ment had been delayed so long that the patients were already evidently moribund, the ratio is diminished to 8.8 per cent. And if we take into reckoning only those cases in which the serum was applied du ring the first three days, we have 4,120 cases with 303 deaths, a death rate of 7.3 per cent. A still better showing is, of course, made in the cases treated on the first day, amply justifying Dr. Behring's prophecy that the death rate therein would be reduced to not more than 5 per cent. The three days' limit is probably, however, the most reasonable and practical one; and the figures cited warrant the saying that the antitoxin serum, where it has had a fair chance, has reduced the diphtheria death rate to between 7 and 8 per cent. Hitherto diphtheria has been one of the most deadly of all diseases. The proba bility of benefit from the use of antitoxin decreases in appalling ratio after the third day. The death rate in cases treated in the first three days is 7.3 per cent; in those treated after the third day it is 27 per

cent.

A similarly favorable report was made by the London (Eng.) Board of Metropolitan Asylums.

The serum method of treatment has also been developed in Paris, France, by Dr. Roux and his collaborators, for use in cases of cholera; and by the bacteriologists of the Health Board of New York city as a preventive of tetanus.

It is also stated that experiments conducted in the laboratories of the St. Lawrence State Hospital at Ogdensburg, N. Y., go to prove that acute delirious mania is a germ disease, to be treated accordingly.

X Rays. A few additional interesting announcements have been made regarding the wonderful form of energy discovered by Dr. Röntgen, and fully reviewed at the beginning of the present volume (p. 1).

Mr. Edison has advanced the hypothesis that the X rays are really sound vibrations, of course not those with which we are all familiar, but of very much smaller wave length and vastly greater rapidity. He bases this hypothesis on a study of certain shadows appearing in various radiotypes, which appeared inexplicable except on the theory that they were sound shadows, the peculiarities of which are well known. He gives the following account of his experiments and conclusions:

"The fluorescent bulb was placed on one side of a steel plate, the observer being on the opposite side. When the fluoroscope was placed against the steel plate directly opposite the bulb on the other side, no light was ob served; but when the fluoroscope was made to approach within six inches of the edge and well within the shadows, it lighted up. The direction of the X ray was found by a moving bar of iron, so as to obtain the sharpest image.

The second fact which possibly tends to confirm the sound-wave theory is that liquids do not fluoresce with the ray, at least none that I have tried. Crystals alone fluoresce, except in one or two cases, such as precipitates, and these may not be amorphous. The crystal is resonant to the wave.

The third observation is that a tube with a vacuum so low as to give striæ, and from which ordinarily no X ray can be obtained no matter how long a dry plate is exposed to it, can be made to give the ray by a powerful blast of air on the spark of the break wheel of the primary and a spark gap in the secondary, the wires of which are guarded up to the very end.

"Another observation is that the sharpness of the shadow depends on the abruptness of the break. A very weak bulb may be made to give sharper shad

ows than one giving twice the luminosity in the fluoroscope, which has a connec tion with this theory. Another fact is that when tubes are on the pump con. tinuously, the vacuum will depend upon the pump, that is, the amount of mercury running per minute. The vacuum will reach a certain stage and keep that way for several days, the pump being able to reach a certain exhaustion, and no further, the air brought in by the mercury being the limiting point."

Mr. Tesla, too, has continued his studies of the new radiance. He had early demonstrated the possibility of reflecting X rays, and has found that the metals, when ranged according to their powers of reflecting X rays, correspond to the contact series of metals in air. His theory, it will be remembered, is that the rays consist of material particles emitted from the vacuum bulb. He makes the following observations:.

"Further investigations concerning the behavior of the various metals in regard to reflection of these radiations, show that Volta's electric contact series in air is identical with that which is obtained when arranging the metals according to their powers of reflection, the most electro-positive metal being the best reflector. This series is magnesium, zinc, lead, tin, iron, copper, silver, gold, and platinum. The last named metal should be found to be the poorest, and sodium one of the best, reflectors. This relation is rendered still more interesting and suggestive when we consider that this series is approximately the same which is obtained when arranging the metals according to their energies of combination with oxygen, as calculated from their chemical equivalents. **Should the above relation be confirmed by other physicists, we shall be justified to draw the following conclusions: First, the highly exhausted bulb emits material streams which, impinging on a metallic surface, are reflected; second, these streams are formed of matter in some primary or elementary condition; third, these material streams are probably the same agent which is the cause of the electro-motive tension between metals in close proximity or actual contact, and they may possibly, to some extent, determine the energy of combination of the metals with oxygen; fourth, every metal or conductor is more or less a source of such streams; fifth, these streams or radiations must be produced by some radiations which exist in the medium; and sixth, streams resembling the cathodic must be emitted by the sun and probably also by other sources of radiant energy, such as an arc light or Bunsen burner."

Professor Elihu Thomson announces that "Röntgen rays are produced by the bombardment of any surface within the Crookes tube by cathode rays, or the radiant matter of Crookes," and that they are emitted in all directions from the bombarded surface, and are not special to any particular direction. They are even emitted backward toward the cathode from which the rays which bombard the surface are sent."

A professor in King's College, London, Eng, announces that the X rays, when focused to a point, do not cross and diverge again beyond the focal point, as light rays do, but continue on as a solid pencil of rays.

Genuine diamonds can be distinguished instantly from imitations, by means of the X rays. Being composed of carbon, diamonds are almost perfectly transparent to X rays; whereas glass or other mineral stones are opaque. The difference is instantly noticeable in the fluoroscope, the shadow of a spurious gem being much darker than that of a diamond.

Magnetographs.-Professor John S. McKay of the Packer Institute, Brooklyn, N. Y., has obtained interesting pictures, which he calls "magnetographs," resembling X-ray prints in being silhouettes of objects excluded from light, but differing from them in being produced by the action of magnets.

He placed a paramagnetic ubstance upon the sensitive film of an ordinary photographic plate, an 1 brought a magnet or electro-magnet

near to the other side of the plate. A clearly defined image of the object on the plate was the result, and this became a shadow in the positive taken from the negative plate. Silhouettes of a key, a screw, a wire gauge, and other objects were obtained. By placing the plate, with its sensitive side facing the poles of the magnet, and placing a disc of iron nearly as large as the plate on the opposite side, "shadowgraphs" were obtained of non-magnetic bodies placed on the other side, between the plate and the poles of the mag

Det.

"These experiments seem to indicate," says Dr. McKay, that the ether in the field of a magnet is in a state of permanent stress, and that any change in magnetic force caused by motion of the armature or variation of current strength produces a change in the degree of stress, and thus originates ether waves capable of affecting the ordinary photographic plate.

"Perhaps the shadow pictures produced by long exposure to sunlight, which some think to be a Röntgen effect, may be caused by magnetic waves from the sun; and may not the Röntgen rays themselves be something analogous to these magnetic rays? '

An Absolute Chemical Vacuum.-Professor Elmer Gates, director of the new Laboratory of Experimental Psychology at Washington, claims to have recently produced the first absolute chemical vacuum known to science.

The method, in a word, is to fill a tube made of glass melting at a very high temperature with other glass melting at a much lower tem perature, and to draw out the latter by means of suction, leaving only enough to seal the mouth of the tube. Of course the absolute character of the vacuum thus produced remains to be demonstrated.

Miscellaneous.-Lord Rayleigh has made a new determination of the specific gravity of argon, finding it to be 19.940 referred to O2 as 16. The refractivity of argon is 0.961, while that of helium is 0.146, compared with air as unity. The result in the case of argon is very unfavorable to the view that this gas is an allotropic form of nitrogen. The refractivity of helium is remarkably low, the lowest previously known being that of hydrogen, which is nearly 0.5 that of air. The results of determinations of viscosity were for helium 0.96 and for argon 1.21, referred to dry air. The latter number is somewhat higher than that for oxygen, which has stood at the head of the list of the principal gases in this respect.

A flying machine, called an aerodrome, invented by Professor S. P. Langley, secretary of the Smithsonian Institution, is described by Professor Alexander Graham Bell as having demonstrated the practicability of mechanical flight.

Details of the invention are not given. The machine, as at present constructed, is built of steel, and driven by a steam engine, but carries only enough water for a very brief flight.

A most important discovery is credited to Professor C. S. Hastings of the Sheffield Scientific School of Yale University, namely, of a method by which the hitherto insu

perable difficulties resulting from secondary chromatic aberration in the use of telescopes can be eliminated without the use of other than the ordinary silicate glasses.

After much labor he first demonstrated theoretically a new method by which the secondary chromatic aberration, which had resisted solution for almost a century and a-half, might be remedied. He next constructed a telescope with a ratio of focal length to diameter of only eight and a-half, for use with the spectroscope. This has fulfilled in every way the hopes founded upon the theoretical investigation. It shows the solar spectrum with absolutely unvarying focus from extreme red to extreme violet, eliminating all secondary color aberration. While the experiment has not gone beyond this, there is little reason to doubt that the method is applicable to telescopes of all sizes. The discovery, it is said, will add at least 10 per cent to the power of telescopes.

66

The Kleidograph" is the name of a simple mechanism resembling an ordinary typewriter, devised by Superintendent W. B. Wait of the New York city Institution for the Blind, whereby one can prepare point text for the use of the blind much more rapidly than with the customary stylus and tablet.

A horseless carriage race, under the auspices of the Cosmopolitan Magazine, for $3,000, was run on May 30, from City Hall, New York, to Irvington-on-the-Hudson and return, a total distance of about fifty-two miles.

There were nearly thirty entries, but only six carriages appeared to compete-four made by the Duryea Motor Company of Springfield. Mass., one Booth-Crouch carriage, and one Roger carriage, a French invention. The winner was Charles E. Duryea of Springfield, Mass. The start was made at 11:55 A. M., the first carriage arriving back at 7:13 P. M. The award was made on the following points, the maximum being 100: speed, 35; simplicity of construction and durability, 30; ease in operating and safety, 25; cost, 10.

ART.

AN unpleasant controversy arose in the latter part of May between the National Sculpture Society and the committee of the Society of the Army of the Tennessee appointed to select a design from among several submitted for an equestrian statue of the late General William T. Sherman. The statue is to be erected in the esplanade in rear of the Treasury building in Washington.

It appears that the committee asked and obtained advice from the National Sculpture Society in inviting sculptors to submit models in

competition; and that they then invited to a second competition other sculptors than the ones recommended, and finally accepted the design of a sculptor who had not been designated by the committee of experts of the Sculpture Society.

The committee of experts consisted of J. Q. A. Ward, A. St. Gaudens, O. L. Warner, and D. C. French, sculptors, and Bruce Price, architect. Four models were submitted-by Paul W. Bartlett of Boston, C. H. Niehaus and J. Massey Rhind of New York city, and Carl Rohl Smith of Germany, now of Chicago, Ill. The committee of experts found the models of Bartlett and Niehaus to be the most artistic, and recommended a further competition between these men. In spite of their advice, the design of Mr. Smith was finally accepted by the statue committee. Mr. Smith is himself a member of the National Sculpture Society, and had acquired a high reputation in both Europe and America. Of the six members of the statue committee, four, on the only ballot taken, voted in favor of Mr. Smith's design. Letters of protest against final ratification of the award were addressed to General G. M. Dodge, president of the Society of the Army of the Tennessee, and to Secretary of War Lamont, by Mr. J. Q. A. Ward in behalf of the National Sculpture Society-to which the statue committee made a strong reply.

The E. L. Rodgers collection of old and modern engravings and etchings-probably the most representative gathering of the works of noted engravers ever offered for sale by auction in America-was sold in Baltimore, Md., in April, realizing about $14,000.

EDUCATION.

THE policy of the United States government regarding the use of public funds for the support of sectarian educational institutions, is outlined in our review of proceedings in congress (p. 357). After June 30, 1897, no money is to be appropriated by congress for such purpose.

The important questions of restoration of separate schools in Manitoba, school reform in New York state, and the pending Education bill for England, are also treated elsewhere in this number (Manitoba, p. 401; New York state, p. 395; England, p. 418).

Through the efforts of Dr. H. J. Furber, Jr., of Chicago, Ill., assisted by an American committee consisting of the presidents of Columbia, Yale, Harvard, Cornell, Johns Hopkins, Michigan, and Clark universities, together with Dr. W. T. Harris, commissioner of educa tion, and Professor Simon Newcomb, the doors of colleges and universities in France have at last been thrown open