times produced wonderful cures. Of course, in such cases, it is necessary for the force of the electricity to be intelligently regulated by the doctor. It appears, however, that sick people who have accidentally received powerful lightning strokes have sometimes been wonderfully improved in health thereby. There is no doubt whatever that these unexpected and unusual cases of electrical treatment have resulted in restoring sight to the blind, hearing to the deaf, and speech to the dumb. So, too, people who have suffered for many years from paralysis, have suddenly recovered the ability of moving their limbs after a stroke of lightning. Despite these facts, however, and their authenticity appears to be unquestioned, I very much doubt whether many could be found to take the risk of electrical doses applied with so lavish a hand.

Before closing this chapter reference should be made to the so called lightning photographs that are frequently found on the bodies of those killed by lightning flashes. The commonest of these markings are various tree-like forms. Now, since dangerous lightning flashes are most common in summer when the people killed are apt to be under trees, it is natural, perhaps, to believe that these markings are photographs of the trees. It is far more likely, however, that they are only the engorged blood vessels, or capillaries near the surface of the skin, that have been filled with blood by physiological causes connected with the shock.

But there are cases in which markings other than those of trees have been found on the skin. Flammarion tells the story of a monogram consisting of two Roman letters being impressed on the thigh of a man struck by a lightning flash. On being taken to the hospital the resident physician was greatly surprised on recognizing this monogram as the same as one marked on a steel plate of a tortoise shell purse he had recently lost. Inferring from the position of the mark on the man's thigh that it was the photograph of a purse, probably in the man's pocket, he had

his clothes examined, and was surprised to find that his supposition was correct. His patient was evidently either a thief, or had found the purse and placed it in his pocket.

Another case is given in which some remarkable things were done by a lightning flash that, on the 18th day of July, 1689, struck the Church of the Saviour, at Languy. The most notable was that it left on a part of the communion cloth markings of some of the words on a card, on which the canon of the mass had been printed.

In both of these cases it is claimed that the photographs were produced by lightning; in the case of the purse, a photo

graph of the steel monogram;

in the case of the church, a photograph of the gilt letters printed on the card resting on the altar cloth. But I think there can be but little doubt that these pictures were produced in an entirely different way. They were simply stains caused by the volatilization or deflagration by electricity of the iron letters of the monogram, or the gilt letters of the card. Such pictures can easily be reproduced at any time as follows. Suppose, as in Fig. 57, a piece of paper is cut by suitable outlining and perforation to represent a portrait of Franklin, and that this paper is placed on a piece of white silk. A sheet of gold leaf is placed on the paper and strips of tin foil A, A', are placed at the top and bottom as shown; two other pieces of tin foil are placed at right angles to these as at B, B'. If, now, a Leyden-jar discharge be passed between the strips, the gold leaf is volatilized by the intense heat, and the gold vapor leaves a purplish black stain of gold on the silk in the form of the

DISCHARGE

design traced on the paper. A similar action probably occurred in the two cases just cited, whereby the monogram was impressed on the man's skin from the vaporization of the iron, and the gilt letters on the printed card were similarly impressed on the silk of the altar cloth.

CHAPTER XXIX

ST. ELMO'S FIRE

According to ancient mythology, Castor and Pollux, the sons of Jupiter and a daughter of man, were highly esteemed by the sailors, who regarded them as their patrons. Castor was celebrated as a horse tamer, and if the stories told of Pollux are true, John L. Sullivan, James Corbett, or Tommy O'Brien might with reason have hesitated to meet him in the ring had they lived in his time; for, Pollux was a great boxer. These demi-gods took part in the renowned expedition of the Argonauts. While on the ship Argo, a storm arose; and the favor of the gods being invoked, two stars immediately appeared on the heads of Castor and Pollux and the danger immediately ceased. For this reason, Castor and Pollux were worshipped by the ancients as the special protectors of seamen.

When the atmosphere is highly charged with electricity, faintly luminous tongues of fire sometimes appear at the ends of bodies in connection with the earth, such as the masts of ships, the points of lances, the branches of trees, etc. When two tongues of fire appear on the masts or yards of ships, they are regarded by sailors as foretelling a prosperous voyage; for then it is believed that the spirits of Castor and Pollux have come aboard the vessel and will conduct them in safety to their haven. If, however, only one tongue of flame appears disaster is indicated, and shipwreck threatened.

The appearance of these faintly luminous tongues of flame on the ends of the javelins and lances was, in a similar manner, regarded by the ancients as a fortunate omen. Such omens were frequently seen during the ancient wars.

According to Dionysius of Halicarnassus, just before the Romans were about to fight against the Sabines, and were greatly discouraged by reason of their inferior numbers, flames appeared on the long iron points of the lances they had struck in the ground; so, taking heart, they went fearlessly into the fight and succeeded in overcoming their enemies.

As you know, sailors are very superstitious. The legend of Castor and Pollux has been forgotten in most parts of the world, but the appearance of the faintly luminous tongues of flame is still hailed almost everywhere as an evidence of the presence of the spirits of saints who have come to protect the ship. Among a variety of names given to these appearances that of St. Elmo's fire is most commonly employed to-day.

But the phenomenon of St. Elmo's fire can be readily explained without recourse to the supernatural. It is a phenomenon due to the presence of free electricity in the air.

The electricity of the atmosphere does not always pass through the air from charged clouds to neighboring clouds, or to the earth, as in the case of lightning. This discharge frequently takes the shape of the faint tongue of flame now known as St. Elmo's fire.

When an insulated conductor containing a large quantity of electricity is discharged by the approach of a blunt earthconnected body, an almost complete discharge occurs by means of a rush of electricity that jumps across the intervening air space, accompanied by a sharp crack or explosion. This is the so-called disruptive discharge, that, as we have seen, constitutes the lightning flash when the charged conductor is a cloud.

If, however, the distance between the two bodies be increased, instead of the discharge taking the form of a single bright flash, it takes the form of a brush of faint light, of a pale blue color, and of so feeble an intensity that it is in