Thought-Culture; Or, Practical Mental Training. Atkinson William Walker

giving the whole attention to the particular speaker; or, in the same manner, selecting one singer in a church choir or band of singers; or one musical instrument in an orchestra; or one piece of machinery making sounds in a room filled with various machines, etc. The practice of so doing is held to strengthen one's powers of concentration and attention.

      Draper says: "Although many images may be simultaneously existing upon the retina, the mind possesses the power of singling out any one of them and fastening attention upon it, just as among a number of musical instruments simultaneously played, one, and that perhaps the feeblest, may be selected and its notes exclusively followed." And as Taylor says: "In a concert of several voices, the voices being of nearly equal intensity, regarded merely as organic impressions on the auditory nerve, we select one, and at will we lift out and disjoin it from the general volume of sound; we shut off the other voices – five, ten and more – and follow this one alone. When we have done so for a time, we freely cast it off and take up another." Carpenter says: "The more completely the mental energy can be brought into one focus and all distracting objects excluded, the more powerful will be the volitional effort."