Transpaˊrent Bodies [with Philosophers]

or diaphanous bodies, are such whose pores are all right, and nearly perpendicular to the plane of their surface, so as to let the rays of light pass freely through them, without being refracted; whereas the pores of opacous bodies are in a crooked oblique position, by which means the beams of light cannot pass freely through them, but are variously refracted and lost.