perature of the mixing materials the work could have been continued in even colder weather," said one of the Newtons, "but it would have been too hard on the tower men."

Working on an open frame steel tower in fifteen below zero weather calls for a good constitution and plenty of warm. clothing. The tower men, one of whom was stationed above the hopper near the top of the tower, cleans the hoisting bucket each time, and another, on a platform a little lower down, operates the hopper gate and lets the concrete discharge into the pipe line. These workers were bundled in hooded sweaters, canvas wool-lined coats, heavy pants, leggings, socks and shoes. During the coldest weather a canvas screen was thrown around the lower part of the tower for some slight protection at least against

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the bitter wind which swept down the icy river.

The bottom of the stream or rock on which the work was built was all the way from eight to twenty feet below the water level held back of the cofferdams. The method of handling the water was as follows: as the rock was excavated from the canal it was dumped to form a stone embankment extending out over half across the river from the Michigan shore.

Such leakage as came through this embankment or first line of defense was stopped and diverted by a second line formed of wood sheet piling driven to bottom and made watertight. Water was removed from the cofferdams by pumping and also by the use of a twelve-inch siphon, which, when started, ran uninterruptedly with little attention.

F

ROM this time on, every farmer who so desires may have an independent gas plant of his own, to illuminate his house and furnish fuel for cooking. The convenience, even in remote rural districts, will cost no more than people ordinarily pay for gas; and it goes without saying that the same opportunity offers itself to the suburban dweller, if his immediate neighborhood be not already piped by a lighting company.

There are, indeed, many instances where residents of cities would be glad to gain freedom from the autocratic gas companies. And it is wholly in their power to do this by making use of the new "liquid gas," which is beginning to come on the market, being supplied in steel bottles-the latter refilled as often as may be requisite. Such a bottle, fiftytwo inches long and eight and a half

inches in diameter, weighs only forty pounds, and holds enough of the stuff to last an ordinary household for a month.

There is no secrecy about the method whereby the liquid gas is produced, and before long it will doubtless be manufactured in enormous quantities — the source from which it is obtained being a waste product of the petroleum wells. The process involved was invented by Walter O. Snelling, a young scientist attached to the Pittsburgh laboratory of the government Bureau of Mines. He claims that the gas is equal in quality to any illuminating gas, while much less explosive than the kind derived from coal. It gives five times as much light as the latter, and has more than four times the heating value per cubic foot.

It should be understood that natural gas is of two kinds-(1) "dry gas,' which is the familiar natural gas of com

merce, and (2) a gas containing easily liquefiable vapors, known in the vicinity of oil fields as "heavy," or "wet," gas. From the latter is obtained the liquid gas here described the readiest source being the waste gas which accumulates in the pipes of oil wells. This raw product is a material for which no use has hitherto been known.

The liquid gas, separated out by a somewhat complex chemical process, is a perfectly transparent fluid. It remains in liquid form. when under a pressure of five hundred pounds to the square inch, but under less pressure it volatilizes, changing to gas. One volume of the liquid produces four hundred volumes of gas, and each volume of the latter is equal to four volumes of gas made from coal. Hence it follows that one volume of the liquid is equal to sixteen hundred volumes of ordinary illuminating gas.

The stuff is very clean and pure, and can be handled in the same way as ordinary gas for lighting. By the help of a "reducing valve," the liquid from the bottle changes to gas at a pressure just about equal to that used in the present system of house illumination. No special apparatus of any sort is needed, except the bottle-with its valve attachment-which is placed against the side of the house out of doors, in a convenient sheltered position.

All of the fixtures that are used with the ordinary illuminating gas are used with the liquid gas-the highest economy in its employment being attained with inverted burners and incandescent mantles of the familiar kind. Burners of this type are specially adapted for a gas of such high heating value, and a much smaller mantle gives a

far brighter and steadier light than coal gas yields.

In the country home liquid gas can be used to exceptional advantage for cooking, by reason of its great heating power. Being equally available for operating instantaneous water heaters, it will give to the farmhouse this much-esteemed convenience of the city dwelling. The supply is made reliable and continuous by replacing the steel bottles at regular intervals, a reserve cylinder being always kept on hand for possible emergency.

It is suggested that tank cars may be used to carry supplies of liquid gas for lighting small towns and summer resorts from central stations -the latter being supplied as often as necessary by fresh carloads. Lightships and isolated lighthouses may be stocked with the illuminant for six months or more. Railroads are likely to find employment for it on their cars, and automobiles will doubtless utilize it for their headlights. Campersout may carry a lighting plant along in a