FORM, SIZE, AND MATERIALS. 7 



from the great weight of the ends preventing the 

 centre contracting regularly. He thinks your best 

 plan would be to get one of the terra-cotta workers 

 to make one, which he thinks he would do more 

 cheaply than it could be sent from here ; and their 

 clay being finer, a much neater article could be 

 made. It would be well to be on the spot, and 

 see the rough clay put on the ends, as workmen in 

 general have not much idea of what is required. 



" To prevent the water filtering through the 

 pots, mine were well glazed inside with flint-glaze, 

 free from lead. Probably it would be better to 

 glaze the outside, and leave the inside porous." 



If a cylindrical form of vessel be preferred, it can 

 be obtained without any material but glass in the 

 construction. A very pleasing Aquarium, whicli 

 has the advantage of cheapness, is greatly in request, 

 formed of a propagating glass turned upside-down, 

 and set on a stand of polished mahogany or rose- 

 wood. This form has cylindrical sides, and a 

 rounded bottom, terminating in a knob, which being 

 inserted into a cavity in the stand, gives security 

 to the whole. The bottom should be covered with 

 sand or earth to a height sufficient to bring it up 

 to the level of the cylindrical sides, for the conve- 

 nience of observation. Vessels of this shape are 

 now made up to 20 inches in diameter. 



Confectioners' show-glasses are very suitable for 

 small specimens ; they are usually about twice as 

 high as broad, and are therefore the more graceful. 

 These afford peculiar facilities for the examination 

 of their contents with a lens, as they can be easily 

 moved round, and may be placed before a candle 

 or lamp for nocturnal investigations. They may 

 be had of various sizes, from three to eight inches 



