It is always desirable to sink a cast-iron well, such as that at the Horse Fort, as nearly as possible down to the level at which the water stands in the bore-hole. The sinking of such a well is rendered an easy and rapid operation, with the aid of the boring machine in winding out the material from the bottom, and keeping the sinkers dry by the use of the dip-bucket, shown in Figs. 214 to 216, which will lift from 50 to 100 gallons of water a minute, for taking off the surface drainage. A well having thus been made down to the level of the water in the bore-hole, the permanent pumps are then applied to the bore-hole as follows, the size of the pumps varying according to the diameter of the bore-hole. Taking the case of a 15-inch bore-hole, a pump barrel consisting of a plain cast-iron cylinder, say 12 inches diameter and 12 feet long, as shown in section in Fig. 219, is attached at the bottom of cast-iron or copper pipes, which are 1/4 inch larger in diameter than the pump barrel, and are coupled together in lengths by flanges, Fig. 217. By adding the requisite number of lengths of pipe at the top, the pump barrel is lowered to any desired depth down the bore-hole: the nearer to the depth of the water-bearing strata the better. The topmost length of pipe has a broad flange at its upper end, which rests upon a preparation made to receive it on the cast-iron bottom of the well, as at C in Fig. 219. [Illustration: Dip Bucket. Figs. 214, 215.] [Illustration: Sectional Plan. Fig. 216.] [Illustration: Joint of Copper Tubes. Fig. 217.] [Illustration: Couplings of Pump Rods. Fig. 218.]