By this time the founding of guns in cast iron had made progress. Cast iron was cheap, and of a greater hardness and endurance than bronze, but more like to crack and fly and endanger the crew, and requiring an enormous expenditure of wood-charcoal for its production. The use of mineral coal for iron smelting was not discovered until the following century, and even then, because of the opposition of the vested interests, it was long before it displaced the use of timber. In the Tudor times the iron and brass foundries were nearly all in the wooded south of England. The rivers of Sussex and Kent had for centuries been dammed to form hammer-ponds, and the sound of the tilt-hammers was heard throughout these counties. To such an extent were the forests depleted of wood to form fuel for the Wealden foundries, that serious inroads were made on the available supplies of shipbuilding timber; legislation was required in Elizabeth’s reign to prevent the charcoal-burner from robbing the shipwright of his raw material. Gun-founding, even in bronze, was still a somewhat primitive art. But, once taught, the English founders soon excelled their teachers; and Norton’s eulogy, and the records of foreign efforts to obtain possession of English pieces, bear witness to the superiority of our workmen. The products of the most famous founders of that time in Europe were very imperfect. “Some of their pieces (and not a few) are bored awry, their soul not lying in the midst of the body of metal; some are crooked in their chase, others of unequal bores, some too light towards the breech turn their mouths downwards in their discharge, and so endanger their own vawmures and defences; others are too heavy also in their breach, by placing the trunnions too much afterwards, that coynes can hardly be drawn.... Some are come forth of the furnace spongey, or full of honeycombs and flaws, by reason that the metal runneth not fine, or that the moulds are not thoroughly dryed, or well nealed.... Yet thus much I dare say to the due commendations of our English gunfounders, that the ordnance which they of late years have cast, as well for neatness, as also for reasonable bestowing and disposing of the metal, they have far excelled all the former and foreign aforementioned founders.” Norton, a land gunner, was here referring to brass ordnance, alone used on shore.