CXXVI. DISCUSSION. 
that it took twenty minutes to pump 500 tons of silt into the 
hopper, this seemed a large proportion of power for work done. 
Mr. BarractoueH said he would like to ask a question as to 
the indicator diagrams he saw being taken, as to the power 
developed in the cylinders, and the point of cut-off, this would 
appear to have been considerably past the half stroke. 
Mr. GrimsHaw would like to draw attention to some points 
relative to the sand pump. The work could not be done with any- 
thing like the economy if rolling plant were used. In the latter 
case the cost would certainly run up to something like 1s. per 
cubic yard as against 14d. to 3d. per ton. He saw three dredges 
during their recent inspection, all useful in their particular ways. 
First there was the combined sand pump, which could also be 
used as a grab dredge, and in addition this could be used as a floating 
crane, a very useful feature where small harbours were concerned. 
The second was the “Neptune,” its chief advantage being that it 
had a hopper and could either carry the stuff out to sea, or pump 
it ashore as might be required ; it could move about independent 
of a tug, and in fact be used asa tug. The third, the “Groper,” 
although the most powerful, could not be applied to any other pur 
pose than dredging, and therefore is only suitable where large 
areas have to be reclaimed and where a hard bottom requires to be 
broken up by the cutters. The very great economy gained by 
pumping the silt ashore as against the old method of landing it 
by barrows is very apparent—the landing in barrows costing at 
least 44d. per ton, and when there is no lead, running up to 84. 
or ls. for a comparatively short lead. He could very well imagine 
that as Mr. Houghton had said, there appeared to be a great loss 
of power. In sucking up the silt and driving it through the pipes 
for so great a distance considerably more than theoretical power 
was required. The few men required to work one of these 
pumps was remarkable, as compared with the number that would 
be needed to shift the stuff with barrows. This class of dredge 
had made reclamations possible, where under the old system of 
. doing the work, they would have been impracticable on account 
. 
