ON THE TRANSPORTATION OF SHAD. 365 



temperature being the same. In this jar the one-eighth supply of mix- 

 ture every three hours had a more slowly-increasing proportion of sea- 

 water. The first supply at 9 p. m., August 15, was \ gill of sea-water 

 and 15£ gills of fresh water. At 12, midnight, the mixture was one gill 

 of sea-water and 15 gills of fresh water, and at 3 a. m. of the 16th it 

 was 1\ gills sea-water and 144 gills fresh water. At this rate of increase 

 the supplies would become all sea- water after 93 hours. 



In this much more gradual increase of sea- water the young shad 

 began to show weakness on the 19th, the contents of the jar having 

 reached a per centum of about 75 sea- water. At 9 p.m. of that date, three 

 hours after the first supply of all sea- water, they were observed to be 

 dying. At this time the sea- water was 81 per centum of the whole con- 

 tents. At 6 a. m. of the 20th, there were considered to be one-half of 

 them dead, and on the 22d, at 9 a. m., the last of them died. The jar 

 contained a solution of sea-water, 98.8 per centum sea-water and 1.2 

 fresh water. 



The temperature had varied from C8° to 78°. The latter, occurring 

 on the 20th, no doubt had some effect in reducing their vigor. They 

 were, at the time the last of ttiem succumbed, 189 hours from the egg, 

 and had been in the jar 156 hours. 



The iucreasing proportion of sea-water in the supplies to No. 3 was at 

 the same rate as No. 2. It was continued until the mixture became 

 half sea- water and half fresh, and the supplies from that time, the 

 17th at 6 p. m., forward, were in this proportion. The fish began dying 

 at 9 a. m. of the 22d, the per centum of sea- water being 49.80, and at 3 

 a. m. of the 23d all were dead, the last ones being about 207 hours old, 

 and having been in the jar 174 hours. The water had become 49.93 sea- 

 water. 



Jar No. 4 proved the most enduring of any of the experiments with 

 sea-water. Beginning approximately at the same time, and with tem- 

 perature the same as the others, in this jar the addition of sea- water 

 to the supplies was at the same rate as in that of Nos. 2 and 3. The addi- 

 tion of £ gill of sea-water at each interval of three hours to the mixture, 

 with a corresponding decrease of fresh water, made the proportions of 

 fresh and salt water in the supply, at the end of 30 hours, about one- 

 third of the latter and two-thirds of the former. This proportion was 

 thereafter retained. The fish began dying at 6 a. m. of the 23d, when 

 the per centum of sea-water was 34.35. At 6 p. m. of the 23d about 

 seven-eighths were dead, the water having attained a per centum of 

 34.30 sea-water. At 7 p. m. of the 25th the last one died having at- 

 tained the age of 271 hours, and having been in the mixture about 238 

 hours. The sea- water had reached the percentage of 34.37. 



These were all the experiments made with proportions of sea-water. 

 Others were made with pure sea- water and with surface-water from the 

 bay in which the fresh-water drainage had more or less diluted the salt. 



A jar was filled with sea-water several times and a quantity of shad 

 placed in it. They invariably died within three hours. 



