Model of a cylindroid, 1895-1900.
© Science Museum / Science & Society Picture Library
Detail of a wire model of a 'cylindroid' by Howard Grubb, Dublin, in a bras glazed cylindrical case on a wooden base. The model was made on the instructions of Robert Stawell Ball who wrote the definitive work 'A treatise on the Theory of Screws' in 1900. Thomas Grubb, and later his son Howard, ran a firm of telescope makers in Dublin from the 1830s until the 1920s.