Throughout her lifetime, Margaret Bryan (fl.1795-1816) ran several schools for girls. Although science and maths were not usually considered suitable subjects for young women, Bryan was convinced that the use of one's reasoning faculties was all but a religious obligation. She taught across a huge range of topics, including optics, trigonometry and the history of astronomy. This book is a collection of ten of her lectures and was first published in 1797. Largely non-technical and written for those without a thorough knowledge of mathematics, the lectures explain contemporary science as simply as possible, using everyday experiments and clear diagrams. From astronomical predictions for the flooding of the Nile in Ancient Egypt to Newton's theory of the aether, the material covered is still readable and fascinating today, and represents a remarkable example of female scholarship long before the acceptance of the first woman into the Royal Society.