PREFACE. THE elementary treatises on Astronomy already extant, are numerous; and the authors of some of them have evinced great knowledge and ability. It may therefore be expected, that he who ventures to add to their number, should at least produce a substantial plea for such an obtrusion on the public notice. It may be expected that he should be either an accurate observer of the celestial bodies, or a profound mathematician. I have no claim to either the one or the other of these distinctions; and must therefore plead another apology. In the early part of last winter, a Letter was addressed to me, signed by thirty persons, inhabitants of Tottenham, requesting me to deliver a Course of Lectures on Astronomy. The invitation was not to be resisted; and I undertook the pleasing task without any other expectation of reward, than such as might arise. from the hope of being useful, and without any intention of offering the Lectures to the notice of the public. Solicitations to publish them on the part of several in 6 dividuals of the audience, were resisted on the ground of my not possessing in a sufficient degree, either of the qualifications before mentioned. The desire for their publication, however, seems to have been more general than I was then aware of; for soon after their conclusion, I received a Letter signed by upwards of sixty of the audience, requesting me to publish them from a desire that they may become more extensively and permanently useful;' as being peculiarly adapted, from their simplicity, to the use of young persons, and those not conversant with the science.' This testimonial, far exceeding my most sanguine wish, was accompanied by another and more substantial, though not more flattering expression of satisfaction on the part of some of the audience; for the testimonial itself was rendered doubly gratifying, from the consciousness that it was signed by several, whose knowledge of the science is far superior to my own. I repeat that, in undertaking these Lectures, the hope of being useful was my only object. And, being aware from past experience, that a large proportion of those who might be expected to attend them, would consist of young persons, many of whom were altogether unacquainted with the science; it became my anxious determination to render them as simple as possible, as the only means of their being advantageous to that class of my hearers. Having this object chiefly in view, it is scarcely needful to say, that, taking for granted the truth of the sublime results afforded by the joint labours of the observer and *I allude to my Lectures on Mineralogy and Geology, for merly given at the same place, and which are before the public. the mathematician, these were illustrated by the most simple means that I could find or could devise, or were substantiated by such proofs as were most intelligible; leaving unattempted the more abstruse and satisfactory illustrations afforded by the mathematics. The reader is now in full possession of my motive for undertaking these Lectures, and of my plea for publishing them; and he will be convinced from what has been said, that if he has already given attention to the science of Astronomy, he must not expect to gain any thing by the perusal of them. It has been well observed that, 'The chief difficulty in any elementary work of science is, to catch the ideas which lead from ignorance to knowledge; but in most works of this nature, the author seems to infer that the reader is in a considerable degree acquainted with the subject; and, while he is in the ship of science, expects that the disciple can arrive without a boat.'* This observation is forcible; and, as it appears to me, may, without attempting in any degree to undervalue the many excellent elementary treatises on this science now existing, be applied without injustice to too many of their authors. The numerous and difficult, yet expressive terms of this science are generally used (it will be owned by the pupil at least) without sufficient forbearance; and due regard is not always apparent to that gradual developement, which, involving no point that has not been adequately explained, forms one of the chief excellencies of an elementary treatise. These, together with the absence of some explanations which, by * Pinkerton's Geography, vol. 1. Introductory Observations to Extracts from Bailly's Origin of Astronomy and Geography. comparison with others, may be esteemed little or insignificant, or sufficiently obvious of themselves, commonly form the chief obstacles to the progress of the learner, and the principal causes of confining to a few, even such a knowledge of this interesting science, as may be gained without recourse to the mathematics. The terms, I endeavoured to avoid, or to explain fully such as were used; but, being persuaded that due attention on the part of the learner to the minor and more obvious points connected with the science, is materially advantageous to him, inasmuch as they frequently furnish 'the ideas which lead from ignorance to knowledge,' I studiously endeavoured to bring them under view. The motives which led to the choice of the arrangement that was adopted, are detailed in the Lectures. It may not however be amiss here to say, that it seemed to be the most simple, as admitting of the most gradual developement; and therefore as being calculated to lead on most invitingly to the more intricate parts of the science. In the unfolding of such as I attempted to explain, a regard was had to plainness of language, which would necessarily have been tedious to the scientific; but which is, as I conceive, highly advantageous to the learner who also will more readily excuse the occasional or even frequent repetition that will be found in the following pages. Its utility in public lectures cannot be disputed, as being the most satisfactory mode of connecting fact with deduction; and as serving, at the same time, to impress on the mind of the pupil, the more prominent and interesting points of the science and although it is frequently destructive of elegance, and of that easy flow of language which is inviting to the stu |