130 WALL AND WATER GARDENS 



they do not slavishly follow the circle of the tub edge, 

 but rather serve to mask it. These stones may be 

 anything from two inches to four inches thick. Now 

 the little channel must be made that supplies the 

 water. It will look best if it is of the same stones, 

 some larger and some smaller, laid as a kind of rough 

 little trough on a bed of cement, so that the water is 

 carried without loss. There will have to be also a 

 slight ridge of cement and stones between the main 

 stones that cover the tub edges, so that the water shall 

 be compelled to flow onward, and not be lost over the 

 edge ; this can still be kept so informal that the round 

 rim is not defined. The same kind of channel will 

 connect all the tubs. It will be quite enough in a 

 small space if there are five of the tubs for true 

 aquatics. My choice for these would be the little 

 white-flowered Nymphaa pygnuza, and the pretty pale 

 yellow seedling from it called Helvola, raised by M. 

 Marliac ; then one tub each for Pondeteria, Aponcgeton, 

 and Butomus. Other tubs could be sunk for the marsh 

 plants, but if the service barrel ful of water could by 

 some clever way of diversion be given alternately to 

 the tubs themselves and to the ground around them, 

 this ground being sunk just below the path level would 

 keep fairly moist. It would, however, be a more 

 effective place for marsh plants if the whole excavated 

 space had on the sides and bottom a coat of rough 

 cement concrete followed by a finer coat trowelled on 

 or " rendered " as a bricklayer would say. 



The insides of the paraffin barrels will be made all 

 the more durable if they are burnt out before using. 



