At several points on the shore of Gozo where the attempt of an enemy to land might be possible, the Knights during their early sovereignty improvised a sort of ordnance called an earth mortar, after the following process. A hole of the proper dimensions was cut or drilled in the solid rock, at a certain angle trending towards the shore, designed to hold a hundred pounds of gunpowder. The explosive was placed at the bottom, and after a proper fuse was connected therewith, it was covered with a layer of boards to act as a sort of wadding. Upon the boards a ton or more of stones and rocks were placed, which completed the charge. On the approach of an enemy, which would necessarily be by boats, the fuse could be promptly ignited, and a wild discharge of rocks would at once take place, sending the missiles high into the air at an angle which would drop them upon the approaching enemy. These stones, falling with destructive force upon the boats and upon those who were in them, would scatter death and confusion in their ranks. We have never heard of such a device put in practice elsewhere, but should imagine that it would prove efficacious in a rude way to defend an exposed seacoast. A large or even a small stone descending from a considerable height, under such circumstances, would be sure, if it fell in a boat, to go through its bottom, causing it to fill at once, and would be equally fatal if falling upon the heads or bodies of human beings. The rock, which is of the nature already described, admitted of being easily hewn into such shape as was desired, while exposure to the atmosphere soon hardened it to the required consistency and resisting power. A second discharge of such a mortar might possibly involve as much danger to the defenders as to the enemy. It must be remembered that at this period, between three and four hundred years ago, the use of artillery was comparatively in its infancy, and iron mortars, when they were procurable, were of the crudest manufacture. As forming a contrast to those days, and to the present means of conducting offensive and defensive warfare, it may be appropriate to mention that the author happened to be at Gibraltar not long ago, when a hundred-ton cannon was landed there. With this extraordinary piece of ordnance, it was believed that an effectual shot might be fired across the strait to Africa! As it is at least twenty miles from the Fortress of the Rock to the opposite coast, we took the declaration of the artillerist who expressed this opinion of the power of the gun with considerable allowance.