The Latin phrase pons asinorum (asses' bridge) is used for something that is difficult for beginners, but quite simple once you've learned it. It's the nickname of the fifth proposition of Book I of Euclid's Elements: "In isosceles triangles the angles at the base are equal to one another, and, if the equal straight lines… Continue reading Pons asinorum
Bone skates
The first ice skates were made from the leg bones of animals. Skaters simply stood on them (tying them on was optional) and pushed themselves along with metal-tipped poles. The skater in the picture is using what seems to have been the most common technique: pushing with one pole between the legs. Two poles were… Continue reading Bone skates
Aims & scope
As this is a new blog, I suppose I should describe its aims and scope.