It has been well said that "Necessity is the mother of invention." Cold storage of the present time is understood as "mechanical refrigeration," and in general, the preservation of perishable articles by means of low temperature, hence, the act of reducing the temperature of any body, or maintaining the same below the temperature of the atmosphere, is called refrigeration, or more familiarly known as cold storage, produced by the employment of machinery of various types. Of those mostly in use, are the compression system, using anhydrous ammonia as a refrigerant, by expanding the ammonia either directly through coils of pipe arranged in the storage rooms, or through coils of pipe that are submerged in salt brine, where the brine is reduced to a low temperature and then forced and circulated through pipes in the storage rooms, one being known as direct expansion, the other, brine circulation, but both accomplish same results.

To utilize anhydrous ammonia requires complicated and expensive machinery, and to those not acquainted with the subject it may seem strange that more units of heat are produced by the burning of coal, wood or oil than there are units of cold produced to reduce the temperature of storage rooms.

Of the uses and benefits of cold storage it can be truthfully stated, that nothing in recent years has been of more direct benefit to the farmer, stock-raiser, and fruit-grower. But a brief period has passed since cellars, caves and underground grottos served as the best means, and in a limited way under certain conditions of weather, for the protection and preservation of perishable articles.

To-day machinery has made it possible to control temperature at any degree and in all climates. The burning heat under the equator would not be an impediment to secure a zero temperature in a cold-storage room.

The construction and successful operation of the mammoth packing-houses are the outgrowth of the success of the application of mechanical refrigeration, where any day of the year a market is made for live stock. But few years have elapsed since the vast herds of South American cattle had no value, except for their hides, horns, and tallow, and the great bands of Australian sheep for their wool. Now immense refrigerating plants are in operation, freezing the beef and mutton, with fleets of ocean steamers equipped with refrigerating machinery and storage rooms filled with frozen meat for European markets. From the United States the dressed-beef traffic is of large proportions. Storage speculators are always ready buyers at remunerative prices for butter and eggs, that in value exceed the great wheat crop of America.

To fruit-growers, especially those engaged in apple culture, cold storage is attracting more than common interest, as it has been demonstrated a grand success in the preservation of apples from three to six months longer, in good condition, than in natural storage that is subject to the changeable influences of the atmosphere. At the same time, the apples retain their original and individual flavor, color, and crispness.

Cold storage, or mechanical refrigeration, arrests fermentation and decay, or, better stated, prolongs the life and keeping qualities.

Of the advantages gained, it offers a place of safe-keeping for future market, and affords a protection for the grower if market conditions are not favorable; such as an overstocked market, consequently low prices, caused largely and influenced by many other varieties of fruit that are in season while the apple crop is being gathered.

Again, the fact of the existence of cold-storage houses has brought into the field speculators, which has a wholesome influence, and oftentimes strengthens the markets and lessens the quantity that would of necessity be forced on sale at an earlier period at a great sacrifice, which is the situation this year, where the enormous crops of New York, New England and Michigan apples are being sold at from fifty to seventy-five cents a barrel (including barrels) placed aboard cars, for the want of proper and sufficient storage facilities to relieve part of the burden. No such condition or low price has yet been felt by the Western grower.

There may be years when the buyers will look far into the future and think they can see visions of long prices, when it would be wise for the growers to sell, as there is some risk to be taken as to future markets being lower than prices in the fall, but such is not the rule.