(I do not know the reason of this rule, nor who made it.) And they chanted all the gloomiest songs they could think of.

And, of course, nothing happened.
So then Anthea said, 'I'm sure a magic fire ought to be made of sweet-smelling wood, and have magic gums and essences and things in it.' 'I don't know any sweet-smelling wood, except cedar,' said Robert; 'but I've got some ends of cedar-wood lead pencil.' So they burned the ends of lead pencil.

And still nothing happened.
'Let's burn some of the eucalyptus oil we have for our colds,' said Anthea.
And they did.

It certainly smelt very strong.

And they burned lumps of camphor out of the big chest.