378 
BULLETIN OF THE UNITED STATES FISH COMMISSION. 
adds so much to the material to be frozen, but it also serves to hold the fish together 
in the frozen block. In some freezing-houses using tight-bottom pans the weight of 
tlie ice in the bottom of the Irozen block amounts to more than 5 per cent of the total 
weight. This, of course, increases the weight of the frozen fish when they are sold. 
An erroneous idea prevails, to some extent, that in using ice and salt for freezing, it is 
necessary to use tight-bottomed pans to exclude the brine. 
The fish are generally placed so as to make a neat and compact package entirely 
lining the pan, so that the cover will come in contact with the upper surface of the 
fish. It is desirable to have the backs of the fish at the sides of the pan and the 
heads at the ends, so as to protect the blocks in handling. It is also desirable, when 
the size of the fish so admits and a cover is used, that the bellies be placed upward, 
since that portion has greater tendency to decompose, and, as the cold passes down, 
this arrangement results in freezing the upper portion of the block first, and also in 
less compression of the soft portion of the fish by removing the weight theiefrom. 
This practice, however, is not by any means uniform. In case the fish have been 
split and eviscerated it is advisable to place them slanting on the sides, but with 
backs up, so as to permit the moisture to run from the stomach cavity, but that is 
not the general practice. Large fish are necessarily placed on their sides, the fish 
being curved, if necessary, so as to lie in the pan best. Some freezers place herring 
and other small fish on their sides two layers deep in the pans, while others i)lace a 
bottom layer of three transverse rows, the end rows with the heads to the edge of the 
pan, and a top layer of two transverse rows laid in the two depressions formed 
between the bottom rows. In case of pike and some other dry fish a small quantity 
of water is sprinkled over them, since they do not ordinarily retain sufficient moisture 
to hold together when frozen, as is the case with most other species. 
Formerly all pans were provided with covers, as described in Davis’s letters patent, 
and this is necessarily so at present, where ice and salt are used for freezing, the cover 
being required to separate the freezing materials from the fish. These covers are 
slightly larger than the pans, so as to slip on easily. The cover best adapted to a pan 
26 inches by 14 inches by 2 inches is 26J inches by 14J inches by If inches, with the 
sides slanting toward the base. But in some houses, where circulating brine or ammo- 
nia is the freezing medium, the covers are being discarded, resulting in a more rapid 
freezing of the fish, as the cold does not have to pass through the metallic cover. But 
in that case the top of the block of fish does not present so smooth an appearance 
as when the cover is used, for the latter presses the fish down somewhat and unites 
them more closely, making a firmer package. In order to make a compact block those 
houses not using covers usually place the small fish bellies down. Only a few freezing 
houses have discarded the use of the pan covers altogether, and in the more advanced 
freezers covers are used when the fish can be placed so as to come in contact with 
the cover, otherwise they are discarded. In many sharp freezers, including the one 
shown in the illustration opposite page 374, the greater portion of the pans have 
covers, while the others have none. 
As soon as the pans are filled and the covers fitted on they are placed in the sharp 
freezer. In houses where circulating ammonia or brine is used the sharp freezer con- 
sists of a series of coils of small circulating pipes, through which the freezing medium 
passes, on which the pans of fish are placed, the whole being inclosed in a room of 
suitable size provided with insulated walls and with doors. Where ice and salt are 
