The opening of Preface
The object of the present work is not so much to instruct as to suggest. It represents a sort of reconnaissance, and embodies the information collected by scouts and skirmishers regarding practicable lines of advance and accessible points of attack, with a view to annexing for the realm of knowledge some further strips and corners from the territory of ignorance. Its inspiring motive, in short, is the desire for a rectification of the frontier in the interests of science. Material resources for the furtherance of such encroachments are not lacking. The globe is studded with observatories, variously and admirably equipped. Yet innumerable objects in the sidereal heavens remain neglected, mainly through inadvertence to the extraordinary interest of the questions pending with respect to them. In the following pages it has been sought to indicate some of these individually, and in their relations to the larger meanings of cosmical research. But this could be done effectually only from the vantage-ground of our actual acquirements; hence the book, although primarily designed to stimulate the progress of astrophysics, necessarily includes an account of its present state. Before attempting to add to our store of learning, we must realise what is already possessed.