MONTHLY SLTMMAEY. 255 



into a pipe, Mhich empties itself by a cascade into the canals. 

 At the other end of these it oveiilows into another reservoir, 

 Avhence it is conducted in pipes back to a great culvert, the 

 position of ^vhich may be known by a broad iron plate in the 

 walk facing the memorial on the South side of Mr. Nesfield's 

 circular composition of gravel beds in front of the great basin. 

 This large culvert, up which a man might walk, and which, 

 to conthiue the comparison of circulation, may be likened to 

 the vena cava, receives all the water on its return horn the 

 four canals, and is draAvn up by the Appold pump. This pump 

 connects or stands between the two ends of these pipes, as the 

 heart does between the veins and arteries, and like it draws 

 the circulathig fluid out of the one and throws it into the other. 

 It does so by the excessively rapid revolution of a fan, which 

 whirls round the water, exhausting it from the one pipe and 

 forcing it into the other. By this means the whole of the 

 garden water works are set in motion at once; and 5000 gallons 

 are ptissed through the pump every minute. In tw^o houi^s* time 

 it would exhaust the whole water in the canal and basins, which 

 it takes the small engine four days and four nights constant 

 working to fill. Its ordinary purpose, of course, is merely to 

 draw water out of one pipe. The forcing it into the other pipes 

 is a mere additional application of it to another use. 



The Appold pump is the work of one of those mechanical 

 geniuses, of which England has produced more than any other 

 nation. It is rather more than 19 years since, that Mr. Appold, 

 on a visit to Cornwall, saw the steam cylinders which were 

 preparing there for the purpose of draining the Haarlem lake 

 in Holland. These were being made of immense central steam 

 cylinders, 12 feet in diameter, which were to work several pumps 

 around. One set of these pumps was to pump up 250,000 

 gallons in a minute, and to discharge the contents only ten times 

 in a minute. The waste of material and x^o^'^i' struck him as 

 excessive, and on the spur of the moment he declared that 

 with the fan working in Mr, Sim's neighbouring foundry, at 

 Redruth, he would undertake to pump up more water than 

 with all that immense apparatus in preparation. His friends 

 disputed the possibility of its being so applied. He thought 

 over it, and convinced himself that it could be done. He 

 explained his views to some of his engineering friends. They 

 disputed them and would not be convinced. Stimulated by this 



opposition and incredulity (Mr, Appold declares that it Is such 



