A manual of practical medical electricity - the Röntgen rays and Finsen light (1902) (14803562003)

Identifier: manualofpractica00turn (find matches)
Title: A manual of practical medical electricity : the Röntgen rays and Finsen light
Year: 1902 (1900s)
Authors: Turner, Dawson
Subjects: X-Rays Electrophysiology Electrosurgery Electric Stimulation Therapy Electrotherapeutics X-rays Electrophysiology Electrosurgery
Publisher: New York : William Wood & Company
Contributing Library: Francis A. Countway Library of Medicine
Digitizing Sponsor: Open Knowledge Commons and Harvard Medical School



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at thisis a more powerful and efficient means of exciting X-raytubes than any other. Professor Trowbridges methodof working the tube directly from a battery of 15,000accumulators through a large resistance is the idealmethod. An electrical machine can be used instead of a coil toproduce the electrical discharges. Of these, the Wims-hurst is perhaps the best. It will be found better notto connect the terminals of the vacuum tube directly tothe prime conductors of the machine, but to allow a smallspark gap to intervene on either side. The size of thesegaps must be varied until the best effects are produced ;if a continuous discharge be desired, the Leyden jars ofthe machine should be disconnected. If this be not done, 21 322 A Manual of Practical Medical Electricity powerful discharges at intervals will be yielded ; theseare very tiring to the eye in fluorescent screen work. Thestatic machine current, being very small, does not heatand so alter the resistance of the tube so much ; it is
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Fig. 139.—Resistance for Working Coils from Mains. more suitable for screen work than for photography. Adisadvantage of the electrical machine is that, unless amotor be employed, an assistant is required to rotate it ;its working is also affected by the weather, its behaviourbeing capricious in this respect, so that, on the whole, it RoNTGEN X Rays 323 is not nearly so efficient or convenient an instrument forproducing the X radiation as a good induction coil. The vacuum tube should be a focus one ; this is a bulbof glass, into either end of which platinum wires are sealed.To the extremity of one of the wires, the anode, a smallflat piece of platinum is attached, inclined at an angle of45° ; to the extremit^^ of the other, the kathode, a concavedisc of aluminium is fastened, at such a distance fromthe anode that the kathode rays are focussed upon it.Platinum wires are chosen to pass through the glass,because platinum and glass have nearly the same co-efficient of expansion under al