VOL. XXVIII.] PHILOSOPHICAL TRANSACTIONS. 47 



into these natural ponds, where they continue all summer ; no person having 

 yet observed trouts to breed in ponds. Not only the trouts, taken in these 

 mountainous lakes, are small, but also the charrs taken as they ascend the small 

 river, out of the great lakes nigh Lhan Berys, to deposit their spawn in the 

 sands there. These very rarely exceed a fresh herring in magnitude, and they 

 are in no respect different from those taken in Winander-Meer, excepting in 

 magnitude, where it is no rare thing to meet with them of 2 pounds weight, 

 and upwards. This smallness in the fish I have some times thought to proceed 

 from the coldness of the water, these lakes being supplied with snow-water 

 from the mountains 8 months in 12. The minera of vitriol and alum, being 

 often met with, in the hills through which some of the water must drain, per- 

 haps does not a little contribute to the roughness and coldness of the water. 

 The contrary we find in our waters that run through the lime-stone rocks, 

 where no rough salts are found; the trouts there are large and fat. An instance 

 of which we find in the trouts in Malham Tarr, in Craven, near Setle, where 

 they are frequently found 2 feet long. 



I must also take leave to correct one mistake in Mr. Ray's Synopsis Qua- 

 druped. &c. p. 195, where he says, that mustela vulgaris is called here a foumart 

 or fitchet, Putorius is called here a foumart, quasi foul mart, or stinking mart, 

 in opposition to the martes which emit a musky smell, and are often met with 

 in our woods, and taken by the hunters in snows. 



The ermin* is not unfrequently met with here in winter, and when they ap- 

 pear, are thought to presage snow. I should not here have taken notice of it, 

 it being also met with in most counties of England, but that I have had an op- 

 portunity, in two or three instances, of observing the time of its changes. It 

 begins to change its colour from brown to white, about the beginning of 

 November. I had one of them brought me about November two years since, 

 when I first observed this change. I have seen one or two of them, that in the 

 beginning of March were changing from white to brown. Quere, whether 

 these animals do not always continue white in the more northern parts of the 

 world ? 



The nut-hatch,'}- or nut-jobber, is not frequently to be met with in the south, 

 yet is so common with us, that I have sometimes seen 6 or 7 of them in one 

 day in my own woods. This must be the bird that Dr. Plot, in his Nat. Hist, 

 of Oxfordshire, calls a wood-cracker, and takes to be an undescribed bird. I 

 have with much pleasure often observed these birds to crack nuts, which they 

 do with great dexterity. I ordered one of my servants, that was with me in a 



* Mustela erminea. Linn. Gtnel. f Sitta Europaea. Linn. 



