HOUSE-MARTINS. 275 



they are sleeping or not, because their eyes are always 

 open. 



Nothing can be more amusing than a glass bowl containing 

 such fishes : the double refractions of the glass and water 

 represent them, when moving, in a shifting and changeable 

 variety of dimensions, shades, and colours ; while the two 

 mediums, assisted by the convaco-convex shape of the 

 vessel, magnify and distort them vastly; not to mention 

 that the introduction of another element and its inhabitants 

 into our parlours engages the fancy in a very agreeable 

 manner. 



Grold and silver fishes, though originally natives of China 

 and Japan, yet are become so well reconciled to our climate, 

 as to thrive and multiply very fast in our ponds and stews. 

 Linnaeus ranks this species offish under the genus of cyprinus, 

 or carp, and calls it cyprinus auratus. 



Some people exhibit this sort of fish in a very fanciful 

 way ; for they cause a glass bowl to be blown with a large 

 hollow space within, that does not communicate with it. 

 In this cavity they put a bird occasionally, so that you may 

 see a goldfinch or a linnet hopping, as it were, in the midst 

 of the water, and the fishes swimming in a circle round 

 it. The simple exhibition of the fishes is agreeable and 

 pleasant; but in so complicated a way becomes whim- 

 sical and unnatural, and liable to the objection due to 

 him, 



" Qui variare cupit rem prodigialiter unam." 



Who loves to vary every single thing 

 Prodigiously. 



LETTEE XCIX. 



TO THE SAME. 



October 10, 1781. 



DEAB, SIB, I think I have observed before, that much the 

 most considerable part of the house-martins withdraw from 

 hence about the first week in October ; but that some, the 

 latter broods, I am now convinced, linger on till the middle 



