These pages are my HTML versions of text ripped out of PDF files made by using an optical character recognition on Tait's old text. The digitization was contributed to the Internet Archive by U. Cal. Berkeley,
Of the body chapters, only chapter IV is really completed. This is extremely time-consuming, and how to proceed is often unclear.
As to why I would do this, well, there are several explanations (none of which stand as reasons). One is, I'm interested in the topic of quaternions. Also, I find this historical train-wreck of the quaternion "method" quite fascinating, and I think that its study could be instructive to present-day mathematicians. Another old hobby of mine is the use of HTML to display mathematics; this book provides many typographic challenges to my methods.