GASOMETRY;
COMPRISING THE LEADING
PHYSICAL AND CHEMICAL PROPERTIES
OF GASES.
vv
GA SOME TRY
COMPRISING THE LEADING
PHYSICAL AND CHEMICAL PROPERTIES
OF GASES.
ROBERT B.UNSEN
PROFESSOR OF CHEMISTRY IN THE UNIVERSITY OF HEIDELBERG.
TRANSLATED BY
HENRY E. ROSCOE, B.A., PH.D.
WITH SIXTY ILLUSTRATIONS.
LONDON
PRINTED FOR WALTON AND MABERLY
UPPER GOWER STREET, AND IVY LANE, PATERNOSTER ROW.
1857.
BRUNSWICK :
PRINTED BY FREDERICK VIEWEG AND SON.
PREFACE.
It was the author's original intention merely to
arrange in a more connected and suitable form,
those methods of gasometric analysis which he
has from time to time published in his various
researches. In following out this idea it was soon
found, that in order to make the processes more
universally available, it was necessary to generalise
many methods which were previously only applicable
to special cases. This involved the execution of
a series of laborious experimental investigations,
a detailed account of which must be given, in
order that the processes described may rest on a
scientific foundation. The materials of gaseous
analysis, otherwise so limited, have thus received
no unimportant additions.
The three equations which the author has
employed for the calculation of the unknown re-
VI PREFACE.
lation existing between the components of a mixture
of three combustible gases of known composition,
and from which the formula afterwards used by
Reiset and Regnault in their celebrated researches
on respiration are deduced, have been increased
by the addition of a fourth equation, obtained
from the volume of aqueous vapour formed by
the combustion of the hydrogen. Hence we are
able to determine by a single combustion -analysis
not only the unknown composition and conden-
sation of a combustible gaseous mixture of four
components, but also the unknown quantitative
relation of four known gases. By this means, as
well as by employing the absorption- together with
the combustion-analysis (as seen on page 182),
the composition of a gas can easily be found
which contains ten constituents, and of these
seven combustible gases.
In the chapter on absorption of gases in
liquids, the author has shown that the original
hypothesis of Henry, not borne out by any of
the previous experiments, is based upon an actual
law; which is found to apply with the greatest
precision when it is remembered, that the tem-
perature has often more influence on the values
of the coefficients of absorption than the nature
of the gas itself.
PREFACE. VII
The absorptiometric methods, based upon this
law, serving as a means of detecting the con-
stituents of a mixed gas, will gradually become
of greater importance in proportion as the coef-
ficients of absorption of gases in -various liquids
are accurately determined. In as much as a large
field lies open for work in this direction, it is to
be hoped that a detailed account of the methods
employed may not be found uninteresting.
ROBERT BUNSEN.
Heidelberg. March 1857.
From the fact that the book now offered to the
English scientific public is the first and only work
on gaseous chemistry, and as the original German
and the English edition appear simultaneously, the
translator's has been a simple task. He has endea-
voured to render the translation as literal and
exact as possible, and the only additions which
be has thought it necessary to make are the
tables IX, X and XI in the appendix, for the
reduction of the constants now almost universally
employed in scientific research to those still par-
tially adopted in England.
VIII PREFACE.
The eudiometers, and other glass apparatus
described in the work may be obtained from
Messrs. Negretti and Zambra meteorological in-
strument makers Hatton Garden.
H. E. R.
London. April 1857.
CONTENTS.
Page
COLLECTION AND MEASUREMENT OF GASES 1
Collection of gases from geysirs or springs 5
Collection of gases issuing with aqueous vapour 7
Collection of atmospheric gases 10
Transference of gases 12
Collection of gases absorbed by liquids 15
Gases from furnaces 17
Quantitative transference of gases 20
Arrangement of a gas laboratory 21
Description of eudiometers employed 23
Method of graduating the tubes 25
Process of etching 27
Method of obtaining the cubic capacities of the tubes ... 30
Description of mercurial trough 33
Processes in gas analysis 35
Primary observations 36
Fundamental calculation 38
Example of the mode of calculation 39
GASOMETRIC ANALYSIS 42
Derivation of formulae 44
Precautions during explosion 46
Determination of aqueous vapour 47
Example of a combustion -analysis 50
Manipulation in the absorption of gases 53
Development of a general formula 54
Special determinations. 1. Nitrogen 58
2. Oxygen 66
X CONTENTS.
Page
Analyses of atmospheric air 71
Special determinations. 3. Carbonic acid 80
4. Sulphuretted -hydrogen .... 83
5. Sulphurous acid 88
G. Hydrochloric acid 89
7. Hydrogen 91
8. Carbonic oxide 94
9. Marsh gas 99
10. defiant gas 103
11. Ditetryl gas 107
Analysis of Manchester coal gas 107
Special determinations. 12. 2Ethyl gas 114
SPECIFIC GRAVITY OF GASES 116
Methods of determining the specific gravity of gases . . . 118
Effusion method 122
Examples of the latter method 125
ABSORPTION OF GASES IN LIQUIDS 128
Derivation of general formulae 130
Determination of the coefficients of absorption 137
Example of the mode of calculation 140
Water freed from air 143
Determination of the coefficients of absorption 144
No. 1. For nitrogen in water 144
2. nitrogen in alcohol 144
3. hydrogen in water 145
4. hydrogen in alcohol 145
5. sethyl gas in water 146
G. carbonic oxide in water 147
,, 7. carbonic oxide in alcohol 147
8. marsh gas in water 147
9. marsh gas in alcohol 149
10. methyl gas in water 150
11. olefiant gas in water 150
12. olefiant gas in alcohol 152
13. carbonic acid in water 152
14. carbonic acid in alcohol 153
15. oxygen in water 153
1C. oxygen in alcohol 158
CONTENTS. XI
Page
No. 17. For nitrous oxide in water 158
18. nitrous oxide in alcohol 159
19. nitric oxide in alcohol 159
20. sulphuretted -hydrogen in alcohol .... 160
21. sulphuretted -hydrogen in water 103
22. sulphurous acid in alcohol 1G4
23. sulphurous acid in water 168
24. ammonia in water 169
25. atmospheric air in water 174
Practical applications of the law of absorption 175
Absorptiometric analysis of a mixture of two gases . . . 178
Absorptiometric analysis a new reagent in gasometry . . 182
Absorptiometric determination of two unknown gases . . 186
Gases absorbed in mineral springs 193
DIFFUSION OF GASES 198
Description of diffusioineter 200
Experimental determination of the laws of diffusion ... 201
Theoretical explanation of the laws of diffusion 219
Experimental verification of the theory 225
Conclusions 230
Diffusion an aid to gasometric analysis 231
Example of the diffusion of marsh gas 233
PHENOMENA OF THE COMBUSTION OF GASES 235
The heat of combustion 235
The temperature of combustion 238
The explosive force of gases 243
Peculiar action of diluents 253
Explanation of catalytic actions 254
Simple relation between the products of combustion . . . 256
APPENDIX.
TABLES FOR THE CALCULATION OF ANALYSES.
I. Table of the tension of aqueous vapour from 2 to
-f 35 C. (Regnault) 265
II. Table for the calculation of the value of (1 -f 0.00366 268
III. Table of the tension of the vapour of absolute alcohol
(Regnault) 274
XII CONTENTS.
Page
IV. Table for the reduction of barometric observations
made upon a glass scale to C 276
V. Table of the specific gravities and composition by vol-
ume of gases 283
Table for the reduction of the pressure of a column of
water to a column of mercury 285
VI. Table of the coefficients of absorption of various gases
in water and alcohol 287
VII. Table for the calculation of the proportion of oxygen
and nitrogen contained in the air 290
VIII. Table for ascertaining the weights of given volumes of
gases 290
IX. Table for the reduction of temperatures from Fahren-
heit's to the centigrade scale 294
X. Table for the reduction of the barometric pressure from
millimetres into English inches 295
XI. Table for the reduction of French measures and weights
to English measures and weights 296
COLLECTION,
PRESERVATION, AND MEASUREMENT
OF GASES.
A he preservation and collection of gases is the first,
and one of the most important operations in gasometry;
and, being accompanied by many experimental difficulties,
special precautionary measures must in every case be
adopted.
For the purpose of collecting gases, it is customary
to make use of small glass vessels, the contents of which,
consisting of either water, mercury, or air. are displaced
by the gas to be collected. Of these three fluids, water
is the one which is capable of the least general appli-
cation. This liquid gives rise to phenomena of absorp-
tion and diffusion, which cause the gas collected over
water to become mixed with varying amounts of atmo-
spheric nitrogen, oxygen, and carbonic acid. The gas
itself, also, dissolves in the water in quantities deter-
mined by the varying solubility, composition, and pres-
sure of its components: thereby causing an alteration not
i
Fig. 1.
2 COLLECTION OF GASES.
only of the total mass , but also of the relative volumes
of its constituent parts.
The larger the volume, and the absorbing surface of
the water is, in proportion to the inclosed mass of gas,
the more considerable will be the impurity thus intro-
duced. In those cases only, in which gases of constant
composition pass continuously through a mass of water,
is this source of error avoided. This condition, however,
is often found in many springs in which the free and
absorbed gases already exist in a state of equilibrium.
In order to collect the gases from such a spring, to
which the experimenter can immediately approach, the
instrument represented by Fig. 1 is employed. The ap-
paratus consists of a small test
tube c having a capacity of about
40 to 60 cbc. This tube is drawn
out at a before the blowpipe, to
the thickness of a straw; and
is fixed by means of a cork, or
a vulcanized caoutchouc tube,
to the funnel b. Instead of the
test tube, a small longnecked
flask may be used, the neck of
which has been similarly drawn
out before the blowpipe.
The first operation is to fill
the apparatus with the spring-
water; this, however, cannot be
done without bringing the water
in contact with the air, whereby the composition of the
gas absorbed in the water would be altered. It is there-
fore necessary to immerse the tube with the mouth of
the funnel upwards, and to suck the water which has
COLLECTION OF GASES. 3
been in contact with the air out of the apparatus, by
means of a small tube reaching to the lowest part, until
the whole has been displaced by other water from the
spring. The gases of the spring may now be allowed to
pass through the funnel into the tube, without any danger
of their being rendered impure. If the bubbles, in rising,
should be stopped in the neck of the funnel, or in the
narrow part of the tube , it is easy to make them ascend,
by tapping the edge of the funnel against any hard sub-
stance.
After the apparatus has been removed from the
spring by means of a small basin, the tube is melted off
at ; this is easily accomplished with the blowpipe, the
moisture on the part of the tube about to be melted
being previously expelled by the flame.
The column of water which rises in the funnel above
the level of the water in the basin, renders the pressure
on the gas less than that of the atmosphere ; hence no
bulging of the glass at the point of fusion can take place.
In order to have both hands free during the fusion, the
mouth blowpipe represented in Fig. 2 is employed. The
Fig 2 . small vessel a which ser-
ves as a lamp, contains
only about 3 grammes of
oil, and is connected with
the blowpipe by means
of a wire which can be
easily bent, and a small
ring fitting on to the
nozzle of the blowpipe.
By slightly bending this
wire, it is easy to give
the flame the requisite form, and length. The cork c
l*
4 COLLECTION OF GASES.
serves as a mouth -piece, so that the whole apparatus
can be held and regulated with the teeth alone. By this
arrangement the flame can he placed at any instant in a
horizontal, vertical, or transverse direction; for the po-
sition of the point of the blowpipe to the lamp, remains
always the same, whichever way the little instrument
may be held.
If the small vessel drawn out before the blowpipe be
not at hand, a common bottle, or flask filled in the man-
ner just described, may be made use of. After the bottle
has been filled, the funnel is removed under the surface
of the water, and in its stead is placed a moistened cork
exactly fitting the neck of the bottle, and covered with
a thin and moistened plate of caoutchouc. In closing the
bottle under water, care must be taken that no liquid re-
mains above the cork. If the cork be now cut off close
to the neck, and covered with a layer of the finest sea-
lingwax, all possibility of the access of impurities from
the air is avoided, unless the sealingwax be cracked by
shaking, or by changes of temperature.
Gases evolved from volcanic lakes, geisers, or boil-
ing springs, can, in general, be collected in the manner
described. It is, however, often necessary to fasten the
apparatus upon a long stick in order not to be inconve-
nienced by the periodical discharge of vapours which
almost always accompany these springs. Should it
happen that the gas from such a hot spring be retained
in the narrow part of the tube, so that it collects in the
funnel, it may easily be driven into the tube by alter-
nately raising the apparatus into the cold air, and de-
pressing it into the hot water. The air expanded, during
the depression, by the heat of the spring, drives a small
quantity of water 'through the narrow opening, and by
GEISERS AND SPRINGS. 5
cooling in the air a similar volume of gas is drawn into
the tube.
In volcanic districts especially, springs are often
found, either in such a state of ebullition and eruption,
or so peculiarly situated, that it is impossible to approach
near to them. In such cases the apparatus represented
in Fig. 3 may be used. This arrangement is also well
Fig- 3.
adapted for collecting the gases from the mud deposited
by any ordinary water. It consists of a funnel c weighted
with lead, attached by a vulcanized caoutchouc to a
long tin tube furnished with a stop -cock, at the end of
which are placed the small collecting tubes ccc. When
the apparatus has been immersed in the spring, and the
water drawn by suction up to the stop -cock 6, the gas
is allowed to collect in the funnel until it possesses a
pressure greater than that of the atmosphere. The stop-
cock b is then opened, and the gas is allowed to pass
through the collecting tubes ccc until all the atmospheric
air has been displaced. These tubes have a capacity
from 40 to 60 cbc., and the narrow ends are again drawn
out, and thickened, at the points at which they are melt-
ed off. Three or four such tubes connected together by
airtight vulcanized caoutchouc joinings, may be advan-
G VOLCANIC GASES.
tageously employed for each operation. After slightly
heating, the system of tubes is closed simply by pressing
the first and last caoutchouc joinings with the fingers;
and as soon as the temperature has again diminished, so
that the atmospheric pressure slightly exceeds that of
the gas in the tubes, they are one by one hermetically
sealed.
Gases liberated from openings in rocks, from the
clefts of glaciers, from furnaces &c. &c. may be thus col-
lected, even when their tension only exceeds the atmo-
spheric pressure by O.l mm of mercury ; and in order to obtain
the gaseous products in a state of purity, it is only ne-
cessary to sink a tube to the depth from which it is desir-
ed to obtain them. When the openings at the end of the
collecting tubes have a diameter not larger than that of
a common pin, the gases pass through rapidly and easily,
under a very small pressure. This occurs with still greater
facility in the case of gases which issue mixed with steam
of considerable tension, as is found in the clefts, as well as
in the fumarole and solfatara plains of active volcanoes.
Under certain circumstances the collection of gases
is accompanied with great inconvenience. In volcanic
districts, for example, where large volumes of steam, and
boiling water are alternately discharged from the ope-
nings; and where the surrounding boiling mud is only
covered by a thin crust of hardened clay, it is adviseable
to test the stability of the ground with a rod in order
to secure a safe retreat in case of a sudden eruption of
hot vapour. The adoption of this precaution is particu-
larly necessary in the dangerous solfatara plains of Ice-
land. If these gases , as is usually the case , contain sul-
phuretted hydrogen, hydrochloric acid, or sulphurous
acid, which are decomposed by tin or lead, it is neces-
ARTIFICIAL JET OF VAPOUR, 7
>ary to make use of a glass delivery tube, instead of a
metallic one, which, otherwise, is most convenient.
Should no natural source of vapour be found suitable
for experiment, an artificial one may be sometimes pro-
duced. For this purpose it is sufficient to bore a hole
in the hot softened fumarole clay, from which a jet of.
vapour generally issues. If a tube be sunk in this hole,
and the surrounding clay tightly stamped down, the gases
may be collected in the following manner. The jet of
vapour passing from the ground through the tube a,
Fig. 4, is led into the divided glass cylinder I half filled
Fig 4 with water, and of
known capacity. The
vapour is thus com-
pletely condensed
by the water, which
is kept as cold as
possible ; whilst the
gas, as soon as the
water is saturated,
passes through un-
altered, and expels
the air from the
cylinder &, and the
collecting tubes cec,
the end d of which
dips under water.
It often happens
that the volume of the permanent gases is very small
compared with that of the aqueous vapour; and that the
whole of the water in the cylinder, is raised to- the boil-
ing point before the air in the apparatus can be com-
pletely expelled by the small amount of permanent gas.
8 GASES WITH AQUEOUS VAPOUR.
Under these circumstances it is necessary to fill the
whole apparatus with water which has been previously
saturated with the gas, by leading a stream of the vapour
through it. In this way the collecting tubes placed in
an inclined position, may be completely filled with gas,
before the water in the cylinder reaches the boiling point;
it is in this case scarcely necessary to allow the gas to
pass through the tubes for any length of time before
melting off with the blowpipe.
It is of great interest, in order to explain certain
important points concerning the theory of volcanoes,
to know approximately
the relation between
the volumes of volca-
nic gases, and the
aqueous vapour is-
suing simultaneously.
The apparatus re-
presented by Fig. 5
serves for this deter-
mination. The cylin-
der is filled up to a
certain height with
water, and the gas
delivery tube b dips a
few millimetres under
the surface of the
liquid. In place of the
small collecting tubes
a strong collodion bal-
loon , of known capa-
city, is fastened tightly
on to the exit tube e.
DECOMPOSITION UNDER PRESSURE. 9
As soon as the delivery tube has been connected with
the tube immersed in the jet of vapour, the length of
time is observed which is required for tilling the balloon ;
and the volume of the condensed water is read off from
the divisions on the cylinder. In order to determine this
volume with accuracy, the delivery tube must be raised
in proportion as the volume of water increases, so that
at the end of the operation, the tube dips only a few
millimetres below the surface of the water in the cylin-
der b. The relation between the volume of the condensed
water, and the gas contained in the balloon, is thus ob-
Fig 6. tained with sufficient accuracy. The tension of
the escaping gases and aqueous vapour, may be
easily determined by simply sinking the delivery
tube communicating freely with the jet of vapour,
into the hot water contained in the cylinder, until
the bubbles of gas cease to rise through the liquid.
The depth of immersion observed, gives the amount
of pressure, above that of the atmosphere, under
which the gas, or aqueous vapour issues.
Many liquids are decomposed at a tempera-
ture above their boiling points, yielding gaseous
products. When it is required to collect these
gases for examination, the decomposition may
be effected in a glass tube, Fig. 6, 'of somewhat
greater diameter than a quill, and from 1 to 2 mm in
thickness. The tube, having been filled with the
liquid, is drawn out at a to a thickened capillary
which is hermetically closed as soon as all the air
has been expelled. The tube is then heated in a
bath of air, water, or oil, and when the decom-
position is complete, it is opened under a bell-jar
filled with water, or mercury. The gas issues
1(1
COLLECTION OF GASES.
from the capillary tube in a fine stream, the evolution
continuing for some time. The success of this operation
depends essentially on the length and diameter of the
capillary tube. If it be so wide that the compressed gas
can escape very quickly, the tube is liable to be broken
by the suddenly expanding gas. When water is employed
to collect the gas, the atmospheric impurities intro-
duced must be accounted for in the analysis. The oxygen
thus introduced as an impurity, is very troublesome when
elayl, methyl, ethyl, or similar bodies are contained in
the gas. In this case, pure water may be replaced by a
solution of pyrogallate of potash, or sulphide of potassium,
and thus access of oxygen prevented. The nitrogen which
is then the sole impurity can easily be determined in the
analysis.
When free gases have to be collected in situations
easy of access, as for instance is the case in researches
on the composition of the atmosphere, or of the gaseous
mixtures contained in mines and caves, a common
flask of a capacity from 2 to 16
ounces,' may be advantageously
employed. The neck of this bottle
is somewhat thickened before the
blowpipe, at a distance of three-
quarters of an inch from the mouth,
and then drawn out to a tube hav-
ing a diameter of 2 min , as represen-
ted at a, Fig. 7. In order to effect
this contraction, the flask must first
be heated at the point at which the
bottle rounds off to the neck. If
the latter be brought directly to
the flame it is almost certain to
VESSELS HERMETICALLY CLOSED. 11
crack off. The neck becomes so strongly heated that it
is impossible to hold it with the hand, and for this
purpose iron tongs (Fig. 8) into which the neek fits, may
Fifr 8 be used. In order to fill the bottle with gas, the
air is sucked out by means of a narrow glass
tube reaching to the bottom, until it is certain
that the previously contained air is replaced by
gas from without. Five or six deep inspirations
are sufficient for this purpose ; and the air drawn
from the bottle, must be removed from the space
.from which the gas is to be collected. The
glass closed by a cork, is then slightly heated
over a spirit lamp; and the heated gas inside
the bottle, is brought into equilibrium with the
outer air by carefully opening the cork for an
instant. The diminished pressure in the vessel
after cooling, prevents the bulging of the glass
during the fusion of the narrow neck.
When gases have to be collected on high mountains,
or other exposed places, great inconvenience is expe-
rienced in melting off the glass, owing to the impossibility
of producing a blowpipe flame even when the atmosphere
is tolerably still. In such cases, in the absence of a tent,
a large plaid is found to be sufficient. This simple co-
vering, which at once serves as a protection against cold,
wind, and rain, is strongly recommended to all those who
are occupied with researches on gases in uninhabited, and
mountainous districts. Under such a plaid, spread out
like a tent, the ends of which are held down by stones
to prevent currents of air, all the operations in which a
flame is necessary may be carried out in exposed situa-
tions, even during storms.
In this way, alone, I was able to collect the volcanic
12
TRANSFERENCE OF GASES.
gases issuing from the fissures in the crater of Heel a
after the great eruption of 1845.
It is unnecessary to close the vessels containing
the gas, before the blowpipe, if it can be analysed
immediately after collecting. A common bottle may
then be used, closed by a soft, airtight cork, over which
a piece of sheet caoutchouc should be drawn. It is not
adviseable to collect the gas in vessels having a greater
capacity than from 40 to 100 cbc., on account of the
difficulty of transferring the gas from larger vessels over
the mercurial trough. But should the gas be received in
vessels which, owing to their size, cannot be brought
below the surface of the mercury in the trough, the neck
of the bottle must be placed under mercury, and the
cork withdrawn, and replaced by another the arrange-
Fig. 9.
ment of which is seen in Fig. V).
The glass tube b, passing through
the cork a, is connected airtight,
with the tube c by means of a
caoutchouc joining dd shewn in
section in the figure. The space in
the caoutchouc between the ends of
the two tubes, is filled by a solid
glass rod fitting loosely into it, so
that free communication between
the tubes b and c can at any time
be established or cut off, by IQOS-
ening or tightening a ligature round
the caoutchouc tube. This arrange-
ment which serves instead of a stop-
cock , but is much more secure, and
may be renewed in a few moments,
or easily placed at any part of the
I'SE OF AIR-PUMP. 13
apparatus , is universally adopted in all investigations on
gases. When the cork has been placed airtight, in the
neck of the bottle under mercury, with the caoutchouc
valves closed, and the tubes I, b^ filled with mercury,
the bottle is set upright. It is then easy to transfer the
gas to the vessels in which it can be measured, by fixing,
by means of caoutchouc joinings, a funnel filled with
mercury on to the tube c x . and a capillary gas delivery
tube, also filled with mercury, on to the tube c. A current
of gas through the exit tubes may be thus continued,
or stopped, at pleasure, by opening or shutting the
ligatures.
Gases issuing with a certain tension from inaccessible
situations, must be withdrawn by means of an aspirator
or hand air-pump. A small air-pump Fig. 10 (see p. 14)
such as is commonly used for desiccation in organic
analysis, answers the purpose completely. The instru-
ment is screwed fast on to the middle of a small board
mi, upon which the experimenter stands during the ope-
ration. The gas is then pumped through the system of
collecting tubes b l> until all the air has been withdrawn.
Many solid substances, soluble in water contain gas
inclosed in their pores, as, for example, the decrepitating
>alt from Wieliczka. The gas thus contained, may be
collected in the following manner. Fifteen to twenty
litres of water is completely freed from air by continuous
boiling, in an open vessel, and kept at such a tempera-
ture that a slight ebullition takes place at that part of
the liquid most exposed to the action of the fire. The
glass tube represented by Fig. 1 together with the funnel,
is then filled with the boiling water, and the mouth of
the funnel placed on the bottom of the vessel. The de-
crepitating salt is now thrown into the boiling water, and
14 GASES ABSORBED BY LJQUIDS.
the mouth of the funnel placed over it. The salt dis-
solves, and the gas is set free, and collects in the vessel c.
When the water under the funnel has become saturated
with the salt, it is easily renewed by rapidly moving the
Fig. 10.
funnel up and down in the boiler. As soon as the col-
lecting tube is filled with gas, it is hermetically sealed
at the drawn out extremity (a. Fig. 1).
In many investigations it is required to determine
the volume, and composition, of gases absorbed by liquids.
The nature of the atmosphere diffused through springs,
rivers, pools, and seas; the alterations which this atmo-
sphere undergoes at various depths; and the relations
which exist between this atmosphere and the living or-
GASES ABSORBED BY LIQUIDS. 15
ganisms contained in it, are all questions which can only
be solved by these determinations. In order to collect
the water for such investigations from different depths,
a flask filled with water (Fig. 11) is sunk by means of a
rod or a string weighted with
lead, to the required depth,
V lr and a long gutta-percha tube
'?\ , reaching to the bottom of
* the flask, serves to suck out
the contained water, until the
whole has been replaced by
water from the particular layer
required. In order to prevent
a reflux of water from the
tube a, a stop -cock b or a
valve of caoutchouc, is attached
to the end of the tube. The
flask is closed by a plate of
caoutchouc bound over its
mouth, through a small slit in
which the tube a passes. The
elasticity of the caoutchouc
plate causes this opening to
shut completely as soon as the tube has been withdrawn;
the flask is therefore closed, and after being filled at the
requisite depth can be drawn up to the level of the
observer. When this has been effected, the caoutchouc
valve , Fig. 12 (see p. 16) previously filled with boiled
water, is quickly connected with the flask, and the ligci-
tures made fast. The tube b containing some water, is
next fastened to the caoutchouc a and this, again, is
connected with a second divided tube c, also furnished
with a caoutchouc valve d. The apparatus is then inclin-
K;
COLLECTION OF ABSORBED GASES.
ed so that some water flows into the bulb b\ this is
boiled for some time, whilst the valve a is shut and the
Fi<>-. 12. valve d open, until the whole of the air
is displaced, and the tubes filled with
vapour of water: the caoutchouc tube c
is then completely closed by a ligature
or a screw-clamp. Immediately on open-
ing the valve a the water in the flask
begins to boil, and the absorbed gases
enter the vacuous space. If the flask be
heated for about an hour and half, not
beyond the temperature of 90 C., the
water continues to boil rapidly, and the
whole of the gas coming in contact with
the boiling water is excelled, and col-
lected in the tube c. By carefully heating
and inclining the body of the flask, the
vapour may be expanded, so as to drive
the boiling water up to the ligature d.
At the instant this takes place the valve
d is closed, the tube c removed from the
bulb 6, and opened under mercury by
carefully loosening the ligature e, and the
volume of the expelled gas is read oft 7 on
the divisions.
The nature of the gaseous educts
often varies with the progressive phases
of a decomposition, as, for instance, in
process of coking ; or in the phenomena
of combustion and decomposition occur-
ring in the strata of a furnace. It is
therefore, in these cases, necessary to
collect a series of specimens of gas during the progress of
GASES FROM FURNACES. 17
the decomposition. To effect this at various depths in
the shaft of a furnace, the arrangement already described
at Fig. 3 may be used. The delivery tube must however,
be replaced by a long tube of wrought iron several inches
in diameter. The tube is fixed by means of a stand in
the centre of the shaft, on to the highest layer of coal,
so that the tube sinks gradually, with the addition of
the fresh layers. A tin tube, of the thickness of a fin-
ger, is soldered on to the upper end of the iron tube,
and carried to the place where the apparatus for collect-
ing the gas has been set up. By melting off, from time
to time, the collecting tubes, and replacing them by new
ones, the gas from any desired depth may be procured.
The condensed volatile products are collected in a gra-
duated cylinder placed before the tubes, which can be
occasionally changed. If a glass tube dipping vertically
under water, be joined to the end of the last collecting
tube, the pressure under which the gas issues at that
spot of the furnace where the tube ends, may be deter-
mined by noting the depth to which the glass tube must
be immersed in order that the current of gas should cease.
If gases of varying composition are liberated from
a closed vessel, they are best collected by the following
Fig. 13.
arrangement .(Fig. 13). The gaseous products evolved
from the retort a pass at first through both the tubes c
2
18 COLLECTION OF GASES.
and b. The tube c is then dipped into a vessel containing
mercury d, so that the gas passes only through the tube b
and the following collecting tubes ee. If it is required
Fig. 14.
to fuse off a tube during the continuation of the process,
the open. caoutchouc tube is closed by pressure, and the
tube c raised out of the mercury, in order that a dimi-
nished pressure may prevent the bulging of the tube on
fusion.
In many investigations on mixed gases , it is neces-
sary to take several samples from the original volume of
gas. The apparatus Fig. 15 serves to collect large vol-
umes of a gaseous product, small portions of which can
be successively withdrawn for examination. It consists
of a cylinder a a filled with mercury, in which the bell-
jar bb can be moved up and down by means of the hold-
er c. The delivery and exit tubes e^e each furnished
with a caoutchouc valve dd^ stand inside this bell -jar.
When the bell -jar is to be filled, it must be sunk as far
as possible in the cylinder a a, care being taken that the
tubes ee, do not dip under the mercury. As soon as the
air has been completely displaced by the current of gas,
the valve d is closed, the bell -jar drawn out of the mer-
cury in proportion as it fills, and when this is accom-
plished, the valve d l is also closed. In order to take a
sample of the gas thus collected, a capillary gas delivery
TRANSFERENCE OF GASES. 19
tube / filled with mercury, is fixed airtight into the closed
caoutchouc valve J, and the end of the delivery tube,
being placed under the vessel in which the gas is to be
Fig. 15.
collected, in the mercurial trough, the valve c^ is slowly
opened.
If the nature of the investigation require the trans-
ference of a given volume of gas without loss , it is ad-
viseable to employ the small mercury gasometer Fig. 16
(see p. 20) which possesses the great advantage of re-
quiring much less mercury than the arrangement just
described. The glass vessel a furnished with a tubulus,
2*
20 TRANSFERENCE OF GASES.
bent upwards, and situated close to the foot of th'e glass,
is connected by a caoutchouc valve with the capillary
delivery tube c. The gasometer placed in a horizontal
Fig. 10.
position, is filled with mercury, whilst the caoutchouc
valve is closed; and on again placing the gasometer up-
right, the gas is collected through the tubulus b which,
if possible, should dip under mercury. When it is re-
quired to transfer the gas wholly, or partially, without
loss, the delivery tube is dipped into mercury under the
vessel in which the gas is to be collected, and a tube e
is fixed so deep in the tubulus Z>, by means of a well-
fitting cork, that the level of the mercury in the tube rises
to about the point /, whilst the surface in the gaso-
MEASUREMENT OF GASES. 21
meter stands at a lower level; as, for instance, at </. The
valve d can now be opened, and it is only necessary to
pour mercury into the tube e, in order to transfer the
whole, or any required portion of the gas into another
vessel. Should the caoutchouc tubing of the valve J, as
is usually the case, remain completely closed even after
the removal of the ligature, the sides must be slightly
pressed together to establish the communication, and by
a greater or less pressure of the fingers the current of
gas may be most exactly regulated.
The volume of gas in the capillary tube is so extreme-
ly small in comparison with that in the gasometer,
that the error incurred by its remaining behind in the
tube may in most cases be considered inappreciable. But
to be free from all error it is only necessary to determine
the volume of the capillary by filling it with mercury, and,
then to allow for this volume in the calculation.
Having thus become acquainted with the most im-
portant operations of collecting and preserving gases, we
can now proceed to describe the methods employed for
their measurement.
All eudiometrical investigations must be conducted
in a situation which is as much as possible protected
from changes of atmospheric temperature; and, at the
same time, light enough to admit of exact measurement
with a telescope. For this purpose, it is desireable to
employ a room, having thick walls, not adjoining heated
chambers, and with one or two large windows having a
north aspect. The temperature of such a gas laboratory
does not alter more than 1 C. in a day, even when
sudden variations of 8 to 12 C. occur in the open air.
The experiments are conducted upon a large table (Fig. 17,
see p. 22) furnished with a rim, and a tube a to carry off
22
GAS LABORATORY.
Fig. 17.
Fig. IS. Fig. -20.
DESCRIPTION OF EUDIOMETERS.
the mercury which is spilled during the operations. Two
upright supports bb, about 1.5 m to 2 U1 high, are firmly
fixed at each end of the table; these supports are fur-
nished with moveable arms cc, which can be placed in any
direction on the table, and serve as holders for the baro-
meter 7s, and the eudiometer //*.
The cathetometer used for read-
ing off the height of the volumes
of mercury in both of these in-
struments is represented in the
figure at pp.
The measurement of the vol-
ume of a gas is effected in eu-
diometers, and absorption tubes,
on which millimetre divisions
have been finely etched; the cor-
responding volumes being after-
wards accurately determined. The
absorption tube Fig. 18 is about
250 mm long, 20 mm in diameter,
and of about 60 cbc. capacity.
The open end, as is seen in the
figure, is furnished with a small
lip, by means of which the mea-
sured volume of gas can be trans-
ferred over mercury, without loss.
The tube Fig. 19 differs from the
first by terminating in a small
retort used for receiving the ab-
sorbing substances. The eudio-
meter Fig. 20 is about 20 mm in
diameter, and from 500 to 600 111111
long, and has a capacity of about
Fig. U.
24 DESCRIPTION OF EUDIOMETERS.
1 60 cbc. Besides this instrument, the glass of which need
only be about 2 mm in thickness, two others of similar
construction, but of larger dimensions are required. One
of these eudiometers having the same diameter and thick-
ness of glass as the first, is from 700 to 800 mm long, the
other contains from 500 to 600 cbc., and is 22 mm in inter-
nal diameter. Platinum wires for passing the electric
spark through the gases, are fused into these tubes, the
wires are bent into the curve of the tube, so that the
ends remain about 1 to 2 mm apart. It is not advise able
to have the wires placed straight across the head of the
eudiometer, as in this case they are very liable to be
bent, in cleaning, or in filling the instrument with
mercury.
Great care must be taken in fusing the wires into
the glass, to prevent the slightest opening between the
glass and the wire, which, although too small to allow
even strongly compressed air to pass through, may still
effect a diffusion of the inclosed gases. These interstices
are best avoided by choosing a glass whose coefficient of
expansion is as nearly as possible equal to that of pla-
tinum. The wires are melted into the glass in the fol-
lowing manner; the eudiometer heated before the glass
blowpipe, is touched at the required point with a white-
hot platinum wire, and as the wire adheres firmly to the
hot tube, a fine thread of glass may be drawn out, which,
when cut off, forms a small opening into which the wire
can be melted. To avoid the contact - action of the pla-
tinum, it is well to amalgamate the wires. This is best
done by bringing them in contact with zinc -amalgam and
hydrochloric acid, as the negative electrode in the circuit
of a galvanic battery. This precaution, however, is scar-
cely necessary, as the surface of the platinum is very
MEASUREMENT OF GASES. 25
soon covered with foreign bodies. Before the tube is
furnished with a scale of divisions, it must be carefully
examined to see if the fusion of the wires has been com-
plete. For this purpose the eudiometer is completely
tilled with mercury, and the open end, dipping under
mercury, is knocked against the bottom of the trough
as forcibly as the brittleness of the glass will permit.
The column of mercury thus receives a sudden downward
motion, and a momentary vacuum is formed at the upper
end of the tube ; if the wires are not properly fused into
the glass, a small bubble of air will be seen to ascend
each time into the vacuous space. The eudiometer, hav-
ing successfully stood this examination, may next be gra-
duated. I employ for this operation a copying machine
of very simple construction.
In the groove a a, Fig. 21 (see p. 26), lies the model-
tube of hard glass 66, with millimetre divisions etched
upon it, from which the eudiometers are graduated. This
tube is fixed firmly down with a straight slip of thin
brass, which is pressed against it by screws ccc, so that
the curvature of the glass rises a little above the edge
of the brass slip. The tube to be graduated dd, covered
with a thin coating of wax, is fastened in a similar man-
ner with two pieces of brass, the edges of which are
separated a few millimetres at the part of the tube on
which the divisions are to be made. The deeply etched
divisions on the normal tube can easily then be transfer-
red on to the waxed surface of the tube dd by means of
the rod, represented in the figure, which has a knife
edge at one end, and a sharp point at the other. This
can be done with great accuracy and rapidity by allow-
ing the sharp point of the rod, guided by the thumb and
fore -finger of the left hand, to pass lightly from one
26
GRADUATION OF TUBES.
division to another on
the normal tube, the
sense of touch, and the
ear, alone regulating the
movement. By a little
practice it is, in this way,
easy accurately to trans-
fer from 50 to 60 divi-
sions per minute, without
once looking at the gra-
duation. The length of
the divisions transferred
to the waxed tube de-
pends upon the distance
between the slips of brass
ee. The longer divisions
for the whole-, and half-
centimetres, are formed
by the knife edge pass-
ing into grooves in the
brass slip, which have
been previously made to
coincide with the divi-
sions by slightly moving
the normal tube. To pre-
vent the thin wax co-
vering on the tube from
being removed by the
pressure of the brass
slips, and the glass thus
laid bare, two small
square rods of brass are
soldered along the edge
PROCESS OF ETCHING. 27
of each slip, pressing on the glass at such a distance that
it matters little if some of the wax be there rubbed off.
In order to etch on to the glass the divisions thus
graven on the wax, some finely powdered fluor spar is
strewed at the bottom of a leaden gutter, Fig. 22 a , and
Fig. 22.
covered with a large quantity of strong sulphuric acid.
The leaden gutter is then heated in several places with
the spirit-lamps bbb until a rapid evolution of hydro-
fluoric acid begins, the lamps are then removed, and the
tube covered with a sheet of paper , is placed above the
mixture , and allowed to remain exposed to the acid va-
pour for from 3 to 15 minutes, according to the hardness
of the glass. The etching is sharp and clear only when
the hydrofluoric acid is anhydrous ; but this can be easily
effected by the presence of an excess of sulphuric acid.
In order to see whether the operation is complete, the
depth of the etching on one of the lower divisions, which
may be destroyed without any detriment to the instru-
ment, is examined with the fingernail. The divisions are
still better etched if the mixture of fluor spar and sul-
phuric acid is not heated at all, and if the tube remains
for several hours exposed to the action of the vapour.
If it be required to divide any given length into a
certain number of equal parts, the arrangement repre-
sented in Fig. 23 (see p. 28) may be used. On a plate
28 GRADUATION OF TUBES.
of hard glass, a system of lines is etched all starting
from a point, and extending to the line al. The use of
this arrangement is best explained by an example. For
instance, in order to divide a length of eleven millimetres
Fig. 23.
into thirteen equal parts, it is necessary to find the point
at which the first line is eleven millimetres distant from
the thirteenth; the brass slip is then placed at this point
parallel to the line a&, and the thirteen divisions trans-
ferred to the waxed tube according to the method just
described.
The etched graduation on the tube cannot be used
as representing the cubic capacity of the instrument ; for
in the first place the calibre of such tubes is not constant
for any moderate length; and, in the second place, the
volume of gas at the closed end of the eudiometer cannot
correspond to the number etched on the divisions.- It is
therefore necessary, in order to determine these cubic
irregularities, to pour the same portion of mercury into
various parts of the tube , and to read off in each case
the height to which the mercury rises on the divided
scale. The error introduced by the supposition that
the tube is cylindrical within the length occupied by
each small column of mercury , is inappreciable.
PROCESS OF CALIBRATION.
29
This operation is conducted in the following manner.
The eudiometer with its closed end downwards, is firmly
fixed in a vertical position, and a measured quantity of
mercury, enough to cover about twenty divisions, is
poured in from a tube. The height of this volume of
mercury is then accurately read off on the graduation,
and in order to avoid heating the mass, as well as to
eliminate the errors arising from parallax, this is best
Fig 24 accomplished by
C? means of a tele-
scope sliding
upon a vertical
support (see Fig.
17 pp). A short
test tube of thick
glass furnished
with a wooden
handle a, Fig. 24,
serves to. contain
the measured
quantity of mer-
cury, and the ex-
cess of the mer-
cury is expelled
from the tube by
means of aground
glass plate, which
ispressedagainst
the ground edge
of the tube in
the manner seen
in the figure. The
measure is filled
30
PROCESS OF CALIBRATION.
with mercury from the vessel b furnished with a glass
tube, and stop -cock; and in order to prevent the forma-
tion of bubbles on the sides of the measuring tube, the
point c is placed at the bottom of the measure. The
mercury is then poured into the eudiometer through a
Fig. 25. long funnel. Any bubbles of air which
remain between the sides of the eudio-
meter and the mercury must be carefully
removed by means of a slip of wood , or
of whalebone. If an iron wire be used
instead of these, the glass is apt to be
slightly scratched, and these almost in-
visible scratches become in time larger,
and give rise to cracks which render the
instrument entirely useless.
110
too
70
.644
....23.3
Iff
Supposing that
the first reading off was at b 23.3 (Fig. 25)
second c 44.0
third d 64.4
fourth e 84.4
the volume of mercury used for the mea-
surement occupied
between /> and c the volume 20.7
c d 20.4
d e 20.0
If the volume of the measuring mer-
cury be supposed to be 20.7 (the largest
amount read off on the instrument) ; the
volume contained up to each of the ob-
served divisions is,
CALCULATION OF VOLUME.
23.3 volume 1 X 20.7 = 20.7
44.0 2 X 20.7 = 41.4
64.4 3 X 20.7 = 62.1
84.4 4 X 20.7 = 82.8.
These 20.7 volumes are however equal to 20.0 vo-
lumes read off between e and d\ therefore one division
between these two points of the scale corresponds to a
20.7
rolume
20.0
= 1.035, and one tenth of a division = 0.1035.
In a similar manner the corresponding volumes are found
for the interval on the scale
from dc - = 1-0147 and 0.10147
bc " = L000 and aiooo and so
By means of these calculations it is easy to find the
volume corresponding to each graduation on the tube. The
results are arranged in a table similar to that given below.
I.
II.
I.
II.
I.
II.
I.
II.
I.
II.
17
34
31.40
51
48.50
68
65.84
1
18
35
3240
52
49.52
69
66.88
2
19
36
33.40
53
50.53
70
67.91
3
20
37
34.40
54
51.55
11
68.95
4
21
38
35.40
55
52.56
72
69.98
5
22
39
36.40
56
53.58
73
71.02
G
23
20.40
40
37.40
57
54.59
74
72.05
7
24
21.40
41
38.40
58
55.60
75
73.09
8
25
22.40
42
39.40
59
56.62
76
74.12
9
2G
23.40
43
40.40
60
57.63
77
75.16
10
27
24.40
44
41.40
61
58.65
78
76.19
11
28
25.40
45
42.41
62
59.66
79
77.22
12
29
20.40
46
43.43
63
60.68
80
78.26
13
30
27!40
47
44.44
64
61.70
81
7930
14
31
28.40
48
45.46
65
62.74
82
80.33
15
32
29.40
49
46.47
66
63.77
83
81.37
10
33
30.40
50
47.49
67
64.81
84
8240
&c.
&c.
32 ERROR OF THE MENISCUS.
The linear divisions are given in column I, whilst
column II gives the corresponding capacity of the tube
according to an arbitrary, but comparable standard. The
immediate readings off represented in the first column,
must then be exchanged for the corresponding corrected
volume in the second column. The volume taken from
the table corresponding to the division read off on the
eudiometer, still requires a slight correction. When the
volume of the eudiometer is determined with the open
end of the tube upwards, the height of the mercury must
always be read off at the highest point of the meniscus,
at a a, Fig. 26; the volume thus read off is not, however,
equal to the total capacity of the tube up to
the division a, that is the volume aab, but
to the volume ccb\ the volume read off is
therefore less than the required volume by the
space a ace. If the instrument be now placed,
as when in use, with the open end downwards,
a volume of gas read off exactly at a will cor-
respond still less to the volume of mercury
cob employed in the graduation, for it is easy
to see that the gas now occupies a space larger
by twice caac than the volume of the gra-
duating mercury. Twice the spaae caac must,
therefore, be added to the volume of the gas
as contained in the table. This volume, ex-
pressed in divisions of the tube , can be deter-
"& mined once for all. This is done by pouring
some mercury into the tube placed with its
closed end downwards , and reading off the height of the
meniscus. A few drops of sublimate solution are now
poured into the tube , and the surface of the mercury im-
mediately becomes perfectly horizontal. Twice the space
PROCESSES IN GAS ANALYSIS. 33
between the first curved surface of the mercury, and the
same surface, rendered horizontal, gives the constant
volume which must be added to each reading off, and
may be called the error of the meniscus.
It is not often required to reduce these determina-
tions of relative volume to absolute measure. Should
this be the case, it is only necessary to know the weight
g and temperature t of a mass of mercury which occu-
pies the volume V used in the graduation. The coef-
ficient of expansion of mercury is 0.0001815 and its spe-
cific gravity at C. 13.596, hence the volume of a redu-
ced division expressed in cubiccentimetres c is found
from the formula
_ g x (1 + 0.0001815 t)
13.596 V
The measurements necessary in gas analysis are best
performed in a small mercurial trough (Fig. 27) about
Fig. 27.
O m 350 long, and O m 080 broad. This trough has two
transparent sides of plate glass, and the bottom and
. 3
34 PROCESSES IN GAS ANALYSIS.
other sides of the trough is made of dense pear wood,
which is well rubbed with sublimate solution and mercury
before use, to ensure adhesion of the metal. The trough
stands on a board c into which is fixed one, or better,
two standards </, for supporting the groove ee lined with
felt, in which the eudiometer lies.
If gas has to be transferred from large vessels, a
similar but larger mercurial trough must be employed.
F . 2g F; 29 Particular precautions must be
taken in filling the eudiometers with
mercury, and in transferring the
gases. The instrument having been
washed out with water, must be
cleaned and dried with filtering
paper. This is best done by a
wooden rod (Fig. 28), which is fur-
nished at the upper end with a num-
ber of points of wire projecting half
a millimetre from the surface of the
wood, and serve to hold the roll of
paper firm. In cleansing the eudio-
meter care must be take to remove
all fine threads of paper so that no
error from their combustion should
ensue on the explosion of the gas.
When practicable, a drop of water
is brought into the head of the tube
thus cleaned, by means of a glass
rod, so that the collected gas is perfectly sa-
turated with aqueous vapour. In order to fill
the eudiometer with mercury, the funnel Fig. 29
containing the metal is placed in the opening
of the reversed instrument. This funnel is
PROCESSES IN GAS ANALYSIS. 35
fastened on to a long fine tube, the end of which reaches
to the bottom of the eudiometer; the mercury issues in
a fine stream, and gradually rises in the tube, forming
a mirror -like surface on the sides of the instrument, to
which one bubble of air now adheres around the pla-
tinum wires. In order to expel this bubble from the
platinum wires the eudiometer is placed with its open
end under the surface of the mercurial trough, and by
knocking the end against the bottom of the trough, the
bubble is detached from the wire, and is seen between
the surface of mercury and the glass. As soon as this
occurs, it is easy to let the bubble rise in the tube, which
is held reversed and closed by the thumb. The mercury
is apt to be thrown about in filling the long eudiometers ;
this is best avoided by sinking the tube to be filled, by
means of strings, into the tube a in the table Fig. 17,
through which the excess of mercury is carried into the
vessel /.
When it is required to transfer the gas from the
collecting tubes into the eudiometer, the closed end of
the tube is broken under mercury, by pressure against
the bottom of the trough ; and the aperture thus made
is brought under the open end of the eudiometer; the
gas is then easily displaced by giving the inclined tube
an oscillating motion, when the gas rises into the eudio-
meter even if the broken aperture is not large.
It often happens that in this operation small bubbles
of air remain hanging between the inside of the tube,
and the mercury. These bubbles must be carefully re-
moved into the gas contained in the upper part of the in-
strument, by setting the column of mercury in oscillation,
so that the upward motion is more rapid than the down-
ward. This is best effected by placing the eudiometer in
3*
36 PRIMARY OBSERVATIONS.
the groove ee, Fig. 27, and giving it a quick downward,
and still quicker upward motion, so that the movement
of the tube is synchronous with the oscillations of the
column of mercury.
If mercury has to he added to that already contained
in the trough, care must be taken to pour, in the metal
at a considerable distance from the eudiometer and ab-
sorption tubes, as bubbles of air may thus be carried
under the mercury into the instruments, even when their
lower ends dip several inches below the surface.
Every determination of the volume of gases requires
the following four primary observations:
1. The level of the mercury in the eudiometer.
2. The level of the mercury in the trough, measured on
the etched divisions on the eudiometer.
3. The atmospheric temperature.
4. The barometric pressure.
All these observations are made by help of the tele-
scope g, Fig. 17, which can be moved up and down upon
a vertical wooden rod. If such a telescope be placed at
a distance of from 6 to 11 feet from the object observed,
the small displacement from the horizontal position, which
is unavoidable with a wooden stand, does not produce
any perceptible amount of parallax, particularly whe-n
the observation is made in the middle of the field of
view. In the first place the highest level of the mercury
meniscus in the eudiometer is read off on the etched di-
visions; and in the second place the level of mercury in
the trough is also read off on the same divided scale.
The first observation gives the volume of gas to be found
in the table, of capacity of the instrument; and the second
observation minus the number read off in the first obser-
vation, gives the height of the column of mercury, which
PRECAUTIONS IN READING OFF. 37
acts in opposition to the barometric pressure, and must,
therefore, be subtracted from that quantity. For the
measurement of the atmospheric pressure the syphon ba-
rometer A, Fig. 17, is employed, placed in a vertical po-
sition in the neighbourhood of the eudiometre. The
height of the mercury is read off on a millimetre scale
which is etched on the two limbs, lying in one vertical
line. The thermometer is also furnished with a scale
etched on the glass ; and rests in the shorter limb of the
barometer supported by a small spring of whalebone. By
means of this arrangement all the observations can be
made from distant positions with very slight alterations
of the telescope.
Before the apparatus has been left to assume a con-
stant temperature it is adviseable to direct the telescope
upon the divisions, which should be cleaned with filter-
paper and rubbed with a little vermilion to render them
more plain. For the purpose of throwing a better light
on the lower divisions, a small paper screen , Fig. 30,
is placed between the mercury
and the glass side of the trough,
and the surface of the mercury
and the divisions of the scale
are seen through a slit m in
the screen. The barometer is
always read off last ; as it then
is necessary to approach the
tubes in order to give the mer-
cury in the barometer a slight
motion, to destroy any adhe-
sion between it and the glass.
This motion can be best ef-
fected by dipping the bulb of
Fig. 30.
38 FUNDAMENTAL CALCULATION.
the thermometer i into the metal in the lower limb of
the barometer.
In order that the alterations of temperature of the
mercury, should coincide as much as possible with those
of the surrounding air, it is well to employ as little of
the metal as possible ; and to allow from half an hour to
two hours to elapse between each observation. The vo-
lumes of gas are always read off with the eudiometer
placed in a vertical position. For this purpose vertical
lines may be drawn on the wall of the room, and by
comparison with these the tube may be placed in the
required position. *
The observed volumes of gas are reduced by calcu-
lation ,to the volumes occupied in the dry state at
centigrade and under a pressure of 1 metre of mercury.
This volume v 1 of dry gas reduced to C. and l m is
found from the equation,
(v + m) (b - b, - b,}
(1 4- 0.00366 *)
in which b represents the height of the barometer, 6 L the
height of the column of mercury rising from the level of
the trough into the eudiometer, t the observed tempe-
rature, b 2 the tension of aqueous vapour* for the tem-
perature t , m the error of the meniscus , and lastly v the
volume of gas found in the table of capacity.
This reduced value v 1 is one which is employed in all
the calculations.
The following measurement of the same volume of
These tensions are found in table I calculated by Rcgnault
from his own experiments- Table II contains the values of
1 -]~ 0.003GG t for a range of temperature from 2 to 40 C.
Table III contains the tension of the vapour of absolute alco-
hol calculated from Kegnault's experiments.
EXAMPLE OF CALCULATION. 39
air first saturated with aqueous vapour, and afterwards
dry, may serve as an example of the calculation.
1. Air saturated with moisture.
Observation at the lower level of mercury . = 565.9 min
Observation at the upper level in eudiometer = 317.3
Height of column Z^ to be subtracted from
barometer = 248.6
The division 317.3 corresponds to a volume
in the table of capacity v =292.7
Correction for the meniscus m = 0.4
Temperature of the air t = 20.2 C.
Height of the barometer b = O m 7469
Tension of aqueous vapour for 202 C. . b. 2 = O m 0176
log. (v +') = log. 293.1=2.46702
4- log. (I l>i b y ) = log. 0.4807 = 0.681871
+compl. log. (1+0.00366 t)=compl. log. 1.0739 = 0.969031
log. 01 = 2.11792
t;i = 131.20
2. The same volume of air dried over chloride of calcium.
Observation at the lower level of mercury . = 565.9
Observation at the upper level in eudiometer- = 310.7
Height of column b v to be subtracted from
the barometer = 255.2
The division 310.7 corresponds to a volume
in the table of capacity v = 286.0
Correction for the meniscus m = 0.4
Temperature of the air * = 20.2 C.
Height of the barometer b = 0.7474
log. (v + m) = log. 286.4 = 2.45697
_|_ log. (b bj) = log. 0.4922 = 0.692141
+compllog. (1 + 0.00366 t)=compLlog.W739 = 0.969031
log. v 1 = 2.11814
40 CORRECTIONS FOR TEMPERATURE.
If the temperature of the gas laboratory, as is usually
the case, only varies one or two degrees during the ope-
rations of a gas analysis, the error arising from the va-
riation in density which the mercury undergoes is so
small that unless the determination is a normal one, it
may be overlooked. When the variations in temperature
exceed these limits, or when it is required to determine
not only the relative, but also the absolute volume of a
gas, the column of mercury (b 6J must be reduced
from the atmospheric temperature to C. by substituting
for (b bi) the expression
in which a represents the coefficient of lineal expansion
of glass = 0.0000092, and /3 the coefficient of cubic ex-
pansion of mercury = 0.0001815. The columns of mer-
cury O m 4922 and O m 4807 in the former example when re-
duced to according to the formula, become O m 49049
and O m 47903. In order to avoid this troublesome calcu-
lation, the table IV in the appendix is employed, in which
the expansion of the glass as well as the mercury is
allowed for. The first vertical division contains the lengths
of the observed columns of mercury for every 5 milli-
metres, and the following divisions contain the amounts
of expansion of these columns for each degree of the
centesimal scale from to 9.
The use of the table is best explained by an example.
Required to reduce the column of mercury 0.7105 observ-
ed at 234 C. to C. The nearest pressure in the table
is found to be 0.7100. The intervals in the table are
so chosen, that the difference between any observed pres-
sure, and the nearest number found in the table is so
EXPANSION OF MERCURY. 41
small, that any alteration of density on this small length,
arising from variation of temperature, is inappreciable.
Hence the numher which must be subtracted from the
pressure 0.7100 to give its length at C. may also be
subtracted from the observed pressure 0.7105 without
exceeding the limit of the observational errors. The
column 0.7105 has then in cooling from 234 to
subtracted
for 20^0 2.4296 mm
30 0.3644
QQ4 0.0186
for 2304 2.8126"""
These 2.8126 mm subtracted from O m 7105 give the length
at Oo to be 0.70769 m .
GASOMETRIC ANALYSIS.
One of the most important problems in gasometry
consists in the determination of the nature , volume , and
condensation of the elementary constituents of a single
combustible gas of unknown composition.
To begin with the most complicated case, we may
suppose the gas contains x volumes of carbon vapour,
y volumes of hydrogon, z volumes of oxygen, and n vo-
lumes of nitrogen; we require therefore four equations
for the determination of the four unknown quantities #,
y, z and n. In order to obtain these four equations it is
necessary to explode a volume V of the gas , and to de-
termine, 1) the contraction C which occurs in the com-
bustion, 2) the aqueous vapour Y formed, 3) the carbonic
acid X produced, and 4) the residual nitrogen N.
The volume of carbon vapour x contained in the unit
volume of gas gives 2# volumes of carbonic acid, V vo-
lumes of gas give therefore 2 x V. Hence we have
X== 2xV
DERIVATION OF FORMULA. 43
The volume of hydrogen y contained in the unit vo-
lume of gas gives y volumes of aqueous vapour. Hence
Y = y V .or y = -pr.
As also n volumes of nitrogen are contained in the
unit volume, of gas, and V volumes contain Vn volumes
of nitrogen, we have
N
N = Vn or n = -=-.
The volume of the gases before the explosion, is
composed of the volume 1 of gas to be examined, together
with the volume of oxygen 6>, which has to be added.
The volume of gas remaining after the explosion, is equal
to the volume of oxygen 0, originally taken, minus the
oxygen 2 x necessary for the formation of carbonic acid,
minus the oxygen */ 2 y required for the combustion of the
hydrogen, plus the carbonic acid 2# produced, plus the
oxygen z contained in the gas, plus the nitrogen n libe-
rated by the combustion of the gas. The volume V of
gas employed, when the values of x and y are substituted,
is found to be:
volume before the combustion V -\- 0,
y
volume after the combustion Vz-\-0-\-XX -\-N.
2
If the first volume be subtracted from the second we
get for the volume of gas which has disappeared the
expression
C=V-V,+ 1. -N or *=i + ^_-_ *.
In order to determine F, X, Y, N and C experi-
mentally, V volumes of gas are brought into the com-
bustion-eudiometer, the amount of oxygen required for
44 DERIVATION OF FORMULAE.
combustion added and the mixture exploded. The vo-
lume of gas which has disappeared after the combustion
is equal to C. The eudiometer is next exposed to a tem-
perature of 100 C. in an apparatus about to be described.
The difference between the reduced volumes before and
after heating is Y, The carbonic acid X is then deter-
mined by means of a potash ball. - - The residual gas
consists of nitrogen mixed with an unknown quantity of
superfluous oxygen. This volume of oxygen, determined
by explosion with hydrogen, subtracted from the residual
gas gives the amount of nitrogen N.
If experiment has shown that oxygen is not contained
in the gas, that is if z = 0, we have,
o-i + JL A *
~ 2V V V
and if the value y V be substituted for Y, we have,
._, + {__,_,(.+*_,)
By means of this equation the volume of hydrogen
contained in the unit volume of a gas free from oxygen
can be calculated from the contraction, without it being
necessary directly to determine the amount of aqueous
vapour Y formed. This method is applicable to hydrogen,
oxygen, nitrogen, and to all gases of the following com-
position :
n vol. C -\- HI vol. N = 1 vol.
n C + n t = 1
n ,; C -J- H! H= I
n H -(- nj 0=1
n // + Hi N =1
n NnO=I
PRECAUTIONS DURING EXPLOSION. 45
n vol. C -)- ??i vol. PI -(- w 2 vol. = 1 vol.
n (7 -(- M! ,, H -\- n 2 JV = 1
n ., //+! +'"2 #=1
??, c -f- ft! 0- -f- w. 2 jv = i
??, C -\- rii ,. // -f 71-2 -|- % vol. ^ = 1 vol.
It is seen that cases occur in which the mixture does
not contain any gases combustible with oxygen, as for
instance and n vol. A 7 -)- ^ vol. 0=1. Such a gas
must be exploded with hydrogen instead of oxygen.
If the original volume is F, that disappeared after ex-
plosion C, and the residual nitrogen A", we obtain the
following equations by similar reasoning.
V (1 + 2 z n) = C
C+NV N
^V~ ~V'
All the combustions of gases required in the analysis
must be conducted in closed eudiometers. The tubes are
best closed for the explosion by means of a plate of cork,
Fig. 31, covered with thick vulcanized caoutchouc, and so
Fig. si. cu ^ that it lies firm on the bottom of
the mercurial trough. The open end of
the eudiometer is pressed against this
cushion, and held tightly down by the
wooden arm of a holder, at the under
surface of which there is a slight hollow lined with cork.
The layer of air, which adheres on to the surface of the
caoutchouc plate under the mercury, may cause the most
serious errors, for on opening the eudiometer after ex-
plosion, the small bubbles of air would be drawn into the
instrument, and mix with the measured contents of the
46 ELECTRICAL APPARATUS.
tube. This source of error can be easily avoided, by
moistening the surface of the caoutchouc with a solution
of corrosive sublimate. A thin film of subchloride of
mercury is produced, which causes a complete ad-
hesion of the metal, and thus prevents the presence of
air bubbles.
The firing of the gaseous mixture is always effected
by the electric spark. A small cylinder about 3 inches
high and 1 broad serves as a Leyden jar. This cylinder
is lined inside with tin foil, but in order to avoid amal-
Fig. 32.
gamation the outer metallic coating consists of platinum
foil. Electrophori or common electrical machines are
very apt to become useless, by remaining in the damp
and cold rooms which are most suitable for gas labora-
tories. The jar is therefore best charged by means of
the simple and effectual arrangement represented in
Fig. 32.
It consists merely of a large porcelain tube, which
when held before the iron wire of the cylinder, and rubbed
with the silk and amalgam*, evolves so much electricity
that the jar is charged in a few seconds.
K The amalgam by aid of which a porcelain tube 3 feet long
and iy 2 inches thick may be made to supply the place of a
tolerably powerful electrical machine, is made as follows. Two
DETERMINATION OF AQUEOUS VAPOUR.
47
The following apparatus serves to measure the amount
of aqueous vapour formed by the combustion. The iron
Fig. 33.
boiler .4, Fig. 33, half fil-
led with water, carries a
long glass cylinder cc,
from the iron lid d of
which hangs the support
ff for the eudiometer e.
The volume of the vapour
of water formed by the
combustion, is measured
by placing the eudio-
meter in the vessel { half
filled with mercury, and
bringing it, by means of.
the supports//, into the
glass cylinder cc, through
which a rapid current of
steam is passed from the
boiler A. The tempera-
ture of lOOo c. thus at-
tained, is amply sufficient
to vaporize the water in
the eudiometer, owing to
it boiling point being
parts of mercury are heated in a common test tube and 1 part
of thin zinc foil, and one part of zinc added whilst the metal is
well stirred. In order to make the amalgam more plastic, it is
melted and stirred several times, and then placed on a pieco
of the thickest and best silk which serves as a rubber. In
rubbing the tube, the silk is so arranged that only half the sur-
face in contact with the porcelain is covered with amalgam, the
remainder being left free. The powerful action of the amal-
gam begins generally after it has been some time in use, and
it preserves its activity often for months.
48
DETERMINATION OF AQUEOUS VAPOUR.
much lowered by the diminution of pressure caused by
the column of mercury in the tube acting in opposition
to the barometric pressure.
I give as an example of such a determination, an
analysis of the gas evolved by the action of four parts of
sulphuric acid upon one part of methylic alcohol, which
was made in my laboratory by M. Quincke. The gas was
washed with water and caustic potash before collection,
and in order to free it from the last traces of sulphurous
acid and carbonic acid gases, it was left for a long time
in contact with solid caustic potash.
For the sake of greater accuracy two portions of
this gas were analysed, but in the first, the amount of
aqueous vapour, and in the second, the amount of nitro-
gen was determined.
Vol.
Pres-
sure.
Te ,np.
0C. and
l m press.
1) Original volume of gas . . .
79.G
0.3140
4.0
24.63
2) After addition of oxygen . .
327.2
0.5615
5.0
180.42
3) After the explosion ....
2G8.7
0.4915
4.9
129.74
4) After heating to 100 C. . .
418.1
0.6752
99.5
206.95
5) Observation 3) repeated . .
2G8.2
0.4914
3.7
129.47
G) After absorption of carbonic acid
193.3
0.4188
0.7
80.75
From these observations we have:
Original volume of gas . . . . V= 24.63 or 1.0000
Contraction after explosion . . C = 50.68 or 2.0576
Aqueous vapour formed . . . Y = 77.35 or 3.1405
Carbonic acid produced . . . X = 48.72 or 1.9781
The volume of gas originally taken in this experi-
ment, as well as the oxygen employed for explosion, were
DETERMINATION OF AQUEOUS VAPOUR. 49
both measured in the dry state by filling into a dessi-
cated eudiometer over dried and warm mercury. All the
columns of mercury are reduced to C.
Observation 4) is obtained from the following expe-
rimental data:
Barometric pressure at 51 C 745.9
Column of mercury in the eudiometer .... 73.0
Column of water above the mercury in vessel i . 22.4
Temperature of the aqueous vapour . . . . . 99.5
Observed volume corrected from the table of capacity 417.0
The column of water 22.4 represents a pressure of
22 4
mercury equal to ' . = 1.7 min .
The column of mercury measured in the eudiometer
73.0 1.7 = 71.3 mm is when reduced to C. equal to
70.1 mm . This quantity subtracted from the barometric
pressure reduced from 51 C. to 0C. 745.3 mm gives G75.2 mm .
The coefficient of cubic expansion of glass between
Oo and 100 C. is according to Dulong and Petit 0.00002583.
The interior of the eudiometer filled with gas 417.0, was
therefore expanded, by heating from C. to i)95 C.,
(1 _|_ 0.0000258 X 99.5) 417.0 = 418.1.
The same analysis repeated for the nitrogen deter-
mination gave:
Vnl at
Vol.
Pres-
sure.
Temp.
C.
V Ol. Uli
C. and
l m press.
1) Original volume of gas . . .
50.6
0.1419
1.4
7.14
2) After addition of oxygen . .
199.8
0.3112
2.6
61.59
3) After the explosion ....
172.4
0.2738
3.7
46.57
4) After absorption of the carb. acid
132.8
0.2409
3.9
31.54
5) After addition of hydrogen
547.3
O.G955
2.6
377.06
G) After the explosion ....
4GG.G
O.G12G
1.5
284.28
4
50 DETERMINATION OF NITROGEN.
Hence :
Original volume of gas ... V = 7.14 or 1.0000
Contraction after explosion . . C = 15.02 or 2.1036
Carbonic acid formed . . . . X = 15.03 or 2.1050
Nitrogen^. , JV = 0.61 or 0.0854
The amount of nitrogen found, is so small that it
must arise either from the unavoidable errors of obser-
vation, or else from the presence of a slight trace of
atmospheric air.
These two analyses give the following mean values :
V = 1.000
= 2.081
Y = 3.141
X = 2.042
N = 0.000
1 volume of gas therefore contains,
if
Carbon vapour . x = -^ =1.021
Hydrogen ...?/ = ... .*"'. m . '';' :/ = 3.141
Oxygen . . . z = ~ (V i/ 2 V N C) = 0.490
Nitrogen . . . n _= N = 0.000
Hence 1 volume of the gas consists of
Found. Calculated.
Carbon vapour . . 1.02 1.03
Hydrogen .... 3.14 3.10
Oxygen ..... 0.49 0.52
As an example of a gas which only contains oxygen
and nitrogen 1 have chosen nitric oxide. This gas was
evolved from nitric acid and copper and was led into a
concentrated solution of protosulphatc of iron. On sub-
ANALYSIS OF NITRIC OXIDE. 51
sequently heating the saturated solution, the gas was
obtained in a state of purity, care being taken not to col-
lect the portions evolved at the end of the operation. As
nitric oxide, contrary to the statements of most of the
handbooks, cannot be exploded with hydrogen, it was ne-
cessary to mix the gas with a known volume of nitrous
oxide. The following numbers were obtained from an
analysis made in this manner.
Vol.
Pres-
sure.
Temp.
C.
Vol. at
C. and
1 press.
Nitric oxide
101 3
02105
44
20.99
Nitrous oxide added
Hydrogen added
2G4.1
423 5
0.3944
05G30
4.6
5 3
102.44
233 90
Alter explosion
2945
04261
5 3
123 10
Oxygen added
After explosion .
351.3
292 5
0.4864
04247
5.3
4.8
1G7.G2
12208
The volume of nitric oxide employed was V= 20.99.
81.45 volumes of nitrous oxide were added; these
81.45 volumes on combustion produce a contraction of
81.45 volumes. The total contraction is however 110.80,
hence that caused by the combustion of the nitric oxide
is C = 110.8 81.45 = 29.35. The gas remaining after
the first explosion 123.10 can only contain nitrogen and
excess of hydrogen. A second explosion with oxygen
gave a contraction of 45.54 ; two thirds of this gives the
volume of hydrogen, 2 3 45.54 = 30.36. The amount of
nitrogen liberated from the nitrogenised gases was there-
fore 123.10 30.36 = 92.74. Of this 81.45 volumes
came from the nitrous oxide, the remainder in the quan-
tity contained in the nitric oxide; N is therefore equal
52 MANIPULATION IN
to 11.29. The following composition is calculated from
F, C, and N by means of the equations
N -
n = and z =
2F
Found.
Calculated.
n = 0.52
0.5
z = 0.47
0.5
0.99
1.0
A second class of eudiometric determinations relates
to the separation of a mixture of known gases. Although
the methods employed vary considerably with the nature
of the gas to' be determined., still the general order of
the processes adopted in gas analysis may here be
detailed.
The analysis is commenced by the absorption of
those gases which are easily decomposed or enter easily
into combination. The analysis of the residual unabsorbed
gas, which usually contains inflamable constituents to-
gether with nitrogen, forms the second part of the in-
vestigation. The first absorption is effected in the small
graduated tube Fig. 18. For the purpose of absorbing
the gases only those substances can be used, the tension
of whose vapour is either exactly determined, or is an
inappreciable quantity. In order to bring these sub-
stances in contact with the gas without admission of air,
they are made into the form of small balls fastened on
to the end of platinum wires, by means of which they can
be pushed up under the mercury into the absorption tube.
These balls when composed of fusible substances
can be most conveniently cast in common iron bullet
moulds in which the canal for pouring in the metal has
been filed off. A platinum wire bent at one end is placed
THE ABSORPTION OF GASES. 53
into the mould and the melted substance poured in, care
being taken to prevent the formation of a hollow at the
aperture from the contraction of the substance on cooling,
by pouring over it some freshly melted substance. It
often happens that on opening the mould the ball splits
into two pieces; this is best avoided by heating the out-
side of the mould for a few moments in the flame of a
spirit lamp before opening. Infusible bodies must be
made into a paste with water and the mass pressed into
the mould containing the platinum wire; on drying they
are generally hard enough for use. The balls thus pre-
pared, however, often possess the property of absorbing
a considerable quantity of gas in their pores; when this
is the case, these bodies can only be used after having
been saturated with some liquid which does not absorb
gases, such as syrupy phosphoric acid &c. If it is re-
quired to act upon a gas with a liquid, a ball of coke
fastened upon a platinum wire is employed, and the coke
ball saturated with the absorbent. These balls are made
from a mixture of one part of bituminous coal, as free
as possible from iron pyrites, and two parts of coke. This
dry powder is placed in the mould round a platinum wire
and the whole slowly heated over a charcoal fire until the
mould is red-hot. If the mass is found to be too porous
after heating, it is easy to give it the requisite solidity
by dipping the ball, heated above 100 C., into syrup of
sugar or coal tar, and then strongly heating it in a gas
blowpipe. Before such balls can be used, they must be
well boiled in hydrochloric and nitric acids to remove
the metals and metallic sulphides which are present. In-
stead of a coke ball it is often convenient to employ
one of papier-mache made by pressing wet filtering paper
into the mould and drying at 100 C.
54 DEVELOPMENT OF A GENERAL FORMULA.
Although the volume of such balls generally does
not exceed one 'division of the absorption tube, still the
layer of atmospheric air adhering to the surface may
cause an error of from 0.05 to 0.1 division: In order to
dimmish this almost imperceptible error, it is only neces-
sary to hold the moistened ball under mercury between
the thumb, fore- and second-finger and to rub the surface
of the ball so as to allow the adhering air to escape up
the surface of the wire, which is then pushed on with
the fingers, until the ball appears above the surface of
the mercury in the absorption tube. If merely a small
point of the ball is seen at the side of the tube, it may
be directly pushed up into the gas, if, however, a bubble
of air surrounds the ball , it must be instantly withdrawn
and the operation repeated. When the ball is to be
removed from the gas, it must be rapidly drawn down
below the mercury and may then remain, until the volume
of gas has been read off. When these precautionary
measures are carried out, a ball may be taken in and
out 6 or 8 times without diminishing the volume of
the gas.
In almost all cases it is impossible to make use of
liquid absorbents, as the gases are then dissolved in
quantities depending upon their coefficients of absorption
and their relative volumes.
Having thus described the order of the processes
adopted, I proceed to develope a general formula for the
calculation of the relative volumes of the constituents of
a mixture of known gases.
Supposing that V Q volumes of the original gas was
employed for analysis, and that V l volumes remained
after the first absorption, V 2 volumes after the second
absorption, and V n volumes after the third absorption,
DEVELOPMENT OF A GENERAL FORMULA. 55
the gas must have consisted of V - - V l volumes of the
first constituent, V l V 2 of the second, and K, V n
of the third, whilst the residual volume V n was composed
of non-absorbable combustible gases. If this volume V,
contained four combustible constituents, they may in most
cases be determined by transferring a portion P of the
total volume into the combustion -eudiometer, exploding
with oxygen, and determining, according to the method
just described, the volumes of carbonic acid and watery
vapour formed , and the quantity of oxygen used.
Let the component volumes of the gas P, be #, y, z,
and 10, the volumes of carbonic acid which the units of
these components form on combustion j, 6], Ci, ?i, and
let the volumes of oxygen required for the combustion of
the units of the same components, or the contraction
which ensues on the combustion, be ._,. l>.,. c. 2 . d?, and the
volume of aqueous vapour which is formed from the units
of each component t/ 3 , 6 3 , f 3 , <4- And let. also, the total
amount of carbonic acid produced by explosion of the
volume of gas PbeP^ and the volume of oxygen required
for this combustion P 2 , and, lastly, let the amount of
aqueous vapour formed by explosion from P volumes of
gas be P 3 , the values of x , y , z , and w are then found
from the following equations in which the values of a, b.
c. d are to be made equal to 1.
56 GENERAL FORMULA.
p = a X+b Y+cZ+d W
P l = a,X + ^ Y J r c l Z-}-d l W
P 2 = a 2 X-\-b 2 Y+e 2 Z+dv W
P 3 = 8 x 4- 6 3 y 4- c 3 z 4- 4 w
X =(PA + PiA, + P 2 A 2 + P 3 A 3 )
Y = (PB + P.B, + P 2 B 2 + P 3 B 3 )
Z = (PC+ P& + P 2 C 2 + P 3 C 3 )
W = (PD + P 1 A + P-2 A + A A)
A =
A l = b 2 (c 3 d c c? 3 ) -f- 6 3 (c c7 2
^4 2 = b B (c d 1 c l d)-\-b (ci^ 3
A B = b fadt ctdj + b! (c 2 d c d 2 ) +b. 2 (c di
B = c'! (d 2 3 4 a 2 ) -f-
j&! = c 2 (d 3 a d
# 2 = c 3 (cZ c/! d l a)- J r c (d 1 a s 4i) + c i (4 d a- 3 )
B 3 = c (d 1 a 2 d 2 ai) -f- GI (d 2 a d a 2 ) -\- c 2 (d ^ d l a )
C = d l ( 2 b 3 a 3 b 2 ) + 4j (a ^i i &s) + ^3 (i ^2 2 ^i )
Ci == d 2 (3 b a b 3 ) -)- d 3 (a b 2 a 2 b)-\-d (a 2 b 3 3 b 2 )
C 2 = d 3 (a b l a l b)-}-d (a l b 3 a 3 b 1 )-^-d 1 (a 3 b a b 3 )
C 3 = d (ci}b 2 a 2 bi)-{-d l (a 2 b a b 2 )-\-d 2 (a b a^b )
D = ! (b 2 c 3 b 3 c 2 ) -\- a 2 (b 3 c l b^ c 3 ) -)- a 3 (^ c 2 b 2 c l )
D l = a 2 (b 3 c b c 3 )-f-3(^ C 2 b 2 c)-\-a (b 2 c 3 b 3 G 2 )
D 2 = a 3 (b c l 61 c ) -f- a (^ c 3 b 3 c t ) -|- i (^3 G b c 3 )
D = a 6 c b C -- ^2 ^ <? 2 ^ C 6 c
-f- a 2 ^4 2 -
bB + ^ B, + b, B 2 + b 3 B 3
cC -f c x Q 4- c 2 C 2 4-
+ ^ A + d 2 A 4-
GENERAL FORMULA. 57
or when only three gases are to be determined:
P = a X+b Y+c Z
P l = a 1 X+b 1 Y
X = - (PA
Y (PB
Z =
A = V-2
AI = b. 2 c - - b c 2
A 2 = b <?! biC
B = c l a 2 6*2^!
BI = c^a c a^
B 2 = C j - Cj
C = aib 2 a 2 bi
Ci = a 2 b - - a b 2
C% = a bi j6
z/ = a A -f- j A l -\- 2 A 2
= bJ3 + &i-#i +b. 2 & 2
= C C -f- 0'! 6\ -)- C 2 C" 2
or, lastly, for a mixture of two gases:
p =a X+b Y
P l =
X =-j(Pb l --P 1 b)
Y =(P l a --Pa,)
58 SPECIAL DETERMINATIONS.
When the volume of gas P contains a fifth consistent
non - combustible and non - absorbable gas, as for instance
nitrogen, it is easy to determine its amount by deducting
the volume of the superfluous oxygen from the residual
gas after determination of the other constituents. This
is best done by exploding the residual gas with a known
volume of hydrogen large enough to burn all the oxygen.
If the sample P of the gas volume V n was thus found
to contain x y z w n volumes of the five gases, the follow-
ing simple proportion gives the volumes contained in V n \
V ^ y__H 7 _ Vn U,'_Zs. N^'
which, together with the constituents determined by ab-
sorption F - - F! , Fj - - F 2 , F! - - V n , compose the ori-
ginal volume F .
After these general considerations we proceed to the
special determination of each gas.
1. NITROGEN.
Nitrogen can easily be made to combine with oxy-
gen to form nitric acid by exploding both gases with
double their volume of a mixture of two volumes of
hydrogen, and one of oxygen. If this detonating gas
amounts to from three to five times the volume of the
original gases, the quantity of nitric acid produced is so
considerable that the mercury which is in contact with
the gas, is dissolved with evolution of nitric oxide, and
on drying the gas , crystals of subnitrate of mercury are
found to be deposited on the sides of the eudiometer.
It is, however, not possible to obtain exact results with
such a combustion, as the decomposition is never com-
NITROGEN.
59
plete, and the tension of the vapour of nitric acid as
well as the quantity of nitric oxide formed from the de-
composition of the nitric acid, prevent the attainment of
any accurate measurements. The following experiments
made with mixtures of the electrolytic detonating gas and
atmospheric air, show the limits within which the nitro-
gen combines with the oxygen to form nitric acid.
Vol.
Pres-
sure.
Temp.
c.
Vol. at
C. and
l m press.
Air employed
275.2
0.4779
17.5
123.62
-{- detonating gas
No explosion ... ...
298.3
298.3
0.5006
0500G
17.7
17.7
140.24
140 24
319.0
0.5210
17.7
156.09
\iter explosion .... .
274.7
0.4784
17.2
123 64
-4 detonating gas .
331.1
0.5344
17 2
166.47
Alter explosion
272.1
0.4821
16.3
12380
-{- detonating gas ...
341.G
0.5521
16.3
177.67
Alter explosion . . .
272.1
0.4824
16.7
123.70
Air employed
278.6
0.4895
16.7
128.52
+ detonating gas
3G1.0
0.5711
16.9
194.22
Alter explosion . . . .
278.6
0.4896
16.9
128.50
+ detonating gas
379.8
0.5912
173
211.17
\iter explosion
278.0
0.4899
16.6
128.40
Air employed
-\- detonating gas
285.9
409.7
0.4985
0.6225
16.4
16.7
134.45
240.35
Alter explosion .
285.2
0.4976
16.8
133 70
-{- detonating gas
Alter explosion
435.2
281.0
0.6488
0.4921
16.8
16.7
266.00
130.32
\ir employed
169.1
0.4407
6.3
72.84
-{- detonating gas
After exolosion .
378.5
153.4
0.6483
0.4342
6.7
6.5
239.51
65.06
GO SPECIAL DETERMINATIONS.
Hence 100 volumes of air with
13.45 volumes of detonating gas did not explode.
100 volumes of air with
26.26 detonating gas when exploded left 100.02 residual air
34.66 100.15 &-
43.72 100.07
51.12 . 99.98
64.31 99.90
78.76 99.43
97.84 96.92
226.04 88.56
The irregularities and inaccuracies which occur in
almost all the older eudiometric results, arise chiefly
from the fact that in the explosions this formation of
nitric acid was not guarded against. The error is easily
avoided, as is seen from the above experiment, by never
adding more than from 26 to 64 volumes of combustible
gas for every 100 volumes of non- combustible gases.
In order to see if a gas consists of pure nitrogen or
whether in addition it also contains oxygen, or a com-
bustible gas, the following process is employed. First
of .all we determine whether the gas is combustible, by
passing an electric spark through a measured volume of
the gas itself. If no ignition takes place, we may conclude
that no large quantity of combustible gas is mixed with
oxygen and nitrogen. About 40 volumes of electrolytic
detonating gas is next added to every 100 volumes of the
original gas, and the mixture exploded. If the original
volume is not altered after this explosion, we may be
certain that oxygen and combustible gases are not present
together in the mixture. In order to determine whether
oxygen, and not a combustible gas, is present, so much
hydrogen and detonating gas is added that the volume
NITROGEN. Gl
of the original gas plus hydrogen is to the detonating
gas again in the ratio of 100 to 40. If after the explosion
the volume is found to be equal to the original gas plus
the hydrogen added, oxygen cannot be present, and we
only have now to determine whether or not a trace of a
combustible gas is contained in the original gaseous
mixture. This is done by exploding with excess of at-
mospheric air, added in such a quantity that the volume
of the detonating gas, formed by the hydrogen added,
and the oxygen of the air, amounts to from 26 to 64
per cent of the residual incombustible gases. If 2 / 3 of
the volume of gas, which has disappeared by the explosion,
is exactly equal to the volume of hydrogen added, we
may be sure that the gas under examination consisted
of pure nitrogen.
As the volumes of gas in the eudiometer are almost
always read off under various pressures, and as the
relation between the volumes of combustible and non-
combustible gases is determined for equal pressures, a
long calculation would each time be necessary in order to
find the required volume of detonating gas. This trouble-
some operation is avoided by once for all determining
the various depths to which the mercury is depressed by
admission of equal volumes of air into the eudiometer.
These observations are thrown together into a table, in
which the barometric pressure, and the small variation
in the level of the mercury in the trough is not con-
sidered. By the successive addition of equal volumes of
air for instance the following results were obtained.
G2 SPECIAL DETERMINATIONS.
Difference
The 1st measure agreed with division 100
1. 2nd 123
.,
145 21
11 4th 166 2()
11 5th 186 lg
6th 204
7fli 991
I? ' tu it 11 11 11 ""*- -I p
8th 237
9th 253
" 1 A
11 10th 267
By help of such a table, the required volume of de-
tonating gas can be easily found. Suppose, for instance,
that we had to add so much to a volume of gas reaching
to division 190, that the original and added volumes
should be in the proportion of 100 to 30. The nearest
number to 190 which we find in the foregoing table, is
186 representing 5 volumes; 18 divisions are equal to
one volume in this part of the tube and hence the 4 di-
visions required to make up 190. are equal to 0.22 vol.
The volume 190, therefore, represents a volume of gas
5 -f- 0.22 = 5.22 reduced to the atmospheric pressure,
and as 100 : 30 : 5.22 : 1.57 we have to add 1.57 volumes
of detonating gas in order to have the required amount.
The total volume after addition of the detonating gas
must be 5.22 -f- 1.57 = 6.79. Hence the division, which
corresponds to this 6.79 measures, is 217.4 and the
detonating gas is to be added until the level of the
mercury sinks to this division.
The detonating gas as used for gasometric purposes
is prepared by electrolysis, and plays a most important
and essential part in the processes of gas analysis. The
NITROGEN. . G3
small apparatus Fig. 34 is employed for the preparation
of this gas.
The small platinum plates aa which dip into a
liquid composed of one volume of pure monohydrated
Fig. 34.
sulphuric acid to 10 of water , are welded on to the pla-
tinum wires bb. These wires are placed in connection
with the poles of four common sized zinc -carbon ele-
ments, and thus a regular current of gas is evolved
which may he instantly stopped hy breaking contact. It
is adviseable to surround the decomposing cell by a glass
cylinder containing some non-conducting liquid which
does not easily freeze, by means of the arrangement
G4
SPECIAL DETERMINATIONS.
represented in the wood-cut. The wires and acid are kept
cool by the surrounding liquid and the requisite height
given to the delivery tube e which is ground into the
neck of the decomposing cell and the joint rendered air-
tight by a layer of water. The volume of this tube, and
of the bulbs containing a little strong sulphuric acid , is
only a few cubic centimetres, so that by allowing the
evolution to continue for 5 minutes the whole of the
atmospheric air is completely removed. Irregularities in
the composition of the detonating gas from the pro-
duction of the higher oxides of hydrogen cannot occur
with this instrument, since the formation of peroxide of
hydrogen takes place only 1 at the beginning of the evo-
lution and ceases as soon as the electrolyte has dissolved
a certain amount of this substance. When exploded with
other non - combustible gases, the electrolytic detonating
gas disappears completely without leaving any residue
of either oxygen or hydrogen, as may be seen from the
following experiments conducted under extremely varying
circumstances.
.'-
Vol.
Pres-
sure.*
Temp.
C.
Vol. at
0C. and
l m press.
Original air in which the detonating
gas had been once exploded .
225.8
0.5107
G.4
112.G8
After addition of detonating gas
295.9
0.5806
G.4
1G7.87
After explosion
225 5
05110
6 2
112 67
The same 24 hours later ; . .
224.8
0.5112
5.7
112.61
After a second addition of de-
314.0
0.5977
5.7
183.84
After exDlosion .
224.4
0.5125
5.7
112.65
* In these and all the following data for pressure the correction
for the tension of aqueous vapour and for the difference of
NITROGEN.
65
Original volume of air 112.68
After first combustion with 55.19 detonating gas 112.68
Measured again after 24 hours 112.57
After a second combustion with 71.23 detonating gas 112.66
As an example of a nitrogen determination made
with electrolytic detonating gas I cite the analysis of the
gas from a spring in the small group of geysirs near
Maelifell in the north of Iceland, which is free from car-
bonic acid and contains only traces of hydrogen.
Vol.
Pres-
sure,
Temp.
C.
Vol. at
C. and
l m press.
Original firas ... ...
185.0
03948
16.0
69.00
229 8
4380
16 1
95 05
After the explosion
186.4
0.3934
16.4
69.18
I hydrogen
277 3
4838
16 3
126 61
-j- detonating eras ....
360.3
0^5617
16.4
190.92
After the explosion
277.2
0.4837
16.4
126.47
+ air
525.7
0.7301
15.8
362.84
After the explosion ....
447. G
0.6529
16.2
275.88
Gas before the combustion
Gas after the combustion with detonating gas
Gas and hydrogen before the combustion . .
Gas and hydrogen after the combustion with de-
tonating gas . ,
Hydrogen added ,
Hydrogen found by combustion with air . . .
69.00
69.18
126.61
126.50
57.61
57.97
height between the mercury in the eudiometer and in the
trough is already made. The numbers in the first column
likewise represent the volumes, corrected for the error of the
meniscus , as taken from the capacity table of the eudiometer.
5
GG SPECIAL DETERMINATIONS.
The gas under examination consists therefore of
nitrogen with a trace of hydrogen ; viz
Nitrogen . . . 99.48
Hydrogen . . . 0.52
100.00
2. OXYGEN.
Oxygen when present alone or when mixed with
nitrogen, is best determined by explosion with excess of
hydrogen. .As~*/ 3 of the volume of gas undergoing com-
bustion consists of hydrogen and l / z - of oxygen, the re-
quired volume of oxygen is found by dividing the de-
crease of volume ensuing from the explosion by 3. The
hydrogen required for the combustion is evolved in a
small flask from pure zinc and dilute sulphuric acid, and
it is freed from all traces of carbonic acid , sulphuretted
hydrogen, and sulphuric acid mechanically carried over,
by passing through a small delivery tube containing
pieces of hydrate of potash. When the evolution has
proceeded for 5 or 10 minutes, we may assume that all
the air has been displaced from the liquids and the small
spaces in the apparatus. When the greatest amount of
accuracy is required, it is preferable to evolve the hy-
drogen by electrolysis. For this purpose the small ap-
paratus Fig. 35 may be used. The decomposing cell
contains pure sulphuric acid diluted with 10 times its
weight of water, and the positive pole consists of a pla-
tinum wire a melted through the glass placed in contact
with mercury amalgamated with zinc 6, whilst the ne-
gative pole c is composed of a platinum plate. If the
current from two or three carbon -zinc elements is led
through the apparatus in the direction indicated by the
OXYGEN. G7
arrows, pure inodourous hydrogen is evolved in a con-
stant stream, and after being washed by the small
quantity of sulphuric acid contained in the bulbs <7, the
Fig. 35.
gas may be collected for analytical purposes. As the
surface of the zinc -amalgam very soon becomes covered
with a layer of saturated solution of sulphate of zinc, the
liquid must often be removed, generally after each ope-
ration. This is accomplished by removing the glass
stopper fitting into the tube A, and also the delivery
tube ground in at i, and pouring the new solution into
the vessel through the small reservoir n which serves
during the evolution as a water joint; the saturated
solution thus flows out from the tube A, and is replaced
by fresh acid. This arrangement is best contained in a
G8 SPECIAL DETERMINATIONS.
glass cylinder filled with alcohol to prevent the heating
of the platinum wires during the passage of the current.
If the gas under examination is known to consist
almost entirely of pure oxygen , or if this has been as-
certained by preliminary experiment, from three to ten
times its volume of hydrogen can be added for explosion.
When a greater amount of hydrogen is added, the in-
flamability of the mixture is destroyed, or, what is more
to be feared, considerably diminished. If, on the other
hand, the gas contains only a small amount of oxygen,
it is mixed with double its volume of hydrogen, and if
the mixture is not inflamable, so much detonating gas is
added that a perfect explosion takes place. In every
case care must be taken to mix the gases completely,
before ignition, in the manner described.
In order to be satisfied that the combustion has not
occured near the limits of the inflamability of the mixture,
the experiment must be repeated with addition of rather
a larger quantity of detonating gas. If the two expe-
riments do not agree, it is to be supposed that the last
result with the greater amount of explosive gas is the
more accurate. With a little practice, however, it is easy
to tell from the force of the explosion, whether the re-
lation between the combustible and non-combustible gases
was such that a complete combination could occur.
The amount of oxygen contained in the atmosphere
may be determined according to this method with the
greatest accuracy, when a very carefully calibrated eudio-
meter is employed, l m long and about 0.025 wide, and
the observations are conducted in a space within which
the changes of temperature are small and as gradual as
possible.
OXYGEN. G9
The air for these determinations is collected in
small flasks of about 14 ounces capacity whose necks
have been previously elongated before the blowpipe.
Inside the flask a small piece of fused chloride of cal-
cium is placed for the purpose of absorbing the ammonia,
and a similar piece of fused potash to absorb the car-
bonic acid is also introduced, and both substances are
allowed to crystallize on the sides of the glass by ad-
dition of a drop of water. It is quite requisite to remove
the carbonic acid of the air previous to analysis , for if
the quantity of this gas present amounts only to 0.05
per cent of the total volume still this quantity would
produce an appreciable error in the oxygen determination,
as carbonic acid when exploded with excess of hydrogen
in presence of the detonating gas is decomposed into an
equal volume of carbonic oxide, an equal volume of
hydrogen disappearing, so that the volume of combined
gas would be 0.05 per cent too large.
The eudiometers used for analysis of air are so
long that when placed in a vertical position a vacuum is
formed at their upper end; hence on admission of air,
the mercury is apt to be carried with great violence
against the head of the tube which is thus often broken.
On admitting air , the end of the eudiometer must there-
fore be so lowered that no vacuous space is formed above
the mercury. In order to fill a large tube with mercury,
it is most convenient to lay the tube in a groove, a a,
Fig. 36 (see p. 70), slanting at about an angle of 30,
and to allow the mercury to flow from the funnel J,
furnished with a stop -cock, through a long tube into the
lowest part of the eudiometer. All increase of tempe-
rature of the mercury by handling must as much as
possible be avoided. The air is always measured saturated
70
SPECIAL DETERMINATIONS.
with the maximum amount of aqueous vapour. For this
purpose a drop of water , whose volume is inappreciable
compared to the total capacity of the tube, is brought
Fig. 36.
into the head of the eudiometer before filling -in the
mercury, so that on admission of air, the drop moistens
the whole length of the tube containing gas. If the
moisture remains at one spot only of the eudiometer, the
aqueous vapour would not adjust itself quickly enough
throughout the mass of the gas to correspond to the
alterations of temperature, and hence a slight error
would be introduced.
It is, lastly, necessary to subtract the volume of the
water formed by the combustion from the volume of gas
which has disappeared. This correction is made by mul-
tiplying the volume of gas which has disappeared, reduced
to l m pressure and C., by 0.0007, and subtracting the
product thus obtained from the observed contraction.
In order to show the great accuracy of this method,
I cite the following series of analyses of atmospheric air
from the court of the Marburg laboratory , which I made
in January and February 1846, more for the sake of
testing the exactitude of the method, than for determining
the composition of the air.
ANALYSES OF AIR.
71
ANALYSES OF AIR
in January and beginning of February 1846.
l. SERIES.
9th January. Temperature of the air Max. 14 C. Min. 025 C.
Barometer 0.7648.
Vol.
Pres-
sure
at 0.
Temp.
C.
Vol. at
C. and
l m press.
Air e
Alter
Alter
tnployed . . . . f . .
841.8
1051.7
878.8
parts
0.5101
0.7137
0.5469
0.3
0.3
0.3
428.93
749.77
480.09
addition of hydrogen . .
the explosion
Air in 100
Nitrogen . . . 79.030
Oxygen . . . 20.970
100.000
Air employed ....
Alter addition of hydrogen
After the explosion . .
859.3
1051.9
870.3
0.5225
0.7079
0.5317
0.6
0.6
0.6
448.00
743.01
461.72
Air in 100 parts
Nitrogen . . . 79.037
Oxygen . . . 20.963
100.000
llth January. Max. temp, of air 088 C. Min. 26 C. Bar. 0.7562.
Air employed ....
After addition of hydrogen
After the explosion . .
885.4
1052.7
858.3
0.5388
0.7031
0.5136
0.5
0.5
*0.5
476.20
738.82
440.03
Air in 100 parts
Nitrogen ... 79.073
Oxygen . . . 20.927
100.000
72 SPECIAL DETERMINATIONS.
13th January. Max. temp, of air 15 C. Min. 25 G. Bar. 0.7423.
Vol.
Pres-
sure
Temp.
p
Vol. at
0C. and
at 0.
l m press.
Air employed ' >'
882.2
527G
9
464 94
After addition of hydrogen . .
1053.8
O.G929
0.8
729.38
After the explosion
8G1.8
0.5084
0.7
437.83
Air in 100 parts
Nitrogen . . . 79.086
Oxygen . . . 20.914
14th January.
Air employed
After addition
After the explosion
Air in 100 parts
Nitrogen . . . 79.050
Oxygen . . . 20.950
100.000
SERIES 2.,
A different eudiometer used in these determinations.
18th January. Max. temp, of air 14 C. Min. C. Bar. 0.7397.
100.000
Max. temp, of air 24 C. Min. 49 C. Bar. 0.7477.
870.3
0.5213
0.3
453.20
of hydrogen
1045.0
0.6914
0.3
721.71
osion '. . .- .. u -
858.0
0.5099
0.2
437.01
Air employed . . . . ,
After addition of hydrogen
After the explosion . .
831.6
994.7
808.0
Air in 100 parts
0.5272
0.6836
0.5015
0.9
0.9
0.9
436.97
677.74
403.88
Nitrogen
Oxygen .
79.094
20.906
100.000
845.3
1004.6
809.4
Air employed
After addition --of hydrogen
After the explosion ....
Air in 100 parts
Nitrogen . . . 79.072
Oxygen . . . 20.928
100.000
0.5380
0.6917
0.5057
1.2
1.4
1.4
452.78
691.36
407.24
ANALYSES OF AIR. 73
20th January. Max. temp, of air 6 C. Min. 25 C. Bar. 0.7402.
Vol.
Pres-
sure.
Temp.
C.
Vol. at
C. and
l m press.
Air employ 6<i .
809.G
0.5001
1.7
402.39
After addition of hydrogen . .
991.0
0.6751
1.8
664.64
After the explosion
823.9
0.5041
2.1
412.16
Air in 100 parts
Nitrogen . . . 79.073
Oxygen .... 20.927
100.000
Air employed ...
833.5
0.5170
2.7
426.74
Alter addition of hydrogen . .
997.1
0.6744
3.0
665.19
811.8
0.4949
3.0
397.42
Air in 100
parts
Nitrogen . . . 79.073
Oxygen . . . 20.927
100.000
22nd January. Max. temp, of air 109 C. Min. 56 C. Bar. 0.7339.
Air employed
839.0
0.5236
3.4
433.92
Alter addition of hydrogen . .
991.3
0.6707
3.6
656.20
After the explosion
801. G
0.4854
3.6
384.03
Air in 100 parts
Nitrogen . . . 79.081
Oxygen . . . 20.919
100.000
\ir employed
851.4
0.5374
4.0
450.96
After addition of hydrogen . .
992.1
0.6725
4.2
657.06
Alter the exolosion
793.2
0.4797
4.2
374.73
Air in 100 parts
Nitrogen ... 79.120
Oxygen .... 20.880
100.000
74 SPECIAL DETERMINATIONS.
24th January. Max. temp, of air 10 C. Min. 5 C. Bar. 0.7384.
Vol.
Pres-
Temp.
Vol. at
C. and
sure.
C.
l m press.
Air employed ; ./ -
855.2
0.5448
3.4
460.21
After addition of hydrogen . .
1004.7
0.6850
3.4
679.52
After the explosion
80G.O
0.4913
3.6
390.83
Air in 100 parts
Nitrogen . . . 79.079
Oxygen . . . 20.921
Air employed
After additior
After the explosion
100.000
860.0
0.5382
5.2
454.22
f hydrogen . .
1004.6
0.6769
5.4
665.34
ion . . -. :< '1 ; f . -
805.0
0.4833
5.3
381.65
Air iii 100 parts
Nitrogen . . . 79.057
Oxygen . . . 20.943
100.000
26th January. Max. temp, of air 9 C
OC. M
842.2
1002.5
811.2
in. 85 C
0.5274
0.6825
0.4994
/. Bar.
5.6
5.7
5.5
0.7334.
435.35
670.26
397.13
After addition of hydrogen ...
After the explosion
Air in 100 parts
Nitrogen .'- . . . fi 79.073
Oxygen . . . 20.927
Air employed
After additior
Alter the explosion
100.
868.5
1007.8
799.7
000
0.5613
0.6930
0.4909
5.1
5.1
5.2
478.59
685.65
385.25
' hydrogen . .
ion
Air in 100 parts
Nitrogen . . ." 79.066
Oxygen . .. . .- 20.934
100.000
ANALYSES OF AIR. 75
jsth January. Max. temp, of air 50 C. Min. 18 C. Bar. 0.7402.
Vol.
Pres-
sure.
Temp.
C.
Vol. at
0C. and
l m press.
Air employed
841.1
0.5317
5.4
438.58
Alter addition of hydrogen . .
After the explosion
992.7
800.G
0.6771
0.4889
5.4
5.3
G59.17
383.97
Air employed
After addition
After the expl
30th January
Air employed
Alter addition
After the expl
Air employed
Alter addition
After the expl
Air in 100
Nitrogen . .
Oxygen .- .-
parts
79.072
. 20.928
.4 458.61
.5 679.55
.5 392.00
Jar. 0.7457.
.0 455.41
.0 689.77
.0 403.73
.4 458.05
.4 685.75
.2 398.82
100.000
854.3 0.5474 5
1003.2 0.6911 5
802.8 0.4981 5
parts
. 79.089
. 20.911
of hydrogen . .
Air in 100
Nitrogen . .
Oxygen . .
Max. temp, of air 7
100.000
8 C. Min. 38 C. 1
851.2 0.5468 6
1010.1 0.6979 G
81G.9 0.5051 6
parts
. 79.111
20.889
of hydrogen . .
osion .....
Air in 100
Nitrogen . .
Oxygen . .
100.000
856.2 0.5475 6
1010.5 0.6945 G
811.2 0.5028 G
parts
. 79.108
20.892
of hydrogen . .
Air in IOC
Nitrogen . .
Oxygen . .
100.000
76 SPECIAL DETERMINATIONS.
1st February. Max. temp, of air 98 C. Min. 51 C. Bar. 0.7382.
Vol.
Pres-
sure.
Temp.
C.
Vol. at
0C. and
l m press.
Air employed .'* 862.1 0.5512 6.3 464.51
After addition of hydrogen . . 1005.1 0.6866 6.3 674.59
After the explosion 801.2 0.4906 6.2 384.34
Air in 100 parts
Nitrogen ... 79.160
Oxygen . . . 20.840
100.000
Air employed t: V^} -':.U'V. ".', ' 854.9 0.5520 5.9 461.97
After addition of hydrogen . . 1003.9 0.6940 6.0 681.78
After the explosion . . >> v .. . 805.5 0.4980 5.9 392.69
Air in 100 parts
Nitrogen . . . 79.141
Oxygen .- . . . 20.859
100.000
3rd February. Max. temp, of air 65 C. Min. 12 C. Bar. 0.7458.
Air employed U^:.>v.!V . . 850.7 0.5467 6.2 454.75
After addition of hydrogen . . 1010.8 0.7001 6.2 691.95
After the explosion . ... .r '. ' . 812.7 0.5115 6.1 406.63
Air in 100 parts
Nitrogen . . . 79.075
Oxygen . . . 20.925
100.000
Air employed . |p <.;,*, i.-.. ; 863.7 0.5576 5.5 472.11
After addition of hydrogen . . 1006.7 0.6911 5.5 682.02
After the explosion 800.7 0.4914 5.6 385.60
Air in 100 parts
Nitrogen . . . 79.060
Oxygen . ., . 20.940
100.000
ANALYSES OF AIR. 77
5th February. Max. temp, of air 38 C. Min. 012 C. Bar. 0.7428.
Vol.
Pres-
sure.
Temp.
C.
Vol. at
C. and
l m press.
Air employed
848.5
0.5425
5.5
451.24
After addition of hydrogen , .
After the explosion
1003.4
80G.2
O.G919
0.5025
5.5
5.4
680.57
397.29
Air in 100 parts
Nitrogen . . . 79.063
Oxygen .... 20.937
100.000
Air employed
858.0
0.5500
5.4
462.78
After
addition
of hydrogen . .
1002.7
0.6867
5.6
674.72
After
the explosion
798.G
0.4893
5.6
383.99
Air in 1QO parts
Nitrogen . . . 79.048
Oxygen . . . 20.952
100.000
8th
February.
Max
. temp, of air 61 C. Min. 15 C. Bar. 0.7441.
Air employed
849.8
0.5460
5.1
455.52
9IU|TWJ ^v-
After addition
of hy<
Irogen . .
1006.0
0.6958
5.0
687.33
After
the explosion
807.5
0.5053
4.7
401.13
Air in 100 parts
Nitrogen . . . 79.047
Oxygen .... 20.953
100.000
In normal determinations of the composition of the
air a still greater degree of precision may be attained,
by repeating the observation of the height of the mercury
several times at regular intervals. From the agreement
between the reduced volumes read off, the point in the
series of observations is found, at which the temperature
78
SPECIAL DETERMINATIONS.
has been most constant. As an example of such a de-
termination, I may give an analysis of air, also collected
from the court of the Marburg laboratory, for the ana-
lysis of which a somewhat smaller eudiometer was
employed.
-
Vol.
Pres-
sure.
Temp.
C.
Vol. at C.
and l m pres-
sure.
GhO'
754.9
0.5045
15.4
3G0.52
Air employed . . .
7hO'
755.0
0.504G
15.4
3GO.G3
360.62
8hO'
755.2
0.5047
15.5
360.70
jllhO'
After addition of /I9h0'
hydrogen . j
( IhO'
904.0
904.G
904.9
0.6520
O.G521
O.G518
15.8
1G.O
1G.O
557.20
557.24
557.17
> 557.20
3hO'
732.3
0.4781
1G.1
330.G4
After the explosion
4h()'
732.5
0.4777
1G.1
330.45
330.54
5M>'
732.7
0.4777
10. 1
330.54
[;
Nitrogen
Oxygen .
79.036
20.964
100.0UO
Should an alteration of temperature take place
during the observations, a reduction of the mercury in
the eudiometer and barometer to the same density by
means of table IV must not be omitted.
When oxygen occurs mixed with combustible gases
it is most convenient to determine it by absorption. A
ball of phosphorus cast under warm water may be used
for this purpose. The absorption only occurs at tem-
peratures above 10 or 12, indeed sometimes not until
the temperature has risen to 15 or 20. If oxygen is
OXYGEN. 79
present in large quantities, or if the gas contains sethyl,
methyl, elayl, or other similar hydrocarbons, the phos-
phorus may often be heated almost up to it melting
point without the slow combustion beginning. It is,
therefore, necessary to observe at the commencement of
the experiment, whether the ball is surrounded by a
white cloud of phosphorous acid. If this be the case,
the absorption of the oxygen takes place completely, but
from the absence of such a cloud we cannot infer that
oxygen is not contained in the gas.
The tension of the vapour of the phosphorous acid
which coats the walls of the absorption tube, is con-
siderable, and would introduce a large error into the
analysis, were the gas not most carefully dried with a
ball of potash, before the volume is read off. This is,
however, attended with some difficulty, as the phosphorous
acid is very hygroscopic. It is, on the whole, far better
to adop.t Liebig's suggestion for the determination of
oxygen, and to employ, instead of the phosphorus, a
ball of papiermache saturated with a concentrated so-
lution of pyrogallate of potash. The absorption occurs
generally slowly, but in the end completely, particularly
if the ball be once renewed. After this absorption the
gas must also be dried by a ball of potash containing as
little water as possible. If other gases are present which
are absorbed by potash, their amount must be deter-
mined before the ball of pyrogallate of potash is intro-
duced. The syrupy solution of the potash salt used for
the absorption does not require to be chemically pure.
The rough product obtained from the destructive de-
stillation of Chinese galls when concentrated in the water-
bath, and saturated with potash, answers this purpose
extremely well.
80 SPECIAL DETERMINATIONS.
An analysis of atmospheric air made with pyrogallate
of potash gave the following results.
Vol.
Pres-
sure.
Temp.
C.
Vol. at
C. and
l m press.
3G8.9
0.5759
3.1
210.08
After absorption of the oxygen .
313.8
0.5358
3.1
1GG.25
Nitrogen
Oxygen .
Found. Actual composition.
79.14 7-9.04
20.8G 20.9G
100.00
100.00
3. CARBONIC ACID.
When pure carbonic acid is required in gasometric
research, it can in no case be prepared by the action of
nitric or hydrochloric acids on a carbonate, as traces of
these volatile acids might pass over with the carbonic
acid, and render the gas under examination impure. A
perfectly chemically pure product is obtained by pouring
concentrated sulphuric acid over chalk, and adding a few
drops of water. The gas is in this way evolved in a re-
gular stream lasting for a long time, owing to the
gradual decrepitation of the chalk under the liquid,
whilst the gypsum formed effects no irregularity in the
production of the carbonic acid, as is the case, when dilute
sulphuric acid is employed. Carbonic acid is determined
by absorption with a potash -ball attached to a platinum
wire. The ball of caustic alkali must contain so much
water that it is soft enough to receive an impression from
CARBONIC ACID. 81
the nail, and must be moistened externally with water
before admission to the gas.
If very large quantities of carbonic acid have to be
absorbed, the ball must after some time be withdrawn
from the gas, and again introduced, after the hard crust
of carbonate has been completely washed off. When
particularly accurate results are required, it is best to
bring a second potash ball containing as little water as
possible into the gas, in order to ensure perfect absence
of aqueous vapour ; this precaution should always be
attended to when the sides of the eudiometer have been
moistened more than was necessary. Even in this case,
however, the error incurred is not very considerable.
The following is an analysis of the carbonic acid
evolved from the large well of the mineral springs at
Nauheim, near Frankfort am Maine.
Vol.
Pres-
sure.
Temp.
C.
Vol. at
0C. and
l m press.
Air in absorption tube ....
20.1
0.524
10.1
10.16
After admission of carbonic acid
530.0
0.745
10.2
165.19
After absorption with potash . .
20.4
0.5164
10.2
10.16
It is thus seen that the carbonic acid from the
springs at Nauheim is perfectly pure.
If an analysis has to be made of a gas containing
oxygen and nitrogen, as well as carbonic acid, the amount
of this latter gas is first determined in an absorption
tube, and the residual mixture of gases then transferred
into the combustion -eudiometer, in order to explode the
gases with hydrogen in a tube- whose sides are free from
6
82
SPECIAL DETERMINATIONS.
potash, which alters the amount of the tension of aqueous
vapour allowed for, when the gas is measured moist.
If the analysis can only be made in one and the
same eudiometer, the oxygen may be absorbed by pyro-
galate of potash after the determination of the carbonic
acid; in this case it is, however, necessary to dry the gas
completely before observing the residual volume of
nitrogen.
I select as an example of this last process an ana-
lysis of choke-damp from the mines of lignite at Ha-
bichtswald near Cassel. Under the term .choke-damp,
are classed all those non-explosive gases, poor in oxygen
and containing carbonic acid, which often collect in the
adits and workings driven through the coal-beds and
render the working of the mines extremely dangerous
if air-shafts or other means of ventilation are not
employed.
The gas used for analysis was collected by the di-
rector of the mine, from a side level in a situation in
which it would have been dangerous to remain for any
length of time.
Vol.
Pres-
sure.
Temp.
Vol. at
C. and
l m press.
Original o-as .... . .
171.2
0.6240
13 5
101.66
After absorption of carbonic acid
1G7.3
O.G196
13.5
98.78
After absorption of oxygen . .
147.0
0.6058
13.9
84.75
Nitrogen . .
Oxygen . . .
Carbonic acid .
83.37
13.80
2.83
100.00
SULPHURETTED - HYDROGEN.
83
As the volume of free oxygen in the gas, together
with that contained in the carbonic acid, stands in a less
proportion to the nitrogen, than the atmospheric oxygen
to the atmospheric nitrogen, it may be concluded, that
in the formation of such gaseous mixtures only a part of
the oxygen is converted into carbonic acid, a part re-
maining combined in the products of decomposition of
the coal. A quantity of moist lignite was left for se-
veral weeks at a common temperature in contact with
a large volume of air, which gave the following com-
position very similar to that just examined.
Vol.
Pres-
sure.
Temp.
C.
Vol. at
C. and
l m press.
Original gas
124.0
0.5043
16.5
58.97
After absorption of carbonic acid
114.3
0.5052
1G.5
54.58
Alter absorption of oxygen . .
106.5
0.4838
17.5
48.56
Nitrogen . . .
Oxygen . . .
Carbonic acid .
82.35
10.21
7.44
100.00
4. SULPHURETTED-HYDROGEN.
The means usually employed for the separation of
sulphuretted -hydrogen from other gases are inapplicable
to exact gasometric researches. A ball of coke coated
with a solution of sulphate of copper, lactate of silver,
tartar -emetic or other metallic salt decomposeable by
sulphuretted -hydrogen, is soon covered with a layer of
sulphide, which renders further action on the gas im-
84 SPECIAL DETERMINATIONS.
possible. The result is not more satisfactory when a
moistened crystal, or a piece of the solid salt is used.
Chromate of mercury, or sulphate of copper, when used
in the form of moderately sized balls , do not absorb
more than about 9 divisions in 12 hours. Dry binoxide of
manganese, or peroxide of lead, decompose sulphuretted-
hydrogen quickly and completely, but these substances
evince, on account of their porosity, so great a power
of absorbing gases, that the diminution of volume is
always found to be more than that corresponding to the
amount of sulphuretted -hydrogen present. This error
may, however, be completely avoided in the following
manner. Pure binoxide of manganese brought into a
state of very fine division, is moistened with distilled
water to a thin paste, and then placed in a well oiled
bullet -mould, in which the end of a platinum wire is coiled.
By drying this paste in a moderately hot sandbath, a
compact mass of binoxide of manganese is formed, without
any kind of cement, and the ball can be easily removed
from the mould. The ball is the moistnened several
times over with a syrupy solution of phosphoric acid,
but not allowed to lose its compactness, so that it can
still be pushed under the mercury into the eudiometer.
If the moisture on the sides of the tube has disappeared
during the absorption of the sulphuretted -hydrogen, the
gas must be thoroughly dried by a ball of phosphoric
acid. These balls of phosphoric acid are easily made
by dipping the coiled end of a platinum wire into cooling
red -hot -liquid phosphoric acid, and covering the drop
of phosphoric acid hanging on the wire with the viscous
melted mass, until it has attained a spherical form of
the size of large pea. By observing all these precau-
tions, sulphuretted -hydrogen can be separated with great
SULPHURETTED - HYDROGEN.
85
accuracy from hydrogen, nitrogen, carbonic acid, hydro-
carbons &c., as may be seen from the following analyses
of a mixture of hydrogen, carbonic acid and sulphuretted-
liydrogen.
Vol.
Pres-
sure.
Temp.
C.
Vol. at
C. and
l m press.
Carbonic acid employed
71.2
G551
8.6
45 ^2
Alter addition of hydrogen ....
98.G
0.6817
8.8
65.12
After addition of sulphuretted - hy-
dro fen
139.0
720G
88
97 04
Alter absorption of sulphuretted-hy-
drogen
98.8
06813
9 3
65 10
Giving :
Carbonic acid . . . .
Hydrogen .
Sulphuretted hydrogen
Carbonic acid employed
After addition of sulphuretted -hy-
drogen
After absorption of sulphuretted-
hydrogen by binoxide of man-
ganese and phosphoric acid . .
The same operation repeated . . .
Employed.
46.60
20.51
32.89
100.00
Found.
4G.59
20.50
32.91
102.5
121.8
0.6990
0.7176
100.00
10.3
10.3
Carbonic acid ....
Sulphuretted - hydrogen
103.2
103.3
Found.
82.49
17.51
100.00
0.7005 10.3
0.6974! 10.7
I
Employed.
82.16
17.84
100.00
69.04
84.03
69.66
69.32
86 SPECIAL DETERMINATIONS.
The sulphuretted-hydrogen used in these experiments
was evolved from sulphide of iron. This gas can, there-
fore, be thus prepared in a chemically pure state, and un-
dergoes in contact with mercury so slow a decomposition,
that the result of the analysis is not sensibly altered.
In cases in which only traces of sulphuretted -hydro-
gen are present, another method is most conveniently em-
ployed, although the results are not so accurate as those
arrived at by the process just described. In this case the
carbonic acid and the sulphuretted-hydrogen are absorbed
together, by a ball of pure caustic potash. This ball must
contain a large quantity of water and must be introduced
into the gas, without being moistened externally, so that
on withdrawal none of the potash remains in contact with
the mercury. Distilled water acidulated with acetic acid
is then boiled in two flasks, until all the dissolved air has
been removed, and the water in one flask poured, whilst
boiling, into the other up to the top of the neck. The
flask is then well closed by a cork covered with a plate
of caoutchouc, so that no bubble of air is left between the
liquid and the caoutchouc plate. As the liquid cools, the
cork is pushed further into the neck, in order to prevent
the formation of a vacuous space, and the possible en-
trance of air. The ball of potash , cut off from its pla-
tinum wire immediately on withdrawal from the gas, is
allowed to dissolve in this liquid, when cool, and a few
drops of clear solution of starch are added. In this way
all the sulphuretted-hydrogen in the gas is dissolved in
the acidified water free from air and containing starch.
By means of an accurately graduated pipette a solution
of iodine of known strength (containing about 0.01 milli-
gramme of iodine in each division of the pipette), is added
to the acidified solution of the potash-ball, and the iodine
SULPHURETTED - HYDROGEN. 87
slowly dropped into the liquid, kept constantly stirred,
until the blue colouring of the starch has been observed,
marking the exact point at which the decomposition of
the sulphuretted -hydrogen is complete. The volume of
the sulphuretted -hydrogen is found from the amount of
iodine consumed, every milligramme of this substance
representing 0.087771 cbc. sulphuretted - hydrogen at
and O m 76.
In order to free the determination from any error
which might arise from impurities in the potash, the ex-
periment is repeated exactly in the same way with a ball
of the same potash , but containing no sulphide of pot-
assium, and the amount of iodine which has to be added
until the blue colouring occurs, subtracted from the
amount found in the previous experiment. In these ex-
periments it is adviseable, in order to obtain accurate
results, always to employ equal quantities of acetic acid
and starch, and not to take too large an amount of either
substance; it is also necessary, to have the solution con-
taining the sulphuretted-hydrogen so dilute, that less than
5 parts of this gas is contained in 1000 parts of the li-
quid. These precautionary measures were adopted in the
following experiment.
Vol.
Temp.
Pres-
Vol. at
C. and
C.
sure.
1 press.
Hydrogen
40.2
5.8
0.6497
9.409
After addition of sulphuretted-hy-
.
drogen .
64.3
5.6
0.6730
15.573
After absorption of the sulphuretted-
hydrogen by hydrate of potash .
40.4
5.4
0.6516
9.468
SULPHUROUS ACID.
Iodine required for decomposition
of the sulphuretted-hydrogen . . O0688
Iodine required in the control ex-
periment . . , . , . . O0009
Sulphuretted-hydrogen determined
as Iodine OO679 = 5.96 cbc.
Sulphuretted hydrogen found hy
absorption 6.10
If sulphuretted-hydrogen occurs merely with nitrogen,
hydrogen or other gases not absorbed by potash, it can
be determined by simple absorption with a potash -ball
like carbonic acid.
5. SULPHUROUS ACID.
Sulphurous acid occurs with carbonic acid as a very
largely diffused constituent of volcanic gases, and may be
determined in exactly the same manner as sulphuretted-
hydrogen. The following analyses of a mixture of carbo-
nic acid and sulphurous acid shows the great degree of
accuracy, which may thus be attained.
Vol.
Pres-
Temp
Vol. at
C. and
sure.
C.
1 press.
Carbonic acid employed . .
116.5
0.6720
19.8
73.00
Alter addition of sulphurous acid .
152.2
0.7071
19.8
100.35
After absorption with binoxide of
manganese and phosphoric acid
115.6
0.6901
19.6
72.94
Carbonic acid
Sulphurous acid
Found.
72.69
27.31
Employed.
72.75
27.25
100.00
100.00
HYDROCHLORIC ACID.
89
As a second example of this method, follows an ana-
lysis of gases mixed with air, which I collected from one
of the fissures in the large crater of Hecla, a few months
after the last great eruption of this volcano.
Vol.
Pres-
sure.
Temp.
C.
Vol. at
C. and
l m press.
vTclS CIfl.t)lovCQ
114.9
0.6944
20.4
74.24
Alter absorption with MnO* . . .
112.9
0.6958
20.4
73.10
After absorption with KO . HO . .
108.1
0.7092
20.6
71.29
Gas transferred
136.7
0.3460
20.6
43.98
After explosion with detonating gas
137.2
0.3452
20.7
44.02
After addition of hydrogen ....
190.4
0.3980
20.5
70.49
\ftcr the explosion
152.7
0.3585
20.3
50.96
After absorption with potash . . .
148.9
0.3665
18.9
51.04
Nitrogen 81.81
Oxygen 14.21
Carbonic acid 2.44
Sulphurous acid 1.54
100.00
6. HYDROCHLORIC ACID.
This gas can also be absorbed by a potash ball, like
the two preceeding substances, when no other acid gases
soluble in water are present.
The separation of hydrochloric acid from carbonic
acid, sulphuretted-hydrogen or sulphurous acid, although
it can be completely accomplished, is always attended
with some difficulty, particularly when the volume of hy-
90 SPECIAL DETERMINATIONS.
drochloric acid present is considerable, compared with
that of the other gases.
The hydrochloric acid is first determined after the
gas has been completely dried by a ball of phosphoric
acid. The absorption of the acid gas may be effected by
a ball of oxide of bismuth or oxide of zinc, which has
been plastered whilst moist on the bent end of a platinum
wire, and then ignited in the flame of a spirit-lamp. With
the former of these substances, however, the results ar-
rived at are somewhat too small, and with the latter,
somewhat too large. More exact results are obtained
by employing a neutral salt containing a large quantity
of water of crystallization. Sulphate of magnesia, or bo-
rax, but especially sulphate of soda answer extremely
well for this purpose. A ball of these substances is best
made by bending the end of a platinum wire into a coil,
and dipping the coil several times into the salt, melted
in its own water of crystallization, until a sufficient quan-
tity of it adheres to the platinum. If only a small quan-
tity of hydrochloric acid is present, this method gives very
exact results; but if a large quantity is to be absorbed, it
may often happen that the water of crystallization from
the sulphate of soda takes up more than a few percenta-
ges in weight of hydrochloric acid, and deliquesces to a li-
quid, which runs down the sides of the tube, rendering
the reading off difficult, and causing small quantities of
hydrochloric acid to diffuse with the aqueous vapour into
the gas. When this happens, the gas must be dried with
phosphoric acid, another ball of sulphate of soda intro-
duced, and the gas again dried by phosphoric acid. It
is, however, always better to take at first a ball of sul-
phate of soda lar^e enough to absorb the whole of the
hydrochloric acid in the proper manner.
HYDROCHLORIC ACID.
m
After separation of the hydrochloric acid, the sul-
phurous acid or sulphuretted - hydrogen is absorbed by
binoxide of manganese and phosphoric acid, and the car-
bonic acid determined by potash. An experiment con-
ducted in this way, gave the following results:
Vol.
Pres-
sure.
Temp.
C.
Vol at
0" C. and
1 press.
Carbonic acid and sulphuretted-hy-
drogen, dried by phosphoric acid
Alter addition of hydrochloric acid
After absorption with sulphate of
soda
104.8
167.4
105.6
104.0
ydrogeL
0.7187
0.7712
0.7199
0.7207
Emp
i 5*
j.1
13.7
13.7
13.7
132
loyed.
!.34
.66
71.72
122.94
72.56
71.52
Found.
58.18
41.82
Alter drying with phosphoric acid
This gives:
Carbonic acid and sulphuretted-h
Hydrochloric acid
100.00
100.00
7. HYDROGEN.
Hydrogen gas can be determined very exactly by
combustion with oxygen. This latter gas is best prepared
for gasometric purposes in small retorts (Fig. 37) of about
Fig. 37. 6 to 10 cubiccentimetre capacity,
blown before the blowpipe from
a glass tube. These retorts are
half filled with pulverised dry
chlorate of potash, and the end
of the tube at a afterwards bent
upwards. The air is first ex-
92 SPECIAL DETERMINATIONS.
pelled by a quick evolution of oxygen, and the gas then
allowed to rise immediately into the eudiometer, care
being taken not to add more than from three to four times
the volume of the hydrogen present.
The hydrogen amounts to two thirds of the volume
which has disappeared after the explosion. If the gas
contains absorbable constituents, these are determined be-
fore hand, in the absorption tube, and the residual gas
then transferred into the combustion eudiometer. In pre-
sence of nitrogen, considerable errors may ensue if the
temperature of the combustion be not lowered beneath
that at which a formation of nitric acid occurs. The re-
lation between the volumes of nitrogen and detonating
gas burnt, must, therefore, in every case be determined.
If this relation is less than 6 to 1, the analysis must be
repeated with addition of so much air, that this or a
larger proportion is attained. If, on the other hand, the
amount of hydrogen is very small, compared with the vo-
lume of non- combustible gas, a quantity of electrolytic
detonating gas must be added, until the point of com-
plete combustion has been reached. This detonating gas
disappears completely after the combustion, and therefore
does not need to be measured. The hydrogen employed
in both the following experiments was prepared by elec-
trolysis.
HYDROGEN.
Vol.
Pres-
Temp.
Vol. at
C. and
sure.
C.
1" press.
Air employed
2G9.4
0553G
5 2
146 36
After addition of hydrogen ....
297.4
0.580G
5.4
169.45
After the explosion ... ...
255.1
0.5386
5 5
134 69
Employed. Found
Air 84.23 84.16
Hydrogen 15.77 15.84
100.00
100.00
A similar degree of accuracy maybe attained in mix-
tures containing only a trace of hydrogen.
Vol.
Pres-
Temp.
Vol. at
C. and
sure.
C.
l m press.
Original volume of air .
269.7
0.5585
5.9
150.49
After addition of hydrogen ....
271.6
0.5610
5.9
152.29
After addition of detonating gas .
358.4
0.6448
5.9
226.21
After the explosion
268.1
0.5574
5.9
149.37
Air . . .
Hydrogen
Employed. Found.
. 98.82 98.72
1.18 1.28
100.00
100.00
As an example of a complicated mixture of gases con-
taining hydrogen from a natural source, I append an ana-
lysis of a gas, which I collected in the summer of 1846,
from the great fumarole - fields of the Krafla- and Leyrh-
uukr- Volcanoes at Namarfjall in Iceland.
94
SPECIAL DETERMINATIONS.
Vol.
Pres-
sure.
Temp.
C.
Vol. at
C. and
1 press.
Gas employed
94
6945
13 3
62 35
After absorption of the H S . ':,. . .
After absorption of the CO 2 .
73.7
46.1
0.6728
0.6502
13.6
13.6
47.23
28.55
Gas transferred
After addition of air
96.8
243
0.3093
4534
13.1
13 6
28.57
10506
After the explosion
172
3839
13 7
62 88
After treatment with potash . . .
168.6
0.3902
13.1
62.78
Hydrogen 45.07
Sulphuretted -hydrogen 24.25
Carbonic acid . . _.^. : . 29.96
Nitrogen ', -. . ...... . 0.72
Carbonic oxide . . . . .-...;, ... 0.00
Hydrocarbons 0.00
100.00
8. CARBONIC OXIDE.
y. Vol. c + y 2 Vol. o = i vol.
Carbonic oxide can be separated from light -car-
buretted-hydrogen, hydrogen, nitrogen, carbonic acid &c.,
by means of a concentrated solution of subchloride of
copper brought into the tube on a ball of papiermache.
The carbonic acid is first determined by a potash - ball,
then the carbonic oxide by subchloride of copper, and
lastly a potash -ball is again introduced to free the gas
from the vapour of hydrochloric acid evolved from the
acid chloride. If oxygen is present, it is removed by
CARBONIC OXIDE.
95
pyrogallate of potash before the subchloride of copper is
introduced.
The carbonic oxide used in the following experiment
was prepared by slightly heating a mixture of formic and
sulphuric acids, and to ensure the perfect purity of the
gas, it was passed through a concentrated solution of
caustic potash.
Vol.
Pres-
Temp.
Vol. at
C. and
. V
sure.
C.
l m press.
Original mixture of N, HandCH 2
80.3
0.6785
1.8
54.32
After addition of CO
107 4
0.71G 9
05
76 78
After absorption with subchloride
of eoDDer .
80.0
0.6813
1.8
54.35
Employed. Found.
Gaseous mixture .
. . . 70.75 70.79
Carbonic oxide . .
, . . 29.25 29.21
100.00 100.00
Carbonic oxide may be more accurately estimated by
combustion with oxygen , and absorption of the carbonic
acid produced, by potash. If the mixture is not infla-
mable , electrolytic detonating gas must be added until
the requisite point of combustibility has been "reached.
The gases containing carbonic oxide which escape as
products of combustion from the burning materials in a
wind furnace, are best analysed according to this latter
method. As an example of this process I choose an ana-
lysis of a gas collected in 1845 from a boring 6 feet
above the hearth in the wall of a blast - furnace of the
Schonstein iron works in the Electorate of Hesse , where
9G SPECIAL DETERMINATION'S.
the fuel used was charcoal. The gas thus collected con-
sists entirely of nitrogen, hydrogen and carbonic oxide.
In order to obtain the amounts of x carbonic oxide
and y hydrogen, the following values are to be substituted
in the general formula on page 57.
P total volume of both gases.
P\ = volume of carbonic acid formed.
a = 1 b = 1
a, = 1 bj_ =
Hence
x = P,
y = P P!.
The contraction C observed on the combination of
the gases may serve as a control for the correctness of
the analysis.
On combustion of as volumes of carbonic oxide
-\- x volumes of carbonic oxide disappear, also
-(- !/ 2 x volumes of oxygen disappear, and
- os volumes of carbonic acid are produced.
Hence the contraction from the combustion of the
carbonic oxide amounts to 1 / 9 x. On the combustion of
y vol. hydrogen, l / 2 y vol. oxygen and y vol. hydrogen dis-
appear, or together 1 J /2 y volumes. If the gas really only
contains hydrogen and carbonic oxide, we must there-
fore have:
1/2 #+ IVay C= 0.
The following are the operations,. which must be per-
formed. In the first place, the absence of carbonic acid,
which would render the combustion - analysis erroneous,
must be proved:
CARBONIC OXIDE.
Vol.
Pres-
Temp.
Vol. at
C. and
sure.
C.
l m press.
Gas employed
98 9
6313
9 5
60 34
After absorption with potash . . .
97.7
0.6391
9.7
60.30
From this experiment we see that carbonic acid was
not present, we have, therefore, only to explode the com-
bustible gases with oxygen. If, as in the present case, it
is thought that the combustion would not be complete
owing to the large excess of nitrogen, a measured quan-
tity of hydrogen, or better of electrolytic detonating gas,
which, as we have seen, leaves no residue on explosion,
must be added. An analysis thus made gave the follow-
ing results:
Vol.
Pres-
sure.
Temp.
C.
Vol. at
C. and
1 press
Gas employed
149.7
0.4629
10.0
66.85
Alter addition of hydrogen ....
Alter addition of oxygen ....
After the explosion
172.8
263.8
219.3
0.4842
0.5761
0.5317
9.9
9.8
9.7
80.75
146.71
112.61
After absorption of the carbonic
182.8
05022
9.7
88.65
After addition of hydrogen ....
After the explosion
372.9
212.9
0.6854
0.5225
8.8
8.8
247.62
107.77
The gas in the four first observations was measured
whilst moist, the remaining observations were made after
the gas had been dried by a potash-ball. The measure-
ment of the latter volumes must be made whilst the gas
7
98 SPECIAL DETERMINATIONS.
is perfectly dry, as it often happens that after absorption
of the carbonic acid, a certain amount of moisture remains
attached to the walls of the eudiometer, and to the mer-
cury, which evaporates on admission of hydrogen, but
owing to the presence of potash on the side of the tube,
cannot attain the amount of tension corresponding to the
temperature of the gas. In order to avoid the tedious
process of drying the gas, which even with a hard ball of
potash takes from 10 to 12 hours, it is adviseable, to
transfer a portion of the gas, in which the combustion,
and absorption of the carbonic acid has already been
made, into another combustion-eudiometer and to analyse
the gas, thus freed from contact with potash, in the moist
state according to the methods given under oxygen and
nitrogen. By means of a simple proportion the amount
of oxygen and nitrogen contained in the total volume is
then obtained from the analysis of the portion trans-
ferred.
The volume of gas 66.85 originally employed, does
not consist of combustible gases alone , but contains
a quantity of nitrogen, which has to be determined.
The volume 88.65 , after absorption of the carbonic acid,
contains no gas besides this nitrogen and so much of
the added oxygen as remained after the explosion had
occurred.
The amount of this oxygen is, however, Vs * the
contraction ensuing from the combustion with hydrogen, it
is therefore - - = 46.62. The nitrogen pre-
o
sent in the gaseous mixture hence is 88.65 46.62=42.03.
This 42.03 subtracted from the original volume 66.85,
gives the amount of combustible gases to be 24.82 P.
The value of PI from the carbonic acid formed by the
MARSH GAS. 99
combustion is found to be P l 112.61 88.65 = 23.96,
and the contraction occurring from the combustion
146.71 112.61 = 34.10.
This contraction is caused not only by the com-
bustible gases originally present, but also by the 13.90 vo-
lumes of hydrogen added. This quantity of hydrogen
produces a contraction of .% X 13.90 = 20.85 volumes.
which must be subtracted from the total contraction 34.10.
in order to obtain the contraction C produced by tin-
combustible gases originally present; hence
C 34.10 20.85 = 13.25.
The following values of x and y are obtained when
the numbers just found are substituted in the respective
equations.
x == 23.96
= 0.86
Thc mixture of gases, therefore, consists of:
Carbonic oxide ..... 35.84
Hydrogen ....... 1.29
Nitrogen ....... 62.87
100.00
9. LIGHT CARBriJETTEI) -HYDROGEN.
MARSH (IAS.
1 , vol. C -f- 2 vol. H = 1 vol.
If nitrogen has to be estimated in presence of light
rurburetted- hydrogen. care must be taken to dilute the
\vith so much atmospheric air. that the temperature
of the explosion rerun ins low enough to prevent the for-
mation of nitric acid. We 1m ve already seen, that on
combustion of a mixture of hydrogen and nitrogen the
100 SPECIAL DETERMINATIONS.
production of nitric acid was prevented, when from 2 to 5
parts of non- combustible is present for every part of
combustible gas. In the analysis of light carburetted-hy-
drogen, as well as of all the hydrocarbons, in which se-
veral volumes of hydrogen are condensed into one vo-
lume, it is necessary to employ a still greater dilution.
When from 8 to 12 volumes of air and 2 of oxygen
are taken to one of the gas to be examined, accurate re-
sults are obtained even when the gas consists of pure
light carburetted- hydrogen. If the volume of this latter
gas, however, forms only a small fraction of the total quan-
tity of gas , the explosion does not occur with this great
dilution, and electrolytic detonating gas must be added
until the required point of combustibility has been at-
tained. The detonating gas must be well mixed with the
non - combustible gases before explosion; this is best ac-
complished by setting the column of mercury in the eu-
diometer into longitudinal vibration. It is unnecessary
to measure the exact volume occupied by the detonating
gas as it entirely disappears on explosion. Carbonic
oxide and hydrogen , when accompanying the marsh gas
in presence of nitrogen, can both be determined by a
simple combustion. If we call the volume of carbonic
oxide tf , that of the marsh gas ?/, and that of the hydro-
gen z, we have the following numbers to be substituted
in the general formula developed on page 57 :
cr=l 6=1 c=l A = 1/2 #== V2 C= 3 A
a 1= 1 b l= =l Cl = A!= 8/2 B I= Q = %
a,z=i/ 2 6 2 =2 Ca = V2 A 2 = \ B 2 = I C 2 =
Hence are derived the following equations, in which P re-
presents the volume of the combustible gases, P 2 the oxy-
gen combined, and JP, the carbonic acid formed during
he combustion.
MARSH GAS.
101
y =
2 P, P
The following analysis may serve as an example of
this process. The gas was collected in July 1848, from
the mud of a pond in the Marburg botanical garden, and
was freed from carbonic acid by potash before it was
analysed.
&
Vol.
Pres-
sure.
Temp.
C.
Vol. at
C. and
l m press.
Original gas employed
120.5
0.3144
18.6
35 47
Alter addition oi' air .
271 9
0.4G37
19
117 88
After addition oi' oxygen
312 2
05037
19 2
146 92
Alter the explosion
264.9
0.4550
19.4
112.54
Alter absorption of carbonic acid .
After addition of hydrogen ....
After the explosion . . .
233.6
320.3
278.7
0.43G6
0.5252
04670
19.3
19.4
19.7
95.26
157.07
121 41
The quantity af air added amounted to 82.41 vol-
umes, in this are contained 65.14 volumes nitrogen and
17.27 volumes oxygen, as is calculated in the following
manner by means of table VII in the appendix
80.00 vol. of air contain
2.00
0.40
0.01
63.2320 vol. nitrogen,
1.5808
0.3161
0.0079
82.41 vol. of air contain therefore 65.1368 vol. nitrogen.
102 SPECIAL DETERMINATIONS.
80.00 vol. of air contain .... 16.7680 vol. oxygen,
2.00 .... 0.4192
0.40 .... 0.0838
o.oi .... o.oo& -, :
82.41 vol. of air contain therefore 17.2713" vol. oxygen.
These 17.27 volumes of oxygen together with the
29.04 volumes of that gas added, make a total of 46.31
volumes. After the absorption of the carbonic acid formed
on combustion, a residual volume of 95.26 was observed,
and this could only contain nitrogen and unburnt oxygen.
On exploding this gas with excess of hydrogen, a con-
traction of 35.66 was found. The third part of tl^s
volume, or 11.89, gives the amount of oxygen contained
in the 95.26 volumes of residual gas. The difference
between 95.26 and 11.89, or 83.37, is the volume of nitrogen
originally present in the gas, plus that added as at-
mospheric air. By subtracting the volume of nitrogen
added in the air, 65.14. from the total quantity of this
gas, 83.37, we obtain the amount originally present in
the gas, namely 18.23; hence the volume of the com-
bustible gases employed in the analysis is found to be
17.24 = P. The amount of oxygen combined during the
combustion is found, by subtracting the residual amount
11.89 from the total amount added, to be 34.42 = P.,.
The experiment also gives the volume of carbonic acid
formed to be P } = 17.28. By substituting these values
in the formula we obtain:
Marsh gas .... 17.20
Nitrogen .... 18.23
Carbonic oxide . 0.08
Hydrogen . . . . - 0.04
35.47
OLEFIANT GAS. 103
As the volumes of carbonic oxide and hydrogen are
found to be so small that they fall within the limits of
experimental error, we may conclude that the gas con-
sists entirely of hydrogen and nitrogen. If the experiment
had given a large negative value for any constituent, it
would show that the gas which has been examined con-
tained other gases than those under consideration, and
that, therefore, the suppositions upon which these for-
mula 1 are founded, are incorrect.
Therefore, according to analysis, in 100 parts the gas
consists of:
Marsh gas 48.5
Nitrogen 51.5
Carbonic oxide ... 0.0
Hydrogen 0.0
10. OLEFIAXT GAS. KLAYL.
1 vol. C 4- 2 vol. H = 1 vol.
In order to determine the amount of elayl by ab-
sorption, a concentrated but still liquid solution of an-
hydrous sulphuric acid in monohydrated sulphuric acid
is employed. This solution is brought into the dry gas
by means of a coke -ball, and thus after the absorption
of the elayl is complete, the acid fumes, which have dif-
fused throughout the gas, are removed by a ball of
potash.
If the gas contains other absorbable gases, as, for
instance, sulphurous acid, carbonic acid, and oxygen, the
sulphurous acid must be first determined, then the car-
bonic acid, then the elayl, and lastly the oxygen.
104
SPECIAL DETERMINATIONS.
As an example I have chosen a mixture of air and
olefiant gas.
Vol.
Pres-
Temp.
Vol. at
C. and
sure.
C
l m press.
Olefiant gas ... . . .
G7.2
0.5731
15.2
36.48
After addition of air .
140 1
6431
15 2
85.35
After absorption by SO 3 and KO HO
68.2
0.5657
15.2
36.55
Employed.
Found.
Olefiant gas .
.-.' 57.25
57.18
Air . . . .
42.75
42.82
100.00
100.00
Olefiant gas may be still more exactly determined
by combustion with oxygen. If the quantity of oxygen
added be not very much more than that required for
combustion, the explosion will be so violent that the
eudiometer may be broken. The gas must, therefore, be
so diluted with atmospheric air, that for one part of the
explosive mixture, about twenty parts of non-combustible
gas is added. Very accurate results are then obtained,
as may be seen from the following analysis made by
Dr. Carius. The olefiant gas employed was prepared by
the action of sulphuric acid on alcohol, and to free it
from all impurities it was first left in contact with sul-
phuric acid, and afterwards with a ball of potash.
OLEFIANT GAS.
105
Vol.
Pres-
sure.
Temp.
C.
Vol. at
0C. and
l m press.
36.7
311.2
339.8
318.0
290.1
0.2443
0.5183
0.5402
0.5261
0.5130
12.0
12.0
12.5
12.0
11.2
8.64
154.52
177.48
160.26
142.96
P = 8.64,
P l = 17.3,
Po = 25.91.
Original gas
After addition of air
After addition of oxygen . . .
After the explosion
After absorption of carbonic acid
These experiments give:
The volume of gas employed . . .
the volume of carbonic acid formed
the volume of oxygen burned . .
If the gas had still contained two other constituents
of known composition, the amounts of these could have
been calculated from the three values P, P x , P 2 . If we
substitute these values in the formula for elayl, and two
other gases, for instance carbonic oxida and marsh gas,
the calculation must give the value for the latter gases
to be 0, or something very near 0, if the gas consists
merely of elayl.
The equations of condition for a mixture of ,r elayl,
y carbonic oxide, and z marsh gas, are found from the
following values by means of the general formula pre-
viously developed.
a = 1 b=l c=l .4=+1.5 =-1 (7= 2
/ 1= =2 &i= 1 cj=l .4!= 1.5 B 1= =l C^ =4-2.5
x = P! - - P
2 P l 4- 2 P 2 P 2
y ==
z =
3
4P-f2P 2
3
106 SPECIAL DETERMINATIONS.
By substituting the experimental values of P, Pj,
and P 2 we have:
Elayl . v , 8.66
Carbonic oxide -f- 0.02
Marsh gas . . - 0.04
It is seen that the amounts of the two last gases fall
within the limits of the experimental errors.
As a second example I cite an analysis made by
Dr. M. Hermann, of the remarkable mixture of gases
evolved by the action of an alcoholic solution of potash
on terbromide of formyl :
Vol.
Pres-
Temp.
Vol. at
0C. and
sure.
C.
l m press.
Ocis employed ...
141 4
1763
16 9
23 48
After addition of oxygen . .'-.';
356.8
0.3857
16.9
129.60
Alter the explosion V; ... .
325.4
0.3563
16.8
109.23
After absorption of carbonic acid
268.7
0.3159
17.2
79.86
P = 23.48
P l = 29.37
P 2 = 26.26.
These values substituted in the formula* give:
Elayl . ; v .^ : . '. 5.89
Carbonic oxide 17.73
Marsh gas . ~~*. - 0.14
If the nature of the constituents of the gas had been
doubtful, the close approximation of the value found for
marsh gas to 0, would render it very probable that he
assumptions upon which the equations rested were
TETRYLENE.
107
correct; that is. that the gas actually was composed of
elayl and carbonic oxide alone, and in the following
proportion :
Carbonic oxide . 75.0(i
Elayl .... 24.94
100.00
11. DITETRYL GAS. TETRYLENE.
2 vol. C -f 4 vol. H 1-vol.
Ditetryl gas occurs together with elayl amongst the
products of the dry distillation of coal. Like this latter
gas, and like almost all the hydrocarbons of the form
CiiHn. it is completely absorbed by fuming sulphuric-
acid. Even in presence of elayl there is no difficulty in
the quantitative estimation of ditetryl. An example will
most clearly explain the process adopted in this case.
For this purpose, I have chosen Manchester coal gas
prepared from cannel coal, containing eight constituents,
namely sulphuretted -hydrogen, carbonic acid, nitrogen,
carbonic oxide, marsh gas, hydrogen, elayl, and ditetryl.
The sulphuretted -hydrogen and carbonic acid are first
determined in the absorption tube. The following results
were obtained:
Vol.
Pres-
I. enip.
Vol. at
C. and
sure.
C.
1 press.
Gas originally employed . . .
120.5
0.7250
2.8
86.48
After absorption of sulphtiretted-
-
hvdro^eu ... . . -. .
120.0
7259
2.8
8C>.2;3
Alter absorption of carbonic acid
114.4
0.7341
3.0
83.06
108 SPECIAL DETERMINATIONS.
Hence the composition of the gas is,
Sulphuretted - hydrogen
Carbonic acid .' . /
Elayl
Ditetryl
Nitrogen
Carbonic oxide
Hydrogeji
Marsh gas
. 0.25
3.17
83.0H
86.48
The following separate analyses were then made of
the residual gas thus freed from sulphuretted - hydrogen
and carbonic acid. The total volume of both elayl and
ditetryl is determined, in a portion A of the gas, by ab-
sorption with fuming sulphuric acid. The residual gas
B, remaining after this absorption, is then transferred
into the combustion -eudiometer, and analysed by com-
bustion with oxygen as previously described. This same
combustion - analysis is lastly made with a portion C of
the original gas, from which the sulphuretted - hydrogen
and carbonic acid, but not the elayl or ditetryl, have
been separated.
Analysis A.
Vol.
Pres-
Temp.
Vol. at
C. and
sure.
c.
l m press.
Gas originally employed . . .
103.1
0.72G6
3.3
74.02
After absorption with sulphuric
96.5
0.7217
2.4
69.04
Hence.
ANALYSIS OF COAL GAS.
b.
4.98
109
Ditetryl)
Elayl |
Nitrogen
Carbonic oxide
Hydrogen
Marsh gas
69.04
74.02
If this composition is calculated to the volume 83.06
of the analysis a. , we have
c.
Sulphuretted -hydrogen . . 0.25
Carbonic acid ..... 3.17
Elayl
Ditetryl
Nitrogen
Carbonic oxide
Hydrogen
Marsh gas
5.59
77.47
86.48
The composition of the 77.47 volumes of gaseous
mixture is found from
Analysis B.
Vol.
Pres-
sure.
Temp.
C.
Vol. at
C. and
1 press.
Original gas employed ....
After addition of air ...
256.0
750.7
0.3395
7358
2.0
2.2
86.28
547.90
After addition of oxygen . . .
After the explosion
814.3
688.0
0.7394
0.6754
2.2
2.2
597.25
*460.95
After absorption of carbonic acid
645.1
0.6537
0.5
420.94
After addition of hydrogen . .
819.0
0.7490
0.5
612.30
After the explosion ....
G75.3
0.6696
0.6
451.16
110 SPECIAL DETERMINATIONS.
Gas employed 83.91
Oxygen burnt . . 1 . . 92.39
Carbonic acid formed . . 40.01
Nitrogen . v- ...' . 2.37
Nitrogen . . .^ 2.37
Carbonic oxide . 6.39
Hydrogen . . . 43.90
Marsh gas ... 33.62
S6.28
Calculated to the 77.47 volumes of analysis c., this
gives
d.
Sulphuretted -hydrogen . . 0.25
Carbonic acid ."., .1 V ^3.17
Elayl )
Ditetryl i
Nitrogen . . . /." . . 4 ' .''*'' 2.13
Carbonic oxide . . . ;* ? ' 5.74
Hydrogen .Jr. ^U'to^. 39.42
Marsh gas 30.18
86.48
In order to determine the relation of the elayl to
the ditetryl, an analysis is made with another portion C
of the gas , containing all the constituents with the
exception of the carbonic acid and sulphuretted - hy-
drogen.
ANALYSIS OF COAL GAS.
Analysis C.
in
Vol.
Pres-
Temp.
Vol. at
C. and
sure.
C.
l m press.
Gas employed
70.5
0.1593
3.2
11.10
After addition oi' air
294.1
0.3583
2.3
104.46
After addition of oxygen . . .
343.2
0.4008
3.0
136.0G
After the explosion
315.9
0.3775
3.0
117.90
After absorption with potash . .
297.2
0.3781
3.2
111.07
The volume of gas employed 11.10 consists there-
ore of.
e.
0.747
Elayl I
Ditetryl i
Nitrogen 0.284
Hydrogen 5.268
Carbonic oxide .... 0.767
Marsh gas 4.034
11.100
The quantities ol hydrogen, carbonic oxide, and
marsh gas contained in these 11.10 volumes, must have
given a contraction on combustion of 16.353 volumes,
and an amount of carbonic acid equal to 4.801 volumes.
The same volume of gas containing 0.747 volumes of elayl
and ditetryl gave when burnt, according to analysis C,
18.100 volumes contraction, and 6.890 volumes of carbonic
acid. The contraction ensuing from the combustion or
the elayl and ditetryl, alone amounted therefore to 18.100
- 16.353 = 1.747, and the carbonic acid formed from
0.747 volumes of the two gases amounted to 6.890
112 SPECIAL DETERMINATIONS.
- 4.800 = 2.090. Hence the following elements for cal-
culation are obtained:
Volume, of gas employed . . 0.74.7 A,
Carbonic acid formed ... 2.0M B,
Contraction on combustion . 1.747 C.
One volume of elayl (1vol. C -f- 2vol. H) gives 2 vol-
umes of carbonic acid, and 2 volumes contraction. One
volume of ditetryl (2 vol. C -f- 4 vol. H) gives 4 volumes
of carbonic acid, and a contraction of 3 volumes.
The proportion between the two gases calculated
from the sum of their volumes A, and from the amount
of carbonic acid produced on their combustion /?, is
found by the following equations in which x represents
the amount of the elayl and y that of the ditetryl.
1) x + y = A,
2) 2 x + 4 y = B,
' ? B 2 A
y-- -y--,
B 2 A
TT
By substitution of the experimental values of A and
B we have,
Ditetryl 0.298
Elayl 0.449
0.747
The contraction C gives a third formula
3) 2 a + 3 y = <7,
which combined with equation 1) gives the values of x
and y to be
y = C 2 A,
x = A C2 A.
ANALYSIS OF COAL GAS. 113
The composition derived from these values is,
Ditetryl .... 0.253
Elayl 0.494
0.747
The close agreement in the numbers of both these
determinations, may be regarded as a confirmation of
the supposition that the gases consisted entirely of a
mixture of elayl and ditetryl. The mean of these two
determinations calculated for the 5.59 volumes of elayl
and ditetryl found in analysis d., gives the following as
the composition of the coal gas.
Nitrogen 2.13
Sulphuretted -hydrogen . . 0.25
Carbonic acid 3.17
Elayl 3.53
Ditetryl 2.06
Carbonic oxide 5.74
Hydrogen 39.42
Marsh gas 30.18
86.48
or in 100 parts
Hydrogen 45.58
Marsh gas . . 34,90
Carbonic oxide 6.64
Elayl 4.08
Ditetryl 2.38
Sulphuretted -hydrogen . . 0.29
Nitrogen 2.46
Carbonic acid 3.67
100.00
This gas thus contains 8 constituents, and among these
6 are combustible. If another hydrocarbon absorbable
8
114 SPECIAL DETERMINATIONS.
by sulphuric acid were present as the ninth constituent,
it could also be determined by means of formulae 1, 2,
and 3. Even if another non-absorbable hydrocarbon be
present as tenth constituent, it can be estimated when
the carbonic oxide has been previously removed by sub-
chloride of copper. Lastly, another equation is obtained,
by help of which an eleventh constituent may be deter-
mined, when the volume of aqueous vapour generated
during the combustion is measured according to the
method previously described.
As the quantity of oxygen contained in such a
mixture of gases can be easily determined by absorption
with pyrogallate of potash, it is seen that by means of
gasometric analysis, twelve gases, some of them com-
bustible and some non- combustible, can be completely
separated from each other.
12. M T H Y L.
. 2 vol. C -j- 5 vol. H = 1 vol.
The analysis of sethyl, and of all the gaseous hydro-
carbons which contain their constituents in a very con-
densed state, can be made like that of elayl and ditetryl;
but in proportion as the condensation becomes greater,
must the amount of air added be increased. Thus, for
example , in order to burn 1 volume of ffithyl containing
7 volumes of carbon and hydrogen, it is necessary to
add a volume of air from 20 to 24 times as great as the
volume of sethyl, and from 6 to 7 times the same volume
of oxygen. It is, therefore, most convenient to employ
for such analysis an eudiometer from 0.8 to 1.0 metre in
length.
jETHYL GAS.
115
As an example of an analysis of pure sethyl I cite
an experiment made some time ago by Professor Frank-
land in my laboratory.
Vol.
Pres-
Temp.
Vol. at
C. and
sure.
C.
1 press.
91.8
0.1186
12.8
10.40
471.2
0.5215
13.0
234.56
After addition of oxygen . . .
535.1
0.5800
12.9
296.35
498.8
0.5461
12.8
260.19
After absorption of carbonic acid
454.3
0.5043
13.0
218.69
After admission of hydrogen . .
644.7
0.6769
13.1
416.41
After the explosion
532.7
0.5770
13.0
293.39
Gas employed . .
Oxygen burnt . .
Carbonic acid formed
Found.
10.40
67.26
41.50
Calculated.
10.36
67.35
41.45
The close agreement between the numbers found by
experiment, and those calculated from the formula
2 vol. C -)- 5 vol. H = 1 vol., shows that the gas under
examination consisted of pure sethyl.
11G DETERMINATION OF THE
SPECIFIC GRAVITY OF GASES.
A he specific gravities of various gases are represented
by the weights which equal volumes of these gases
possess. As the volume occupied by a given weight of
any gas, is dependant upon the variations of the force
of gravity accompanying change of geographical latitude,
or elevation above the sea's level, all gases, of which the
absolute volumes are required, must be reduced to the
same latitude and elevation above the sea, and to the
same barometric pressure and temperature.
According to the most accurate experiments, for
which we are indebted to the classical labours of Reg-
nault, one gramme of atmospheric air at the level of the
sea, in the 45th degree of latitude, at 0C., and under
a pressure of O m 76 of mercury, occupies a volume of
773.526 cubic -centimetres. For a latitude qp, and at an
elevation of h toises * above the mean level of the sea,
this volume is found from the following expression;
7=773.520.
1 _ 0.0025935 cos 2 <p '
* A toise is equal to 1.9491 metres pretty nearly equal to an
english fathom.
SPECIFIC GRAVITIES OF GASES. 117
in which the number 3266322 signifies the length of the
earths radius in toises.
In the latitude 52 36', as, for instance, in Berlin, a
gramme of dry air at 0C., and under a pressure of O m 76
occupies exactly 773 cubic -centimetres.
The accuracy of gasometric determinations is seldom
so great, that the differences resulting from the variation
of gravitation extend beyond the limit of the possible
observational errors. Hence, excepting in normal de-
terminations when the greatest accuracy is required, the
volume of 1 grm. of dry air .at C., and O m 76 pressure
of mercury, may be represented in our latitudes by
773 cubic - centimetres ; and the specific gravity of a gas
may be defined to be, the weight in grammes of gas
which, under the same conditions, occupies a space of
773 cubic - centimetres.
The vertical column of table V in the appendix
headed ,,Spec. grav." contains the specific gravities of the
more common gases and their constituents. The numbers
for oxygen, hydrogen, and nitrogen are those found by
Regnault from direct experiment, the remainder are cal-
culated from the following atomic weights according to
Gay-Lussac's law of volumes.
= 100.00 Fl = 120.00
S = 200.00 Sb = 806.25
Se = 491.20 As = 468.75
Te = 806.50 Ph = 193.75
Cl = 221.87 Si = 266.25
Br = 489.40 Bo = 136.25
1 = 794.37 C = 75.00
The basis of this calculation is founded upon Reg-
nault's fundamental experiment, according to which 1000
118
METHODS OF DETERMINING
cubic - centimetres of oxygen in latitude 52 36', at the
mean sea's level, and at 0C. and 0.76 pressure of mer-
cury, weigh 1.43028 grammes.
The determination of the specific gravity of gases
and gaseous mixtures is a very important operation in
gasometric researches.
In cases in which a normal determination is not
required, a common light flask, g, Fig. 38, is employed
for measuring the volume of gas of which the specific
Fig. 38.
gravity is to be estimated. The volume of the flask should
be about 200 or 300 cubic - centimetres , and the neck a,
thickened before the glass blowpipe, must be drawn out
so as to have an aperture of the thickness of a straw,
into which a glass stopper is ground air-tight by means
of emery and turpentine. Through this neck, which is
furnished with an etched scale in millimetres, mercury
is poured, by means of a funnel reaching to the bottom
of the flask, until the whole is filled. As soon as this
THE SPECIFIC GRAVITIES OF GASES. 119
is accomplished, the flask is transferred, with its mouth
downwards, into the mercury trough A A, and gas is
allowed to enter, until the level of mercury in the neck
of the flask stands a few millimetres higher than that in
the trough. In order to secure the absence of all gaseous
impurities, this gas is evolved from as small a vessel as
possible, and allowed to enter the flask through a narrow
delivery tube and in the moist state. The gas is dried
in the flask itself by a small piece of fused chloride of
calcium 6, which had previously been made to crystallise
on the side of the flask by bringing if in contact with a
single drop of water, and alternately heating and cooling
the glass. This small piece of chloride of calcium serves
also to free the mercury and the sides of the flask from
all adhering moisture. In order to be able to close the
flask at any time without warming it with the hand, the
little lever cf is employed. On the lower end /of this
lever the stopper is so fastened in a cork, that it passes
into the neck of the flask without closing it, and the
lever is held in its right place by a wedge d, pushed
under the finger plate c. As soon as the apparatus has
attained the constant temperature t at the barometric
pressure P, the volume V of the gas , and the height p
of the column of mercury rising above the level of the
metal in the trough, are observed with the cathetometer
telescope. If the observed volume of gas in cubic -centi-
metres reduced from a table of capacity, be represented
by F n this volume at 0C. and 0.76 pressure becomes in
cubic - centimetres :
v
"
0.76 (1 + 0.00366 t)
It is now only necessary to determine the weight G 2
of this volume K 2 . This is obtained in the following
120
METHODS OF DETERMINING
Fig. 39.
manner: the wedge d is taken away, the flask is thereby
closed, and by withdrawing the pin e, it can then be
removed, together with the lever c/, from the trough.
After having been most carefully freed from all adhering
matters, and having attained the temperature ^ of the
balance, by the pressure Pj, the flask can be weighed.
Let G represent the weight in grammes thus found. The
glass stopper is now re-
moved and replaced by a
caoutchouc tube connect-
ed with a drying tube 6,
Fig. 39. The apparatus
thus arranged is placed
under the receiver of an
air-pump, and the air
so often withdrawn and
admitted until all the
gas has been replaced by
dry air. If this weight
amounts to G l grammes,
the weight 6r 2 of the vol-
ume of gas V 2 measured
in the flask is equal to
Vi Pi
773 X 0.76 X (1 -f 0.00366 t,)
From this value G 2 , the specific gravity is obtained
by the help of the following formula,
O r? f? O ^-"2
o = i (6 -=.
* The unequal specific gravity of the glass and mercury on the
one hand, and the metal weights on the other, is not con-
sidered in this calculation, as the inaccuracy thus introduced
is inconsiderable in comparison to the observational errors.
THE SPECIFIC GRAVITIES OF GASES. 1*1
I cite as an example of this determination a vapour-
density of gaseous bromide of methyl, made with a small
balloon of about 44 cubic -centimetres capacity. Ob-
servation gave :
V l 42 CC 19 G = 7*9465
P = O m 7464 G l = 7*8397
p = O m 0243 P l =rO m 7421
t = 1608 C. t, = 6<>2 C.
The specific gravity calculated from these numbers
is 3.253. According to the chemical composition it should
have been 3.224, for
2 X 773 cbc. carbon vapour . . . = 1.6584
6 X 773 hydrogen ..... = 0.4156
2X773 bromine vapour . . =10.8217
4 X 773 bromide of methyl . = 12.8957
1X773 bromide of methyl . = p = 3.2239
It often happens that only a few cubic -inches of gas
are placed at the disposal of the analysist. The amount
of material remaining after the necessary analyses have
been made, is therefore often insufficient for the deter-
mination of the specific gravity of the gas according to
the process just described. In such cases I employ an-
other method which gives results of sufficient accuracy
even with two cubic -inches of gas.
This method is based on the fact that the specific
gravity of two gases, which stream out of a fine opening
in a thin plate, are very nearly proportional to the square
of the time of effusion. If a gas of specific gravity s requires
the time ?, and another gas of specific gravity s 1 requires
the times ^, the relation between the times of effusion,
and the specific gravities is represented by the equation
122
METHODS OF DETERMINING
- = -^-. If s, or the specific gravity ol one gas, be
made equal to 1, the specific gravity of the other is found
2
from the formula s { = -.
Fig. 40 represents the apparatus which is employed
Fig 40 f r these determinations. The glass tube
a a of about 70 cbc. capacity, and open
at bottom, is furnished with a glass stop-
cock at c, into which the small glass tube
e is ground air-tight at d. This small
tube is closed at the upper end by a thin
piece of platinum foil melted on to the
glass, and pierced by a very small aper-
ture. In order to render the foil as thin
as possible, and the opening extremely
small, a hole is bored through the metal
with a fine needle, and the platinum,
thus pierced, beaten out with a polished
hammer on a steel anvil until the hole
is not perceptible to the ordinary eye,
and is only just seen when the foil is
held close between the eye and a bright
flame. The foil is then cut into a small
round disk in the centre of which is
placed the fine aperture. This small disk
of metal is easily melted on the upper
end of the small tube ed, by laying it
upon the blown -out end of the tube, and
allowing the edges of glass to fall
together over the metal by heating the
tube in the blowpipe flame.
In order that the gases under exami-
THE SPECIFIC GRAVITIES OF GASES. 123
nation should issue from the aperture e under precisely
the same conditions of pressure, a float 66, made as
light as possible, of thin glass, is placed in the tube a a.
This float carries at a small bead of black glass, to
which a thread of white glass is attached; and at ft and
ft are placed two other threads of black glass which,
like the black bead , serve as marks of level.
If the tube containing the gas to be examined, and
the glass float, be dipped so deep in mercury that the
level of the mercury outside , coincides with a mark y on
the tube, the float is not visible to a telescope directed
on to the mark y. The stop -cock c can now be opened,
and the gas thus allowed to escape through the aperture
e, so that the float 66 rises with the level of the mercury
inside the tube. During this time the experimenter must
observe the level of the mercury through the telescope,
and after a little time the white thread appears, giving
notice that before long the black bead will rise to the
level //. At the moment when the bead becomes visible
the observations of time must be made with a pendulum
vibrating half -seconds, previously verified by a chrono-
meter. These observations of time are concluded at the
instant the black thread ft appears in the field of view
of the telescope, the thread ft gives, as before, warning
as to the approach of the end of the experiment.
By means of these observations, the time of effusion
of a column of gas is obtained having a constant length of
from /3 to ft reckoning from y on the tube, and issuing
tinder pressures the sum of which remains always constant.
This time of effusion, determined for various gases, raised
to the square gives the relation of the specific gravities
of the gases.
124 METHODS OF DETERMINING
The arrangement represented in Fig. 41, serves to
hold the instrument. The tube is fastened to the arm b
which is moveable on the standard a a ; by means of this
Fig. 41.
arm the tube can be sunk into a hole in the block J,
until, when the stop-cock is open, the mercury completely
fills the instrument. As soon as the tube is filled with
mercury, it is raised out of the mercurial trough, and, as
the glass float is already contained in the tube, the gas
is allowed to enter in the usual manner from below. If
a large amount of gas is placed at the disposal of the
THE SPECIFIC GRAVITIES OF GASES.
125
experimenter, it is more convenient to remove the little
glass tube d, and to allow the gas to enter the instrument
from above and to expel the air by the lower end of the
tube which dips under the surface of the mercurial trough.
The arrival of the marks on the float above the level of
mercury is observed through the plate glass sides h h of
the trough. For the sake of greater accuracy it is ad-
viseable to take the mean of several series of observations.
It is scarcely necessary to mention that the gases must
be employed in the dry state, and that all oxidation of
the mercury, which would retard the motion of the float
must be most carefully avoided.
The following experiments show the degree of ac-
curacy which can be attained by this method. The first
column t contains the times of effusion of a volume of air,
the second column t the times of effusion of an equal vol-
ume of gas , the third and fourth columns the square of
these observed times, and the fifth column the specific
gravities calculated from these squares.
Air
Hydrogen
. t*
*i*
/,*
t
*i
t*
105.5
29.7
11130
882.09
0.0792
105.0
30.0
11025
900.00
0.0816
105.5
29.5
11130
870.25
0.0782
105.6
29.3
11151
858.48
0.0770
105.5
11130
126
SPECIFIC GRAVITY.
Air
Oxygen
t*
i 2
*, 2
t
h
t 2
102.5
108.5
10506
11772
1.1205
103.0
109.0
10609
11881
1.1199
102.8
108.5
10961
11772
1.1140
Air
Carbonic acid
*, 2
t
n
r!
102.7
127.0
10547
16129
1.5292
127.5
16257
1.5414
Air
t
Electrolytic
deton. gas
<i
t*
i 2
*. 2
t*
117.9
75.4
13900
568.52
0.4090
117.0
75.5
13689
570.03
0.4164
117.9
75.5
13900
570.03
0.4101
117.6
75.6
13830
571.54
0.4133
75.9
576.08
0.4166
Air
t
1 vol. CO
-f- 1vol. CO 2
*i
2
, 2
tS
t*
117.9
130.5
13900
17030
1.2251
127.0
16129
1.1603
130.5
17030
1.2251
SPECIFIC GRAVITY.
127
The mean specific gravities calculated from these
experiments are collected in the following table. The
first column contains the experimental results, the
second column the same values calculated from the
atomic weights.
Gases.
I.
II.
Difference.
Air . .
1.000
1 000
Carbonic acid . . . .
1 vol. CO + 1 vol. CO 2
1.535
1.203
1 118
1.520
1.244
1 106
-f- 0.015
0.041
_j_ o 012
Electrolytic deton. gas
Hydrogen ....
0.414
0.079
0.415
0.069
- 0.001
4- o.oio
It is seen that the agreement between the experimental
and calculated values is very close. For technical pur-
poses, as, for instance, the determination of the specific
gravity of coal gas, this method is peculiarly applicable
from its extreme simplicity.
128 LAWS OF THE ABSORPTION.
ABSORPTION OF GASES IN LIQUIDS.
(jraseous bodies are absorbed by liquids, on which
they exert no chemical action, in quantities dependant
upon
1st the essential nature of the gas and of the absorbing
liquid ;
2nd the temperature;
3rd the pressure, to which the gas is subjected.
The volume of gas, reduced to C. and O m 76 pres-
sure of mercury, which is absorbed by the unit volume
of a liquid, under the pressure of O m 76 of mercury, is
called the absorption-coefficient, or coefficient
of absorption.
The value of this absorption - coefficient in general
decreases with increase of temperature, in a ratio depen-
dant upon the chemical nature of the absorbed gas and
absorbing liquid. The values of the absorption - coeffi-
cients for varying temperatures can only be empirically
determined.
An exact relation is, however, found to exist between
OF GASES IN LIQUIDS. 129
the volumes of absorbed gas *, and the pressures, under
which the absorption takes place: The quantity of gas
absorbed varies directly as the pressure.
The coefficient of absorption of any gas is therefore
known, when the following quantities are given: 1st, the
volume V before the absorption, reduced to C. and obser-
ved under the pressure P\ 2nd, the volume Fi, remaining af-
ter the absorption, reduced to C. and standing under the
pressure PI ; and 3rd, the volume hi of the absorbing liquid.
The quantity of gas absorbed by this volume hi of
liquid under the pressure P l , is equal to the difference
between the volume of gas originally taken, and that re-
maining unabsorbed:
VP _ \\Pi
0.76 " 0.76 '
If the pressure during the absorption had not been
PI but 0.76, the amount of gas absorbed would have been
according to the above law,
VP
- F -
Hence it follows, that the coefficient of absorption,
i. e. the quantity of gas absorbed in the unit volume of
liquid under the pressure 0.76, is
When this coefficient a. is known, the quantity of gas
g absorbed in li volumes of liquid under a pressure P is
given by the equation :
* The expressions quantity of gas " or reduced volume " are
henceforward to be understood to signify the volume of gas,
reduced to C. and 0.7G pressure of mercury.
9
130 LAWS OF THE ABSORPTION
If two or more gases are mixed together, the ab-
sorption of the constituent parts is proportional to the
pressures, to which these parts are severally subjected.
Let the volumes v l v 2 v n , Fig. 42, of different gases, each
Fi s- 42 - under the pressure P, remain un-
mixed one above the other, sepa-
rated by the diaphragms ii, ^ij,
each of the gases exerting a pressure
P against the inclosing diaphragm;
withdraw the diaphragm and re-
move the resistance opposing the
action of the pressure, and the par-
ticles of v l will, in virtue of the
pressure P, penetrate into the ga-
ses 2 u B , which offer no resistance.
The motion of the particles of the gas v l ends with a
state of equilibrium , which ensues when the pressure
exerted by v^ has become equally great at every point of
the space v -j- v 2 -\- v, that is, when the gas v 1 has uni-
formly extended itself throughout this whole space. The
pressure on i^ is therefore, according to the law of Mariotte :
*>1 V 2
In like manner it is found, that the gases v 2 and v n ,
when equilibrium has ensued, are subject to a pressure of
- rJ*- P and - . '" , P.
Vl + V 2 -)- V n ^1+^2+ V n
From these pressures of the constituent parts the
total pressure of the mixture is found to be
p\ __ * p \
'
Vl + V 2 -f- V n V l -f- V 2 -|- V n ' V 1 -f- V 2 -\- V n
The quantity of each constituent gas absorbed, is pro-
portional to the pressure on that constituent part
OF GASES IN LIQUIDS. 131
^3 _ p.
+ J. ,
V * + V n
and these pressures may be distinguished as partial
pressures", in contradistinction to the ,,total pressures" of
the whole mixture.
If a mixture of gases , the constituents of which are
supposed not appreciably altered by absorption, consists
of two or more volumes of chemically different gases
v i V 2 v n > the amount of each gas dissolved in h volumes of
liquid under the pressure P, when a t 2 a n are the respec-
tive absorption -coefficients of the different gases at the
observed temperature, is of the first gas,
j 1l P Vi
0.71) (i ?1 +*,+,)''
of the second gas,
of the 7ith gas,
a n h P v n
0.76 (v, + v, + v n )
The unit volume of the absorbed gaseous mixture
therefore contains , of the first gas
?/! =
of the second
2 =
U
of the nth
If, on the contrary, the quantities of the separate ga-
ses ?/! u 2 . . . contained in the unit of absorbed gas are
known, the composition of the gas used for the absorp-
132 LAWS OF THE ABSORPTION
tion, supposing that its constituents remain in a constant
relation during the experiment, is found from the follow-
ing equations.
The unit of free gas contains of the first gaseous
constituent,
^+^+- -t
of the second
v. 2 =
i , U 2 U n
-- u. -4- . . . _) --
'
of the third
i_ , a. , i _-.
1 2
These formula} are only strictly true on the suppo-
sition, that the relation originally existing between the
volumes of the constituent gases is not appreciably dis-
turbed in consequence of the absorption; they are there-
fore, accurately speaking, only applicable in the case in
which a gaseous mixture of constant composition, either
infinitely large or continually renewed, acts upon a finite
volume of liquid. If the volume of liquid employed, is
appreciable compared with the volume of gas, the altera-
tion which the absorption causes in the composition of
the unabsorbed gas, must be brought into the calcula-
tion.
Let us next consider the alterations which a mix-
ture of two gases undergoes by absorption, supposing
that all the volumes of gas are reduced to C.
OF GASES IN LIQUIDS. 133
Let the total volume of gas under the pressure P be
V\ in the unit volume of this gas let there be v volumes
of the first gas, and i\ of the second. Let the absorption-
coefficient of the first gas at the observed temperature be
a, and that of the second 0, and the volume of absorbing
liquid h. Further, let the total volume of the gas remain-
ing after the absorption be V l under the pressure P l ;
and, lastly, let the unit volume of this residual gas con-
tain u volumes of the first, and w x volumes of the second gas.
The volume V contains v V volumes of the first gas
vVP
at the pressure P, or volumes at O m 76. This volume
is separated by absorption into two parts: the first part,
,c, remains behind after the absorption a free gas ; the
second, ^, is that absorbed by the w&kex^ The quantity
of this latter is determined by the law of absorption; the
unit of liquid absorbs the volume a under the pressure
O m 76 ; hence under the pressure PI , h volumes of water
will absorb
ah Pi
0.76 '
As, however, the first gas is expanded by mixing
V P
with the second from x to * /r , the quantity of gas ab-
sorbed by h is, by virtue of the partial pressure,
alix
Hence
or
vVP
ahx v V P
~'~ : ~~'
134 LAWS OF THE ABSORPTION
and by similar reasoning, the volume of the second gas is
0,6 (l + f J
Hence when
,,
we obtain
(AB l + A#) ~~ + y~
A n
^--y^nt ... (6)
It is clear that, vice versa, the unknown composition
of a gaseous mixture may be found from the change of
volume ensuing on absorption by a liquid. In this way
it is possible to analyse mixtures of gases by a purely
physical experiment, unassisted by chemical decomposi-
tion. Such absorptiometric determinations, as I term
them, are, under certain conditions, scarcely less correct
than a chemical analysis, and often much more simple
and convenient. Frequently, indeed, this mode of analysis
is of immense importance, as solving questions, which by
other methods are not determinable.
Let us next consider the case, in which two gases are
given whose relation to each other is to be determined
by an absorptiometric experiment.
Let # be the original volume of the first gas reduced
to the pressure 1 ;
Let #' be the volume of the same gas unabsorbed,
also reduced to the pressure 1 ;
Let v be the volume of the unabsorbed gaseous mix-
ture at the pressure P' ;
OF GASES IN LIQUIDS. 135
r'
The pressure of the unabsorbed gas 1 is then --T*/
1 {/
If the absorbed quantity of the gas 1 be reduced to this
pressure, the volume is ah: reduced to the pressure 1, it
is therefore:
17 *
and hence
or
ah
Hence the pressure of the unabsorbed gas 1 is
x
v' + a h
If y and y' represent the same values for the gas 2,
which x and x' did for the gas 1 , the pressure of the un-
absorbed gas 2 is
y
v' + flh'
As P' is the pressure of the mixture, we get
p.- __ _ i
~
ah v' + fih
If P is the pressure under which the mixture origi-
nally occupied the volume V, we have
PJL i _i_
V V
(also obtained when h = 0). We have then
1 - x J-
= ./ / " /
. _J i
- V p T
136 LAWS OF THE ABSORPTION
If we place
VP= w;
(P-f- ah) P* = A,
we obtain
x W B A
y = A - - W ' B '
or the volumes of the first and second gases in the unit
volume of the mixture are
~^~+~y == T~-^~B ' ~W ' ' ' ' (? )
y A W B
~aT+~y " ~A~- ^~B ' ~W '
For the case in which n gases are to be determined,
n equations are required, easily obtained by observing
for particular temperatures if, t- L ,t%,...,t n _ l , or for different
volumes of liquid A, A l7 A 2 , . . ., A n _i, the corresponding
gaseous volumes V, F x , F>, . . ., F w _ n at various pressures
P, PI , P>, . . ., P H _ r Thus for a mixture of three gases
whose volumes are x -f- y -)- z the following equations
are obtained :
_ i I __
^ ^ VP 9
j
i _ i_ i *
If we substitute , 6, c for the coefficients -r= in
the first equation, a 1? &j, c'j for 7^ - in the
(l/j -f-
second, and a. 2 , ^/ 25 z ^' or TTT i - 7 . in the third,
( V-2 -
we obtain:
it' ^i 6j C 2 U-2 GI +
b. 2 G 6' 2 + GI DI G
y B ac* 2 ac\ + ci]
z C ci LI a b<) + (-
+ f 5
6(2 GI Cl<2 G
y B ci Co ci GI | c
or
y _
B
X
A
z
+ B + C
C
x
The determination of the coefficients of absorption
is of the greatest importance in gasometric investigations.
The experiments are conducted in an absorptiometer, the
arrangement of which is seen in Fig. 43 (see p. 138).
The absorption - tube e, Fig. 43, divided into milli-
metres and calibrated, has a small iron band 6, Fig. 44,
furnished with a screw, luted on to its lower and open
end; this fits into another screw attached to the small
iron stand a a , Fig. 44. By this arrangement the open
end of the tube can be screwed down against a plate of
caoutchouc covering the bottom of the stand, and the
tube thus completely closed. On each side of the stand
are fixed two steel springs cc, which fit into two vertical
grooves in the inside of the wooden foot of the apparatus
/, Fig. 43, so that the little iron stand a a, Fig. 44, can be
raised or depressed, but not turned on its axis to the right
or left. The outer cylinder gg, Fig. 43, is not cemented
into the wooden foot /, or into the iron rim A, but the
screws ii press the ground -glass edges of the cylinder
against caoutchouc rings placed to receive them. The
tubes rr serve to pour in mercury, so that any desired
pressure is obtained in the absorption-tube by raising or
138 METHOD OF DETERMINING
Fig. 43.
44.
THE COEFFICIENTS OF ABSORPTION. 139
depressing the level of mercury in the inner glass cylin-
der. The temperature of the surrounding water is deter-
mined by the small thermometer k. The upper end of
the outer cylinder is closed by an iron lid having a
hinge at one side, and fastened clown by means of a nut
and screw attached to the iron rim /&, fitting into a small
slit p, in the side of the lid. In the inside of the lid there
is a raised rim of iron, over which a thick sheet of caout-
chouc is extended and fastened by a screwed ring s. This
distended caoutchouc serves as a spring against which
the top of the tube can be pressed, keeping it in a fixed
position during the violent agitation necessary during the
process of absorption.
The experiment itself is conducted in the following
manner: A volume of the gas to be examined is first
collected in the tube over mercury, and the usual pre-
cautions taken in reading off &c. , as in the processes of
gasometric analysis. A measured .volume of water per-
fectly free from air is next admitted under the mercury
into the tube, which is then screwed tightly against the
caoutchouc plate, and the tube thus closed, placed in the
cylinder gg containing some mercury, and over that a
quantity of water. As soon as the pressure within and
without has been equalised by slightly turning the tube,
it is again closed, and the whole apparatus rapidly agi-
tated for about a minute. This agitation with opening
and closing of the tube is continued many times, until no
further change of volume is perceptible. The obser-
vations necessary for the measurement and reduction of
the residual gas are then repeated. Besides the tempe-
rature t and the barometric pressure p, four readings
from the divided tube are required:
140 EXAMPLE OF THE CALCULATION.
1. The lower level of the mercury in the outer cylinder
at a.
2. The upper surface of mercury in the absorption-tube
at b.
3. The upper surface of water in the absorption -tube
. at c.
4. The upper surface of water in the outer cylinder at J.
The method of calculation is best explained by an
example. For this purpose, I select an experiment for
the determination of the absorption -coefficient of nitro-
gen for water at 19 C.
ELEMENTS OF THE CALCULATION..
1. Observations before the absorption.
Lower surface of mercury in outer cylinder . . . a = 423. G mm
Upper surface of mercury in absorption -tube * . . & 124.1
Barometric pressure p = 746.9
Temperature of the absorptiometer t 192 C.
Temperature of the barometer i 190
2. Observations after the absorption.
'mm
Lower surface of mercury in outer cylinder . * . . a t = 352. 2*
Upper surface of mercury in absorption -tube . . &j = 350.7
Upper surface of water in absorption - tube . . . c x = G5.5
Upper surface of water in outer cylinder . . . . d v = 8.0
Barometric pressure p l = 74G.3
Temperature of the absorptiometer . . . . . . t Y = 190 C.
Temperature of the barometer t l = 189
* In this first series of observations the absorptiometer contained
only mercury and no water.
NITROGEN IN WATER, HI
REDUCTION OF THESE ELEMENTS.
1. Before the absorption.
Surface of mercury at a = 423. G
Surface of mercury at & = 124.1
Column of mercury in the absorption - tube . . (a &) = 299.5
Ditto reduced to C n = 298.0 ,.
The barometric pressure (p 0.7469) reduced
to C TT, = 744.4
The pressure on mercury on the gas reduced
to C (TT I TI) = 445.9
Tension of aqueous vapour at 192 C. to be sub-
tracted = 1G.G
Pressure of the dry nitrogen P = 429.3
The volume of gas corrected from the calibra-
tion read off at 6 = 124.1 at 192 C. . . . =34.90
Ditto reduced to C F= 82.608
2. After the absorption.
Barometric pressure p, = 74G.3 reduced to C. ef = 743.8 n "
Surface of mercury at a t = 352.2
Surface of mercury at b r =. 350 7
Column of mercury in tube at 190 JD. . . . (a t fti) = 1.5
Ditto at C tf , = 1.5
Lower surface of water in absorption -tube at 2^=350.7
Upper surface of water in absorption - tube at c t = G5.5
Column of water in the absorption -tube . (?> t c,) = tt7 = 285.2
Lower surface of water in outer cylinder ... a^ = 352.2
Upper surface of water in outer cylinder ... d l = 8.0
Column of water in outer cylinder . . . (a, d l ')-=zw l =344.2
Column of water (u\ w) acting in opposition
to the barometer = 59.0
Ditto reduced to pressure of mercury .... q = 4.4
The pressure reduced to C (f ^ 9) = 746.8
Tension of aqueous vapour at 19 C. to be sub-
tracted = 1G.3
Pressure of the unabsorbed nitrogen .... PI = 730.5 ,,
142
EXAMPLE OF CALCULATION.
The residual volume of gas corrected from cali-
bration read off at division c x = 65.5 .... = 17.G7 mm
Ditto reduced to C . F, == 16.52
The corresponding volume to division 6 X = 350.7 = 200.04
Volume of absorbing liquid ^ = 182.37
The value of the absorption -coefficient, as obtained
from these numbers by equation No. 1, is
= ^- ^- K = 0.01448.
The accuracy of these determinations depends in a
great measure upon the water employed being perfectly
free from air. This is best accomplished by boiling the
water briskly for several hours, and then causing it to
pass whilst still boiling into a flask , the neck of which
has been drawn out to a fine point before the blowpipe
(see Fig. 45). The water is then again boiled in this
Fig. 45.
WATER FREED FROM AIR. 143
flask for half an hour , and the end of the tuhe hermeti-
cally sealed, access of air being prevented during the
closing by pressing a caoutchouc tube a attached to the
extremity. When the water thus freed from air (which
should strike against the glass like a water-hammer), is
required for experiment, the closed end of the neck is
moistened with solution of corrosive sublimate, and broken
under mercury, and the water admitted directly into the
absorption -tube. Before transferring the water into the
tube, one must be convinced that no bubble of air has
appeared in the flask, which would show imperfect
boiling.
The following coefficients of absorption were deter-
mined according to this method, partly by myself and
partly by Messrs. Carius, Pauli, and Schb'nfeld in my
laboratory. The alcohol employed for the experiments
had a specific gravity of 0.792 at 20 C. The corrections
for the tension of the vapour of alkohol were made from
the experiments of Muncke.
Table III of the appendix contains these tensions
calculated from the far more accurate experiments of
Regnault.
144 NITROGEN IN WATER.
No. 1. NITROGEN IN WATER.
The gas was prepared by passing dry air, freed from
carbonic acid and ammonia, over red-hot copper turnings.
No. of the
C.
Coefficient
Coefficient
from formula
Difference.
experiment.
found.
9.
1
4.0
0.01843
0.01837
O.OOOOG
2
G.2
0.01751
0.01737
0.00014
3
12.G
0.01520
0.01533
-f- 0.00013
4
17.7
0.0143G
0.01430
O.OOOOG
5
23.7
0.01392
0.01384
0.00008
|
By combination of the experiments 1, 2, 3; 2, 3, 4;
and 3, 4, 5, we obtain the interpolation formula
c = 0.020346 0.00053887 -f- 0.000011156 *? . (9)
No. 2. NITROGEN IN ALCOHOL.
No. of the
C.
Coefficient
Coefficient
from formula
Difference.
experiment.
found.
10.
1
1.9
0.12561
0.12567
-j- O.OOOOG
2
6.3
0.12384
0.12393
-f- 0.00009
3
11.2
0.12241
0.12241
0.00000
4
14.G
0.12148
0.12152
-}- 0.00004
5
19.0
0.12053
0.12056
-f- 0.00003
G
23.8
0.11973
0.11979
-f O.OOOOG
By combination of experiments 1, 2; 3,4 and 5, 6,
we obtain the interpolation formula
c = 0.126338 0.000418 1 -f 0.0000060 /? . . (10)
HYDROGEN IN WATER.
145
No. 3. HYDROGEN IN WATER.
This gas was prepared from pure zinc and dilute
sulphuric acid.
No. of the
experiment.
C.
Coefficient
found.
Difference
from mean
value.
1
4.0
0.0185
0.0008
2
3
7.0
9.G
0.0205
0.019G
-|- 0.0012
-f o.oooi^
4
12.8
0.018G
0.0007
5
15.5
0.0197
-|- 0.0003
G
18.8
0.0188
0.0005
7
23.G
0.0194
-j- 0.0001
From these experiments it is seen that the mean
coefficient of absorption 0.0193 of hydrogen is constant
for temperatures between and 20 C.
No. 4. HYDROGEN IN ALCOHOL.
No. of the
experiment.
C.
Coefficient
found.
Coefficient
from formula
11.
Difference.
1
1.0
0.06916
0.06910
0.00006
2
5.0
0.06847
0.06853
-|- 0.00006
3
11.4
0.06765
0.06769
+ 0.00004
4
14.4
0.06726
0.06732
-f 0.00006
5
19.9
O.OGGG8
0.06669
-f 0.00001
6
23.7
0.06633
0.06629
- 0.00004
By combination of the experiments 1, 2, 3 ; 2, 3, 4, 5
and 4, 5, 6 the following interpolation formula is obtained:
c = 0.06925 0.0001487 / -f- 0.000001 <* . . (11)
10
14G
ABSORPTION OF GASES IN LIQUIDS.
No. 5. METHYL GAS IN WATER.
For these experiments a quantity of the same sethyl
gas was employed, which Professor Frankland prepared
in my laboratory some years ago , and of which he gave
the analysis in his researches on the organic radicals.
No. of the
experiment.
C.
Coefficient
found.
Coefficient
from formula
12.
Difference.
1
5.8
0.02637
0.02G2G
4- 0.0011
2
8.7
0.02393
0.02428
0.0035
3
4
5
14.0
17.2
21.8
0.02199
0.02103
0.0202G
0.02175
0.02092
0.020G1
-f- 0.0024
-j- 0.0011
0.0035
By combination of the experiments 1, 2, 3; 2, 3, 4,
and 3, 4, 5, the following interpolation formula is found:
c = 0.031474 0.0010449 t -f- 0.000025066/2 . (12)
No. 6. CARBONIC OXIDE IN WATER.
The gas was prepared by heating sulphuric acid with
pure formiate of magnesia ; treatment with a potash-ball
showed that the gas was perfectly pure.
No. of the
experiment.
C.
Coefficient
found.
Coefficient
from formula
13.
Difference.
1
5.8
0.028G3G
0.028691
-j- 0.000055
2
8.6
0.027125
0.027069
0.000056
3
9.0
0.02G855
0.026857
-\- 0.000002
4
17.4
0.023854
0.023642
- 0.000212
5
18.4
G.023147
0.023414
-\- 0.000267
6
22.0
0.022907
0.022863 '
0.000044
CARBONIC OXIDE IN ALCOHOL. 147
If the mean values from 1, 2, 3, from 2, 3, 4, 5, and
from 4, 5, 6, be taken for the calculation of the constants,
we obtain the following formula :
c = 0.032874 0.00081632 1 + 0.000016421 t* . (13)
No. 7. CARBONIC OXIDE IN ALCOHOL.
No. of the
C.
Coefficient
Variation
from mean
experiment.
found.
value.
1
2.0
0.2035G
0.00087
2
7.0
0.20526
-f 0.00083
3
12.9
0.2041G
0.00027
4
1G.2
0.205GG
-f 0.00123
5
12.9
0.20341
0.00102
G
24.0
0.20452 -f- 0.00009
The coefficient of carbonic oxide and alcohol remains
the same between and 25 C.; the mean value is
0.20443.
No. 8. LIGHT CARBURETTED-HYDROGEN IN WATER.
I have used for this determination a gas, preserved
in hermetically closed tubes, which is found in the mud-
volcanoes of Bulganak in the Crimea, where it occurs un-
der similar circumstances as at Baku on the Caspian Sea.
This gas was employed because it appeared from my ex-
periments to be the purest which occurs naturally. By
treatment with a potash -ball, it was freed from a trace
of carbonic acid, and it contained as the following ana-
lysis shows, neither nitrogen, oxygen, nor defiant gas:
10*
148
MARSH GAS IN WATER.
Vol.
C.
Press,
in me-
tres.
Vol. at
C. and
l m press.
Original volume of gas
After admission af air
127. G
499-0
537.4
495.4
4GG.2
4.8
4.8
4.8
4.5
4.6
0.159G
5151
0.5500
0.5115
0.4994
20.01
252.60
290.47
249.29
228.97
After admission of oxygen ....
After the explosion
After absorption of carbonic acid .
After addition of hydrogen ....
After the explosion
G09.3
478.8
Foui
20
4.3
4.3
ad. Gal
01 2
82 2
18 4
18 4
O.G284
0.5105
lulated.
0.45
0.45
0.90
0.90
376.95
240.64
Gas employed
Carbonic acid formed
Contraction
. . 20.
. . 41.
. . 41.
Oxygen consumed . .
This gas gives the following absorptiometric values:
No. of the
experiment.
C.
Coefficient
found.
Coefficient
from formula
14.
Difference.
1
6.2
0.04742
0.04757
0.00015
*2
9.4
0.04451
0.04430
-f- 0.00021
3
12.5
0.04126
0.04134
0.00008
4
18.7
0.03586
0.03600
0.00014
5
25.6
0.03121
0.03100
+ 0.00021
The mean from 1, 2, 3, from 2, 3, 4, and from 3,4,5,
gives the interpolation formula
c = 0.05449 0.0011807 / -|- 0.000010278 1* . (14)
MARSH GAS IN ALCOHOL.
149
No. 9.
LIGHT CARBURETTED- HYDROGEN IN ALCOHOL.
The gas was prepared by heating acetate of potash
with hydrate of potash, and from the following analysis
is seen to be pure.
Vol.
Temp.
Press,
in me-
tres.
Vol. at
C. and
l m press.
Original volume of gas
75.2
5.0
0.2983
22.32
After addition of air
352.2
5.0
0.5736
201.04
Alter addition of oxygen
399.3
5.3
0.6183
242.19
After the explosion
352.2
5.2
0.5728
197.97
Alter absorption of carbonic acid .
325.0
5.6
0.5538
176.37
Found. Calculated.
Cras employed 22
32 22.11
Carbonic acid produced . 22.25 22.11
Contraction 44.22 44.22
Oxygen employed .... 44.22 44.22
Absorption gave the following elements:
No. of the
C.
Coefficient
Coefficient
from formula
Difference.
experiment.
found.
15.
1
2.0
0.51721
0.51691
0.00030
2
6.4
0.50382
0.50483
-|- 0.00101
3
11.0
0.49264
0.49278
-|- 0.00014
4
15.0
0.48255
0.48280
-f 0.00025
5
19.0
0.47290
0.47327
-|-. 0.00037
6
23.5
0.46290
0.46309
-f 0.00019
By combination of experiments 1, 2, 3 ; 2, 3, 4, 5, and
4, 5, 6, the following interpolation formula is obtained:
c = 0.522586 0.0028655 1 + 0.0000142 f> . (15)
150 METHYL GAS IN WATER.
No. 10. METHYL GAS IN WATER.
For this experiment, a specimen of methyl gas, sealed
up in a glass tube, was used, which Professor Frankland
prepared from iodide of methyl, and analysed some years
ago at Marburg:
No. of the
c.
Coefficient
Coefficient
from formula
Difference.
experiment.
found.
16.
1
4.6
0.072884
0.073084
0.000200
2
7.8
0.064732
0.064839
0.000107
3
12.1
0.055788
0.055703
-}- 0.000085
4
15.2
0.050722
0.050500
-}- 0.000222
5
19.8
0.045715
0.044915
-}- 0.000800
6
24.2
0.040817
0.041960
0.001143
If the arithmetical mean of 1, 2, 3, 4, of 3, 4, 5, and
4, 5, 6, are used for the equations for the interpolation
formula, we get:
c = 0.0871 0.0033242* -f- 0.0000603 * . (16)
No. 11. OLEFIANT GAS IN WATER.
The gas was prepared with the well known pre-
cautions from alcohol and sulphuric acid. To free it
from the vapour of alcohol and aether, and from traces
of other hydrocarbons polymeric with elayl, a ball of
coke, saturated with concentrated, but not fuming sul-
phuric acid, was placed in the gas until nearly the half
of it was absorbed; a ball of potash was afterwards
introduced, and left in contact with the gas for some
OLEFIANT GAS IN WATER.
151
time. The following analysis showed the perfect purity
of the gas :
Pressure
Vol. at
Vol. i C.
C. and
in metres.
l m press.
Original volume of gas . . .
36.7
12.0
0.2443
8.64
After addition of air . . . .
311.2
12.0
0.5183
154.52
After addition of oxygen . .
339.8
12.5
0.5462
177.48
After the explosion ....
318.0
12.0
0.5261
160.26
After absorption of carbon, acid
290.1
11.2
0.5130
142.96
Found. Calculated.
Gas employed 8.64 8.61
Carbonic acid produced . 17.31 17.22
Contraction 17.22 17.22
Oxygen consumed . . . 25.91 25.83
Absorptiometric experiment gave:
No. of the
n c.
Coefficient
Coefficient
from formula
Difference.
experiment.
found.
17.
i
1
4.6
0.21870
0.21824
-|- 0.00046
2
9.6
0.18398
0.18592
0.00194
3
14.0
0.16673
0.16525
-1- 0.00148
4
18.0
0.15324
0.15278
-}- 0.00046
5
20.6
0.14597
0.14791
0.00194
The following interpolation formula is obtained from
the mean of 1, 2, 3, and 2, 3, 4, and 3, 4, 5:
c = 0.25629 0.00913631 1 + 0.000188108 **. (17)
152 CARBONIC ACID IN WATER.
No. 12. OLEFIANT GAS IN ALCOHOL.
No. of the
c.
Coefficient
Coefficient
from formula
Difference.
experiment.
found.
18.
1
0.8
3.5344
3.5484
-f- 0.0140
2
5.4
3.3109
3.3033
0.0076
3
10.9
3.0431
3.0469
-f- 0.0038
4
15.4
28G45
2.8679
-f- 0.0034
5
19.3
2.7302
2.7348
+ 0.0046
G
23.8
2.6048
2.6072
4- 0.0024
The following interpolation formula is obtained from
the mean of 1, 2, and 3, 4, and 5, 6:
c = 3.59498 0.057716* + 0.0006812*2. . (18)
No. 13. CARBONIC ACID IN WATER.
This gas was prepared by the action of strong sul-
phuric acid upon chalk, a few drops of water being
added to the mixture. The gas, thus steadily evolving,
was washed by being passed through boiled water. The
experiment gave :
No. of the
C.
Coefficient
Coefficient
from formula
Difference.
experiment.
found.
19.
1
4.4
1.4698
1.4584
-f 0.0114
2
8.4
1.2426
1.2607
0.0181
3
13.8
1.0654
1.0385
-f- 0.0269
4
16.6
0.9692
0.9610
-f 0.0082
5
19.1
0.8963
0.9134
- 0.0171
6
22.4
0.8642
0.8825
0.0183
OXYGEN IN WATER.
153
The three equations formed from the mean of 1, 2,
3, 4, of 2, 3, 4, and of 3, 4, 5, 6, give the interpolation
formula :
c = 1.7967 0.07761 1 + 0.0016424?2. . (19)
No. 14. CARBONIC ACID IN ALCOHOL.
No. of the
C.
Coefficient
Coefficient
from formula
Difference.
experiment.
found.
20.
1
3.2
4.0442
4.0416
0.0026
2
6.8
...7374
3.7480
-f- 0.0106
3
10.4
3.4875
3.4866
0.0009
4
14.2
3.2357
3.2457
-f 0.0100
5
18.0
3.0391
3.0402
-f 0.0011
6
22.6
2.8277
2.8396
-|- 0.0119
The mean from 1, 2; 3, 4, and 5, 6 gives the inter-
polation formula:
c = 4.32955 0.09395 1 + 0.00124*2. . (20)
No. 15. OXYGEN IN WATER.
Oxygen gas, prepared in the usual manner from
chlorate of potash, gave the following results:
No. of the
c.
Coefficient.
experiment.
1
6.0
0.04609
2
8.3
0.04186
3
11.6
0.03921
4
18.1
0.03715
5
22.8
0.03415
154
OXYGEN IN WATER.
During the agitation in the absorptiometer, the water
became turbid owing to the formation of a black powder,
and it was supposed that the metals dissolved in the
mercury had been oxidised at the expense of the oxygen
in the water, and hence too large a coefficient obtained.
The mercury employed, was therefore freed from all
foreign metals, as perfectly as could be effected by
several digestions with concentrated nitric acid. The
experiment conducted with the purified mercury gave the
following results:
No. of the
C.
Coefficient.
Difference.
experiment.
1
19.4
0.03109
-}- 0.00090
2
19.G
0.03199
-f- 0.00003
3
19.4
0.03202
-j- 0.00052
4
19.5
0.03254
0.00009
5
19.5
0.03245
-f 0.00047
G
19.5
0.03292
-f- 0.00221
7
19.0
0.03513
0.00057
8
19.0
0.0345G
The experiment gave therefore, rather a smaller
coefficient. In spite, however, of the most careful pu-
rification, the mercury always caused a black turbidity
in the water, which perceptibly increased with agitation.
This circumstance, together with the fact that the coef-
ficients determined one after the other in the same liquid,
and at the same temperature, always regularly increased,
showed that this method was not to be relied upon
for exact results. I have, therefore, preferred to de-
INDIRECT METHOD. 155
termine the coefficient of oxygen in water by an indirect
method.
If atmospheric air, perfectly free from carbonic acid
and ammonia, be passed into boiled water, the amount
of oxygen F absorbed, and the amount of nitrogen V
absorbed, is found from the following equations (No. 3)
which we have already deduced :
aPOV\ V fiPNV l
~ 0.76 (N+0) ' ~ 0.76 (N+ 0)'
The first of these equations divided by the second gives
NV
ov p
N
As the composition of the air, i. e. the proportion y , as
well as the absorption -coefficient /3 of nitrogen is known,
Y
we only require to determine the proportion -=pr , or the
composition of the air dissolved in the water, in order
to calculate a, or the absorption -co efficient of oxygen.
The following experiments give the elements required
for this calculation. Atmospheric air carefully freed
from carbonic acid, and ammonia, was passed in a strong
current for half a day through the water, previously well
boiled, and kept at a constant temperature by immersion
in a water bath. The purification of the water must be
conducted with the greatest care. It must not be distilled
from a vessel previously used for any organic preparation,
as the slightest trace of volatile organic matter is suf-
ficient to convert a part of the oxygen into carbonic
acid. In order , therefore , to test the correctness of the
determination, it is adviseable to prove the absence of
carbonic acid in the air boiled out from the water by
special experiment.
15G
AIR IN WATER.
The gases dissolved in this water were collected by
a method which I employed in my investigations upon
the gases of the Icelandic springs , and more fully de-
scribed by Professor Baumert in his excellent research
on the respiration of the Cobitis fossilis.
Air from water saturated at 1 C.
Pressure
Vol. at
Vol.
C.
C. and
in metres.
l m press.
Volume of gas employed
216.85
0.2G44
9.7
55.374
-\- hydrogen . . .
37G.1G
0.4170
9.8
151.414
After the explosion
289.83
0.3340
9.9
93.420
Oxygen
Nitrogen
34.91
G5.09
100.00
Air from water saturated at 13 C.
Pressure
Vol. at
Vol.
C.
0C. and
in metres.
l m press.
Volume of gas employed
1G5.99
0.2198
9.0
53.324
-}- hydrogen . . .
346.28
0.3914
9.5
130.994
After the explosion
288.78
0.3371
9.2
94.180
Oxygen
Nitrogen
34.73
65.27
100.00
AIR IN WATER.
Air from water saturated at 23 C.
157
Pressure
Vol. at
Vol.
C.
0C. and
in metres.
l m press.
Volume of gas employed
206.67
0.2577
9.3
51.497
-}- hydrogen . . .
400.29
0.4437
9.2
171.828
After the explosion .
323.95
0.374G
8.7
117.608
Oxygen
Nitrogen
35.08
64.92
100.00
From these experiments, it is clear that the com-
position of the air dissolved in water at various tem-
peratures is always constant. The mean composition is:
Oxygen . ." . 34.91 = V
Nitrogen . . 65.09 = V
100.00
Thus we see, that the curve which represents the
increase of the absorption -coefficient of oxygen for de-
creasing temperatures is parallel to the corresponding
curve for nitrogen.
If we take the following as the true composition of
atmospheric air,
Oxygen . .. , 0.2096 = O
^ _ J_ Nitrogen . . 0.7904 N
1.0000
and if we substitute the values of PI, P, 0, and N in the
preeceding equation, we obtain, when represents the
absorption -coefficient of nitrogen, the value of the coef-
ficient of oxygen from the formula :
a = 2.0225 ft (21)
158 OXYGEN IN ALCOHOL.
No. 16. OXYGEN IN ALCOHOL.
As the oxygen which dissolved in alcohol scarcely
oxidises the metals contained in solution in the mercury,
Dr. Carius has determined the absorption -coefficients in
the usual manner with the absorptiometer.
No. of the
C.
Coefficient
Variation
from mean
experiment.
found.
value.
1
1.0
0.28389
0.00008
2
4.5
0.28588
-f 0.00191
3
9.8
0.28439
+- 0.00042
4
14.2
0.28122
0.00275
5
18.8
0.28373
- 0.00024
G
23.1
0.284G9
-f- 0.00072
Hence it is seen that the coefficients of absorption of
oxygen in alcohol are constant for temperatures between
and 24.
No. 17. NITROUS OXIDE IN WATER.
The gas was prepared from pure nitrate of ammonia.
No. of the
C.
Coefficient
Coefficient
from formula
Difference.
experiment.
found.
22.
1
2.5
1.1942
1.1962
-f- 0.0020
2
8.2
0.9700
0.9791
-f 0.0091
3
12.0
0.8432
0.8588
-f- 0.015G
4
1G.2
0.7477
0.7489
-|- 0.0012
5
20.0
O.G744
O.G700
- 0.0044
G
24.0
O.G024
O.G082
-j- 0.0058
NITROUS OXIDE IN ALCOHOL.
159
From the mean of 1, 2; 3,4, and 5, 6, the following
interpolation formula is obtained:
e = 1.30521 0.045362 * + 0.0006843 /. . (22)
No. 18. NITROUS OXIDE IN ALCOHOL.
No. of the
experiment.
c.
Coefficient
found.
Coefficient
from formula
23.
Difference.
1
2.3
4.0262
4.0207
0.0055
2
7.0
3.70G9
3.7192
-f 0.0123
3
ll.G
3.4219
3.4501
-f- 0.0282
4
18.2
3.1105
3.1092
- 0.0013
5
23.0
; 3.88G1
,8.8944
-f- 0.0083
The mean of experiments 1, 2 ; 2, 3, 4, and 4, 5, give
the interpolation formula:
c = 4.17805 0.069816 t + 0.000609 #*. . (23)
No. 19. NITRIC OXIDE IN ALCOHOL.
In order to obtain pure nitric oxide, this gas evolved
from copper and nitric acid, is led into a concentrated
solution of protosulphate of iron. The solution thus
obtained, when freshly prepared, and sufficiently con-
centrated, gives on heating, a gas perfectly free from
nitrous oxide and nitrogen, particularly if only the first
portions of gas are collected.
160
SULPHURETTED-HYDROGEN IN ALCOHOL.
No. of the
c.
Coefficient
Coefficient
from formula
Difference.
experiment.
found.
24.
1
2.0
0.30895
0.30928
-j- 0.00033
2
G.O
0.29G84
0.29G90
-f O.OOOOG
3
11.8
0.28162
0.28174
-f- 0.00012
4
1G.O
0.27250
0.27281
-f- 0.00031
5
20.0
0.2G573
0.2G592
-|- 0.00019
6
24.2
0.2G014
0.2G038
- 0.00024
From experiments 1, 2; 3, 4, and 5, 6, we obtain the
interpolation formula :
c = 0.31606 0.003487 1 + 0.000049 t*. . (24)
No. 20. SULPHURETTED -HYDROGEN IN ALCOHOL.
The absorptiometer cannot be used for the deter-
mination of the absorption -co efficients of those gases
which act upon mercury, nor of those which are extremely
soluble in water. In the case of sulphuretted -hydrogen,
which in presence of alcohol is decomposed by mercury,
another method must be had recourse to. The simplest
plan is to saturate the alcohol, at a constant tem-
perature, and under a known pressure, with sulphuretted-
hydrogen, and to determine the absorbed gas by che-
mical means. This saturation is best effected in the
apparatus Fig. 46, employed by Messrs. Schonfeld and
Carius in the determination of the following coefficients
of absorption.
The flask a a, containing the boiled-out alcohol which
is to be saturated, is closed by an air-tight cork with
four holes bored through it. In the first hole is placed
SULPHURETTED HYDROGEN IN ALCOHOL.
161
the small thermometer 6, dipping into the liquid; the
second hole contains the glass delivery tube c reaching
to the bottom of the flask ; the third is filled by a short
Fig. 46.
ji o
exit tube <7, through which the excess of gas escapes;
and the fourth contains a syphon -tube e dipping to the
bottom of the liquid. A rapid stream of sulphuretted-
hydrogen gas, prepared from sulphide of iron and sul-
phuric acid, and well washed, is passed for two hours
through the liquid from the delivery tube c, whilst the
whole apparatus is kept at a constant temperature by
immersion in a water -bath. After the current of gas
has passed for this period through the liquid, we may
presume that the point of saturation has been reached.
11
1G2 CHEMICAL METHOD.
The little caoutchouc tube on the end of the tube t/, is
next closed by a glass rod, whilst the evolution of gas
still continues; the slight increase of pressure ensuing
from this closing is sufficient to drive out the saturated
liquid by the syphon e. This stream of saturated alcohol
is allowed to flow on to the bottom of a small stoppered
bottle, so as gradually to fill the bottle, and to run over
the neck, in order to expel the portions of liquid which
have been in contact with the air, by those which flow
directly from the saturating flask. The small measure
is then quickly closed by its stopper, and after removing
the alcohol which remains on the outside, the saturated
liquid is emptied into a solution of chloride of copper,
SULPHURETTED -HYDROGEN IN WATER.
163
in which the sulphur of the precipitated sulphide is
estimated in the usual manner as sulphate of barium.
Let A represent the quantity of sulphate of barium found,
h the volume of the measure in cubic - centimetres , P the
barometric pressure under which the saturation took place,
and s the specific gravity of sulphuretted -hydrogen, we
obtain the value of the coefficient of absorption from the
following formula, the derivation of which is simple
enough:
(HS). 773. 0.76
a = A
(BaS0 4 ).5.P./i
Experiments carried on in this manner, gave the
following values for the absorption - coefficients of sul-
phuretted-hydrogen in alcohol:
No. of the
C.
Coefficient
Coefficient
from formula
Difference.
experiment.
found.
25.
1
1.0
17.367
17.242
0.125
2
4.0
15.198
15.373
-|- 0.17.-)
3
7.5
13.246
13.343
-|- 0.097
4
10.6
11.446
11.680
-}- 0.234
5
17.6
8.225
8.393 .
-f 0.168
G
22.0
6.624
6.659
-|- 0.035
From the mean of 1, 2, 3; 2, 3, 4, 5, and 4, 5, 6, the
following interpolation formula is obtained:
c = 17.891 0.65598 / + 0.00661 /. . . (25)
No. 21. SULPHURETTED -HYDROGEN IN WATER.
Experiments conducted in a similar manner to those
just described, gave the following results:
11*
164
SULPHUROUS ACID IN ALCOHOL.
No. of the
c.
Coefficient
Coefficient
from formula
Difference.
experiment.
found.
26..
1
2.0
4.2373
4.2053
0.0320
2
9.8
3.5446
3.6006
-f- 0.0560
3
14.G
3.2651
3.2599
0.0052
4
19.0
2.9050
2.9687
-f 0.0637
5
23.0
2.7415
2.7215
0.0200
a
27.8
2.3735
2.4470
-f- 0.0735
7
35.G
1.9972
2.0521
-f 0.0549
8
43.3
1.7142
1.7244
-|- 0.0102
The mean of experiments 1, 2, 3, 4; 2, 3, 4, 5, 6, 7,
and 5, 6, 7, 8, give the interpolation formula:
c = 4.3706 0.083687 1 + 0.0005213 t*. . (26)
No. 22. SULPHUROUS ACID IN ALCOHOL.
The pure alcohol of spec. grav. 0,792 used in these
experiments, was saturated, in a similar apparatus to
that described under sulphuretted -hydrogen, with pure
sulphurous acid, prepared from pure sulphuric acid, and
copper turnings, and carefully washed before saturation.
In order to determine the weight of sulphurous acid in
the saturated liquid, a measured volume was diluted with
so much boiled water, that 1000 parts of the mixture
contained less than 4 parts of the acid, and in this diluted
solution the sulphurous acid was estimated by the iodine-
volumetric method.
If the weight of an absorbed gas only amounts to
a small fraction of that of the absorbing liquid, we may
suppose, without any apparent error, that the volume of
ALTERATION OF SPECIFIC GRAVITY. 165
the liquid before, and after the saturation, has not
altered. This is, however, not allowable when so
much gas is absorbed, that the specific gravity of the
liquid is perceptibly changed. In this case the specific
gravities corresponding to the various degrees of sa-
turation must be determined, and from these and the
volume of the saturated solution, the volume must be
calculated which the liquid would have possessed before
it took up the gas.
Let his suppose that experiment showed that p gram-
mes of sulphurous acid was contained in V volumes of
alcohol , saturated at C., and under a pressure equal to
P\ and let the specific gravity of gaseous sulphurous acid
be represented by s, that of the saturated alcohol by s t ,
that of the pure alcohol before saturation by s 2 , we shall
then see that the absorption-coefficients, that is, the volume
of gas which is absorbed at *, and 0.76 pressure by the
unit volume of pure alcohol, is found from the following
considerations. The measured volume V of saturated
alcohol weighs Vsi, the pure alcohol which is contained
in this weight combined with sulphurous acid is therefore
(Vst p), and occupies the volume i-^ . But this
^2
volume has absorbed S- volumes of sulphurous acid ;
s
hence, 1 cbc. alcohol absorbs at P pressure and t tem-
perature of saturation, - 7 = '* ' ' cbc. of the gas.
(Fa, p)s
Hence the coefficient of absorption c, or the volume of
sulphurous acid absorbed by one volume of pure alcohol
at the temperature of saturation ?, and under the pres-
sure 0.76, hence is
1GG
ALTERATION OF SPECIFIC GRAVITY.
0.76 . 773 . p . s 2
c =
(27)
P(V Sl p)s
In order to calculate the value of c, the specific
gravities of the various saturated volumes of alcohol must
be determined. The following experiments served for
these determinations:
No. of the
experira.
Temp,
of the
saturation
C.
Spec. grav.
of solution
obtained.
Mean
*i-
Spec,
gray,
according
to formula
28.
Difference.
1
4.0
1.0GG4
1.0580
1.0G22
1.0G71
-f- 0.0049
2
11.6
0.984G
0.9914
0.9880
0.990G
-j- 0.002G
3
16.0
0.9490
0.95G4
0.9527
0.9597
-f- 0.0070
4
( 0.9370
20.1
/ 9434
0.9402
0.9400
0.0002
5
( 0.9242
23.5
/ 0.9322
1
0.9282
0.9302
-}- 0.0020
The mean from 1, 2; 2, 3, 4, and 4, 5, gives the
following interpolation formula:
c = 1.11937 0.014091 1 + 0.000257 t\ . (28)
By means of this formula the following table was'
calculated:
SULPHUROUS ACID IN ALCOHOL.
167
Temp,
of
saturation
HX
Specific
gravity.
Difference.
Temp,
of
saturation
Specific
gravity.
Difference.
o
1.1194
13
0.9796
0.0077
0.0139
0.0071
i
1.1055
14
0.9725
0.0133
0.0067
2
1.0922
15
0.9658
0.0128
0.0061
3
1.0794
16
0.9597
0.0123
0.0056
4
1.0671
17
0.9541
0.0118
0.0051
5
1.0553
18
0.9490
0.0112
0.0046
6
1.0441
19
0.9444
0.0108
0.0040
7
1.0333
20
0.9404
0.0102
0.0036
8
1.0231
21
0.9368
0.0097
0.0030
9
1.0134
22
0.9338
0.0092
0.0026
10
1.0042
23
0.9312
0.0087
0.0020
11
0.9955
0.0082
24
0.9292
0.0015
12
0.9873
25 0.9277
From this table are obtained the required values of
The other experimental data are found subjoined:
No. of the
experiment.
t
c.
P
P
*
1
3.2
0.7576
2.1677
1.0769
2
5.8
0.7458
1.9432
1.0463 j
3
11.0
0.7566
1.5663
0.9955 f
I
v ^^ 400
4
14.0
0.7510
1.3678
0.9725 ^
4 = 0.792
5
17.0
0.7558
1.2259
0.9541 j
6
20.0
0.7438
1.0920
0.9404 \
7
24.4
0.7536
0.9698
0.9286 '
By substituting these quantities in the preceeding
formula (No. 27), we obtain the following values for
1G8
SULPHUROUS ACID IN WATER.
the absorption - coefficients of sulphurous acid in al-
cohol.
No. of the
Coefficient
Coefficient
from formula
Difference.
experiment.
found.
29.
1
3.2
276.62
277.57
0.95
2
5.8
240.72
240.81
+ 0.09
3
11.0
177.84
179.91
2.07
4
14.0
149.29
152.45
- 3.16
5
17.0
130.12
130.61
- 0.49
6
20.0
114.48
114.38
H- 0.10
7
24.4
97.54
100.75
3.21
The interpolation formula for these experiments is
calculated from the mean of 1, 2; 3, 4, 5, and 6, 7:
c = 328.62 -16.95 t + 0.3119 1\ " . (29)
No. 23. SULPHUKOUS ACID IN WATp]R.
Experiments made in a like manner with water in-
stead of alcohol, gave the following results:
No. of the
Coefficient
Coefficient
from formula
Difference.
experiment.
found.
30.
1
4.0
68.64
69.89
-\- 1.25
2
10.0
55.79
56.65
-}- 0.86
3
15.6
46.30
46.25
0.05
4
21.0
37.02
37.97
-|- 0.95
5
26.0
32.13
31.58
0.55
From the mean of 1, 2, 3; 2, 3, 4, and 3, 4, 5, the
following interpolation formula is obtained:
c = 79.789 2.6077 t + 0.02935
(30)
AMMONIA IN WATER. 169
The specific gravity s t of the solution, saturated at
/ degrees, was,
c s\
Oo C.
10
20
1.0609
1.0547
1.0239
No. 24. AMMONIA IN WATER.
The following method, employed by Dr. Carius for
the determination of the absorption -coefficients of am-
monia, can be generally adopted when the gas under
examination is still more soluble than sulphurous acid.
The ammonia evolved from lime and sal-ammoniac in
the iron vessel a, Fig. 48, is purified by passing through
a wash -bottle b containing solution of potash, and then
Fig. 48.
170 METHOD EMPLOYED FOR
is led into the vessel c containing the boiled -out water
which is to be saturated. This vessel c is immersed in
a water -bath , the temperature of which is carefully
Fig. 49.
kept constant, and observed on the thermometer d. As
soon as it is presumed that the liquid is saturated with
gas, the lower part of the absorption -vessel, seen in
section in Fig. 50, is closed at u by a well ground glass
rod m, and the whole of the ammoniacal liquid above u
is carefully washed away, the space from u to n being
filled with distilled water. On opening the stopper r/i,
the saturated solution in v becomes sufficiently diluted
with the supernatant water to allow the ammonia to be
determined by a volumetric analysis with sulphuric acid.
The capacity of the vessel uv measured in cubic -centi-
VERY SOLUBLE GASES.
171
metres gives the volume V of the saturated water em-
ployed in the experiments; the volumetric analysis gives
the weight p of the ammonia ab-
Fig. 50. Fig. 51. sorbed at the temperature t of the
saturation, and under the pressure
P. The specific gravity -^ of the
saturated solution of ammonia cannot
be determined in a small bottle in
the usual way, because the slightest
increase of temperature, or even
merely pouring out the saturated
solution, would cause considerable
loss of gas. In order to avoid this
source of error, a carefully weighed
pipette, previously cooled in a
freezing -mixture, is filled up to a
mark w, Fig. 51, with the saturated
solution of ammonia, the excess of
which is quickly wiped from the outside, and the pipette
is then introduced into a weighed test tube half filled
with water, and the whole apparatus again weighed. If
the weight of the tube and water, together with that of
the pipette, be subtracted from the total weight, we
obtain the weight of the measured volume of liquid. The
volume of this liquid is found from the known capacity
of the pipette. In this way, the following specific gra-
vities s-i of the saturated ammouiacal liquid for the tem-
perature t , is obtained :
172
AMMONIA IN WATER.
c.
Capacity
of the
pipette
in grins.
Spec. grav.
! found.
Spec. grav.
from formula
31.
Difference.
1
0.58
2.5291
0.8531
0.8549
-j- 0.0018
2
4.60
2.5702
0.8670
0.8649
- 0.0021
3
9.54
2.5992
0.87G7
0.8756
0.0011
4
14.11
2.G2G1
0.8858
0.8845
0.0013
5
19.71
2.6454
0.8923
0.8924
-|- 0.0001
G
25.01
2.6654
0.8991
0.8984
0.0007
From the mean of 1, 2, 3; 2, 3, 4, 5; 4, 5, 6, we
obtain the interpolation formula:
Sl = 0.85355 + 0.0026269* 0.0000333 <* . (31)
By means of this formula the following table is cal-
culated :
c.
Spec,
grav.
Diff.
c.
Spec,
grav.
Diff.
C.
Spec,
grav.
Diff.
0.0021
0.0014
0.8535
9
0874G
18
0.8903
0.002G
0.0020
0.0013
1
0.8561
10
0.8766
19
0.8916
0.0026
0.0019
0.0012
2
0.8587
11
0.8785
20
0.8928
0.0026
0.0019
0.0012
3
0.8611
0.0026
12
0.8804
0.0019
21
0.8940
0.0012
4
0.8637
13
0.8823
22
0.8952
0.0026
0.0018
0.0011
5
0.8663
14
0.8841
23
0.89G3
0.0026
0.0017
0.0011
6
0.8689
0.0024
15
0.8858
0.0016
24
0.8974
0.0010
7
0.8713
16
0.8874
25
0.8984
0.0022
0.0015
8
0.8725
17
0.8889
The experiments conducted according to this method,
gave the following values:
AMMONIA IN WATER.
173
No. of the
experiment
Temperature
*C. of the
absorption.
Barometer
P.
Weight of
ammonia/), in
V= 5.0764
cbc. liquid.
The same
weight p in
V= 2.9646
cbc. liquid.
1
0.53
0.7553
1.9010
1.1127
2
4.60
0.7509
1.7924
1.0492
3
9.54
0.7509
1.6965
4
14.41
0.7546
1.6021
0.9376
5
19.71
0.7546
1,4988
0.8751
G
25.01
0.7525
1.3963
0.8138
By substituting these values in formula 27 , together
with the constant quantities for ammonia, we obtain the
following absorption -coefficients for ammonia in water:
No.
of the
exper.
C.
Coe
^
First
series.
'ficients fo
, --
Second
series.
and.
.
Mean
from
1 and 2.
Coefficient
from formula
32.
Diffe-
rence.
1
0.53
1032.3
1036.0
1034.1
1034.1
0.00
2
4.60
918.9
922.5
920.7
927.3
-f- 6.54
3
9.54
822.2
822.2
825.4
-|- 3.14
4
14.41
735.3
737.7
736.5
736.4
0.10
5
19.71
655.4
655.2
655.3
657.8
-f 2.54
6
25.01
586.5
584.8
585.7
585.7
-f 0.02
The numbers in column 6 are obtained from the
formula
c = 1049.63 29.496? + 0.67687 1* 0.0095621/3 (32)
calculated from the experimental values in columns 2
and 5.
174 AIR IN WATER.
No. 25. ATMOSPHERIC AIR IN WATER.
It has been previously shown that the relative pro-
portion in which the constituents of a mixture of gases
are absorbed by water does not alone depend upon their
several coefficients of absorption, but also upon the re-
lative proportions in which they are mixed. If the ab-
sorption-coefficients are different, the gases dissolved in
the water are not in the same relation as those in the
free gas. This last, undergoes therefore an alteration
in its composition varying with the relation of the mass
of the water to that of the gas. Hence the absorption-
coefficient of a mixed gas can only be calculated from
the relative proportions of the constituents and their
several coefficients of absorption, when the volume of
the gas is so great in comparison with the mass of the
absorbing liquid, that the alteration effected by the ab-
sorption in the composition of the residual gas is in-
appreciable. The true coefficient of absorption of at-
mospheric air can, therefore, be found in those cases only
in which these conditions are fully satisfied.
If we take the following as the mean composition
of the air,
Oxygen , <:> , . . 0.2096 =
Nitrogen . . . 0.7904 = N
1.0000
we obtain the required coefficient c for air and water
from the following equations:
V . -
- ~
0.76 (N + 0} ~ 0.76 (N + 0)
and by substituting the values 1 for V l and N -)- O, and
PRACTICAL APPLICATIONS. 175
0.76 for P, and the numerical values for and JV, we
obtain the equation:
c = 0.2096 a + 0.7904 ft.
Having thus determined the coefficients of absorption
of a series of gases, we may proceed to the practical
applications of the law of absorption.
If the volume of a simple gas, whose coefficient of
absorption is a, be twice absorbed by the same volume
h of water, at the same temperature, but under two dif-
ferent pressures P and P l , the amount of gas absorbed
in the two cases is, according to formula 2:
aPh
aP 1 h
0.76
Hence we have:
9i
.
Pi'
The following determinations made with the. ab-
sorptiometer show, within the limit of observational
errors, that the amount of carbonic acid g absorbed in
the same volume of water at the same temperature , in-
creases proportionally to the corresponding pressure P.
Carbonic acid at 199 C.
No.
P
g
P_
g
PI
9i
1 0.7255
38.G1
2
0.5215
27.24
1.38
1.42
3
0.5237
27.08
1.39
1.43
4 0.5231
27.23 1.39
1.42
17G
PRACTICAL APPLICATIONS
Carbonic acid at 32 C.
No.
P
g
P
P l
_9_
<7i
1
0.5244
31.41
2
O.G467
38.GG
0.8109
0.8125
3
O.G470
38.49
0.8105
0.81G1
This constant ratio between the absorbed gaseous
volume and the pressure to which it is subjected, is more
clearly seen in cases in which the partial pressures occur,
i. e. in which alterations of pressure are effected by
dilution with another gas. The formula 7 gives a con-
venient statement of this relation :
x-\-y
W B
A B
A_
W
By means of this formula, the composition of a mixture
of two gases can be calculated when the following quan-
tities are given : j the absorption - coefficient of the first
gas; /3 L that of the second; V the common volume of
both gases before the absorption, under the pressure P;
J 7 ! the residual volume after the absorption, under the
pressure P l \ and, lastly, the volume h of the absorbing
liquid. If the composition of the mixture calculated from
these experimental data coincides with that found by
direct eudiometrical analysis, we may conclude that the
formulae based upon the original premises are true, and
that the law is applicable not only for total, but also for
partial pressures.
The following experiments were made with mixtures
of carbonic acid and hydrogen.
OF THE LAW OF ABSORPTION.
177
EXPERIMENT I.
Eudiometric determination.
Pres-
Vol. at
Vol.
C.
C. and
sure.
l m press.
120.G
0.7214
13.6
82.87
After addition of carbonic acid
129.4
0.7269
13.5
89.63
Composition of the gas in 100 parts:
Hydrogen .... 92.46
Carbonic acid 7.54
100.00
Absorptiometric determination of the same gas.
Vol.
Pres-
sure.
C.
Vol. at
0C.
Volume ol' gas employed . . .
After absorption
180.94
122.01
0.5368
0.6809
15.4
5.5
171.29
119.61
Volume of absorbing water == 356.7
,, o5o.l
Mean . . . 356.4
From these data we obtain the following elements
of the calculation :
P 0.5368; V = 171.29;
P l == 0.6809; \\ = 119.61;
a = 1.4199; ft = 0.0193;
h = 356.4;
12
178
ABSORPTIOMETRIC ANALYSIS
and hence the composition is found to be :
Absorptiometric. Eudiometric.
Hydrogen . . . 0.9207 0.9246 = V
Carbonic acid , 0.0793 0.0754 = v
1.0000
1.0000
The composition of the gas remaining after the ab-
sorption is found by means of the formula? :
+
to be:
~ x + y "" AB L + A 1 B
Hydrogen . . . 0.9829
Carbonic acid . 0.0171
1.0000
As the gaseous mixture after absorption was sub-
jected to a^pressure P = O m 6809, the partial pressure
upon the carbonic acid was in this experiment:
u P l = O m 0116,
that of the hydrogen :
M! P l = O m 6692.
EXPERIMENT II.
Eudiometric determination.
Pres-
Vol. at
Vol.
c.
O n C. and
sure.
l m press.
G2.2
0.0449
39 03
After admission of carbonic acid
82.1
O.GG49
G.4
53.34
OF A MIXTURE OF TWO GASES.
Composition of the gas :
Hydrogen . . . 0.7319
179
Carbonic acid
0.2681
1.0000
Absorptiometric analysis of the same gas.
Vol. at
O n C.
Pressure.
C.
Volume of gas employed . . .
119.03
0.4951
6.8
After first absorption
72.02
O.G11G
5.1
After second absorption . . .
G0.39
0.7297
12.8
After third absorption ....
75.71
O.G020
23.3
Volume of absorbing water:
206.83
206.61
206.61
207.11
Mean
206.79
Hence we have for the first absorption experiment
P = 0.4951; T r = 119.03;
P l = 0.6116; V l = 72.02;
a = 1.4434; ft = 0.0193;
h = 206.79;
For the second Absorption :
P = 0.4951;
P, = 0.7297;
a ad 1.0726;
h = 206.79;
V = 119.03;
Fi = 60.39;
= 0.0193;
ft
12*
180 ABSORPTIOMETRIC ANALYSIS
For the third absorption:
P = 0.4951; V = 119.03;
P l = 0.6020; l\ = . 75.71;
a = 0.8555; ft = 0.0193.
h =206.79;
The calculation of the first absorption gives :
Absorptiometric. Eudiometric.
Hydrogen . . . 0.7343 0.7319
Carbonic acid . 0.2657 0.2681
1.0000 1.0000
The composition of the residual gas, remaining after
absorption, calculated from the eudiometric analysis, is:
Carbonic acid . '. . 0.0699
Hydrogen 0.9301
1.0000
Hence the partial pressure of the hydrogen is O ni 5688,
and of the carbonic acid O m 04275.
From the second absorption we obtain:
Absorptiometric. Eudiometric.
Hydrogen . . . 0.7372 0.7319
Carbonic acid . 0.2628 0.2681
1.0000 1.0000
This gives a residual gas of the composition :
Carbonic acid . . . -0.07712
Hydrogen .... 0.92288
1.00000
The partial pressure of the carbonic acid is here
0-0563, and of the hydrogen 06734.
OF A MIXTURE OF TWO GASES. 181
The third absorption gives the following results:
Absorptiometric. Eudiometric.
Hydrogen . . . 0.7285 0.7319
Carbonic acid . . 0.2715 0.2681
1.0000 1.0000
The residual gas after absorption, was hence found
to be:
Carbonic acid . . . 0.1036
Hydrogen 0.8964
1.0000
The pressure of the carbonic acid is, here O m 06236,
and of the hydrogen O m 5396.
The mean of these three determinations compared
with the eudiometric analysis, gives:
Absorptiometric analysis. Eudiometric analysis.
Hydrogen .... 26.67 26.81
Carbonic acid . . 73.33 73.19
100.00 100.00
It is impossible to determine a priori, the extent
beyond the limits already examined, for which the law
is true. It is, however, more than probable that in this
law, as in the law of Mariotte, a limit exists beyond
which the regularity of the action is disturbed by varying
molecular influences. The limits of exact action, de-
termined experimentally, are, however, quite extensive
enough to enable us to draw some very interesting con-
clusions from the subject. Eudiometry , for example,
gains from the law* of absorption an entirely new field
of action, enabling it not only to determine, without any
chemical experiments, the simple or complex constitution
of a gas , but also to recognize the nature of the com-
182 ABSORPTION IN LIQUIDS
poneut parts, even indeed to estimate their several pro-
portions, when once for all the coefficients of absorption
of the gases are known. In order to show that such an
absorptiometric determination can serve as a reagent
for the detection of gases, I choose an experiment with
marsh gas, which satisfactorily proves that results are
attainable, even when the values of the absorption -coef-
ficients employed in the calculation differ but little from
each other.
Relying on the results of eudiometrical analysis, it
has been hitherto supposed that the gas obtained by the
action of a hyxlrated alkali upon an alkaline acetate at
a high temperature was marsh gas. Although this sup-
position has scarcely ever been questioned, still all po-
sitive proof of the fact is wanting. Frankland and Kolbe
have shown that two volumes of marsh gas by eudio-
metrical explosion react exactly as a mixture of equal
volumes of hydrogen and methyl. Both give for every
volume a volume of carbonic acid, and require for their
combustion the double volume of oxygen. Eudiometric
analysis leaves it then undecided, whether the gas evolved
from the alkaline acetates is to be considered as marsh
gas, or as a mixture of methyl and hydrogen. By means
of absorptiometric analysis, this question is very readily
and decisively answered. If we start from the supposition
that the gas in question is a mixture of equal volumes
of methyl arid hydrogen , a volume V of the gas , at C.,
and under O m 76 pressure, measured in the absorptiometer
under a pressure P, would consist of
. methyl , and
P V
-r hydrogen.
2 . 0.76
A NEW REAGENT. 183
If this gas be agitated with /ij volumes of water, the
observed volume of the residual absorbed gas being V l
under the pressure P l , the sum of the absorption -coef-
ficients at the temperature of absorption (for hydrogen
! and for methyl /3 X ) can be calculated from the ob-
servations. If we call the residual hydrogen x { , and the
residual methyl yi (both reduced to C. and O m 76), this
x l will, iii consequence of its dilution with methyl, be
subject to the partial pressure - L ' ' . It is, however,
absorbed under this pressure by the volume 7^ of water.
The absorbed volume of hydrogen, reduced to C. and
O m 76 pressure, is therefore, according to the law of
absorption, -~jr a\ hi- This absorbed hydrogen plus the
ri
unabsorbed x^ is equal to the hydrogen originally present,
namely :
PV
2 . 0.76 l V,
or
PV
2 . 0.76 fl +
0.76 d
If the value of ^ is substituted in the expression , 7 - 1 - 1 ,
we obtain for the pressure of the hydrogen in the residual
unabsorbed gas
PV
2 (V\ + MO '
and for the pressure of the methyl in a similar manner,
PV
It follows, however, from the law of absorption, that the
184 ABSORPTION IN LIQUIDS
sum of the two partial pressures is equal to the observed
pressure PI. Hence we have :
P pv pv
2 (F, + V*,) " 2(F, +ftA,)'
or
PV 2 F!
"" + ft = : TTkAT ~T
An experiment made by Dr. Pauli with a gas pre-
pared by heating the acetate with hydrate of potash, and
carefully freed from elayl and carbonic acid with fuming
sulphuric acid and potash, gave the following elements
for calculation:
Original volume of gas reduced to C. Ji . ! .' . V = 11G.42
The pressure on this volume P = 0.50G5
Volume of gas reduced to C. after first absorption V l = 75.18
Corresponding pressure P l = O.GG15
Volume of absorbing water ........ A, = 318.11
Temperature of the absorption .... ."]. ;-. 128 C.
Absorption -coefficient of hydrogen at 12 8C. . ct*= 0.01930
Absorption -coefficient of methyl gas at 128 C. . ft = 0.0544G
Absorption -coefficient of marsh gas at 128 C. . y t = 0.0410G
The volume after second absorption reduced to C. F n = 79.04
Corresponding pressure . . *./ . r; *. ' . . . . . P n = 0.6561
Volume of absorbing water 7* n = 325.05
Temperature of absorption t n = 24G C.
Absorption -coefficient of hydrogen at 246 C. . n = 0.01930
Absorption -coefficient of methyl gas at 24G C. . ft, 0.04181
Absorption -coefficient of marsh gas at 24G C. . y n = 0.031GG
When this is calculated , negative values for cq -f- fti
and for a n -\- /? are found from both absorptiometric
experiments, namely: -- 0.3325 and 0.34807, instead
of the sums of the coefficients found in the experiments
for methyl and hydrogen: -f- 0.07376 and -f- 0.06111.
Hence the gas in question cannot consist of methyl and
hydrogen.
A NEW REAGENT. 185
If, on the contrary, the same elements are used in
the calculation of y Y and */, under the supposition that
the gas is a pimple one, two absorption - coefficients are
obtained, which are almost exactly the same as those
found from formula 14 for marsh gas, at the temperatures
1208 C. and 24o6 C. The formula
VP JV
gives in fact, according to table VI of the appendix, for
the temperature 128 C. the value of the coefficient to be
yi = 0.0439
instead of the actual value 0.041 1 ; and for the tempera-
ture 2406 C.
y n = 0.0333
instead of 0.03166. From this agreement we may con-
clude that the marsh gas prepared from acetate of pot-
ash is neither a mixture of hydrogen and methyl, nor a
body isomeric with natural marsh gas, but that it is ac-
tually the same substance which issues from the mud-
volcanoes of Bulganak in the Crimea.
Any general reaction to distinguish between the con-
stituents of a gaseous mixture has hitherto been wanting.
The quantitative composition of a gas obtained by eudio-
metrical analysis, depends almost entirely upon certain
suppositions regarding its qualitative constitution. If, for
instance, eudiometrical analysis points out the presence
of marsh gas, it remains quite undecided, as I have just
shown, whether or not this gas is a mixture of equal vo-
lumes of methyl and hydrogen. If analysis shows the
presence of a mixture of marsh gas and hydrogen , it is
uncertain whether we are experimenting upon mixtures
of methyl and hydrogen, or of methyl, marsh gas and hy-
drogen. All analyses in which the two latter gases occur
180 ABSORPTIOMETRIC ANALYSIS
together may be calculated according to either of these
assumptions, without it having hitherto been possible to
prove the accuracy of either one.
It is easy, by means of the law of absorption, to re-
move these doubts, for the absorption -coefficients serve
as the reagents which are wanting in gas analysis, and
they also present the peculiarity, that they do not only
show the qualitative, but at the same time the quantita-
tive composition of the gas. Let us, for example, sup-
pose that an unknown gas be mixed in an unknown vo-
lume or, with an unknown volume y of another unknown
gas, we can then, by means of three absorptiometric ex-
periments, determine, firstly, what gases are present in the
mixture, and secondly, in what proportions they occur.
The following is the method of solving this problem:
A sufficient quantity of the gas to be examined is col-
lected in the absorptiometer, and its volume, pressure
and temperature observed.
If the originally observed volume reduced to C.
be called F, and its pressure P, we obtain the equation
x
'- yp -r yp
Three absorptions of the gas are first made with the
volumes of water h^h^h^ and the corresponding volumes
for a constant temperature f, found to be, F x , P l ; F 2 , P 2 ;
F 8 , P 3 ; reduced to C. From these observations we ob-
tain the following equations, in which a denotes the ab-
sorption-coefficient of the first, and /3 that of the second
unknown gas at the temperature of the observations t:
i x i y
OF TWO UNKNOWN GASES. 187
: TrT i , 7, \ T> I 71
From these four equations the unknown quantities
., y. a, /3, are easily obtained. These two last are the
ordinates of absorption for two gases for the temperature
abscissa t. If the numerical values of these are calcu-
lated, the gas which has the same coefficient of absorp-
tion for corresponding temperatures is found in the
tables, and in this way the nature of the mixture determ-
ined. The values of x and y give also the relative pro-
portions between the constituents. In the case of two
gases the determination of a and ft is not difficult. If
we place PV = o, P l V l = a,, P 2 V 2 = ,, P 3 F 3 == a*
and PI J^ = 6 l7 P 2 h. 2 = 6 2 , P 3 /* 3 = 6 3 , we obtain in the
first place,
. &A
_ ,, 6 3 (o a f ) a d & g (a a,,) b t b 3 (g, a 3 ) (a
i * 3 (t - .)
and when the expressions on the right of these equations
are represented by A and B, we have,
a + ft = A ..... Ks->* . (34)
a P= A--B . ._._. . (35)
The sum of these two equations gives the value of a, their
difference that of ft.
By help of these values a and ft , we obtain, lastly,
(a 2 a -|- a 6 2 ) (q a -f /3 & 2 ) fi
^ = 6 2 ( _ ft
^^a ^. :; .^. ,,;:;..,. ; . ,,,,-. (37)
As an example of such a calculation , I select the
qualitative and quantitative determination of the gas pre-
pared by heating oxalic acid with concentrated sulphuric
acid. As this gas always contains an admixture of small
188
ABSORPTIOMETRIC ANALYSIS
quantities of sulphurous acid, it was first passed through
water containing oxide of manganese in suspension , and
the gas was not collected until the water had been com-
pletely saturated, and all the air expelled from the
apparatus. An eudiometric analysis of the purified gas
gave:
Pres-
Vol. at
Vol.
C.
C. and
sure.
l m press.
Original volume
142.9
O.G9G5
20.2
92.70
After absorption of carbonic acid .
74.6
O.GG37
19.0
.46.29
Carbonic oxide
Carbonic acid .
Found.
'50.0G
49.94
Calculated.
50.00
50.00
100.00
100.00
The absorptiometric determination, which was so con-
ducted that the amount of absorbing water It was in-
creased after every observation, gave the following ele-
ments :
Vol. at
Pres-
Volume
C.
of water
0C.
sure.
= h.
Gas employed
500.8
0.5760
19.0
o
After the first absorption ....
384.0
0.6882
19.0
81.6
After the second absorption . . .
340.0
0.7015
19.2
186.9
After the third absorption ....
2833
0.7415
19.0
335.5
From these elements the value of /? is found, accord-
ing to formulae 34 and 35, to be 0.1)248. The table of
OF TWO UNKNOWN GASES. 189
coefficients VI shows that carhonic acid gas possesses
the coefficient of absorption 0.9150 at the temperature
190 C. of the experiment, and that it therefore differs but
slightly from that just found. We are in the habit of con-
cluding from the consistence of a precipitate, from its co-
lour, solubility &c. that a certain substance is present. In this
case we have a certain definite ordinate of a curve of solu-
bility, fixed by previous experiment which serves as a rea-
gent in place of the precipitate. As, however, we are ac-
quainted with many substances which produce precipitates
so much alike that they cannot be employed as a means
of recognition, we may also find that these ordinates so
approach at a given temperature by which the curves of
solubility touch or cut one another, that a second absorptio-
metric experiment is necessary. The foregoing experi-
ment may serve as an example of this difficulty ; we find
the experimental value of a to be 0.0204 ; a number which
differs but very inconsiderably from the coefficient of
carbonic oxide, as found in the tables for the tempera-
ture 19 C., viz 0.0233. The coefficients for both hydro-
gen, and sethyl, 0.0193 and 0.0207, differ however, so
slightly from this experimental value, that we cannot de-
termine with certainty which of these three gases is present.
In this case the absorption -coefficient of water is to be
compared to a reagent which indicates the presence of a
group of bodies. It only remains, to determine by ab-
sorptiometric experiments, either at varying temperatures,
or with other liquids, which of these three gases is con-
tained in the mixture under examination. The deter-
mination of the absorption - coefficients of gases for
alcohol, for saline solutions, and other liquids, forms
therefore an important element in gasometric investi-
gations as from these a number of equations are ob-
190 ABSORPTIOMETRIC ANALYSIS
tainable, each of which possesses the value of a new
reagent.
If the material nature of the gas has been deter-
mined from a and /3 by the method described, it is only
necessary to substitute these values of a and /3 in the
equations 36 and 37, in order to be able to calculate the
quantitative relation to which the two gases are mixed.
This calculation made for the above experiment with
the values of a and /3 found in the tables of carbonic acid
and carbonic oxide, gives:
Eudio-
metric.
First
experim.
Absorpt
Second
experim.
ioinctric.
*- ^M^"i
Third
experirn.
Mean.
Carbonic acid .
Carbonic oxide .
50.06
49.94
50.00
50.00
50.03
49.97
50.34
49.GG
50.12
49.88
100.00
100.00
100.00
100.00
100.00
The same elements which have served to determine
the qualitative nature of the mixture of gases, give there-
fore the quantitative composition with a degree of accu-
racy scarcely surpassed by eudiometric analysis.
In the following experiment a mixture of carbonic-
acid and marsh gas was employed, and the liquid used
for the absorption was absolute alcohol. The eudiome-
tric analysis gave:
OF TWO UNKNOWN GASES.
191
Vol.
Temp.
Pres-
sure.
Vol. at
C. and
l m press.
Carbonic oxide
185.0
5.4
0.5874
106.56
After addition of marsh gas . . .
3335
5.7
0.6462
111.11
Carbonic oxide 50.48
Marsh gas 49.52
100.00
The elements of the absorptiometric determination
were:
Vol. at
|
Volume
Pressure.
C. : of alcohol
C.
= h.
Volume of gas employed .
326.69 0.6462
5.7
After first absorption . . .
203.44 0.6533
5.4
50.7
After second absorption . .
197.80 0.6580
5.4
74.7
After third absorption . . 193.42 0.6624
5.4
94.4
Hence the coefficient a is found to be = 0.5084, and
ft = 0.2139. The two gases whose coefficients at a tem-
perature of 54 C. agree with these numbers are marsh
gas and carbonic oxide, as is seen from table VI in the
appendix, where the first is found to be 0.5075 and the
second 0.2139. As the other tables do not contain any
other coefficients which so nearly approach the numbers
found, we may consider the qualitative nature of the mix-
ture thereby determined. The calculation of the quanti-
tative composition gives the following results :
192
APPLICATIONS OF THE
Eudio-
inetric
Absorptiometric.
First
experim.
Second
experim.
Third
experim.
Mean.
Carbonic oxide .
Marsh gas .
50.48
49.52
50.60
49.40
50.59
49.41
50.5G
49.44
50.58
49.42
100.00
100.00
100.00
100.00
100.00
Another problem which can be solved by help of the
law of absorption, concerns the alterations which a mix-
ture of gases undergoes on contact with water. The fol-
lowing example of a similar mixture of carbonic acid and
carbonic oxide shows how considerable such alterations,
even with relatively small amounts of liquid, may under
certain circumstances become; and to what serious errors
those eudiometric experiments may be subject in which
the gases are confined over water, or liquids instead of
solids are employed as absorbents.
The gas employed in this experiment was again that
evolved from oxalic and sulphuric acids. The following
elements for the calculation were obtained from an ex-
periment made by Dr. Atkinson :
V = 388.4; V, = 247.69;
P = 0.6557; P l = 0.7395;
a =rr 0.9124.
* == 315.3;
** = 0.02326 ;
These values substituted in formula 7, gives the following
composition of the gas employed:
* Called
** Called
in formula 7.
in formula 7.
LAW OF ABSORPTION OF GASES.
193
Absorptiometric.
Carbonic acid 49.55
Carbonic oxide 50.45
100.00
Calculated.
50.00
50.00
100.00
Absorptiometric analysis, leads therefore, as before, to
the values V = 0.4955 and V = 0.5045.
From this is obtained, by means of equation 6, the
composition of the residual unabsorbed gas :
Carbonic acid 31.87
Carbonic oxide 68.13
100.00
A eudiometric analysis of the residual gas , made by
Dr. Atkinson, agrees in a satisfactory manner with this
calculated composition. He found:
Volume.
Pressure.
c.
Vol. at
C. and
l m press.
Original volume ....
9G.1
O.G721
18 7
60.45
After absorption of the
carbonic acid ....
Carbonic aci
Carbonic ox
68.0
d
0.6556
19.3
. 31.12
68.88
41.64
de
100.00
The quantity of carbonic oxide contained in the ga-
seous mixture has therefore increased from 50.45 to 68.88.
although the volume of absorbing water was not so large
as that of the gas.
The phenomena which accompany the evolution of
gas in mineral springs , can only be fully understood by
13
194 GASES ABSORBED
the help of the law of absorption. " Among the non - alka-
line springs, containing but a small quantity of dissolved
salts, there are some whose absorption -coefficients differ
but slightly from those of pure water, and contain carbo-
nic acid gas alone in solution. If such springs, as is usu-
ally the case, are saturated with gas, a certain limit for
the amount of contained carbonic acid may be found.
This limit of the quantity of carbonic acid, depends:
firstly upon the temperature of the spring; secondly on
the depth of the shaft of the spring ; thirdly on the height
of the spring above the sea.
Springs of the above description, which are saturated
with a stream of chemically pure carbonic acid, and rise
without pressure at the level of the sea, give according
to their temperature very different amounts of gas. They
contain in one litre of water the following amounts of
gas for the corresponding temperatures :
C. Cbc. of gas in 1 litre of water
1796.7
5 1449.7
10 1184.7
15 1002.0
20 901.4
If the same spring , under otherwise similar circum-
stances, rose at an elevation above the sea where the
average atmospheric pressure was only two - thirds of the
mean height of the barometric column , it would contain
only two -thirds of the above amount of dissolved car-
bonic acid.
Hence, it will be perceived, that the amount of gas
in a spring which is saturated with pure carbonic acid,
may be considerably argumented by deepening the spring
shaft, and thus increasing the column of water under
IN MINERAL SPRINGS. 195
which the gas issues from the earth, as Bischoff has in-
deed already shewn in his admirable researches on the
phenomena of springs. If, for example, the depth of the
shaft from the surface of the spring to the ground is 15
feet, the water where it bubbles out from the earth will
contain one third more carbonic acid than the above
amounts shew. The water in rising to the surface loses
a part of the dissolved gas in proportion as the pressure
diminishes, but the statical equilibrium which ensues, in
consequence of the law of absorption , requires a certain
time for its restoration. Thus the Peter's Spring in Pe-
tersthal in the Schwarzwald, which has a temperature of
10 C., contains at the surface of the spring, under a pres-
sure O m 735, 1270.4 cbc. of carbonic acid in the litre;
whereas, according to the absorption -coefficient of car-
bonic acid for 103, it should only contain 1133.3 cbc.
under the same pressure. The water is therefore super-
saturated with carbonic acid. This excess of gas is seen
to escape in small bubbles from the water when a vessel
filled at the spring is allowed to stand. By agitation the
equilibrium is restored in a few moments, and the gas
dissolved in the water reduced to its normal amount. From
similar considerations, it is easy to see that many of the
statements, with regard to the amount of carbonic acid
contained in springs, must be false. Thus , for instance,
the amount of carbonic acid contained in the ,,Fursten-
Quelle" in Imnau, is given by Sigwart to be 2500 cbc.
in the litre. Under the mean pressure, and at the tem-
perature of the spring 63 C., the water can, however, ac-
cording to the law of absorption, only contain 1373.2 *
* The small amount of solid constituents contained in the water
(not more than 9 grains in the pound), cannot appreciably alter
the absorption - coefficients, certainly not increase them.
13*
19G GASES ABSORBED IN
cbc. after the equilibrium has been established. The
amount of gas 2500, requires a pressure of I m 3836 of
mercury, or a column of water of 8 m 449 to be added to
the mean barometric pressure. As, however, it is impos-
sible to suppose that the Imnau spring rises under the
pressure of a column of water at least 25 feet high, and
as a saturation of nearly double the amount of gas is as
improbable, we are compelled to assume that Sigwart's
experiments are erroneous. The falsity of many other si-
milar statements may thus be easily shewn.
The relations which are found to exist between the
free and absorbed gases of a spring by means of the law
of absorption, give a fixed starting-point from which to
estimate the influence which an amount of nitrogen in
the free gas in a spring exerts upon the quantity of car-
bonic acid dissolved in the water. The second and third
columns of the following table , calculated from the pre-
ceding formulse, show the percentage amount of carbonic
acid and nitrogen in the absorbed gas for the cor-
responding percentages of nitrogen in the free gas given
in the first column. The temperature of the water is
supposed to be 151 C.
Amount of nitrogen
Gas absorbed
in the spring water
in the free gas.
-^- " _
nitrogen.
-^
carbonic acid.
I.
II.
HI.
10 per cent
1.613
98.387
20
3.558
96.442
30
5.949
94.051
40
8.958
91.042
50
12.861
87.139
60
18.127
81.873
70
25.623
74.377
80 ;
37.123
62.877
90
57.052
42.948
MINERAL SPRINGS. 197
From this table it is plainly seen, that if the gas
passing through a spring at 151 C. contains only 10 per
cent of carbonic acid with 90 per cent of nitrogen, the
gas dissolved in the spring water will contain 42.948 per
cent of carbonic acid. In this way it is easy, in analysis
of mineral waters, to calculate the composition of the
gases contained in the water, if the composition of the
gas which is set free in the spring is known by experi-
ment. If the composition of both gases is directly deter-
mined , and the experimental composition agrees with
that found by calculation, we have a most valuable con-
firmation of the correctness of both analyses.
All these deductions from the law of absorption are
of course only applicable to cases in which a statical
equilibrium between the free and dissolved gases can
ensue. This is not only the case in springs through which
gases pass, but particularly in rain and dew, and the
law is applicable to these with the greatest precision.
198 LAWS OF THE
DIFFUSION OF GASES. *
JLf a long vertical tube closed at the lower end, be half
filled with hypochlorous acid, or any other coloured gas,
a colourless column of air is seen in the upper {>art of
the tube resting on the coloured gas below. If a portion
of the air be withdrawn before a mixture of the gases
has occurred, the surface of contact of the two layers, as
seen by the coloured gas , rises in consequence of the in-
creasing expansion, and the pressure, measured by a ma-
nometer attached to the side of the tube, is altered in a
similar manner in all the layers of the two gases. Hence
we may conclude that the particles of different gases exert
the same pressure on each other as the particles of simi-
lar ones.
Occurring together with, although entirely indepen-
dant of these actions of pressure, we observe another
phenomenon; namely gaseous diffusion. This pheno-
menon depends upon the property of gases mutually to
penetrate into each other from their surfaces of contact,
with velocities determined by their chemical natures,
* The results communicated under this heading are derived from
an unfinished , and still unpublished research which the author
made some years ago in conjunction with Professor Stegmami.
DIFFUSION OF GASES. 199
until the density of each constituent has become the same
throughout the whole mass. If the two gases are sepa-
rated by a porous diaphragm, as, for instance, a piece of
dried gypsum, whose pores offer so large a fractional re-
sistance that the velocity of issue for gases , even when
they are forced through under a considerable pressure,
remains but small, it is still found that an exchange of
gases goes on through such a diaphragm with consider-
able rapidity. If the pressure above and below the dia-
phragm be always retained the same, it is found that the
volumes of the gases which pass through in both directions
during the same time are not equal, and therefore, that
gases pass through such porous diaphragms with veloci-
ties dependant upon their essential natures. It is not
possible to determine the diffusion -velocity of two gases
whilst they freely communicate with each other, because
the motion effected by the diffusion is not the only phe-
nomenon observed ; for when two gases penetrate into
each other with different velocities, the total pressure
thus altered, must adjust itself and effect motions enti-
rely independant of those which diffusion alone would
have caused in each separate gas. In researches upon
diffusion we must therefore especially guard against the
disturbing influence of unequal pressure. In order to be
able to fulfil these conditions for gases, whose volumes
are undergoing continual alteration, we may employ an
instrument called the diffusiometer which has the following
arrangement. Fig. 52 (seep. 200) a a represents a rod of
wood moveable in a vertical direction through the sockets
cc, to which the vessel containing the gas, whose pressure
is to remain constant, is attached by the small bent iron
clamp I. The axis d is fixed between the two arms kk
(firmly attached to the rod a a) by means of a piece of
200
LAWS OF THE
cat-gut wound round the axis at <j and drawn tight by a
violin key at v. By turning the wheel p (which revolves
against a steel spring e , and forms the end of the axis
c/), either to right or left on its centre, the rod a can
Fig. 52.
easily be moved in a vertical direction either upwards or
downwards. As this motion is diminished in the propor-
tion of the radius of the wheel p to that of the axis d, a
relatively large motion of the wheel effects a very slight
DIFFUSION OF GASES. 201
upward or downward movement of the tube m containing
the gas. If this tube be dipped into a cylinder filled with
mercury, it is easy to keep the metal in the tube at the
same level as that in the cylinder to within O. mm l by
turning the wheel p whilst the meniscus is observed
through the telescope h h.
Graham, to whom we are indebted for the important
discovery of the phenomena of gaseous diffusion , found
that a definite relation existed between the volume of air
exchanged for a volume of gas diffusing into the air.
through a porous diaphragm and under a constant pres-
sure, and the volume of diffused gas itself; and he found
that this definite relation more or less nearly approached
that of the inverse square - roots of the specific gravities
of the gases. A theoretical explanation of this particular
numerical relation has been attempted by the supposition
that a gas diffuses into another gas of different constitu-
tion, according to the same laws which regulate its pene-
tration into a vacuous space , and that in the case of dif-
fusion of two gases, the motion proceeds with the same
relative velocity as it would have done had they both of
them diffused into a space free from air. As the velocity
of issue of gases into a vacuum is found both by theory
and experiment to be inversely proportional to the square-
roots of their densities, only when the efflux occurs from
fine openings in thin plates, and not through capillary
tubes, we see that this theoretical explanation rests on
the improbable supposition that a porous diaphragm acts
towards gases like a system of fine openings in thin plates.
Hence it appeared necessary, in order to test the truth of
the generally adopted theory of diffusion, especially to
examine the phenomena occurring in the transit of gases
through porous diaphragms. For this purpose the appa-
202 LAWS OF THE
ratus represented by Fig. 53 was employed. The tube d
is graduated and calibrated, and closed by the diaphragm
of gypsum b. This tube is connected with the head C by
Fig. 53.
DIFFUSION OF GASES. 203
an air-tight vulcanised caoutchouc joining Z>, so that a
current of gas can be brought , from the delivery tube e
by means of the small caoutchouc tube i, immediately
above the surface of the porous plate b. The ground
glass stopper o serves to shut off the communication be-
tween the plate of gypsum and the current of gas, by mov-
ing the glass rod w, working air-tight in the vulcanised
caoutchouc cap E. In cases in which the gas is required
to be withdrawn for analysis at any given period of the
experiment, the small exit tube p furnished with a caout-
chouc ventile g, may be used.
The following is the method employed when we have
to determine the velocity with which a gas passes through
the plug of gypsum. The diffusion -tube just described
(Fig. 53) is first fastened on to the bent iron clamp b of
the diffusiometer (Fig. 52) ; the stopper o (Fig. 53) is then
lifted by means of the glass rod m, which, in order to
keep it in its place, is fastened by a thread to a little
hook on the wooden rod aa. If the diffusion-tube be now
sunk into the mercury by turning the wheel of the diffusio-
meter, whilst the ventile q is closed, the air contained in
the tube will escape through the porous plug b. If, on
the other hand, a continuous current of gas be passed
through the head C of the instrument whilst the tube is
raised above the mercury, it becomes filled with the gas
pressed through the diaphragm. As soon as the atmospheric
air has been completely displaced from all parts of the
apparatus by successively filling and exhausting, the tube,
which dips in mercury up to the exit tube qp, is rapidly
drawn up, without discontinuing the evolution of gas
through the head C. By this means, the column of mer-
cury in the tube is raised above that in the outer cylin-
der. In order that this column of mercury should always
204
LAWS OF THE
remain at the same height during the entrance of the gas,
the float b b , Fig. 54 , resting on the outer level of mer-
cury is employed. This float is made of a circular piece
Fig. 54.
of cardboard which moves over
the glass tube with very little
friction and is furnished with
more substantial ends cc in order
that the circular form should be
retained. In this screen six small
windows are cut, three on each
side opposite to one another ; and
the lower edges of these sets of
three windows a a, ^a^ a 2 a 2 are
all at a known distance from the
lower end c of the paper cylinder.
As soon as the mercury me-
niscus in the inner tube has sunk
so far as to coincide with the
lower edge of one of the win-
dows, this level of mercury is
kept constant by turning the
wheel of the diffusiometer, and
then the length of time observed
which elapses until 5 divisions
on the tube (in which the level of mercury is kept con-
stant by turning the wheel) pass across the lower edge of
the little window. These observations can be read off to
the tenth of a millimetre by means of the telescope hli.
If the constant height of the column of mercury ex-
tending from the end of the cylinder to the lower edge
of the window be called p, the volume of the tube corre-
sponding to the 5 divisions (determined beforehand by
DIFFUSION OF GASES.
205
calibration) F, the height of the barometer P, and the
time which elapses until 5 divisions are passed t< the vo-
lume V l of gas which passes through in the time 1, and
under the pressure 1, is found from the equation:
The following experiments made with oxygen, hydro-
gen, carbonic acid, and air show, that within certain li-
mits, the issued volumes of gas, reduced to equal pressure,
are proportional to the pressure under which they issue;
although it is to be remarked that the rate of issue varies
considerably from this law under large amounts of pres-
sure.
Oxygen into oxygen.
II.
III.
Temperature
12C.
12 C.
1'2 C.
Barometric pressure
O m 7452
O m 7452
O m 74T)2
Time of diffusion in seconds . .
259
198
102
Diffused gas at l m pressure . .
25.49
39.14
31.19
Velocity of diffusion V l ....
0.09841
0.1977
0.3058
Difference of pressure p . . . .
0"01G7
O m 0335 '
0>0520
Value of .
5.893
5.901
5.881
P
20G
LAWS OF THE
Hydrogen into hydrogen.
IV.
V.
VI.
Temperature
14C.
14C.
14C.
0^7452
O m 7452
O7452
Time of diffusion in seconds . .
82
53
37
Diffused gas at l m pressure . .
21.85
28.4G
31.19
Velocity of diffusion F x ....
0.26G5
0.53G9
0.8431
Difference of pressure p . . . .
O m 01G7
00338
O m 0520
Value of l
1 59 G
1.589
1.G21
P
Carbonic acid into carbonic acid.
VII.
VIII.
Temperature ...
05 C
05 C
Barometric pressure
O m 7477
O m 7477
Time of diffusion in seconds . .' .'
Diffused gas at l m pressure . . **
Velocity of diffusion V " '
129
21.93
1700
41
14.29
3485
Difference of pressure p . . . . .
Value of l .
001G7
1 018
00333
1 04G
P
DIFFUSION OF GASES.
207
Air into air.
IX.
X.
07452
254
12C.
07452
115
Barometric pressure
Time of diffusion in seconds . . .
Diffused gas at l m pressure . .7,^ "\
21.31
0.0839
O m 0350
2.397
20.20
0.175G
O m 072
2.439
Difference of pressure p
Value of *
P
In experiments I and IV, as in experiments III and
IV one and the same porous diaphragm of gypsum was
used 46 mm thick and dried at 60 C.
The rate of issue of oxygen is found for these expe-
riments to be to that of hydrogen in the proportion of
1 to 2.71, and of 1 to 2.76 or a mean of 1 to 2.73. The
velocity with which both gases effuse from fine openings
in thin plates is inversely proportional to the square roots
of their densities, and the relation instead of being
1:2.73, as in the foregoing example, should have been
as 1:3.995. Hence it is plain, that the pores of the
gypsum do not act towards gases passing through
them, as a system of fine openings in thin plates,
but as a system of capillary tubes, and that there-
fore an explanation of the phenomena of diffusion which
is based upon the laws of the rates of effusion of gases
from fine openings cannot be correct
Under these circumstances we thought it adviseable
208 LAWS OF THE
to return to the experimental data of the original theory
of diffusion , and to determine in the first place the fol-
lowing questions by new experiments:
1) Does a specific attraction of the porous surface of
the diaphragms through which the gases pass exert
a disturbing effect upon the phenomena of diffusion?
2) Does the relation between the volumes of the ex-
changing gases remain constant during the whole
course of the experiment?
3) Do the volumes of two gases which have diffused
into each other, stand to each other, as is univer-
sally admitted, inversely as the square roots of their
densities ?
In order to decide the first question all we require is
to determine whether the pores of the gypsum act simply
as an empty space, or whether gases possess determinate
absorption - coefficients for gypsum as for liquids. We
have therefore, to determine the coefficients of absorption
of various gases for a solid body, for gypsum. The fol-
lowing was the method employed.
The diffusion - tube, Fig. 55, is furnished with a lid d
which can be hermetically closed by pressure against a
plate of caoutchouc ; below the lid, a cake of gypsum from
half an inch to an inch in thickness is cast, and a cur-
rent of gas is led into the tube immediately below the
cake of dried gypsum b (when the lid is closed), until
all atmospheric air is expelled from the porous dia-
phragm as well as from the diffusion tube. The volume
of gas contained between the gypsum and the mercury
was then measured under various pressures, which were
easily attained by raising the tube in the mercurial
trough. The volume V under the pressure P, and the
volume V l under the pressure P 1 are thus found. The
DIFFUSION OF GASES.
209
volume F, which represents the gas in the tuhe and not
that contained in the diaphragm, would, according to
Mariotte's law, occupy under the pressure PI a volume
Fig. 55.
PV
equal to -= together with the vo-
lume of gas which has issued from
the gypsum owing to the diminu-
tion of pressure from P to P lf If
we call this latter volume 10, we
have :
1) ^+.= F,.
If now, a represent the absorp-
tion - coefficient of the gypsum dia-
phragm, i. e. the volume of gas, re-
duced to 0.76 pressure and C.,
which is contained in the unit vo-
lume of the gypsum (measured in
the volumes of the diffusion tube);
and if v represent the volume of the
diaphragm, the quantity of gas ab-
sorbed by the diaphragm under a
. Pav
pressure P is when reduced to
0.76, and under a pressure PI *
0.7 b
Pav
also reduced to 0.76. TT^TT therefore represents
0.7 b <7t^
P } av
0.76
,the volume of gas, reduced to 0.76, which has issued from
the porous diaphragm upon the diminution of pressure
from P to PI. Under the pressure P l this volume of gas
becomes :
av -r- 1 )
210 LAWS OF THE
This value substituted for w in equation 1 gives us :
V l P l VP
p -
&.V.
The following experiments show that the value of
a v does not materially alter for " various gases. An ex-
periment with hydrogen gave :
V
p
V
20.G
0.7287
27.7
O.G344
27.2
30.9
0.5981
2G.8
32.7
0.5802
2G.7
37.7
0.5375
27.5
Mean value oi ttv 27.1.
The first column V contains the volumes of gas, cor-
rected according to the table of volumes, and read off
on the closed diffusion tube; the second P gives the cor-
responding pressures observed ; and the third the cal-
culated values of av. In these and the following ex-
periments no change of temperature occured.
A similar experiment repeated with moist atmospheric
air, after the same diaphragm had been exposed for
some hours to the air, gave the following results:
V
P
V
33.2
0.7290
40. ">
O.G525
27.75
47.0
0.5947
27.90
Mean value of ctv 27.82.
DIFFUSION OF GASES.
211
Two other experiments with air and carbonic acid
made with another diaphragm of gypsum at different
temperatures gave:
Air.
V
*C.
P
V at C.
ctv
1 I
150.9
3.0
0.7537
149.3
204.6
6.8
0.5750
200.4
15.12
Carbonic acid.
V
<c.
j)
Fat 0C.
cev
141.2 86
0.7527 13G.9
192.4
9.3
0.5689
186.1
1523
From the constant valuej of a v we may therefore
conclude, that no actual attraction takes place between
the porous surface of the gypsum and the gases contained
in the pores, but that these pores act towards the in-
closed gases as a simple vacuous space. Hence phenomena
of absorption, as exhibited in the action of gases and liquids,
cannot occur when gases diffuse through a diaphragm of
gypsum.
Up to the present time the relation between the volume
of gas which has entered, and that which has issued
from the diffusion tube, has been determined only by as-
certaining the volume of the gas before the experiment,
and after the exchange was completed. Independently,
however, of the fact that the volume of the escaping gas
strictly speaking never can reach 0, but only indefinitely
14*
212 LAWS OF THE
approaches this limit, a practical difficulty occurs which
renders it impossible to recognise the point at which the
quantity of the issuing gas even approaches the zero.
This difficulty becomes evident when we consider, that
the only method by which we can determine whether the
diffusion is complete or not, is by observing whether or
not the inner level of mercury in the diffusion tube rises to
a notable height above the outer level in the cylinder. As
soon, however, as the gas in the diffusion tube has been
diluted to a certain extent by another gas entering the
tube, the rate of issue of the first gas will be so re-
tarded, that even an imperceptible column of mercury is
sufficient to cause as much gas to enter the tube as dif-
fuses out from the interior. No elevation is then ob-
served of the mercury in the diffusion tube , although an
analysis of the gaseous contents of the tube would give
evidence of the presence of a considerable residue of the
original gas, proving that the diffusion is by no means
completed. Even by employing more accurate means of
measurement, so that O.l mm column of mercury or water
could be accurately observed, it is impossible to obtain
satisfactory accordance in the numerical values for dif-
ferent observations. This is clearly shown in the fol-
lowing experiments, in which a continually renewed cur-
rent of oxygen, was allowed to diffuse into a finite volume
of hydrogen contained in the diffusion tube. The ex-
periment was conducted with the apparatus represented
in Fig. 52.
EXPERIMENT 1. The original volume of hydrogen
amounted to 230.7. The wheel of the diffusiometer was
so turned during the experiment, that the inner level of
mercury was never elevated above the outer level by the
DIFFUSION OF GASES. 213
perceptible difference of O.l mm . At the beginning of the
experiment the diffusion proceeded at the rate of a di-
minution of 5 volumes in 10 seconds. After the expiration
of 524 seconds, when the volume of hydrogen in the tube
was reduced to 68.3, this same diminution of volume re-
quired 112 seconds. Now it required nearly this time
(112 seconds) to press 5 volumes of air through the
diaphragm under the pressure of O.l mm of mercury.
Beyond the volume 68.3, therefore, no further observation
was possible. In this way, the diffusion, when followed
to its furthest observable limit by help of the most ac-
curate measurements, gave a relation between the hy-
drogen which had issued, and the oxygen which had
O1 Q J
entered, represented by the number PQ ' = 3.127. Ac-
oo.o
cording to the previous supposition, namely that this
relation is that of the inverse square - roots of the den-
sities it should have been
= 3.995.
V 0.06926
EXPERIMENT 2. In order to diminish the original
volume of hydrogen 183.5 by 5 volumes, 8 seconds were
required. After the volume had become 63.2, and no
longer admitted of exact observation a diminution of
5.1 volumes required 101 seconds. Under the supposition
that the exchange of gases was completed (as further
observation was impossible), the number obtained is 2.903
instead of 3.995, as required by the former theory.
In both these experiments, on account of the opacity
of the mercury, the inner meniscus in the tube was ob-
served about 0.1 mm above the level of the mercury in the
outer cylinder, so that the density of the gas contained
214 LAWS OF THE :
in the tube was very slightly less than that of the sur-
rounding atmosphere. This small difference of pressure
acted therefore in such a way that the amount of gas
remaining in the tube after the diffusion was a little too
large. The experiment was therefore repeated, with the
difference that a small piece of cardboard was placed
on the surface of the mercury within the tube, and
this float kept at a level with the outer surface of mer-
cury by reading off with the telescope. By this means
the internal pressure was necessarily somewhat greater
than the external one throughout the experiment. Even
under these more favorable circumstances, the relation
between the exchanged gases was always found to be
below the number 3.995 required by theory.
EXPERIMENT 3. An attempt was next made to
decrease the sources of error necessarily present in the
former experiments to the minimum amount, by making
use of water as a liquid specifically lighter than mercury,
and by increasing the dimensions of the diffusion tube
and porous diaphragm. The diffusion tube employed was
about 2 feet long, and 1 inch in diameter. It was filled
with hydrogen which diffused freely into the atmosphere.
The observations of the heights were made with the te-
lescope, so that the difference between the meniscus of
the water (which was not boiled -out) inside and outside
the tube was always kept below one millimetre. The
instrument, filled with air, was then placed so that a
difference of pressure of 15 mm was kept constant, and the
time was observed during which 5 volumes of air had
entered. This was found to amount to 12.5 minutes. A
difference of pressure of l mm of water would therefore
produce an error, from air forced in, of 1 volume in
37.5 minutes.
DIFFUSION OF GASES. 215
In an experiment of this kind, conducted with every
precaution, in which hydrogen diffused into air, the
original volume of hydrogen at O'O" was 645. After 21
seconds it was 635, after the next 21 seconds 625, after
the next 26 seconds 615, after 32' 7", and the following
times the volumes were:
Time.
Volume.
32' 7"
225
33' 27"
220
35' 10"
215
37' 8"
210
39' 53"
205
43' 41"
200
49'52"
195
62' 25"
193
74' 44"
193
114' 10"
194
151' 0"
195
The last four observations were made whilst the
internal meniscus was l mm higher than the external one.
From this experiment it is clearly seen that the diffusion
had become inappreciable after the observation at 62' 25",
for the two last observations show an increase of volume
of 1 for a difference of pressure of l mm in from 39 to
37 minutes, which according to the former experiment
must occur if the difference of pressure were the sole
cause of the alteration of level. If, therefore, we suppose
that the diffusion has become infinitely small at a volume
of 193, we obtain a relation for the exchanged volumes
of - J- = 3.34, which still differs considerably from the
i Jo
theoretical number = 3.80.
21G
LAWS OF THE
From these experiments we are forced to conclude
that the diffusive interchange does not occur in the re-
lation of the inverse square -roots of the specific gravities.
We may, therefore, now inquire, what is the true
relation between the volumes of gases interchanged during
the diffusion, and how far this relation remains constant
during the course of the phenomenon. These questions
can be answered when the composition of the gas con-
tained in the diffusion tube is determined at successive
periods of the diffusion. For this purpose, the following
experiment was made with hydrogen, and a current of
oxygen passing rapidly over the gypsum diaphragm.
Number
of the
observations.
Volume of
gas in the
. diffusion
tube.
Time
in
minutes.
1
385.2
9
2
381.2
?
3
376.2
9
4
371.2
y
5
3GG.2
12.98
6
3G1.2
16.38
7
356.2
19.96
8
351.2
23.55
9
346.2
27.25
10
341.2
30.95
11
336.2
34.71
12
331.3
38.70
13
326.3
42.16
14
321.4
46.16
15
316.5
50.25
Gas collected.
DIFFUSION OF GASES.
217
Number
of the
observations.
Volume of
gas in the
diffusion
tube.
Time
in
minutes.
16
192.3
o-.o
17
184.2
7.40
18
179.4
11.72
19
174.6
16.05
20
169.8
20.53
21
164.9
25.25
22
160.1
30.18
23
155.3
35.22
24
150.6
40.48
25
145.8
46.20
Gas collected.
Immediately after the 15th observation, the dif-
fusion tube was closed by the stopper, and a sample
of gas collected, which gave the following analytical
results.
Vol.
Pres-
sure.
Temp.
C.
Vol. at
0C. and
l m press.
Original cas
187.9
0.4180
2.2
79 18
After the explosion
149.3
0.3806
22
57 28
Hydrogen
Oxygen .
The whole 316.5 volumes of gas at the fifteenth ob-
servation contains, therefore, 29.18 oxygen and 287.32
218
LAWS OF THE
hydrogen. The original volume before the diffusion con-
sisting solely of hydrogen amounted to 385.2. For 29.18
volumes of oxygen which had entered 385.2 287.32
= 97.88 volumes of hydrogen had issued. The relation
between the volumes at the fifteenth observation was
P7 oo
therefore ' = 3.354, a result widely differing from
the value 3.995 required by the theory which has been
hitherto considered correct, but agreeing very closely
with the results which were found in the experiment
made with water.
In order to ascertain whether the relation of the
interchanging gases remains constant during a continued
diffusion, the volume of residual gas in the diffusion tube
was again accurately measured, the diffusion continued,
and another sample of gas collected after the twenty-fifth
observation. The analysis gave :
Vol.
Pres-
Temp.
Vol. at
C. and
sure.
C.
l m press.
Original gas ... ...
129.5
0.3615
-M
47.06
.Ai'tcr the explosion
38 5
273G
1 6
10 GO
II.
Hydrogen
Oxygen .
34.91
12.15
47.06
The volume of gas read off at the 16th observation
amounted to 192.3 volumes, and consisted, according to
analysis I, of 174.57 hydrogen and 17.73 oxygen. The
observation twenty -five made 46.2 minutes later gave a
volume equal to 145.8. According to analysis II this
DIFFUSION OF GASES. 219
volume contains 108.16 hydrogen and 37.64 oxygen. The
amount of hydrogen which had diffused out during these
46.2 minutes was therefore 174.57 108.16 = 66.41 vol-
umes ; and the amount of oxygen which had entered the
tube was 37.64 17.73 = 19.91. The relation between
the two interchanging volumes during this time was
/ J * -j
' = 3.336, a value agreeing very nearly with that
ly.t) i
found for the first period of the diffusion. From these
experiments we may conclude, that the volume of oxygen
which enters the tube, is to the volume of hydrogen which
issues from the tube, as 1 to 3.345, and that this proportion
remains constant during the whole course of the diffusion.
Having thus proved that within certain limits the
rate at which any gas traverses a porous diaphragm is
proportional,
1st to the difference of pressure to which the gas is
exposed above, and below the diaphragm, and
2ndly to a coefficient of friction which is dependent
upon the nature of the gas, and of the diaphragm,
we will now proceed to show that the phenomena of ga-
seous diffusion really depend upon the fact that these two
conditions are also applicable to the partial pressures of
mixed gases, restricted however within certain limits. In
order to prove this fact, the alteration of volume was
observed which a known amount of dry hydrogen under-
went (whilst the pressure was retained constant), when
a current of dry oxygen was passed over the diaphragm ;
and during this alteration the time \\as noted. Let us
suppose that the volume of hydrogen originally contained
in the diffusion tube was H Q under the pressure 1 ; and
that on the outside of the diaphragm an infinitely large,
or continually renewed atmosphere of oxygen was present,
220 LAWS OF THE
also under the pressure 1 ; and let us suppose that after
the lapse of the time t a volume of oxygen had entered
the tube, whilst the original volume of hydrogen had
diminished to H, so that HQ // under the pressure 1
represents the volume of hydrogen which had escaped,
whilst H -}- is the volume occupied by both gases.
Now as the volume of oxygen expands to the volume
H -\- 0, the pressure of the oxygen in the diffusion tube
amounts to . ( , and hence the difference of pres-
sure of the oxygen inside and outside the diaphragm is
represented by the equation
! H
- H + Q H+ 0'
and the amount of oxygen entering in the infinitely small
space of time dt is found from the expression:
(1) dO = H
in which t denotes the coefficient of friction in the
gypsum diaphragm, to be determined for hydrogen. On the
other hand, however, the volume 11 of hydrogen present,
has expanded into the volume H -\- 0, hence . .
represents the pressure which we must consider to be
the motive power in respect to the rate of issue of the
hydrogen. And as the diffusion apparatus was so ar-
ranged that the moment any hydrogen had diffused out
it was immediately carried away by the current of oxygen,
so that no other partial pressure was opposed to that of
the hydrogen within the tube, namely - . /o we find
that the volume of hydrogen which escapes in the time
DIFFUSION OF GASES. 221
dt is represented by the equation (bearing in mind that
the volume // decreases with increase of f)
H
in which 02 is again a coefficient dependent upon the
nature of the gas and diaphragm.
The first conclusion which is arrived at on comparing
these two equations (1) and (2), concerns the constant
relation which exists during the whole length of the dif-
fusion between the amount of oxygen dO entering at
every moment, and the amount of hydrogen dH issuing
at the same time, a relation which is represented by
a i
= y.
a,
In order to bring this explanation of the fundamental
principles of the phenomena of gaseous diffusion to the
test of experiment, we must endeavour to determine the
volumes of gas diffused after any finite time , together
with the observed volume in the diffusion tube H-\- 0= V
as function of the time. From equations (1) and (2) we
obtain
and hence by integration
-)- = consianl.
Now as the volume of hydrogen originally contained in
the diffusion tube was = H Q , and at the commencement
of the diffusion = 0, the unknown constant of the
former equation is found to be -, and we have
O
222 IAWS OF THE
By substituting the value = y (PI Q PI) in equation
(2) we obtain:
dPI = -
a 2 Pl
and therefore
-a 2 dt = (l --
and the integral of this, because when t = we have
also // = HQ , is
<M == (1 -r) (#0 -H) + yff<, log. e. .
As J/ = = - - we obtain by substituting this
value for PI:
(3) , = // - F+ y H, log. e.
If F, Fj , . . . , F n .denote the volumes in the diffusion
tube observed in the times t. ? 1? . . .. < B , we have:
(4) a, (, - = F- F, + y H log. e.
This equation No. 4 is best suited for the direct
experimental verification of the foregoing theory of dif-
fusion. The values of a 2 are calculated from the ob-
servational quantities, that is, for each reading of F,
Fj, . . ., F n , and the corresponding time tf, ^, . . ., t n \
the mean of these values of a^ is then substituted in the
equation, and thus the alteration of volume V n F n _|_i
in the spaces of time t n t nJrl calculated. If these cal-
culated values do not differ from the experimental results
by a larger quantity than that incurred in the unavoidable
errors of observation, we may presume that the equation
was correct, and hence that the theory upon which the
equation is founded is also true.
DIFFUSION OF GASES. 223
In order to conduct the observations under the
most favorable circumstances, hydrogen and oxygen
were used in the experiments as being the two gases
whose rates of diffusion are the most different. The
amount of gas contained in the gypsum diaphragm was
added to the quantity of dry hydrogen contained in the
tube , and care was taken that the oxygen which passed
over the diaphragm should be completely dried. The value
0.2989 given for y was that obtained in the foregoing
experiments by direct analysis , as the mean of the two
determinations ^ and found on pages 218
and 219.
The first observations are excluded from the cal-
culation because they are accompanied by errors of ob-
servation which can neither be eliminated nor allowed
for. The gypsum diaphragm at the beginning of the
experiment is completely filled with hydrogen; hence
diffusion begins on the surface of the diaphragm exposed
to the current of oxygen. This must necessarily cause
the phenomena of diffusion to be limited to the internal
mass of the gypsum, and hence the oxygen will only
gradually penetrate the porous substance, and after lapse
of a certain time reach the surface in contact with the
hydrogen. During the time in which the diffusion is
confined to the porous gypsum no alteration of volume
occurs in the diffusion tube, and thus the remarkable
fact is explained that on opening the tube a few moments
elapse before any diminution in the volume of the gas is
observed. From this cause, the observations for about
the first 48 seconds are inaccurate, but after lapse of this
time the gases have penetrated throughout the diaphragm
and the rise of the liquid in the tube proceeds regularly.
224 LAWS OF THE
For another reason we must also reject the last ob-
servations as incorrect. If the partial pressure of the
hydrogen diminishes so much towards the end of the
experiment, that the small differences of pressure within
and without the tube necessary for the observation, begin
to have a finite relation to this partial pressure, the ob-
servations, as we have shown, become untrustworthy.
Besides this, another error renders the latter observations
inaccurate, for, during the whole course of the observations
a small quantity of oxygen has entered the tube in con-
sequence of the slight difference of internal and external
pressure, and this quantity of oxygen pressed in is con-
tinually increasing, and causes the diffusion at the end of
the experiment to be retarded very much more than
would have been the case without this cause of error.
This uncertainty concerning the exactitude of the
later observations may be partly explained by the sup-
position that the simple relation between the partial
pressures and the rates of diffusion only strictly exists
within certain limits.
The following tables give the results of such a series
of observations made with the diffusiometer. The first
column contains the numbers of the observations; the
second the volume of gas read off, corrected according
to the table of capacity of the tube , and the capacity of
the porous diaphragm ; the third contains the time in
seconds at which the observations were made; the fourth
the values of a. 2 calculated from each single observation ;
the fifth the times which elapsed between each obser-
vation, and the last contains the same times calculated
from the mean value of a.
DIFFUSION OF GASES.
225
IT
III
IV
VI I VII
No.
of the
obser-
vation.
Observed
volume
V.
Cor-
responding
time in
seconds t.
f
Observed
tn M-l.
Calculated
t n t n +l
, = 0.4969
Diffe-
rence.
1
133.5 0.0
2
178.5 8.0
3
173.6 20.5
4
168.5 :U.o
5
163.5
48.0
G
158.0
62.0
0.5140
15.0
15.5
-4-0.5
7
153.6
77.0
o..".340
15.0
16.1
+ 1.1
8
148.5
92.0
0.4994
16.0
16.1
+ 0.1
9
143.5
108.0
0.5038
16.0
16.2
+ 0.2
i(r
138.5
124.0
0.5230
16.0
16.9
+ 0.9
11
133.5
140.0
0.4878
18.0
17.7
0.3
12
128.4
158.0
0.4922
18.0
17.8
0.2
13
123.4
17G.O
0.5500
17.0
18.8
+ 1.8
14
118.3
193.0
0.4529
21.0
19.1
1.9
15
1133
214. (I
0.4725
20.0
19.0
- 1.0
1C
108.4
234.0
0.4818
22.0
21.3
0.7
17
103.3
256.0
0.4778
23.0
22.1
0.9
18
19
20
98.3
93.3
88.4
279.0
302.0
328.0
0.5095
0.4765
0.4779
23.0
26.0
29.0
23.6
24.9
27.9
+ 0.6
- 1.1
1.1
21
22
83.4
78.4
357.0
391.0
23
24
73.4
68.3
428.0
474.0
25
63.2
553.0
2G
58.2
636.0
I
22G
LAWS OF THE
I
II
III
IV
V
VI
VII
No.
of the
obser-
vation.
Observed
volume
V.
Cor-
responding
time in
seconds t.
a,
Observed
t n tn+l.
Calculated
tn t n +l
^=0.6310
Diffe-
rence.
1
213.6
2
208.6
10
8
203.6
20
4
198.6
31
5
193.6
41
188.6
52
0.6347
12
12.1
-f-0.1
7
183.6
64
0.7165
11
12.5
+ 1.5
8
178.5
75
0.6421
12
12.2
-f 0.2
9
173.5
87
0.6653
12
12.7
+ 0.7
10
168.5
99
0.6775
12
12.9
-f 0.9
11
163.5
111
0.6310
13
13.0
0.0
' 12
158.6
124
0.6047
14
13.4
0.6
13
153.6
138
0.6800
13
14.0
-f 1.0
14
148.5
151
0.6353
14
14.1
+ 0.1
15
143.5
165
0.6532
14
14.5
+ 0.5
1C
138.5
179
0.6016
16
15.3
0.7
17
133.4
195
0.6514
15
15.5
+ 0.5
18
128.4
210
0.6346
17
16.1
0.9
19
123.4
227
0.6368
17
17.2
+ 0.2
20
118,3
244
0.6198
18
17.7
0.3
21
113.8
262
0.5440
21
18.1
2.9
22
108.4
283
0.6131
21
20.4
0.0
23
103.3
304
0.5693
24
21.7
2.3
24
'98.3
328
0.5793
26
23.9
-2.1
25
93.3
354
0.6345
2G
88.4
384
27
83.4
420
28
78.4
463
29
73.3
524
30
68.3
636
DIFFUSION OF GASES. 227
From these tables it is seen that the accordance
between the experimental and theoretical values is as
close as can be expected considering the possible ob-
servational errors. The agreement would have been still
more complete if the diffusion had not taken place so
quickly. For the theory assumes, that the gas entering
the diffusion tube, expands into the whole space of the
tube with a rapidity compared with which the rate of
passage of the gas through the diaphragm can be re-
garded as inappreciable. This strictly speaking is never
the case.
The condition required by the theory can be most
nearly complied with, by diminishing the rate at which
the gases traverse the diaphragm, and not allowing the
dimensions of the diffusion tube to be too large. This
retardation was effected in the following experiments
(from which the value of y employed in the former cal-
culations was obtained), by using a diaphragm of dense
gypsum of considerable length and small section.
The first part of this series of experiments was cal-
culated according to formula 3. A sample of gas was
taken between the first and second parts, from the
analysis of which on page 217 we see that the original
volume 192.3 with which the 16th observation is made
consists of 174.5 hydrogen to 17.8 oxygen. The formula
for the calculation of the second part of the analysis is
derived from the following considerations. If we suppose
that represents the amount of oxygen present in the
gas at the 16th observation, and H the amount of hy-
drogen present at the same time, and if thfc volumes of
these two gases present in a volume V observed at a
later time, be called and //, we have in the first
place :
15*
228 LAWS OF THE
H*-H ^.
O 0o ' " </i "
Further by substitution in former equation No. 2 the
value = + y (#0 JT ) we obtain :
=
and
(0 + ? #o) ~-
and tbe integral of tbis is:
(/ , f = (i _ y ) (J/ - - //) -f (0
If we substitute tbe value of
; F _ -
-
in tbis last equation, we have:
(5) a, /=
according to which formula the hitter observations from
16 to 2.5 are calculated.
DIFFUSION OF GASKs.
229
I
II JII IV
VI
!
No. of
Observed
Calculated
Observed
time in
the ob- ,
volume.
time in a,
minutes *<*-
servation.
minutes. , = 020702
1
385.2
o
2
v
y
3
-.'
4
?
y
5
366.2
13.0
0.2109
13.2
-|- 0.2
6
361.2
16.4 0.2118
16.7
-f- 0.3
7
356.2
20.0
0.2105
20.3
-{- 0.3
8
351.2
23.6
0.2098
23.9
4- 0.3
346.2
27.::
0.2033
26.7
0.6
10
341.2
31."
02081
31.1
-f- 0.1
11
336.2
34.7
0.2078
;54.7
0.0
12
99113
38.7
0.2056
:j8.3 0.4
13
326.3
42.2 . 0.2068
42.0 - 0.2
14
321.4
46.2 0.2054
45.7 _ o.:,
M
816.5
5fc3 .2"3!>
49.4 0.9
Interrupted in order to collect a sample of jius.
16
192.3
2 = 1.76<;9
17
184.2
7.4 1.7434
7.3
- 0.1
18
179.4
11.7 1.7699
11.7
0.0
19
174.6
16.1 1.7796
16.2
+ 0.1
20
169.8
20,5 1.7923 20 7 + 0.2
21
164.9
25.3 1.7855 25.6
+ 0.3
22
160.1
30.1 1.7808 j 30.3
+ 0.2
23
155.3
35.2 1.7682
35.2
0.0
24
150.6
40.5 1.7509
40.1
0.4
25
145.8
46. 2
1.7317
45.3
0.9
230 APPLICATION OF GASEOUS DIFFUSION.
In the former experiments the time which elapsed
until the original volume of gas had diminished 17.8 per
cent amounted to 1.4 minutes, in these experiments 36.2
minutes were required.
Oil comparing the results of this series of slower
diffusions with the more rapid diffusions in the preceed-
ing experiments a much closer approximation to the
theoretical numbers is perceived.
We must, however, not forget that a smaller value of
2 is found from the second part of the last series of ob-
servations than was obtained from the first part. This
shows that the diffusion -velocity is only approximately
proportional to the partial pressures, and that deviations
from this simple relation occur for partial pressures, just
as we have seen that the passage of gases through ca-
pillary tubes is only proportional to the total pressures
within certain definite limits.
We can now pass from these theoretical consider-
ations to the important application which can be made
of gaseous diffusion in many questions occurring in gaso-
metric investigations.
One of the most difficult questions which we are
called upon to decide, is, whether a given gas consists of
a single gas or of a mixture of several gases. If the pro-
ducts of combustion stand in no simple volumetric rela-
tion to one another there can be no doubt that we are
experimenting upon a mixture of gases, but the inverse
of this is by no means true , and we cannot always con-
clude from the simple relation existing between the vol-
umes of the products of combustion that a simple gas is
present, for we are acquainted with many chemical de-
compositions in which two or more gases are evolved in
their simple atomic proportions.
IN GASOMETRIC INVESTIGATIONS.
231
This difficulty is chiefly felt with mixtures of hydro-
gen and hydrocarbons, or generally with these numerous
mixtures of gases whose constituents cannot he separated
by absorbants or detected by any reagent.
In such cases two methods are available. The first
consists in submitting the gas to an absorptiometric ana-
lysis, and determining the volume of gas absorbed by a
volume of liquid, under various pressures and at a con-
stant temperature. If this amount of absorbed gas is
found to be proportional to the pressures, it must, accord-
Fig. 56.
ing to the laws of absorption, con-
sist of one gas and not of a mix-
ture of several.
In the second method, which is
equally as applicable as the first,
"^^ the gas is allowed to diffuse with
I' MiH atmospheric air, and on subsequent
analysis it is seen whether or not
any alteration in the relation be-
tween the products of combustion
has ensued. If ho alteration in this
relation is observed, we may con-
clude that the gas is not a mixture.
For this experiment the diffusion-
tube Fig. 56 is employed. The gra-
duated tube is closed at one end by
a plug of gypsum b from 8 to 10 mm
in thickness, and above this dia-
phragm the iron lid d can be screwed
tightly down, so that a very small
space is left between the upper sur-
face of the gypsum and the caout-
chouc plate covering the inside of the iron lid.
232
METHOD EMPLOYED.
This vessel, with the lid screwed down, is then filled
under mercury with the gas to be examined, and trans-
ferred from the mercurial -trough to a cylinder hy means
of the small iron spoon pp. After
the diffusion has continued for
some time, the lid being open
and the inner and outer level
of mercury kept equal during the
experiment, the lid is again shut,
the tube transferred back to the
trough with the spoon, and a
portion of the gas, now diluted
with air, filled into a eudiometer
for analysis.
As an example of the applica-
tion of diffusion in gas analysis,
we select the hydride of methyl
obtained on heating an acetate
with a hydrated alkali. It has
already been shown (p. 182) that
a simple analysis cannot decide
whether this consists of a mix-
ture or a chemical compound of
equal volumes of methyl and hy-
drogen.
The following experiment on diffusion , shows , in con-
firmation of the absorptiometric determination, that the
second supposition is the correct one, and that the methyl
contained in the gas is not simply mixed, but chemically
combined with the hydrogen.
DIFFUSION OF HYDRIDE OF METHYL. 233
The analysis of the gas before diffusion gave :
Vol.
Pres-
sure.
Temp.
C.
Vol. at
0C. and
1 press.
104.5
0.3123
5.7
32.0
Ditto -{- air
390.2
0.6009
5.7
229.7
4- oxvffen
429-0
O.G400
5.4
269.3
alter the explosion . . .
3G1.G
0.5711
5.4
202.5
carbonic acid ....
323.1
0.5388
5.8
170.2
39G.2
0.6136
5.7
238.1
after the explosion . . .
350-1
0.5G24
5.7
192.9
Combustible gas. Oxygen burnt. Carbonic acid formed.
32.0 : G5.9 : 32.3
1 : 2.08 : 1.01
Marsh gas alone, or a mixture of equal volumes of
methyl and hydrogen should give the relation of 1:2:1.
The same gas was allowed to diffuse into air until
the total volume had diminished from 205 to 170.
The analysis of the gas thus obtained gave :
Vol.
Pres-
Temp.
Vol. at
C. and
sure.
C.
l m press.
Original gas
126.8
0.3444
4.5
42.96
\- oxygen and air
280.6
0.4962
4.8
136.81
After the explosion ....
231.8
0.4473
4.8
101.90
Alter absorption of carbonic acid
201.8
0.4260
4.8
84.48
After admission of hydrogen . .
510.0
0.7359
5.2
368.30 .
Alter the explosion
422.9
0.6375
5.2
264.57
234 DIFFUSION OF GASES.
These observations cannot be calculated according
to the formula generally used because the relation be-
tween the constituents of the atmospheric air has altered
during the course of the diffusion. Another method must
therefore be employed.
If x denote the volume of the methyl-gas , y that of
the hydrogen, z that of the oxygen and n that of the ni-
trogen; and further if A represent the original volume
employed = x-\-y-\-z-}-n, C the carbonic acid formed
by the combustion, R the volume of residual oxygen found
on combustion with hydrogen after the removal of the
carbonic acid, and lastly N the volume of residual nitro-
gen and oxygen found after removal of the carbonic acid
we have:
n = N R
x = V C
_ A + 2R -f- 3 C n
y = A (oc -\- y 4- n).
/ \ i j i /
Hence experiment gives A =. 136.84, C = 17.42,
R = 34.58 and N 84.48. Whence we obtain:
Methyl ... 8.71
Hydrogen . . 8.78
Oxygen . . . 69.45
Nitrogen . . 49.90
136.84
A mixture of methyl arid hydrogen would before and
after diffusion exhibit different volumetric relations. As,
however, we find this not to be the case we have a direct
proof that the gas did not consist of a mixture of methyl
and hydrogen , but of a chemical compound of these two
gases.
COMBUSTION OF GASES. 235
PHENOMENA OF THE COMBUSTION
OF GASES.
\v hen a jet of gas burns in an atmosphere of another
gas, the phenomena occurring in the resulting flame are
of a most complicated nature, as the mixture of the com-
bining substances proceeds gradually, and hence the com-
position of each layer of the body of the flame is different.
In order to obtain a clear insight into the nature of com-
bustive phenomena we must commeDce with the study
of homogeneous flames, ensuing from the ignition of a
gaseous mixture of constant composition. In the follow-
ing pages we shall solely consider such simple cases.
One of the most important relations which we meet
with in the combustion of gases, regards
1) The heat of combustion. It is customary to de-
signate under this title the amount of heat which is
liberated by the chemical union of two or more bodies.
This amount of heat is independent of the time during
which the combustion occurs, but entirely depends upon
the chemical nature and quantity of the combining bo-
dies. In order to be able to measure the amount of the
heat evolved from the unit of weight of the substance , a
23(! HEAT OF COMBUSTION.
unit of heat is taken as the quantity required to raise
one part by weight of water from C. to 1 C. Thus
the number 2240 representing the heat of combustion of
sulphur signifies, that by the combustion of one part of
sulphur to sulphurous acid 2240 parts of water can be
raised from C. to 1 C., or what is the same thing, one
part of water heated from C. to 2240 C., when the
specific heat of water at all temperatures is considered
the same as at 0C, and when all evaporation is avoided.
We are indebted to Favre and Silbermann for a re-
cent research, carried out with all due precautions, upon
the heat of combustion, and as these results deserve more
reliance than the older experiments we shall make them
the starting point in the present chapter. Favre and
Silbermann found that,
Units of heat.
Hydrogen burning to water gave out .... 34462
hydrochloric acid gave out 23783
Carbon from "wood burning to carbonic oxide
gave out 2474
Ditto burning to carbonic acid gave out . . . 8080
Carbonic oxide burning to carbonic acid gave out 2403
Marsh gas burning to carbonic acid and water
gave out 13063
Olefiant gas burning to carbonic acid and water
gave out 11858
Sulphur burning to sulphurous acid gave out . 2240
Bisulphide of carbon burning to sulphurous and
carbonic acid gave out 3400
Sulphuretted -hydrogen burning to sulphurous
acid and water gave out 2741
By means of these numbers we can calculate the
heat of combustion of a gaseous mixture of known com-
HEAT OF COMBUSTION.
237
position. Let w , 0j, w? 2 , . . ., ? represent the amount of
heat liberated by each single constituent when the weights
of these constituents are # , g l , # 2 , . . ., r/ H , we have for
the heat of combustion W of the whole mixture the fol-
lowing expression:
^ WQ (Jo ~h Wi ffi + + w n <jn m
</o 4- g\ + - - + 9*
As an example of such a calculation I select the
heat of combustion of a mixture of gases which was
obtained from the shaft of a blast-furnace at Vecker-
hagen at depth of two feet under the surface of the fuel.
Composition Composition
according to according to
volume.
weight.
9
w
tog
Nitrogen
6078.0
7.6375
0.0
0.0
Garb, acid
874.0
1.7188
0.0
0.0
Garb, oxide
2629.0
3.2902
2403.0
7906.3
Hydrogen
196.0
0.0175
34462.0
603.0
Mnrsh gas
223.0
0.1596
13063.0
2084.9
1000.0 12.8236
Swg _ 10594.2
-Sf - 12*236-
Hence if the weight of gas issuing from the furnace
in the unit of time be represented by 6r, and if W stand
for its heat of combustion , we have the value G Wt for
the amount of heat lost in the time t in the unburnt
gases which escape.
As the average quantity of gases, of the composition
above given, issuing from the blast-furnace upon which
the experiments were made, amounted to 12 kilogrammes
per minute, the quantity of heat lost from this imperfect
combustion per hour is found to be
60 X 826 . 1 X 12 = 594792 units of heat.
238 HEAT OF COMBUSTION.
And as 1 kilogramme of coals is capable of heating 1 ki-
logramme of water up to 8080 C., the combustible mate-
594792
rials which issue unburnt are equal to 0/^0^ = 73.6 ki-
logrammes of coal per hour.
The weight of a given volume of gas is found from
table VIII. The first horizontal column contains the vo-
lumes in cubic - centimetres , the remaining columns the
weight in grammes of the corresponding volumes of the
gas mentioned at the beginning of the column. If, for
example, it is required to determine the weight of 1407.3
cubic - centimetres of carbonic acid we find from this
table, that
1000 cbc. weigh . . . 1.96663
400 : ... 0.78665
7 ... 0.01376
0.3 . . 0.00037
hence 1407.3 ... 2.76741
We must now distinguish between the heat of com-
bustion, and
2) The temperature of the combustion. This is the tem-
perature which exists in the interior of a burning mass,
and may be deduced from the heat of combustion when
we know the specific heat of the products of combustion
compared with that of water as unity. The following
values of the specific heats of the most important gases
required in these calculations, are taken from the latest
determinations of Regnault.
TEMPERATURE OF COMBUSTION. 239
Specific heats by constant pressure.
(Specific heat of water = 1.)
Oxygen 0.2182
Nitrogen 0.2440
Hydrogen 3.4046
Chlorine 0.1214
Carbonic oxide 0.2479
Carbonic acid 0.2164
Sulphuretted -hydrogen . . 0.2423
Sulphurous acid .... 0.1553
Hydrochloric acid . ... 0.1845
Olefiant gas 0.3694
Marsh gas 0.5929
Vapour of water .... 0.4750
Air 0.2370
If the constituents of a gaseous mixture weigh
h, . . ., g n before the combustion, and if theire respective
amounts of heat of combustion are W Q , u\ , . . ., iv n , the
heat of combustion of the mixture, as we have seen, is
jp #0 W -\~ 9l Wl -f" ' "t" 9n W n
that is , the mixture gives off an amount of heat capable
of raising 1 part by weight of water J! = H "degrees of
temperature. If the products of combustion were simply
water in the liquid state, this water would possess a tem-
perature jL The products of combustion are , how-
ever, gaseous bodies having a specific heat different from
that of water. Hence the temperature ^ will be to
the temperature of the gaseous products of combustion,
240 TEMPERATURE OF COMBUSTION.
inversely as the specific heat of water, to the specific heat
of the products of combustion; or (because the specific
'r-^
heat of water = 1) as the temperature v - divided by
the specific heat of the gaseous products. This is easily
found from the composition of the products of combustion.
If we represent by p Q , p\ , . . . , p n the weights of the con-
stituent parts of the gaseous products, and by s , S\T>-> *
their respective specific heats, we obtain for the value of
<S, the specific heat of the total product :
[ | [
and hence for the temperature of combustion T:
T
"
and, because the weight of the unburnt constituents (j
is equal to the sum of the constituents which have un-
dergone combustion Z?p, we have:
,_ 2gw
2 ps '
The 12 kilogr. or more correctly 12.8236 kilogr. of
gas, of the given composition, issuing from the blast - fur-
nace, requires for its complete combustion 2. 65817 kilogr.
of oxygen. These 2.65817 correspond to 11.46478 kilogr.
of air containing 8.80661 nitrogen. Hence we have the
composition of this gas before and after the com-
bustion.
TEMPERATURE OF COMBUSTION.
Before the combustion:
241
g
tp
wg
Nitrogen . .
16.444
Carbonic acid .
1.719
Oxygen . . .
2.658
Carbonic oxide
3.290
2403
7906.3
Hydrogen . .
0.018
34462
603.0
Marsh gas . .
0.160
13063
2084.9
lg = 24.289 Ztcg __ 10594.2
24.2884
S?= ir= 436018.
After the combustion:
Nitrogen . . 16.444
Carbonic acid 7.328
Aqueous vapour 0.517
JP*
0.2440 4.0123
0.2164 1.5858
0.4750 0.2456
= 24.289
Eps
5.8437
24.289
= S = 0.2406.
Hence the temperature of the combustion
f = -=1818.9 a
Zips S
This calculation is founded upon the assumption
that the specific heat of gases is not alterable with the
temperature as in the case with liquids and solids ; this
assumption has been proved by Reguault to hold good
for temperatures varying from 30 C. to -J- 225 C.,
and Clausius has shown the correctness of this view from
purely theoretical considerations.
The following table gives the temperature of com-
bustion for several gases, calculated according to the
preceeding method.
16
242 TEMPERATURE OF COMBUSTION
Hydrogen (burned with chlorine) . . 3532 C.
Carbonic oxide (burned with oxygen) 7067 C.
Marsh gas 7851 C.
Hydrogen 8061 C.
Olefiant gas 9187 C.
Carbonic oxide (burned with air) . . 3042 C.
Marsh gas 5329 C.
Hydrogen 3259 C.
Olefiant gas 5413 C.
These numbers represent the temperatures which the
various gases attain on combustion with exactly the re-
quisite amount of chlorine, oxygen, or air, supposing that
the inflamed gases can freely expand as is the case in an
open flame. If, on the contrary, the combustion occurs
in a closed space, under circumstances in which the vol-
ume, and not the pressure of the gas remains constant,
the temperature of the combustion will be totally different.
In order to calculate the temperature in this case, we
must substitute the value of the specific heats for con-
stant volume for those by constant pressure. If we as-
sume, in accordance with Dulong's experiments, that the
relation of the specific heats by constant pressure and by
constant volume is 1.421 for air, we obtain the specific
heat c by constabt volume, for any given gas, from the
specific heat c v under constant pressure, from the follow-
ing equation in which s represents the specific gravity of
the gas compared with air as unity:
0.070216
G = 6*1
S
The specific heats for constant volume and varying
pressure are thus found for the preceeding gases :
EXPLOSIVE .FORCE OF GASES. 243
Oxygen 0.1547
Nitrogen 0.1717
Hydrogen 2.3910
Chlorine 0.0928
Carbonic oxide . . . . 0.1753
Carbonic acid 0.1702
Sulphuretted-hydrogen . . 0.1826
Sulphurous acid .... 0.1236
Hydrochloric acid .."j'. 0.1288
Olefiant gas . .: j . , r,, J . 0.5204
Marsh gas ,**.,..',:* '*Q. $i 0.2425
Aqueous vapour .... 0.3621
Air 0.1668
By means of these values we obtain the following
temperatures when the gases are burned in closed vessels.
Hydrogen with chlorine . . . 5059 C.
Carbonic oxide with oxygen . 8986 C.
Marsh gas 10183 C.
Hydrogen 10575 C.
Olefiant gas. 11853C.
Intimately connected with these temperatures of
combustion is
3) The explosive force of gases. When the tempe-
rature of the combustion and the volume of the pro-
ducts formed thereby are known, we can arrive at certain
conclusions regarding the amount of the mechanical action
which accompanies the combustion of explosive gaseous
mixtures. For this purpose we merely require to cal-
culate, firstly, the alteration of volume which the unit
amount of the unburned gas undergoes in consequence
of the combustion, and, secondly, the heat evolved during
the process.
16*
244 EXPLOSIVE FORCE OF GASES.
For instance, one volume of a gaseous mixture of
2/3 vol. carbonic oxide and J /3 v l- oxygen gives on com-
bustion 2 /3 v l- carbonic acid. If the gas cannot expand
during this combustion it is heated (according to the
calculations of the temperature of combustion), to 8986 C.
2 /3 vol. carbonic acid occupies at 8986 C. the volume
2/ 3 (1 -f 0.00366 X ^986) = 22.59. AS the gas could
not expand, these 22.59 volumes are compressed into a
volume equal to 1. Hence, according to Mariotte's law,
if the gas before the combustion was measured at 0C.,
and under a pressure of one atmosphere, the pressure
exerted during the combustion on the inner surface of a vessel
containing the gas must have been 22.59 atmospheres.
In this way, the pressures which the following mix-
tures of detonating gases exert upon their inclosing sur-
faces are calculated, supposing that the gases are com-
.pletely burned in closed vessels at 0C., and under the
normal atmospheric pressure.
1. Hydrogen with chlorine . . . 19.5 atmospheres
2. Carbonic oxide with oxygen . . 22.6
3. Hydrogen 26.5
4. Marsh gas 38.3
5. Olefiant gas 44.4
6. Ditetryl 88.8
Experience teaches us, in accordance with this cal-
culation, that the detonating gases 1 and 2 can be ex-
ploded without danger in thin flasks, that No. 3 requires
somewhat more substantial vessels, and that even narrow
eudiometers of thick glass are shattered by exploding 4
and 5, whilst it is scarcely possible to obtain a eudio-
meter strong enough to resist the shock ensuing from
the combustion of ditetryl. Hence we see that in gas
EXPLOSIVE FORCE OF GASES. 245
analyses it is always necessary before combustion to dilute
with some indifferent gas any one which contains its con-
stituents in a very condensed state. If all these ex-
plosive gases be detonated in a thin flask surrounded by
cloths and held in the hand scarcely any shock is felt-
when the flask is broken by explosion with the gases
1 and 2 ; with Nos. 3 and 4 the detonation is more per-
ceptible; and with 5 and 6 the explosion takes place in
so violent a manner that the shock can scarcely be
endured.
In all these phenomena, we must remember that it
seldom happens that the total pressure of the exploding
gases comes into play. If the combustion commences at
one point, a certain time is required before it is trans-
mitted throughout the mass. This time appears to depend
upon the chemical nature of the mixture undergoing
combustion. Thus the combustion of carbonic oxide can
be followed by the eye, whilst this is not possible with
other detonating gases.
If a column of detonating gas be ignited at its upper
extremity, the combustion does not reach the lower end
of the column until a certain quantity of heat has been
lost by radiation and conduction. When the detonating
gas is diluted with an indifferent gas nearly up to its
limit of inflamability . a ball of fire is frequently seen to
start from the point of ignition and to move slowly
downwards to the lower end of the column of gas. In
this case, the combustion at the top of the column is at
an end, whilst at the bottom the action is still proceeding.
The combustibility of any detonating gas is therefore
diminished by addition of an indifferent gas not only
because the temperature of the combustion becomes lower,
but also because the rate of transmission of the com-
246 TEMPERATURE OF IGNITION OF GASES.
bustion decreases. Hence we see, that the total pressure
can be exerted only when the combustion of the whole
mass takes place simultaneously. This fact explains
the singular fact that the same chlorous acid accord-
ing as it is ignited, or explodes spontaneously, either
gives a slight report, or else detonates most violently,
producing extraordinary mechanical effects; and that a
glass containing a mixture of chlorine and hydrogen is
shattered when the gas is exposed to the direct sun-
light, whereas if an electric spark be passed through the
mixture the vessel remains unbroken.
4) Temperature of ignition of gases. If an explosive
mixture of gases is diluted with a large quantity of a
non - combustible gas, a limit is reached, beyond which
the mixture ceases to be capable of ignition. This
limit can be so closely approached that the smallest
addition of a non -combustible gas is sufficient to cause
a gaseous mixture which was before perfectly infiamable
to become as perfectly non -combustible.
A gas which has thus become non-inflamable regains
its combustibility if it is prevented from expanding freely
during the ignition, or when its temperature has been
increased. The limit of dilution at which this sudden
check is given to the inflamability is essentially dependent
upon the nature of the gases used as diluents.
The following experiments show the influence which
the presence of oxygen, hydrogen or carbonic acid exert
upon the limits of inflamability of the oxyhydrogen de-
tonating gas *.
* All the combustions detailed in these experiments were con-
ducted in closed eudiometers, and hence in the calculations
founded upon these experiments , the specific heats of the
gases for constant volumes are employed.
TEMPERATURE OF IGNITION OF GASES.
Non-inflamable mixture.
247
VOL Pres -
sure.
Temp., VoLat
1 0C. and
l m press.
Original volume of oxygen . .
Alter addition of hydrogen . .
Alter passage of spark ....
194.0
202.9
203.5
0.7111
0.7203
0.7173
6.3
5.7
5.7
137.81
146.15
145.97
Inflamable mixture.
Original volume of oxygen . .
After addition of hydrogen . .
Alter passage of spark ....
191.0
201.7
192.8
0.708G
6.7172
0.7000
5.8
5.8
5.8
135.54
144.66
134.96
Non-inflamable mixture.
Original volume of hydrogen . .
Alter addition of oxygen . . .
189.2
200.0
0.7070
0.7"173
6.0
6.0
133.8
t !34.5
Inflamable mixture.
Original volume of hydrogen . .
After addition of oxygen . . .
188.2
200.4
0.7031
0.7164
7.0
7.0
132.3
143.2
Non-inflamable mixture.
Original volume carbonic acid
Alter addition of detonating gas
122.4
156.9
0.6780
0.7128
5.7
5.7
81.29
109.39
Inflamable mixture.
Original volume carbonic acid
After addition of detonating gas
122.4
15G.1
123.9
0.6780
0.7191
0.6807
5.7
5.3
5.5
81.29
110.12
82.73
248 LIMIT OF INFLAMABILITY.
These experiments show:
i.*
That 1 vol. of deton. gas with 2.82 carbonic acid is inflamable
1 3.37 hydrogen
1 9.35 oxygen
II.
That 1 vol. of deton. gas with 2.89 carbonic acid is non - inflamable
1 >, 3.93 hydrogen
1 10.08 oxygen
The temperature of combustion calculated for the
first inflamable mixture of one volume of detonating gas
to 2.82 volumes of carbonic acid, amounted to 18088 C. ;
the same for the non - inflamable mixture with 2.89 vol-
umes of carbonic acid is found to be 17724C.
In order to understand the processes which occur
on these combustions, let us suppose a column of mixture
Fig. 58. No. 1 at 0C. divided into a number of
equal -sized infinitely thin layers a, a^
ct 2 , . . . We shall find that the following
phenomena occur during the ignition of
these layers, not considering for the mo-
ment the other physical relations.
As soon as the first layer a is raised,
by any outward cause, to the temperature
of ignition x, the combustion occurs, ac-
companied by an increase of temperature
of the layer from x to x -f- 18088, in consequence of
the heat of combustion. This temperature is communi-
cated to the adjacent equally large, infinitely thin layer
i , until an equilibrium is established , and each layer
x -f 180808
has arrived at the temperature ' . Owing to
LIMIT OF INFLAMABILITY. 249
conduction and radiation, and by the alteration of the
capacity of heat of the products of combustions, these
layers must lose a certain quantity of the amount
of heat they originally contained. The temperature of
the layers a and a t is therefore
)
- 1808Q8 \
2 Jr
As this temperature is sufficient to ignite the layer
ai it must certainly be as great if not greater than x.
If we repeat these considerations in the case of the
second mixture of 1 vol. detonating gas to 2.89 of car-
bonic acid, we obtain for the temperature of the layer a v
the value
17724\
/ J_\ /*
\ n}\
As, however, this mixture did not ignite, and therefore
the combustion was not transmitted to the layer j . the
/ 1 \ ( x _l_ 1772<4\
value (1 ) ( - o~ ) mu t be smaller than x.
The difference of these two temperatures is :
Hence, if we add the temperature (l - -J 182 to
the temperature ( 1 -J (- ^ -j the value of a-,
that is of the temperature of ignition, is attained or
exceeded.
250 LIMIT OF INFLAMABILITY.
The gaseous mixture is, therefore, not inflamable
without this additional temperature f 1 - j 182, but
with this increased amount of heat it becomes com-
bustible. As this number less than 182 may be con-
sidered to be infinitely small when compared to the tem-
perature of ignition #, upwards of 1000, we may assume,
without any perceptible error, that the limit of com-
bustibility, or what in this case is the same, viz the tem-
perature of ignition, is equal to
/ iw,+.m*4x
V 1 T/ \ 2 /
Hence we have:
or
x = l 17906.
A similar calculation applied to the remaining ex-
periments gives the following results, for the various
temperatures of ignition:
1) of deton. gas and hydrogen (l --- ) 21168 = x
\ ^o /
2) carb. acid (l -- -) 17906 = x l
\ MI /
3) oxygen . (l - -L) 857<>3 = ^
\ "2 /
The variations seen in these three numbers may arise
from three different causes. Either, in the first place,
the temperature of ignition x is a invariable quantity, and
hence the coefficient of loss of heat must vary with
n
PECULIAR ACTION OF DILUENTS. 251
the nature of the gas added in excess ; or , in the second
place, the coefficient - - is constant, and the temperature
of ignition is altered by the mere presence of the diluent
which does not enter into combination; or, thirdly, both
these causes act together.
Let us now examine whether the difference between
the calculated temperatures can be explained by the
first supposition , viz : that the temperature of ignition x
has a constant value. If x = x l = x 2 we have :
and hence
-<-<-.
n-2 n^ * TI O
The fraction th of the total increase of temperature
which is lost by radiation, conduction &c. is therefore
less in the oxygen mixture No. 3, than in the carbonic
acid mixture 2, and less in this latter case than in the
hydrogen mixture 1. Let us now see if this be really
the case.
In the first place , an explanation of the loss of tem-
perature may be given in the fact, that the specific heat
of the products of combustion contained in layer a, is
different from the specific heat of the gases in layer !
which are not yet burned. The relation between the cal-
culated specific heats of the gases which have, and which
have not undergone combustion, is given in the following
table,
In the oxygen mixture . . (3) as 1 : 1.009
carbonic acid mixture (2) 1 : 1.020
hydrogen mixture . (1) 1 : 1,023
252 DIATHERMANOUS PROPERTIES OF GASES
This relation is certainly in the direction <<-
n% ^ r f*i n
which the theory requires, but the difference between
each value is so small that its influence upon the tem-
perature of ignition is inappreciable, and may be con-
sidered to fall within the limits of observational error.
The great differences observed in the temperatures of
ignition do not therefore arise from this relation of the
specific heats.
Another much more important source of unequal
cooling , exists in the radiation and conduction of heat
in the various gases. If the radiation and conduction of
heat proceeds more rapidly in one gas than in another,
the loss of heat accompanying the equalisation of tem-
perature in layers a and a must necessarily vary during
the combustion. As no data exist concerning the dia-
thermanous properties of gases, I have endeavoured to
determine the question by direct experiment.
For this purpose, a galvanic current of gradually
increasing intensity was passed through two platinum
wires of equal length and thickness a % , Fig. 59 , one of
which a was surrounded by carbonic acid, and the other
% with oxygen, in the two glass tubes AA^ As soon as
the current had attained, a certain intensity, the first
wire a become red-hot, and after the strength of the
current had been still further increased, the first symptoms
of glow were observed in the wire a surrounded by
oxygen ; and this . latter wire was always visibly less
heated than the former. If the direction of the current
was reversed, or the contents of the tubes changed, the
glow was always first observed in the atmosphere of
carbonic acid. Now as the same current passing through
two wires of equal dimensions, produces in each an equal
INFLUENCE OF DILUENTS.
253
amount of heat , and as the capacity of heat of oxygen
and carbonic acid is almost exactly the same under equal
pressure, the only reason which can be assigned for the
Fig. 59.
fact that the wire becomes always first red-hot in the
carbonic acid, is that this gas gives off its heat by ra-
diation and conduction with greater difficulty than oxygen
gas. Accordingly the loss of heat - in the carbonic
711
acid mixture (2) ought to be less than the loss in
n 2
the oxygen mixture (3) if the equation x = x l == x 2 is
correct. In reality, however, we find from the experiment
that <~ ; hence we must consider that the sup-
2 - ni
position that x is invariable is not correct, and we
may fairly conclude , that the temperature of ignition
of a gaseous mixture varies according to the nature of the
gases present, whether they take pa ft in the chemical action
or not.
254 IMPORTANT BEARINGS OF THESE
A knowledge of these remarkable phenomena ne-
cessitate a consideration of the mode of action of affinity
from a new point of view. For, according to these ex-
periments, we see that the temperature of ignition, or
the point at which the chemical attraction of the mole-
cules is so increased that combination can take place, is
not only dependent upon the relative attractions of the
molecules undergoing combination, but also upon those
particles which are present but do not take any active
part in the decomposition. Hence we are obliged to
admit that chemical affinity is the resultant of the at-
tractive forces exerted by all the molecules within the
sphere of the chemical attraction, whether these mole-
cules take part in the chemical action or not. By this
supposition alone can we satisfactorily account for the
observed phenomena.
If a mixture of one part of detonating gas with 2.85
parts of carbonic acid is raised to a temperature some-
what below that necessary to ignite the detonating gas, the
gas will immediately explode if the carbonic acid be re-
placed by oxygen; although neither the carbonic acid
nor the oxygen take any part in the chemical combination.
From these observations we cannot doubt that the
so called catalytic decompositions may be explained in
the same way; and that, far from depending upon any
extraordinary causes, they are simply the common effects
of affinity. Just as a volume of detonating gas in the
sphere of attraction of molecules of carbonic acid is not
combustible at a given temperature, but when in the
sphere of the molecules of oxygen the gas becomes com-
bustible at the same temperature, we also find that the
elements of peroxide of hydrogen are retained combined
in the sphere of attraction of the atoms of water, but do
FACTS ON THE ACTION OF AFFINITY. 255
not remain combined in the sphere of attraction of the
atoms of black -oxide of manganese or metallic platinum.
Nor should we be astonished at the fact, that a small
quantity of platinum is able to decompose an unlimited
amount of peroxide of hydrogen. For wherever a piece
of platinum touches peroxide of hydrogen the affinity in
the nearest layer is so weakened that the peroxide in
this layer, but only in this layer, decomposes into oxygen
and water. The chemical action of the platinum here
ends; and it is only when the products of decomposition
thus formed, are removed by foreign forces, such as gra-
vitation, capillarity, expansion &c., and by means of these
foreicfn forces new peroxide of hydrogen brought in contact
with the platinum, that the phenomenon is repeated.
Hence it is seen, that the catalytic action produced
by the platinum or oxide of manganese, is not equi-
valent to an unlimited amount of labour, but that for
every decomposition effected, an equivalent amount of
force is absorbed, just as in the case of^a weight raised
by a falling body, a force is expended exactly equivalent
to the work done.
I have just shown that the temperature of ignition
of two chemically different molecules of a homogeneous
gaseous mixture, depends upon the total number of mo-
lecules lying within the sphere of attraction, and that
therefore, this temperature must be altered by the presence
of other particles of the same or different material pro-
perties. This catalytic action which the excess of mo-
lecules present taking no part in the decomposition exert
upon the combining molecules, is seen in a most remarkable
manner in the volumetric relation between the products
formed by the combustion, and brings to light a singular
law which appears to be of fundamental importance in
256 SIMPLE VOLUMETRIC RELATION
the mode of action of affinity. If, namely the particles
a of a homogeneous gaseous mixture have the choice of
combination between the particles b and c of two other
gases present in excess, a certain equilibrium ensues
between the attractions of all the particles , so that the
compounds (a -\- b) and (a -f- c), formed by the union
of a with b and c, stand in a simple relation to one an-
other, dependent upon the amount of the particles re-
maining uncombined, and undergoing discontinuous al-
teration on gradual increase of these- particles. Suppose,
for instance, that we have a gaseous mixture of 30 atoms
of oxygen, 30 of hydrogen, and 119 atoms of carbonic
oxide, the proportion between the atoms of carbonic acid,
and water, which can be thus combined is represented
by n HO and 30 -- n CO 2 when n represents all the
whole numbers from to 30. That is :
either 30 atoms water to atoms carbonic acid
r 29 1
1 9Q
ii ii ii ii u *' 11 11 11
11 11 n 11 ^^ 11 11 11
According to the preceeding law, however, only those
cases of these 31 are possible in which 1, 2, 3 atoms of
the one product are formed together with 1, 2, 3, 4 . . .
of the other. In the experiment before us, the atomic
relation between the water and carbonic acid formed, is
as 1 : 1. If the volume of carbonic oxide present be
gradually diminished, the relation of HO : CO 2 suddenly
changes to that of 2 HO : CO 2 as soon as the proportion
of carbonic oxide has sunk to 86 atoms.
BETWEEN THE PRODUCTS OF COMBUSTION. 257
The following experiments, conducted with electro-
lytic detonating gas and carbonic oxide, may serve to
illustrate this law.
EXPERIMENT 1.
Vol.
Pres-
Temp.
Vol. at
0C. and
sure.
C.
l m press.
1 1
Electrolytic detonating gas . .
42.7
0.6232
22.2
24.G1
After addition of carbonic oxide
132.0
0.7350
22.2
89.73
Employed for combustion:
Volume of gas employed . . .
After the combustion ....
145.8
124.1
0.7338
0.7318
22.3
22.4
98.92
83.92
EXPERIMENT 2.
Electrolytic detonating gas . .
After addition of carbonic oxide
After the explosion
123.6
261.1
220.1
ENT
0.3210
0.4527
0.4130
3.
3.4
3.3
3.0
40.04
116.79
89.99
EXPERIM
Electrolytic detonating gas . .
After addition of carbonic oxide
57.6
130.3
0.6422
0.7085
22.4
22.5
34.19
85.32
Employed for th<
Gas employed
2 coml
119.5
87.2
>ustior
0.7293
0.7293
L:
22.5
22.5
80.52
58.76
After the combustion ....
EXPERIMENT 4.
Electrolytic detonating gas . .
After addition of carbonic oxide
After the explosion . .
120.4
193.0
134.7
0.3084
0.3806
0.3308
5.3
4.7
3.8
17
36.43
72.21
43.94
258
SIMPLE VOLUMETRIC RELATION
EXPERIMENT 5.
Vol.
Pres-
Temp.
Vol. at
C. and
sure.
C.
l m press.
Electrolytic detonating gas . .
104.0
O.G713
22.3
64.55
After addition of carbonic oxide
150.0
0.7358
22.5
101.98
Employed for the combustion:
113.4
58.2
0.7234
0.6667
22.0
22.7
After the combustion ....
EXPERIMENT G.
Electrolytic detonating gas . .
After addition of carbonic oxide
After the combustion
121.3
152.9
67.2
ENT
0.3182
0.3523
0.2766
7.
3.0
2.6
2.8
EXPERIM
Electrolytic detonating gas . .
After addition of carbonic oxide
After the explosion
123.4
147.4
61.3
ENT
0.3229
0.3436
0.2589
8.
2.4
2.3
1.9
EXPERIM
Electrolytic detonating gas . .
After addition of hydrogen . .
After addition of carbonic oxide
65.7
98.0
151.9
0.6321
0.6645
0.7165
22.7
22.8
23.0
Employed for the combustion:
Gas employed . 168.6 0.7194 23.0
After the combustion . .
112.4
ENT
0.7206
9.
23.0
EXPERIM
Electrolytic detonating gas . .
After addition of carbonic oxide
119.3
139.9
52.9
0.3004
0.3207
0.2421
6.5
7.0
5.3
BETWEEN THE PRODUCTS OF COMBUSTION. < 259
According to these analyses the composition of these
mixtures which underwent combustion was the following :
Expt. 1. Expt. 2. Expt. 3. Expt. 4. Expt. 5.
Vol. of oxygen .... 100.0 100.0 100.0 100.0 100.0
hydrogen . . . 200.0 200.0 200.0 200.0 200.0
carhonic oxide 793.8 575.0 448.6 294.7 174.0
Expt. 6. Expt. 7. Expt. 8. Expt. 9.
Vol. of oxygen .... 100.0 100.0 100.0 100.0
t hydrogen . . . 200.0 200.0 370.3 200.0
carbonic oxide 119.3 80.7 315.1 74.0
In order to calculate the quantity of hydrogen and oxy-
gen which combined with these 100 volumes of oxygen in
the foregoing mixtures, we only require to know the vol-
ume of gas which has disappeared on exploding the various
mixtures, as found from the experiments. If we call this
contraction C, and the amount of oxygen burnt 100 = 0,
we find the volume of carbonic acid formed c, and that
of the aqueous vapour w produced from the following
equation :
3 C = c,
C = w.
The following values for and C are obtained from
the experiments:
Expt. 1.
Expt. 2.
Expt. 3.
Expt. 4.
Expt. 5.
.
. 100.0
100.0
100.0
100.0
100.0
c .
. 165.7
200.72
202.3
232.7
250.0
Expt. 6.
Expt. 7.
Expt. 8.
Expt. 9.'
.
. 100.0
100.0
100.0
100.0
c .
251.7
261.2
260.9
266.5
Hence the following amounts of carbonic acid and
water in the various experiments are calculated:
17*
2GO
SIMPLE VOLUMETRIC RELATION.
Expt. 1.
Expt. 2.
Expt. 3
. Expt. 4.
Expt. 5.
Carbonic
acid
67
50
51
34
25
Aqueous
vapour .
33
50
49
66
75
100
100
100
100
100
Expt. 6.
Expt. 7.
Expt. 8
. Expt. 9.
Carbonic
acid . .
24
19
20
17
Aqueous
vapour .
76
81
80
83
100 100 100 100
The numbers in the second horizontal division of
the following table represent the relation between car-
bonic acid and water which must ensue if the compound
in the first division is formed by the combustion :
Expt. 1. Expt. 2. Expt. 3. Expt. 4. Expt. 5.
HO 2 CO 2
HO CO 2
HO CO 2
2 HO CO 2
2 HO CO 2
Carbonic acid
67
50
50
33
25
Aqueous vapour
33
50
50
G7
75
100
100
100
100
100
Expt. 6. Expt. 7. Expt. 8. Expt. 9.
3 HO CO 2
4 HO CO 2
4 HO CO 2
5 HO CO 2
Carbonic acid
25
20
20
17
Aqueous vapour
75
80
80
83
100
100
100
100
The proportion between the constituents of these simple
formulae corresponds almost exactly with the volumetric
relation found in the products of combustion which the
BETWEEN THE PRODUCTS OP COMBUSTION. 201
oxygen formed, when divided between the two gases pre-
sent in excess.
In each of the nine mixtures which we have con-
sidered, a regular system of molecular attractions has
been formed as the resultant of the respective attractions
of the non- combustible, as well as of the combustible
particles ; and this system of attractions is of such a kind
that the atoms exposed to it arrange themselves so as
to form the six most simple hydrates of carbonic acid.
TABLES
FOR
THE CALCULATION OF ANALYSES.
TABLE OF THE TENSION OF THE VAPOUR OF WATER. 265
I.
Table of the tension of aqueous vapour for temperatures
from 2 to -j-35C., according to Regnault.
C. Tension.
C.
Tension.
C.
Tension.
C.
Tension.
2.0
3.955
-f-2.0
mm
5.302
-{-6.0
mm
6.998
-4- 10.0
mm
9.165
1.9
3.985
2.1
5.340
6.1
7.047
10.1
9.227
1.8
4.016
2.2
5.378
6.2
7.095
10.2
9.288
1.7
4.047
2.3
5.416
6.3
7.144
10.3
9.350
1.6
4.078
2.4
5.454
6.4
7.193
10.4
9.412
1.5
4.109
2.5
5.491
6.5
7.242
10.5
9.474
1.4
4.140
2.6
5.530
6.6
7.292
10.6
9.537
1.3
4.171
2.7
5.569
6.7
7.342
10.7
9.601-
1.2
4.203
2.8
5.608
6.8
7.392
10.8
9.665
1.1
4.235
2.9
5.647
6.9
7.442
10.9
9.728
1.0
4.267
3.0
5.687
7.0
7.492
11.0
9.792
0.9
4.299
3.1
5.727
7.1
7.544
11.1
9.857
0.8
4.331
3.2
5.767
7.2
7.595
11.2
9.923
0.7
4.364
3.3
5.807
7.3
7.647
11.3
9.989
0.6
4.397
3.4
5.848
7.4
7.699
11.4
10.054
0.5
4.430
3.5
5.889
7.5
7.751
11.5
10.120
0.4
4.463
3.6
5.930
7.6
7.804
11.6
10.187
0.3
4.497
3.7
5.972
7.7
7.857
11.7
10.255
0.2
4.531
3.8
6.014
7.8
7.910
11.8
10.322
0.1
4.565
3.9
6.055
7.9
7.964
11.9
10.389
0.0
4.600
4.0
6.097
8.0
8.017
12.0
10.457
+ 0.1
4.633
4.1
6.140
8.1
8.072
12.1
10.526
0.2
4.667
4.2
6.183
8.2
8.126
12.2
10.596
0.3
4.700
4.3
6.226
8.3
8.181
12.3
10.665
0.4
4.733
4.4
6.270
8.4
8.236
12.4
10.734
0.5
4.767
4.5
6.313
8.5
8.291
12.5
10.804
0.6
4.801
4.6
6.357
8.6
8.347
12.6
10.875
0.7
4.836
4.7
6.401
8.7
8.404
12.7
10.947
0.8
4.871
4.8
6.445
8.8
8.461
12.8
11.019
0.9
4.905
4.9
6.490
8.9
8.517
12.9
11.090
1.0
4.940
5.0
6.534
9.0
8.574
13.0
11.162
1.1
4.975
5.1
6.580
9.1
8.632
13.1
11.235
1.2
5.011
5.2
6.625
9.2
8.690
13.2
11.309
1.3
5.047
5.3
6.671
9.3
8.748
13.3
11.383
1.4
5.082
5.4
6.717
'9.4
8.807
13.4
11.456
1.5
5.118
5.5
6.763
9.5
8.865
13.5
11.530
1.6
5.155
5.6
6.810
9.6
8.925
13.6
11.605
1.7
5.191
5.7
6.857
9.7
8.985
13.7
11.681
1.8
5.228
5.8
6.904
9.8
9.045
13.8
11.757
1.9
5.265
5.9
6.951
9.9
9.105
13.9
11.832
266
TABLE OF THE TENSION
c.
Tension.
C.
Tension. C.
Tension. C.
Tension.
-}- 14.0
ll!908
+ 18.0
mm
15.357
+ 22.0
mm
19.659
+ 26.0
mm
24.988
14.1
11.986
18.1
15.454
22.1
19.780
26.1
25.138
14.2
12.064
18.2
15.552
22.2
19.901
26.2
25.288
14.3
12.142
18.3
15.650
22.3
20.022
26.3
25.438
14.4
12.220
18.4
15.747
22.4
20.143
26.4
25.588
14.5
12.298
18.5
15.845
22.5
20.265
26.5
25.738
14.6
12.378
18.6
15.945
22.6
20.389
26.6
25.891
14.7
12.458
18.7
16.045
22.7
20.514
26.7
26.045
14.8
12.538
18.8
16.145
22.8
20.639
26.8
26.198
14.9
12.619
18.9
16.246
22.9
20.763
26.9
26.351
15.0
12.699
19.0
16.346
23.0
20.888
27.0
26.505
' 15.1
12.781
19.1
16.449
23.1
21.016
27.1
26.663
15.2
12.864
19.2
16.552
23.2
21.144
27.2
26.820
15.3
12.947
19.3
16.655
23.3
21.272
27.3
26.978
15.4
13.029
19.4
16.758
23.4
21.400
27.4
27.136
15.5
13.112
19.5
16.861
23.5
21.528
27.5
27.294
15.6
13.197
19.6
16.967
23.6
21.659
27.6
27.455
15.7
13.281
19.7
17.073
23.7
21.790
27.7
27.617
15.8
13.366
19.8
17.179
23.8
21.921
27.8
27.778
15.9
13.451
19.9
17.285
23.9
22.053
27.9
27.939
16.0
13.536
20.0
17.391
24.0
22.184
28.0
28.101
16.1
13.623
20.1
17.500
24.1
22.319
28.1
28.267
16.2
13.710
20.2
17.608
24.2
22.453
28.2
28.433
16.3
13.797
20.3
17.717
24.3
22.588
28.3
28.599
16.4
13.885
20.4
17.826
24.4
22.723
28.4
28.765
16.5
13.972
20.5
17.935
24.5
22.858
28.5
28.931
16.6
14.062
20.6
18.047
24.6
22.996
28.6
.29.101
16.7
14.151
20.7
18.159
24.7
23.135
28.7
29.271
16.8
14.241
20.8
18.271
24.8
23.273
28.8
29.441
16.9
14.331
20.9
18.383
24.9
23.411
28.9
29.612
17.0
14.421
21.0
18.495
25.0
23.550
29.0
29.782
17.1
14.513
21.1
18.610
25.1
23.692
29.1
29.956
17.2
14.605
21.2
18.724
25.2
23.834
29.2
30.131
17.3
14.697
21.3
18.839
25.3
23.976
29.3
30.305
17.4
14.790
21.4
18.954
25.4
24.119
29.4
30.479
17.5
14.882
21.5
19.069
25.5
24.261
29.5
30.654
17.6
14.977
21.6
19.187
25.6
24.406
29.6
30.833
17.7
15.072
21.7
19.305
25.7
24.552
29.7
31.011
17.8
15.167
21.8
19.423
25.8
24.697
29.8
31.190
17.9
15.262
21.9
19.541
25.9
24.842
29.9
31.369
OF THE VAPOUR OF WATER.
267
c.
Tension.
C.
Tension.
C.
Tension.
C.
Tension.
-j-30.0
31.148
-j-32.0
35J359
-f-33.0
37.410
-f-34.0
mm
39.565
30.1
31.729
32.1
35.559
33.1
37.621
34.1
39.786
30.2
31.911
32.2
35.760
33.2
37.832
34.2
40.007
30.3
32.094
32.3
35.962
33.3
38.045
34.3
40.230
30.4
32.278
32.4
36.165
33.4
38.258
33.4
40.455
30.5
32. 4G3
32.5
36.370
33.5
38.473
34.5
40.680
30.6
32.650
32.6
36.576
33.6
38.689
34.6
40.907
30.7
32.837
32.7
36.783
33.7
38.906
34.7
41.135
30.8
33.026
32.8
3G.991
33.8
39.124
34.8
41.364
30.9
33.215
32.9
37.200
33.9
39.344
34.9
41.595
35.0
41.827
31.0
33.405
31.1
33.596
31.2
33.787
31.3
33.980
31.4
34.174
31.5
34.368
31.6
34.564
31.7
34.761.
31.8
34.959
31.9
35.159
268 TABLE FOR THE CALCULATION
II.
Table for the calculation of the value of 1 + 0.00366 t.
t.
Num.
Log.
t.
Num.
Log.
2.0
0.99268
9.99681
-(-2.0
1.00732
0.00317
1.9
0.99305
9.99697
2.1
1.00769
0.00333
L.8
0.99341
9.99713
2.2
1.00805
0.00349
1.7
0.99378
9.99729
2.3
1.00842
0.00365
1.6
0.99414
9.99745
2.4
1.00878
0.00381
1.5
0.99451
9.99761
2.5
1.00915
0.00397
1.4
0.99488
9.99777
2.6
1.00952
0.00412
1.3
9.99524
9.99793
2.7
1.00988
0.00428
1.2
0.99561
9.99809
2.8
1.01025
0.00444
1.1
0.99597
9.99825
2.9
1.01061
0.00459
1.0
0.99634
9.99841
3.0
1.01098
0.00474
0.9
0.99671
9.99857
3.1
1.01135
0.00490
0.8
0.99707
9.99873
3.2
1.01171
0.00506
0.7
0.99744
9.99888
3.3
1.01208
0.00521
0.6
0.99780
9.99904
3.4
1.01244
0.00537
0.5
0.99817
9.99920
3.5
1.01281
0.00553
0.4
0.99854
9.99937
3.6
1.01318
0.00568
0.3
0.99890
9.99952
3.7
1.01354
0.00584
0.2
0.99927
9.99968
3.8
1.01391
0.00600
0.1
0.99968
9.99984
3.9
1.01427
0.00615
0.0
1.00000
0.00000
4.0
1.01464
0.00631
+ 0.1
1.00037
0.00016
4.1
1.01501
0.00647
0.2
1.00073
0.00032
4.2
1.01537
0.00663
0.3
1.00110
0.00048
4.3
1.01574
0.00678
0.4
1.00146
0.00063
4.4
1.01610
0.00694
0.5
1.00183
0.00079
4.5
1.01647
0.00710
0.6
1.00220
0.00095
4.6
1.01684
0.00725
0.7
1.00256
0.00111
4.7
1.01720
0.00741
0.8
1.00293
0.00127
4.8
1.01757
0.00756
0.9
1.00329
0.00143
4.9
1.01793
0.00772
1.0
1.00366
0.00159
5.0
1.01830
0.00788
1.1
1.00403
0.00175
5.1
1.01867
0.00803
.2
1.00439
0.00191
5.2
1.01903
0.00819
1.3
1.00476
0.00207
5.3
1.01940
0.00834
.4
1.00512
0.00222
5.4
1.01976
0.00850
1.5
1.00549
0.00238
5.5
1.02013
0.00865
1.6
1.00586
0.00254
5.6
1.02050
0.00881
1.7
1.00622 >
0.00270
5.7
1.02086
0.00896
1.8
1.00659
0.00285
5.8
1.02123
0.00912
1.9
1.00695
0.00301
5.9
1.02159
0.00927
OF 1 -f 0.0036G L
2G9
L
i
Num.
Log.
/.
Num.
Log.
-j-G.O
1.02196
0.00943
-}- 10.0
1.03660
0.01561
6.1
1.02233
0.00959
10.1
1.03697
0.01577
6.2
1.02269
0.00975
10.2
1.03733
0.01592
6.3
1.02306
0.00991
10.3
1.03770
0.01607
6.4
1.02342
0.01006
10.4
1.03806
0.01623
6.5
1.02379
0.01022
10.5
1.03843
0.01639
6.6
1.02416
0.01038
10.6
1.03880
0.01653
6.7
1.02452
0.01054
10.7
1.03916
0.016G9
6.8
1.02489
0.01069
10.8
1.03953
0.01683
6.9
1.02525
0.01084
10.9
1.03989
0.01698
7.0
1.02562
0.01099
11.0
.04026
0.01714
7.1
1.02599
0.01115
11.1
.04063
0.01729
7.2
1.02635
0.01131
11.2
.04099
0.01744
7.3
1.02672
0.01147
11.3
.04136
0.01759
7.4
1.02708
0.01162
11.4
.04172
0.01775
7.5
1.02745
0.01177
11.5
.04209
0.01790
7.6
1.02782
0.01193
11.6
.04246
0.01805
7.7
1.02818
0.01208
11.7
.04282
0.01820
7.8
1.02855
0.01223
11.8
.04319
0.01836
7.9
1.02891
0.01238
11.9
.04355
0.01851
8.0
1.02928
0.01253
12.0
.04392
0.01867
8.1
1.02965
0.01269
12.1
.04429
0.01882
8.2
1.03001
0.01284
12.2
.04465
0.01897
8.3
1.03038
0.01300
12.3
.04502
0.01912
8.4
1.03074
0.01315
12.4
.04538
0.01928
8.5
1.03111
0.01330
12.5
.04575
0.01943
8.6
1.03148
0.01346
12.6
.04612
0.01958
8.7
1.03184
0.01361
12.7
.04648
0.01973
8.8
1.03221
0.01377
12.8
.04685
0.01989
8.9
1.03257
0.01392
12.9
.04721
0.02004
9.0
1.03294
0.01407
13.0
1.04758
0.02019
9.1
1.03331
0.01423
13.1
1.04795
0.02034
9.2
1.03367
0.01438
13.2
1.04831
0.02049
9.3
1.03404
0.01454
13.3
1.04868
0.02064
9.4
1.03440
0.01469
13.4
1.04904
0.02079
9.5
1.03477
0.01484
13.5
1.04941
0.02095
9.6
1.03514
0.01500
13.6
1.04978
0.02110
9.7
1.03550
0.01515
13.7
1.05014
0.02125
9.8
1.03587
0.01530
13.8
1.05051
0.02140
9.9
1.03G23
0.01545
13.9
1.05087
0.02155
270
TABLE FOR THE CALCULATION
t.
Num.
Log.
t.
Num.
Log.
-|-14.0
1.05124
0.02170
+ 18.0
1.06588
0.02771
14.1
1.05161
0.02185
18.1
1.06625
0.02786
14.2
1.05197
0.02200
18.2
1.00661
0.02801
14.3
1.05234
0.02215
18.3
1.06698
0.02816
14.4
1.05270
0.02230
18.4
1.06734
0.02831
14.5
1.05307
0.02246
18.5
1.06771
0.02846
14.6
1.05344
0.02261
18.6
1.06808
0.02861
14.7
1.05380
0.02276
18.7
1.06844
0.02876
14.8
1.05417
0.02291
18.8
1.06881
0.02891
14.9
1.05453
0.02306
18.9
1.06917
0.02906
15.0
1.05490
0.02321
19.0
1.06954
0.02921
15.1
1.05527
0.02336
19.1
1.06991'
0.02936
15.2
1.05563
0.02351
19.2
1.07027
0.02951
15.3
1.05600
0.02366
19.3
1.07064
0.02965
15.4
1.05636
0.02381
19.4
1.07100
0.02980
15.5
1.05673
0.02396
19.5
1.07137
0.02995
15.6
1.05710
0.02411
19.6
1.07174
0.03009
15.7
1.05746
0.02426
19.7
1.07210
0.03024
15.8
1.05783
0.02441
19.8
1.07247
0.03039
15.9
1.05819
0.02456
19.9
1.07283
0.03053
16.0
1.05856
0.02471
20.0
1.07320
0.03068
16.1
1.05893
0.02486
20.1
1.07357
0.03083
16.2
1.05929
0.02501
20.2
1.07393
0.03098
16.3
1.05966
0.02516
20.3
1.07430
0.03113
16.4
1.06002
0.02531
20.4
1.07466
0.03128
16.5
1.06039
0.02546
20.5
1.07503
0.03142
16.6
1.06076
0.02561
20.6
1.07540
0.03157
16.7
1.06112
0.02576
20.7
1.07576
0.03172
16.8
1.06149
0.02591
20.8
1.07613
0.03187
16.9
1.06185
0.02606
20.9
1.07649
0.03201
17.0
1.06222
0.02621
21.0
1.07686
0.03216
17.1
1.06259
0.02636
21.1
1.07723
0.03231
17.2
1.06295
0.02651
21.2
1.07759
0.03246
17.3
1.06332
0.02666
21.3
1.07796
0.03261
17.4
1.06368
0.02681
21.4
1.07832
0.03275
17.5
1.06405
0.02696
21.5
1.07869
0.03290
17.6
1.06442
0.02711
21.6
1.07906
0.03305
17.7
1.06478
0.02726
21.7
1.07942
0.03320
17.8
1.06515
0.02741
21.8
1.07979
0.03334
17.9
1.06551
0.02756
21.9
1.08015
0.03349
OF 1 -f 0.003G6 t.
271
t.
Num.
Log.
/.
Num.
Log.
-j- 22.0
1.08052
0.03363
-j-26.0
1.09516
0.03948
2-2.1
1.08089
0.03378
26.1
1.09553
0.03963
22.2
1.08125
0.05393
26.2
1.09589
0.03977
22.3
.08162
0.03408
26.3
1.09626
0.03992
22.4
.08198
0.03422
26.4
1.09662
0.04006
22.5
.08235
0.03437
26.5
1.09699
0.04021
22.6
.08272
0.03452
26.6
1.09736
0.04035
2-J.7
.08308
0.03466
26.7
1.09772
0.04050
22.8
1.08345
0.03481
26.8
1.09809
0.04064
22.9
1.08381
0.03496
26.9
1.09845
0.04079
23.0
1.08418
0.03510
27.0
1.09882
0.04093
23.1
1.08455
0.03525
27.1
1.09919
0.04107
23.2
1.08491
0.03539
27.2
1.09955
0.04122
23.3
1.08528
0.03554
27.3
1.09992
0.04136
23.4
1.08564
0.03568
27.4
1.10028
0.04150
23.5
.1.08601
0.03583
27.5
1.10065
0.04165
23.6
1.08638
0.03598
27.6
1.10102
0.04179
23.7
1.08674
0.03612
27.7
1.10138
0.04193
23.8
1.08711
0.03627
27.8
1.10175
0.04208
23.9
1.08747
0.03642
27.9
1.10211
0.04222
24.0
1.08784
0.03656
28.0
1.10248
0.04237
24.1
1.08821
0.03671
28.1
1.10285
0.04251
24.2
1.08857
0.03685
28.2
1.10321
0.04266
24.3
.08894
0.03700
28.3
1.10358
0.04280
24.4
.08930
0.03714
28.4
1.10394
0.04295
24.5
.08967
0.03729
28.5
1.10431
0.04309
24.6
.09004
0.03744
28.6
1.10468
0.04323
24.7
.09040
0.03758
28.7
1.10504
0.04338
24.8
.09077
0.03772
28.8
1.10541
0.04352
24.9
.09113
0.03787
28.9
1.10577
0.04367
25.0
.09150
0.03802
29.0
1.10614
0.04381
25.1
.09187
0.03817
29.1
1.10651
0.04395
25.2
.09223
0.03831
29.2
1.10G87
0.04410
25.3
.09260
0.03846
29.3
1.10724
0.04424
25.4
.09296
0.03860
29.4
1.10760
0.04438
25.5
.09333
0.03875
29.5
1.10797
0.04453
25.6
.09370
0.03889
29.6
1.10834
0.04467
25.7
.09406
0.03904
29.7
' 1.10870
0.044S2
25.8
1.09443
0.03918
29.8
1.10907
0.04496
25.9
1.09479
0.03933
29.9
1.10943
0.04510
272
TABLE FOR THE CALCULATION
t.
Num.
Log.
t.
Num.
Log.
-j-30.0
1.10980
0.04524
-f- 34.0
1.12444
0.05094
30.1
1.11017
0.04538
34.1
1.12481
0.05108
30.2
1.11053
0.04552
34.2
1.12517
0.05122
30.3
1.11090
0.04567
34.3
1.12554
0.05136
30.4
1.11126
0.04581
34.4
1.12590
0.05150
30.5
1.11163
0.04595
34.5
1.12627
0.05164
30.6
1.11200
0.04610
34.6
1.12664
0.05178
30.7
1.11236
0.04624
34.7
1.12700
0.05193
30.8
1.11273
0.04638
34.8
1.12737
0.05207
30.9
1.11309
0.04653
34.9
1.12773
0.05221
31.0
1.11346
0.04667
35.0
1.12810
0.05235
31.1
1.11383
0.04681
35.1
1.12847
0.05249
31.2
1.11419
0.04695
35.2
1.12883
0.05263
31.3
1.11456
0.04710
35.3
1.12920
0.05277
31.4
1.11492
0.04724
35.4
1.12956
0.05291
31.5
1.11529
0.04738
35.5
1.12993
0.05305
31.6
1.11566
0.04753
35.6
1.13030
0.05319
31.7
1.11602
0.04767
35.7
1.13066
0.05333
31.8
1.11639
0.04781
35.8
1.13103
0.05347
31.9
1.11675
0.04796
35.9
1.13139
0.05361
32.0
1.11712
0.04810
3G.O
1.13176
0.05375
32.1
1.11749
0.04824
36.1
1.13213
0.05389
32.2
1.11785
0.04838
36.2
1 13249
0.05403
32.3
1.11822
0.04852
36.3
1.1328G
0.05417
32.4
1.11858
0.04866
36.4
1.13322
0.05431
32.5
1.11895
0.04881
36.5
1.13359
0.05446
32.6
1.11932
0.04895
36.6
1.13396
0.05460
32.7
1.11968
0.04909
36.7
1.13432
0.05474
32.8
1.12005
0.04923
36.8
1.13469
0.05488
32.9
1.12041
0.04938
36.9
1.13505
0.05502
33.0
1.12078
0.04952
37.0
1.13542
0.05516
33.1
1.12115
0.04966
37.1
1.13579
0.05530
33.2
1.12151
0.04980
37.2
1.13615
0.05544
33.3
1.12188
0.04994
37.3
1.13652
0.05558
33.4
1.12224
0.05008
37.4
1.13688
0.05572
33.5
1.12261
0.05022
37.5
1.13725
0.05585
33.6
1.12298
0.05036
37.6
1.13762
0.05599
33.7
1.12334
0.05050
37.7
1.13798
0.05613
33.8
1.12371
0.05065
37.8
1.13835
0.05627
33.9
1.12407
0.05079
37.9
1.13871
0.05641
OF 1 -f- 0.003GG t.
t.
Num.
Log.
<
Num.
Log.
-j-38.0
1.13908
0.05655
-j-39.0 .
1.14274
0.05795
38.1
1.13945
0.05669
39.1
1.14311
0.05809
38.2
1.13981
0.05683
39.2
1.14347
0.05823
38.3
1.14018
0.05697
39.3
1.14384
0.05837
38.4
1.14054
0.05711
39.4
1.14420
0.05850
38.5
1.14091
0.05725
39.5
1.14457
0.05864
38.6
1.14128
0.05739
39.6
1.14494
0.05878
38.7
1.14164
0.05753
39.7
1.14530
0.05892
38.8
1.14201
0.05767
39.8
1.14567
0.05905
38.9
1.14237
0.05781
39.9
1.14603
0.05919
40.0
1.14640
0.05933
274 TABLE OF THE TENSION OF THE VAPOUR
HI.
Table of the tension of the vapour of absolute alcohol,
according to Regnault. *
.*
Tension
a"
Tension. C.
Tension
c.
Tension.
mm
mm
mm
mm
0.0
12.73
4.0
16.62
8.0
21.31
12.0
27.19
0.1
12.82
4.1
16.73
8.1
21.45
12.1
27.36
0.2
12.91
4.2
16.84
8.2
21.58
12.2
27.53
0.3
13.01
4.3
16.95
8.3
21.72
12.3
27.70
0.4
13.10
4.4
17.05
8.4
21.85
12.4
27.87
0.5
13.19
4.5
17.16
8.5
21.99
12.5
28.04
0.6
13.28
4.6
17.27
8.6
22.12
12.6
28.21
0.7
13.37
4.7
17.38
8.7
22.25
12.7
28.38
0.8
13.46
4.8
17.48
8.8
22.39
12.8
28.55
0.9
13.56
4.9
17.59
8.8
22.52
12.9
28.72
1.0
13.65
5.0
17.70
9.0
22.66
13.0
28.89
1.1
13.74
5.1
17.82
9.1
22.80
13.1
29.07
1.2
13.84
5.2
17.93
9.2
22.94
13.2
29.25
1.3
13.93
5.3
18.04
9.3
23.08
13.3
29.43
1.4
14.03
5.4
18.16
9.4
23.23
13.4
29.61
1.5
14.12
5.5
18.27
9.5
23.37
13.5
29.79
1.6
14.22
5.6
18.38
9.6
23.51
13.6
29.97
1.7
14.31
5.7
18.50
9.7
23.65
13.7
30.15
1.8
14.41
5.8
18.61
9.8
23.79
13.8
30.23
1.9
14.50
5.9
18.73
9.9
23.94
13.9
30.51
2.0
14.60
6.0
18.84
10.0
24.08
14.0
30. G9
2.1
14.70
6.1
18.96
.10.1
24.23
14.1
30.88
2.2
14.79
6.2
19.08
10.2
24.38
14.2
31.07
2.3
14.89
6.3
19.20
10.3
24.53
14.3
31.26
2.4
14.99
6.4
19.32
10.4
24.68
14.4
31.45
2.5
15.09
6.5
19.44
10.5
24.83
14.5
31.64
2.6
15.19
6.6
19.56
10.6
24.99
14.6
31.84
2.7
16.29
6.7
19.68
10.7
25.14
14.7
32.03
2.8
15.39
6.8
19.80
10.8
25.29
14.8
32.22
2.9
15.49
6.9
19.92
10.9
25.44
14.9
32.41
3.0
15.59
7.0
20.04
11.0
25.59
15.0
32.60
3.1
15.69
7.1
20.17
11.1
25.75
15.1
32.80
3.2
15.79
7.2
20.30
11.2
.25.91
15.2
33.01
3.3
15.90
7.3
20.43
11.3
26.07
15.3
33.21
3.4
16.00
7.4
20.55
11.4
26.23
15.4
33.41
3.5
16.10
7.5
20.68
11.5
26.39
15.5
33.61
3.6
16.21
7.6
20.81
11.6
26.55
15.6
33.82
3.7
16.31
7.7
20.93
11.7
26.71
15.7
34.02
3.8
16.41
7.8
21.06
11.8
26.87
15.8
34.22
3.9
16.52
7.9
21.19
11.9
27.03
15.9
34.42
* This table is calculated from recent experiments of Regnault.
OF ABSOLUTE ALCOHOL, ACCORDING TO REGNAULT. 275
y c.
Tension.
C.
Tension.
C.
Tension.
C.
Tension.
16.0
mm
34.62
20.0
mm
44.00
24.0
mm
55.70
28.0
7002
16.1
34.84
20.1
44.27
24.1
56.04
28.1
70.49
16.2
35.05
20.2
44.54
24.2
56.37
28.2
70.89
16.3
35.27
20.3
44.81
24.3
56.70
28.3
71.29
16.4
35.48
20.4
45.08
24.4
57.03
28.4
71.69
16.5
35.70
20.5
45.35
24.5
57.37
28.5
72.09
16.6
35.91
20.6
45.61
24.6
57.70
28.6
72.49
16.7
36.13
20.7
45.88
24.7
58.03
28.7
72.89
16.8
36.34
20.8
46.15
24.8
58.36
28.8
73.29
16.9
36.56
20.9
46.42
24.9
58.70
28.9
73.69
17.0
36.77
21.0
46.69
25.0
59.03
29.0
74.09
17.1
37.00
21.1
46.98
25.1
59.38
29.1
74.53
17.2
37.23
21.2
47.26
25.2
59.73
29.2
74.96
17.3
37.45
21.3
47.55
25.3
60.08
29.3
75.39
17.4
37.68
21.4
47.83
25.4
60.43
29.4
75.82
17.5
37.91
21.5
48.12
25.5
60.78
29.5
76.25
17.6
38.14
21.6
48.40
25.6
61.13
29.6
76.68
17.7
38.36
21.7
48.69
25.7
61.48
29.7
77.12
17.8
38.59
21.8
48.97
25.8
61.83
29.8
77.55
17.9
38.82
21.9
49.26
25.9
62.18
29.9
77.98
30.0
78.41
18.0
39.05
22.0
49.54
26.0
62.53
18.1
39.29
22.1
49.84
26.1
62.90
18.2
39.53
22.2
50.14
26.2
63.27
18.3
39.77
22.3
50.44
26.3
63.64
18.4
40.01
22.4
50.74
26.4
64.01
18.5
40.25
22.5
51.04
26.5
64.37
18.6
40.49
22.6
51.34
26.6
64.74
18.7
40.73
22.7
51.64
26.7
65.11
18.8
40.97
22.8
51.94
26.8
65.48
18.9
41.21
22.9
52.24
26.9
65.85
19.0
41.45
23.0
52.54
27.0
66.22
19.1
41.71
23.1
52.86
27.1
66.60
19.2
41.96
23.2
53.17
27.2
66.99
19.3
42.22
23.3
53.49
27.3
67.38
19.4
42.47
23.4
53.81
27.4
67.77
19.5
42.73
23.5
54.12
27.5
68.15
19.6
42.98
23.6
54.44
27.6
68.54
19.7
43.24
23.7
54.75
27.7
68.93
19.8
43.49
23.8
55.07
27.8
69.31
19.9
43.75
23.9
55.38
27.9
69.70
In the text (p. 143 & c.) the older determinations of Muncke
have been employed.
18*
276
TABLE FOR THE REDUCTION
O
o
O
O
43
tJD
1
<D
P^
iO THCOGMt^COGO'^05 iO r-ICOC^l^COCO^OS iO i * CO OJ t^ CO GO
OOOOOOOOOO o^-it-lr-HT^i-lr^^T-lT^ T-H'-lScNCN
dodddddodd oododooodo d d d d d
OOOOOOOOOO OOOOOOOOOO 050505C5GO
OOOO^OOOOOO c J. 1 - | '- <1 ~i 1 ~3 T ~i 1 ~i'~i r ^ T-J T-I ,H T-H ,-<
dodddddo'dd dooooooodd doddd
OOOOOOOOOO OOOOrHT-ii-lT-lr-jT-H ,_i,_i^2
ddddddodoo oddddddddd ddddc
050505050505050505CO COCOCOCOCOCOCOCOt-t> t>t>t^St^
OOOOOOOOOO OOOOOO > i-lr-li-J^H 2222^^
dodddddodd dodddddddd ddddc
OOOOO>OOOOO OOOOOOOOOrH rH^^^r-
dddddddodd oddddddddd ddddc
oooooooooo oooooooooo o o o TH r-
odoodooodd ddddddodoo ddddd
OOOOOOOOO f O OOOOOOOOOC5 OOOOC
ddddddodoo ddddddddo'd ddddc
iOt-icocNco^tiO5Oi ico <N oo eo 05 "3 o <.> i i t- co c5"*oeoTH
OOOi li IT IT (GMG^GN C^COCOCOCO^t 1 "^'^^ iO lO 1 C iO r ^ O
OOOOOOOOOO OOOOOOOOOO O O O O O
doddoododd dddddddodd odddo
l> ^t* T I CO iO (7^1 O5 O CO ' ( GO vO C?^ O5 CO CO O CO xO ^1 O5 CO CO O t^
OOOOOOOOOO OOOOOOOOOO O O O O O
dddddddodd oddddddddd o'ddoo
OOOOOOOOOO Oi-t^(Hr-lvHi-lT-li-(iH ^H ^1 rH (N <M
oooooooooo oooooooooo c ?; o . c . c ;
dddddddddd dodddddddd ddodo
OF BAROMETRIC OBSERVATIONS TO 0C, 277
r - ~4i~cocc^c5iooc><N i^eooo cs o o o 1-1 i cooo^Ci>ootD--it^co
-N c: :r. x to xocosNGGsr^tcvococ^ o n i -,o T so GN o as i-- o--*ico*HOCit>.cD-+ico
s>j cc co TT o ot>-xa5Cso-H<raco-*i o O to >> ab o O -<<* co-*T>ocoi>.i>.cooiO' <
c* ff> SN s^ ff* (NCXc>jGM(NcococQcQco eocococoeocoTj<TtiT}<Tti -*t & & & -4* ^ -^ Jm ^ \o
d d c d odddddo'ddd dddddddddd dddodddddd
f. f. f- "f. 'f- OO GO QO CO QO 00 CO CO CO GO CO CO CO X O l^. t^. l>. I- l>. t- l^ !> t- t> I> l> t^ t^ l
1-1 00 O 7-1 O> CCCOO1 -fii IXOCMCJ COCOOl^rti-HCOOGMOS O OS O t TJH I GO HO CM Ci
O l> x-O ST. O XCO-r CS[>--* I SNOI-- O C~ X O <# -^ Ci l>- ^ GMOCOOCOT-HCCCD-'tfi-H
o o TI co cc -r i^ vr i~ x> cs o o i i CNT coeo-^iooot^-co OSOO-HCNCOCO-^IIOO
2g M Tl 7-1 > T-l^IJMCNCMS^GMGMCOCO COCOCCCOeOCOCOeOeOCO eO-^->Tl-^i-<*i-^JiTji-^i'^i-<ji
ddddd ddddoddodd dddddddddd dddddddddd
& C-. -T X -N O liOO-*C5COCOfNO O 10 O5 rhi CO CO l^ 7-1 "^CSCOCOCMt^i-HeDOT^
C- L^ ^ CO T * O X !> xO CO7^OC^I>- O ""S^ C^ *" * C5 CO CC xO CO CM O X t>- xO -^ 7^ ~^ CTS CO CD
l.^T-IX)iO IMCiiOtMOOeOOcrcO Ol-^-*-Ht-.-<!tl-HOOOCN OiOfMCSOCOOtOCOO
t-cociCio -Ht-i5<icoeo^foo<iOt>. coccosoo' ICMCMCO-* -^ooot^cocscsOT-i
^r-i^i^-iGM CMGM'M'M7I'M7-1(M7-13M GNJCNC^COCOCOCOCOeOCO COCOCOCOCOCOcOCO^-^i
c c d d o* dddddddddd dddddddddd ddddddddod
r. i-->o
iC tt I - I - XOiOSOOi Iff^C^ICOCO -^OiOOtOI^.XXC5CS Ot ir-lfN5MCO'*i->*l>OO
(pt^i^^^^^-i T-I^-HT-IJNCMCNCNJCNOIT-I CMCMCMCMCMS^CNJGNCNJS^ eocococococococococo
ddddd dddddddddd dddddddddd dddddddddd
r* :t -r 1 o otocDt^t^aoaoooo i i^^cM-McocoTf-^uoio c^coi>-i->.xaociO5OO
ddddd dddddddddd dddddddddd dddddddddd
IMC. t^O-M ^ X ?T SO ' n t^ -*< !M O CO^5-*-lCSI>iO<MOt> lOCO^OOtC^i-ICSIr^O
occi-i^t^csGNioac^ co to 7-1 T i* = c ao i^t^OTT-iidcoococo
T-l^-^iOCiCOXT-l^-H tOACOCOC4OrH)OaCQ CO(MOOiOC5COCO(MtO
ddddd ddd ddd
XCT. ~. riO OO-^^^i-<!MSMCOCOCO ^^^IxOiCiOO^tDlr-. t-.tCOCOOOC5C5OOO
ddddd dddddddddd dddddddddd dddddddddd
tT C". \Z O 7-1 rJH t>- Cl 7-1 rr t-- O 7<I xO t^. O 7-1 lO X O CO iO X O CO ~~2 CO TH CO O CO i-4 CO
CC I >. I>- l>- t*- CO X CO COCTiCTiOOO O O '^ *^ '^ f T ' 7-1 7-1 7-1 *M COCOCOCO^^^^iO i3
o o o o o OOOOOOOO-H^ 1 ~ ( '^'~ ll ~l r ^ T ^'~i'~l T ~i'~i T ^'~i'~i 1 ^ T ^'~J T ^'~i'~J'~ l
ddddd dddddddddd dddddddddd d d d d'd d d d d d
C50000 OOOOOOOOOO OO.OOC5OOOOO 00000 00. i-H T-
- ifl O ^ it^T-lCC^CSKOO-OCN t^cOCO-^050O?r>T-l|- 7<IX^cT5tOOOr-lt^CO
T-i - r-. x to va so 7-1 o c: i- -^ .~ so <N oot^o^eocMOCit^ OTfico^oost^co^co
71 '.~ '.~ i~ L- X ~. ~. ~ 71 CO -^ "3 O iT t^- CO CS O t-< 1-1 <N CO Tji lO to t> t CO OS O -H
ff-1 7-1 71 7-1 7-1 71 71 7-1 71 7-1 CO CO CO CO CO CO CO CO CO CO SO T* * * -* 1 -* T 1 * ^ ^f "=f ^ ^ ^O vO
OOOC:~ OOOOOOOOOO OOOOOOOOOO OOOOOOOOOO
do' odd dddddddddd dddddddddd dddddddddd
278
TABLE FOR THE REDUCTION
dodddddddd ddddddddoo dodo" odd o' o' c
OtO(MOaOiOCOT-lcO O -<*l <7<l C5 t- O GM O OO O CO * C5 CO
dddddddddd o do doddddd oddd
t>
dddodddddd dddddddddd ddddddddo'c
CO GNJ GM GMGMC^^IC^G^l' * T^THI I^HT-HT (r^^-HOO OOOOOOCiQSC
dddodddddd dddodddddd oddddddddc
CO CO CO GO CO COCOCi'^CS ^C^TfC^'^O xO O lO O O OCOiiCOrHcOrHCC^
cocococococoeoeococo coeocoeococoeoTtiTttTt< ^^^TH-*'^(^I^I^<^
dddodddddd dddodddddd dddodddddd
eocococococoeococoeo cocoeoeoeococococort
dddodddddd ddddddoddd dddodddddd
TflCOO'i ICOOCCOCN^t 1 COCOT-HCOiOCOOGM'^'CD COOCOiCb-OCN^COOC
C^GMGMCNGMGNIGMCNGMtT^ CMGMGMCNG^GNIGNIOIC^G'^ GM^lC^JCMGMiTslC^COCCW
dddodddddd ddodddddo'o' ddddddddo'c
lOiOCOCOCOCOI^-Ol t- COCOCOCOO5CSO5OOO O-^-^'-H'-l
T-HrHi IT- IT-HT-II-HT li-Hil ^^^-li-Hi ii li li-H(M(J<IO:i O15<l(M!MCM(Nl?4(NCN!^
dddddddodd dddodddddd dddodddddd
71 K
OOOO-<Hi-li-4rHT-( CN<N<N<M(NCOeOCOCOCO eO.-Ti^-^f'*'^^^^
odododdddo dddddddodd odo'do'do'ddo
OOOOOOOOOO OOC5OOOOOOO OOC5
dddodddddd ddddddoddd do* do
xOOOOiOOiOOiOO
O5Dcot>-i>.ooooa3O5O
cocococoeococococo'^ 1
OF BAROMETRIC OBSERVATIONS TO C. 279
xxxacccaacicscjc; c; ~. ~. n ~. ~ ~ ~ o o
dddddddddd oooooo-H*4
lit LO O lO lO lO lO O O lO lO lO lO lO ^ ^J 1 ^ ^ ^ "^ "^* ^ ^ ^ "^ ^ ^ "^ "^ ^
r co c t~ ^r xut^jcs ir?cot^ x.-^j :-:ot^^ ioooc^d
ox'-sit ciso^reNO t^ o cc o x tr c.t . -M ~ L- i- r: x o ec
co <N co <*( ie o o t^aocioo. -i(Mcoec-o OtDt^t^ooosoO^^i
t* t>- L^ i- t- i- t- i^ i>- t^ i^ t>- t>- cc ac ac ac x cc x cc co GC cc cc cc ci ci ri r;
cc'dooooooo docJooooocJo ddddodddoo
ooooo
o ~ r. ~. ~. x x x x x x; cc cc cc t~ t>- t-- t> t> t>- t
~--DSMQO'^'OCi(MX) *J<OO<MCCTt<Oee<MaC -*OO(MCO-^OtCCNX
TTr^OOCCt^aCCCO5Ci O'-^'-HCM<NC<5'^^fOiO St^t>-aCCCCsOO
in xc o ic o 10 c 10 10 >--: -^ -~ - ~ -~ - - - -- --s CD co t> t> t>. i>
dddddddddd dddddddddd dddddddddd
-. Eooooiooio
ri C-: x d ~- -J: . t^ d :: i~-~ x ^- -r rj 5<i 10 ao o cc o as ~-i ^ t^ o co
~. c- r^ GN cc O Tii c; co t> (N<OO-*O>oOt--tOO ^ -. c- t -- -_DO-*Cico
X -. - O - --- ^J<M COCO-^T}H^iOO--r-^:t^ t>l>.QOQCOC5OOO i
. o
icc~. Mioci^trrieotc cicooocooocot-o
"^f "^- iO lO iO CDCCCOt^-t^ t'-CCCOC^CiC^ O O O
cocococococococococo cocoeococoeo-^-^'-r
O <M 3C <M X O X
o tcJNcccooioo
COtSX CC" X-^-^T
<M (7 ?J (N <M (M C S^l (M CO CO CO CO
iO iOiO^**^Ct^ t^-t^t^t^t^COOOOO GO GC GCO^CiOO^OOOO
dddddodddd dddddddddd dddddddddd
oooooooooo oooooooooo oooooooooo
\f2 O iO O O O id O O O iC O \fl O i5 O tO O tft O iC O iO O iO O iO O >ft O
280
TABLE FOR THE REDUCTION
OOOOOOOOr-l
=f co eo co co co co eococo eo co co co co co co
oooo ooooo
05 o oooooooooo ooS2^^2^i u 2
^S>cccoSco2oco! S^ff^Sas?*" 500 '^^ ^ <*> ^ =c eo t-- .^ - c
^^^aOj-ggOicotMos cocoot^coot^^Scc o 2< oo S ^
QOGOaOQOGOOOCOGOCOCO 00050505050505050505 0505050505C50OO-
ooooocdodoo oooooooooo ooooddr^rH'rt
CO CO 1C C 1C 1C >0 1C 1C 1C rH ^ ^ ^ ^ ^ ^H rj, ^, CO CO CO CO CO ...
^COCO^'SiCCD''c : oS! G 2 "*OcOC-lCO-*iOCO(MOO ^OCOG^CO^fiocSJNi
^ l " ^ "^ l ^I L> : "^ ^ l ": ^ !>; t>- !> 00 GO 90 CO 00 CO CO CO CO CO CC CO OD 00 00 CO X
oooooooooo oooooooooo 6 6 6 6 6 6 6 o d q
ococoococoococoai
O<T<ICOiCCOt>.a5O! I (N
i 1 Cl i 1 CO i 1 CO r-l l^ CM I,.
oooooooooo oooooodocdo
ooooo
OTtiCCCOt^i-HCOO^tlCO COt~-^H
C5 'N 1C 00 O CO C
iO lO iC iO --O iO vO iC O O
oooooooooo
oooooooooo
o o i i I-H <N
oooooooooo
*t^O^Ht>T 1 Tfl OO TH Tjt
'-lT-i(M(M(M e o e oeO^Tt*
'^^'^^f^fTtl-rt'Th'^-^
OOOOOOC5OOO
<7<ll>.' iiCO5-*COC<ICOO iCO5COl--i-ICOO^COM
^liCiCiCCOCOCOl>.l^L>. COCOQOO5O5O5OOO
oooooooooo oooodddddo
10 i-l GO UC5 r-l ' t^ TtH O l> TH
iOi icoijqGoecasiooco
OCOiOOOOCOiCOOi ICO
'i 1 > I'-HI !(MiJ<|<M{McOjf5
cocococococoeocococo
oooooooooo
cOcoSTOtc^S 1 " 11 ^ 10 CO'^OiCi-lt-'NX^
cocoeocococoeocococo cocococococococococ;
oooooooooo ooodddddcd
O l> Tfi i iGOiOCOOr-rtl
t 00 O <? >CO 1T3 t> OS ~O <N
OOi IT- 11 li lili-H(M<7<j
04 O4 94 4 (N 94 G4 C4 ,<N G4
oooooooooo
222222^^' ^^2^^21^222 ScaSSS^S^^^
oooooooooo oooooooooo
ooooo ooooo
iCOiCOiCOiCOiCO iCOiCOiCOiCOiCO
2- fi E5 S C S- 2 Sf.S'?9 iccocoi^i^coaoososo
2
t
OF BAROMETRIC OBSERVATIONS TO 0C. 281
O ~" t^- ?N X CO Ci ^ O tO ~^ CC G^l t** CO 00 ^ Ci *5 OCOi-^t^- ^QOCOCyS^O
~. ~~ N:~ I^-.T-.C i^ x n o ^i -M co ^r o co t oo CO O> O ^^ e* CO 00
e oo eo eo oo co eo oo eo cc " -t c- T-I Tr * ^ ^ -^ ^ -* ^r -<j< t- * 10 o o 10 o
^r 1-1 o5t>o^ooooco-HaD o^s^ot-O'MOccKO
C4CQ co-*ioot^t>aoc50O -HtNCOco^iioot^t^cc
i i ^ <M CM c^ s<i c^ <N<MC^(N<N<NN<Mcoco cococoeococococococo
OOOOOOOOOO
Cl C~. ~. ~. ~. C". ~. C: O O O OOOOOOOOOO
i^. x x cr. ~. o c: i H !M c^eceo-^'-n'ioio^- t>- t^ocxcicnooi I-^<N
o- i- t^- [> i- x x x x co ac oo oc x x x x x oc oo ac ex cc ao GO ci ci ci-o o
eooooooooo oooooooodd dododddood
i~ C -7 X t- t> -^ O O * GCfMt^.-^iCO'^'X^It^ -^iOO-^QOC^r--lir5CS
~ut-jrcst-t-coao ccc5Ooo^H-i-HC^(N eceo^rTfTrioioooo
-_r :r - -,; v; -^: -^ r O cs ^ ^ i>. t> t>- t^ i> r>- t>- i> t>- t> i> t>- t>- t> t>- t>. t-
dcdodddodd dddddddddo dodddddddd
i^ ir: uo u-; u-: ir: o ^ ut o o u-t ut 10 o 10 o o 10 o o o a o >o o o c: --r ^r
d d d d d d o" d d d dddddododd dodddddddd
t-^ it^r^ot r t- -rr t r t^ctO t^^Ot^^Ot^eoOt^
x^ 71 X "t . i^ O O C^ t^- CO O "^T* " t^CO QO^Oi^' !t-C^OO^CS
tOdiOt<Oe4iO(*O COiOCCOCO^X'-^COO CC **<& Z2 ~. -r--r~ .
X r: ~ ~. r: C O O O I Oi G4 C* C4~CO CO OQ CO-^i^ti-^i-^riOiOiOino
OOOOOOOOOO dodddddddd dodddddddd
u- -= vr -j: - - - t> i^. i^ o t> t^ x oc x x x x n cs o o as o o o o o o
N -M -M -M 7-1 <M_ <N (N <N O] CM <N C^ (>l (M_ <N ^ (?a (N CN C^ C<J C^ C^ ff^ CO CO CO CO CO
D o o o o o* o O o o dodddddddd doddddddod
AO^teie^oo^aQ o t>- ac x c; O < ?i :: ?t
dddddddo dodddddddd
282 REDUCTION OF BAROMETRIC OBSERVATIONS.
^^l^H^HOOOOOO OOOOOOOOOO
HT '~Hi li-^ifT iHT li I i I^HT-HT I i-H rH r IT IT IT <
<MT-^OCOI>O-*COCNH oo5cot>io^co<M^o
OCSCiGCCCGCCCCOGCCC COIt--t>-t^l>-t>.t>.l>l^.
C^C^C^O^OO^CiO^OOS OG^CiC^OOOOOO
OOOOOOOOOO cSoOOT^THT-HrHt-^^'
I>.t>t>-l>-l>.l>-t>.GOGOGO COOOOOOOCOOOOOCOGOCC
o'ooooooooo ooo'oooooocs
oooooo'oooo oooooooooo
^*<oi>"*oi~coooeo ot^coot>cooocoo
iO ^f CD (?<l GO CO C5 tO OO CMt^-COCS^O^C^-Ht^-CO
oooooooooo oooooooooo
cocococococococococo cocococoeocococococo
OOOOOOOOOO OOG5OOOOOOO
00000000*00 oooooooooo
TABLE OF THE SPECIFIC GRAVITIES &c.
V.
Table of the specific gravities and composition by
volume of gases.
283
No.
Name of the gas.
Formula.
Volume of the
constituents in 1 vol-
ume of gas.
Specif,
grav.
1
Atmospheric air
0.2096 O-f 0.7904 N
1.00000
2
/Ethyl ....
C 4 H 5
2 vol. C -f 5 vol. H
2.00477
3
Ammonia . . .
NH 3
%vol.N + iy a vol.H
0.58957
4
Antimony . . .
Sb
17.82796
5
Antiinoniuretted-
hydrogen . .
SbH 3
y 4 vol.Sb+lV 2 vol.H
4.56090
6
Arsenic ....
As
10.36510
7
Arseniuretted - hy-
drogen . .
AsH,
y.vol.As+lV.voLH
2.69518
8
Boron ....
Bo
1.50639
9
Bromine ....
Br
5.41085
10
Carbon ....
C
0.82921
11
Carbonic oxide .
CO
y,voi.c-|-y 2 voi.o
0.96741
12
Carbonic acid
CO,
'/ a vol.C + Ivol.O
1.52021
13
Chlorine . . .
Cl
2.45307
14
Chloride of acetyl
C 4 H 3 C1
lvol.C-|-iy 2 vol.H
-f % vol. Cl
2.15965
15
Chloride of boron
BoCl 3
y 4 vol.Bo-flV 2 vol.Cl
4.05620
16
Chloride of cyanogen
C 2 NC1
y 2 voi.c-|-y 2 voi.N
-p/ 2 vol.Cl
2.12681
17
Chloride of methyl
C 8 H 3 C1
%vol.C-j-iy 2 vol.H
1.74504
18
Cyanogen . . .
C,N
Ivol.C -|- Ivol.N
1.80055
19
20
Ditetryl ....
Elayl
C 8 H 8
C 4 H 4
2vol.C -|- 4vol.H
Ivol.C 4- 2vol.H
1.93550
0.96775
21
Fluorine ....
v ^4 4
Fl
1.32673
22
Fluoride of boron
BoFl 3
1 /4 vol.Bo+l 1 Avol.Fl
2.36669
23
Fluoride of silicon
SiFl 3
V 3 vol.Si-{-2voLFl
3.63469
24
Hydrogen . . .
H
0.06927
284
TABLE OF THE SPECIFIC GRAVITIES &c.
No.
Name of the gas.
Formula.
Volume of the
constituents in 1 vol-
ume of gas.
Specif,
grav.
25
Hydrobromic acid
HBr
y s vol.Br-f y a vol.H
2.7400G
20
Hydrochloric acid
HC1
y a voi.ci + y 8 voLH
1.26117
27
Hydrofluoric acid
HF1
y a voi.Fi + y a voi.H
O.G9800
28
Hydriodic acid .
HI
Va VOl.I -fV 2 vol. H
4.42598
29
Iodine ....
I
8.78269
30
Marsh gas . . .
C 4 H t
y 2 vol. C-f 2vol.H
0.55314
31
Methyl ....
C 2 H 3
1 vol. C -1- 3 vol. H
1.03702
32
Methyl -JEther .
C 2 H a O
1 vol. C + 3 vol. H
+ 1 /, vol.0
1.58982
33
Nitrogen . . .
N
0.97134
34
Nitrous oxide
NO
1 vol. N-fy a vol.0
1.52414
35
Nitric oxide . .
N0 2
1 / 2 vol.N-l- 1 / 2 vol.O
1.03847
3G
Oxygen ....
O
1.10561
37
Phosgene gas
CC10
y 2 vol. c-f y 2 voi.o
H-lvol.Cl
3.42048
38
Phosphorus. . .
Ph
4.28424
39
Phosphuretted-hy-
drogen . . .
PhH 3
1 / 4 vol.Ph+l 1 / 2 vol.H
1.17496
40
Selenium ...
Se
5.43076
41
Seleniuretted - hy-
drogen . . .
SeH
y 2 vol.Se-l-lvol.H
2.78465
42
Silicon ....
Si
2.94369
43
Sulphur ....
s
6.63366
44
Sulphurous acid .
S0 2
y e vol. S -j- 1 vol. O
2.21122
45
Sulphuretted -hy-
drogen . . .
SH
y 6 vol.S + lvol.H
1.17488
4G
Tellurium . . .
Te
8.91674
47
Telluretted-hydro-
gen . . . .
HTe
y 2 vol.Te + lvol.H
4.52764
48
Vapour of water
HO
y a vol.O-|-lvol.H
0.62207
TABLE FOR THE REDUCTION OF THE BAROMETER. 285
Table for the reduction of the pressure of a column
of water to a column of mercury.
Pressure
of water
in Mm.
Pressure
of mercury
in Mm.
Pressure
of water
in Mm.
Pressure
of mercury
in Mm.
Pressure
of water
in Mm.
Pressure
of mercury
in Mm.
1
0.07
41
3.03
81
5.98
2
0.15
42
3.10
82
6.05
3
0.22
43
3.17
83
6.13
4
0.30
44
3.25
84
6.20
5
0.37
45
3.32
85
6.27
6
0.44
46
3.39
86
6.35
7
0.52
47
3.47
87
6.42
8
0.59
48
3.54
88
6.49
9
0.66
49
3.62
89
6.57
10
0.74
50
3.69
90
6.64
11
0.81
51
3.76
91
6.72
12
0.89
52
3.84
92
6.79
13
0.96
53
3.91
93
6.86
14
1.03
54
3.99
94
6.94
15
1.12
55
4.06
95
7.01
16
1.18
56
4.13
96
7.08
17
1.26
57
4.21
97
7.16
18
1.33
58
4.28
98
7.23
19
1.40
59
4.35
99
7.31
20
1.48
60
4.43
100
7.38
21
1.55
61
4.50
200
14.76
22
1.62
62
4.58
300
22.14
23
1.70
63
4.65
400
29.52
24
1.77
64
4.72
500
36.90
25
1.84
65
4.80
600
44.28
26
1.92
66
4.87
700
51.66
27
1.98
67
4.94
800
59.04
28
2.07
68
5.02
900
66.42
29
2.14
69
5.09
1000
73.80
30
2.21
70
5.17
31
2.29
71
5.24
32
2.36
72
5.31
33
2.44
73
5.39
34
2.51
74
5.46
35
2.58
75
5.54
36
2.66
76
5.61
37
2.73
77
5.68
38
2.80
78
5.76
39
2.88
79
5.83
40
2.95
80
5.90
28G
TABLE OF THE COEFFICIENTS OF ABSORPTION
VI. Table of the coefficients of absorption
,
Nitrogen
Hydrogen
Oxygen
in
water.
in
alcohol.
in
water.
in
alcohol.
in
water.
in
alcohol.
0.02035
0.12634
0.01930
0.06925
0.04114
0.28397
1
0.01981
0.12593
0.01930
0.06910
0.04007
0.28397
2
0.01932
0.12553
0.01930
0.06896
0.03907
0.28397
3
0.01884
0.12514
0.01930
0.06881
0.03810
0.28397
4
0.01838
0.12476
0.01930
0.06867
0.03717
0.28397
5
0.01794
6.12440
0..01930
0.06853
0.03628
0.28397
6
0.01752
0.12405
0.01930
0.06839
0.03544
0.28397
7
0.01713
0.12371
0.01930
0.06826
0.03465
0.28397
8
0.01675
0.12338
0.01930
0.06813
0.03389
0.28397
9
0.01640
0.12306
0.01930
0.06799
0.03317
0.28397
10
0.01607
0.12276
0.01930
0.06786
0.03250
0.28397
11
0.01577
0.12247
0.01930
0.06774
0.03189
0.28397
12
0.01549
0.12219
0.01930
0.06761
0.03133
0.28397
13
0.01523
0.12192
0.01930 0.06749
0.03082
0.28397
14
0.01500
0.12166
0.01930 0.06737
0.03034
0.28397
15
0.01478
0.12142
0.01930 0.06725
0.02989
0.28397
16
0.01458
0.12119
0.01930
0.06713
0.02949
0.28397
17
0.01441
0.12097
0.01930
0.06701
0.02914
0.28397
18
0.01426
0.12076
0.01930
0.06690
0.02884
0.28397
19
0.01413
0.12056
0.01930
0.06679
0.02858
0.28397
20
0.01403
0.12038
0.01930
0.06668
0.02838
0.28397
21
0.12021
0.01930
0.06657
22
0.12005
0.01930
0.06646
23
0.11990
0.01930
0.06686
24
0.11976
0.01930
0.06626
OF VARIOUS GASES IN WATER AND ALCOHOL.
287
of various gases in water and alcohol.
Carbonic acid
Carbonic oxide
Nitrous oxide
Nitric oxide
in
alcohol.
in
water.
in
alcohol.
in
water.
in
alcohol.
in
water.
in
alcohol.
1.7967
4.3295
0.03287
0.20443
1.3052
4.1780
0.31606
1.7207
4.2368
0.03207
0.20443
1.2605
4.1088
0.31262
1.6481
4.1466
0.03131
0.20443
1.2172
4.0409
0.30928
1.5787
4.0589
0.03057
0.20443
1.1752
3.9741
0.30604
1.5126
3.9736
0.02987
0.20443
1.1346
3.9085
0.30290
1.4497
3.8908
0.02920
0.20443
1.0954
3.8442
0.29985
1.3901
3.8105
0.02857
0.20443
1.0575
3.7811
0.29690
1.3339
3.7327
0.02796
0.20443
1.0210
3.7192
0.29405
1.-2809
3.6573
0.02739
0.20443
0.9858
3.6585
0.29130
1.2311
3.5844
0.02686
0.20443
0.9520
3.5990
0.28865
1.1847
3.5140
0.02635
0.20443
0.9196
3.5408
0.28609
1.1416
3.4461
0.02588
0.20443
0.8885
3.4838
0.28363
1.1018
3.3807
0.02544
0.20443
0.8588
3.4279
0.281-27
1.0653
3.3178
0.02504
0.20443
0.8304
3.3734
0.27901
1.0321
3.2578
0.02466
0.20443
0.8034
3.3200
0.27685
1.0020
3.1993
0.0243-2
0.20443
0.777s
3.2678
0.17478
0.9753
3.1438
0.02402
0.20443
0.7535
3.2169
0.27281
0.9519
3.0908
0.02374
0.20443
0.7306
3.1672
0.27094
0.9318
3.0402
0.02350
0.20443
0.7090
3.1187
0.26917
0.9150
2.9921
0.02329
0.20443
0.6888
3.0714
0.26750
0.9014
2.9465
0.02312
0.20443
0.6700
3.0253
0.26592
2.9034
0.6525
2.9805
0.26444
2.8628
0.6364
2.9368
0.26306
2.8247
0.6216
2.8944
0.26178
2.7890
0.6082
2.8532
0.26060
TABLE OF THE COEFFICIENTS OF ABSORPTION
c.
Marsh gas
Olefiant gas
^Ethyl
in
water.
Methyl
in
water.
in
water.
in
alcohol.
in
water.
in
alcohol.
0.05449
0.52259
0.2563
3.5950
0.03147
0.0871
1
0.05332
0.51973
0.2473
3.5379
0.03040
0.0838
2
0.05217
0.51691
0.2388
3.4823
0.02947
0.0807
3
0.05104
0.51412
0.2306
3.4280
0.02856
0.0777
4
0.04993
0.51135
0.2227
3.3750
0.02770
0.0748
5
0.04885
0.50861
0.2153
3.3234
0.02689
0.0720
6
0.04778
0.50590
0.2082
3.2732
0.02613
0.0693
7
0.04674
0.50322
0.2018
3.2243
0.02541
0.0668
8
0.04571
0.50057
0.1952
3.1768
0.02474
0.0644
9
0.04470
0.49795
0.1893
3.1307
0.02412
0.0621
10
0.04372
0.49535
0.1837
3.0859
0.02355
0.0599
11
0.04275
0.49278
0.1786
3.0425
0.02303
0.0578
12
0.04180
0.49024
0.1737
3.0005
0.02257
0.0559
13
0.04088
0.48773
0.1693
2.9598
0.02216
0.0541
14
0.03997
0.48525
0.1652
2.9205
0.02179
0.0524
15
0.03909
0.48280
0.1615
2.8825
0.02147
0.0508
16
0.03823
0.48037
0.1583
2.8459
0.02121
0.0493
17
0.03739
0.47798
0.1553
2.8107
0.02100
0.0480
18
0.03657
0.47561
0.1528
2.7768
0.02084
0.0468
19
0.03577
0.47327
0.1506
2.7443
0.02073
0.0457
20
0.03499
0.47096
0.1488
2.7131
0.02065
0.0447
21
0.46867
2.6833
22
0.46642
2.6549
23
0.46419
2.6279
24
0.46199
2.6022
OF VARIOUS GASES IN WATER AND ALCOHOL.
289
ulphuretted-hydrogen
Sulphurous acid
Ammonia
in
water.
Atmospheric
air
in
water.
in
water.
in
alcohol.
in
water.
in
alcohol.
4.3706 17.891
68.861 328.62
1049.6
0.02471
4.2874
17.242
67.003
311.98
1020.8
0.02406
4.2053
16.606
65.169
295.97
993.3
0.02345
'.4.1243
15.983
63.360 , 280.58
907.0
0.02287
4.0442
15.373
61.576
265.81
941.9
0.02237
j 3.9652
14.776
59.816
251.67
917.9
0.02179
3.8872
14.193
5SO&0 238.16
895.0
0.02128
3.8103
13.623
56.369 225.25
873.1
0.0200
3.7345
13.066
54.683
212.98
852.1
0.02034
3.659G
12.523
53.021
201.33
832.0
0.01992
3.5858 11.992
51.383
190.31
812.8
0.01953
3.5132 11.475
49.770
179.91
794.3
0.01916
3.4415
10.971
48.182
170.13
776.6
0.01882
3.3708
10.480
46.618
160.98
759.6
0.01851
3.3012
10.003
45.079
152.45
743.1
0.01822
3.2326
9.539
43.564
144.55
727.2
0.01795
3.1651
9.088
42.073
' 137.27
711.8
0.01771
3.098G
8.650
40.608 130.61
696.9
0.01750
1
3.0331 | 8.227.
39.165
124.58
682.3
0.01732
2.9687
7.814
37.749
119.17
668.0
0.01717
2.9053
7.415
36.216
114.48
654.0
0.01704
- 2.8430
7.030
34.986
110.22
640.2
: 2.7817
6.659
33.910 106.68
626.5
2.7215
6.300
32.847 103.77
613.0
: 2.6623
5.955
31.800
101.47
599.5
19
290 CALCULATION OF THE COMPOSITION OF THE ATMOSPHE1
VII. Table for the calculation of the proportioi
Volume of the atmospheric air.
100.00.
200.00.
300.00.
Volume of nitrogen contained ....
79.04
158.08
237.12
Volume of oxygen contained ....
20.96
41.92
62.88
VIII. ' Table for the calculatio:
Name of the gas. i Formula. 1000 CC.
2000 CC. 3000 CC.
Atmospheric air . . .
Grammes.
1.29366
Grammes.
2.58732
Grammes.
3.8809*
/Ethyl .......
C 4 H 5
2.59349
5.18698
7.78047
NH.
0.76271
1.52542
2.28813
A.ntimonv ...
Sb
23.06332
46.12664
69.18996
Antimoniuretted hydrogen
SbH 3
5.90026
11.80052
17.70078
A VQPYllf*
As
13.40892
: 26.81784
40.2267'>
Arseniuretted hydrogen
AsH 3
3.48665
6.97330
10.45995
Boron *
Bo
1.94876
S 897*9
5.84628
Br
6.99990 13.99980
20.99970
c
1.07272
9 14-644
3.21816
Carbonic oxide . . .
CO
1.25150 2.50300
3.75450
Carbonic acid ....
C0 2
1.96664 3.93328
5.8999:'
Chlorine ...
Cl
3.17344 6.34688
9.52032
Chloride of acetyl . .
C 4 H 4 C1
2.79386 5.58772
8.38158
Chloride of boron . .
BoCl 3
5.24735
10.49470
15.74205
Chloride of cyanogen .
C 2 NC1
2.75137
5.50274
8.25411
Chloride of methyl . .
C 2 H 3 C1
2.25749 4.51498
6.77247
Cyanogen
C 2 N
2.32930 4.65860
G.98790
Ditetryl
C 8 P 8
2.50388 5.00776
7.61164
Elayl
C.H,
1.25194 2.50388
3.7W82
Fluorine
V 4 -*4
Fl
1.71634 3.43268
5.14902
CALCULATION OF THE WEIGHTS OF GASES.
291
>f oxygen and nitrogen contained in the air.
400.00.
500.00.
600.00.
700.00.
800.00.
900.00.
316.16
395.20 474.24
553.28 632.32
711.36
83.84
104.80
125.76
146.72
167.68
188.64
of the weight of gases from their volume.
4000 CC.
5000 CC.
6000 CC.
7000 CC.
8000 CC.
9000 CC.
1 Grammes.
Grammes.
Grammes.
Grammes.
Grammes.
Grammes.
5.17464
6.46830
7.76196
9.05562
10.34928
11.64294
' 10.37396
12.96745
15.56094
18.15443
20.74792
23.34141
3.05084
3.81355
4.57626
5.33897
6.10168
6.86439
92.25328
115.31660
138.37992
1(51.44324
184.50656
207.56992
23.60104
29.50130
35.40156
41.30182
47.20208
53.10234
53.63568
67.04460
80.45352
93.86244
107.27136
120.68028
13.94660
17.43325
20.91990
24.40655
27.89320
31.37985
7.79504
9.74380
11.69256
13.64132
15.59008
17.53884
27.99960
34.99950
41.99940
48.99930
55.99920
62.99910
4.29088
5.36360
6.43632
7.50904
8.58176
9.6544*
5.00600
6.25750
7.50900
8.76050
10.01200
11.26350
7.86656
9.83320
11.79984
13.76648
15.73312
17.69976
12.69376
11.17544
15.86720
13.96930
19.04064
16.76316
22.21408
19.55702
25.38752
22.35088
28.56096
25.14474
20.98940
26.23675
31.48410
36.73145
41.97880
47.22615
11.00548
13.75685
16.50822
19.25959
22.01096
24.76233
9.02996
11.28745
13.54494
15.80243
18.05992
20.31741
9.31720
11.64650
13.97580
16.30510
18.63440
20.96370
10.01552
12.51940
15.02328
17.52716
20.03104
22.53492
5.00776
6.25970
7.51164
8.76356
10.01552
11.26746
6.86536
8.58170
10.29804
12.01438
13.73072
15.44706
292
TABLE FOR THE CALCULATION
Name of the gas.
Formula.
1000 CO.
2000 CO.
3000 CC.
Grammes.
Grammes.
Grammes.
Fluoride of boron . .
BoFla
3.06166
6.12332
9.18498
Fluoride of silicon . .
SiFl 3
4.70206
9.40412
14.10618
Hydrogen
H
0.08961
0.17922
0.26883
Hydrobromic acid . .
HBr
3.54471
7.08942
10.63413
Hydrochloric acid . .
HC1
1.63153
3.26306
4.89459
Hydrofluoric acid . .
HF1
0.90298
1.80596
2.70894
Hydriodic acid . . .
HI
5.72573
11.45146
17.17719
1
11.36180
22.72360
34.08540
Marsh gas ...
C 9 H 4
0.71558
1.43116
2.14674
Methyl ....
2 *- A 4
Co Ho
1.34152
2.68304
4.02456
Methyl aether ....
VI *-^8
C 2 H 3
2.05669
4.11338
6.17007
Nitrogen
N
1.25658
2.51316
3.76974
Nitrous oxide ....
NO
1.97172
3.94344
5.91516
Nitric oxide ....
NO 2
1.34343
2.68686
4.03029
Oxygen
o
1.43028
2.86056
4.29084
Phosgene gas ....
CC1O
4.42494
8.84988
13.27482
Phosphorus
Ph
5.54230
11.08460
16.62690
Phosphuretted hydrogen
PhH 3
1.52000
2.04000
4.56000
Selenium
Sc
7.02556
14.05112
21.07668
Seleuiuretted hydrogen
Sell
3.60239
7.20478
10.80717
Si
3.80814
7.61628
11.42442
Sulphur ....
S
17.16336
34.32672
51.49008
Sulphurous acid . . .
S0 2
2.86056
5.72112
8.58168
Sulphuretted hydrogen
SH
1.51991
3.03982
4.55973
Te
11.53525
23.07050
34.60575
Telluretted hydrogen .
HTe
5.85723
11.71446
17.57169
Vapour of water . . .
HO
0.80475
1.60950
2.41425
OF THE WEIGHTS OF GASES FROM THEIR VOLUMES. 293
4000 CC.
5000 CC. 6000 CC.
7000 CC.
8000 CC.
9000 CC.
Grammes.
Grammes.
Grammes.
Grammes.
Grammes.
Grammes.
1-2.24664
15.30830
18.36996
21.43162
24.49328
27.55494
18.80824
23.51030
28:21236
32.91442
37.61648
42.31854
0.35844
0.44805
0.53766
0.62727
0.71688
0.80649
14.17884
17.72355
21.26826
24.81297
28.35768
31.90239
6.52612
8.15765
9.78918
11.42071
13.05224
14.68377
3.61192
4.51490
5.41788
6.32086
7.22384
8.12682
22.90292
28.62865
34.35438
40.08011
45.80584
51.53157
45.44720
56.80900
68.17080
79.53260
90.89440
102.25620
2.86232
3.57790
4.29348
5.00906
5.72464
6.44022
5.36608
6.70760
8.04912
9.39064
10.73216
12.07368
8.22676
10.28345
12.34014
14.39683
16.45352
18.51021
5.026*2
6.28290
7.53948
8.79606
10.05264
11.30922
7.88688
9.85860
11.83032
13.80204
15.77376
17.74548
5.37372
6.71615
8.06058
9.40301
10.74744
12.09087
5.72112
7.15140
8.58168
10.01196
11.44224
12.87252
I7.6997ti
-2-2.12470
26.54964
30.9745*
35.39952
39.82446
22.16920
-27.71150
33.25380
38.79610
44.33840
49.88070
6.08000
7.60000
I). 12000 10.64000
12.16000
13.68000
28.10224
35.12780
42.15336 49.17892
56.20448
63.23004
14.40956
18.01195
21. 61434: -j."). -21673
28.81912
32.42151
15.23-256
19.04070
22.84884
26.65698
30.46512
34.27326
68.65344
So. 81680
102.98016
120.14352
137.30688
154.47024
11.442-24
14.30280
17.16336
20.02392
22.88448
25.74504
6.07964
7.59955
9.11946
10.63937 12.15928
13.67919
46.14100
67.67625
69.21150 i 80.74675
92.28200
103.81725
23.42*92 29.28615 ! 35.14338 I 41.00061
46.85784
52.71507
3.21 1>UU 4.02375 4.82850
5.63325
6.43800
7.24275
294 COMPARISON OP THERMOMETRIC SCALES.
IX.
Table for the comparison of the centigrade thermometer
with Fahrenheit's scale from + 140 to -f- 20 Fah.
w Fah. = Vo ( w 32 ) C -
w o C. = % ^ -\- 32 Fah.
lo Fah. == 055 C. 01 Fah. = 0055 C.
Fahrenheit.
Centigrade.
Fahrenheit.
Centigrade.
Fahrenheit.
Centigrade.
-f 140
60.00
-j- 99
37.22
-j- 58
14.44
139
59.44
98
36.67
57
13.89
138
58.89
97
36.11
56
13.33
137
58.33
96
35.55
55
12.78
136
57.78
95
35.00
54
12.22
135
57.22
94
34.44
53
11.67
134
56.67
93
33.89
52
11.11
133
56.11
92
33.33
51
10.55
132
55.55
91
32.78
50
10.00
131
55.00
90
32.22
49
9.44
130
54.44
.89
31.67
48
8.89
129
53.89
88
31.11
47
8.33
128
53.33
87
30.55
46
7.78
127
52.78
86
30.00
45
7.22
126
52.22
85
29.44
44
6.67
125
51.67
84
28.89
43
6.11
124
51.11
83
28.33
42
5.55
123
50.55
82
27.78
41
5.00
122
50.00
81
27.22
40
4.44
121
49.44
80
26.67
39
3.89
120
48.89
79
26.11
38
3.33
119
48.33
78
25.55
37
2.78
118
47.78
77
25.00
36
2.22
117
47.22
76
24.44
35
1.67
116
46.67
75
23.89
34
1.11
115
46.11
74
23.33
33
0.55
114
45.55
73
22.78
32
0.00
113
45.00
72
22.22
31
-f- 0.55
112
44.44
71
21.67
30
1.11
111
43.89
70
21.11
29
1.67
110
43.33
69
20.55
28
2.2
109
42.78
68
20.00
27
2.78
108
42.22
67
19.44
26
3.33
107
41.67
66
18.89
25
3.89
106
41.11
65
18.33
24
4.44
105
40.55
64
17.78
23
5.00
104
40.00
63
17.22
22
5.55
103
39.44
62
16.67
21
6.11
102
38.89
61
16.11
20
6.67
101
38.33
60
15.55
100
37.78
59
15.00
REDUCTION OF BAROMETER SCALE.
X.
Table for the reduction of the barometer scale from
millimetres into English inches.
Millimetres
Inches.
Millimetres
Inches.
Millimetres
Inches.
700
27.560
730
28.741
760 29.922
701
27.590
731
28.780
761
29.961
702
27.638
732
28.819
762
30.000
703
27.678
733
28.859
763
30.040
704
27.717
734
28.898
764 30.079
705
27.756
735
28.938
765 30.119
706
27.795
786
28.977
766
30.158
707
27.835
737
29.016
767
30.197
708
27.876
738
29.056
768
30.237
709
27.914
739
29.059
769
30.27G
710
27.953
740
29.134
770
30.315
711
27.992
741
29.174
7/1
30.355
712
28.032
742
29.213
772
30.384
713
28.071
743
29.252
773
30.434
714
28.111
744
29 292
774
30.473
715
28.150
745
29.331
775
30.512
716
28.189
746
29.371
776
30.552
717
28.229
747
29.410
777
30.591
718
28.268
748
29.449
778
30.631
719
28.308
749
29.489
779
30.670
720
28.347
750
29.528
780 j 30.709
721
28.386
751
29.567
781
30.749
722
28.426
752
29.607
782
30.788
723
28.465
753
29.646
783
30.827
724
28.504
754
29.685
784
30.867
725
28.543
755
29.725
785
30.906
726
28.583
756
29.71-4
786
30.945
7-27
28.622
757
29.804
787
30.985
728
28.661
758
29.843
788
31.024
729
28.701
759
29.882
789
31.063
28 inches = 711.187 millimetres.
29 ,, = 736.587
30 = 761.986
31 = 787.386
1 millimetre = 0.03937 inch.
U.I = 0.00394 ,.
0.01 = 0.00039
1 inch = 25.39954 millimetres.
0.1 = 2.53995
0.01 = 0.25400
0.001 = 0.02540
29G
REDUCTION OF FRENCH MEASURES
XL Table for converting French decimal measures
1
2
3
Metre.
English yards
1 093f>3
1. M
2 18727
e a s u r e s
3 28090
feet
3 28090
6 56180
9 84270
inches
39 37080
78.74158
118 IPoG
Decimetre.
Feet
32809
65618
98427
Inches
3.93708
7 87416
11 81124
Centimetre.
Inches
39371
78742
1 18U2
Millimetre.
Inches ....
0.03937
0.07874
11811
Litre.
English cuoic inch
61.02711
2. M
122 05429
e a s u r e s
183 08133
.. cubic foot
0.035317
0.070633
0.105950
imp. gallons
quarts
Dints
0.22.017
0.8806(5
1 7G133
0.44033
1.76133
2 52266
0.66050
2.64199
5 28399
Cubic centimetre.
0.06103
12205
18308
Kilogramme.
Cwt ...
01970
03939
3.
0.05909
Ib. (avoir- du-poids)
2.20486
4 40971
6.61457
Kilogramme.
Ib. (troy)
2.67951
5 35903
8 03854
Gramme.
Grains .
15.44242
30 88484
46 32726
Decigramme.
Grains ...
1.54424
3 08848
4.63273
Centigr am me.
Grains .
0.15442
30885
46327
Milligramme.
Grains
0.01544
0.03089
0.04633
AND WEIGHTS INTO ENGLISH MEASURES AND WEIGHTS. 297
nd weights into English measures and weights.
4
5
6
7
8
9
of 1 e n g 1
h.
4.37453
13.12360
157.48315
5.46816
16.40450
196.85394
6.56180
19.68539
236.22473
7.65543
22.96629
275.59552
8.74906
20.24719
314.96630
9.84270
29.52809
354.33709
1.31236
15.74832
1.64045
19.68539
1.96854
23.62247
2.29663
27.55955
2.62472
31.49663
2.95281
35.43371
1.57483
1.96854
2.36225
2.75596
3.14966
3.54337
0.15748
0.19685
0.23623
0.27560
0.31497
0.35434
o i' c a p a
ei t y.
244.10844
0.141266
0.88066
3.52266
7.04531
305.13555
0.176583
1.10083
4.40332
8.80664
366.16266
0.211900
1.32100
5.28398
10.56797
427.18977
0.247216
1.54116
6.16465
12.32930
488.21688
0.282532
1.76133
7.04531
14.09062
549.24399
0.317849
1.98149
7.92598
15.85195
0.24411
0.30514
0.36616
0.42719
0.48822
0.54924
Weigh
t s.
0.07879
8.81943
0.09848
11.02428
0.11818
13.22914
0.13788
15.43400
0.15758
17.63886
0.17727
19.84371
10.71805
13.39757
16.07708
18.75659
21.43610
24.11562
61.76968
77. -2 12 10
92.65352
108.09694
123'.53936
138.98178
6.17697
7.72121
9.26535
10.80969
12.35394
13.89818
0.61770
0.77212
0.92654
1.08097
1.23539
1.38982
0.06177
0.07721
0.09265
0.10810
0.12354
0.13898
19*
298 REDUCTION OF FRENCH TO ENGLISH WEIGHTS.
The mode of using this table is exactly the same as for table
VIII as explained on page 238. An example may serve as illu-
stration.
Let it be required to find how many grains are equal to 87.435
grammes.
By column 8 line 4 of Nr. 3
we have 80
By column 7 line 4 of Nr. 3
we have 7
grammes = 1235.3936 grains.
108.0969
By column 4 line 5 of Nr. 3
we have 0.4
By column 3 line 6 of Nr. 3
we have 0.03
By column 5 line 7 of Nr. 3
we have . 0.005
= 6.1770
= 0.4633
0.0772
87.435 grammes = 1350.2080 grains.
One English foot = 0.30476 metre log. 0.30476 1.4839580.
One English inch m 25.3996 millimetres tog. 25.3996 = 1.4048269.
One English cubic -foot == 28.31 litres tog. 28.31 = 1.451940.
One English cubic- inch = 16.381 cbc. tog. 16.381 = 1.214340.
One English Imp. gallon =P 4.542 litres tog. 4.542 = 0.657247.
One English avoir -du-poids Ib.
= 453.598 grammes tog. 453.598 = 2.656673.
One English troy Ib. = 373.246 grammes tog. 373.246 2.571999.
ERRATA.
Page 70 line 12 i'rom bottom for subtract read add.
70
11
11
M
11
from
to.
70
,. 8
11
11
11
subtracting
read
adding.
70
7
n
11
11
from
11
to.
102
i, *
11
top
11
0.0002
11
0.0021.
102
11 5
11
11
11
17.2712
11
17.2731.
112
4
11
11
11
2.089 B
11
2.090 B.
133
i, 14
11
11
i
water
11
liquid.
134
and 135 for
v l read
K,
throughout.
145
line 8
from
top for
0.0003 read 0.0004.
1 *\f
Q
V
?PNV l
ff\nf\
r pPN V l
100
157
5
11
bottom
for
V l read F .
rCdvl
0.76(^0)
159
12
11
top
11
3.8861 1 3.8944
read 2.8861(2.8944.
167
10
bottom
11
S l read ^.
167
1m Q
6
11
11
11
"2 11 '^2'
y
10
183
,1 2
11
11
top
11
11
11
absorbed read unabsorbed.
193
5
11
11
11
V and Vi read
^ 1 y
X
220
11
11
bottom
11
hydrogen read
oxygen.
222
3
11
top
11
(i 4- y)
(1
-y).
A DH tThf*i , r^ == r ===: ==^ _
s a
THE UNIVERSITY OF CALIFORNIA LIBRARY
