PRESERVATION OF FISHERY PRODUCTS FOR FOOD. 
373 
As the trade developed, the size of the storage rooms was iucreased and improve- 
ments were adopted in the arrangement and form of the iee-and-salt receptacles and 
in the method of handling the fish. But the freezing with pans immersed in ice and 
salt, as in the Davis process, and the subsequent storing of them in the manner used 
by Piper, continued without any great modification until the introduction of ammonia 
freezers into the fishery trade in 1892, At that time ice-aud-salt freezers and storage 
rooms existed at nearly all the hshiug j)orts on the Great Lakes; eight or ten small 
ones were in New York City, and several were in use on the New England coast. 
Some of those on the Great Lakes were very large, with storage capacity of 700 or 800 
tons or more, and the aggregate storage capacity of all in the country approximated 
8,000 tons. Ammonia cold-storage houses had been established at various places 
along the coast and in the interior during the ten or fifteen years preceding, and in 
these some frozen fish had been stored. But the first ammonia establishment for 
freezing fish exclusively was established at Sandusky, Ohio, in 1892, The method of 
freezing differs from the former process in that the pans of fish are placed on and 
between tiers of pipes carrying cold brine or ammonia instead of being immersed in 
ice and salt. In the storage rooms less difference exists, coils of brine pipes taking 
the place of the ice aud-salt receptacles, the blocks of fish being removed from the 
pans and stored as in the older process, 
DESCRIPTION OF ICE-AND-SALT FREEZERS. 
The outfit of an ice-and-salt freezer consists jirincipally of temporary stalls or bins 
where the fish are frozen, and insulated rooms where the frozen fish are stored at a low 
temperature. In addition to these there are ice-houses, salt-bins, freezing-pans, and 
the various implements for the convenient prosecution of the business. The freezing 
bins are usually temporary structures withiu the fish-house, and are generally without 
insulation. The wall of the fish-house may form the back, while loose boards are fitted 
in to form the sides and front as the bin is filled, in the manner hereafter described. 
A better way is to build the bins with sides and back 4 or 5 inches thick, filled with 
some nonconductor, with double or matched floor and with movable front boards. 
The storage rooms are commouly arranged in a series side by side and separated 
from each other by well-insulated partitions, the capacity of the rooms ranging from 
25 to 200 tons each. The outer walls of these rooms, as well as the floors and ceilings, 
are well insulated, made usually of heavy matched boards, with interior packing of 
some nonconductor of heat. Among the latter may be mentioned plauing-mill shavings, 
sawdust, pulverized charcoal, chopped straw, slagwool, etc. Most of the walls are 10 or 
18 inches thick, filled with planing-mill shavings or sawdust, and in some freezers the 
damaging effect of rats is obviated by placing linings of cement between the shavings 
and the board walls. Most of these loose materials have their economic drawbacks, 
chiefly because of their strong hygroscopic tendency, the material losing its insulating- 
power and decaying, this decay also attacking the wood of the walls. Because of this, 
many of the storage rooms recently constructed are insulated by having the walls 
made up of a combination of mineral wool, insulating paper, air spaces, and inch boards. 
The sides, and in some cases the ends, of the room are lined with the ice-and-salt 
receivers, consisting of galvanized sheet-iron tanks, 8 or 10 inches wide at the top, 
narrowing to 3 or 4 inches at the bottom, and placed about 4 inches from the wall in 
order to expose their entire surface to the air in the room. These tanks open at the 
