BY DR. HARE. 
205 
only capable of liquifaction by water, the other by ca- 
loric. 
59. In support of his opinions the author adverts to the 
fact, that with hydrated sulphuric acid, baryta will combine 
energetically in the cold, while a similar union between the 
anhydrous vapor and the same base cannot be accomplished 
without heat. But it ought to be recollected, that to make 
this argument good, it should be shown wherefore heat 
causes baryta, a perfectly fixed body to unite more 
readily with an aeriform substance in which increase of 
temperature must, by rarefaction, diminish the number of 
its particles in contact with the solid. If the only answer 
be, that heat effects some mysterious changes in affinity, (or 
as I would say in the electrical state of the particles,) it 
should be shown that the presence of water, or any other 
base, has not been productive of a similar change, before 
another explanation is held to be necessary. But I would 
also call to mind that the hydrated acid is presented in the 
liquid state; and if it be asked why water, having less 
affinity than baryta, can better cause the condensation of 
the acid, I reply, that it is brought into contact with the 
acid both as a liquid and a vapor, of neither of which forms 
is the earthy base susceptible. But if all that is necessary 
to convert anhydrous sulphuric acid into an oxysulphionide, 
be an atom of oxygen and an atom of metal, what is to pre- 
vent baryta and anhydrous sulphuric acid from forming an 
oxysulphionide of barium? All the elements are present 
which are necessary to form either a sulphate or oxysul- 
phionide; and I am unable to conceive wherefore the ina- 
bility to combine does not operate as much against the 
existence of radicals as of bases. 
60. I would be glad to learn why. agreeably to the salt 
radical theory, anhydrous sulphuric acid unites with water 
more greedily than with baryta, and yet abandons the water 
promptly on being presented to this base. Why should it 
form an oxysulphionide with hydrogen more readily than 
