248 Observations on Ignis Fatuus. 
With the phenomena exhibited in this instance, I have 
been accustomed to compare those exhibited in other in- 
stances, whether observed by myself or others ; and general- 
y, making due allowance for the illusion of the senses and 
the credulity of the imagination in a dark and misty night, 
(for it is on such nights that they usually appear,) I have 
found these phenomena sufficient for the explanation of all 
the fantastic tricks which are reported of these phantoms. 
They are supposed to be endowed with a locomotive pow- 
er. They appear to recede from the spectator, or to advance 
towards him. But this may be explained without locomo- 
tion—by their variation in respect to quantity of flame. As 
the light dwindles away, it will seem to move from you, and 
with a velocity proportioned to the rapidity of its diminution. 
Again as it grows larger, it will appear to approach you. 
If it expires, by several flickerings or flashes, it will seem to 
skip from you u, and when it reappears you will easily imagine 
that it has assumed a new position. This reasoning accounts 
for ther apparent motion, either to or from the spectator ; 
and I never could ascertain that they moved in any other 
direction, that is, in a line oblique Sr porpendiealar to that 
in which they first appeared. In one instance, indeed, 
thought this was the fact, and what struck me as more sin- 
guiar, the light appeared to move, with great rapidity, di- 
rectly against a very strong wind. But after looking some 
time, I reflected that I had not changed the direction of m 
eye at all, whereas if the apparent motion had been re 
I ought to have turned half round. The deception was oc- 
casioned by the motion of the wind itself—as a stake stand- 
ing ina rapid stream will appear to move against the current. 
a common notion that the ignis fatuus cannot be ap- 
roached, but will move off as rapidly as you advance. This 
characteristic is mentioned in the Edinburgh Encyclopedia. 
It is doubtless a mistake. Persons attempting to approach 
them, have been deceived perhaps as to their distance, and 
finding them farther off than they imagined, have proceeded 
a atte way and given over, under the impression that pursuit 
An acquaintance of mines plain man, told me 
he ae stole up close to one, and caught it in his hat, as 
he t;—‘“‘and what was it?” I asked. “It was’nt 
nothin.”* On looking into his hat for the “ shining jelly,” it 
elias: 
aT T ee te ey 42 fat 1 cnr 2 OR ee Fad. 
S bs r a 
