A manual of practical medical electricity - the Röntgen rays and Finsen light (1902) (14597004670)

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

Text Appearing Before Image:

Fig. 143.—Wehnelt Interrupter. (Fig. 145). Believing that a rubbing contact between solidsgives a better contact, and a much cleaner and moresudden break than any contact and break between a solidand a liquid, I have endeavoured, in the following manner,to get over the difficulties that presented themselves.The chief difficulty to be overcome is the burning awayof the surfaces at the point where the current is broken.This can be diminished by immersing the separating RoNTGEi^ X Rays 331 surfaces in alcohol or petroleum, but it cannot be entirelyprevented, and a deep pit or groove is soon eaten out ofthe contact pieces. The pitting can also be diminishedby employing platinum or iridium surfaces, but the objec-tion to this is the great expense of these materials. A

Text Appearing After Image:

Fig. 144.—Wehnelt Discharge. fixed contact breaker, then, cannot be used for any lengthof time. I next tried a roller, and found that so long as itwas rotated so as to cause it to continually present afresh separating surface, it wore away evenly all round,and that it could thus be employed for an indefinite 332 A Manual of Practical Medical Electricity length of time. I now made both the contact pieces ofmetal rollers, held together by a spring, and I arrangeda lifting cam in such a way that while it separated therollers, it also caused them to rotate, for this latter point

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1902

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