Page:Popular Science Monthly Volume 12.djvu/656

638 they now are." The different kinds of fish now in these ponds are California salmon, Kennebec salmon, brook-trout, salmon-trout, grayling, a hybrid of California salmon and brook-trout, also a hybrid between salmon-trout and white-fish.

Graves of the Mound-Builders.—On opening a sepulchral mound on Coup's Creek, Macoupin County, Illinois, four skeletons were found sitting two-and-two, with the arms crossed, and the knees of one pair pressing sharply against the backs of the other. The grave was six feet in length by three in width, and search was made for other remains. Nothing, however, was found, except four large marine shells, identified as of the Linnæan species Busycon perversum. The position of each of these shells in relation to the skeletons was the same: the smaller end of one had been placed in the right hand of each, while the larger portion rested in the hollow above the left hip. But what will appear most singular in this remarkable find is the fact that each shell contained what seemed to be the bones of an infant. "Within each of the shells," writes Mr. John Ford, in the "Proceedings" of the Academy of Natural Sciences of Philadelphia, "there had been packed what appeared to be the bones of a child; the skull, which evidently had been crushed before burial, protruding beyond the aperture. Of course, any hypothesis regarding the purpose of this peculiar rite must necessarily be of a conjectural character; nevertheless, it was difficult to resist the conclusion that these infants were sacrificial offerings to the spirits of the dead, whom the living desired to honor."

Non-Poisonous Coloring for Preserved Vegetables.—A patented process, for giving to cooked and preserved vegetables a green color, without the employment of copper or any other poisonous substance, is described as follows: First, the green leaves of some such plant as spinach, or sorrel, are scalded for a few minutes with boiling water, and drained; they are then triturated with knives or other cutting instruments. Next the triturated mass is heated with an equal weight of caustic soda solution marking 12.5° Beaumé, the mixture being boiled till the leaves are dissolved. From the product prepare a "lacker" by precipitating alum with this alkaline solution of chlorophyl, and then draw off and wash the precipitate in abundance of water, and finally press out the excess of water. To prepare the lacker for use, about thirty pounds of it is put in a basin with about fifteen pounds of soluble phosphates, especially phosphates of soda, potash, or ammonia, or of acid phosphates, or alkaline citrates, or double tartrates, and water is added until the liquor marks 2° to 5° Beaumé. To communicate the green color of this chlorophyl preparation to cooked or preserved vegetables, the latter have only to be immersed for a few minutes in the solution at a temperature of 212° Fahr. The effect of the operation is to impart to the products treated a fine, permanent green color, due to the absorption and fixation of an excess of chlorophyl.

Compressed Air in Coal-Mining.—An English journal gives an account of certain experiments recently made at Wigan to show how compressed air may be substituted for fiery explosives in coal-mining. A "cartridge," or reservoir, was placed in a shot-hole, after the manner of a charge of powder, and rammed or plugged in the same way. This chamber is in connection with a powerful air-pump, adapted expressly for the purpose, and, by simply turning a wheel, the collier can "fire his shot" without the least danger of setting fire to the inflammable gases. Mr. Marsh's (the inventor's) machine is capable of exerting a pressure of over 12,000 pounds to the square inch, and this force can be produced by two men turning the wheel in less than three minutes from the time of ramming the cartridge. The Wigan experiments show that very large quantities of coal can be brought down at a very much less expenditure of force. The first cartridge "fired" was burst at a pressure of 7,500 pounds to the square inch, the pressure being registered by a gauge. The coal was fractured, but not brought down; and a second cartridge was inserted, and burst at a pressure of 8,250 pounds to the square inch, completely loosening the coal and breaking up about eight tons. The whole force of the shot was probably not exerted on the seam, as