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Easco continued the Craftsman contract with Sears. By 1969, the parent company was known as Easco Corporation. [1] Tools made by MDF for Sears have a "V" maker's mark on them, those by Danaher had a "V^" (V and upside down V, sometimes a right-side up V). Variations of the "VV" exist including three digit codes on tools such as ratchets.
The business was relocated to Brooklyn in 1884 and took the name J.H. Williams & Co in 1887. The company was one of the first to offer mass-produced drop-forged hand tools. [3] A second factory was opened in Buffalo, New York in 1914, now the site of General Motors' Tonawanda Engine plant. [4] The company was acquired by Snap-on in 1993.
The Craftsman trademark was registered by Sears on May 20, 1927. [2] Arthur Barrows, head of the company's hardware department, liked the name Craftsman and reportedly bought the rights to use it from the Marion-Craftsman Tool Company for $500 (equivalent to $8,770 in 2023). [3] The brand's early customers were mostly farmers.
Compound microscopes first appeared in Europe around 1620. [ 2 ] [ 3 ] The actual inventor of the compound microscope is unknown although many claims have been made over the years. These include a dubious claim that Dutch spectacle-maker Zacharias Janssen invented the compound microscope and the telescope as early as 1590.
13th century: The increase in use of lenses in eyeglasses probably led to the wide spread use of simple microscopes (single lens magnifying glasses) with limited magnification. [2] 1590: earliest date of a claimed Hans Martens/Zacharias Janssen invention of the compound microscope (claim made in 1655). [3] [4]
Antonie van Leeuwenhoek (1632–1723). The field of microscopy (optical microscopy) dates back to at least the 17th-century.Earlier microscopes, single lens magnifying glasses with limited magnification, date at least as far back as the wide spread use of lenses in eyeglasses in the 13th century [2] but more advanced compound microscopes first appeared in Europe around 1620 [3] [4] The ...
There are two basic types of optical microscopes: simple microscopes and compound microscopes. A simple microscope uses the optical power of a single lens or group of lenses for magnification. A compound microscope uses a system of lenses (one set enlarging the image produced by another) to achieve a much higher magnification of an object.
Whilst compound microscopes were first developed in the 1590s, the significance of the microscopic scale was only truly established in the 1600s when Marcello Malphigi and Antonie van Leeuwenhoek microscopically observed frog lungs and microorganisms. As microbiology was established, the significance of making scientific observations at a ...