Page:Littell's Living Age - Volume 130.djvu/706

698 of his "Philosophy of the Inductive Sciences," Dr. Whewell conceived that he had proved, à priori, that all matter must be heavy. He was well acquainted with the history of the establishment of the law of gravitation, and knew that it was only by careful experiments and observations that Newton ascertained that the effect of gravitation on two equal masses is the same whatever be the chemical nature of the bodies, but in spite of this he maintained that it is contrary not only to observation but to reason, that any body should be repelled instead of attracted by another, whereas it is a matter of daily experience, that any two bodies when they are brought near enough, repel each other.

The fact seems to be that, finding the word weight employed in ordinary language to denote the quantity of matter in a body, though in scientific language it denotes the tendency of that body to move downwards, and at the same time supposing that the word mass in its scientific sense was not yet sufficiently established to be used without danger in ordinary language, Dr. Whewell endeavored to make the word weight carry the meaning of the word mass. Thus he tells us that "the weight of the whole compound must be equal to the weights of the separate elements."

On this Mr. Todhunter very properly observes: —


 * Of course there is no practical uncertainty as to this principle; but Dr. Whewell seems to allow his readers to imagine that it is of the same nature as the axiom that "two straight lines cannot inclose a space." There is, however, a wide difference between them, depending on a fact which Dr. Whewell has himself recognized in another place (see vol. i., p. 224). The truth is, that strictly speaking the weight of the whole compound is not equal to the weight of the separate elements; for the weight depends upon the position of the compound particles, and in general by altering the position of the particles, the resultant effect which we call weight is altered, though it may be to an inappreciable extent.

It is evident that what Dr. Whewell should have said was: "The mass of the whole compound must be equal to the sum of the masses of the separate elements." This statement all would admit to be strictly true, and yet not a single experiment has ever been made in order to verify it. All chemical measurements are made by comparing the weights of bodies, and not by comparing the forces required to produce given changes of motion in the bodies; and as we have just been reminded by Mr. Todhunter, the method of comparing quantities of matter by weighing them is not strictly correct.

Thus, then, we are led by experiments which are not only liable to error, but which are to a certain extent erroneous in principle, to a statement which is universally acknowledged to be strictly true. Our conviction of its truth must therefore rest on some deeper foundation than the experiments which suggested it to our minds. The belief in and the search for such foundations is, I think, the most characteristic feature of all Dr. Whewell's work. Author:James Clerk Maxwell.

 

 From The Economist.

policy does not easily seize hold of the imaginations of Englishmen, and it is with great difficulty that either the intellectual interests or the moral sympathies are fixed upon the confused and complicated incidents of a warfare, such as is now being waged upon the borders of Servia. But when a view of any such controversy does get hold of the popular mind, it is apt to be fierce and persistent, for it is not modified by any direct weighing of evidence. It is most frequently through the emotions that such a view of distant events acquires power, and being almost beyond the pale of reasoning, it is likely to become a dangerous force in politics. Thus, we believe, the Crimean War was the direct consequence of a popular impulse, which had its root in the inaccurate judgment of the English people upon some ambiguous acts and expressions of the emperor Nicholas, for the explanations and modifications of which no hearing could be obtained. We are not without apprehension that the present temper of the public mind is now as dangerously bent upon the opposite course. The moral effect produced by the history of the Turkish atrocities in Bulgaria has been rarely paralleled in this country. While foreign critics, who generally miss the point of popular movements in England, are declaiming against the English government as the protector and patron of the Turk, the real danger is not that England may plunge into war or involve herself in diplomatic meshes in defence of the Ottoman government, but that she may be forced into a military or political 