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only to the reader but to Octavia. Some persons require close reading between the lines to discover this fact, and to any one who overlooks the following passage-at-arms it must have somewhat the aspect of a mental reservation of the author's:
"Is Lady Theobald very fond of you?" Octavia had asked, in the course of this visit.
"It is very kind of her if she is," he replied, with languid irony.
"Isn't she fond enough of you to do anything you ask her?" Octavia inquired.
"Really, I think not," he replied. "Imagine the degree of affection it requires! I am not fond enough of any one to do anything they ask me." Octavia bestowed a long look upon him. "Well," she remarked, after a pause, "I believe you are not. I should think so."
Barold colored very faintly.
"I say," he said, "is that an imputation, or something of that character? It sounds like it, you know."
Octavia did not reply directly. She laughed a little.
THE WORLD'S WORK.
Improved Iron Punch
EVERY kind of structure, bridge, ship, house, and car, and all our power, is, more or less, dependent upon the strength or want of strength in riveted iron-work. No subject has received so much attention within the past few years as the methods used in joining pieces of iron by rivets, and the making of the holes for the rivets has already given rise to a great literature. If the riveted work be weak, wherein is our faith in bridge, or ship, or boiler? Even so small a tool as a rivet-punch deserves careful attention. A new punch for making rivet-holes by a smashing blow has the addition of a cutting lip or edge just above the point. This same smashing blow makes the weakest kind of rivet-work, because the edge of the hole is ragged, torn, and cracked, and the rivet makes an ill-fit, a bad joint on which to hang human lives. The addition of a curved lip on the punch acts as a shearing or paring tool, shaving off the ragged edges of the hole and leaving it smooth and evenly fitted to the shape of the rivet. Riveted work made in holes punched by the new tool appears to stand a higher test than will the same class of work made with ordinary punched holes, or punched and reamed out holes, or drilled holes. The rivets were sheared off in a Riehlé testing machine at a strain of 38,820 pounds for the punched plates, 39,210 for the drilled plates, and 39,850 pounds for the plates punched by the new tool.
Barold's snobbishness to Octavia is more a matter of tone than of words, and Mrs. Burnett has, accordingly, treated it subtly; but, in view of Bar. old's respectful conduct toward her in the early part of the book, a little more emphasis might have been given to the above incident. No doubt many would have welcomed a relenting touch of generosity in Octavia at the last, but we are inclined to think Mrs. Burnett has been truer to the demands of the situation in rejecting this sentimental touch. Indeed, she might have omitted “Jack” entirely, and cleared Octavia of the imputation of disloyalty, but this would have involved a more refined type than the author set out to describe, and would have weakened the force of the climax. Mr. Barold him. self would be surprised to learn that Mrs. Belasys turned out to be—but this must be left to Mrs. Burnett, who, if she chooses to follow her farther, will doubtless be accompanied by as large and eager an audience as that which has enjoyed this fine piece of literary comedy.
Gas for Kindling.
THE idea of combining gas with coke or anthracite coal in a grate fire seems to have proved of some practical value, and the new style of grate used with these combined fuels may be briefly described
as offering a valuable suggestion in domestic economy and in burning coal in all kinds of furnaces. No intimation appears to be given that any patent is to be taken out on the new application of gas fuel, and the apparatus is so simple that it can be made by any skillful worker in sheet metal. The theory is to apply a continuous gas flame to a mass of coke or hard coal, burning in a common open grate. To accomplish this, the horizontal bars of the grate are removed, and at the back of the fire-place, next to the wall, is placed an upright plate of copper reaching from the bottom of the ash-pit to a level with the top bar of the grate. To this is riveted a flat plate of cast-iron placed horizontally on a level with the bottom of the grate, or in place of the bars that were removed. This gives a fire-box with a solid iron bottom and an upright back of copper, the front bars remaining in place. The horizontal plate does not reach quite to the front, and there is a narrow opening between the plate and the lowest bar of the grate. Under the iron plate is a second one, also of iron, bent at a right angle and having a hinged trap-door at one edge, the trap being kept in place by a spring.
The accompanying drawing is a section of such a grate. The upright copper plate is marked A, the | horizontal iron plate is marked C, and the angle plate and trap-door are marked D and E. Attached to the plate A is a strip of sheet copper bent into a series of corrugations and marked B in the drawing. At F is a gas-pipe, 13 mm. (1⁄2 inch) in diameter, extending the whole width of the grate just behind the lower grate-bar. This is perforated with small holes along the upper side, thus forming a series of small gas-burners. The grate is filled with coke or anthracite, and the gas is turned on under the solid fuel and set fire. No kindling is required, and the
tion (except what may enter between the bars) is intended to pass between the corrugations and between the two iron plates, as shown by the arrows in the drawing, and thus meet the gas flames at a high temperature. This makes a regenerative furnace of the grate, the gas flames burning with more heat and flame when fed by the heated air. Such a regenerative grate, burning gas and coke, is said to give more heat than can be obtained from the same amount of coke burned in the common way, or more than the gas and coke together in an ordinary grate. This is explained partly by the fact that the fire is kept at all times at the front of the grate, as the plates prevent it from burning very freely at the back, and thus the heat is thrown out into the room. The heating of the air needed for combustion also materially helps by producing a large and hot flame. Economy of fuel is obtained because the fire is at the front of the grate only, and as the coke wastes and falls below, new fuel, already highly heated, moves forward, and only a portion of the solid fuel is burned at a time, instead of being consumed in one wasteful mass, as in the common grate. In grates where it is not convenient to remove the horizontal bars, the gas-pipe may be simply laid behind the lower grate-bar, and the rest of the grate may be covered with a thick plate of cast-iron, laid on the flat bars. In this case the regenerative apparatus would be left out, and the combined fuels would be burned with less economy. This form of regenerative grate, and this combination of solid and gaseous fuels, certainly possess the advantage of cleanliness and ease of starting and management. No kindling is required, and as fast as the coke is burned more may be added, and the fire kept up continuously. There is also the advantage of saving the unburned fuel, for when the gas is cut off the coke goes out very quickly; it may be started again, without waste, by simply lighting the gas.
Aside from the advantages of such a combined gas and coke fire, the idea readily suggests another that does not appear to have been considered by the inventor. In burning anthracite, the difficulty is to make it light quickly and thoroughly, even a small fire involving the trouble and expense of a wood fire. If open grates, designed for hard coal, were supplied with a perforated gas-pipe, placed behind the lower grate-bar, and this was connected with the mains, gas could be used in kindling the fire. Such a gaskindling apparatus should have an opening in the pipe for mingling air with the gas before it is burned, thus making a Bunsen burner. Such a burner would give more flame and heat for the same amount of gas, and it would take the place of the paper and wood used in kindling the coal. After the coal is fired, the gas could be cut off, and the perforated pipe would deliver air instead of gas, and thus assist the combustion.
Another and more simple plan, that may be applied to stoves, ranges, and the furnaces of steam-boilers, would be to make a nest, or gridiron, of perforated gas-pipe, about the size of the grate, or even smaller, and arranged as a Bunsen burner. The grate, or fire-box, might then be filled with fuel (without kindlings), and the gas-burner placed in the ash-pit, close up to the grate-bars. In this position the gas flames would rise through the grate-bars and quickly fire the coal. While this suggestion is made here, it is believed, for the first time, it may be remarked that the idea is not new, as on several railway lines the fires under locomotive boilers are now kindled with gas. A bar of wood or iron is inserted between two of the bars, near the middle of the locomotive fire-box, and over this is piled a quantity of large coal. The rest of the fire-box is then filled evenly with fuel, and then the bar is drawn out. In the arched opening thus left under the coal, is thrust a gas-pipe, supporting a series of Bunsen burners. Connection is made by hose with the street-mains, and the burners are lighted from the fire-door of the boiler; the gas flame rises through the coal and quickly sets it all on fire, when the burners are withdrawn and the boiler is ready for firing in the usual way. Ten feet of gas is found sufficient to start the fire in about twenty minutes. If gas can be used with economy in lighting large fires in boilers, and of this there seems to be no doubt,-the small burners suggested for domestic use would certainly effect a great saving in time, labor, kindlings, ashes, and dust, and probably expense, in starting the kitchen or parlor fire.
The Transformation of Light into Sound. THE remarkable discoveries announced by Professor Bell, at the time of the invention of the photophone, in relation to the action of an intermittent beam of light upon various substances upon which it was thrown, have been recently made the subject of exhaustive research by Professor Tyndall, of London. While the experiments of Professor Tyndall do not point immediately to anything of practical value in the general work of the world, they are
worthy of consideration, because any new facts or laws that employ common tools and methods may, in other hands, result in useful inventions. The photophone showed that an intermittent beam of light could be made to reproduce its vibrations as sounds that could be heard in a telephone. In the new experiments, the sound is made directly audible without the aid of the selenium receiver of the photophone. A beam of light from a lime-light, or even a candle, has its rays rendered parallel by a reflector, and is directed upon a small glass flask. To the neck of the flask is fastened a rubber tube, having at the end an ear-piece. Between the flask and the source of light is set up, vertically, a disk of sheet metal, having radial slots cut in it near the edge, or having the edge cut into deep notches, or serrations. This is made to revolve swiftly on its axis in the beam of light, alternately allowing the light to pass through the slots, or between the serrations. By this arrangement the beam of light may be made intermittent, or broken up into a succession of alternate flashes of light and shadow. The flask is then filled with various vapors, or gases, and the beam of light, falling on these, imprints its vibrations of heat and cold (not light, but obscure heat, for all the light may be cut off, and the effect is the same), and the vapor, or gas, expands and contracts in exact unison with the vibrations. If these vibrations are sufficiently rapid, they may set up in the flask a musical tone that may be distinctly heard through the rubber tube. Different vapors and gases give different results, some giving out powerful notes that may be heard without the aid of the tube. For the purposes of experiment, carbonic acid and olefiant gas have been found best. These experiments open a wide field for research that may yet lead to useful results. No intimation has been given that a patent will be placed on these photophonic discoveries, and any one is at liberty to follow the experiments so happily begun on two continents.
A PREPARATION of sulphide of lime, under the name of luminous paint, was first made on a commercial scale in England two or three years since, and has been recently introduced into this country. The method of making the sulphide of lime and its peculiar properties have been known for a long time, and the recent development of the art and the greatly increased value of the material are simply the results of improved manipulation. From a careful inspection of the new paint, it appears to possess qualities that make it highly useful when applied to surfaces that may be exposed to sudden changes from light to darkness. In appearance, the new paint is thick and creamy, and quite coarse in texture. It is best applied with a broad, thin knife, or spatula, as it is too pasty to work well under the brush. The paint in the pot, and when applied to any surface and thoroughly dried, is of a pale yellowish white, while the surface is granular and rather rough. A large sheet of paper, stretched on a frame and painted, was placed before a north window for about two
minutes on a cloudy day, and was then carried into a small room that was quite dark. In the dark room the paint exhibited a rich purple color, that seemed to glow and burn very much as will sulphur from a match when gently rubbed on the hand in the dark. The purple light that came from all parts of the painted surface was reflected on the walls and on the faces of the persons in the room, and plainly lighted up the room so that any ordinary work could be performed without difficulty. The light was not bright enough to read by, yet quite sufficient to enable persons to be seen and recognized. The purple light slowly faded away and turned to white, this white light remaining visible for six hours. The hand, laid on the paint for a moment, left an exact reproduction in deeper purple, showing that heat intensified the effect. This glowing figure of the hand soon faded as the heat was dis. persed. A lump of ice touched to the paint, on the contrary, makes a black spot, and seems to completely quench the light. Such a light-absorbing material naturally suggested a number of useful applications, many of which have proved to be of practical value. A sheet of gelatine coated with the paint may be taken into a dark closet, bank-vault, powder-room, or cellar, in place of a lantern. The light given out by the paint is sufficient to enable one to examine a gas-meter, find papers in the boxes of a safety-deposit bank, or to store or handle inflammable or dangerous substances. For searching for leaks in gas-pipes, the paint would be of the greatest value, as there would be no possibility of danger from explosion. The paint has been applied to clock-faces, to signs, to the interiors of cars that pass through dark tunnels, to powder-rooms, and to tools and materials that are occasionally used in dark places, and it has proved itself of practical value. From the material examined, it would appear that the luminous paint will be useful wherever a moderate degree of light is needed for a few hours, and wherever a burning lamp of any kind would be inconvenient or dangerous. The formula for making this sulphide of lime was described in this department, Vol. XX., page 478, but the improved processes whereby the luminous quality of the paint has been so much increased are known only to the manufacturers.
Improved Window Shade.
THE ordinary outside awning for windows has its disadvantages: while shutting out the sun, it also impedes the air and lets in all the dust, smells, and noise from the street below. It is supported by a bar of iron pivoted to the sides of the window just below the middle of the sash. Some ingenious inventor went farther and placed the ends in a slide so that it might be pulled up close under the window cap in wet weather. A more recent, and certainly more happy thought, is to provide two bars hinged together and to provide more canvas, and a different system of hanging. By this modification, the Italian awning becomes an American convenience. The new awning may be open at the top and closed at the bottom, to shut out the dust