The device suggested at the beginning of this paper, claiming to be nothing more than a school room appliance intended to supplement the existing means for giving a knowledge and practice of English to the deaf, employs as its interpreter a different sense from the one universally used. The sense of sight is the sole dependence of the deaf child. Signs, dactylology, speech reading, and the written and printed word are all dependent upon the eye for their value as educational instruments. It is evident that of the two senses, sight and touch, if but one could be employed, the choice of sight as the one best adapted for the greatest number of purposes is an intelligent one; but, as the choice is not limited, the question arises whether, in recognizing the superior adaptability to our purpose of the one, we do not lose sight of a possibly important, though secondary, function in the other. If sight were all-sufficient, there would be no need of a combination. But it cannot be maintained that such is the case. The plan by which we acquire our vernacular is of divine, and not of human, origin, and the senses designed for special purposes are not interchangeable without loss. The theory that the loss of a certain sense is nearly, if not quite, compensated for by increased acuteness of the remaining ones has been exploded. Such a theory accuses, in substance, the Maker of creating something needless, and is repugnant to the conceptions we have of the Supreme Being. When one sense is absent, the remaining senses, in order to equalize the loss, have imposed upon them an unusual amount of activity, from which arises skill and dexterity, and by which the loss of the other sense is in some measure alleviated, but not supplied. No _additional_ power is given to the eye after the loss of the sense of hearing other than it might have acquired with the same amount of practice while both faculties were active. The fact, however, that the senses, in performing their proper functions, are not overtaxed, and are therefore, in cases of emergency, capable of being extended so as to perform, in various degrees, additional service, is one of the wise providences of God, and to this fact is due the possibility of whatever of success is attained in the work of educating the deaf, as well as the blind.