per minute respectively for the larger and smaller machines, under
which conditions the delivery of cold air may be taken at about 7,000
and 2,600 cubic feet per hour. Messrs. Hall also make this class of
refrigerator without the steam cylinder, and arranged to be driven by
a belt from a gas engine or any existing motive power.

* * * * *




A GAS RADIATOR AND HEATER.


[Illustration: Fig. 1 & Fig. 2 A GAS RADIATOR AND HEATER.]

There is now being introduced into Germany a gas radiator and heater,
the invention of Herr Wobbe. It consists, as will be seen in engraving
above, of a series of vertical U-shaped pipes, of wrought iron, 50
millimeters (2 inches) in diameter. The two legs of the U are of
unequal length; the longer being about 5 feet, and the shorter 3 feet
(exclusive of the bend at the top). Beneath the open end of the
shorter leg of each pipe is placed a burner, attached to a horizontal
gas-pipe, which turns upon an axis. The object of having this pipe
rotate is to bring the burners into an inclined position--shown by the
dotted lines in Fig. 2--for lighting them. On turning them back to the
vertical position, the heated products of combustion pass up the
shorter tube and down the longer, where they enter a common
receptacle, from which they pass into the chimney or out of doors.
Surrounding the pipes are plates of sheet iron, inclined at the angle