PRESERVATION OF FISHING PRODUCTS FOR FOOD. 
515 
From the filler the can jiasses to a man who places it on a swiftly revolving plate having a 
closely fitting cap, and a small ljut strong stream of water is made to play against the revolving can, 
removing all grease and dirt. A small scrap of flat tin is put on top of its contents, and the prepared 
top is fitted on. In order to keei> the top in place pending soldering, the can next goes to a man who 
places it on a revolving plate, while, by means of a lever operated with his foot, the top jilece is forced 
down and securely held at the same time the edges are being smoothly crimped. The sealing of the 
top is ingeniously accomplished. A brick furnace has on its top a long V-shaped trough that is kept 
filled with molten solder. At the upper end of the solder trough and a few inches higher is a similar 
one iilled with muriatic acid. From the crimping machine the cans drop in an almost continuous 
stream into the trough with acid. A heavy endless chain passes along just over the troughs, and by 
the friction from the chain the cans are carried on first through the acid, which touches only the outer 
edge of the top of the can and prepares it to receive the solder through which it next passes. The 
top of each can has a small hole punched in it to permit the escape of air as the can becomes heated 
in its passage through the trough of molten solder. Hero may be noticed the utility of the small 
piece of tin before mentioned as being put in the can, without Avhich the hole is liable to bo clogged 
up with fish, and, the vent being closed, the cans are liable to be badly strained, made leaky, and 
have the entire top blown out. 
The endless chain, having rolled the cans through the solder, drops them on an inclined plane 
some 30 or 40 feet in length. Shortly before reaching the bottom of this incline the cans are met with 
a shower bath of cold water from perforated pipes alongside of the incline. The bath is simplj^ to 
cool them so that they can be instantly handled. The cans are at once placed on iron trays, known 
as coolers; they consist of an iron frame 35 inches square, 3 inches deep, with slatted iron bottom. 
One cooler holds 86 one-pound flat cans, or 160 one-pound tall cans. The small venthole on top of 
the can is next sealed. The cooler filled with cans is then attached to an overhead rail track and 
transferred to a large wooden vat filled with water, having a temperature of 212^^ F. The cans remain 
in this bath only a few moments, which is ample time to test them for leaks. If a can is not perfectly 
air-tight, this fact is at once made evident by small air bubbles rising froin the can while in the bath, 
and it is at once removed for repairs, another can being substituted. When the test is comxileted, the 
cooler is placed on a small iron-framed car having a capacity of 8 coolers, one on top of another. 
The cans are now ready for the cooking of the salmon in large retorts. 
Retorts are made of wood or iron, but are usually of boiler iron, have a round shai^e, and are 
about 13 feet long and 5 feet in diameter. A steam pipe extends along near the bottom. This is per- 
for.ated for the escape of steam, which passes through a small amount of water with which the pipe is 
covered. On an iron track just over the pipes the loaded cars are run. Retorts usually have an open- 
ing or door at only one end, but in the cannery now being described there was an opening at each end 
and two retorts were used, the few feet separating them being connected by a track by which cars of 
coolers having passed through the first retort can jiass on into the second. Each retort has a capacity 
oft cars, or 3,200 one-pound tall cans or 2,9.52 one-pound flat cans. Cans of salmon remain in the first 
retort under a steam temxierature of 230'^ for one hour. They are then run out, vented, and at once 
resealed. As the top of each can is perforated with a small, sharp-pointed iron, the heated air or 
steam is expelled, and before its place can be taken with cold air the vent is closed by a drop of solder, 
and the can may be said to be free of air and air-tight. The cans are now ready for another cooking 
in the second retort. Here the temperature is 240°, in w^hich one-pound tall cans remain 1 hour and 
flat cans 1;^ hours. Retorts are under a steam pressure of 7 to 10 pounds to the square inch. 
On removing the cans from the retorts they have a stream of cold water thrown on them, by 
which they are cooled and cleaned. They are now' finally tested for leaks or inii)erfoctious by tapping 
each can on the top with a small piece of iron, an experienced ear quickly detecting by sound any 
imperfection. Imperfect cans are replaced by others, and the cans pass on to lie lacquered, labeled, 
and packed in boxes, each holding 48 onc-ponud cans or 24 two-]iound cans. They are then ready for 
a distribution that reaches almost every jiortiou of the civilized globe. 
The cannery at which these notes w'ere taken was provided wdth electric lights and ample steam 
power; the rooms were well ventilated and lighted ; its walls -were white with paint or whitewash. 
It is located on the Columbia River with the Cascade Range of mountains tow'ering from 1,500 to 2,500 
feet just at its back. From these mountains the icy-cold and very pure water used at the cannery is 
brought. 
