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286 of the regular, orderly flight, the voice varies, there is a rush of wings, and out of this trouble, as it were, the backward swoop is born. Then the wavering stream—or rather a certain wavering eddy in it—flies on, and again the voice becomes the musical 'har-char, har-char' (a better rendering than 'how-chow'), which characterises the flight out.

"It is as though a sudden surge of thought said 'Back!' and swept some back, but a deeper, stronger surge said 'On!' and on the greater number streamed.

"Again, the stream of flight will sometimes be interrupted by a sort of sweeping or drifting together of a number of the birds, making an eddy in it, as it were—an interruption and perturbation in the current, difficult to describe, and over before one can fix the proper words to it; but indicating some sort of emotion in the birds, a rush of feeling of some kind, something tiresome to note, but which ought to be noted. Once, too, I have seen a single rook flying straight back against the general current of the stream, meeting and passing all the rest on his way to the trees, seeming the very emblem of a fixed intent.

"These curious, pausing, and hesitating movements, in which an idea that seems at first vague becomes, all at once, definite, seem to me to have their origin in what may be termed collective thinking—for this gives a better idea of the appearance of the thing than does the term thought-transference, though that may more correctly indicate the process. The birds do not appear to be influenced by the actions—the external signs of thought—of each other, but numbers