Dental radiology / by Francis Le Roy Satterlee, jr.

  • Satterlee, Francis Le Roy.
Date:
[1913], [©1913]
Catalogue details

Licence: Public Domain Mark

Credit: Dental radiology / by Francis Le Roy Satterlee, jr. Source: Wellcome Collection.

Provider: This material has been provided by the Augustus C. Long Health Sciences Library at Columbia University and Columbia University Libraries/Information Services, through the Medical Heritage Library. The original may be consulted at the the Augustus C. Long Health Sciences Library at Columbia University and Columbia University.

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    CHAPTER I. Early Investigations and Discovery of the X Ray y ]\Iichael Faraday was the pioneer investigator of electrical currents and vacuum tubes. As early as 1838 he conducted a series of experiments with an electrical discharge through rari- fied gases, and invented the terms 'anodg^ and 'cathode' for positive and negative electrodes. His researches are now his- torical, inasmuch as they opened up a new field of investigation that was in time to bear fruit in the marvelous, though acci- dental, discovery of the X Ray. Faraday was followed some time later by Gassiott, whose ideas were afterward carried out by Geissler, of Bonn, the first to construct the tubes that now bear his name. Up to this time the investigations proved but little of importance, beyond the fact that any rarified gas gave ofif a peculiar glow, or phosphorescence, when subjected to an electrical discharge of high potential. This phenomenon became known as 'fluorescence.' Air produced a pale violet glow, hydrogen a red, and carbon dioxide a steel-blue shimmer. T-j Professor Hittorf, the celebrated electrical physicist, of Munster, next experimented with a Geissler tube of higher degree of exhaustion. He noticed an increasing resistance of the electrical current to the coefficient of rarification, he also found that the color of the gases under fluorescence varied with this increased degree of rarification and that the glow proceeded in straight lines from the negative electrode, casting a shadow of an interposed object upon the wall of the tube, and he furthermore disclosed the fact that these rays were capable of deflection by a magnet. Doctor Crooks, afterward Sir William, was the next inves- tigator to enter the field of research, and in 1878 made some