70 AMERICAN FISHKRIKS S(K:1ETY. 



are then removed to be packed in the storas^e or preserving box. 

 If desired, tlie fish may be coated with ice by immersion in iced 

 water ; they may then be wrapped in cloth and a second coat- 

 ing of ice applied, or they may be coated with gimi-arabic, 

 gutta-percha, or other material, to exclude the air and to pre- 

 vent the juices from escaping by evaporation. The storage box 

 is a double one, the inner one without a cover ; the space be- 

 tween the sides and bottoms of tlie two being filled with char- 

 coal or other non-conductor. Metallic tubes for the freezing 

 mixture pass through the cover of the outer box and through 

 the bottoms of both boxes, connecting with a small pipe to 

 carry off the brine. The combined area of the tubes is required 

 to be about one-fifth of the area of the inner box, in order to 

 keep the temperature below the freezing-point. 



Numerous and complex methods of freezing fish have been 

 devised since Mr. Piper obtained his patent, but the simplest 

 methcjds are perhaps as effective, and are surely more econom- 

 ical than the expensive machinery sometimes used. 



In 1869 Mr. William Davis, of Detroit, patented a freezing pan 

 for fish, which he describes as a thin sheet metal pan or box in 

 two sections or parts, one made to slide over the other, the ob- 

 ject being to place the fish or meat in one part of the box, and 

 to slide the cover on to or in contact with the freezing mixture. 

 The pans are packed on top of one another in a freezing box 

 with iced salt over and around them. By this method from thirtv 

 to fifty minutes is said to be sufficient to complete the freezing, 

 when tiie fish may be taken from the pans and stored in a keep- 

 ing chamber, where the temperature is C(jnstant at six to ten 

 degrees below the freezing point. 



In 1869, Mr. Davis also patented a preserving chamber, which 

 may be a room, box or chamber of any desired form. It has 

 two walls with the intervening space filled with a non-conduct- 

 ing material. Within this are metal walls of less length than 

 the outside walls, so that between the two a freezing mixture 

 may be placed. Entrance is obtained through the top or side 

 by closely fitting doors or hatches. Other methods of freezing 

 fish have been patented, such as making a series of seven cir- 

 cular pans of a size to fit in a barrel, and of putting the fish in 



