Chap. 6.J

Pumps in German Mines.

219

No. 88. Pump and Pistons fromAgricola.

cola, were similar to such as were used in some of the same mines by the

ancients, and have always formed part ofthe machinery for discharging water from

K CJL them since the fall of the Roman empire.

I* |T\J« All that are ligured in the De Re Metallica,

are extremely simple, and with one excep-tion are atmospheric or sucking pumps.They are all of bored logs. Some are sin-gle pumps, and are worked by men withlevers, cranks, and also by a kind of pendu-lum. Others are double, triple, &c,, andworked by water wheels. Of the last someare arranged in rows, and the piston rodsraised by cams as in a stamping mill; theweight of the rods carrying them down.Others are placed in tiers one above ano-ther; the lowest one raises the water fromthe bottom of the shaft or well, and dis-eharges it into a reservoir at its upper end:into this reservoir the next pump is placed,which raises it into a higher one, and so onto the top. A pump of this kind from Ag-ricola, has been often republished. It waseopied by Bockler and others. A figure ofit is inserted in Grregory’s Mechanics, Ja-mieson’s Dictionary , &c.

We have selected No. 88, as a specimenof a single pump, and of upper and lowerboxes. A, A, represent two of the latter ; the upper part of one is tapered tofit it into the lower end of the pump log as is yet sometimes done. D, B, anupper box, of a kind occasionally used at the present time. The valve or

clack is a disk laid loosely overthe apertures, and is kept in itsplace by the rod, which passesthrough its centre and admits itto rise and fall. C, the conicalsucker referred to, p. 214.

The annexed figure of adouble pump is from Fludd’sworks. It appears to havebeen sketched by him while inGermany , from one in actualuse. It is represented asworked by a water wheel,that, by means of cog wheelstransmitted motion to the hori-zontal shaft; the cams on whichalternately depressed one endof the levers to which the pumprods were attached, and thusraised the latter. They de-scended by their own weight,as will appear from an inspec-öon of the figure. The separate view of a rod is intended to show theapplication of cranks on the horizontal shaft, in place of cams and le-

>. Double Pump in German mines. A. D. 1618.