A round-up of some interesting posts on The Sceptical Chymist blog.

Endangered elements: platinum, helium and iridium are running out. Any others?

Add it up: how good, or bad, are chemists at maths?

Reactions: what made Jonathan Steed a chemist?

Pour some sugar on me: about Nature‘s glycochemistry and glycobiology Insight.

What’s the hardest of them all?: the hardest-ever material, but is it new?

And finally, of direct use to authors: 50 ways to write a (cover) letter, in which Nature senior editor Joshua Finkelstein provides some useful tips.