The Röntgen rays in medical work (1899) (14570211280)

Identifier: rntgenraysinmedi00wals (find matches)

Title: The Röntgen rays in medical work

Year: 1899 (1890s)

Authors: Walsh, David

Subjects: X-rays Radiography X-Rays Radiography

Publisher: London : Baillière, Tindall and Cox

Contributing Library: Francis A. Countway Library of Medicine

Digitizing Sponsor: Open Knowledge Commons and Harvard Medical School

Text Appearing Before Image:

ersa. The top screw regulates the amount of current,and the lower the speed. The Vril Contact-breaker is a modification of the foregoing.It was devised by Mr. J. King, A.M.I.C.B., and is made byW. Watson and Sons. It will be seen from Fig. 12 that the ironhammer is mounted as usual, and the platinum contact carriedby an intermediate spring, B. 3—2 34 THE RONTGEN RA YS IN MEDICAL WORK The action consists of the attraction of the hammer, by themagnet, to the coil, causing the point of screw D to impinge onthe top of the spring B, so causing a separation of the platinumpoints, F. The advantages claimed for this system are that aprolonged contact is afforded, giving time for the thoroughmagnetic saturation of the core ; that in consequence much lessbattery power is required than with ordinary patterns ; aud thatthe liability to heating of the platinum contacts is greatlydiminished, while ■ sticking is almost impossible. This is anexcellent break, capable of a wide range of adjustment.

Text Appearing After Image:

Fig. 13.—Electeo-Magnetic Beeak. Some of the best Eontgen ray workers keep to the top contactspring break, and produce excellent results therewith. On theother hand, many prefer a mercury break, or a mechanical formdriven by a motor. With a rapid mercurial break there canbe little doubt that a more constant fluorescence can be excitedupon the screen. It is claimed by some observers that it pro-duces better photographic results in dealing with deep-seatedtissues. There are many excellent forms of mercurial breaksupon the market, perhaps one of the best being that made byMax Kohl, of Chemnitz. Contact is made by metallic rods thatare made to dip alternately into cups containing mercury by the ELECTRICAL APPARATUS AND METHODS 35 action of a rotary interrupter, which is driven by a separatebattery. The rate of breaking can be regulated at will, and isrecorded by a speed-indicator (tachometer). The inventor con-siders from 1,300 to 1,600 interruptions per minute a good averagefor photogr

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1899

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