E 70 ] 
oTi the agriculture of such parts of Europe as I hare' 
yet seen ; which, however, I shall do, I hope in 
time to submit to the consideration of our society , 
for useful arts, who are neither out of my mind, 
nor of my heart, and with whom I hope ere long to 
interchange observations, and to reduce to practice 
in my native land, whatever I may be enabled to 
learn in a foreign one. The subject of this letter 
appears to me of sufficient importance to call for 
immediate attention, as it may lead to experiments 
and deductions that may be found very useful to our 
common country. 
In' an excursion that I lately made into Flanders, 
i observed at some distance from the road, several 
large beds oF earth that appeared to me to emit 
smoke and flame, which two men were tending. I 
stopped the post-chaise and went to examine it ; I 
found that it was pyrites, sufficiently impregnated- 
with sulphur to burn when dry : This was layed 
into beds, and fire set to it; they endeavored to ex¬ 
tinguish the fire when the ashes was red, if it burnt- 
longer it became black, and the quality of it was 
not so good. This earth so burnt was easily reduced 
to powder by a wood nlallct, and in this state was 
carried upon the backs of asses forty and fifty miles 
as a manure, and v/as used particularly for grass, 
at the rate of about six bushels the acre. The seed 
grain was also covered with it as with gypsum in 
our country; this circumstance induces’a belief that 
the sulphuric acid is both in this and in the gypsum 
