272 SEASON 1878-79. 



7 the following morning only 5 survived ; they were of all sizes, 

 including one of the smallest and one of the biggest, measur- 

 ing 2^ inches and 6 inches respectively. I weighed the remaining 

 95, and found them to be 23 oz., therefore the 100 yearlings would 

 weigh almost exactly 1| Ib. The 6 largest weighed 4 oz., and 

 were all over 5^ inches long; the 8 smallest weighed 1 oz., and 

 were from 2^ to 3 inches long. 



The temperature of the air at the commencement of the experi- 

 ment was 40 F., and fell below freezing during the night. The 

 water was not aerated artificially. According to the foregoing 

 formula, 7 Ibs. weight ought to have survived for the period of 

 time occupied, according to the hour-gallon formula. It is possible 

 the formula does not hold good for very small trout, say under 

 4 inches in length, but the absence of any aeration of the water, and 

 the formation of a thin skin of ice on the surface in the morning, 

 are sufficient to account for the unsatisfactory results. At 11 A.M. 



1 repeat the experiment, placing 100 yearling trout from the centre 

 20-feet pond (No. 2) into a conical tank, with 12 gallons of water ; at 

 7 P.M. that is, after eight hours they were all lively. The tempera- 

 ture of the water during the experiment was about 40 F. At 1 1.20 

 A.M. I placed 7 four-year-old Lochleven trout, weighing 12 pounds, 

 and each 'fish between 15 inches and 16 inches in length, into a 

 conical tank with 12 gallons of water, temperature 40 F., the 

 same as in preceding experiment. At 2 P.M. one fish showed symp- 

 toms of distress. I removed it, and then aerated the water with a 

 syringe. At 3 P.M. I aerated the water by lifting some out 

 with a jug and pouring it back. At 5.30 P.M. I again aerated the 

 water with a jug ; the fish were then much more lively than at 



2 P.M. At 7 P.M. all the fish showed symptoms of distress, two 

 being very sick, but on aerating the water with the jug, they all 

 'recovered. I then returned the fish into the centre 130-feet pond 

 (No. 7). 10^ gallons of water would have been sufficient, accord- 

 ing to the hour-gallon formula, and with a little earlier and more 

 frequent aeration, it certainly appears it would have been ample. 



tot 

 By the formula g= here, one fish weighing 1^ Ib. was removed 



