FORM, SIZE, AND MATERIALS. 5 



window; it is three feet long by one foot ten 

 inches in greatest width, and the same in depth ; 

 the peculiarity is that the back slopes inward, so 

 that the bottom is but eight inches wide. I cannot 

 commend this form ; its appearance is lumbering 

 and inelegant ; the opacity of the back and sides 

 throws the interior into a degree of darkness, (even 

 though placed in a south window,) which greatly 

 impedes observation ; and I cannot see, by com- 

 parison with my others, which are of glass all 

 round, that the advantage anticipated, of admitting 

 the light only from above, is real, or at least of 

 sufficient importance to compensate the uninviting 

 gloominess alluded to. Its depth also is too great ; 

 a foot of water is as much as is needful for a 

 parlour Aquarium. 



A novel mode of constructing tanks has been 

 suggested to me by Mr. W. Dodgson of Wigton, 

 Cumberland, which, as I have not tried it, I will 

 describe in his own words. 



*' I have lately been constructing two Aquariums, 

 and as the way in which they are made may be 

 new and perhaps useful to you, I take the liberty 

 of communicating it. Slate we have no oppor- 

 tunity of procuring in suitable pieces for joining, 

 and our stone is too porous for the pur]^)ose. I 

 therefore got the bottom and two ends made in one 

 piece out of the yellow clay used for garden vases, 

 chimney-tops, and other coarse pottery, and found 

 it answered exceedingly well and has several 

 advantages. 



" Partly as a means of supporting the ends, but 

 principally to form artificial rockwork and shelter 

 for the animals, the two ends are buttressed inside 

 with very rough pieces of clay, put on so as to leave 



