The zetetic faithful reason about this matter as though the impressions of the senses were trustworthy under all conditions, familiar or otherwise; whereas, in point of fact, we know that the senses often deceive, even under familiar conditions, and almost always deceive under conditions, which are not familiar. A person, for example, accustomed to the mist and haze of our British air, is told by the sense of sight, when he is travelling where a clearer atmosphere prevails, that a mountain forty miles from him is a hill a few miles away. On the other hand, an Italian travelling through the Highlands is impressed with the belief that all the features of the scenery are much larger (because he supposes them much more remote) than they really are. A hundred such instances of deception might easily be cited. The conditions under which the aeronaut observes the earth are certainly less familiar than those under which the Briton views the Alps and Apennines, or the Italian views Ben Lomond or Ben Lawers. It would be rash, therefore, even if no other evidence were available, to reject the faith that the earth is a globe because, as seen from a balloon, it looks like a basin. Indeed, to be strictly logical, the followers of Parallax ought on this account to adopt the faith that the earth is not flat, but basin-shaped, which hitherto they have not been ready to do. We have seen that Parallax describes a certain experiment on the Bedford Level, which, if made as he states, would have shown certainly that something was wrong in the accepted system--for a six-mile straight-edge along water would be as severe a blow to the belief in a round earth, as a straight line on the sea-surface from Queenstown to New York. Another curious experiment adorns his little book, which, if it could be repeated successfully before a dozen trustworthy witnesses, would rather astonish men of science. Having, he says, by certain reasoning--altogether erroneous, but that is a detail--convinced himself that, on the accepted theory, a bullet fired vertically upwards ought to fall far to the west of the place whence it was fired, he carefully fixed an air-gun in a vertical position, and fired forty bullets vertically upwards. All these fell close to the gun--which is not surprising, though it must have made such an experiment rather dangerous; but two fell back into the barrel itself--which certainly was very surprising indeed. One might fairly challenge the most experienced gunner in the world to achieve one such vertical shot in a thousand trials; two in forty bordered on the miraculous.