with two soluble substances which, coming together, will form an insoluble one. If wood is impregnated, too, with a substance capable of volatilization, its taking fire will be delayed till the volatile substance has been driven off. Warning of fires is automatically and surely given by means of devices by which the expansion of a column of mercury by the developed heat is made to close the circuit of a galvanic battery and sound an electric bell.
The Sunny Skies of Kamchatka.— M. Leonhard Stejneger has published in the Norwegian journal, "Naturen," a paper on the fauna and flora of Eastern Kamchatka and the Commander Islands, which adjoin our own Aleutian Islands. While the climate of the islands is foggy and their vegetation scanty, Kamchatka is represented as rejoicing in Italian skies, smooth seas, and a mild temperature. The flora is so exuberant that some species, which only grow to be three feet high in Norway, there attain the height of a man. Among them are the birch, alder, willow, and service-tree, whose berries as well as those of a honey-suckle are finely flavored, and well relished by the inhabitants. The flowers of the wild rose, rhododendron, potentillas, and taraxacum, might be mistaken for Norwegian species. The birds are also well represented, and one of them, a warbler, is distinguished by a plumage that suggests the tropics, and a voice comparable with that of the nightingale. The fauna is generally palæ-Arctic, and few American forms are found.
Mr. James Stevenson, of the United States Geological Survey, has discovered some new cave and cliff cities in which a few peculiar features have been observed. One of them is a village of sixty-five underground dwellings situated near the top of one of the volcanic foot-hills of the San Francisco Mountains in Arizona. A common roof was furnished for the whole community by the hardened surface stratum of the hill.
Mr. Herbert McLeod has determined, by experiments instituted for the purpose, that India-rubber is altered under the combined influence of light and oxygen—absorbing oxygen and becoming cracked—but not by either agent alone.
Last year included the fiftieth anniversary of the lucifer-match, which was first made, in England, by John Walker, of Stockton-on-Tees, and also at Vienna, in 1833. In 1847 the red amorphous phosphorus was substituted for the more dangerous, corroding, ordinary phosphorus.
Professor Cohn has called attention to the fact that bacteria were first seen two hundred years ago, by the Dutch microscopist, Leeuwenhoek, who, in 1683, gave to the Royal Society a description of "very little animals moving in a very lively fashion," which he had detected, with his instrument, in the white substance adhering to his teeth. His drawings are very correct, and have never been surpassed till within the last ten years.
Captain T. G. Een, a well-known Swedish explorer, died from heart-disease on the Congo, while on his way to join Mr. Stanley.
M. Fayal, directing engineer of the coal-mines of Commentry, France, has published an account of his discovery of coal at that place, which has preserved to the very center of the beds the histological structure of the plants from which it is formed. The preservation is said to have been so distinct that M. Renault has been able to make specific determinations of several species of the carbonized plants.
A great impulse has been given to fruit-growing within the last ten years. The area of land devoted to this purpose in England increased, between 1872 and 1882, 26,696 acres; while the importations of fruit from different countries increased from 1,218,668 bushels in 1871 to 4,045,690 bushels in 1882. Much of this fruit is used for making jam. The acreage of fruit-land in Canada has been largely extended within the last fifteen years, and great interest in the promotion of the industry is taken by the Government and the land-owners. In the United States, two million acres were under cultivation as apple-orchards in 1878, and the value of the products had increased in twenty years from $6,600,000 to over $50,000,000. The drying and the canning of fruits have become very prominent branches of industry.
The author of the work on "World-Life," recently reviewed in our pages, regrets that the book contains a number of errata, and desires us to announce that slips of corrections will be mailed to any who will kindly signify their desire to receive them. Address Alexander Winchell, Ann Arbor, Michigan.M. Arthur Roche, Professor in the Lycée of Montpellier, France, who died a few months ago, was well known for his researches on the figures of planets and