And thus we come to the last question of all, What is it to live in Christ's name? For this does not mean simply to call one's self a disciple of Jesus and profess a faith in his religion. Such professions, when sincere, are good and ought to be made, but they do not begin to exhaust the meaning of these few words. You live in his name, just so far and only so far, as you live so that the name will fit you. When you stand where he would have stood were he now upon the earth; when you throw the whole weight of your influence into the scale which would have received his; when you approve what he would have approved, denounce what he would have denounced, and in all things speak as he would have spoken, and act as he would have done, — then you live in his name, because your life manifests the same spirit that was in him; and "if any man have not the spirit of Christ, he is none of his."

We have read of men and women, even if we have not known them, who, in spite of frailties and imperfections, bore nobly the Christian name, and never disgraced it. They are those who would not prostitute their heaven-born powers to any base purpose even to satisfy their craving for bread. They are those who would not renounce their allegiance to truth and righteousness even to gain the kingdom of the world and the glory thereof. They are those who kept steadily in the way of duty, and would not turn to the right hand or the left into any by-paths of sin and folly. And though in their humility they hardly dare assume the Christian title, much less assert their likeness to their leader, you are none the less sure that the same spirit which made Jesus the Christ has been born in them also, and that they are living, trusting, and working in his name.

RICHARD METCALF.

THE CALCULUS.

SPACE and time are so entirely diverse in their nature, that there is no connection or relation between them; except through the mind, as percipient of both; or through will, manifesting itself in motion. In contemplating space we see it as external to the mind; our consciousness does not sharply locate its own whereabouts; we fancy ourselves near the Eyegate or Eargate of the town of Mansoul; but cannot say precisely where our council chamber may be situated. Not so with time, our consciousness is sharply defined; we are neither in the past nor in the future; our conscious moment is the now, without duration. Hence we can more readily imagine ourselves freed from limitations of space than from those of time. We can imagine to ourselves time in the flow of our own thoughts; the thought of space necessarily takes us out of ourselves. But when we go out of ourselves and contemplate space, we carry time with us in the very action of our thought. In all closer contemplation of outlines, the attention is transferred successively to different points of the figure, and time is occupied by that transfer. Thus we come naturally, and almost inevitably, to regard the line as the path of a moving point, the surface as generated by a moving line.

Thus space and time, though heterogeneous, are united into one science of mathematics by human thought; and the laws of algebra, or time, are applied to geometry, or space. By this simple device, into which Descartes and Newton were led by nature's own guidance, the human mind has extended almost indefinitely its geometrical acquisitions; it was by carrying, as it were, its native element of time with it into the domain of space that it has conquered so vast a field.

When we remember how intense the delight which man feels in the discovery of mathematical truths; how many of the noblest thinkers of the race have owed their finest discipline to this pursuit; how rich the harvest of practical benefits which have flowed from the application of mathematics to the arts and sciences; how magical their effect has been in banishing superstition, and elevat

ing the general tone of human thought and human endeavor, we may surely own, with gratitude, the marks of divine wisdom and love, in this gift to man, of the power to penetrate space, and apply to it the laws of time. It is a peculiar gift, not a necessary accompaniment of intellect, for sometimes the brightest intellects possess it in only a very feeble degree. Thankfully, therefore, do we acknowledge the presence of an Infinite Spirit, giving good gifts to man in the inspiration of a Leibnitz and a Lagrange, as well as of a Handel and a Shakespeare.

The main source of this power given by algebra to the geometer, is the comprehensiveness of the language put into his hands. The introduction of general and abstract terms is always a means of enlarging the grasp of thought, and increasing the clearness of reasoning. Space has its three dimensions, its elements of magnitude and direction; and although, in one aspect, the simplest of all possible objects of thought, may yet, for purposes of reasoning concerning it, be advantageously reduced, by algebraical language, to the one term of quantity, capable only of flowing in one direction, and being considered as greater or less than a given magnitude. But the generality thus introduced is made vastly more general by using symbols which shall combine, in one letter, various forms and relations in space, defined according to judiciously selected and easily interpreted laws. Thus, for example, all possible triangles, plane and spherical, and all their properties are implied in the single equation, r = pq; and a similar condensation. of meaning is attained in mechanical science. Another source of the peculiar power of the calculus arises from the plasticity which it gives to infinitely rigid space. In experimenting upon a rectangular beam, cut from a round piece of timber, we can readily determine its strength when set edgewise; but cannot tell what the strength would have been had the sides been in different proportions. The rectangular parallelopiped inscribed in a cylinder is as absolutely fixed in its dimensions as the hewn timber, but by expressing those dimensions in language borrowed from the science of time, we can imagine them changing in their proportions, and the strength changing with them. Thus we can determine the precise proportion they must bear in order to give the strongest possible rectangular beam that could be cut from a round log.

This illustrates, by a simple example, the power given to geometry by Newton's conception of fluxions, his introduction of the idea of velocity into the consideration of form.

The appearance of the same algebraic law in the creation, under the two forms of time and space, has already been alluded to as proof of unity of design; the angles of leaves and the angular velocity of planets being expressed by the same series of fractions. Other examples confirm the sublime induction. The elasticities of gases, strings, and rods are so fundamentally different in kind that we see no connection between them. The elastic force of the stretched string we need not determine; that of the rod, and that of the gas, can be determined only by experiment, and when determined they have no very apparent connection or relation with each other. Nevertheless, each of the three has a peculiar relation to the force of gravity; of which it is, nevertheless, entirely independent. The velocity of a sound traveling in the air, near the earth, would be, were no heat developed in the action, equal to the velocity acquired by a body falling from a height equal to that which the atmosphere would have could it be all compressed to the density of that near the earth surface. The velocity of a wave traveling on a string is equal to that which would be acquired by a body falling from a height measured by the length of the same cord equal in weight to the tension of the string. And if we take a very fine glass thread by its two ends, the infinitely varied and beautiful forms which it can be made to assume, of waves and folds and kinks and loops, the figure eight and the circle, are all expressed in mathematical language by the same forms as those which express the motions of an ordinary pendulum, under the forces of gravity. The genetic connection, between these forms and these motions, we do not see, any more than that between the times of the planets and the angles of the leaves, but the intellectual connection we detect, and it leads us to recognize with reverential awe the presence of Intellect in the disposition of the particles of both gaseous and solid bodies.

THOMAS HILL.

LITERATURE FOR THE YOUNG.

[We desire to call especial attention to this article as an official communication prepared, at our request, by the Ladies' Commission on Sunday-school Books. Only those among our readers who are unfamiliar with the activities of the Unitarian denomination will need to be informed that this Ladies' Commission was organized nine years ago in order to select, for recommendation to Sunday schools and to families, suitable books for the young. It was made up of ladies of the highest literary and religious culture. During all these years they have devoted themselves, with the most painstaking assiduity, to the work, of which they have realized more and more the importance as they have learned to know more completely with what a mass of unprofitable or pernicious reading our generation is being flooded. By their wise judgment and taste and fairness they have won the confidence of other denominations as well as of our own; and we anticipate as the result of their labors, when these shall have become more generally known, not only a service to those who may avail themselves of their catalogues in the purchase of books, but an influence on publishers and authors in the production of this class of literature. If once public sentiment shall fairly be roused to the importance of the right sort of reading for the young, - and to the poisoning nature of much that is now most widely circulated, — the makers of books will be compelled to conform to a higher moral and religious and literary standard. ED.]

THE Ladies' Commission on Sunday-school Books examined, from October, 1873, to May, 1874, three hundred and fortythree books, and approved eighty-two. The Supplement to the Catalogue of 1871, which has just been issued, contains the titles of all books recommended during the past three years. Italics are used to indicate those approved since October, and they are mostly publications of the past year.

Perhaps the question most frequently asked in regard to our work is why we reject annually so large a proportion of the books that we read. Therefore, as we have now for several years based our decisions upon some general principles of criticism, we venture to give certain classes of objections to books for the young, which are clear in our minds. And without involving ourselves as a body in the invidious and dangerous work of publishing our reasons for rejecting special books, we are willing, in answer to