Drainage by Sieam Power. 51 



by engineers whose experience was acquired in mining dis- 

 tricts, where most excellent results were obtained from pumps 

 of the bucket type. Trials of bucket pumps have given out 

 as useful an effect as any others here mentioned ; but, as the 

 pumps were designed for working at much higher lifts than 

 those required for land drainage purposes, these trials do not 

 afford a guide, the proportion of efficiency moie rapidly 

 diminishing as the lift decreases than in centrifugals. From 

 the construction of these pumps, they are not adapted for a 

 varying lift ; and in cases where they have been applied to 

 fen drainage, the water has always to be lifted higher than it 

 need be, that at Marton raising the water as much as 6 feet 

 higher than necessary. The valves and working parts are 

 also ill-adapted to cope with water charged with mud and grit, 

 and the weeds and pieces of wood which frequently find their 

 way to the inlet. 



Scoop Wheels verstis Centrifugal Pumps. — The ques- 

 tion as to whether the scoop wheel or centrifugal pump is the 

 better machine for draining land has been much debated, and 

 the matter is still a subject of controversy. The older class of 

 fen enginemen and managers place implicit faith In the scoop 

 wheel, and believe it to be superior to all other machines. When, 

 however, wheels have been replaced by efficient pumps the 

 result has been so satisfactory that the author has never met 

 with an engineman who would wish to return to his scoop 

 wheel. Such instances have occurred, and the pump been 

 removed and replaced by a wheel, but only whei'e the pumps 

 were of the most inefficient character and improperly driven. 

 The pump being a machine of superior character needs more 

 intelligence on the part of the person in charge, and, as with 

 all other machines, requires care and skill in the driving. 



This question was some time ago referred by the Dutch 

 Government to a Commission, with instructions to report as 

 to the best machine for raising a given quantity of water— -in 

 this case 140 tons a minute — to a height varying between 



E 2 



