Descartes in 1637 published his works on geometry which firmly established the method of rectangular coordinates when used for mathematical formulas. Those who are interested in the history of graphic presentation will find the sequences well brought out in a paper of one hundred and thirtyfive pages by H. Gray Funkhouser, published in Osiris, Volume Three, Part One, 1937, available through the Carnegie Institution of Washington, D. C. Funkhouser dates the use of the coordinate field to astronomers and surveyors as far back as 140

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INTRODUCTION

B.C. when points in the earth's surface were located by means of their longitudes and latitudes. Oresme in 1350 in his Tractitus de Latitudinibus Formarum endeavored to represent graphically how an empirical curve might behave. As Funkhouser states, "If a pioneering contemporary had collected some data and presented Oresme with some facts to work on, we might have had statistical graphs four hundred years before Playfair."

Leonardo da Vinci antedated Descartes 77 years. Leonardo's genius in the natural sciences and as an engineer was so far in advance of his time that it would seem that he might have been familiar with rectangular coordinates. Recent examinations of his

notebooks, though not very conclusive, seem to indicate that in his experiments regarding gravitation, his records of the velocity of falling bodies were analyzed on a rectangular coordinate basis. See Volume M, Verso 40, Manuscripts of the Institute of France. He used horizontal distances to express time and vertical distances to show the space covered by falling balls when two were dropped together or one following the other. Leonardo, however, left no group to carry on his engineering works, which were little understood by his immediate contemporaries and successors. The American Statistical Association, formed in 1839, now celebrating its one hundredth anniversary, is the earliest specialized scientific organization in this country.