10 U. S. BUREAU OF FISHERIES. 



suitable) the eggs forming the pack will soon die and form a mass in 

 the jar. 



In a few days, varying with the water temperature, the unimpreg- 

 nated and other dead eggs begin to fungus ; that is, a fungous growth 

 develops upon them and they rise to the top of the egg mass. Such 

 eggs must be removed with a siphon immediately, and if live ones 

 are among them they should be set up in what are termed hospital 

 jars, where the dead eggs and the live ones can be more readily sepa- 

 rated. The dead eggs are drawn off every day to prevent them from 

 becoming loaded with silt from the water and sinking into the mass 

 of live ones, from which it is difficult to separate them. 



A long-distance siphon is used for removing dead eggs from the 

 jars, saving much labor. In its construction the short end of an 

 ordinary siphon, consisting of a thin |-inch brass tube a foot long 

 bent into the form of a gooseneck, is attached to a piece of common 

 rubber tubing 3 or 4 feet long and f inch in diameter inside. This 

 is connected with a rubber tube of the same size and sufficiently long 

 to reach the entire row of jars in the battery. Hose connections are 

 made by the use of a thin brass nipple of the same interior diameter 

 as the piece of rubber tube to which it is joined. The other end of 

 the long tube is connected to and through the center of a wooden 

 float some 12 inches in diameter and 1 or 2 inches thick by means of 

 a piece of brass tubing. The tube is bent to a quarter circle to 

 prevent the rubber from kinking, and the float is set in a tub. When 

 it is desired to siphon eggs into the jars, a short siphon is placed in 

 the supply trough and started and is then connected with a long 

 siphon. t\^ien the tub becomes filled with water, it runs over the 

 rim and into the waste ditch, the eggs settling to the bottom. By 

 means of this siphon an entire battery can be operated without mov- 

 ing the tub. It is necessary, however, to exercise care in siphoning 

 eggs from the jars on the top row, as the suction becomes very 

 strong and is apt to draw off the good eggs. The suction may be 

 reduced by gently pinching the rubber tube. 



For convenience and economy of space and water the hatching 

 jars are arranged in tiers, constituting what is known as a hattery. 

 The structure of a battery, with its system of supply troughs, jars, 

 and other attachments, may be understood by reference to Figures 



5 and 31. 



The troughs of the battery are usually constructed of white pine 

 or cypress 1| inches thick. If it is necessary to make the troughs 

 longer than the usual cuts of lumber, the joints should be squarely 

 butted, and these and all other joints in the troughs should be put 

 together with white lead. At the splice a patch is placed on the 

 inside of each trough and screwed to the two ends, white lead being 

 used freely underneath. As a further strengthening measure a 

 cross piece 5 inches high is placed inside. The ends of the troughs 

 are rabbeted in place and the side pieces nailed to the bottom. At 

 the end of each trough in the bottom is a 1^-inch hole, supplied 

 with a plug, for use in cleaning the troughs. At the alternate end of 

 each trough, commencing at the top, is a saw cut 1| inches deep and 



6 inches wide, into which is fitted a galvanized iron or tin overflow 

 spout to conduct surplus water to the next trough below. The 

 lengths of the troughs vary according to the size of the battery. 

 Their inside dimensions are 10| inches deep and 8 inches wide. 



