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[1] A simple, so-called "lateral" harmonograph uses two pendulums to control the movement of a pen relative to a drawing surface. One pendulum moves the pen back and forth along one axis, and the other pendulum moves the drawing surface back and forth along a perpendicular axis.
By 1900, two primary types of mimeographs had come into use: a single-drum machine and a dual-drum machine. The single-drum machine used a single drum for ink transfer to the stencil, and the dual-drum machine used two drums and silk-screens to transfer the ink to the stencils. The single drum (example Roneo) machine could be easily used for ...
A Polygraph is a duplicating device that produces a copy of a piece of writing simultaneously with the creation of the original, using pens and ink. Patented by John Isaac Hawkins on May 17, 1803, it was most famously used by the third U.S. president, Thomas Jefferson , who acquired his first polygraph in 1804 and later suggested improvements ...
This second phase brought to mass markets technologies like the small electric motors and the products of industrial chemistry without which the duplicating machines would not have been economical. By bringing greatly increased quantities of paperwork to daily life, the duplicating machine and the typewriter gradually changed the forms of the ...
The cyclostyle, which is an instrument used for multiple writing, makes about 140 dots to the inch. The style has a minute spur-wheel or roller, instead of a [pen] point ; the writing is made on stencil paper, whose surface is covered with a brittle glaze. This is perforated by the teeth of the spur-wheel wherever they press against it.
In organic chemistry, phenols, sometimes called phenolics, are a class of chemical compounds consisting of one or more hydroxyl groups (−O H) bonded directly to an aromatic hydrocarbon group. [1] The simplest is phenol, C 6 H 5 OH. Phenolic compounds are classified as simple phenols or polyphenols based on the number of phenol units in the ...
The writing on the picture indicated that it was drawn by Maelzel's automaton which was known at the time as the Maelzel's Juvenile Artist. It is believed that at least one member of the Minot family witnessed the drawing by the Juvenile Artist at the exhibition of Johann Nepomuk Maelzel's automata in Boston on April 29, 1835. The Massachusetts ...
Since that time phenol has become the chemical of choice for chemical matrixectomies performed by podiatrists. Concentrated liquid phenol can be used topically as a local anesthetic for otology procedures, such as myringotomy and tympanotomy tube placement, as an alternative to general anesthesia or other local anesthetics.