This is a boxwood slide rule, double sided with two slides (one for each side - themselves with scales on either side) designed for tradesmen. Under the slide, on the main body, are scales which help with calculating annuities. One narrow edge has a 12 inch ruler, the other has a table for calculating the weight of squares, cylinders, and globes of cast brass, bricks, copper, cast iron, wrought iron, lead, linseed oil, marble, proof spirit, salt, tallow and water. One slide has trigonometric function scales.
