TRANSFORMATION OF NITROAMINES AND ALLIED SUBSTANCES. 149 
In 65 per cent. acetic acid an equilibrium constant is obtained only when 
the reaction is represented as :— 
Ar.NCl.Ac+ H: + Cl’? Ar.NH.Ac+Cl, ; 
that is, the equilibrium constant is proportional to the second power of 
the concentration of the acid. 
In 50 per cent. acetic acid, at a concentration of 0-025 gram molecules 
per litre, the system is represented by the left-hand side of the equation, 
chlorine and anilide only appearing at higher concentrations. 
-3. Measurements of the velocity of the formation of the chlorinated 
anilide show :— 
(a) In glacial acetic acid the reaction is apparently dimolecular. If 
the concentration of the hydrochloric acid is small relative to 
the chloroamine the reaction becomes apparently monomolecu- 
lar, and its speed is proportional to the square of the concen- 
tration of the hydrochloric acid. 
(b) As the acetic acid is diluted to 95 per cent., the speed of the 
chlorination increases proportionately to the quantity of 
water added, 
As the proportion of water is further increased the velocity of 
the reaction falls, becoming scarcely perceptible in 30 per cent. 
acetic acid. 
(c) In aqueous acetic acid containing 70 to 90 per cent. acetic acid, 
there is no simple relation between the velocity of the change 
and the concentration of the hydrochloric acid. Below 65 
per cent, acetic acid the velocity is proportional to the square 
of the concentration of the catalyst. 
= 
Topographical and Geological Terms used locally in South 
Africa.—Report of the Committee, consisting of Mr. G. W. 
LampLueuH (Chairman), Dr. F. H. Hatcu (Secretary), Dr. G. 
CORSTORPHINE, and Messrs. A. pu Torr, A. P. Hawn, G. 
Kynaston, F. P. Menneuu, and A. W. Rocers, appointed 
to determine the precise Significance of Topographical and 
Geological Terms used locally in South Africa. (Drawn up 
by the Secretary.) 
Ow1na to the absence of the Secretary (Dr. F. H. Hatch) in South 
Africa, no further compilation could be got ready for publication this 
year. After consultation with other members of the Committee, how- 
ever, the Secretary proposes the following emendations in definitions or 
spelling of terms in the list published last year. The Committee ask 
for reappointment. 
Duin, plural duine 
A sand dune. 
Gouph (pronounced ‘ cope ’) 
A Bushman word, meaning ‘as dry as can be,’ applied to a portion of the 
Western Karroo. 
