I 
( ) 
ed to confult my curious and ingenious Friend, Sir 
Tho. Derehaw^ about the Phoenomenon^ being in- 
formed, that thofe Ignes Fatui are common in all the 
Itahan Parts, j^iut of the Pyrmfta, or Ftre-ftes, 
he laith, Pie never ^ ohferved any Jlich E fe^fs, aP 
though there Is an tmmenfe Number of them ///June 
and July. He^ faith moreover, that thefe Pyraujf^ 
are called Lticctole^ i. e. Small Lights^ and that they 
are not ,the Farfalls ( as Mr. Ray thought ) which 
zxt Butter -Jit es, ;i. , 
But I have good Reafon to think, that Infers are 
not concerned in the /gnes Fatui, from the followino^ 
Obfervations ; the Firft of which I made my felf, and 
the others I received from Italy, by the Favour of 
Sir Tho. Dereham. 
My own Obfervation I made at a Place that lay 
in a Valley between Rocky Hills, which I fufped: 
might contain Minerals, in fome Boggy Ground near 
the Bottom of thofe Hills. Where, feeing one in a 
calm, dark Night, with gentle Approaches I got up by 
Degrees within two or three Yards of it, and; viewed 
it with all the Care I poflibly could. I found it frisking 
about a dead Thiftle growing in the Field, until a 
fmall Motion of the Air (even fuch as was caufed on- 
ly by the Approximation of my felf) made it skip to 
another Place, and thence to another, and another. 
It is now about fifty-five Years fince I faw this Phce- 
nomenon, but I have as frefia and perfed an Idea of 
it, as if it was but of a few Days. And as I took it 
then, fo I am of the fame Opinion now, that it was 
a 'fired' Vapour. 
The Male-Glowonns I know emit their fliining 
Light, as they flyj by which Means they difcover 
and 
