Candied Fruit.—The " candied-peel " of citrons, lemons, and oranges, is thus prepared. The fruits are placed in vats, and boiled till soft enough to absorb the sugar. The pulp is then entirely removed, and wasted, no attempt having been made to utilize it for the production of essences, or vinegar. The peel is put into tubs, and treated with bet syrup of sugar for 10-14 days. It is then dried on sieves, in a room heated to 38° (100° F.). It is finally candied by immersion in a boiling limpid syrup of sugar, left to drain on a sieve over the pan, and again hot-dried and packed. Whole fruits are prepared in a similar manner.
Meat.—Dr. Richardson says that putrefactive changes in meat are due to the decomposition of the water contained in the tissues. The means which have been found to arrest this decomposition are (1) a low temperature; (2) a high state of desiccation ;. (3) the application of antiseptics ; (4) the exclusion of air.
Refrigeration.—Subjection to a low temperature is a thoroughly effective way of preserving meat, but it can be considered only as temporary, decomposition ensuing when the cold state is abandoned. Nevertheless, its effects are sufficiently lasting to serve practical ends, and the process seems most likely to solve the problem of conveying large quantities of fresh meat to this country. Numerous plans have been devised, all aiming at the production of a sufficiently low temperature at a remunerative cost. The principal are : Harrison's.—The meat is first frozen, and is then packed in a chamber on board ship, the air of which is maintained in a thoroughly dry state, so as to keep up a slow but constant evaporation from the surface of the meat. The meat is placed in tanks, which are kept cool by directing a stream of brine among ice, and regulating the strength of the brine so as to produce the desired degree of cold. The ice and brine are kept in tanks above the meat, and from them streams constantly trickle over and around the meat-tanks. The consumption of ice is less than 50 tons for 50 tons of meat, and the proportion decreases with larger quantities. The meat retains its full flavour, and will keep good in a temperature of 17°40° (63°-68° F.) for 70-80 hours after removal from the tanks. The drawback is the bulk of ice required.
Tellier's.—The joints of meat are placed in a chamber, through which ie passed a current of air charged with ether, or other volatile substance, so as to reduce the temperature sufficiently low to preserve the meat, without freezing its juices.
Mort and Nicol this process, the freezing agent is ammonia solution, under a pressuro of 50-70 lb. a sq. in. The freezing-room is kept below 0° (32° F.), and the meat is frozen quite hard.
Poggiale's.—A low temperature is maintained by the evaporation of methylio ether, and circulation of chloride of calcium.
Bell and Coleman's.—This process is, perhaps, the most completely successful of all that have been introduced, and is equally applicable to the preservation of fresh meat during transport by land or sea, and while being stored. The meat is placed in a chamber, made as nearly air tight as possible, and of the best-known non-conducting materials. The air which ie made to circulate in the meat-chamber is cooled so as to maintain a temperature never exceeding 10° (50° F.), and never so low as to actually freeze tho meat. The cold is obtained by the re-expansion of com pressed and cooled air. Cold-producing machines on this principle are by no means new, but a great difficulty hitherto met with in applying this eyetem has been the formation of particles of ice during the re-expansion. This is avoided by a more effectual cooling of the compressed air, and by subsequently treating the air so as to separate moisture from it, by subjecting it, before re-expansion, to an atmosphere cool enough to ensure the deposition of any remaining moisture that would bo liable to freeze ; moreover, care is taken that the air shall not be so highly dried as to have a desiccating effect upon the meat.
The compression of the air is effected in the apparatus shown in vertical section in Fig. 725. The air enters by pipes a above the cylinders, and through valves b in the upper parts of the cylinder ends ; it passes out through valves c in tho lower parts of the cylinder ends, and by pipes d beneath the oylinders. At each end of each compressing-cylinder c, is fitted up a small pipe f, for injecting water to absorb some of the heat developed during compression : this water drains into the discharge-pipes d, and is led away by pipes g. The compressed air passes from the disoharge - pipes d into the apparatus for completing the cooling and separation of the raoistwe. This apparatus is shown in vertical section in Fig. 726.