Paris: Didot, 1772. hardcover. xl. 474, (6)pp. 8vo, full, gilt decorated calf; lightly rubbed and worn (front hinge cracked, but sound; edgeworn; cornes bumped). Lyon: Perisse and Paris: Didot, Jnr., 1772. First Edition. Very good (+). very good.
First Edition of Janin's principal work containing an account of the first experiments with glasses of complementary colors before both eyes. (Hirsch). The author "noted the need for convex glass to enable one to see distant objects." (Chance). In the final section of this book (pp. 429-432) appears the first published account of hypermetropia. Blake 234. Wellcome III, 345. Waller 5116.