Ebook: Lectures on Quaternions

Lectures on Quaternions: Containing a Systematic Statement of A New Mathematical Method; of which the principles were communicated in 1843 to The Royal Irish Academy; and which has since formed the subject of successive courses of lectures, delivered in 1848 and subsequent years, in The Halls of Trinity College, Dublin: with numerous illustrative diagrams, and with some geometrical and physical applications.

https://en.wikipedia.org/wiki/Quaternion

Quaternions are the original foundation of Vector Analysis/Calculus, using vectors i, j, and k.