Explanation for constructing cylinder and helix forms, with four stunning illustrations. 2 leaves, each 8.25 x 6.25 inches, in acid-free mat and archival sleeves, 12 x 9 inches. The first leaf is matted single-side, the other with a double window to view the drawings on each side. Both mounted with mylar corners for easy removal and examination. Very Good condition with minor surface wear incurred by the original student while drafting. From a mid-19th century French student manuscript on architectural and mechanical drafting containing notes for computational and perspective drawing, studies on light and shade, reflection, etc.