Il2 REFUTATION OP THE SALT RADICAL THEORY, 
in the case of sulphate of soda, and chloride of sodium, 
while in other cases there is the greatest discordancy, (as 
in the stony silicate felspar, and the gaseous fluoride fluo- 
silicic acid gas; as in soap and Derhyshire spar; as in 
marble and the fuming liquor of Libavius, the sour proto- 
chloride of tin, and sweet acetate of lead,) is it reasonable to 
found an argument in favor of a hypothetical similitude in 
composition, on the resemblance of the two classes in pro- 
perties? Does not the extreme dissimilitude in some cases, 
more than countervail the limited resemblance in others? 
And when the great variety of properties displayed both by 
the amphide and haloid salts is considered, is it a cause for 
wonder or perplexity, that in some instances, amphide salts 
should be found to resemble those of the other kind? 
25. Again, admitting that there was any cause for per- 
plexity agreeably to the old doctrine, is there less, agreeably 
to that which is now recommended? Is there no ground 
for wonder that oxygen or sulphur cannot act as simple 
halogen bodies? By what rule are their binary compounds 
to be excluded from (he class of haloid salts? Wherefore 
should chlorides, bromides, iodides, and fluorides, however 
antisaline in their properties, be considered as salts, while 
in no case is an oxide, a sulphide, selenide or telluride to be 
deemed worthy of that name? 
26. I challenge any chemist to assign any good reason 
wherefore the red iodide of mercury is any more a salt than 
the red oxide, or the protochloride is more saline than the 
sulphide: or why the volatile oxides of osmium or of arsenic 
are less saline than horn silver or horn lead; or the volatile 
chloride of arsenic, than the comparatively fixed sulphides 
of the same metal: why gaseous chlorohydric acid is more 
saline than steam or gaseous oxhydric acid, as aqueous 
vapor may be designated without any inconsistency. 
27. It much surprises me, that when so much stress is 
laid upon the idea of a salt, the impossibility of defining the 
meaning of the word escapes attention. How is a salt to be 
