364 REPORT OF COMMISSIONER OF FISH AND FISHERIES. 



varying treatment to the series of jars, but as it was always begun 

 with No. 1, and carried through with the same order, the interval for each 

 jar was always the same, and in recording, the hours of 9, 12, 3, and 6 were 

 used for convenience sake, though strictly they would apply only to 

 No. 1. 



The purpose of. the tests with 1, 2, 3, and 4 was to try if gradually 

 increasing proportions of sea- water would enable the young shad to be- 

 come accustomed in time to supplies of pure or nearly pure sea- water 

 without diminishing their vigor and vitality. 



No. 1, at 9 p. m. August 15, had 128 gills of fresh water at a tempera- 

 ture of 71° Fahrenheit. Two quarts of the water were drawn off, and 

 this was replaced by two quarts of a mixture, 15 gills of which were fresh 

 water and 1 gill was sea-water. Three hours later, at 12 midnight, 

 two quarts were again removed from jar No. 1 and two quarts of a mix- 

 ture of 14 gills fresh water and 2 gills sea- water poured in. At 3 a. m. 

 of the 16th two quarts were again removed and a mixture supplied of 

 13 gills of fresh water and 3 of sea- water. 



This supply of a mixture amounting to one-eighth the contents of the 

 jar, with a continually increasing proportion of sea-water, was afforded 

 every three hours. At the end of 45 hours the two quarts of supply, 

 having the sea-water proportion increased one gill each time, would be 

 all sea-water. After the 45 hours, at 6 p. in. on the 17th, or the fifteenth 

 supply of water to the jar, two quarts of sea-water were afforded every 

 3 hours, a like quantity being at the same time removed. At this 

 rate the water upon the fish at the end of 24 hours, or 9 p. in. of the 

 16th, would be about 25.6 per centum sea-water. 



At the end of 48 hours, or 9 p. m. of the 17th, the jar would contain 

 a mixture with 66.2 per centum sea-water. At the end of 72 hours, or 

 9 p. m. the 18th, the mixture would become 88i per centum sea-water. 



The temperature remained very even until noon of the 17th, when 

 it fell to about 67°, 3° less than at 9 a. m. The 18th, at 6 p. m., it had 

 again risen 4°. 



The shad seemed to retain vigor and health until the 18th. They 

 showed weakness in the morning, the per centum of sea-water having 

 reached 80J, and at 6 p. m. they were all lying on the bottom of the jar, 

 the per centum of sea-water being 86.8. A few of these were taken out 

 and put into a glass jar which contained a mixture of one quart fresh 

 water and one quart sea- water ; in this the most of them revived and 

 lived from 6 p. m. August 18 to 6 p. m. August 22 — 96 hours longer than 

 those left in the jar. 



In the jar No. 1 they were soon after all dead. They were about 102 

 hours old, and had been kept about 17 hours in the hatching boxes, about 

 16 hours in the cans, and 69 hours in the jars with the sea-water mixtures. 

 Those revived in the glass jar were 19S hours or eight and one-fourth 

 days from the egg at the time of death. 



The treatment of No. 2 began at near the same hour as No. 1, the 



