a. [f. as prec. + -AL.] Relating to a mirror or to reflexion; = prec. Hence Catoptrically adv.
1696. Phil. Trans., XIX. 215. The Power of Catoptrical or Dioptrical or Cata-dioptrical Machines. Ibid. (1754), XLVIII. 622. Philosophers began to increase their catoptrical experiments.
1819. H. Busk, Tea, 63. By catoptrical devise survey Stars.
1870. Eng. Mech., 501/3. It may be used catoptrically.
