de chimie (see An. of Philosophy, vol. 14th, 1819) manifests great
ingenuity. It does not appear, however, so fortunate either in theory
or experiment as the former one. It would be difficult to convince any
one, either by reasoning or by experience that a number of particles
of mercury at the temperature of -40°, whether in the solid,, liquid,
or elastic state, have all the same capacity for heat. Indeed the
experiments of De la Roche and Berard, if they are to be credited,
demonstrate the inferior capacity of condensed air to rarefied air;
and if the same body changes its capacity in the elastic form, it may
well be concluded that all the three forms have not the same capacity.
M. M. Dulong and Petit have themselves shewn, in their former essay,
(see page 276) that solid bodies vary in their capacities for heat,
and that scarcely any two bodies, vary alike; hence it is impossible
that the product of the weight of the atom and specific heat of the
body should be a constant quantity. Their specific heat of certain
metals differ greatly from what is found by others. For instance, they
make the specific heat of lead .0293; the lowest authority I have
seen is Crawford, .0352, and the highest Kirwan .050; from repeated
trials I have lately found it, upon an average, .032. The weights of
some of the atoms in their table, differ materially from what are
commonly received; for instance, bismuth is 13.3 instead of 9; also
copper, silver, and cobalt, are only half the weights of some authors.
The gases too are unfortunate examples. Oxygen gas gives a product of
.236 instead of .375; azotic gas gives a product .1967, if oxygen be
to azote as 7 to 5, but a product of .393 if oxygen be to azote as 7
to 10: by Dr. Thomson’s ratio of oxygen to azote, 4 to 7, the product
will be .482, very different from .375. Hydrogen will give a product of
.47 or .41 instead of .375. All these differences, it may be said, are
occasioned by errors in the specific heats of the gases; but if errors
of this magnitude can still subsist after all the care that has been
taken, we shall scarcely know what to trust in experimental philosophy.
If M. Dulong would assume all his simple elements in an elastic state
and under one uniform pressure, the hypothesis would then make a
part of mine (vol. 1. page 70), and there is great reason to believe
it would be either accurately true or a good approximation; but to
suppose that some of the bodies should be in a solid state, having
their particles united by various degrees of attraction, others fluid,
and others in the elastic state, without any material modifications of
their heat arising from these circumstances, appears to me to be in
opposition to some of the best established phenomena in the mechanical
philosophy.
Their observations on the specific heat of compound elements, on
the relation of the heat developed by combination, as compared with
the heat of the elements before and after the combination, &c., are
not supported by a detail of actual experience. Heat given out by
chemical changes they suppose not to have been previously in a state of
combination with the elements. As an argument, the heat given out by
charcoal kept in a state of ignition, by a current of galvanic fluid,
is adduced. It is true this case is most easily explained, by allowing
that the galvanic fluid is in such circumstances converted into heat.
But the charcoal does not undergo any chemical change, and therefore
this is not a case in point.
All modern experience concurs in shewing that the heat of combustion
is primarily dependent on the quantity of oxygen combining. The heat
evolved by the combustion of phosphorus and hydrogen is very nearly,
if not accurately, in proportion to the oxygen spent. The heat by the
combustion of charcoal is not in a much less ratio: and I find the heat
in burning carbonic oxide, carburetted hydrogen and olefiant gas is the
same as in burning hydrogen gas, _provided the combining oxygen is the
same_.
One difficulty seems to have occurred to M. M. Dulong and Petit. They
all along conceive that the specific heats of bodies, that is, the
heats producing equal increments of temperature, must necessarily
be proportionate to their whole heat. This is purely hypothetical,
till established by experiment. The generality of writers on specific
heat had conceived it almost confirmed by experiment. The results of
Delaroche and Berard have shewn that in elastic fluids the increments
of heat are not proportional to the whole quantities, but on the
contrary are less when a body is elastic than when liquid. Indeed
some writers have argued this should be the case; because a body
nearly saturated with another has less affinity for it left.[27] It
is plain then that oxygen gas or any other elastic fluid, may have a
small specific heat in the sense above defined, and yet have an almost
unlimited quantity of heat. I am not aware of any one established
fact that does not admit of an explanation upon the hypothesis that
heat exists in definite quantities in all bodies, and is incapable of
any change, except perhaps into one of the other equally imponderable
bodies, light or electricity.
[Footnote 27: See Dr. Henry’s note, Manch. Memoirs, vol. 5, page 679.]
NEW TABLE OF THE
_Forces of Vapours in Contact with the
Generating Liquids at Different Temperatures._
(A) = Temperatures by the common thermometer.
(B) = Ether vapour, ratio 2 Spec. Gravity .72
(C) = Sulphuret of carbon vapour, ratio 1.978
(D) = Alcohol vapour, ratio 2.7 Spec. Gravity .82
(E) = Acetic acid vapour, ratio 2.57
(F) = Water, ratio 2.602()
-----+--------+--------+--------+--------+-------
(A) | (B) | (C) | (D) | (E) | (F)
-----+--------+--------+--------+--------+-------
| Inches | Inches | Inches | Inches |Inches
| of M. | of M. | of M. | of M. | of M.
-----+--------+--------+--------+--------+-------
7° | 3.75 | 3.134 | .193 | | .11
35 | 7.5 | 6.20 | .560 | .27 | .29
65+ | 15. | 12.26 | 1.51 | .69 | .75
97 | 30 | 24.26 | 4.07 | 1.77 | 1.95
133 | 60 | 48. | 11.00 | 4.54 | 5.07
173 | 120 | | 29.70 | 11.7 | 13.18
220 | 240 | | 80.2 | 30. | 34.2
272 | | | | | 88.9
340 | | | | | 231
-----+--------+--------+--------+--------+-------
This is an improved and extended table of the force
of vapour, similar to that at page 14, vol. I. It
shews that the different vapours increase inforce
in geometrical progression, to certain intervals
of temperature, the same to most or all liquids.
These intervals of temperature were presumed in the
former table, to be in reality _equal_ to one
another; but the accuracy of this last notion has been
questioned.
TABLE,
_Shewing the expansion of air, and the elastic
force of aqueous and ethereal vapour, at different
temperatures._
----------+---------+---------------+----------------+-------------
| | Utmost force of |
Temperat. | Vol. +---------------+----------------+Weight of 100
| of air. |Aqueous vapour.|Ethereal vapour.| cubic inches
----------+---------+---------------+----------------+ of aqueous
-28° | 420 | | | vapour.
-20 | 428 |Inches of Merc.|Inches of Merc. |
-10 | 438 +---------------+----------------+-------------
0 | 448 | .08 | | Grains.
10 | 458 | .12 | |
20 | 468 | .17 | |
30 | 478 | .24 | |
----------+---------+---------------+ |
32° | 480 | .26 | 7.00 | .178
33 | 481 | .27 | 7.18 | .184
34 | 482 | .28 | 7.36 | .191
35 | 483 | .29 | 7.54 | .197
36 | 484 | .30 | 7.73 | .203
37 | 485 | .31 | 7.92 | .209
38 | 486 | .32 | 8.11 | .216
39 | 487 | .33 | 8.30 | .222
40 | 488 | .34 | 8.50 | .229
41 | 489 | .35 | 8.70 | .235
42 | 490 | .37 | 8.90 | .245
43 | 491 | .38 | 9.10 | .255
44 | 492 | .40 | 9.31 | .267
45 | 493 | .41 | 9.52 | .275
46 | 494 | .43 | 9.74 | .284
47 | 495 | .44 | 9.96 | .293
48 | 496 | .46 | 10.18 | .303
49 | 497 | .47 | 10.41 | .313
50 | 498 | .49 | 10.64 | .323
51 | 499 | .50 | 10.87 | .329
52 | 500 | .52 | 11.10 | .341
53 | 501 | .54 | 11.34 | .354
54 | 502 | .56 | 11.59 | .366
55 | 503 | .58 | 11.85 | .378
56 | 504 | .59 | 12.12 | .384
57 | 505 | .61 | 12.39 | .396
58 | 506 | .62 | 12.66 | .402
59 | 507 | .64 | 12.94 | .414
60 | 508 | .65 | 13.22 | .420
61 | 509 | .67 | 13.51 | .432
62 | 510 | .69 | 13.80 | .444
63 | 511 | .71 | 14.10 | .456
64 | 512 | .73 | 14.41 | .468
65 | 513 | .75 | 14.72 | .480
66 | 514 | .77 | 15.04 | .492
67 | 515 | .80 | 15.36 | .509
68 | 516 | .82 | 15.68 | .521
69 | 517 | .85 | 15.90 | .539
70 | 518 | .87 | 16.23 | .551
71 | 519 | .90 | 16.56 | .569
72 | 520 | .92 | 17.00 | .580
73 | 521 | .95 | 17.35 | .598
74 | 522 | .97 | 17.71 | .610
75 | 523 | 1.00 | 18.08 | .627
76 | 524 | 1.03 | 18.45 | .645
77 | 525 | 1.06 | 18.83 | .662
78 | 526 | 1.09 | 19.21 | .680
79 | 527 | 1.12 | 19.60 | .700
80 | 528 | 1.16 | 20.00 | .721
----------+---------+---------------+----------------+-------------
_Applications of the above Table._
These tables will be found of great use in reducing volumes of air from
one temperature or pressure to any other given one: also in determining
the specific gravities of dry gases from experiments on those saturated
with or containing given quantities of aqueous or other vapours.
As several writers, and some of considerable eminence, have given
erroneous or imperfect formulæ on these subjects, more particularly
with regard to the effect of aqueous vapour in modifying the weights
and volumes of gases, it has been thought proper to subjoin the
following precepts and examples for the use of those who are not
sufficiently conversant in such calculations.
The 5th column of the above table, or weight of aqueous vapour, is
new, and may therefore require explanation. Gay Lussac is considered
the best authority in regard to the specific gravity of steam; but it
would be well if his results were confirmed or corrected, as they are
of importance. According to his experience, the specific gravities of
common air and of pure aqueous vapour, _of the same temperature and
pressure_, are as 8 to 5, or as 1 to .625. Now I assume that 100 cubic
inches of common air, free from moisture, of the temperature 60° and
the pressure of 30 inches of mercury, weigh 31 grains nearly. It is an
extraordinary fact that philosophers are not agreed upon the absolute
weight of a given volume of common air. Most authors now assume the
weight of 100 inches = 30.5 grains, whilst according to my experience
it is more than 31 grains. If common air be assumed 31 grains, steam
would be 19⅜ grains for 100 cubic inches, at the same temperature and
pressure, could it subsist; but as it cannot sustain that pressure
at the temperature of 60° we must deduct according to the diminished
pressure, the utmost force of steam at 60° being .65 parts of an inch
of mercury, we have 30 inches ∶ 19⅜ grains ∷ .65 ∶ .420 grains = the
weight of 100 cubic inches of aqueous vapour at 60° and pressure .65
parts of an inch; which is the number given above in the table. The
like calculation is required for any other pressure: but in addition
to this, there is to be an allowance for the temperature from the 2d
column: Thus, let the weight of 100 cubic inches of steam at 32° be
required. We have 30 inch. ∶ 19⅜ grs. ∷ .26 inch. ∶ .1679 grs.; the
weight of 100 inches of steam at 60°; then if 480 ∶ 508 ∷ .1679 ∶ .178
grs. = weight of 100 cubic inches of steam at 32° and pressure .26
parts of an inch, the tabular number required.
_Examples._
1. How many cubic inches of air at 60° are equivalent in weight to 100
cubic inches at 45°?
By the column headed _volume of air_ we have this proportion, if 493 ∶
508 ∷ 100 inch. ∶ 103.04 inches, the volume required.
2. How many cubic inches of air with the barometer at 30 inches height,
are equal in weight to 100 cubic inches when the barometer stands at
28.9 inches?
_Rule._ The volume of air being inversely as the pressure, we have, 30
∶ 28.9 ∷ 100 inches ∶ 96⅓ inches the answer.
3. How many cubic inches of dry air are there in 100 inches saturated
with aqueous vapour, at the temperature of 50°, and pressure 30 inches
of mercury?
Here the formula
(_p_ - _f_)
-----------
_p_
applies, where _p_ denotes the atmospheric pressure at the time, and
_f_ denotes the utmost force of vapour in contact with water at the
temperature. Hence _p_ = 30, _f_ = .49 per table, and we have
(_p_ - _f_) (30 - .49) 29.51
----------- = ----------- = ----- = 98¹¹/₃₀, or
_p_ 30 30
98¹¹/₃₀ percent dry air.
& 1¹⁹/₃₀ vapour.
---------
100.
If the vapour of ether is assumed, then _f_ = 10.64, and we have
(_p_ - _f_) (30 - 10.64) 19.36
----------- = ----------- = ----- =
_p_ 30 30
.645, ... or 64½ per cent dry air.[28]
35½ per cent ethereal vapour.
-----
100
[Footnote 28: The aqueous vapour in this case maybe considered as
insignificant.]
4. Suppose we find by trial the weight of 100 cubic inches of common
air saturated with vapour at 60°, the barometer standing at 30 inches
to be 30.5 grains, and the weight of hydrogen gas in like circumstances
to be 2.118 grains; query the weights of 100 cubic inches of each gas
free from vapour, and their specific gravities, the temperature and
pressure being as above?
If 30.5 ∶ 2.118 ∷ 1 ∶ .0694 = sp. gr. of vapourized hydrogen, that of
vapourized air being 1. Subtracting .42 grs. (weight of vapour per
table) from 30.5 grs., leaves 30.08 grains; and subtracting .65 parts
of an inch from 30 inches, leaves 29.35 inches. Hence 100 cubic inches
of dry air at the pressure of 29.35 inches, weigh 30.08 grains; and we
have 29.35 ∶ 30 ∷ 30.08 ∶ 30.746 grains, the weight of 100 inches of
dry air. Again, subtracting .42 grs. from 2.118, leaves 1.698 grains
= weight of 100 cubic inches of hydrogen of 60° and sustaining the
pressure of 29.35 inches; whence if 29.35 ∶ 30 ∷ 1.698 ∶ 1.736 grains,
weight of 100 inches of dry hydrogen; and 30.746 ∶ 1.736 ∷ 1 ∶ .05645
= sp. gr. of dry hydrogen, that of dry air being unity. Or the results
may be exhibited as under:
Weight of 100 cubic inches. Sp. Gravities.
Vap. air 30.5 grains 1 14.4
Vap. hydrogen 2.118 ---- .0694 1
Dry air 30.746 grains 1 17.7
Dry hydrogen 1.736 ---- .05645 1
FORMULÆ FOR DETERMINING THE PROPORTIONS OF COMBUSTIBLE GASES IN
MIXTURES.
It frequently happens, especially in the decomposition of vegetable
substances by heat, that the product consists of several combustible
gases in mixture, and it is desirable to determine the proportions of
each of those which collectively constitute the mixture. The following
forms will be found useful for this purpose.
1. _Carbonic oxide and hydrogen._
Let _x_ = the volume of carbonic oxide, _y_ = that of hydrogen, _w_ =
that of mixture, and _a_ = that of carbonic acid, produced by exploding
the mixed gases with oxygen over mercury.
Then the carbonic oxide, or _x_ = _a_,
and the hydrogen, or _y_ = _w_ - _a_.
2. _Sulphuretted hydrogen and hydrogen._
Let _x_ = the volume of sulphuretted hydrogen, _y_ = that of hydrogen,
_w_ = that of the mixture, and _g_ = the oxygen spent in the combustion
of _w_.
Then because _x_ + _y_ = _w_,
and 1½_x_ + ½_y_ = _g_;
we have _x_ = _g_ - ½_w_,
and _y_ = 1½_w_ - _g_.
3. _Phosphuretted hydrogen and hydrogen; also carburetted hydrogen and
hydrogen, and carburetted hydrogen and carbonic oxide._
The notation being as above, we have _x_ + _y_ = _w_, and 2_x_ + ½_y_ =
_g_ (see page 171): and,
2_g_ - _w_ 4_w_ - 2_g_
_x_ = -----------, and _y_ = -----------.
3 3
4. _Olefiant gas and carburetted hydrogen._
The notation being as above, we have
_x_ + _y_ = _w_, and
3_x_ + 2_y_ = _g_; whence
_x_ = _g_ - 2_w_ and
_y_ = 3_w_ - _g_.
5. _Carburetted hydrogen, carbonic oxide and hydrogen._
Let _x_ = carburetted hydrogen, _y_ = carbonic oxide, _z_ = the
hydrogen, _g_ = the oxygen spent in the combustion of _w_ volumes of
mixed gas, and _a_ = the carbonic acid produced.
Then _x_ + _y_ + _z_ = _w_,
_x_ + ½_y_ + ½_z_ = _g_,
and 2_x_ + _y_ = _a_.
whence we have
2_g_ - _w_ 3_a_ - 2_g_ + _w_
_x_ = -----------, _y_ = -----------------
3 3
and _z_ = _w_ - _a_.
6. _Olefiant gas, carburetted hydrogen and carbonic oxide._
Let _a_ = the olefiant gas, _y_ = the carburetted hydrogen, and _z_ =
equal the carbonic oxide, _g_ = the oxygen entering into combination,
and _a_ = the carbonic acid produced; also _w_ = the whole volume as
before.
Then we have _x_ + _y_ + _z_ = _w_,
3_x_ + 2_y_ + ½_z_ = _g_,
and 2_x_ + _y_ + _z_ = _a_.
Whence _x_ = _a_ - _w_,
_y_ = 4_w_ - 5_a_ + 2_g_
-------------------,
3
and _z_ = ⅔(_w_ + _a_ - _g_).
7. _Superolefiant gas,[29] carburetted hydrogen, and carbonic oxide._
[Footnote 29: A gas found in oil and coal gas. See Manchester Memoirs,
vol. 4 (new series), page 73.]
Let _x_ = volume of superolefiant, _y_ = volume of carburetted
hydrogen, _z_ = volume of carbonic oxide, _g_ = the oxygen combining,
_a_ = carbonic acid produced, and _w_ = volume of mixed gas.
Then _x_ + _y_ + _z_ = _w_,
4½_x_ + 2_y_ + ½_z_ = _g_,
and 3_x_ + _y_ + _z_ = _a_.
Whence _x_ = _a_ - _w_
----------,
2
_y_ = 3_w_ - 4_a_ + 2_g_
------------------,
3
and _z_ = 3_w_ - 4_g_ + 5_a_
-------------------.
6
8. _Superolefiant gas, carburetted hydrogen, carbonic oxide, and
hydrogen._
This is the mixture of gases obtained by a red heat from coal and oil,
after being freed from carbonic acid, &c., by the usual means.
This mixture requires a very complicated formula, in consequence of
the specific gravities of the gases entering into the calculus. The
importance of the subject however may be an apology for the labour.
Let _x_ = vol. of superolefiant, _S_ its sp. gr.
_y_ = vol. of carb. hydrogen, ∫ its sp. gr.
_z_ = vol. of carbonic oxide, _c_ its sp. gr.
& _u_ = vol. of hydrogen, _s_ its sp. gr.
_C_ = specific gravity of the mixture, _g_ = oxygen, _a_ = carbonic
acid, and _w_ = whole volume of mixture as before.
Then we have _x_ + _y_ + _z_ + _u_ = _w_
4½_x_ + 2_y_ + ½_z_ + ½_u_ = _g_
3_x_ + _y_ + _z_ = _a_
and _Sx_ + ∫_y_ + _cz_ + _su_ = _Cw_.
Whence _u_ =
(3_S_ + 5_c_ - 8∫)_a_ - (4_c_ - 4∫)_g_ - (3_S_ + 6_C_ - 6∫ - 3_c_)_w_
--------------------------------------------------------------------
8∫ + _c_ - 3_S_ - 6_s_.
The value of the hydrogen being obtained, it may be subtracted from
_w_, and the remainder will be best divided into three portions, by the
preceding formula.
HEAT PRODUCED BY THE COMBUSTION OF GASES.
Subsequent experience to that detailed at page 77, Vol. 1. has
furnished the following more correct results of the heat produced by
the combustion of pure gases.
Hydrogen, combustion of it raises an equal volume
of water 5°
Carbonic Oxide 4½
Carburetted Hydrogen, or Pond Gas 18
Olefiant Gas 27
Coal Gas (varies with the gas from 10° to) 16
Oil Gas (varies also with the gas from 12° to) 20
Generally the combustible gases give out heat nearly in proportion to
the oxygen they consume. See note at the end of Vol. 4, new series of
the Manchester memoirs.
ABSORPTION OF GASES BY WATER, &c.
This curious subject has attracted much less attention than it
deserves. Very little has been published relating to it since the time
of Dr. Henry’s essays and my own, now more than twenty years ago.
The only author I remember is M. Saussure of Geneva, who published a
similar essay about twelve years afterwards. See Thomson’s Annals of
Philosophy, Vol. 6. He investigates the quantities of gases absorbed
by various solid bodies, in a manner which I do not fully comprehend;
he then treats of the absorption of gases by liquids, adverting at
the same time to Dr. Henry’s experiments and mine. My enquiries were
principally confined to _one_ liquid, water; but I made a few trials
with others, such as weak aqueous solutions of salts, alcohol, &c.,
and observing no remarkable differences, I concluded somewhat too
hastily that “most liquids free from viscidity, such as acids, alcohol,
&c., absorb the same quantity of gases as pure water.” Manchester
memoirs, new series, Vol. 1. M. Saussure however asserts that there
are considerable differences in liquids in this respect. He finds
sulphuretted hydrogen to be more absorbable by water than Dr. Henry
and I did; in this I find he is right. Water takes about 2½ its bulk
of this gas when pure; and it seldom had been obtained unmixed with
hydrogen when Dr. Henry and I made our experiments upon its absorption.
In regard to carbonic acid, nitrous oxide, and olefiant gas, M.
Saussure nearly agrees with us; but his results with oxygen gas,
carbonic oxide, carburetted hydrogen, hydrogen and azote, would prove
that water absorbs twice the quantities of each that we have assigned.
I have no doubt he is wrong in the less absorbable gases. In the case
of absorption of mixed gases, Saussure has given four examples, in
which he finds the results to militate against my theoretic view, as
stated at page 201, Vol. 1.; namely, that water takes the same quantity
of each in a mixed state as it would do if they were separate, and in
other respects in like circumstances. But I have shewn in the Annals of
Philos. Vol. 7, 1816, that his results coincide as near as any one can
expect with the views which I have all along taken of this subject.
It will be seen, page 173, that another gas has been found to coincide
with olefiant gas in absorbability; namely, phosphuretted hydrogen.
FLUORIC ACID.--DEUTOXIDE OF HYDROGEN.
In treating of Fluoric acid, (Vol. 1, page 277) we came to the
conclusion that this acid was probably constituted of two atoms of
oxygen, and one of hydrogen, and have figured it accordingly (Plate 5,
fig. 38). Subsequent experience however has shewn that deutoxide of
hydrogen, though it can be formed synthetically, is not the same thing
as fluoric acid. We are indebted to M. Thenard for the discovery of
this curious compound, the deutoxide of hydrogen or oxygenated water.
An ingenious memoir on the subject was published by him in 1818, in
which the formation and the properties of this compound are fully
detailed. I had no small satisfaction in 1822, when at Paris, in being
obligingly favoured by M. Thenard with a view of the process of the
formation, and of the more distinguishing properties of this singular
liquid.
The nature of fluoric acid is still enveloped in obscurity. My
experience led me to adopt the composition of fluate of lime to be 40
acid and 60 lime per cent. I had not then seen Scheele’s admirable
essay on the subject. From the 5th section of his 2d. essay on fluor
mineral, 1771, it may be deduced that fluate of lime is composed of
72.5 lime and 27.5 acid per cent. In 1809 Klaproth, and near the same
time, Dr. Thomson found about 67½ lime and 32½ acid per cent. in
fluor spar. They both erred, no doubt, as I did, by not repeating the
treatment of the mineral with sulphuric acid often enough. Since then
most authors, as Davy, Berzelius, Thomson, &c., agree with Scheele
nearly, in assigning 27.5 acid, and 72.5 lime, in 100 parts of fluate
of lime. My experience in 1820 gave me 1 per cent. less of lime; and
Dr. Thomson now finds about 1 per cent. more of lime than Scheele’s
analysis gives.
If we estimate the atom of lime at 24, that of fluoric acid must be
about 9, according with the above proportion; this is much below 15,
the weight of an atom of deutoxide of hydrogen.
Should Sir H. Davy’s view of fluate of lime be found correct, its
atomic constitution would be one atom of _calcium_, the metallic
substance of which lime is the protoxide, and one atom of _fluorine_,
the name he has assigned to the other element, which with hydrogen is
supposed to constitute the fluoric acid. The atom of fluor spar would
then be 1 atom of calcium, 17, united to one atom of fluorine 16.
MURIATIC ACID.--OXYMURIATIC ACID, &c.
From the articles _muriatic acid_ and _oxymuriatic acid_ in the former
volume, published now 16 years ago, as well as from the appendix
to said volume, in which sundry animadversions are found on the
fluctuating opinions entertained in regard to these acids, the reader
will not be surprised to find some further addition.
Three notions have been submitted to the public in the last twenty
years in regard to the nature of muriatic acid. First, the gas detached
from common salt by sulphuric acid has been thought to be the acid in
a state of purity, and constituted of a certain base or radical united
to oxygen; this was the notion inculcated in the articles alluded to
above. Second,--it is stated as a fact that when oxymuriatic acid and
hydrogen in equal volumes are united by the electric spark, a volume
of muriatic acid gas is the result equal to the sum of both the other
volumes, and that this gas perfectly agrees with the gas obtained from
common salt by sulphuric acid; this suggested the idea that muriatic
acid gas is a compound of what has been called _real_ or _dry_ muriatic
acid one atom, and water one atom. And, third, it is argued, that
the element we have called oxymuriatic acid gas, is, for aught that
appears, a _simple_ body, and consequently, that muriatic acid gas is
the _real acid_, and is constituted as above, of one atom of hydrogen,
and one atom of oxymuriatic acid (now called _chlorine_.) It is not
intended here to enter into a discussion of the arguments and facts
adduced in support of the different conclusions. More experience
must be had before all the doubts and difficulties are removed from
the subject. But it will be proper to illustrate these different
positions by an example. For instance, common salt, muriate of soda or
chloride of sodium. By the first notion 50 parts of dry common salt
will consist of one atom of muriatic acid gas, 22, and one atom of
caustic soda, 28. By the second notion the same salt will be formed of
30 parts of muriatic acid gas, and 28 of caustic soda; but 8 parts of
water evaporate when the salt is dried. By the third view common salt
consists of oxymuriatic acid, or chlorine and sodium, or the metal of
which caustic soda is the protoxide; and 50 parts of salt will consist
of 29 chlorine and 21 sodium, or one atom of each.
NITRIC ACID--COMPOUNDS OF AZOTE AND OXYGEN.
Since the account of nitric acid (Vol. 1, page 343) was printed, a
change has universally taken place in estimating the weight of the
nitric acid atom, and of the proportion of azote and oxygen in the
same. This has been effected chiefly by a more correct analysis of
nitre than existed at that time. Nitre is now found to consist nearly
of 52 parts acid and 48 parts potash per cent. Hence if the atom of
potash be 42, that of nitric acid must be 45; for, 48 ∶ 52 ∷ 42 ∶ 45,
nearly. That is, the nitric acid atom consists of 10 azote + 35 oxygen
by weight; or of 2 atoms of azote (according to my estimate) and 5 of
oxygen. There appear to be _two_ nitrous acids; namely, the one which I
have designated by that name, which may now be called _subnitrous_, or
as Gay Lussac terms it _pernitrous_; and the other what I considered as
_nitric acid_ in the former volume, composed of 1 atom azote, and 2 of
oxygen.
Real nitric acid then is that combination which is effected by uniting
oxygen with a minimum of nitrous gas; or 1 measure of oxygen with
1.3 nitrous gas, (See Vol. 1, page 328). The oxynitric acid, which I
was led to infer from the last mentioned combination, (1 azote with
3 oxygen) does not appear to exist. The Table of nitric acid (Vol.
1, page 355) will require some correction. An increase of about 4
per cent. should be made, I apprehend, on the quantities of acid
corresponding to the several specific gravities.
Since my former volume of Chemistry was printed, several essays on
the compounds of azote and oxygen have been published, with some new
and some additional experiments, the chief of which may be seen in
Sir H. Davy’s Elements of Chemical Philosophy, the Annales de chimie
et de physique, Vol. 1; Annals of philosophy, Vol. 9 and 10; and
the Manchester Society’s Memoirs, Vol. 4, _second series_; also Dr.
Thomson’s first principles of Chemistry. Notwithstanding all that has
been written on the subject, there still appears uncertainty as to the
number of combinations formed by these two elements, their relative
weights, and the number of atoms in the several compounds.
The results of an experiment I lately made on the decomposition
of nitrate of potash by heat seem to be worthy of record, as I am
not acquainted with those of any other person who has pursued the
experiment to the same extent.--I took an iron retort of 6 cubic inches
capacity, and cleaned it as well as I could from carbonaceous matter
which it had previously contained, first by heating nitre to redness
for an hour or more in it, and then washing it repeatedly with water
till the liquid came out tasteless, and only mixed with a little red
rust; I then put in 480 grains of purified nitre, and having secured
a copper tube to the retort so as to be air tight, the retort was put
into a fire and gradually raised to a red heat, and the fire was
occasionally urged with a pair of bellows, in order to keep up a
glowing red on the retort for nearly two hours; the air was received
over water in jars; the first 4 or 5 inches were thrown away, and the
rest was preserved and transferred to a graduated jar; the products
were examined in successive portions as under, namely,
Inches.
1 produce, 85 cubic inches, 83 per cent. pure = 70.5
2 5 77 = 3.85
3 25 50 = 12.5
4 6 30 = 1.8
----- -------
Total 121 Oxygen 88.65
Oxygen 88.65 = 30 grains.
------
Residue 32.35 = 10 grains.
About 1 per cent. on the whole gas was carbonic acid, the rest oxygen
and azote, the weights of which would be nearly as above.
Towards the last the gas came very slowly, and being of inferior
quality, the operation was discontinued.
The remaining contents of the retort were diluted with water, and
well washed till the water ceased to shew alkali; the liquid was then
concentrated and gave 1600 water grain measures of the sp. gr. 1.153.
There were obtained also 64 grains of red oxide of iron from the
washing of the retort, containing 19 grains of oxygen.
The liquid was divided into portions and examined; the original nitre
consisted of 250 grains of nitric acid united to 230 of potash = 480
grains. After the process there appeared to be,
10 grains of carbonic acid united to 21 grains potash.
62 grains of subnitrous acid to 84 ” ”
134 grains nitric acid to 125 ” ”
---
230
The quantity of carbonic acid was determined by lime water: the
quantity of potash uncombined with nitric acid was found by
precipitating it by tartaric acid, and manifested 105 grains of potash
in the bitartrate = that combined with the carbonic and subnitrous
acids; from which subtracting 21, it was inferred the remainder 84 must
have been in union with subnitrous acid, or else with nitrous acid;
the rest of the potash, not being acted upon by tartaric acid, was
understood to be combined with nitric acid.
The quantity of subnitrous acid given above, appeared somewhat
hypothetical, till it was confirmed by treating a portion of the liquid
with oxymuriate of lime solution of known strength; it was found that
32 grains of oxygen were required to be combined with the subnitrous
acid, in order to restore it to the state of nitric acid; that is,
when oxymuriate of lime, containing that quantity of oxygen, was
added to the liquid, and this was afterwards rendered acidulous by the
addition of sulphuric acid, neither nitrous vapour nor oxymuriatic gas
was perceptible; but a greater or less quantity of the oxymuriate being
applied, and the liquid made acidulous, the fumes of the one or the
other were abundantly manifest.
It remains to account for the oxygen. There were 250 grains of nitric
acid at first in the nitre; of which 200 grains were oxygen and 50
azote, nearly. One-fifth part of the oxygen = 40 grains, corresponds
to 1 atom of oxygen. Now the whole of the oxygen derived from the
nitre in the course of the experiment, seems to be 30 grains in gas, 7
grains in the carbonic acid, and 19 grains in the iron oxide, together
equal to 56 grains. Now the azote and oxygen in the gas collected, were
very nearly in the proportion of those elements in nitric acid; so
that a portion of the acid (about ⅙) might be considered as completely
decomposed, whilst the rest was only losing a small part of its
oxygen: this is remarkable, and I think indicates that the carbonic
acid (formed from the carbon of the retort, or from the adhering
carbon) unites to the potash, expelling the _nitrous_ acid, which
is immediately decomposed into its elements azote and oxygen. This
would not however account for the whole of the azote: for, 40 grains
of nitric acid would be united to 37 potash; whereas we find only 21
potash with carbonic acid; and I cannot believe that an error in the
estimate of carbonate of potash could exist to that amount. The fact,
however, was, that the elements of 40 grains of nitric acid were found
in the evolved gas, and hence we have to account for the remainder 210
grains. From this there appears to have been expelled 26 grains of
oxygen, nearly 19 and 7 as related above; of which the 19 grains cannot
be correctly estimated by reason of the uncertainty as to the real
quantity of oxide formed during the operation: there might be some left
adhering to the retort, or on the other hand there might be more than
the due share, derived from former experiments. Supposing then, that
26 grains of oxygen were extracted from the nitric acid, the remaining
acid would require the same to be added to re-form the nitric; but
by the experiments with oxymuriate of lime it seemed to require 32
grains of oxygen. This difference wants an explanation; I believe the
greater error must belong to the 26 grains; perhaps the truth might be
approximated best by supposing both to be 30 grains.
When the liquid decomposed nitre is treated with any acid, a gas is
instantly expelled which produces red fumes in the air; it is pure
nitrous gas, which joining with the oxygen of the atmosphere, generates
nitrous acid vapour. At the same time, no doubt, the subnitrous acid is
disengaged from the potash, but that part of it which is real nitrous
acid (1 atom azote to 2 of oxygen) is retained by the water, whilst the
other part, (1 atom azote and 1 of oxygen) assumes the gaseous form. In
order to be satisfied respecting this point, I made several experiments
with the liquid over mercury: taking a given portion of the liquid,
and sending it to the top of a graduated tube filled with mercury, I
passed up as much muriatic acid as was sufficient to engage the potash;
immediately there was a disengagement of nitrous gas and carbonic
acid gas, and afterwards a slow evolution of gas, evidently arising
from the liquid in contact with the mercury. Wishing to ascertain the
quantities, I sent up 25 grain measures of liquid, and to that nearly
half its bulk of muriatic acid; in 2 or 3 minutes there was,
1.1 cubic inch of gas. H. M.
1.4 in 0 45
1.5 1 5
1.7 2 45
1.75 7 45
1.78 9 45
The gas was washed in lime water, and lost .33 parts of an inch of
carbonic acid; the rest, 1.45 cubic inch, was nitrous gas. It is
obvious that ½ of the nitrous gas, together with the carbonic acid, was
liberated instantly; the rest of the nitrous gas was due to the nitrous
acid, slowly acting upon the mercury. At the end of the process, there
was a little black oxide floating upon the mercury. Calculating from
this, the whole quantity of nitrous gas would be 31 or 32 grains,
whereas it ought to have been 48 grains to constitute 62 of subnitrous
acid. It is probable that whilst a portion of the subnitrous acid is
oxidizing the mercury, another portion may be forming nitric acid and
dissolving the oxide.
From some trials, I have reason to think that even carbonic acid will
expel nitrous gas from the liquid sub-nitrite of potash.
In the essay of Dr. Henry, already alluded to, published in the 4th
Vol. of the Manchester Society’s Memoirs, a new and interesting
discovery is made; namely, that a mixture of nitrous and olefiant
gases, though not explosive by an electric spark, may still be exploded
by the more powerful impetus of a shock from a charged jar. Dr. Henry
has adduced the results obtained in this way, as corroboratory of those
which shew the constitution of nitrous gas to be 1 volume of azote and
1 of oxygen united to form 2 volumes of nitrous gas. (See page 507 of
the Memoirs.)
Some time ago in repeating these experiments of Dr. Henry, I found
some extraordinary circumstances attending them. After determining
that 1 volume of olefiant gas may be fired with from 6 to 10 volumes
of nitrous, I found a shock from a jar sometimes inadequate to fire
the mixture, which, however, when repeated a second or third time,
succeeded. This is not a novelty; for, mixtures of olefiant gas as
well as other gases and vapours, with a minimum of oxygen, frequently
require several sparks before the explosion: but this case occurs at
times with nitrous and olefiant gas, when they are mixed in the most
favourable proportions for exploding. The most remarkable circumstance,
however, was, that when a phial was filled with the mixture of the
two gases in the proportion of 1 volume olefiant to 6 or 7 nitrous,
(exclusive of small portions of azote), the decomposition of the
nitrous gas and the combustion of the olefiant were scarcely ever
perfect; and what increased the perplexity more, was, the results
obtained from the same mixture scarcely ever agreed one with the
other. After about 30 experiments, I was inclined to adopt the
conclusion, that the uncertainty was occasioned by the oblong form of
the eudiometer. The spark or shock, in my eudiometer, is imparted at
one extremity of a column of air, which is often 10 times as much in
length as in diameter: it mostly was found that the larger the quantity
of mixture exploded at once, the more imperfect and incomplete was the
combustion. I imagine the intensity of heat is not sufficient to carry
on the combustion through the length of the column, owing, perhaps, to
the cooling power of the sides of the tube. Hence it was, I apprehend,
that in one or two instances, when a small quantity of gas was used,
I got nearly complete results, as Dr. Henry reports his; but in the
majority both gases were found in the residue after the explosion.
In pursuing this enquiry into the decomposition of nitrous gas
by combustible gases, I found that it might be effected by any
combustible gas or vapour: at least it succeeded in all I tried. The
method I pursued, and which was suggested by the known properties of
phosphuretted hydrogen, is this: it has been shewn (page 181) that
a mixture of phosphuretted hydrogen and nitrous gas exploded by an
electric spark, the former gas being completely burned in case the
proportions are duly adjusted; now, it occurred to me, that as the
above combustible gas is usually a mixture of pure phosphuretted
hydrogen and of hydrogen, and that the latter of these is also
burned as well as the former, the effect must be produced through
the heat occasioned by the combustion of the former. Having some old
phosphuretted hydrogen by me, at the time, which on examination, I
found to be 91 per cent. combustible gas, and 9 azote; and the 91
combined with 156 of oxygen, consequently was 74 pure, and 17 hydrogen;
I tried this mixture with nitrous gas, when it exploded by the spark,
as usual; but on trying it with an excess or defect of nitrous gas, the
spark was inefficient, but the shock instantly fired the mixture. As
there did not appear to be any of the pure hydrogen left unburned in
these experiments, I proceeded to mix the old phosphuretted hydrogen
with hydrogen; and then this new mixture with nitrous gas. The first
experiment was made with 4 parts of old phosphuretted hydrogen + 16
hydrogen + 36 nitrous gas = 56 total. On this mixture the spark, of
course, had no effect; but it exploded the first trial by the jar, and
left 20 measures, of which 2 were found to be oxygen, and the rest
azote. This experiment succeeding so well, I next tried mixtures of
phosphuretted hydrogen, with carbonic oxide, carburetted hydrogen, and
ether vapour successively, along with nitrous gas; and found that all
these mixtures refused combustion by the spark, but were instantly
exploded by the shock, yielding carbonic acid and water, the same as if
the combustion had been effected by free oxygen. In some instances the
combustion was complete, leaving neither combustible gas nor nitrous
gas; but generally there was a residue of one or both of the gases.
From these experiments it may be concluded that the heat, produced by
the combustion of phosphuretted hydrogen and nitrous gas or oxygen
gas, disposes other gases, accidentally in the mixture, to chemical
changes. In conformity with this view, I mixed phosphuretted hydrogen
and oxygen, in the proportion of mutual saturation; and taking a
small proportion of this mixture, and as much ammoniacal gas as would
saturate the phosphoric acid to be formed, I found that causing an
explosion over mercury, the phosphoric acid combined with the ammonia,
and nearly the whole gas disappeared. In this case, the heat was not
sufficient to decompose the ammonia. But in another experiment, with a
portion of the same explosive mixture and a less proportion of ammonia,
after the firing a residue of azote and hydrogen was found, amounting
nearly to the quantity due from the decomposition of the ammonia. Here
the heat produced, had evidently decomposed the ammonia.
ON AMMONIA.
The constitution of ammonia still remains undecided. The latest
experiments on this article are those of Dr. Henry, in his essay on
the analysis of the compounds of nitrogen. (Memoirs of the Manchester
Society, vol. 4, 1824.) By electrifying ammoniacal gas over mercury, as
carefully as could be devised, Dr. Henry found results as under:
1st experiment 44 measures became 88+
2d 157 320
3d 60 122
4th 120 240
The evolved gases carefully analysed by combustion with oxygen, were
found to consist of 3 volumes of hydrogen and 1 of azote. The analysis
of ammonia was also effected by exploding it with nitrous oxide, with
the requisite precautions. The results confirmed the previous ones
by electricity, both in regard to doubling the volume of ammonia,
and establishing the ratio of 3 to 1 in the volume of hydrogen and
azote.--These experiments are highly interesting as far as regards the
question of ammonia, as they exhibit the latest investigations of one
who has previously shewn uncommon skill and perseverance in this kind
of analysis. (See Philos. Transact. 1809, &c.)
Dr. Henry’s analysis of ammonia, in 1809, has been adverted to in our
article on the subject, vol. 1, page 429. The results of that Essay are
given in a tabular form; and the mean of six experiments was nearly
as we have stated, namely, that ammonia consists of 27¼ measures of
azote, and 72¾ hydrogen. To this it may be proper to add, that the two
extremes were, 26.1 azote and 73.9 hydrogen, and 28.2 azote with 71.8
hydrogen; also that a small error has crept into the table, which being
corrected, the average results are reduced to 27 and 73, very nearly.
Subsequently, both Dr. Henry and Sir H. Davy concurred in assigning 26
and 74 for the most approximating numbers. (See Nicholson’s Journal,
25, page 153). The true quantity of gases procured by the decomposition
of ammoniacal gas by electricity, was concluded by both these
authorities, to be 180 for each 100 of ammonia, when the requisite
precautions were taken, as we have related in vol. 1.
From what is stated above, it is evident the subject is one which
requires extraordinary skill and attention. This I can attest from my
own experience, which has been frequently renewed and varied; but the
results have not been sufficiently accordant to yield me satisfaction.
About ten years ago, I made several experiments on the decomposition
of ammonia, which, though they are not convincing, deserve, perhaps,
to be recorded in their results.--Some more recent experiments are
incorporated with them.
_Decomposition of ammonia by nitrous oxide._--I made many experiments,
by exploding mixtures of nitrous oxide and ammoniacal gases over
mercury. The excess of gas was mostly on the side of ammonia, but the
proportions were varied in the different experiments, from 10 vol.
nitrous oxide to 11 ammonia or to 5, which are about the extremes
capable of being fired by the electric spark.
When 10 parts nitrous oxide and 5 of ammonia are exploded over mercury,
the residuary gas contains some free oxygen and some nitrous acid
derived from the decomposition of the excess of nitrous oxide used;
with 6 parts of ammonia there is rarely any free oxygen. When 10 parts
of nitrous oxide, and 7 of ammonia are fired, I never found any free
oxygen or hydrogen; but when the ammonia is at or near 8 parts, I
find from ¹/₂₀ to ⅒ of the hydrogen from the ammonia in the residuary
gases. The two gases appear to be completely decomposed; the oxygen of
the nitrous oxide, as far as it can, unites with the hydrogen of the
ammonia, without forming any portion of nitrous acid or of free oxygen,
and the residue contains the azote of both gases, and the unburnt
hydrogen from the ammonia, as Dr. Henry first observed. This continues
to be the case till the ammonia becomes 11 parts, when the hydrogen
amounts to about ⅓ of the whole quantity which the ammonia yields.
From the above it would seem that the proportions for mutual saturation
must be 10 nitrous oxide with from 7 to 8 parts of ammonia. This
agrees with the deduction in Dr. Henry’s first essay that 13 nitrous
oxide require 10 of ammonia; or that 10 require 7.7: but according to
the theory of volumes 10 would require 6⅔; and Dr. Henry recommends
in his late essay 10 nitrous oxide to 7.7 or 8⅓ parts of ammonia, in
order to secure a small excess of the last, and consequently some
free hydrogen after the explosion. The former of these proportions
would have nearly ⅐ of the residue hydrogen, and the latter nearly ⅕,
supposing the gases pure originally. This gives more hydrogen than I
have ever found; but the azote in my experience nearly agrees with the
doctrine of multiple volumes.
_Decomposition of ammonia by nitrous gas._--About 30 experiments
carefully made on mixtures of nitrous gas and ammoniacal gas gave very
discordant results. At one time 10 parts nitrous gas with 14 ammonia
gave ⅓ of hydrogen in excess, and another time 10 nitrous with 12
ammonia gave excess of hydrogen = ⁹/₂₀; generally 10 parts with 6 or
less gave oxygen, and 10 with 8 or more gave hydrogen in the residue.
_Decomposition of ammonia by oxygen._--The limiting proportions of
oxygen and ammonia which I have fired, are 10 oxygen to 4 ammonia
for the minimum, and 10 oxygen to 22 ammonia for the maximum. When
10 oxygen were fired with 4 ammonia, there were ²⁵/₃₇ of the oxygen
left, and there was a deficiency of azote amounting to ¹/₁₂ of what was
expected from the ammonia, owing no doubt to nitrous acid generated
by the explosion. When 10 oxygen to 1.8, or from that to 2.2 ammonia
are used, there is a surplus of about ¼ or ⅓ of the hydrogen contained
in the ammonia, left in the residue of the gas. When the ammonia is
between 13 and 14 there is usually a trace of oxygen or hydrogen as
it approaches either of these limits. By the theory of volumes, 10
oxygen should saturate 13⅓ of ammoniacal gas. I have not any instance
of hydrogen being left when 14 ammonia were used, though there ought
to be ¹/₂₀ of the whole left; and much smaller quantities than that
are appreciable by well known methods. The azote resulting from the
decomposition of ammonia is usually very nearly ½ the volume of the
ammonia.
On the whole the results from firing ammonia and oxygen gas appear to
me more satisfactory than those obtained from nitrous oxide and nitrous
gas, as they are more simple and less perplexed with any theoretic
views.
It may be proper to remind the reader that when we speak of 10 parts
of one gas uniting with 8, 10, or more, of another in the above and
other cases, it is to be understood of gases _absolutely pure_; not
that we ever obtain them in that state, but approximating as near as we
can to it, we mix given portions of such gases as we can obtain, and
then in our calculations of results deduct for the impurities.
One source of uncertainty in these experiments on firing mixtures of
ammonia, is that the real quantity of ammoniacal gas operated upon
is not known. If a certain measure of ammonia be transferred through
mercury ever so dry, some portion of it gets entangled in the mercury,
and 100 measures become perhaps 95: now in the explosion it is a
question whether any part of the 5 measures absorbed is decomposed.
I have marked this attentively, and am persuaded that generally
speaking, little if any of that portion is decomposed; but some trace
of it appears mostly afterwards in the residue as it is liberated from
the pressure of its own kind of gas, and hence easily rises into the
gaseous mixture. Notwithstanding, when the loss of gas by transfer
amounts to 10 or 20 per cent., I have reason to believe that some part
of it suffers combustion occasionally.
_Volume of gases from the decomposition of ammonia._--It has been
observed (vol. 1. Ammonia) that Sir H. Davy obtained 180 measures of
gases, by means of electricity, from 100 of ammonia as the maximum when
the operation was performed with great care, and Dr. Henry in like
circumstances, produced 181, whilst I found 187 measures; since that,
as has been related, Dr. Henry has found 200 measures. It is not easy
to account for these differences; I am inclined to the opinion that the
volume of gases is very nearly doubled, but probably rather less than
more. I find the experiments on the rapid combustion of ammonia agree
best with that opinion.
_Decomposition of ammonia by a red heat._--A short time since I
repeated the decomposition of ammonia by passing the gas through a red
hot copper tube. The proportion of azote to hydrogen, due allowance
being made for a minute portion of atmospheric air, was upon the
average of a number of experiments, 26 of the former to 74 of the
latter.
_Decomposition of ammonia by oxymuriatic acid._--I have made several
experiments on this mode of decomposition since the results published
in vol. 1, page 435. It is well known that a solution of oxymuriate
of lime decomposes ammoniacal salts; water and muriatic acid are
produced, azote liberated, and the acid previously combined with the
ammonia is evolved. But this is not all; an excessively pungent gas or
perhaps vapour is produced, exciting sneezing, and inducing catarrh;
the constitution of this vapour is not well understood; it is never
formed, as far as I know, without the presence of both oxymuriatic acid
and ammonia. The results of such mixtures are of course complicated and
likely to be unsatisfactory; it may notwithstanding be useful to relate
some of them.
When clear oxymuriate of lime solution, and a salt of ammonia are mixed
together with a little excess of oxymuriate, the ammonia is mostly
decomposed, the oxymuriate being converted into muriate of lime by the
hydrogen of the ammonia, whilst the azote is evolved, and the acid
previously combined with the ammonia is liberated; hence oxymuriatic
acid gas is also liberated along with the azote; and it is required to
be taken out before the azote can be estimated. This circumstance may
be obviated by previously adding the requisite quantity of pure potash
or soda, to engage the acid, or by leaving a little undissolved lime in
the oxymuriatic solution. I could never obtain a volume of azote equal
to half that of the ammonia (supposed to be in a gaseous state) though
it is universally allowed not to be less than that, if the whole of the
azote be evolved; on one occasion only I got so much as ¹⁴/₁₅ of that
quantity. The residue of liquid has the extremely pungent smell; but
the azotic gas after passing through pure water has no smell. When this
experiment is made over mercury, the oxymuriatic acid acts upon it, and
hence the excess of oxymuriate should be such as to leave a portion of
that undecomposed at the conclusion.
When the object is to ascertain the hydrogen in ammonia, a portion
of salt known to contain a given weight of ammonia is to be treated
with oxymuriate of lime solution, the strength of which is accurately
determined by means of green sulphate of iron, or otherwise. The
ammoniacal salt in solution is then to be mixed with a moderate
redundance of the oxymuriate liquid, and with a few drops of caustic
potash, and the mixture must be repeatedly agitated for some time. At
length the liquid must be tested by the green sulphate of iron, and
hence the quantity of acid spent upon the ammonia will be determined.
I have mostly found the hydrogen this way below the common estimate,
allowing the ammoniacal salts to be correctly determined.
SULPHURET OF CARBON.
Since the article at page 462, vol. 1, was written, an excellent essay
on the sulphuret of carbon has been published in the Philosophical
Transactions, (1813) by Professor Berzelius and Dr. Marcet. After an
extensive series of experiments, they infer the atom of the sulphuret
to consist of 2 atoms sulphur and 1 of carbon. The investigation did
not seem to warrant their including hydrogen in the atom. I have made
several experiments on the combustion of the vapour of sulphuret of
carbon in oxygen gas by electricity. My method generally was, to
vapourize a given portion of atmospheric air over mercury, taking
care that the vapour was below the maximum for the temperature; this
is easily effected by putting the liquid into a phial of air, drop by
drop, and inverting it over mercury till the liquid is evaporated.
This vapourized air, I find may be transferred through mercury with
very little loss, and even through water several times, without a
total condensation of the vapour. The vapour of ether is much more
condensible by water than that of sulphuret of carbon. A given portion
of this vapourized air is to be mixed with oxygen gas, in Volta’s
eudiometer, and then exploded by the electric spark over mercury. One
volume of vapour combines with nearly 3½ of oxygen, and therefore
requires 4 or 5 times its bulk of that gas before firing, in order
that the combustion may be complete. The results of the combustion are
carbonic acid and sulphurous acid; and I suspect a small portion of
water; though Professor Berzelius and Dr. Marcet could not detect any.
By evaporating a given weight of the sulphuret of carbon, in a given
volume of atmospheric air, at the temperature of 60°, I find the
specific gravity of the vapour to be 2.75 nearly, air being 1. Now if
we assume the atom of vapour to be nearly of the same volume as that of
hydrogen, and to consist of 1 atom hydrogen, 2 sulphur, and 1 carbon,
it will require 7 atoms of oxygen to form water, sulphurous acid, and
carbonic acid, which will accord very well with my experience. When
vapourized hydrogen gas is electrified for some time, there is no
change of volume, though there is some appearance of decomposition.
Probably the hydrogen of the sulphuret is liberated. It is difficult
to conceive how so volatile a liquid as the one in question, could be
constituted out of sulphur and carbon without the addition of hydrogen.
POTASSIUM, SODIUM, &c.
Two views of the nature of these bodies have been given in vol. 1,
(see pages 260, and 484, &c.). In the former they are considered as
simple metals; in the latter, as compound bodies resulting from the
abstraction of oxygen from the hydrates of potash and soda; or as being
constituted of 1 atom of hydrogen united to 1 atom of pure potash or
soda respectively. Those who have had the most experience on these
elements, Sir H. Davy, and M. M. Gay Lussac and Thenard, seem now to
concur in the former view, and it has been adopted by most chemists.
Part of the objections which we made to this view have been obviated,
it should seem, by establishing the fact, that oxymuriatic gas and
hydrogen gas united, form muriatic acid gas. There are still, however,
difficulties to remove before this view can be considered perfectly
satisfactory; but they are not greater perhaps than would attach
to any other explanation of the facts connected with the subject.
Besides potassium and sodium, experience as well as analogy would seem
to render probable, if not to establish, the existence of barium,
strontium, and calcium as metals, of which barytes, strontites, and
lime are the protoxides, as potash and soda are of the other two
metals; (other oxides of potassium and sodium are stated, see page
55-57); barium has a deutoxide, and probably calcium likewise. The
rest of the earths, as magnesia, alumine, silex, &c. are by analogy
considered by most chemists as oxides of particular metals, but the
proportions of their elements have not been determined.
ALUM.
At page 531, vol. 1, we have given the constitution of this important
salt, as under: since that time Mr. R. Phillips has announced another
view of it; and Dr. Thomson has published one differing from both of
these. They are as follow:
_Dalton_-- 1 atom sulphate of potash.
4 atoms sulphate of alumine.
30 atoms water.
_Phillips_-- 1 atom bisulphate of potash.
2 atoms sulphate of alumine.
22 atoms water.
_Thomson_-- 1 atom sulphate of potash.
3 atoms sulphate of alumine.
25 atoms water.
Notwithstanding these differences, there is a near approximation in all
three, in regard to the quantities of acid, alumine, potash, and water
in the salt. This is accounted for partly in the different relative
weights of the atoms, as estimated by the different analysts, but
chiefly in that of alumine.
Some very curious results occurred to me about 10 years ago in
analysing alum; they were new to me, but I have since found they had
been previously discovered by Scheele. (See his essay on silex, clay,
and alum, 1776.) As his observations are not to be found in any of our
elementary books that I have seen, I shall give the particulars of my
own experiments here.
I take 24 grains of alum and dissolve them in water; of these 8 grains
may be allowed for sulphuric acid, ⅕ of which = 1.6 grain = 1.1 grain
of lime = 880 grains of lime water, such as I commonly use. To the
solution of alum I put 880 grains of lime water; a slight precipitate
appears which soon becomes redissolved almost completely. The liquid is
then acid by the colour test.
To this liquid I put 880 more of lime water, and agitate; a copious
precipitate appears and continues; after subsidence the clear liquid is
still acid by the colour test.
Another 880 grains are added, and the whole is then well agitated; the
agitation is repeated two or three times after the precipitate has
partly subsided, so as to diffuse it equally again through the liquid;
finally, the clear liquid is found to be neutral by the colour test,
and to contain no alumine; for, lime water produces no precipitate when
poured into it.
Another 880 grains being added, and the whole stirred well, the clear
liquid after the subsidence of the precipitate is still neutral by the
colour test.
The fifth portion of 880 grains being then added, and the mixture well
agitated, a considerable portion of the precipitate will evidently
disappear, and the mixture become semitransparent; after a time the
clear supernatant liquid is found strongly alkaline; a little of it
touched with an acid becomes milky, and adding more acid clears it
again. The liquid is now 1.0025 sp. gr., or a little heavier than lime
water.
The sixth portion of 880 grains being now added to the whole mixture,
and agitated, the precipitate rather diminishes, and an increase of
specific gravity takes place in the liquid; it is now 1.003.
The seventh and last portion of 880 grains being added to the mixture,
and agitation being continued for some time, a dense bulky precipitate
is formed, which falls with great celerity, carrying with it the
greatest part of the acid, the alumine and the lime, and leaving the
liquid of the sp. gr. 1.0012. It is a subsulphate into which acid,
potash, lime and alumine enter, as will be shewn.
These phenomena appear to me to be best explained by adopting a
constitution of alum, such as to make it consist of 1 atom bisulphate
of potash and 3 atoms of sulphate of alumine; after which the following
explanation will apply.
The first portion of lime water saturates the excess of acid.
The second portion throws down a correspondent portion of alumine. The
clear liquid is acid, because it contains sulphate of alumine, which is
essentially acid by the colour test, because alumine is not an alkaline
element.
The third portion throws down another portion or atom of alumine; but
by continued agitation the two atoms of alumine liberated, join the
remaining atom of sulphate of alumine, and the whole compound falls
down, being then the common subsulphate of alum. Hence the liquid,
containing nothing but sulphate of lime and sulphate of potash, is
neutral by the test, and yields no alumine by the addition of lime
water.
The fourth portion of lime water being put in and duly agitated, the
atom of sulphuric acid is drawn from the subsulphate to join the lime,
and then the floating subsulphate of alumine becomes pure alumine, and
the clear liquor is still neutral.
The fifth portion of lime water tries to decompose the sulphate of
potash, but is unable of itself; however, the floating alumine assists
it, and by double affinity the potash leaves the acid to join the
alumine, and the lime takes the acid. Hence as ⅓ of the alumine enters
into solution with the potash, the precipitate is less copious, and the
liquid is alkaline; a small portion of acid put into the clear liquid
engages the potash, and liberates the alumine, but a larger portion
redissolves the alumine also.
The sixth portion of lime water seems to complete the effect which the
fifth commences, and hence the density of the liquid increases, whilst
the precipitate rather diminishes.
The seventh portion of lime, together with the sixth, after due
agitation and some time, unite the lime with the alumine, one atom of
each, and form a precipitate which would fall together, were no other
compound present, as I found, and Scheele before me; but if sulphate of
lime be present, each compound atom of lime and alumine, unites with
one of sulphate of lime, and the whole descends together, forming a
subsulphate resembling that of alum, only two atoms of lime are found
as substitutes for two atoms of alumine. This subsalt is very little
soluble in water.
According to this view, if 2 atoms of alum were decomposed, 4 atoms of
subsulphate would be formed, each consisting of 1 acid, 2 lime, and
1 alumine; also 2 compound atoms of potash and alumine, and 6 atoms
sulphate of lime. But in the final arrangement, it would seem, that 2
atoms of sulphate of lime are again decomposed, and sulphate of potash
formed, the 2 atoms of lime combining with the 2 of alumine, and then
two more atoms of subsulphate are formed, and the final arrangement is
6 atoms subsulphate precipitated, and 2 atoms sulphate of potash, and 2
sulphate of lime remain in solution.
The facts above stated appear to me to place the constitution of alum
in a clearer point of view than any other I have seen. They make no
difference in the weights of the several elements in 100 grains of the
salt, from what we have given in Vol. 1; only the weight of the atom of
alumine is here taken to be 20 instead of 15, and we have 3 atoms of it
in 1 of alum, instead of 4, as in the former account.
ON THE PRINCIPLES OF THE ATOMIC SYSTEM OF CHEMISTRY.
It is generally allowed that the great objects of the atomic system
are, 1st to determine the relative weights of the simple elements;
and 2d to determine the _number_, and consequently the weight, of
simple elements that enter into combination to form compound elements.
The greatest _desideratum_ at the present time is the exact relative
weight of the element hydrogen. The small weight of 100 cubic inches
of hydrogen gas, the important modifications of that weight by even
very minute quantities of common air and aqueous vapour, and the
difficulties in ascertaining the proportions of air and vapour in
regard to hydrogen, are circumstances sufficient to make one distrust
results obtained by the most expert and scientific operator. The
specific gravity of hydrogen gas was formerly estimated at ⅒ that of
common air; it descended to ¹/₁₂.₅, which is the ratio we adopted
in the Table at the end of Vol. 1. it is now commonly taken to be
¹/₁₄.₅, and whether it may not in the sequel be found to be ¹/₁₆.₅
is more than any one at present, I believe, has sufficient data to
determine. The other factitious gases have mostly undergone some
material alterations in their specific gravities in the last twenty
years, several of which I have no doubt are improvements; but when we
see these specific gravities extended to the 3rd, 4th, and 5th places
of decimals, it appears to me to require a credit far greater than
any one of us is entitled to. In the mean time, it may be thought a
fortunate circumstance, that the weight of common air has undergone
no change for the last thirty or forty years; 100 cubic inches bring
estimated to weigh 30.5 grains at the temperature of 60°, and pressure
of 30 inches of mercury: (whether this is exclusive of the moisture I
do not recollect.) It is also a fortunate circumstance, (provided it be
correct) that this weight is nearly free from decimal figures. I may
be allowed to add, that according to my experience, the weight of 100
cubic inches of air is more nearly 31 grains than 30.5. I apprehend
these observations are sufficient to shew that something more remains
to be done before we obtain a tolerably correct table of the specific
gravities of gases; the importance of this object can not be too highly
estimated.
The combinations of gases in equal volumes, and in multiple volumes, is
naturally connected with this subject. The cases of this kind, or at
least approximations to them, frequently occur; but no principle has
yet been suggested to account for the phenomena; till that is done I
think we ought to investigate the facts with great care, and not suffer
ourselves to be led to adopt these analogies till some reason can be
discovered for them.
The 2d object of the atomic theory, namely that of investigating the
_number_ of atoms in the respective compounds, appears to me to have
been little understood, even by some who have undertaken to expound the
principles of the theory.
When two bodies, A and B, combine in multiple proportions; for
instance, 10 parts of A combine with 7 of B, to form one compound, and
with 14 to form another, we are directed by some authors to take the
smallest combining proportion of one body as representative of the
elementary particle or atom of that body. Now it must be obvious to
any one of common reflection, that such a rule will be more frequently
wrong than right. For, by the above rule, we must consider the first
of the combinations as containing 1 atom of B, and the second as
containing 2 atoms of B, with 1 atom or more of A; whereas it is
equally probable by the same rule, that the compounds may be 2 atoms
of A to 1 of B, and 1 atom of A to 1 of B respectively; for, the
proportions being 10 A to 7 B, (or, which is the same ratio, 20 A to 14
B,) and 10 A to 14 B; it is clear by the rule, that when the numbers
are thus stated, we must consider the former combination as composed
of 2 atoms of A, and the latter of 1 atom of A, united to 1 or more of
B. Thus there would be an _equal_ chance for right or wrong. But it is
possible that 10 of A, and 7 of B, may correspond to 1 atom A, and 2
atoms B; and then 10 of A, and 14 of B, must represent 1 atom A, and 4
atoms B. Thus it appears the rule will be more frequently wrong than
right.
It is necessary not only to consider the combinations of A with B,
but also those of A with C, D, E, &c.; as well as those of B with
C, D, &c., before we can have good reason to be satisfied with our
determinations as to the _number_ of atoms which enter into the various
compounds. Elements formed of azote and oxygen appear to contain
portions of oxygen, as the numbers 1, 2, 3, 4, 5, successively, so
as to make it highly improbable that the combinations can be effected
in any other than one of two ways. But in deciding which of those two
we ought to adopt, we have to examine not only the compositions and
decompositions of the several compounds, of these two elements, but
also compounds which each of them forms with other bodies. I have spent
much time and labour upon these compounds, and upon others of the
primary elements carbone, hydrogen, oxygen, and azote, which appear to
me to be of the greatest importance in the atomic system; but it will
be seen that I am not satisfied on this head, either by my own labour
or that of others, chiefly through the want of an accurate knowledge of
combining proportions.
NEW TABLE OF THE RELATIVE WEIGHTS OF ATOMS.
At the close of the last volume, the weights of several principal
chemical elements or atoms were given; but as several additions and
alterations have been educed from subsequent experience, it has been
judged expedient to present a reformed table of weights.
SIMPLE ELEMENTS.
Weights.
Hydrogen 1
Azote 5±, or 10?
Carbone 5.4
Oxygen 7
Phosphorus 9
Sulphur 13, or 14
Calcium 17?
Sodium 21
Arsenic 21
Molybdenum 21, or 42?
Cerium 22?
Iron 25
Manganese 25
Nickel 26
Zinc 29
Tellurium 29, or 58?
Chromium 32
Potassium 35
Cobalt 37
Strontium 39
Antimony 40
Iridium 42
Palladium 50
Uranium 50, or 100?
Tin 52
Copper 56, or 28?
Rhodium 56
Titanium 59?
Gold 60±
Barium 61
Bismuth 62
Platina 73
Tungsten 84, or 42?
Silver 90
Lead 90
Columbium 107? 121?
Mercury 167, or 84?
SIMPLE OR COMPOUND?
Weights.
Fluoric Acid 10? 15?
Magnesia 17
Alumine 20
Glucine 23? 34?
Lime 24
Oxymuriatic Acid
(chlorine) 29, or 30
Muriatic Acid} 30, or 31
Gas}
Zircone 45
Silex 45?
Yttria 53? 36? 18?
COMPOUND ELEMENTS.
Weights.
Ammonia 6? 12? 13?
Olefiant Gas 6.4? 12.8?
Carburetted Hydrogen
or Pond Gas 7.4
Water 8
Phosphuretted Hydrogen 10
Nitrous Gas 12, or 24?
Carbonic Oxide 12.4
Sulphuretted Hydrogen 15
Deutoxide of Hydrogen 15
Nitrous Oxide 17
Nitrous Acid 19, or 38?
Carbonic Acid 19.4
Sulphurous Oxide 21
Phosphoric Acid 23
Sulphurous Acid 28
Protoxide of Arsenic 28
Soda 28
Hydrate of Lime 32
Protoxide of Iron 32
Protoxide of Manganese 32
Protoxide of Nickel 33
Sulphuric Acid 35
Sulphuret of Arsenic (native) 35
Hydrate of Soda 36
Oxide of Zinc 36
Carbonate of Magnesia 36.4
Protosulphuret of Iron 39
Deutoxide of Manganese 39
Oxide of Chromium 39
Muriate of Magnesia 39
Protosulphuret of Nickel 40
Protosulphuret of Lime 41
Carbonate of Lime 43.4
Protoxide of Cobalt 44
Strontites 46
Muriate of Lime 46
Chromic Acid 46
Protoxide of Antimony 47
Carbonate of Soda 47.4
Hydrate of Potash 50
Muriate of Soda 50
Sulphate of Magnesia 52
Sulphuret of Antimony 54
Sulphate of Alumine (simple) 55
Oxide of Palladium 57
Sulphate of Lime 59
Protoxide of Tin 59
Carbonate of Potash 61.4
Hydrosulphuret of Antimony 62
Nitrate of Magnesia 62
Sulphate of Soda 63
Protoxide of Copper 63
Muriate of Potash 64
Deutoxide of Tin 66
Protosulphuret of Tin 66
Oxide of Gold 67
Barytes 68
Muriate of Lime 69
Oxide of Bismuth 69
Deutoxide of Copper 70
Nitrate of Soda 73
Sulphuret of Gold 74
Protosulphuret of Bismuth 76
Sulphate of Potash 77
Oxide of Platina 80?
Nitrate of Potash 87
Carbonate of Barytes 87
Muriate of Barytes 90
Oxide of Silver 97
Protoxide of Lead 97
Minium 98
Sulphate of Barytes 103
Deutoxide of Lead 104
Protosulphurets of
Lead and Silver 104
Nitrate of Barytes 113
Protoxide of Mercury 174?
Deutoxide of Mercury 181?
Protosulphuret of Mercury 181
Alum 277
ADDENDA.
STEEL.--Since writing the article at page 214, I have had an
opportunity of analysing the crystalline steel, formed by Mr.
Macintosh’s process of cementation by means of coal gas. I dissolved
21 grains of this steel in sulphuric acid, with only a very slight
excess of acid. The whole was dissolved except about ⅒ of a grain of
silvery-like particles. The gas obtained amounted to 29.6 cubic inches.
It yielded no trace of carbonic acid. When fired with oxygen it yielded
3 per cent. upon the volume of hydrogen of carbonic acid; and this
arose, as I ascertained, from the hydrogen containing 3 per cent of
carburetted hydrogen gas: it contained no carbonic oxide. Supposing the
carbone to have been combined with the iron, it would amount only to
about ⅝ of a grain, to 100 grains of iron. Whether such a quantity can
be deemed an essential or an accidental ingredient of steel, may be a
subject of consideration.
_By a mistake of the Printer, the following paragraphs were omitted
after page 308._
EXAMPLE.
According to the following values of the different specific gravities,
(of the accuracy of some of which there may be doubts) and referring
to my essay on oil gas (Manchester Memoirs, Vol. 4, new series, page
79,) we may take the oil gas, which, when the incombustible portion was
abstracted would be nearly .812 sp. gravity, and
100 pure gas give 152 carb. acid and take 248 oxygen;
Here _w_ = 100, _a_ = 152, _g_ = 248, _S_ = 1.458, ∫ = .555, _c_ = .972
_s_ = .0694 and _C_ = .812. The value of _u_ reduces to the following
form;
_u_ = 4.7916_a_ - 1⅔_g_ + 1.875_w_ - 6_C__w_
-------------------------------------------- = 24.5
.625
hydrogen per cent. of pure combustible gas.
Hence we have 75.5 volumes left for the 3 other ingredients = _w_ of
the formula; and abstracting 12 + from the oxygen on account of the
hydrogen, _g_ = 236, and _a_ = 152 as above.
Whence _x_ = Superolefiant = 38¼
_y_ = Carb. hydrg. = 30.2
and _z_ = Carb. oxide = 7+
-----
75.5
These results differ considerably from those deduced in the above
essay; probably in part from errors in the above estimates of the
specific gravities of one or more of the gases.
EXPANSION OF LIQUIDS BY HEAT.
I am not aware of any particular labour that has recently been given
to the enquiry how far pure liquids accord with each other in the law
which I announced as derived from the experiments on water and mercury,
and corroborated by those upon several other liquids. See Vol. 1, Table
of temperature, page 14; also page 36, and following.
Perhaps all liquids should be considered as _pure_ that are subject to
uniform congelation at certain temperatures on the one hand, and on the
other are capable of being distilled by heat without any alteration in
their constitution. Water and mercury will rank in the first place;
alcohol of .82 specific gravity and ether of .72; concentrated
sulphuric acid; nitric acid of 1.42 specific gravity: naphtha and oil
of turpentine, &c. will probably be thought to claim the next place.
It is desirable that the temperatures at which these liquids congeal
should be ascertained; also whether any decomposition is effected by
the operation. If these expand proportionally to a scale of square
numbers for certain given equal or unequal intervals of temperature,
it may point out something relative to the collocation of the ultimate
particles in liquids. The apparent coincidence of this rate of
expansion in liquids, with the geometrical progressive force of steams
or vapours creates an additional interest. It may be that most or all
of these supposed relations are accidental, and only approximative
like that of the rate of expansion of air and mercury, between the
temperatures of -40° and 212°; but I cannot think this probable. Even
should they be only approximations, they are of sufficient utility to
be kept in view.
_FINIS._
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A NEW SYSTEM OF CHEMICAL PHILOSOPHY.
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Published by G. Wilson, Bookseller, Essex Street, Strand, London.
_ESSAYS, by the same, in the Memoirs of the Literary
and Philosophical Society, Manchester._
VOL. 5. PART 1.--Extraordinary facts relating
to the vision of colours.
PART 2.--Experiments and observations to
determine whether the quantity of rain and dew is equal
to the quantity of water carried off by the rivers, and
raised by evaporation; with an enquiry into the origin
of springs.
Experiments and observations on the power of fluids, to
conduct heat, with reference to Count Rumford’s seventh
essay on the same subject.
Experiments and observations on the heat and cold
produced by the mechanical condensation and rarefaction
of air.
Experimental essays on the constitution of mixed
gases; on the force of steam or vapour from water and
other liquids, in different temperatures, both in a
Torricellian vacuum, and in air; on evaporation; and on
the expansion of gases by heat.
Meteorological observations made at Manchester,
from 1793 to 1801.
VOL. 1. _Second series._--Experimental enquiry
into the proportions of the several gases or
elastic fluids constituting the atmosphere.
On the tendency of elastic fluids to diffusion through each
other.
On the absorption of gases by water and other liquids.
Remarks on Mr. Gough’s two essays on the doctrine of mixed
gases; and on Professor Schmidt’s experiments on the
expansion of dry and moist air by heat.
VOL. 2. On respiration and animal heat.
VOL. 3. Experiments and observations on phosphoric
acid and on the salts denominated phosphates.
Experiments and observations on the combinations of
carbonic acid and ammonia.
Remarks tending to facilitate the analysis of spring
and mineral waters.
Memoir on sulphuric ether.
Observations on the barometer, thermometer, and rain,
at Manchester, from 1794 to 1818 inclusive.
VOL. 4. On oil, and the gases obtained from it by heat.
Observations in Meteorology, particularly with regard to the
dew-point, or quantity of vapour in the atmosphere; made
on the mountains in the North of England.
On the saline impregnation of the rain which fell during
the late storm, December 5th, 1822--with an appendix
to the same.
On the nature and properties of indigo, with directions for
the valuation of different samples.
_In the Philosophical Transactions of the Royal Society._
On the Constitution of the Atmosphere.--1826.
_In Mr. Nicholson’s Philosophical Journal._
VOL. 5. (Quarto) On the constitution of mixed
elastic fluids, and the atmosphere.--1801.
VOL. 3. (Octavo) On the theory of mixed gases.
5. On the zero of temperature.
6. Correction of a mistake in Dr. Kirwan’s essay on
the state of vapour in the atmosphere.
8. On chemical affinity as applied to atmospheric air.
9. Observations on Mr. Gough’s strictures on the theory
of mixed gases.
10. Facts tending to decide at what point of temperature
water possesses the greatest density.
12. Remarks on Count Rumford’s experiments on the max.
density of water.
13 & 14. On the max. density of water in reference to
Dr. Hope’s experiments.
28. On the signification of the word _particle_
as used by chemists.
29. Observations on Dr. Bostock’s review of the
atomic principles of chemistry.
_In Dr. Thomson’s Annals of Philosophy._
VOL 1 & 2. On oxymuriate of lime.--1813.
3. Remarks on the essay of Dr. Berzelius, on the cause of
chemical proportions.
7. Vindication of the theory of the absorption of gases by
water, against the conclusions of M. De Saussure.
9 & 10. On the chemical compounds of azote and oxygen, and
on ammonia.
11. On phosphuretted hydrogen.
12. On the combustion of alcohol, by the lamp without flame.
On the _vis viva_.
_In Phillips’s Annals of Philosophy._
VOL. 10. (new series). On the analysis of atmospheric air
by hydrogen.