False Hopes in Roentgen Rays

Nikola Tesla Doubtful About Making the Blind See.

WHAT CAUSES "SUNBURN"

Inventor Predicts the Manufacture of Fertilizers from Air by Electricity.

Nikola Tesla's latest experiments have convinced him that the loudly-heralded discovery that X rays will make the blind see has little foundation in facts shown in the laboratories.

"Is it not cruel," said Mr. Tesla, "to raise such hopes when there is so little ground for it? for, first of all, the rays are not demonstrated to be transverse vibrations. If they were we would have to find means for refracting them to make possible the projection of a sufficiently small image upon the retina. As it is, only a shadow of a very small object can be projected.

EXPERIMENTS DOUBTED.

"What possible good can result from the application of these rays to such purposes? I cannot confirm some of the experiments reported. For instance, when a hand is put before the closed eyes it is easy to distinguish the shadow, much the same as before the light of a candle; but when the tube is inclosed and all light from the same excluded I fali to get such an impression. The shadow 13 therefore chiefly due to ordinary light."

Nearly all experimenters with Roentgen rays have noticed that they produce upon the skin the effect of sunburn. Tesla attributes the sunburn effect not to the rays themselves, but to ozone generated when they come in contact with the skin.

"Nitrcus acid," he said, "may also be responsible to a small extent. The ozone, when abundantly produced, attacks the skin and many organic substances most energetically, the action being, no doubt, heightered by the heat and moisture of the skin."

"Owing to this I have always taken the precaution when getting impressions with the rays to to guard the person by a screen made of aluminum wires, which is connected to the ground, preferably through a condenser. The radical means, however, of preventing such actions is to make impossible the access of the air to the skin while exposing by immersion in oil."

In to-day's issue of the Electrical Review Nikola Tesla describes in a way that will be of practical value to physicians and experimenters of all kinds his method of making X ray Impressions.

USE OF ROENTGEN RAYS.

"The Roentgen screen," he says, "is first applied to the body to be investigated, the pressure at the terminals of the tube being very much reduced. The pressure is then slowly and gradually raised. It will be presently observed that, at a certain pressure, the shadow of the object examined is clearest.

"As the vacuum is increasing, the pressure generally rises, and the image gets blurred In spite of the screen getting much brighter, Just as soon as the clearness is slightly alminished, the experimenter should for a few moments reverse the current, lowering the vacuum a little in this manner.

"The current being again given the direction it had at first, the shadow gets again clear, and by such easy manipulation the best result may be secured. An additional advantage, however is gained, because the frequent reversals produce brighter phosphorescence of the screen.

FERTILIZERS FROM AIR.

In currents produced by perfected electrical oscillators, Nikola Tesla sees a greater benefit to the human race than making the blind see. It is possible by these currents to ozonize strongly the atmosphere of a large hall in a few seconds.

The inventor says that for a long time he has been following up the immense possibility of manufacturing fertilizers for the soll from the nitrogen of the air. He says the way now is is opening up for accomplishing this by mechanical means, and that it will prove of immense benefit to agriculture.