The relationship between light and sound does not terminate in the fact, of itself sufficiently striking, that they both obey similar conditions of transmission and reflection. True, they each pass to the human organ, not by one unbroken leap, but by a series of waves. Literally, lightning no more darts upon the eye than the faintest beam of dawn; thunder comes undulating to the ear as truly as the softest sigh; and the light cast upon us from a mirror is only an echo through ether instead of air.
But there is a far more intricate affiliation between them. In the very possibilities of their existence they are the same. Every ray of light can be comprehended within the range of seven radical colors and the combinations of them. This law of but seven possible colors is not an accident, but a primeval and necessary accompaniment of the manner of transmission.
Every possible sound likewise lies between the two termini of a gamut whose number of root sounds is seven, and this septenary law of sound is as necessary as that of light.
The universality with which these laws are practically known by means of the prism and the octave, take off, as is the case in so many other habitual mysteries, the edge of our legitimate wonder. Yet when, for a moment, we reflect calmly upon the fact that we may analyze light of any possible kind with the most rigid scrutiny without adding a single principal color to a fixed range of seven; that we may utter any conceivable sound without escaping from the same mystic boundaries; that in both cases our only changes must be rung by reduplication or blending within those adamantine gamut walls; when we reflect, I say, on these two truths, each fit food in itself for wonder, and find that in fact they are but one truth, and that a characteristic of sensations which we have always treated as essentially different, we shall have reason to confess, with amazement, a far more intimate union between sight and hearing than any of outer coincidence. Indeed, excepting the before-mentioned difference, which their several media of travel impress upon them, philosophy can not find a mark of distinction between sight and sound.
How strong a claim to interior oneness this law of seven bestows can be fully felt only by realizing how essential a law it is. So essential is it that probably, in the whole universe, it may be impossible to find a complete range of any operations which does not, in its internal nature, submit to it. I say this perfectly aware that there are insuperable obstacles, while we enjoy no more than our present development of mind, to proving this to a logical certainty. Yet the vast probability which appears to me in the proposition rests upon one fact which I have never seen noticed in connection with these senses. Doubtless it has been noticed, however, for from time immemorial the significancy of the number seven has employed the researches of philosophers and theologians. The fact is this: In the Divine philosophy of Creation, which is, at the same time, the most reverend also for age, there is a stress laid upon the importance of this number as exponent of some law of completion, of perfectness, which, unless it be granted deeply significant, can be treated upon no middle ground between that and a puerility partaking of imposture. The seventh day as the one whose advent expressly witnessed the completion of the Kosmos (whatever of length we may give to the days of the creation); the impress of some secret import upon seven, by countless ceremonial symbols, inculcated to that people who, during the whole period of the Theocracy, held more direct communion with the Divine source of all Truth than any nation before or since; the constant recurrence, in the Word, of prophetic uses of the number, and such a phrase as this: “Wisdom hath builded her house; she hath hewn out her seven pillars:” all these seem to indicate, beyond the possibility, in my mind at least, of conceiving the contrary possible, that this number is a fundamental law of perfectness in the Universe.
As such, therefore, and comprehending under its rule the two senses of sight and hearing, it proves a oneness in their essential conditions which seems irrefutable. In some of the more intensely awakened hashish states, there was a great light thrown upon this subject, but, with many other views gained like it, through symbolization, on my return to the natural state it passed away from my mind forever.
4. Smell. Within the last ten years an attempt has been made by some Frenchman of speculative mind, whose name I forget, to determine if this sense a septenary gamut also, in which the only two tones that have not escaped me, to the best of my knowledge, were citron and rose. If the natural existence of such a gamut could be accurately determined, it would be a great auxiliary, certainly, to our argument; but I fear that our knowledge of the catalogue and relations of all possible odors is so very imperfect as to make the research only a fanciful recreation. From the great variety of the objects, and the lack of scientific delicacy of the sense of smell, it is a very difficult one to deal with. He who investigates it through its own instrumentality, which, of course, is the only possible method for an inductive science, is very much at the disadvantage of him who should try to dissect an animalcule with his finger nail.
Yet there is, even with such obstacles in the way, a possibility of proving odor ultimately resolvable into that force which we have discovered as the common idea of the preceding senses. I have held the opinion, whether
