Eine neue Art von Strahlen [wrapper title]. Offprint from Sitzungs-Bericht der physikalisch-medicinische Gesellschaft zu Würzburg, no. 9 (1895). [With:] Eine neue Art von Strahlen. II. Mittheilung. Offprint from ibid., nos. 1 & 2 (1896).

Würzburg: Verlag und Druck der Stahel’schen K. Hof- und Universitäts-Buch und Kunsthandlung, 1895 [- 1896].

First editions, first issues, and fine copies, of the rare offprints of Röntgen’s discovery of X-rays, the most important contribution to medical diagnosis in a century, and a key to modern physics. “While performing experiments with a Crookes vacuum tube, a type of cathode-ray tube, Röntgen observed that some agent produced in the tube was causing barium platinocyanide crystals to fluoresce. Upon investigation he found that the fluorescence was caused by unknown rays (which he named ‘X-rays’) originating from the spot where cathode rays hit the glass wall of the vacuum tube. He announced his discovery in the present paper, which described the rays’ photographic properties and their amazing ability to penetrate all substances, even living flesh. Although he was unable to determine the true physical nature of the rays, Röntgen was certain that he had discovered something entirely new, a belief soon confirmed by the work of other scientists such as Becquerel, Laue and the Curies. For his discovery, Röntgen was awarded the Nobel Prize in physics for 1901” (Norman 1841). “Röntgen’s second paper on X-rays reported his latest findings: that X-rays render air conductive (a phenomenon already recognized), and that the target of the rays does not have to be simultaneously the anode of the cathode-ray tube. He described a scale for measuring X-ray intensity, along with other innovations in equipment designed for the optimal production of X-rays” (Norman 1842). “Their importance in surgery, medicine and metallurgy is well known. Incomparably the most important aspect of Röntgen’s experiments, however, is his discovery of matter in a new form, which has completely revolutionized the study of chemistry and physics. Laue and the Braggs have used the X-rays to show us the atomic structure of crystals. Moseley has reconstructed the periodic table of the elements. Becquerel was directly inspired by Röntgen’s results to the investigation that discovered radioactivity. Finally J.J. Thomson enunciated the electron theory as a result of investigating the nature of the X-rays” (PMM). “The discovery by Professor Röntgen of a new kind of radiation from a highly exhausted tube through which an electric discharge is passing has aroused an amount of interest unprecedented in the history of physical science” (J.J. Thomson, ‘On cathode rays,’ Report of the Sixty-sixth Meeting of British Association for the Advancement of Science, 1896). “It was this separate printing [of the first paper], and the following four additional printings in five issues, that were primarily responsible for the rapid dissemination of the news of Röntgen's discovery” (Klickstein, Röntgen, p. 62).

“On Friday evening, 8 November 1895, Wilhelm Röntgen remained long hours in his laboratory and was late for dinner − so the story goes. He had been kept by a most puzzling observation he made while repeating some of Heinrich Hertz’s and Philipp Lenard’s recent experiments on cathode rays.

“His apparatus was very simple and standard; it consisted of a Ruhmkorff spark coil with a mercury interrupter and a Hittorf discharge tube. That evening, in preparing for his next experiment, he had carefully covered the tube with black cardboard and drawn the curtains of the windows. He hoped to be able to detect some fluorescence coming from the tube with a fluorescent screen made of a sheet of paper painted with barium platinocyanide. That screen, which he intended to bring close to the tube later on, was lying on the table at some distance. Röntgen wanted to test the tightness of the black shield around the tube. He operated the switch of the Ruhmkorff spark coil, producing high-voltage pulses of cathode rays and looked for any stray light coming from the glass tube. He then happened to notice out of the corner of his eye a faint glimmer towards the end of his experimentation table. He switched off the coil, the glimmer disappeared. He switched the coil back on, the glimmer reappeared. He repeated the operation several times, the glimmer was still there. He looked for its source and found that it came from the fluorescent screen.

“In the interview he granted in March 1896 to H. J. Dam, a London-based American reporter for the American magazine, McClures, Röntgen was asked: ‘What did you think?’ His answer was: ‘I did not think, I investigated. I assumed that the effect must have come from the tube since its character indicated that it could come from nowhere else’. Röntgen found that the intensity of the fluorescence increased significantly as he brought the screen close to the discharge tube. More baffling, the propagation of this ‘radiation’ was not hampered if he put a piece of cardboard between the screen and the tube, or other objects such as a pack of cards, a thick book or a wooden board two or three centimetres thick. Then he moved the screen farther and farther away, even as far as two metres, and, his eyes being well accustomed to obscurity, he could still see the very faint glimmer. As an added fortunate circumstance, according to H. H. Seliger, Röntgen being colour-blind, his eyes had enhanced sensitivity in the dark.

“After dinner, Röntgen went back down to his laboratory and repeated his experiment, now putting various sheets of materials such as aluminium, copper, lead or platinum in front of the screen. Only lead and platinum absorbed the radiation completely, and lead glass was found to be more absorbing than ordinary glass. Röntgen held a small lead disk in front of the screen and was very surprised to see not only the shadow of the disk, but also the shadow of the bones of his own hand! He also found that photographic plates were sensitive to this unknown radiation.

“In the days that followed, Röntgen told no one of his startling observations, neither his assistants nor his wife. He was morose and abstracted, according to his wife, and often ate and even slept in his laboratory. The discovery was so astounding, so unbelievable, that he would not disclose it before he had fully convinced himself of its reality by repeated observations and had determined the properties of this new radiation.

“In the same interview for McClures Magazine mentioned above, he said: ‘It seemed at first a new kind of light. It was clearly something new, something unrecorded’. ‘Is it light?’ ‘No, it can neither be reflected nor refracted.’ ‘Is it electricity?’ ‘Not in any form known’. ‘What is it?’ ‘I do not know. Having discovered the existence of a new kind of rays, I of course began to investigate what they could do’. Indeed, being a careful experimenter, he made in the following seven weeks very systematic studies of the properties of the new rays, X-Strahlen, as he called them. During all that period, he remained uncommunicative, but, shortly before Christmas, he invited his wife to his laboratory and showed her his work. He even took a radiograph of her hand. The results of his investigations are recorded in the preliminary report he handed to the president of the Würzburg Physikalisch-medicinische Gesellschaft on 28 December [the offered paper]. On account of its outstanding importance, the President of the Society agreed that the report should be printed at once, even though it had not been presented orally at a meeting …

“Rontgen's first communication, written in a precise and matter-of-fact way, reveals what a thorough and meticulous investigation he made of the properties of the new rays.

  1. Many other bodies besides barium platinocyanide exhibit fluorescence when submitted to the action of X-rays: calcium sulphide, uranium glass, Iceland spar, rock-salt, etc.
  2. X-rays pass through all bodies, as shown by Lenard for cathode rays. Röntgen compared the attenuation of X-rays through various materials. For instance, the radiographs of a hand showed that bones were more absorbing than flesh. Generally speaking, the absorption of X-rays increases with the density and the thickness of the bodies. Rontgen made quantitative estimates and found roughly the same attenuation for metallic foils of platinum, lead, zinc, and aluminium, 0.018 mm, 0.050 mm, 0.100 mm, and 3.500 mm thick, respectively. He also checked the increase of absorption with thickness by means of photographs taken through tin foils of gradually increasing thicknesses.
  3. X-rays are not deflected by a prism. Röntgen used water and carbon disulphide in mica prisms of 30°, and prisms of ebonite and aluminium, but found no effect. There was no refraction by lenses either, and this ‘shows that the velocity of X-rays is the same in all bodies’.
  4. X-rays are diffused by turbid media, like light. Likewise, no conclusive reflection of X-rays by a mirror was observed. After these negative observations, Röntgen thought that maybe, nevertheless, ‘the geometrical arrangement of the molecules might affect the action of a body upon the X-rays for instance according to the orientation of the surface of an Iceland spar plate with respect to its [optical] axis’, but the experiments with quartz and Iceland spar on this point also lead to a negative result.
  5. Despite all his efforts, Röntgen could not find any interference effects. He attributed this negative result to the very feeble intensity of the X-rays. Laue noted that he was right in this, since, having shone X-rays on quartz and calcite crystals, he would have observed interference fringes if the intensity had been higher. But Röntgen told him that in any case he would never have imagined interference effects to be like those seen by Friedrich and Knipping!
  6. X-rays are much less absorbed than cathode rays, and unlike them, are not deflected by magnets. They are a different kind of radiation.
  7. The intensity of the rays decreases as the inverse square of the distance between the discharge tube and the screen.
  8. X-rays cast regular shadows, as shown by many photographs of shadows of various objects, as well as by pinhole photographs. This indicates a rectilinear propagation, hence the term ‘rays’.

“In conclusion, Röntgen noted that ‘a kind of relationship between the new rays and light appears to exist’ and suggested tentatively ‘Should not the new rays be ascribed to longitudinal waves in the aether?’

“There were no illustrations in the report, but Röntgen made copies of nine of the most important radiographs, such as a set of weights in a closed wooden box, a piece of metal whose lack of homogeneity was revealed by the X-rays, and a wooden door with lead paint, the most striking and extraordinary one being, of course, the radiograph of a hand showing the bones. He mailed them on New Year’s Day 1896, together with preprints of his paper, to ninety leading physicists in Germany, Austria, France, and England. One of the recipients was F. Exner, the Director of the Institute of Physics at Vienna University, whom he knew from his younger days at the Polytechnic Institute in Zürich. Professor Exner showed the report and the photographs to some friends, among whom was E. Larcher. Larcher’s father happened to be the editor of the journal Die Presse in Vienna. As a good journalist, he immediately felt the importance of Röntgen’s discovery and wrote without waiting an article which made the front page of that journal on Sunday, 5 January 1896, under the headline ‘Eine sensationelle Entdeckung’ (a sensational discovery). This was indeed sensational news. They were cabled immediately by foreign correspondents to their home journals, and, from then on, they spread round the world with the speed of lightning. The discovery was reported next day in the dailies, on 6 January in the Frankfurter Zeitung and in the London Daily Chronicle, on the 7th in the Standard, on the 13th in the Paris Le Matin, on the 16th in the New York Times, and on the 31st in the Sydney Telegvaph. The professional journals followed suit immediately, the Electrical Engineer, New York, on 8 January, under the title ‘Electrical photography through solid matter’, the Electrician, London, on the 10th, the Lancet, London, on the 11th, and the British Journal of Medicine on the 18th, with a note by the English physicist, A. Schuster, one of the recipients of Röntgen’s mailings. It was announced at the French Academy of Sciences on 20 January. An English translation of Röntgen's communication was published in Nature, London, on 23 January, along with short articles by A. A. Campbell Swinton and A. Schuster, and in Science (USA) on 14 February. A French translation appeared in L’Eclairage electrique on 8 February. The imagination of the general public was naturally inflamed and it is no surprise, in that Victorian age, that some advertisements appeared for ‘X-ray proof underclothing − especially for the sensitive woman’ …

“In the two months that followed his first communication, Rontgen worked very hard to continue the study of the properties of X-rays, not letting himself be distracted by all the honors which were bestowed on him and the many unwelcome visitors. During that period, he concentrated on two points, which had been briefly mentioned in the first report, and which are described in his second communication:

  1. The first point is the property of X-rays to discharge electrified bodies. In order to be able to observe this phenomenon in a space that is completely protected. He ‘had a chamber made of zinc plates soldered together, which was airtight and large enough to contain himself and his apparatus.’ He found that ‘electrified bodies in air, charged positively or negatively, conductors or insulators, are discharged when X-rays fall on them.’ With his customary meticulousness he detailed the conditions under which this property appears, and recognized that it is due to a change in the air, namely air is ionized by the passage of X-rays. He recognized the effect, but did not name it.
  2. The second point was that X-rays could be produced in many materials other than glass, for instance if the beam of cathode rays fell on a plate of aluminium or platinum. Röntgen found that the greatest intensity was obtained with platinum. For that he used ‘a discharge apparatus in which the cathode is a concave mirror of aluminium and the anode a plate of platinum at the centre of curvature of the mirror,’ a usual set up at the time” (Authier, Early Days of X-ray Crystallography, pp. 52-60).

After holidaying in Italy with his wife in March 1896, Röntgen continued his study of the properties of X-rays, recording his observations in his third communication, ‘Weitere Beobachtungen über die Eigenschaften der X-Strahlen. Dritte Mittheilung’ (published in 1897 in the Sitzungsberichte der Königlich Preussischen Akademie der Wissenschaften zu Berlin). He showed that any matter, when submitted to X-rays, itself emits X-rays, and that a body hit by cathode rays emits X-rays equally in all directions; he further investigated the transparency of various substances to X-rays; and he failed to demonstrate diffraction of X-rays.

“Röntgen was showered with honours, invitations, and prizes, the most prestigious one being the very first Nobel Prize in Physics, awarded in 1901, but, being shy of nature, he declined many other invitations to speak again in public. He did not even give a lecture after receiving his Nobel Prize. The Prince Regent of Bavaria bestowed on him the Royal Bavarian Order of the Crown, which entitled the recipient to be called von. Rontgen accepted the decoration, but declined the nobility. He did not take any patent, and gave his discovery to the world without deriving any personal profit from it” (ibid., p. 59).

There were five separate printings, in six issues, of the offprint of the first communication in the space of two months. The first issue offered here has wrappers but no title page and is dated ‘Ende 1895.’ No offprints of the third communication are known. Röntgen published no further work on X-rays after these three communications.

Two vols., 8vo. I. pp. 10, [2, blank]. II. pp. [1-3], 4-9, [3, publisher’s advertisements]. Original buff (I) and orange (II) printed wrappers (two light vertical creases on I where folded for posting). Signature of F.W. Stevens, Göttingen, on front wrapper of I (possibly the chemist who later worked at the National Bureau of Standards (US)).

Item #4792

Price: $15,000.00

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