The new chimney should be placed upon the holder in such a way that the upper part of the wick tube, D, is a few millimeters beneath the base of the convergent cone.  The height to be given the wick varies according to the lamp used.  It is regulated so as to obtain a steady and regular combustion.  In oil lamps it must project about 11/2 centimeters.  If two lamps of the same size be observed, one of which is fitted with the new chimney and the other with the old style, we shall be struck with the difference that exists in the color of the flame as well as in its intensity.  While in the case of the cylindrical glass the flame is red and dull, in that of the circuit it is white and very bright.  This, however, is not surprising when we reflect upon the theoretical conditions upon which the construction of the new chimney is based—­the strong influx of air having the result of causing a more active combustion of the liquid, and consequently of raising to white heat the particles of carbon disseminated through the flame.  As it was of interest to ascertain what the increase of illuminating power was in a given lamp provided with the new chimney, Mr. Felix le Blanc undertook some photometric experiments.  The trials were made with a Gagneau lamp provided with a chimney of the ordinary shape, and then with one of Mr. Bayle’s.  The measurements were made after each had been burned half an hour.  The light of the standard Carcel lamp being 1, there was obtained with the Gagneau lamp with the ordinary chimney 1.113 carcels, and with the Bayle chimney 1.404 carcels.  Thus 1.113:1.404 represents the ratio of the same lamp with the ordinary chimney and with that of Bayle.  Whence it follows that the light of the lamp with the old chimney being 1, that with the new one is 1.26, say an increase of about 25 per cent.  There is nothing absolute about this figure, however.  On kerosene lamps the new chimney, compared with the contracted Prussian one, gives an increase of 40 per cent. in illuminating power, and the oil is burned without odor or smoke.

As it was of interest to see whether this increase in intensity was not due to a greater consumption of oil, a determination was made of the quantity of the latter consumed per hour.  The Gagneau lamp, with the old chimney, burned 62.25 grammes per hour, and with the Bayle 63 grammes in the same length of time.

It may be concluded, then, that the increase in light is due to the special form given the chimney.  This new burner is applicable to gas lamps as well as to oil and petroleum ones.

The effects obtained by the new chimney may be summed up as follows:  increase in illuminating power, as a natural result of a better combustion; suppression of smoke; and a more active combustion, which dries the carbon of the wick and thus facilitates the ascent of the oil.  The velocity of the current of air likewise facilitates the action of capillarity by carrying the oil to the top of the wick.  Moreover,