kettle to retain the heat and economize fuel.
Next a rectangular pan of sheet-iron was substituted for the kettle, and
a shed or rude house was built around the arch. The process of
improvement has continued, until to-day in most of the larger orchards
can be found neat and convenient sugar-houses, with closely-built arches
of brick; while in place of the ancient caldron kettle, or the still
much-used sap-pan, it is common to find the modern evaporator.

There are several patterns of evaporators in use. The most common one
consists of a pan of from twelve to sixteen feet in length and four or
five in width, divided into compartments by a series of partitions which
run nearly across the pan, at intervals of six or eight inches, but at
alternate ends stop three or four inches short of the side. Thus all the
compartments are connected with each other in such a manner as to form
one winding passage-way.

Back of the arch, and at one corner, stands a large hogshead containing
sap, with a faucet at the bottom, and a small tube opening into the rear
compartment of the evaporator. This tube has a self-acting valve, which
closes when the sap has reached the proper height in the pan, and opens
again when it has been lowered by boiling.

When the sap is first turned on it at once runs through the entire
passage-way, and covers the bottom of the pan. Thenceforward it enters
slowly, and is heated gradually in the rear compartments, while the
boiling is confined to the front portion of the pan.

The density of this boiling portion of the liquid is constantly
increased by evaporation; and the fresh sap, instead of mixing
intimately with the boiling mass, acts as a pressure in the rear,
forcing it steadily towards the front. Soon the different compartments
of the evaporator present the saccharine fluid in all its phases, from
fresh, cool sap, through warm, hot, and boiling, then partially
concentrated, then thin syrup, then thicker, and, if the process be long
enough continued, even down to sugar. It is customary, however, to draw
it off through another faucet in front when it has reached the
consistency of syrup.

In the smaller orchards, the sap is usually gathered in pails and
brought directly to the central reservoir. For this purpose a sap-yoke
is borne on the shoulders, with a large pail suspended from each end. In
larger orchards, where the ground is not too rough, a barrel or hogshead
is fastened upon a sled and drawn thro