Mr, Davy’s Lecture on some 
plunged in pure water in a platina crucible ; and the level of 
the fluid preserved a few lines below the surface of the cubes ; 
two platina wires were introduced into the holes, which were 
filled with pure water. The disengagement of gas, when the 
wires were connected with the battery of i oo, proved that the 
sulphate of strontites was sufficiently porous to form a proper 
conducting chain. The results were much longer in being 
obtained in this experiment than in the last: some time 
elapsed before a sensible effect could be perceived ; but the 
termination was similar. In 30 hours the fluid in the cavity 
containing the negative wire had gained the property of pre- 
cipitating solution of sulphate of potash ; and the presence of 
sulphuric acid in the other cavity was evident from its effect 
upon solution of muriate of barytes. 
I made an experiment upon fluate of lime under like cir- 
cumsances ; but the crystallized fluate not being equally 
permeable to moisture, the two cavities were connected by 
moist asbestus. This decomposition was likewise very slow ; 
but in the course of two days a pretty strong solution of lime 
was obtained in one tube; and an acid fluid in the other, 
which precipitated acetite of lead, and left a spot upon the 
glass from which it had been evaporated. 
Sulphate of barytes, as might be supposed, proved much 
more difficult of decomposition than either sulphate of stron- 
tites or fluate of lime. I had made four or five experiments 
upon it, with the same kind of apparatus that had been 
applied to the fluate of lime, before I was able to gain de- 
cided results. In the last process performed on this sub- 
stance, two pieces of a large single crystal were hollowed by 
grinding, so as to contain about five grains of water each ; 
