Scientific Culture, and Other Essays / Second Edition; with Additions

THE SPIRITUAL LIFE. [Q]

We have reached the end of our long journey, and now we are ready to turn back and start for home.

The Reis is at his helm, the great sail is furled and bound closely to the long yard; for, as the wind during the early spring blows here constantly from the north, we must depend on the rapid current of the Nile to bear us back to civilization: a river which, flowing through so many generations of men from the unknown to the unlimited, not unfitly typifies the course of history; and as, in imagination, we drift with this historical stream, we can not fail to learn the lesson which the associations and the scenes are so calculated to teach. That lesson is the grandeur, the glory, and the immortality of the spiritual life of man.

We go back six thousand years, and find the Sphinx, as to-day, looking toward the rising sun, and pondering the problem of human destiny.

The pyramid-builders come, and erect those neighboring piles to preserve their bodies when dead for that glorious destiny in which they trust.

The long procession of the Pharaohs passes, and each inscribes indelibly on rocky walls his faith in the great God who holds human destiny in his hands.

Moses comes, and leads out of Egypt the chosen people to prepare the way for the expected Messiah.

The Assyrians and the Persians come, and, while seeking to read their destiny in the courses of the stars, pay homage to the same great hope.

The Greeks come, and, even amid gross licentiousness and idolatry, erect magnificent temples, in attestation of a belief in human destiny which, however degraded, still survived.

The Romans come, and in this mystic land lay aside their legal codes, and add their testimony to the same great truth.

The Christian hermits come, and make the storied stones of the Pharaohs re-echo with their triumphant songs.

The Arab comes, and, as morning and evening he gazes into the East, sees visions of the glorious Mecca of his hopes for which the Sphinx has looked so long.

Last of all, the modern traveler comes, and he journeys in vain if he does not recognize in all this aspiration and all this yearning the attestation of those spiritual truths which to him the risen Christ has revealed.

As in material nature every unemployed organ distinctly points to a previous use or to a future fruition: so, in the spiritual world, every striving is a promise of a possible good; and these yearnings of humanity, which have come down through the ages, are as truly a promise of the Eternal as were the words spoken to Abraham on the plains of Mamre.

Coming home from the East, we can not fail to see, more clearly than before, how artificial are most of the conventionalities of our modern civilization, and how greatly such cares of the world tend to obscure the great distinction between the spiritual and the material which is ever present to Oriental thought; and this is especially true in our own country, where the demands of material nature are so pressing, and where the physical wants, which our highly artificial life entails, so completely engross the attention of us all.

It is well to go away at times, that we may see another aspect of human life, which still survives in the East, and to feel that influence which led even the Christ into the wilderness to prepare for the struggle with the animal nature of man.

We need something of the experience of the anchorites of Egypt to impress us with the great truth that the distinction between the spiritual and the material remains broad and clear, even if with the scalpel of our modern philosophy we can not completely dissect the two; and this experience will give us courage to cherish our aspirations, keep bright our hopes, and hold fast our Christian faith until the consummation comes.

My young friends, there are many who will tell you that the Sphinx has merely propounded a riddle to the ages; and that the yearnings of your young lives—like those of the early Egyptians, who set up this memorial of their hopes—are merely a delusion and a snare.

Do not believe in any such pessimism.

It is merely the dying gasp of your animal nature! But give your utmost efforts that these aspirations be not smothered by the cares and trials which must come to you as they come to all.

Have faith in the Eternal who implanted those cravings in your nature; and remember that all knowledge rests on the assurance that the Eternal can not be false. Be loyal to the truth of that witness in your hearts, and advancing years will only bring you increased reliance on the promises he ever whispers to those who trust him; and he will certainly lead you, at last—as he has led the faithful in all ages—into the clear light of the perfect day.

My fellow-students, if these fleeting pictures of scenes which have given me fresh courage, shall aid any of you in the conflict of life, my object in these lectures will be gained, and however incongruous with the associations of physical science such scenes may have appeared, you will bear me witness that the great lesson they teach has constantly been enforced in this place. The spiritual life of man recognizes its exalted intellectual likeness in the life of Nature, and it is this vision of the Omniscient which distinguishes and ennobles mental culture, whether it be in the fields of science, of literature, or of art.

THE END.

FOOTNOTES:

[A] As some of the readers of this volume may be interested to compare these values, we reproduce the "Table of Molecular Data" from Professor Clerk Maxwell's lecture on "Molecules," delivered before the British Association at Bradford, and published in "Nature," September 25, 1873.

Molecular Magnitudes at Standard Temperature and Pressure, 0° C. and 76 c. m.

RANK ACCORDING TO ACCURACY OF KNOWLEDGE.	Hydrogen.	Oxygen.	Carbonic Oxide.	Carbonic Dioxide.
Rank I.
Relative mass	1	16	14	22
Velocity in metres per second	1,859	465	497	396
Rank II.
Mean path in ten billionths (10^-10) of a metre	965	560	482	379
Collisions each second—number of millions	17,750	7,646	9,489	9,720
Rank III.
Diameter in hundred billionths (10^-11) of a metre	58	76	83	93
Mass in ten million million million millionths (10^-25) of a gramme	46	736	644	1,012

Number of molecules in one cubic centimetre of every gas is nineteen million million million on 19 (10¹⁸).

Two million hydrogen molecules side by side measure a little over one millimetre.

[B] See Professor Maxwell's lecture, loc. cit.; also, Appletons' "CyclopÆdia," article "Molecules."

[C] There is an obvious distinction between the free and the disturbed path of a molecule, and we can not overlook in our calculations the perturbations which the collisions necessarily entail. Such considerations greatly complicate the problem, which is far more difficult than would appear from the superficial view of the subject that can alone be given in a popular lecture.

[D] See notice of these investigations by the author of this article, in "American Journal of Science and Arts," September, 1877 (3), xiv, 231.

[E] The reader will, of course, distinguish between the differential action on the opposite faces of the vanes of the radiometer and the reaction between the vanes and the glass which are the heater and the cooler of the little engine. Nor will it be necessary to remind any student that a popular view of such a complex subject must be necessarily partial. In the present case we not only meet with the usual difficulties in this respect, but, moreover, the principles of molecular mechanics have not been so fully developed as to preclude important differences of opinion between equally competent authorities in regard to the details of the theory. To avoid misapprehension, we may here add that, in order to obtain in the radiometer a reaction between the heater and the cooler, it is not necessary that the space between them should actually be crossed by the moving molecules. It is only necessary that the momentum should be transferred across the space, and tide may take place along lines consisting of many molecules each. The theory, however, shows that such a transfer can only take place in a highly rarefied medium. In an atmosphere of ordinary density, the accession of heat which the vanes of a radiometer might receive from a radiant source would be diffused through the mass of the inclosed air. This amounts to saying that the momentum would be so diffused, and hence, under such circumstances, the molecular motion would not determine any reaction between the vanes and the glass envelope. Indeed, a dense mass of gas presents to the conduction of heat, which represents momentum, a wall far more impenetrable than the surrounding glass, and the diffusion of heat is almost wholly brought about by convection currents which rise from the heated surfaces. It will thus be seen that the great non-conducting power of air comes into play to prevent not only the transfer of momentum from the vanes to the glass, but also, almost entirely, any direct transfer to the surrounding mass of gas. Hence, as stated above, the heated molecules bound back and forth on the vanes without change of condition, and the mass of the air retains its uniform tension in all parts of the bulb, except in so far as this is slowly altered by the convection currents just referred to. As the atmosphere, however, becomes less dense, the diffusion of heat by convection diminishes, and that by molecular motion (conduction) increases until the last greatly predominates. When, now, the exhaustion reaches so great a degree that the heat, or momentum, is rapidly transferred from the heater to the cooler by an exaggeration, or, possibly, a modification, of the mode of action we call conduction, then we have the reaction on which the motion of the radiometer wheel depends.

[F] "Nature," No. 22, March 31, 1870.

[G]

For example, the native crystals of sulphur have	a : b : c = 1 : 2·340 : 1·233.
Crystals of gypsum have	a : b : c = 1 : 0·413 : 0·691.
Crystals of tin-stone have	a : b : c = 1 : 1 : 0·6724.
And crystals of common salt have	a : b : c = 1 : 1 : 1.

[H] The origin of the axes is always taken as the center of the sphere of projection.

[I] "Obituary Notices from the Proceedings of the Royal Society," No. 206, 1880, to which the writer has been indebted for several biographical details.

[J] This notice is reprinted from the Proceedings of the American Academy of Arts and Sciences, vol. xviii, 1882-'83.

[K] Reprinted from the Proceedings of the American Academy of Arts and Sciences, vol. xix, 1883-'84.

[L] A. W. Hofmann, in "Nature," February 6, 1880, to whose admirable and extended biography the writer is indebted for much of the material with which this notice has been prepared.

[M] Hofmann, loc. cit.

[N] Remarks made at the dinner of the Harvard Club of Rhode Island, Newport, August 25, 1883.

[O] This article was written and read to the Faculty of Harvard College shortly after Lord Coleridge's visit to the United States, in the autumn of 1883.

[P] An address delivered at the opening of the Summer School of Chemistry at Harvard College, July 7, 1884.

[Q] An Address to College Students at the close of a course of lectures on Egypt and her Monuments. Illustrated by lantern photographs.

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