Siemens Halske

From 1904 to 1910 C. W. Bailee (7, 18, 55) analyzed many niobium and tantalum compounds and determined the atomic weights of both metals. In 1906 Werner von Bolton of the Siemens Halske Company... 

Uebermikroskopie , J. Springer, Berlin(1940) (Reproduced by Edwards Bros, Ann Arbor, Mich) 7) Siemens Halske AG, Das Uebermikroskop als Forschungsmittel ,... 

Commercial development of beryllium in the United States was begun in 1916 by Hugh S. Cooper with the production of the first significant metallic beryllium ingot. This was followed by formation of the Brush Laboratories Company, which started its development work under the direction of Dr. C.B. Sawyer in 1921. In Germany, the Siemens-Halske Konzein began commercial development work in 1923. 

The accuracy of the measurement has been enhanced by the application of compensators . The principle of compensators was elaborated by Feussner in 1890 [iii]. The compensators worked with two or more identical series of resistances, sometimes combined with a - Wheatstone-bridge and a Thomson-bridge. Many variants such as Franke-, Wilsmore-, Raps- or Siemens-Halske-, Lindeck-Rothe- etc. compensators were used. 

Siemens-Halske cell — This was a variant of the Daniell cell. See also -> zinc, -> Zn2+/Zn electrodes, Zn2+/Zn(Hg) electrodes, -> zinc-air batteries (cell), and Leclanche cell. 

This value may be determined by means of a test set as discussed above. Thus the method, which has been employed by Siemens Halske and by Weston, is of great value for precision work with a galvanometric indicator. The principal objection to it, which applies to all galvanometric indicators so far described when used for accurate measurements is the necessity of measuring the resistance of the line and couple, this latter measurement requiring the use of a test set or similar device. This objection is eliminated in the following instrument, and other desirable features have been added. 

In 1906 Werner von Bolton at Siemens Halske in Germany manufactured niobium by the aluminothermic method and purified it by repeated re-melting in a vacuum furnace. 

The first ductile tantalum was manufactured by W. von Bolton at Siemens Halske in Germany in 1903 and was used for metal wire in electric light bulbs. Many milHons of tantalum wire lamps were produced until the metal tungsten replaced it Tungsten is less volatile at the high working temperature and is thus more suitable. 

Walter Noddack and Ida Tacke (Mn and Mrs. Noddack) started systematic experimental attempts to find elements 43 and 75 in 1922. They worked partly at the physical-chemical institution at the University of Berlin, partly at the Physico-Technical Testing Institute (Physikahsch-Technische Reichsanstalt). Otto Berg at Siemens Halske took part in the work as an expert on spectroscopic investigations. 

With renewed support from Notgemeinschaji, Walter and Ida Noddack could take home a considerable quantity of molybdenum ore from Norway. Its rhenium content was 2-4 mg per kg. The ore was treated at the tantalum factory of Siemens Halske, and the one gram goal agreed upon was reached in the summer 1929. The Noddacks now possessed the large rhenium quantity of 3 g. 

The Transmission Electron Microscope (TEM) was the first type of electron microscope to be developed and is patterned exactly on the Light Transmission Microscope, except that a focused beam of electrons is used instead of light to see through the specimen. It was developed by Max Knoll and Ernst Ruska in Germany in 1932, 35 years after J. J. Thompson s discovery of the electron. The technique quickly surpassed the resolution of optical microscopy, and in 1938 the first commercial instruments began to be produced by the Siemens-Halske Company in Berlin [85]. 

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