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PS BULLETIN 300, U. S. DEPARTMENT OF AGRICULTURE. 
to permit the material to be dug and thrown out in one operation, 
it was necessary to rehandle the dirt with shovels or to carry it out 
in baskets or wheelbarrows. These methods were very slow and 
expensive. Although the ditches then constructed served their pur- 
pose for the small agricultural tracts, which were generally on high 
ground, the increase in population and the resulting spread of agri- 
cultural operations to the lower lands soon demanded the construction 
of larger channels. Teams and scrapers were then used where con- 
ditions permitted. If the material was hard it was first loosened 
with a plow and then removed by means of shp or wheel scrapers. 
This method, however, became too expensive when still larger ditches 
were required. Moreover, drainage channels must frequently be 
constructed on lands so wet and soft as to preclude the use of teams. 
The increasing demand for suitable excavating machinery engaged 
the attention of many men of mechanical bent, and the result has 
-been the invention of modern types of machinery, the development 
of which has been rapid. By the use of modern machinery the cost 
of drainage work has been so reduced as now seldom to afford valid 
excuse for failure to drain. 
The early type of dipper dredge was equipped with the old-fash- 
ioned vertical spuds, and the hull was built wide to prevent tipping. 
The ditches desired at that time usually were small, and owing to the 
width of hull the operator was nearly always compelled to excavate 
more material than he was paid for., The bank spud, which runs 
directly from the side of the machine to the bank, was invented to 
do away with this unnecessary width of hull and consequent useless 
excavation. Although many delays and difficulties were encountered 
in the early stages e development, the cost of excavation by ma- 
chinery was soon reduced much below that by hand labor. That 
achievement marks an epoch in the progress of drainage in this 
country. 
In late years the so-called dry-land excavators of various types have 
been developed and have reduced the cost of excavation under con- 
ditions to which floating dredges are not adapted. The growth of 
the drag-line scraper excavator has been especially prominent. At 
present jane machine probably has a wider field of usefulness than any 
other type of excavator made. 
COMPARISON OF KINDS OF POWER. 
Excavating machinery may be operated by steam or internal-com- 
bustion engines or by electric motors. Coal, wood, and crude oil are 
suitable fuels for steam generation. Internal-combustion engines” 
operate with gasoline. kerosene, or distillate. Electric current must 
be conveniently available and low in cost if motors are used, and if 
