WHEN man invented the wheel, bearings were introduced into civilization and every machine since devised incorporates, in some form, means of sustaining a loaded member in motion by another fixed member. It is not surprising, therefore, that examination of bearings forms a high proportion of all engineering inspection and the phrase “to look at the bedding of the bearing” is probably one of the oldest in engineering practice. During recent years, particularly in the aircraft industry, developments have taken place in bearing design and bearing metals which require an inspection technique differing from conventional methods that served well when loadings were comparatively low and factors of safety high. Desirable clearances and surface condition of the earlier alloys will not answer at all well for some new bearing materials; while on the other hand defects such as minor cracks, which were very dangerous in white metal, have been proved by experience to have little or no effect on some heavily loaded lead bronze bearings.