[f. FIELD sb. + GLASS.]
1. A binocular telescope for use in the field.
1836. Wellington, Let., 8 Oct., in Stanhope, Conversations. I send you one of my field-glasses which used to be excellent.
1880. Ouida, Moths, I. i. 20. ‘It makes all the women with colour look vulgar,’ he said, after a prolonged gaze through a friend’s field-glass.
2. ‘A small achromatic telescope, usually from 20 to 24 inches long, and having from three to six joints’ (Ogilv.).
3. That one of the two lenses forming the eyepiece of an astronomical telescope or compound microscope, which is the nearer to the object glass.
1831. Brewster, Optics, xli. 340. A larger lens than any of the other two, called the field-glass.
1867. J. Hogg, Microsc., I. ii. 40. An amplifying lens … by which the field of view is enlarged, and is consequently called the field-glass.
