_Possibility of a Sense that shall meet these Limitations._--We can conceive of a sense that should differ in both these respects--that should take cognizance of distant objects, not capable perhaps of being brought into contact--and that should also operate analytically, or work from a given whole to the parts, and not from the parts to a whole, thus giving us possession at once of a complete object or series of objects. Such a sense, it is easy to see, would possess decided advantages, and in connection with the one already considered, would seem to bring within the sphere of our cognizance almost the complete range of external nature. This we have, and this exactly, in the sense of _vision_. It takes in objects at a distance, and takes in the whole at a glance. _This new Sense still limited._--This new sense, however convenient and useful as it is, has evidently its limitations. It is available only through a given medium, the light. Strictly speaking, it is the light only that we see, and not the distant object; that is known indirectly by means of the light that variously modified, travels from it to the eye. When this fails, as it does during several hours of the twenty-four, or when it is intercepted by objects coming between and shutting out the forms on which the eye seeks in vain to rest, then our knowledge from this source is cut off. _Still another Sense desirable._--Under these circumstances, might it not be well, were there given an additional sense, of the same general nature and design, but operating through a different medium, sure to be present wherever animal life exists, so that even in the darkness of the night, or the gloom of the dungeon, we might still have means of knowing something of the surrounding objects. And what of this medium, or avenue of sense, were of such a nature as to be capable of modification, and control, to some extent, on our part, and at our pleasure, so as to form a means of voluntary communication with our fellow-beings. Would not such an arrangement be of great service? Exactly these things are wanted; exactly these wants are met, and these objects accomplished, by a new sense answering to these conditions--the sense of _hearing_--the cognizance of sound. This we produce when we please by the spoken word, the vocal utterance, whether of speech, or musical note, or inarticulate cry, varied as we please, high, low, loud, soft--a complete alphabet of expression, conveying thus by signals, at once rapid and significant, the varying moods and phases of our inner life to other beings that had else been strangers, for the most part, to the thoughts and feelings which agitate our bosoms.