Rensselaer Semi-Weekly Republican, Volume 20, Number 104, Rensselaer, Jasper County, 8 September 1899 — “Straight Edge” an impossibility. [ARTICLE]

“Straight Edge ” an impossibility.

One of the difficult problems in pra&>J9 tical mechanics is to make a li iil|||iM edge.” How difficult it is may be iPdjjlß ed from an incident which occurred Ini® the shops of J. A. Brashear, the astron-J----omical instrument maker. A customoH asked Mr. Brashear what would be thj|« price of “a perfect straight edge <*fll glass thirty-six inches long.” "It can’ll be made absolutely perfect,” said Mfjl Brashear, “but it could probabtyliH made with a limit of error amonattofll: to only a fraction of a wave length afii light.” “How much would that ea*4?“J 1 “About |40,000!” It turned out tbi|l the customer wanted the straight edge® for a scraper, and that an error of on*® sixty-fourth of an inch would haljiH been insensible for his purpose. J