OIL LAMPS have the advantage of convenience in, some instances, being everywhere ob-. tainable ; but if used, considerable care should he bestowed upon them. The thisagreeable odour issuing from them, when improperly attended to, is unpleasant enough in itself ; but there is a still greater danger of these fumes causing deterioration of the paper. This is, per haps, of no importance to the small' worker, but it is considerably so where a quantity of paper is kept. See, therefore, that the lamp is well cleansed, a good practice being to soak the burner occa sionally in hot soap and water. No charred pieces of wick should be allowed to find their way over the draught holes. These remarks apply equally to other cases where oil lamps are used. It is essential that the light should be kept as constant as possible, and to ensure this the wick must receive proper attention. It is preferable to rub away the charred portions of wick with a piece of paper, rather than to cut them with a pair of scis sors, as the latter generally results in an uneven edge, with consequent loss of light.
It is, perhaps, hardly necessary to point out that the quality of the oil materially affects the nature of the light. The latter is con siderably more actinic, besides being visually more brilliant, when it is pro duced by the better class of oil. More over, the combustion products are greater in the case of the cheaper kind. Some workers recommend the addition of a little camphor to the oil, as giving a white light, which it certainly seems to do. One decided disadvantage of this illumin ant is the amount of heat given out ; which, when the negative has to be placed to it, is liable to crack the latter. en a reflector is used behind an oil tip, it should not be of such curva cases where " dodging " has to be done on the back.