In fact, no danger can arise from the application of gas-lights in any way, but what is common to candle-light, and lamps of all kinds, and is the fault of none of them. Even in this case the gas-lights are less hazardous. There is no risk of those accidents which often happen from the guttering or burning down of candles, or from carelessly snuffing them. The gas-light lamps and burners must necessarily be fixed to one place, and therefore cannot fall, or otherwise become deranged, without being immediately extinguished. Besides, the gas-light flames emit no sparks, nor are any embers detached from them. As a proof of the comparative safety of the gas-lights, it need only be stated, that the Fire-offices engage themselves to insure cotton-mills, and other public works, at a less premium, where gas-lights are used, than in the case of any other lights.[38] The excessive expence of insurance arising from the numerous candles employed in most of the first rate manufactories, and the combustible nature of the structure of the buildings; the great difficulty of retrieving the injury resulting to a well-organised business, from the accidental destruction of the machinery, are objects alone sufficient to furnish the strongest economical, as well as political recommendations, for the adoption of the new lights in all manufactories where work is done by candle-light. [38] Since the preceding pages have been printed, I have seen a _self-extinguishing gas-lamp_, invented by Mr. CLEGG. This lamp is so constructed, that the gas cannot flow to the burner, when the flame becomes extinguished. If, therefore, the lamp should be blown out, and the stop-cock which supplies the gas be left open, the extinction of the flame will effectually shut the valve. The action of this lamp depends upon the expansibility of a metallic rod, heated by the flame of the lamp, and thus keeping open the valve, whereas, when the lamp is extinguished, and the rod becomes cold, it contracts to its natural dimensions, and, by that means, effectually closes the valve. The same engineer has invented a machine, which both measures and registers, in the absence of the observer, the quantity of gas delivered by any pipe communicating with a gas-light main. The machine occupies a space of about two feet by one foot, and, if put up in a room, house, or other place, where gas is burnt, will, at any time, by mere inspection, give an account of the quantity of gas consumed in that place during any given time. On the present occasion, it would not become me to say more on these subjects, which, no doubt, Mr. CLEGG will make known to the public; I shall only remark, that these contrivances do signal honour to the talents and abilities of the inventor; and that they will render the greatest services to those who are engaged in the gas-light illumination.