Webster Herrick was in business from 1854 or earlier until 1874 or later.
Information Sources
From ad in 1854-1856 issues of Scientific American. The 1856 ads read, "CIRCULAR SAW MILLS—The subscriber has on hand, and is constantly manufacturing these celebrated mills with saws from 30 to 80 inches diameter, adapted to manufacturing most kinds of lumber, and warranted to give satisfaction. For prices, &c., address W. HERRICK, Northampton. Mass."
An 1866 letter to the editor of Scientific American mentions W. Herrick, in passing, as a maker whose circular sawmills do not allow lateral motion of the blade, and whose mills are in successful use.
An 1867 patent for a sawmill carriage was granted to Webster Herrick of Northampton, MA.
Ben Campbell reports a listing in an 1869 directory: "W. HERRICK Northampton Mass." “Machinist and manufacturer of patent portable circular saw mills” also “siding and box board mills” & “planning machines”
Listed in the 1874 work, Wiley's American iron trade manual of the leading iron industries of the United States as a maker of circular saw mills.
"CITY DOCUMENT NO. 5: ANNUAL REPORTS OF OFFICERS OF THE CITY OF NORTHAMPTON, MASS.
FOR THE YEAR ENDING NOVEMBER 30, 1888" lists Webster Herrick as "paid by city for services".
A genealogy website lists "HERRICK, Webster / b. 11 NOV 1811 Sangerfield, NY." On 1840-07-02 he married Melissa Strong of Northampton. They had one child, Charles Edward Herrick, born 1848-01-17.