An instrument for measuring trees, invented by Messrs. Duncombe and Whittel. It consists of a semicircle, divided into two quadrants, and graduated from the middle; upon the diameter there hangs a plummet for fixing the instrument in a vertical position. The principal use of it is for measuring the length and diameter of any tree perpendicular or oblique to an horizontal plane, or in any situation of the plane on which it rests; or of any figure, whether regular or irregular, and also the length and diameter of the boughs, by mere inspection. The inventors of it have calculated tables, annexed to their account of the instrument itself, by the help of which the quantity of timber in a tree is obtained without calculation, or the use of the sliding rule. The dendrometer, fitted to a theodolite, may be applied to measuring the heights and distances of objects accessible or inaccessible, whether situated in planes parallel or oblique to the plane on which the instrument is placed. It may be also used for taking all anglcs,whether vertical, horizontal, or oblique, in any position of the planes in which they are formed.