may or may not be known. The very nature of force or energy is not understood. In the language of Spencer, "By the persistence of force, we really mean the persistence of some cause which transcends our knowledge and conception."[A]

[Footnote A: First Principles, Spencer, 4th ed., p. 200.]

It need hardly be explained that energy cannot exist independently of matter; and that the law of the persistence of matter is necessary for the existence of the law of persistence of force.

[Sidenote: Universal intelligence, comparable to universal energy is indestructible, according to Joseph Smith.]

Joseph Smith was not a scientist; and he made no pretense of solving the scientific questions of this day. The discussion relative to the convertibility of various forms of energy was in all probability not known to him. Still, in his writings is found a doctrine which in all respects resembles that of the conservation of energy.

Joseph Smith taught, and the Church now teaches, that all space is filled with a subtle, though material substance of wonderful properties, by which all natural phenomena are controlled. This substance is known as the Holy Spirit. Its most important characteristic is intelligence. "Its inherent properties embrace all the attributes of intelligence."[A] The property of intelligence is to the Holy Spirit what energy is to the gross material of our senses.

[Footnote A: Key to Theology, P. P. Pratt, 5th ed., p. 40.]

In one of the generally accepted works of the Church, the energy of nature is actually said to be the workings of the Holy Spirit. The passage reads as follows: "Man observes a universal energy in nature—organization and disorganization succeed each other—the thunders roll through the heavens; the earth trembles and becomes broken by earthquakes; fires consume cities and forests; the waters accumulate, flow over their usual bounds, and cause destruction of life and property; the worlds perform their revolutions in space with a velocity and power incomprehensible to man, and he, covered with a veil of darkness, calls this universal energy, God, when it is the workings of his Spirit, the obedient agent of his power, the wonder-working and life-giving principle in all nature."[A]

[Footnote A: Compendium, Richards and Little, 3rd ed., p. 150.]

In short, the writings of the Church clearly indicate that the various forces of nature, the energy of nature, are only manifestations of the great, pervading force of intelligence. We do not understand the real nature of intelligence any better than we understand the true nature of energy. We only know that by energy or intelligence gross matter is brought within reach of our senses.

Intelligence or energy was declared by Joseph Smith in May, 1833, to be eternal: "Intelligence, or the light of truth, was not created or made, neither indeed can be."[A] In the sermon already referred to the Prophet said, "The intelligence of spirits had no beginning, neither will it have an end."

[Footnote A: Doctrine and Covenants, 93:29.]

These quotations, and many others to which attention might be called, show clearly that Joseph Smith taught the doctrine that the energy of the universe can in nowise be increased or diminished, though, it may manifest itself in various forms.

The great Latter-day prophet is thus shown to be in harmony with the second fundamental law of science. It is not a valid objection to this conclusion to say that Joseph Smith did not use the accepted terms of science. Words stand only for ideas; the ideas are essential. The nomenclature of a science is often different in different lands, and is often changed as knowledge grows.

It is hardly correct to say that he was in harmony with the law; the law as stated by the world of science was rather in harmony with him. Let it be observed that Joseph Smith enunciated the principle of the conservation of the energy, or intelligence as he called it, of the universe, in May, 1833, ten years before Dr. Joule published his famous papers on energy relations, and fifteen or twenty years before the doctrine was clearly understood and generally accepted by the learned of the world. Let it be also remembered that the unlearned boy from the backwoods of New York state, taught with the conviction of absolute certainty that the doctrine was true, for God had revealed it to him.

If God did not reveal it to him, where did he learn it, and whence came the courage to teach it as an eternal truth?

Chapter IV.

THE UNIVERSAL ETHER.

[Sidenote: The modern theory of light was established only about the year 1830.]

The nature of light has been in every age a fascinating subject for study and reflection. Descartes, the French mathematician and philosopher, advanced the hypothesis that light consists of small particles emitted by luminous bodies, and that the sensation of light is produced by the impact of these particles upon the retina of the eye. Soon after this emission or corpuscular theory had been proposed, Hooke, an English investigator of great note, stated publicly that the phenomena of light, as he had observed them, led him to the belief that the nature of light could best be explained on the assumption that light was a kind of undulation or wave in some unknown medium, and that the sensation of light was. produced when these waves struck upon the retina of the eye. This new hypothesis, known as the theory of undulations, after the great Isaac Newton had declared himself in favor of the corpuscular theory, was finally adjudged by the majority of students to be erroneous.

About the year 1800, more than a century after the days of Descartes, Hooke and Newton, an English physician, Dr. Thomas Young, who had long experimented on the nature of light, asserted that the emission theory could not explain many of the best known phenomena of light. Dr. Young further claimed that correct explanations could be made only by the theory of waves of undulation of an etherial medium diffused through space, and presented numerous experimental evidences in favor of this view. This revival of the old theory of undulation met at first with violent opposition from many of the greatest scientific minds of the day. Sometime after Dr. Young's publication, a French army officer, Augustine Fresnel, undertook the study of the nature of light, and arrived, almost independently, at the conclusion stated by Dr. Young. Later, other investigators discovered light phenomena which could be explained only on the undulatory hypothesis, and so, little by little, the new theory gained ground and adherents.

Still, even as late as 1827, the astronomer Herschel published a treatise on light, in which he appeared to hold the real merit of the theory of undulations in grave doubt.[A] Likewise, the Imperial Academy at St. Petersburg, in 1826, proposed a prize for the best attempt to relieve the undulatory theory of light of some of the main objections against it.[B] It was several years later before the great majority of the scientific world accepted the theory of undulations as the correct explanation of the phenomena of light.

[Footnote A: History of the Inductive Sciences, Whewell, 3rd edition,
Vol. II, p. 114.]

[Footnote B: Loc. cit., 117.]

[Sidenote: A subtle substance, the ether, fills all space.]

In brief, this theory assumes that a very attenuated, but very elastic, substance, called the ether, fills all space, and is found surrounding the ultimate particles of matter. Thus, the pores of wood, soil, lead, gold and the human body, are filled with the ether. It is quite impossible by any known process