Micrometric grid calculator

Claim 1

A MICROMETRIC GRID CALCULATOR COMPRISING A BASE FOR MOUNTING ON A TRIPOD HEAD; AN ARC, CALIBRATED IN DEGREES, SUPPORTED BY THREE EXTENSIONS OR ARMS OF THE SAID BASE; A SUB-GRID FRAME ATTACHED TO SAID BASE BY A TONGUE AND GROOVE SLIDE TO PERMIT UNIDIRECTIONAL MOVEMENT RELATIVE TO SAID BASE; A SEMICIRCULAR MOVABLE GRID, WITH GRID LINES INSCRIBED ON THE FACE THEREOF .100 OF AN INCH APART IN TWO DIRECTIONS AT RIGHT ANGLES, ATTACHED TO THE SAID SUB-GRID FRAME IN SUCH A MANNER AS TO PERMIT MOVEMENT RELATIVE TO SAID SUB-GRID FRAME AND SAID BASE IN A DIRECTION AT RIGHT ANGLES TO THE DIRECTION OF MOVEMENT OF THE SAID SUB-GRID FRAME RELATIVE TO THE SAID BASE; A MOVABLE ARM, WITH PROXIMAL END PIVOTALLY ATTACHED TO AN EXTENSION OF THE SAID BASE AND ITS DISTAL END EXTENDING BEYOND THE OUTER EDGE OF THE SAID ARC, A TRANSPARENT SLIDE, ATTACHED TO SAID ARM WITH TONGUES AND GROOVES SO AS TO PERMIT LONGITUDINAL MOVEMENT OF THE SAID SLIDE RELATIVE TO THE SAME ARM, SAID TRANSPARENT SLIDE BEING CROSS MARKED WITH INDEX LINES SPACED .1000 OF AN INCH APART; A MICROMETER ON THE DISTAL END OF THE SAID SLIDE TO PROVIDE MICROMETRIC MEASUREMENT OF THE MOVEMENT OF THE SAID SLIDE RELATIVE TO THE SAID ARM; TWO MICROMETERS AT OPPOSITE ENDS OF THE MOVABLE GRID TO PROVIDE MICROMETRIC MEASUREMENT OF THE HORIZONTAL MOVEMENT OF THE SAID GRID RELATIVE TO A SELECTED INDEX MARK ON THE SAID SLIDE OF THE SAID MOVABLE ARM; AND A FOURH MICROMETER AT THE MIDDLE OF THE STRAIGHT SIDE OF THE SAID SEMI-CIRCULAR GRID TO PROVIDE MICROMETRIC MEASUREMENT OF VERTICAL MOVEMENT OF THE SAID MOVABLE GRID RELATIVE TO THE SAID SELECTED INDEX MARK ON THE SAID MOVABLE ARM.