MISCELLANEOUS RESEARCHES ON ROENTGEN RAYS.
-------
151. PUPIN AND SWINTON’S EXPERIMENT. SCIAGRAPHIC PLATES COMBINED WITH
FLUORESCENT SALTS. _The Elect._, Lon., Apr. 24, ’96.—Prof. Pupin, of
Columbia College (_Electricity_, N.Y., Feb. 12, ’96—the author saw him
use it Feb. 7, ’96—), was among the first, and probably actually the
first, to lessen the time of exposure by a fluorescent screen. Prof.
Salvioni also worked in this direction at an early date. Prof. Swinton
reported some details in the matter, and he was able to obtain a
sciagraph of the bones of the hand in less than 10 seconds, with a
moderately excited discharge tube, whereas, without the screen the time
was two minutes. He experimented first with barium platino cyanide, but
the results referred to were obtained with calcic tungstate, finely
ground, and made up into paste by means of gum, and dried. He spread the
same upon a celluloid sheet which was placed with the celluloid side
against the photographic film. The difficulty experienced first was in
the formation of spots on the negative, because some of the crystals
fluoresced more than others. Such a defect, however, showed that the
fluorescent salt increased the rapidity of the action upon the
photographic film. The result of this experiment, as well as that of
others, has sufficiently established the fact that the fluorescent
screen is of great importance in connection with the art of rapid
sciagraphy.
Phosphor sulphide of zinc is among those which hasten photographic
action. (Chas. Henry, in _Comptes Rendus_, Feb. 10, ’96.) Dr. W. J.
Morton employed the screen in taking the sciagraph of the thorax, p. 61.
The advantageous use is also confirmed by BASILEWSKI (_Comptes Rendus_,
March 23, ’96. From trans. by Louis M. Pignolet).—The photographic plate
was covered with a sheet of paper coated with barium and platino
cyanide, so that the two prepared surfaces were in contact, and the
fluorescent paper was between the object and the plate.
[Illustration:
THORAX. § 206.
By W. J. Morton, M.D. Fluorescent screen used (§ 151).
]
[Illustration:
NORMAL ELBOW. § 204.
By Prof. Miller.
]
J. W. Gifford, (_Nature_, May 21, ’96) tried a great variety of
fluorescent bodies in combination with the photographic plate, and found
that potassium platino cyanide was decidedly the best.
152. THOMPSON’S (S. P.) EXPERIMENT. PENETRATING POWER OF X-RAYS VARIES
WITH THE VACUUM. _Comptes Rendus._ CXIII., p. 809. _The Elect._, Lon.,
April 24, ’96, p. 866. In a communication to the Académie des Sciences
Prof. Sylvanus P. Thompson of the University College of Liverpool,
argued that by one kind of X-rays the bones of the hand were more easily
penetrated than by another kind. The two varieties were produced by
different vacua. § 75 and 76. Let the vacuum be supposed to become
higher and higher. At the first generation of the X-rays, the
fluorescent screen showed that the bones of the hand cast very dark
shadows. With increase of the vacuum, the shadows of the bones were very
faint. This result is also obtained by reduction of temperature. §
152_a_.
152_a_. BLEEKRODE’S EXPERIMENT. PERMEABILITY AT LOW TEMPERATURES
INCREASED. _Elect. Rev._, Lon., June 12, ’96.—Experiments performed by
him confirmed those of Edison. § 135. An experiment by Prof. Dewar
strongly confirmed the results. They noticed the same peculiarity that
Edison did, namely, that the shadow of the finger exhibited the flesh
and bones as if they were equally transparent. Varied tests showed that
the reduction of the temperature of glass increased its permeability.
153. MURRAY’S EXPERIMENT. REDUCTION OF THE CONTACT POTENTIAL OF METALS
BY X-RAYS. _Trans. R. So._, Mar. 19, ’96. _The Elect._, Lon., Apr. 24,
’96, p. 857. J. R. E. Murray of the Cavendish Laboratory, at the
suggestion of Prof. J. J. Thomson, carried on a long series of careful
experiments, to find whether the contact potential of a pair of plates
of different metals was, in any way, affected by the passage of X-rays
between the plates. All the ordinary precautions were taken. The contact
potential was measured by Thomson’s (Kelvin) method, see _Trans. Brit.
Asso._, 1880. The important result obtained, was that “the air through
which the rays pass, § 90, is temporarily converted into an electrolyte,
§ 47, and when in this condition forms a connection between the plates,
which has the same properties as a drop of acidulated water, namely, it
rapidly reduces the potential between the opposing surfaces of the
plates to zero, and may even reverse it to a small extent.”
154. NODON’S EXPERIMENT. TRANSPARENCY OF DIFFERENTLY COLORED MEDIA TO
THE X-RAYS. _Comptes Rendus_, Feb. 3, ’96. From trans. by Louis M.
Pignolet. The rays were passed through two openings in a thick metal
diaphragm, one of which was covered by an uncolored piece of gelatine
and the other by a piece tinted with the color to be tested. The two
images were received on the same plate. The various colors tested were
traversed with equal facility by the rays, § 68 and 82.
The investigation described above was made by Albert Nodon at the
Laboratoire des Recherches Physiques à la Sorbonne.
This agrees with Bleunard who found that colors seemed to have no
influence on the passage of the rays as water colored with various
aniline colors offered no more resistance than when pure. From trans. by
L. M. P. _Comptes Rendus_, March, ’96.
A. and L. Lumière (_Comptes Rendus_, Feb. 17, ’96,) observed that the
X-rays act in the same manner upon colored photographic plates rendered
sensitive to various regions of the spectrum. Thus, plates sensitive to
red, yellow and green gave exactly the same impression, provided they
had the same general sensibility to white light. While this may not be
accurately so, it illustrates that materials are penetrated by X-rays
independently of the laws of color.
155. MESLANS. CHLORINE, IODINE, SULPHUR, PHOSPHORUS, COMBINED WITH
CERTAIN COMPOUNDS, INCREASE OPACITY TO THE X-RAYS (_Comptes Rendus_,
Feb. 10, ’96. From trans. by Louis M. Pignolet.)—Carbon in its various
forms was found to be very transparent, also organic substances
containing, besides carbon, only the gaseous elements hydrogen, oxygen
and nitrogen; but this transparency was far from uniform. Organic
substances,—ethers, acids, nitrogenized compounds (_corps azotes_),—were
easily traversed by the rays; but the introduction of an inorganic
element, as particularly, chlorine, sulphur, phosphorus, and, above all,
iodine, renders them opaque. § 82. This occurs also with sulphates of
the alkaloids. Iodoform, the alkaloids, picric acid, fuchsine and urea
are very transparent. Metallic salts are very opaque, but this varies
with the metal and the acid. Bleunard went further into details. The
opacity of solutions of salts increased with the atomic weight of the
metal and of the metalloid. Water was easily traversed by the rays.
Solutions of bromide of potassium, chloride of antimony, bichromate of
potash offered considerable opposition to the passage of the rays.
Solutions of borate of soda, permanganate of potassium were easily
traversed. The liquids were held in paper boxes. The experiments above
related were conducted by Maurice Meslans at l’École de Pharmacie de
Nancy.
[Illustration:
FROM SCIAGRAPH OF PENCIL, KEY, FOUNTAIN-PEN, AND COIN. § 161.
By Prof. McKay, Packer Institute.
]
[Illustration:
FROM SCIAGRAPH BY PROF. MILLER. § 156.
1. Real diamond.
2. Paste.
3. Glass.
4. Real diamond mounted in gold ring.
]
156. BUQUET & GASCARD’S EXPERIMENTS. ACTION OF THE X-RAYS UPON THE
DIAMOND AND ITS IMITATIONS; ALSO UPON JET. _Comptes Rendus_, Feb. 24,
96. From trans. by Louis M. Pignolet.—Sciagraphs taken by the X-rays
showed that diamonds became transparent, and their shadows disappeared
with long exposures; but imitation diamonds remained opaque under the
same conditions. Jet was distinguished from its imitations by the same
method. The diamond and jet cast clearer shadows on a fluorescent screen
than their imitations.
The above tests were made by Albert Buquet and Albert Gascard, at the
Cabinet de Physique de l’École des Sciences de Rouen.
The half-tone on lower half of adjacent page, 164, was taken from a
sciagraph by Prof. Dayton C. Miller, of Case School of Applied Science.
The differences of opacity are proved, because all were of same
thickness and exposed simultaneously.
Prof. Sylvanus P. Thompson (_The Elect._, Lon., May 18, ’96) confirmed
the above, and also found that, although the diamond is more transparent
than glass, it is more opaque than block carbon or graphite.
Mineralogists are thus enabled to submit minerals to the X-ray test in
making analyses.
157. DUFOUR’S EXPERIMENT. INACTIVE DISCHARGE TUBES MADE LUMINOUS BY
X-RAYS. _Comptes Rendus_, Feb. 24, ’96. From trans. by Mr. Pignolet.—He
observed that very small and sensitive Geissler tubes phosphoresced when
exposed to X-rays. § § 22, 23.
158. BEAULARD’S EXPERIMENTS. NON-REFRACTION OF X-RAYS IN A VACUUM.
_Comptes Rendus_, Mar. 30, ’96. From trans. by Louis M. Pignolet. With
prisms of ebonite, F. Beaulard held that no decided deviation could be
observed within the vacuum.
159. CARPENTIER’S EXPERIMENT. SCIAGRAPH SHOWING THE PARTS IN RELIEF ON A
COIN. _Comptes Rendus_, Mar. 2, ’96. From trans. by Louis M. Pignolet.
An imprint of a coin stamped upon a thin piece of well annealed aluminum
by pressing the coin against the aluminum, was reproduced in a
sciagraph. The raised parts of the coin were scarcely 8/100 of a
millimeter high. The aluminum was 5/10 millimeter thick. This result is
admirably represented by the sciagraph of an aluminum medal on page 166,
taken by Prof. Dayton C. Miller, of Case School of Applied Science,
_Elect. World_, N.Y., Mar. 21, ’96, who also made a sciagraph of a
copper plate 1/4 inch thick having blow holes which appeared in the
picture, but they could not be detected by light, serving to illustrate
an application of the new discovery in testing the homogeneity of
metals.
160. WUILLOMENET’S EXPERIMENTS. TRANSPARENCY OF THE EYE TO THE X-RAYS
DETERMINED BY SCIAGRAPH OF BULLET THEREIN. _Comptes Rendus_, Mar. 23,
’96. A sciagraph taken with an exposure of _three hours_ showed
perfectly a lead shot introduced into the vitreous media of the eye of a
full grown rabbit. Therefore the opacity of the media of the eye was not
absolute.
In a second series of experiments by Dr. Wuillomenet a human head was
used, but the results were negative in spite of a great intensity of the
rays and a long exposure, § 82.
161. FERNAND RANWEZ’S EXPERIMENTS. APPLICATION OF THE X-RAYS TO ANALYSIS
OF VEGETABLE MATTER. _Comptes Rendus_, Apr. 13, ’96. From trans. by
Louis M. Pignolet. Sciagraphy can render valuable services in analytical
researches and specially in the analysis of vegetable foods where they
will show the most usual adulterations consisting of mineral substances.
[Illustration:
BAS-RELIEF SCIAGRAPH, § 159, BY PROF. DAYTON C. MILLER.
]
This method offers several advantages for small samples of the
substances can be examined. The samples are not chemically changed. A
great number of tests can be made in a short time. Lastly, the sciagraph
obtained affords a permanent record.
The tests were made on samples of adulterated saffron composed of
mixtures of pure saffron and saffron coated with sulphate of barium. A
sciagraph taken with an exposure of three minutes showed scarcely
visible imprints of the pure but strong impressions of the adulterated.
See sciagraph of pen, (mineral) in holder, (vegetable), in cut at upper
part of p. 164, which also shows the graphite in a wooden pencil.
162. ERRERA’S EXPERIMENT. ACTION OF THE X-RAYS ON PHYCOMYCES. HERTZ
WAVES AND ROENTGEN RAYS NOT IDENTICAL. _Comptes Rendus_, March 30, ’96.
From trans. by Louis M. Pignolet.—_Phycomyces Nitens_, when submitted to
the asymmetrical action of Hertz electric waves, became curved,
according to Hegler. Errera found a Phycomyces was not affected by the
X-rays, thus denoting an absence of Hertz waves in the rays. Credit for
the above result is due to L. Errera, from experiments made at the
Laboratoire Physique and the l’Institut Solvay (Université de
Bruxelles).
163. GOSSART, CHEVALLIER, FOUTANA AND URUANNI’S EXPERIMENT, IN
CONJUNCTION WITH J. R. RYDBERG. NO MECHANICAL ACTION OF X-RAYS. _Comptes
Rendus_, Feb. 10, Mar. 23, Apr. 13, ’96. From trans. by Louis M.
Pignolet.—The former party alleged that radiations from a discharge tube
caused a cessation of the rotation of the vane of the radiometer. J. A.
Rydberg was not inclined to confirm such action. A. Foutana and A.
Uruanni made experiments and concluded that the action was due to an
electro-static force, having noticed that a Leyden jar would also
produce such effect. The author made some experiments to determine the
matter in reference to X-rays at a distance outside of the
electro-static field. The rays would neither stop the vanes nor cause
them to rotate. He made some other experiments to detect whether there
was any direct mechanical power possessed by the rays; but if any, it
was exceedingly feeble.
T. C. Porter made some experiments at Eton College, (_Nature_, June 18,
’96,) which confirmed the above results, finding that the radiometer is
entirely inert to the Roentgen rays, whether they be from a properly
electrically screened hot or cold tube. He distinguished between the
caloric conditions, for he found that, not only will reduction of
temperature vary the penetrating power of the rays, § 135 and 152_a_,
but also will an increase of temperature.
164. BATTELLI’S EXPERIMENT. X-RAYS WITHIN DISCHARGE TUBE. _Nuovo
Cimento_, Apr., ’96, p. 193; _Elect. Rev._, Lon., June 12, ’96.—Shortly
after the announcement of the discoveries of Lenard and Roentgen, it
would have been considered strange to assert that X-rays may exist
inside of the discharge tube. Battelli certainly correctly infers, that
inasmuch as X-rays apparently originate from the point where a material
object is struck by the cathode rays, § 115, it would follow that when
the said object is within the vacuum space, X-rays are propagated before
they reach the glass wall of the discharge tube. It has already been
noted (DeMetz, § 63_a_) that photographic action may be produced within
the discharge tube. Battelli has confirmed this, not by a crude
experiment, like that (failure) of some authority in England, but by a
series of severe tests, leaving no doubt as to the production of
photographic action. He discovered in connection with several
subordinate phenomena that among the rays capable of producing a
photographic impression within the discharge tube, some were deflected
by a magnet and others were not, from which he concluded that X-rays may
exist inside the tube, in conjunction with cathode rays, before
collision with the anti-cathode. The experiment consisted in deflecting
the rays by a magnet, the film being in the path that the rays would
have had without a magnet. There was also a film in the path of the
deflected rays. Photographic action was produced upon both. He varied
the vacuum. Photographic action began at 3-10 mm., had its maximum at
1-70 mm., after which it remained constant. No photographic action was
obtained upon a film placed within the tube opposite the anode, except
in one case where it was exceedingly weak. Lenard continually inferred
that there must be two kinds of cathode rays. § 75. Battelli has
certainly sifted the two rays apart and thus proved Lenard’s
conjectures. § 61_b_, p. 47. _The Elect. Rev._, Lon., pays tribute to
Battelli, by offering the following opinion: “We have no hesitation in
saying that Battelli, by means of interesting and ingenious experiments,
has made the greatest advances in the theory of the X-rays since their
discovery by Roentgen.”
In many cases the author has omitted stating, in taking sciagraphs, that
the films were protected from ordinary light by opaque material. This,
as a matter of course, has always been understood. Battelli also had the
films wrapped in material opaque to ordinary light. Experimenters
should, if possible, always employ aluminum for this purpose, because
the author has always noticed that black paper or cloth permits a great
deal of light to come through, even when in double thickness.
Prof. Sylvanus P. Thompson (_The Electr._, Lon., June 26, ’96) located a
wire in a focus tube in the path of the rays between the platinum
reflector and the wall of the tube. Not only was there a sciagraph of
this wire produced in the sciascope, but also the Crookesian shadow of
the wire on the wall of the bulb. For this experiment the exhaustion
must be quite high. “At no state of exhaustion did the platinum
reflector convert all the internal cathode rays into X-rays.” Both
shadows were cast by the platinum reflector as the origin. More or less
of the rays between the reflector and the glass were sensitive to a
magnet.
[Illustration:
BLEYER’S EXPERIMENT. § 165.
Combined camera and sciascope at the left: and showing induction coil
and discharge-tube at the right.
]
165. BLEYER’S EXPERIMENT. COMBINED CAMERA AND SCIASCOPE. _Elect. Eng._,
July 1, ’96; _Royal Acad. Med. & Sur._, of Naples, Italy.—As early as
April 7, J. Mount Bleyer, M.D., of Naples, constructed and used the
apparatus shown in the adjacent cut, p. 169. The picture is
self-explanatory. Attached to an ordinary camera is a flaring sciascope,
for receiving the temporary sciagraph of the hand, for example. The
X-rays are converted into luminous rays by the fluorescent screen, and,
therefore, the camera will serve to take a picture by means of the
luminous rays from the sciagraph of the hand. The cut represents also an
induction coil and a discharge tube. Soon afterwards, it was reported by
an English paper that Dr. Levy, of Berlin, and others of England, had
also made similar tests with success. In order to illustrate the
applicability of the combination, Dr. Bleyer took many sciagraphs with
the camera. He calls it the photofluoroscope, which, however, will
probably not meet with favor for the name does not suggest the nature of
the instrument. When two radically different devices are combined into
one, it is difficult to formulate an acceptable single word, and,
therefore, the instrument will probably always be called by some of the
following terms: A camera with sciascopic adjustment, or combined
sciascope and camera, or corresponding combinations with the word
fluoroscope.
From the time that Roentgen’s discovery was announced, scientists
throughout the world have made careful experiments, up to date, in all
possible directions, and the time has now come when the number of
experiments is rapidly decreasing, only one or two being noted now and
then in the scientific press, and consisting mostly in repetition, with
occasionally a slight departure, involving a radically new subordinate
discovery; but in view of the great number of scientists, and of their
high standing as careful experimenters, and because also of their desire
to be correct in their inferences, there might seem to be little else to
be investigated. Time only will tell. Before passing to the final
chapters relating to other matters, a few more experiments are related
in the briefest manner.
166. Prof. Sylvanus P. Thompson confirmed non-polarization, (_Phil.
So._, June 12, ’96, and _The Electr._, Lon., June 26, ’96.)
Dr. John Macintyre (_Nature_, June 24, ’96) carried on a long series of
experiments with tourmaline, and also arrived at the conclusion that
polarization of X-rays is practically impossible, § 97, at end.
[Illustration:
FROM SCIAGRAPH BY PROF. GOODSPEED, SHOWING CURVATURE OF THE RADIUS,
DUE TO ARRESTED DEVELOPMENT OF THE ULNA AT ITS DISTAL EPIPHYSIS. ONE
BONE SHOWN THROUGH ANOTHER.
]
167. In the same paper Prof. Thompson showed conclusively that there is
a diffuse reflection of X-rays. § 81 and 103. A curious experiment
consisted in his obtaining dust figures, § 36. by the discharge of an
electrified body by X-rays. In another experiment he caused reflection
of the rays from the surface of sodium located in a vacuum. The amount
reflected was a minimum for normal incidence and increased at oblique
incidence.
168. Prof. Oliver J. Lodge, F.R.S., reported in _The Electr._, Lon.,
June 5, ’96, further detail experiments in the line set out in § 113. He
proved conclusively, as stated by the editorial in _The Electrician_,
that a positive charge has increasing effect upon the ray-emitting power
of the surface exposed to the cathodic radiation.
169. At Eton College, T. C. Porter (_Nature_, June 18, ’96) confirmed
the experiments of others by showing that the blackened face of the
thermopile connected with a very sensitive galvanometer was not
influenced in any manner by X-rays.
170. Prof. William F. Magie, of Princeton, N. J., made a careful
experiment in relation to diffraction. _Princeton College Bulletin_,
May, ’96. The experiment would certainly prove that if X-rays are due to
vibrations, the latter are of a different order from those occurring in
light rays, for the slits exhibited light diffraction very well, but
there was no evidence, by a widening of the image on the plate, that
X-rays had been diffracted in the slightest degree. § 110 and 110_a_.
171. Prof. Haga, of Groningen University, at the suggestion of Mr. J. W.
Giltay, (_Nature_, June 4, ’96,) made some very crucial tests, with
numerous precautions, in reference to the action of X-rays upon
selenium, and the results were so positive that they thought that a
practical application could be made by using selenium for detecting
X-rays, both qualitatively and quantitatively. In repeating the
experiments, it must be borne in mind that one half hour or so is
required for selenium to return to its former degree of ohmic resistance
after being struck by light or heat or X-rays.
_Total number of_ § § _to this place, 199._
------------------------------------------------------------------------