610 U. S. BUREAU OF FISHERIES 



The can is laid upon its side on a working table. The frame, with 

 partitions in place, is laid on a board with the end at the mouth of 

 the can, the board raising' the frame at such an elevation that it 

 will slide directly into the can without disturbing the fillets. The 

 fillets are packed and arranged in the spaces between the partitions 

 of the frame, and the latter is slid into the can. The can is then up- 

 ended and let down into the brine tank, the top protruding some- 

 what above the brine level, as in Petersen's system. The cans, being 

 handled singly, are not heavy enough to require a mechanical hoist 

 but are lifted by hand. When the fillets are frozen, the cans are 

 withdrawn and dipped a moment in water, whereupon the frame is 

 pulled from the can and the frozen bricks of fillets are released and 

 packed. 



Another form of Birdseye's freezing mold is a flat can opening 

 at a large side instead of at the end. A side lid is arranged to be 

 fastened on by means of thumb nuts and a gasket to prevent en- 

 trance of the brine. This mold is immersed bodily in the brine. 



This method of Birdseye's was designed to meet a more specialized 

 business than were most of the other methods hitherto described; 

 namely, the dressing of fish and preparing fillets for cooking and 

 freezing, all at or near the point of production of the fish, for ship- 

 ment to consumers. The frozen bricks were packed in insulated con- 

 tainers and, containing their own refrigeration, went forward with- 

 out ice as dry packages. Birdseye at first used a double-wall box 

 made of corrugated strawboard, with dried eelgrass between the 

 walls. He later adopted the simpler and less expensive practice of 

 insulating ordinary corrugated strawboard boxes with two or more 

 extra thicknesses of the same material cut in panels to fit the sides, 

 top, and bottom of the box. 



If the fish contain 75 per cent of water, all frozen, the package 

 contains the equivalent of 60 or 70 per cent of its net weight in the 

 form of ice for refrigeration. Ordinary shipments of fresh fish on ice 

 usually have the same weight of ice as fish for refrigeration. Thus 

 the contents of a box of 100 pounds net weight of fish would, 

 together with the ice, weigh 200 pounds, only 50 per cent of the 

 contents being fish. In the frozen bricks a shipment of 100 pounds 

 of fish without ice would contain the equivalent in refrigeration of 

 60 or 75 pounds of ice, total weight of contents 100 pounds — an obvious 

 advantage. Furthermore, the reserve refrigeration, being contained 

 in rather than around the fish, is protected from loss by the insulating 

 effect of the fish itself, for we have already seen that the thawed layer 

 of fish around a frozen core during defrosting is a relatively poor 

 conductor of heat. The economic soundness of this method of pre- 

 paring fish for transportation is further substantiated by the removal 

 of all nonedible parts of the fish and the use of a much lighter 

 shipping package. 



While Birdseye's business establishment was not a financial success, 

 the methods he introduced appear to be economically sound and his 

 freezing apparatus inexpensive and practical. As will be seen later, 

 the fundamental ideas have been improved by others and are being 

 applied in practice. 



A simple experimental box, operating on Taylor's brine-spray 

 principle, was put into practice by The Atlantic Coast Fisheries Co. 



