If you’ve ever dealt with orbital mechanics or sophisticated computer graphics, you’ve probably run across the math term quaternions. [Anyleaf] has a guide to the practical use of this math concept ...

THIS being the second volume of the reprint of a book that has become classical, and is known, by reputation at least, to all mathematicians, it is unnecessary to review it at much length. A ...

As in recent numbers of NATURE my views on analysis have been quoted, and not very correctly, I ask for space to state them more explicitly. I see truth in the quaternion analysis and in the vector ...