Report on the American and Canadian Meat Trade. 349 
"The method applied for producing the desired temperature is simplicity 
itself. There is an entire absence of the chemical processes employed in 
artificial freezing, such as ether, ammonia, hydro-sulphuric acid, or the salts 
of potash or ammonia. All that is used is a simple mechanism for compressing 
the ordinary atmospheric air, and subjecting it, whilst under pressure, or 
rather while it is in the act of expanding from pressure, to the action of a jet 
of cold water, which, thrown suddenly upon the air deprives it of its heat, 
and the atmosphere thus cooled passes into the chamber the temperature of 
which it is iutended to reduce. A retort from which to draw the air to he 
operated upon, a couple of cylinders for compressing, a small pump to suppl}- 
the stream of water, and a freezing-chamber are in reality all the mechanism 
used in the combination, with, of course, the ordinary motive-power. The 
idea of compressing air for cooling purposes is not new ; but it is only of late 
years that it has been brought into practical operation. The inventors of the 
machine under notice are Messrs. Giffard and Berger, of Paris, the first-named 
gentleman bcingabrother of the celebrated aeronaut of that name, and inventor 
of Giffard's Injector. The machine we have had the opportunity of inspecting 
has been erected (in a temporary building near the Municipal Offices) merely 
for trial purposes, and of course could not be judged of under favourable cir- 
cumstances, the freezing-chamber being of wood, and the room in which it 
stands not being sufficiently protected from the entrance of the external 
atmosphere. The results, however, were surprising. In half an hour after 
commencing to work the machine, the thermometer within the freezing- 
chamber stood at 20° below zero ; the interior of the chamber was covered 
with hoar-frost half an inch thick, bottles of water were frozen solid, and the 
general temperature of the room in which the freezing-chamber stands was 
reduced to 30° Fahrenheit, or the freezing-point. The longer of course the 
cooling process in continued, the more the temperature of the room receiving 
the cold air will be lowered, as the atmosphere thus ratified is capable of being 
pumped back into the retort, and is necessarily more susceptible to the treat- 
ment employed than the external air. Generally the cooled air is delivered 
into the room 50° below the outside temperature, and the cold can be main- 
tained at an average of 15° Fahrenheit, or above or below that temperature as 
required. A machine of the size of the one alluded to is capable of being 
worked by an engine of five-horse power, and will distribute 300 cubic metres 
of air per hour. Ordinarily the air discharged from the refrigerator is moist, 
but by a simple contrivance it can be rendered quite dry. 
" One of the advantages claimed for the invention is that it will produce ice 
much cheaper than any other refrigerating process at present in use, and in 
this respect its economical benefits must commend themselves. But the more 
obvious uses to which it can be applied, and which have called forth its 
present introduction, are in connection with the fresh-meat trade already 
referred to. If the machine is capable of what is stated, its superior applica- 
tion to the preservation of fresh meat on board the Atlantic steamers is 
apparent, and it is expected before long that it will supersede the present 
appliances. With that view a company is being formed in London, the pro- 
moters being Messrs. Gittins and Company, the immediate object of the 
undertaking being to import large quantities of beef, mutton, poultry, game, 
<fec, from Canada and the United States, for the metropolitan and other 
wholesale markets. The promoters will add to their facilities by having 
depots in Liverpool and London, each fitted up with the refrigerators, so that 
every facility will be had for keeping the meat fresh and good for a sufficient 
length of time. There are, however, numerous other objects to which the 
invention can be beneficially applied ; in short, its utility will be obvious in 
all cases in which a low and regulated temperature is required. For instance, 
it is adaptable for keeping cabins and engine-rooms cool in hot climates, for 
