altho there is no persons opinion I would prefer to yours on any Invention of mine as none If favourable Could be more Useful to me, I should not have Ventured to trouble you, If the particular Situation in which I am placed had not renderd it Neccessary. A few days past I Enclosed the Instrument (I now Enclose to you) to a Mr Goolrick of Fredricksburg, he on returning it writes me amongst other things in the following words to wit “the Idea of the mapper I am Inclined is not a new one Mr Girrardin was at my house 6 or Seven years ago he lived at that time in the neighbourhood of Montecello and was Intimate with Mr Jefferson as Near as my recollection Serves me at So remote a period I think I was Informd that Mr Jefferson used Something Similar to your mapper in platting fields &C” as I Could Consciencously have Sworn that I believed I was the original Inventor of the Enclosed Instrument before the Receipt of this letter: I Cannot now do it untill I hear from you. altho I believe Mr Goolrick has mistaken Mr Girrardins description of your Instrument I have deemd it the Correct1 Course to Enclose it. may I ask the favour of you after Examining of it and If not your Invention to Say your opinion of it and If favourable2 whethr I may make that opinion Publick practical Surveyors here have born testimony to its usefulness. I have for many years platted by Latitude & departure instead of Course and distance. by this Means the distance was a Check upon my work. it occurd to me that an Instrument on the plan Sent would facilitate mapping as Neither protractor, Sweep, Scale,3 or Even dividers would be neccessary. after the mapping Sheet is prepared like the one Enclosed which by the by Should last a surveyor his life time as I have made dozens of maps on the same Sheet by drawing the outlines of the map with a black lead pencil when the map is prickd off on a Clean Sheet with a rubber the lines are rubbed out and the pricks Stopd by pressing on them the Sheet is ready for a new map. this Sheet Should be Carefully laid off4 and to prevent Blunders in Calculating the Contents of your map Each Inch Should be a red line as the map lies before you you may in a few minutes add up the Contents of your map. the mapper is on a scale of Forty poles to an Inch but may be made to any Scale, in useing this Instrument you map by the Latitude & departure of your Course and not by the Course and distance If your Latitude is north the angle of the Instrument is Upwards. If South downward the perpendicular of the Instrument is the Latitude and the Base the Departure it has occurd to me there is a possibility I am describing what you well know the thought has Stopt me your General Character assures me you will pardon this freedom