Page:American Journal of Mathematics Vol. 2 (1879).pdf/7

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The Pascal Hexagram.

By Miss Christine Ladd, Johns Hopkins University.

I wish to propose a new notation for the lines and points connected with the Pascal Hexagram, to give a brief account of the discoveries of Veronese on the subject and to develop a few additional properties of the figure.

I.

The vertices of the hexagon inscribed in the comic, are the lines tangent to the conic at these vertices respectively are In general, a large letter will represent a point, a small letter a line. Lines joining vertices of the inscribed hexagon are called fundamental lines; intersections of sides of the circumscribed hexagon are called fundamental points. The intersection of the two fundamental lines is called the line joining two fundamental points, is called It is evident that is the pole of There are points and lines The Pascal line obtained by taking the vertices of the hexagon in the order is called It passes through the points Similarly, the intersection of the lines is the Brianchon point of the hexagon the pole of

The three Pascal lines which meet in a Steiner point are (Salmon's Comic Sections, 5th ed., note, p. 361) We shall call the Steiner point in which they meet In this symbol, the relative cyclic order of the letters in each group of three is all that it is necessary to observe; for instance, and are the same as Given a point, the lines through it are obtained by taking one group of three in a fixed order for the odd letter and permuting cyclically the other group of three for the oven letters. The Pascals which pass through the conjugate point are and the symbol of that point is hence two

Vol. II—No. 1.
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