CULTURE OF THE SHAD. 153 



just named. All the facts connected with the incubation 

 are so interesting, and at the same time so new, that I 

 quote Mr. Lyman's observations almost entire : 



" Artificial Breeding of Shad. Early in last summer, 

 Seth Green offered to come, at his own expense, and try to 

 hatch the eggs of the shad at Holyoke, provided the New- 

 England Commissioners would furnish the necessary ap- 

 paratus. 



" Green began his experiments the first week in July. 

 He put up some hatching-troughs, like those used for 

 trout, in a brook which emptied into the river. Having 

 taken the ripe fish with a sweep-seine, he removed and 

 impregnated the ova in the way already described for 

 trout. These, to the number of some millions, he spread 

 in boxes ; but, to his great mortification, every one of them 

 spoiled. Nothing daunted, he examined the temperature 

 of the brook, and found, not only that it was 13 below 

 that of the river (62 to 75), but that it varied 12 from 

 night to day. This gave the clue to success. Taking a 

 rough box, he knocked the bottom and part of the ends 

 out, and replaced them by a wire gauze. In this box the 

 eggs were laid, and it was anchored near shore, exposed to 

 a gentle current that passed freely through the gauze, while 

 eels or fish were kept off. To his great joy, the minute 

 embryos were hatched at the end of sixty hours, and swam 

 about the box, like the larvae of mosquitoes in a cask of 

 stagnant water. Still, though the condition of success waa 

 found, the contrivance was still imperfect; for the eggs 

 were drifted by the current into the lower end of the box, 



