rrKiNrjTON.] 
HVDKAILIC MINING. 
131 
the mallet. Another device used in Oregon for assistance in setting 
and unsetting pipe is shown in fig. 26. The wrench is made with 
reversible parts, so that the position of the leverage can be changed 
for the different operations. Either of these devices can be easily 
made on the ground. 
In cold climates it has been found good practice to lay the pipe line 
in a slight lateral curve 
down a slope, so that sub- 
sequent contraction of the 
units may be remedied by 
pushing the pipe into a 
more nearly straight line. 
In laying the pipe line a 
funnel-shaped section of 
pipe for the water to run 
into is usually provided at 
the pressure box. This is 
of light gage and is 6 feet 
long and from 40 to 30 
inches at its larger end. 
From this the pipe is gen- 
erally of uniform diameter 
as far as the Y or iron gate, 
from which the water is 
distributed to various parts 
J of the operations. The 
pipe should be laid* as 
j nearly straight as condi- 
tions will allow, and elbows 
'and bends of small radius 
should be avoided. 
Lead joints are seldom 
necessary in Alaska opera- 
tions, but where there are 
sharp declivities pipe 
joints must be braced and 
Strengthened by means of 
Jugs and wiring, as illus- 
trated in fig. 27. It is sel- 
dom possible to lay pipe on the " hydraulic grade line." This is "an 
maginary straight line, extending from a point on the side of the 
ivater box or reservoir, denominated the velocity head, to the mouth 
)f the nozzle." When the pipe line departs greatly from the hydraulic 
£rade line, allowances based on formulas given in the various text 
)ooks on hydraulic mining must be made for the difference in pressure. 
Fig 
•Forms of pipe fittings. 
Pipe cut, formed, ant. 
punched, to be rivited on ground; 2, pipe nested for ship- 
ment; 3, reducing length: 1, circular bend; 5, angular bend; 
6, short angular bend; 7, T discharge; 8, angular T discharge; 
'.), two-way Y; 10, three-way Y. 
"Van Wagenen, op. cit., p. 
