88 NATURAL HISTORY SOCIETY OF DUBLIN. 



in sets of three steps, by which means the water from the niters flow s 

 through all the boxes, as indicated by the arrows in the south tier of 

 boxes (see fig. 1) ; an open zinc lip carrying the water from one box 

 to another. Each box is covered by a slip of board, and the whole 

 hatching apparatus is enclosed by a palisade, to protect it from being 

 disturbed. 



On the Screeb Eiver the propagation is conducted by the well- 

 known piscatorian, Mr. Ramsbottom. It is on quite a different system 

 from that at either Gal way or Inver, as the eggs are placed in canals cut 

 alongside one of the waterfalls in the river, and an equipollent supply 

 of water is procured by means of a regulation pipe from the river. 

 The canals are about four feet wide, and twenty- five feet deep; 

 and, as they are on an incline, the depth of the water is regu- 

 lated by small dams built across them at about e^ery five yards. The 

 bottoms of the canals are covered with broken stones (about two inches 

 square) ; on them the eggs are placed, and over the latter are flattish 

 stones, which average about five inches square. 



As more able observers have described the process of collecting the 

 ova, and placing them in the boxes, I shall not waste the time of the 

 Society in describing them, but shall suggest what appear to be the faults 

 at the different places that I have mentioned. 



At Gal way and Inver the water runs direct from the filters on to the 

 eggs. This seems to be a bad arrangement, as at both these places the 

 upper boxes become filled with sediment, which causes a great destruc- 

 tion among the eggs, as the addled eggs that are covered with sediment 

 cannot be seen and picked out ; therefore they contaminate all those in 

 their vicinity. I would therefore suggest that between the filters and 

 hatching boxes there ought to be a long, narrow, vacant box, in which 

 the sediment could settle. At Galway the boxes were connected by 

 small leaden pipes. These, during severe frosts, were frozen up, and a 

 man had to be constantly employed boring them out ; a thin coating of 

 carbonate of lead also formed in the pipes, which must have been pre- 

 judicial to the eggs. These faults were remedied at Inver, as zinc was 

 used in place of lead, and open lips in place of pipes. At Inver, imme- 

 diately after the boxes were placed, a rat found its way in through the 

 openings under the lips, and destroyed some of the eggs ; but this was 

 remedied by covering the opes with perforated zinc. The Galway boxes 

 were under cover, and by that means the temperature could be regu- 

 lated to a certain extent; at Inver they were not, and the sudden 

 changes in the weather this last winter and spring caused many of the 

 eggs to addle. The plan acted on at the Screeb Eiver does not to me ap- 

 pear as good as hatching boxes ; for the number of young fish that come 

 out cannot be known, also the addled eggs cannot be extracted from 

 among the others. Therefore, if one becomes bad, all those in contact 

 with it will also be destroyed ; and I have counted as many as a dozen 

 white eggs strung together. Besides, the little fish must be very liable 

 to fall victims to water beetles, and such other insects that prey on 

 Salmon fry. The eggs would also seem to be open to such poachers, for 



