is increased 18 per cent. in a vertical line and 55 per cent. at 80°, which is a highly satisfactory result. There are at present five sizes of these lamps. There is also the Delmas hot air burner, in which the batswing flame is completely inclosed in a glass, mounted with a sheet-iron casing, heated by the products of combustion, through which the air passes on its passage downward to feed the flame; and it thus increases the temperature, improves the illuminating power, and produces a beautiful steady light. Mention also may be made of the Siemens radiated heat burner, by means of which the heating of the air is effected simply by the radiation of the metallic parts of the appliance which are in contact with the flame. These burners produce the light of 1 carcel (9.5 candles) with a gas consumption of 70 liters (about 2½ cubic feet), and are therefore, from an economical point of view, intermediary between the high power and regenerative burners. This degree of economy can be ascertained by an ingenious arrangement of the air supply in a burner with holes, which has been made in the laboratory of the Wazemmes Gas Company by M. Verlé, the engineer, who has invented a very simple burner called the "Lillois," with which the light of 1 carcel is obtained with a consumption of 70 liters. This produces a tulip-shaped flame, and it has a specially constructed glass arrangement on the outside for regulating the combustion. Comparing the above-mentioned burners with each other, we arrive at the following results: The "Lillois" burner consumes 70 liters of gas per carcel; the Siemens ordinary, 70 liters; the Siemens-Breittmayer, 35 to 39 liters; the Wenham, about 35 liters. Taking this into account, and considering that a carcel corresponds with 105 liters of gas consumed in the Bengal form of burner, we see that the economy in gas might, by employing these burners, reach from 33 to 71 per cent. If this is compared with the batswing burner, which produces the light of 1 carcel with a consumption of 120 liters of gas, the economy is greater--varying, according to the type of lamp, from 41 to 85 per cent. * * * * * SYNCHRONIZING CLOCKS. [Illustration: DAVEY'S PENDULUM FOR SYNCHRONIZING CLOCKS. W, friction wheel attached to pendulum. L gives no impulse except when the electro-magnet is excited. K, lever and weight lifted by electro-magnet, E. A, open contact completed by pendulum each swing. B, battery. R, ratchet wheel and pawl. M, lever fixed at top. L, weight at end of bell crank lever, which drives pendulum once each minute, being raised by the electro-magnets.]