SYPHOJf ON A LARGE SCALE. * J3 



On the top of the cooling veflel A, Fig. 1 . Plate V. let a A veffel filled 

 fmall veflel B, called the air-veffel, be placed, communicating ^j.'^^,nTtop'^^ 

 with A by a cock. With the top of B let another veflel C, and another at 

 called the zvater-vefd be conneaed, having a cock C. Thefe ^"^^"J withX 

 cocks have two parallel openings each, one for letting out air, upper partof chc 

 the other for letting in water at the fame time to take '^s ^J^^-^^^jj'jj^^ 

 place. Suppofe thefe three veflels to be filled with water cock only is 

 and the fyph4m in adtion, the cock B open and C fliut ; then opened the ex- 

 all the air produced in the cooler will rife through B and fill afcends, and 

 the air-veflel ; and in the mean time the water will defcend. water defcends. 

 The air-veflel being filled with air, let the cock B be fhut, ^J'^"^^^^,^PP" 

 and C opened ; then the water from C will defcend, and the opened, the air 

 air will efcape into the atmofphere. By this alternate motion oj^gf ^aJej^^fjug 

 of the cocks, the air difengaged within the worm-tubs will in fiomaboTc. 

 be continually extracted, as long as any water remains in C, 



. The principal object then mufl: be firfl to fupply the water The upper water 

 in C, either by manual labour, or by a part of the mechanical "^jftheSl"'^' 

 force employed to fill the artificial refervolr for the lower muft work with- 

 branch of the fyphon ; and fecondly, to dired the alternative «"' «"'=^^'^^"^«- 

 opening of the cocks, by a felf- regulating mechanifm ; which 

 may be effeded in the following manner. 



Fig. 2. Plate VI. reprefents a fe6lion of the air-vejfel B, The cocks are 

 B is the air and water-cock, communicating with the worm- flgat:'^ which 

 tub or cooler beloWi A is the other cock for the fame when at loweft 

 purpofe, communicating with the water-veflel C. A and B 3^^^^ ^^^''5"^^'^'^ 

 being connedted by a metallic rod K L, their motions are fimul- upper cock ; and 

 taneous, and the perforations are fo placed^ that when the when at highcft 



. ^, , r r 1 1 1 ^0^5 the con* 



twQ holes of one cock are open, thole ot the other are always trary. The 



(hut. E is a ball of lead or other weight, fixed on the lever a£tion is made 

 O U, conneded with the quadrant F G, and the lever G H, turabl?ngweight,' 

 the whole turning through one quarter of a circle round the 

 Centre U ; m « is a part of a cog-wheel fixed to and Aiding 

 along the quadrant G F, a6ling upon the teeth of the cock 

 A, and forcing it, together with the cock B, one way or the 

 other, as itfelf is moved by the levers U F or U G, either in 

 the dire^ion from F to G, or from G to F* This alternate 

 motion is produced by the floater POQR, (of which apian 

 on a diminiflied fcale> is reprefented in Fig. 3.) having in its 

 middle and hollow part a kind of fork O, through whi^h 

 pafles the metallic rod H I, conne6ted with the lever H F, at 

 the end of the quadrant GF. This floater in its afcenfion 



G2 lifts 



