Sixty-five years later, in 1735, Père Galien, of Avignon, gave a fairly clear expression to the theory of aërostats. Resting on the principle of Archimedes, he maintained that if he could fill a globe made of light cloth with a sufficiently rarefied air the globe would necessarily possess an ascensional force, which would permit it to lift itself up in the air with a ship and all its cargo. He proposed to draw this rarefied air from out of the upper regions of the atmosphere, down from the summits of high mountains, forgetting that the air, when brought down to the level of the ground, would contract in volume and assume the density of the ambient atmosphere.
In the condition of ignorance of the properties of gases that existed in that age, it did not occur, and could not have occurred, to Père Galien to use other gases than air; no more could he have thought of employing heat to rarefy the air, for the first not very precise notions on the decrease in densities of gases by heat only date from Priestley. But when Cavendish, in 1765, had fully studied hydrogen gas, and shown that as it was prepared then it was seven times lighter than air, Black was enabled to suggest that by filling a light bag with hydrogen the bag would be able to raise a certain weight in the air. The labors of Cavendish, Black, and the discoveries of oxygen, nitrogen, and other gases by Priestley, were described by Priestley a few years afterward in the celebrated book on The Different Kinds of Air—a book which Stephen and Joseph Montgolfier had in their possession. The two brothers evidently found the germ of their invention in it.
It is fair to say that the Montgolfiers, who were already known in the learned world by their discoveries in the mechanical sciences, had thought, before they knew of Priestley's book, of a way of imitating Nature by inclosing vapor of water, a gas lighter than air, in a paper bag, which would be lifted up, the vapor contained in the bag being sustained in the air like a cloud. But the vapor condensed, and the weighted balloon shortly fell to the ground. The smoke produced by burning wood inclosed in a bag gave no better results. After seeing Priestley's book, they substituted hydrogen for vapor and for smoke, but the gas passed through the paper bag, and they gave up this attempt.
They then fancied that electricity was one of the causes of the rise of clouds, and sought for a gas that had electrical properties. They thought they could obtain it by burning wet straw and wool together. A box made of silk was filled with this gas, and they had the great satisfaction of seeing it rise to the ceiling of their room, and, in a second experiment, into the air. This was in November, 1782.
Five months previously, Tiberius Cavallo, in England, had repeated Black's experiment of filling a paper sack with hydrogen; but, as the Montgolfiers had found, the hydrogen leaked through the paper. Cavallo had better success with soap bubbles, which held the gas. His experiments stopped here, while the Montgolfiers carried theirs on to practical success.—Translated for the Popular Science Monthly from the Revue Scientifique.
SKETCH OF EDWARD ORTON,
LATE STATE GEOLOGIST OF OHIO; LATE PRESIDENT OF THE AMERICAN ASSOCIATION FOR THE ADVANCEMENT OF SCIENCE.
All persons interested in American science were surprised and shocked at learning of the death, from heart trouble, on October 16, 1899, of Prof. Edward Orton, of the Ohio State University. The event occurred only little less than two months after Professor Orton had presided, with a simplicity of manner that did not hide but rather heightened the traits of vigor in his character, over the meeting of the American Association for the Advancement of Science at his home in Columbus, Ohio. The services he rendered to geology, his long and honorable career as an educator, and his continual and consistent insistence upon the faithful use of the scientific method well entitle him to be remembered as one of the most meritorious of American scientific workers.
Edward Orton was born in Deposit, Delaware County, N. Y., March 9, 1829. He was descended from Thomas Orton, who, born in England in 1613, was one of the fifty-three original settlers and owners of Farmington, Conn., was of the stock from which most of the Ortons in the United States are derived, and represented his town in the General Court in 1784. Another ancestor, a grandson of Thomas Orton, was one of the original purchasers and settlers of Litchfield, Conn., where he owned a square mile of land known as Orton Hill, on the south side of Bantam Lake. Two of the maternal ancestors of the subject of this sketch fought in the colonial wars, and ten Ortons were soldiers in the Revolution.