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faces and perform mostly out-and-home journeys. Nevertheless, absorbed acetylene may claim close attention for one department of household illumination, viz., the portable table-lamp; for the base of such an apparatus might easily be constructed to imitate the acetone cylinder, and it could be charged by simple connexion with a larger one at intervals. In this way the size of the lamp for a given number of candle-hours would be reduced below that of any type of actual generator, and the troubles of after-generation, always more or less experienced in holderless generators, would be entirely done away with. Dissolved acetylene is also very useful for acetylene welding or autogenous soldering.
The advantages of compressed and absorbed acetylene depend on the small bulk and weight of the apparatus per unit of light, on the fact that no amount of agitation can affect the evolution of gas (as may happen with an ordinary acetylene generator), on the absence of any liquid which may freeze in winter, and on there being no need for skilled attention except when the cylinders are being changed. These vessels weigh between 2.5 and 3 kilos, per 1 litre capacity (normal) and since they are charged with 100 times their apparent volume of acetylene, they may be said to weigh 1 kilo, per 33 litres of available acetylene, or roughly 2 lb. per cubic foot, or, again, if half-foot burners are used, 2 lb. per 36 candle- hours. According to Fouché, if electricity obtained from lead accumulators is compared with acetylene on the basis of the weight of apparatus needed to evolve a certain quantify of light, 1 kilo, of acetylene cylinder is equal to 1.33 kilos, of lead accumulator with arc lamps, or to 4 kilos. of accumulator with glow lamps; and moreover the acetylene cylinder can be charged and discharged, broadly speaking, as quickly or as slowly as may be desired; while, it may be added, the same cylinder will serve one or more self-luminous jets, one or more incandescent burners, any number and variety of heating appar