6 THE TANK. 



plenty of holes and fissures ; tlie fire fastens these 

 firmly together and makes them as hard as stone. 

 Grooves are left along the bottom, and up the two 

 ends, for the glass to fit into. The outside is 

 relieved with ornamental work. Cheapness is a 

 great recommendation ; the pot being charged Id. 

 or 2d. per hundred cubical inches, according to 

 the amount of ornament. I should think your 

 London potters would make something very neat, 

 and the mould once made, they could be supplied 

 very cheaply ; and considering their freedom from 

 leakage and their strength, I think they would 

 prove as satisfactory as any kind of cistern. Mine 

 are about three feet long, and thirty inches high 

 and broad, holding thirty gallons each. I bed the 

 glass with w^hite lead, leaving about a quarter inch 

 in depth of the groove unfilled. When the putty 

 is set, I fill it up with shell-lac dissolved in naphtha 

 and made into a paste with whiting. This sets 

 very quickly, becoming as hard as stone ; it is quite 

 insoluble, and prevents the water from coming in 

 contact with the lead, which I think must con- 

 stantly be giving off small quantities of oxide." 



In reply to some inquiries of mine, the same 

 gentleman writes me further as follows : — 



'' I have delayed replying to you respecting the 

 price of pottery for Aquariums till I had an oppor- 

 tunity of seeing the party who made mine. The 

 price of one such as you name would be 6s. or Ss., 

 l3ut, as it would weigh four hundredweight, the 

 carriage to London would be quite as much. He 

 was rather doubtful whether with his coarse clay 

 he could make one the length you name to hold 

 together; as two or three of mine, which were 

 shorter, separated in the middle w^hen being burnt^ 



