160 Mr. Faraday on the mutual action of sulphuric acid 
takes place, the results above, minus the baryta, will repre- 
sent its composition : from which it would appear, that one 
proportional of the acid consists of two proportionals of sul- 
phuric acid, twenty of carbon, and eight of hydrogen ; these 
constituents 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 combi- 
nation, is neutralized by the hydro-carbon ; or, to speak in 
more general terms, that the hydro-carbon has diminished 
the saturating 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 occurring 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 regard to muriatic acid, in the curious com- 
pound 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 experiments to the Royal Society, and as 
regards date they precede 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 hydrogen 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 pursue these refinements of the subject, or to 
