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DISCOVERY AND INVENTION

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be an every-day thing to go from place to that—will fly much faster than 50 miles place through the air. Perhaps some of

an hour. you may find a field of occupation in Then at an elevation of two miles high bringing this about.

in the air there is a constant wind blow

ing in the general direction of Europe FLYING ACROSS THE ATLANTIC

having a velocity anywhere from 25 to Even today we have startling proposi- 50 miles an hour. tions to do things that are apparently im As the net result of ali these things, possible. A man proposes to try this there can be little doubt that any ordisummer to fly across the Atlantic Ocean nary machine that is able to support itin a heavier-than-air flying machine. The self in the air at an elevation of two miles strange thing about the matter is that ex high will attain a speed of at least 100 perts who have examined into the possi- miles an hour in the direction of Europe, bilities find that he really has a fighting and that means going from America to chance.

Europe in a single day. You see the distance is less than 2,000

Calculation shows that, taking all these miles from Newfoundland to Ireland.

circumstances into consideration.

best machines should be able to cross the This means that if you could go at 100

Atlantic in 13 hours. I hardly dare to miles an hour you would cross the At

say it aloud for publication. It is suffilantic in 20 hours—less than a day. Just ciently startling to know that i: is not think of that. Well, we have flying ma only possible, but probable, that the paschines that go at a greater speed than sage may be made in a single day. But that. We already have machines that if, as I imagine, it can be done in 13 could cross the ocean if their engines can hours, you may take an early breakfast keep going for 20 hours.

in Newfoundland and a late dinner in Of course, these are exceptional ma

Ireland the same night. chines; but even the ordinary machines Now, I will not take up any more of of today make 50 miles an hour withi your time. My idea lias been to point ease. Now, a flying machine flies faster out to you how great discoveries and inas you go higher up, because the rarer air ventions have originated from very little offers less resistance to the motion, while things, and to impress upon your minds the propeller gives the same push with the importance of observing closely every the same power, whatever the elevation.

little thing you come across and of reaAs you get into rarer air the propeller soning upon it. simply spins round faster.

Indeed, as Smiles very happily puts it, 50-mile-an-hour machine flying two "The close observation of little things is miles high in the air—and we have ma the secret of success in business, in art, chines that have gone twice as high as in science, and in every pursuit in life."

OUR GUARDIANS ON THE DEEP

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By William JOSEPH SHOWALTER N A very general way the people of the sea in ships, the Coast and Geodetic the United States know that there is Survey stands between them and the

a government bureau in Washington perils of the deep, by furnishing the sailcalled "The United States Coast and Geo ing directions that preserve those ships detic Survey." Yet little indeed do they from harm. Do they live on lots that appreciate its many activities-activities have been surveyed and on streets that which touch them, even though they are have been laid out by a civil engineer, unconscious of the contact, almost every the Survey has contributed to the accuhour of every day of their lives.

racy of the work. Do they drink water Do they or their friends go down to from city water mains, the fundamental

THE SWEEP WITII WIIICII TI COAST SURVEY FINDS SUNKEN ROCKS This is the most reliable apparatus yet (levised for discovering the dangers to navigation that lurk beneath the surface of the sea. It is known as the wire sweep, and consists of a wire of any desired length, supported at intervals by buoys so arranged that the wire can be lowered to any given depth. The sweep, is then attached to two or three small power-boats, depending on its length, and is towed slowly along. The wire catches lipon any obstacle thai il encounters. This obstacle is then further investigated by means of lead soundings. These wire sweeps vary in size from 100 feet to over a mile in length, and have been used to it depth of 45 feet (see page 660).

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RUNNING A LINE OF SOUNDINGS (SEE PAGE 659) This picture shows a sounding party in Baltimore harbor. The two observers are seen determining the position of the boat by sighting with their sextants upon beacons on the shore. In the bow the leadsman stands ready to cast the lead, while amidships is the recorder, all ready to note down the observations.

leveling work of the Survey enters into the consideration. In a hundred ways the work of the Coast and Geodetic Survey comes home to every one, and behind the curtain of its somewhat puzzling name it is engaging in a wide range of wonderfully interesting as well as useful activities.

WE ILAVE 40,000 MILES OF SHIORE-LINT TO

BE CILIRTED In these days of great steamships and vast commerce it is necessary that minute information concerning our coastal waters be in the hands of navigators. I single sunken rock in the path of water traffic may send hundreds of souls to the bottom of the sea: a single point of shifting sands carried hither or thither by river or

ocean current may ground a steamer; a single unplotted wreck on the bottom of a harbor may do millions of dollars' worth of damage.

For 96 years the work of charting our

coasts and making safe the water roads along our shores and within our harbors has been going on. Rather a long task it has been ; but then we have rather a long coast-line to survey. According to trend, it is 16,000 miles long; but when it is measured so as to include the shore-line of all large islands. bays, sounds, and estuaries within tidal range, it becomes upward of 10,000 miles long.

Furthermore, that coast-line is never the same. Its main features may be as fixed as the eternal hills, but many of its smaller features are as unstable as the shifting sands of the desert; and these affect every ship that sails its waters. Between 1835 and 1908 Rockaway Beachi, near New York, grew to the westward at the rate of nearly 8 inches a day. In 73 years Coney Island's western end has shoved itself farther westward about 1,000 feet.

When Vancouver explored Columbia River he found a single straight channel there. By 1831 Sand Island had

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TIE SITIOSIL GEOGR\PHIC MAGAZINE

creases.

appeared, creating a second channel. aces to navigation until they are located Since that time it has moreno miles in and marked on the sailing charts. For a northwesterly direction, and finally has instance, the new super-dreadnought leau closed up the northern channel.

Bork today would run aground in a thou

sand places along the Atlantic coast where OWING TO ITIDS, TIDES, IND RIVERS, TILE

the Oregon could navigate with impunity WORK IS SEVER COMPLETED

in the day when it was the crack ship of It is obvious therefore that the work the Imerican navy; thus the Coast and of surveying our coast-line can never be Geodetic Survey must always go deeper finished, because the winds, the tides, an! with its investigation of the bottom of the rivers continually alter its minor de navigable waters as the draft of ships intails, thereby making new investigations necessary. These changes must be kept track of and charied and the mariners

I MIRIVER'S PICTURE-BOOK warned against them, else, contiding In short, the object of the coast survey the accuracy of the charts, they would is to make a series of map pictures by literally be led into unsuspected traps.

which navigators may read every detail The location of all lighthouses, buors, of coastal or harbor conditions that will aruticial and natural objects on the shore enable them to steer clear of all dangers. must be charted, and every other aid to These pictures must carry to the eye of navigation that will tell the skipper of the mariner every feature of the shoreany ship exactly where he is at" and line, every important feature of the botkeep that information at hand all the ton over which his ship has occasion to time. l'iers and deepenedl channels pass, as well as that over which dangers change the conformation of a harbor, and forbid it to pass, and every detail of cursand-bars rise up or disappear with con rent, tide, and compass behavior that ensiderable frequency. Without a proper ables the mariner to keep in safe waters notation of these things, navigation would and out of dangerous channels. be unsafe and insurance rates would be On the map are located all the physibigli.

cal features of the neighborhood - its Sor is this all. Varine architecture is high-water line, its low-water line, its offprogressing, and with that progress ships lving rocks, its streams, the elevations of are growing longer, their waist-lines are its hills, its towns, roads, lighthouses, getting broader, and their drafts are be aids to navigation, church spires, tall coming deeper. In 1818 the loaded draft chimneys, peculiar rocks and trees, and of the 20 largest ships in the world ar the like. eraged 19 feet. In 1873 the average of

MAKING THE SOUNDINGS the 20 largest ships was 24 feet, while eren in 1898 the average of the 20 largest In ascertaining the depth of the water was only 20 feet. The length of the 20 and locating all the under water obstruelargest ships in the world rose from an tions to navigation, a careful record of average of 390 feet in 1873 to 640 feet the fluctuations of the tide while the

It is obvious that a survey thor soundings are being made must be kept. ough enough to meet conditions in 1873 It would not suffice to measure the depth youll be wholly insufficient to meet con of the water if its height above mean low ditions in 1014.

sea-level were unknown for the moment Once it rock that was 25 feet below of measurement. To determine this a mean low water vas of no interest to registering tide gauge is usel-a sort of navigators; today three-fourths of our float attached to a mechanism in which navy and half of our shipping would be a pen traces the rise and the fall of the in danger with such rocks inchartea water on a roll of paper which a clock There are thousands of rocks dotting the causes to revolve under the pen. under-water sections of our harbors and Two methods of sounding are used, the shore-lines that could be neglected 20 one employing the lead line and the other !ears ago, but which today are great men

the wire sweep

In lead-line soundings

in 1903

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LV JUTOMATIC TIDUL INDICATOR This purely Imerican aid to navigation automatically show's the height of the water at ny moment. When the arrows point upward the lide is rising: when downward, it is falling: The index on the scale shows that at the moment when the photograph was taken there was an excess of 1'. feet above the normal level of the water.

the process is about as follows: I party goes out in a rowboat or launch, among its members being two observers with sextants and a map showing the shoreline and the objects whose positions have been determined by triangulation; a recorder with a clock and record book; a ledsman and a steersman. The officer in charge directs the recorder to make a note of the position of the boat, which is determined by the observers, and the leadsman casts his line and calls out the depth in feet or fathoms as he draws it. up. The recorder makes a note of this and also of the course along which the boat is headed. It intervals of a minute

more the leadsman casts his lead, while every three or four minutes the observers take observations until the end

of the course is reached, where a final set of observations locate the end of the line. The boat then turns and runs other lines in the same way, until the entire bottom of the surveved area has been souded (see page 657).

The resulting figures must be corrected so that they will all apply to what is known as “mean low water.' This is fixed by taking the sum of the low-water readings for perhaps thirty days and finding their average. In fixing the depth of a sounding, the time the sounding was taken is noted and deductions or additions are made to conform with the state of the tide at that hour, as shown on the tide gauge sheets, so that all soundings are recorded on the chart as if made at “mean loy water." 011

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