h2g2 The Hitchhiker's Guide to the Galaxy: Earth Edition

I was rereading Terry Pratchett's 'The Fifth Continent' in the bath last night when two things occurred to me:
1) I shall have to stop taking baths when alone in the house. Arthritic bones mean it takes nearly ten minutes to get out afterwards and it feels dangerous. So, although loth to give up a minor pleasure of 60 years standing, I shall have to save the very splendid bath salt stuff my daughter in law sent me until she is over here again.
2) Surely Terry Pratchett knows the word Petrichor for the smell of ground after the rain? The last couple of pages hinge on a formerly useless word being passed from one aboriginal to another until it finally rains and there is a use for it.
So I looked the word up and it was invented by a couple of Australian scientists about 30 years ago. Perhaps Pratchett is pulling another of his double bluffs as the book is (sort of) about Australia. A minor pleasure of reading him is getting to feel superior when you recognise the references.