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 per hour. This (at fifty cents per one thousand feet) was three and a quarter cents per hour for the full running of the cooking apparatus or one and five eighths cent for cooking the entire dinner.

Turning from the domestic to the business arts, we encounter a prodigious revolution on the threshold with the incoming fuel. The gas-engine already referred to, as recently improved and extensively introduced under the German patents of Otto, supplants the steam-engine completely, on the small scale, even at the present high cost of coal-gas, and with certain other drawbacks peculiar to that somewhat tarry article. It is already available up to thirty horse-power, and at fifteen and under it is universally found a much cheaper source of power than steam, and with gas of five times the cost and much less adaptability than the American water-gas. Thousands of these engines are used in England, and in London it is expected that steam-boilers with their smoke and danger will ere long be prohibited where the gas engine is available. The "silent" gas-engines are also selling rapidly in America on the lines of rural and minor manufactures. What new stride this important substitution may take with gas at fifty cents and free of tarry ingredients, one hardly dares conjecture. But its absolute safety, automatic operation, and slight displacement, open to the gas-engine a vast sphere of common and household uses for which no motor had before been adapted. On the large scale, moreover, we may perhaps live to see such things as gas-locomotives, unburdened with coal or water, rid of their boilers, their annoying smoke, and their destructive sparks, and satisfied with picking up at intervals a plate-iron tender-car full of compressed water-gas.

In hope of closing with a sustained interest, the first actual and one of the greatest possible applications of the new gas-fuel has been left to be last mentioned—that of the manufacture of iron and steel, lately commenced in Sweden, under the American patents and the personal superintendence of a gentleman to whose inexhaustible energy and tact the American water-gas is largely indebted for its difficult yet brilliant progress—Mr. George S. Dwight, of Montclair, New Jersey.

Siemens's gas—a product saved from the combustion of coal in a furnace invented by that distinguished metallurgist—has long been used with admitted advantage in various branches of iron-working. With this well-known and standard form of gaseous fuel, Professor Moore's report, already quoted, minutely compares the American water-gas, showing that the former is many times more expensive and less efficient than the latter. In fact, water-gas made under all the old disadvantages of method is said to have been in use twenty years ago at the Oldbury furnaces near Birmingham, England, and was introduced nearly as long ago in the Yorkshire blast-furnaces. It has also been used with marked preference in France, by workers in the finer metals particularly. Of the American water-gas, Dr. Moore says that its special advantages in metallurgy are, besides its great economy in cost