LECTURES ON PRACTICAL ASTRONOMY AND ASTRONOMICAL INSTRUMENTS - 1879 - PREFACE. - 1 BEGAN in the year 1843 a Course of Lectures on , Practical Astrofiomy and Astronomical Instruments, having been at that time seven years irectorof the Cambridge Observatory. Lectures on these subjects had already been given by Dr Peacock as Lowndean Professor, which he discontinued on the understanding that I would undertake to C - c arry them on. The circumstances that an Astronon ical Observatory so well appointed as that of Cambridge was near at hand, and was e provided with various instruments of first-rate quality, appeared to me to2 give facilities for lecturing on Practical Astronomy which ought to be taken advantage of and accordingly I commenced lecturing in the abovenamed year, having previously produced a jllabuso f the subjects of the lectures, and procured a considerable number of wooden models, which, together with some apparatus that had been collected by Professor Peacock, I made use of in conducting and illustrating the Lectures.-I had also the advantage of having at corninand several portable instruments pertaining to the Observatory,. At the end of the Syllabus a list of formulae applicable to the reduction of astronomical observations was introduced, accompanied by brief demonstrations. Also in giving the lectures orally, I adopted the plan of exhibiting in ink-writing on large sheets of white paper descriptions of the instruments, and investigations of formulae, with the requisite illustrations by Figures, all being of such size as to be readily seen by the students from their seats. I had recourse to this method of lecturing partly because I thought it would serve to convey adequate information with little expenditure of the students time, and partly because I was unable to meet with a text-book on this department of Astronomy which I could regard as sufficiently accurate and complete. The contents of the Syllabus, together with the explanations inscribed on the above mentioned papers, have formed the ground-work of he present publication. In fact, as far as regards the divisions of the subjects treated of under the head of each instrument, and the order of their treatment, the Syllabus has been closely fonowed but in the course of writing the Treatise, the composition of the Lectures, as originally conceived, has been in various respects modified and added to. The subjects which make up the additional matter are the following-A method of correcting the errors of a transit-instrument for deviation of the pivots from the cylindrical form a detailed description of the construction and applications of the collimating eye-piece the chronographical method of registering transit-observations a discussion respecting personal equation in taking eye-and-ear transits an experimental investigation of the effect of. the flexure of a Mural Circle on the mean of its Microscope-readings a depcription of the construction of the new Transit-Circle ok the Cambridge Observatory and... --This text refers to an alternate Paperback edition.