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Modern Improvements in Oil Lamps - The Principle of the Bunsen Burner - A Comparative Table of Costs under Different Systems of Lighting - Gas Lighting - How to Combine Economy and
Hygiene - Petrol Gas
In no department of the household has modern science achieved such important improvements as in the means for lighting our rooms artificially. Indeed, during the last generation, domestic lighting has been completely revolutionised.
The old-time lamps, redolent of paraffin, and ever ready to fill the room with pungent smoke, have given place to "duplex" and "central draught" lamps, from which objectionable defects have been largely eliminated.
Yet further improvements in the lamp-burner, moreover, are available, and may be expected to replace those of the present style lamp as soon as they have become sufficiently well-known.
The naked yellow, flickering gas flame already has almost disappeared, in favour of the steady, white, and cleanly light of the incandescent mantle.
In connection with electric lighting, the modern development is the incandescent lamp, which, if not superior to its predecessor in quality of light, at least produces the same result at lower cost.
For the householder interested in the economical aspect of the subject these improvements mean a very substantial yearly gain.
Progress in the direction of improved means of lighting, however, has not been confined to what we may term "town systems." For dwellers in isolated country places, where gas and electricity companies are conspicuous by their non-existence, the enterprising inventor has evolved admirable systems of domestic lighting, of which acetylene and petrol gas are examples.
The improvement in oil lamps which followed the introduction of the circular wick, to which the air supply is conveyed both externally and internally (central draught), meant a longer wick surface, with larger flame area in the same space, and incidentally, and, equally important, a brisker combustion, and therefore a better light. But the central draught lamp burns liquid oil from a cotton wick.
Science has shown that if the oil can be vaporised before it reaches the flame, and in the process supplied with a more liberal supply of air, a more perfect form of combustion takes place, and economy results.
This has long been known as the principle of the "Bunsen burner." Only recently has it been applied to oil lamp burners, though for a generation it has been the basic principle of the incandescent gas burner.
Illustrated is a sectional view, showing the very simple construction of the Bunsen burner as applied to gas. The flame, though only faintly luminous, is intensely hot. This accounts ' for the high degree of luminosity of the gas mantle when heated by it. In applying the principle to oil lamps, the first essential was to burn the oil in a manner to permit of effecting the necessary admixture of air with the oil vapour. This has been done in various ingenious ways in the incandescent oil lamp, some of which are wickless and some depend upon an asbestos (fireproof) wick.
The result is a white light without smoke, smell, or flicker, in no respect inferior to the light of an incandescent gas burner. At the same time the oil consumption is reduced to at least one-half of that required for the ordinary duplex burner.
Moreover, the incandescent lamp burner will burn equally well with oil of low price, say, 6d. or 7d. a gallon.
Compared with the incandescent gas burner, the cost per hour for the same amount of light is appreciably less.
A further development of the oil lamp, worked on the "high-pressure" system, and using an inverted mantle, shows an even greater economy, a 100-candle power lamp costing only id. for 16 hours of light. This represents the lowest cost of any domestic illuminant yet available.
To those who are not deterred from using oil by the trouble attendant on filling and cleaning the lamps, the following table of cost per 1,000-candle power per hour of different systems of lighting should prove to be of interest :
A central-draught oil burner, by means of which a better light is obtained at less cost than in the old-fashioned oil lamp
A Welsbach oil burner with a mantle, which yields a white, steady and odourless light, equal to that of an incanaescent gas burner
High-pressure oil lamp (wickless)
Low-pressure oil lamp...........
Ordinary yellow flame "lamp (with wick) ..
Coal gas (incan-descent)......
Electricity, at 3 1/2d. per unit
It is claimed for the oil lamp that oil vapour is not so destructive of mantles as gas, and that the products of combustion are not so harmful to internal decorations, both of which are important points for consideration when the relative economy of the various systems of lighting is under review.
It may be mentioned, to allay the fears of the uninitiated, that modern oil lamps of good quality, whether central draught or mantle lamps, are in every respect safe, even with the commonest of oils.
It was the writer's privilege to be taken over the laboratory of Dr. Welsbach, in Vienna, to see his then budding invention of the incandescent mantle. In its experimental stage it produced a weird, greenish light. Since then the incandescent gas mantle has been improved beyond recognition, and is now the basis of all the improved systems of artificial lighting, electricity and acetylene excepted.
The ordinary gas burner burns the gas imperfectly, and to that fact owes its luminosity, for the sickly, yellow radiance that pleased' our grandfathers resulted from the mild incandescenoc of carbon particles heated by the other part of the burning gas. Here really was the germ of the mantle idea, if inventors had only seen it, for the unburnt portion of the gas provided these particles, and the flame may be said to have formed its own mantle, if the carbon particles can be imagined as constituting an impalpable mantle.