The cost of the incandescent light is therefore about one-half that of the regenerative, and only one-eighth that of the plain burners.

The following is taken from the report of Professor Carlton Lambert, M.A., F.R.A.S., dated July 27, 1894: - "The Welsbach light is nearly seven times as efficient in illuminating effect as ordinary gas-burners, more than four times as efficient as an "argand", and more than twice as efficient as a regenerative lamp. From theoretical considerations, it is evident that the quantity of carbonic acid actually produced by each foot of gas burned must be the same with the "Welsbach" as with the "Bray", or any other burner with which the consumption is perfect The vitiation of the air by the "Welsbach" light is almost negligible, being between one -fifth and one-sixth part of that produced by ordinary burner giving the same amount of illumination. The heat evoled by "Welsbach" burners is a little less than one-seventh part of that emitted by ordinary gas-burners giving the same illumination." I have italicized portions of this quotation, lest they should be overlooked. The illuminating power of the "Welsbach" burners is excessive, and, in house-lighting, a large proportion is wasted. one "Welsbach giving 60 candle-powers should be sufficient for a medium-sized room requiring four No. 5 Bray burners. In practice it will be found that, owing to the intensity of the light, heavily-muffled and tinted globes and shades must be used, necessitating the fixing of (perhaps) three "Welabaeh" burners instead of one. For this reason the comparisons in the last two sentences of the report are somewhat misleading.

The special "Lancet" Commission reported in January, 1895, much more clearly, the four most important "conclusions" being as follows: -

" 1. The burner (with or without the mantle) is not prejudicial to health.

"2. The heat and carbonic acid produced by the combustion is [sic] one-half those of an ordinary gas-burner, though the light given is more than three times as great.

" 3. The heat and carbonic acid produced is [sic] less even than those of the average oil-lamp. . . .

" 5. There is not a trace of any poisonous gases - such as carbon-monoxide or acetylene - in the products of combustion."

It is clear from these reports that the incandescent system of gas-lighting is to be highly recommended on account of its illuminating power, small consumption of gas, and consequent slight vitiation of the atmosphere.

There are five descriptions of Welsbach incandescent burners issued for domestic lighting: -

1.

The

"C"

burner.

2

"

"

with

governor.

3.

"

"

"

by-pass.

4.

"

"

"

governor and by-pass.

5.

"

"S"

"

"

by-pass.

The construction of the burner, and the method of taking it to pieces for cleaning or regulating, and also for the refitting of mantles, will be understood from figs. 654, 655, 656, and 657.

The "C" burner, complete with mantle and chimney, is shown in Fig. 654, about one-half the real size, and the several parts are shown in Fig. 655. This

Fig. 654. Welsbach Incandescent C Burner.

Fig. 654.-Welsbach Incandescent "C" Burner.

Fig. 655.   Parts of the Wesbach Incandescent C Burner.

Fig. 655. - Parts of the Wesbach Incandescent "C" Burner.

Table XXXIX A Comparison Of Incandescent Gas Burne 500105

Fig. 656.

Broach for the Boner burner is regulated to consume 3 cubic feet of gas per hour, at a pressure of one inch. If, however, for local requirements, it is necessary to regulate the burner to suit a higher or lower pressure, instructions to that effect should be given when ordering. The regulating of the burner may, however, be done by means of the "broach", illustrated in Fig. 656. If the holes in the nipple Fig. 655, are too large, they can be burnished down by the round end of the broach, until the holes are sufficiently small to pass just the amount of gas required. Should the holes be too small, then the needle in the same broach is used to increase their size. Only a very slight enlargement of the holes is necessary to make them of the required size. In Fig. 655 a is the gallery, on the top of which is a small hole a, into which fits the central mantle-rod g. It also supports the chimney; and the globe-ring E, which carries the globe, slips over and rests on the outside of the gallery. The part B is the bunsen tube, and the nipple, which, when screwed together, form the complete bunsen burner. D shows a plate which slips over the bunsen as far as the shoulder, and prevents the lighting back so frequent in all bunsen burners, f is a brass nose-bit or "adapter" with male threads, the larger end made to screw into the bottom of the nipple under the burner, and the tapered end to screw into the burner-socket on the gas-fitting.

The "C" burner with governor is in all respects the same as the ordinary "C" burner, with the addition of a small governor underneath, and, in consequence of this, the air-holes of the bunsen burner have to be made somewhat larger. This "C" burner with governor is recommended in all instances where the pressure of gas varies greatly. There is no doubt that the duration of the mantle and chimney is greatly shortened by extreme variation in the pressure of the gas, and a great saving will be effected if a governor is used, as it keeps the bunsen flame always steady, the consumption of gas is always the same, and the breaking of the mantles and chimneys is greatly reduced. The governor is so adjusted that the necessary amount of gas to bring the mantle to full incandescence is obtained with 6/10 ths pressure, and however the pressure may increase, the burner will not consume more than 3 cubic feet of gas per hour.