HORTICULTURE 139 



of the warehouseman to the man who stores the fruit, as well as the 

 function of the warehouse in the preservation of the fruit, is not gen- 

 erally understood. The warehouse is supposed to supply a uniform 

 temperature of the desired degree of cold through its rooms during 

 the storage season. It is expected to be managed in other respects 

 so that the deterioration of the fruit and losses from any other cause 

 may not be reasonably attributed to a poor construction or installa- 

 tion of the plant, to its negligent or improper management, or to 

 the ill-treatment of the goods within the warehouse. 



If the temperature of the rooms fluctuates unduly from the de- 

 gree to be maintained and the fruit is frozen to a point of injury, if it 

 ripens with abnormal rapidity, if it is piled in certain parts of a room 

 so that it is injured by overcooling or by heating, or if the manage- 

 ment of the warehouse or treatment of the fruit in other respects 

 can be shown to have been faulty or negligent, the storage house has 

 failed to perform its proper function. 



The warehouse treatment is not supposed to insure the fruit 

 against the natural deterioration that may take place in cool tempera- 

 tures. The warehouseman holds the fruit in storage as a trustee for 

 the storer, and in that relation is bound to exercise only that degree 

 of care and diligence in the management of the building and its 

 contents that a man of ordinary care and prudence would exercise 

 under the circumstances in protecting the plant and the goods if they 

 were his private property. (Y. B. 1903.) 



Principles of Mechanical Refrigeration. In principle, mechan- 

 ical refrigeration is simple. To cool a substance to a definite tem- 

 perature and hold it there, it is necessary to absorb from it the sur- 

 plus heat which it contains and then to protect it against the absorp- 

 tion of additional heat from outside sources. As the expansion of 

 all substances, whether in solid, liquid, or gaseous form, is accom- 

 panied by the absorption of heat, it is only necessary that some mate- 

 rial in the act of expanding shall be in proximity to the object to be 

 chilled. Many different materials have been tried at different times 

 for this purpose. Several are still in practical use, but for the refriger- 

 ation of large chambers those most generally adopted at present are 

 certain gases, particularly anhydrous ammonia and carbon anhy- 

 dride. These are capable of being greatly reduced in volume by com- 

 pression by steam power into cylinders, even to liquid form, and can 

 then be safely shipped long distances to the points where they are 

 needed. When admitted to pipes in the building to be refrigerated 

 these gases expand and withdraw heat from the air of the surround- 

 ing chambers and from the articles stored therein. After traversing 

 a system of pipes the gas is relieved of its heat by being compressed 

 in a steam pump and passed through a condenser of pipe over which 

 cool water flows. The water, in fact, carries off the heat which the 

 gas has absorbed from the materials in storage, while the gas, reduced 

 to its liquid form, is available for repeating the process. In some 

 instances the expansion pipes are placed directly in the rooms to be 

 refrigerated, in which case the system is technically known as a 

 "direct-expansion" system. In others they are immersed in tanks 



