These trials have not, indeed, all the precision needful to fix with accuracy the comparative heating effect of the fuels employed; for a furnace, that is adapted for wood, is not necessarily suited to peat, and a coal grate must have a construction unlike that which is proper for a peat fire; nevertheless they exhibit the relative merits of wood, peat, and anthracite, with sufficient closeness for most practical purposes.
Two considerations would prevent the use of ordinary cut peat in large works, even could two and one-fourth tons of it be afforded at the same price as one ton of coal. The Nassau Water Department consumes 20,000 tons of coal yearly, the handling of which is a large expense, six firemen being employed to feed the furnaces. To generate the same amount of steam with peat of the quality experimented with, would require the force of firemen to be considerably increased. Again, it would be necessary to lay in, under cover, a large stock of fuel during the summer, for use in winter, when peat cannot be raised. Since a barrel of this peat weighed less than 100 lbs., the short ton would occupy the volume of 20 barrels; as is well known, a ton of anthracite can be put into 8 barrels. A given weight of peat therefore requires 2-1/2 times as much storage room, as the same weight of coal. As 2-1/4 tons of peat, in the case we are considering, are equivalent to but one ton of coal in heating effect, the winter's supply of peat fuel would occupy 5-5/8 times the bulk of the same supply in coal, admitting that the unoccupied or air-space in a pile of peat is the same as in a heap of coal. In fact, the calculation would really turn out still more to the disadvantage of peat, because the air-space in a bin of peat is greater than in one of coal, and coal can be excavated for at least two months more of the year than peat.
It is asserted by some, that, because peat can be condensed so as to approach anthracite in specific gravity, it must, in the same ratio, approach the latter in heating power. Its effective heating power is, indeed, considerably augmented by condensation, but no mechanical treatment can increase its percentage of carbon or otherwise alter its chemical composition; hence it must forever remain inferior to anthracite.