an optical instrument used to detect small differences in two photographs of the same field or object by viewing them alternately, switching rapidly from one to the other.
[ 1925-30 ]
an optical instrument used to detect small differences in two photographs of the same field or object by viewing them alternately, switching rapidly from one to the other.
[ 1925-30 ]
Random House Webster's Unabridged English dictionary. Полный английский словарь Вебстер - Random House . 2012