404 Mr. Faraday on the mutual Action of Sulphuric Acid 
the salt, in the determination of which most errors are in- 
volved. The quantity of oxide of copper and of acids re- 
quired to be used in that part of the analysis, may have intro- 
duced errors, affecting the small quantity of salt employed, 
which when multiplied, as in the deduction of the numbers 
above relative to 100 parts, may have created an error of that 
amount. 
As there is no reason to suppose that during the combina- 
tion of the acid with the baryta any change in its proportions 
takes place, the results above, minus the baryta, will represent 
its composition: from which it would appear, that one pro- 
portional of the acid consists of two proportionals of sulphuric 
acid, twenty of carbon, and eight of hydrogen ; these consti- 
tuents forming an acid equivalent in saturating power to one 
proportional of other acids. Hence it would seem, that half 
the sulphuric acid present, at least when in combination, is 
neutralized by the hydro-carbon; or, to speak in more ge- 
neral terms, that the hydro-carbon has diminished the satu- 
rating power of the sulphuric acid to one half. This very 
curious and interesting fact in chemical affinity was however 
made known to me by Mr. Hennell of Apothecaries’ Hall, as oc- 
curring in some other compounds of sulphuric acid and hydro- 
carbon, before I had completed the analysis of the present 
acid and salts; and a similar circumstance is known with re- 
ard to muriatic acid, in the curious compound discovered by 
M. Kind, which it forms with oil of turpentine. Mr. Hennell 
is I believe on the point of offering an account of his expe- 
riments to the Royal Society, and as regards date they pre- 
cede mine. 
It may be observed, that the existence of sulphuric acid in 
the new compounds, is assumed, rather than proved ; and that 
the non-appearance of sulphurous acid, when sulphuric acid 
and naphthaline act on each other, is not conclusive as to the 
non-reaction of the bodies. It is possible that part of the hy- 
drogen of the naphthaline may take oxygen from one of the 
proportions of the sulphuric acid, leaving the hypo-sulphuric 
acid of Welter and Gay-Lussac, which with the hydro-carbon 
may constitute the new acid. I have not time at present to 
ursue these refinements of the subject, or to repeat the ana- 
lyses which have been made of naphthaline, and which would 
throw light upon the question. Such a view would account 
for a part of the overplus in weight, but not for the excess of 
the sulphuric acid obtained, above two proportionals. 
The glowing salt of baryta was now analysed by a process 
similar to that adopted for the flaming salt. The specimen 
operated 
