 0 | ? | (25) | ||||||||||
| Oxygen | 21⁄2 | 61⁄2 | 41 | 30 | 221⁄2 | ||||||||||
| Ash | 41⁄4 | 43⁄4 | 2 | 33⁄4 | 3 | ||||||||||
| 100 | 100 | 100 | 100 | 100 | |||||||||||
In burning coal or other fuel atmospheric air must be introduced before it will burn; the air furnishes the oxygen, without which combustion cannot take place.
It is found that in burning one lb. of coal one hundred and fifty cubic feet of air must be used and in every day practice it is necessary to supply twice as much; this is supplied to the coal partly through the grate bars, partly through the perforated doors, and the different devices for applying it already heated to the furnace.
WOOD.
Wood as a combustible, is divisible into two classes: 1st, the hard, compact and comparatively heavy, such as oak, ash, beech, elm. 2d, the light colored soft, and comparatively light woods as pine, birch, poplar.
Wood when cut down contains nearly half moisture and when kept in a dry place, for several years even, retains from 15 to 20 per cent. of it.
The steam producing power of wood by tests has been found to be but little over half that of coal and the more water in it the less its heating power. In order to obtain the most heating power from wood it is the practice in some works in Europe where fuel is costly, to dry the wood fuel thoroughly, even using stoves for the purpose, before using it. This “hint” may serve a good purpose on occasion.
The composition of wood reduced to its elementary condition will be found in the table with coal.