Mention is made below of the principal points to be attended to in order to get good results with the "Welsbach burner. The burners ordinarily supplied are intended for use with gas of from fifteen to twenty candle-power, and it is an advantage to know whether the gas comes within this range, since it is generally necessary to use slightly larger nipples for a poorer gas and smaller nipples for a richer gas. It is also necessary to know the average pressure during lighting hours, and to select the nipple most suitable for that particular pressure; if, for instance, the pressure varies from 1 in. to 2 1/2 in. during lighting hours, select a nipple most suitable for l 1/2 -in. pressure. Having decided on the most suitable nipple, take care that it is screwed into the socket gas-tight, as the least leakage will cause a bad Bunsen flame; the nipple itself should be examined to see that its interior is quite free from dust, grit, or other foreign substance, and on lighting the gas on the nipple (without the Bunsen tube) the flame ought to be perfectly vertical.

See that the wheel on the top of the Bunsen is exactlv centred, and lies evenly, perfectly flush with the top of the burner, otherwise the Bunsen flame will be one-sided ami cause the mantle to shrink more on one side than the other; the result being that the mantle will be out of shape after burning a lew hours. See that all burners are fitted perfectly upright and that the right-sized rod is used with every burner. The rods should be 6.1 into the burner pretty tightly; it they lit loosely they may be packed with a Little asbestos, Also note that the Bunsen flame of the Kern burner is quite different from the ordinary "C" burner. The ring just above the wheel should be of a whitish-blue colour, not green. The mantle ought to be fully incandescent from top to bottom, and no flame should be visible outside or above the mantle. Should the Bunsen flame of the new burner resemble that of the "0" burner it would indicate that the nipple on the burner is too large, or that the flame when lighted on the nipple (without the Bunsen tube) is not vertical.

This should be remedied, as it means a loss of forty per cent, of light.