804 



UNITED STATES, FISH-CULTURE IN THE. 



continual motion could be kept up independ- 

 ently of the action of the current. The plung- 

 ing buckets, invented by Mr. T. B. Ferguson, 

 which were operated by steam machinery, were 

 at one time used instead of the Green box for 

 hatching shad-eggs in still water; but they 

 were soon replaced by less expensive appa- 

 ratus. 



At present, it is customary among fish-cult- 

 urists to classify hatching-apparatus with refer- 

 ence to the kind of eggs for which it is intended 

 to be used. Four types of eggs are recognized : 



applied from an engine by means of a horizon- 

 tal arm fixed to its axis, and is kept constantly 

 turning backward and forward through an arc 

 of ninety degrees, thus creating a free circula- 

 tion of water which gives a motion to the eggs. 

 For hatching semi-buoyant eggs, such as those 

 of the shad, the Green hatching-box was former- 

 ly the only one successfully used in the United 

 States. Several modifications of it have been 

 made, the most prominent among them being 

 that invented by Mr. Brackett, and first used 

 in 1873. " In this the box floats horizontally, 

 but has the up-stream 

 end beveled, and the 

 water, striking against 

 it, produces an eddy 

 under the box, which 

 causes a gentle agita- 

 tion of the eggs." An- 

 other substitute was 

 suggested by Mr. E. 

 M. S til well, Fish Com- 

 missioner of Maine, 

 and Mr. Charles G. 

 Atkins, now in charge 

 of the United States 

 salmon - hatchery at 



WHITE-FISH (Coregvnus clupdformis).* Bucksport, Me. None 



of the modifications, 



however, succeeded so well as the Green box. 

 The form of apparatus now used by the United 

 States Commission and by many of the State 

 Commissions, is the hatching-jar devised by 

 Col. Marshall McDonald, of the United States 

 Fish Commission. This is " a glass jar with 

 metal cap containing two circular openings. 

 Through one of these, in the center, a glass 

 tube for the introduction of water passes to 

 within a short distance of the bottom of the 

 jar. The other, near one side, contains a 

 shorter glass tube, which serves as an outflow- 

 pipe. The McDonald jar is successfully em- 



1. Buoyant eggs, such as those of the cod and 

 the mackerel, which will float in water; 2. 

 Semi-buoyant eggs, such as those of the shad 

 aiidthe white-fish; 3. Heavy eggs, such as those 

 of the trout and the salmon ; and, 4. Adhesive 

 eggs, like those of the perch, the smelt, and the 

 sea-herring, which adhere to surfaces with 

 which they may come in contact. No form of 

 apparatus has yet been devised which will sat- 

 isfactorily hatch floating eggs. Some of the 

 first experiments in the hatching of cod-eggs 

 were made by Prof. G. O. Sars, of Christiania, 

 Norway. At the International Fisheries Exhi- 

 bition, in London, 1883, was shown a vase, in- 

 vented by Mr. Oldham Chambers, for hatching 

 buoyant eggs. In this the supply-pipes are 

 perpendicular and perforated at an angle of 

 forty -five degrees, and with an upward tend-' 

 ency, thus assisting the floating of the ova. 

 A form of apparatus used with moderate suc- 

 cess by the United States Fish Commission at 

 Gloucester, Mass., in 1878, was devised by Capt. 

 H. C. Chester, for eggs of the cod, and this 

 was the first to accomplish the purpose desired. 

 The hatcher known as " Chester's Semi-rotat- 

 ing Hatcher," is a cylindrical can, with five 

 rectangular openings of wire-cloth on the side 

 and a bottom of like material, to allow a cir- 

 culation of water, and to prevent the loss of 

 eggs or the escape of newly-hatched fish. Be- 

 neath the bottom are four strips of tin, radiat- 

 ing from the center and placed at such an an 



^ 



MCDONALD'S JAB. 



ployed in the hatching of various species of 



gle that the rotation of the cylinder upon a heavy eggs," as well as for semi-buoyant ova. 

 vertical axis forces the water against them and " The water in entering is thrown against the 

 up through the bottom. Several of these cans bottom with considerable force, and is deflect- 

 are placed in a trough of running sea-water, ed upward around the sides of the jar. The 

 Each can turns on a pivot, the power being eggs, which tend to settle to the bottom, are 



