About the middle of the last century, when the petroleum industry was making steady advance in several European countries, and a little later, when the United States entered upon its era of oil progress, there was marked development in the use of oil for lighting purposes. The more modern oil lamp was introduced, and it is worthy of record that in one year alone over fifty patents were taken out in the United States for oil lamp improvements. The Germans, too, were not behind in this respect; in fact, it is very largely due to the numerous German improvements that the general governing principles of present-day oil lamps became so popular. There is no doubt that the ordinary oil lamp has often been, and still is, unjustifiably condemned for certain defects which are not inherent in it. It necessarily demands attention if it is to give a satisfactory light, but, unfortunately, this attention is not adequately bestowed upon it, and complaints are the result. I have frequently argued that, just as it is possible with inattention to make the most improved pattern of oil lamp operate unsatisfactorily, so is it possible, with a little care and common sense, to get a really good and satisfactory light from the cheapest oil lamp obtainable. In days gone by, the quality of the oil was, in many cases, unsuitable for burning in the ordinary lamps; its lighting power was very inferior, and it gave off a distinctly unpleasant smell. To-day, however, the illuminating oil sold throughout the world is a first-class article, and its flash-point has been so raised that it can be used freely without there being any suggestion of its lack of safety. One still hears of the “dangerous” paraffin lamp, but, to all intents and purposes, whatever danger was attendant upon the use of oil lamps has long ago departed, though, of course, care must always be exercised, a remark which naturally applies to every illuminant. It is not within my province to give a series of hints to the ordinary user of illuminating oil, but it is well to draw attention to a point which is frequently overlooked: that is, to see that lamps should be kept well filled. It has been established that the light from an oil lamp is greatly affected by the quantity of oil in the reservoir. An increase of 20 per cent. can be secured in the illuminating power of the lamp if only the oil is kept to a good level in the container. This is due to the assistance given to the capillary action of the wick by the higher level.