What does the Time Traveller find that causes him and Weena to dance?

The TT finds matches.

At last, in one of the really air-tight cases, I found a box of matches. Very eagerly I tried them. They were perfectly good. They were not even damp. I turned to Weena. “Dance,” I cried to her in her own tongue. For now I had a weapon indeed against the horrible creatures we feared. And so, in that derelict museum, upon the thick soft carpeting of dust, to Weena’s huge delight, I solemnly performed a kind of composite dance, whistling The Land of the Leal as cheerfully as I could. In part it was a modest cancan, in part a step dance, in part a skirt-dance (so far as my tail-coat permitted), and in part original. For I am naturally inventive, as you know.