lay down than an apparatus composed of tinplate, zinc, or thin galvanised iron, but it will prove more economical in the long run. It is not too much to say that if ignorant and short-sighted makers in the earliest days of the acetylene industry had not recommended and supplied to their customers lightly built apparatus which has in many instances already begun to give trouble, to need repairs, and to fail by thorough corrosion--apparatus which frequently had nothing but cheapness in its favour--the use of the gas would have spread more rapidly than it has done, and the public would not now be hearing of partial or complete failures of acetylene installations. Each of these failures, whether accompanied by explosions and injury to persons or not, acts more powerfully to restrain a possible new customer from adopting the acetylene light, than several wholly successful plants urge him to take it up; for the average member of the public is not in a position to distinguish properly between the collapse of a certain generator owing to defective design or construction (which reflects no discredit upon the gas itself), and the failure of acetylene to show in practice those advantages that have been ascribed to it. One peculiar and noteworthy feature of acetylene, often overlooked, is that the apparatus is constructed by men who may have been accustomed to gas-making plant all their lives, and who may understand by mere habit how to superintend a chemical operation; but the same apparatus is used by persons who generally have no special acquaintance with such subjects, and who, very possibly, have not even burnt coal-gas at any period of their lives. Hence it happens that when some thoughtless action on the part of the country attendant of an acetylene apparatus is followed by an escape of gas from the generator, and by an accumulation of that gas in the house where the plant is situated, or when, in disregard of rules, he takes a naked light into the house and an explosion follows, the builder dismisses the episode as a piece of stupidity or wilful misbehaviour for which he can in nowise be held morally responsible; whereas the builder himself is to blame for designing an apparatus from which an escape of gas can be accompanied by sensible risks to property or life. However unpalatable this assertion may be, its truth cannot be controverted; because, short of criminal intention or insanity on the part of the attendant, it is in the first place a mere matter of knowledge and skill so to construct an acetylene plant that an escape of gas is extremely unlikely, even when the apparatus is opened for recharging, or when it is manipulated wrongly; and in the second place, it is easy so to arrange the plant that any disturbance of its functions which may occur shall be followed by an immediate removal of the surplus gas into a place of complete safety outside and above the generator-house.