The floor will be three inches thick ; but before laying it the soil at the base of the previous piece of cementing should be scraped away to a depth of three inches ; this will allow the cement to run under and so make a good joint. The ledge for keeping in the soil is not made with the shelf, it forms part of the next operation.

The side and floor of the shallow part are finished now and should be kept slightly moist to prevent quick drying. The excavation of the deeper area now commences. In the centre of this we must construct a ' soak-away ' and so we will dig as far down as we can, five feet or more. A piece of drain pipe is stood on end and around it is rammed rubble, brick- bats, stones and the like until the floor is brought up to within two feet of the previous cement work. The drain pipe is now firmly fixed in the earth and projects about five inches above the soil.

The soak-away usually functions very slowly, according to the nature of the ground, and may take four or five hours to empty a thousand-gallon pond. Nevertheless, in order to prevent the more adventurous fishes and snails from entering the pipe, a piece of wire gauze made into a cap may be placed over the end of the pipe or inserted in the pipe itself. Moreover, do not go away and forget that you have removed the plug, otherwise you may find your fishes floundering about in an inch or so of water. (Figs. 8 and 9.)

Next, with the shuttering used for the first stage of the work, we prepare the side of the deep area for the cement. Just as we undercut the soil to make a good joint for the shelf so must we undercut the soil at the edge of it ; thus the side now under construction will bond well.

The spacers should project some three or four inches above the cemented floor, thus, when the cement is placed between shuttering and earth, the ledge previously referred to will be formed. The deepest part in the centre should have a diameter of three feet, consequently the sides will be so made as to slope from the six feet diameter at the edge of the shelf to that diameter.

The pond is now completed save for the floor of the deepest part. Undercut the cement of the sides as before and fill in to a depth of four inches with cement.