The nomical Society's Notices,' and Plate VIII., that they are far the most accurate graphic representations that have yet been made of this or any other transit. views on pp. 446, 447, though small, illustrate the transit of 1882 more accurately than any views yet made, so far as I know. The note on pp. 443-445 serves to indicate the circumstances under which my investigation of the transits of 1874 and 1882 led me to indicate my dissent from the views which the Astronomer Royal had propounded on the same subject. It was not easy-or rather it was not possible-for me to exhibit my results without pointing out how and why they differed from Professor Airy's, which had been for so many years before the public. The accuracy of my results has now been established, and has indeed never been doubted. The only question which remains at issue is whether I was right or wrong in regarding the corrections as important. While expressing my own unchanged conviction that the corrections are of vital importance, I am quite content to let others decide whether this conviction is well or ill-founded. In Chapter II. a detailed account is given of the Sun's influence as ruler over the system of planets. Many of the relations here dealt with are novel and I think interesting. In the last three chapters I deal with the Sun's physical condition, his position as fire, life, and light of the solar system, and his place and motions among his fellow-suns. It will be seen that in Chapter VIII. I have presented reasons for considering that the most important work science has to accomplish is to show how the Sun's action can be more fully utilized than it is at present, so that before the Earth's stores of force are exhausted (as they must some day be), resources which can never be exhausted --because unceasingly restored-may be rendered available. The treatment of the subject of eclipses in Appendix B is novel. It seemed to me that there was room for a more thorough explanation of the general laws on which the recurrence of eclipses depends, than finds place in our text-books of astronomy*—the authors of * In this connection, it is necessary for me to note that I have had occasion to claim in fig. 8, p. 21, and foot-note, pp. 25, 26, a drawing which appears at p. 185 of Mr. Lockyer's Elementary Lessons in Astronomy. This drawing, and other matter which he has paid me the compliment of employing in his useful little book, may be of small importance, and it would be absurd to suppose that in a text-book no materials should thus be borrowed. But it has been convenient to me here—and may be convenient again—to make use of my own work; and I would rather not appear to borrow (at least without proper acknowledgment) from Mr. Lockyer. This feeling seems so natural, that it has been with surprise I have found Mr. Lockyer objects to it. In a letter to Messrs. Macmillan, for me, he has expressed a somewhat angry satisfaction that though he has borrowed in the same work and way from many others, no one has remarked upon it but myself. (A mistake, however.) My remarks were sufficiently gentle, and all I asked was that by associating my name with my own results (some of which had only been obtained after much labour) he would place it in my power to employ those results.' For, else, I should seem to be acting unfairly towards him, by using his work without that acknowledgment which justice and courtesy alike require in such cases. I certainly had no thought of angering him, and it has been with sincere regret that, since then, I have seen his anger leading him to say and do many things which I am sure he will regret in the cooler after-years. which have been content for many years to follow each other, as respects this matter, along a somewhat unsatisfactory track. It only remains for me to point out that in some of the notes I deal with matters and employ methods of treatment which would not be suitable for the main text. The general reader can omit these notes altogether, as they are not necessary for the elucidation of the subject and have only been introduced for the benefit of those more advanced students of astronomy who might desire to see certain points more thoroughly dealt with than they could be in the body of a popular treatise like the present. LONDON: December 1870. RICHARD A. PROCTOR. Mode of measuring distance of inaccessible object Applicable to the Moon but not to the Sun 7 Encke's analysis of the observations of 1761 and 1769. Other modes of estimating the Sun's distance :- Moon's parallactic inequality Earth's motion round centre of gravity of Earth and Moon 60 |