Page:Popular Astronomy - Airy - 1881.djvu/18

4 concerned in the various branches of science, has been enabled to learn that, whereas on the one hand those who are commonly called philosophers may be as narrow-minded as any other class, and as little informed; so on the other hand, those who have to gain their daily livelihood by handicraft, may associate their trades or businesses, whatever they may be, with accomplishments of the most perfect and the most elevated kind. I think, then, it is right I should repeat, that these Lectures will be directed in some measure with the object of being perfectly comprehended, by that class of people. It is not my object, however, to deal with what may be called the picturesque in Astronomy. I have proposed it to myself as a special object, to show what may be comprehended, by persons possessing common understandings and ordinary education, in the more elevated operations of astronomical science. The Lectures will be, therefore, of what I may call a mathematical kind. But in speaking of this, I beg that the ladies present will not be startled. I do not mean to use algebra or any other science, such as must be commonly of an unintelligible character to a mixed meeting. When I used the word mathematical, I mean that it will be my object, to show how the measure of great things may be referred to the measure of smaller things; or to sum up in few words, it will be my object in an intelligible way, to show the great leading steps of the process by which the distance of the sun and the stars is ascertained by a yard measure—the process by which the weight of the sun and the planets is measured by the pound weight avoirdupois. Occasionally I shall be prepared to go into details; but my principal business will be to show the great steps upon which those who wish to