Request #43

 I am looking for a mystery book I read in the 80’s from the local library.  The book is probably older, maybe 50’s, 60’s, or 70’s.  Children find a scrap of metal.  They find out that years before a woman stole a hurricane lamp or a spirit lamp from a local shop keeper. When she tried to light it she set the building (it might have been a lighthouse) on fire.  Any help would be appreciated. Thank you!