head of the population; for Switzerland, 24; Germany 15; France 10. Turkey figures for only 0·2 of a letter per capita. In America the number of letters and postal cards carried was 700,000,000; in Asia, 150,000,000; in Australia, 50,000,000; in Africa, 25,000,000.
Gas-Stoves and the Products of Combustion.—City people are wont to express their surprise at the stupidity of the countryman who extinguishes a gaslight by blowing it out, and then sleeps in the same room. Yet the same acute city people will set up a gas cooking-stove, and will never think of the necessity of carrying away the products of combustion. Plainly, in view of the prospective large employment of carburetted hydrogen gas as a domestic fuel, it behooves the sanitarian to emphasize the necessity of proper regard for sanitary requirements. The public will have to be instructed in the simplest elements of science, and drilled to heed the plainest teachings of every-day experience, or else the general introduction of gas as a fuel will at first occasion a fearful amount of mortality. The observations of the editor of the "Lancet," in a house in the "West End" of London—the fashionable quarter of that metropolis—might be repeated any day in the "best quarter" of our American cities. The editor of the "Lancet" visited the kitchen of the house in question, having been asked to give an opinion as to the wholesomeness or otherwise of the cooking arrangements. He found a gas hot-plate with five circles of burners, each circle having 12 or 15 jets, so that when the hot-plate was fully heated 60 or 80 jets were in active combustion. Each jet produced about two cubic feet of carbonic acid per hour, a total of 120 to 160 cubic feet, in addition to sulphurous acid. No chimney was provided for the escape of the gas, and the very intelligent inmates of the house could not understand why the cook looked so pale and ill; as for the cook herself, though she often felt "giddy and fit to fall upon the floor," she never suspected the gas-stove! Now, since each of the gas-jets had an effect equal to the respiration of one human being, it is evident that the population of that kitchen practically amounted at certain times to sixty or eighty persons; and the exhalations from this "black hole" had no way of escape except through the kitchen door and into the house. This instance of the stupidity of "intelligent" people is so typical that it deserves to become "classic."
Effects of a Diet of Shingle-Nails.—The cows of a large dairy-farm in Hungary having been all simultaneously seized with disease, the symptoms being high fever, difficult respiration, and inflation of the body, it was determined to slaughter two of them and to make an examination of the bodies. The organs of the chest appeared perfectly normal. On opening the stomach its contents were found partly fluid and partly of pappy consistence, and among this matter were discovered a number of shingle-nails of various lengths, some of them free, and others partially imbedded in the walls of the stomach. Renewed investigation cleared up the mystery as to how these nails got there. About a year before, a shed on the estate caught fire, and the shingles of the roof were torn off, nails and all, in the attempt to put out the flames. In the winter the damaged materials were burned in the farm-buildings as fire-wood, the ashes subsequently strewed upon a clover-field, and the nails contained in the latter unfortunately were raked up with the hay crop obtained from it in the following summer. Every cow upon the farm had to be slaughtered, and in every case nails were found in the second stomach.
The Electric Light as a Source of Nitric Acid.—It is known that, when combustion takes place at high temperatures, small quantities of the nitrogen and oxygen of atmospheric air combine, forming several oxides of nitrogen, many of which are strong, corrosive acids. This is the case when electric sparks are passed through air, also during combustion in air of hydrogen. It therefore appears probable that, as the temperature of the electric arc is undoubtedly very high, nitric acid, or some other oxide of nitrogen, might be produced by the electric light. This subject has been investigated experimentally by Mr. T. Wills, with results strongly confirmatory of this theo-