174 SALMONIA. [seventh day. 



are never found in streams that run from glaciers — at 

 least near their source ; and they are killed by cold or 

 heat. I once put some grayling from the Teme, in 

 September, with some trout, into a confined water, 

 rising from a spring in the yard at Downton; the 

 grayling all died, but the trout lived. And in the hot 

 summer of 1825, great numbers of large grayling 

 died in the Avon, below Kingwood, without doubt 

 killed by the heat in July. 



POIET. — But I have heard of grayling being 

 common in Lapland— at least so says Linnaeus. 



HAL. — I think it must be another species of the 

 same genus, the same as Back's grayling found by 

 Captain Franklin and his companions in North 

 America, and distinguished by a much larger back fin. 

 Having travelled with the fishing-rod in my hand 

 through most of the Alpine valleys in the south and 

 east of Europe, and some of those in Norway and 

 Sweden, I have always found the charr in the coldest 

 and highest waters ; the trout, in the brooks rising in 

 the highest and coldest mountains; and the grayling 

 always lower, where the temperature was milder ; and 

 if in hot countries, only at the foot of mountains, not 

 far from sources which had the mean temperature of 

 the atmosphere, — as in the Yipacco, near Goritzia, 

 and in the streams which gush forth from the lime- 

 stone caverns of the Noric Alps. Besides temperature 



