Page:Carroll - Euclid and His Modern Rivals.djvu/182



§ 2.

Nie. I lay before you An Elementary Treatise on Plane and Solid Geometry by, A.M., Perkins Professor of Astronomy and Mathematics in Harvard University, published in 1872.

Min. As I have already considered, at great length, the subject of direction as treated by Mr. Wilson, I need not trouble you as to any matters where Mr. Pierce's treatment does not materially differ from his. Is there any material difference in the treatment of a straight line?

Nie. He has a Definition of direction which will, I think, be new to you:—

Reads. P. 5. § 11, Def. 'The Direction of a Line in any part is the direction of a point at that part from the next preceding point of the Line.'