62 BULLETIN OF THE UNITED STATES FISH COMMISSION. 



rapid growth, indicating the adaptability of the waters of this bay to 

 this development, together, with the imaiense amount of shrimps, which 

 abound in this bay and furnish abundant food, have, I must acknowl- 

 edge, infused me with almost an enthusiasm to have this valuable fish 

 brought here in sufficient numbers to insure the breeding of them. I 

 have heard of some experiments having been made in breeding them 

 artificially. If that can be done, we might, of course, bring them out as 

 easily and in as great numbers as we now do shad, and my object in now 

 writing you is to ascertain the probability of such an effort being suc- 

 cessful. 



If it cannot be done our only course must be to enlarge upon and 

 extend the experiment of last year. The small fry can be obtained in 

 the fresh-water heads of the Navesink, the Raritan, the Passaic, the 

 Hackensack, and, in fact, all of those small rivers which flow from the 

 New Jersey coast into the Atlantic and the bays emptying into it. Will 

 you be so kind as to give the matter some thought and let us have the 

 benefit of it? The shad are a success, and we feel satisfied that so soon 

 as they shall have reached such numbers as to insure contact we shall 

 breed them in abundance. 



With much respect, I remain, yours truly, 



S. R. THROCKMORTON, 

 Chairman California Fish Commission. 



TSE SEIiF-PICKER. 



By FRANK N. CLARK. 



NORTHVILLE, MiCH., February 17, 1881. 



Dear Sir: Responding to your request for my opinion concerning 

 the operations of self-pickers, I submit the following: 



The name " Self-picker," as applied to any ova hatching apparatus 

 yet devised, claiming the ability within themselves to completely sepa- 

 rate the dead eggs from the living, is a misnomer. 



All self-pickers, so called, are emf>loyed in hatching eggs by what is 

 known as the bulk method, and the principle on which they are operated 

 is the same in each. This principle is based on the supposition that all 

 ova of confervoid growth, which are, for the most part, lighter than the 

 live eggs, can be driven or separated from the latter by a properly 

 adjusted current of water. But, when we consider that a small i)ercent- 

 age of the dead eggs possess no greater buoyancy than the live ones, 

 and consequently a current of water, strong enough to drive off all of 

 the former, must necessarily take with it some of the latter, the imi^ossi- 

 bility of devising any api)aratus that will be a comi)lete self-picker or 

 separator will be readily seen. Nevertlieless, I consider the method of 

 bringing forward the eggs in bulk far superior to any of the lia'ching- 

 box or tray systems now in use. It is practicable, however, to develop 



