MACHINES USED IN HORTICULTURE. 



155 



a case in which this syringe, and also the discharge-tube (c), are in- 

 closed ; d, a small hole in the side of the discharge tube ; and e, a valve 

 at the bottom of the discharge tube :/is a ball-valve to the suction tube, by 

 which the water is drawn up from a watering-pot, pail, or any other vessel. 

 On the motion of drawing up the piston (a), the water 

 enters by/; while, by pushing down the piston, the 

 valve at / is closed, and the water is forced up the 

 valve at e, into the discharge tube ; but as some more 

 water is forced into this tube than can pass through 

 it, it escapes by the small opening at d into the vessel 

 of air in which the working barrel and the discharge 

 tube are encased. As the air cannot escape from this 

 vessel, it is necessarily compressed by the water which 

 enters through the small opening at d ; and, conse- 

 quently, when the piston, a, is drawn up, and no longer 

 forces up the water in the discharge tube, c, the action 

 on that tube is kept up by the expansion of the com- 

 pressed air which shuts the valve at e, and, conse- 

 quently, forces the water along c. The great beauty 

 Fig. 82. section of Read's of this arrangement is, that no exertion of the operator 

 pneumatic hand-engine. j s J 08 t - nor can he exert himself without producing 

 a corresponding result ; for if, by rapid and powerful action, he drives much 

 water into the air vessel, the greater degree in which the air is compressed will 

 force the water with the more rapidity through the discharge tube, c. This 

 engine is 3 ft. long, and 2^- in. in diameter ; it weighs only between 51b. and 

 Gib. ; works with remarkable ease, and is so little liable to go out of repair, 

 that Mr. Read warrants it to last a lifetime. Read's barrow engine, fig, 83, 

 is an oval copper vessel, containing twenty-six 

 gallons, particularly adapted for large conser- 

 vatories and forcing houses. It will pass 

 through a door- way two feet wide, and is so 

 portable that it may be carried up or down 

 stairs by two men. The great power of this 

 engine depends on the air vessel, indicated by 

 a dotted circular line, in the body of the en- 

 gine, in which all superfluous force is em- 

 ployed in condensing air, as in Read's pneu- 

 matic engine, so as to form a reservoir of 

 power ; and in the proximity of the bent ful- 

 crum, a, to the handle or lever, &, by which 

 the weight c, being brought near to the ful- Fig. 83. Read's barrow engine. 

 crum, the power applied at b is proportionably increased. In most engines 

 of this kind there is no pneumatic reservoir, and the distance between the 

 weight, c, and the fulcrum, a, is much greater. The construction of the pis- 

 ton, valves, &c., is similar to that of Read's hand-engine, so that this barrow- 

 engine is not only a machine of great power, but not liable to go out of 

 repair. Mr. Read, who has been attending to this subject the greater part 

 of his life, considers this engine as his masterpiece. 



441. Garden-bellows. Bellows are used hi gardening for dusting plants 

 with powdery substances, such as quicklime, powdered tobacco leaves, sul- 

 phur, &c., and for fumigating them with tobacco-smoke. Read's fumigating- 

 bellows (figs. 84 and 85) answers both purposes. It consists of a pair of 



