Below, details from an old framing square I picked up:
In 1901, Moses Nichols patented a square (Patent No. 672455) incorporating a rafter table for computing common rafter lengths including hip and valley lengths. His square was revolutionary for the time, and remained the standard for more than a century. He formed the Nichols Manufacturing Company in Ottumwa, Iowa and was later bought out by his partners. As the author of the Ottumwa Iron Works explains:
"Ottumwa, like many small towns, had a variety of industries. Most towns of 10,000 population and up had a grey iron foundry. Wherever there was a foundry, many small manufacturers sprang up. Most of the smaller ones are no longer in operation."
It would seem that the Nicholls Company was acquired by the Sands Level & Tool Company of Wichita, Kansas at some point, or vice-versa. In 1885, a bricklayer named Julius Sands invented the "solid set" vial for levels. He eventually also developed the first aluminum level. Sands Level and Tool was purchased by Harmon Incorporated and in 2005 acquired by the Kraft Tool Company which continues to offer levels under this brand name, with the motto: "Sands Level Tell The Truth." Cute.
Interestingly, the tool shown in the photo above reads "Since 1896" yet the Kraft Tool Company proclaims that Sands was established in 1895.