That enormous engine, Mallet’s monster mortar, of which I give an engraving on page 100, clearly proves this to be the case. It will be observed to be constructed with a solid cast iron breech end, the dimensions of which will be seen by referring to the engraving. Abutting upon this are a succession of wrought iron hoops, ingeniously inserted into each other, and more firmly secured by six outside staves of great dimensions, which, at the muzzle ring, pass through openings in the muzzle ring, with heads like enormous rivets. The binding power is given by “quoin-like” wedges, driven through the opposite end of the stave, beneath the projection of the cast breech, giving power to tighten the longitudinal binders by a blow when required. [Illustration: Mallet’s Mortar.] DIMENSIONS. Tons. cwt. qrs. lbs. Cast iron base with wrought iron breech shrunk into bore 21 19 0 2 Wood carriage complete, with wrought iron screw and spanner for elevating mortar 8 8 0 14 Bottom part of mortar to fit on top of the breech 7 5 3 23 Part of mortar (a ring) to fit on the top of the above 5 8 3 23 Do. do. do. 3 0 2 13 Muzzle ring 1 2 3 12 Wood ring 0 0 1 0 Wrought iron ring 0 4 3 4 Wrought iron conical ring to fix on top of muzzle ring 0 3 3 25 T-headed bolts, with gibs and keys for fixing mortar to base: may be called outer staves 1 16 2 0 Wood-wedges, &c., for elevating 0 13 3 22 Outer pin, with cross for turning mortar round 0 8 3 14 ------------------ Total weight 50 13 2 21 Weight of shell unfilled, 26 cwt. 2 qrs.; diameter, 36 inches. This is notorious as a monster failure, even with a charge of powder amounting to only one half what the projector fondly hoped would be perfectly harmless in its effects. This Brobdignagian toy has proved to be fearfully expensive, the cost having been estimated at eight thousand pounds. It has, I believe, been the largest and most expensive experiment indulged in by the noble “projector,”[6] and I sincerely hope it will be the last. [6] Lord Palmerston.