This ignorance, however, is not altogether miserable. Out of it we get the constant pleasure of discovery. Every fact of nature comes to us each spring, if only we are sufficiently ignorant, with the dew still on it. If we have lived half a lifetime without having ever seen a cuckoo, and know it only as a wandering voice, we are all the more delighted at the spectacle of its runaway flight as it hurries from wood to wood conscious of its crimes and at the way in which it halts hawk-like in the wind, its long tail quivering, before it dares descend on a hill-side of fir-trees where avenging presences may lurk. It would be absurd to pretend that the naturalist does not also find pleasure in observing the life of the birds, but his is a steady pleasure, almost a sober and plodding occupation, compared to the morning enthusiasm of the man who sees a cuckoo for the first time, and, behold, the world is made new.And, as to that, the happiness even of the naturalist depends in some measure upon his ignorance, which still leaves him new worlds of this kind to conquer. He may have reached the very Z of knowledge in the books, but he still feels half ignorant until he has confirmed each bright particular with his eyes.