Page:Popular Astronomy - Airy - 1881.djvu/11

 Rh merely subsidiary,) and the principles on which the observations made with these instruments are treated for deduction of the distances and weights of the bodies of the Solar System, and of a few stars, (omitting all minutiæ of formulæ and all troublesome details of calculation). To attempt to go further than this would, in fact, amount to undertaking a complete work on Astronomy, which was far beyond my intentions. Such an opportunity appeared to present itself in the course of Lectures which I engaged to give to the Members of the Ipswich Museum and their friends. And the ideas which I have enounced above have been carefully kept in view, in the object and in the details of every Lecture.

I have endeavoured in the first place, to point out how much of the fundamentals of Astronomy may be obtained with the coarsest observation with the unaided eye. And here I should remark, that the science which is thus obtained by personal observations is vastly superior (as far as it goes) to that which is obtained by any other method. The knowledge derived from Lectures is exceedingly imperfect: that derived from careful reading is admirable for its accuracy and fulness, but occupies the mind rather as a train of internal ideas than as a series of consequences deduced from the observations of nature: but that inferred from actual personal observation carries with it a degree of reality and certainty, as the veritable science of external objects, which nothing else can give.

I have endeavoured, in the next place, to show