ators to which they are attached. One four hundred horse power engine ran seven months without stopping. The producers do even better. The Erie Railroad has two producers of 200 horse power each at Jersey City, one of which was in continuous operation for seven years. With the exception of the engineer in charge, the work around a gas producer power plant can be done by unskilled men. If a gas receiver is used, and all large plants have them, the engine is always ready to start. It can be brought into full service in half a minute to a minute, for the cylinder requires no warming up and no draining as a steam engine does. Even the producer can be put in operation in fifteen or twenty minutes instead of the hour or hour and a half needed to raise steam under a boiler. Finally the gas producer power the increases in capital stock made possible by them. Producer gas, then, is made with apparatus which consists of a generator, a vaporizer and a scrubber. The generator is a steel cylinder lined with firebrick, and having a revolving grate at the bottom. The bottom is closed by a water seal which permits cleaning and removal of ashes without interrupting the operation of the plant. At the top is an automatic charger, with double shutters, through which coal can be introduced without interfering with the working of the generator. To start up, the generator is filled with fuel and lighted and the blower turned on. Small plants have hand blowers, the larger ones have blowers operated by compressed air, which is stored while the plant is in operation. When the coal is TWIN TANDEM 3000-HORSEPOWER GAS ENGINE. plant is quiet and law-abiding. It is not The instrumentality through which such economic miracles are wrought possesses a lively interest for all. Radical reductions in the expense of power means a cheapening in the cost of production of manufactured articles. Of course the ordinary citizen does not directly profit by these economies, nor should he expect to do so; but he is freely welcome to the pleasure of reading about incandescent, the air valve at the bottom is closed and the valves are opened which permit the gas to flow into the vaporizer. This is a water-jacketed pipe or vessel in which water is maintained at a constant level. In passing through the vaporizer the gas gives up its heat and in doing so generates a little steam in the surrounding water, which, mixed with air is fed to the generator. The gas then flows into the scrubber where impurities are washed out in a cylinder of coke upon which water is sprayed, through a water seal and then over trays filled with sawdust, when it is ready to go into the engine cylinder or into the receiver to wait until wanted. The process is auto apparatus requires to be more elaborate than if anthracite or coke is used. In large plants the gas is stored in a receiver as it is made. In small plants a suction producer is used. In this case the suction of the engine draws off the gas just as it is required, thus doing away with the necessity for a receiver. The same operation which draws off the gas sucks sufficient air and steam into the generator to combine with the carbon and keep up the supply of gas. Only anthracite and coke can be used in the suction producer. Bituminous coal contains too much tar. Suction gas producers are particularly adapted to any work where small power is required, including automobiles and motor boats; but plants as large as 500 horse power weighed but 250 pounds. The space occupied was a negligible factor, as may be inferred by the fact that the appearance of the automobile was not materially changed. In a test run the producer consumed nineteen and one-eighth pounds of coke and two gallons of water per hour, making the cost six cents an hour as compared with forty cents for gasoline. A German manufacturer has turned out a portable gas producer and engine on wheels to take the place of the portable steam engine. The hopper carries coal enough to keep the generator going for forty-eight hours. Narrow gauge locomotives using producer gas are built by the same manufacturer. The gas engine itself has been radi cross cally improved. It is no longer the It is no longer the single acting single cylinder affair of its callow days. Ten years ago a Scotchman found out how to make double acting gas engines. Then others discovered that by driving two single acting cylinders tandem they could get as many impulses on a single crank as with a simple steam engine, and, with twin tandems, as many impulses as from a compound steam engine, and at the same. time have a motor that was just as steady running as the best regulated steam engine. This was all that was required to adapt the gas engine perfectly to driving electric generators or doing other work requiring smooth, steady running. Large engines are started by compressed air which is stored for the purpose while the engine is at work. No large vessels have yet been equipped with gas producers and engines; but it has been demonstrated on paper, at least, that such installation is entirely practicable.. Vertical gas engines of 3,000 to 5,000 horse power have been built. Reversing, which is essential in a marine engine, may be effected by the use of compressed air. It is estimated that the saving on the initial cost of a 10,000 horse power producer gas engine installation on shipboard would be in the neighborhood of $45,000, that the annual saving in operating expenses would be somewhere near $60,000, and that the additional space saved if occupied by cargo would pay ten per cent on the investment. While the producer gas engine is able to show a record of results so far superior to the best performances of the steam engine there is still abundant scope for the exercise of inventive talent. Of the heat generated in the gas engine cylinder only twenty-five per cent is utilized in work. Of the rest forty per cent goes into the water jacket and thirty-five per cent is lost in the exhaust and in radiation. There are many who feel sure that the next step in advance in power production will be the gas turbine. A number have been tried, but none have proved successful. The most recent was built in France. In a trial last September it contrived to turn into effective work eighteen per cent of the heat value of the fuel supplied to it. One of the great problems confronting the inventor who would produce a gas turbine is how to keep his machine from melting. The temperature in an internal combustion. engine sometimes reaches 2,000 degrees Centigrade, which is above the melting point of platinum, to say nothing of cast iron. The ordinary gas engine can be kept cool with a water jacket; but the swiftly revolving blades of a turbine are a different matter. The Frenchman referred to kept the temperature of his turbine blades down by introducing low pressure steam. From this it may be seen that the gas turbine has a long way to go to get out of the woods. Indeed, The-Man-Who-Knows-It-Isn't-So has demonstrated the utter impossibility of ever producing a practical gas turbine, just as conclusively as he proved that, steamboats wouldn't go, that the first transcontinental railroad could never be built, or that the automobile was impossible and dangerous and ought not to be allowed, any way. Edison says we know nothing now, but that five hundred years hence we may begin to suspect. Perhaps the final solution of the power problem may fall under suspicion in even less time. Fifty thousand pounds of this "worthless" plant are imported annually from Belgium into the United States. Make Money Growing Weeds By Edward B. Clark Hundreds of thousands of dollars are sent abroad every year to pay for the dried leaves, seeds and roots of various medicinal plants which grow in abundance in this country, but which are classed by American farmers as weeds and ruthlessly destroyed. This article points out the opportunity for the establishment of a profitable weed farm.-EDITOR. T HROUGH the centuries man has been consider ing the lilies of the field to the neglect of the weeds thereof. The lily bases its claim to consideration on its beauty and on the scriptural injunction, and both are potent. The weed has a beauty for those who see things aright, but the spoken word has not been for its consideration, but for its condemnation. The weed, however, is worthy, though man would banish it, if he could, to the waste places. Even the nature-lovers of the kind scientifically bent, refuse to speak of the weed as a plant; a weed it is and nothing else and with the word must go, seemingly for all time, the general impression of worthlessness. If it were not for some of the weeds, spring would be put back a month. The early green in many cases is the green of the weed and often the first flower of the year is the weed's offspring. The weeds spread tables for the birds in winter. The goldfinch and the crossbill feast on the seeds which the tall stems hold above the drifted snow, and while man may feel as he may, no bird will despise that which gives it dinner. Recently the Bureau of Plant Industry of the United States Department of Agriculture has been giving its attention to the weed. Today it is telling the farmer that that which he has been looking upon as a pest has its uses and that it may profit him to consider the weeds. It is not a matter of common knowledge that some of the weeds "infesting" the land will produce the crude drugs which GOLDEN SEAL. The Indians early discovered its medicinal properties. today, in large part, are obtained by importation from abroad. Alice Henkel, an assistant of the government's plant industry bureau, says that the roots, leaves and flower of several of the weed species regarded as plagues in the United States are gathered, prepared and cured in Europe, and not only form useful commodities there, but supply to a considerable extent the demands of foreign lands. There are weeds in this country against which extermination laws have been passed which hold in their leaves, stems or roots medicinal properties which have a value in the work of preserv ing the health of the nation. It is possible in ridding land of weeds in order that crops may be grown, to make of the uprooted "pests" a source of income. Moreover it is possible to maintain upon land given over as worthless for crop growing purposes, a weed plantation, which after the harvest, will prove itself to be not less profitable than some of the tilled fields. Lobelia (Lobelia inflata) is a poisonous weed which grows abundantly in nearly every section of the country. It has all sorts of local names, being known in different parts of the land as Indian tobacco, wild tobacco, bladder pod, asthma weed, gagroot, vomitwort, low belia and eyebright. The lobelia sprang into fame-perhaps notoriety were the better word-years upon years ago. Samuel Thompson, a New Hampshire physician, experimented with the lobelia weed and, it was charged, used it so extensively in his practice that he succeeded in killing several of his patients, the poison of the weed doing the deadly work. It was said that Thompson by the use of lobelia "sweated two children to death." He was accused also of killing a Captain Trickey and a young man named Lovell with over-doses of the weed. The doctor was arrested and tried for murder, but finally was acquitted. His life was one constant warfare with the regular practitioners, and his use of lobelia was the cause of it. The regulars said that Thompson's theory and practice of medicine was, "I purge 'em, I sweat 'em, and whether they want to die or not, I let 'em." The leafy stem of the lobelia grows occasionally to a height of three feet from a fibrous root. The whole plant contains an acrid milky juice. an acrid milky juice. It flowers from July until the frost comes, the blossoms being pale blue and minute. The leaves and the flowering tops are used in medicine, for notwithstanding their drastic properties, they are of salutary service in skilled hands. The seeds also are in good |