Imagine winding the hour hand of a clock back from 3 o’clock to noon. Mathematicians have long known how to describe this rotation as a simple multiplication: A number representing the initial ...

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 ...

The Royal Irish Academy, the academy for the sciences and humanities for the whole of Ireland will vigorously promote excellence in scholarship, recognise achievements in learning, direct research ...

NATURE of December 15, 1887 (p. 145), which has lately reached me, contains a notice of a treatise on Quaternions, by Prof. Valentin Balbin, in which the reviewer alludes to the “slight alterations” ...