262 . REPORT—1885. 
Third Report of the Committee, consisting of Professors WILLIAMSON, — 
DEWAR, FRANKLAND, CruM Brown, ODLING, and ARMSTRONG, — 
Drs. Hugo M@uuer, F. R. Japp, and H. Forster Moruey, and — 
Messrs. A. G. VERNON Harcourt, C. E. Groves, J. MILLAR ~ 
THomson, H. B. Dixon (Secretary), and V. H. VELEY, reap- 
pointed for the purpose of drawing wp a statement of the 
varieties of Chemical Names which have come into use, for 
indicating the causes which have led to their adoption, and — 
for considering what can be done to bring about some conver= — 
gence of the views on Chemical Nomenclature obtaining among 
English and foreign chemists. 
Aw account of the authorship of some of the various systems of nomen- 
clature which have been devised for the purpose of distinguishing between 
compounds formed by the union of the same elements in different propor- 
tions, has been given in the ‘ Historical Notes’ prefixed to the Second 
Report of this Committee. Among these systems the use of the termina- 
tions ous and ic, to denote respectively lower or higher degrees of saturation — 
of one element or group with another element or group, is perhaps that 
which has met with the widest acceptance. This system further directs 
that when electro-negative groups, the names of which end in ows and ic, 
unite with electro-positive groups to form salts, these terminations are to 
be changed into ite and ate respectively. 
Before proceeding to discuss the practical application of this system, 
it may be well to point out, as a minor etymological detail, that the literal 
meaning of the terminations ows and ic has altered since they were first — 
employed. Thus ous (Latin osus) ought to denote, on the part of the 
compound, richness in that element to the name of which the termination 
is attached. For example, cwprous (cuprosus) means ‘rich in copper’: 
cuprous oxide is primarily an oxide which is richer in copper than cupric 
oxide, and only by implication an oxide which is poorer in oxygen. This 
implied signification is, however, that in which the name cuprous owide 
is nowadays employed. A curious result of this change of literal meaning 
is to be found in the use of the prefix hypo to denote a still lower degree of 
saturation than that expressed by ous. Thus the name hyponitrous acid 
is taken to denote an acid containing still less oxygen than nitrous acid ; 
whereas hyponitrous really means ‘ less rich in nitrogen,’ which is the very 
opposite. Had the etymology been logically carried out, the prefix ought 
to have been hyper. A similar confusion of ideas is displayed in the use 
of the prefixes hyper and per at the other end of the scale; in place of 
these, hypo ought to have been employed. Perchromic acid does not, as 
its name literally taken signifies, contain more chromium than chromic 
acid: it contains less, and ought consequently to have been termed 
hypo-chromie acid. 
It need hardly be said that it would be ill-advised to attempt to 
change a system so firmly established as that involved in the present — 
use of these prefixes hypo and hyper; and in the above remarks on ~ 
the etymology of the subject, nothing of the kind is intended. No 
ambiguity can arise from the use of terms about the meaning of which 
everyone is agreed, and their mere etymological accuracy is, in view of 
this all-important consideration, of secondary importance. 
” aa. th 
