BONNYCASTLE, John. An Introduction to Astronomy. In a series of letters, from a preceptor to his pupil, London: J. Johnson, 1787, 8°, second edition, engraved frontispiece and 19 plates, some folding (a few spots), contemporary calf (lacking front cover, worn) -- James FERGUSON. Astronomy explained upon Sir Isaac Newton's Principles, and made easy to those who have not studied mathematics, London: T. Longman, B. Law [and 15 others], 1794, 8°, ninth edition, folding engraved frontispiece and 17 folding plates (one plate with clean tear, first few lower corners dampstained, a few spots), contemporary calf (lacking front cover, worn). [Wallis 75.01; Babson (lists only the 3rd ed.): "Ferguson ... makes one of the earliest and most successful attempts to explain Newtonian ideas in popular terms"] With Samuel Vince's The Principles of Astronomy: Designed for the use of students in the University, vol. IV of James Wood and Samuel Vince's The Principles of Mathematics and Natural Philosophy (Cambridge, 1799, lacking half title) and one other (defective). (4)