ties an elevating arc actuated by a worm-shaft and handwheel on the carriage. This trunnion also carries a panoramic sight (not shown in the illustration), mounted so as to slide on an arc which renders its position independent of the gun elevation. The base- plate, which is of steel, has longitudinal and transverse spades or flanges to enable the mounting firmly to be bedded on the ground.
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In the forepart, the baseplate has a vertical pivot and in the rear part an arc, which enables the top carriage to be traversed 12} either way from the centre line by means of the handwheel seen in the illustration. As in all German rifled trench-mortars care is taken to house in gearing and mechanism so as to keep out mud and dirt. The weight of the whole system in action is 1 ,064 Ib. and the maxi-
mum range, with a log-lb. shell (burster 241 Ib.), is 980 yards. For
transport, wooden wheels are fitted to axles on the bedplate and a
handspike with a socket formed at the back of the same. The
"new" model of medium minenwerfer is slightly longer (3-8 cali-
bres rifled length), weighs 1,232 Ib. in action, and ranges to 1,250
yd. with the same shell.
The heavy minenwerfer, new model, shown in fig. II, is similar in al essentials of design to the above, but like other new models longei than the original model of its class. The details, such as the sighi and the traversing gear seen in the illustration, and the elevating gear, etc., seen in fig. 10, are common to old and new models of medi um and heavy. The new model heavy has a calibre of 245 nun in.) and has a rifled length of 4-54 calibres. It weighs in action 1,69^ Ib. and with a 2lo-lb. shell (lO3-lb. burster) ranges to 990 yards The old model has a rifled length of 3-1 calibres and weighs ii action 1,362 Ib. ; with the above shell it ranges to 612 yd. only.
In the light minenwerfer, 7-6-cm. (2-9-in.) calibre, of which th< " new " model is shown in fig. 12 and the direct-fire carriage in tig 13, the piece, buffer and recuperator system and bedplate are similai in general to those of the medium and heavy types. But the top-- ' carriage design is entirely different. The ring-cradle (which carrir; the buffer system as in the other types) is continued on each side
to form arms which at their extremities are traversed by an axh ,
or through trunnion-bar, a few inches above the baseplate level.
This bar rests in seatings in a very small intermediate carriage
which traverses (through a circle) round a pivot in the bedplate.
In the forepart of this intermediate carriage is another cross-axle'
which at its middle is formed as a socket, taking the foot of a stout,
elevating screw. This elevating screw (which is cased in leather to,
protect it from dirt) is clearly seen in fig. 13. It supports the weight
of the cradle and piece, to which it is jointed, and elevation is
by screwing up or down.
The weight in action of this model is 312 Ib., the rifled length of bore 5-2 calibres, and the high-explosive shell weighs only 9 Ib., and, comparing these proportions to those of the heavy and medium! shell, it is not surprising to find that it ranges to 1 ,422 yards. The " old " model was somewhat shorter and lighter, and ranged to| 1,150 yd. with the g-lb. shell.
The light minenwerfer, which is also known as the " Ehrhanh. was a very successful weapon, and every German infantry bad had by 1917 a " light minenwerfer section," consisting of 4 ol " i ' pieces and a number of the " granatwerfer " described under BOMI;
THROWERS.
In 1918, in preparation for the expected resumption of " open " warfare, the Germans on the western front adapted the light tninrn- werfer for service as a direct-fire short-range gun of accompaniment for use against undisclosed machine-gun nests and other defem that might be met with in the course of a deep advance. For this purpose the bedplate, already provided with axles, was fitted with higher (29-in.) wheels, and a trail with trail spade was bolted to tl:< small intermediate carriage described above. This trail is pecu- liarly arranged in the forepart. The cross-axle, or through trunnion- bar, which, in the trench-service mounting, connects the ends of the cradle arms to the intermediate carriage, is, in the direct-fire mount- ing, connected to a framework in the trail which can be raised or lowered, thus enabling the cradle and mortar, always supported in front by the elevating screw, to assume either the horizontal or slightly elevated position with trunnion-bar high, or the quasi-vertical loading position (shown by dotted lines) with the trunnion-bar low.
The motion of the framework in question is about a transverse axis contained in the trail and is controlled by a shifting level.
