SOUND. IN the character of an appendage, or rider, to the preceding remonstrance, interrogatory, or opening, on my part-for the receipt of intelligence on the subject of light; suppose it were now to be followed by a grave appeal, a solemn lucubration, on the intricacies and phenomena of sound!-The temptation is powerful. As the ignis fatuus the confiding and bewildered traveller, so does the subject, before me, invite, encourage, and hold out strong seductions, to follow with daring, though it be with doubtful step, whithersoever it may propose to lead me. But, no-I am aware of; I dread; and I respect its difficulties. I would lessen them if they lay within the line and demarcation of my means.But-alack!-no more of that. Far, indeed, after this declaration, would I appear from wishing to augment them, when I ruminate, or lucubrate, in the mode of question with myself, or, apply to some person much better qualified to inform me,-on what principle of natural operation it may be, that confined and deeply buried sound is conducted to the ear. By this I mean such sound, as cannot, on account of the circumstances in which it is placed, be conveyed to the organ of hearing by the medium and undulation of air; because it cannot be showed to have any communication therewith, direct or indirect. Sound, that cannot reach atmosphere, cannot possibly find in it a medium of conveyance. Nothing clearer than this-that sound, so conditioned, is heard, might be illustrated by various examples.--Let two-trifling and familiar ones, indeed still they are examples suffice for the occasion. The first, well known to all the world of hearers, in the yet unexplained, though perpetually to be marked occurrence of the cracking within the structure of a joint, such as that of the finger, ankle, &c. &c. whence egress, from the burial place of sound, to the nimble air without, is rendered so impossible, that, to dispute the fact, or as a dernier ressort, to talk of any vibration of the substance, integuments, &c. &c. of the parts, might fairly be accounted the subterfuge of embarrassment; an evasion of the question;-the second, known to all the world of philosophers, as often as they hear the guinea fall, or listen, with success, to a little musical instrument, suspended, and piping in vacuo; at least in a perfectly exhausted receiver; where sound, thus isolated, thus totally severed from all communication, from all contact with circumambient air, cannot, I presume, by the medium of a fluid which it cannot reach through the agency of any other fluid, or of substance, be possibly conveyed, and rendered audible, by vibrations, and undulations, which it has no power of inciting. |