Elements of Dynamic is a book published by William Kingdon Clifford in 1878. In 1887 it was supplemented by a fourth part and an appendix. The subtitle is "An introduction to motion and rest in solid and fluid bodies". It was reviewed positively, has remained a standard reference since its appearance, and is now available online as a Historical Math Monograph from Cornell University.
On page 95 Clifford deconstructed the quaternion product of William Rowan Hamilton into two separate products of two vectors: vector product and scalar product. This separation of the quaternion product into two was followed by J. W. Gibbs in his development of vector analysis, first in a pamphlet acknowledging Clifford's Kinematic,[1] and later in a textbook published by Yale University, called Vector Analysis. He apparently remained unaware of Clifford's seminal paper on the unification of these two products into what he termed a geometric algebra.[2]
Elements of Dynamic was the debut of the term cross-ratio for a four-argument function frequently used in geometry.
Clifford uses the term twist to discuss (pages 126 to 131) the screw theory that had recently been introduced by Robert Stawell Ball.
- ^ J. W. Gibbs (1884) Preface to Elements of Vector Analysis
- ^ Clifford, William (1878). "Applications of Grassmann's extensive algebra". American Journal of Mathematics. 1 (4): 350–358. doi:10.2307/2369379. JSTOR 2369379.