have spotted it--the new battery of heavy guns that has been annoying us; they were too bold, for once." Sure enough, I thought I made out a thin wisp of smoke trailing among the tree-tops at the south end of the wood. The officer muttered a string of cabalistic instructions into his telephone receiver and motioned me to watch. A minute later, a battery of French heavy guns behind us began their deep, coughing thumps, sending enormous shells hurtling overhead with the pulsing rush of an express train, crescendo and diminuendo. The first shell fell short, showering the trees with earth and débris--the salvos that followed obscured the whole wood in clouds of smoke, broken branches, and dust. Twenty minutes of this before the battery went silent again. A final tremendous explosion, eclipsing all that had gone before, seemed to shake the trees to their roots. "That will hold them for a while," said my friend exultantly, as he telephoned the news back to his battery; "we must have hit their magazine of propelling charges." Next day I was sitting at lunch in our mess, distant about three hundred yards from the observatory, when a series of heavy, racking explosions made the windows rattle. There is a distinct difference between the sound of a gun and that of a bursting shell. The first is a cracking _bang_, or _boum_, as the French say. The latter is a racking, dwelling roar--drawn out, if such a thing can be said of an explosion. Shells were bursting somewhere close to us--many of them. When I went outside I could hear, clear and waspish above the din, the _pinging_ of splinters whizzing overhead, and the occasional crackle of a lopped-off branch. After half an hour of this, a man came panting up with the bad news that the new observatory was completely demolished. There you have the inner workings of siege-war; the Boches, with uncanny craft, knew of the observatory, let the French complete it, and might have let it alone, had it not been instrumental in destroying their battery. That led them into their indiscreet action, for the French, in retaliation, promptly wiped off the map the most important German observatory--an elaborate affair whose exact location they had long known. This time the Boche did not dare retaliate. And so it goes.