THE POPULAR SCIENCE MONTHLY.
hot water, or by scraping. Such filters, singly or in numbers, are placed in the bottom of a cistern, the central pipes of efflux being all connected together, and with one outlet. Where a large filtering capacity is required, a different principle is adopted, viz., a series of carbon-plates. In this case the water, in its passage from the inlet to the outlet, is caused to pass through a number of frames, variously constructed, according to circumstances. Thus there may be, firstly, a frame, covered with fine wire gauze; then separate frames, paneled with carbon-plates, with or without the intervention of a bed of pure loose animal charcoal, filling up the spaces between them; and there may be also a double frame, containing a sheet of felt compressed between two perforated plates, made respectively of sheet-copper and zinc, which would exert a certain electrical action, and aid in the chemical action of precipitating impurities. The system may be used for filtering the water-supply of a town.
Apart from this hygienic use, these carbon-blocks may be employed for many industrial purposes. Experiments have shown them to be efficacious in removing deleterious gases, and other soluble substances held in solution in fluids. They are applied as filters for wines, oils, and syrups; and, above all, they merit attention as an adjunct to the feed-water apparatus of steam-boilers, inasmuch as efficient filtration affords the best, cheapest, and surest method for preventing incrustation in boilers.
Cremation.—An eccentric will, wherein the testator requested that his body might be consumed in a gas-retort, and thus made to contribute to the enlightenment instead of the poisoning of the world, has survived the long-forgotten subject of cremation. Without doubt, Mr. Trelawney's hideously-graphic description of the burning of the body of Shelley has greatly contributed to prejudice the public mind against the cleanest and best method of getting rid of the "mortal coil." But the ceremony at Spezzia was conducted in the most bungling fashion, and a want of scientific appliances contributed to the incompleteness, and, therefore, to the horror of a simple operation. A retort gets rid of the entire difficulty, and, both from a utilitarian, a scientific, a sanitary, and a poetic point of view, the mausoleum, decked with cinerary urns, possesses immense advantages over the damp and unwholesome graveyard, exhaling pestiferous odors, to which modern nations, for some inscrutable reason, are preposterously wedded.—Iron
Death of Dr. Forbes Winslow.—Dr. Winslow was born in London in 1810. He began his medical studies in New York; took the degree of M. D. at King's College, Aberdeen, and became a member of the Royal College of Surgeons, London, in 1835. His first published works appeared in 1831, since which time he has made numerous important contributions to the literature of medicine, chiefly in the department of nervous and mental diseases. His most valuable work in this line, "The Obscure Diseases of the Brain, and Disorders of the Mind," was published in 1860, and has since passed through several editions. He died in London, on March 4, 1874.
The Economy of Beer.—Prof. Max von Pettenkofer, the eminent Munich chemist, states that, to make a quart of good beer, there is required, at least, a pint of good barley, besides hops, etc. The product contains not a single trace of albumen, and only a very small percentage of alimentary principles: in short, it is only a condiment, not a food-stuff properly so called. The question now arises, Would it not be better to send this barley to the mill, and make of it a bread-stuff, instead of brewing from it a costly beverage, which contributes little or nothing to the system? Or, better still, Would it not be advisable to grow, in place of barley and hops, wheat and rye, either of which would give better bread than barley?
Prof. Pettenkofer holds that the need of mere condiments is no less imperative than the need of food-stuffs, properly so called. "Butter and cheese," says he, "are neither as good nor as complete foodstuffs as milk, and yet butter and cheese are made, and will continue to be made, even though it were possible to transport milk in good condition to considerable distances." The same is to be said of barley and beer. Prof. Pettenkofer observes that