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Oliver Blackburn Shallenberger (May 7, 1860 – January 23, 1898) was an American electrical engineer and inventor. He is associated with electrical inventions related to alternating current.
A wrought iron ruler, the Toise of Peru, also called Toise de l'Académie, was the French primary standard of the toise, and the metre was officially defined by an artifact made of platinum kept in the National Archives. [36] Besides the latter, another platinum and twelve iron standards of the metre were made by Étienne Lenoir in 1799. [37]
In response to formal requests made by the International Union of Pure and Applied Physics and by the French government to establish a practical system of units of measure, the CGPM requested the CIPM to prepare recommendations for a single practical system of units of measurement, suitable for adoption by all countries adhering to the Metre ...
When means for weighing were invented, seeds and stones served as standards. For instance, the carat, still used as a unit for gems, was derived from the carob seed.
Saturdays were made half holidays to promote community involvement and personal development. [45] [46] Westinghouse had observed the practice while visiting England. The planned community of Wilmerding, Pennsylvania was home to many Westinghouse employees, and it was also the headquarters of several companies, particularly Westinghouse Air Brake.
1885 — Calender-Van Duesen invented the platinum resistance temperature device; 1887 — Richard Assmann invents the psychrometer (Wet and Dry Bulb Thermometers) 1892 — Henri-Louis Le Châtelier builds the first optical pyrometer; 1896 — Samuel Siegfried Karl Ritter von Basch introduced the Sphygmomanometer to measure blood pressure
John Edgar Thomson (February 10, 1808 – May 27, 1874) was an American civil engineer and industrialist. An entrepreneur best known for his leadership of the Pennsylvania Railroad (PRR) from 1852 until his death in 1874, Thomson made it the largest business enterprise in the world and a world-class model for technological and managerial innovation.
The Birth of Pennsylvania, a portrait of William Penn (standing with document in hand), who founded the Province of Pennsylvania in 1681 as a refuge for Quakers after receiving a royal deed to it from King Charles II. The history of Pennsylvania stems back thousands of years when the first indigenous peoples occupied the area of present-day ...