But the advantages of the big gun do not end here. Gunnery, in spite of all its elaboration of checks and controls, is largely a matter of trial and error. All that the checks and controls are designed to do is to reduce the proportion of errors; they cannot by themselves ensure accurate shooting. Accuracy is obtained through correcting the errors by actual observation of the results of shots. This is called “spotting.” When shells are seen to fall too short, or too far, or too much to one side or the other, the error in direction or elevation is at once corrected. But everything depends upon exact meticulous spotting, an almost incredibly difficult matter at the long ranges of modern sea fighting. Imagine oneself looking for the splash of a shell, bursting on contact with the sea ten or more miles away, and estimating just how far that splash is short or over or to one side of the object aimed at. It will be obvious to anyone that the position of a big splash can be gauged more surely than that of a small one, and that the huge splash of the big shell, which sends up a column of water hundreds of feet high, can be seen and placed by spotting officers who would be quite baffled if they were observing shots from 12-inch weapons. In this respect also, that of spotting results, the big gun with its big shell, greatly assists the elimination of inevitable errors and increases the proportion of effective hits to misses. If then we get from bigger guns a higher proportion of hits, and a much greater effectiveness from those hits, then the bigger gun has paid a handsome dividend on its cost and has more than compensated us for the reduction in its numbers. Where the useful limit will be reached one cannot say, nothing but experience in war can decide, but the visible horizon being limited to about fifteen sea miles, there must come a stage in gun expansion when increase in size, accuracy, and destructiveness will cease to compensate for smallness of numbers. And the limit will be more quickly reached when during an action the light does not allow the big gun to use its accuracy at longer ranges to the fullest advantage. * * * * *