An Old Curiosity...my father's Abney Level

The Abney level was invented by Sir William de Wiveleslie Abney (Born 24 Jul 1843 Died 3 Dec 1920) who was an English astronomer and chemist best known for his pioneering of color photography and color vision. Abney invented this instrument under the employment of the School of Military Engineering in Chatham, England in the 1870s. It is described by W. & L. E. Gurley as an English modification of the Locke hand level, noting that it gives angles of elevation and is also divided for slopes, as 1 to 2, 2 to 1, etc. Since the main tube of this instrument is square, it can be applied to any plane surface. The clinometer scale is graduated to degrees, and read by vernier to 5 minutes. This one was used for surveying, in the laying out and extension of tea estates in Sylhet in the 1920s.