34 Mr. woulfe’s Experiments , See. 
fame fort of blue, though not fo good. Hence we may 
conclude, that the fait of the firft experiment, which 
was produced by three drams of fpar with acid of vitriol, 
contained thirteen grains of vitriol of iron. 
Pruffian blue, made without help of allum, contains 
nearly half its weight of iron. Hence, from the fore- 
going experiments, three drams of this fpar contain 
gr. viii. of iron, ^ j. and gr. xlix. of calcareous earth, and 
j. gr. iij. of the earth of fal catbarticus amarus , or per- 
haps fome other earth, which forms, with acid of vitriol, 
a foluble fait. 
The fpathofe iron ore being frequently found crvftal- 
lized like the foregoing new fpar, and having alfo a glofs 
on it, I was willing to try whether it had any affinity 
with it ; but by the following experiments it appears to 
be of a different nature, not containing any calcareous 
earth. 
The fpathoie iron ore diffolves almoft totally in acid 
of fait, and the folution is of a deep yellow colour. A 
folution of tartar of vitriol in water added to it caufes no 
precipitation ; and hence it is evident, that it contains no 
calcareous earth. Acid of vitriol treated with the fpa- 
thofe iron diffolves the whole of it, excepting a few dregs ; 
another proof of its containing no calcareous earth. The 
acid of nitre diffolves alfo this fpar, and the folution is 
colourlefs. 
