Bibliography. 151 
up into HCl, and C4 Hs Cl, these being products of substitution from 
Cs Ha, and from Cle ; for these decompositions are always reciprocal, 
and C4 Hs is equivalent to Cl and to H. The author insists that the 
notion of equivalents has been too much restricted by the definitions 
imposed at an early period of the science, and with Gerhardt considers 
fifty-eight parts of manganese in permanganic acid, to be as truly the 
equivalent of Cl and of H, as twenty-eight parts are in the protosalts, 
or eighteen and two-thirds parts, in the persalts of that metal. Organ- 
ie is distinguished from inorganic chemistry, as being the chemistry of 
the carbon series, including all those bodies which evolve carbon in 
their ultimate chemical analysis. But even this distinction is arbitrary, 
and there are groups of homologous bodies which unite the two divis- 
tons. Hydrogen, in its equivalent of four volumes, and represented as 
Ha, is regarded as a type of all the hydrocarbons, and the homologue 
of such as are represented by (C2 Hz)nH2; while hydrochloric acid, 
HCl, the metals, M2, and the hydrid of copper of Wurtz, Cuz H, or 
Cu H, in which cuprosum, or copper in twice its ordinary equivalent, 
Teplaces H, are species of the same type. 
_ Water, represented as H2 Oz, and equal to four volumes of vapor, 
18 In the same way bibasic, being the prototype of oxyds, hydroxyds, 
and sulphids, and the functional homologue of the alcohols, and ethers 
of the formula, (C2 Hez)n, H2 O02. All the other ethers are homolo- 
§0us with their parent acids. These important relations, since recog- 
nized by Gerhardt and Laurent, were first pointed out by the author, in 
© pages of this Journal.* 3 
The Peroxyds like Ba2 Oa, and the corresponding sulphids, are not 
regarded as ies in which the metal unites in a less equivalent than 
in the protoxyds, but, from analogy with the higher sulphuretted ethers, 
48 Protoxyds and protosulphids, which have directly fixed O2 and S2, 
Without g 
Y 8 metal, thus explaining the loss of basicity, which the hy pothesis 
of Gerhardt leaves unaccounted for. This question has been treated 
at length by the author in this Journal.t E 
ee ribing the cyanic compounds, he suggests that oxygen may be 
* hy 
the C2 HN for the Oz He of any alcohol, enables us to add C2 to 
gro 
anic scale 
Bouis ; polycyanids, whose equivalent he finds in the liquid obtained by 
Is 1 y 
j < . . d 
. ‘M acting with chlorine, aided by sunlight, upon a hot saturate 
“lation of cyanid of mercuy, and having the formula C12 Na Clie, 
* March, 1848, p. 265, and July, 1849, p. 91, et seq. 
t May, 1849, p. 399, and July, 1849, p. 89. 
