A very important relation between the atomic number of an element and its X-ray spectrum was discovered by the brilliant young English physicist, H. G. T. Moseley (1888-1915), in his 26th year, a year before his death by a Turkish bullet at the Dardanelles. While analyzing the characteristic X-rays which are given off when any kind of substance is bombarded with cathode rays, Moseley found that the atoms of all the different substances emit radiations or groups of radiations which are extraordinarily similar, but which differ in their wave lengths as we proceed from substance to substance; the frequencies (wave lengths) change by definite steps as one progresses from elements of lower to elements of higher atomic weights. Through Moseley’s epoch-making discovery we now know that each of the 92 elements, from hydrogen to uranium, is built up by successive additions of one positive charge (proton) and one negative electron, and that the atomic numbers—from 1 to 92—correspond to the number of protons and electrons in each successively heavier (and more complex) atom.
FOOTNOTES:
[1] This phase of our subject can only be alluded to in this little book. For an authoritative yet easily understood exposition of the subject, see Bragg, W. H. and W. L., “X-Rays and Crystal Structure”; also Kaye, G. W. C., “X-Rays”; and, for more advanced reading, deBroglie, Maurice, “X-Rays”.
CHAPTER II
CURATIVE VALUE OF X-RAYS
In my Little Blue Book on Radium (No. 1000), it is shown that the “emanation” and the “gamma rays” of radioactive substances are being used to great advantage in our hospitals, but that certain dangers to the patient’s normal cells attended employment of these radiations.
It is gratifying to note that successful X-ray treatments are now being given in cases of cancer, rays being produced—under high-tension currents—that are almost identical with the gamma rays of radium.
Moreover, the X-rays have a double value in medicine. In the first place, they are used as an aid to diagnosis, forming those branches of radiotherapy known as radioscopy and radiography. Then they are also used to great advantage in the alleviation or cure of certain maladies. By means of radioscopic or radiographic examination it may be found that there is a tumor in the chest, and as a result of that diagnosis it may be decided to institute treatment (radiotherapy) by means of X-rays or radium rays or the two combined.
The method of employing extremely penetrating X-rays—under high voltage and amperage—seems to have been first used in Germany, during the World War, but was soon developed to a high degree of efficiency in France, England, and the United States, especially by Dr. William Duane, professor of biophysics at Harvard.
As early as 1919, Professor Dessauer, in Germany, produced the penetrating X-rays by means of a high-tension current ranging from 170,000 to 240,000 volts. It was later found, that rays at 200,000 volts became homogeneous, so that a further increase was considered as of no therapeutic value.
In March, 1923, Dr. I. Seth Hirsch, head of the X-ray department of the Bellevue Hospital in New York, gave a drastic treatment—for cancer—of four periods of 16 hours each with the X-rays at 250,000 volts, apparently with satisfactory results. The patient suffered no pain or inconvenience during the treatment with the exception of occasional nausea. A year later an experiment was made in a Philadelphia laboratory where an X-ray treatment of 300,000 volts was used. It seems that alleviation rather than cure has been the result of nearly all cases where cancer had been well advanced.