This chemistry wordoku spotlights a chemist who first proposed teaching through discovery lab work!

Solve this wordoku in the same way as a sudoku with letters instead of numbers (each of the nine letters in each row, column and nine-square cell). Once solved, one of the overall diagonals can be rearranged to give the surname of a 19th century chemist whose research focused on naphthalenes and who ‘ruled the Chemical Society with a rod of iron’ during the 18 years serving as its secretary, according to his 22-page obituary in the Journal of the Chemical Society.

This week’s letters are: A G M N O R S T W