INVENTION OF ROLLER FLOUR MILL.

each set, and the succeeding set of rolls." This system is now
the universal practice in milling throughout the civilized world.
To offset a possible attempt to overcome his roller system
operated in pairs, he devised and applied for a patent on
December 16, 1879, for a "Grinding Mill," having a single roll
and a concave stationary face between which the grain was to
pass. Patent No. 230,834 was issued to John Stevens for this
on August 3, 1880. On November 4, 1880, he applied for a
patent on a dial indicator devised so the operator could in-
stantly adjust the rolls to each other. The patent issued the
next month, December 28, 1880, numbered 236,104. The appli-
cation for this was witnessed by the late Hon. Robert Shiells,
and Mr. Alex. McNaughton. In December 16, 1879, he made
application for a blunt non-cutting crest, dressing of the rolls
to supplement his system; and later patent was issued Janu-
ary 24, 1882, No. 252,705.   December 29, 1882, Mr. Stevens
made application for a patent on his complete roller mill frame
and housing with adjustments designed, for single sets in one
frame or double sets. This was witnessed by Mr. J. P. Shiells
and the late Mr. Alex. McNaughton. Letters patent was issued
September 2, 1884, No. 304,463.
These are the six essential patents Mr. Stevens obtained in the
invention of the roller mill. The first two given are the basic
invention, which places his name high in the annals of inven-
tion. As soon as his mill was fitted, and operated at fabulous
profits by the new system, it was next to impossible to keep it
to himself. Very soon all the local machine shops were engaged
nights and Sundays in secretly trying to form roller sets.
Other machine shops did get at the system and mill furnishing
concerns vied with each other in devising roller mills. The
issue of his patent hung so long in the patent office that by
1880, when the patent was finally issued, the system had been
mentioned in the press and talked of for six years.1
In 1878 occurred the great flour mill fire in Minneapolis, the
one that was attended with disastrous explosion of the flour
mill dust, and loss of life. Governor Washburn and others re-

1. In "History of Winnebago County," by Richard J. Harney, published
in 1880, he states under date of 1879, that "these mills at Neenah are
chiefly large substantial structures with all modern improvements in flour
mill
n achinery, to which within the last two years has been added the new
patent machinery for the manufacture of patent flour. Patent flour now
constitutes about eighty per cent of their product."

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