File:A manual of practical medical electricity - the Röntgen rays and Finsen light (1902) (14760656226).jpg

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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und in exactly the samecondition, and even at the end of a year all that it willprobably require will be a little water. To medical men,this is of paramount importance. Attempts have been made to lower the internal resist-ance of the Leclanche cell by dispensing with the porouspot. In the agglomerate form, the carbon element andthe peroxide of manganese are consolidated together bygreat pressure, after addition of some resinous material,and the porous pot is not required. Mr. Schall places the zinc inside an agglomerate cylinderof carbon (Fig. 15); this materially reduces the internalresistance (often under one ohm). The zinc is preventedfrom touching the carbon at its lower extremity by an 3—2 36 A Manual of Practical Medical Electricity indiarubber ring, and it is supported above by a disc ofwood or a rubber cork, which fits the mouth of the cellpretty closely, and tends to lessen evaporation and thecreeping over of the salts. The Leclanche cell is probably the best one at present
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Fig. 15.—Leclanche of Low Internal Resistance. known for furnishing a galvanic current for medical treat-ment . Its advantages are : 1. It requires scarcely any looking after. 2. It will last with fair use for an indefinite period. 3. It does not deteriorate through inactivity. 4. Though it polarizes rapidly on short circuit, yetit will yield during ordinary galvanization a practicallyconstant current for from ten to twenty minutes. 5. It is cleanly, and it yields no fumes. Forms of Primary Cells 37 It is better in charging the cell to dissolve the sal-ammoniac (which should be pure) in warm water in a jug,and to half fill the cell with it when it is cold. The solu-tion may be made of any strength, from half saturationto saturation; the weaker it is, the less tendency thereis for the salts to creep over the sides of the jar. In filling the cells, care should be taken not to moistenthe sides of the jar with the solution, and it is well to coatthe upper margins of the sides with vasel

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