January 23, 1871.] 
THE PHARMACEUTICAL JOURNAL AND TRANSACTIONS. 
GOO 
mentary bodies, and also to that of the remarkable 
relations discovered by Kopp between the composition 
nnd boiling-points of many organic liquids. We have 
already seen an illustration of one of these disturbing 
influences in the fact that dilute nitric acid, when mixed 
with water, gives a slight fall of temperature, hydro¬ 
chloric acid a rise ; and the differences of specific heat in 
the solutions formed will, to a small extent, modify the 
results. But the cause of the higher thermal power of 
sulphuric acid I have not been able to discover, and 
future researches must decide whether it depends upon 
.some disturbing cause, or (which is less probable) upon 
its possessing an exceptionally high thermal power. 
One condition is, however, essential, or Law 1 will not 
apply. The acid and base must be capable of combining 
when brought into contact, and of forming a stable com¬ 
pound. In the paper so often referred to, I showed that 
hydrocyanic acid and potash, which fail to fulfil this 
condition, do not disengage the normal amount of heat 
when mixed; and the same observation will doubtless 
be found to apply to a large number of metallic oxides 
which form unstable compounds with, and imperfectly 
neutralizes the bases. 
As regards the experimental proofs of the other laws, 
even those of the fourth law, the truth of 'which is ad¬ 
mitted by MM. Favre and Silbermann, they are only 
approximative, and here also we meet occasionally with 
peculiar and imexpected results. Thus, a slight fall of 
temperature occurs, as Hess showed long ago, in the 
conversion of the neutral sulphate of potash into the 
acid salt; and I found, as, indeed, might have been ex¬ 
pected from their alkaline reaction, that in the conver¬ 
sion of the ordinary phosphates and arseniates into 
sup or salts a disengagement of heat occurs, amounting to 
about one-seventh of that disengaged in the formation of 
the salts themselves. In other cases results, at first 
view startling and apparently anomalous, will be found 
to be strictly in accordance with the general principles 
already laid down. In the formation of double salts 
there is no disengagement of heat, a principle announced 
in 1811, and which ought perhaps to be enunciated as a 
distinct law, although it is implicitly involved in Law 2. 
Again, if tribasic phosphoric acid or arsenic acid is 
added in fractional portions to a solution of potash till 
the subsalts are formed, the heat disengaged on each ad¬ 
dition of acid corresponds to the amount of acid added; 
but after this point has been reached the disengagement 
of heat follows a different law. Pyrophosphoric acid, on 
the other hand, behaves in the same way as nitric and 
most other acids when added in successive portions to 
solutions of potash or soda, equal increments of heat be¬ 
ing evolved for equal additions of acid till the pyrophos¬ 
phate of potash or soda is formed.* 
Appendix. 
In the following tables I have given the results, de¬ 
scribed in this communication and those of 1841 in a 
form which admits of comparison with one another, and 
with those of MM. Favre and Silbermann. I have also 
added a few determinations recently made by M. Thom¬ 
sen, of Copenhagen.f It will be seen that the. original 
experiments of 1841 exhibit, on the whole, a fair agree¬ 
ment with those now communicated to the Society. 
From the small scale on which they were performed (the 
whole weight of the solutions after mixture being less 
than 30 grammes), the imperfect form of the apparatus, 
and the uncertainty of the thermometric indications, I 
have indeed been surprised to find them so near the 
truth. The results of MM. Favre and Silbermann do 
not exhibit the precision which might have been ex- 
* ‘Transactions of the Royal Irish Academy,’ vol. xix. pp. 
245-248. The observations of Graham confirm the statement 
that no heat is evolved in the formation of any double salt. 
* Memoirs of the Chemical Society,’ vol. i. p. 83. 
t Poggendorff’s ‘Annalen,’ cxxxviii. p. 78. 
pcctcd from the high character of those experimentalists, 
and from the accuracy of other parts of their great work. 
The mercurial calorimeter employed by them appears to 
have been little adapted to its purpose; but after mak¬ 
ing due allowance for its imperfections, I am at a loss to 
account for the serious errors into which they have 
fallen. M. Thomsen’s experiments have evidently been 
made with care, and his results agree comparatively 
with my own; but the absolute amount of heat obtained 
by him falls far short of what I have foimd. It is, in¬ 
deed, much easier to obtain results relatively than abso¬ 
lutely correct. The numbers given in this paper will, I 
believe, be found rarely to differ relatively more than 
2 jjoth from the truth, but they may hereafter require a 
small correction in respect of their absolute value. That 
correction can, however, be scarcely more than J^th of the 
whole amount, and I have little doubt that the number, 
for example, given by Thomsen to express the heat dis¬ 
engaged in the combination of soda with nitric acid will 
prove to be as far below the true number as that given 
by MM. Favre and Silbermann is above it. 
Table I.— Potash. 
Acid. 
Andrews, 
1841. 
Favre and 
Silbermann. 
Andrews, 
1870. 
Sulphuric . . . 
Nitric .... 
Hydrochloric . . 
Oxalic .... 
Acetic .... 
Tartaric .... 
16,330 
15,076 
14,634 
14,771 
14,257 
13,612 
16,083 
15,510 
15,656 
14,156 
13,973 
13,425 
16,701 
14,800 
14,940 
15,124 
13,805 
13,508 
Table II.— Soda. 
Acid. 
Andrews, 
1841. 
Favre and 
Silbermann. 
Andrews, 
1870. 
Thomsen. 
Sulphuric. . 
Nitric . . . 
Hydrochloric 
Oxalic . . . 
Acetic . . . 
Tartaric . . 
16,483 
14,288 
14,926 
14,796 
14,046 
13,135 
15,810 
15,283 
15,128 
13,752 
13,600 
13,651 
16,580 
14,480 
14,744 
15,032 
14,000 
13,400 
15,689 
13,617 
13,740 
• • 
• • 
• • 
Table III. — Ammonia. 
Acid 1 Andrews, 
AC1CU 1841. 
Favre and 
Silbermann. 
Andrews, 
1870. 
Sulphuric . . . 
Nitric .... 
Hydrochloric . . 
Oxalic .... 
Acetic .... 
Tartaric .... 
14,135 
12,440 
12,440 
12,684 
12,195 
11,400 
14,690 
13,676 
13,536 
12,649 
•• 
14,710 
12,683 
12,964 
13,088 
12,316 
11,744 
Preserved Meat.— There has lately been a trial of 
preserved meat from Rosario, in the Argentine Republic, 
with, it is stated, satisfactory results. Preservation was 
effected by immersion in bisulphite of lime, according to 
the process of Messrs. Medlock and Bailey, of Wolver¬ 
hampton ; and the meat was sealed up in a cask, in the 
presence of the British Consul at Rosario, on August 10th 
last, and brought by him to England in a recent steamer. 
It had, therefore, been kept four months, and had made 
a passage across the Line .—Journal of the Society of Arts. 
Glycerine Inhalation in Cronp. Dr. Stehbergei, 
of Mannheim, reports that he has successfully used, inha¬ 
lation of glycerine, through Siegle’s apparatus, in the 
early stages of croup. The glycerine, if pure, is used un¬ 
mixed; if not pure, it is diluted with a little water. 
British Medical Journal. 
