The advent of gas, and, at a later period, electric current, for illuminating purposes has, to an extent, restricted the use of oil as an illuminant, yet the reader will be surprised to learn that at least 2,000,000 oil lamps are nightly lighted throughout Great Britain. The inhabitants of the majority of our villages have to fall back upon oil lamps after nightfall, and even in remote spots where enterprising gas companies have laid gas mains large numbers still keep faith with oil, no doubt by reason of its cheapness in normal times. The greatest improvement made in regard to oil lighting has been in connection with the introduction of the incandescent mantle. As a result of this innovation, several elaborate designs of lamps have been placed on the market, and to-day oil is frequently used in large residences in preference to the more modern illuminants. This is due, without doubt, to the fact that oil light is particularly soft, and, while giving a great illuminating power when consumed under the best conditions, lacks that dazzling brilliancy which causes injury to the eyes. One of the earliest methods of utilizing petroleum under an incandescent mantle was the Kitson system, according to which illuminating oil is compressed to about 50 lb. per square inch in a suitable vessel, forced through a soft brass tube of very small bore into a heating chamber, and, subsequently, through a needle orifice to a Bunsen burner. The Kitson system, which has found many adherents in the United Kingdom and abroad, is particularly adapted for lighthouse illumination, and in such cases where large units are essential. It is interesting to record the fact that for some time one of London’s main West-end thoroughfares was illuminated by incandescent oil lamps, and, though they are now superseded, no tangible reason was given as to why these highly economical means of illumination were ever removed. Space forbids my referring to the various designs of oil lamps on the English market to-day: they may be counted by their hundreds, while still a larger number of those which have either been unsuccessful or have found no sale may be found in the records of the Patent Office. During comparatively recent times, devices have been brought forward whereby remarkably good results have been achieved by the use of gaseous vapour for portable lamps. In these cases, motor spirit is vapourized and used under an incandescent mantle. The best known of these lamps is the “Petrolite.” In this lamp, a porous stone is impregnated with suitable hydrocarbons--motor spirit--and a current of air is introduced, the necessary draught being provided by the use of a fairly long chimney. The great advantage of the “Petrolite” lamp is that of its perfect safety, for if by any chance the lamp becomes overturned and the chimney displaced or broken, the draught ceases, and with it, the generation of the inflammable vapour; the lamp, therefore, immediately going out.