History of Saginaw county, Michigan; together with ... portraits ... and biographies ... History of Michigan ...

428

HISTORY OF SAGINAW COUNTY.

three hours, the bitter water containing the earthy chlorides being
thus drained off. Thorough drainage is considered an important
point in this mode of manufacture. The balance of the brine or
bitter water remaining in the kettle is now bailed out and thrown
into the drainage trough. The kettle is then rinsed out with fresh
water and again filled up with brine.
The difference of the time in which the front and the back kettles boil down varies from four hours in the front to 12 hours
in the back. The kettle blocks are generally run day and night
by four men, two boilers and two firemen, taking turns of 12
hours each. The average product of a good kettle block is 75 barrels of salt per day of 24 hours.
This process is rapidly becoming superseded by the more economical one of pan and steam blocks.
In Pan Blocks.-Pan blocks are buildings of various dimensions,
built to accommodate the size of the pan, settlers and salt bins.
The pans are made of quarter-inch boiler-plate iron. They vary
from 90 to 120 feet in length, being divided into sections of 30 or
40 feet, are 12 to 15 feet wide, and from 10 to 12 inches deep.
With some the sides are straight, the salt being raked to the side,
lifted out with a shovel and thrown on the draining boards. In
others the sides are flanged, and the salt is raked directly on to the
draining boards. Pans of the above size rest on three walls as in
kettle blocks, the arches running directly under the pan to the
chimney at the end. As the firing of these blocks is done mostly
with slabs or light fuel, the first 30 or 40 feet are also protected
by patent arches thrown across the flues, thus dividing the heat
more generally throughout the block. The brine boils very rapidly
in these blocks, and as the salt makes fast it requires nmuch care
and attention on the part of the workmen to keep the salt from
baking on the bottom of the pan; this is prevented by raking out
the salt almost as fast as it makes.
Improvements in heating pan blocks have been made of late
years in those localities where the price of fuel is a consideration.
A pan block of an improved plan for boiling the brine has been
erected by Ayres & Co., of Port Austin, Huron county. The
block is 120 feet long, 43 feet wide, outside posts 10 feet high and
center post 18 feet high-almost too high to carry off the steam in
winter. The length was also calculated for four pans. Three pans
only were put on, being each 30 feet long and 16 feet wide on bottom, sides flanging and bolted to the draining boards. The
pans rest on seven walls, which are so arranged that they make two
fire flues in the center and two return flues on the sides. The center and outside walls run the entire length and width of the pan.
All the walls are a foot wide at the top. The two fire flues which
are under the middle of the pan on both sides of the center wall
are 2- feet wide. Height of grate to pan, 31 feet. The return flues
are next to the outside walls, under the sides of the pan, and are
two feet wide. This gives a heating surface of 180 feet in length