Flocks of starlings have a way of flying which is peculiar to them, and seem to move according to a regular and uniform plan such as that of a well-drilled company of soldiers punctiliously obeying the orders of their one and only leader. The starlings obey the voice of instinct, and their instinct tells them to keep on approaching the centre of the main body, whereas the rapidity of their flight takes them incessantly beyond it; so that this multitude of birds, this joined in their common movement towards the same magnetic point, incessantly coming and going, circling and criss-crossing in all directions, forms a kind of highly turbulent eddy, the entire mass of which, though not moving in any definable direction, seems to have a general tendency to turn in upon itself, this tendency resulting from the individual circling movements of each one of its parts, in which the centre, endlessly tending to expand but continually pressed down and repulsed by the opposing force of the surrounding lines which weigh down on it, is constantly tighter, more compact, than any one of these lines which themselves become more and more so, the nearer they come to the centre. In spite of this strange way of eddying, the starlings nonetheless cleave the ambient air with rare speed and every second perceptibly gain precious ground as they move towards the end of their weary migration and the goal of their pilgrimage.