Mr Clark's Description of a Neio Quicksilver Pump. 267 



they must be ranked with that species. From this perplexity 

 the optical method immediately relieves us, not merely by de- 

 tecting unequivocal characters in the mineral under examina- 

 tion, but by insulating, as it were, the kindred species of Anal- 

 cime and Chabasie, which possess a composite structure of the 

 most remarkable kind. 



Art. XV. — Description of a New Quicksilver Pump.* Invent- 

 ed by Mr Thomas Clark, Edinburgh. Communicated by 

 the Inventor. 



The new machine invented by Mr Thomas Clark, for raising 

 water, is a quicksilver pump, and works without friction. It 

 lias great power in drawing and forcing water to any height, 

 and is extremely simple in its construction. It is made by 

 twisting a piece of iron tube into the form of a ring, ABC, 

 Plate IV. Fig. 4, having the ends of the tube bent into the 

 centre D, and again bent outwards so as to form an axle to 

 the wheel or ring thus formed. One of the ends of the axle 

 is inserted, by means of a stuffing box at D, into the side 

 of the main pipe EF, which leads down to the well, which 

 allows it to move easily, and at the same time keeps it 

 air tight. In the main pipe EF, immediately below where the 

 axle is inserted, or at any other convenient distance, is placed 

 a valve g lifting upwards, another valve li lifting upwards is 

 also placed immediately above the axle, or at any other conve- 

 nient distance. There is now put into the iron ring a quan- 

 tity of quicksilver, filling it from Jc to I, which slides backwards 

 and forwards as the ring is made to vibrate upon its axis in 

 the stuffing box at D, forming a vacuum in the main pipe as 

 the silver recedes in the tube from A to C ; the water rushes 

 up from F to fill the vacuum, and when the silver slides back 

 again towards A, the water is expelled through the upper 

 valve h, and escapes at the top of the main pipe at i. A 

 wheel of twelve or thirteen feet diameter will lift water the 

 same height as a common lifting pump, and force it 150 feet 

 higher, without any friction. 



* Our readers will observe, that this very ingenious quicksilver pmup 

 is essentially different from that of Mr Haskins, which is described in the 

 Edinburgh Encyclopedia, Art. Pump, Vol. XVII. p. 307. 



