higher than the storage room, and a coil of pipe is placed in this tank and another in the storage room. The two coils are connected and are filled with a solution of calcium chlorid. The tank is filled with ice and salt. The brine in the tank coil is cooled more than the brine in the storage room coil. It

24 RAFTERS-18 OC 13 STRIPS ON RAFTERS

Fig. 350. Section of roof over cooling room.

flows downward because of the heavier specific gravity, forcing the warm brine back to the tank coil. This automatic circulation continues as long as the temperature in the storage room is warmer than the mixture of ice and salt. The temperature in this system is under control. It can be varied by changing the proportions of ice and salt, the size of the tank and the number of coils in the storage room. If the brine in the pipes is below 32° the moisture of the storage room is frozen on the pipes, making a comparatively dry air. The humidity can be controlled further by exposing calcium chlorid over the pipes. The temperature can be maintained uniformly in all parts of the storage rooms after the grower learns to manage the plant. It has all the advantages of chemical storage so far as low temperature and dry air are concerned, and none of the disadvantages arising from the handling of complicated machinery. The first cost of a building is greater than an ice-cooled or an ice-and-salt plant. It is managed more easily than either and at no greater cost, while the efficiency is much greater. This is probably the best type of farm storage building when ice can be secured. A building of this type is shown in Figs. 352, 353, 354.

A building cooled by means of chemicals.

Farm storage plants are sometimes cooled by ammonia or by some other gas on the same principle as the refrigeration of large commercial cold storage warehouses. This system is expensive to install. It requires expert management. It may be used to best advantage in the warmer apple-growing sections. This system, however, is out of the reach of the average fruit-grower unless it can

have the same efficient care that a commercial warehouse receives. There are several of these plants in use on fruit-farms. Some of them are unsatisfactory because the installation has been too cheaply done and the management is not sufficiently expert. Under good management, however, a chemically-cooled plant may give ideal storage conditions on the farm.

Requirements in a farm storage building.

Farm storage buildings vary widely in size and cost, construction, arrangement and in other details. They may be built separately or as a part of a building already constructed. All types, except the common storage and the chemically-cooled storage buildings, need to be connected with an icestorage space which may be a part of the storage building or detached from it. Because of leakage, the ice for the entire season should not be stored above the fruit rooms. All farm storage houses should be provided with a packing room, a storage room for packages and an ante-room or cooling room opening into the storage rooms to prevent the direct access of warm air to the cold rooms. If the building has a capacity of 500 barrels, it should be divided into two rooms to avoid moving warm fruit into the same room throughout the harvesting season. In addition, all farm storage buildings should have thorough systems of ventilation, so as to utilize natural refrigeration by opening the doors and ventilators during the fall to let the fresh air flow into the rooms when the temperature is cold enough. Plans of a gravity-brine cold-storage house are shown in Figs. 353 and 354. The floor plan of this house is adapted to an ice-cooled or an iceand-salt plant.

The size and cost.-A space of 8 cubic feet is usually allowed for a barrel of apples, including the spacing for ventilation. By storing fruit in square packages, the capacity of a room is increased 10

2.4-18′′OC

Fig. 351. Section of roof over ice storage.

to 15 per cent over barrels, and by storing in bulk the capacity is increased still more. Some space has to be allowed for corridors between the packages in large rooms. A room 40 x 30 x 7 feet will

store approximately 1,000 barrels; one 40 x 40 x 10 feet will store 2,000 barrels, the extra spacing being used by corridors between the packages. A room should not be over 10 to 12 feet in height. A building with 100 barrels capacity can be maintained with a fair degree of success, but the cost of small buildings is proportionally high. A farm

Fig. 352. Gravity-brine cold-storage house. storage building should seldom have less than 500 barrels capacity.

The cost of the building can be approximated only in a general way, as it is influenced by the construction and by local conditions. A common storage house of 1,000 barrels capacity, one story high, frame, with packing room and storage space for packages, can be built at a cost ranging from $800 to $1,500; a well-built ice- or ice-and-saltcooled storage plant of the same capacity, including the ice-house, for $1,500 to $2,000; a gravitybrine plant for $2,000 to $3,000; and a chemically cooled plant for $5,000. Larger buildings are proportionally cheaper to construct. An ice-cooled plant of 2,000 barrels capacity can be built for $3,000 to $3,500; a gravity-brine plant for $3,500 to $4,500; while a chemically-cooled plant of 5,000 barrels will cost $7,500 to $12,000.

Construction.-The fundamental requirement in the construction of farm storage buildings is efficient insulation in every part. A uniform temperature is impossible with cheap construction and poor insulation. It is not economy to restrict the first cost of the building too rigidly. The construction is subject to a wide variation in materials and in their arrangement. The material may be brick, concrete, stone or wood. The use of dead-air spaces is the most effective method of insulation. In order to break up the air currents in the space, one of the spaces should be filled with some fine

material, such as mineral wool, fine shavings, sawdust, or fine dry cinders. The insulation should always be dry, as a wet filling is worse than none. A dead space should be built on each side of a filled space, or non-conducting materials like P. & B. papers or hair felt used in connection with the board walls. Common storage buildings do not require such perfect insulation.

Location of the ice-chamber.-In an ice-cooled house, the ice-chamber should be located above the storage rooms. It should be built of galvanized iron, and provision made to carry off the water. It may be an insulated box with ventilation on the top, or open if the roof of the building is heavily insulated. It may extend the entire length of the building, but does not need to be more than onehalf the width. The cold air may flow through openings in the ceiling at the side of the ice- tank to the rooms below, and the warm air return up the side of the walls of the storage room; or the current is sometimes reversed, the cold air being led down along the walls behind guides and returning through the center of the room. An effective method of distributing the cold air uniformly is made by building a slat oak floor to the ice-box, which rests on 14-inch joists, one foot apart, supported by a girder and posts. The joists are protected from the water by galvanized iron caps, which drain into galvanized iron troughs hanging between the posts. The troughs lead to galvanized iron gutters, from which the water is drained out of the building. The cold air drops directly through the fruit, is deflected toward the walls and rises back of a false ceiling to the top of the ice-box, which has solid sides. This arrangement is shown in Fig. 349.

Refrigeration. The amount of refrigeration required for running a plant can be approximated only in a general way. It depends on the outside temperature, the construction of the building and other factors. A well-built farm storage house of 1,000 barrels capacity in New York will require the storage of 100 to 175 tons of ice in an ordinary season. Twenty-five to 30 tons of ice will be required to lower the temperature of the fruit to the desired degree of cold, the remainder of the ice being used in the refrigeration of the building and in shrinkage during storage. A house of 2,000 barrels capacity will use 60 to 75 tons in cooling the fruit, and 40 to 75 tons for additional refrigeration and shrinkage. These figures assume first-class insulation and an effective design. A larger quantity will be required for poorly constructed or badly arranged buildings.

If ice alone is used for cooling, the ice box above the fruit storage room should have a capacity of not less than 1 to 13 cubic feet for every barrel of apples, or for every 8 cubic feet of space in the

storage room. The ice tank will need to be iced about once a month during the fall. It is still more difficult to estimate the piping needed in ice-andsalt-cooling. A temperature of 32° can be maintained by using six inches of 10-inch pipe for every barrel, or for 8 cubic feet of space in the storage room; i. e., a room 15 x 15 x 10 feet, which would hold about 280 barrels, would require 16 pipes 9 feet long. In cooling the fruit, 5 to 7 per cent of salt is mixed with the ice, smaller quantities being used after the fruit is cold. A gravity-brine plant of 1,000 barrels capacity will require the storage of about 100 to 175 tons of ice. The proportions of salt and ice are similar to those used in the tube system, though in either the proportions will need to be determined by a few days of experimental work when the plant is started.

Ventilation. An adequate ventilating system is essential to all kinds of farm storage buildings. The methods are subject to wide variation. In common storage houses, the intake of cold air is at the bottom of a room, and the outlet at the top of the building. The cold air at the bottom may be distributed by flues under the floor and let in through registers. The top needs a ventilator for every 12 to 16 feet of length. The ventilator at the roof may be 12 inches square, and should extend 6 to 10 feet above the roof. The ventilators are opened at night and are closed during the day. When the nights are frosty the doors and windows may be opened. Farm storage houses should be provided with grated iron doors for use at night, and the windows of the common storage houses also. Coldstorage houses, that is, those cooled by other means than ventilation with outside air, do not require windows. The circulation of air can be hastened by installing an exhaust fan at the outlet ventilator. In ice-cooled storage, and in the other types

Fig. 354. Horizontal section of a gravity-brine cold-storage house. This floor plan is adapted to an ice- or ice-and-saltcooled plant.

paper covered with one-inch boards. Outside the studding should be nailed one-inch boards, twoply paper, a seven-eighths-inch air space allowed, followed by paper, and tongue-and-grooved siding. The air space may be filled with cork-dust, shavings or mineral wool. The roof should have 2 x 4-inch rafters, with one-inch boards, two-ply paper, a seveneighths-inch air space extending nearly to the peak, and shingles. The seven-eighths-inch air space of the wall should be continuous with the space in the roofing, as shown in Figs. 350 and 351, which show the construction of the walls and roof of a fruit storage and an ice storage house. The gables and the roof should both have ventilators, and the bottom should be tight to prevent the entrance of warm air.

The fruit storage building.

The building should have a good concrete foundation covering the entire floor, or a free air space under the floor, to prevent the insulation of the floor becoming damp. A well-insulated wall may be built like the wall of the ice-house described in the preceding paragraph (Figs. 350 and 351), with the addition of one more dead-air space, one thickness of building-paper and one thickness of sheathing to the inside of the wall. Another wall may be built with 2 x 12-inch studding filled with shavings and protected with boards, building-paper, and siding outside, and boards, building-paper, hair felt, P. & B. building-paper, hair felt, building-paper and boards, in order, inside. The same general construction is used in the floor and ceiling or in the roof in ice- or ice-and-salt-cooled buildings.

A common storage building should have two good air spaces protected with boards and buildingpaper, but the filled space in the center is not essential. The floor and ceiling should be of the same type.

The handling of a farm storage plant.

The successful handling of a farm storage building is a matter of the careful adjustment of many factors on the part of the owner. The keeping of the fruit depends on the conditions in which it is grown, the handling it receives before it is stored and the conditions in the storage plant. The influence of cultural conditions on the keeping of the fruit is not well understood. It is probable that any condition that causes the fruit to grow with unusual rapidity, such as excessive culture or richness in the soil, a light crop, young rank-growing trees, or quick-acting light soils, is likely to reduce the length of the storage life of the fruit.

Of greater practical importance is the handling of the fruit after it is picked and before it is stored. The common soft rots in apples gain entrance through an abrasion in the skin and grow vigorously if the temperature is not reduced quickly. Other troubles, as the bitter-rot and pink-mold, grow rapidly after picking if the temperature is not reduced quickly to 40° Fahr. Sound fruit and quick storage are fundamentals in successful fruit storage. The owner of the farm storage plant should aim to place the fruit in the storage room within twenty-four hours after picking, leaving the fruit in the cooler air the night following picking.

A variety of packages may be used for storing the fruit. All of these need a circulation of air around them for rapid cooling. Quick-ripening fruits should be stored in small packages in order that the contents may be cooled quickly. In an ice-cooled house where the air is moist, apples may be stored in bins, though the fruit is likely to shrivel if stored in bulk or in open packages in temperatures as low as 32°. A wrapper improves the keeping of all fruits that are to be held for any length of time. It preserves the flavor, prevents the spread of disease and protects the fruit from mechanical injury.

The storage rooms should be kept as near 32° as possible for all fruit products. A temperature somewhat higher keeps the fruit fairly well, especially if it is stored quickly after picking; but if the storage is delayed in hot weather, or if the fruit is intended for a long keeping period, the lower temperature is needed for the most satisfactory results. Frequent ventilation with cold air is essential to the preservation of the quality of the fruit.

Literature.

The literature of cold-storage is scattered, yet the subject is of great importance to modern agriculture, in the storage of fruits, eggs and meats. Because of this scattered literature, a rather full bibliography is here given:

General storage and refrigeration.-Refrigerating and Ice-making Machinery (2d ed.; pp. 280), A. J. Wallis-Tayler, London, 1897; Machinery for Refrigeration, Norman Selfe, Chicago, 1900; Eggs in Cold Storage (pp. 88), Madison Cooper, Chicago, 1899; Principles and Practice of Artificial Ice-making and Refrigeration (pp. 232), Louis M. Schmidt, Philadelphia, 1900; Ice Cold Storage (pp. 47), Madison Cooper, Minneapolis, 1901; Practical Cold Storage (pp. 600), Madison Cooper Co., Chicago, 1905.

Fruit and vegetable storage. - Article on ColdStorage, L. C. Corbett, Cyclopedia of American Horticulture; Apple-Growing in Grand Isle County, Vt. (pp. 83-95), F. A. Waugh, Bulletin No. 55, Vermont Agricultural Experiment Station, 1896; Cold Storage for Fruit (pp. 31), E. E. Faville and W. L. Hall, Bulletin No. 84, Experiment Station, Kansas State Agricultural College, Manhattan, Kans., April, 1899; Storage of Apples, Herbert H. Lamson, (pp. 25-29), Bulletin No. 79, Agricultural Experiment Station, New Hampshire College of Agriculture and the Mechanic Arts, Durham, N. H., November, 1900; The Influence of Refrigeration on the Fruit Industry (reprint from Year-book of Department of Agriculture for 1900), pp. 561-580, William A. Taylor; Cold Storage (pp. 51-79), L. C. Corbett, Bulletin No. 74, Agricultural Experiment Station, West Virginia University, Morgantown, W. Va., March, 1901; Protection of Food Products from Injurious Temperatures (pp. 26), H. E. Williams, Farmers' Bulletin No. 125, United States Department of Agriculture, Washington, D. C., 1901; Fruit-Storage Experiments (pp. 18), Circular No. 44, Agricultural Experiment Station, University of Illinois, Urbana, Ill., February, 1902; Cold Storage of Fruit (pp. 8), J. B. Reynolds and H. L. Hutt, Bulletin No. 123, Ontario Agricultural College, July, 1902; The Cold Storage of Apples (pp. 88), F. Wm. Rane, Herbert H. Lamson and Fred W. Morse, Bulletin No. 93, Agricultural Experiment Station, New Hampshire College of Agriculture and the Mechanic Arts, Durham, N. H., October, 1902; Fruit and Orchard Investigations (pp. 27), Circular No. 67, Agricultural Experiment Station, University of Illinois, Urbana, Ill., February, 1903; Two Decays of Stored Apples (pp. 123-131), H. J. Eustace, Bulletin No. 235, New York Agricultural Experiment Station, Geneva, N. Y., July, 1903; Cold Storage, With Special Reference to the Pear and Peach (pp. 26), G. Harold Powell and S. H. Fulton, Bulletin No. 40, Bureau of Plant Industry, United States Department of Agriculture, Washington, D. C., September 18, 1903; Cold Storage of Apples (pp. 44), H. C. Price, Bulletin No. 72, Experiment Station, Iowa State College of Agriculture and the Mechanic Arts, Ames, Ia., October, 1903; Relation of Cold Storage to Commercial Apple Culture (pp. 225-238), reprint from Year-book of Department of Agriculture for 1903 (pp. 225-238), G. Harold Powell, Washington, D. C.; New York Apples in Storage (pp. 83-152), S. A. Beach and V. A. Clark, Bulletin No. 248, New York Agricultural Experiment Station, Geneva, N. Y., March, 1904; The Apple in Cold Storage (pp. 66), G. Harold Powell and S. H. Fulton, Bulletin No. 48, Bureau of Plant Industry, United States Department of Agriculture, Washington, D. C., December 3, 1903 (Revised February 1, 1905).

Statistical and legal.-Warehousing Industry in the United States (pp. 1035-1095), Bureau of Statistics, United States Department of Commerce and Labor (from the Summary of Commerce and Finance for October, 1903); Mohun on Warehousemen (pp. 948), Barry Mohun, The Banks Law Publishing Company, 21 Murray St., New York, 1904.