the work because of the treacherous nature of the earth which caved in continually. It was like digging in thick soup, and the tilelayer was forced from the shoe many times a day while the whole crew waited for the water to drain away. The cost was over $2,500 but the job was a success. The land cost the speculator a little over a thousand dollars and, planted to milo maize, it sold for $15,500.

As is usual with anything new, the legitimate farmers who really need the benefit of his knowledge seldom apply to the engineer. The greater part of his work has been done for men like this speculator, who are harvesting the dol

lars while they may. Now, however, that some one else has shown the way, the land owners are beginning to realize what a big proposition they have. Their alkalied flats and salt-grass bottoms are likely to make them rich. At no cost to the ranchman the government will show him how to raise crops where he thought crops would never grow, and more than that the government will detail a competent man to boss the job and see that the washing is properly and thoroughly done. And the ranchman forgets about state's rights and public domain and shouts for "new nationalism" and the development of our natural resources. His point of view is changed. .

Great Talkers, Little Doers.

Tongue double, brings trouble.

W

HY is the glacier?

It is a question that has been asked ever since men first stood at the face of one of the great ice-fields, that claws its irresistible furrow across the earth's tortured surface, and wondered. Most overwhelming of the agents that change the face of things terrestrial from age to age, it has been least understood by humans because its secrets have lain hidden beneath the immensity of Nature's own endless patience, and our observation has been unable to grasp them from the centuryslow signs that have come to the surface. What causes glacial epochs or ice ages? How often do they occur? What sets a glacier in motion? What causes a glacier to cease to move? What causes a glacier to travel up an incline? What are the relations of glaciers to ice-bergs

in a glaciated area? What are the relations of glaciers to stationary ice-fields? How is loess deposited? Why the irregular distribution of bowlders or "lost rocks"? Why are these bowlders more abundant along certain lines?

These and scores of similar questions occur to the inquiring mind. And the answers to some of these questions are not to be found in any text-book, encyclopedia or other publication.

The writer has spent weeks on the glaciers-and months in the ice-fields— of Alaska. Observations were made in that country that will enable us to add a few facts to the world's stock of information on these and kindred subjects.

The cause of glacial epochs is undoubtedly the change in the inclination of the axis of the earth to the plane of its ecliptic, or pathway through space. At the end of an astronomical year the

center of the earth is at the same point in space that it occupied at the end of each preceding year. But the angle described by the earth's axis and its ecliptic has increased in one hemisphere and decreased in the other. This change in the direction described by the earth's axis brings one hemisphere towards the sun, and gives it a warmer climate. This change also turns the opposite hemisphere away from the sun, and causes it to have a colder climate-to become more or less glaciated. Thus one hemisphere is constantly passing through a glacial epoch, or ice age. At the present time the Southern hemisphere is much more highly glaciated than is the Northern hemisphere. But let it be remembered that there is always at least some ice near the poles-inside the Arctic and Antarctic Circles. During these glacial epochs the ice travels about

'A

D

one feet in one year. There is a corresponding change in the location of the equator and the other great circles of the earth.

What sets a glacier in motion?

Snow under pressure becomes ice. A mountain of ice accumulates bulk and height until the pressure at its bottom generates heat. Calculating ice at eighttenths the weight of water, the pressures at the bottoms of glaciers would be as follows: a glacier 2,000 feet high, 695 pounds to the square inch; 3,000 feet high, 1,043 pounds; 4,000 feet high, 1,390 pounds, and 5,000 feet high, 1,738

one-half of the way from the poles to the equator-in some instances sixtenths of the distance, or to the thirtysixth parallel of north and south latitude. How often do glacial epochs occur?

Astronomers have calculated the annual change of the inclination of the earth's axis to be a little less than threetenths of one second, circular measure.

This change of inclination continues until the described angle increases to twenty-three and one-half degrees or to the Arctic and Antarctic Circles-and then the change is in the opposite direction. Twenty-three and one-half degrees equal 84,600 seconds. And 84,600 divided by three-tenths equal 282,000. The glacial epochs, on this hypothesis, can not be closer together than 282,000 years.

The last glacial epoch in the Northern hemisphere commenced about 241,000 years ago and ended about 80,000 years ago, an estimated cycle of about 321,000 years.

The change in this angle of inclination is sufficient to change the location of the poles between thirty and thirty

pounds to the square inch. Whenever a mountain becomes high enough, from the accumulation of snow on its top, to cause the pressure at its base to generate heat sufficient to raise the temperature to the melting point, water then commences to accumu

late beneath the huge mass.

This water must escape-have vent. How? Where? On the side next the sun-for the opposite side is much colder, and is closed by frosts.

A number of small streams originate under an ice-mountain. But they gradually merge, and form one large stream. The erosion of the outflowing water on the sunny side of an ice-mountain lowers the surface of the earth on that side. The mountain topples in that direction. Naturally the melting on the sunny side is much more rapid than on the opposite side. So the melting assists in inclining the mountain in that direction. Finally it commences to move down this eroded incline, and becomes an active glacier.

As soon as motion is set up the earth on the sides bulges or buckles up, from the immense pressure and momentum, and forms lateral moraines, or longitudinal ridges, that are outside of the base of the glacier and that parallel its axis. These lateral moraines form a trough which confines the water under the glacier in a continuous stream that

flows in the direction towards which the glacier travels.

Of

Once in motion a glacier will continue to travel until conditions change. course if it travels down an incline, its motion may be largely from force of gravity. It is probable that all of the glaciers of Europe, at the present time, are gravity glaciers.

What causes a glacier to cease its motion?

There are at least three causes: (a) the underflowing stream may break through a lateral moraine and escape at one side instead of in front of the glacier. This change in the underflowing stream will leave the glacier "dead"; (b) the glacier may encounter a mountain wall or other obstacle that it can not surmount nor break down, or (c) the immense weight of the glacier, with the rapid lowering in front, as already described, may cause its nose to plow into the earth deep enough to prevent motion. When this last cause operates, motion is usually but temporarily arrested; for the underflowing stream may erode the terminal, or front, moraine until the glacier is enabled to pursue its original course.

When the underflowing stream breaks

through a lateral moraine, and the glacier above ceases to move, the erosion ceases in front and increases under the body of the glacier. This under erosion will finally cause the glacier to break in two. By this time the escaping stream has eroded an incline on the side of the glacier down which one piece, or section, of the glacier may take motion at an angle of from forty to ninety degrees from the original line of motion.

What causes a glacier to move up an incline?

Glaciers have traveled from the far North to near the thirty-sixth parallel of North Latitude. They have crossed hills. -even mountains. Sometimes they have plowed through mountain ranges, as has the Muir glacier in Alaska. It has cut through a mountain that is at least 3,000 feet high.

Leaving out of consideration a discussion of the explanation of gravity, we may regard the phenomenon from the side of effects only. And so far as effects are concerned, the motion, or cause of motion, of a gravity glacier is easily understood. But what causes operate to propel a glacier up an incline? When water is at a temperature of

about thirty-nine degrees above zero, Fahrenheit, it is at its greatest densityoccupies the least space. The higher it is heated the more it expands; and a piece of ice is much larger at a temperature of 60 degrees below zero than is a piece of the same weight at a temperature of thirty degrees above zero.

The bases of all active glaciers have a temperature of about thirty-four degrees or two degrees above the freezing point. This is why there is always an underflowing stream. With a temperature of thirty-four degrees above zero at the base and sixty degrees below zero on top, there would be a difference in temperature of ninety-four degrees sufficient to cause a top expansion of fourteen per cent, or 280 feet in a glacier 2,000 feet high; 420 feet in a glacier 3,000 feet high; 560 in one 4,000 feet high, and 700 feet in a glacier 5,000 feet high. It is evident that a face of ice will not stand at this angle of projection; so a large, prismatic, or rhomboidal, section breaks off and falls forward.

The underflowing stream is confined by the lateral moraines on the sides, by the glacier above and the earth beneath it. When the rear end of the glacier is higher than the front this stream works under hydraulic pressure. But, at all times, the action of hydrostatic pressure is persistently driving the water forward

with great force-from beneath the glacier.

When the water rushes from beneath a glacier it encounters the detritus of ice that has fallen from its front face. The pressure forces the water forward and upward between the face of the glacier and the detached pieces. Thus is the lower front of the glacier altered by three processes: by the attrition of the outrushing water; by melting which is caused by the higher temperature created by the water, and by the absorption of water which raises the temperature, and thus contracts the mass-reduces the size-of all the ice penetrated by this extraneous moisture. So these three processes augment the force of expansion in the work of causing the front face of a glacier to project forward.

When a large section of ice falls forward, as already described, it is quickly submerged-or partly submerged-by the outrushing water. The portion under water rises in temperature while the portion in the air remains much colder. This difference in temperature causes a secondary breaking and falling forward of pieces that constituted the original, large detached section. These secondary fragments freeze together at, and immediately below, the water line. So when a piece drops forward it draws or drags the piece immediately behind it until the frozen bond at the water line is severed. This constant dropping forward, and dragging of pieces from behind, enables a glacier to move piecemeal up an incline. As soon as a glacier, that has thus reached a summit, starts down an incline again the immense pressure from behind soon unites the parts into a comparatively solid mass once

more.

Of course the element of expansion is indirectly attributable to the sun-the source of all terrestrial heat. But a second cause of motion in glaciers is the direct force of the sun. Place a piece of ice on a