The "Mechanical World" recently contained an epitome of a lecture by A. B. .Roxburgh of the National Gas Engine Company, Ltd., in which it was stated that about one-fourth of all the gas made in Great Britain is employed in driving gas engines. The lecturer estimated that in the United Kingdom alone there are manufactured at least 200 gas engines per week. Averaging them at the very low size of 10 h. p. each would give a weekly production of 2000 brake h. p. It was deemed likely, however, that the actual amount is double that figure.

Only the very best copper and the highest refined spelter are ever put into cartridge brass. The requirements are such that other metals will not answer the purpose. The standard mixture is two parts of copper and one part spelter.

The " Pyrophone " is a new automatic fire detector, for which it is claimed that it makes the detection of fire in its earliest stage certain, makes false alarms impossible, gives a "danger call" preceding each fire call, and requires no fixed degree of temperature in order to give the alarm. The apparatus consists of a small U-shaped glass tube half filled with mercury in each end. One branch of the tube is exposed, while the other is covered with insulating material. When there is a sudden rise of temperature the liquid in the non-protected branch expands, thus driving the mercury downwards below a platinum wire which enters the tube and causes a danger signal. If the rise of temperature contiuues the mercury still falls lower, and below another platinum wire, breaking the circuit and causing a fire alarm. The indicator board shows "trouble" "danger," "fire, " "earth" and " battery " disks, thus providing for every emergency.

Gasoline, like all other products of crude petroleum, was for a long time disposed of as waste in the effort to make kerosene. It is the first and highest distillant of crude petroleum. Gasoline is extracted by distillation just as whiskey is produced and in much the same kind of apparatus.

Each watch movement requires from 30 to 50 screws. By the earlier methods a skilled workman could make 700 to 1200 screws daily. Automatic machines now produce from 4000 to 10,000 screws per day, and one man can operate six machines.

Water, though colorless when in small quantities, is blue like the atmosphere when viewed in mass.

When water passes from the liquid to the solid state it expands to the amount of about 1 -11th of its volume.