GOLD CARP. 317 



temperature of the water can be maintained at an elevation 

 above the ordinary mean. 



" It is Avell known that in manufacturing districts, where 

 there is an inadequate supply of cold water for the conden- 

 sation of the steam employed in the engines, recourse is 

 had to what are called engine-dams or ponds, into which 

 the water from the steam-engine is thrown for the purpose 

 of being cooled : in these dams, the average temperature 

 of which is about eighty degrees, it is common to keep 

 Gold-fish ; and it is a notorious fact, that they multiply 

 in these situations much more rapidly than in ponds of 

 lower temperature, exposed to the variations of the climate. 

 Three pair of this species were put into one of these dams, 

 Avhere they increased so rapidly, that at the end of three 

 years their progeny, which were accidentally poisoned by 

 verdigris mixed with the refuse tallow from the engine, were 

 taken out by wheelbarrows-full. Gold-fish are by no means 

 useless inhabitants of these dams : they consume the refuse 

 grease, which would otherwise impede the cooling of the 

 water by accumulating on its surface," 



A few authentic notices of the power of fishes in bearing 

 extremes of high and low temperature may not improperly be 

 introduced here. 



" Desfontaines found a Sparus of Lacepede, the Chromis 

 of Cuvier, in the hot waters of Cafsa in Barbary, in which 

 Reaumur''s thermometer rose to thirty degrees, equal to 

 eighty-six of Fahrenheit. Shaw saw small fishes of the 

 Mullet and Perch kind in these springs." — Travels in Bar- 

 bary, folio edit. Oxford : 1738, p. 231. 



Saussure, speaking of the hot springs of Aise in Savoy, 

 says : " I have frequently examined the temperature of these 

 waters at different seasons, and have always found it very 

 nearly alike (about 113 Fahr.). Notwithstanding the heat 



