provided-about ten pounds, more or less. With my muscles, it was nothing to jump seventy or eighty feet, the difficulty being to keep on the ground at all.

"Now, I suppose you are wondering how it was that the planet was not drawn to the earth by the great attraction of the latter body. It took the scientists less than five minutes to determine the reason accurately. It was because of the composition of Nebula, such ingredients having been put together in its formation as to repel the advances of the earth toward a union, but not enough to drive the lit

that planet from east to west, while it turned over from west to east. The combined motions in opposite directions made our speed about two thousand miles an hour, so that we should circle the earth every twelve hours. This calculation was of the greatest importance, since we would have to time our departure accurately in order to land where we wanted to. If we allowed our balloon to ascend at the wrong time, it was just as likely that we should find ourselves over an ocean as over the land, and just as likely over Africa as over America.

Figures were jotted down, and we then determined upon an exploration of our kingdom.

"At this point I did some figuring myself. It seemed reasonable to me to suppose that, if I could jump seventy feet with little effort, I could run just so many times faster here than I could on the earth. And I proved it. I pointed out to the others a clump of trees about a mile away, and then, asking them to time me, started. My work surprised me beyond expectations, for I leaped into the air about thirty feet at each bound, alighted easily some sixty feet beyond, and took another bound, as simply as if on the earth, yet with an ease that gave me not the slightest weariness. I ran

back and found that I had made the two miles in a fraction under three minutes!

"At that rate,' said I, I can run around this ball at the rate of forty-five miles an hour; and if your calculations are correct, and it is eight miles in diameter, it must be about twenty-five miles in circumference. I can, therefore, if I don't get winded, circle it in less than forty minutes, and I'm going to do it.'

"Two of the party volunteered to accompany me, and off we started at a good clip, the stop watches being out at the word 'Go!' None of us seemed to mind the exertion, if floating lightly in the air can be called exertion; and we ran along through the forests and across the plains with the ease and grace of greyhounds. For half an hour we did not slacken Our pace; but there appeared before us a deep gulley, at the bottom of which was a stream. Here we came to a standstill. The gulch was quite fifty feet deep and nearly a hundred wide at the top; and as far as we could see, there was no better crossing in sight. Elated at our work, and feeling certain we could make the leap, we all ran at it together. Every bound we took was better than the previous one; and when we reached the edge of the arroya, we sprang into the air like birds and landed on the opposite side fully ten feet beyond the edge. After this the going was simple, and we made. the trip safely, having circumambulated the globe in thirty-seven minutes.

"I am not going to tire you with all

the details of the stay on Nebula. Let it suffice to say that we had to wait there twelve hours for the United States to get back to us. In the meantime food was cooked and served. Then, when California was just rounding the edge of the earth from the west, we lifted anchor and started our motor, bidding but a temporary farewell to our little world, for we all fully determined that this should. not be our only trip there. The journey back was the reverse of the conditions in coming away from home; and by operating the powerful machinery, we were enabled to make our landing within a very short distance of the spot we had left but little more than half a day before. But it was moonlight, and the night was beautiful in the mountains. We camped where we landed, and came down to the ranch next morning."

He stopped abruptly and relighted his pipe. I waited for him to continue. "What do you think of it?" he asked. "I think it the most remarkable tale I ever heard," I replied.

"And perhaps you would like a look at our little world?" he asked.

I was instantly alert, and rose quickly from my chair.

"Come along, then," he said, leading the way.

Into the garret we went, where he dug out of a corner a fine hand telescope, which he carried to the dormer window on the east side. Swinging it into a position with its disc pointed at an angle of about 60 degrees, he peered carefully into it, then adjusted it again, screwed it tightly onto a swivel, and bade me take a careful look. I was more than amazed, for before me in the heavens was a globe of dim light, upon which I could, with care, trace the outlines of what seemed to be land and water. For but a moment I looked, and then he took the instrument away from me and turned it from the little planet.

"Now find it," he commanded.

I tried with all my might to locate it, but nothing revealed itself save the stars and the moon.

"That's the reason it has never been discovered," he said; "because astronomers have always been looking for things farther away, ever forgetting the fact

I'

F the average man be asked how the ships of our commercial fleets find their way about the coasts and rivers

and lakes of the United States, he will be apt to tell you that he supposes they use "maps" and navigation instruments. Pressed as to his knowledge of the origin of these "maps," he may inform you that they are made by firms who sell them, or he may say that he guesses the Government makes them. Asked as to how they are made, he will probably "give it up." It is a strange thing, when you come to think of it, that so important a branch of commercially important scientific work as the making of charts of the coasts and the bodies of water of this country, should be so little known and understood. If it were not

for the work of the Coast and Geodetic Survey, our navies, both commercial and war, would be in a very helpless condition in regard to navigation of the coasts and rivers. For while a knowledge of navigation, a few tables, and an instrument or two will take a ship anywhere about the ocean, a chart showing coast lines and depth of water is absolutely essential for navigation near land.

U. S. Coast and Geodetic Survey Now, this chart making is a big subject. The Coast and Geodetic Survey, located in Washington, occupies two large buildings; has a very complete plant for the printing of the charts and the engraving of the plates, and, besides these departments, equips and sends out

many parties each year for making the actual surveys which become charts after a while. This story deals with the work of the plane-table parties, who come after the triangulation parties, and who actually make the plane-table sheets in the field, from nature as a model, from which the topographic details of the charts are obtained.

In the first place, it should be explained that before a plane-table party goes to work, a triangulation party must previously have been over the ground,

or level. The plane table, as used in the survey, consists of a heavy tripod, on top of which is what is called the movement, a device now made of aluminum and brass, to which is attached the table proper. It allows the table to be leveled accurately by means of leveling screws, and revolves in a complete circle, besides providing a tangent screw movement to move the table in a small arc, very slowly.

With the plane table, is used a surveying instrument called an alidade. This

and have determined with great accuracy the exact location of certain points. Some of these points are covered with wooden structures called signals. Sometimes a triangulation point may be a church spire, a tall tree, or other landmark. It makes no difference how long a time elapses between triangulation and planetable surveying, provided the predetermined triangulation points are still visible, or, if destroyed, recoverable. A very large part of this country has been triangulated-all the coast-line and most of the important rivers and lakes.

What is a Plane Table?

A plane table is exactly what its name. implies a table which can be made plane

consists of a small telescope, mounted like a transit, so that its only movement is in a vertical arc. The standard of the telescope ends in a metal base which is long and narrow, the sides of which are absolutely straight and parallel, and accurately in line with the line of vision of the telescope. The telescope is further provided with an eyepiece in which are cross-hairs whose distance apart bears a certain definite, arbitrary relation to the focal length of the objective and the divisions painted on a long piece of wood, called a telemeter rod. These divisions, and the distances between the cross-hairs, are so adjusted that when the rod, held in an upright position, is viewed through the telescope, the number of di