The presentation of the experiments, illustrated with lantern slides, created a sensation among the prominent physicists present. They said that if the experiments described by Professor Ehrenhaft could be corroborated by others they would mark one of the greatest revolutions in modern science, to be ranked with the discovery of the principle of the dynamo by Michael Faraday 113 years ago.

Just as Faraday's discovery marked the ushering in of the age of electricity, it was pointed out, so this discovery of Professor Ehrenhaft, assuming the correctness of his results, would mean the ushering in of a new era in technology based on currents of magnetism. It would mean, one leading physicist said, that we would double the possibilities for building machines-for every electrical machine now in existence we would be able to build a machine utilizing magnetic instead of electric current.

Up to now phosphorescence, which is the afterglow of a substance which has been bathed in strong light, has been considered little more than a pretty phenomenon, limited to relatively few chemicals.

Dr. Lewis found that phosphorescence was a property of all molecules and that it was characteristic of matter in what is known technically as the triplet state. This refers to the energy status of electrons in the molecule. Light can increase the energy of these electrons to the point where the molecule is brought to the triplet state.

In that state molecules give off spectrum lines which constitute a new series of identification marks. They bear no resemblance to the lines obtained with a spectroscope in the ordinary manner.

Ordinary spectrograms of complex substances such as organic molecules are frequently not sharply defined and are not easily interpreted. Often there is a similarity between those given out by entirely different substances.

In the phosphorescent state, Dr. Lewis reports, each substance gives off a highly characteristic spectrum. Chemicals which differ from each other only in the minutest detail under usual analysis will produce noticeably different spectra.

This discovery probably will help to answer some of the long-standing questions about the make-up of the vitamins as well as other chemically complicated substances. It is unlikely, however, Dr. Lewis added, that the phosphorescence of heavy protein molecules will produce spectra within the range of present observing instruments.

This is not altogether a fairy story, but the idea of Sir Charles Darwin, son of the first propounder of the doctrine of evolution, of what might be done if the ultimate properties of matter could be utilized.

It is, of course, nothing to be expected as a practical accomplishment, as most of the materials which would enter into such a ship are now non-existent and some of them probably never can be realized. The great physicist, scientific adviser of the British War Office and a member of a British mission in Washington last year, indulged in the fantasy before a scientific society here the other night.

Such a metal would be l00 times as strong as steel. Hence, only onehundredth of such material would be needed to construct a ship as large as the Queen Elizabeth. But this featherweight ship would require about 30,000 tons of ballast for displacement before a cargo could be loaded. The heaviest substance on earth, the scientist points out, is the metal osmium. The appropriate ballast would be provided by a block of 12 cubic yards.

Sir Charles sees little possibility of cutting down on the size of the engine room, although a possible atomic engine might reduce to practically nothing the amount of fuel to be carried. But eventually the atomic power would have to be converted to steam.

His dream ship would be wired by tin or lead wires cooled with liquid helium, which would make them essentially perfect conductors. Practically no additional power would be needed for all the auxiliary machinery. Copper wire could not be used since copper never becomes a "super conductor."

Up to this point, theoretical possibilities had been discussed, however far-fetched and however far in the future the realization of any of them. But the great physicist then went into a realm of pure fantasy-an arrangement by which a child could send the Queen Elizabeth across the Atlantic with a slight push. This would involve changing all the water in the sea to liquid helium. This substance, which exists only in physical laboratories in minute amounts, has practically no resistance. It would permit dispensing with ballast altogether.

But on a liquid helium sea, the dream ship would almost certainly sink before it completed its voyage because experiments have demonstrated this almost hypothetical substance has the uncanny faculty of creeping upwards over any obstacle.

It would be impossible, for example, to dam a liquid helium river. It would crawl over the sides of the ship, quickly fill the holds and founder the craft.

But, fantastic as the picture seems, Sir Charles explained to the engineers that every bit of it is based on physically demonstrated facts concerning the ultimate properties of matter. All that remains is to realize them.-"The Evening Star," Washington, D. C.

Just as the rings of a tree furnish a means for calculating its age, rings that form in the lens of the eye give an indication of the physiological age of that organ, according to a statement issued by the New York State Optometric Association. At birth the lens is formed of a single piece of homogeneous material. In the course of years a small disklike core forms in the center of the lens. As time passes additional layers form around the core after the manner in which a pearl grows, or like the layers of an onion. With the increase in the number of layers the lens becomes less elastic and it becomes more difficult to focus the eyes.-New York Herald Tribune.

Lightning travels faster going away from the earth than toward it, says Charles F. Wagner, Westinghouse Electric engineer at McKeesport, Pa., according to The United Press.

The most brilliant part of a lightning strike, states Mr. Wagner, moves upward from the earth to the cloud at a speed of 20,000 miles a second-fast enough to make a round-the-world trip before you can draw a deep breath. The downward dive travels at the rate of only 100 miles a second.

"This luminous upward stroke moves along a highway of ionized air established by an earlier stroke from the cloud to the ground," Mr. Wagner said. "Only a few ten-thousandths of a second separate the two, so the human eye sees them as one."

Contrary to popular opinion, it is not the impact of the stroke that pulls a tree from its roots, but rather the heat of the lightning which converts wood moisture into steam and literally "blows up" the tree, according to Mr. Wagner.-New York Herald Tribune.

Calculations recently have been completed on the length of time in which star clusters can exist and retain their identity as such, and their life span has been found to be 3,000,000,000 years. The investigation was made by Dr. Slabrahmanyan Chandrasekhar of the Yerkes Observatory of the University of Chicago, on the basis of a seventy-year photographic history of the cluster of which the Pleiades is the characteristic group.

To the ancients the Pleiades was known as The Seven Sisters, although only six were visible to the eye. To the "eye" of the photographic telescope there are 200 stars in the cluster within a compact volume of ten light-years. Dr. Chandrasekhar's measurements show they have an average velocity of 500 meters a second with respect to the center of the group, while the background stars in this area of our galaxy have velocities of 25,000 to 30,000 meters with respect to this same point.

This compact, densely localized and highly stabilized cluster, Dr. Chandrasekhar recently informed the Philosophical Society of Washington, will break up and its members become dispersed, so that there no longer will be a duster formation. The life span of such a cluster, he calculates, will be 3,000,000,000 years, and since similar conditions exist in other clusters this can be taken as the average life span of star clusters.

Dr. Chandrasekhar calls attention to the investigation made by Dr. V. A. Ambarsumian, the Russian astronomer, into the stability of multiple stars, of which the common double stars are the best known variety, and found that these groups disintegrated by a process in which the distances between the stars increased. The average length of time in which a dose, tight, multiple-star system will break into independently moving stars is 5,000,000,000 years.

These figures are in such dose agreement that the Yerkes astronomer compared them with other cosmic life spans. Scientists are still hesitant about adopting any fixed theories concerning the so-called red shift phenomenon which indicates that stars and galaxies in all parts of the heavens a pear to be rushing away from us at high velocity, the farther away they are the faster they are going.

By tracing the expansion process backward, and allowing for the difference in rates at which they are moving, All of the widely dispersed galaxies, some of them hundreds of millions of light-years distant, would have been concentrated in our local regions of space about 2,000,000,000 years ago about the same length of time that it would have taken the grand cosmos to have exploded into its present dispersed state. It also would account for the dispersion of star clusters and also for the breaking up of multiple-star systems.

Determination of the age of rocks by their radio-active contents, which would also be the age of the earth, gives as the answer 1,500,000,000 to 2,000,000000 years, and Professor Henry Norris Russell, of Princeton, gives the top limit as 3,000,000,000 years.

It is becoming apparent that some interesting events were taking place about two or three billion years ago in our region of the cosmos.