William Tyler Olcott

“ The book will be distinguished from other volumes on popular astronomy by a somewhat novel system of mapping, and by an unusually full discussion of the uses of the simpler astronomical instruments. Here too, however, the treatment is definite and practical. Questions of optical theory and construction are subordinated to the pointing out, by the author, of the objects that can be seen, and of the satisfactions that may be obtained, first with the unaided eye (the fundamental optical instrument) , and then with the opera-glass, field-glass, and telescope. ”

“ The author has found by experience that what the student most needs when he is observing with a telescope, is a page to glance at that will serve as a guide to the object he desires to view, and which affords concise data relative to that object. The diagrams therefore direct the student's vision and the subject-matter affords the necessary information in each case. ”

“ It has been necessary to curtail many parts of the history, to lay before the reader in unlimited space enough about each age to illustrate its tone and spirit, the ideals of the workers, the gradual addition of new points of view and of new means of investigation. ”