In addition to the kinds of information which have been described thus far, that the distance senses bring in, there is another kind, fully as important as any in our actual use of our senses; that is information as to the “direction from us” of the object or objects which are arousing the sense. We can get this through all the distance senses, but much more perfectly in the case of sight than in the others. We locate the direction of objects that we smell by turning the head this way and that, sniffing meanwhile, and noting the position in which the odor is caught most clearly. Animals with a keen sense of smell, like dogs, can locate directions very accurately by this means. In the case of hearing the method is to turn the head until the sound is equally loud in both ears. We would expect that a person who was hard of hearing in one ear would never be able to locate sounds by this method; but, as a matter of fact, such persons unconsciously allow for the difference in hearing in the two ears, and so can judge the direction of sounds about as well as any of us. Animals, like horses or rabbits, that have very movable outer ears, undoubtedly can locate sounds much more accurately than we can. Our outer ears are of almost no use in hearing; persons who have had the misfortune to lose them hear practically as well as anyone. [Illustration: DIAGRAM SHOWING HOW DISTANCE AFFECTS THE SIZE OF THE IMAGE] We locate directions with the sense of sight with perfect accuracy, because unless the image of the object we are looking at falls on the center of the retina it is not seen clearly. The only way to make the image fall just there is to look directly at the object. The muscle sense in the eye muscles is extremely delicate, so that if the eyes are rolled at all in looking at anything we know it and can judge, also, how much they are turned from the straight position. In this way we are able to tell exactly the direction from us of any object we can see.