Level construction

Claim 1

A LEVEL COMPRISING AN ELONGATED FRAME HAVING PARALLEL FLAT TOP AND BOTTOM SURFACES, AND PARALLEL FLAT END SURFACES, SAID END SURFACES BEING PERPENDICULAR TO SAID TOP AND BOTTOM SURFACE, SAID FRAME INCLUDING A CENTRAL BODY MEMBER HAVING A TRANSVERSE OPENING THEREIN, A ROTOR MOUNTED IN SAID OPENING FOR ROTATION ABOUT AN AXIS DISPOSED TRANSVERSELY OF THE FRAME, A GRADUATED DEGREE SCALE ON EACH SIDE OF THE ROTOR FOR OBSERVATION FROM EITHER SIDE OF THE FRAME, A STATIONARY INDEX LINE ASSOCIATED WITH EACH GRADUATED SCALE, SAID ROTOR HAVING A WEIGHT INCORPORATED THEREIN FOR MAINTAINING A CONSTANT RELATIONSHIP TO A HORIZONTAL PLANE, THE TOP SURFACE OF SAID FRAME HAVING AN OPENING THEREIN IN ALIGNMENT WITH THE PERIPHERY OF THE ROTOR AND PROVIDED WITH A STATIONARY INDEX LINE, AND A GRADUATED DEGREE SCALE ON THE PERIPHERY OF THE ROTOR THEREBY ENABLING THE INCLINATION OF THE FRAME TO BE DETERMINED FROM EITHER SIDE OR THE TOP OF THE FRAME, SAID FRAME INCLUDING A PAIR OF SPACED LONGITUDINAL MEMBERS, AND A PAIR OF SPACED VERTICAL PARTITIONS, A SPIRIT LEVEL VIAL ASSEMBLY DISPOSED BETWEEN THE PAIR OF PARTITIONS, A SPIRIT LEVEL VIAL ASSEMBLY DISPOSED BETWEEN THE SPACED LONGITUDINAL MEMBERS, EACH ASSEMBLY INCLUDING AND HOUSING AND A BUBBLE VIAL MOUNTED THEREIN, AND MEANS MOUNTING EACH HOUSING FOR ANGULAR ADJUSTMENT ABOUT THE LONGITUDINAL AXIS OF THE ASSEMBLY, SAID MOUNTING MEANS INCLUDING A PAIR OF ADJUSTABLE SCREW-THREADED MEMBERS, A PARTIAL SPHERICAL RECESS IN THE INNER END OF EACH SCREW-THREADED MEMBER AND THE OUTER ENDS OF SAID HOUSING, AND A SPHERICAL SHAFT RECEIVED IN ALIGNED RECESSES FOR ENABLING ROTATION OF THE ASSEMBLY AND FRICTION LOCKING THEREOF IN ADJUSTED POSITION.