I took my way up the back of the hill and stole through the wood, carefully keeping a watchful look out all round me, for I feared the presence of either of the sets of spies. At the very top I came upon a good sized circle of masonry, low but heavily built of massive stones completely covered with rich green lichen. The circle was some fifteen feet diameter, and the top was slightly arched as though forming a roof. Leaning over it I could hear a faint trickle of water; this was evidently the source of the castle supply.
I walked round it, examining it carefully; anything which had any direct communication with the castle was at present of possibly the supremest importance. There was no flaw or opening anywhere; and from the unbroken covering of the stones by the lichen, it was apparent that there had been no disturbance for years.
I sat down on the edge of the stonework and for a long time thought over matters of probability. If underneath me, as was almost to be taken for granted, lay the reservoir of the castle, it must have been made coevally with Crom itself, or even with the older castle on whose ruins it was built. It must be fed by springs in the rock which formed the base of the hill and cropped out all over it; and if it was not approachable from without, there must be some way of reaching the water from within. It might be that the chamber which contained the reservoir had some other entrance from the hill top, or from some lower level. Accordingly I made as I conceived a bee line for the castle, till I came to the very base of the hill, for I knew that in matters of water conduit the direct way is always chosen where work has to be done. As I went, I conned the ground carefully; not merely the surface for that was an uniform thick coating of brown pine needles, but the general conformation. Where a trench has been made, there is ever after some trace of it to be found. Even if the workmen level the trench most carefully there and then, the percolation of rain through the softer broken earth will make discovery of the change by shrinkage. Here, however, there was no such sign; the ground, so far as one could judge, had never been opened. The trees grew irregularly, and there was no gap such as would be, had one ever been removed. Here and there particles of rock cropped out amongst the pine needles just as anywhere else. If any opening existed it was not on the direct line between the reservoir and the castle.
Back again I went to the reservoir, and, using it as a base, began to cast around for some opening or sign. I made circles in all directions, just as a retriever does when looking for a fallen partridge in a dry stubble when the scent is killed by heat.
At last I came upon something, though whether or no it might have any point of contact with my purpose, I could not at once decide. It was a rude monument of some kind, a boulder placed endwise on a slab of rock roughly hewn to form a sort of square plinth. This again was surrounded on the outside, for the whole monument was on the very edge of a steeply-dipping crag, by a few tiers of rough masonry. The stones were roughly cut and laid together without mortar; or if mortar or cement there had ever been, time and weather had washed it away. In one respect this structure was in contrast to that above the reservoir, there was not a sign of moss or lichen about it. The trees of the wood came close up behind it; in front it was shut out from view below by the branches of a few pine trees which grew crookedly from a precarious foothold amongst the ledges of rock beneath. As I stood in front of it, I could see nothing immediately below me; however, when I had scrambled to a ledge a few feet lower down, the back wall of the old chapel became visible, though partly obscured by trunks and branches of intervening trees. I searched all over the monument for some inscription, but could see none. Then I stood on the plinth to see if there might be any inscription on the top of the boulder. As I stood, looking over the top of it from the bank, I could just see through a natural alleyway amongst the tree tops, the top of one corner of the castle, that on the side of, and farthest from the old chapel. As I looked, a bright thought struck me. Here was a place from which one might correspond with the castle, unseen by any one save at the one spot. I determined then and there, that Marjory and I should arrange some method of signalling to one another.
Somehow this place impressed me, possibly because it was the only thing, except the reservoir, which seemed to have a purpose in the whole scheme of the hill top. Where there was labour and manifest purpose, there must surely be some connection. I examined all round the place minutely, scrambling down the rocks below and on either side, but always keeping a bright look out in case of spies. The only thing I noticed was that there seemed a trace of some kind of a pathway through the wood here. It was not sufficiently marked to allow one to accept it with certainty as a pathway; but there is something about a place which is even occasionally trodden, which marks it from its surroundings virgin of footsteps. I could not find where the path ended or where it began. It seemed to grow from the monument, but here underfoot was stone and hard gravel; and the wind coming over the steep slope swept the fallen pine needles back amongst the shelter of the trees. After a few hundred yards any suggestion of a pathway disappeared, lost in the aisles of the pine trees spreading round on every side. There was no need of a pathway here where all was open. Once or twice as I searched the thought came to me that there might be some opening here to a secret way or hiding place; but look how I would, I could not find the faintest trace or suggestion of any opening. In the end I had to take it that the erection was merely a monument or mark of some kind, whose original purpose was probably lost in time.
At last, as the day was well on, I made my way back to where my bicycle was hidden, always taking care to keep from observation. Then emerging on the road, I went as usual through the old ruined gateway and the long winding avenue to the castle.
Marjory met me with an anxious look, and hung on to my arm lovingly as she said:
“Oh, you are late! I have been quite nervous all the morning lest anything should have happened to you!” Mrs. Jack, after we had greeted, discreetly left us alone; and I told my wife of all that I had thought since we had parted, and of what I had seen on the hill top. She was delighted at the idea of a means of signalling; and insisted on my coming at once to the roof to make further arrangements and discoveries.
We found the spot which I had indicated admirably adapted for our purpose. One could sit on the stone roof, well back from the wall, and through one of the openings in the castellation see the top of the monument amongst the tree tops; and could yet be unobserved oneself from any other spot around. The angles of the castellation of the various walls shut out the tops of the other hills or mounds on every side. As the signs of our code were already complete we had only to fix on some means of signalling ‘A’ and ‘B’. This we did by deciding that by daylight A should be signified by red and B by white and at night A by red and B by green. Thus by daylight two pocket handkerchiefs of red and white or two flowers of white and red; or a piece of paper and a red leaf or flower would suffice. We fixed on colour as the best representative, as the distance made simplicity necessary. By night an ordinary bicycle lamp with the lens covered could be used; the ordinary red and green side lights could be shown as required. Then and there we arranged that that very afternoon when I had left the castle I should steal back to the monument and we should make a trial of our signalling.