* 
246 Observations on Ignis Fatuus. 
evidence of the correctness of the results here given; the 
details I am —_—, to omit, as they would, obviously, 
extend this communication to too great a len 
One alin: or 231 cubic inches, of this water, when first 
taken from the well, contains 
Muriate of soda, - grains 297.3 
Hydriodate of soda, =: Hie RES ai SST Ss . 
Carbonate of soda, = - - - - 19.21 
Carbonate of lime, - - - 92.4 
Carbonate of magnesia, - - - 23.1 
Oxide of iron, - - - - 5.39 
grains 440.4 together 
with a minute quantity of silica and alumina, probably 0.6 
of a — making the solid contents of a gallon amount to 
A441 gra 
Gehivie ante gas, oil ssi 316 cubic inches. 
Atmospheric air, wilaeretee cette 4 
Gaseous contents in’a gallon, 0 cubic inches. 
It may be proper to observe, that the se was extricated 
from the water, by the application of heat, but was kept in 
the poet at the temperature of 60°, and under a pressure 
of the atmosphere, — by the mercury in the barome- 
ter emia at 29.5 es. A part of the atmospheric air 
was undoubtedly Shinined from the tube used to conduct the 
gas to the receiver. 
Art. V.—Observations on Ignis Fatuus; by Rev. Joun 
MitTcHELL, 
Tose luminous appearances, which are —. called 
“ Will-o’the-wisp” and * Jack-a-lantern,” have bee alike 
the object of vulgar superstition and philosophical curiosity ; i 
and notwithstanding all attempts to apprehend and subjec 
them to examination, they are not much more the raabjetls of 
knowledge now than t they were centuries ago. They are 
still but an ignis fatuus to the philosopher, and a thing of 
s the credulous. 
“Twas myself, ee familiar with these appearances ; 
oo of frequent occurrence near my father’s residence, 
owing, probably, to the proximity of extensive wet grounds, 
over which they are usually seen. The house stood upon @ 
