If the Solar System had comprised in itself the whole material creation, it would alone have abundantly sufficed to declare the glory of God, and in our brief review of its greatness and its wonder we have seen enough to awaken the most impressive thoughts of His power and wisdom. But that system is but as a single drop in the ocean. What boundary may be set to creation we know not, but we can trace it far enough to perceive that, as far as our senses are concerned, it cannot be distinguished from absolute infinity: and in leaving our Sun and his attendants in the background, we are only approaching more amazing regions, and fresh scenes will open upon us of inexpressible and awful grandeur. We are now to contemplate not one Sun, but thousands and myriads: — not a planetary system of subordinate globes, but aggregations of Suns; — pairs, groups, galaxies of Suns — “the host of heaven,” — all independent in unborrowed splendour, yet many evidently, and all by clear implication, bound together by the same universal law which keeps the pebble in its place upon the surface of the earth, and guides the falling drop of the shower, or the mist of the cataract.

Congratulate us, Gassendi, on clearing from suspicion your observation of Mercury, and let astronomers cease to wonder at the surprising smallness of the least of the planets, now they find that the one which seemed the largest and brightest scarcely exceeds it. Mercury may well bear his loss since Venus sustains a greater.

I observed the diameter of Venus (Chap. I.) to be 1′ 12″, the Sun being 30′; therefore the latter being 31′ 30″, the true diameter of the former is 1′ 16″. My friend Mr. Crabtree's observation agrees with this calculation: I am sure she did not appear greater; if there is any error, it is in an excess. There is no reason why any one should doubt the truth of the observation; unless indeed he is unacquainted with the telescope, or influenced by the knavery of the Peripatetics, or suspects our honesty; and I all not stay to argue either with those who have not seen this instrument or who mistrust its fidelity, for it is vain to contend with ignorance and self-will. Permit me to remind any who may suspect our good faith, how easy it would be to investigate the subject for themselves, and how little it would serve our purpose to distort truth by falsehood.

Let us then examine the opinions of others, in order that it may appear with what degree of accuracy astronomers have hitherto estimated the magnitudes of the stars.

I shall here say something which may tend to throw light upon the dimensions of the stars, and upon the horizontal parallax of the Sun, a matter of the greatest importance, and one which has been the subject of much fruitless speculation; but I will not speak dogmatically, nor, as I may say, “ex cathedrâ,” but rather for the sake of promoting discussion, and with the view of examining other men's opinions.

John Kepler, the prince of astronomers, speaking of the relative proportion of the planets (Astr. Cop. page 484), thinks it “quite agreeable to nature that the order of their magnitudes and of their spheres should be the same; that is to say, that of the six primary planets, Mercury should be the least, and Saturn the largest, inasmuch as the former moves in the smallest, and the latter in the largest orbit.”

“But as the dimensions of their bodies may be regarded as threefold, either according to their diameters, their superficies, or their bulk,” he is doubtful which should be preferred. He thinks the first proportion “to be beyond question contrary to original reasons, as well as to the observations made on the diameters by means of the Belgian telescope.” He advocates the second, because the original reasons are preferable; whilst Remus Quietanus, a man well versed in practical observations, defends the third; and with him Kepler at length agrees, retaining this proportion in the Rudolphian tables.

We have already spoken of the hour of the true conjunction in respect of the ecliptic, but as that was not the middle of the transit, nor was there shewn in it the nearest distance of the centres, it may perhaps be agreeable to some, though it is not otherwise of much use, to assign the true middle, together with the beginning and end, of so unusual and wonderful a conjunction. For this purpose, let a figure be drawn, such as No. 3 in the preceding plate, and let C be the Sun's centre; N the Northern node; E C N the ecliptic; I N the orbit of Venus; I the beginning of the transit; M the middle; F the end; V the true conjunction in respect to the ecliptic; C V the latitude of Venus at its true conjunction; C M the least distance of the centres in the middle of the transit; C N the distance of the node from the place of the true conjunction; E N I the visible inclination of the orbit of Venus to the ecliptic.

The value of this observation, in correcting the motion of Venus, has already been explained. We must next ascertain how the facts which are deduced from it agree with the calculations of astronomers. This inquiry will doubtless shew the usefulness of the observation to the practical student; especially as it will appear that even the best astronomers have not only disagreed among themselves, but have considerably deviated from the truth.

There are four astronomers from whose tables Ephemerides are at this time chiefly computed, into whose respective merits, as there is some difference of opinion, it may be well carefully to inquire.

1st. Copernicus who compiled the new, or rather the renewed, hypotheses, and the laws of the sidereal motions, in six books of Revolutions, from which Erasmus Reinhold afterwards constructed the Prutenic tables; and from these, Origanus, Maginus, and others derived their Ephemerides which are still extant, and are chiefly used in our prognostics, though now the Prutenic calculation is held in less esteem.

2nd. Longomontanus, the disciple of Tycho Brahé, and as it were the heir of his discoveries, who, in his Danish astronomy, treading faithfully in the footsteps of his master, brought to a conclusion those things which Tycho was by death prevented from finishing.

3rd. The sagacious Kepler, who formerly assisted Tycho in his calculations, was afterwards astronomer to three Emperors, and happily effected the renovation of the science by the publication of the Rudolphian tables, to which his other writings may be considered a prelude.

When my father was engaged in writing the Biographical department of the history of Lancashire, he was naturally led to consider the merits of Jeremiah Horrox, the youthful astronomer of that county; and he was so much impressed with his distinguished scientific attainments that, finding it impossible from want of space to do him justice in those pages, he proposed on some future occasion to publish his life in a separate form. Accordingly, he ascertained the precise value of his discoveries, and gathered together much interesting detail connected with his personal history; and he also set about preparing a translation of his celebrated Treatise upon the transit of Venus over the Sun. But he did not live to complete this work. It would appear that much material had been accumulated, but that the arrangement of it had not even been commenced. To him however belongs the credit of being the first and only person who has undertaken to supply what is acknowledged to be a deficiency in the literature of our country; and there can be no doubt that, if his life had been spared a little longer, he would have produced a most interesting and instructive volume. Professor Rigaud, of Oxford, who was his friend and associate in these pursuits, says in his “Correspondence of Scientific Men of the 17th century,” that “the late W. R. Whatton, Esquire, had made considerable collections for a life of Horrox, which he intended to have prefixed to a new edition of the Venus in sole visa, when death in 1835 deprived the world of the fruit of his inquiries.”

I shall commence with the incomparable Copernicus, the successful reviver of what Gellibrand calls the “noble hypothesis of the motion of the Earth,” whom all the lovers of astronomy have hitherto followed, and will doubtless continue to do. Having long contemplated and admired a philosophy so sublime and so worthy of a Christian, I thus expressed my aversion to the puerile fictions of the pagan Ptolemy:—

The most skilful astronomers in their observation of Mercury have been frequently deceived; firstly, those, who in the time of Charlemagne, on the 16th of April in the year 807, believed that the transit of Mercury over the Sun continued eight days: secondly, Averrhoes, who says in the Ptolemaic Paraphrase, that he recollected to have seen something of a darkish appearance, and subsequently found by the numbers that the conjunction of Mercury and the Sun had been predicted; he flourished about the year 1160 of the christian era: thirdly, Kepler himself, the most learned astronomer that ever lived, was greatly deceived on the 18th of May 1607. All these having seen spots on the Sun's disc, an appearance not understood in those days, rashly concluded them to be the planet Mercury; but they were evidently misled, as circumstances afterwards proved.

Are we then similarly deceived, and do we mistake an ordinary spot for Venus?

Verily since this may be doubted, as well by some who are unacquainted with the heavens except from books, as by others who are learned and practical astronomers; and lest our labor should be in vain, it may be worth while, before further prosecuting the enquiry, to prove in a satisfactory manner that the planet Venus was the actual cause of this appearance.

Soon after the commencement of my astronomical studies, and whilst preparing for practical observation, I computed the Ephemerides of several years, from the continuous tables of Lansberg. Having followed up the task with unceasing perseverance, and having arrived at the point of its completion, the very erroneous calculation of these tables, then detected, convinced me that an astronomer might be engaged upon a better work. Accordingly I broke off the useless computation, and resolved for the future with my own eyes to observe the positions of the stars in the heavens; but lest so many hours spent on Lansberg should be entirely thrown away, I made use of my Ephemerides in ascertaining the positions of the distant planets, so that I was enabled to predict their conjunctions, their appulses to the fixed stars, and many other extraordinary phenomena. Delighted for the time with such a foretaste of the science, I took great pains carefully to prepare myself for further observation.

Whilst thus engaged, I received my first intimation of this remarkable conjunction of Venus with the Sun; and I regard it as a very fortunate occurrence, inasmuch as about the beginning of October, 1639, it induced me, in expectation of so grand a spectacle, to observe with increasd attention. I pardon, in the meantime, the miserable arrogance of the Belgian astronomer, who has overloaded his useless tables with such unmerited praise, and cease to lament the misapplication of my own time, deeming it a sufficient reward that I was thereby led to consider and to foresee the appearance of Venus in the Sun.

When first I began to attend to this Conjunction, I not only determined myself to watch diligently an appearance so important, but invited others also whom I knew to be interested in astronomy to do the same, in order that the testimony of many observers, should it so happen, might more firmly establish the truth; and especially because, if observations were made in different places, our expectations would be less likely to be frustrated by a cloudy sky or any other obstacle. I wrote therefore immediately to my most esteemed friend William Crabtree, a person who has few superiors in mathematical learning, inviting him to be present at this Uranian banquet, if the weather permitted; and my letter, which arrived in good time, found him ready to oblige me; he therefore carefully prepared for the observation, in a manner similar to that which has been mentioned. But the sky was very unfavorable, being obscured during the greater part of the day with thick clouds; and as he was unable to obtain a view of the Sun, he despaired of making an observation, and resolved to take no further trouble in the matter. But a little before sunset, namely about thirty five minutes past three, certainly between thirty and forty miuntes after three, the Sun bursting forth from behind the clouds, he at once began to observe, and was gratified by beholding the pleasing spectacle of Venus upon the Sun's disc.