Page:Popular Science Monthly Volume 1.djvu/395

Rh One of the Kansas species measures 18 feet between the tips of its wings, while the expanded wings of the other would cover an expanse of 25 feet.

These animals had strong, claw-bearing digits, and a short tail, with slender heads, and teeth indicating carnivorous habits.

"We may imagine them," says Prof. Cope, "napping their leathery wings over the waves, and plunging, often seizing many an unsuspecting fish; or, soaring at a safe distance, viewing the sports and combats of the more powerful saurians of the sea. At nightfall they may have suspended themselves from cliffs by the claw-bearing fingers of their wing-limbs."

Origin of Cholera.—According to a recent paper by Mr. B. G. Jenkins, on the origin and distribution of cholera epidemics, of which Nature gives an interesting abstract, the ancients were not so far wrong, after all, in their belief that the heavenly bodies were intimately connected with the origin and course of disease. Instead of one "home" of the cholera in the delta of the Ganges, this writer holds that there are seven, all situated on or near the Tropic of Cancer. These are equally distant from each other, and, while that at the mouth of the Ganges is the most important, the others, which are to the east of China, to the north of Mecca, on the west coast of Africa, to the north of the West India Islands, to the west of Lower California, and among the Sandwich Islands, are well marked, and have all been the starting-point of "cholera-streams" 1,400 miles in breadth, which took either a northwesterly or southwesterly direction, or both. After pointing out the rise and progress of the disease within the limits of these several streams, the author mentions the curious cases of ships at sea being suddenly attacked by cholera; and again, the instances of ships sailing along the coast of India being struck by the disease when at the same place, explaining them on the supposition that the ships had been sailing within the limits of the cholera-streams; for, when they got outside the limits, the disease suddenly ceased. He called attention also to the fact that all the places recorded by Dr. Gavin Milroy as unaffected hitherto by cholera, lie outside these streams, or in their possible, but not actual, extension.

Leaving this part of the subject, he next discusses the origin of the disease, declaring that "cholera is intimately connected with auroral displays and with solar disturbances." Instancing the observed periodicity of the sun-spots, of the diurnal variation in the amount of declination of the magnetic needle, of the earth-currents, and of the aurora?, he traces a curious coincidence in the periodicity of cholera epidemics, expressing the belief that they have a period equal to a period and a half of sun-spots. He adds: "My own opinion, derived from an investigation of the subject, is that each planet, in coming to, and in going from, perihelion—more especially about the time of the equinoxes—produces a violent action upon the sun, and has a violent sympathetic action produced within itself—internally manifested by earthquakes, and externally by auroral displays and volcanic eruptions, such as that of Vesuvius at the present moment; in fact, just such an action as develops the tail of a comet when it is coming to, and going from, perihelion; and, when two or more planets happen to be coming to, or going from, perihelion at the same time, and are in, or nearly in, the same line with the sun—being, of course, nearly in the same plane—the combined violent action produces a maximum of sun-spots, and in connection with it a maximum of cholera on the earth. The number of deaths from cholera in any year for example, the deaths in Calcutta during the six years 1865-70—increased as the earth passed from perihelion, especially after March 21st, came to a minimum when it was in aphelion, and increased again when it passed to perihelion, and notably after equinoctial day; thus affording a fair test of my theory."

The Yellowstone National Park.—Interesting details of the Yellowstone National Park reservation are given by F. V. Hayden, United States Geologist, in his fifth annual report on the Geology of the Territories, just published.

By act of Congress, approved March 1, 1872, a tract of land in the Territories of Montana and Wyoming is set apart and reserved for a national park. It is situated