5), be a pair of semi-cylindrical fixed trunnions which are carried on a supporting frame and held with flat sides downwards.
Let -I- B, - B, be two smaller trunnions which project out from the sides of the two strips connecting together a pair of rings CC. The rings and the connecting strips constitute the circuit which is to be rendered movable.
I.): " Raise the sight, and if it keeps in line with a plumb bob, it can be as confidently relied upon as the line of metal, if the trunnions are horizontal.
Other improvements were: the gun was sighted on each side, tangent scales dropping into sockets in a sighting ring on the breech, thus enabling a long scale for all ranges to be used, and the foresights screwing into holes or dropping into sockets in the trunnions, thus obviating the fouling of the line of sight, and the damage to FIG.
9) consists of a telescope mounted in a steel frame, provided with longitudinal trunnions fitting into V's in the gun.
The telescopic mast is carried in trunnions on the carriage, and travels closed and in a horizontal position.
16) in which this wonderful process is carried out is a huge retort, lined with clay, dolomite or other refractory material, hung aloft and turned on trunnions, DD, through the right-hand one of which the blast is carried to the gooseneck E, which in turn delivers it to the tuyeres Q at the bottom.
When we come to pieces of very irregular shape, such as crank-shafts, anchors, trunnions, &c., we must resort to forging, except for purposes for which unforged castings are good enough.
On the upper plate are placed two small levelling bubbles, and two standards tt ate attached to the upper side of the plate for supporting the trunnions of the telescope T.
The bearings for receiving these trunnions are V-shaped; the V on one side is fixed, while the other is cut through and can be narrowed or made wider, thus lifting or lowering the trunnion by means of two capstan-headed screws.
The Y theodolite differs from the transit in that the supports for the telescope are low, that the telescope rests in a cradle the trunnions of which rest on the supports, and that a segment of a circle attached to the cradle replaces FIG.
The declination axis is here represented by what are practically the trunnions or pivots of the tube, resting in bearings which are supported by the arms of a very massive cast-iron fork bolted to the upper end of the polar axis.