IMPERFECTLY KNOWN. 185 



seeing that, so lately as 1862, the Commissioners of the 

 Fishery Board employed men accustomed to use the 

 diving apparatus to examine the localities where the 

 herrings were supposed to deposit their spawn, and to 

 bring up portions of it for examination. Various places 

 in the Frith of Forth were examined without success, 

 but at last, east of the Isle of May, a considerable 

 quantity was found in twenty fathoms water, adhering 

 to coarse shelly sand, the deposit being about three- 

 fourths of an inch thick, and attached to a cake of the 

 rough shells and sand. Though the divers saw in the 

 vicinity of this spawn fishes like herring moving about, 

 they did not see them so distinctly as to enable them 

 positively to assert that they were herrings. The ova 

 thus obtained produced little fish, exhibited at a meet- 

 ing of the Koyal Physical Society, and some of them 

 lived in an aquarium about four weeks. Attempts also 

 were made to breed them by placing the ova in boxes 

 or cans in the sea, but unfortunately these were des- 

 troyed. There is thus only a strong probability that 

 the vivified ova were those of the herring. The defects 

 in this experiment are not thoroughly removed by Mr 

 Mitchell's account of the manner in which the herring 

 spawns. After describing the deposition of the ova on 

 stones, rocks, and sea-weeds, to which they firmly ad- 

 here, he thus proceeds : " The eyes are first observable 

 at least a small black speck is first seen in the egg. 

 Then the head appears ; and in fourteen days, or per- 

 haps three weeks, the young are seen in great abundance 

 near the shore, of a very small size. In six or seven 

 weeks more they are observed to be about three inches 

 in length, and move about in large shoals in winter and 

 spring on the various coasts, and in the rivers and bays 

 generally resorted to by the herring-shoals ; and it is 

 likely that they attain to full size and maturity in about 

 eighteen months." 



When we find, in the most recent work on the her- 

 ring, such indefinite phrases as those we have italicised ; 



