The next improvement again came from France, in 1806, when an entirely new set of telegraphs on the following principle was established along the whole extent of the coast of the French empire. A single upright pole was provided with three arms, each movable about an axis at one end--one near the head, the other two at points lower down, all painted black, with their counterpoises white, so as to be invisible a short way off. Each arm could assume six different positions--one straight out on either side of the pole, two at an angle of forty-five degrees above this line, and two at forty-five degrees below it. The arm near the head could be made to exhibit seven positions, the seventh being the vertical; but as this might have been mistaken for part of the pole, it was not employed. The number of combinations or different signals that could be rendered by this machine, employing only three objects, was consequently three hundred and forty-two against sixty-three by that of our Admiralty just described, and which employed six objects. It was not long, however, before we copied the advancement of our neighbours across the Channel, and in some respects improved upon it, the main differences being that only two arms were employed--one at the top, the other half-way down, and that the mast was made to revolve on a vertical axis, so that the arms could be rendered visible from any desired quarter. Its mechanism, the invention of Sir Home Popham, enabled the arms to be moved by means of endless screws worked by iron spindles from below, a vast improvement on the old cords, the more so as they worked inside the mast, which was hollow, hexagonal in section, and framed of six boards bound together by iron hoops, and were thus protected from the weather. Inside the cabin he erected two dials, one for each arm, each having an index finger that worked simultaneously with its corresponding arm above, on the same principle as the little semaphore models to be seen nowadays in our railway signal cabins. We have now described the most prominent of the numerous contrivances which, prior to the application of electricity to that end, were devised and made use of for telegraphic communication, all of which, unlike that subtle power that is not afraid of the dark and can travel in all weathers, possessed a common weakness in their liability to failure through atmospheric causes, fog, mist, and haze. To us who live in this age of electrical marvels, when that particular science more than all others progresses by leaps and bounds, it appears passing strange and almost incredible that so many years were allowed to elapse before the parents of the electric telegraph, the electrical machine and magnetic compass, were joined in wedlock to produce their amazing progeny, which now enables all mankind, however distant, to hold rapid, soft, and easy converse. THE TELEGRAPH OF TO-DAY.