peller-shaft by levers, rockshafts, and connecting rods. These, and other inventions of a high order, Ericsson described and pictured in his " Contributions to the Centennial Exhibition," published in Philadelphia, in 1876.

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During his sixty years of professional activity, the efficiency of steam engines was increased about tenfold. Toward this advance he contributed the surface-condenser, a feed-water heater, and a superheater. In addition to these original devices, wherever he came upon good practice he carried it a step further. He adopted and improved artificial draft, the expansion of steam in two cylinders instead of one; and, well aware of the great economy of high pressures, he employed steam at 225 pounds per square inch when 100 pounds were deemed the limit of safe working. With metals and alloys of new strength, with machinetools of heightened power and precision, he saw that new gifts were proffered to engine builders. He grasped them with boldness and success.

From Ericsson, the engineer, let us turn to Ericsson, the Swede. Once, in writing to the Royal Librarian at Stockholm, he said: "I know but one fatherland: I would rather that my ashes reposed under a heap of cinders there, than under the stateliest monument in America."

And Sweden requited his fealty with every honor in her gift. In 1852, he was made a Knight of the Order of Vasa. In 1866, an industrial exhibition was held in Stockholm, to which the great inventor was invited in the most cordial terms by the Crown Prince, afterward King Oscar II. His invitation, with equal cordiality, Ericsson declined on the score of pressing engagements from which he could not free himself. The next year his old neighbors of Filipstad paid him a compliment which touched him to the heart. On September 3d they unveiled at Langbanshyttan, a superb shaft of granite, pyramidal in form, 18 feet high, and 8 feet square at the base, inscribed:

JOHN ERICSSON

was born here

on the 31st of July, 1803.

There was a characteristic word in the letter of acknowledgment which he sent through his friend, Commander A. Aldersparre:

It is with great pleasure I find that, at the dedication of the monument at Langbanshyttan, my former playfellow, Jonas Olsson, now foreman at the iron foundry, was present. This honorable man must have a souvenir from me. Will you excuse me troubling you again? I inclose a check for five hundred crowns ($140), and would you please for that sum buy a gold watch and have engraved on the inside, To Jonas Olsson from his playmate, John Ericsson,' and then have it delivered to the honest workman. Could this be done through my friend Gustaf Ekman and with a little ceremony, I would be pleased."

In 1867, when a terrible famine prevailed in large areas of his native land, Ericsson sent $5,600 to Norrland, for the purchase of grain best adapted to its soil. Says his biographer, Mr. Church: "A Swedish traveler, who visited him at this time, tells how his voice choked, and tears filled his eyes as he spoke of the distress in his native land. He said: 'Let us not be content with assurances that life can be sustained on herbs not intended by Nature for the food of human beings. Bags of meal will be more welcome among the unfortunates than good advice as to gathering coral-moss for winter food.'"

Until his mother's death, in 1853, news from Sweden came to Ericsson chiefly through her letters. He loved his mother with all his heart. When nothing else could tempt him from his drawing-board he would turn aside. long enough to respond to a word from her; and his responses usually included remittances for her comfort. To

his sister in Sweden, Mrs. Odner, Ericsson gave a commodious house, and the proceeds of his Swedish patent for the caloric engine, yielding a considerable yearly income. On October 25, 1870, in a letter to his nephew, John, he said: "The news that I no longer have a brother was, indeed, a severe blow; it pained me all the more as I had received only a fortnight before information that my sister had been laid in her grave. The thought of their sufferings presents itself constantly to me, and is in the highest degree painful." Ericsson gave largely and constantly to impoverished relations and friends, and to public objects. Yet his bestowals did not denote mere pecuniary incontinence: he carefully considered the justice of each claim, and his gifts were bestowed with sound judgment.

In 1868, the. University of Lund, in celebrating its second centenary, extended a hearty invitation to Ericsson. He could not attend, but he honored the occasion by sending a thesis on solar heat as a source of motive-power. His paper recounted experiments in which solar rays falling upon a surface ten feet square had been concentrated by reflectors, so as to evaporate 69 cubic inches of water in an hour, and generate by steam one horse-power. The University, in acknowledgment, gave him a degree as Doctor of Philosophy.

He constructed his first solar motor in 1870, and intended it to be a gift to the Academy of Sciences in France. As incidentally it registered the amount of steam generated, friction was minimized to the utmost in its design. The sun's rays were focused upon a cylindrical heater, placed lengthwise above a reflector shaped like a trough. Ericsson believed that motors on this model would have great value in regions where solar heat is intense, and where sunshine is seldom obscured by clouds. He said:

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Experiments show that my mechanism abstracts on an average, during nine hours a day, for all latitudes between

the equator and 45 degrees, fully 3.5 units of heat per minute for each square foot presented perpendicularly to the sun's rays. A unit of heat equals 772 foot-pounds, so that,

theoretically, energy of 2,702 foot-pounds is transmitted by the radiant heat per minute for each square foot, or 270,200 foot-pounds for ten feet square, or 8.2 horse-power. But engineers are well aware that the whole dynamic energy of

heat cannot be utilized in any engine whatever. Hence I assume that but one horse-power will be developed by the solar heat falling upon an area ten feet square within the latitudes mentioned."

From time to time during the remainder of his life he busied himself with this motor and with the storage of its motive-power. When he compressed air for this purpose, he found that he had to employ a reservoir of undue bulk. It may be that the electrical storage battery will prove to be the desideratum here. But before the sun in its direct beams replaces fuels in which its rays are indirectly stored, coal, peat, and wood will have to be much dearer than they are to-day. Heat engines of modern types not only show a high economy, but that economy is steadily rising, while their exhausts are now much more widely utilized for heating and manufacturing than ever before. But Ericsson's labor, as he improved his solar engine, was not barren. It brought him to principles of construction which, adapted to his hot-air engine, conferred a new effectiveness upon that motor. In its improved design it was built by thousands by the Delamaters for a profitable sale. Strange to say, Ericsson never patented this engine, his most lucrative invention. For sixteen years Mr. Alfred W. Raynal was superintendent of the Delamater Works. He has said: "The chief characteristic of Ericsson was nobility of soul. He had genius of the first order, and under a grim exterior he had a heart of gold. A workman, Bernard Sweeney, whom he liked, fell ill and died. Ericsson ordered the Works to be closed on the day of the funeral, that all who wished might attend. He cheerfully paid more than a thousand dollars as the wages involved in this tribute of respect."

And now it is fitting, as this sketch draws to a close, that a word be said about the homes of Ericsson in New York. In 1843, he removed from the Astor House, where he had