Of the light beame. cap. 43.
A Light beame is a bright streame of a bodye of lyght, by the which beame, lyght and shining doth his wor∣king, as Beda sayth. And some beame passeth straight forth, and commeth of the bodye of light, moouing by a straight line without blenching, and commeth to the middle point, and is called Perpen∣dicularis and Rectus: And some beame commeth of a bodie of lyght, and findeth a cleere body, and passeth not forth right, but sidelyng and blenching, and this blenching is called breaking of the beame. And such a light beame is called breaking of the Beame. And such a light beame is called Radius colleteralis, & Confractus. And the Sunne beame passeth straight foorth from the bodye of lyght, or blencheth aside, and méeteth with a bodye, that putteth and smiteth the light againwarde: and such a smi∣ting and putting is called bending of the beame: and such a Beame is called Radius reflexus, as the Authour of Per∣spectiue sayth. And so a Beame of light is moueable, and cleere, and bright, and rounde, and right of it selfe, and most conteined if it be of a straight Beame: and it happeneth sometime, that a light or bright beame is broken and shuft a∣side, or againeward, by the disposition of matter that it findeth and toucheth. Such a beame is closed in a hollowe clowde, and most worketh and maketh diuerse formes, coulours, shapes, and figures in the Clowde, or in the ayre, as it fareth in the coulours of the Raine-bowe, that is not else called, but entering of light beames into an hollowe clowde and wa∣tyre, as it is sayde libro Mecherorum: alwaye sodeinlye by moouing of beames that moue continuallye and sodeinlye, it happeneth that the ayre about is sette a fire: and namelye if the beames meete in the place of rebounding. For there the beames be gathered, and beat each other: and so they are cause why the ayre a∣bout is oft set a fire, as it fareth in Chri∣stall, and in Berrall. For if such a stone be set afore the Sunne, and put thereto, it shall set it on fire.