3 optical squares, a spirit level, 2 magnetic... Lot 498

3 optical squares, a spirit level, 2 magnetic needles and a plumb. 1. optical square or "équerre à réflexion". Brass, mirror and wood, 5 x 6 x 13 cm. 19th c. - 2. Optical square. Brussels, A. Beaulieu, 19th c. Brass, 10,7 x 2,2 x 2,4 cm. Signed and numbered "180". Leather box. - 3. miniature optical square. Metal, 4.3 cm. Leather pouch. - 4. brass spirit level. 14 cm. In box. - 5-6. 2 magnetic needles fixed in a case with diametrically opposed reference lines. Brass, 14,7 cm and wood, 16 cm. - 7. plumb. Brass, ca. 7 cm with rope (new?).