This is a translation of 'Essai sur le calcul des quaternions de M. W. Hamilton' by Alexandre Allégret, available from www.e-rara.ch. Quaternions is a difficult subject, and this essay is a difficult essay. You will need at least a high level of competence in calculus to understand this essay, plus a willingness to learn the difficult topics of spherical geometry and the geometry of surfaces and curves. This essay is divided into three sections:
- 1. Basic principles.
- 2. The geometric interpretation of the quaternionic symbols, which leads into spherical trigonometry.
- 3. The analysis of curves and surfaces.
The author uses quaternions to establish already known formulae in these fields. Notwithstanding the advanced level of this essay, it is also a very humane essay, since the author begins with elementary principles before leading into the advanced analysis.
Note: Java source code for a quaternion calculator is available from home.lizzy.com.au/jeremy.staines/index.html See: Quat_Calc.java See also: Some_notes_on_Quaternions.pdf