compass. For these three things have changed the aspect and condition of the affairs of the world; the first, in literature; the second, in war; and the third, in navigation." And what might be expected when the minds of men were mainly bent upon such inventions his far-seeing eye discerned with almost a prophetic spirit. "Looking back," he says, "into that I have passed through, this writing seemeth to me, si nunquam fallit imago, as far as a man can judge of his own work, not much better than the noise or sound which musicians make while they are tuning their instruments, which is nothing pleasant to hear, and yet is the cause why the music is sweeter afterwards. So have I been content to tune the instruments of the Muses, that they may play that have better hands. And surely when I set before me the condition of these times, in which learning hath made her third visitation or circuit in all the qualities thereof; as the excellency and vivacity of the wits of this age, the noble helps and lights which we have by the travails of ancient writers, the art of printing which communicateth books to men of all fortunes, the openness of the world by navigation, which hath disclosed multitudes of experiments and a map of natural history; the leisure wherewith these times abound, not employing men so generally in civil business, as the states of Græcia did in respect of their popularity, and the state of Rome in respect of the greatness of their monarchy; the consumption of all that ever can be said in controversies of religion, which have so much diverted men from other sciences; and the inseparable propriety of time which is ever more and more to disclose truth, I cannot but be raised to this persuasion that this third period of time will far surpass that of the Grecian and Roman learning: only if men will know their own strength and their own weakness both, and take one from the other, light of invention, not fire of contradiction; and esteem of the inquisition of truth as an enterprise, and not as a quality or ornament;

and employ wit and magnificence to things of worth and excellency, and not to things vulgar and of popular estimation." In the full faith that the path of science, into which he would lead men, would do honour to God as well as confer the highest benefits upon his fellow-creatures, he presents his work in humble confidence as no unworthy offering to the Divine Being. "He will regard with His benign favour this my attempt to write the apocalypse, and true vision of the footsteps and seals of the Creator upon His creatures. Wherefore, do thou, O Father, who gavest the visible light as the first-fruits to thy creature, and as the crowning-piece of thy works did'st breathe intellectual light into the face of man, defend and guide this work; which, proceeding from thy goodness, aims to reflect thy glory. Thou, when thou turnedst to behold the works which thine hands had made, sawest that they all were very good and restedst. But man, turning to the works which his hands have made, sees that they are all vanity and vexation of spirit; and he can find no rest. Wherefore, if we will labour in thy works, thou will make us partakers of thy vision and of thy sabbath. We come as supplicants to beg of thee that this may be our mind; and that by our hands, and by those of others to whom thou shalt grant the same mind thou wilt bestow new alms upon the human family."

Already was this noble prayer in the course of fulfilment when it was uttered. Men arose rapidly to be the ministers and interpreters of nature. Bacon died in 1626, and in 1642 Newton was born, that great interpreter of God's physical laws. Science after science came to be established upon its true principles which men had before been working at for ages almost without obtaining a glimmer of light. All that could heretofore be predicted in astronomy was derived merely from observation and experience; there was no fundamental principle by means of which results could be calculated; but when Newton detected the simple law,

that bodies attracted each other by a force which diminished exactly in proportion to the space over which it was dispersed, or, in mathematical language, varied inversely as the square of the distance then the means were given for calculating exactly the future position of the heavenly bodies at any required time. Tables could now be formed of the greatest use to astronomers and travellers, whether by land or by sea. So exact is the operation of this law, that when a prediction has been founded upon proper dates, we may be assured that its fulfilment in point of time will take place with absolute exactness. Every apparent deviation has only served to lead astronomers to some phenomenon, which had before been overlooked or undiscovered. Thus, exact calculations and observations of the moon's motions and librations showed the necessity of taking into account, not only the whole mass of the earth, but its trifling deviation in shape from exact roundness, because the protuberant parts must, in the fulfilment of the law, produce a certain small effect on the moon's motion. In like manner the singular discovery of the existence of a planet which had never been seen, simply by its effect upon another planet when in its vicinity, an effect so trifling that it could only be determined by long and careful observations, shows how absolutely we may now depend upon the principles by which the phenomena of the heavens are predicted.

Another science has made still more gigantic strides since Bacon, and promises to produce (may I not say is already producing) unparalleled effects upon human society. When a boy, I remember amusing myself, with others, in rubbing bits of sealing-wax on our coat sleeves, and watching the motion up and down of little bits of paper, when the wax was held over them. The substance in which this property of attracting light bodies was first observed was amber (called, in Greek, electron). All that was known about it for ages was the simple effect which I have just described, ap

parently more suited to amuse a child than to engage the thoughts of a philosopher. But who can tell what secrets may be under the slightest hints which nature gives? Little did the ancient sage who first noticed this property imagine what would one day result from it. The new school of the interpreters of nature must pry into this also. How did the force act? How could it be increased? These questions led to the invention of the electrical machine and the Leyden jar; and then came Franklin's brilliant discovery, that this subtle agent was no other than the very lightning of heaven, and thence we learnt how to protect ourselves from the thunderbolt. Nor did the course of discovery stop here. A kindred agency had been discovered by means of the galvanic pile, and Galvani and Volta showed that this had a close relation with the power upon which depend the various motions of animal life. Then the attractive power of the magnetic needle was examined, and turned out to be apparently only another manifestation of the same subtle agent; and it was found that similar effects could be produced either by the electrical machine, the valvanic or voltaic pile, or a combination of magnets. The effects of these discoveries upon the arts of life have been as wonderful as the discoveries themselves. In chemistry, substances, which were proof against the most powerful agents previously known, have yielded to the analysing power of the galvanic current. By a process which appears little less than miraculous, the same current can not only resolve a metal into its most subtle elements, but re-form them again into any shape we please, serving to the ends of economy as well as to the multiplication of objects of beauty and art. I need not remind you what the same agent does in its application to the telegraph, of which future history will have to tell the triumphs over the casualties to which man is subject. But, beyond all this, it has been discovered that not only individual organisms, but the whole earth itself is vivified, if I may so speak, by this subtle principle;

and, as in the animal frame it generates the pulsations which send the vital fluid thrilling through every limb, so its throbbings can be detected in every part of the earth's surface, and the investigations are in progress for determining the laws by which it is governed. One remarkable observation bringing us to the utmost verge of our discoveries in this subject I cannot give you better than in the words of Professor Owen. "It has been determined that there are periodical changes of the magnetic elements, depending on the hour of the day, the season of the year, and on, what seemed strange, intervals of about eleven years. Also that, besides these regular changes, there were others of a more abrupt and seemingly irregular character-Humboldt's magnetic storms-which occur simultaneously at distant parts of the earth's surface. Major-General Sabine, than whom no individual has done more in this field of research since Halley first attempted to explain the change in the variation of the magnetic needle, has proved that the magnetic storms observe diurnal, annual, and undecennial periods. But with what phase or phenomenon of earthly or heavenly bodies, it may be asked, has the magnetic period of eleven years to do? The coincidence which points to, if it does not give the answer, is one of the most remarkable, unexpected, and encouraging to patient observers. For thirty years a German astronomer, Schwabe, had set himself the task of daily observing and recording the appearance of the sun's disc, in which time he found that the spots passed through periodic phases of increase and decrease, the length of the period being about eleven years. A comparison of the independent evidence of the astronomer and magnetic observer has shewn that the undecennial magnetic period coincides both in duration, and in its epochs of maximum and minimum with the same period observed in the solar spots."

Photography is now employed to record the exact condition of the sun's spots, and to ascertain the