In the more lonely parts of the Reuss the trees were in dense thickets to the water's edge, and the wild ducks fluttered out from them with a splash, and some larger birds like bustards often hovered over the canoe. I think among the flying companions I noticed also the bunting, or "ammer" (from which German word comes our English "yellow hammer"), wood-pigeons, and very beautiful hawks. The herons and kingfishers were here as well, but not so many of them as on the Danube.
Nothing particular occurred, although it was a pleasant morning's work, until we got through the bridge at Imyl, where an inn was high up on the bank. The ostler helped me to carry the boat into the stable, and the landlady audaciously charged me 4_s._ 6_d._ for my first dinner (I always had two dinners on full working days), being pretty sure that she need not expect her customer to stop there again.
The navigation after this began to be more interesting, with gravel banks and big stones to avoid, and a channel to be chosen from among several, and the wire ropes of the ferries stretched tightly across the river requiring to be noticed with proper respect.
You may have observed how difficult it is, sometimes, to see a rope when it is stretched and quite horizontal, or at any rate how hard it is to judge correctly of its distance from your eye. This can be well noticed in walking by the seashore among fishing-boats moored on the beach, when you will sometimes even knock your nose against a taut hawser before you are aware that it is so close.
This is caused by the fact that the mind estimates the distance of an object partly by comparing the two views of its surface obtained by the two eyes respectively, and which views are not quite the same, but differ, just as the two pictures prepared for the stereoscope. Each eye sees a little round one side of the object, and the solid look of the object and its distance are thus before the mind.
Now when the rope is horizontal the eyes do not see round the two sides in this manner, though if the head is leant sideways it will be found that the illusion referred to no longer appears.
Nor is it out of place to inquire thus at length into this matter, for I can assure you that one or two blunt slaps on the head from these ropes across a river make it at least interesting if not pleasant to examine "the reason why." And now we have got the philosophy of the thing, let us leave the ropes behind.