152 APPENDIX. 



Ponds is believed by Mr. Eamsbottom not to have 

 exceeded 300 ; and his opinion is confirmed by the 

 Commissioners present at the opening of the boxes, 

 and other observers. 



Immediately before commencing the operation 

 of depositing the Ova in the breeding troughs at 

 the Ponds, blocks of ice were placed in the small 

 stream which flows over them, which had the effect 

 of reducing the temperature of the water from 55° 

 to 44°. This was continued while the ice lasted, — 

 a period of two days, — and was found amply suffi- 

 cient to carry the Ova safely through the critical 

 stage of transition from the low temperature in 

 which they had previously existed to the higher 

 temperature of the Ponds to which they now be- 

 came exposed. AU danger, however, from this 

 source, if any existed, was effectually prevented by 

 a natural and considerable fall in the temperature 

 which took place in the water of the Plenty before 

 the supply of ice had become exhausted, and which 

 has since remained very uniform, not exceeding 

 49° nor falling below 39°. 



With a view to provide an additional guarantee 

 against total failure, a portion of the Ova were 

 subjected, in accordance with the advice of Mr. 

 Youl, to the process of hatching in an apparatus 

 entirely apart from the Ponds, and consisting of 

 two tubs filled with gravel and supplied with a 



