{Very faint Violet rays falling on Black make it appear {Violet-black. ” ” White ” Violet. ” ” Violet ” Deeper Violet. {Red-violet ” ” Red ” {Purple. ” ” Orange ” Light Red. {Brown, with a ” ” Yellow ” {very slight tint {of Red. ” ” Green ” Light Purple. {Fine Blue ” ” Blue ” {Violet. {Deep Blue ” ” Indigo ” {Violet. 267. It is understood that to represent the preceding phenomena exactly, we must take into account the facility with which coloured light penetrates every kind of glass, the more or less intense colour of the stuff, and the kind of scale to which the coloured stuff and that of the transmitted coloured light respectively belong. 268. These observations were made by partially exposing coloured stuffs to the sun’s rays transmitted through coloured glasses. The portion of stuff not exposed to these rays, was lighted by the direct light of the sun. The portion of stuff which received the action of the coloured rays being exposed to diffused daylight, reflected also rays of that light which it would have reflected in case it had been protected from the influence of the rays transmitted to it through coloured glasses. 269. II. Modifications produced by two lights of different intensity. 270. 1. The modification by the light of the sun falling upon one part of the surface of a coloured body, while the other part is enlightened by diffused daylight. 2. The modification produced when two parts of the same object are unequally illuminated by diffused daylight. _An object lighted partly by the sun, and partly by diffused daylight._ 271. To observe this kind of modification properly, let us expose to the sun a square piece of stuff A B, two and a half inches broad (Plate I., fig 4) and place in the middle a piece of black wire _f, fʹ_; then put parallel to this, and in the middle between A and B, two wires _e, eʹ_ and _g, gʹ_, of about three-tenths of an inch in width. The extremity _gʹ_ is fixed upon a perpendicular plane, so high, that all the part B _f, fʹ_ may be in shadow. 272. 1. _If the stuff is red_, the lighted portion A is more orange or less blue than the part B, which is in shade; and the portion _a_ is more orange than the portion _aʹ_, as the portion _b_ is bluer than the portion _bʹ_.