The Boy with the U. S. Weather Men Part 36

"And the beach," the young observer continued, "that once white beach with its stretches of sand, what did that look like, beyond the engineers' parade ground, where the wrecked schooner lay? Mis-shapen, distorted, blotched, drabbled and crimsoned, it spread away to the horizons, east and west, its scars showing under the rays of the sun which shone out from the mares' tails of the departing hurricane. Part of it had disappeared under the waters, now rapidly subsiding. The great causeway was a ma.s.s of ruins, but the sea-wall, the two-million dollar sea-wall, stood with its front to the ocean, grimly defiant still, the conqueror against the rage of the tempest, and an unwrecked Galveston shone triumphant.

"But I should do the hurricane a grave injustice," he continued, "to leave you boys with the story of Galveston alone. Its terrors were far more widespread than that. On my way here from Galveston, I saw the ravages of the storm inland. Everywhere on the flat prairie near Texas City were ruined houses and outbuildings, many of them absolutely abandoned, others still with a corner occupied by their ruined owners.

Trees were broken short off or up-rooted and lying prostrate. The hurricane which had been foiled of the slaughter which had been granted to its predecessor fifteen years before, had swept on, mile after mile, for hundreds of miles, slaying and wrecking as it went. Acres of pear orchards were stripped as though the giant of the winds had drawn each separate branch through his clenched fists. For twenty miles inland the prairie gra.s.s lay prostrate. Twelve miles from the sh.o.r.e I saw a fis.h.i.+ng schooner there, her masts still standing, and near it lay a child's rocking-horse, a cradle, a boy's baseball-bat and a five hundred pound bale of cotton.

"Not fifty yards from the hastily relaid railway track, I saw a strange example of the fury of the waves and wind. On the floor of the first story of a negro shack, without a sc.r.a.p of furniture around it, with no wreckage or piece of wood to be seen in any direction, a rude cabin indeed, was a large grand piano, its boards warped by the water and the sun, but otherwise uninjured. From what house in Galveston had this floated, to find a resting-place on the floor of an un-roofed and un-walled negro's cabin? Around it was not a sign of wreckage save the bodies of scores of drowned horses and cattle and, among them, many human forms.

"No census will ever tell how many were killed in that stretch of prairie between Galveston and Texas City. Years hence men will stumble over human bones on that gra.s.sy plain and give burial to some victim of the greatest storm that ever visited American sh.o.r.es. Yet, withal, that the hurricane of 1915 claimed six hundred victims instead of tens of thousands was due alone to the warnings of the Weather Bureau, to the heroism of the men and women of Galveston and to the craft, skill and honesty of the men who built the great sea-wall."

CHAPTER X

STRUCK BY LIGHTNING

There was but little further interest in kite-flying that afternoon, when the young observer ended his story of the Galveston hurricane. The boys had been brought close to danger and they crowded around the stranger with questions concerning the hurricane. The lads were all the more thrilled by reason of the fact that the sky was becoming dark and ominous, and that, even while the stranger spoke, the clouds grew more threatening.

"There might be a hurricane coming now," said the youngest of the group, looking fearfully at the sky.

"No," answered the observer, "that's nothing but a thunderstorm. You'll never forget the look of the hurricane as it comes near, if you've seen it once."

"Nor a tornado," put in Ross, and he told of Dan'l's death and of his narrow escape with Anton.

"I was in the St. Louis tornado," the observer rejoined, and in turn he told of the devastation that had struck the city in 1896.[1]

[Footnote 1: While this book was in press a most destructive series of tornadoes visited the United States, Illinois especially suffering.

Hundreds of deaths were recorded.]

Meantime the thunderstorm was drawing closer and the thunder and the lightning grew gradually nearer.

"Do you suppose, sir," asked Tom, "that it would be safe to send up the kite? I've been listening to the hurricane story, and haven't taken the weekly observation yet. Franklin sent up a kite in a storm."

"It might be safe, but I wouldn't advise it," answered the Forecaster.

"Franklin did it deliberately, for a different purpose, and it was because of his experiment with a kite that we first found out about lightning."

"Yes," answered Tom, who knew the story well, "and he collected sparks from the string. But that was a silk string, Mr. Levin. I should think this piano wire would be much worse."

"Why?" asked the Forecaster. "On the contrary, it would act as a lightning-rod. Your kite reel is of metal and fastened to the ground.

Wire is a much better conductor of electricity than the body, so that there's less likelihood of your being struck."

"Is it the difference between a good conductor and a bad one that makes people put up lightning-rods?" asked Fred.

"Certainly. All that a lightning-rod does is to convey to the ground the electricity that is about to strike a building. That's the whole system of lightning protection. I can explain it to you fairly well by trees.

You know in fairy tales that some trees are supposed to be wicked and other trees are supposed to be good?"

"Yes, sir," put in Anton, "Dan'l used to talk about that. He always used to say that the oak tree was a black witch tree and that the beech tree and the alder tree were white witches."

"Like nearly all folk-lore," replied the Forecaster, "there's a mighty good reason for that superst.i.tion. Folk-lore, after all, is merely keen observation reduced to a saying or a story. It is true that the oak-tree is a black witch so far as lightning is concerned and that the beech and alder are white witches. The proportion of trees struck by lightning has often been counted and for every fifty-four oaks struck, only one beech, or birch, or maple or alder is struck. Elms are fairly dangerous, being forty to the beech's one, and pines are less so, their ratio being fifteen. Not only this, boys, but a good deal depends on the way in which a tree is struck. An oak-tree may be riven into splinters, showing the terrible resistance that it gives to the stroke. A beech-tree, usually, is killed outright, yet shows but little outward injury. The oak has resisted the current, it is a bad conductor; the beech has allowed the current to flow directly to the ground.

"So, boys, if you are in a mixed forest and stand beneath a tree, the figures show that you are fifty-four times as likely to be struck with lightning when standing beneath an oak, instead of a beech. Not only that, but if the oak be struck, the lightning may jump from the tree to you more surely than it would from a beech-tree.

"It's surprising," he went on, "but even trees of closely related character show very different effects of lightning. 'Nothing but lightning,' writes John Muir, 'hurts the Sequoia or Big Tree. It lives on through indefinite thousands of years, until burned, blown down or undermined, or shattered by some tremendous lightning stroke. No ordinary bolt ever hurts the Sequoia. I have seen silver firs split into long peeled rails radiating like spokes of a wheel from a hole in the ground where the tree stood. But the Sequoia, instead of being split and s.h.i.+vered, usually has forty to fifty feet of its brash knotty top smashed off in short chunks, about the size of cord-wood, the rosy-red ruins covering the ground in a circle one hundred feet wide or more.

"'I never saw any that had been cut down to the ground, or even to below the branches, except one about twelve feet in diameter, the greater part of which was smashed to fragments. All the very old Sequoias have lost their heads by lightning. All things come to him who waits, but of all living things, Sequoia is perhaps the only one able to wait long enough to make sure of being struck by lightning. Thousands of years it stands ready and waiting, offering its head to every pa.s.sing cloud, as if inviting its fate, praying for Heaven's fire as a blessing, and when, at last, the old head is off, another of the same shape immediately grows on.'"

"And then, I suppose," said Fred, "it will never be struck again.

Lightning never strikes twice in the same place."

"Oh, yes, it does," said the Forecaster. "That's all nonsense. Take the Eiffel Tower in Paris, for example. That's struck nearly every time there's a thunderstorm. But lightning can't hurt the Eiffel Tower because practically the entire building is a lightning-rod and it has been very carefully grounded into deep wells, a long way below the ground."

"I've been wondering," said Anton thoughtfully, with his characteristic opening, "just how a thunder-and-lightning storm happens. You promised to explain it to me, Mr. Levin," he continued, "and you never have."

"Very good," said the Forecaster, briskly, "I'll explain it now. And you couldn't have picked a better day for your question, Anton, because we can see the tail end of that thunderstorm going off to the east, and, if I'm not mistaken, there's another one coming up to the south-west. Do you see that layer of cirro-stratus clouds?"

"Yes, sir."

"And do you notice those festoons of cloud, slowly coming down and dissolving--you see there's one small one there, and another one a little larger, behind?"

"Sure!"

"Well, those are the heralds of a thunderstorm. We've only seen those since my nephew began talking about the hurricane, about an hour ago.

Away off on the horizon, though, you can see a bigger bunch of those festoons, dropping from the five-mile height of the cirro-stratus and condensing away down lower. This heat that we're now feeling will diminish, just as soon as that cloud covers the sun, not because the sun is hidden, but because of a change of wind."

"But the storm's coming up at right angles to the wind," said Tom, "the wind's a little east of south."

"It'll blow from the north-east presently," declared the Forecaster oracularly.

"Directly opposite to the storm?" e.j.a.c.u.l.a.t.ed the kite expert in surprise.

"Certainly," was the answer, "that's a part of the thunderstorm formation. You can see now," he continued, "how the thunder heads of c.u.mulo-nimbus are beginning to show, leaden in color below, with the white billowy tops. They're very thick, those ma.s.ses of cloud, perhaps two miles thick, and the gray rain curtain trails along behind them.

Well, Tom, what is it?" he added, turning to the boy, who was claiming his attention.

"The wind's s.h.i.+fting," answered the lad.

"To the eastward? Of course. It'll be north-east in a minute or two, as I told you. It's got to be."

"But why, sir?" asked Tom. "I don't see why a surface wind should have to blow up against a storm."

"That," said the Forecaster, "is quite easy. If the rain is falling, it brings down a ma.s.s of cold air with it, displacing the warm air that lies before the advancing storm. The warm air is driven forward, but, at the same time, the descending cold air requires warm air to replace it in its turn, and the warm air, therefore, curves backward and flows into the upper portion of the storm cloud, where its moisture is condensed as rain. So, my boy, a little distance in advance of a thunderstorm there are three currents of air, an upper current of cold air, traveling in the same direction as the storm, and driving the cirrus clouds before it; a current of warm air, going in the opposite direction to the storm and pouring a torrent of warm air into the cloud; and the cold squall, which drives out from under the thunder-cloud and which comes in violent gusts."

"But I thought," said Fred, "that thunder and lightning came from two clouds banging together. If most of the thunder storms travel from the west, where does this banging come in?"

"It doesn't come in at all," the Forecaster replied; "thunder and lightning do not result from clouds striking each other. It's not quite so simple as that.

"The lower air is full of positive electricity just as the surface of the earth is charged with negative electricity. As you know, boys, rain is formed by a lot of little drops of moisture combining to form one large drop, which, when it is heavy enough, falls to the ground. Now the surface of every drop of moisture is charged with electricity. When these drops come together to make one big drop, the surface of the big drop is proportionately much smaller than the combined surfaces of all the small drops. There isn't room enough on the surface of the big drop to hold all the electricity that existed on the surface of the larger number of smaller drops and, therefore, a great deal of electricity is set free.

"Only a few flashes of lightning reach the earth. Most lightning-flashes occur between two cloud ma.s.ses in the body of the thunder-cloud.

Photographs of these show them to consist of scores of fine branches which jump from one cloud to the other, the flash being strong or weak according to the distance to be jumped. You can see that a very faint flash could jump a distance of an inch, but that it would take a stronger current to jump a yard, and that a terrific force of electricity must have acc.u.mulated before the current is strong enough to break down the resistance of the non-conducting air and jump a quarter of a mile. When lightning is attracted by the earth, it means that the air between the thunder-cloud and the earth is being subjected to a constant strain, and the weakest place gives way first. The weakest place, generally, is the place when the jump is shortest and there is a good conductor available.