July 16, 1870.] 
THE PHARMACEUTICAL JOURNAL. 
45 
Under 
5 years’ 
service. 
Under 
8 years’ 
service. 
Under 
11 years’ 
service. 
Under 
14 years’ 
service. 
Under 
17 years’ 
service. 
Under 
20 years’ 
service. 
5s. 
5s. 6d. 
6 s. 
6s. 6d. 
7s. 6^. 
8s. 6d. 
and for every additional year an addition of Qd. per 
diem, till 10s. a day is reached. 
5. When in charge of stores an additional allowance 
will he granted, viz. at Haslar and Plymouth Hospitals 
2s. per day, with the title of Dispenser; and at other 
Home and all Foreign Hospitals Is. per day. 
6. An allowance of 6^. per day, in lieu of fuel and 
lights, will he granted to all Dispensers and Assistant- 
Dispensers, and they will he provided, with quarters. 
7. Superannuation will he allowed in accordance with 
the Superannuation Act of 1859, and a Certificate. of 
Qualification will he required from the Civil Service 
Commissioners, under the terms of the Order in Council 
of 4th June, 1870, published in the ‘London Gazette’ of 
the 7th June, 1870. 
8. Assistant-Dispensers will he liable to serve in any 
of her Majesty’s Naval Hospitals at home .or abroad, to 
which they may from time to time.be appointed. 
By command of their Lordships, 
Vernon Lushington. 
ON THE COMBINATIONS OF CARBONIC 
ANHYDRIDE WITH AMMONIA AND WATER. 
BY EDWARD DIVERS, M.D. 
The following paper contains an account of some, in¬ 
vestigations that I have made on the chemical reactions 
and combinations of carbonic anhydride, ammonia, and 
water with each other. The properties and relations of 
such bodies as these being of primary importance in. the 
theory of chemistry, they have indeed already received 
a large share of the attention of chemists; and there¬ 
fore, besides much that has come to be. known concern¬ 
ing them, of which it would be impossible now to ascer¬ 
tain the discoverers, several valuable memoirs have been 
written upon them. Nevertheless, I think it will be 
generally admitted that the combinations of these bodies 
are still felt not to conform in a clear manner to the 
ammonium theory, the theory of the general constitu¬ 
tion of salts, and even the theory of combining propor¬ 
tions. 
In attempting to arrive at a more satisfactory know¬ 
ledge of these combinations, I have made out much that 
I believe will be found to be new, both to chemical lite¬ 
rature and the traditions of the laboratory, and of ser¬ 
vice in helping to decide as to the normal character of 
these combinations. 
General History. —The first contribution to a know¬ 
ledge of the chemistry of the carbonated compounds of 
ammonia must be considered to be that of Black* * * § in 
1756, pointing out the difference between solution of 
ammonia and the solid carbonate of commerce. After 
this we find Priestley making out the difference between 
ammonia and its carbonate in his ‘ Experiments and 
Observations relating to Alkaline Air’ in I774.f 
The first recorded quantitative analysis of a compound 
of carbonic anhydride and ammonia, as far as I can dis¬ 
cover, is that by Bergmann, in 1774. J 
The variable composition of the compounds of car? 
* ‘Experiments on Magnesia, Quicklime, and other Alka¬ 
line Substances;’ Edinburgh (1777), pp. 65, 86, 103, and 
109. 
•j" ‘ Experiments and Observations on different Kinds of 
Air,’ vol. i. p. 163. 
J Works, translated by Cullen, vol. i. p. 29. Of the 
“ Aerial Acid,” paper read in 1774. 
bonic anhydride and ammonia was pointed out in 1 1 99 
by Sir Humphry Davy,* but the results he obtained prov¬ 
ing to be erroneous, his statements were untrustworthy. 
The fact of the existence of different carbonates was 
afterwards confirmed by Berthollet, Dalton, and others. 
The Ammonium Carbonates. —I. Normal Ammonium 
Carbonate. 
There are certainly three combinations of ammonia 
and carbonic anhydride, into the formation of which 
water enters in sufficient relative quantity to allow of 
their being represented as ammonium salts of carbonic 
acid,—the normal, the half-acid, and the acid carbonate. 
Since writing the note on the preparation and compo¬ 
sition of the first-named of these in the ‘ Philosophical 
Magazine,’ I have ascertained several interesting parti¬ 
culars in the chemical conduct of this substance, so that 
the facts there communicated form only a small part of 
the history of this salt I am now able to give. 
History. —The want of the normal carbonate of ammo¬ 
nium was only felt after Berzelius had promulgated his 
ammonium theory; until then the carbonate, C 0 2 (NH 3 ) 2 , 
had been considered to be this body. 
Berthollet,f in 1806, by distilling a solution of the 
acid carbonate, obtained a weak solution of normal car¬ 
bonate (“subcarbonate”) as the distillate. But Dalton 
was the first to describe a solid carbonate, neutral in 
composition, in 1813.* He ascertained that the carbo¬ 
nate of commerce did not contain two atoms of ammonia 
to one of carbonic anhydride, and prepared a hydrated 
compound of these bodies in this proportion..^ 
This compound contained, according to him, one atom 
of water, and would therefore be represented by the 
formula, 
C0 2 0H 2 (NH 3 ) 2 . 
The percentage number which he gives for the am¬ 
monia is indeed very incorrect in itself; but then.he de¬ 
termined it by using standard solution of sulphuric acid, 
and, as we all know, the equivalent number he adopted 
for ammonia is wide of the true one. But then he clearly 
established that in the acid carbonate the acid is only 
half saturated with ammonia, and. that in the normal 
carbonate discovered by him the acid is fully saturated. 
He was, however, also wrong in representing the nor¬ 
mal salt to contain, like the acid salt, but one atom of 
water to one atom of carbonic anhydride instead of two, 
as his analytical results really indicated. The following 
is his statement of the composition of the two salts 
* Works, vol. iii. p. 47. 
f £ Journal de Physique,’ vol. lxiv. p. 168. Troisieme suite 
des Recherch.es sur les Lois de l’Affinite. Extracted from 
the ‘ Memoires de l’lnstitut de France ’ for 1806. 
+ * Experiments and. Observations on tbe Combinations of 
Carbonic Acid and Ammonia.’ Mem. of the Lit. and Phil. 
Soc. of Manchester (2), vol. iii. p. 18; 1819. . 
§ So far as I can ascertain he has never received credit for 
this, or for the real excellence of his paper, in spite of the 
errors it contains. Indeed Henry, in his £ Life of Dalton ’ 
(Cavendish Society’s Publications), speaks very disparagingly 
of this paper. The circumstances that seem to me to have 
contributed to this result are:—(1.) The paper was published 
five years after it was read, in a journal which probably had 
a very limited Continental circulation. (2.) The calculations 
of the results of his analysis are erroneous, in consequence of 
the atomic weight—6—he adopted for ammonia. (3.) It 
contains some decided errors, among which, unfortunately, is 
that of denying the correctness of Gay-Lussac s researches on 
the proportion by volume in which ammonia combines with 
carbonic anhydride. (4.) It was severely criticized by Thom¬ 
son, in his ‘Annals of Philosophy’ (vol. xv. p. 137), who, 
nevertheless, besides erring himself in his correction oi -Dal¬ 
ton’s remarks on Gay-Lussac’s researches, also misstates 
another conclusion at which Dalton had arrived. 
