Wirtz’s Pump.

363

Chap. 9.

to the shanks of the cocks, which they opened and shut in the same man-ner as shown in No. 160. A sirailar contrivance may be seen in severalold authors—it is in the Spiritalia: Decaus, Fludd, Moxon and Switzerhave all given figures of it. The quantity of water raised from the shaftcompared with that expended from the spring was as 42 to 100.

By arranging a series of vessels above each other and connecting themby pipes as in No. 163, water may be raised to almost any height, in lo-cations that have the advantage of a small fall. The distance betweenthe vessels not exceeding the perpendicular descent of the motive column,which last is made to transmit its force to each vessel in succession—forc-ing the contents of one into the next above, and so on. Such a machineis interesting as showing the extent to which the principle of Heron’sfountain may be applied, but for practical purposes it is of little value. Itis too complex (if made self-acting) and too expensive for common use ;and it is far inferior to the water ram. It was described by Dr. Darwin,in his Phytologia, to which modern writers generally refer, but it is anold affair. It is figured by Moxon in his “ Mechanick Powers,” Lon. 1696,and is mentioned by older authors. It is substantially the same as thedouble fountain of Heron, as found in the Spiritalia and the works of mostwriters on hydraulies.

By far the most novel and interesting modification of Heron’s fountainwas devised in the year 1746 by H. A. Wirtz, a Swiss pewterer or tin-plate worker of Zürich . It is sometimes named a spiral pump, and wasmade to raise water for a dye house in the vicinity of that city. What thecircumstances were that led Wirtz to its invention we are not informed—whether it was suggested by some incident, or was the result of reasoningalone. It is represented in the illustrations Nos. 165 and 166, the firstbeing a section and the latter an external view.

No. 165. Section of Wirtz’s Pump. No. 166. View of Wirtz’s Pump.

Wirtz’s machine consists either of a helical or a spiral pipe. As theformer it is coiled round in one plane as A B C D E F in No. 165. Asa spiral it is arranged round the circumference of a cone or cylinder, andthen resembles the worm of a still. The interior end at G is United by awater tight joint to the ascending pipe H. See No. 166. The open end