"He could not have been more delighted if he had discovered the gold mine."
Is it means "When he discovered the gold mine, he was the most delighted."
Or "There is something more delighted for him than finding a gold mine."
Pls explain the grammar for it, thanks!!~
Thanks for your explanations~
I accept Phil's advice to find the context:
Preceding part of the text is saying about Sherlock Holmes find test results of reagent.
And refer to Chris, I tried to understand as below.
" Holmes did not discovery a gold mine, but he find the test results of reagent. For him, finding test results was more delighted than discovering a gold mine."
He could not have been more delighted if he had discovered the gold mine."
You were closest on your first guess.
The sentence means that the person is comparably as happy as if he had discovered the gold mine. The writer seems to be talking about a specific gold mine, otherwise they would have put "a" in place of "the" (gold mine). Often the word, "himself" is put at the end of sentences structured like this. "He could not have been more delighted if he had discovered the gold mine himself."
You might also think of it as saying, "It was impossible for him to be happier, even if he had discovered the gold mine."
Hope that helps!