Can you discover ‘Isaac Newton’s hidden condition (4)’?

Solve GPE Scientific’s puzzle and you could win £50

In partnership with GPE Scientific, we’re hiding a chemistry term across six cryptic crosswords – if you solve all six and collect the letters in the yellow squares (click ‘Show ninas’ above to reveal them), you could win one of 10 £50 prizes. This is the first of the six puzzles, so check back every month for the next and for more information on how to enter the competition.