Soon after the first graduating machine was put into use, the vernier caliper, reading to thousandths of an inch, was brought out by Mr. Brown; the first was made as early as 1851. In the following year he applied the vernier to protractors. A writer, in speaking of the invention of the vernier caliper, says, “It was the first practical tool for exact measurements which could be sold in any country at a price within the reach of the ordinary machinist, and its importance in the attainment of accuracy for fine work can hardly be overestimated.” The introduction of the vernier caliper was slow, only four being made in the first year. In 1852 Mr. Brown asked the New York agents to return one which they had on exhibition because he needed it for some fine work and did not have another in the shop. Within a year or two the sales improved, for Mr. Sharpe wrote his agent at Newark, N. J., in 1854, that it could not be expected there would be a market for many more tools in that neighborhood, as $500 worth had already been sold there. Mr. Brown did not have the market long, for in 1852 Samuel Darling also invented and built a graduating engine and began the manufacture of rules and squares at Bangor, Maine. Mr. Darling had been a farmer and sawmill owner, with a strong bent for mechanics. He had gone to work in a machine shop six years before and almost from the first had given his attention to improvements in machinists’ tools. His first partner was Edward H. Bailey, but after a year a new partnership was formed with Michael Schwartz, a saw maker and hardware dealer of Bangor. They soon became active competitors of J. R. Brown & Sharpe, and to this day mechanics here and there have scales marked “D. & S., Bangor, Me.” Competition between the two firms, both in prices and quality of work, became so keen that a truce was called in 1866, resulting in the formation of the partnership of Darling, Brown & Sharpe, which conducted this part of the business until 1892, when Darling’s interest was bought out. The entire business was soon after conducted under the name The Brown & Sharpe Manufacturing Company, the original firm of J. R. Brown & Sharpe having been incorporated under that name in 1868. In the spring of 1868 Mr. Darling moved to Providence, bringing with him his graduating engine, machinery and six of his most experienced workmen. Darling’s engine was built along radically different lines from Brown’s, an interesting feature being that many of its parts were made of saw-stock, which he also used as the material for his scales and squares. His machines and processes had been kept secret, and it was not until after the partnership was formed that Mr. Brown had opportunity of seeing them at Bangor. Mr. Darling’s original dividing machine is also still running at the Brown & Sharpe works, having been operated for over fifty years by John E. Hall, who remembers the time when Mr. Darling first brought his new partners to see it.