This list started with “X is a cross”, by which Tom Chivers remembers which is the X-axis and which is the Y on a graph. “My son’s been told ‘Y to the sky’ which seems to work as well,” said Funkadelic Horse. Thanks to Stephen Tall and Xlibris1 for drawing this to my attention.

1. How I wish I could calculate pi. The number of letters gives the first seven digits of pi: 3.141592… Thanks to Andrew Ruddle, who said piphilology is the word for the invention and study of mnemonics for pi.

2. My Very Easy Method Just Speeds Up Naming Planets. From Marcus, which we need because no one can remember if Uranus or Neptune comes first.

3. Every Good Boy Deserves Favour. “Not only the mnemonic for the notes on the treble clef, but a Tom Stoppard play,” said Peter Warner.

4. Able Bodied Seamen Catch Hairy Pirates. For the (surnames of the) wives of Henry VIII. Nominated by Tom Joyce. Everyone knows how to remember their fates – “divorced, beheaded, died, divorced, beheaded, survived” – although pedants like to point out that Anne of Cleves also survived him, and lived longest.

5. Dear Kate, Please Come Over For Great Spaghetti. The polite version of the one for remembering the order of taxonomy in biology: Domain, Kingdom, Phylum, Class, Order, Family, Genus, Species. Thanks to Chris Jones.

6. The short word means left, the longer means right. Left right; port starboard; red green (lights). Surprisingly useful nautical and aeronautical tip from Xlibris1.

7. Hear! Hark! Listen BBC News On Friday Night. News Maybe About Silly Pupils Smashing Chemical Apparatus. Peter Elliott wrote: “Over 40 years ago my chemistry teacher, John Blythe, taught us this for the first 18 elements in the periodic table, which translates as: H, He Li, Be, B, C, N, O, Fl, Ne, Na, Mg, Al, Si, P, S, Cl, Ar.”

8. Homes. For the Great Lakes: Huron, Ontario, Michigan, Erie, Superior. Thanks to John Peters.

9. Red and yellow, kill a fellow; red and black, poison lack. “Taught in school in Texas about 1962 to distinguish the banding of venomous coral snakes from non-venomous snakes of similar appearance,” said Bill Detty, who also offered “Leaflets three, let it be,” which helps identify poison ivy.

10. Stalactites hold on tight; stalagmites might reach the roof one day. Eliot Kane thinks he got it from a Famous Five story, but it is probably older even than that.

These days, few people need trigonometry, but Martin Cable still remembers: “Some Officers Have Curly Auburn Hair Til Old Age.” Sine = Opposite Over Hypotenuse; Cosine = Adjacent Over Hypotenuse; Tangent = Opposite Over Adjacent. Roger Stevenson remembers a different version: “Some Of Harry’s Cats Are Heavier Than Our Armadillos.”

Now all I need is a mnemonic to remember how to spell mnemonic.

Next week: Proposed unions of countries, such as Britain and France in 1940, urged by Churchill as an alternative to French surrender to the Germans

Coming soon: Famous schoolmates, such as Alan Sugar and Marc Bolan, who went to the same school in Hackney

The book of Top 10s, Listellany, is still available for £4.74 as an e-book