In the mean time, however, while electricity for lighting purposes has, to say the least, not made any startling advances, we have, besides the regenerative lamps before mentioned, the new Welsbach light, which is exhibited before you to-day, by the kindness of Dr. Wallace; and if the results said to be obtained by it are at all what they are represented to be, we certainly have a new departure in gas lighting of no mean order. Dr. Wallace--a gentleman who is well known to us as one well qualified to test its merits--has found that the Welsbach burner produces a light equal to more than 9 candles per cubic foot of gas of 25 candle power, thus nearly doubling the amount of light compared with gas consumed in the ordinary way.
The construction and manufacture of the burner I have seen described in these terms: Chemists have been diligently working for many years on the problem of how to convert into light the highly condensed heat of the Bunsen burner; and a Vienna chemist now claims to have solved it.
The first condition of the problem was to find a medium on which the heat could be perfectly concentrated and raised to illuminating power. Many experiments have been made with platinum in a Bunsen flame, and a brilliant enough light has been produced, but at a cost altogether outside commercial use. The Vienna chemist, Dr. Welsbach, has discovered a composition which is as good a non-conductor--that is to say concentrator--of heat as platinum, is much more durable, and a great deal cheaper. The base of it is a peculiar clay, found in Ceylon, which combines the indestructibility of asbestos with the non-conducting property of platinum; and having found the incandescent medium, he has next adapted it to the Bunsen burner.
In this arrangement there is the simplicity of genius. He gets a fine cotton fabric woven into the shape of a cylinder, with a tapering point. In its first stage it is about 2 inches in diameter; and after being coated with the composition, it is subjected to a strong heat. This has two effects--first, the cotton fiber is completely burned out, while the composition retains the shape of the woven surface on which it was moulded. Then the cylinder contracts and solidifies until it becomes about the size of the forefinger of a glove. Dr. Welsbach calls this his "mantle;" and by a simple arrangement he fits it on a Bunsen burner, and places an ordinary lamp chimney over it. When the flame is applied, the "mantle" becomes incandescent, and gives out a brilliant yellow light, which, it may be said without exaggeration, will compare favorably with any electric light yet put on the market.
For decorative effect a pretty frosted globe is used; and by varying the globe a pure white or a pure yellow may be obtained. It is also added that there is no act of Parliament required for it, nor even a provisional order of the Board of Trade. No streets have to be broken up in order to lay down pipes; and no wires have to be hung across the roofs of protesting householders.
The whole apparatus can be got ready to fit on an ordinary gas bracket; and two or three spare frames with "mantles" can be kept in the house in case of accident. Whoever sees the Welsbach incandescent light in operation will readily admit that it is the "coming light." It has beauty, brilliancy, purity, and economy all on its side.
Let us hope (added the chairman) this description is not overdrawn; but of this you will later on have an opportunity of judging for yourselves. No doubt the general or even partial adoption of this light would have a tendency to reduce the consumption of gas, as a smaller quantity would be required to produce the same amount of illumination. Nevertheless, gas engineers will hail it with approval if it in any way tends to popularize the use of gas, and helps to increase the comfort and improve the sanitation of our houses, churches, halls, etc. Moreover, gas is continually being adopted for fresh purposes; and we can confidently look forward to an almost unlimited field in the rapid and ever increasing use of gas as a fuel and for cooking purposes, as well as for motive power. The new and really excellent gas engines now being brought into the market will, no doubt, create a healthy rivalry, and tend to cheapen these useful machines, and so bring them within the reach of many persons who have hitherto been prevented from employing them by their considerable first cost.