🔖 This antiquarian volume contains a treatise on mathematical instruments, including most of the instruments employed for drawing, for assisting the vision, in surveying and levelling, in practical astronomy, and for measuring angles of crystals. The methods of testing, adjusting, and using the instruments are concisely explained and illustrated where appropriate. The chapters of this book include: Wholes and Halves, Proportional Compasses, Triangular Compasses, Drawing Pen, Road Pen, Prickling Point, Straight Edge, Scales of Equal Parts, Protracting Scales, Gunter's Lines, The Plain Scale, et cetera. This book was first published in 1856, and is being republished now complete with a new introduction on the subject.