Dental Electro-therapeutics

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Lea & Febiger, 1918 - Electricity in dentistry - 320 pages
 

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Page 26 - The position of the two pairs of brushes with respect to the fixed collecting combs and to one another is variable, as each pair is capable of being rotated on the spindle through a certain angle, and there is one position of maximum efficiency. This position in the machine appears to be when the brushes touch the disks on diameters situated about 75 from the collecting combs, and 30 from one another.
Page 39 - ... bottle containing alcohol. A thermometer t was passed through a hole in the insulating stopper of the bottle. The resistance of the fine wire was known, and the observations consisted in measuring the current and noting the rise of temperature. Joule found that the number of units of heat generated in a conductor is proportional — (1) To its resistance. (2) To the square of the strength of the current. (3) To the length of time the current flows. 234. The Heat Equivalent of a Current. — Let...
Page 37 - The strength of the current in any circuit or part of a circuit varies directly as the electromotive force in that circuit and inversely as the resistance of the circuit.
Page 25 - Holtz that it is self exciting, and its polarity will not reverse under ordinary circumstances while it is in action. It consists of two circular glass discs (or any even number up to twelve), mounted in pairs upon a fixed horizontal spindle in such a way that they rotate in opposite directions at a distance apart of not more than oneeighth of an inch. Each disc is attached to the end of a hollow boss of wood, or of metal, upon which is turned a small pulley. The pulleys are driven by a cord or belt...
Page 246 - ... drug administered by the mouth or subcutaneously and the same administered by electrolysis. Thus a solution of cocaine injected subcutaneously produces quite different effects to that introduced by electrolysis. By the latter method it produces anaesthesia but does not diffuse, and the anaesthesia remains strictly limited to the surface covered by the electrode. It would appear that the ion is never introduced into the genera] circulation but into the cell plasma.
Page 25 - ... while it is in action. It consists of two circular glass discs (or any even number up to twelve), mounted in pairs upon a fixed horizontal spindle in such a way that they rotate in opposite directions at a distance apart of not more than oneeighth of an inch. Each disc is attached to the end of a hollow boss of wood, or of metal, upon which is turned a small pulley. The pulleys are driven by a cord or belt from larger pulleys attached to a spindle below the machine, and rotated by a winch handle...
Page 36 - ... course, directly as the length, and inversely as the square of the diameter, of the wire. As the current strength in any circuit is the same in all parts, or at all points, of that circuit, the electro-magnetic field developed by any...
Page 25 - Both discs are well varnished, and attached to the outer surface of each there are radial sector-shaped plates of tin-foil or thin brass disposed around the discs at equal angular distances. These sectors are not essential to the action of the machine, but they make it more easily self-exciting. Twice in each revolution the two sectors situated on the same diameter of each...
Page 26 - ... just grazing the tips of the brushes as they pass them. The position of the two pairs of brushes with respect to the fixed collecting combs and to one another is variable, as each pair is capable of being rotated...
Page 30 - The difference of potential between any two metals is equal to the sum of the differences of potentials...

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