388 



THE GARDENER'S ASSISTANT. 



chiefly applied to the preservation of meat, yet 

 experiments with fruits have in several instances 

 given encouraging results. In one case recently 

 the Technical Education Committee of the Kent 

 County Council undertook some experiments 

 with various soft fruits at the cold-storage 

 works in Dartford, and Mr. W. P. Wright 

 prepared a report of the results, which pointed 

 out the practicability and probable commercial 

 advantage of the system. The fruits tried 

 were Strawberries, Black Currants, Red Cur- 

 rants, and Cherries, which were placed on wire 

 shelves in three chambers in which tempera- 

 tures were maintained varying in different 

 instances from 26° to 42°. As regards the 

 Strawberries, it was found that " the fruit 

 cannot be kept long in a temperature of 36° 

 or upwards; it can be kept for three weeks at 

 least in a temperature of 30°; it is necessary to 

 surround the fruit with cotton-wool, or in the 

 case of fruit in sieves, to place a pad of that 

 material over the top. If this precaution is 

 not taken, the fruit though sound becomes dull, 

 and loses the fresh, inviting appearance which 

 is so important when it is offered for sale." 



The results of these experiments are sum- 

 marized as follows: — (i) The fruit must be 

 placed in store in advance of dead ripeness. 

 This is particularly the ease with Strawberries. 

 Fruits that are fully ripe will keep for some 

 time, but lose surface freshness, (ii) It is use- 

 less to put injured fruit in store. Cherries 

 pecked by birds soon go off, and other fruits 

 impaired in any way will not keep. To achieve 

 success the fruit must be sound. (iii) The 

 fruit should be covered or surrounded with 

 cotton-wool. It was observable that fruit so 

 treated retained its freshness much longer than 

 that left exposed, (iv) The chambers must be 

 kept dry, and close-fitting doors are necessary, 

 otherwise damp and gritty impurities find en- 

 trance, (v) All decaying or impure matter 

 must be rigidly excluded. 



The directions given for the preparation of 

 some fruits for cold storage in the United States 

 are: — 



1. The fruit when packed should be fully 

 grown but not quite ripe. 



2. Such fruits as Pears, Peaches, and large 

 Plums should be wrapped separately in tissue- 

 paper. 



„ 3. Wooden boxes are preferable to baskets in 

 which to place the fruit for storage. 



4. Such fruits as Peaches and Plums cannot 

 be relied upon to store longer than two or three 

 weeks. 



5. Early Apples and Pears may be stored four 

 to six weeks and even longer. [j. craig.] 



The systems adopted for obtaining the neces- 

 sary temperatures are usually modifications of 

 one of three methods most generally employed 

 in America, namely, (i) direct expansion, by 

 the use of either carbonic anhydride, i.e. car- 

 bonic-acid gas, or anhydrous ammonia; (ii) 

 brine circulation or indirect expansion, and 

 (iii) air circulation. 



Machinery is employed to effect the com- 

 pression, condensation, and expansion of the 

 gas used (see Plate), and the principle de- 

 pended upon is the power of a compressed 

 cooled gas to withdraw from surrounding ob- 

 jects a great amount of heat when it is allowed 

 to expand. Pipes are taken round the sides 

 and along the ceilings of the chambers to carry 

 the expanding gas, and a similar arrangement 

 is made in the indirect or brine system, but in 

 this the gas is employed first to cool the solu- 

 tion of salt, which is then forced to circulate 

 through the pipes at the rate of about sixty 

 feet per minute. Almost any temperature suit- 

 able for preservation purposes can thus be 

 obtained, and the system is adapted to railroad 

 cars, storage-chambers on ship-board, and to 

 large central permanent storages for food 

 supplies. 



The installation of a method of this kind is 

 especially adaptable for working either on the 

 co-operative principle or by companies, who pre- 

 pare a list of prices for different food products 

 according to the length of time they are desired 

 to be stored. In Chicago, for instance, the 

 charges are by the week, first, second, or third 

 month, or season; thus, for Apples, the charge 

 per barrel is 25 cents the first month, 15 cents 

 the second, and 10 cents the third, or 50 cents, 

 i.e. 2s. Id., for the season; Pears are charged 

 30 cents per barrel for a month, Plums are 

 6 cents a bushel for a month, Raspberries 12J 

 cents a bushel for a week, and Strawberries 

 h cent per quart for a month. It will be seen 

 that if such rates were obtainable here, and 

 the fruit could be kept in good condition, as 

 there is ample evidence that it can, the re- 

 sults might prove extremely advantageous to 

 numbers of growers who are at times over- 

 burdened with heavy crops of perishable fruits. 



[r. l. c] 



