By the assistance of the guide, however, who proved a steady and useful assistant, I managed to set the instrument up within a couple of feet of the "termination rock" as it is called, which is at the distance of 153 feet from the side of the waterfall measured horizontally along the top of the bank of shingle. This measurement, it is right to mention, was made a few days afterward by Mr. Edward Deas-Thompson of London, the guide, and myself with a graduated tape.
While the guide held the instrument firmly down, which required nearly all his force, I contrived to adjust it, so that the spirit level on the top indicated that the tube was in the perpendicular position. It would have been utterly useless to have attempted any observation without this contrivance. I then secured all tight, unscrewed the bag, and allowed the mercury to subside; but it was many minutes before I could obtain even a tolerable reading, for the water flowed over my brows like a thick veil, threatening to wash the whole affair, philosophers and all, into the basin below. I managed, however, after some minutes' delay to make a shelf or spout with my hand, which served to carry the water clear of that part of the instrument which I wished to look at and also to leave my eyes comparatively free. I now satisfied myself by repeated trials that the surface of the mercurial column did not rise higher than 29.72. It was sometimes at 29.70 and may have vibrated two or three hundredths of an inch. This station was about 10 or 12 feet lower than the external ones and therefore I should have expected a slight rise in the mercury; but I do not pretend to have read off the scale to any great nicety, though I feel quite confident of having succeeded in ascertaining that there was no sensible difference between the elasticity of the air at the station on the outside of the Falls and that, 153 feet within them.
I now put the instrument up and having walked back towards the mouth of this wonderful cave about 30 feet, tried the experiment again. The mercury stood now at 29.68, or at 29.70 as near as I could observe it. On coming again into the open air I took the barometer to one of the first stations, but was much disappointed though I cannot say surprised to observe it full of air and water and consequently for the time quite destroyed.
My only surprise, indeed, was that under such circumstances the air and water were not sooner forced in. But I have no doubt that the two experiments on the outside as well as the two within the sheet of water were made by the instrument when it was in a correct state: though I do not deny that it would have been more satisfactory to have verified this by repeating the observations at the first station.
The American Fall.
From a photograph by Notman, Montreal.
On mentioning these results to the contending parties in the controversy, both asked me the same question, "How then do you account for the difficulty in breathing which all persons experience who go behind the sheet of water?" To which I replied: "That if any one were exposed to the spouts of half a dozen fire engines playing full in his face at the distance of a few yards, his respiration could not be quite free, and for my part I conceived that this rough discipline would be equally comfortable in other respects and not more embarrassing to the lungs than the action of the blast and falling water behind this amazing cataract."
It is almost impossible to conceive of the immense mass of water tumbling over this precipice. It has been estimated in tons, cubic feet, and horse-power, but the figures are so large as to stagger the human mind. Out there at the apex of the angle, the water, over twenty feet deep, is drawn from almost half a continent, forming a picture to make one's nerves thrill with awe and delight, where the international boundary line swings back and forth as the apex of the angle formed sways from side to side.
Just off the shore of the island are seen Terrapin Rocks. Why this name was applied is uncertain. These rocks are scattered in the flood to the very brink of the fall and in the titanic struggle with the rush of waters seem hardly able to maintain their position. Upon these rocks on the very brink of the Falls in 1833 was erected, by Judge Porter, Terrapin Tower, for many years one of the centres visited by every person journeying to the Falls. From its summit could be seen the wild rapids rushing on toward the precipice; below shimmering green of the fall. Down, far down, in the depths beneath was the boiling, seething caldron, from which arose beautiful columns of spray. From this position, forty-five feet above the surface of the water, probably a more comprehensive view of the many features of Niagara could be obtained than from any other point. Forty years later it was blown up, not because it was unsafe, as alleged, but that it might not prove a rival attraction to Prospect Point. Recently suggestions have been made looking toward the restoration of this ancient landmark, but no definite action has been taken.