oxygen, and a red-hot iron
wire thrust into the liquid burns and spreads sparks of iron. But more
novel still was Dewar's experiment of inserting a small jet of ignited
hydrogen into the vessel of liquid oxygen; for the jet continued to
burn, forming water, of course, which was carried away as snow. The idea
of a gas-jet burning within a liquid, and having snow for smoke, is
not the least anomalous of the many strange conceptions that the
low-temperature work has made familiar.

PRACTICAL RESULTS AND ANTICIPATIONS

Such are some of the strictly scientific results of the low-temperature
work. But there are other results of a more directly practical
kind--neither more important nor more interesting on that account, to
be sure, but more directly appealing to the generality of the
non-scientific public. Of these applications, the most patent and the
first to be made available was the one forecast by Davy from the very
first--namely, the use of liquefied gases in the refrigeration of
foods. Long before the more resistant gases had been liquefied, the more
manageable ones, such as ammonia and sulphurous acid, had been utilized
on a commercial scale for refrigerating purposes. To-day every
brewery and every large cold-storage warehouse is supplied with such
a refrigerator plant, the temperature being thus regulated as is not
otherwise practicable. Many large halls are cooled in a similar manner,
and thus made comfortable in the summer. Ships carrying perishables
have the safety of their cargoes insured by a refrigerator plant. In all
large cities there are ice manufactories using the same method, and of
late even relatively small establishments, hotels, and apartment houses
have their ice-machine. It seems probable that before long all such
buildings and many private dwellings will be provided with a cooling
apparatus as regularly as they are now equipped with a heating
apparatus.

The exact details of the various refrigerator machines of course vary,
but all of them utilize the principles that the laboratory workers first
established. Indeed, the entire refrigerator industry, now assuming
significant proportions, may be said to be a direct outgrowth of that
technical work which Davy and Faraday inaugurated and prosecuted at the
Royal Institution--a result which would have been most gratifying to the
founder of the institution could he have forecast it. The usual means
of distributing the cooling fluids in the commercial