The gunner's appreciation of these things is usually keener even than one's own. One day when reconnoitring for an O.P. with a couple of telephonists, I came upon a house that had once been used for the purpose, but out of which its occupants had been driven by heavy shell-fire. The interior of the place presented an indescribable appearance. Its original owners had fled early in the war, leaving everything as it stood, and a succession of inquisitive searchers had been all through it to see if they could find anything of value. Dresses, broken bottles, letters, rags of all descriptions, a sewing machine, blended with the plaster from the walls and clay from the burst sandbags. Very little of the roof was left, and heavy rain had made of this mass a peculiarly evil-smelling mud, from which protruded here and there lumps of bread, bully-beef and cheese, whose increasing age was apparent. Some sort of cesspit had burst and flooded the cellar, which had been used as a dug-out, and in the centre of the savoury flood floated a mattress that looked as if it held the germs of all the plagues of Egypt. Outside, shrapnel were bursting freely, I fancy the enemy had seen us enter the place. I overheard one of my telephonists apostrophizing it: "You're a nice 'ouse, you are," he said. "Blowed if I don't advertise yer in the bloomin' papers, 'Charming bijou residence, quiet 'ealthy situation, perfect repair, hevery convenience, pleasant garden.' I _don't_ think!" III OBSERVATION It has been said in a previous chapter that the fire of any given battery is, in the majority of cases, directed by an officer in an observation post from whence he can see the target and the ground surrounding it. The general principles of this observation are as follows. The position of the battery and target are ascertained upon a map, and by means of it the range and direction of the target from the battery are obtained. A calculation based upon this information is made, and a certain elevation and direction given to the guns. A round is then fired, and the position of the point where it falls relative to the target noted by the observation officer, who gives a correction based upon the error. This correction is transmitted to the battery by methods depending on the distance between it and the observation post, but almost invariably by telephone, and applied to the guns. Another round is then fired, which is again observed and a fresh correction made as before. This process continues until the rounds are falling at or very close to the target. It sounds remarkably simple, but is in practice extremely difficult. To hit an unknown target with the expenditure of the minimum possible number of rounds requires considerable experience in observation, for the puff of a bursting shell lasts only for the fraction of a second, and is apt to look very small at a distance of more than a few hundred yards. Further, knowledge of the vagaries of each individual gun is required, and