The discovery in recent years of vast deep oceanic currents running in a direction contrary to those at the surface provides additional evidence of our need for instrumental means to obtain accurate data on subsurface waters, particularly in little-known oceanic areas where pioneer lowerings are to be made. A description is given of a prototype messenger-operated wire-angle gauge which, used intermediately between reversing bottles, can furnish information on the direction of slope of the hydrowire and its actual degree of obliquity at a number of points. It is only the latter, of course, which can be computed from results obtained when unprotected reversing thermometers are used with the pressure-resisting type.