box which by this time any reader, now in possession of the details of the invention, should realize is the boiler, can be enlarged indefinitely and made to cover even a mile of territory. The power possibilities of such a boiler are almost unlimited. The small hot-box that now stands in the inventor's yard, if placed in the tropics, or as far south as Miami, would produce about thirty horse-power. It is planned to locate large solar-power plants at convenient shipping points in the tropics, as, for instance, the Isthmus of Panama, the Suez Canal, Havana, Mexico and Cairo. The reasons for these projected plants reveals the wonderful scope of the invention.

For pumping water for irrigation purposes the solar engine is eminently fitted. As long as the sun shines the pumps will be in operation and whatever water is drawn from the depths of the earth will be free of cost, with the exception of lubrication, the interest on the investment and the extremely small cost of attendance. One man on horseback will be able to attend to fifty small pumping stations. It is not unlikely that our Western American desert, on which the government has already spent millions of dollars, may be made productive at a greatly lessened cost. Such intense interest has been shown by the government in this invention that the United States weather bureau has completed its plans for the erection of a plant at Washington, where private tests will be made; an Amherst college professor will take another to a high mountain range and test its efficiency, and negotiations are already under way for the operation of a trolley system by a solar plant in the land of the Pharaohs.

But there is an even larger field for the utilization of solar power and chief among these uses will be the manufacture of liquefied air. Liquefied air can be produced, Mr. Shuman claims, at a price even below one dollar per ton. Its chief usage would be for the operation of continuous expansion motors, such as steam engines. It is now being used largely in England for running automobiles and it has proved very successful. Scientists are prompt to admit that liquefied air possesses many advantages over ice for refrigerating purposes. It can now be

safely stored and shipped to great distances without serious loss.

A triple effect from liquefied air can always be obtained. In other words, the solar engine will first manufacture liquefied air; this liquefied air will be put into boilers furnished with a column-still attachment. The first run of this boiler will, naturally enough, be nitrogen. This will be diverted into gasometers after it has gone through the engine and given off its mechanical power and after it has passed through brine tanks and imparted its refrigerating properties to the artificial ice and from this nitrogen calcium cyanamide, an artificial fertilizer, can be made. The full amount of mechanical power, the full amount of refrigeration and the full amount of nitrogen can be obtained from liquefied air, the inventor claims, each without detracting from the other.

"What would be the possibilities of this invention in such cities as New York or

Chicago? What would it do in the way of mechanical power in other cities of those latitudes and climates?" he was asked.

"The temperatures of New York and Chicago differ greatly from that of New Orleans but the application of the process to those cities cannot be affected more than half by the atmospheric inequalities," was his answer.

And now, suppose a moment is given to contemplation of the changes that will have been wrought when solar-power has been developed as fully as the steam engine is at the present time. Suppose that half of the machinery in New York and Chicago and all of the machinery in the cities that are perpetually blessed with warmer climates was operated by this revolutionary power, even as engines today are driven by steam? Mankind might then begin to receive its birthright of an uncontaminated atmosphere; health and purity would once more find a foothold in the constitutions of the future generations; an infinite power would be wrested from Nature; the coal deposits of the nation that are as yet unmined would be saved for the smelting of iron and other metallurgical purposes, for which solar heat at present cannot be adapted. In the days to come it may drive the machinery of the world.

HE "sky bicycle," recently invented by Cromwell Dixon, the fourteen year old boy of Columbus, Ohio, has some remarkable features which make it well worth attention, whether or not it soon becomes a popular means of locomotion.

Young Mr. Dixon's design of airship has been tested in a number of very successful flights by the young inventor himself and has been found to work very

satisfactorily when weather conditions. were not too unfavorable. Its simplicity of construction, the ease with which it can be handled, and the fact that it is independent of mechanical power of locomotion are the points that especially commend it. As no motor is used in developing power, this feature that has proved so perplexing to most navigators of the air is eliminated from the possible sources of trouble. On the other hand it will never be of any practical utility and at the best will be little more than a toy wherewith a man may amuse himself,

as it is dependent entirely upon the foot power of the operator for its locomotion and cannot therefore be worked up to a high speed nor develop sufficient power to combat successfully against high winds or adverse currents of the air.

Instead of the gasoline motor of light weight and high power which is characteristic of the Knabenshue and other airships, Dixon resorted to a simpler solution of the power question. He merely took the gearing of an old bicycle and adapted it to his air ship. He has tested the machine in a large number of ascensions in in Columbus, Ohio, and in various other Ohio towns during the past summer and so far has had only successful trips, unmarred by a single accident. In a calm air or in a light breeze not to exceed eight miles an hour, he has been able to control the flight of his vessel at all times and to travel practically wherever he willed. With a wind higher than ten miles an hour velocity he has found consider

SAILS THE SKIES.

able trouble in beating back to his starting point. The vessel that he has used is small and lightly built, so that it offers but little resistance to the air. Whether a larger vessel, with lifting power sufficient to carry a man of normal weight could be as easily controlled is a question not yet solved.

The airship despite its simplicity of construction and the fact that it involves no new ideas is in its way a remarkable achievement, as the inventor is but fourteen years old now and was only twelve when he began experimenting two years

ago. He has figured out the perfect balance of the machine and its "boat," a portion of the work of construction in which so many would-be navigators of the air find their chief stumbling block. Two years ago Cromwell Dixon, then in the sixth grade of the Columbus public schools, witnessed a flight of Roy Knabenshue's air ship and from that time on has been working constantly in an effort. to build a similar vessel. He worked for more than a year on a motor driven boat but finally was obliged to give it up as he could not secure a motor that would work

to his satisfaction. After several disastrous attempts he finally hit upon the idea of a bicycle gear and having worked out the problem of transmitting power by means of a cog wheel arrangement attached to a propeller shaft, he attached his boat to the gas bag and in May of this year made his first flight at the Columbus driving park.

The wind was blowing about ten miles an hour, but despite the adverse currents he met with, he was able to make the circuit of the race track several times and to control the machine almost at will. His first gas bag was too small to give him the needed lifting power, so that his flights were close to the ground but this he has since remedied by increasing the capacity of the balloon.

By using a high-geared bicycle wheel he was able to develop considerable power, the wide expanse of his propeller blades assisting in this. Dixon's knowledge of mechanics was necessarily limited and he learned much as he progressed in his work. His principal ideas were obtained from studying Knabenshue's airship and he has had the aid of the Toledo man in a number of ways.

In the "boat," or canoe-like frame where the operator rides, the pedals of the bicycle gearing are attached to a ratchet wheel which in turn revolves the light steel shafting, extending through the forward part of the boat to the pro

peller in front. There are two propeller blades and, as he was obliged to reduce the number of their revolutions, Dixon increased proportionately the expanse offered to the air resistance. They measure seven feet in length by three at the flange and one and a half at the base. They revolve about two hundred times to the minute but can be sent faster if occasion demands. The steering gear is similar to that of an ordinary boat, except that Dixon uses a huge rudder operated by ropes attached to his handle bars. The cigar-shaped gas-bag is small, measuring forty-seven feet in length, seventeen feet at its center and having very blunt ends. The small size of the operator and his light weight,-about ninety pounds-requires but little lifting power.

The "boat" is an exact. model of a canoe skeleton, made of light ash strips, and permits the operator to move about in safety. It is fifteen feet long, a foot and a half deep and two feet wide at the center. The vessel is tilted from the horizontal and raised or depressed by means of sand-bags which slide along a central pole or by the operator shifting his weight. The only disadvantage of the latter is its effect on the driving

power.

Dixon is now at work on a larger vessel of similar construction which he expects will add to his fame as a successful inventor of air-ships.

-SUCKLING.

I

T is just fifty years since mountaineering became a science. First the Alps were conquered; then the Caucasus range. Gradually the Gradually the climber developed into a trained explorer and map-maker. He attacked the New Zealand peaks, the mighty Andes, and then the Ramps of Himalay," where the highest land on this planet is found. Even the central African "Mountains of the Moon," held mysterious and sacred for ages, were not exempt from invasion; and terrible Ruwenzori was conquered last year by the Duke of the Abruzzi.

Thus the Swiss pastime of Huxley and Tyndall itself became an elaborate science, as may be traced in the record of Sir William Martin Conway, greatest of living alpinists. Beginning with a traverse of the Alps from end to end, he went

on to the Karakoram Himalayas. Here he reached twenty-two thousand feet after many adventures, great outlay and much suffering. He surveyed and mapped two thousand miles of the world's mightiest range. Next came the desolate peaks of Arctic Spitbergen, and after them the towering domes of Sorata and Illimani, in the Andes of Bolivia. And lastly, Aconcagua and the glaciers of Tierra del Fuego.

This is serious work. An ascent of the Matterhorn is far from a joke-has in fact killed and maimed hundreds. Yet it is child's play compared with the conquest of Aconcagua, one of the world's giants of twenty-three thousand feet. "Nothing is so valuable to the mapmaker," says Conway, "as a panoramic view from a great mountain-top. It enables him to link together in a series of observations all other points whose positions have only been roughly deter