9^3 THE AQUAEIUM. 



MY OWN TANK. 



As the principal subject of these pages is the Marine 

 Aquarium, including, and indeed subsidiary to, the 

 history of the plants and animals which it enables us 

 to keep under our observation, it may not be imperti- 

 nent in me to give some account in detail of my own. 

 Hitherto I had contented myself with cylindrical glass 

 vases, ten inches in height and five in diameter, which 

 answer admirably for small objects ; with wide shallow 

 pans of yellow and white ware ; and with a foot-bath 

 of the latter. These, though affording opportunity 

 for many interesting observations, were deficient in 

 some points, which would be supplied by a tank of 

 ampler dimensions, with parallel sides to prevent 

 unequal refraction and consequent distortion, and 

 made wholly of plate-glass, to allow distinct vision 

 in every part. 



Such a vessel I have had made under my own direc- 

 tion ; and as it will be the chief medium of most of 

 the notes that occur in the subsequent pages of this 

 work, I will describe in detail its dimensions, form, 

 and structure ; the mode in which I filled and stocked 

 it ; with some accounts of failure and disappointment 

 to serve as beacons, as well as of success to stimulate 

 with encouragement. I do not hold it up as a perfect 

 example, but as an essay actually made, '^ with all its 

 imperfections on its head." 



The tank is 2 feet long, 1| foot wide, 1^ foot deep; 

 the sides and ends of y^ths plate-glass ; the bottom 

 of slate ; the corners of birch-wood, tm-ned into pillars, 

 each surmounted by a knob, and united by a frame top 



