diffusion (dif-fu's hun)

The state of being diffused; the act of diffusing; the proce by which two liquids or two gases, when brought into contact with each other, gradually intermix until every part of one is in contact with some portion of the other. anodal d. See cataphoresis. circles of d. Circles of d. formed on the retina when a pencil of ray cuts the retina before or after coming to a focus, d. apparatus. See under apparatus, d. circles. See circles of d. d. coefficient. The amount of di olved substance which under constant conditions diffuses through a membrane in a unit of time. It varies with the temperature. d. electrode. See under electrode, d. of heat. The irregular reflection of heat rays from the surface of bodies. As in the case of light, the different thermal rays are diffused (or irregularly reflected) by certain bodies in different degrees, the thermal rays which are not so diffused being absorbed, d. of light. The irregular reflection of light rays from the surface of an unpolished body. Part of the rays falling upon such a body are absorbed, part are reflected in every direction, the wave length of the rays that are so reflected determining the color of the body. The general diffused brightne of daylight is due to the d. of light falling upon clouds, particles floating in the air, and terrestrial objects, d. stasis. See under stasis, d. tube. An instrument intended for the d. of gases. [Lat., diffusio.]