Thank you for checking out this book by Theophania Publishing. We appreciate your business and look forward to serving you soon. We have thousands of titles available, and we invite you to search for us by name, contact us via our website, or download our most recent catalogues. The present volume is chiefly intended for those of my young friends who have read, and been interested in, the Fairyland of Science. It travels over a wide field, pointing out a few of the marvellous facts which can be studied and enjoyed by the help of optical instruments. It will be seen at a glance that any one of the subjects dealt with might be made the study of a lifetime, and that the little information given in each lecture is only enough to make the reader long for more. I hope some eager minds may be thus led to take up one of the branches of science opened out to us by magic glasses; while those who go no further will at least understand something of the hitherto unseen world which is now being studied by their help. The two last lectures wander away from this path, and yet form a natural conclusion to the Magician's lectures to his young Devonshire lads.