EXPERIMENTAL WORK. 167 



the water, so I do not think the difference of two-fifths of a degree, 

 which would be equivalent to one day for half the period of 

 incubation, is possible for two consecutive trays. The average 

 temperature of the last 113 days has been 39787." 



This experiment was removed to Craigend House on the 5th 

 of May, and to a temporary rearing-place at Milnholme next day ; 

 two days afterwards it was mixed with Experiment 11. This 

 experiment showed that sea-trout eggs could be easily crossed 

 with burn-trout milt, and would hatch even under unfavourable 

 circumstances. 



Experiment 8. 



The idea of crossing Loch Leven and sea- trout occurred to ine 

 on 23d November, when I wrote to Mr. Burns Begg, Sir Graham 

 Montgomery's agent at Kinross, asking to get me a male and 

 female Loch Leven trout on the 27th November. Mr. Burns Begg 

 arrived at Sauchie at 4 P.M., with a large tub containing a pair of 

 splendid Loch Leven trout, about 3 Ibs. weight each, which had 

 been carried from Kinross without change of water. The snow 

 was deep, and drifted in places ; and soon after we left the house 

 at Sauchie, the keepers, carrying the tub across the fields to 

 Middlethird, stumbled, and upset the fish into the deep snow. 

 The excitement was immense, the men almost in tears at the 

 disaster ; fortunately it was not freezing, and the trout were con- 

 veyed the rest of the way in snow slush. They soon recovered in 

 one of the rearing-boxes in the hatching-house ; and I stripped 

 the female, and milted the eggs with a male sea-trout which I had 

 brought over from Touch some days previously. Total, 1296 ova. 



Experiment 9. 



I then spawned a sea-trout female, and milted the eggs with 

 the male Loch Leven, the converse of the preceding experiment. 

 Total, 912 ova. 



These two experiments commenced to hatch on March 19th,. 

 and on the following day I went over in the afternoon, and found 



