528 NATURAL HISTORY OF AQUATIC ANIMALS. 



In 1873, a device to accomplish like results was made by Mr. N. W. Clark, of Clarkstoii, 

 Micnigan, and patented in 1874. 1 



This arrangement employed the troughs, but divided them into compartments by means of 

 water-tight partitions or bulkheads; into each compartment a box containing a series of trays 

 filled with eggs is placed and covered with a pan of perforated tiu, upon which the water falls 

 and descends through the perforations upon the screens and eggs beneath, passing through all 

 and escaping at the bottom, afterward flowing over the partition upon the cover of the next box, 

 and so throughout the series of compartments until it escapes through the waste- way at the end 

 of the trough. By this arrangement a very small quantity of water is required for a very large 

 number of eggs, and all the advantages of handling and removal of sediment and considerable 

 economy of space are afforded. 



Another combination of the trough and tray methods is in use in California, devised by Mr. 

 John Williamson, of the California Acclimatizing Society. This is very similar to the one just 

 described, except that the flow of water through the screens and eggs is from below instead of 

 from the top. This model was not the result of work in white-fish hatching, as in the case with 

 the two first named. 



An experiment was made by Mr. N. W. Clark in the hatching of white-fish eggs, which were 

 laid in single layers of woolen cloth stretched on very thin frames of wood, packed in a box 

 imbedded in sphagnum moss within a refrigerator, and the whole kept at a temperature a little 

 above the freezing point by ice. The eggs are left entirely undisturbed after they are first 

 arranged, and the only care on the part of the attendant is to keep the temperature above 

 the freezing point. The presence of dead eggs does not seem to contaminate the living 

 ones in this condition, and very little confervoid growth appears. A quantity of eggs carried 

 forward in this manner through the winter appeared to be in excellent condition, development 

 progressing slowly, and a few, taken from the cloths and placed in spring water, hatched out 

 within a short time as well-developed embryos. If this method, after full and thorough trial, 

 should prove successful, it would make the work of hatching a matter of neither effort, care, nor 

 expense. It has been a matter of too short experience and of experiment on too small a scale to 

 warrant its positive success. 



An improved case for the carriage of eggs long distances by railroad is another device 

 lerfected by Mr. N. W. Clark in 1872. It is a modification of the ordinary case containing 

 circular cups, the cups being square, and in this form economizing space very much. The cups of 

 tinned iron, about four inches square and two inches high, rest in trays, with low partitions forming 

 low compartments that retain the bottom of each cup and hold it solidly in place. The trays are 

 set within a square tin box, in which they fit with moderate tightness, and are placed, when 

 containing the cups, eight or ten in the box, one above the other; this box is set within another 

 box of tin large enough to leave an open space on all sides, to be filled with sawdust; a tube is 

 inserted through the bottom of the inner box, piercing the bottom of the outer one, so as to permit 

 communication with the air on the outside. The whole is then placed for protection within a strong 

 wooden box, in the bottom of which is a frame resting upon stiff springs which relieve the eggs 

 from heavy jarring; rubber or cloth bumpers on the sides of the box prevent lateral swaying and 

 jolting. A cover is fitted to the inner box, which may then be covered with sawdust to the level 

 of the higher outer one, when the cover of this is to be shut down. The outside wooden box is 



1 Report U. S. Fish Commission, part vi, p. 546. 



