Abstract: A method and apparatus are described for logging an open hole well, or the like, for the purpose of determining the presence of a given constituent in the various substrata and for providing means and method for determining the degree of presence of the constituent in a given formation where it has been located. A probe capable of being lowered into a bore hole includes a color video camera, a particular form of light source, apparatus for carrying and issuing a spray of cleaning substance and apparatus for carrying and issuing a chemical which facilitates the analysis of the degree of presence of the constituent. The probe is lowered to the bottom of the bore hole and then raised to a desired level. A cleaning jet sprays the surface to be inspected. The cleaned surface is then illustrated with light having a frequency in a predetermined frequency range and the reflected light is directed to the camera. The video signal is conducted to the surface where it is displayed.