The Roentgen rays in medicine and surgery as an aid in diagnosis and as a therapeutic agent : designated for the use of practitioners and students / by Francis H. Williams.

  • Williams, Francis H. (Francis Henry), 1852-1936.
Date:
1903
Catalogue details

Licence: In copyright

Credit: The Roentgen rays in medicine and surgery as an aid in diagnosis and as a therapeutic agent : designated for the use of practitioners and students / by Francis H. Williams. Source: Wellcome Collection.

Provider: This material has been provided by The University of Leeds Library. The original may be consulted at The University of Leeds Library.

    52/802 (page 14)
    Speed Controller. — The speed of the plates may be varied from 50 to 250 revolutions per minute by means of the speed controller, which determines the speed of the motor, and thus a greater or less amount of energy may be obtained. Leakage of Electricity. — During damp weather the leakage of the electricity from the static machine is greater, and a smaller amount is generated, than in dry weather; therefore, the machine must be large enough to give out a sufficient amount of electricity even when the air is moist, otherwise the practitioner is at the mercy of atmospheric con- ditions. A simple way of ascertaining the amount of electricity avail- able for use is to look at the brush discharge above the collecting combs; when this is wide the amount is greater than when it is narrow. Precautions against Moisture.— 1. Case. If the plates are kept warm and dry they can be depended upon to do good work, no matter what the weather may be. Therefore, the machine must be provided with a case. The case of my machine is 244 centimetres long, 228 centimetres high, and 90 centimetres wide. A case should be of this size, at least, for plates of the dimensions described. The shaft of my machine might well be 5 centimetres or more longer than that shown in the drawing, so that if desired the case could be put a little farther from the machine, as by this means the latter could be surrounded by a thicker layer of air, and therefore the leakage of electricity would be diminished. The case is made of pine doors, that can be ordered at a factory, of any size desired. These doors make an inexpensive and good case. The interior and exterior of the case is varnished to give it a surface that will not absorb or give out moisture. 2. Removal of Dampness from Plates. — Some method, also, must be adopted for removing the dampness from the plates. There are various ways of accomplishing this object. Chloride of calcium, for instance, and other forms of drying material may be used, placed in a dish inside the case, but I have found them insufficient in themselves to take the moisture from the plates; moreover, if chloride of calcium is employed, there is the risk that fine particles of it will fall upon the plates and thus coat them with a covering that absorbs moisture. It is evident, therefore, that this method of getting rid of the moisture is not altogether satisfactory. The most convenient and efficient method is the use of some form of heater, such as an electric heater. The heaters, one placed at either end of the case, warm the air in the case,