MAKING AQUAEIA. 9 



zinc, solder, cement, and plate-glass. The tools necessary are 

 an old tenon-saw, square, hammer, soldering-iron, and a pair 

 of scissors made for cutting sheet metal; but besides these a 

 few blocks must be prepared. The amateur can either make 

 the blocks himseK, or he can get them made at a trifling cost. 

 I will describe them in the order in which they will be required. 



Fig. U. Steel Bab. 



Kg. 10 shows an iron block, 6jn. long, having a (J -shaped 

 groove down its centre. The groove is fin. wide and fin. deep. 

 The holes at each end of the block are for the screws which 

 fasten it firmly to the bench. It will not only be useful for the 

 purpose for which it has been made, but at any time it will be 

 serviceable as a small anvil for straightening nails and the like. 



A B 



Fig. 12. Wood Block. A, Side View; B, End View. 



Fig. 11 represents a steel bar a little less than Jin. in diameter, 

 and a little longer than the aquarium is intended to be. Figs. 

 12 and 13 illustrate blocks made of some hard wood. That in 

 Fig. 12 ought to be not less than 6in. long, and the groove in it 

 should be at least lin. deep, and just broad enough to receive a 

 double thickness of zinc. The latter has a groove exactly the 



A 



A 

 Fig. 13. Wood Block. A, Side View; B, End View. 



same size as that in the iron block (Fig. 10). Fig. 14 is made 

 of hard wood, faced with two iron plates. The groove in this 

 block must equal that of the iron block (Fig. 10), and the 

 iron plates should be just far enough apart to receive a double 

 thickness of zinc. Besides these blocks an ordinary mitre- 



