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قراءة كتاب Scientific American Supplement, No. 481, March 21, 1885

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Scientific American Supplement, No. 481, March 21, 1885

Scientific American Supplement, No. 481, March 21, 1885

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دار النشر: Project Gutenberg
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adopting for main street or open space lighting in important positions; but when we consider that, with the fifty-four hours' system in workshops, artificial light is only wanted, on an average, for four hundred hours per annum, we may take it as certain that, at the present prices of regenerator burners, they are a bad investment for use in ordinary work. We must not forget that the distance of the burner from the work is a vital point of the cost question; and, for all except large spaces, requiring general illumination, a common cheap burner on a swivel joint has yet to meet with a competitor. Do not think I am old-fashioned or prejudiced in this matter. It is purely a question of figures; and my condemnation of regenerator burners applies only to the general requirements in ordinary engineering and other work shops where each man wants a light on one spot only.

Some people think that clear glass does not stop any light. This is a great mistake, as you will find it quite easy to throw a distinct shadow of a sheet of perfect glass on a white paper, as I will show you. Opal and ground glass throw a very strong shadow, and practically waste half the light. It is better to have a white enameled or whitewashed sheet-iron reflecting hood, which will protect the sides from wind, if such an arrangement suits other requirements.

I have endeavored in the engraving below to reproduce the shadows thrown by different samples of glass. This gives a fair idea of the actual loss of light involved by glass shades.

When lights are suspended, it is a common and costly fashion to put them high up. When we consider that light decreases as the square of the distance, it will be readily understood that to light, for instance, the floor of a moulding shop, a burner 6 feet from the floor will do as much work as four burners, the same size, placed 12 feet from the floor. It is therefore a most important matter that all lights should be as low as possible, consistent with the necessities of the shop, as not only is the expense enormously increased by lofty lights, but the air becomes more vitiated and unpleasant, interfering with the men's power of working. Any lights suspended, and, in fact, all workshop lights, must have a ball-joint or universal swivel at the point where they branch from the main, as they are liable to be knocked in all directions, and must, therefore, be free to move to prevent accidents. It is better to have wind-screens, if necessary, rather than glass lanterns, as not only does the glass stop a considerable amount of light when clean, but it is in practice constantly dirty in almost every workshop or yard.

 PILLAR LIGHT OR PENDANT FOR WORKSHOPS.

PILLAR LIGHT OR PENDANT FOR WORKSHOPS.

For bench work and machine tools, each man must have his own light under his own control; and in this matter a little attention will make a considerable saving. The burners should be union jets—i. e., burners with two holes at an angle to each other—not slit or batswing, as the latter are extremely liable to partial stoppage with dust. Where batswing burners are used, I have often seen fully 90 per cent. more or less choked and unsatisfactory; whereas a union jet does not give any trouble. It is not generally known that any burner used at ordinary pressures of gas gives a much better light when it is turned over with the flat of the flame horizontal, until the flame becomes saucer-shaped, as I show you. You can see for yourselves the increase in light; and in addition to this the workman has the great advantage of a shadowless flame. In practice, a burner consuming 5 cubic feet of gas per hour with a horizontal flame is a better fitter's than an upright burner with 6 cubic feet per hour. I do not believe in the policy of giving a man a poor light to work by—it does not pay; and I never expect to get a man to work properly with smaller burners than these. We have a good governor on the main: and the lights are all worked with a low pressure of gas, to get the best possible duty. As a good practical light for a man at bench moulding, the one I have here may be taken as a fair sample. It is free to move, and the light is as near the perfect position as the necessities of the work will permit. When the light is not wanted, by simply pushing it away it turns itself down; the swivel being, in fact, a combined swivel and tap.

 LOSS OF LIGHT BY GLASS SHADES.

LOSS OF LIGHT BY GLASS SHADES.

You will see on one of the lights I have here, a new swivel joint, which has been patented only within the last few days. The peculiarity of this swivel is that the body is made of two hemispheres revolving on each other in a ground joint. It will be made also with a universal movement; and its special advantage, either for gas, water, or steam, is that there is no obstruction whatever to a free passage—in fact, the way through the swivel body is larger than the way through the pipes with which it is connected. It can easily be made to stand any pressure, and if damaged by grit or dirt it can be reground with ease as often as necessary without deterioration, whereas an ordinary swivel, if damaged by grit, has to be thrown away as useless.

For meals, where a steam-kettle is not used, it is the best policy to have a cistern holding about 1½ pints for each man, and to boil this with a gas-burner. The lighting of the burner at a specified time may be deputed to a boy. If the men's dinners have to be heated, it is easy to purchase ovens which will do all the work required by gas at a much cheaper rate than by coal, if we consider the labor and attention necessary with any coal fire. Not that gas is cheaper than coal; but say we have 100 dinners to warm. This can be done in a gas-oven in about 20 minutes, at a cost for gas of less than 1d.; in fact, for one-fourth the cost of labor only in attending to a coal fire, without considering the cost of wood or coals. Gas, in many instances, is an apparently expensive fuel; but when the incidental saving in other matters is taken into consideration, I have found it exceedingly profitable for all except large or continuous work, and in many cases for this also. I only need instance wire card-making and the brazing shops of wire cable makers to show that a large and free use of gas is compatible with the strictest economy and profitable working.

Of all the tools in a workshop, nothing saves more time and worry than two or three sizes of good blowpipes and an efficient blower. I have seen in one day more work spoilt, and time lost, for want of these than would have paid for the apparatus twice over; and in almost every shop emergencies are constantly happening in which a good blowpipe will render most efficient service. Small brazing work can often be done in less time than would be consumed in going to the smith's hearth and back again, independently of the policy of keeping a man in his own place, and to his own work. The shrinking on of collars, forging, hardening, and tempering of tools, melting lead or resin out of pipes which have been bent, and endless other odd matters, are constantly turning up; and on these, in the absence of a blowpipe, I have often seen men spend hours instead of minutes. Things which need a blowpipe are usually most awkward to do without one; and men will go fiddling about and tumbling over each other without seeing really what they intend to do. They are content, as it all counts in the day's work; that it comes off the profits is

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