. The railroad and engineering journal . in. wrought-iroii plaie. ni uvo seclions, moriisedtogether, and is let into rabbets in the walls and securedby screw bolts. The turret is mounted upon what is calleda floating pivot. It rests upon a built-up annular boxgirder, which in turn is secured by means of brackets to aheavy casting that rests upon a lo|-in. steel pivot, aboutwhich the turret revolves. This pivot rests in a steel-linedcast iron cylinder containing glycerine, which supports theentire weight of the structure—someihing over 100 means of a hand pump the whole movable portion
. The railroad and engineering journal . in. wrought-iroii plaie. ni uvo seclions, moriisedtogether, and is let into rabbets in the walls and securedby screw bolts. The turret is mounted upon what is calleda floating pivot. It rests upon a built-up annular boxgirder, which in turn is secured by means of brackets to aheavy casting that rests upon a lo|-in. steel pivot, aboutwhich the turret revolves. This pivot rests in a steel-linedcast iron cylinder containing glycerine, which supports theentire weight of the structure—someihing over 100 means of a hand pump the whole movable portion ofthe turret can be raised so that little or no weight rests uponthe rollers. The turret is revolved by means of a double-purchasewinch in the lower chamber. Horizontal and vertical roll-ers, upon a track of cast-iron bolted to the top of the pitwall guide and control the motion of the turret, but do notsupport its weight. The two guns are mounted side by side, and to facilitatemanceuvring, are each provided with a counterpoise weight. suspended in front of the central pivot, but having a pre-ponderance of 1,100 pounds. The recoil is taken up bymeans of small hydraulic cylinders under the gun, oneabove the other, the piston in ihe upper cylinder being con-nected with the carriage. The opening between the cylin-ders is closed by a one-way valve which opens automati-cally during recoil, the force of which is made to compressa strong spring. By opening this valve the spring is re-leased and the gun run into battery. Excepting the gun-ports, there are no openings of anykind on the side toward the enemy, a door affording in-gress and egress from the rear. Except the view obtainedthrough the bore of the piece, the gunner has no meansof knowing the character or position of the object aimedat other than from information received from the observingstation some distance away. The guns have no sights ;the elevation is given by quadrant. By means of a melalring, graduated to degrees and
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Keywords: ., bookcentury1800, bookdecade1880, booksubjectrailroa, bookyear1887
