IPSWICH:

COWELL, BUTTER MARKET.

PREFACE TO THE FIFTH EDITION.

I AM informed by the Publishers that this Fifth Edition is required to meet the demand of a somewhat wider class of students than those for whom the Lectures were originally intended.

This circumstance, as well as the advances made in Astronomical science during the period which has elapsed since the Lectures were delivered, have rendered it desirable that some very slight modifications should be made in the text, and that some additions should be made in the form of Appendix.

I am happy to state that Mr. Stirling has been at liberty to prepare the modifications and additions

to which I allude, and to undertake the general editing of the book. And I now issue the work to the public, with the increased confidence derived from the assistance of a friend on whose ability I place complete reliance.

ROYAL OBSERVATORY,

GREENWICH, 1866, June 9th.

G. B. AIRY.