CRANE i Pumping Machinery. 309 
suction, which is accomplished by a stuffing box, and acts as 
a continuation of the same, thus increasing or decreasing its 
length as it is drawn down or pushed up. It also prevents 
obstacles entering the column pipe and so interfering with 
the working of the valves. Both working barrel and suction, 
complete, are shown in figure 2, plate X LIII. 
METHOD OF LENGTHENING CoLuMN Pipr.—As the sinking 
Operations advance and the sump is deepened, the column 
pipe must be lengthened to maintain its position at the bot- 
tom of the shaft or in the sump. ‘This is accomplished by 
having different lengths of column pipe, which vary from five 
to twenty feet, generally in lengths of five, ten, fifteen and 
twenty feet. When the sump has been sunk far enough to 
make way for a five-foot length of pipe, the sleeve is pushed 
up as far on the suction as it will go, which will be nearly 
its own length; both suction and sleeve are then removed to- 
gether and a five-foot length of pipe put onto the end of the 
working barrel. The suction is then fastened to the lower 
end of the new length of column pipe and the sinking and 
pumping operations resumed. The sleeve is slipped down 
upon the suction as the sinking of the shaft proceeds until 
the end of the suction is again reached, when the sleeve again 
is pushed up and the five-foot length of pipe removed, a ten- 
foot length being put on in its place, and in the same man- 
ner a fifteen- and twenty-foot length is added. At this point 
the twenty-foot length of pipe, together with the working 
barrel, is removed and the two interchanged, when the five- 
foot length is again started with, proceeding upward to the 
twenty-foot length. With every twenty-foot length of pipe, 
and the consequent change of working barrel, an addition is 
made to the pump rod, thus allowing the valve in the working 
barrel to maintain its position with respect to the surface of 
the water in the sump (also with the connection above), 
which will vary from eight to ten up to twenty-five feet, and 
will be the actual height of suction. 
WoRKING OF BARREL VALvES.— The valves used in the work- 
ing barrel are of several varieties. J, figure 82, is a form of 
valve occasionally met with in the mines of the district. The 
