A method of logging a wellbore comprises drilling a first wellbore to a depth using a drilling rig and drilling a second wellbore to a depth using the drilling rig. Light of selected wavelengths is passed through blood or body tissue and the transmitted or reflected light is detected and the detected signals can be electronically compared and manipulated to provide the non-invasive, continuous and quantitative display of a patients blood urea, blood osmolarity, plasma free hemoglobin and tissue water content. The sliding bearings are composed of bearing halves bisected at a parting surface located on a flat plane, substantially orthogonal to the direction of the maximum pressure of the oil films, formed of the lubricating oil in the clearances. Sensors mounted on the linkage assembly generate force-indicating signals representing one or more of the user force.