[13] PROPAGATION OF SCHOODIC SALMON IN 1879-'80. 745 



the night of the 5th the temperature of the air fell to 10° F., but since 

 the 7th it has stood constantly above the freezing point. 



November 16. — Have put into the old hatching-house 655,100 eggs, all 

 I think prudent to trust there this year, and shall fit up the troughs in 

 the new house for the remainder of the crop. 



November 17. — Set the reservoir tank, the head trough, and two deep 

 hatching-troughs in the new house, and at once placed eggs therein. 



November 19. — Examined lot 1 to-day, and find that the embryonic 

 disk now covers about one-third of the yelk. Out of 100 only 75 ap- 

 peared to be developing, indicating a loss of 25 per cent, from non- im- 

 pregnation. [This is afterwards determined to be very nearly correct, 

 but it was an exceptionally poor lot.] 



November 21. — The embryonic disk in lot 1 (14 days from impregna- 

 tion) now covers half of the yelk. In lot 2 (10 days from impregnation) 

 it is just beginning to expand. 



November 22. — To-day we admit to the old hatching-house a new sup- 

 ply of water, derived from the brook that flows past, which up to this 

 date has been shut out the present season, pending the preparation of a 

 pool for it to clarify itself in. This new supply increases the volume in 

 the hatching-house from 10^ gallons to 14f gallons per minute and lowers 

 its temperature from 46J° to 45° F. It will thus nearly double the 

 capacity of the house. The water from the new aqueduct is not yet 

 admitted. 



Grand Lake was frozen over last night as far up as Cedar Island (f 

 mile above the dam), but a scow was to-day forced through the ice. 



To-day we finish taking eggs and carry up 800 of our fish and liberate 

 them iu the lake from 1 to 2 miles distant. 



November 23. — By filling an empty trough and making a careful allow- 

 ance for leakage, I compute that each of the three troughs in the new 

 hatching-house is to-day using 17.7 gallons of water per minute, and 

 that three times as much is flowing to waste; that gives 53 gallons in 

 the troughs and 53 gallons waste, a total of 106 gallons per minute. 

 The size of the conduit is six inches square; its fall and length not accu- 

 rately ascertained, but the grade is near 1 in 1,000. This is while the 

 mills are shut down; with the mills running the head and the volume 

 in the hatching-house would be somewhat less. [Afterwards ascertained 

 to be 30 per cent, less.] The dams that control the water at the lower 

 ends of these troughs are leaky, and in case of a stoppage of "water 

 would leak dry in a short time, estimated at from 16 to 26 minutes. On 

 inquiring of Mr. Munson, I learn that he purposely left leaks at the bot- 

 tom of the dams to create a bottom draft, lest there should be too strong 

 a surface current at the expense of the lower trays of eggs. He and 

 Mr. Buck did that last year, having observed that the sediment settled 

 much more on the lower than the upper trays, indicating that the sur- 

 face current was the stronger. I approve this, and also approve putting 

 in cross-boards just above the dam, both at surface and bottom, to pre- 



