[_A Bucket-fountain._] In the present and preceding articles the water is elevated by means of buckets, and it was only while these pages were passing through the press that the author perceived those precise marks of distinction between the two methods of employing the buckets which enables him now to offer the following explanation of each. [Illustration: A Balance Water-work] As regards No. 20, it seems, at first, absurd to expect to raise water which is to be in a balance and pass from one bucket to the other. But let us suppose an arrangement, as in the subjoined engraving, where A, B, is a strong vertical wooden frame carrying six metal or wooden pipes C, C, which can be moved simultaneously up and down on centres, _a_, _a_, being connected by the iron rods, _b_, _b_; these pipes are united with the top of six buckets at D, D', and with the bottom of six other buckets at E, E'. The buckets D, D', are also connected at the bottom with six other pipes F, F, each open at the end F, F, and so arranged that the topmost pipe passes over a pulley _c_, but the other five pipes with guide rods _d_, _d_, at their ends, enter the top end of the five uppermost buckets on the side E; the pipe F, passing over _c_, delivers the contents of bucket D, while the lower-most bucket E', is being replenished, “thus the uppermost yielding its water at the same time when the lower-most taketh it in.” In the present position of the machine the pipes C, C, are inclined, and the pipes F, F, are horizontal, but when the bucket E' is elevated, then these pipes will all reverse their positions, being connected with the buckets by means of flexible leather hose, or suitable jointed metal tubing. [Illustration: A Bucket-fountain] We have next to consider the present article No. 21. The conditions stated require the use of but one pulley, one cord, and two buckets, without any “force” or pump plunger, or “any wheel, or sucker.” An arrangement so simple seems only possible to be attained by some such plan as that exhibited in the illustration given below. We have here an endless chain or cord, A B, passing over the pulley C, with a bucket D, at the upper end; and another bucket E, at the lower end; the first in the act of discharging its contents into the trough G, the second re-charging with water at the level E. This endless chain is further supplied with a series of conical or other shaped buckets, _a_, _a'_, set on the endless cord in a reverse direction, so as to receive water conveyed from an upper stream by the spout F, by which means the side B, of the cord will descend, and the side A, ascend, “without any other force than its own motion,” and that “with two buckets only, day and night.” On the side _a'_, the conical buckets reverse and empty themselves, thereby lightening the ascending side A, of the endless chain or cord. 22.