The new guns that were brought forward were innumerable, and many of them, such as the Mersey steel gun, and the great mortar, are still under trial. If this mortar, which is built up of a series of rings 9 inches broad and 3-1/2 inches thick, laid over one another, and fitting tightly, so as to form a barrel, should ultimately prove capable of resisting the full charge of 70 lbs. weight of powder, it will be the most destructive implement yet invented for the purpose of crushing fortified places. In some of the trials which have taken place in the Marshes, it threw its 36-inch shell, weighing 26 cwt., upwards of two miles; and when the missile fell, it buried itself in the ground to so considerable a depth, that after digging down 12 feet, and probing for 15 feet more, it still remained undiscovered. The artillerymen say jestingly that it has dropped down to Australia, No casemate at present in existence could withstand the crushing weight of its fall, and its bursting charge of 200 lbs. of powder. After contemplating this vast establishment for the manufacture of arms, with its sixty steam-engines, which through the agency of upwards of three miles of running shafting, give motion to upwards of a thousand machines, we must not omit to mention the human labour which directs this enormous manufacturing power. During the height of the Crimean war, upwards of 10,000 men and boys were employed in the Arsenal, an army of workers engaged upon the production of the materials of destruction equal to the entire force encamped at Aldershot, and double the number of men that besieged and took Delhi. When such masses of men as this have to be dealt with daily, it is obvious how necessary it must be to possess an organized system by which the loss of what might otherwise be considered mere fractions of time is noted. Let us suppose, for instance, that every man and boy in the Arsenal lost only five minutes per day, and it would amount in the aggregate to the loss of the labour of one man for twelve weeks to the Government.