Page:Popular Science Monthly Volume 2.djvu/269

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An Army of Caterpillars.—A writer in the Gardener's Monthly gives some interesting particulars concerning the habits of the caterpillars, which last spring visited the region about Memphis in such unheard-of numbers. They were so numerous, that several trains of cars coming into the city were stopped on each of the two roads, the masses covering the rails for hundreds of yards in a body, compelling the brakemen to get down and sweep them off before the driving-wheels could get sufficient hold to pass over the obstruction. They lived on the young leaves of both forest and fruit trees—the oak, quince, apple, and plum, being their favorite food. Whole orchards were denuded of foliage, and great lanes of bare trees marked their track through the forests. They are characterized by one remarkable peculiarity. Unless prowling through thick grass, or when about half grown, descending by the long web which each spins, from a tall rough forest-tree, they are always arranged in military style; and travel, also, in long, straight lines, several abreast.


Insect-Life in a Coal-Mine.—A coal-pit in England having become infested with large-winged insects, which caused the workmen considerable annoyance, by flitting around their lamps and often extinguishing them, a search was made to discover the source from which they came. The wooden props supporting the workings were found to be pierced in several places, as though by gimlets, and in the holes were found a number of moth-like insects. The wood had come from abroad, and had been in the pit some four years before the insects began to make their appearance.


An Unpatentable Pavement.—A writer in the Journal of the Society of Arts advocates the adoption of a kind of wooden pavement for the streets of London, which in point of wear he believes to be superior to all other varieties of wooden pavement, and with the additional advantage that it cannot be made the subject of a patent. He says: "Now, the only wood pavement fit to stand London traffic, and entailing the smallest cost, could not be patented by the most astute lawyer. Instead of fashioning the blocks into patent dice, hexagons, polygons, or dove-tailed complications in any form, we have only to slice barked trees of any size or quality into cylindrical slices about thirteen inches in thickness, and put the largest size down first into a good rammed foundation, and then the smaller sizes, until the remaining interstices may be filled up with what may be called pegs, the proper ramming of which will render the whole one solid mass of timber, while the economy of wood is so great that not a chip will be wasted. The surface will present end-grain only, and with the different sorts and sizes will afford a much better foothold than granite blocks."


Gold In Sea-Water.—In a series of researches on the composition of sea-water, a chemist named Sonstadt has been able to make out the presence of gold as one of its constituents. It appears to be completely dissolved, and is held in solution by the action of iodate of calcium, which, as shown by the same chemist, sea-water also contains. He demonstrates the presence of gold by three separate and entirely different methods, and estimates the proportion to be less than one grain per ton of water.



Non-inflammable Fabrics.—Cotton or linen goods may be rendered non-inflammable by being dipped in a solution of equal parts of acetate of lime and chloride of calcium dissolved in twice their weight of water.

Taper Lamp-Shades.—Dr. Minis mentions two cases in Jena and one in Frankfort where persons using green glazed paper lamp-shades were poisoned by the arsenic of the coloring matter. The heat of the lamp volatilized the arsenic, and rendered the small quantity present very dangerous.

Progress of Chemistry.—One by one the organic products are being copied in the laboratory. The last triumph in this direction which has come to our notice is the production of glycerine by Friedel and Silva. If the vapor of fusel-oil be passed through a red-hot tube, propylen is formed, which readily combines with chlorine, and from this chloride of propylen glycerine is produced by a process in which no glycerine is employed. As glycerine is the base of all true fats, this is an important step in the direction of oil-making.