Agricultural computer

Claim 1

AN AGRICULTURAL COMPUTER FOR USE IN COMPUTATIONS RELATING TO THE SPREADING OF MATERIAL OVER A FIELD OF KNOWN DIMENSIONS; SAID COMPUTER COMPRISING A BASE PLATE INCLUDING A SUBSTANTIALLY CIRCULAR PORTION, AND A CO-PLANAR PORTION PROJECTING FROM SAID SUBSTANTIALLY CIRCULAR PORTION FOR RECORDING AND SUBSEQUENT ERASURE OF THE RESULTS OF SAID COMPUTATIONS; A NUMERICAL SCALE DISPOSED CIRCUMFERENTIALLY ALONG ONE SURFACE OF SAID SUBSTANTIALLY CIRCULAR PORTION ADJACENT THE PERIPHERY THEREOF; SAID SCALE HAVING INDICIA DESIGNATING LENGTH OF FIELD IN UNITS OF DISTANCE IN UNIFORM INCREMENTS THEREALONG; AN OPAQUE DISK ROTATABLY MOUNTED ON SAID SUBSTANTIALLY CIRCULAR PORTION PARALLEL AND ADJACENT TO SAID ONE SURFACE THEREOF AND CONCENTRIC THEREWITH; SAID DISK HAVING A DIAMETER SMALLER THAN THE DIAMETER OF SAID SUBSTANTIALLY CIRCULAR PORTION TO EXPOSE SAID SCALE; A PLURALITY OF FURTHER SCALES CIRCULARLY DISPOSED INN CONCENTRIC RELATION AT RADIAL INTERVALS ALONG SAID ONE SURFACE OF SAID SUBSTANTIALLY CIRCULAR PORTION; SAID FURTHER SCALES HAVING INDICIA GRADUATED RESPECTIVELY IN UNITS OF AREA AND IN NUMBER OF STRIPS OF PREDETERMINED WIDTH FOR A PREDETERMINED FIELD LENGTH, AT ALTERNATE ONES OF SAID RADIAL INTERVALS; A FIRST PLURALITY OF RADIALLY ALIGNED WINDOWS IN SAID DISK, EACH HAVING A DESIGNATION INDICATIVE OF A GRADUATE UNIT OF STRIP WIDTH; A FIRST INDEX MARK ADJACENT THE PERIPHERY OF SAID DISK AND DISPOSED RELATIVE TO SAID FIRST PLURALITY OF WINDOWS SUCH THAT ALIGNMENT OF SAID INDEX MARK WITH ANY ONE OF SAID INDICIA OF SAID FIRST MENTIONED NUMERICAL SCALE EXPOSES INDICIA DESIGNATING UNITS OF AREA, AT SAID FIRST PLURALITY OF WINDOWS, CORRESPONDING TO RESPECTIVE STRIP WIDTHS FOR THE SELECTED FIELD LENGTH ADJACENT SAID INDEX MARK; A SECOND PLURALITY OF RADIALLY ALIGNED WINDOWS IN SAID DISK, EACH HAVING A DESIGNATION INDICATIVE OF A GRADUATE UNIT OF STRIP WIDTH; EACH OF SAID SECOND PLURALITY OF WINDOWS BEING RADIALLY OFFSET FROM EACH OF SAID FIRST PLURALITY OF WINDOWS BY ONE OF SAID RADIAL INTERVALS; A SECOND INDEX MARK ADJACENT THE PERIPHERY OF SAID DISK AND DISPOSED RELATIVE TO SAID SECOND PLURALITY OF WINDOWS SUCH THAT ALIGNMENT OF SAID SECOND INDEX MARK WITH ANY ONE OF SAID INDICIA OF SAID FIRSTMENTIONED NUMERICAL SCALE EXPOSES INDICIA REPRESENTING NUMBER OF STRIPS OF THE RESPECTIVELY DESIGNATED STRIP WIDTH, AT SAID SECOND PLURALITY OF WINDOWS, FOR THE SELECTED FIELD LENGTH ADJACENT SAID SECOND INDEX MARK.