54 The Drainage of Fens and Low Lands. 



their way in Holland, as out of 139 machines put up, 50 were 

 centrifugal machines, 38 were scoop wheels, 30 screw pumps, 

 4 piston pumps, and the others of various types. Out of the 

 57 machines erected in recent years by Messrs. De Witt, 

 engineers, of Amsterdam, 31 were centrifugal pumps, 9i were 

 Archimedean screws, and 3 were scoop wheels. The centri- 

 fugal pumps generally used in Holland are direct acting, 

 having horizontal spindles, the discs placed above the water 

 level. The turbine form has been tried, but the results were 

 not favourable. 



With regard to the relative merits of scoop wheels and cen- 

 trifugal pumps in the quantity of coal consumed, the general 

 weight of opinion amongst engineers in this country who have 

 had an opportunity of comparing the relative merits of the two 

 machines is decidedly in favour of the centrifugal pump. This 

 question was thoroughly investigated about ten years ago by 

 Mr. J. M. Heathcote, of Conington Castle, a gentleman who 

 was not only the owner of land drained by steam power, but 

 was greatly interested in fen drainage. As the result of his 

 investigations, Mr. Heathcote came to the conclusion that the 

 pump was decidedly the more economical machine, and in this 

 he was supported by facts and figures from other sources fur- 

 nished by Messrs. Easton and Anderson. These, however, 

 while useful so far as they went, were not drawn from actual 

 trials of the two machines working under precisely similar cir- 

 cumstances. The nearest approach to this is the running of 

 the two sets of machines over a series of years for the drain- 

 age of the Wexford Harbour reclamation, particulars of which 

 will be given hereafter. For the three years 1881, 1882, 1883, 

 the consumption of coal at these two pumping stations was 

 about one-third in favour of the centrifugal pumps, or at the 

 rate of 18*65 pence per acre for the land drained by a pump, 

 and 26*30 pence for that drained by a scoop wheel. The latter 

 was of modern construction, and the lift in each case the 

 same. 



