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[CHURCHILL'S TECHNOLOGICAL HANDBOOKS.]

SOAPS AND CANDLES.

EDITED BY

JAMES CAMEEON, F.I.C.

ANALYST Ilf THE LABOBATOKY, SOMERSET HOUSE.

LONDON:

J. & A. CHUECHILL,
11 NEW BURLINGTON STREET

1888.

-T

o Zo

P1IEFAGE.

As in the preceding Handbooks of this series, the articles
in COOLEY'S " Cyclopedia " have been added to from
various scattered sources, so as to present, ill as small a
compass as possible, information which, it is hoped, may
be found useful to technological students and others
interested in the industries described. In order to
economize space, it has been assumed that the student
has some previous knowledge of theoretical and practical
chemistry, and details of many analytical processes,
which are described in general treatises on practical
chemistry, have been, for that reason, omitted.

The Editor has pleasure in expressing his thanks to
Mr. LEOPOLD FIELD, Lambeth, and to Messrs. COOK,
East London Soap Works, for much valuable infor-
mation, and to his colleague, Mr. CHAELES CAETEE, for
assistance in revising the proofs.

J. C.

LOXDOX, May 8, 1888.

CONTENTS.

PAKT I.— SOAPS.

CHAP. PAGES

I. DEFINITION, HISTORY, AND PROPERTIES OP SOAP i — 16
II. MATERIALS. — i. FATTY MATTERS: — ANIMAL
FATS — FISH OILS — VEGETABLE OILS — RE-
COVERED GREASE. — ROSIN. — 2. ALKALIES: —
CAUSTIC-SODA LYES— STEAM LYES — CAUSTIC-
POTASH LYES— ALKALINE SILICATES— SODIUM
ALUMINATE. — PRELIMINARY TREATMENT OP
FATTY MATERIALS :— RENDERING— BLEACH-
ING— BONE-BOILING . 17 — 44

III. HYDROMETERS AND LYE TESTING . . . 45—49

IV. SAPONIPICATION ... ™ ... 50—58
V. APPARATUS AND ARRANGEMENT OF THE FACTORY 59 — 80

VI. CLASSIFICATION OP PROCESSES : — GENERAL PRO-
CESS— SAPONIPICATION UNDER PRESSURE —
COLD PROCESS 81—89

VII. HOUSEHOLD, DOMESTIC, OR LAUNDRY SOAPS :
— i. CURD, OR WHITE, SOAP — 2. GENUINE

viii CONTENTS.

CHAP. PAGES

MOTTLED SOAP— 3. CASTILE SOAP — 4. ARTI-
FICIALLY MOTTLED SOAPS— 5. YELLOW, OR
ROSIN, SOAP — 6. MARINE SOAPS — 7. SILI-
CATED SOAPS— 8. SULPHATED SOAPS . . 90— 1 1 6-

VIII. TOILET, OR FANCY, SOAPS : — MATERIALS— APPA-
RATUS— MANIPULATION — FORMULA— FRENCH

SYSTEM 117 — 144

IX. MEDICINAL SOAPS 145 — 155

X. OLEIC-ACID, RED OR BROWN OIL, SOAPS— SOFT

SOAPS — INDUSTRIAL SOAPS .... 156 — 167
XI. VARIOUS SOAPS AND SOAP POWDERS. — PREPARA-
TION OF SOAP IN SMALL QUANTITIES
XII. RECOVERY OF GLYCERIN FROM SPENT LYES
XIII. TESTING SOAPS.— COMPARISON OF SOAPS

PAET II.— CANDLES.

I. DEFINITION. — HismRY

II. MATERIALS : — ANIMAL FATS— VEGETABLE OILS
— WAXES — FATTY ACIDS. — REFINING PAR-
AFFIN. — PREPARATION OF FATTY ACIDS : —
LIME SAPONIFICATION — ACIDIFICATION — DIS-
SOCIATION BY HEAT — AUTOCLAVE PROCESS —
BOCK'S PROCESS. — SEPARATION OF STEARIC
AND OLEIC ACIDS. — WICKS

CONTENTS. ix

CHAP. PAGES

III. MANUFACTURE : — DIPPING— MOULDING — HAND-

FRAMES — MOULDING MACHINES. — NIGHT-
LIGHTS.— WAX CANDLES 256—270

IV. SPECIALITIES : — ORNAMENTAL CANDLES —

COLOURED CANDLES. — QUALITY OF CANDLES . 271 — 274
V. BYE-PRODUCTS : — OLEIC ACID. — GLYCERIN.—

OLEIN.— TESTING GLYCERIN .... 275—288
APPENDIX: — COMPOSITION OP BLACK ASH. —
STRENGTH OP SOLUTIONS OP CAUSTIC POTASH.
—STRENGTH OP SOLUTIONS OP CAUSTIC SODA.
— SODA ASH : COMPARISON OF ENGLISH AND
FRENCH DEGREES. — EXPORTS OP SOAP AND
CANDLES.— IMPORTS OF TALLOW AND STEARIN.
— STATISTICS OP SOAP AND CANDLE FACTORIES

IN THE UNITED STATES 289—294

INDEX 295—306

BIBLIOGEAPHY.

(English.}

MUSPKATT'S " Chemistry applied to the Arts and TJanufactures."

RICHARDSON and WATTS' " Chemical Technology."

SPON'S " Encyclopaedia of the Industrial Arts.''

URE'S " Dictionary of the Arts and Manufactures."

WAGNER'S " Chemical Technology."

WATTS' " Dictionary of Chemistry."

ALLEN'S " Commercial Organic Analysis " (1886).

CARPENTER'S "Treatise on the Manufacture of Soap, Canutes,

Lubricants, and Glycerin " (1885).

CRISTIANI'S "Technical Treatise on Soap and Candles " (1881).
DUSSAUCE'S "General Treatise on the Manufacture of Soap"

(1869).
FIELD'S Cantor Lectures on " Solid and Liquid Illuminating Agents "

(1883).

KURTEN'S " Art of Manufacturing Soap " (1854).
OTT'S " Art of Manufacturing Soap and Candles " (1867).
MORFIT'S "Chemistry applied to the Manufacture of Soap and

Candles" (1847).

MORFIT'S " Treatise on the Manufacture of Soaps " (1871).
WATT'S " Art of Soap-making" (1884).
WRIGHT'S Cantor Lectures on " Toilet Soaps " (1885).
"Analyst."

" Chemist and Druggist."
" Journal of the Chemical Society."
" Journal of the Society of Arts."
"Journal of the Society of Chemical Industry."
" Pharmaceutical Journal."
" Year Book of Pharmacy."

SOAPS AND CANDLES

PART I.-SOAPS.

CHAPTER I.

DEFINITION, HISTORY, AND PROPERTIES
OP SOAP.

Definition. — Chemically speaking, a soap is produced when-
ever a metallic base is combined with & fatty acid, such as
the acids, of the general formula CnH2a_2O2, occurring in,
or obtainable from, the natural fats or fixed oils, and hence,
besides the ordinary commercial soaps, we have the lead soap,
or lead plaster of pharmacy, and also manganese, copper,
mercury, zinc, tin, silver, cduminium, and other metallic
soaps. But, in ordinary language, by soap we understand
a compound of an alkali and a fatty acid — the alkali potash
affording, when so combined, soft soap, and the alkali soda
forming hard soap.

According to another definition, soap is a chemical com-
bination of any oily with any saline matter, whereby the
oil acquires a solubility in menstrua with which, naturally,
it refuses to unite.

MORFIT says : " True soap is a definite chemical compound

2 SOAPS.

of one or more fat acids with a base, and a certain ratio of
water of constitution."

KJNGZETT* gives this definition : " Soap, considered com-
mercially, is a body which, on treatment with water, liberates
alkali."

A similar definition is mentioned in the Reports of the
Juries, Exhibition 1851 (p. 607): "Soap is a sort of
magazine of alkali, which it gives up in the exact quantity
required at any moment when it is rubbed with water."

Dr. C. R. A. WRIGHT f states that "a soap, in the widest
sense of the term, implies a compound of a fatty acid with
an alkali, or other metallic derivative capable of playing
the part of an alkali, glycerides not being classed as soaps,
for the reason that glycerin, although capable to a certain
extent of playing the part of an alkali, is neither such a
metallic derivative nor an alkali itself."

History. — A complete soapery was found in excavating
Pompeii, which contained some soap in a good state of pre-
servation. Hence we are at once thrown back to the year
A.D. 79 in our search for the first employment of soap. The-
elder PLINY, who perished at that time, is the first writer
who mentions soap in the sense in which we now under-
stand the word. He states J that it was made from tallow
arid ashes, the best materials being goat's tallow and beech-
ask. He was also acquainted with the hard and soft varieties
of soap. He ascribes the invention of the compound to the-
Gauls, but states that it was well prepared in Germany..
References to cleansing by writers before this time only
show that soap was unknown to them ; for instance, HOMER
gives us§ an account of the washing expedition of NAUSIKAA,.

* "The Alkali Trade," p. 173.

| Cantor Lectures on Toilet Soaps, May 4, 1885.

J "Nat. Hist." xxviii. 12, 51 (HOLLAND'S translation, ii. 328).

§ "Odyssey," vi. 90-118.

HISTORY OF SOAP. 3

but without any mention of soap. The word occurs twice
in the Scriptures,* but the original word in both instances
is borith, and BECKMANN has shown t that this really means
alkali.

We have distinct evidence that soap-making nourished
in the seventeenth century, but it is only in the most modern
times that the manufacture attained that extraordinary
development for which this industry is remarkable, and
which gave occasion for the following oft-quoted remarks
of LTEBIG : " The quantity of soap consumed by a nation
would be no inaccurate measure whereby to estimate its
wealth and civilization. Of two countries with an equal
amount of population, we may declare, with positive cer-
tainty, that the wealthiest and most highly civilized is that
which consumes the greatest weight of soap." J

Various circumstances have contributed to the advance-
ment of this manufacture since the commencement of the
present century, but two discoveries have specially influenced
it — viz., CHEVREUL'S discovery of the true nature of fats,
and LEBLANC'S discovery of a method for the artificial pre-
paration of soda on a large scale. CHEVREUL'S researches,
although they explain the nature of saponification, have
perhaps contributed less to the progress of the soap manu-
facture than to that of candle-making, but the development
of the manufacture of soda has proved a most powerful
stimulus to that of soap, by freeing it from dependence on
the uncertain and limited supply of barilla and kelp.

Soap was formerly heavily taxed. An excise duty of id.
per Ib. was first imposed in 1711 on all soap made in Great
Britain, and in 1713 this was raised to i±d. per Ib. In

* Jer. ii. 22 ; Mai. iii. 2.

f " History of Inventions," translated by JOHNSON (BOHN).

j " Familiar Letters on Chemistry," letter xi. p. 129.

B 2

4 SOAPS.

1782 the duty was again increased, and a distinction was for
the first time made between hard and soft soaps, the duty
on the former being 2\d. and on the latter ifd. per Ib. In
1816 the duty on hard soap was raised to $d. per Ib. In
1833 the duty was i%d. per Ib. on hard soap and id. per Ib.
on soft. The duty was repealed in 1853.

Properties. — Only soaps made from alkalies and fatty
acids are soluble in water, and consequently such only are
valuable for cleansing purposes, and are commercially recog-
nized as soaps. All other soaps are insoluble in water, the
most familiar of these insoluble soaps being the lime soap,
which separates in curdy particles whenever hard water is
used for ordinary washing purposes.

But cold water, however pure, never entirely dissolves
soap without decomposition. The neutral salts of which soap
consists are resolved, in contact with water, into an alkali
which dissolves and an acid salt which .is precipitated.*
The same decomposition takes place when hot weak solutions
of soap are cooled. This behaviour explains why, in using
soap even with the purest cold water, a white turbidity
(soap-suds) is always produced. On this decomposition,
probably, the purifying action of soap largely depends. The
liberated alkali unites with the greasy dirt, and the insoluble
acid salt forms the lather which envelopes it, and thus assists
its removal.

According to Dr. W. LANT CARPENTER^ considerable light
has been thrown upon the manner of removal of dirt by
soap by the researches of the late Prof. W. STANLEY
JEVONS, F.R.S., upon the " Brownian movement " of small
particles. When clay is stirred up with water, and the

* MUSPRATT'S " Dictionary of Chemistry," ii. 875 ; WATTS' " Dic-
tionary of Chemistry," v. 315 ; Srox's " Encyclopaedia," v. 1793.
f SPON'S "Encyclopaedia," v. 1793.

PROPERTIES OF SOAP. 5

water is allowed to stand, it clears itself very slowly, and
microscopic examination showed that this was due to a kind
of molecular movement of the infinitesimally small particles
of the clay. To this movement Prof. JEVONS gave the name
of pedesis, or pedetic action,* and he found that soap and
sodium silicate enormously increased this action.t From,
these observations, and from his own experiments, CAR-
PENTER is of opinion that in the action of these substances in
promoting the molecular movement of extremely minute
particles is to be sought part of the explanation of the
cleansing power of soap.

Soap is readily soluble in alcohol and in hot water. A
hot concentrated solution of ordinary soap solidifies on cool-
ing to a jelly-like mass. Soap is insoluble in a solution of
common salt, and if the latter is added to a hot solution of
the former, the soap separates as an oily layer, which solidi-
fies on cooling.

Prof. ROTONDI, of the Eoyal Industrial Museum of Turin,
rejects the theory of BERZELIUS that the usefulness of soaps
depends upon the facility with which neutral soaps decom-
pose, on solution, into acid soaps and free alkali, and also
that of PERSOZ, who assumes neutral soaps to be soluble
in hot water without decomposition, but to be resolved in
cold water into acid and basic soaps, the latter dissolving
fatty substances by saponification. These hypotheses do
not explain why hot soap solutions are more active than
cold ones. The following conclusions were arrived at by
ROTONDI from experiments upon carefully purified Mar-
seilles soap: — Neutral soaps are decomposed, on solution,
into basic and acid soaps ; the latter are insoluble in cold,
and only slightly soluble in hot water ; they are not dia-

* " Quarterly Journal of Science," April 1878, No. Iviii.
f Report of the British Association, 1878, p. 435.

6 SOAPS.

lysable, and so are thus separable from the former, which
readily dialyse. The neutral soaps, though thus decom-
posed, lose neither free nor carbonated alkali. Basic soaps
are completely soluble in hot and cold water, and are
entirely precipitated by sodium chloride without loss of
alkali ; their solutions dissolve acid soaps on heating, but
become turbid on cooling. They emulsify fatty bodies
readily, but no saponification of the latter takes place ;
neutral soaps possess this property to a smaller extent ; acid
soaps scarcely at all. Carbonic acid produces, in cold solu-
tions of basic soaps, insoluble compounds, which, however,
disappear on heating. Hence, waters rich in carbonic acid
are not suited for industrial operations with soap. The
above explains the greater efficiency of hot soap solutions,
and has an important bearing upon the manufacture and
industrial uses of soap, inasmuch as different results are
often observed in the use of soaps made from the same
materials (and containing no free alkali), which are due to
their containing variable amounts of acid and basic soaps.
ROTONDI considers that soaps should consist, as nearly as
possible, of neutral compounds, instancing the injury arising
in the boiling of silks from the presence of excess of basic
soap, and that these points should be borne in mind in the
operations of soap-boiling, as well as in soap analysis, when
it is desired to ascertain the fitness of a sample for a given
purpose.*

The partial decomposition of a neutral soap when treated
with cold water is called hydrolysis, and has been recently
carefully investigated by WRIGHT and THOMPSON, f with
very interesting results. Their experiments were made as

* "Chem. Kev." xiv. 228 ; " J. Soc. Chem. Ind." 1885, p. 601.
t " J. Soc. Chem. Ind." 1885, p. 629.

. PROPERTIES OF SOAP. 7

follows: — The soaps examined were either prepared by
themselves, or obtained from manufacturers with infor-
mation as to the fatty acids present ; they were carefully
examined, and, in those cases where minute amounts of free
alkali were present, corrections were made for these small
.amounts. Weighed quantities of soap, representing known
quantities of anhydrous soap, were dissolved in known quanti-
ties of distilled water on the water-bath, and, after cooling
to near the ordinary temperature, the liquids were treated
with pure sodium chloride, so as to throw out of solution all,
or nearly all, the soap as curd. The curds thus precipitated,
on drying and dissolving in alcohol, were always more or
less acid, phenol- phthalein being the indicator, so that one
way of determining the amount of hydrolysis was to
determine the amount of alcoholic potash or soda solution
required to neutralize this acidity. It was found, however,
in practice to be far more convenient to determine the
.alkali contained in an aliquot part of the brine, correcting
the amount found for the free alkali (if any) originally
contained in the soap. With smaller proportions of water,
the addition of moderate quantities of salt sufficed to
throw all soap out of solution so perfectly that, at most,
only traces of fatty acids could be obtained from the brine
by acidulating and shaking with ether ; with larger pro-
portions it was found convenient to evaporate the brine
•until nearly saturated, and filter again from any soap
thrown out of solution during the evaporation, using only
a fraction of the salt requisite to saturate the water for the
salting out, rather than to use more salt in the first instance
and titrate without evaporation, greater accuracy in hitting
the terminal reaction being thus attained. With cocoa-nut
oil soaps the brines were evaporated to dryness, and then
treated with just sufficient water to dissolve the salt, and

SOAPS.

filtered. In this way, liquids free from more than traces of
soap were obtained, the soap originally contained in the-
brine before evaporation being thus eliminated. The
following corrected mean values were obtained in a lengthy
series of experiments with various soda soaps, all of which
were neutral or only faintly alkaline. The numbers represent
the quantities of Na20 set free by hydrolysis, reckoned per
100 parts of Na20 combined with fatty acids in the soap^
x molecules of water being used for one of anhydrous
soap.

Fatty Acids.

Mean
Mole-

Hydrolysis bro

light about by x M
of Water.

olecules

Weight.

^=150. la;— 250.

#=500. , #=1000.

X = 2000.

Pure stearic acid

284

0.7 | 1.0

1.7 1 2.6

3-55

Nearly pure palmitic

acid

2tf

1.45 1.9

2.6 3.15

3-75

Crude lauric acid

(cocoa-nut oil soap)

195

3-75 i 4-5

5-4 6.45

7-1

Pure oleic acid .

282

1.85 2.6

3-8 q.2

6.65

Crude ricinoleic acid

(castor oil soap)

294

1.55 2.2

3-o 3-8

4-5

Chiefly stearic, palmi-

tic and oleic acids

(palm oil and tallow

soap)

271

I.I 1.55

2.6 4.I

5-3

Chiefly tallow and

resin (primrose)

280

1.5 I 2.2

3.1 4.2

5-3

Cotton seed

250

2.25 | 3.0

5-o ; 7-5

9-5

The above results lead to the following general con-
clusions : —

1. The amount of hydrolysis brought about by the
action of a given quantity of water on a neutral soap is
variable with the nature of the fatty acids from which the
soap is made, but in all cases increases with the amount of
water employed relatively to the soap, but less rapidly.

2. Addition of excess of alkali to a neutral soap causes
a diminution in the amount of hydrolysis effected under

PROPERTIES OF SOAP. 9

given conditions, to such an extent as completely to stop
the action with comparatively small proportions of waterr
when the free alkali only amounts to a fraction (say 20-25
per cent.) of the alkali combined with the fatty acids.

3. Alcohol, even when not absolutely anhydrous (90-95
per cent.), does not decompose ordinary neutral soaps intc*
free alkali and acid salts. If, however, water be added to
an alcoholic soap solution, more or less hydrolysis takes
place, so that if a gelatinous mass of neutral soap, dissolved
in strong spirit containing a little phenol-phthalein, be
treated with water, a more or less strongly marked coloration
is noticeable as the water diffuses into the mass.

The following observations of LIEBIG on the behaviour of
soap with a solution of common salt are of great practical
importance to the soap-maker : — " If a piece of common
hard soap be placed in a solution of salt at ordinary tempera-
ture, it floats upon the surface without even being moistened,
and, if the liquid be heated to boiling, it separates without
foam into gelatinous flocculse, which collect on the surface,,
and, upon cooling, unite into a solid mass, from which the
solution flows off like water from fat. If the floccuke be
taken out of the hot fluid, they congeal, on cooling, into an
opaque mass, which may be pressed into fine laminae between
the fingers without adhering to them. If the solution is
not quite saturated, the soap then takes up a certain
quantity of water, and the flocculae separate through the
fluid on boiling. But even when the water contains ^ J^th
part of common salt, ebullition does not produce solution.
If the soap is boiled in a dilute and alkaline solution of salt,
and suffered to cool, it again collects on the surface of the
fluid in a more or less solid state, depending on the greater or
less degree of concentration of the solution — that is, on the
quantity of water taken up by the soap. By boiling the
dilute solution of salt with soap for a considerable time, the

io SOAPS.

aqueous flocculse intumesce, and the mixture assumes a
foam}* appearance ; but still they are not dissolved, as
the solution separates from them. The flocculse, however,
have become soft and pasty, even after cooling, and their
pastiness is due to the quantity of water they have
taken up. By continuing the boiling, this character again
•changes, and in proportion as the water evaporating renders
the solution more concentrated, the latter again extracts
water from the noccuke ; the liquid, however, continues to
foam, but the bubbles are larger. At length a point is
reached at which the solution becomes saturated ; the
larger iridescent bubbles, formed just before, disappear,
and the liquid continues to boil without froth; all the
•soap collects as a translucent mass on the surface ; and now
the solution and soap cease to attract water from each other.
If the plastic soap be now removed and cooled, while the
solution is pressed out, it becomes so solid as scarcely to
receive an impression from the fingers. In this state it is
•called grain-soap.

11 The addition of salt, or its solution, to a concentrated
alkaline solution of soap in water, precipitates the soap in
gelatinous flocculae, and the mixture behaves precisely as
solid soap boiled with a solution of salt. Potassium car-
bonate and caustic potash act exactly as salt in separating
soap from the alkaline fluid.

"The application of these facts to the manufacture of
soap is obvious. The fat is kept boiling in an alkaline lye
until all pasty matters disappear ; but the lye should have
only a certain strength, so that the soap may be fairly
dissolved in it. Thus, tallow may be boiled for days in a
caustic potash solution of specific gravity 1.25 without
being saponified. If the lye be stronger, a partial saponi-
fication ensues ; but, being insoluble in the fluid, the soap
floats on the surface as a solid mass. By the gradual addi-

PROPERTIES OF SOAP. 11

tion of water, with continued boiling, the mass at a certain
point becomes thick and clammy, and with more water an
emulsion is formed. On continued heating, this becomes
perfectly clear and transparent if a sufficient quantity of
alkali be present. In this state it may be drawn out
into long threads, which, 011 cooling, either remain
transparent, or are milky and gelatinous. As long as
the hot mass suffered to drop from a spatula exhibits a
milkiness or opalescence, the boiling is continued, or more
alkali added. When excess of alkali is present, the milki-
ness arises either from imperfect saponification, or want of
water , the former is known by dissolving a little in pure
water, which becomes perfectly clear when the whole is
saponified. If the lye contain lime, the mixture is also
turbid, but the addition of an alkaline carbonate causes the
turbidity arising from this cause to disappear instantly.

" In order to separate the soap from water, free alkali, and
glycerin, a large quantity of salt is gradually added to the
boiling mass, waiting, after each addition, .till the portion
added is completely dissolved. The first addition increases
the consistency of the mass, while each successive portion
renders it more fluid, till it loses its adhesive character, and
drops from the spatula in short thick lumps. As soon as
the congelation is complete — that is, when gelatinous floc-
culse separate from a clear watery liquid — the fire is extin-
guished, the soap allowed to collect on the surface, and
cooled either on the liquid or ladled out, and allowed to get
solid.

" The same results are also produced, although in a less
energetic manner, by potassium chloride, alkaline car-
bonates, sodium sulphate, potassium acetate, and ammo-
nium chloride. Of these, sodium sulphate and potassium
chloride have but a very slight action. Concentrated
caustic lyes also separate soap from its solution in the

12 SOAPS.

same manner as common salt. In weak caustic tye, on the
contrary, soap is perfectly soluble. On this account, soap-
boilers, especially at the commencement of the operation,
except in the case of cocoa-nut oil, always use weak lyes, as
the stronger would prevent the necessary amount of contact
amongst the ingredients, and very much retard the process
of saponification. Thus, by means of caustic or saline solu-
tions, not only all foreign matters, but also the glycerin,
may be completely separated from soap."

T. N". WHITELAW,* starting with the well-known fact that
soaps, when boiled with solutions of common salt, retain
amounts of water inversely as the quantity of sodium chloride
in solution, has described certain experiments instituted by
him with the view of denning this action. Tallow and palm-
nut oil soaps were selected as affording types of the manner
in which solutions of soap behave with salt, the greater
number of oils used in soap-making resembling tallow,
while cocoa-nut oil is more like palm-nut oil in the manner
in which its soap solution behaves. Six grms. of fatty
acids from tallow and palm-nut oils respectively were
saponified in a flask of about 250 c.c., separated with excess
of caustic soda from solution, and, after cooling till the soap
curds had solidified, the caustic soda liquor was allowed to
drain off.

The soaps so obtained were dissolved in 100 c.c. of distilled
water, and a weighed quantity of pure NaCl added, enough to
obtain distinct separation of the soap in small curds. Then
water was added in small quantities from a burette, and
the soap solution brought to the boiling point and well
agitated after each addition, a cork provided with about
14 inches of glass tubing preventing any loss of water
during the momentary boiling.

* " Journ. Soc. Chem. Ind." 1886, p. 90.

PROPERTIES OF SOAP. 13

With a certain strength of solution, the soap grains were
distinct and separate, without any tendency to settle out
fluid soap. With a further addition of water, the grains
became softer, and a thin layer of fluid soap could be ob-
served settling beneath them. With the addition of still
more water, the grains became entirely fluid, and the fluid
soap occupied more and more of the total fluid volume as
more water was added, until a point was reached when the
fluid became clear and bright, and the soap completely dis-
solved.

The points of distinct separation in grains, and the points
of complete solubility in boiling solutions, were found to be
as follow : —

Separation in
Distinct Grains.
NaCl per Cent.

Completely
Soluble.
KaCl per Cent.

Tallow soap ....
Palm-nut oil soap . . ,

6.5
18.0

3-0
13.0

On cooling these solutions, the tallow soap remained com-
pletely soluble, and, when cold, formed a firm jelly, while
the palm-nut oil soap separated as it cooled into a thin
layer on the surface of the salt solution. It was found that
the tallow soap is nearly as soluble in the cold as in the hot
solution of salt, but that while palm-nut oil soap is soluble
in boiling water containing 13 per cent, of NaCl, it is in-
soluble in cold solution of 3 per cent.

A difference was observed in the composition of the soap
according as it separated in distinct grains from the saline
solution, or as slightly liquefied grains floating on a thin
layer of liquid soap above the solution. In the first case
we have an ordinary soft curd soap, and in the second case,
if we consider the subnatant saline solution removed, we
have soap grains washed by a solution of soap. Both these
methods — viz., purifying with salt and purifying with soap

SOAPS.

— are adopted on the large scale to obtain pure soap of a
definite composition.

WHITELAW obtained the following results from the
analysis of the two soaps thus prepared : —

Soap settled from

Salt.

Soap.

Palm Oil— Curd.

Tallow— Fitted Soap.

Water .

Soda(Na,0) .
Fatty anhydrides .
Sodium chloride .

• • 1 3I-38

: : $2

• , 1.67

314

7-0
60.3
i-3

100.00

IOO.O

Action of More Concentrated Solutions of Common Salt
upon Soaps. — A soap from a good quality of olive oil, after
boiling for thirty minutes with an 8 per cent, solution of
salt, retained 31.6 per cent, of water; with a 17 per cent,
solution, it retained 25.7 per cent. ; and with a saturated
salt solution, it retained 19.1 per cent.

The following are analyses of various soaps after thirty
minutes' treatment with a hot saturated solution of salt : —

Soap.

Water.
Per Cent.

Fatty
Anhydrides.
Per Cent.

Soda.
Per Cent.

Sodium
Chloride.
Per Cent.

Olive oil
Tallow .
Palm-nut
Cotton oil
Castor oil

ig.i
16.94
iS.8
17.2

48-3

67.9
64.49
66.4
62.4
31-3

7.8
7.64
9-9
6.4
37

5-2
10.93

4-9
14.0
I6.7

Prolonged boiling does not reduce the quantity of water
retained by the soap after thirty minutes' treatment. This.
is shown by the following analysis of a soap after sixty
minutes' treatment : —

PROPERTIES OF SOAP. 15

Olive Oil Soap — treated Sixty Minutes.

Water

Fatty anhydrides ....

Soda

Sodium chloride ....

100.00

There is thus a limit to the action of sodium chloride in
withdrawing water from soaps.

Soap which contains a larger amount of water than curd
soap is called ivatered when water or weak lye is added and
mixed with the curd in the pan itself, or when the curd is
treated subsequently with water whilst still in contact with
the brine. When, however, the water is added and crutched
into the curd after its removal from the pan, the soap is
termed liquored or filed. The term filed is also applied to
soap which has been mixed either with the soluble alkaline
carbonates, sulphates, or silicates, or with such insoluble
materials as barium sulphate, chalk, clay, china clay, fuller's
earth, pumice stone, sand, steatite, starch, talc, &c.

The following are the characters of soap given in the
British Pharmacopoeia (1885) : —

HARD SOAP (Sapo durus : white Castile soap), made from
soda and olive oil. — Colour, yellowish-white. Dry, inodor-
ous. Horny, and pulverizable, when kept in dry warm air.
Easily moulded when heated. Soluble in rectified spirit.
Soluble also in hot water, the solution being neutral or only
faintly alkaline to test-paper. It does not impart a greasy
stain to paper. Incinerated, it yields an ash which does
not deliquesce.

CURD SOAP (Sapo animalis). — Made from soda, and a
purified animal fat consisting principally of stearin.
Colour, white, or with a very light-greyish tint. Other-
wise, its characters are the same as those of sapo durus.

SOFT SOAP (Sapo mollis). — Made from potash and olive

1 6 SOAPS.

oil. Colour, yellowish-green. Inodorous. Of a gelatinous
consistence. Soluble in rectified spirit. Does not impart
an oily stain to paper. Incinerated, it yields an ash which
is very deliquescent.

The United States Pharmacopoeia (1883) gives the
following characters of soap prepared from soda and olive
oil : — A white or whitish solid ; hard, yet easily cut when
fresh ; having a slight, peculiar odour, free from rancidity ;
a disagreeable, alkaline taste, and an alkaline reaction.
Readily soluble in water and in alcohol. When cut into
thin slices, and dried to a constant weight at a 'temperature
of 110° C. (230° F.), it should not lose more than 34 per
cent, of its weight (absence of an undue amount of water).
A 4 per cent, alcoholic solution should not gelatinize on
cooling (absence of animal fats). 100 parts of the soap
when dissolved in alcohol should not give more than 3 parts
of insoluble residue (limit of sodium carbonate, &c.), and at
least 2 parts of this residue should be soluble in water
(limit of silica, and. other accidental impurities).

CHAPTER II.
MATERIALS.

THE materials which are essential to the soap manufacturer
may be classified under two heads : — i. Fatty matters and
rosin ; 2. Alkalies.

i. FATTY MATTERS.

The fatty substances employed have been fully described
in the fourth volume of this series of Handbooks,* but the
tabular statement given on pp. 18-22 will be convenient
here.

Recovered Grease. — Obtained from the washings of
woollen works. These are decomposed with sulphuric acid,
steam is admitted to hasten separation, the fatty acids are
filtered through hempen cloth, and the fatty mass then
subjected to hydraulic pressure. It is of a brownish colour,
and requires to be used with judgment, as it is liable to con-
tain varying quantities of unsaponifiable oils. Also, extracted
by carbon disulphide from the residue of stearin factories,
from sawdust which has served for filtering oil, from refuse
waggon grease, from oily rags, &c.

Recovered grease is never used alone in soap-making, but
mixed with palm oil or tallow, and chiefly "for rosin soaps.

Rosin. — Syn. COLOPHONY. — This is an important ingre-
dient in the production of soap. It is the residue left

* "Oils and Varnishes."

SOAPS.

•a

£ .

i'sj

a o M

§."=

I III!

^^ ^^ " ^ rri

;il

.««

. . bo

iai!

3 SM fl <»
J n '5 tL

«*i

3 S

-So

W 03

.11

§3

C rrj g t* ««P

MATERIALS.

CJv.tQQ

-^ 03 -

fto I tf

to -2 ' _5»

ft
02

o M

cc "-1 |

oT^" J3
.-g • g

ggr3

^ O

. §,&! .si jMix.

ill

^ °

'ft ° -2 I

H H

•g 1

O 02

ft ft

OQ 02

III

«A f

° &

..„! • .

« c« o o ft'

°^^ ^^
00

H |

o a*
g a

C 2

SOAPS.

it
0 t

W M

O
H

,2_

02 0

*d «

I I

3 S

01 bfl

Co
at

8ll^
111*

|S|a

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i i

I S

MATERIALS.

g wit
Bassi

Br
a.
ure, or by boi
from seeds
or longi/oUa.
sia parkii, a

e inferior kinds are used
oap-making — e.g. :
orgon" — obtained by fer-
ing and boiling in water
ressed cake, or marc, after
ction of the finer kinds,
kimming off the oil.
il of the infernal regions "
mmed off the waste water

p
a

ski

j^fl= lllg- T

,« ^ .3 ^ S -M <u cs ^ I

o -2- s2-

a- 11

•s S o

Illl-i

s| g

SOAPS.

T3
|

'rt
O

o a

MATERIALS. 25

in the retorts after the distillation of common turpentine.
Chemically, it is a mixture of a large quantity of abietic
anhydride or pinic acid (C44H62O4) with a little sylvic
(C20H30O2) and colop/ionic or pimaric acid (C20H3002), a
mixture which, from the nature of the components, pos-
sesses the properties of a weak acid. In making rosin soap,
the alkali becomes merely saturated with these resinous
acids • there is no basic constituent, like the glycerin of the
fats, to displace.

When an aqueous solution of a rosin soap is treated with
•common salt, there is no separation of the soap, as in the
case of soaps made from fats. Rosin soap also differs from
ordinary soap in the circumstance that its hot concentrated
-solution does not gelatinize on cooling.

2. ALKALIES.

The alkalies used in soap-making are soda arid potash,
which are commercially obtainable either as carbonates or
in the caustic state.

Caustic-soda Lyes. — Formerly the soap-maker purchased
the carbonates, and causticized them himself, but the obvious
advantages derivable from obtaining in the first instance
caustic alkalies have led to the frequent abandonment of the
causticizing process in the soap factory itself, especially in
the smaller factories. By this change a saving is effected
in space, plant, time, and labour, and the strengths of the
. lyes * are more under control. It is only necessary to dissolve
the caustic soda or potash in a given quantity of water to
produce lyes ready for use of any required strength.

The following is an outline of the process for preparing
caustic lyes from soda-ash: — Five parts of freshly burnt

* This word is often pronounced lees, and is variously spelt, but
"the orthography adopted is probably the most satisfactory.

24 SOAPS.

lime are laid evenly over the bottom of the vat, and water-
is poured on till it begins to slake. Over this layer is then
immediately spread a layer of six parts of the soda-ash.
Then a second layer of slaked lime is placed above these,
followed by another quantity of soda-ash, and so on. After
standing two hours, the tank is stanched by gradually filling
up with water or weak lye. In about fifteen hours the
plug at the bottom may be loosened, and the first runnings
drawn off. The tank is afterwards again filled up with
water, which is allowed to stand a suincient time, and then
drawn off as second runnings. After this the contents are
turned over into another vat, covered with water, and, after
a little time, again run down. The runnings from this
operation are very weak, and are usually employed instead
of water for filling up the first vats.

The reaction which occurs when soda-ash is causticized
may be represented by the equation —

+ Ca(OH)2 = 2NaHO + CaC03

Sodium Lime Caustic Calcium

carbonate soda carbonate

106 parts 74 80 100.

Caustic-soda lyes may also be prepared from black ash*
The composition of this is given in the Appendix. It will be-
seen that it contains a large number of salts, but that the
chief ingredients are sodium carbonate and calcium mono-
sulphide, these two together amounting to from 50 to 75
per cent, of the whole. By lixiviation, the soluble carbonate
is washed out with the smallest possible quantity of water,
leaving as an insoluble residue the monosulphide, with the
excess of lime and calcium carbonate. Many methods have
been proposed for extracting the soda as thoroughly as pos-
sible, all, however, on the principle of treating the fresh
ash with strong lye, the partially exhausted ash with weak
.lye, and the nearly exhausted ash with water. The follow-

MATERIALS. 25.

ing is a description of the plan devised by the late JAMES
SHANKS, of St. Helens, Lancashire. It is based on the
fact that a solution becomes more dense the more saline
matter it has in solution, and that a column of weak lye of
a certain height balances a shorter column of stronger lye.
The tanks are arranged as shown in Fig. i, and through
them water is made to flow, acting upon the black ash in its.
passage, and thus becoming more and more saturated and
dense in each consecutive vessel of the series, the satu-
rated lye running off from the last tank. The tanks are
2.6 metres long by 2 metres in depth. F is the perforated

FIG. i.

sheet-iron bottom. The tanks are connected with each other
at the top and bottom by the tube T t. "Water may be run
in by the pipes r, r', r", r"', and the lye emptied into the
channel c' by the taps R, R'. As a rule, four lixiviations ar&
sufficient. The working is as follows : — Black ash having
been thrown in until the tanks are nearly filled, water is
run in. After a time fresh water is run in from the same
tap, and the liquor is driven up the pipe T through t into
the second tank. By means of a plug at the upper end of
the pipe the flow can be regulated. The operation is con-
tinued by bringing fresh water upon the exhausted ash and

26 SOAPS.

saturated liquor upon fresh black ash. The average time
for working off a vat is about forty-eight hours.

The process does not thoroughly wash out the sodium
carbonate, about 3 per cent, being still left in the waste.

The saturated lye, diluted, if necessary, to 22° Tw., may be
causticized with milk of lime, about 1 5 cwt. of unslaked
lime being required for every ton of caustic soda to be
obtained. The lye and the hydrate of lime are agitated
thoroughly together by means of a stirrer, and in about
half an hour the decomposition is finished. The reaction is
represented by the equation —

CaO + H2O + Na.COg = 2NaHO -f CaC03.
After the calcium carbonate has settled, the clear caustic
soda lye is run off.

Steam Lyes. — In preparing these, 100 Ib. of soda re-
quire 50 Ib., and 100 Ib. of potash So Ib., of lime. The
proportion of water is 12 parts to i of potash, and rather
less for soda. The previously slaked lime and the alkali
.are introduced into the vat and boiled by a current of
steam for several hours, until a portion taken out and left
to repose shows that the whole of the alkali has been caus-
ticized by not effervescing on addition of hydrochloric acid,
or by remaining clear on addition of lime-water. The mix-
ture is then allowed to repose till the calcium carbonate
deposits, and the supernatant liquor is drawn off into the
.alkali tank. The residue is then stirred up with fresh
water, and the weak liquor thus obtained may be used to
dilute stronger lyes, or instead of water in another boil.

By this method the decomposition of the sodium car-
•bonate is very thorough, and, as lime is less soluble in hot
•than in cold water, the resulting lyes contain rather less
lime than if made in the cold.

Caustic-potash Lyes may, when desired, be prepared in
same way as the caustic-soda lyes.

MATERIALS. 27

To preserve lyes it has been suggested * to throw upon
the surface of the yet warm lyes a sufficient quantity of
paraffin to cover, when melted, the whole surface, and
thus form a layer which will completely shut out carbonic
acid. No special vessels are necessary, arid the paraffin can
be used repeatedly for the same purpose.

Testing Soda-ash. — In England the equivalent of
sodium is taken as 24, in commercial analyses, instead of
23, and that of sodium carbonate, 108, instead of 106. The
comparison between English degrees and the French, or
DECROIZILLES', degrees is shown in the Appendix.

Soda-ash is sold according to the percentage of available
soda, calculated as sodium carbonate, which it contains — at
so much per degree, or per unit. This percentage is arrived
at by neutralizing with standard sulphuric acid a solution
of a known weight of the ash in hot water — sodium hydrate,
aluminate, and silicate all testing, in this way, as carbonate.
It is unnecessary here to enter into the details of the process,
as these, together with the tests for the impurities, such as
chlorides, sulphides, sulphates, &c., will be found fully
described in general works on practical chemistry.

Sodium Silicate. — SOLUBLE GLASS (Na2Si03.80H2). —
The use of sodium silicate in the manufacture of soap is due
to Mr. SHERIDAN, who took out a patent for the invention
about 1835. His process for the preparation of this silicate
is essentially as follows :t — A mixture of i part of sand
with 3 parts of soda is heated to fusion in a reverbera-
tory furnace. The product of this operation is then drawn
out into water, and dissolved therein by the aid of heat. If,
instead of sand, flint or quartz is the silicious material, it is

* CRISTIANI, " Technical Treatise on Soap and Candles," p. 254.
f MUSPRATT, " Dictionary of Chemistry," ii. 885 ; WATT, "Art of
Soap-making," p. 30.

28 SOAPS.

first calcined, and then powdered by wet grinding with hori-
zontal stones. The impalpable powder obtained is thinned
out with water, and then boiled for about eight hours
with caustic-soda lye of 30° Tw. (sp. gr. 1.15). When the
mass becomes homogeneous, the operation is finished. It is
called, technically, detergent mixture) and is ready for mix-
ture with soap paste.

GOSSAGE'S METHOD.* — Mix 9 parts of soda-ash of 50
per cent, with n parts of clear sand or powdered quartz,
and fuse the mixture in a reverberatory furnace provided
with a tap-hole through which the finished product may be
run off. The product is received in metallic moulds, or in
moulds formed of damp sand. The charge for a furnace
having a bed of 60 square feet area is about a ton of the
mixed sand and alkali, and each charge requires about four
or five hours to be properly fused and combined. It is
always desirable to use such proportions of alkali and sand
for the production of the silicate that the latter may be
almost wholly soluble in water. When the alkali is defi-
cient, however, such is not the case, and to obtain perfect
solution it is then necessary to use as the solvent a solution
of caustic soda or potash. To effect its solution, the silicate
is first ground to powder, and then heated in water, steam
being introduced into the water to keep up the temperature.
When nearly all is dissolved, the undissolved matters are
allowed to subside, and the solution, transferred to a cast-
iron evaporating pan, is concentrated by the application of
heat till it has a specific gravity of about 1.45, when it
becomes viscous on cooling, and is then in a condition to be
added to the soap.

The solution of sodium silicate which is usually supplied
to soap-makers is composed of silicic acid and soda in various

* MUSPRATT, ii. 885.

MATERIALS. 29

proportions, and is of two kinds, the neutral and the caustic.
The neutral silicate has a specific gravity of about 1.37—1.45,
and contains —

Water .... about 65 per cent.
Silicic acid . . . ,, 26 ,,
Soda and impurities . . ,, 9 ,,

The caustic silicate has a specific gravity of about 1.7,
and contains —

Water .... about 43 per cent.
Silicic acid . . . ,,33 „
Soda and impurities . . ,, 24 ,,

Potassium Silicate. — For admixture with soft soaps
the soluble glass is formed by the fusion of a mixture of
equal parts of sand and dry potassium carbonate (or pearl-
ash) in the same way as in the preparation of sodium
silicate. No compound of definite composition is known.*

Soap-makers, however, generally obtain a viscous mass
of the alkaline silicate, which they reduce with hot water
to any strength they require.f

DUNN'S PROCESS. — By means of the apparatus represented
on p. 65, Fig. 10, either silica itself or an alkaline silicate
is made to unite with soap under steam pressure. The
crushed flint or quartz is introduced into the boiler with
caustic-soda or potash lye in the proportion of i cwt. of the
former to 100 gallons of the latter at 21° B. (32° Tw. —
sp. gr. 1. 1 6). The whole is then heated to about 310° F.
and kept under a pressure of 50 to 70 Ib. to the square inch
for three or four hours. The alkaline silicate so obtained
is then discharged, and cooled down. It is then ready for
mixing with the soap paste in the boiler or pan, before the
latter has become cold.

* FRANKLAND and JAPP, " Inorganic Chemistry," p. 466.
f WATT, " Art of Soap-making," p. 31.

30 SOAPS.

WAY'S PROCESS. — The following is the description of this
method as given in the specification of the patent :-—

" I put into a suitable pan, heated by steam or in any
convenient manner, a quantity of caustic alkaline lye (potash,
or soda, or both, as the case may be) of about 18° Tw., so
that the silica solution when made shall have a gravity
as nearly 36° as possible, and, having raised this lye to
the boiling point, I add by degrees the rock or clay "
(found in Surrey, and containing sometimes as much as
70 per cent, of silica), "either in small pieces or ground to
powder, until the alkali has taken up as much silica as it
will dissolve. The heat is now withdrawn, and the undis-
solved earthy matter is allowed to settle. The clear liquor
is run off, and a fresh quantity of water is added to the
sediment to wash out further portions of soluble matter.
The liquors so obtained are solutions of alkaline silicates.
The quantity of rock or clay required will vary with the
percentage of soluble silica which it contains. I find it
necessary for every 31 parts of actual soda, or 53 parts of
carbonate of soda rendered caustic, to employ as much of
the rock or clay as contains 78 parts of soluble silica.

" I produce similar alkaline silicates from the rock or
clay by gently heating it in a furnace with alkalies or alka-
line carbonates. In this case, combination of the materials
and production of the alkaline silicates takes place at a tem-
perature much below that which is necessary when other
forms of silicious matter are. used, and, though preferring
the method formerly mentioned for the treatment of the
rock or clay, the one last described may be employed. The
alkaline silicate is dissolved out from the f urnaced materials
by water or alkaline lye.

" I prefer, in either case, to saturate the alkali as fully
as possible with silica, but this is not absolutely necessary.
The silicates so produced are more suitable for the soap-

MATERIALS. 31

maker, for the following, amongst other, reasons : —
(i) They are more economically produced ; (2) The caus-
tic property of the alkali contained in them is more per-
fectly neutralized ; (3) They contain no iron, alumina, or
other matter injurious to the soap ; (4) The soap produced
by them is therefore of superior quality, as well as
cheaper.

" The alkaline silicate produced by either of these pro-
cesses may be employed in any of the modes now used by
soap-makers in incorporating the silicates of the alkalies
with soap."

Sodium Aluminate (Na2 A1204 *). — BONAMY, of St. Ger-
mains, near Paris,f seems to have first suggested the use of
this material in the fabrication of soap.

The two chief substances from which sodium alumirfate is
prepared are bauxite and cryolite. Bauxite ( (AlFe)205H4)
is an aluminate of iron. This is calcined with soda-ash, and
the resulting sodium aluminate is separated from the iron
oxide by lixiviation. The dry commercial salt has the follow-
ing composition : —

Soda 43 parts

Alumina . . . . . . 48 ,,

Water and impurities . . . 9 ,,

100 ,,

Cryolite (6NaF.Al2F6) is a double fluoride of sodium and
aluminium. From this the soap-maker may prepare his
own aluminate, either by boiling the finely powdered mineral
with lime, when insoluble calcium fluoride is formed and the
alumina is dissolved in the excess of soda, or by calcining the
mixture of cryolite and lime in a reverberatory furnace and
afterwards lixiviating. •

* KOSCOE and SCHORLEMMER, "Treatise on Chemistry," vol. ii.
pt. i. p. 445.

t "Polytech. Centralblatt," 1865, s. 1452.

32 SOAPS.

Natrona refined saponifier is the name under which the
Pennsylvania Salt Manufacturing Company of Natrona,
U.S.A., send out, in boxes, a white dry powder prepared
from cryolite, and having, according to DUSSAUCE,* the
following composition : —

Soda 44 parts

Alumina 24 ,,

Water 32 „

100 „

Water. — The character of the water employed in soap-
works is not a matter of indifference. Hard waters should
be avoided, or softened before use, as the salts of lime and
magnesia form insoluble soaps in the pan, and not only waste
the fatty matters, but interfere with the appearance of the
finished product. Suspended impurities may be removed
by subsidence or filtration.

PRELIMINARY TREATMENT OF RAW FATTY
MATERIALS.

Many soap-makers render, or clarify, their own fatty
materials, insuring in this way greater uniformity in the
purity of their goods.

I. Rendering Animal Fats.

i°. DRYING AND MINCING. — The rough fats are hung up
to dry in a well-aired room, and are then minced, either, as
in large establishments, by steam-driven machinery or, as
in small works, by a lever-knife fixed upon a table.

2°. BOILING. — On a small scale this is done in an open
boiler or copper. It is essential that the fire should only
come in contact with the bottom of the vessel, to avoid the
risk of burning and darkening the fat. A quantity of pre-

* " General Treatise on the Manufacture of Soap," p. 750.

MATERIALS. 33

viously rendered fat is first put into the boiler, and after-
wards the minced tallow to be operated upon ; when the first
is melted, the entire contents are stirred together till the
whole of the fat is extracted. "When this is accomplished,
the melted fat is removed, and, after passing it through a
sieve, such as a wicker, or wire basket, or brass-wire sieve,
and allowing it to rest for some time to deposit further im-

FlG. 2.

purities, it is finally, before solidification commences, dis-
tributed into store casks, or, if required for immediate use,
conveyed direct to the soap pan.

The solid residue, called greaves or cracklings, is subjected
to heat and pressure, and a further quantity of fat is ob-
tained.

34 SOAPS.

A convenient form of press for this purpose, made by the
Boomer and Boschert Press Company, Syracuse, N.Y., is
shown in Figs. 2 and 3.

The hoop is composed of a cast-iron section bolted to the
base of the press, to which are hinged two doors completing

FIG. 3.

the circle. These doors are composed of wrought-iron bands
to which are riveted the perpendicular staves, with a space
of about |th inch between each. The ends of the bands
are turned outwards and a steel clamp slipped over them,
locking them securely together. The base has ribs cast on

MATERIALS. 35

"the upper surface, over which, inside the hoop, is placed a
plate perforated with holes. After being pressed, the clamp
is removed and the doors swung open (see Fig. 3), leaving the
cracklings free for removal, and avoiding the heavy labour
connected with the ordinary form of hoop. A patent pres-
sure indicator is attached, and shows the amount of pressure
being put upon the scrap. A cast follower, attached by a
heavy screw to the platen, may be raised or lowered, to
suit the amount of material in the hoop, and obviates the
necessity of wood-blocking.

It is desirable to render separately the various kinds of
<crude fats, so as to secure uniformity in the quality. The
fats also should be tolerably fresh, otherwise the rendered
products are apt to be rancid and discoloured.

As a maximum product which is seldom attained,* beef
.suet yields 95 per cent, of tallow and 2 per cent, of refuse,
mutton suet 91 per cent, and 4.5 per cent, of refuse.

The chief objections to this method are: — (i°) The diffi-
•culty of keeping the heat uniform throughout; (2°) The
•cellular tissue is not thoroughly broken up, and becomes so
hard that the subsequent action of the press fails to squeeze
<out the whole of the retained fat; (3°) The extremely objec-
tionable odours evolved.

Other means have, therefore, been devised, such as the use
-of steam instead of the open fire ; the more effectual break-
ing up of the fatty cells by mechanical power, or by D'ARCET'S
dilute sulphuric acid treatment ; the employment of a hood
fitted with a pipe to convey the vapours through the fur-
naces ; and the use of steam-tight cylinders in place of the
open boiler.

In D'ARCET'S method the crude fat is boiled by steam
"with about one-fourth its bulk of water, acidulated with

* RICHARDSON and WATTS, " Technology," vol. i. pt. ii. p. 423.

D 2

36 SOAPS.

2—3 per cent, of sulphuric acid, in an open, or loosely covered
lead-lined vessel. The fats so rendered are whiter than'
those purified by the older method.

A very effective steam-tight cylinder is shown in Fig. 4?

FIG. 4.

which is highly spoken of by MOKFIT. Its capacity is from
1200 to 1500 gallons, and it is made of strong iron, or
boiler-plates riveted together. The height of the cylinder
is two and a half times greater than the diameter. The-

MATERIALS. 37

method of working the apparatus is as follows :* — The false
bottom being arranged in its place and the discharging hole
•closed up, the cylinder is filled through the man-hole with
the rough tallow, or lard material, to within 2| feet of the
top. This done, the man-plate, K, is securely fitted into
the hole, H, and steam let on from an ordinary boiler
through the foot-valve into the perforated pipe, c, within
the tank. The weight on the valve is set at the required
pressure, and, during the steaming, the state of the contents
is frequently tested by opening the test-tap, R. If the
quantity of condensed steam is too great, it will be indicated
by the ejection of fatty matters. In such case the regu-
lating cock, x, must be opened, and the condensed steam
drawn off into the receiving tub, T, until the fatty matter
ceases to run from the tap, R. After ten to fifteen hours'
continued ebullition, the steam is shut off, and the excess of
uncondensed steam in the cylinder allowed to escape through
B and the safety valve. After sufficient repose, the fatty
matter separates entirely from water and foreign admixture,
and forms the uppermost stratum. It is drawn off through
the cocks, p p, in the side of the tank, into coolers of ordi-
nary construction. After the fat has been thus removed
from the cylinder, the cover, F, is raised by means of the
rod, G, from the discharging hole, E, and the residual
matters at the bottom fall into the tub, T. If, on inspec-
tion, any fatty matters are found in this tub. they should
be returned to the tank with the next charge.

The pressure of steam may be from 50 to 60 or 70 Ib. per
square inch, but a pressure beyond this is apt to injure the
tallow, and cause a proneness to decomposition.

It is stated that the steam-cylinder process extracts about
1 2 per cent, more tallow, or 6 per cent, more lard, than any
other method.

* MUSPRATT'S

' XJNIVEBSITl

38 SOAPS.

An illustration is given in Fig. 5 of Merry weather & Sons'"
patent superheating apparatus for rendering fat by steam.

The following advantages are said to be obtained by this
apparatus over the method of melting by fire-heat : — (i ) The-

FIG. 5.

a is the superheater, formed of wrought-iron lap-welded tubes, set
in a brick oven with ordinary furnace and bars, as shown.

I is the steam boiler, the water in which is kept to its proper level
by means of a self-regulating feed.

c is the chimney.

d d are the pipes and cocks connecting the boiler with the super-
heater.

f/ is the pipe which connects the superheater with

h, the fat-pan, which is set in brickwork, to prevent loss of heat.

In cases where it is essential to destroy the obnoxious fumes
arising from the melting process, a patent cover is provided for the
fat-pan, 7*.

copper is not injured by local heat, and will last for many
years ; (2) There is little risk of burning the tallow or fat
during the heating; (3) The pan costs 50 per cent, less-
than those ordinarily used ; (4) The heat can be instantly

MATERIALS. 39

checked, thus preventing the danger of boiling over ; (5) No
risk of accidents from fire; (6) Economy of fuel.

Glue fat often contains 2 or 3 per cent, of lime. The
presence of lime can be easily ascertained by stirring up a
little of the melted fat with a solution of ammonium oxalate
or of oxalic acid. If no lime is present, the liquid under the
fat remains clear. Lime causes the fats, when saponified,
to become spongy, in which state its separation can only be
with difficulty accomplished by means of common salt. It-
is therefore desirable, before using such fat for soap-making,
to treat it with dilute sulphuric acid.

II. Bleaching.

There are various ways of decolorizing the fatty matters
used in soaperies. The BICHROMATE METHOD OF WATT,
which is very generally followed for palm oil, is as follows : —

i°. The oil or fat is melted in a copper, and the dregs
are allowed to subside.

2°. The oil, now at about the temperature of 120° to
130° F., is run off from the dregs into another vessel, and
treated with a mixture of potassium bichromate and hydro-
chloric acid. For i ton of fat the following quantities
are used : — 25 Ib. of the bichromate, dissolved in boiling
water, are first poured into the melted oil, with constant
stirring, and, after thorough admixture, 60 Ib. of hydro-
chloric acid are added, and the mixture constantly stirred till
it acquires a uniform greenish tint, or till the fat is sufficiently
decolorized. A little more of the bleaching materials may
be added if necessary. After this the whole is well washed
with hot water and allowed to settle. In about twelve
hours the green liquor, as it is called, containing chromic
chloride and hydrochloric acid, may be drawn off, and the
bleached oil removed. The reaction which takes place may,

40 SOAPS.

for the sake of simplicity, be represented in two stages,
though actually both take place at once —

(a) K2Cr207 + 2HC1 = 2KC1 + OH2 + 2Cr03

Potassium Hydrochloric Potassium Water Chromic
bichromate acid chloride anhydride.

The chromic anhydride thus liberated is at once attacked
by more hydrochloric acid, with the production of chromic
chloride and free chlorine —

(5) 2Cr03 + I2H01 = Cr2Cl6 + 60H2 + 3C12.

This result may be represented by a single equation, as
follows : —
K2Cr2Or + I4HC1 - Cr2Cl6 + 2KC1 + yOH, + 3C12.

The theoretical quantities are as nearly as possible equal
proportions of the acid and bichromate, but, in practice, to
insure completeness, a large excess of the acid is used — two
or three times the weight of the bichromate.

NITRIC ACID was at one time employed for bleaching palm
oil. The objections to its use are that it bleaches imper-
fectly, and to a great extent destroys the peculiar and
characteristic violet odour.

CHLORINE, generated from manganese dioxide and hydro-
chloric acid, or from manganese dioxide, sodium chloride,
and sulphuric acid, has been much used for bleaching this
oil. The ingredients are mixed with the melted fat. The
following equations show the reactions which take place : —
Mn02 -f 4HC1 = C12 + MnCl, + 2H20

Manganese Hydrochloric Chlorine Manganese Water;
dioxide acid chloride

Mn02 + 2lSTaCl + 2H2S04 =

Manganese Sodium Sulphuric

dioxide chloride acid

Cl, + MnS04 + Na2S04 + 2H20

Chlorine Manganese Sodium Water,

sulphate sulphate

The efficacy of chlorine as a bleaching agent is con-

MATERIALS. 41

sidered to depend upon its affinity for hydrogen. Dry
chlorine gas will not bleach, but, if water be added, the
action at once commences. The chlorine takes hydrogen
from the water, and liberates oxygen in the nascent state,
which, in this condition, readily unites with vegetable
colouring matters to form colourless compounds. The
immediate bleaching agent is, therefore, oxygen.

Another way of employing chlorine is in the form of
chloride of lime, or UeacJiing poivder (calcic chloro-hypo-
chlorite, Ca(OCl)Cl, or, according to another view, a mix-
ture of calcium chloride, CaCl.,, and calcium hypochlorite,
CaCl202). The gently heated oil is stirred for some time
with about i per cent, of good chloride of lime previously
made into a milky liquor by trituration with water ; about
i \ per cent, of sulphuric acid diluted with twenty times its
weight of water is then added, and the agitation renewed
and maintained for at least two hours; it is, lastly, well
washed with steam or hot water.

The objection to the use of chlorine, or of chlorides, is
that, although the colouring matters are readily destroyed
in the way mentioned, the chlorine acts injuriously upon the
fat, probably on account of its affinity for its hydrogen, and
is very apt to produce a brownish tint.

DUNN'S method is effective and simple, and applicable to
palm and other oils. The fat or oil is heated to 180°— 200° F.,
and then air is forced through the melted materials, by
means of a blowing apparatus, in numerous small streams.
The vat in which the operation is conducted is furnished
with a hood, communicating with a chimney, to convey
away the unpleasant vapours given off. When the fat is
sufficiently bleached, it is washed with steam or hot
water.

Tallow. — Commercial tallows very often require further
purification, especially before use in candle-making. The

42 SOAPS.

following has been recommended as a good process for
bleaching tallow :* — 1°. About 50 Ib. of caustic-soda lye are
placed in a clean boiler, and the steam turned on. Salt is
then added to the lye till it shows a density of 25° to 28° B.
2°. 300 Ib. of tallow are now placed in the boiler and heated
to boiling. It is allowed to boil up about i or 2 inches
only, and then left for from three to five hours to clarify.
3°. At the end of this time the upper saponified layer is
ladled off; the purer tallow is removed and passed through
a hair sieve into a clean vessel, until the lower saponified
layer is reached. The residue in the boiler, consisting of
saponified fat and lye, together with the upper layer, may
be used in the preparation of curd soap. 4°. The boiler
having been thoroughly cleansed, about 30 to 35 Ib. of water
with | Ib. to i Ib. of alum are placed therein and heated
to boiling. To this solution the fat is added, and the whole
is boiled for about fifteen minutes, till the filth has dis-
appeared from the fat. Transferred after this to another
vessel, it is left to itself again for from three to five hours.
5°. The fat obtained from this operation is again placed in
the boiler and heated to the temperature of 170° to 200° C.
In this last treatment the fat becomes snow-white and fit
for use. The steam must be turned off as soon as the
slightest disagreeable odour is emitted, whether the tempera-
ture be 150° or 170° C., otherwise the fat will again turn
dark.

Freshly rendered, sweet fat is most readily bleached, and
may be heated quite high. Still, the fat used should not
be too fresh, or there will be risk of saponifying the whole
of the 300 Ib. without leaving any to bleach.

Tallow which has been treated in this way, when used in
toilet soaps, gives them a white colour and agreeable odour.

#—

* "Oil Trade He view," Oct. 1884.

MATERIALS. 43

Such tallow is also well adapted for candle-making, as it
becomes exceedingly hard.

III. Bone-boiling.

This is an operation sometimes performed on the soapery
premises.

The bones are first sorted out, and those which are
unsuitable for the manufacture of articles of bone are
crushed by suitable machinery. The bones are placed in
boxes, or cradles, made of iron bars, or of perforated iron,
and lowered in this way into the boilers. In these vessels
the bones are boiled in water heated by steam. The steam
is injected as long as any appreciable quantity of fat gathers
on the surface of the water. This is then skimmed off, and,
without further purification, is available for soap-making.
The extraction of fat in this way is always imperfect, about
6 per cent, of the fat remaining behind in the bones. On
an average, from 2 to 4 per cent, of grease is obtained, or
from select fatty bones about 6 per cent.

SELTSAM'S method.* — By this means bones of all kinds
may be extracted, yielding double, or even triple, the quan-
tity of fat obtained by the above process, and of superior
quality. The apparatus consists of a strong wrought-iron
cylinder of about 370 cubic feet capacity. The cylinder is
filled with bones through a man-hole at the top, except a
space, 8 inches in depth, at the bottom, separated from the
bone-chamber by a perforated false bottom. In this space
there is placed a coil of pipe, through which steam can be
passed. Petroleum spirit is let into the bottom of the
chamber, till it stands about 18 inches high. This spirit,
boiled and vaporized by the steam coil, gradually rises
amongst the bones, expelling the air, and, after about an

* English patent 2976—1881 ; " Jour. Soc. Chem. Ind." 1882, p. 112.

44 SOAPS.

hour, there is perceptible at the man-hole a smell of petro-
leum. The man-hole is then closed, and the remaining air
and aqueous vapour pass through a pipe at the top of the
cylinder through the condenser. In a little while, petroleum
spirit alone runs out, and then the cock is shut, and pres-
sure allowed to accumulate in the bone-chamber to the
extent of about 22 Ib. above atmospheric pressure. Steam
is then shut off, and the whole left to cool slowly. After a
sufficient interval, or next morning, steam is again let into
the lower coil, till a pressure of 7 J Ib. is attained. By this
means most of the petroleum spirit is again vaporized
among the bones, and all the fat is collected below the dia-
phragm. The fat is next drawn off and introduced into
the still. Steam is again let into the cylinder, the cock
into the condenser opened, and the petroleum spirit forced
out into the latter. The condensed petroleum spirit and
water are received into a covered tank. The water is
allowed to siphon off through a pipe at the bottom of the
tank, and the spirit, as it collects on the surface of the
water, passes through a pipe at the side to the petroleum-
spirit tank. "When no more petroleum spirit comes through
the condenser, the steam is shut off, and the bones emptied
through a man-hole just above the false bottom. The
grease, in the meanwhile, is heated in the still, the spirit
distilled off, and run back into the tank. The grease is
then run out, and will be found to be sweet.

After this treatment the bones are almost chemically free
from fat,, and may be crushed and calcined for charcoal.
The smaller fragments, instead of being calcined, may be
used for the production of glue, and the mineral matter
remaining may be sold or made into superphosphate.

GXHAPTER III.
HYDROMETERS AND LYE-TESTI3STG.

THEORY OF THE HYDROMETER. — It is one of the laws of
hydrostatics that a body immersed in a fluid is buoyed, or
pressed upwards by a force exactly equal to the weight of
the bulk of the fluid which it displaces. Hence, if the body
float, the weight of the volume of liquid which would fill
the space occupied by the portion immersed is exactly equal
to the entire weight of the body itself. Upon this simple
fact the whole theory of hydrometry rests.

Hydrometers may be constructed of glass, silver, copper,
brass, or German silver. The great economy of glass, its
perfect cleanliness, resistance to corrosion, incapability of
fraudulent change of form or weight, and facility of manu-
facture, are qualities possessed to the same extent by no
other known substance. The chief objection to the glass
hydrometer is its fragility, and this often renders metallic
instruments preferable. Metallic hydrometers should be
gilded with gold or platinum, so as to be rendered incapable
of corrosion by liquids generally.

A hydrometer, whether of glass or metal, is simply a
hollow bulb, carrying a graduated stem above, and having,
below, a counterpoise, or ballast, to preserve it in stable
equilibrium when in a vertical position.*

* For details as to the mode of construction, see " Keports from

46 SOAPS.

In order that a hydrometer may be convenient and use-
ful, it is not necessary that it should show specific gravities,
and it is, perhaps, not desirable that it should do so, for it
is easier to remember, for instance, that a solution has the
density of 20° Baume", than that its specific gravity is
1.1515. Hence we find that in France, though BRISSON
brought forward an instrument reading specific gravities,
and succeeded in causing a violent opposition to BAUME'S
hydrometer, the latter came into general use, not merely
in France, but also in our own and in other countries of
Europe. But no doubt the difficulty of construction, and
consequent high price, of an instrument based ori rigid
scientific principles also contributed to BRISSON'S hydro-
meter being superseded by one which, though constructed
on arbitrary rules, is simple, easy of construction and use,
and economical.

The forms of hydrometer chiefly used by soap-makers are
BAUME'S on the Continent and TWADDELI/S in England.

BAUME'S HYDROMETER. — For fluids lighter than water,
BAUME invented a spirit hydrometer (p$*e-e*prit, Fr. ;
Branteweinmesser, Ger.), and for fluids heavier than water
his hydrometer for acids and saline and saccharine solutions
(pese-acide, pesfrsel, or pese-sirop, Fr. ; Sauremesser, Salz-
spindel, or Zuckermesser, Ger.). These instruments are en-
tirely distinct, and form no part of a common system, being
constructed on different bases. The degrees of one are not
equal to those of the other, and the zero point of the pese-
esprit, determined by a solution containing 10 per cent, of
common salt, corresponds in the pese-acide to the density of
pure water.

The pese-esprit is constructed by immersion in a 10 per

the Secretary of the Treasury of Scientific Investigations in relation
to Sugar and Hydrometers," by Prof. R. S. McCuLLOcn (Washing-
ton, 1848).

HYDROMETERS AND LYE-TESTING.

•cent, solution of common salt to obtain the zero point. Then
it is floated in water to determine another point, which
BAUME called 10°. The interval is graduated equally, and
the scale is extended by laying off repeatedly, with a pair of
dividers, corresponding intervals on the stem.

The zero point of the pese-acide is given by the surface
of the distilled water in which it floats. Immersion in a
1 5 per cent, solution of common salt fixes the point which
is to be marked 15° upon the scale. Hence, i° B. = i per cent,
of salt. Degrees beyond 15° are determined by the same
process of extension employed for the pese-esprit.

Results of Different Observers, obtained by Experimental Com-
parison of BAUME'S Hydrometer ivith Specific Gravities
at 54.5° F.
(Pese-acide, or Hydrometer for Liquids heavier than Water.)

Decrees B.

FBANCKEUB.

DELKZEITNES.

GH.PIH-.

1. 0000

.0000

.000

I.O2OI

.0209

.020

I.O4II

.0448

.040

1.0630

.0687

.064

1.0857

-0937

.089

I.I095

.1200

.114

I-I343

•1475

.140

I.I603

.1764

.170

I.I875

.2068

.200

1. 2l6o

.2389

.230

1-2459

.2727

.261

1-2773

•3083

•295

I.3I03

•3333

•333

I-345I

•3861

•373

1.3818

.4285

.414

1.4206

•4735

•455

1.4615

•5217

.500

I-495I

•5730

-547

.6279

•594

1. 6OOO
1.6522

.6868

•659

.717

1.7070

!8i84

•779

1.7674

.8922

.848

I-83I3

.9721

.920

1-8537

2.0003

SOAPS.

The differences in these results are generally accounted
for by differences in the accuracy of the hydrometers used.
The following is the table generally used for converting the
reading of BAUMK'S degrees into specific gravities : —

Comparison of the Degrees of BAUME'S Hydrometer with the

Real Specific Gravities at 54.5° F. (FRANCCEUR).

(For Liquids heavier than Water.)

Specific
Gravity.

i. oooo

• 1515

•3451

1.6170

.0066

.1603

•3571

1.6344

•0*33

.1692

•3694

1.6522

.0201

• 1783

• 3818

1.6705

.0270

•1875

•3945

1.6889

.0340

.1968

.4074

1.7070

.0411

.2063

.4206

I-7273

.0483

.2160

•4339

1.7471

•0556

.2258

.4476

1.7674

.0630

•2358

•4615

1.7882

.0704

3°

• 2459

•4758

1.8095

.0780

•2562

.4902

.0857

.2667

•4951

1.8537

•0935

•2773

.5200

1.8765

.1014

.2881

•5353

1.9000

.1095
.1176

.2992
•3103

•5510
•5671

, 73

i 74

1.9241
1.9487

.1259

•3217

.5833

1.9740

•I343

•3333

.6000

2. OOOO

.1428

TWADDELL'S HYDROMETER. — This hydrometer is a good
deal used in this country by soap-makers. The instrument
is so graduated that the real specific gravity can be deduced
easily from the hydrometer degree by multiplying the latter
by 5 and adding 1000 — the sum is the specific gravity, water
being 1000. Thus 10° Tw. x 5 + 1000 — sp. gr. 1050, or
1.05 ; 15° Tw. x 5 + 1000 = sp. gr. 1075, or 1.075 — or, in
other words, i° Tw. is equal to five degrees of gravity.

In hydrometric determinations the temperature of the
sample must be carefully attended to, as fluids expand as
the temperature is increased. Hydrometer tables used in

HYDROMETERS AND L YE-TESTING. 49

England are generally adjusted to the standard tempera-
ture of 60° F., but, when tables giving the correction for
variation of temperature are not accessible, the fluids to be
examined must be brought, by cooling or heating, to this
temperature.

Unless lyes are made from pure alkalies, the indications
of the hydrometer do not accurately give their strength.
This can then be only correctly determined by the process
of alkalimetry, in the way described in textbooks on practical
chemistry.

CHAPTER IV.
S AP ONIFIC ATION.

WHEN a solution of an alkali, such as soda or potash, is
gradually added in the cold to an acid, such as nitric acid?
the intensity of the acidity of the latter gradually diminishes
till at length a point is reached when the mixture ceases to
affect either blue or red litmus-paper. We say that the
acid has been neutralized by the alkali added — it has ceased
to be free acid, having entered into combination with the
soda or potash to produce sodium or potassium nitrate.
Such a compound we call a salt. The reaction whicn takes
place is represented by the equation —

(a) HN03 + KHO - KN03 + H20

Nitric acid Potash Potassium Water;
nitrate

but there are several other ways in which salts may be
formed — e.g. :

(b) Union of elements —

K2 + C12 - 2KC1

Potassium Chlorine Potassium chloride.

Na2O + C0a = Na2C03

Soda Carbonic Sodium

acid carbonate.

(d) Action of add on a metal —

H2SO4 + Zn - ZnS04 + H2

Sulphuric Zinc Zinc Hydrogen.

acid sulphate

SAPONIFICATION.

(e) Double decomposition between two salts —

(1) BaCl2 + Na2HP04 - 2NaCl + BaHPO4

Barium Acid Sodium Acid

chloride sodium chloride barium

phosphate phosphate.

(2) AgN03 + NaCl = AgCl + NaN03

Silver Sodium Silver Sodium

nitrate chloride chloride nitrate.

(f) Displacement of the acid or base in a salt by another
acid or base —

(1) BaCl2 + H2S04 = BaS04 + 2HC1

Barium Sulphuric Barium Hydrochloric

chloride acid sulphate acid.

(2) K,S04 + Ba(HO), = BaS04 + 2KHO

Potassium Barium Barium Potassium

sulphate hydrate sulphate hydrate.

The simplest- example of soap-making, which, however, is
not strictly saponification, is afforded by the union under
the influence of heat of a, free fatty acid, such as oleic acid,
with an alkali. This may be thus represented : —

C17H33.CO(OH) + NaHO = C17H33.CO(01Sra) + H2O

Oleic acid Caustic Sodium oleate Water.

soda (soap)

It will be at once seen that the fatty acid and the soda have
united so as to produce a salt, just as the nitric acid and
potash in example (CL) above.

The oils and fats, 'however, used by the soap-maker are
not acids, and the explanation of their saponification is
therefore not quite so simple. CHEVREUL, by his researches,
extending from 1813 to 1823,* demonstrated the true
nature of the animal and vegetable fixed oils and fats, and
to him we are indebted for the right understanding of what
takes place when a fatty body is saponified. He showed
that fats are compound bodies, formed from an organic
base, glycerin (glycerol), and various fatty acids, thus consti-
tuting true salts. Thus, mutton and beef fat are chiefly

* "Keclierches chirniques sur les Corps gras " (Paris, 1823).

E 2

52 SOAPS.

glyceryl + stearic acid ; palm oil is chiefly glyceryl + palmitic
acid; olive oil, glyceryl + oleic acid. These compounds are
neutral salts, ethereal salts or glycerides. The glyceride of
stearic acid is also called stearin; that of palmitic acid,
palmitin ; and that of oleic acid, olein. Oleiii is liquid, and
the other two glycerides are solid, at ordinary temperatures.
Stearin has the highest melting point. Hence, the softest
fats are those which contain most olein, and the hardest
those which contain most stearin. Mutton and beef tallows
and lard are rich in stearin. Palm oil is rich in palmitin.
Sperm and cod-liver oil contain a large proportion of olein.
The fatty acids in these glycerides have less affinity for the
glyceryl than they have for alkalies. Hence, when a fat is
heated with an alkali, and saponified, the basic constituent,
or glyceryl (as the radical C3H5 is termed), is displaced by the
alkali, which unites with the fatty acid, or acids, previously
combined with the glyceryl, and a new salt (soap] is formed,
as in the last example of the formation of a salt (/, 2) given
above, thus : —
C3H;,(C16H310.,)3 + 3NaHO = 3Na(ClcTI31Os)-fC3H5(HO)3

Palm oil, or tripalmitin Caustic Palm soip, or Glycerol or

soda sodium tripahnitate glycerin.

Actually what takes place in saponincation is not so
simple, because each of the various oils and fats contains
several glycerides, either mixed or in chemical combination.*
Thus it follows that the potassium or sodium salts resulting
from saponincation must also contain several fatty acids.
Ordinary hard soap, for instance, is a mixture of sodium
stearate, palmitate, and oleate.

The production of soap by the combination of oleic acid
with an alkali, or of resinous acids with an alkali, is not
strictly saponification, which term is, scientifically, confined

*" Churchill's Technological Handbooks" — "Oils and Tar-
nishes," p. 12 ; BELL'S " Chemistry of Foods," pt. ii. p. 44.

SAPONIFICATION. 53

to the decomposition of ethereal salts, such as the ordinary
fats, by an alkali. Hence, the term saponification is ex-
tended to include the decomposition of any ethereal salt by
mi alkali. For instance, when ethyl acetate (an ethereal
salt) is decomposed into acetic acid and alcohol, saponifica-
tioii takes place, thus —

CH3CO.OC2H5 + NaHO .= CH3CO.ONa + C2H5HO

Ethyl acetate Caustic Sodium acetate Ethyl

soda alcohol,

although sodium acetate is never called a soap.

The production of soap is not, like its decomposition by
an acid, a momentary process, but there are a number of
stages in the operation, each occupying a considerable length
of time, from the first mixing of the fat with the alkali,
when a milky liquid is produced, to the point when the union
between the alkali and the fatty acids is complete. It has
been said that acid salts are first produced, and that these
hold the remainder of the fat in a state of solution or di-
vision until it also is able to combine with the alkali, and
transform the acid into neutral salts ready for use as soap.
This reaction may be easily observed if the fat is boiled
with one-half the requisite quantity of alkali ; the whole of
the oil is at length dissolved, but the solution becomes
turbid on cooling, and, when diluted with water, and boiled,
unsaponified fat separates, which had been retained in the
fluid only by the stearate, palmitate, <fcc., of the alkali
formed.*

DECHAN and MABEN,! however, are of opinion that, as
the fatty acids are monobasic, the formation of acid salts
cannot take place, but that basic oleates, stearates, and
palmitates are first formed, and that, as saponification pro-

* MUSPRATT'S " Chemistry," ii. 875 ; KICHAIIDSON and. WATTS,
•" Technology," vol. i. pt. iii. p. 638.
f " Pharm. Journ." June 13, 1885.

SOAPS.

ceeds, more of the alkali enters into combination, till, finally,
if the operation is properly conducted, a neutral compound
results.

The following tables include the chief fatty acids derived
from natural fats : —

Acetic, or CnH2n+i.CO(OH) Series.

Name of Acid.

Formula.

Equi-
valent.

Melting
Point, C.

Source.

Butyric . C3H7.CO(OH)

88 |

Below

-20°

I Butter.

Caproic

C5Hn.CO(OH)

116

Butter, cocoa-nut oil.

(Enanthylic

CHH13.CO(OH)

130

-10.5

Castor oil.

Caprylic .

C7H15.CO(OH)

144

Butter, cocoa-nut oil.

Capric, or

rutic
Cocinic

C8H19.CO(OH)
C10H21.COVOH)

172
1 86

Butter, cocoa-nut oil.
Cocoa-nut oil, sper-

maceti, Chaulmoo-

gra oil.

Laurie . CnH2VCO(OH) 200

40.5

Cocoa-nut oil, sper-

maceti, laurel but-

ter or bay-fat.

Myristic .

C13H,7.CO(OH)

228

53-8

Muscat fat, Dika

bread, cocoa - nut

oil, spermaceti.

Palmitic .

C15H31.CO(OH)

256

Palm oil. To some

extent in most ani-

mal fats.

Stearic

C^.CCHOH)

284

69.2 | Tallow, suet, lard,

and in most fats.

Arachidic .

C19H39.CO(OH) ! 312

Earth-nut oil.

Behenic, or

benic

CLH43.CO(OH)

340

Ben oil.

Ccrotic . i CMHM.CO(OH) ; 410

Bees'-wax.

Melissic .

(V3..00(OH) ! 452 88

»>

SAP ONI PICA TION.

Acrylic, or CnH2n_ i.CO(OH) Series.

Name of Acid.

Formula.

Equi-
valent.

Melting
Point C.

Source.

Oleic.

C^ CO(OH)

282

J4°

Tallow, suet, lard,

almond, and olive

oils, &c.

Ela'idic* .

C^H^. CO(OH)

282

44-45

Ditto.

Linoleic .

Clb.H2gO2

252

Linseed oil.

Kicinoleic .

C H 02

282

__ •

Castor oil.

Physetoleic

C H 0

254

30°

Sperm oil.

Doeglic

CWK

296

Bottle-nosed whale.

Brassic, or

erucic .

C«H«A

338

33-34

Rape oil.

From the equation given above (p. 52) we learn some-
thing more than merely the change of arrangement which
takes place in the combination. If we add up the various
chemical equivalents in the equation, we shall find that,
taking palm oil as simply tri-palmitin, C3H5(OC16H310)3,
806 parts by weight (oz., lb., cwt., or tons) unite with
120 parts by weight of caustic soda (3NaHO) to produce
834 parts of palm soap, and that 92 lb. of glycerin are set
free. Hence, it is easy to calculate how much soda, or
potash, will be requisite to completely saponify any given
quantity of fat. Inasmuch, however, as palm oil is not
pure tri-palmitin, but contains also tri-olein (the stearin
may be neglected), the actual equivalent of palm oil will be
more nearly that of

Tri-palmitin . C3H,(C16H310,)3 = 806

Tri-olein . C3H5(C18H33O2)3 = 884

1690 -~ 2 = 845

Then, as

("molecular] fequiva-] lb. lb.

845 4 weight of I : 93 -j lent of I : : 100 (palm oil) : 1 1
( palm oil J ( 3NaaO J

of caustic soda (100 per cent. Na20) requisite for the saponi-
fication of 100 lb. of palm-oil.

* Isomeric with oleic acid, from which it is obtained by the action
of nitrous acid.

56 SOAPS.

The proportion of tallow equivalent to 3NaaO is similarly
found to be 887 —

Tri-stearin . C3H5(C18H35O2)3 = 890
Tri-olein . C3H5(C18H3302)3 = 884

and that of cocoa-nut oil, 748, thus : —

Tri-laurin . C^C^O.^ = 638
Tri-myristin . C3H5(C14~H27O2J3 = 722
Tri-olein . CaH^CjgH^O.^ = 884

1774 -~ 2 = 887

2244 4- 3 = 748

Calculating thus, the following proportions are ob-
tained :* —

ioo Ib. of

Kequire of

Soda
(ioo % Na,0).

Potash
(ioo%K,0).

Tallow .....
Palm oil .
Cocoa-nut oil .
Oleic acid (tri-olein)

io.5olb.

11.00

12.43

10.52

15.92 Ib.
16.67

18.86
15.95

As the percentage of available alkali at command is never
ioo, it is requisite to make a correction for the percentage
available. If that were 60 per cent., then the amount of
alkali to be employed for every ioo Ib. of fat would be the
above quantities increased in the proportion of 60 to ioo j
or if it contained 20 per cent, of available alkali, then the
proportion would be five times the above ; and so on.

The quantity of alkali necessary to saponify any fat may
also be found experimentally by KOETTSTORFER'S saponifica-
tion method,t which, after the standard solutions have

* CRISTIANI, " Treatise on Soap and Candles," p. 154.

f For details of the process, see ''Analyst," 1879, p. 106; or
"Churchill's Technological Handbooks" — "Oils and Varnishes,"
p. 246.

SAPONIFICA TION.

been prepared, is simple, accurate, and rapid. The follow-
ing are the figures obtained in this way by KOETTSTORFER,
STODDART, ARCHBUTT, MOORE, HUBL, ALLEN, and others :* —

Saponification Equi-

Percentage off KHO

valent, or No. of

Nature of Oil.

for Saponification,
or Ib. KHO for

Grammes of Oil or Fat
saponified by One

100 Ib. Fat.

Equivalent inGrammes

of any Alkali.

A. OLEINS —

Lard oil .

19.10 to 19.60

Olive oil .

19.10 to 19.60

Olive oil .

18.93 to 19.26

Almond oil (sweet) .
Arachis oil

19.47 to 19.61
19.13 to 19.66

- 285 to 296

Tea oil .

19-55

Sesame oil

1 9.00 to 19.24

Cotton-seed oil

19.10 to 19.66

B. RAPE OIL CLASS—

Colza and rape oils .

17.08 to 17.90

Rape oil .
Mustard-seed oil

17.02 to 17.64
1 7.40 to 17.50

J- 313 to 330

Cabbage-seed oil

17.52

)

C. VEGETABLE DRYING

OILS—

Linseed oil

18.74 to 19.52

Poppy-seed oil

19.28 to 19.46

Hemp-seed oil .

19.31

286 to 300

Walnut oil

19.60

Niger-seed oil .

18.90 to 19.10

D. MARINE OLEINS —

Cod-liver oil .

18.51 to 21.32

Menhaden oil .

19.20

Pilchard oil

1 8.60 to 18.75

Seal oil .

18.90 to 19.60

- 250 to 303

Southern whale oil .

1931

Northern whale oil .

18.85 to 22.44

Porpoise oil

21.60 to 21.88

E. BUTTER CLASS —

Butter fat

22.15 to 23.24

241 to 253

Cocoa-nut oil .
Palm-nut oil .

24.62 to 26.84

22.00 tO 24.76

j 209 to 255

* ALLEN, " The Analyst," 1886, p. 146.

f These numbers x .5535 = percentage of soda (Na2O — 100 per
cent.), or Ib. of soda required for 100 Ib. of any of the fatty bodies.

SOAPS.

SAPONIFIGATION EQUIVALENTS — (continued}.

Nature of Oil.

Percentage of* KHO
for Saponification,
or Ib. KHO for
100 Ib. Fat.

Saponification Equi-
valent, or No. of
Grammes of Oil or Fat
saponified by One
Equivalent inGrammes
of any Alkali.

F. STEARINS, &c.—

Lard . . . j 19.201019.65

Tallow .

19.32 to 19.80

Dripping .

19.65 to 19.70

Butterine . . 19.35 to 19.65
Goose fat . . | 19.26

- 277 to 294

Bone fat . . . 19.091019.71

Palm oil . . . 19.63 to 20.25

Cacao butter . . j 19.98

G. FLUID WAXES—

Sperm oil

12.34 to 14.74

38010454

Bottle-nose oil

12.30 to 13.40

419 to 456

H. SOLID WAXES —

Spermaceti

12.73 to 13.04

43210441

Bees' -wax

9.20 to 9.70

Carnaiiba wax .

7. 90 to 8.51

Chinese wax .

6.50

I. UNCLASSED —

Shark-liver oil .

14.00 to 19.76

284 to 400

Wool fat (suint)

17.00

330

Lanolin .

9.83

570-9

Olive -kernel oil

18.85

298

Castor oil

17.60 to 18.15

30910319

Japanese-wood oil .

21.10

266

Japan wax

21.01 tO 22.25

25210 267

Myrtle wax

20.57 to 21.17

265 to 273

Blown-rape oil

19.80 to 20.40

275 to 284

Colophony

17.00 to 19.30

290 to 330

In the case of the glycerides, the saponification equivalent
is one-third of the molecular weight, but in case of mon-
atomic ethers, like those which essentially constitute sperm
oil and bees'-wax, the saponifieation equivalent is identical
with the molecular weight.

* See note f on p. 57.

CHAPTER V.

APPARATUS AND ARRANGEMENT
OP THE FACTORY.

APPARATUS.

THE apparatus of a soap factory is of a simple kind, and
may be arranged under the following heads : — •

i°. The lye tanks, for the alkalies.

2°. The pans, for effecting the combination between alkali
and fat.

3°. Various appliances for ivorking the product into com-
mercial forms.

i°. Lye Tanks, or Vats. — When the alkalies are caus-
ticized at the factory, the operation is performed in cast- or
wrought-iron tanks, 6 or 7 feet broad, and 4 or 5 feet in
depth, either furnished with a perforated false bottom, or
having a coarse piece of matting placed over the plug-hole.
From these tanks the lyes, of various strengths, are con-
veyed to the reservoirs. These may be, for convenience,
placed at one end of the soap-pan series, and at a some-
what higher level, so that the lyes may be readily run, by
means of a shoot, into the boilers, as required, or as N N N,
Fig. 22, p. 78, or B B B, Fig. 23, p. 80.

If the alkalies are obtained by the soap-maker in the
caustic state, their solution may be made in cast-iron or
sheet-iron kettles.

For the finer qualities of soap, especially toilet soaps, for

60 SOAPS.

which it is necessary to have a perfectly clear and colour-
less lye, it is advisable to have the vat or tank lined with
lead.*

2°. The Pans. — In these the combination between the
alkali and the fat is effected. They are variously termed
pans, coppers, caldrons, kettles, or boilers, and they differ
somewhat in construction, according to the process of soap-
making adopted. Speaking generally, large coppers offer
advantages over small ones in economy of labour, fuel, and
lye. It will be convenient to consider the construction of
the pans under the heads of the particular processes for
which they are suitable. The chief methods followed may
be classified thus : —

1. The ordinary 2)rocess (large-boiler process) : the open
boiling of an indefinite, i.e., not exactly proportioned, mix-
ture of fat and alkali.

2. Processes requiring the mixture of fat and alkali in
calculated proportions : —

a. The cold process (little-pan 'process).

b. Boiling under pressure.

c. Open boiling.

d. Free-acid process.

i. Open Boiling.

The pans are made either of cast or wrought iron — in
.small factories, often of cast iron, either in one piece, or in
plates united together by iron cement ; in larger factories,
more frequently of wrought-iron plates riveted together.
They are usually made with a flange at the rim, and above
this rim is fixed the curb, which is often made of wood, well
hooped with iron rings. Their capacity varies according to
the quantity of soap to be made at each operation : some-

* DUSSAUOE.

APPARATUS OF THE FACTORY. 6i<

times 15 feet deep and 15 feet in diameter, and capable of
turning out 25 to 30 tons at one boiling. It Las been
ascertained* that for every 100 Ib. of fatty matter a
capacity of 37 J gallons is required. Hence —

1000 Ib. fat require a copper of 375 gallons capacity
2000 ,, „ „ 750 ,,

3000 „ „ „ 1000-1125 ,,

In some large American factories the coppers extend through
several storeys of the building.

The heating may be accomplished either by fire or by
steam. In either case the pans are set in brickwork, and
so built round, when fire is used, that the fire shall not
play upon the sides, but only on the convexity of the
lower part of the boiler ; but, even after every attention has
been given to the construction of the arrangement on the
most scientific principles, there is an enormous waste of
fuel.

Heating by steam may be effected either by passing the
steam directly into the pan by steam-pipes terminating in
a perforated coil resting on the bottom of the pan (open, or
ivet method) ; or (a) by a closed coil, or (b) by means of a
steam-jacket (close, or dry method). If the steam is dis-
charged directly into the mass of soap, as in the open method,
some disadvantage is experienced through the weakening of
the lye by the condensation of the steam, and, on this
account, the use of more concentrated lyes is rendered
necessary. The arrangement found to work best is to send
the steam through a flat, closed worm about 3 or 4 inches
above the bottom of the pan. In this way a pan holding
1000 Ib. may be boiled in half an hour, while to do the
same by means of a fire would take from three to four hours.
Besides, a single steam boiler and one furnace will thus heat

* DrssAucE, " Treatise on the Manufacture of Soap," p. 344.

SOAPS.

several pans at once, and there is no danger of the soap
burning. Steam, therefore, affords economy of fuel, labour,
and time, and the boiling can be more readily, at any time,
controlled. Superheated steam is still more rapid in its
operation, and cheaper than ordinary steam.*

The lids of the pans, made either of wood or iron, are
arranged so that they may be put down, or taken off, by
means of a chain and pulley. The soap is removed either
by pumps or by ladling, and the lyes either by pumping or
by a pipe fixed to the bottom of the copper.

FIG. 6.

Fig. 6 represents a boiler arranged for heating by the
direct heat of a fire.

Fig. 7 is a representation of the arrangement designed
by CAMPBELL MORFIT for employing steam heat, and known
as Morfitri steam series.

In this figure three caldrons, A A A, are shown. In
large factories this is a convenient number, though more
are often used, but, in a small work, one will answer, though
there will always be a loss of time in cleaning it when the
charge has to be changed from yellow to white soap. The

* DUSSAUCE, " Treatise on the Manufacture of Soap," p. 350.

APPARATUS OF THE FACTORY. 63

SOAPS.

feeder, G, is attached to the boiler, w, which is generally
fitted against the wall, immediately above the caldrons.
The cook i is for the withdrawal of the spent lyes. The
pipe, L, called the blow-pipe, serves to communicate, when
necessary, additional heat to the contents of the pan, and is
also useful to stir up the mass occasionally, an operation
more readily accomplished in this way than by a crutch in the
hands of a workman. Steam is let on or off by the cock H.
Waste steam passes off through x. The current of steam
from the boiler may be regulated by the cock P.

2. Processes requiring Definite Proportions of
Alkali and Fat.

a. Cold process. — The apparatus required for this opera-
tion, according to HAWES, who invented it, may be an
ordinary caldron (Fig. 8) with the addition of a machine to

Fio. 8.

produce the intimate admixture and minute division of the
tallow; or a cylinder, as represented in Fig. 9, may be used.

b. Boiling under pressure. — For boiling under pressure,
DUNN'S apparatus, represented in Fig. 10, may be employed.

The boiler should be furnished with a man-hole, A, a
safety-valve, B, a thermometer fixed in a mercury chamber, C,

APPARATUS OF THE FACTORY. 65

and all the ordinary appendages of such an apparatus.
D is the feed-pipe, and E the discharge-cock. When in
use, the valve is weighted till the temperature in the boiler

FIG. 10.

rises to 310° F., and the boiling is complete in about an
hour after that temperature is reached.

c. Open boiling. — The ordinary open pans already de-
scribed are suitable for preparing the soaps which fall under
this head.

d. Free-acid process. — This is also called Morfit's process.
The boiler is made of wrought iron, is steam-jacketed, and
is fitted with a wrought-iron stirrer for thoroughly mixing
the ingredients. Fig. 1 1 is a representation of the steam-
jacket pan designed by MORFIT.

A is the interior of the kettle, surrounded by brickwork ;
B is the outer cast-iron caldron, which should fit the inner

66 SOAPS.

kettle tightly so as to prevent any escape of steam ; D is
the steam-pipe from the boiler, fitted with a cock by which
steam may be let on or off; C is the discharge-pipe for con-

FIG. ii.

densed vapour — the cock in this pipe may be left slightly
open so as to form a safety-valve ; E is the discharge-pipe
of the kettle.

A pump may be conveniently employed for taking off or
removing soap, when required, from one pan to another, or
for introducing either hot or cold lye, or strengthening
change lye. A very serviceable description of pump is made
by Hersey Bros., of South Boston, Mass., and is represented
in Fig. 12 (a, bj and c). a represents the pump complete.
When the pump is rotated in the direction of the arrow,
the outlet marked s is the suction ; when rotated in the
opposite direction, the opposite outlet becomes the suction,
and thus, by giving a few revolutions by hand in this
direction, the discharge-pipes may be emptied of their con-
tents, b is a view of the interior of the pump when the
cover is taken off; when turned in the direction of the
arrow, the blade F sweeps round, drawing the fluid in at i,

APPARATUS OF THE FACTORY. 67

and forcing it out at H, the contents of the pump being
twice emptied at each revolution. The fluid is prevented
from passing from one side to the other by the contact of
the cone with the cover, c shows the cone and blade, and
forms the entire working part of the pump. No valve is

FIG. 12.

used, and the operation of the pump is consequently little
liable to any derangement.

The pump may be set up in any convenient position adja-
cent to the pan, not more than 10 feet above its bottom, and
•connected to it by means of a 2|-inch iron pipe, tapped
through the iron plate at a distance of about 2 feet above
the worm, or coil. Several pans may be connected with the

F 2

SOAPS.

pump by iron pipes, with valves placed upon them on the
outside of the kettle, so that any one of them may be
pumped off and framed without disturbing the others. In-
side the pan the pipe has a suitable swing- joint so arranged
that it can be raised or lowered at pleasure.

3. Appliances for Finishing the Soap.

Prames. — The frames, which were formerly made only of
wood, are now constructed of iron, commonly cast iron, and
the wooden ones are chiefly used for mottled soaps, which

FIG. 13.

require slower cooling than other descriptions. When soap
was subject to duty, the dimensions of the frames were fixed
by law, and were required to be exactly 15 inches by 45
inches inside, and not less than 45 inches deep. These
dimensions are generally still retained in England, and

APPARATUS OF THE FACTORY. 69-

hence an English bar of freshly made hard soap measures
45 inches in length.

The wooden frame is made up of a number of separate
sections, piled upon each other, and fitting closely together.
Each section, having the internal measurement just men-
tioned, is about 9 inches in depth, and is constructed of wood,
:about 2 to 3 inches in thickness, lined with thin sheet-iron.
These are frequently piled upon one another to the height
of more than 20 feet. The bottom of the frame may be of
wood, or brick, and furnished with a well to receive the
drainings. When the soap has become solid, the frames
.are removed one by one, and the block of soap remains
ready for division into slabs.

Fio. 14.

Outside view of crutching machine.

70 SOAPS.

Iron frames are now extensively used. Fig. 13 is a re-
presentation of WHITAKER'S patent frame,* much used by
American firms. It consists of two sides of plate-iron,
flanged at their upper edges, and strengthened by ribs of
corrugated plate-iron, riveted to the outer surface, and run-
ning in the direction of the length of the frame. These ribs
are intended to prevent the budding or twisting of the side-

FIG. 15.

Working part of crutching machine.

plates. The trouble and expense of the ordinary stays and
supports are thus avoided, as the frame is self-sustaining..
The sides are connected by ends made of 2 -inch plank,
secured by clamps. The frame is very light, and easily

* Made by Horsey Bros.

APPARATUS OF THE FACTORY. 71

worked. The soap cools sufficiently to strip in twenty -four
hours in cold, and in forty-eight hours in warm, weather.

Crutching. — For stirring the soap-paste in the pans or
frames, an instrument called a crutch is used, consisting
simply of a board, to which a long wooden handle is
Fio. 1 6.

Jacket view of Clutching machine.

attached. For mixing various ingredients with soaps,
several forms of steam-crutching machines are employed.
]?igs. 14, 15, 1 6 are representations of a form patented by
STRUNZ (May 13, 1873, and April 23, 1878), and largely
employed in the United States. It crutches soap completely
within three minutes, and turns out an article of great
smoothness.

SOAPS.

Cutting and Barring. — The blocks of soap when re-
moved from the frames are marked off on the sides by
means of a scribe, or dentier. This consists of a stick of
hard wood, in which are fixed iron teeth. The distance of
the teeth from each other is arranged according to the
desired dimensions of the bars. The workman then, by
means of a brass or steel wire directed in the track of
the scribe-marks, divides the mass into slabs, which are
afterwards subdivided into bars.
FIG. 17.

The operation of barring may be rapidly accomplished by
machinery. Fig. 17 is an illustration of a soap-cutting
machine much used in this country.* It consists of a fixed
frame of woodwork, A A, and a movable lever-frame, B B,
attached to A A by the centre-pin, c. The frames are
wide enough to receive a slab of soap 45 inches long by
1 5 inches wide. This is placed in an inclined position, as

* RICHARDSON and WATTS, " Technology," vol. i. pt. iii. p. 664.

APPARATUS OF THE FACTORY.

shown by the dotted lines, resting on the bar, D, of the fixed
frame, and against a number of wires forming part of the
movable frame. "When the lever, G, is pressed down, the

wires pass through the slab of soap, dividing this into regular
bars, and when the handle is again raised up to the position

74 SOAPS.

shown in the figure, the bars of soap are found on the-
table, F, ready to be removed.

Fig. 1 8 is an illustration of RALSTON'S champion soap-
slabber, made by Hersey Bros., which is considered as
effective as it is simple, and is little liable to get out of
order.

Fig. 19 exhibits an arrangement, by the same makers,
by means of which the three operations of cutting, stamping,
and spreading may be carried out. The frame of soap is
cut into slabs either by the slabbing machine, of which
Fig. 1 8 is an illustration, or else by the old way of slabbing
by hand. In either case the slabs are taken one by one and
placed on the cutting-table, shown on the right-hand side of
Fig. 19. They are forced against a set of wires, and are
thereby divided into bars by turning the handle seen on
the right-hand side of the machine. They are afterwards
pushed against the wires shown on the left-hand side of the
machine, in a direction at right angles to the former move-
ment, and are thus divided into cakes, the size of which is
regulated by the distance apart of the wires.

The stamping attachment consists of a framework, which
is seen in the central portion of the machine, and which, by
suitable means, is brought down at regular intervals as the
soap passes through, so as to stamp upon each cake some name
or simple device. It is intended to be used in cases where
the soap is to be put on the market without being pressed.

The spreading attachment consists of a series of wooden
blocks of such size that, when the soap has passed through
the second set of wires, each cake rests upon one of the blocks.
These blocks are attached to strips of webbing in such a
manner that, when the strips are pulled tight, there is a
slight interval between the blocks. To receive the soap, the
blocks are pushed close together.

The racks for soap are laid so that the strips of which

APPARATUS OF THE FACTORY.

they are formed lie in intervals left between the rows of
blocks, and, after the soap has been pushed on the blocks by

the action of the cutting portion of the table, a slight puU
on the ends of the webbing separates the cakes, so that the
racks can be lifted and placed for drying, with the cakes of

ARRANGEMENT OF THE FACTORY. 77

soap in the best position for that purpose. The treadle,
shown on the lower portion of the spreading attachment, is
intended to lift each alternate block slightly before they are
pulled apart, so that the cakes of soap will separate more
readily.

Stamping. — The name of the maker, or the description
of the soap, &c., may be put on by means of a stereotype
plate and a mallet, or by a stamping machine, such as
Pigs. 20, 27, 28, 29. By the HERSEY steam press (Fig. 20)
a boy can turn out from 1800 to 2000 cakes per hour; a
gentle pressure of the foot upon the treadle fills the
cylinder with steam, causing the die to descend with
great rapidity and power upon the cake, and the instan-
taneous return of the lever raises it out of the die-box
ready for removal. The cakes may vary in weight from a
few ounces up to the largest sizes.

ARRANGEMENT OF THE FACTORY.

The following plans for a soap factory, which have proved
convenient in actual working, are outlines of those given by
DUSSAUCE and CRISTIANI :* —

The whole building is of an oblong or square form, divided
into three compartments.

i. The boiling-house, containing the kettles, frames, and
lye-vats, is most conveniently placed in the centre of the
factory and arranged round the large chimney. For a large
business, two large boiling -pans answer in most cases, while
two- other pans may be reserved for making the lyes. If
the kettles are to be heated by open fire, or by superheated
steam, the furnace is usually in the basement, while the rim

* DUSSAUCE, " Treatise on the Manufacture of Soap," pp. 382-388 ;
CRIBTIANI, " Technology of Soap and Candles," pp. 197-217.

78 SOAPS.

of the kettle is extended above the first floor, at a height
sufficient to facilitate the stirring.

The lye-tanks are best made of cast iron, and are fre-
quently inserted in the ground for the sake of economiz-
ing space. They must be well covered — best with cast-iron
Fio. 21.

lids. But the most "convenient arrangement is to have the
tanks in an elevated position, so that the lyes can be drawn
off.

2. Store-rooms. — Adjoining the boiling-house, on one
side, should be a warm store-room for the alkalies, and a
second room, as cool as possible, for the fatty matters.
FIG. 22.

ARRANGEMENT OF THE FACTORY. 79

3. On the opposite side of the boiling-house may be the
barring or cutting room and the drying and packing rooms.

Description of Fig. 21 (pans heated by open fire) : —

A A, Factory building.

B B, Kettles, c c, Fireplace. D D, Grate. E, General chim-
ney. P F, Ash-pit. G G, Cisterns for waste lye. H H H,
Vessels for oils and fats. / /, Cellars. L L L, Lixiviating
vessels, situated above caustic lye-vats. M M (on right of
illustration), Soap frames ; the upper part should be lower
than the edge of the kettle, so that, after boiling, the soap
may, by a shoot, be readily run into them. M M (on left of
illustration), Store-rooms. N, Apparatus for poiudering crude
soda.

Description of Fig. 22 (pans heated by steam): —

A, Boiler. B, Fire-grate. c, Chimney. D, Dome from
which steam is discharged through the pipe, F F, and the
flat coil, E E, at the bottom of the kettle. F F, Kettles.
G G, Waste-pipes. H H, Spent-lye pipes. 1 1, Spent-lye cis-
terns. M M, Foundation of kettles. N N, Sheet-iron caustic-
lye, vats, o o, Soap-frames. P, Barring-table. Q, Drying-
room. R, Soap-moulding machine.

The arrangement of a small factory illustrated in Fig. 23
is one that has been found efficient in its results and econo-
mical in its working. It may be thus briefly described : —

A A are soap-pans, consisting of a wrought-iron curb,
b being the cast-iron bottom. These pans, one of which
only is shown in section, are set in brickwork, bound round
with wrought-iron tie-bands, c is the cock for drawing off
the lyas or spent alkali.

d d the close steam-heating worms, or pipes, connected to
the steam and waste mains, G and H.

e e are the open free steam-boiling worms.

//are the tie-bands for securing the brickwork round
the boiler.

SOAPS.

Both the pans have covers the same as shown on the pan
not in section.

Fm. 23.

B B B are the cast-iron lye or alkali vats, having false
bottoms, and being fitted with water-supply.

C C G are the cast-iron pans for receiving the lyes or
alkali solution from the vats, B B B. The lyes are taken
from these pans by means of a pump, through a trough, to
the soap-pans, A A.

E E E E are the frames in which the soap is cooled, the
side and end plates of which are taken off.

F F are steam- jacketed pans for making toilet soap.
They are fitted with free steam-boiling worms and all neces-
sary connections, and are placed on a bench as indicated.

G is the main steam-pipe from the boiler.

II is the main waste steam-pipe.

CHAPTER VI.
CLASSIFICATION OP PROCESSES.

DR. W. LANT CARPENTER'S classification is as follows:* —

a. Soaps produced by the direct union of fatty acids and
caustic alkali, or by the decomposition of carbonated alkali
by fatty acids.

b. Soaps produced by the action of the precise quantity
of alkali necessary for saponification upon a neutral fat,
without the separation of any waste liquor, the glycerin
being retained in the soap. This class includes (i) soaps
made by the cold process ; (2) soaps made under pressure.

c. Soaps produced by the ordinary methods of boiling in
open vessels, working with indefinite quantities of alkaline
lyes, the processes being controlled by the experience of the
operator. These are again subdivided into (i) soft soaps, in
which the glycerin is retained, potash being the base;

(2) the so-called hydrated soaps, in which the glycerin is
retained, and of which marine soap may be taken as a type ;

(3) hard soaps, with soda for the base, in which the glycerin
is eliminated, comprising three kinds — curd, mottled, and
yellow soaps.

Dr. C. R. A. WRIGHT f classifies the various processes for
the production of soap as follows : —

* SPON'S "Encyclopaedia," v. 1770.
f Cantor Lectures, " Journ. Soc. Arts," May 1885.

82 SOAPS.

Group I. — Fatty, or resinous, acids in the free state
directly neutralized with alkalies (carbonated or caustic).
Resulting soap devoid of glycerin.

Group II. — Saponification of fatty glycerides by alkalies,
with retention of glycerin intermixed with the soap. In
this group are the processes for making (a) soft soaps and
marine soaps by open boiling; (b) soaps made by boiling
under pressure ; and (c) cold-process soaps.

Group III. — Saponification of fatty glycerides by alkalies,
with separation of glycerin.

Group IV. — Processes consisting of combinations of the
foregoing.

It will be seen from a consideration of the above that the
methods may be arranged under three main heads — viz.,
open boiling, boiling under pressure, and the cold process.

i. General Process.

The general method of preparation is the same for all
the hard soaps, but there are variations in the details, more
especially in the later stages. The following is an outline
of the general method : —

i°. Saponification, Pasting, or Killing the Goods. — Usually
the whole of the fat to be saponified is introduced into the
boiler, and at the same time, for every ton, from 150 to
200 gallons of caustic lye, of sp. gr. 1.050 to 1.085 (10° to
17° Tw.), are added, and the whole is gently heated to
ebullition. Lye stronger than sp. gr. 1.085 would, at this
stage, hinder Saponification. After boiling for an hour and
a half or two hours, a viscid emulsion, capable of being
drawn out into threads, or ribbons, is produced.

2°. Separation, Cutting the Pan, or Salting. — To separate
the imperfect soap produced, and to allow the spent lye,
containing the glycerin, to be withdrawn, a sufficient

CLASSIFICATION OF PROCESSES. 83

quantity of common salt is added, and this, dissolving
in the liquid, causes the soap, which is insoluble in the
saline solution, to rise to the surface, combined with a
definite proportion of water. Thus separated, the soap is
called grain soap. The spent lyes should contain no caustic
soda, and no fat should be thrown up on adding to them a
mineral acid.

3°. Completion of Saponification or " Finishing" — This
part of the operation follows the removal of the waste lye,
by pumping or drawing off. It consists in boiling up the
granulated soap with fresh, stronger lyes, called strengthen-
ing lyes, to complete the soap, and to bring it into what is
called the close state.

If curd soap is to be prepared, it is allowed to stand a
while, that the lyes may subside, and then the operation
is continued as in 5°.

If the grain soap contain impurities, such as iron soap,
iron sulphide, &c., and if the quantity of water be not in
excess after cooling in the frames, a marbled or mottled
appearance results.

4°. Fitting. — The unrefined grain soap is apt to contain
a proportion of lye entangled in it. To separate this, the
curd is melted,, with the addition of water or weak lye, and
foiled, so as again to produce a homogeneous compound.
The mixture is allowed to stand for a considerable time —
about two days — when a separation takes place into three
layers, and the soap, which forms the middle layer, is then
treated as in 5°.

5°. Cooling and " Cleansing." — When the soap has re-
mained in the pan a sufficient time to become partially cool,
it is ladled out in buckets, or pails, or by other means con-
veyed to the frames to solidify.

Curd soap has then a rough, granulated texture, and is
extremely hard, containing only about 20 per cent, of water.

G 2

84 SOAPS.

A properly fated soap will have a feathery texture, and
contain about 30 per cent, of water.

6°. Barring and Drying. — The soap having become cold,
the frames are removed, and a compact mass of soap, the
size of the frames, remains. This is marked round by the
iron-toothed scribe or dentier, the teeth of which are near
or distant from each other according to the size of the
blocks desired. The mass is then cut in the places so marked
into slabs, and these slabs are subdivided into bars. These
bars are then removed to the drying-room, and piled upon
one another cross-ways, interstices being left for the circula-
tion of air to facilitate the drying.

MORFIT thus describes the general method pursued in the
United States: — 1°. "The strength of the lye employed
varies as the fat to be saponified is richer in olein or in solid
constituents. The operation is commenced by pouring the
lye into the copper to a third of its capacity. This is then
heated to ebullition, and the oil is now run in. The reaction
is such that a magma is immediately formed. The proper
formation of this magma is considered to be the most
delicate and important part of the whole process, and, if
badly managed, a much greater quantity of lye is required
to form the same weight of soap than would otherwise b&
necessary. After the addition of the fat, the heat is-
decreased by opening the doors of the furnace, and, when
the mixture of fat and lye is complete, if necessary a further
quantity of weak lye is added gradually, and with constant
stirring during the addition so as to insure thorough con-
tact. The mass should remain homogeneous \ the oil should
neither rise to the surface nor descend to the bottom.

" If oil should present itself, it is then necessary to add
more strong or weak lye, according to the capacity of the
caldron. On the other hand, if the lye is in excess, a further
quantity of oil must be added, always stirring briskly upon

CLASSIFICA TION OF PROCESSES. 85

any addition of new material. The operation requires from
eighteen to twenty-four hours for completion, but it may
be greatly accelerated by throwing in the scrapings or waste
of soap already made."

" An excess of soda is recognized by the liquidity and
transparency of the paste. When oil is in excess, it rises
to the surface. An excessive proportion of common salt in
the soda also more or less interferes with the proper for-
mation of the magma, and, if the proportion is very con-
siderable, the use of soap scraps is indispensable."

2°. " The next step in the process is the removal of the
large quantity of water which was required for the complete
saponificatioru This is effected by the addition of lye con-
taining common salt, and by afterwards boiling the mixture
for from fifteen to twenty hours, with constant stirring.
When the mass opens in different places, the separation is
complete. The fire is then withdrawn, and the whole is
allowed three or four hours' repose, after which the settled
waste, or spent, lye is drawn off. A further quantity of
lye, charged with common salt, is now added, and the mix-
ture is gently boiled, care being taken to remove from the
sides of the caldron any adhering soap, so that all portions
may come into contact with the lye. The mass now acquires
more consistence, and, after some hours' rest, the settled
waste is again withdrawn."

3°. "A fresh quantity of lye, of sp. gr. i.io (20° Tw.),
is now added, and the mixture again boiled, by which it
acquires still greater consistence. After about three hours'
further boiling, it is allowed to settle, and the spent lye
is again drawn off. This operation is again repeated, with
strong lye, constant stirring, and gentle ebullition, so that
the whole may form a homogeneous mass. At this stage
the soap begins to acquire firmness.

" The boiling with lye several times successively serves

86 SOAPS.

not only to complete the saponification, but to wash and
purify the soap. That it may be perfect, it is necessary to
repeat the operation four or five times. As soon as com-
plete, the heat should be withdrawn, and the mass allowed
to settle and become somewhat cool. It is then ready to
be conveyed to the frames."

2. Saponification under Pressure.

BENNETT and GIBBS, of Buffalo, N.Y., took out a patent
in 1865 for making soaps by agitation under pressure.
This method consists in agitating in a closed vessel, or boiler,
fitted with a revolving shaft, or stirrer, the fatty matters
with caustic or carbonated alkalies in solution in water
while under heat and pressure, in such a manner as to
cause a thorough mixing of the fats with the alkaline
solution, and the production of a rapid combination of the
fatty acids with the base. The pressure is 220 to 280 Ib..
per square inch, at the temperature of 350° to 400° F.
(176.6° to 204.4° 0.). At first, if carbonated alkali be
used, it is necessary to allow some of the liberated carbonic
acid to escape, so as to avoid undue pressure. A batch of
soap may, in this way, be made in less than one hour.

The patentees used from 30 to 33 Ib. of sodium carbonate
at 48°, and 100 Ib. of water to each 100 Ib. of lard, tallow,.
or oil. The produce obtained is 200 Ib. of soap for every
100 Ib. of grease.

The following advantages are claimed for this method : —
(i°) Rapidity; (2°) Quality improved; (3°) Quantity in-
creased; (4°) Labour saved; (5°) Fuel saved; (6°) Cost
of materials saved; (7°) Completeness of saponification;.
(8°) Uniformity of results ; (9°) Incorporation of glyce-
rin ; (10°) Admissibility of alkaline salts, instead of caustic-
lye.

DUNN'S method (p. 103) is also available for preparing.

CLASSIFICA TION OF PROCESSES. 87

ordinary soaps under pressure. It differs from the pre-
ceding in the employment of caustic, instead of carbonated,
alkali, and of a lower pressure (20 to 65 Ib. per inch).

3. The "Cold" Process.

By this method the high degree of heat necessary in the
ordinary process is entirely dispensed with, and complete
saponification is effected at temperatures lower than the
ordinary boiling heat. The following is the description of
the system as given by WILLIAM HAWES, the inventor : —
Two tons and a half of tallow, or any given quantity, are
taken and melted at as low a temperature as possible, and
then mixed, by mechanical means, with the quantity of lye
required to completely saponify the fat. Ordinary soap-
boiler's lye is used, preference being given to that made
from the strongest and purest alkali. The saponification of
the tallow, or other fat, may be ascertained by its absorp-
tion or combination with the lye, care having been taken,
in the first instance, to use a sufficient quantity of the
lye. Twenty gallons of lye, of sp. gr. 1.125 (25° Tw.),
are required for every 100 Ib. of tallow, but the proportion
varies according to the nature of the fat or oil* employed.
An ordinary soap-pan may be used as the combining vessel,
with the addition of a stirrer to facilitate the admixture of
the tallow and the lye. Figs. 8 and 9 (p. 64) will convey an
idea of the apparatus. For the quantity of fat mentioned
above, if the cylinder is used, it should be about 6 feet in
diameter and 12 feet in length. When it has been charged
with fat, motion is communicated to the machinery, and the
lye is then gradually added. In a short time the ingre-
dients will be thoroughly mixed, but the agitation must be
continued for about three hours, or until saponification
appears to be complete. During the process there is a con-
siderable evolution of heat. After from one to four days.

88 SOAPS.

according to the quantity, it is hard enough for use. As
the value of the process chiefly depends upon the lowness of
the temperature at which the saponification is effected, it is
desirable to transfer the contents of the cylinder, as soon as
thickening occurs, to an ordinary soap-pan, where the opera-
tion may be finished, either by conversion into yellow soap
with the addition of rosin, or into mottled or white soap by
finishing lyes in the usual way.

The cold process is very suitable for the manufacture of
soap on a small scale, and in such case the mechanical stirrer
can be dispensed with.

The advantages obtained by this process are — economy
of cost and time, retention of the glycerin, and, when per-
fumes are introduced, the avoidance of loss which a high
temperature naturally causes.

The disadvantages are — the liability of the product to con-
tain an excess of alkali, and the necessity of having very
pure materials, because in no part of the operation is there
any opportunity of getting rid of objectionable impurities.
If the alkali contains too much chloride, it will be necessary
to add a proportion of cocoa-nut oil in order to effect the
saponification. It is also not uncommon to find, owing to
incomplete saponification, that the product contains both
unsaponified fat and free alkali.

"We shall consider the various commercial soaps produced
by these methods, or by modifications of them, in the
following order : —

Household, domestic, laundry, or plain soaps.

1. Curd, or white, soap.

2. Genuine mottled soaps.

3. Castile, Marseilles, Venetian, or olive-oil soaps —

white and genuine mottled.

4. Artificially mottled soaps — blue, grey, and red.

5. Yellow, or rosin, soap.

CLASS1FICA TION OF PROCESSES. 89

6. Cocoa-nut-oil, marine, or liydrated soaps.

7. Silicated soaps.

8. Sidphated soaps.

Toilet, or fancy, soaps.

Medicinal, or pharmaceutical, soaps.

Oleic-acid, or red-oil, soaps.

Soft soaps.

Industrial soaps.

CHAPTER VII.

HOUSEHOLD, DOMESTIC, OB LAUNDBY
SOAPS.

HAKD soaps are made with non-drying oils, or solid fats and
soda. Their hardness is in proportion to the amount of
stearic and palmitic acids which they contain. Soda soaps
made with drying oils, such as linseed, are pasty and easily
liquefied by a small quantity of water, and approach to the
character of soft soaps made with potash. The most im-
portant kinds of hard soaps arc those made chiefly with
tallow, as in England and other Northern countries, and
olive-oil^soaps, as made in Southern Europe.

i. Curd, or Wliite, Soap.

A. ENGLISH METHOD.* — The fatty materials used for
the production of hard soaps in this country are tallow,
lard, palm oil (well bleached), and cocoa-nut oil, or mixtures
of these in almost any proportion. The pan used is the
ordinary open boiler (pp. 62, 63, 66), heated either by fire
or by closed steam-pipes. From 10 to 14 cwt. of tallow are
required to produce i ton of soap.

i°. The pan having been charged with the fat, weak lye
of specific gravity about 1.040 is added (the proportions are

* Founded on GOSSAGE'S description — KICHAEDSON and WATTS,
«' Technology," vol. i. pt. iii. p. 680.

HOUSEHOLD SOAPS. 91

about 200 gallons of such lye to i ton of the fat), and
the whole is heated, by injection of steam, or otherwise.
If the process goes on properly, the fatty matters soon com-
bine with the lye, producing a uniform milky emulsion,
from which no watery particles separate on cooling. If
such an emulsion is not produced, water, or weaker lye, is
added, and the boiling is continued till the combination is
complete. At this stage, the application of the tongue
shows that the taste of the alkali has passed away, or, in
technical language, the lye is killed. Repeated additions of
stronger lyes are made, and the boiling is continued till the
presence of free alkali becomes evident to the tongue. It
is then necessary to introduce more fat, followed by stronger
lyes, but with care that, at this stage, the alkali shall not
be in excess.

2°. The imperfect soap is now separated by the addition
of common salt, and, after a few hours' subsidence, the
spent lyes are withdrawn from under it. This spent lye
contains a portion of the glycerin of the fat, together with
sodium sulphate (from the alkali used) and common salt.

3°. The next stage of the process consists in the*addition
of weak lye to the imperfect soap, and subsequent^boiling to
bring the contents of the pan into a state of homogeneous
mixture, called the close state, as distinguished from the
granulated condition in which the soap separated at the end
of the first operation.

Stronger lyes (of about sp. gr. 1.160) are now added till
the mixture has a strongly alkaline taste. Sufficient com-
mon salt is then thrown in to cause the separation of the
soap, and the mixture is boiled for several hours, so that
the whole of the fat may be combined with the alkali.*

* This point is well known to the experienced workman by the
consistence of the compound. If a little of the mass taken out on a

-92 SOAPS.

In this process, attention has to be specially given to the
separation of the alumino-ferruginous impurities of the lye,
which, if not removed, tend to discolour the soap. Their
removal is effected by boiling the soap several times with
fresh weak lye or water, applying gentle heat, covering the
caldron, and allowing time (one to two or three days, ac-
cording to the quantity of the materials) for the darker-
coloured soap, or nigre, to settle. The upper stratum of
white soap is afterwards ladled out into the cooling frames,
-curd soap being generally too thick to pump.

In England by far the greater quantity of curd soap
produced is made from tallow, or mutton suet, and soda
only. Soap thus made is, however, inconveniently hard
and difficult of solution. Hence, some manufacturers re-
place one-fourth of the tallow by as much lard, or olive oil,
obtaining thus a soap of superior quality, and less liable to
change by exposure. Lard has this advantage over olive
oil — that it does not detract from the whiteness of the soap.
The advantages gained by the use of lard and olive oil with
tallow are thus summed up by MUSPRATT :* — " The soap
remains unaltered for a longer period ; it does not emit the
-disagreeable odour of tallow ; and the saponification is more
perfect, as the excess of olein in the lard, or oil, compen-
sates for the large amount of stearin in the tallow, thus
inducing a more ready and perfect union of the alkali and
fatty acids."

English curd soap is much used in Yorkshire by cloth

trowel is squeezed between the finger and thumb, it will still have a
greasy feeling if not thoroughly finished ; but if the saponification
is complete, it will readily separate from the skin in hard scales.
Or a portion may be decomposed by an acid, and, if the saponifica-
Aion is complete, the separated grease is wholly soluble in boiling
.spirits of wine, but not otherwise.
* " Chemistry/' ii. 879.

HOUSEHOLD SOAPS. 93

manufacturers, and at Nottingham in the bleaching of lace
and stockings.

B. GERMAN METHODS.* — (a) The old method of preparing
hard soap formerly practised in Germany is of great interest,
historically and chemically, and a short description of it may
therefore find place here.

i°. The crude tallow is saponified with potash lye pre-
pared from potashes causticized by lime in the usual manner.
The first lye has a strength of 20° B. Soon after the boiling
has commenced, an emulsion is formed, and, on continued
ebullition, the mass becomes clear, having the appearance of
a thick syrup, indicating that the whole of the fat has
entered into combination with the potash. Turbidity may
be due either to excess or deficiency of potash, or to the
presence of lime. On treatment of a few drops of the
mixture with pure rain-water, a continuance of the milkiness
indicates unsaponified fat or the presence of lime. If the
latter is the cause, it is removed by the addition of a car-
bonated alkali; when there is unsaponified fat, more lye
must be added and the boiling continued. The milkiness
due to excess of alkali disappears on addition of water.

2°. "When the clear solution will flow from the spatula in
an unbroken stream of the consistence of treacle, and will
solidify to a thick jelly when placed on a cold stone, the
product is ready for the salting process. This consists in
throwing salt into the pan and boiling up with the solution
of soap. " Double decomposition " takes place analogous to
that ensuing between silver nitrate and sodium chloride (see
example (e) (2), p. 51), thus: —

{•»§£.} +

Potash soap Soda soap

* RICHAUDSON and WATTS, " Technology," vol. i. pt. iii. p. 674.

r UNIVERSITY 1

94 SOAPS.

This reaction, in conjunction with the excess of common
salt, causes the separation of the soda soap and the forma-
tion of the under-lye. The soap, insoluble in the brine,
coagulates into a whitish mass of small flocks. After resting
for some time, the soap is scooped out into the cooling-
frame. The soap is obtained quite clean, even from very
impure materials, being washed by the salting process. The
impurities from the salts in the ash employed, and from
the action of the lye on the membranous parts of the crude
tallow, are all found in the under-lye.

When all the soap has been taken out, the lye is removed,
and the soap afterwards replaced in the clean pan, with an
addition of fresh weak lye. The mass is boiled, and a clear
solution, as in the first boiling, is obtained, containing
chiefly soda soap, but with an admixture of potash soap
from the fresh lye. Salt is again added, and the boiling
continued. The heat is then removed, the contents of the
pan allowed to rest, the soap scooped out again, and the
under-lye emptied out.

After this, if crude tallow has been used, about three or
four more boilings must be made before the soap is com-
pletely saturated with alkali. Less salt is required at every
fresh boiling, because there is gradually less potash soap to
be decomposed.

A less number of boilings will be sufficient if purer tallow
is employed.

3°. The mass is then boiled clear, and if the soap appears
satisfactory, the fire is withdrawn, and the product is
skimmed off and transferred to the mould.

100 Ib. of tallow will produce from 150 to 155 Ib. of curd
soap, weighed as soon as cut.

Dr. C. K. A. WRIGHT has pointed out * that, in all pro-

* Cantor Lectures, " Journ. Soc. Arts," May 1885.

HOUSEHOLD SOAPS. 95

bability, hard soaps were first manufactured in this way,
the use of wood ashes and fatty matters for making potash
soaps of a crude character being the earliest traceable kind
of soap-making, and that this mutual decomposition is avail-
able for the manufacture of hard soda soaps under circum-
stances when caustic soda is less readily obtainable than
potashes — e.g., where wood ashes are available in districts
a long way from commercial centres where soda ash and
caustic soda can be bought.

This old method, brought to great perfection by long
experience, enabled the manufacturer to prepare an excel-
lent soap, but the increasing price of potash and the
cheapening of soda have caused it to be nearly abandoned
for the modern method of saponification by soda alone.

(6) Modern German Method* — The boiling is conducted
as follows : — The pan is charged with 190 gallons of soda-
lye of 13° B., and 2000 Ib. of the best melted suet. The
mixture is gently boiled for two hours after it has be-
come milky; then the heat is withdrawn, two hours' repose
is allowed, and the lye is run off. Boiling with fresh lye
follows, and when the soap, on pressure between the fingers,
forms clean solid scales, a few buckets of lye are thrown in
to cool it, and again drawn off after settling for a while.
The soap is again boiled up with 9 or 10 gallons of fresh
lye, and, when fusion is complete, a trial of the paste is
made with the spatula. If it runs from the lye, water is
added ; if it does not run, it must be boiled a little longer,
adding a bucket of water containing a third of its weight
of common salt, in order to effect the separation of the
soap. When this separation appears to be complete, after
settling for about an hour, the liquid, which contains the
greater part of the lye remaining from the first boiling,

* RICHARDSON and WATTS, " Technology," vol. i. pt. iii. p. 678.

96 SOAPS.

generally of a deep bottle-green colour, is drawn off.
About eight buckets of water are now added, and the boil-
ing continued till the incorporation is complete. If, on exa-
mination, the soap runs from the water, more water must
be added, in small portions at a time, till the running ceases,
and the pasty mass, when shaken, trembles like a gela-
tinous compound. The operation is finished by well boil-
ing the contents of the pan, and, unless the soap has a
bluish tinge (in which case it should have another wash-
ing), the heat is then withdrawn, the pan covered up, and
the whole left at rest for a day or more. The soap is
then ladled into the frames.

2. Genuine Mottled Soap — English or London.

The cheaper fatty matters are usually employed for this
description of soap, such as bone-fat, kitchen-stuff, inferior
tallow, &c. Lyes prepared from crude sodas are preferred,
because the impurities which they contain materially help
in the formation of the strike, or mottled appearance.

The process, up to the third stage, is conducted in a manner
similar to that adopted for curd soap (p. 90). After this,
instead of allowing the total subsidence of the nigre, the
operator inserts a rake, breaking the paste in all directions,
and then, thrusting it downwards to the lye, he draws it
rapidly upwards so as to cause some of the lye to rise and
spread over the surface. As it descends through the viscid
mass, the dark-coloured nigre leaves veins or marks which,
in the cooled soap, remains as mottle. When ready for
cleansing into the moulds, the soap is in a gelatinous
condition, interspersed throughout with lye. To judge of
the proper condition for cleansing requires the experienced
care of a good soap-boiler. If iron frames are used, the ends
of the bars have often no marbling, owing to the too rapid
cooling of the parts in contact with the metal, and hence

HOUSEHOLD SOAPS. 97

some makers prefer to use wooden frames for mottled
soap.

3. Castile, Marseilles, Venetian, or Olive-oil Soap —
White and Mottled.

The process for the manufacture of this soap does not
differ greatly from that of other hard soaps. The fatty
material used is olive oil, often with the addition of poppy,
cotton-seed, or other seed oil, as the soap made from olive
oil alone is inconveniently hard. Of course only the cheaper
kinds of olive oil are employed, the most suitable being those
which contain the largest proportion of stearin, and which,
consequently, most readily solidify in the cold.

The operation may be described in four stages : —

i°. The preliminary boiling, or pasting (empatdge) ;

2°. Cutting the pan (relargage) ;

3°. Clear-boiling (coction) ; and, in the case of mottled
soaps,

4°. Mottling, or marbling (madrage).

i°. Pasting. — The lye, of 8° to 11° or 12° B. (the latter
when the oil is thin, the former when it contains more solid
matter) is either run into the boiler, or prepared therein
by mixing weak and strong lye till the desired strength is
reached. It is necessary to be particular about its strength,
because, if too strong, or if the quantity of lye be excessive,
the solution of the soap formed is hindered, and the first
action of the oil and alkali can only take place rapidly and
completely when the soap remains dissolved in the lye.
This lye should also be, for this stage, as free as possible
from common salt (soft lye) ; hence the purer kinds of soda
are taken for the first lye, and afterwards soda containing
sodium chloride (salted lye).

The oil is run in at once with stirring, when the lye has
reached the boiling point. An emulsion is soon produced,

98 SOAPS.

and any excess of oil or of lye is then noticed and treated in
the manner already described (pp. 84, 85, 91, 93). As soon
as the mass has become perfectly uniform, and has acquired
the consistence of soap, the heat is withdrawn, and the salt-
ing process begins.

2°. Cutting the Pan, or Salting. — This operation is per-
formed as detailed previously (pp. 82, 85, 91, 93), or by
the use of salted lye at 25° to 30° B. The solution of salt,
or the salted lye, is thoroughly mixed with the contents of
the boiler. The soap, insoluble in the salt solution, separates
in flocks from the excess of water, and by continued boiling,
it is at length brought to a granular or curd-like condition.
At this point the heat is removed, time is allowed for the
lye to deposit, and the liquor is afterwards drawn off.

3°. Clear-boiling, or Clarifying. — The lye now added
must be so strong that the soap will not dissolve in it. Its
strength is accordingly 18° to 20° B.,and about 10 percent,
of common salt is added. According to DUSSAUCE, it is
preferable to begin this part of the process with soft lyes
— that is, lyes free from salt. After boiling till the caustic
properties of the lye are lost, the liquor is drawn off and
replaced by a similar lye, and it may be necessary to repeat
the treatment with fresh lye several times, till the soap has
greater consistency, and the alkalinity of the lye remains
unaffected. This shows that the soap is completed, as it will
take up 110 more alkali. The mixture no longer boils
smoothly, but in jerks, and the curd, when pressed against
the palm of the hand, forms a firm and granular mass, which
does not adhere to the skin.

Up to this point the details of the process are nearly the
same for both white and mottled Castile soap.

If a white soap is to be produced, the impurities, such as
iron compounds, &c., must be separated by further treat-
ment as in °«.

HOUSEHOLD SOAPS. 99

3°a. Liquefying. — The last lyes having been drawn off,
the soap is again treated with weak lye, and heated gently,
so that the heavier, dark-coloured soap, or nigre, may sink
below the lighter mass of purer soap. After settling for a
sufficient time in the covered boiler, the upper stratum is
ladled off into the frames, and is sometimes, as an additional
precaution, poured into these through sieves, so as to keep
back casual impurities.

4°. Mottling. — If, instead of a white soap, the object is to
produce a mottled soap, impure soda, containing sulphides,
is preferred for the lye, and a quantity of ferrous sulphate
(green vitriol), about 8 oz. for each cwt. of oil, is added at
the end of the preliminary boiling. This is at once precipi-
tated, partly as iron oxide and sulphide, and partly as an
insoluble iron soap. In consequence of this addition, and
also from the presence of iron and sulphur in the lye, and
of ferruginous matters from the pan, the curd obtained at
the end of stage 3° has a uniform slate colour. If this were
allowed to remain, the effect would not be pleasing, but,
instead of directing his endeavours to exclude these impuri-
ties, as in the case of the white soap, the soap-maker con-
ducts the operation in such a way as to preserve and arrange
them, by diffusing the colour in veins, in order to give a
marbled, or mottled, appearance. When the proper con-
sistence of the soap has been attained, the mass is worked
about with rakes, so as to bring the lower and darker-
coloured parts of the curd to the top. When this has been
sufficiently done, the viscid soap is transferred to the frames,
where, in about a week or more, according to the quantity,
it cools down to mottled soap. By varying the proportion
of iron sulphate added, a tint is produced of a lighter or
darker hue. By exposure to the air, the iron gets oxidized
to the state of sesquioxide, and a reddish tint, called manteau
Isabette, is diffused over the bluish mottled mass.

H 2

ioo SOAPS.

It is thus apparent that in mottled soap the veins and
patches of heavy, insoluble, coloured compounds are present
because, by special manipulation, they have been intention-
ally prevented from subsiding, and by the conveyance of
the soap to the frames in so viscid a condition that the
downward trickling of the coloured impurities should pro-
ceed so slowly as only to intensify the desired appearance,
and not subside altogether. It is evident also that, if a soap
so prepared were thinned by admixture with water, the
impurities would more readily subside, and that the veining
or mottling would be greatly diminished or entirely pre-
vented. Hence, a genuine mottled soap cannot contain
more than 33 or 34 or, at mosfc, 36 per cent, of water.
Hence, also, as a mottled appearance was formerly a special
characteristic of " Castile " soap, and as this was essentially
a good soap, a mottled or marbled character came to be
regarded as a sign of excellence. So far was this belief
carried, that it used to be said there was no need to analyse
a marbled soap, as it must necessarily be genuine.* This,
however, is now by no means the case.

4. Artificially Mottled Soa2^s — Slue, Grey, and Red.

BLAKE and MAXWELL'S process may be used to produce
these soaps. Two soap-pans are required. In one of these
a known quantity of tallow, or bleached palm oil, or a mix-
ture of 80 per cent, of cocoa-nut oil, 14 per cent, of tallow,
and 6 per cent, of lard, is boiled with a quantity of soda
lyes, carefully calculated by means of the second table on
p. no, and the hydrated soap thus formed is transferred to
the other pan, in which a soft curd soap has been prepared
from fatty matters and lyes, as calculated from the first table

* KAMPEL'S " Method of Assaying Soaps," quoted in WATT'S "Art
of Soap-making," p. 209.

HOUSEHOLD SOAPS. 101

on p. no. The mottle is produced by adding to this soap,
when in a finished state, colouring matter to impart the
desired colour, and in about half an hour after the soaps
and colouring matter have been thoroughly incorporated,
the soap may be transferred to the frames. For the best
descriptions of mottled soaps, the weight of fatty matters
used to produce the hydrated soap amounts to from one-
fourth to one-half of the fat used to produce the soft curd.
For cheaper descriptions, the hydrated soap may be in-
•creased till the proportion of fat in the hydrated soap
amounts to from two-thirds to one and a half times the
weight of fat in the curd soap.

Another way is to prepare a " fitted " soap from the fatty
mixture containing cocoa-nut or palm-kernel oil in one
pan, and to remove it from the nigre to the second pan.
Here, for every 1000 Ib. of soap, are added 250 Ib. of
sodium silicate, and the whole is thoroughly incorporated
by boiling, until the experienced workman judges that the
proper condition for mottling has been attained. The
colouring matters mixed with water are then sprinkled
into the pan, and, after boiling for a few minutes, the
mixture is transferred to the frames.

The colouring matters are — for blue, artificial ultramarine,
5 to 10 Ib. per ton; for grey, manganese oxide, i to 3 Ib.
per ton ; and for red, vermilion.

5. Yellotv, or Rosin, Soap.

The distinctive yellow tint of this soap is due to the pre-
sence of a considerable quantity of rosin. Several methods
are followed in its preparation.

i°. The ingredients are common fat, or inferior tallow, or
bone-fat, or red oil, palm oil, and rosin. The proportion of
rosin in this mixture should not exceed one-third of the
fat ; if equal parts are used, the soap produced is soft and dark

102 SOAPS.

coloured. It is usual, in this country, to partially make-
the palm oil or tallow soap, and, when the saponifi cation is
nearly complete, to introduce, with the last charge of lye,
the coarsely powdered rosin. The contents of the copper are-
then well mixed together and boiled for some hours, generally
with open, or wet, steam, adding more lye whenever neces-
sary, to preserve an excess of alkali till the completion of the
saponification. This point is ascertained by cooling a portion
of the soap and noting whether it then has a proper con-
sistence and the proper grain, and whether it will wash
without leaving a film of rosin on the hands.

The lyes having been drawn off, the paste is next purified,
or fitted, by boiling up with weak lye (about 8° B.) in order
to facilitate the deposition of the impurities. After resting
for a while, the lye is again removed, and boiled once or
twice more with still weaker lye. After a long interval —
from a day or two to a week, according to the size of the
pan — there is a separation into three layers : a scum, OT/ob,
uppermost, the nigre at the bottom, and the pure soap (or
neat soap, as it is called) in the middle. The scum is next
taken off, and the soap is cleansed — i.e., the neat soap is
removed into the frames.

The dark-coloured nigre may be afterwards used for
mottling, or for inferior sorts of yellow soap.

2°. If tallow, or other grease, be employed, without any
palm oil, the following procedure is sometimes adopted :* —
2000 Ib. of the fat, 600 Ib. of rosin, and from 150 to 175
gallons of soda lye of specific gravity 1.075 *° I'I5° (I5° to-
30° Tw.) are run into the boiler, and, when the whole is
melted, it is boiled, with continued stirring to prevent the
rosin adhering to the bottom and sides of the boiler. If
there is a great swelling of the mass, the heat must be

* MusrBATi's " Chemistry," ii. 880.

HOUSEHOLD SOAPS. 103

lessened. The first boiling should be continued not more
than two or three hours, on account of the ease with which
the combination is effected. After six hours' repose the
spent lye is withdrawn, more lye is run in, and the whole is
again boiled for about three hours. Another repose of six
hours is now allowed, the spent lye is again drawn off, and
fresh lye afterwards added. These boilings, £c., are con-
tinued day after day till the proper consistence, which is
ascertained in the manner already described (pp. 91, 95),
has been attained. If the soap is not yet satisfactory, it is
requisite to add more lye, and to re-boil \ but if the examina-
tion shows it to be finished, it is boiled up briskly, the heat
is withdrawn, about 6 gallons of lye are thrown in to cool
the soap, and two hours afterwards the liquor is run off.
From 12 to 16 gallons of water are now added, and the
whole is again briskly boiled, stirring constantly till the
soap is melted. A little of the boiling paste is now removed
on a wooden spatula, and, if it run clear from the lye, more
water is added, and the boiling is continued. If it should
not run, too much water has already been added, and about
a gallon of a strong solution of salt or of lye must be
thrown in. .

3°. Another and, as some think, better plan* is to make
a rosin soap, or, more accurately, an alkaline, resinate, and a
tallow soap separately, and to mix the two in the boiler,
where they are kept in a state of ebullition for some time,
until a uniform mixture results. Salt is then added, and,
after treatment similar to that already described, the soap
is ready for the frames.

4°. Dunn's Method, t — Into each of the ordinary
coppers, a circular ring of ij-inch pipe, perforated with

* RICHARDSON and WATTS, " Technology," vol. i. pt. iii. p. 686.
f Quoted in ibid.

104 SOAPS.

holes, is fixed just far enough above the bottom to allow
the free movement of a stirrer beneath it. This circular
ring of pipe is supplied with air from a cylinder blast, or
other suitable forcing apparatus, being connected therewith
by means of a pipe which passes to the top of the copper,
where it is furnished with a stop-cock and union- joint, for
the purpose of connecting, or disconnecting, the parts of
the pipe within and without the pan. For a clear yellow
soap, 90 gallons of lyes of sp. gr. 1.14 made from strong
soda-ash are introduced into the pan. The fire is kindled,
and about 2050 Ib. of grease are added, and, as soon as the
lye boils, the blast is set in action. A brisk fire is kept up,
so as to maintain the materials as near ebullition as pos-
sible. When the lyes are exhausted, more lye is gradually
added until the fatty matter is killed. 550 Ib. of fresh
rosin are then added, a bucketful at a time, with more
lye occasionally, until 300 gallons, of the strength above
mentioned, have been used. The blast is kept in action the
whole time if the fire draws well ; if not, it is advisable to
stop the blast for a while before adding the rosin, to allow
the mixture to approach ebullition. "When the whole of
the rosin is melted and completely mixed with the soapy
mass, and the strength of the lyes taken up, the blast must
be stopped, and a brisk boiling given. The whole is then
left to rest, that the spent lyes may separate and settle.
These are drawn off, and the soap brought to strength on
fresh lyes, as in the ordinary process.

During the operation of the blast the soap must be kept
in what is technically called an open or grained state, and
for this purpose salt, or brine, is to be added when necessary.
Experience proves that it is better not to make a change
in the lye during the operation of the blast where lye of
the strength mentioned is used, but if weaker lye is em-
ployed one or more changes may be made. It is also found

HOUSEHOLD SOAPS, 105

desirable that the soap should be kept in a weak state
during the action of the streams of air through the materials;
otherwise the soap is apt to swell up from the air hanging
in the grain, and this is troublesome to get rid of, requiring
long boiling. If dark-coloured materials are used, it is
well to keep the blast in operation three or four hours after
the rosin is melted, provided the soapy mass is kept weak
and open or grained.

When a charge is to be worked upon a nigre, such nigre
should be grained, and the spent lye pumped, or drawn off,
as usual, and the fresh charge added in the way mentioned
above, using less or more lye in proportion to the quantity
and strength of the nigre, and taking care not to turn on
the blast until there is sufficient grease present to make
the nigre weak.

5°. Meinecke's Method.* — This is an attempt to pro-
duce rosin from turpentine in the soap-pan which shall
be at once available for making soap. The rosin is
added, as it occurs in white turpentine, and this, on boil-
ing, gives off its volatile oil, which has to be condensed
and saved as an incidental product, thereby decreasing-
the expense of the soap. To condense the spirit of tur-
pentine, the soap-pan must be furnished with a still-head
and worm for cooling the vapours. The operation is as
follows : — 1000 Ib. of white turpentine are melted in the
copper by steam, with 800 Ib. of tallow, or inferior fat,
and when the mixture reaches 108° F. it must gradually
receive, with constant stirring, 800 Ib. of caustic-soda lye
containing 30 per cent, of dry soda. The union of the
materials is very rapid at this temperature ; the acids of
the rosin and of the fat are completely neutralized by the
alkali, and converted into liquid soap. To promote the

* KICHARDSON and WATTS, "Technology," vol. i. pt. iii. p. 687.

io6 SOAPS.

vaporization of the essential oil of turpentine, salt or brine
is then added, the still-head luted to the copper and con-
nected with the worm, and the contents of the copper are
boiled up. The steam and oil of turpentine pass over, and
are condensed. When no more oil distils over, the soap is
finished in the ordinary manner.

6°. Jennings' Method. — To curd soap prepared with
tallow or oil and caustic alkali, in the usual manner, is added
about 25 per cent, of colophony, 2 to 4 per cent, of sodium
carbonate, and about i per cent, of aluminium sulphate,
common alum, or other double salt of alumina. The mix-
ture is boiled with water till perfect combination is effected.
To prevent the rosin from precipitating, a small quantity of
dilute sulphuric acid ( i part acid to 9 parts water), amount-
ing to about 2 per cent, of the fats and rosin, is stirred into-
the mixture.

The composition of primrose soap by analysis is :* —

South England. North England.
Fatty acids . . . .62.3 42.66

Soda — as soap . . . . 6.7

„ in other forms . . o.o

Neutral salts . . . . 0.2

Silica o.o

Water 32.8

5-41

1. 21

0-55

0.94

50.40

Total . . . 102.0 ... 101.17

Cost of an Ordinary Yellow Soap. — The following calcula-
tion indicates, approximately, the cost of production of i ton
of ordinary yellow soap at the prices quoted : —

£ s. d.

Tallow — ii cwt. at (say) 255. - . . . . 13 15 o

Kosin — 3 cwt. at (say) 55. . . . . . o 15 o

Alkali — 2 cwt. 3 qrs. (58° at \\d. per unit), 5$. 6d. o 15 i.J,
Labour, &c .300

Total £18 5 ii

* CARPENTEK — SPOK'S "Encyclopaedia," v. 1796.

HOUSEHOLD SOAPS.

107

6. Cocoa-nut-oil, Marine, or " Hydrated " Soaps.

The use of cocoa-nut and palm oils in the manufacture of
soaps has increased to a great extent since artificially pre-
pared soda came into general employment. This is well
shown by the following statistics : —

Imports of

Year.
1820
1830
1840
1850
1860
1870
1880
1881
1882
1883
1884
1885
1886
1887

The behaviour of cocoa-nut oil differs from that of the
other fatty matters in the process of saponification. It is
difficult to make the saponification begin, but, once started,
it goes on with great rapidity, the mixture swelling up
enormously. The resulting soap can only be separated
from solution in the copper by very strong solutions of
common salt. The reason of this is that cocoa-nut-oil
soap is soluble in dilute brine, and is, consequently, avail-
able for washing in salt water. Hence it is called marine
soap. If, however, cocoa-nut-oil soap be prepared in this
way, it contains very little water, and becomes so hard that
it cannot be cut with a knife. The usual method is there-
fore not followed in making this soap. As weak lyes will
not saponify cocoa-nut oil, the operation is commenced by
employing strong lye, of about 20° B. ; and, by having the

Palm Oil.

Cocoa-nut Oil.

cwts.

17*456

8,353

213,476

8,534

315*503

42,428

447*796

98,039

804,326

194,309

868,270

198,602

1,026,378

317,828

819,749

248,476

801,545

136,087

743,5*2

210,874

825,822

245,695

898,481

185,971

993.091

156,667

966,536

183,766

io8 SOAPS.

lye pure and perfectly caustic, the use of salt in cutting
the pan is dispensed with. Saponification is also aided by
the use of potash lye with the soda.

Pure cocoa-nut-oil soap hardens much too quickly to
exhibit any distinct formation of curd, and is, consequently,
incapable of marbling by itself. It is very white, translu-
cent like alabaster, exceedingly light, and forms a good
lather, but always possesses a more or less offensive odour.

Cocoa-nut oil has the very important property of com-
bining with more water than can ever be incorporated with
tallow soap. It really produces no greater quantity of
actual soap than an equal weight of tallow, but it can easily
be made to absorb one-third more water or lye, and, at the
same time, shows no want of consistence or softness, as
would be the case with other soaps.

Cocoa-nut oil is not usually employed alone, but is added
to other oils for the purpose of producing quickly solidifying
soaps containing a large proportion of water, which could
not be obtained from tallow, &c., alone. It is even possible*
to prepare soap on a large scale in a few hours without salt,
und almost without fire, by the use of cocoa-nut oil and
tallow, together with strong lye, by merely warming them
sufficiently to melt the fat, and keeping them constantly in
a state of agitation. Soap prepared in this manner has a
finer appearance, and sets in the mould, so that it can be cut.
It contains, however, nearly all the water of the lye, as there
is very little evaporation in the pan, together with the entire
amount of foreign salts, and, in the fresh state, has less
resemblance to soap than to stiff dough, taking deep. im-
pressions from the thumb, and having a slimy consistence
when squeezed between the fingers. When dried for a length
-of time, there is a copious efflorescence of salts, but it finally

* RICHARDSON and WATTS, " Technology," vol. i. pt. iii. p. 683.

HOUSEHOLD SOAPS. 109

acquires the consistence of ordinary soap. " Marine" soaps
are often met with containing 70 per cent, of water.

If equal parts of cocoa-nut oil and tallow are used, the
smell of the former is scarcely perceptible in the soap. The
boiling of such a mixture is continued till a sample exhibits
the proper consistence under the thumb. Under the same
conditions, tallow could not be saponified alone, but the
sap onin cation begins with the cocoa-nut oil, and the presence
of the cocoa-nut-oil soap carries on the saponification of the
tallow.

Blake and Maxwell's Process. — In this process it was
proposed to form a soap by combining saponified materials,
in the state called soft curd, with a hydrated soap, or neutral
soap not deprived of its water.

The curd soap may be prepared in the usual way, or
it may be made, as preferred by the patentees, by means of
soda lyes of the strength and in the quantity mentioned
below, so as to obtain a soft curd better adapted for com-
bining with a neutral soap. The soap thus formed may be
separated from the water, or excess of lyes, by means of
salt, or concentrated lyes, in the usual way.

The rosin soap is recommended to be prepared as
follows : —

About one-third of the rosin to be used is mixed with a
small quantity of fatty matter, equal to from 6 to 10 per
cent, of the rosin. One-third of the lyes is also mixed with
the rosin, and the mixture is slowly melted. The remainder
of the rosin is then added gradually, by small portions at
a time, as the added portions melt, and, when the whole
is melted, the rest of the lye is introduced. Increased heat
is then applied till the mixture boils, and this is continued
for about three hours, or till saponification is complete, when
the mass will have the consistence of thick glue or paste.

The hydrated soap is prepared in another pan from any

SOAPS.

of 'the fatty matters mentioned below, either singly, or in
combination, and to it are transferred the soft curd, rosin,
and tallow soaps. After boiling together for about two
hours, the soaps will become thoroughly united, and the
compound soap will have assumed an appearance similar to
ordinary soap in process of finishing. The soap should be
removed to the frames within two or three hours after it is
finished, and the frames should be covered so as to retain
the heat as long as practicable.

The following table shows the oily and fatty matters which
may be used for making the soft curd, and the strength and
quantity of the soda lyes deemed most suitable for speedily
effecting their saponification. The weight of lye required
to saponify each 100 Ib. of fatty matter may be found by
dividing the number of degrees by the strength of the lyes
applicable to each kind of fat.

Fat to be used.

Quantity of
Lye in
Degrees BaumtS.

Strength of Lye.
Degrees Baume".

100 Ib. tallow require .
,, palm oil ,,
,, tallow olein ,,
,, rosin ,,

3,800°
3,200

2,800
2,700

I4°-I5°
16-18
16-18
16-22

The fats that may be used for making the Jiydrated soap,
and the quantity and strength of the lyes required for
saponification, are the following : —

Fat to be used.

Quantity of
Lye in
Degrees Baume.

Strength of Lye.
Degrees Baume".

IOC

) Ib. tallow reqi
cocoa-nut oil
palm oil
lard
tallow olein
olive oil
rape-seed oil
linseed oil

lire

3,800°
4,100
3,200
3>4QO
2,800
3,000
2.400
2,400

11°

16-20

18-22

1 8-22

24-28
24-28

HOUSEHOLD SOAPS. in

7. Silicated

The use of sodium silicate as an ingredient of soap was
first proposed by Mr. SHERIDAN in 1835.

It has been stated * that the value of silicated soaps was
first publicly and officially recognized at the International
Exhibition of London in 1862, when a prize medal was
awarded to "W. Gossage & Sons, of Widnes ; but we find the
following paragraph in the " Heport of the Juries, Exhibi-
tion, 1851 " (p. 607) : — "The soap called silicated soap, now
manufactured extensively at Liverpool, is formed by mixing
a basic silicate of soda (made by boiling powdered flint in
a close vessel, under pressure, with caustic soda) with hard
soap in a melted state. It appears to possess remarkable
detergent properties, but is liable to feel gritty in the hand."
Though they may be useful, therefore, for household pur-
poses, they are unsuitable as toilet soaps.

Sheridan's Process. — The method of preparing the sili-
cate is described on p. 27.

The silicate is incorporated with the soap, previously
prepared in the ordinary manner, by mechanical mixture,
and, when the mass has been brought into the proper state
for solidifying, the whole is placed in the moulds.

Gossage's Process. — GOSSAGE'S patent is dated 1854.
His plan for the preparation of the silicate, which differs
slightly from that of SHERIDAN, is described on p. 28.

In mixing viscous solutions of soluble glass with genuine
soap, it is best to commence t the mixing by adding a
portion of the solution at a specific gravity of about 1.300,
and to add the remaining portions required at increasing
specific gravities, so that the average specific gravity of the

* SPON'S " Encyclopaedia," v. 1786.

f KICHARDSOX and WATTS, " Technology," vol. i. pt. iii. p. 713.

112

SOAPS.

whole solution used may be equal to that which has been
found by previous trials to yield a compound soap of proper
hardness when using a genuine soap of the composition
employed.

The temperature of the silicate and of the soap-paste
should be about 160° F. at the moment of mixing, and, to
promote homogeneity, the mixture is stirred up by ma-
chinery. This consists* of a large tub or vessel, A (Fig. 24),
Laving the shape of an inverted cone of about 26 inches

FIG. 24.

internal diameter at its lowest part, 3 feet 6 inches at the
upper part, and 6 feet deep. It is furnished with a central
upright shaft, B, supported by a foot-step, C, fixed to the
bottom of the tub, and, by a journal, D, adapted to a
metallic bridge-piece, E, which is fixed over the vessel and
secured by screw-bolts to its sides. At the upper part of

* RICHARDSON and WATTS, "Technology," vol. i. pt. iii. p. 713.

HOUSEHOLD SOAPS. 113

the shaft is a bevelled cog-wheel working in gear with
another bevelled cog-wheel fixed on a horizontal shaft, S,
which is made to revolve by a band passing round the
driving-pulley, P, and also round another driving-pulley.
The upright shaft is driven at the rate of sixty to eighty
revolutions per minute.

To the upright shaft B is fixed a closed tub or vessel, F
(Fig. 24, i), of such a diameter as to admit of its being placed
within the larger vessel, A, leaving a space of about 2 inches
at the lower, and 6 inches at the upper part ; and to the
outside of this inner vessel are attached, by means of screws
or otherwise, a number of projecting blades, / /, made by
preference of sheet iron, of such a length as to approach
within about J inch of the inside of the vessel A. A spout,
G, having a movable stopper, If, is adapted to the lower part
of the vessel A for the purpose of running off its contents.
The projecting blades //, instead of being attached to
an inner vessel, may also be affixed to the inside of the
upright shaft, and in that case it is best to attach other
projecting blades, K K, to the inside of the vessel A, in
such a manner as to allow the blades //to revolve
between them.

When this apparatus is to be used for the production of
compound soap by mixing genuine soap with the silicate
solution, it is necessary to ascertain previously the highest
temperature at which the mixture will become too thick to
run from the mixing apparatus. For this purpose, a pre-
paratory mixing of the neat soap with the silicate is made
by means of paddles, or crutches, in a vessel capable of con-
taining about J ton of soap, the soap and viscous solution
being added at such temperatures as will yield a mixture
having a temperature at least 10° higher than the tempera-
ture referred to. The contents of the preparatory vessel
are then transferred to the mixing apparatus, and a rapid

ii4 , SOAPS.

revolving motion is communicated to the projecting blades.
The stopper of the spout G -is then withdrawn, so as to
allow the compound soap, in the state of perfect mixture,
to flow from the mixing apparatus, and further quantities
of mixed soap and silicate are then supplied. The mixed
compound soap is then transferred to the ordinary frames,
in which it solidifies on cooling.

Way's Method. — The alkaline silicate is prepared by one
of the methods described on pp. 27, 28, 29.

To produce 100 Ib. of soap, the operator puts into the
soap-pan 11.5 per cent, of bleached palm oil, 11.5 per cent.
of cocoa-nut oil, and 30.6 per cent, of soda lye of 36° Tw.
These ingredients are boiled till the soap becomes stiff, and
then there is added 44 per cent, of the solution of silicate of
36° Tw. The boiling is now continued till the soap becomes
thin and limpid, when 2 .4 per cent, of common salt is thrown
in, and the boiling continued for three or four hours. After
this the soap may be cleansed, either at once, or after it has
been allowed to stand for a few hours.

If open steam is used, it is best to nave the solution of
silicate and the lye of greater strength than that mentioned,
in proportion to the quantity of water which is condensed
from such steam into the soap-pan.

Other siliceous matters, such as powdered soap-stone,
porcelain earth, pipe-clay, and fuller's earth, are also used
for mixing with soap instead of soluble glass.

Davis's Alk-alumino-silicic Soap* is a mixture of
ordinary soap with fuller's earth, pipe-clay, and pearl-ash
or soda, by which the cost of the soap is said to be much
diminished, while it is claimed that its detergent properties
are improved. It is prepared by adding, to every 126 Ib. of
soap-paste, 56 Ib. of fuller's earth, slaked or dried, 56 Ib. of

* RICHABDSON and WATTS, " Technology," vol. iii. pt. i. p. 714.

HOUSEHOLD SOAPS. 115

dried pipe-clay, and 112 Ib. of calcined soda or pearl-ash,
all reduced to powder, and sieved as finely as possible.
These ingredients are then thoroughly incorporated by
stirring or crutching. The mixing must be very perfectly
and rapidly done before the pasty mass cools. To obviate
any objection against the use of this soap for washing white
linens, a modification of the above process is proposed, by
which the use of fuller's earth is omitted, leaving the pro-
portions, for every 120 Ib. of soap, 112 Ib. of dried pipe-clay
and 96 Ib. of calcined alkali. A soap thus prepared is said
by the patentee to be useful for general purposes at sea,
and for washing white linen in salt water.

For the preparation of a soap for washing white linen in
fresh water, the process is still further modified by using
112 Ib. of soap-paste, 28 Ib. of dried pipe-clay, and 36 Ib. of
calcined soda ; and to prepare a toilet soap, either for fresh
or salt water, 28 Ib. of fuller's earth, slaked or dried, and
20 Ib. of calcined soda are mixed with 112 Ib. of perfumed
curd soap.

DUNN devised and patented a special boiler for combining
soap with sodium and potassium silicates under pressure
(see p. 65). The soap is prepared from tallow 7 parts,
palm oil 3 parts, rosin 3 parts, caustic-soda lye (21° B.)
140 to 150 gallons. These having been placed in the boiler,
heat is applied till the pressure is suflicient to permit the tem-
perature in the boiler to rise to 310° F. This temperature
is maintained for an hour, and the soap is then discharged
into the vessel at the side of the apparatus. The silicate is
prepared as previously described (p. 29).

8. Sulphated Soaps.

These are prepared by a process patented by Dr. NOR-
MANDY. The object is to impart hardness to soaps made
from inferior fats, and also to soaps containing large

I 2

n6 SOAPS.

quantities of rosin. "Without this addition, such soaps are
apt to be too soft, and, dissolving too freely in water, are
very wasteful. The process thus enables a large class of
fats, otherwise unsuitable, to be employed in soap-making.

The soap is first prepared in the usual manner, and when
ready for cleansing, the salts are crutched in. For every
80 Ib. of soap the proportions are 28 Ib. of sodium sulphate
(Glauber's salt) and 4 Ib. of potassium carbonate, or 2 Ib.
of potassium carbonate and 2 Ib. of sodium carbonate.
When the whole has been thoroughly mixed, the soap is
ready for the frames.

Another process for the preparation of salinated soaps is
that patented by NORMANDY and SIMPSON. The soap may
be prepared in the usual way from tallow, bone-fat, lard,
palm oil, &c., and after the soap has been curded by means
of salt, or strong lye, the lye is allowed to settle down, and.,
after it has been drawn off, a certain quantity of fresh lye
and cocoa-nut oil is added, and the whole well boiled till a
homogeneous mass results having the appearance, except as
regards colour, of fitted yellow soap. The desired proportion
of sodium sulphate, sulphite, or hyposulphite is next intro-
duced, the mixture boiled, and the soap afterwards trans-
ferred to the frames. This method, it is claimed, will yield
a mottled soap of better consistence and appearance than is
obtainable from the same fatty materials in the ordinary
way, and without separation of lyes in the frames.

Sodium hyposulphite crutched into the soap increases its
hardness, like the sulphate, and the soap so treated is less
liable to effloresce. It has also the property of removing
the chlorine, which bleached fabrics have a tendency to
retain, and by which they are exposed to deterioration.

HOFFMANN, MILLER, URE, and MUSPRATT all commend
the usefulness of this process, but these soaps are not so
much used as formerly.

CHAPTER VIII.
TOILET, OH FANCY, SOAPS.

THE manufacture of these soaps is either carried on as a
separate business, or as a branch of the ordinary soap-
maker's work, or of the perfumery business. The stock
soap is either a specially prepared article — cold-process
soaps being largely used — or a soap prepared in the ordinary
manner.

It will be convenient to consider this branch of soap-
.making under the following heads : —

i°, The materials; 2°, The apparatus ; 3°, The manipula-
tion; 4°, Formulce; 5°, The French

i°. The Materials.

These are chiefly white curd soap, fitted soaps, and soaps
prepared from palm and almond oils. Cocoa-nut-oil and
rosin soaps are also used for some toilet soaps. They should
.all be of superior quality.

2°. The Apparatus.
a. For the Preparation of the Soa%).

The selected soaps have first to be sliced. This is accom-
plished either by a cutter, or planing-kiiife, fixed on a
strong wooden bench, and furnished with a drawer to re-
ceive the soap shavings as they are sliced off from the
bars. (Fig. 30, p. 136.)

iiS

SOAPS.

Or a cutting machine turned by a handle may be em-
ployed where larger quantities are operated upon. The bar
of soap is pushed down an inclined plane against the edge
of one of the blades, the handle is turned, and the shavings
fall into a box placed underneath. By this machine, 2 cwt.
of soap may be cut in an hour. (Fig. 31, p. 136.)

b. For lie-melting the

The most convenient pans for this purpose are small
steam-jacketed pans, of 2 cwt. to ^ ton capacity, according

FIG. 25.

A, The shell. B and C, Steam-coils. D, Grating for soap to rest
upon. E, Discharge-gate. F, Small pipe for admitting
direct steam through perforations. G, Feed-spout. H H,
Floor. J, Dry steam. /, Exhaust steam. K, Open steam.

TOILET, OR FANCY, SOAPS. 119

to the extent of business ; or a WHITAKER re-inelter (Fig.
25) may be employed.

The method of using this, apparatus is as follows: — Fill
the re-melter with soap, close the discharge-gate, E, and let
the open and dry steam on for ten minutes. Then shut off
the open steam, open the discharge-gate, and run off the
soap into the steam crutcher till the latter is full, and run
the crutcher from three to five minutes until the soap is
thoroughly mixed. As fast as the soap lowers in the re-
melter, add more stock, so as to keep the vessel full, as the
soap will thus melt more quickly. The open steam should
be let on two or three times, for ten minutes at a time,
while filling the crutcher, some kinds of soap requiring
more than others.

This machine is also used for re-melting soap scraps, with
the object of saving fillings, such as sodium silicate, talc,
and other substances.

c. Frames.

These are smaller than those used for household soaps.

d. Moulding.

For moulding the tablets, various kinds of apparatus are
employed. Fig. 26 will give the jrIG 26.

reader an idea of the modus operandi.
A A is a table to which the press is
fastened by bolts and screws. E is
the lower portion of the mould ; the
upper portion is attached to the
piston D, which is worked by the
lever (7, connected with the cast-iron
pillar B.

e. /Stamping.

For this purpose the press Fig. 27 may be employed.

120

SOAPS.

In this machine* there are two spiral springs, A and B,
by which the cake of soap is immediately expelled from the
box (7, as soon as it is pressed. D is a rope suspending a

FIG. 27.

wooden rod, E, which serves as a support to the bottom of
the die during the pressure. The box C is movable, being
merely fastened by screws, and, when necessary, may be
replaced by others of different sizes. The die from which
the tablet is to receive a device, or name, is screwed to the
top of the box (7, and may also be changed when required.

Another form of stamping-press is that shown in Fig. 28,
which is worked by hand.

Fig. 29 represents a stamping-press worked by steam.

3°. The Manipulation.

The numerous varieties of fancy soaps may be classed as
(a) opaque and (b) transparent.

* MORFIT, p. 185.

TOILET, OR FANCY, SOAPS.

121

a. Opaque Toilet Soaps.

In the manufacture of these soaps, the operator may
either (A) prepare the article directly by the little-pan or
cold process ; or (B) he may re-melt and refine, and after-
wards perfume soaps prepared in the ordinary manner.
Or, to prepare the finest toilet soaps, he may adopt the
French system (p. 136).

FIG. 28.

A. COLD PROCESS. — The selected fats, such as clarified
beef marrow, clarified lard, sweet-almond oil, cocoa-nut oil,
castor oil, and other fats of good quality, are melted to-
gether, and, if necessary, strained. Some makers now add

122 SOAPS.

the alkaline lye to the melted fat ; others heat the lye, and
add the melted fat to it. In either case the added materials
are introduced gradually with continual stirring, and care is

Fia. 29.

taken that the temperature does not rise much above
150° F. (65.5° C.). The next stage is to run the soap into
the cooling-frames, and allow it to repose.

The low temperature at which this operation is conducted

TOILET, OR FANCY, SOAPS. 123

is extremely favourable to the use of delicate perfumes.
These are, of course, best introduced at as late a stage of
the process as possible, so as to prevent loss, yet before it is
too late to secure complete admixture with the mass.

The advantages and disadvantages of the cold process
have been already specified (p. 88).

B. RE-MELTING. — The soap for this purpose should be
a good yellow fitted soap of recent manufacture, and as
neutral as possible.

i°. After having been sliced by one of the machines pre-
viously mentioned (p. 117), it is transferred to the melting-
pan. It must not, however, be all put in at once, but, after
the first portions have been melted and crutched, so as to
produce uniformity, a little more of the cut soap is added,
the pan covered till this has also become fluid, and the
whole again stirred. Other portions are then introduced,
and successively melted and crutched as before, so as to
effect intimate mixture. When the paste begins to cool,
the desired colouring matters are mixed with it, and after-
wards the selected perfume, reserving the latter to the last
so as to avoid any unnecessary loss by evaporation. At
this stage also, if desired, a portion of glycerin may be
introduced.

2°. FRAMING. — The soap is now ready for the frames,
into which the pasty mass may be transferred by ladles.
The frames are covered with cloths, so that the cooling may
be gradual.

3°. FINISHING. — In a day or two it will be sufficiently
hard to cut into bars and tablets of any desired size. The
cakes are then trimmed at the edges and corners, moulded,
and stamped.

Savonettes, soap-balls, or wash-balls are shaped by
rotating blocks of soap upon a soap-scoop, made of brass
with sharp edges, or the paste may be first formed into

124 . SOAPS.

.balls by hand, and, when quite dry, finished by turning
them with a lathe.

The surface of tablets or of savonettes may be polished,
either by rubbing with a little spirit on a cloth, or by
exposure to the action of wet steam for a few seconds.

b. Transparent Soaps.

Two methods are in use for the manufacture of trans-
parent soaps — (i°) Solution of stock soaps in alcohol;
(2°) The cold process.

i°. PREPARATION BY SOLUTION OF SOAP IN ALCOHOL. —
It has been long known that a concentrated hot solution
of soap retains its transparency on cooling. This fact is
applied to the production of transparent soaps. As any
non-soapy matters that may be present in the stock are,
with the exception of free caustic alkali, insoluble in strong
spirit, a transparent soap properly prepared by the alco-
holic process from a good soap is necessarily of a high
degree of purity, and is justly valued for toilet purposes.
Makers do not all operate in exactly the same way, but the
following is an outline of the process generally : —

1. Yellow soap of good quality, reduced to shavings, and
dried, is introduced into a still of sufficient capacity to-
gether with alcohol (strength about 55 to 60 o.p.). Some-
times the shavings are previously powdered, and in this
country, owing to the high spirit duty, methylated spirit,
instead of pure alcohol, is employed, in the proportion of
about 5 gallons to i cwt. of dried soap. Most makers also
add a certain proportion of glycerin. The still is heated
by steam, or by a hot-water jacket, as the direct action
of fire would interfere with the appearance of the product.

2. Moderate heat is continued till about one-fifth to one-
•third of the spirit has passed over.

3. The clear residue, free from any deposited matters, is

TOILET, OR FANCY, SOAPS. 125

run into moulds to form bars, and when these are cold they
are cut into cakes.

4. The cakes, after drying sufficiently, are bevelled,
polished, and stamped.

The cakes are not at first transparent, and require to be
kept in the drying-room for some months before they are
ready for sale. During this time evaporation of the remain-
ing alcohol and water takes place, the colour deepens, and
much of the odour of the methylated spirit goes off. If too
much spirit is left in the soap at first, it is liable to be-
come opaque, and, if there is too little, the soap will not
harden properly. The finished soap contains only from
9 to 1 2 per cent, of water, and no spirit.

Scents and colouring matters, when desired, are mixed
with the dissolved soap at the commencement of the pro-
cess. The colouring matters are introduced in alcoholic
solution — for red, tincture of alkanet ; for yellow, tincture
of turmeric, annatto, or saffron ; for orange, a mixture of
alkanet and turmeric ; for green, tincture of chlorophyll,
or a mixture of blue and yellow ; for blue, tincture of
indigo-carmine ; &c.

2°. THE COLD PROCESS. — Certain kinds of soaps* pre-
pared by the cold process, especially castor-oil soap, have a
natural tendency towards a somewhat transparent appear-
ance, which is increased by the addition of spirit, glycerin,
sugar, or petroleum. With the employment of a consider-
able proportion of sugar (15 to 30 per cent.) a comparatively
large amount of tallow is admissible without interfering
with the transparency, provided that complete saponification
is insured. Dr. WRIGHT gives the following formula for
the production of a transparent soap by this process, which
will be without great excess of free alkali or of sugar : —

* Dr. C. R. A. WEIGHT, Cantor Lectures, May 1885, p. 25.

126 SOAPS.

Heat to 149° F. (65° C.) a mixture of tallow 20 parts,
palm oil 12 parts, castor oil 8 parts, and then gradually
run in 20 parts of caustic-soda lye at 38° B. When inter-
mixed, crutch in 20 parts of strong alcohol, 20 parts of
glycerin, and 10 of syrup containing half its weight of loaf-
sugar. Colours and perfumes may be added as desired.

As an" illustration of the materials sometimes used in this
class of soaps, WRIGHT quotes the following formula :* —

Melt the following with agitation: — 10 kilos, cocoa-nut
oil, 10 kilos, castor oil, 8 kilos, neutral tallow, and saponify
them at 122° F. (50° C.) with 14 kilos, of caustic soda at
38° B., and continue stirring until pastiness sets in. Add
8 kilos, loaf-sugar in 8J- litres of water at 185° F. (85° C.),
taking care to bring it in gradually. As soon as the soap
begins to solidify at the sides, the boiler is jacketed with
a water-bath, kept at 176° F. (80° C.), until the soap has
attained the proper consistency and the scum has separated.
Add 20 to 30 per cent, of loading, agitate well, and then stir
in a boiling solution of I kilo, crystallized soda in a litre of
water; dye, perfume, and finish off the batch as usual. The
loading is made from mineral oil and soap shavings, the
petroleum being previously deodorized by means of bleach-
ing-powder solution and hydrochloric acid, and subsequent
treatment with chalk to remove adhering acid. 30 kilos,
of the oil thus purified are heated to 122° F. (50° C.), mixed
with 2 kilos, of well-dried soap shavings, and heated until
a sample taken out solidifies on cooling.

On this formula WRIGHT makes the following useful
observations : — " It is evident from the above that even
without the loading the resulting mass would not contain
as much as half its weight of actual soap, for the ingredients
consist of 28 kilos, fatty glycerides (representing a little

* "'Journ. Soc. Chem. Ind." April 1883.

TOILET, OR FANCY, SOAPS. 127

more than the same weight of anhydrous soda soap — about
29 kilos.) and 32^ kilos, of water, soda, and sugar, so that,
when 30 per cent, of loading is added, the resulting mass
would not contain much more than one-third its weight
of actual soap. On the other hand, the total alkali used
(partly as caustic-soda solution, partly as crystals) repre-
sents about 113 per cent, of the amount chemically equiva-
lent to the fatty matters, furnishing, consequently, a soap
with an excess of free alkali equal to one-eighth of that
combined as soap — a quantity very far in excess of that
compatible with good quality as regards injurious action on
tender skins. The quantity of sugar prescribed represents
some 13 per cent., reckoned on the mass without loading,
and about 2 7 per cent, of the actual soap formed.

" This formula, apart from the loading, results in the
production of an article of distinctly better quality than
most of the transparent soaps of this kind now sold in
Great Britain, for these soaps usually contain a still larger
excess of alkali (ranging from 15 to 25 per cent., and even
more being often found), whilst the amount of actual soap
in tablets fresh from the factory (and not dried by exposure
in shop windows) rarely exceeds 45 per cent., so that these
articles are about as much a compound of sugar-candy and
soda crystals as they are soaps, if not more so."

These soaps are often termed transparent glycerin soaps.

The following formulae are said to give satisfactory re-
sults : —

i. Melt together 500 parts of suet, the same quantity of
Ceylon cocoa-nut oil, 250 parts of castor oil, 50 parts of
palm oil, and 500 parts of glycerin. Saponify the mixture
at about 75° C. with 650 parts of soda lye of 1.38 sp. gr.
The soda solution should be added gradually, and the whole
well stirred during the saponification, which will be com-
pleted in about five minutes. The soap is now removed

128 SOAPS.

from the source of heat, and mixed with 600 parts of strong
alcohol (or methylated spirit), the whole being well stirred
until it is clear. 150 parts of simple syrup are then
added, together with the perfumes. It is then poured into
moulds.*

2. 20 Ib. tallow, 12 Ib. palm oil, 8 Ib. castor oil, 20 Ib.
38° lye, 20 Ib. 96 per cent, alcohol, 20 Ib. glycerin, 5 Ib.
sugar dissolved in 5 Ib. water. Heat the tallow and palm
oil, add the lye, and saponify; then add the alcohol, and,
when the combination is complete, introduce the glycerin.
The soap may be perfumed with oil of bergamotte 250 grams,
citron 90 grams, lavender 20 grams, neroli 30 grams, rose-
mary 5 grams, and a few drops of otto of roses dissolved
in i Ib. of 96 per cent, alcohol and coloured with saffron
substitute, t

CRISTIANI^ gives the two following formulae : —

3. Transparent Soa}}. — Tallow 209 Ib., caustic-soda lye
40° B. 94.6 Ib., alcohol no Ib.

To the melted grease add one-half the alkali, keeping the
heat as low as possible — about 120° F. When, with con-
stant stirring, the fresh lye is combined, add the remainder
of the lye, to which has been previously added the alcohol,
the heat being well regulated. Saponification takes place
rapidly. Add the perfume, cool, pour into the frames, and
continue the cooling very gradually. The transparency will
not be apparent till the soap has been exposed to the air
for some time. To perfume the quantities given above,
2.2 Ib. of mixed essences will be required.

4. Transparent Glycerin Soap. — Tallow (mutton) 44 lb.7

* "Pharm. Zeitung," 1879, p. 719; "Year Book of Pharmacy,"
1880, p. 344.

f " Seifensieder Zeitung," 1884, p. xxiii.

$ " Treatise on Soap and Candles," pp. 422, 423.

TOILET, OR FANCY, SOAPS. 129

cocoa-nut oil 44 lb., castor oil 22 lb., glycerin (pure)
22 lb., caustic lye 40° B. 57 lb., alcohol (96 per cent.)
48.4 lb., water 9.9 lb.

Melt the grease at 104° F., and add the alkali gradually,
keeping the heat low to prevent evaporation, and stir con-
stantly. "When the lye has been absorbed, after three
or four hours' stirring, add the alcohol, which should be
warmed, and stir till the whole becomes cool. Then add
the glycerin, and, when this has been mixed, the water
and perfumes. Turn into frames, pouring slowly. Very
superior, if well made.

A cheap transparent soap may be made as follows :* —
Cocoa-nut oil 10 kilos., castor oil 10 kilos., tallow 8 kilos.,
caustic-soda lye 38° B. 14 kilos.

Saponify at 112° F. (50° C.), and stir till pasty. Then
add gradually 8 kilos, loaf-sugar in 8J litres at 185° F.
(85° C.); cool and frame.

4°. Formulae.

Ammoniated Soap.t — A soap made from 8 parts of
stearic acid, 4 cocoa-nut oil, i potash, i soda, 6 water,
is cut into shavings and placed in a retort, in which it is
subjected to the action of gaseous ammonia, at a pressure
of 15 lb. per square inch, till thoroughly permeated by it.

Almond Soap. — Oil of almonds by weight 21 oz., solu-
tion of caustic soda (sp. gr. 1.334) by weight 10 oz. Add
the lye to the oil in small portions, stirring frequently,
leave the mixture for some days at a temperature of from
64° to 68° F., stirring occasionally, and, when it has acquired
the consistence of a soft paste, put it into moulds till

* " J. Soc. Chem. Ind." 1883, p. 181.
f C. K. HUXLEY, English patent 3441, March 17, 1885.

139 . SOAPS.

sufficiently solidified. It should be exposed to the air for
one or two months before it is used.

Beef-marrow Soap.* — To 500 Ib. of beef marrow add
250 Ib. of caustic-soda lye of 36? B., stir constantly and
gently, and heat the mass till it becomes soluble in water.
In this state dilute with 2000 parts of boiling water, and
pour in 1000 parts of brine (containing 180 parts of common
salt), with constant stirring. After allowing some time for
repose, pour into the frames, and leave for a day or two to
set thoroughly.

Bitter-almond Soap. — Pure white soap 10 kilos., oil of
bitter almonds 120 grams. Not coloured.

Or, white tallow soap 56 Ib., oil of almonds | Ib. For
inferior kinds, nitre-benzol is employed instead of oil of
almonds.

Moating Soap. — Good oil soap 14 Ib., water 3 pints.
Melt together by aid of steam or water bath, and assiduously
beat together until the mixture has at least doubled its
volume. The capacity of the pan for 14 Ib. of soap should
be about 1 8 gallons. Frame and cool. The thickness of the
soap in the frames should not be more than 6 or 7 inches. In
about a week or less it will be ready for cutting. Perfume,
as desired. Colour with J to i drachm of vermilion per Ib.

Glycerin Soap. — Any mild soap, being melted, has
glycerin intimately mixed with it in the proportion of -^th
to -^t h of the weight of the soap.

Perfume with oil of bergamotte or rose-geranium mixed
with a little oil of cassia, to which sometimes a little oil of
bitter almonds is added.

Honey Soap. — White Marseilles soap 4 oz., honey 4 oz.,
benzoin i oz., storax J oz. Mix well in a marble mortar.
"When thoroughly mixed, melt over a water bath, pass

* MORFIT, " Treatise on Soap," p. 244.

TOILET, OR FANCY, SOAPS. 131

through a fine sieve, and run into moulds. Divide into
cakes.*

The article commercially vended under this name rarely
•contains any honey. It may be prepared as follows : —

Palm-oil soap and olive oil of each i part, curd soap
3 parts ; melt together.

Perfume with oil of verbena, rose-geranium, or ginger-
grass.

Or, a neat yellow soap is mixed with 5 per cent, sodium
carbonate, or silicate (59 J° B.), the whole crutched, and per-
fumed with oil of citronella.

Lard Soap. — This soap is prepared by the cold process,
as follows : — Melt 112 Ib. of lard by gentle heat, and add
half the lye, prepared by dissolving 56 Ib. of caustic soda to
mark 36° B. Agitate well without allowing the mixture to
Tboil, and when the incorporation is complete the remainder
of the lye is gradually introduced. The temperature is kept
under 149° F. When the paste has sufficient consistence,
and has no greasy feel when pressed between the fingers,
it may be run into the frames. The desired perfume is
added while the soap is in the pasty state. In about two
-days it will have become sufficiently solid to be cut into
tablets and pressed. This soap is very hard, and of a brilliant
whiteness.

Miahle's Neutral Soap. — In a communication to the
French Academy,t M. Miahle describes a soap which he
states combines the advantages of being prepared without
heat, and thus avoiding the loss of the glycerin in com-
bination with the fatty matters, and of being free from that
alkalinity generally present in soaps prepared in the cold.
In its preparation the ordinary toilet soap, made without

* DUSSAUCE, " Treatise on the Manufacture of Soap," p. 638.
f " Pharm. Journ." iii. 665.

K 2

132 SOAPS.

heat, is cut into shavings and exposed, in a properly closed
chamber, to the action of carbonic acid gas. The soap
absorbs a quantity of the gas proportionate to the quantity
of caustic soda which has escaped saponification, and by the
transformation of the free alkali into bicarbonate it loses all
its causticity. It then constitutes a perfectly neutral soap,
containing all the glycerin of the fatty bodies employed in
its manufacture, and a certain quantity of bicarbonate of
soda.

Samphire Soap is Messrs. Field's recently patented
article, which is saponified by the use of iodized potash,
obtained from seaweed ashes, with palm oil and olein. The
resulting soap is subsequently milled, after completely ex-
pelling the water, and is de-alkalized by the introduction of
an ammoniacal salt.

Savon au Bouquet. — White tallow or lard soap 10
kilos.*

Perfume with oil of bergamotte 15 grams, neroli 15
grams, sassafras 10 grams, thyme 10 grams.

Colour with 100 grams brown ochre. The oil of neroli
may be replaced by oil of lavender, and oil of cloves,.

10 grams, may also be added.

Savon a 1'Huile de Cannelle (Cinnamon Soap). — Pure
palm soap 5 kilos., tallow soap 5 kilos.

Perfume with oil of Chinese cinnamon 80 grams, sassa-
fras 20 grams, bergamotte 30 grams.

Colour with 80 grams yellow ochre and 20 grams burnt
sienna.

For inferior descriptions, oil of cassia is used instead of

011 of cinnamon.

Savon au Fleur d' Or anger. — White tallow soap 6
- kilos., pure palm soap 4 kilos.

* i kilogram = 2.20 Ib. Avoir.

TOILET, OR FANCY, SOAPS. 133

Perfume with oil of Portugal 140 grams, oil of amber
i o grams. Or with oil of geranium 40 grams, oil of neroli
50 grams.

Savon au Muse. — White tallow soap 5 kilos., pure
palm soap 5 kilos.

Perfume with oil of bergarnotte 50 grams, roses 5 grams,
cloves 5 grams, musk 10 grams.

The musk is prepared thus : — Pound 10 grams of musk
in a mortar, with an equal weight of sugar, and 5 grams
of pure potash; then add 160 grams of alcohol gradually,
triturate for a quarter of an hour, pour the mixture into a
flask, and leave it for two to four weeks, shaking it from
time to time. Then filter, add the whole of the nitrate to
the 10 kilos, of soap, and afterwards the other perfumes.

Colour with 80 grams brown ochre.

Savon a la Rose. — White tallow or lard soap 10 kilos.

Perfume with oil of roses 40 grams, cloves 15 grams,
•cinnamon 10 grams, bergamotte 30 grams, neroli 10 grams.
Or with oil of roses 25 grams, geranium 60 grams, cloves
15 grams, Chinese cinnamon 10 grams.

Colour with 60 or 80 grams of vermilion.

Savon a la Vanille. — White tallow soap 10 kilos.

Perfume with tincture of vanilla 500 grams, oil of roses
5 grams.

Colour with 100 grams of burnt sienna.

Savonettes, or Wash-balls.* — These are made of any
of the mild toilet soaps, scented at will, and sometimes with
the addition of starch. The spheroidal form is given to
them, as described on p. 123.

i. Curd soap 3 lb., finest yellow soap 2 Ib. (both in
shavings), soft water f pint. Melt by a gentle heat, and
stir in powdered starch i| lb. When the mass has con-

* COOLEY'S " Encyclopaedia," ii. 1464.

134 SOAPS.

siderably cooled, add essence of lemon or bergamotte i| oz.r
and make into balls.

2. Camphor. — Melt spermaceti 2 oz., add camphor cut
small i oz., dissolve, and add the mixture to white curd
soap 1 1 lb., previously melted by the aid of a little water
and gentle heat, and allowed to cool considerably. These
balls should be covered with tin-foil.

3. Honey. — Finest yellow soap 7 lb., palm oil \ lb.
Melt, and add oil of verbena, rose-geranium, or ginger-grass:
i oz., or oil of rosemary J oz.

4. Mottled. — (a) Red : Cut white curd or Windsor soap
(not too dry) into small square pieces, and roll these in-
powdered bole or rouge, either with or without the addition
of some starch ; then squeeze them strongly into balls, ob-
serving to mix the colour as little as possible, (b) Blue :
Koll in powder blue, and proceed as before, (c) Green :
Roll the pieces in a mixture of powder blue and bright
yellow ochre.

By varying the colour of the powder, mottled savonettes-
of any colour may be produced.

5. Sand. — Soap (at will) 2 lb., fine sand i lb. ; perfume
if desired. For finer qualities, finely powdered pumice-
stone is substituted for sand.

6. Violet. — Palm-oil soap 4 lb., starch 2 lb., finely pow-
dered orris root i lb.

Shaving Paste. — i. Naples soap 402., powdered Castile
soap 2 oz., honey i oz., essence of ambergris and oils of
cassia and nutmegs of each 5 or 6 drops.

2. White wax, spermaceti, and almond oil of each J oz. ;.
melt, and, whilst warm, beat in two squares of Windsor
soap, previously reduced to a paste with a little rose water.

3. White soft soap 4 oz., spermaceti and salad oil of
each \ oz. ; melt together and stir till cold. Scent at will.

When properly prepared, these pastes produce a good

TOILET, OR FANCY, SOAPS. 13$

lather, with either hot or cold water, which does not dry on
the face.

Windsor Soap. — Plain. — The best kind is made from
olive oil i part, tallow 8 or 9 parts, saponified with
caustic-soda lye, and scented, after removal from the pan,
with oil of caraway and a little oil of bergamotte, lavender,
or origanum, in the proportion of about 2 Ib. of the mixed
oils per cwt. of soap. A little oil of cassia, or of almonds,
or of the essences of musk and ambergris may be also added.
The oil of caraway may be replaced by a mixture of equal
parts of the oils of rosemary and lavender.

Ordinary plain Windsor soap is made from curd soap,
scented, while pasty, with oil of caraway, and a little oil of
bergamotte, lavender, or origanum, in the proportion of about
i J Ib. of the mixed oils per cwt.

Brown. — The colour of this variety was originally the
effect of age upon the plain white soap, but is now pro-
duced by the addition to the above of a little brown colour-
ing matter, such as caramel, umber, or brown ochre.

Weise's formula.* — 40 Ib. tallow and 15 to 20 Ib. olive
oil are saponified with soda lye of 19° B., and the soap is
treated with lye of 15°, and finally with lye of 20°, the
process being conducted as for a curd soap, except that no
excess of alkali is to be used. When boiled clear, the soap
is left in the boiler for six or eight hours, then completely
separated from the lye, placed in a flat mould, and pressed
till it no longer exhibits any flux, to prevent it from
mottling. To perfume the above-mentioned quantity, add
oil of cumin 10 oz., oil of bergamotte 6 oz., oil of lavender
3 oz., oil of origanum i oz., and oil of thyme 3 oz.

Another formula is the following: — Hard curd soap)
(made from good tallow 9 parts, olive oil i part) 100 oz.,:

* " Dingl. Polyt. J." cxxxv. 237.

136 SOAPS.

scented with oil of caraway i oz., oil of lavender J oz., and
oil of rosemary J oz.

Rose Windsor is the plain variety coloured with ver-
milion or iron oxide, and perfumed, after the soap has
been transferred to the frame, with essence of roses.

Violet Windsor* is composed of 50 parts of lard, 33 parts
of palm oil, and 17 parts of spermaceti, perfumed with
essence of Portugal and a little oil of cloves.

5°. French System.

The French have devised special machinery for the
manufacture of the finest kind of toilet soaps. The " stock "
soap, or basis, should be made from the purest materials.
Usually, it is prepared by the cold process.

The mode of procedure is as follows : —

i°. CUTTING. — The soap having been cut into bands by
the hand cutter (Fig. 30) is passed to the rotary cutter

FIG. 31.
FIG. 30.

BEYER'S hand cutter. BEYEII'S rotary cutter.

(Fig. 31), or to a EUTSCHMAN automatic soap-chipper
(Fig. 32), by which it is reduced to thin shavings. This
machine is usually placed in the drying-room, in order that

KICHARDSON and WATTS, "Technology," vol. i. pt. iii. p. 707.

TOILET, OR FANCY, SOAPS. 137

during the process the shavings may become somewhat
drier.

FIG. 32.

Automatic soap-chipper.

2°. CRUSHING AND GRINDING. — The dry shavings are now
ready to be placed, with the desired perfumes and colouring
matters, in the hopper of the crushing -mill, Fig. 33 or Fig. 34.

This machine is mounted on a frame cast in one piece,
and carries three or four granite rollers. The motion of

138 SOAPS.

the rollers draws the soap shavings between the first and
second rollers, which are so geared that the second re-
volves more quickly than the first, and the soap is thus not
only crushed, but also undergoes a rubbing action. The
increased speed of the second roller has the effect also of
passing the crushed material along so as to place it between

FIG. 33.

BEYER'S crushing-mill.

the second and third rollers, where it undergoes a second
crushing. The third roller, revolving at a still higher
speed than the second, causes the soap to be seized and
crushed again between the third and fourth rollers. The
soap paste is removed from the last roller by a steel
scraper, and returned to the hopper, from which it is again
passed through the mill. This triple crushing by the sue-

TOILET, OR FANCY, SOAPS.

139

cessive passing of the soap between the rollers is technically
called in France passe (passage). Each passage of 30 kilo-
grams (about 60 Ib.) occupies five minutes.

Fio. 34.

EUTSCHMAN'S crushing-mill.

Three or four passages, or more, are generally required
to effect perfect amalgamation of the mass, the exact
number depending on the nature of the materials. When
the workman judges that the operation is finished, he
presses a button, acting on two scrapers, and these fall

140

SOAPS.

in front of the fourth roller, and the separated ribbons
of soap are received in a small waggon, by which they are
conveyed to the plotting and squeezing machine (boudineuse-
peloteuse). In some factories, however, the crushing-mill
is so placed that the ribbons can be directly thrown from it
to the feeding-hopper of the plotting machine.

BEYER'S continuous plodding machine.

3°. PLOTTING or PLODDING. — The object of the plotting
machine is to compress the ribbons and shape them into
perfectly homogeneous and compact bars, and its use has
tended greatly to the development of the manufacture of
toilet soaps. A representation of this apparatus is given in.

TOILET, OR FANCY, SOAPS.

141

Figs. 35 and 36. In this machine, below the hopper, there
is a powerful screw propeller, conical in shape, and fitting
closely the conical barrel. Owing to this form, the ribbons

of soap, falling from the hopper upon the larger part of the
revolving screw, are forced towards the mouth of the barrel
with increasing pressure. The brass mouthpiece is fitted

142

SOAPS.

with gauge-plates for altering the size and shape of the bar
as it issues therefrom. These two machines are capable of
turning out 10,000 cakes of soap in one day.

In another form of plotting machine the soap is pressed
by means of a hydraulic rani through a cylinder, and
squirted through a mouthpiece of the required dimension
shape.

FIG. 37.

RUTSCHMAN'S cake-cutting machine.

4°. CUTTING INTO CAKES. — From the plotting machine
the bars are transferred to a cutting machine, worked either
by the foot (Fig. 37) or by steam, and cut into blocks or
<cakes of the desired size.

s°. STAMPING. — These cakes are afterwards moulded and

TOILET, OR FANCY, SOAPS. H3

stamped, either by a stamping press worked by hand or foot
or by steam (Fig. 38 and Figs. 20, 27, 28, 29, pp. 76, 120,

121, 122).

Fro. 38.

KUTSUIIMAN'S soap press.

By Dr. C. E-. A. WEIGHT'S patented process * a soap free
from uncombined non- volatile alkali may be produced under
the French system from stock soaps containing free alkali.

* English patent 7573, February 10, 1885.

J44 SOAPS.

A quantity of an ammoniacal salt (such as the chloride or
sulphate), equivalent to the average amount of free alkali
in the stock, is dissolved in the smallest possible quantity
of warm water and added to the shavings before their first
passage through the mill. During the successive grindings
the ammonia and ammonium carbonate formed from the
neutralization of the free alkali are practically entirely re-
moved by evaporation, which readily takes place from the
thin ribbons scraped off from the rollers.

The chief advantages of the milling process are that the
most delicate perfumes can be mixed with the soap without
loss, as there is but little heating during the operation,
and that as the cakes produced contain less water than
those formed by the re-melting process, they require a less
time in the drying-room before being ready for sale, and
will not afterwards shrink or lose weight.

CHAPTER IX.
MEDICINAL SOAPS.

DECHAN gives the following results obtained in his valuable
investigation into the character of the soaps of pharmacy :* —

" Generally speaking, the samples examined are to be
relied on for the quality and complete saponification of the
fat employed, though in a few instances the purity of the
oil might have been called in question. In almost every
case the combined alkali is in excess of the quantity required
to form the normal salt, and in several of the samples there
is a considerable percentage of free alkali. This is un-
fortunate, especially as regards the free alkali, because the
value of the soaps for many pharmaceutical purposes, such
as excipients for certain pill masses, bases for suppositories,
&c., depends to a considerable extent on the complete com-
bination of the alkali with the fat.

" Sapo Durus, B.P. — There is some difference of opinion
as to whether * hard soap ' is synonymous with ' white
Castile soap.' Mr. Squire says * the Sapo durus of the
Pharmacopeia refers without doubt to the white Castile
soap.' But if it is meant, as seems to be intended, that
foreign Castile soap only is referred to, then, with all defer-
ence to this authority, there is very considerable ' doubt '
in the matter. Some firms supply the same soap indis-

* " Pharmaceutical Journ." April 25, 1885.

146 SOAPS.

criminately, but others make a distinction, as will presently
be shown, and it would be well if we had some authoritative
declaration to guide us. For example, Nos. 2 and 1 1 were
supplied at the same time by one firm, and it is perfectly
evident that the soaps are quite distinct; No. i, on the
other hand, bears a much stronger resemblance to Nos. 10
and ii than it does to No. 2. The principal constituents,
olive oil and soda, are the same in both classes, so that the
main distinction between them, No. i excepted, is that
Sapo durus contains a higher percentage of fat, and con-
sequently it is of more value. "We may therefore quite
fairly infer that sample No. i is a specimen of Sapo castil.
alb., and if this much be allowed, then we can see a very
sharp distinction between the two classes of soaps ; Sapo
durus containing nearly 7 per cent, more fat than Sapo
castil. alb. This difference is certainly too much to allow to
accident, so it must be accounted for in some other way.
CHRISTISON in treating of these soaps says that they are
chiefly imported, especially from Spain, ' but of late years
hard olive soap has been manufactured in England' (' Dis-
pensatory/ p. 280); consequently, it appears quite possible
that there is another distinction between these two soaps,
apart from that shown by the analysis— viz., that Sapo
durus is of English manufacture, whereas Sapo castil. alb.
has always been recognized as a foreign product. Should
this be correct, then they are not one and the same, not-
withstanding Mr. Squire's statement to the contrary, and
it would evidently be of some value to have this authorita-
tively decided, because there can be no two opinions as to
their relative value as shown by the analysis. All the soaps
responded to the tests given by the B.P. with the exception
that none of them were entirely soluble either in water or
rectified spirits, the largest percentage of insoluble matter
being 1.8 in the case of No. i.

MEDICINAL SOAPS. 147

" Sapo Animalis. — The finest quality of this soap is made
from pure tallow which has undergone the process known
as ' rendering/ and this alone ought to be used for pharma-
ceutical purposes. The fat from which the specimens
examined had been manufactured was of a uniform and
good quality, which could not be said of some of the other
classes. With the exception of No. 7, all the samples con-
tained a larger percentage of uncombined alkali than did
those of Sapo durus, and on this account, even if no other
reason existed, ought not, under any circumstances, to be
preferred to the latter, which is of a decidedly milder type,
and therefore much better suited for those galenical pre-
parations in which soap is a necessary constituent.

" /Sapo Castil. Alb. — The analytical results of the different
specimens indicate that much care is bestowed on the
manufacture of this article, with the view evidently of pro-
ducing a soap containing as near as is practicable a uniform
percentage of fatty matter, the greatest variation in this
•direction being 2.4 per cent., which, considering the modus
operandi of soap manufacture, is exceptionally small. It is
also worthy of note that one sample (No. 9) did not contain
the slightest trace of uncombined alkali, being, in fact, the
only one of the twenty specimens examined which showed
absolute freedom from what must be considered a most
objectionable ingredient. The fact that this sample is of
•continental manufacture ought to have some meaning tc
British manufacturers, showing, as it does, that it is quite
possible to manufacture a perfectly neutral soap, whereas
the efforts of many home makers in this direction end in
utter failure. Like Sapo durus, Sajw castil. alb. answered
fairly well to the B.P. tests, and if the difference in the per-
centage of fat be taken into account, the latter can be quite
appropriately substituted for the former, and vice versa.

" Sapo Gastil. (Mottled). — This soap is decidedly of an.

Lri —

148 SOAPS.

inferior character as compared with Saj)o castil. alb. It
contains a larger proportion of free alkali, and the fat is
also much lower in quality. This ought, in my opinion, to*
prevent its being used for either Sapo durus or Sapo castiL
alb., for which it is sometimes substituted. The mottled
appearance of the soap was produced in some cases with
ultramarine, and in others with iron salts. The materials
added for the purpose of mottling in no way enhance the
value of the soap, but, if anything, have an opposite ten-
dency, and the fact that soap manufacturers should persist
in mottling the soap can only be explained by the demand for
such by a taste which may be characterized as uninformed
and antiquated.

" There seems to be a common impression that the mottled
Castile is better than the white, this opinion being founded'
probably on PEREIRA'S statement that the white soap is
purer than the mottled, ' but it is a weaker soap (i.e., it
contains more water).' It is possible that when this was
written the relative composition of the soaps may have
been different to what it is now, but it is remarkable that in
every case in the under-noted table [p. 150] the samples of
mottled soap gave higher .percentages of water than those
of the white. If it is meant that the white is weaker in
the sense of being less irritating, the contention might be
admitted ; but this is of course no advantage, so that the
mottled variety is in every respect decidedly inferior.

" There also seeins to be a common notion that soap con-
tains a very large percentage of water, one writer stating
recently that it contained 40 per cent, more or less. This
is quite true if it be applied only to the common scouring
soaps, but decidedly erroneous when the statement is made,
as in this case it was, with reference to the soaps under
consideration.

Mollis. — The percentage of free alkali in the-

MEDICINAL SOAPS. 149

samples of this soap is very remarkable, one sample con-
taining as much as 0.8 per cent. The quantity of combined
alkali in excess of that required to form the normal potassic
salt is also much greater than in that of the others, the
mean of the four samples examined being 4.25 per cent.
The composition of Sapo mollis is liable to vary to a much
greater extent than any of the other classes, and for this
reason the soap is not so much to be depended on. The
cause of this irregularity is mainly due to the process of
manufacture, which depends more on the operative in charge
of the work than is the case in the manufacture of hard
soaps.

" That something ought to be done to reduce the per-
centage of free alkali in soaps required for pharmaceutical
purposes will be readily admitted, and that soaps can be
produced which do not contain this irritating and corrosive
agent we have sufficient evidence in the results given in the
table [p. 150]. It remains with those who have a right to
speak in the matter to make it known that a soap con-
taining free alkali ought not to be used in pharmacy."

Aromatic Mouth Soap (ZALMON'S)*. — i Ib. of neutral
soap, prepared from fat of the best quality, is dissolved in
cold distilled water; about 3! oz. finely sifted cuttle-fish
bone are added to the solution, and the whole is evaporated
.at a gentle heat. "When the desired consistency is nearly
reached, add J drachm each of peppermint oil, sage oil,
virgin honey, and wine vinegar, or lemon oil. Mix the
whole quickly by stirring, and pour into suitable moulds
to cool. Colouring matter may be added as desired.

Aromatic Antiseptic Tooth Soap.f — Castile soap i Ib.,
pumice-stone in fine powder i oz., thymol 20 grains, oil
of wintergreen 30 drops.

* " Chemist and Druggist," 1880, p. 13. f Ibid. 1884, p. 73.

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MEDICINAL SOAPS. 151

Shave the soap into ribbons, beat it into a paste with a
little water, and add first the pumice-stone, and then the
thymol and oil of wintergreen dissolved in a small quantity
of alcohol.

Castor-oil Soap (for Linimentum Saponis Compositum).
— According to M. S. HAMMER,* this soap seems to answer
best for this liniment, and may be prepared by the follow-
ing process : —

Saponify 2 pints of castor oil with 6 oz. of caustic potash
and 2 pints of water by heating till a transparent mixture
is obtained ; then add a saturated solution of 8 oz. of
sodium chloride, stir until cool, allow to subside for a day,
decant the liquid portion, cut in pieces, and dry for use.

Chlorinated Soap (Sapo Colds Chlorinates). — Castile
soap in powder IT oz., chloride of lime (dry) i oz. Mix,
beat them to a mass with rectified spirit q.s., holding in
solution oil of verbena, or of ginger-grass, 5 oz. Lastly,
form the mass into flat tablets, and wrap in thin sheet
gutta-percha. Said to be well adapted for hospital use, for
removing stains from the skin, and for preventing infection
from contagious diseases.

Camphorated Sulphur Soap.t — 12 kilos, of cocoa-nut
oil, 6 kilos, of soda lye (38° B.), i kilo, of potassium sul-
phate dissolved in |- kilo, of water, and 160 grams of cam-
phor, which is to be dissolved in the melted cocoa-nut oil.

Gall Soap.t — i kilo, of galls is stirred in 25 kilos, of
melted cocoa-nut oil, and then saponified cold with. 227,- kilos,
of soda lye (38° B.). The soap is coloured with 3^0 grams
of ultramarine green, and perfumed with 75 grams lavender
oil and 75 grams cummin oil.

Iodine Soap.f — 10 kilos, cocoa-nut oil, 5 kilos, lye

* "Proc. Cal. Pharm. Soc." 1883, p. 50; "Year Book of Phar-
macy," 1883, p. 313.

f "Year Book of Pharmacy," 1883, p. 313.

152 SOAPS.

(38° B.), and i-J- kilo, of potassium iodide, dissolved in
^ kilo, of water.

Disinfecting Soap (JEYE'S Improved}. — Gas tar is dis-
tilled and the light oil rejected ; 16 parts of the heavier oil,
32 parts of cocoa-nut oil, and 16 parts of caustic soda at
35° B. are saponified in a jacketed pan, with or with-
out the addition of rosin, and sodium sulphate and car-
bonate. *

Liquid Soaps (KiNGZETT's).t — KINGZETT prepares liquid
soaps for employment as insecticides by dissolving rosin or
crude turpentine in alcohol, and saponifying with potash.
To this is added an alcoholic solution of a fatty acid soap
and various disinfectants. Or,J crude turpentine, or rosin
may be dissolved in " Sanitas " oil, or rosin spirit, or rosin
oil, and then saponified by caustic-alkali solution of sp. gr.

1.300. Camphor is added to insure a permanently liquid
product, and this may be medicated by addition of thymol,
&c. Or,§ petroleum spirit, or thymol, may be used instead

of, or in conjunction with, the " Sanitas " oil mentioned in
the last patent.

Mercurial Soaps. — i. Sapo Hydrargyri. — Dissolve 4 cz.

of mercury in the same weight of nitric acid without heat ;

melt in a porcelain basin, over a water-bath, 18 oz. of veal

suet, and add the solution, stirring the mixture till the

union is complete. To 5 oz. of this ointment add 2 oz. of

solution of caustic soda (sp. gr. 1.33) till a soap is formed

which is completely soluble in water.

2. Sapo Mercurialis. — Castile soap (in powder) 4 oz.,

corrosive sublimate i dr. dissolved in rectified spirit i oz. ;

beat to a uniform mass in a mortar.

* English patent 16,427, December 13, 1884.
t >, t» 3,894, March 26, 1885.

J ,, ,, 2,210, February 17, 1885.

§ „ ,, 3.855, March 25, 1885.

MEDICINAL SOAPS. 153

3. Sapo Hydrargyri Precipitati AIM (Sir H. MAHSH). —
Beat 12 oz. of white Windsor soap in a mortar, add
i drachm of rectified spirit, 2 drachms of white precipi-
tate, and 10 drops of otto of roses; beat the whole to a
uniform paste.

4. Sapo Hydrargyri Precipitati Rubri (Sir H. MARSH). —
White Windsor soap 2 oz., nitrate of mercury (levigated)
i drachm, otto of roses 6 or 8 drops, in rectified spirit
i to 2 drachms ; beat to a paste.

Soap Leaves. — These are made by passing continuous
paper sheets over rollers through a hot solution of soap,
the excess of soap attached to the surface being scraped off.
The paper then is conducted over drying cylinders to the
cutting machine.*

Tannin Soap. — 9 kilos, of cocoa-nut oil are saponified
with 4^ kilos, of soda lye, then 250 grams of tannin,
previously dissolved in alcohol, are put in, and the whole
mixed. The soap is perfumed with 30 grams Peru balsam,
10 grams cassia oil, and 10 grams oil of cloves.f

Tar Soap (Sapo Piceus). — Tar i part, liquor potassre
and soap (in shavings) of each 2 parts ; beat them together
till they unite. Action, stimulant, in psoriasis, lepra, &c.

Turpentine Soap (8apo Terelinthince ; STARKEY'S Soap).
• — Potassium bicarbonate, oil of turpentine, and Venice tur-
pentine, equal parts ; triturate together in a warm mortar,
with a little water, till they combine ; put the product into
paper moulds, and, in a few days, slice it, and preserve in
well-stoppered bottles.

Unna's Soaps. J — UNNA started his experiments by pre-

* KEITHOFFER and NEFFE, Vienna, German patent 23,195, June 6,
1882 ; " J. Soc. Chem. Ind." 1883, p. 543.

f "Year Book of Pharmacy," 1883, p. 313.

J " Edinburgh Medical Journ." October 1885 ; " Year Book of
Pharmacy," 1886, p. 282 ; " Pharm. Journ." xvi. 328.

154 SOAPS.

paring a normal soap of fixed composition, which could be
incorporated with various medicinal substances. Though,
theoretically, he considered that beef fat was the most per-
fect, still, practically, he found that an advantage was
gained by adding i part of olive oil to 8 parts of beef fat.
The alkali consisted of 2 parts of soda to I of potash, this-
combination being less apt to blister when medicinal sub-
stances were added to the soap. Cocoa-nut oil, though pro-
ducing a soap which lathers well, was found to make the
skin dry after continued use. Even a neutral soap, when
constantly used, tends, according to UNNA, to produce an
unpleasant roughness, from removing too completely the
natural oiliness of the skin. He, therefore, leaves the soap
over-fatty, that is, besides the fat necessary for perfect
saponification, an excess amounting to 3 or 4 per cent, is
added. Any secondary addition of glycerin or vaseline he
entirely rejects. This soap he terms over-fatty normal soap
(iiber fettete grund Seife). It may be used as an ordinary
washing soap in all forms of inflammatory skin diseases
where ordinary soap is forbidden, as in eczema, erythema,
and for skins poor in fat with a tendency to dryness ; also
as a soap for healthy people whose occupation compels them
to wash frequently in the course of the day. The compo-
sition of such soap is : —

1 6 parts best ox fat „ . . . 59.3

2 ,, olive oil . . . . . 7.4
6 „ soda lye (38° B.) . . . 22.2

3 „ potash lye „ . . . .11.1

27 100.0

In this soap about 4 per cent, of oil remains unsaponified.
It is of a yellowish-white colour, of a waxy consistence, and
quite permanent. It forms an exceedingly good soap for
children, and, if rubbed on the hands and wiped off again in
a few minutes with a dry towel, it leaves the hands smooth,

MEDICINAL SOAPS. 155

and little liable to be injuriously affected by damp, cold, or
long-continued contact with carbolic acid.

Over-fatty Marble Soap consists of equal parts of the
foregoing, and the finest powdered marble. It will be found
useful in thinning down the horny layer in acne. It thus
replaces pumice-stone and sand soap, and, while the pow-
dered marble rubs off the scales or the thickened epider-
mis, the over-fatty normal soap leaves the polished surface
smooth and normally unctuous.

Over-fatty Ichthyol Soap* — This has its special value
in the treatment of various forms of rosacea, both in the
congestive and cyanotic forms, and can be advantageously
employed with hot water. A stronger effect is produced by
leaving the soapy lather to dry on.

Wych-hazel Soap.t — The juice of the plant Hama-
tnelis virginica, or common wych-hazel, is mixed with soap,
and with various compounds for toilet purposes which con-
tain soap. Such compounds are said to be beneficial in the
case of bruises and lacerations of the skin.

* IchtJiyol, or fish oil, first prepared by SCHROTER, is the distil-
lation product of a peculiar bituminous sulphurous mineral ob-
tained from deposits of fossil fish. According to BAUMANN, sodium
ichthyosulphate has the composition represented by the formula

f DIMBLEBY, English patent 11,305, August 15, 1884; "J. Soc.
Chem. Ind." 1885, p. 459.

CHAPTER X.

OLEIC-ACID, RED OB BROWN OIL, SOAPS-
SOFT SOAP— INDUSTRIAL SOAPS.

Oleic-acid or Red Oil Soaps.

OLETC-ACID, red or brown oil, is a bye-product of the candle
manufacture, and, being already separated from glycerin, it
readily enters into combination with alkalies, either caustic
or carbonated.

Morfit's Process. — The red oil, or other fatty acid, is
poured into an open pan, with a fire beneath, to one-third
of the depth of the vessel, in which it is agitated and heated
by the patentee's steam- twirl* If it is desired to make a
^grade of soap lower than toilet soap, rosin, in the proportion
of 5 per cent, of the acid and upwards, is added in small
lumps as soon as the oil has become hot. When, after con-
tinued heating and stirring, the rosin is entirely dissolved,
finely powdered carbonated alkali is added in quantity pro-
portionate to the homogeneous mixture of fat and rosin,
while the twirl is kept slowly revolving. When all the alkali
is in, and the swelling-up caused by the escape of carbonic

* This is a sort of rotatory paddle fixed inside the copper, tubu-
lar, and perforated at intervals. It is connected by means of a
hollow spindle with the boiler, so that steam can be admitted
through it at will. Thus heating and mixing are effected simul-
taneously.

OLEIC-ACID SOAPS. 157

acid has subsided, the paste begins to thicken, and soon
assumes the condition of soap. It is then removed to the-
frames, and left to settle. For neutral soaps, the quantity
of carbonated alkali should only slightly exceed the proper
equivalent proportion, determined by calculation from the-
combining number of the fat acid which constitutes the-
" stock." For strong soaps the quantity of alkali may be
increased.

The advantages claimed for the preparation of soaps by
MORFIT'S process are — ( i ) As the relative proportions of the
ingredients are adjusted at the beginning of the operation,
there is no waste lye or any other residue. (2) The soap
is said to come out promptly, and in greater perfection than
can be readily obtained by the usual method of boiling upon
caustic lye. (3) The product is always uniform in appear-
ance and composition, and does not shrink or deteriorate by
time and atmospheric influence.

Another way of preparing this soap is the following: —
1300 Ib. of soda lye of 18° B. are boiled in the copper, and
to it are gradually added, with constant stirring, 1000 Ib.
of red oil. The oil is rapidly taken up by the lye, and there
is considerable intumescence, which has to be kept down
by uninterrupted stirring. As long as the paste continues
strongly caustic it must have new additions of oil till only
slight alkalinity remains. If, on the other hand, after cooling
for two or three hours in the copper, there is a deficiency of
alkali, it must be heated with 50 or 60 Ib. more lye. The
fire is then extinguished, and the paste, after an interval
of about twenty-four hours, is removed to the frames, which
should be very shallow, as this soap sets slowly.

CARPENTER * describes MORFIT'S method for the prepara-
tion of soap from fatty acids as follows : —

* SPON'S " Encyclopaedia," v. 1771.

158 SOAPS.

The soda is used in the form of a refined carbonated ash
at 52°, every 100 Ib. being dissolved in 160 Ib. of water in
a lead-lined vat, and the solution allowed to settle previous
to use. The store-tanks of this, and of the fatty acids
employed, are connected with small gauge-tanks or measur-
ing tubes for the purpose of obtaining uniformity of results
by the use of exact quantities in every operation.

For the delivery of the soda solutions into the soap-pan a
special feeder is provided, so that the flow of liquid may be
regulated at discretion ; a perforated rose-spout may be
advantageously placed under the exit pipe.

The soap-pan is jacketed and furnished with a stirrer, and
the steam is either superheated, or used at a pressure of
75-80 Ib. The pan has a movable curb above it, so as to
give room for the increase of bulk caused by the liberated
carbonic acid. The curb, when required, can be drawn
aside on a railway.

In making soap with this apparatus, 1000 Ib. of oil are
run into the pan, with the curb in its place, and heated to
280-320° F. (138-160° C.) according to its quality. At
this point, for a neutral soap, 190 Ib. of soda ash, or, for a
strong soap, 210-225 Ib., dissolved in the proper quantity of
water, at 212° F. (100° C.), is let into the pan at such a speed
that the time occupied is not less than six nor more than
twelve minutes. The whole is kept well stirred, and swells
up enormously ; but, in five minutes after the last portions
of alkali have been added, the mass subsides, aiid, in fifteen,
minutes more, changes from a spongy to a clear, soft,
brilliant, homogeneous paste. The curb is then removed,
and, in about an hour, 100 Ib. of boiling water are let in
from the rose-spout of the soda-feeder, and the whole is
again well stirred. If it is desired to add sodium silicate, or
any other substance, it is introduced at this stage, after
which the soap is transferred to the cooling frames, and a

SOFT SOAP. 159

fresh batch is proceeded with. Soap thus made has the
following composition : —

Water 27.50 per cent.

Oleic acid .... 65.00 „
Soda . . . 6.70 to 7.50 „

When rosin is used, it should be added to the oil while the
latter is being heated, or the rosin soap may be made in a
separate pan provided with a MORFIT'S steam-twirl: 1200 Ib.
rosin and 2200 Ib. caustic lyes at 11° B. are boiled together,
and the thin jelly so produced is transferred in suitable
quantities to other pans. This soap contains : —

Water 37.7 per cent.

Rosin 54.5 „

Soda . . . . 7.8 „

According to MORFIT the refined ash of 52°, prepared by
the Jarrow Company, Newcastle-on-Tyne, has the following
composition : —

Water i.oo

Sand and silica traces

Sodium chloride 2.84

,, sulphate ..... 8.04

carbonate . . . 88.66

Total . . 100.54

Soft Soap.

The article which is known as soft soap is not, strictly
speaking, a true soap, but rather a more or less impure
solution of potash soap in caustic lye, forming at ordinary
temperatures a transparent smeary jelly.

Soft soap is used to some extent for washing coarse linen,
but it is of far greater importance, as an indispensable and
powerful detergent, in linen-bleaching works.

The fatty materials employed in this country for making

160 SOAPS.

soft soaps are whale oil, seal oil, linseed oil, and tallow ; on
the Continent, the drying oils, hemp, linseed, sesame,
camelina, and poppy, and the non-drying oils, rape, train,
<fcc. As the first group produce a softer article, it is cus-
tomary to mix the oils in different proportions according
to the time of year, employing more of the drying oils in
winter and of the non-drying oils in summer.

B/osin may be introduced, in fine powder, up to Jrd of the
weight of the fatty matters.

In the preparation of the soap, in some works, a portion
of the oil is first introduced and heated. Then weak potash
lyes, marking from 9° to 11° B., are added; moderate heat
is kept up, more oil and lye being alternately added till the
whole of the charge has been introduced. Some makers
add the whole of the fat at once together with a portion of
the lye, and the remainder of the lye after some hours.
Gentle ebullition, with great care to prevent boiling over,
is continued till the saponification is judged complete. The
boiling gradually becomes quieter, the frothy mass subsides,
the paste grows more transparent, becomes thicker, and a
thick, sticky fluid falls in streaks from the stirrers. As
soon as these characters are apparent, stronger lye is gra-
dually added for the purpose of clarification. If a trans-
parent appearance is not readily produced, it is requisite to
add some very strong lye. "When the combination is perfect,
the clear and transparent paste should be free from clots or
granules, and there should be no acrid taste. To ascertain
if this is the case, a small sample, free from scum, is taken
out from the middle of the pan and cooled. If it should
neither be of proper consistence nor free from opacity, the
boiling is continued, and re-tested in the same way at
intervals until the soap is properly finished.

In the cooling of these small samples, peculiar phenomena
are noticed, which afford good means of judging of the

SOFT SOAP. 161

quality of the soap. When there is formed round the little
patch, dropped on to a piece of clean glass, an opaque zone,
a fraction of an inch broad, this is taken as indicating com-
plete saponification, and is called strength. "When this ring
is absent, the soap is said to want strength. When the
zone, after being distinctly seen, soon disappears, the soap
is said to have false strength.

Towards the end of the boiling, the soap becomes thicker,
the colour darkens, and there is less frothing. When
the bubbles become so large as to overlap, they resemble
films or lamellae, and soap-boilers term such appearance
lamination. A peculiar noise at this point is heard, and
it is said the soap talks. If, on testing a portion, no opaque
zone, or only a slight one, appears after cooling, it may be
concluded that the proper proportions have been attained.

When the tests are satisfactory to the experienced ope-
rator, the fire is extinguished, or the steam turned off, the
soap is left for some time longer to cool, and is then packed
in small casks for use. The cooling is sometimes aided by
the introduction of a quantity of cold soap.

/Scotch Method. — 273 gallons of whale or cod oil and
4 cwt. of tallow are put into the soap-pan, with 250 gallons
of lye, made from American potash, of such strength that
i gallon contains 6600 grains of real potash. Heat being
applied, the mixture froths very much as it approaches the
boiling temperature, but is prevented from boiling over by
beating down on the surface within the iron curb which
surmounts the caldron. Should it soon subside into a
doughy-looking paste, the lye has been too strong. Its
proper appearance is that of a thin glue. About 42 gallons
of a stronger lye, containing about 8700 grains of potash
per gallon, are now introduced, and, after a short interval,
another 42 gallons; and thus successively till nearly 600
such gallons have been added to the whole. After suitable

162 SOAPS.

boiling to saponify the fats, the proper quality of soap will
be obtained, amounting in quantity from the above mate-
rials to 100 firkins of 64 Ib. each.*

Russian Method. — According to KURRER, a lye containing
three-fourths caustic potash and one-fourth potassium car-
bonate marking 10° B. is added to the linseed, rape, or
hemp-seed oil in the boiler. An equal quantity of the same
lye is placed in a cistern by the side of the boiler, and is
allowed to flow uninterruptedly in a minute stream into the
boiler, so that the state of ebullition is not checked. The
process is judged complete when the soap flows from the
stirrer as a clear slime which can be drawn out in threads
between the fingers.

The results by this method are uncertain, and the product
is never uniform.

Gentele's Method. — GENTELE found that the potash in soft
soaps may be partially replaced by soda without any dis-
advantage. The product contains a little more water than
ordinary soft soap. The best proportions are said to be
i part of soda to 4 parts of potash lye, and the lyes should
be free from salt and other saline impurities, which prevent
the clarifying of the soap. A mixture of 100 Ib. of red
oil, 50 Ib. of tallow, and 3750 Ib. of hemp-seed oil makes
a good stock for this soap.

Soft soaps are more caustic than hard soaps, and contain
whatever impurities may be present in the materials. The
white granular masses in soft soaps are due to potassium
stearate, and are sometimes imitated by the introduction of
starch.

* URE'S " Dictionary of Arts," &c., iii. 702.

INDUSTRIAL SOAPS. 163

Industrial Soaps.

" Fulling " Soap, or soap for cleansing and scouring
woollen fabrics, is a soft soap of the composition* —

i. ii.

Fatty acids . . . 50.0 ... 40.0

Potash . . . .11.5 ... 9-5

Water . . . . 38.5 ... 50.5

It should contain a slight excess of alkali, but no rosin
{which hardens the fabrics), starch, or silicate.

Or,")" a brown-oil soap, prepared by MORFIT'S process,
which should have a stiff body and be slightly strong in
alkali, may be used. Its solution in boiling water must cool
to a jelly in a reasonably short time. Its suitability in this
respect may be ascertained by dissolving, with the aid of
heat, i oz. of the sample in 7|- oz. of water, and then add-
ing cold water up to 16 fluid oz. This should form a jelly
within half an hour. Such a soap, when freshly prepared,
has, according to MORFIT, the following composition : —

Fat (melting point 84° F.) . . . 65.00

Combined soda 6.50

Other salts 1.40

Water 27.10

100.00

Another formula that has been proposed for soap for
•cleansing woollen fabrics J is : — i part of borax and 32 parts
of Castile soap incorporated with water into a thick paste,
to which a fragrant essence may be added.

Ox-gall Soap. — The following method gives a satis-

* RICHARDSON and WATTS, " Technology," vol. i. pt. iii. p. 693 ;
KINGZETT'S "Alkali Trade," p. 175.

f MORFITT'S " Practical Treatise on Soaps," p. 196.
J M. S. GOSLING, English patent 5998, May 15, 1885.

M 2

1 64 SOAPS.

factory article:* — Mix together ij kilo, ox-gall with 25
kilos, melted cocoa-nut oil. Saponify this mixture by the
cold process with 12 J kilos, caustic-soda lye of 38° B. The
soap may be dyed by the addition of 850 grams of ultra-
marine, and, if desired, perfumed with a mixture of 75
grams of lavender oil and 75 grams of caraway-seed oiL
Ox-gall soap is useful for scouring woollen goods.

Soaps for Calico Printing and Dyeing. — Soaps from
tallow, palm or f>live oil are generally employed for calico
printing and dyeing, olive-oil soaps being sometimes pre-
ferred for Turkey-red dyeing. A good soap for these in-
dustries must be as neutral as possible, and thoroughly
saponified.

When soaps of the alkalies are used as mordants in con-
junction with alum, or tin or lead compounds, there is a
combination of alumina, tin, or lead with the fatty acids of
the soap, and an insoluble metallic soap is deposited on the
fibre.

According to 0. SCHEURER^ a soap for brightening colours-
such as alizarin, or garancin, should, first of all, produce a
perfectly white ground, upon which the colour then appears-.
much more brilliant, and, in the second place, it should not
attack the colour itself. On comparing, from this point of
view, the various soaps occurring in commerce, the Mar-
seilles soap was found to be the best, although the reason
for this superiority is not, at first, obvious. A soap which
attacked the colours used to be regarded as too alkaline^
but on analysis it was found to contain no more alkali than
the best soaps. It was especially the oleic-acid soaps which
exhibited this injurious alkalinity — attacking all shades of
colour. This behaviour is attributed by SCHEURER to the

* " J. Soc. Chem. Incl" 1882, p. 154.

f "Bulletin de Mulhouse," 1882, p. 142; "J. Soc. Chem. IncV
1883, p. 286.

INDUSTRIAL SOAPS. 165

fact that many so-called alkaline soaps made with oleic acid
simply contain both free oleic acid and free alkali, because
the saponification has not been complete. Such soaps
may be perfected by continuing the boiling. It should be
remembered that the combination of the acid and soda re-
quires a considerable time — two kinds of soap, an acid soap
and a basic one, seem to be produced at the beginning of
the process, and these gradually unite to form a neutral
soap.* The reaction can be hastened either by increasing
the temperature or the pressure; thus, at a pressure of 1.5
atmosphere SCHEURER found that a better soap is obtained
in two hours than in twelve hours under ordinary pressure.
A soap manufactured by DAUMAS D'ALLEON, of Marseilles,
is recommended as the type of that best suited for dyeing
and printing purposes. It has the following composition : —

Fatty acids 55

/-i x- -I ^.T ^N , (or Q.IOO parts Na.,0

Caustic soda (Na20) . . . 6 | to *oo p^rts of f a2t

Water 39

Total . .100

The following method is said to be successfully used at
the Zawierciers Works for the preparation of a soap to be
used in dyeing and printing : — About 360 litres of water
.and 69 kilos, of lye at 36° B. are boiled up together, and
140 kilos, of oleic acid added with constant stirring till a
uniform mixture is obtained ; 3120 litres of water are then
added, and the mixture is well stirred till a clear soap solu-
tion results.

"When the above proportions are used, the oleic acid is
sometimes found to be in excess, and some more soda must
then be added. To prevent this, a little more soda should
be added at the beginning, f

* See also p. 53.

•f " Dingl. Polyt. Jour." 247, 12 ; " J. Soc. Chem. Ind." 1883, p. 286.

1 66 SOAPS.

Soap for Silk Throwsters.* — This should be the best
curd soap of the usual processes — white, and free from-
odour.

Soap for Silk Dyers. — The soap suitable for stripping
and boiling off gum from silk is a brown-oil soap,* which
should cleanse readily without injury to the silk, and be-
easily rinsed out. It is usual to add to the soap a propor-
tion of sodium sulphate.

In the North of Europe f soft potash soaps, generally
made from linseed oil, are used ; in the South, hard soda
soaps made from olive and other oils are preferred. Of late
years, soaps made from oleic acid have been increasingly
used. In general, those which are made from oleic acid
and linseed oil wash off best ; next, those from olive oil and
suet, &c. Palm-oil soap does not rinse off so well. For
scouring silk to be dyed, oleic-acid soap is most suitable, but
for those destined to remain white a good olive-oil soap is
preferable.

According to CALVERT, the soft soaps usually made for
dyers' use are not indiscriminately applicable to all colours.
To produce the maximum effect in brightening the shade,
the soap should be composed of —

For Madder Colours.

Purples. Pinks.

Fatty acids . . . 60.4 ... 59-23

Soda .... 5.6 ... 6.77

Water .... 34.0 ... 34.00

100.0 ... 100.00

Soap for Removing Stains. J — 22 Ib. of the best white
soap are reduced to thin shavings, and placed in a boiler
together with water 8| Ib. and ox-gall 13^ Ib. Cover up,

* MOBFIT.

f SPON'S " Encyclopaedia, " ii. 519.

j " Year Book of Pharmacy," 1885, p. 286.

INDUSTRIAL SOAPS. 167

and allow to remain at rest all night. In the morning heat
gently, and regulate so that the soap may dissolve without
stirring. When the whole is homogeneous and dows
smoothly, part of the water having been vaporized, add
turpentine 9 oz. and benzine (best clear) 7| oz. Mix
well, and, while still in the fused state, colour with ultra-
marine, add ammonia, pour jiito moulds, and stand for a
few days before using. The product is said to act ad-
mirably. /

Another formula-^ which requires more skill than the
former to prevent the soap coming out unevenly, is the
following: — Cocoa-nut oil 27.5 lb., tallow 2.2 lb., soap-
stone 4.4 lb., caustic-soda lye (sp.gr. 1.349) 15.4 lb., ox-
gall 0.6 lb., turpentine 0.3 lb., benzine o.i lb., brilliant
green o.i lb., ultramarine green 0.05 lb. Melt the fat,,
add the soapstone and colour, cool to 68° F. (20° C.), and
then add the solution of soda. When all is well united and
mixed, add very gradually the gall, continuing the agita-
tion, without intermission, for some time after all has been
added. Should any separation take place, cover the boiler
for a few seconds, and, if this does not help, fire up again,
and continue stirring. Lastly, add the turpentine and
benzine. Pour into moulds, and stand before using. This,
preparation, when properly applied with a brush, is said to
remove the most refractory stains without injury to the
cloth.

CHAPTER XI.
VARIOUS SOAPS AND SOAP POWDERS.

C. D. Abel's Process.* — This process aims at the pro-
duction of a hard soap which shall be practically almost
completely freed from the lyes, and shall contain much less
salt than ordinary curd soap, while at the same time a
much harder and more neutral product is obtained, contain-
ing also less water (from 20 to 25 per cent.) than that ob-
tained in the ordinary way. The soap, separated by salt as
usual, and before its separation from the lye by complete
cooling has taken place, is introduced into a centrifugal
machine driven at a high speed, and is subjected while hot
to centrifugal action for from four to at most twenty
minutes. By this means the separation of cocoa-nut-oil
soap can be perfectly effected.

Cold-water Soap. — This is a recent make of soap which,
as CARPENTER states,")" was at first made from very soft fatty
materials, but containing a very small amount of water. It
may also be made by drying "neat-soap," fitted in the
ordinary way, till about one-third of its water has been
driven off. Sometimes the term is applied to heavily
watered soaps. Potassium and sodium carbonates are fre-
quently added to increase the lathering property.

* English patent 6,472, April 17, 1884; "J. Soc. Chem. Ind."
1885, p. 226. f " Soap, Candles, &c.," p. 195.

VARIOUS SO APS. AND SOAP POWDERS. 169

The following is the composition of a genuine cold-water
soap (CARPENTER) : —

Fatty acids . , , . ,70.2
Soda — as soap ..... 7.3

„ in other forms . . .1.8
Silica ...... 1.6

Neutral salts ..... 0.4

Water . . . . . . 22.0

Total .... 103.3

Eichbaum's Soap. — In order to make a soap from
strongly smelling fish fats, F. EICHBAUM* takes 400 kilos.
of the fat, 25 kilos, raw palm oil, 250 kilos, lye of 12° B.,
and warms up. A further similar amount of lye of 15° B.
is added, and the thoroughly mixed mass allowed to boil
till clear and free from scum, more lye being added when
necessary. The mass is then poured in a thin stream
through 20° lye, 50 kilos, powdered rosin are added
gradually, and then 40 kilos, lye of 20°, and the mass
boiled. "When ready, the soap is salted in the ordinary
way. The addition of the rosin is said to lessen the fishy
smell considerably.

Kottula's Compact Neutral Soap.f — This soap is pre-
pared by combining any of the usual fats or oils with con-
centrated soda lyes and lime liquor. The soda lye is con-
centrated to about 28° B., and purified by boiling for half
an hour with alum, in the proportion of 4 to 4^ Ib. to every
cwt. of lye. The vessel is then removed from the fire,
alum again added, in the proportion of about 2 to 2J- Ib.
to each cwt. of lye, and the liquid is stirred till the alum
dissolves, after which the vessel is covered, and the whole
is left to settle and become clear. The lime liquor is pre-

* " J. Soc. Chem. Ind." 1886, p. 495.

f KICHJLKDSON and WATTS, "Technology," vol. i. pt. iii. p. 721.

170 SOAPS.

pared by combining water with lime, and then adding to
each cwt. of lime liquor about i| to if Ib. of sal ammoniac.
The liquid is boiled for about half an hour, and then allowed
to settle and become clear ; or the sal ammoniac is added to
the lime liquor while hot, and stirred for about half an
hour.

Ten tons of fatty matter, with or without rosin, 9 tons
of lye prepared as above, and 13 tons of lime liquor will
produce a superior compact neutral soap, which may be
coloured, mottled, or perfumed by the usual processes.

Kottula's Hand or Skin Soap. — The fatty matters are
mixed with highly concentrated soda lyes purified with a
certain quantity of alum and sal ammoniac, whereby a
neutral soap is said to be obtained cheaper and better than
by any other process.

The mode of procedure is thus described : — " I prepare
the highly concentrated lyes by boiling until they reach,
say, about 30° to 33° B., add about 5 Ib. of alum to each cwt.
of lye, and boil together for about half an hour. I remove
the lyes and alum from the heat, and add to each cwt. i Ib.
of sal ammoniac, stir for half an hour, cover, and allow the
mass to settle and become perfectly clear. To obtain the
lyes stronger than 33°, I make a second addition of alum,
but in smaller proportion. To obtain lyes of 42°, I make
a third addition of alum, and then add the sal ammoniac.
I melt a quantity of any fatty matter used in soap-making,
and, while still hot, stir, and add the lyes, prepared as before
described, say, to every 100 Ib. of fatty matter, about 100 Ib.
of 30° B., or 90 Ib. of 33° B., or 80 Ib. of 36° B., or 70 Ib.
of 39° B., or 60 Ib. of 42° B. ; continue to agitate the mass
till it becomes thick, and when thick it can be transferred
to the frames. After the soap is finished, it may be coloured,
mottled, or perfumed in the usual way."

VARIOUS SOAPS AND SOAP POWDERS. 171

Preparation of Soap in Small Quantities.* — The

Greenbank Alkali Company, of St. Helens, Lancashire,
prepare a refined 98 per cent, caustic soda in a fine powder,
and pack it in cans holding from 10 Ib. to 4 cwt. This
powdered article does not deliquesce or melt away like the
ordinary solid caustic soda, and any quantity may be taken
out as desired, and the remainder will not deteriorate, even
if the package be left open for some 'days. No boiling
pans are required, and it is perfectly easy to make a few
pounds of soap at a time with this alkali. The following
method, if exactly followed, will, it is claimed, always suc-
ceed : —

1. Take exactly 10 Ib. of double refined 98 per cent,
caustic-soda powder (Greenbank), put it into any can or
jar with 4^ gallons of water, stir it once or twice, when it
will speedily dissolve and become quite hot. Let it stand
until the lye thus made is cold.

2. Weigh out, and place in any convenient vessel for
mixing, 75 Ib. of clean grease, tallow, or oil (not mineral
oil). If grease or tallow be used, melt it slowly over a fire
until it is liquid, and of a temperature not over 100° F. If
oil be used, no heating is required.

3. Pour the lye, slowly into the melted fat, or oil, in a
small stream continuously, at the same time stirring with a
flat wooden stirrer about 3 inches broad. Continue gentle
stirring until the lye and fat are thoroughly combined and
appear of the consistence of honey. Do not stir too long^
or the mixture will separate again. The time required
varies somewhat with the weather, and the kind of tallow,
grease, or oil used j from fifteen to twenty minutes is gene-
rally sufficient.

* W. J. MENZIES, " Chemist and Druggist," 1880, p. 339.

172 SOAPS.

4. "When the mixing is completed, pour off the liquid
soap into any sufficiently large square box for a mould,
previously damping the sides with water so as to prevent
the soap sticking. Wrap up the box well with old blankets,
or, better still, leave it in a warm place until the next day,
when the box will contain a block of 130 Ib. of soap, which
can afterwards be cut up with a wire.

If the grease or tallow be not clean, or contain salt, it
must be rendered, or purified, by boiling with water, so as
to throw out the impurities. The presence of salt would
.spoil the operation entirely, but discoloured or rancid fat
is quite admissible.

If the soap turn out streaky and uneven, it has not
been thoroughly mixed. If very sharp to the taste, too
much soda has been taken; if soft, mild, and greasy,
too little. In either case it must be thrown into a
pan and brought to a boil with a little more wrater.
In the first case, boiling is all that is necessary; in
the others, a little more oil or a little more soda must be
added.

Any smaller quantity of soap than the above may be
made by taking the ingredients in smaller proportions, but
it is not advisable to make more than double the quantity
prescribed, as it is difficult to work more by hand. By
working successive batches, however, a person could turn
out 2 tons of soap in a day simply with apparatus obtain-
able in any household.

By adding a few drops of an essential oil just when the
mixing is complete, a toilet soap is produced. Oil of
mirbane (artificial almond oil) is the cheapest, but the
perfume is not nearly so pleasant as real almond oil,
citronella, or oil of cloves. When made with clean grease,
or tallow, or light-coloured oil, the soap produced is quite
white.

VARIOUS SOAPS AND SOAP POWDERS. 173

Sand Soap. — C. ROTH* recommends the following
method to prepare a good sand soap : —

100 Ib. of cocoa-nut oil are saponified with about 200 Ib.
of lye at 20° B. The soap is then hardened by the addition
of about 8 Ib. of salt dissolved in water to a density of
15° B., with the addition of 6 to 8 Ib. of soda ash. The
mixture is now covered up and the foam allowed to subside.
After standing five or six hours the foam is skimmed off,
and from 100 to 150 Ib. of dry sifted sand is thoroughly
crutched into the mass, and the crutching is continued till
the whole is cool. The soap is very firm and hard.

The soap is especially suited for the use of workmen en-
gaged in rough and dirty avocations. If desired, it may be
perfumed by the addition of 100 grams each of the essential
oils of lavender, thyme, and coriander.

Sodium Aluminate Soap. — The Pennsylvania Salt
Manufacturing Co. issue with their boxes of Natrona refined
saponifier (see p. 32), the following directions for making
soap without using scales, weights, or measures : — " Cut out
one end of this box, empty its contents into a pan, fill the box
three times with cold water, and pour it on the saponifier,
stirring until the latter is all dissolved. Into another pan
introduce as much rendered grease or fat as will fill the
same box five times. Now pour the dissolved saponifier
into the rendered fat, and stir for a few minutes until
thoroughly mixed. Let the whole stand till next day. Cut
into small pieces, and pour in two more boxes of water. Heat
and stir till the soap is all dissolved, and free from lumps.
Remove the heat, and when cool cut into bars or cakes.

" In very cold weather the water should be warmed a
little. The rendered grease should be about as thick as
honey, and not very hot."

* " Seifensieder Zeitung," 1884, p. xxi.

174 SOAPS.

Soap Powders.*

Borax Soap Powder. — Curd soap in powder 5 parts,
soda ash 3 parts, sodium silicate 2 parts, borax (crude) i part.

Each ingredient must be first thoroughly dried, and all
mixed together by sieving.

London Soap Powder. — Yellow soap 6 parts, soda
crystals 3 parts, pearl ash ij part, sodium sulphate ij
part, palm oil (bleached) i part.

These ingredients are mixed as well as possible without
any water, spread out to dry, and then ground into coarse
powder. The palm oil imparts an agreeable odour.

Pearl Soap Powder. — Curd soap (powdered) 4 parts,
sal soda (crude sodium carbonate) 3 parts, sodium silicate
2 parts.

Dried as much as possible, and intimately mixed.

Soap Extract. — Soap 14.3 parts, anhydrous soda 30
parts, and water 55 parts. Manufactured from crystallized
soda and soda soap.f

Washing Powder. — A powdery mixture of 90 parts,
effloresced soda with 10 parts of sodium hyposulphite and
2 parts of borax, f

Wool-washing Composition. — A mixture of 35 parts
of dried soda, 10 parts of pow-dered soap, and 10 parts of
sal ammoniac.f

Universal Washing Powder. — Sodium silicate, with a
small percentage of soap and starch powder. f

* " Chemist and Druggist," 1884, p. 73.
f Ibid. 1879, p. 243. .

CHAPTER XII.

RECOVERY OP GLYCERIN PROM
SPENT LYES.

Spent Lyes contain variable quantities of water, glycerin,
sodium chloride, sodium sulphate, sodium carbonate, caustic
soda, and small quantities of albuminous, resinous, and
soapy matters.

The glycerin was formerly wasted, but of late years great
attention has been devoted to its recovery, and many pro-
cesses for that purpose have been patented.

KINGZETT, in a valuable paper on this subject,* classes
the various processes as designed to effect the following
objects : —

i°. To remove, or destroy, albuminous or soapy matters,
together with any residual soap in the spent lyes.

2°, To facilitate the removal of the salt, either by employ-
ing means to diminish the solubility of the sodium chloride,
in cases where that substance is used, or to substitute
another which may be more readily and profitably removed.

3°. To economize the cost of concentrating the lyes to
that point at which the glycerin may be at once employed
for certain purposes in its then crude condition, or still
further purified by distillation.

* " J. Soc. Chem. Ind." 1882, p. 78.

1 76 SOAPS.

The following are some of the methods by which the
separation of glycerin has been attempted : —

I. Allan's Method. — Neutralize with any ordinary
mineral acid. After settling, add alum and chloride of limer
or pyroligneous acid, and stir thoroughly, or, before addi-
tion of the above, evaporate to the salting point. Distil
with superheated steam in an apparatus furnished with an
exit pipe for the removal of salt as it accumulates.

II. Allen and Nickels' Method.—" Lancashire lyes,"
in addition to the impurities already mentioned, contain
sulphides, hyposulphites, cyanides, ferrocyanides, sulpho-
cyanides, &c., from the custom of saponifying with causti-
cized Uack-ash liquor instead of by caustic soda. These
impurities make the recovery of glycerin in a satisfactory
condition from such lyes a very difficult operation. A. H.
ALLEN, of Sheffield, and B. NICKELS, London, have re-
cently, however, patented a process* which promises to
overcome this difficulty. The process depends upon the
factf that, when a solution of a copper salt (cuprous or
cupric) is added to soap lyes previously rendered neutral
or faintly acid, the sulphocyanides are wholly precipitated,
together with any sulphides, cyanides, ferrocyanides, or
silicates, and also with albuminous, resinous, fatty, colour-
ing, and other organic matters. The precipitate settles
with great facility, and the filtered liquid is obtained nearly
colourless. The copper is recovered from the precipitate
by roasting and treatment with sulphuric acid.

According to ALLEN, the following equation expresses the
main reaction which occurs in the removal of the sulpho-
cyanides by a cupric salt : —

* English patent 11,069, August 31, 1886.
f ALLEN, " J. Soc. Chem. Ind." 1887, p. 89.

GL YCERIN FROM SPENT L YES. 1 77

6CuCl, + yNaCISTS + 4H20 =

Cupric Sodium Water

choride sulphocyanide

6CuCNS + yKCl + 5HC1 + H2S04 + HCN

Cuprous Potassium Hydrochloric Sulphuric Hydrocyanic

sulphocyanide chloride acid acid acid.

If the sulphur compounds are not removed, volatile organic
sulphur compounds appear in the distilled glycerin, and
unfit the product for the uses of the dynamite manu-
facturer.*

III. Benno, Jappe", & Co.'s Method. — Instead of
using sodium chloride to separate soap in the pan, Benno,
Jappe, & Co. recommend the use of sodium sulphate. The
lyes are then neutralized by acid sodium sulphate, and the
salts removed by evaporation and filtration. The glycerin
is then purified by distillation.

IV. Clolus' Method. — First neutralize with hydro-
chloric acid; then remove sodium chloride by means of a
turbine, or by dialysis; evaporate to 32° B.; pass hot air to
render the glycerin anhydrous, in which the sodium chloride
is insoluble, or nearly so ; or obtain anhydrous glycerin by
evaporation in vacuo, and subsequent distillation.

V. Fleming's Method.! — FLEMING proposes to subject
the spent lyes to dialysis. He shows that the four soap-
works at Neuwied alone produce annually about 1500 tons
of waste liquors, containing about 75 tons of glycerin. The
percentage of glycerin in the lyes varies from 0.92 to 7.8.
The most effectual means for removing the salts contained
in the lyes previous to distillation is to subject them to
osmotic motion. The lyes are concentrated in suitable pans
by steam heat, and then neutralized by sulphuric acid. The
quantity of acid required depends upon the amount of

* ALLEN, " J. Soc. Chem. Ind." 1887, p. 88.

f "Dingl. Polyt. Journ." ccxliii. 330-333 ; " Year Book of Phar-
macy," 1882, p. 257.

178 SOAPS.

sodium carbonate present in the lyes. As, owing to the vio-
lent evolution of carbonic acid, it is difficult to obtain a
perfectly neutral solution, it is preferable to add a slight
excess of acid, which, after the precipitation and separation
of the sodium sulphate, is removed by lime. The liquor is
re-evaporated with steam, a further (small) quantity of
sodium sulphate and chloride crystallizing out on cooling.
It is now osmosed and concentrated, and, after this opera-
tion, is sufficiently free from mineral constituents to be dis-
tilled, either per se or in conjunction with crude glycerin
obtained in the manufacture of stearic acid. The loss of
glycerin by distillation is very small, and, as regards the
purity of the resulting product, it is shown that it fulfils
all the requirements necessary for the successful preparation
of dynamite. The great feature of the process is that,
unlike molasses, the liquor treated does not attack parch-
ment paper. A large quantity of glycerin remains in the
osmose water, and may be recovered by concentrating and
distilling the liquid.

FLEMING has also patented the use of a gutta-percha
membrane, which, he states, is traversed by salt, but is im-
permeable by glycerin.

VI. O'FarrelTs Method. — Evaporate and treat with
methylated spirit, which dissolves the glycerin, and then
distil. Or, the lye may be used again in the production of
soap till a maximum of glycerin is obtained in a minimum
of lye.

VII. Payne's Method. — Neutralize with hydrochloric,
sulphuric, or nitric acids. Separate gelatinous and albu-
minous matters by addition of tannin. Filter, concentrate,
and distil off the glycerin.

VIII. Reynolds' Method.* — The lye is first concen-

* Patent No. 1322, June 10, 1858.

GL YCERIN FROM SPENT L YES. 1 79

trated by evaporation, and the saline matter, which gradually
separates, is removed from time to time. When the fluid
is sufficiently concentrated (ascertained by the boiling point
having risen to 116° C.), it is transferred to a still, and the
.glycerin distilled off by means of superheated steam intro-
duced into the still. The distillate is next concentrated,
•and brought to the consistency of a syrup in a vacuum pan.
If greater purity is required, it may be obtained by repeat-
ing the process, and the little colour that remains may be
removed by animal charcoal.

IX. Thomas and Puller's Method. — Neutralize, eva-
porate and remove salts, and then add oleic, palmitic, or
stearic acid. The neutral glycerides so obtained, after being
washed, are treated, as in the candle industry, by the lime
saponification process, or by superheated steam.

X. Venables' Method. — The liquor from the soap,
-either before or after filtration, is neutralized by means of
aluminium sulphate, alum, or any soluble salt of aluminium,
or any substance containing soluble alumina. The sodium
hydrate and carbonate, combining with the acid, precipitate
the alumina, and the alumina, combining with some of the
organic matters and carrying off the rest, purifies the lyes.
Filter, and concentrate. Or, instead of only neutralizing,
the salt of aluminium may be added till the lye becomes
acid, and it may then be rendered alkaline by addition of
caustic lime or any other alkali which may be found con-
venient. The spent lyes may also be first partially neu-
tralized by the addition of a small quantity of hydrochloric
or sulphuric acid ; the remaining free sodium hydrate will
then be neutralized by the aluminium salt, which may be
added to exact neutrality or to excess ; in the latter case,
the liquid should be afterwards neutralized, or rendered
alkaline. Glycerin can then be obtained by distillation.

XI. Versmann's Method. — (i) The lyes are evaporated.

i So SOAPS.

until the liquor becomes so concentrated that the salts con-
tained therein begin to crystallize out.

(2) The liquor is then cooled, and filtered to get rid of
gelatin and albumen.

(3) Carbonic acid is then passed through the liquid*
Sodium bicarbonate is precipitated, and this is separated in
the usual way.

(4) After undergoing this treatment, the liquor is made-
to absorb gaseous hydrochloric acid until the remaining
sodium carbonate is converted into chloride, and further
until all, or almost all, the sodium chloride has been precipi-
tated.

(5) When the chloride has been separated, the liquor,,
containing water, glycerin, and hydrochloric acid, is evapo-
rated so as to get rid of the acid, which is absorbed in water
for using afresh.

(6) The dilute glycerin remaining can be purified by fil-
tering through animal charcoal, or by concentrating and
distilling.*

XII. Young's Method. — Evaporate the lyes by means.
of superheated steam. Neutralize by sulphuric acid, add cal-
cium carbonate, filter, and treat with a centrifugal machine
(such as is used to separate sugar from molasses). Evaporate
the separated crude glycerin, and distil.

* VEBSMANX, " Chem. News," June 24, 1881.

CHAPTER XIII.
TESTING SOAPS.

IT is impossible to know the real composition of a soap, and
consequently its value, except by analysis. For many pur-
poses it is sufficient to ascertain the proportion of water,
fatty acids, and alkali, while for others a full analysis is
-desirable.

Samples. — The sampling of soap for analysis requires
;great attention. The difficulties to be overcome are thus
exemplified by R. S. TATLOCK :* — A delivery of fifty boxes
of Italian olive-oil soap has to be sampled, the goods being
sold on the basis of 62 per cent, of fatty acids. The quality
of the total contents of each box may be different. The
proportion of valuable ingredients cannot be the same in
every bar of a given box, from the fact that some of the
bars have only their ends exposed to the outside, others
their ends and one side, a third series their ends and two
sides, while a fourth may be completely inside. Then,
&gain, the bars selected for analysis, for the same reasons,
are also in different conditions of dryness, and the sampling
by the analyst of each bar for his working sample becomes
•a matter for grave consideration. The problem is, What
..proportion of the fifty boxes are to be opened, from what
position in the box are the bars to be selected, and in what

* " Journ. Soc. Chem. Ind." 1884, p. 307.

1 82 SOAPS.

ways are the selected bars to be punched out so as to give
an accurate average for analysis 1 Each i per cent, of fatty
acids represents about £i I2S. 6d. on every ;£ioo value,
but probably any hard-and-fast method would be com-
pletely upset by the adoption of a different form or size of
box.

The following are some of the schemes that have been
proposed for conducting the analysis of soap in a systematic
manner : —

Dr. Leeds' Method.* — (i) Water. — Weigh out about 5
grams in very fine shavings on a dried, weighed, plaited
filter. Dry at 110° C. till weight is constant. The loss is
water.

(2) Uncombined Fat. — Transfer the filter containing the
dried soap to a funnel connected with the return cooler,
such as is used in the determination of the albuminoids in
milk, and connect with the funnel a small tared flask con-
taining 50 c.c. petroleum ether. Or, the filter may be
placed in the ordinary Soxhlet apparatus. After complete
extraction, distil off the ether, and the residue in the flask,,
dried at 110°, will be the uncombined fat.

(3) Free Alkali, (4) Combined Alkali, (5) Glycerin. —
Allowing the filter with the soap, now free from water and
uncombined fat, to remain in the apparatus, attach to it a
flask containing about 75 c.c. of 95 per cent, alcohol, and
extract.

To the alcoholic solution add a few drops of phenol-
phthalem ; if free alkali be present, neutralize with normal
sulphuric acid, and calculate the amount of uncombined
soda. (Free alkali, if present, may be detected qualita-
tively, by applying to a freshly cut surface of soap a drop

* "Chem. News," October 5, 1883, pp. 166-8; "3. Soc. Chem.
Ind." 1883, p. 479. A tabular arrangement of Dr. LEEDS' scheme is.
given on pp. 184, 185.

TESTING SOAPS. 183

of mercurous nitrate, which will give a greyish tint, or a
drop of phenol-phthalei'n, which will give a pink coloration.)
After neutralization, add a large excess of water and boil
off the alcohol. To the aqueous solution add a large excess
of normal sulphuric acid, noting the quantity added.
Boil, cool, and decant through a small filter ; wash with hot
water, and decant, after cooling, through the filter until
litmus-paper is no longer reddened by the washings. The
filtrate contains the combined soda and the glycerin; the
residue consists of the fatty acids and resin. Neutralize
the filtrate with normal soda solution, and calculate the
amount of combined soda as JSTa20. Evaporate to dryness,
and extract the glycerin with absolute alcohol. Transfer
the alcoholic solution to a tared flask, distil off the alcohol,
dry at 100° C., and weigh the residue as glycerin.

(6) Fatty Acids and Resin. — With a little petroleum
ether, dissolve the small amount of the fatty acids and resin
that may be on the filter through which the decantation
wras effected, add the solution to the larger bulk in the
beaker, evaporate off the ether, dry at 100°, and weigh the
combined fatty acids. Multiply this result, after deducting
the amount of resin, by 0.97; the product is the fatty
anhydrides.

(7) Resin. — The resin is separated according to the
method proposed by GLADDING.* About 0.5 gram of the
mixture of fatty acids and resin, are dissolved in 20 c.c. of
strong alcohol, and, with phenol-phthalem as an indicator,
soda is run in to slight super-saturation. The alcoholic
solution, after boiling for ten minutes to insure complete-
saponification, is mixed with ether in a graduated cylinder
till the volume is 100 c.c. To the alcoholic and ethereal
solution i gram of very finely powdered neutral silver

* " J. Soc. Chem. Ind." i. 205 ; " Chem. News," April 14, 1882.

1 84

SOAPS.

Dr. Leeds' Scheme

Weigh out 5 grams. Dry at

Treat witl

Residue is soap and minera

Extract is soap (fatty anhydrides, resin, and combined alkali), glycerin
and free alkali. Add 2 or 3 drops of phenol-pkthalei'n. If neces
sary, titrate with normal sulphuric acid.

Add a large excess of water, and boil off the alcohol. Decompose

with excess of normal H2S04. Note quantity added. Boil,

filter, and wash.

Filtrate. — Combined soda

Residue. — Fatty acids and resin. Dry

andglycerin. Titrate with

at 110° C., and weigh. Dissolve ail

normal soda solution.

aliquot part in 20 c.c. strong alcohol,

and, using phenol-phthalein as indi-

H2SO4, in
excess
of soda,
used cor-
responds

After titration
with soda,
evaporate to
dryness on the
water-bath.

cator, saponify with soda in slight
excess. Boil, cool, and add ether to
100 c.c. Decompose with AgNO3,
in fine powder, shake well for ten
minutes, and allow to settle.

to com-
bined soda

.Treat with abso-
lute alcohol.

Precipi-

Solution. — Ecsinate of sil-

in soap.

Evaporate the

tate is

ver. Filter 50 c.c. from

Calculate

alcoholic solu-

stearate,

the total 100 c.c. De-

as NazO.

tion to dryness
in a tared basin,

palmitate,
andoleate

compose with 20 C.C. HC1
(1:2). Allow the AgCl

and weigh as

of silver.

to settle, and evaporate

glycerin.

an aliquot part of the

ethereal solution in a

tared dish. Dry at 110°

C., and weigh.

After applying the correc-

tion for oleic acid, the

weight corresponds to

the resin. This weight,

subtracted from the com-

bined weight of fatty

acid and resin, gives the

fatty acids.

TESTING SOAPS.

185

'or Soap Analysis.

oo° C. Loss corresponds to water.

)etroleum ether.

constituents. Treat with alcohol.

1
Residue. — Na2COs, NaCl, Na2804, sodium silicate, starch, and in-

soluble residue. Wash with 60 c.c. water.

Filtrate.— Na2C03, NaCl, Na^SOv and
sodium silicate. Divide into four equal

Residue. — Starch and
other insoluble matter.

parts.

Dry the filter, and weigh.

Na2COs.

NaCl.

Na2SOt.

Sodium

Starch.. — Boil with dilute

Titrate
| with
1 normal
H2S04,
and
calculate
as
Na2C03.

Titrate
with
AgNOr
or weigh
as AgCl.
Calculate
as NaCl.

Weigh as
BaSO4.
Calculate
to

silicate.

Decompose
with HC1,
and deter-
mine soda
combined in
silicate and
silica.

acid to convert into
C6H1206, and titrate by
FEHLING'S solution. Sub-
tract the weight of starch
so found from the total
residue. The difference
is the insoluble mineral
constituents.

i .

1 86 SOAPS.

nitrate is added, and the contents of the cylinder are shaken
thoroughly for ten or fifteen minutes. After the precipitate
has settled, 50 c.c. are measured off, and, if necessary, filtered
into a second graduated cylinder. A little more silver
nitrate is added to see if the precipitation is complete, and
then 20 c.c. of dilute hydrochloric acid (i : 2) to decompose
the silver resin ate. An aliquot part of the ethereal solution
is evaporated in a tared dish and weighed as resin, deducting
a small correction* (0.00235 gram for 10 c.c.) for oleic acid.
The amount of resin subtracted from the combined weight
of fatty acids and resin, as found before, gives the fatty
acids.

(8) Sodium Carbonate; (9) Sodium Chloride; (10) Sodium
Sulphate; (n) Sodium Silicate.

(12) Insoluble Residue. — The filter in the funnel con-
nected with the return cooler, after treatment with alcohol,
contains the mineral constituents of the soap. The contents
of the filter are washed with cold water till the washings
amount to 60 c.c. The filter is then dried, and weighed.
The weight gives the insoluble residue and starch. The
starch is converted into glucose with dilute acid, and
titrated with FEHLING'S solution. The weight of starch so
found, subtracted from the total weight of insoluble residue
and starch, gives the insoluble mineral constituents. The
aqueous solution of 60 c.c. just mentioned is divided into
four equal parts, in one of which is determined the sodium
carbonate by titration, and, in the other parts, the chloride,

* Dr. C. E. A.WRIGHT and C. THOMPSON (" J. Chem. Soc." 1886, p.
175) consider GLADDING' s process more satisfactory than any other
for the estimation of resin, but they show that this correction-factor
is by no means universally applicable. With pure stearic or oleic
acid, it is much too large ; with acids from castor oil, far too small ;
but with mixtures such as are likely to occur in the manufacture
of soaps the results afforded appear to be not far from the truth.

TESTING SOAPS. 187

the sulphate, and the silicate, respectively, by any convenient
method.

Pilsinger's Scheme.* — (i) Water. — In the case of hard
soap, 5 grams, scraped from the sides and centre of a fresh
section, are first very gently warmed, to avoid direct melt-
ing, then over a water-bath, and finally in a drying box
at 1 00° C., until the weight remains constant.

For soft soap, 10 grams are taken, spread in a thin layer
over a large watch-glass, and treated in the same way.

(2) Vnsaponifiedt or Free, Fat. — The dry residue from
(i) is finely powdered, and washed on a filter three or
four times with lukewarm petroleum ether. The filtrates
are collected in a weighed beaker, evaporated, dried, and
weighed.

(3) Free Alkali. — The residue from (2) is digested for a
short time with alcohol (95 per cent.), slightly warmed,
filtered, the residue on the filter washed with warm alcohol,
and the filtrate, to which a few drops of a phenol-phthalei'n
solution are added, titrated with — - sulphuric acid.

(4) Foreign Bodies. — These are found, by the usual
methods, together with the chlorides, sulphates, and car-
bonates of the alkalies on the filter in (3).

(5) Fatty Acids. — The neutralized alcoholic solution from
(3) is mixed with water in a moderate-sized porcelain basin,
the fatty acids precipitated by sulphuric acid, and, after
melting and settling, 5 grams of dry wax are added. When
the whole is cool, the fat-acid wax is removed, washed with
water and alcohol, dried without melting, and cooled. The
weight — 5 grams = the quantity of fatty acids.

(6) Glycerin. — The liquid from the cake of fatty acids is
treated with a small excess of barium carbonate, heated,

* " Chemiker Zeitung," April 17, 1884 ; " Chemist and Druggist,'"
1884, p. 290.

1 88 SOAPS.

filtered, the filter washed with hot water, and the filtrate
evaporated to dryness. The residue is repeatedly washed
with alcoholic ether, the filtrate evaporated in a porcelain
dish, dried at a temperature of 70° C., and weighed.

(7) Total Alkali. — 10 grams of another portion of soap,
prepared as in (i), are dried in a platinum dish, and then
heated till all the fatty acids have been destroyed. The
porous carbonaceous residue is boiled with water, filtered
into a £-litre flask, and the filter washed with hot water
till the washings cease to give an alkaline reaction. The
bulk is then made up, the whole well mixed, and 25 c.c.
( = i gram soap) of the solution are titrated with sul-
phuric acid. The result represents the amount of total
alkali, and, after deducting the quantity of free alkali,
found by (3), the remainder is the proportion of alkali
combined with fatty acids, and existing as carbonate and
silicate.

(8) Chlorine. — The neutral titrated solution from (7)
may be used for the determination of chlorine by ~j silver
solution.

(9) Silicic Acid. — 75 c.c. of the solution from (7) are
treated with excess of hydrochloric acid, evaporated to dry-
ness, treated with water, filtered, and the residue ignited
and weighed as silica.

(10) Sulphuric Acid. — The filtrate from (9) is boiled,
and, while boiling, barium chloride is added, the precipitated
barium sulphate washed, dried, and weighed, and calculated
as sodium, or potassium, sulphate.

(n) Potash and Soda, if both are present, must be
determined in the usual way by platinum chloride.

In many methods of analysis met with in text-books,
directions are given to weigh out for each operation small
portions (i to 5 grams) of the sample. In a communica-
tion from the laboratory, Owens College, Manchester, the

TESTING SOAPS. 189

following objections are taken to this method :* — 1°. Soap
is extremely variable in composition, and considerable varia-
tions are possible in a single sample. 2°. It is continually
losing water by evaporation from its surface. As the soap
is usually weighed in the form of thin shavings, the
surface exposed is, in relation to the weight taken, very
considerable.

These two sources of inaccuracy may be obviated thus :
— A section is cut through the bar at right angles to its
length, weighing 60 to 80 grams. This is dissolved in dis-
tilled water by the aid of heat, and the bulk made up to
i litre (at 60° F.). 50 c.c. are taken out for each of the
following operations, immediately after well shaking the
liquid, as some of the alkaline salts of the fatty acids
separate out from the solution on cooling.

i°. Total Alkali. — 50 c.c. of the solution are diluted to
about 200 c.c., coloured faintly with eosine, and standard
acid run in, taking care to stir briskly with a glass rod.
The neutral point is extremely well marked by the decolor -
ization of the whole. The cause of the disappearance of the
colour is the union of the fatty acids with the eosine at the
moment of their complete separation.

2°. Unconibined Alkali. — 50 c.c. are added to 300 c.c.
of a saturated solution of common salt, which, of course,
must be neutral to test-paper, and the volume made up
to 400 c.c. The neutral alkaline salts of the fatty acids
(i.e., true soap) are precipitated. Any excess of alkali
present remains in solution, and is determined in an aliquot
part of the nitrate. The filter must not be moistened
previous to filtration. The total uncombined alkali is
calculated therefrom, and deducted from the total alkali

* " Chem. News," January 5, 1877; UKE'S "Dictionary," iv.
822.

190 SOAPS.

already found. Thus the combined and unconibined alkali
are determined. (This method is less reliable than the
alcoholic treatment, pp. 182 and 187.)

3. Fatty Acids. — 50 c.c. of the solution are introduced
into a stoppered separating funnel, decomposed with excess
of acid, and agitated with carbon disulphide until the
liberated fatty acids are dissolved. The disulphide solution
is then drawn off into a tared flask, and the aqueous solution
is washed once or twice with small portions of disulphide,
and the washings are added to the contents of the flask.
The disulphide is then distilled or evaporated off. The
fatty acids are purified from the last traces of carbon di-
sulphide by heating the flask for a short time at 100° C.
After cooling, the weight, less the tare of the flask, gives the
weight of the fatty acids.

Ether may be used instead of CS2, but there is this dis-
advantage, that in the separator it will form the upper layer,
whereas carbon disulphide forms the lower, and hence is
more readily manipulated.

4. Water. — The direct estimation is effected by evapora-
ting 50 c.c. of the solution to dryness on the water-bath,
-and finally in an air-bath at from 100° to 120° C. The
residue is anhydrous soap, and from its weight the per-
centage in the sample is calculated.

When thin shavings of soap are dried in the usual
manner, the author of the process considers that the last
portions of water, amounting to from i to 2 per cent., are
not driven off.

5. Mineral Impurities and Unsaponified Fat may be de-
tected by taking the dried soap from the preceding opera-
tion, dissolving in strong alcohol, and filtering through a
funnel surrounded by a hot- water jacket. The former
remain on the filter as an insoluble residue, the weight
of which may be readily ascertained.

TESTING SOAPS. 191

The alcoholic filtrate is evaporated with successive ad-
ditions of distilled water. Any unsaponified fat or resin is
thus separated from the soap, which remains in the aqueous
solution. This solution may be used for i, 2, or 3.

Estimation of Detergent Value of Soap.

The following volumetric method affords a rapid means
of comparing commercial soaps as to their respective deter-
gent powers.* A standard soap is first chosen, by means of
which the relative saponifying value of any other soap may
be ascertained. The most suitable standard is the mottled
Marseilles soap, generally known as Castile soap. The com-
position of this soap is, in round numbers : —

Soda 6

Fatty acids 64

Water 30

100

i gram of this soap will be exactly neutralized by 0.1074
gram pure calcic chloride, or 10 grains by 1.074 grain.
Therefore, a solution of 1.074 gram CaCl2 in a litre of
water, or 10.74 grains in 10,000 grains, will suffice to
neutralize respectively 10 grams or 100 grains of the
standard soap dissolved in the same volume.

PONS f applies the above process in the following way : —
1°. 10 c.c. of the standard calcic solution are placed in a
stoppered bottle — holding 70-100 c.c. — with about 20 c.c.
distilled water.

2°. 10 grams of the sample of soap are now treated with
100 c.c. alcohol (sp. gr. 0.825) by means of rubbing or
shaking with gentle heat ; the real soap dissolves, and leaves
all mineral or foreign matters, which may be filtered off,

* BUTTON, " Volumetric Analysis," p. 53.

f " Journ. de Pharm. et Chem." April 1865, p. 290.

192 SOAPS.

and afterwards, if necessary, examined. The filtrate is
diluted to i litre with distilled water.

3°. This solution is then cautiously run from a burette
into the 10 c.c. of lime solution, with frequent shaking,
until a lather is obtained.

4°. The 10 c.c. of lime solution divided by the number of
c.c. of soap solution required will show the richness of the
soap compared with the standard. Thus, if 10 c.c. only are
used, the soap under examination is of the same quality as
the standard; if 15 or 20 c.c. are required, the percentage
will be yf x 1 00 = 66 per cent., or -Jg- x 100 = 50 per cent.,
and so on.

A. H. ALLEN'S modification of this process is as follows : —
He ascertains what measure of a standard solution of the
sample must be added to 50 c.c. of a very dilute solution
of calcium chloride, or sulphate, solution, in order to obtain
a persistent lather on shaking. The soap solution is made
by dissolving 10 grams of the sample, as in the preceding
method, in proof spirit (sp. gr. .920), filtering, and diluting
the filtrate with proof spirit to i litre. The test is made
exactly as in determining the hardness of waters, the soap
solution being added to the standard hard water in small
quantities at a time till a lather is obtained, on shaking,,
which persists for at least five minutes when the bottle used
for the operation is placed on its side. The standard hard
water may be conveniently prepared by exactly neutralizing
40 c.c. of decinormal sulphuric or hydrochloric acid by
cautious addition of lime water, and diluting the solution
to i litre, when it will have a hardness of 14 degrees in.
CLARK'S scale.*

M. Cailletet's Method t of determining the Fatty

* "Commercial Organic Analysis," second edition, ii. 250.
f "Bulletin de la Societe industrielle de Mulhouse," No. 144,
tome xxix. p. 8.

TESTING SOAPS. 193

Acids. — A standard acid is prepared by diluting 189.84
grams of strong sulphuric acid to i litre at 15° C. Of this
acid 10 c.c. neutralize 1.2 gram of soda, and this quantity
is therefore sufficient to decompose 10 grams of soap, as the
amount of alkali present never exceeds 1 2 per cent.

Into a tube of 50 c.c. capacity, and divided into 100 equal
parts, are poured 10 c.c. of the standard acid and 20 c.c. of
turpentine ; 10 grams of the sample in thin shavings are
then added. The tube is then closed with the stopper, or
with a good cork, well shaken for a few minutes till the
soap is dissolved, and then left at rest for fifteen minutes,
or till the oily solution of the liberated fatty acids has com-
pletely separated from the watery liquid.

In reading off the volume of the turpentine solution after
the experiment, a deduction of half a division, or \ c.c., is
made, to allow for the diminution of the capacity of the
tube owing to the thin film of watery liquid which adheres
to the inner surface of the tube. If the oily stratum occu-
pies 53 divisions, or 26.5 c.c., then, deducting 20 c.c. for the
volume of turpentine employed, the remainder, 6.5 c.c. (or
65 per cent.), is the volume of fatty acids in the soap.*

Determination of Glycerin. — Many methods have
been proposed to effect this. The usual method is to dis-
solve a known weight of soap in water, acidulate with sul-
phuric acid, filter off the separated fatty acids, neutralize
with sodium carbonate, evaporate to dryness, and treat the
residue with strong alcohol, which dissolves glycerin, and
leaves behind sodium salts. Dr. WRIGHT j* points out that
this residue left on evaporation is rarely pure, most soaps
containing small quantities of substances derived from the
original fats and oils, which are soluble in the acidified

* This x by their sp. gr. = percentage by weight.
t Cantor Lectures on " Toilet Soaps," May 1885, p. 40.

194 SOAPS.

aqueous fluid, and thus become more or less dissolved out
by the alcohol, so that soaps containing no trace of glycerin
will still furnish small percentages of alcoholic extract when
thus treated. Sodium chloride, being slightly soluble in
ordinary alcohol, may also be contained in the extract.
By re-dissolving the dried extract in absolute alcohol, and
adding one and a half times its volume of ether, a certain
amount of substances other than glycerin is generally pre-
cipitated, but, in most cases, even this purification fails to
yield pure glycerin, especially in presence of sugar.

Dr. WEIGHT found the following method gave fairly
accurate results : — The aqueous acid solution obtained after
separating the fatty acids as above described is rendered
strongly alkaline with aqueous caustic soda, and then dilute
.copper sulphate solution is dropped in with agitation, until
the copper hydroxide thus formed begins to fail to dissolve.
The filtered blue solution is compared calorimetrically with
a known quantity of a standard solution of glycerin treated
side by side in the same way. When sugar is present, the
alcoholic extract, obtained as above, must be heated with
dilute sulphuric or other acid, for some time, so as to invert
the sugar. The fluid is then rendered alkaline, and copper
sulphate dropped into the boiling liquid as long as suboxide
of copper is reduced, after which the calorimetric estimation
of the glycerin is proceeded with as before, the comparison
being preferably made with a known solution of glycerin and
cane sugar treated simultaneously with the sample under
examination.

With care and practice, fairly good results can be thus
obtained, more especially when sugar is absent. The follow-
ing figures illustrate the numbers which WRIGHT obtained
jn analyses for glycerin, the values being percentages : —

TESTING SOAPS.

195

Nature of Soap.

Crude
Alcoholic
Extract.

Extract
purified by
Ether.

Glycerin
indicated by
Copper Test.

Opaque untinted soap, mo-

derate quality .

7.0

6.1

6.OO

High-class Parisian glycerin [

soap, not transparent

8.1

7-9

S.oo

Cold process soap .+ much

unsaponified fat

6.6

4-9

4-75

British so-called glycerin

soap, opaque

7-9

0.60

British transparent soap,

without sugar .

19.0 17.6

15.00

Ditto + 10 per cent, of sugar

6.1 4.0

o.oo

Dr. WRIGHT states that the entire absence of glycerin,
from a toilet soap necessarily, proves that the whole mass
has been prepared either by a boiling process, or by satu-
rating a free fatty acid, as oleic acid, with alkali, or by both
processes combined. On the other hand, the presence of a*
quantity not far removed from the percentage of combined
alkali, expressed as Na20, suggests that the whole has been
probably prepared by the cold process, for, as ordinary oils
•and fats are substantially tri-glycerides, i equivalent of
fatty matter will yield 92 parts of glycerin, and fatty acids
equivalent to 93 of ISTa20. When larger quantities of
.glycerin are present, extra glycerin must have been added to
the materials during the manufacture of the soap. When
small quantities only are present, constituting only a fraction
•of the percentage of combined alkali, expressed as Na20, the
soap is probably a blended mass, consisting partly of boiled
#,nd partly of cold-process soaps.

MUTER'S METHOD.* — This may be used for the determina-
tion of glycerin in soap and soap-lyes. The process is based

* "Analyst," 1881, p. 41; "Year Book of Pharmacy," 1881, p,

121.

O 2

196 SOAPS.

on the power of glycerin to arrest the precipitation of
cupric hydrate by alkalies. The modus operandi is as fol-
lows : —

1 i ) Take i gram of absolute glycerin and wash it into a
long, stoppered, graduated tube, having a stop-cock at 50 c.c.
from the bottom.

(2) Add 50 c.c. of a strong solution of potassium hydrate
(i in 2) and then a weak solution of cupric sulphate very
gradually, and with constant shaking, until a fair amount
of cupric hydrate is produced which remains undissolved ;
make the whole up to a given bulk, close the tube, and set
it aside to settle.

(3) When perfectly clear, run off from the tap into a
beaker a given volume of the deep-blue liquid, and add to
it the slightest possible excess of nitric acid.

(4) Pour in a definite excess of ammonium hydrate,
bring the beaker under the burette charged with volu-
metric solution of potassium cyanide, and run in till de-
colorized.

The number of c.c. of the cyanide used, after calcula-
ting to the whole bulk originally in the tube, represents
i gram of glycerin. The result has, however, to be corrected
by going through a blank experiment, with the same
amounts of everything, but without glycerin, and deducting
the c.c. of cyanide taken from that previously found. This
precaution is necessary because copper hydrate is not quite
insoluble in the strong alkali, but, once made and deducted,
"the difference gives the true value in glycerin of the cyanide
solution, and, when that has been thus standardized, any
number of estimations can be quickly made.

The glycerin to be determined must first be isolated,
as free from intermixture as possible, as previously de-
scribed.

TESTING SOAPS. 197

Determination of Carbolic Acid in Soap.*— (i) 5
.grams of the soap are dissolved in warm water, with addition
of from 20 to 30 c.c. of a 10 per cent, solution of caustic
soda, according to the proportion of phenols believed to be
present.

(2) The cooled solution is then agitated with ether, and
the ethereal layer separated and evaporated at a low tem-
perature. The weight of the residue gives the amount of
hydrocarbons, <fcc., in the quantity of the sample taken.
The odour towards the end of the evaporation and that
observed on heating the residue will give considerable in-
formation as to the nature of the admixture. Odours
suggesting gas-tar and burning gutta-percha are very
•common.

(3) The alkaline liquid separated from the ether is then
treated in a capacious separator with an excess of strong
brine, which completely precipitates the fatty acids as
sodium salts. The liquid is well agitated to cause the soap
to filter, and is then passed through a filter. In cases where
the soap does not readily coagulate, an addition of a small
quantity of tallow or palm-oil soap, previously dissolved in
water, will usually overcome the difficulty. The precipitated
soap is washed twice by agitating it with strong lime, the
washings being filtered and added to the main solution,
which is then diluted to i litre.

(4) 100 c.c. of this solution ( = 0.5 gram of the sample
of soap) are then placed in a globular separator, and acidu-
lated with dilute sulphuric acid, when it should remain
perfectly clear. Standard bromine water is then added
from a burette, the stopper of the separator inserted, and

* A. H. ALLEX, "Analyst," 1886, p. 103; "Year Book of Phar.
inacy/' 1886, p. 138.

198 SOAPS.

the contents shaken vigorously. More bromine water is
then added, and the agitation and addition of bromine solu-
tion repeated alternately until the liquid acquires a faint,,
but permanent, yellow tint, showing that a slight excess of
bromine has been used.

If crystallized carbolic acid has been emploj'ed for making
the soap, the bromo-derivative is precipitated in snow-whiter
crystalline flocks, which allow the faintest yellow tint, due
to excess of bromine, to be observed with great facility. If
cresylic acid be the chief phenol present, as in the case of
soaps made with an article of a quality similar to CALVERT'S.
No. 5 carbolic acid, the precipitate is milky, and does not
separate well from the liquid, but the end of the reaction
can still be observed. The addition of a solution containing
a known amount of crystallized phenol is a useful device in
many cases, as the precipitate then curdles readily, and the
yellow coloration can be easily seen.

The bromine solution is made by mixing in a separator
i measure of saturated bromine water with 2 measures
of water. This solution contains approximately i per cent.,
and should be run out from the tap of the separator into
the MOHR'S burette used for the titration. The burette
should be closely covered, and the last few c.c. of the solu-
tion contained in it should never be employed for the titra-
tion, as it is apt to lose strength. The bromine water must
be standardized, immediately before or after use, by a solu-
tion of CALVERT'S No. 2 or No. 5 carbolic acid, according to
the kind of acid the titration has indicated to be present in
the soap. This solution is made by dissolving 0.5 gram of
the coal-tar acid in 20 c.c. of a 10 percent, solution of caustic
soda, together with 5 grams of a non-carbolic soap. The
solution is then precipitated with brine in the same manner
as the sample, the nitrate diluted to i litre, and 100 c.c_
acidulated and titrated with the bromine solution used for

TESTING SOAPS. 199

the sample. The volume of bromine solution used is that
required by 0.05 gram of coal-tar acid of approximately the
same quality as that contained in the soap.

The mode of preparing the bromine solution, and the
mode of conducting the titration may be modified in any of
the various manners proposed by different chemists, but the
method of operating just described is quite accurate enough
for the purpose in view, and has several practical advantages.
In any case the bromine solution should be standardized by
carbolic acid in the manner recommended, and its power of
brominating calculated.

(5 The remaining portion of the liquid filtered from the
precipitate of soap may be evaporated to a small bulk, acidu-
lated with dilute sulphuric acid, and the separated phenols
measured, but the quantity is not sufficient to make the
method satisfactory. It is generally better to employ the
solution for the isolation of the bromo-derivatives. For this
purpose it is acidulated with sulphuric acid, without previous
concentration, and bromine water added in slight excess.
From 5 to 10 c.c. of carbon disulphide are then added, the
liquid is well agitated, and the carbon disulphide tapped off
into a small beaker. The aqueous liquor is agitated with
fresh quantities of carbon disulphide (of 5 c.c. each) till it
no longer acquires a red or yellow colour. The disulphide
is then allowed to evaporate- spontaneously, when a residue
is obtained consisting of the brominated derivatives of the
phenols present in the soap. If crystallized carbolic acid of
fairly good quality was introduced into the soap, the bromo-
derivative is obtained in fine long needles having very little
colour j and if all heating was avoided during the evapo-
ration of the carbon disulphide, the weight of the residue
multiplied by 0.281 gives a fair approximation to the
amount of carbolic acid ; but if a crude liquid article, con-
sisting mainly of cresylic acid (e.g., CALVERT'S No. 5 car-

i 2OO

SOAPS.

bolic acid) has been employed, the bromo-derivative will be
deep yellow, orange, or red, with little or no tendency to
crystallize, and the weight will not afford even a rough in-
dication of the amount of coal-tar acid present.

It must be borne in mind that in this process a loss of
2 or even 3 per cent, of carbolic acid is liable to occur
through evaporation.

The following table shows some of the results which Mr-
ALLEN obtained by the analysis of representative samples of
commercial carbolic soap : —

Phenols.

Percentage.

Nature.

Medical carbolic, 20 % pure .

20% „ .

Carbolic toilet, 10 °/ .
10 % . .
Domestic carbolic .

5> J» • • •

Carbolic soft, 10 %

M 10%

30.50
17.00
3-60
3-40
4.80
6.40
9.90
8.20

o. 16

Pure phenol

5) 5>

Common carbolic

10
II
12
13

14
IS

16
17

Transparent carbolic
,, coal-tar
No. i carbolic

5» »> • . .

No. 2 „ ,

1> » ...

Carbolic

3.20
1.50

2.50
5-40
4.40
3-50
2.60

I.IO

Pure phenol
Common carbolic

Impure phenol
Common carbolic

0.50

Impure

Disinfecting ....
Sanitary ....

none
0-75

Impure phenol

Free Alkali in Toilet Soaps. — In view of the objection-
able effects produced by excess of alkalinity in toilet soap,
and of the circumstance that the best British and foreign
makes are found by analysis to contain only very small
quantities of free alkali, expressed as anhydrous soda, Na,O,
not exceeding 0.20 to 0.25 per cent, by weight (the com-

TESTING SOAPS.

201

t>inecl alkali being usually 7 to 9 per cent., or some forty
times as much), WRIGHT* classifies toilet soaps in three
grades, from the point of view of the amount of free alkali
present — viz. :

First Grade. — Soaps which are, if not neutral, at any rate
so devoid of free alkali that the amount of total alkaline
matter present, in forms other than actual soap, does not
exceed J^th part (2.5 per 100) of the alkali combined as
soap.

Second Grade. — Soaps in which the free alkali, although
exceeding the above limit, does not exceed -j3<yths of the
combined alkali (7.5 per 100).

Third Grade. — Soaps in which the free alkali exceeds the
second limit.

Comparison of Soaps.t — GASSLER has compared two
German resinous soaps with an English cold-water soap,
and considers that the former are superior to the latter.

German Soaps.

English Cold-
water Soap.

Fatty acids
Resin .
Soda .
Talc .
Water .

56.25
14-75
12-75

16.25

n.
53-65
17-35
12-55

16.45

46.87

23-!3
12.00
I.OO

18.00

The tables of analyses on p. 202 are of .interest, as
giving the comparative compositions of some colonial and
English soaps. £

Cost of Soap. — The question is sometimes asked, " Can
the first cost of a soap be deduced from the figures obtained

* Cantor Lectures on " Toilet Soaps," May 1885.
f " J. Soc. Chem. Ind." 1882, p. 371.

j " Colonial and Indian Exhibition Reports : Oils and Fats," by
LEOPOLD FIELD, p. 278.

202

SOAPS.

•0 S3 .

invo co H

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cooo t^ O

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^ co ci vo'

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TESTING SOAPS. 203.

on analysis ? " It is difficult always to do this with perfect
accuracy. If, however, the percentages so obtained b&
divided by 5, the quotient will be in cicts. per ton, and a
calculation as to cost may then be made at the current
prices of materials, as in the example given on p. 106. It
is necessary, however, that judgment be exercised in form-
ing conclusions from the results of such a calculation.

PART II.— CANDLES.

CHAPTER I.
DEFINITION AND HISTORY.

Definition. — A candle may be defined as a cylinder of fat
surrounding a fibrous thread, or wick; "a contrivance in
which, for the purposes of illumination, a wick of fibrous
material is employed to effect the combustion of fatty
bodies;"* "a wick surrounded by a coating of wax or
tallow ;"f " a cylindrical or slightly conical rod, formed of
solid fat, enclosing a bundle of parallel or twisted fibres of
cotton, called the wick, through which the melted fat is
drawn up to the region of combustion. "J

The chief point of difference between a candle and a lamp
is that in the former the fuel is a solid, which is gradually
liquefied in the required quantity by the heat of the flame,
whilst in the latter the fuel is, at common temperatures, a
fluid.

History. — The early history of candles is involved in

* "Jury Reports, Exhibition 1851," p. 615.

f L. FIELD, Cantor Lectures, " Solid and Liquid Illuminating
Agents," 1883, p. 7.
J RICHARDSON and RONALD'S " Technology," vol. i. pt. ii. p. 425.

206 CANDLES.

some obscurity. The Hebrew word translated candle in the
Old Testament probably means lamp. Possibly the torch
(Lat. tortium, a twisted thing) may have been the earliest
form of the candle. PLINY * mentions that the books found
in the grave of NUMA were in a box bound round with
candles. These candles were, it is thought, pitched rope.
PLINY also states f that the pith of " brittle rushes," which
grow in marshy districts, separated from the rind, was used
for making tuatc/i-candles and funeral lights to burn by dead
bodies whilst lying above ground. He does not, however,
say anything as to the nature of the fat employed, so that
it cannot be certainly inferred whether the reference is to
candles or to a kind of lamp.

BECKMANNJ has recorded that the Emperor Constantine,
about the beginning of the fourth century, caused the city
of Constantinople to be illuminated with lamps and ivax
candles on Christmas Eve.

APULEIUS distinguishes wax and tallow candles by the
terms cerei and sebacei.

In the Saxon period we find that wax candles were not,
as a rule, made by professional chandlers, because the well-
known candles of King Alfred were manufactured by his
chaplains, whom he commanded to supply wax in sufficient
quantity, and to weigh it in such a manner, that, when there
was so much of it in the scales as would equal the weight
of seventy-two pence, six candles were to be made thereof,
each of equal length «^ that each candle might have twelve
divisions marked across it. Six of these candles, lighted in
succession, burned exactly twenty-four hours. §

* " Natural History," xiii. 13. f Hid. xvi. 37.

J " Hist, of Inven." BOHN'S ed., ii. 174.

§ ASSER'S "Annals," translated for BOHN'S "Six Old English
Chronicles," p. 84.

.HISTORY. 207

FOSBROOKE* states that in the Middle Ages wax candles
were made of various sizes, some exceedingly small, and
others weighing as much as 50 lb. He also states that they
were made in moulds, and that the wicks were formed of
twisted tow.

According to DUCANGE, persons who made and sold candles,
or candelarii, were known in the middle of the thirteenth
century.

In the fifteenth century " mould " candles were intro-
duced by the Sieur DE BREZ.

GILBERT WHITE, writing in 1789, thus describes the
method of making rush candles practised in Hampshire : —
The proper species of rush for this purpose seems to be the
Juncus conglomeratus, or common soft rush, which is to be
found in most moist pastures, by the sides of streams, and
under hedges. These rushes are in best condition in the
height of summer ; but may be gathered, so as to serve the
purpose well, quite on to autumn. As soon as they are
cut, they must be flung into water and kept there, for
otherwise they will dry and shrink, and the peel will not
run. At first a person would find it no easy matter to
divest a rush of its peel or rind so as to leave one regular,
narrow, even rib, from top to bottom, that may support the
pith ; but this, like other feats, soon becomes familiar, even
to children. When the rushes are thus far prepared, they
must lie out on the grass to be bleached and take the dew
for some nights, and afterwards be dried in the sun. Some
address is required in dipping them in the scalding fat, or
grease, but this knack also is to be attained by practice.
1600 rushes, weighing i lb., are coated with 6 lb. of
tallow, so that 228 lights weigh i lb. and cost a little
over 5^.t

* " Encyclop. Antiq." p. 472.

f "Natural History of Selborne,'7 p. 220.

208 CANDLES,

In the year 1799 WILLIAM BOLTS took out a patent in
England for improving the form, quality, and use of the
candle, the specification of which probably contains the
first account of an attempt to improve the quality of candles
made from tallow and other animal fats, by subjecting the
material to a considerable pressure during the act of cool-
ing, and which is, in effect, the preparation of the so-called
stearin from fats. He likewise describes a solid candle with
a short wick, which is placed in a holder, and kept pressed
on the end of the candle by a spring, or else the candle is
placed in a tube and pressed against the wick by a spiral
spring ; as well as other contrivances, some of which have
been revived and successfully carried out in our own
days.*

In 1830 the number of candle-makers in Great Britain
was 2695, who paid ^500,048 145. id. duty; since the
repeal of the duty in that year no record has been kept of
their number.

Yery little improvement took place in the manufacture
of candles till after the discovery by CHEVREUL of the true
nature of fats (see p. 51). In 1825 GAY-LUSSAC and
CHEVREUL took out a patent for making stearic acid candles
— the badly combustible glycerin being removed, and the
oleic acid being separated to be used in soap-making. But
it was not till 1834 that they maybe said to have succeeded
in making their candles perfect.

The kernels of the candle-nut tree (Aleurites moh(.ccanar
Willd.), a native of the islands of the Pacific, are used in
Fiji, the Hawaiian Islands, and Tahiti, when threaded on
the mid-rib of a palm leaf, reed, or stick of wood, as a sub-
stitute for candles. In Tahiti and Fiji the tree is called
Futui, and Doodoe is its title in Pitcairn's Island. In the

* "Jury Reports, Exhibition 1851," p. 617.

HISTORY. 209

history of the " Mutiny of the Bounty " it is stated that the
rooms in Pitcairn's Island were lighted up with torches made
of doodoe nuts strung upon the fibres of the palm leaf. The
nuts are also so strung and used by the Sans Bias Indians
in Central America, and a child is in attendance to knock
off each nut as it burns out. Each nut burns about ten
minutes.* They yield a light which was considered good
a century ago, but is now thought dull, smoky, and ill-
smelling.

In Java the kernels are cleaned, crushed, and mixed with
sufficient cotton or cocoa-nut fibre to give them the con-
sistence of stiff suet. This paste is then rolled round a
split reed or bamboo to form a kind of candle or torch.
These burn more regularly than the contrivance just men-
tioned, but they consume more rapidly than tallow candles,
and give out an unpleasant odour, so that they are used
only by the poorer classes. This tree must not be con-
founded with the candle tree (Parmentiera cerifera) nor
with the candle-berry tree (Myrica cerifera).^

* M. C. COOKE, " London Medical Kecord," 1860.
f " Chemist and Druggist," 1879, p. 149.

CHAPTER II.
MATERIALS AND THEIR PREPARATION.

Materials.

THE materials chiefly used in the manufacture of candles
are the following : —

1. Animal Fats. — Tallow; lard; stearin.

2. Vegetable Oils. — Cocoa-nut oil ; palm-oil and palm-

kernel oil ; piney oil, or tallow.

3. Waxes.

(a) Animal. — Bees'-wax; Pela, or Chinese wax;

spermaceti.

(b) Vegetable. — Carnauba; Chinese vegetable tallow ;

Japan ; myrtle ; palm.

4. Patty Acids. — Coco-stearic acid ; palmitic acid ;

stearic acid.

i. Animal Pats. — TALLOW. — This has already been
spoken of in treating of soap (p. 18), and various processes
for its purification have been described (pp. 32, 39-43).
Tallow consists chiefly of —
Stearin — stearic glyceride, C3H5(C18H3502)3 ;
Palmitin — palmitic glyceride, C3H5(C16H3102)3 ; and
Olein— oleic glyceride, C3H5(C18H3302)3

— the first predominating, but varying in proportion accord-
ing to the species, age, food, &c., of the animal from which
it is obtained. The greater the proportion of stearin, the
harder will be the fat and the higher its melting point.

MATERIALS. 21 r

The two great and inherent disadvantages of tallow as a
candle material are due to the presence in it of fluid olein,
and to the glycerin in combination with stearic anhydride
in the stearin. The former lowers the melting point of the
fat, and produces a great tendency in the candle to gutter,
while the glycerin, both of the olein and of the stearin, being
with difficulty consumed, diminishes the intensity of the
light, and at the same time causes an unpleasant odour, by
giving off, as a product of combustion, the highly pungent
acrolein (C2H3.COH), which is very perceptible when a
tallow candle is blown out.

The setting point of tallow is found for technical purposes
as for paraffin (English method), p. 229.

LARD. — Seep. 18. STEARIN. — Seep. 231.

2. Vegetable Oils or Pats. — COCOA-NUT OIL (see p. 21).
— This oil or fat is now more utilized for night-lights than
for the manufacture of candles. Candles have been made
from it, but not satisfactorily ; the untreated fat has too
low a melting point, and the presence of glycerin makes it
as objectionable as tallow. The caproic and caprylic acids
also give rise to unpleasant odours. The chief brands are
Cochin and Ceylon, of which the former is the whiter and
.sweeter, and is therefore more suitable than the latfcer for
night-lights.

PALM OIL (see p. 22). — Lagos oil is the brand command-
ing the highest price. Other brands are Brass, Bonny, Old
and New Calabar, Whydah, Accra, &c.

PALM-KERNEL OIL (see p. 22).

PINEY OIL, OR TALLOW. — This is obtained by roasting,
grinding, and boiling with water the seeds of Vateria,
indica, or piney tree. The oil rises to the surface and is
skimmed off. When cold it is a solid fat, melting at about
95° to 97° F. (35-36° C.), sp. gr. 0.926. Colour, white or
pale yellow, and odour somewhat fragrant.

P 2

212 CANDLES.

4. Waxes. — The substances known as waxes are ob-
tained partly from animal and partly from vegetable sources..
The term wax was formerly confined to bees'-wax, but candles.
are now frequently called wax candles, though made from
solid paraffin, or paraffin ivax.

Waxes proper chiefly consist of members highest in the
series of fatty acids, CnH2n02, partly free and partly in
combination with alcohol radicals. They differ from fats.
in being less readily saponified, and in yielding no glycerin
when so treated. The soap formed is also very sparingly-
soluble in water.

The waxes are solid at common temperatures — melt below
the temperature of boiling water — are sparingly soluble or
insoluble in water — soluble in ether, chloroform, carbon di-
sulphide, and in the volatile and fixed oils.

Animal Waxes. — BEES'-WAX. — This is obtained by
melting the honeycomb in water after the honey has been
removed, straining the liquid mass, re-melting the defe-
cated portion, and then casting into cakes, or discs.

Pure bees'-wax has a pleasant odour, a pale yellowish-
brown colour, and a specific gravity of 0.960 to 0.969. It
is brittle at 32° F. (o° C.), softens and becomes plastic at
88° to 90° F. (31.1-32.2° C.), and melts at 145° to 155° F.
(62.77-68.3° C.).

As met with in commerce, the wax varies in colour from
very pale yellow, or almost white, to a dark mahogany
shade. But, however different in colour, and from what-
ever country obtained, the chemical composition, according
to HEHNER, who has very thoroughly investigated it,* does
not vary to any great extent. The following are HEHNER'S
results from the analyses of eighteen samples of English
wax : —

* "Analyst," 1883, p. 16.

MATERIALS. 213

Average.
Free add, calculatedas : cerorig j from I3 to lfi 0/o = ^

fiqponifidble matter, calculated }

as myricin, [ „ 86 to 89.6 % = §8.09

C16H31(C30H61)CX J

Myricyl palmitate Total 102.49

In all cases the sum of the cerotic acid plus myricin is
higher than 100, the average being as given above. The
tendency of these figures is to show that English bees'-wax
-consists almost completely of cerotic acid and myricin, but
that it also contains a small quantity of a substance of a
lower molecular weight, probably the cerolein of LEWY.

In the case of seventeen foreign samples the fluctuation,
of composition was found to be more considerable than the
above, but this HEHNER considers to be due to a greater
degree of sophistication.

Before wax is employed for the manufacture of candles
it is necessary to bleach it. All waxes do not bleach with
«qual facility. According to BARCLAY, English, Hamburgh,
Odessa, Portuguese, Mogadore, Zanzibar, East and West
Indian, and North American waxes bleach readily, while
those from Cuba, Dantzig, Konigsberg, Gambia, and Gaboon
are only bleached with difficulty, and seldom acquire a good
colour.

There are two methods of bleaching wax — (a) Atmospheric;
{b) Chemical.

(a) Atmospheric Bleaching. — 1°. The wax is cut up into
.small pieces and placed in a vat, into which steam is ad-
mitted through a perforated coil. A small quantity of very
dilute sulphuric acid (in the proportion of i pint of strong
acid for each ton of wax) is added, and the whole boiled
and well agitated for some time. The impurities separate
and subside. This operation is called " clearing down."

2°. The melted, bright wax is next caused to pass into
•a tank, the bottom of which is perforated with holes about

214 CANDLES.

the size of an ordinary quill. Through these holes it trickles
in thin streams on to a revolving cylinder, or drum, half of
which is immersed in a cistern of cold water. The motion
of the cylinder carries up a layer of water, on which the
wax falls, and becomes divided into exceedingly thin ribbons.
These ribbons, by the revolution of the cylinder, are carried
under the water, and are removed by a rake as they rise to
the surface.

3°. The ribbons are then spread evenly and thinly on long
canvas sheets, and placed in the open air, so as to be ex-
posed to the influence of the sun and air, for a period vary-
ing from about four to ten weeks, according to the weather.
Frequent turning is required so as to expose every portion
to the sunlight, and frequent sprinkling with water is also
necessary. Once, or perhaps twice, during the period men-
tioned, the wax is re-melted, separated into threads again,
and spread out as at first.

It has been observed that in rainy weather the wax gets
a greyish tinge, which cannot afterwards be removed.

A wax that yields to the atmospheric process is termed
kind, while one that is not so readily bleached is called
stubborn.

(b) Chemical Bleaching. — Wax may be bleached by
chlorine, or by bleaching powder, or by WATTS' chrome pro-
cess. When chlorine is used, substitution products are formed ;
and when the wax is subsequently burnt, hydrochloric acid
is given off. The greenish colour which remains after the
chrome process may be removed by boiling the wax several
times with solution of oxalic acid. When treated by these
methods, wax becomes highly crystalline, and is unsuitable
for candle-making. Hence these methods need not be here
described.*

* For WATTS' chrome process, and other methods, see " Oils and
Yarnishes," pp. 192-200.

MATERIALS. 215

PE-LA, PIH-LA, OR CHINESE WAX. — This is produced upon
the young branches of Fraxinus chinensis, or wax tree, by an
insect (Coccus pe-lci). On being scraped from the trees, the
crude material is freed from impurities by spreading it on a
strainer, covering a cylindrical vessel which is placed in a
caldron of boiling water. The wax is received into the
former vessel, and, on congealing, is ready for the market.
It is perfectly white, translucent, and shining. It has a
marked crystalline structure, and melts at about 82-83° G.
(180° F.). It is much harder than spermaceti, and not
unctuous to the touch. Its sp. gr. is 0.809—0.811. It is
tasteless and inodorous, and crumbles into a dry inadhesive
powder between the teeth. It is soluble in essential oils and
naphtha, insoluble in water, and scarcely affected by boiling
alcohol, acids, or alkalies. Chemically it is cerylic cerotate
(C27H55.C2?H53OJ. The quantity which finds its way to this
country is now very small.

In China, candles are made of the substance itself, but it
is more commonly mixed with softer fats, and used for coat-
ing more easily fusible material, thus preventing guttering.
It is often coloured red with alkanet root, and sometimes
green with verdigris.*

SPERMACETI. — This is the solid fat which is dissolved in
sperm oil in the head-cavity of the sperm whale, or cachalot
(Physeter macroceplialus}, and which, after death, separates
as a solid. The name appears to have been given under the
erroneous belief that the substance was the spaivn of the
whale tribe (sperma ceti). The head-matter, as it is called,
is not the only source of spermaceti, as the blubber or body-
fat, after melting and cooling, also yields a deposit of it.
The following is an outline of the method of separating the
crystals of spermaceti from the oil : t —

* RONALDS and RICHARDSON, " Technology," vol. i. pt. ii. p. 464.
f "Jury Reports, Exhibition 1851," p. 626.

216 CANDLES.

1. Bagging. — The oil is filtered through long cylinders
of bagging, lined with linen, tied, at one end, to the nozzle
of a feed-pipe communicating with a tank elevated about
6 feet, and, at the other end, tied up with string. The oil,
pressed upon by the weight of its own column, readily
passes through, while the bags retain the solid portion.
The spermaceti, at this stage, is of a dingy-brownish colour,
and is called bagged sperm.

2. first, Pressing. — The bagged sperm is next placed in
hempen sacks, and subjected to a pressure of about 80 tons
in a hydraulic press, by which the greater portion of the
adhering oil is removed.

3. Second Pressing. — The pressed sperm is now melted
and crystallized by slow cooling, and, after being ground to
powder, is folded up in square pieces of bagging and then
subjected to the action of a much larger hydraulic press,
capable of exerting a force of 600 tons. The oil which runs
from this press contains a small quantity of spermaceti, and
is therefore returned to the bags to be filtered.

4. first Refining. — The spermaceti is next melted in a
large iron vessel, and boiled for some time with a solution
of caustic soda or potash, which readily saponifies the sperm
oil still adhering to the spermaceti, whilst it has scarcely
any action on the spermaceti itself. By this means the
sperm oil is removed in the form of soap.

5. Hot-pressing. — The purified spermaceti is next removed
from the boiler, and run into flat tin-moulds to crystallize.
It is then again ground to powder, placed in linen bags,
interleaved with horse-hair mats and previously heated iron
plates, and pressed in a horizontal hydraulic press, heated
by steam.

6. Second Refining. — The hot-pressed spermaceti is now
removed and boiled with a strong alkaline lye, the tempera-
ture reaching 235° F. (113° C.). By this final operation it

MATERIALS. 217

Incomes as colourless as water, and has only to be cast into
blocks for the convenience of storing.

Spermaceti, thus purified, consists mainly of cetylic palmi-
tate (C16H33.C16H31O2). It is white, scaly, brittle, neutral,
inodorous, and nearly tasteless. Its sp. gr. is 0.943 at
15° C., and it melts at about 110° to 120° F. (43.3—
48.8° C.).

Vegetable "Waxes. — CARNAUBA, OR STONE-WAX. — This
occurs as a thin film on the leaves, stalks, and berries of
the Carnauba palm (Copernicia cerifera), a native of Brazil.
The leaves, &c., are collected and dried, and the wax can
then be peeled or boiled off, melted in earthen pots, and
turned out when cold. It is of a yellowish colour, and very
hard and brittle. "When bleached, it is quite white. Its
sp. gr. is about 0.995-1.000 and its melting point 182—
185° F. (83.3-84.9° C.). ^

Its chemical composition is uncertain. STURCKE* found
it to contain myricyl alcohol (C30H620), free and in com-
bination as myricyl cerotate, to the extent of about 45 per
cent.

It is used sometimes to harden candles, but only in very
small quantity, as 2 per cent, of the wax would cause the
candle to crack. Heel-balls, for rubbing on the heels of
boots, &c., contain 50 to 60 per cent, of this wax mixed
with a little blacking, rosin, and soft wax.

CHINESE VEGETABLE TALLOW. — This is found enveloping
the kernels in the nuts of Stillingia sebifera (Exccecaria,
sebifera, Mull.). According to Dr. PORTER SMITH, the fat is
obtained in China from the seeds in the following manner : —
(i) The ripe nuts are bruised and the pericarp separated by
sifting. (2) They are then steamed in wooden cylinders, with

* LIEBIG'S "Annalen," ccxxiii. 283-314; "Year Book of Phar-
macy," 1885, p. 204.

21 8 CANDLES.

numerous holes at the bottom, which fit upon kettles or
boilers. The tallow is softened by this operation. (3) The
mass is then gently beaten with stone mallets, to separate
the tallow from the albumen of the seeds, and afterwards
sifted through hot sieves. (4) To remove the still remaining
brown testa of the seeds, the tallow is poured into a cylinder
made up of straw rings put one on the top of the other,
the whole placed in a rude press, and the tallow squeezed
through in a pure state.

The product is a hard, white, tasteless, odourless solid.
It chiefly consists of tri-palmitin. Its melting point is
about 104° F.

JAPAN WAI. — Although called wax, this substance is,
strictly speaking, a fat, as it consists of palmitin or gly-
cerin palmitate. The chief sources from which it is com-
mercially obtained are Ehus succedanea and Rhus verni-
cifera, which, according to Prof. J. REIN, of Marburg,
were introduced into Japan probably from the Loochoo
Islands.

According to A. MEYER,* the most usual plan for obtain-
ing the wax is the following : — The previously well-dried
fruits are ground either by mill-stones, or with wrooden
pestles in mortars, or by bamboo-flails. The shells and epi-
dermis are separated by sifting and winnowing, and the
mass is then heated in canvas bags over boiling water, in
order to melt the fat, which is then pressed out. The crude
tallow is now boiled with dilute lye, whereby it becomes
granular and more readily bleached. The bleaching by
sunlight and subsequent melting are repeated till the pro-
duct is pure and white. 400 Ib. of seeds will yield 100 Ib. of
wax. "When freshly broken, the fractured surface of the im-
ported article is almost white, or, sometimes, slightly yellow-

* " Year Book of Pharmacy," 1880, p. 220.

MATERIALS. 219-

ish-green. Its odour is like that of tallow, and disagree-
able. Its sp. gr. is 0.916 (MEYER), 0.99 (FIELD*), 0.984-
0.993 at I5° C. (ALLEN). It melts at 52-53° C. (125.6-
127.4° F.) (MEYER) when old, and about 42° C. (about
107.6° F.) when recently solidified. According to FIELD, its
melting point is 48.89° C. (120° F.). According to other
observers, its melting point varies from 120* to 130° F.
As it contains glycerin, it gives off the smell of acrolein
during combustion.

MYRTLE WAX (MYRICA WAX, MYRTLE TALLOW, OR BERRY
WAX) is a solid fat of a pale-green colour obtained by
boiling off the coating of the berries of Myrica cerifcra in
Louisiana, and of Myrica cordifolia at the Cape of Good
Hope. Its sp. gr. is 1.005, and its melting point 47-49° CL
(116.6—120.2° F.) (MOORE). It contains palmitic and my-
ristic acids, with a little glycerin, but its exact composi-
tion appears not to have been yet ascertained. Candles made
from this wax were exhibited at the Colonial and Indian
Exhibition, 1886, by Messrs. Hall & Zinn, of the Cape of
Good Hope. They burned with a smoky flame and with a
strong odour of tallow, but without guttering, f

PALM WAX. — From the trunk of Ceroxylon andicola. It
does not melt below the temperature of boiling water,
according to some observers, but according to others the
melting point varies from 161.6-186.8° F. (72-86° C.).

c. Mineral Waxes. — PARAFFIN is found native, or is
obtained by the distillation of petroleum, bituminous shales,
caniiel coal, lignite, wood-tar, or peat.J

jRefining Paraffin. — There are several methods practised

* Cantor Lectures on "Solid and Liquid Illuminating Agents, 'r
1883, p. 18.

f " Colonial and Indian Exhibition Reports, 1887," p. 276.

J For details of preparation, see " Oils and Varnishes," p. 153 et

220 CANDLES.

for effecting the purification of crude paraffin. In some of
these naphtha is used, in others it is dispensed with.

The following process is a combination of the action of
naphtha and hot-pressing, by which the quantity of naphtha,
which has a powerful solvent action on paraffin wax, is
much reduced : —

1. The crude solid is placed in a centrifugal machine, by
which paraffin oil is expelled.

2. The residual mass is cast into cakes, placed in layers
on cocoa-nut matting, on hollow iron plates containing water
to regulate temperature, and submitted to hydraulic pres-
sure. As much as possible is squeezed out in the cold, and
then the temperature is raised gradually to from 35° to
40° C., by which means the paraffins of lower melting points
.are squeezed out, the object being to produce a solid with a
high melting point, so as to make it approximate to the
character of wax or spermaceti. This operation leaves the
•cakes of a dark-brown colour.

3. To further purify these cakes, they are melted, heated
to 155° C., and 2 per cent, of sulphuric acid added, to
remove any bodies of the C11H2n series, or olefines, still
present.

4. The cakes are again melted with soda, cooled, and re-
pressed. They are then well washed with hot water, cooled,
mixed with cold colourless naphtha to assist filtration, and
then filtered through animal charcoal to remove colouring
matters.

5. The product is next placed in steam-jacketed wrought-
iron cylinders, and superheated steam is passed through to
remove naphtha. The residue is then pressed, and cast into
cakes.

Another way of carrying out the naphtha process is to
melt the scale with a certain proportion of naphtha. The
mixture is then either allowed to cool in suitable vessels, or

MATERIALS, 221

It may be cooled by artificial means. The cooled mixture
is subjected to hydraulic pressure, when the objectionable
portion is carried away by the naphtha. This operation is
repeated two or three times, or until the desired degree of
purity is obtained. Diagram A. (p. 222) will make the
process clear.*

In some refineries t the following method, called the
sweating process, is adopted: — The crude paraffin scale is
melted and heated to a temperature of 170-180° F., after
which it is allowed to repose until every trace of water and
separable impurity has settled out, the presence of which
would hinder crystallization. It is run into cooling pans,
which hold from i to 2 gallons ; these pans are generally
furnished with overflows, and are arranged as shown at A
(Fig. 39, p. 223). A stream of melted paraffin is directed into
the top pans by the taps b, and is continued until the whole
vertical series is full. They are then left to cool very slowly
in order to promote crystallization. When cold, the solid
cakes of paraffin are taken out of the pans and placed in the
ovens, which are fitted with shelves, the latter having a
slight inclination to the one corner, on which is laid a coarse
mat of cocoa-nut fibre to prevent the paraffin from being in
direct contact with the metal surface. The cakes are ex-
posed to heat until the desired degree of purity and melting
point is attained, the source of heat being a course of steam
pipes laid on the floor of the ovens. The portion that has
been fused out of the paraffin in the course of sweating is
again treated in the same manner, only at a lower tempera-
ture suited to its mean melting point. The drainings from
this latter cannot again be very profitably sweated, as they
contain the whole of the oil originally present in the scale,

* K. TERVET, " Journ. Soc. Chem. Ind." 1887, p. 356.
f "Journ. Soc. Chem. Ind." 1887, p. 356.

222

CANDLES.

,2ft
1°

'"^

tfg.

•a^

o3 OO

•S =

3/^\ I

IpK

s^r

MATERIALS.

223

224 CANDLES.

and also the greater proportion of paraffins of low melting
points. It is therefore cooled in a separate series of pans,
and then hydraulic-pressed to get rid of the oil. The solid
pressed paraffin obtained is either returned to the next make
of crude scale, or it may be finished off separately as a low
melting-point wax (mean melting point 102° F.). It is usual
to allow a certain proportion of the paraffin of intermediate
melting points to pass to this stage, in order to give solidity
and maintain a suitable melting point for the finished
product.

Diagram B. (p. 225) gives in outline the several stages of
this process.*

An improvement in the above method, designed to econo-
mize labour, is described by K. TERVET.t By reference to
Fig. 39, it will be seen that the coolers are set directly above
the cells in which the sweating is conducted. The cooling
and sweating cells may be made of any convenient size —
they may be 3 feet broad by 6 feet high. The way in which
the coolers are sealed at the bottom is made to depend upon
the shape in which the alternate strips of soft wood and
iron, or soft and hard wood, are placed, and which extend
right across the lower openings. It is evident when pres-
sure is applied by screws, or otherwise, to the side A, which
forms the end of the system, the strips of soft wood, which
go to cover the openings of the cells, will rise slightly, while
the iron strips, which cover the blank spaces between, will
correspondingly fall.

In practice this arrangement is found more than sufficient
to seal the openings of the coolers.

To empty the coolers it is only necessary to relax the
screws, 6, and draw forward the strips of wood when the

* K. TEBVET, " Journ. Soc. Chem. Ind." 1887, p. 357.
f Hid.

MATERIALS.

225

i ~

P-1 v^x O

1 -*

1 .si

ij Sj S

^ c

5 .^5

f ^

X-"%

'«N ^^

S 6 ? ?

I f|l|2

PQ o:

? illlS

DIAGRAM

— WAX— MJ

1 Jlp*

gj s "S 5 S P

•a 1

<? s-

S 'S

"i &

w ^

9,^

cot

.226 CANDLES.

cooled paraffin cakes are free to descend into the sweating
cells, after which the strips are pushed into their place and
the screws tightened, when the cells are again ready to be
filled. In order to facilitate the dropping of the cakes from
the coolers, a very slight taper is put upon them, which
need not be more than T\th inch per 1 2 inches in height.
The distance between the coolers and the sweating cells is
less than the height of the cell.

The sweating cell, B, is constructed of wire netting or
perforated sheet metal, inside which is hung a coarse woven
cloth of any description, but preferably of woollen plaiding.
On the top of the cell there is set a light iron casting which
forms the entrance, and assists in keeping it in position.
At the bottom there is another casting, c, with an opening
the same size as the cell, the edges of which are turned up
all round, both inside and outside, forming a channel gutter,
which is provided with an outlet leading to d. The cell is
set within this channel, and, as the cloth extends to the
bottom, the liquid portion fused out of the paraffin is con-
ducted to the channel by the capillarity of the cloth. In
order to prevent the solid cake from falling through the
lower opening, there is provided a sliding door, e, of thin
sheet-iron, the sides of which are turned down and overlap
the inner sides, covering them like a lid. The passage for
the edges of the door is therefore between the inner sides
of the gutter and the cloth. This gives direction to the
liquid portion, and effectually hinders any part of it from
finding an outlet other than to the gutter.

In adapting this apparatus for a continuous or fraction-
ating process, it is necessary to have two or more sweating
cells in height, and a proper means of regulating the tem-
perature. All the parts and arrangements remain the
same as described, only the doors in the upper cells may, if
thought proper, be dispensed with, as the paraffin', in its

MATERIALS.

227

plastic condition, moulds itself to the irregularities of the
cell, and effectually stops any passage to the cell beneath.

Suppose such an arrangement be constructed as shown,
in Fig. 40, and that the temperature is under proper
control. It is evident that the greater portion of the
impurities will be drained away in the first or uppermost
cell, and that the cake will have correspondingly diminished
in bulk before passing to the second or middle cell, where

FIG. 40.

the soft, and intermediate soft, paraffin would be sweated
out. Again, on passing to the third cell, the cake of
paraffin will not be more than 65 per cent, of its original
bulk, but containing all those hard intermediate fractions
which correspond to the once sweated scale (No. 3) of
Diagram B. (p. 225), and which, after further sweating,
$nd when the proper melting point has been attained, may
be discharged by withdrawing the bottom door. There is
no danger of the partially sweated paraffin falling out, as its

• Q2

228 CANDLES.

descent is only gradual ; indeed, one important feature of
the arrangement — either as a simple or complex structure —
is that the cake will not come out until it is perfectly
sweated, which is only attained at a temperature which,
if prolonged, would result in the complete fusion of the
paraffin.

The advantages claimed by the author of this process are
— (i) that the sweating, being obtained simultaneously from
both sides of the paraffin, permits of the operation being
carried on at a comparatively low temperature, and with
greater rapidity. (2) The cakes can be made of greater
thickness than by the usual method. (3) The process can
be made continuous by duplicating, vertically, the cells in
which the sweating is conducted. This is obtained by taking
advantage of the gradual diminution in bulk which the
paraffin undergoes in the course of sweating. Although
this latter advantage effects no great economy, yet it makes.
the production of the full proportion of first-class wax
obtainable from crude scale at one operation a possibility.
(4) In working with an apparatus constructed of three
cells, it can be charged and discharged every four hours,,
beginning with a scale of melting point 112-114° F., and
finishing with a wax melting at 126° F. As the drippings
are separately fractionated out in three grades of purity, it
facilitates their subsequent treatment to have them always,
of a uniform composition and melting point.

FORDRED* purifies crude paraffin by melting, leaving-
mechanical impurities to settle down, and then transferring-
to smaller vessels to cool. The cakes are next warmed till
they become kneadable, and are then washed with a solution
of 10 parts of soft soap in 90 parts of water, and heated
to about 38° C. Colouring matters and any oils that

* " Monit. scien." [3], iii. 826.

MATERIALS. 229

may be present are transferred by this treatment to the
soap water, and the solid paraffin comes out purified and
bleached.

Pure Paraffin is a colourless, inodorous, tasteless solid. Its
sp. gr. is from 0.870 to 0.909 at 15° C. It melts at 113—
149° F. (45-65° C.). It becomes plastic much below its
.melting point — a disadvantage which is corrected when
used for candles by admixture with bees'-wax or stearic acid.
It is insoluble in water, and only slightly so in alcohol. Sul-
phuric and nitric acids and chlorine are without action upon
it in the cold. Chlorine passed through melted paraffin
slowly attacks it with evolution of hydrogen alone. This
last reaction establishes its position among members of the
marsh-gas family. It surpasses all other candle materials,
-even spermaceti, in illuminating power.

Methods of taking the Melting Point of Paraffin. — The
•so-called melting point (which is really the setting point)
of paraffin is, in the case of the recognized American and
English methods of making the test, the temperature at
which the sample, after having been melted, and while in
the process of cooling, begins to solidify.

The AMERICAN test is conducted by melting sufficient of
the sample to three parts fill a hemispherical dish 3 J inches
in diameter. A thermometer with a round bulb is sus-
pended in the fluid so that the bulb is only three-fourths
immersed, and, the material being allowed to cool slowly,
the temperature is noted at which the first indications of
filming, extending from the sides of the vessel to the ther-
mometer bulb, occur.

The ENGLISH test is performed by melting the sample in
a test-tube about J inch in diameter, and stirring it with a
thermometer as it cools until a temperature is reached at
which the crystallization of the material produces enough
lieat to arrest the cooling, and the mercury remains sta-

230 CANDLES.

tionary for a short time. The results afforded by this test
are usually 2^° to 3° F. lower than those furnished by the
American method.

The melting point is also sometimes determined by ob-
serving the temperature at which a minute quantity of the
sample, previously fused into a capillary tube and allowed
to set, becomes transparent when the tube is slowly warmed
in a beaker of water.*

OZOKERIT (FossiL WAX, EARTH WAX). — This remarkable
mineral, which has been utilized as a candle material by
Messrs. Field, of Lambeth, is found in various localities in
the Tertiary strata, mostly occurring in, or in close proximity
to, the coal measures. The largest and purest deposits
are found at Drohobycs and Boryslaw in Galicia, on the
slopes of the Carpathians, in the island of Tcheleken in the
Caspian Sea, and elsewhere, but it is by no means an
abundant substance. It is obtained partly on the surface-
and partly by mining. A body very similar to ozokerit,
called Neft-gil, is found on the island of Swatoi-Ostrow in
the Caspian Sea.

Ozokerit is usually met with as a compact brown sub-
stance, occasionally yellow, sometimes black. It melts at
about 60° C. (140° F.). It can be made to yield, by proper
treatment, 80 to 90 per cent, of paraffin (FIELD).

Refining Ozokerit. — To obtain products from the mineral
which can be used commercially, several processes are
described by FIELD :f —

i. The most largely employed method is that of treating
the crude wax with Nordhausen sulphuric acid, and heat-

* BOVERTON REDWOOD, "Jour. Soc. Arts," 1886, p. 896.
f Cantor Lectures, " Solid and Liquid Illuminating Agents,"-
January, February, and March 1883, p. 45.

MATERIALS. 231:

ing it till the acid has become decomposed. After proper
decolorizing, the wax assumes a golden-yellow colour, and in
appearance much resembles bees'-wax. It is called cerasin
from this resemblance, and can be brought to almost a
pure white. In this state it is not of much use for candle-
making, as it has a strong and unconquerable tendency to

smoke.

•i

2. UJHELY dissolves the crude material in benzine, or
some other spirit, in which condition it can be readily filtered
through charcoal. The spirit is then distilled off in an air-
tight apparatus, leaving the white paraffin behind.

3. At Messrs. Field's works, Lambeth, the crude ozokerit
from Galicia is distilled in a current of superheated steam,
and the following distillates are obtained : —

(1) A gaseous hydrocarbon, to the extent of about

5 per cent.

(2) A volatile naphtha, about 3 per cent.

(3) A product resembling vaseline, termed ozokerine,

about 6 per cent.

(4) A soft 2iaraffin, melting at 112.1-115° ^\ (44- 5~

46.1° C.).

(5) A white paraffin (ozokerit), about 70 per cent.

Melting point, 141.8° F. (61° C.).

(6) A black residue, melting at 170.6° F. (77° C.).
No use has yet been found for products (i) and (2).

(3) is used as a substitute for vaseline.

(4) is used for cheap candles.

(6) is used by electrical engineers as an insulating
material.

STEARIN. — We have seen (p. 210) that tallow consists
mainly of a mixture of the glycerides called stearin and
olein, the former solid and the latter liquid at common
temperatures. Common tallow melts at between 99° and

232 CANDLES.

104° F. (37-40° C.), while the melting point of stearin is
144° F. (62° 0.). Hence, by the removal of a consider-
able portion of the olein from the tallow, the fusing point
of the latter is considerably raised, and its character as a
candle material much improved. In the laboratory experi-
ments of CHEVREUL, this separation was effected by means
of solvents, but it w.as soon found that, by attending to the
temperature of the fat, it might, for all practical purposes,
be produced equally well by pressure. If tallow is melted,
and allowed to cool as gradually as possible, with constant
agitation, the mass becomes pasty, and by slow pressure in
cloths the olein is squeezed out. By repeating the operation,
the stearin is obtained gradually of greater purity.

Candles made of this pressed tallow fairly deserve to be
called stearin candles, but stearin is now seldom thus pre-
pared, and the so-called stearin candles consist really of more
or less pure stearic or palmitic acid.

COCO-STEARIN. — A patent was taken out by SOAMES in
1829* for making stearin and olein by the following pro-

Cocoa-nut oil as imported is submitted to strong hydraulic
pressure, having been made up into small packages 3 or 4
inches wide, 2 feet long, and i or ij inch thick. These
packages are formed by first wrapping up the cocoa-nut oil
in a strong linen cloth of close texture, and then in an ex-
ternal wrapper of strong sail-cloth. The packages are then
placed side by side, in single rows, between the plates of the
press, allowing a small space between the packages for the
escape of the olein. The temperature at which the pressure
is begun should be from about 50° to 55° F.,or, in summer,
as nearly as this can be obtained, and the packages to be

* No. 5842.

MATERIALS. 233

pressed should be kept for several hours previously at about
the same temperature. When the packages will no longer
yield their olein freely, the temperature is to be gradually
raised, but it must at no time exceed 65° F., and the lower
the temperature at which the separation can be effected
the better will be the quality of the expressed oil.

When the packages have been sufficiently pressed — that
is, when they will give out no more oil, or yield it only in
drops at long intervals — the residuum in them is to be taken
out and purified. This is done by melting it in a well-
tinned copper vessel, which is fixed in an outer jacket, so as
to leave a vacant space closed at the top between them, into
which steam is admitted, and a moderate heat is kept up
for a sufficient time to allow the impurities to subside. If
a still higher degree of purity is required, it is necessary to
pass it through filters of thick flannel lined with blotting-
paper.

Thus cleansed, the coco-stearin is fit to be used in the
ordinary process for making mould tallow candles.

The second product of this operation, or olein, is purified
as follows : — It is mixed with i or 2 per cent, by weight,
according to the degree of its apparent foulness, of the sul-
phuric acid of commerce, of about sp. gr. 1.80, diluted with
six times its weight of water. The whole is then subjected
to violent agitation by mechanical means, conveniently in a
vessel constructed on the principle of a common barrel
churn. When sufficiently agitated, it will have a dirty-
whitish appearance, and is then drawn off into another
vessel, in which it is allowed to settle, and any scum that
afterwards rises is carefully removed. In a day or two the
impurities will subside,' and the clear oil is then filtered
through thick woollen cloth, and will be suitable for burning
in ordinary lamps, and other purposes.

234 CANDLES.

4. Fatty Acids.

History. — The obstacles which stood in the way of the
employment of tallow stearin might possibly have been re-
moved, but the researches into the nature of the process of
the saponification of fats, resulting in the separation of solid
acids from the fatty bodies, directed the inquiry into another
channel. When it was found that stearic acid fusing at
158° F.] (70° C.) could be obtained from stearin fusing at
144° F. (62° C.), while the oleic acid remained as fluid as
the olein from which it was derived, it became evident that,
as the difference in the fusing points of the solid and liquid
acids is so much greater than that between the stearin and
the olein, their separation might be affected with less diffi-
culty. Thus the transition from the tallow candle to the
stearic candle was effected.

Though CHEVREUI/S researches were published in 1823, it
was not till two years afterwards that the idea of making
candles from the isolated fatty acids was matured. In 1825
CHEVREUL and GAY-LUSSAC took out a patent in France for
the manufacture of fatty acids and their application to the
manufacture of candles. On the Qth of June 1825, GAY-
LUSSAC, in the name of his agent, MOSES POOLE, also took
out a patent in England. These patents are remarkable as
specifying the distillation of fatty acids with the aid of
steam, and the use of lime for the saponincation of the fat.
The distillation by steam was not practically applied until
sixteen years after this date, and, instead of lime, the alkalies
potash and soda were employed by the patentees for accom-
plishing the saponincation, and hydrochloric acid was used
to decompose the soap, producing alkaline salts which were
never completely separable from the fatty acids.

It is well known that CHEVREUL and GAY-LUSSAC'S patent
was not commercially successful ; the processes which they

PREPARATION OF THE FATTY ACIDS. 235

employed resembled too closely laboratory experiments, and
the industrial execution proved too costly.

Where these illustrious chemists failed, DE MILLY suc-
ceeded by introducing the cheaper material, lime, as the
saponifying agent, and decomposing the lime soap formed
by dilute sulphuric acid. The lime saponification process,
on a commercial scale, dates from the year 1831.

Preparation. — We may consider the modes of preparing
the fatty acids under the five following heads : —

I. Lime Saponification.
II. Acidification.

III. Dissociation by Heat.

IV. "Autoclave" Process — a combination of the

first and third methods.

V. Bock's Process — a modification of the second
method.

1. Lime Saponification Process. — i. Melting. — Into a
large wooden vat (under lime tub,^., Fig. 41, p. 238), contain-
ing a coil of steam-pipes pierced with small holes, a quan-
tity of tallow, or of tallow and palm oil (about 3 parts of the
former to i or i j of the latter*), is emptied from the original
casks, together with a quantity of water. The steam, when
turned on, enters through the holes into the water, raises
its temperature, and melts the fat.

2. Saponification. — As soon as the water has entered into
ebullition, a quantity of slaked lime, equal to from 10 to
15 parts of dry quicklime for every 100 parts of fat, accord-
ing to the nature of the fat used, is added.f It is important

* The acids from tallow alone are often not sufficiently /crystalline
to admit of thorough pressing. The products from a mixture of
tallow and palm oil are superior to those from either fat alone.

f According to theory, 100 parts of fat would require only 8.7
parts of caustic lime, but the excess of lime renders saponification

236 CANDLES.

that the lime should be caustic, and as pure as possible. If
not entirely caustic, a larger proportion will be necessary to
thoroughly decompose the fat, and more acid will be after-
wards required to remove it. If the impurities are con-
siderable, they may become insoluble, and difficult to
separate afterwards from the mixed acids. The vat having
been tightly closed, the boiling is continued for about six
hours, or until complete saponification is effected, which is
-ascertained by drawing out a small portion of the boiling
mixture in a ladle. This, when cold, should appear perfectly
smooth and solid, and should be very brittle, powdering
finely in a mortar. During the boiling, the mixture is kept
in constant agitation by means of a wooden shaft, furnished
with horizontal arms, and worked by steam. At the end of
the operation, the fatty acids will have combined with the
lime to form a lime soap, called rock, which is, chemically,
.a mixture of stearate, palmitate, and oleate of lime. The
whole is allowed to cool in the same vessel, and the liquid
portion, containing 5 to 1 5 per cent, of glycerin, and termed
sweet-water, is run off, and may then be evaporated down to
.about one-fifth of its bulk, yielding crude glycerin of about
sp. gr. 1.26.

3. Decomposition. — The lime soap, orroc/c, is next dug out
from the saponifying tank and removed to the lead-lined
separating vat, B, which is also furnished with a perforated
.steam coil. Here the rock is separated into calcium sulphate
and fatty acids. When the boiling point is reached, sul-
phuric acid (the ordinary brown acid of commerce), pre-
viously diluted, is added in the proportion of about 25 parts
of the strong acid to every 100 parts of fat, and the boiling
.and agitation are continued. The acid may be added in
successive portions till the workman sees, by the appearance
of the mass, that a sufficient quantity has been introduced.
It rapidly combines with the lime, forming insoluble calcium

P RE PAR A TION OF THE FA TTY ACIDS. 237

sulphate, and liberating the oily acids, which float on the
surface, and are called yellow matter. When partially cool,
this yellow matter is either run off by cocks, placed at the
proper level, or pumped into the washing vat, C.

4. Washing. — In this vat the acids are washed at a high
temperature by means of steam and water, first mixed with
very dilute sulphuric acid, and afterwards with water only.

5. Caking. — The washed fatty acids are then removed to-
flat tin pans, or caking tins, D, and left at a temperature
of 68° to 86° F. (20° to 30° C.), for two or three days, or
until they have solidified with a granular or crystalline
structure.

6. Cold^yressing. — The cakes are next placed in bags of
cocoa-nut matting or horsehair, and introduced into the
hydraulic press, E, which at first is worked very gently.
The bulk of the oleic acid is thus removed, and the cakes
assume a light-yellow, instead of their original dark-brown,
colour.

7. First Refining. — The cold-pressed cakes, as they are now
called, which still contain about 10 per cent, of oil, are re-
melted by steam in a lead-lined wooden vat, G, with a little
dilute sulphuric acid to remove the last traces of lime, oxide
of iron, or other impurity. The melted material is then
placed in flat tin trays, and again allowed to cool (at a
slightly higher temperature than in the previous cooling)
and solidify.

8. Hot-pressing. — The cakes, thus further purified, are now
placed in stronger bags, conveniently made of goats' hair,
introduced into the horizontal hot press, H, and subjected
to great pressure at a high temperature for about two hours.
By this operation the remainder of the oleic acid, holding a
little of the solid acid in solution, is removed. The pressed
cakes retain a small quantity of oleic acid at the edges;
these are therefore scraped off, raeltsd, and again pressed.

238 . CANDLES.

9. Second Refining. — The refined cakes are now placed in
the melting vat, /, and heated by steam, a little wax being
sometimes added at this stage to destroy the crystalline

PREPARA TION OF THE FA TTY A CIDS. , 239

texture of the stearic acid. The material is afterwards cast
into blocks.

The final product is a mixture of impure stearic and pal-
mitic acids, having a melting point of 132—135° F.

The lime process admits of the use of very impure fatty
materials.

MODIFICATION OF THE LIME PROCESS BY MOINIER AND
BOUTIGNY.* — 2 tons of tallow are introduced with 900
gallons of water into a rectangular vat of about 270 cubic
,feet capacity.

1. Melting. — The tallow is melted by means of steam ad-
mitted through a pipe coiled round the bottom of the vat,
and the whole kept at the boiling point for an hour, during
which a current of sulphurous acid is forced in.

2. Saponification. — At the end of this period 6 cwt. of
lime, made into a milk with 350 gallons of water, are added.
The mixture soon acquires some consistence, and becomes
frothy and very viscid. The whole is now agitated in order
to regulate the ebullition and prevent the sudden swelling
up of the soapy materials. The pasty appearance of the
lime soap succeeds, and it then agglomerates into small
nodular masses. The admission of sulphurous acid is now
stopped, but the injection of the steam is continued until
the small masses become hard and homogeneous. The
whole period occupies eight hours, but the admission of the
sulphurous acid is discontinued at the end of about three
hours. The water containing the glycerin is run off from
below by a tube to a large underground cistern.

To prepare the sulphurous acid, sulphuric acid and pieces
of wood are introduced into retorts, which are heated by
fire. The sulphurous acid which passes off is conveyed by
leaden pipes to the vessels containing the tallow, where the

* RONALDS and RICHARDSON, " Technology," vol. i. pt. ii. p. 437.

240 CANDLES.

saponification is effected under the joint influence of the
acid and steam.

3. Decomposition. — The lime soap formed is moistened
with 12 cwt. of sulphuric acid at 152° F., diluted with 50
gallons of water. The whole is thoroughly agitated and the
steam cautiously admitted, so as not to dilute the acid too
much until the decomposition is general at all points. This
occupies about three hours, and in two or three hours more
the calcium sulphate has collected at the bottom, while the
fatty acids float on the surface of the solution of bisulphate
of lime.

4. Washing. — Washing with steam and water is afterwards
necessary to remove the adhering portions of calcium sul-
phate, &c., and, after settling for four hours, the fatty acids
are forced through a fixed siphon into a vat, where they
are again washed with water. They are then a third time
washed with water, and siphoned at last into a trough lined
with lead, on the bottom of which are placed leaden gutters
pierced below by long pegs of wood.

5. First, or Cold, Pressing. — .The cakes of fatty acids are
inclosed in bags of flannel, and pressed in the cold in a
hydraulic press. The oleic acid, squeezed out, is conveyed
into a washing cistern. It is important to allow the fatty
acids to cool slowly, so as to prevent a too confused crystal-
lization, and to facilitate the expulsion of the oleic acid.

6. Second, or Hot, Pressing. — The cakes are now placed
between horsehair sacks, and submitted to a second pressure
at a high temperature. The whole is covered with oil-skin,
and the temperature raised to 158.5° F. (70° C.) when the
pressure is applied. The heat slowly falls to 113° F.
(45° C.), and ultimately to 95-86° F. (35-30° C.). This
second pressing occupies about an hour. The oleic acid
obtained contains large quantities of stearic and palmitic
acids.

PREPARATION OF THE FATTY ACIDS. 24!

7. Sorting. — The cakes of the stearic acid are sorted
according to colour and translucency.

8. Refining. — 20 cwt. are introduced into a vat, con-
structed of wood lined with sheet-iron. The materials are
boiled by steam admitted through a leaden pipe. Water
acidulated with sulphuric acid is first employed, and after-
wards water alone. When the materials are boiling, the
white of twenty-two eggs is introduced, and the albumen is
intimately mixed by the violent ebullition. As soon as the
albumen is coagulated, the mass is allowed to cool, but is con-
stantly agitated so as to prevent the formation of crystals.

MOINIER and BOUTIGNY considered that the use of sul-
phurous acid increased the yield of acid by about 4 per cent.,
the calcium sulphite formed, when treated with sulphuric
acid, yielding sulphurous acid, which destroyed the nitrous
acid contained in the sulphuric acid employed, which,
otherwise, acted upon the fatty acids, and lessened their
amount.

II. Acidification and Distillation Process. — History.
— It was known to ACHARD in the year 1777 that neutral
fats are decomposed by concentrated sulphuric acid in a
manner similar to the decomposition effected by caustic
alkalies. This fact was again brought forward in 1821 by
CAVENTON, and in 1824 by CHEVREUL, but was not scientifi-
cally investigated till 1836 by FREMY. Both sulphuric acid
and the alkalies decompose the fats, but, while the alkalies
combine with the fatty acids and liberate the glycerin, the
sulphuric acid, it was thought, combined with both, pro-
ducing from the acids of the fat, sulpho-stearic, sulpho-
palmitic, and sulph-oleic acids, and from the glycerin, sul-
pho-glyceric acid.*

* It will be seen on p. 250 that Dr. BOCK does not agree with this'
view of the reaction.

242 CANDLES.

GEORGE G WYNNE, in March 1840, appears to have described
for the first time a method of obtaining fatty acids by
the treatment of neutral fats with sulphuric acid and sub-
sequent distillation of the resulting products. The proposal
was to distil in vacua by means of an apparatus similar to
that used in sugar-refining, but the working was not found
practicable owing to the difficulty of maintaining a good
vacuum on the large scale.

In November 1840, GEORGE CLARK took out a patent for
utilizing this property of sulphuric acid in decomposing fats,
but without subsequent distillation. This also was found
unworkable, owing to the grea,t cost of purifying the fat
after decomposition.

In August 1841, DUBRUNFAUT obtained a patent in
England, and, about the same time, another in France, for
the purification of fatty bodies and their distillation. The
chief object of this patent was the purification of the com-
moner oils by heating them to a high temperature and then
passing steam, through them. In this way their disagree-
able odours were to be removed. But the distillation of
fatty bodies was also claimed.

In 1842, Price & Co., under the name of WILLIAM COLEY
JONES, patented the process of distillation of acids from
cocoa-nut oil alone, and also after saponification with lime.
The candles made from the first product were objectionable
on account of the unpleasant vapours evolved, while the
candles made of the product of the distillation of the cocoa-
nut lime soap, though satisfactory, were too costly.

On December 8, 1842, a patent was obtained by WILLIAM
C. JONES and GEORGE WILSON for decomposing fats with
sulphuric acid, aided by heat, and distilling the fat, thus
decomposed, by means of steam. This is the first successful
application of the combined processes of acidification and
steam-distillation.

PREPARA TION OF THE FA TTY ACIDS. 243

A patent, dated December 28, 1843, by GWYNNE and
WILSON, describes a method of reducing the quantity of
sulphuric acid employed for decomposing the fats to from
10 Ib. to 6 Ib. for every cwt. of fat. This saving was
effected by heating the fat to 350° F. (177° C.). Another
improvement was the heating of the steam in a series of
pipes after it had left the boiler, instead of depending on
the temperature of the fat to effect it.

By a subsequent patent, dated October 30, 1844, GWYNNE
and WILSON proposed to use a jet of superheated steam to
heat the fats previous to sulphuric saponification.

The following are the details of the process as now
ordinarily practised : —

1. Melting. — The fat to be operated upon is melted from
the casks by means of a steam-jet inserted in the bung-hole,
and is then run into the underground tank, A, Fig. 42 (p.

245)-

2. Soiling. — The lead-lined tank, B, is one of a series into

which, after settling in the tank A for some hours to sepa-
rate the condensed water and grosser impurities of the fat,
the melted fat is raised by means of the force-pump, C.
In. these vats, which are fitted with steam coils, the material
is boiled.

3. Acidifying. — The fat is next pumped into the vessel Dt
-called the acidifier. This is constructed of stout copper,
and supported either on wrought-iron girders or brickwork.
It has the following fittings — viz., A valve with pipe for
the admission of superheated steam ; a copper pipe, fitted
with a water shower-pipe, cZ, for condensing the generated
vapours ; a thermometer for the guidance of the operator ;
and a gun-metal cover at the lower side, for cleaning out,
to which is affixed a cock by means of which the acidified
materials are drawn off. After its introduction into this
vessel, the fat is heated by the admission of superheated

B, 2

••244 ; CANDLES.

steam at 350° F. (176° 0.)* from the superheater, F (the
design of Mr. EDWARD FIELD, C.E.), and then sulphuric
acid, in the proportion of about i to ij cwt. per ton of fat,
is run in from the add tank, E, above.t The fat is decom-
posed and becomes much blackened, the glycerin being con-
verted into sulpho-glyceric acid, with evolution of sulphurous
acid, and at the same time any foreign organic matter in
the fat is carbonized, with evolution also of sulphurous
fumes. The neutral fat is converted into a mixture of
sulpho-fatty acids and sulpho-glyceric acid. The whole
operation may take from fifteen to twenty hours, and when
the acidification is complete the contents of the vessel are-
allowed to rest for from four to six hours.

4. Washing. — The materials are next discharged into a
series of lead-lined washing vats, G G, previously filled ix>
about one-third with water, containing a little sulphuric acid.
The vats are furnished with copper steam coils, and the
-contents are boiled with free steam for two hours, and then
left to settle for about twenty-four hours.

5. Distillation. — The fatty acids are then drawn off from
the vats G G into the tank^, from which they are pumped
through the tap c into the lead-lined charge tank, H, above
the still. Inside this tank is a steam coil, which is charged
with steam at the time the acids are admitted, in order to
keep them liquid. From this tank the material is run into
the still, /, of which the body is made of iron and the dome
of copper. The distillation requires several precautions-

* This is the temperature employed at Price's works, Battersea.
At the works at Gentilly, near Paris, the heat is seldom higher than
from 110° to 115° F.

f The proportion of sulphuric acid depends upon the nature of
the fatty materials employed. Kitchen-stuff, slaughter-house fat,,
and the like require about 12 per cent, of their weight ; palm oil»
jfrom 5 to 9 per cent., according to quality.

PREPARATION OF THE FATTY ACIDS. 24$

246 CANDLES.

with an open fire the fatty acids are apt to be converted into
oil, tar, and a carbonaceous residue, if the heat is too high*
Air should be also completely excluded from the apparatus.
The contents of the still are heated by the fire underneath
to about [240° F. (116* C.) and then low-pressure super-
heated steam, at about 560° F. (293.3° C.), is admitted by
a pipe from the superheater (shown on the left of the still in
the illustration). The process of distillation then begins.
The current of steam carries with it the vapour of the fatty
acids, and thus facilitates the process. The mixed vapours,
pass to a series of vertical refrigerating pipes, K. These are
of copper, connected at top and bottom by gun-metal bends,
mounted on iron frames, and set over the series of iron
tanks k, containing copper cooling coils, through which cold
water can be passed, and also furnished with steam pipes..
L is the essence tank, fitted with a safety condenser, or
shower pipe, which prevents the possibility of any vapour
passing away uncondensed. M is a pipe for conveying gas
to be burnt in the flue.

The fatty acids as they run from the still are, to a great
extent, available for candle-making without pressing, but
other portions are subjected to pressing, sometimes both
cold and hot, and often to a second distillation.

Out of every 100 Ib. of tallow subjected to this process
it is stated by W. LANT CARPENTER* that about 78 to
80 Ib. of crude stearic acid are produced, of which 60 lb.r
or three-fourths, are ready for making stearin candles with-
out further pressing. The remaining one-fourth, after being
pressed and re-distilled, yields} about 15 Ib. more stearic
acid and 5 Ib. of oleic acid.

The residue is a sort of pitch, and is transferred, before it
solidifies, to a vessel of iron, where it is submitted to a muck

* SPON'S " Encyclopaedia," p. 582.

PREPARA TION OF THE FA TTY A CIDS. 247

higher temperature and a jet of steam more strongly heated.
An additional quantity of fatty acids is thus obtained, of
inferior quality, but applicable to the ; preparation of com-
posite candles. The final residue is used for many purposes
in the same way as ordinary pitch.

The following is a brief description of Fig. 42 (p. 245) : —

A is the melting tank. B is one of a series of lead-lined
boiling tanks. C is the force-pump. D is the " acidifier."
E is the acid tank. F is the superheater. G G G G are the
washing vats. H is the charge tank. / is the still. K is
the refrigerator, k, one of the series of iron tanks con-
taining the copper cooling coils. L, the essence tank. J/, a
pipe for conveying gas to the flue.

III. Dissociation by Heat. — This may be effected either
by the high-pressure process, or by superheated steam at
ordinary pressures. The first was patented in 1854 by
TILGHMANN, and its object is the separation of fats into
acids and glycerin by heating with water only, under pres-
sure, by which, at the same time, the substances are, to a
certain extent, bleached. The method consisted, briefly, in
pumping the mixture of fat and water through a coil heated
to above 800° F., and at a pressure of about 2000 Ib. to
the inch. This operation was attended with considerable
risk.

The second method was suggested to WILSON and PAYNE
by the above, and was patented by them in the same year.*
It is conducted as follows : — The fatty matter is heated in
a still to about 550-600° E. (290-315° C.). Superheated
steam, at a temperature of 600° F., is injected in such a
way that it rises up through the molten fat in numerous
streams. Saponification is thus effected, and the liberated
fatty acids and glycerin are volatilized, and carried over

* No. 1624 — 1854.

248 . CANDLES.

in an atmosphere of steam to the condensing arrange-
ment.

If the temperature is too high (above 600° F.), there is
a great liability (diminished, however, by a very plentiful
supply of steam) that the fatty acids and glycerin will be
further decomposed — gaseous hydrocarbons, acrolein, and
tarry matters being produced. On the other hand, if the
heat is insufficient, either the separation of the glycerin is
imperfect, or proceeds too slowly.

When the refrigerating arrangement consists of a series
of chambers, each provided with a cock to draw off the dis-
tiljates, and each more and more distant from the still, the
compartments nearest to the still are found to condense
little but fatty acids, being for the most fpart free from
water and glycerin, which chiefly accumulate in the more
distant and cooler condensers. In all the receivers the fat
acids quickly separate from any aqueous solution of glycerin
present, when allowed to cool for a little time. The last of
the condensing chambers is open to the air, as no pressure
is necessary in this apparatus. By simply evaporating off
the water, very pure glycerin is obtainable.

IV. The "Autoclave" Process. — The large amount
of lime required in carrying out the lime saponification is
attended with the disadvantage that the great quantity of
sulphuric acid necessary for the decomposition of the result-
ing rock injuriously darkens the fatty acids produced. By
a combination of the lime saponification and TILGHMANN'S
high-pressure processes, DE MILLY, in 1856, found that the
proportion of lime could be reduced to 2 or 3 per cent.,
while a less pressure also was sufficient to effect the decom-
position. This is called the autoclave* process. The fat is

* From atfrds, self, and /cXets (Lat. clavis), a key = that which shuts
itself. It is a Papin's digester with a steam-tight lid fixed perpen-
dicularly, and is preferably furnished with a safety valve.

PREPARATION '. OF THE FATTY ACIDS. 249

put into a strong boiler provided with a stirrer, and mixed
with 3 per cent, of slaked lime. Superheated steam is
passed in till the pressure equals 160 to 180 Ib. on the inch.
After some three hours at this pressure, the separation is
complete, and when the exit pipe is opened the fatty acids
are forced out. A very small amount of sulphuric acid is
afterwards needed to free them from lime. In twenty-four
hours three operations of 2 or 3 tons each may be completed.
The subsequent treatment for the crystallization of the
fatty acids, cold- and hot-pressing, &c., are the same as in
the other methods.

The fatty materials submitted to the autoclave process
should be of good quality.

V. Bock's Process. — In 1871 Prof. BOCK, of Copen-
hagen, pointed out that the neutral fats are composed of a
congeries of little globules enclosed in envelopes, probably
albuminous. To the presence of these in the fat he attri-
buted the difficulty of eliminating the fatty acids by means
either of sulphuric acid, except in excess, or of alkali, except
under great pressure, conceiving that both these agents, as
ordinarily employed, are to a great extent expended in
rupturing and destroying the albuminous envelopes.*

CARPENTER \ gives the following synopsis of Dr. BOCK'S
process, extracted from " Dingler's Poly tech. Journ." May
1873:—

" By the lime saponification plan, the albumen contained
in the fat is dissolved, lime soap is formed, and the extrac-
tion of the glycerin is rendered possible. By acidification,
the whole process is effected at once. Conducted properly,
the fat, washed out with water, always remains as a neutral
fat, and, by the use of concentrated sulphuric acid, not a

* COOLEY'S " Encyclopaedia," ii. 1557.
f SPON'S " Encyclopaedia," p. 583.

250 CANDLES.

trace of glycerin is left. Acidification, rationally conducted,
is only a preliminary operation, intended to break up, cor-
rode, or carbonize the albuminiferous matters. But the
operation was long based on the erroneous belief that a
double acid, sulpho-stearic, was formed. With due care,
only the envelopes of the cells are blackened, and these are
soluble neither in fat nor in fatty acids. The production
of a real black solution is only an evidence that a certain
part of the fat has been charred, which should be avoided
under all circumstances. There is no doubt that the
operation has generally been carried to excess in the matters
of duration, height of temperature, or strength of acid. By
proper acidification, the neutral fat is only unclothed, as it
were, and freed from the cells, or, at any rate, the latter are
so ruptured as to allow of the easy exit of the fat. This
latter is then in a condition to be decomposed, an operation
accomplished in a much shorter time by the chemical
equivalent of acid — 4 to 4.5 per cent. — and the necessary
water. After letting out the glycerin waters, the fatty
acids appear more or less black. They may now be dis-
tilled. Their melting point varies from 120° to 134° F.
(49° to 57° C.).

" The real value of the new method consists in dispensing
with this distillation. The object of this operation is the
removal of the black colour, or rather of the black-coloured
matters, by superheated steam. These black matters are
the partially carbonized albumen cells, which swim about in
the fatty acids, because the specific gravity of the two
bodies is about the same. The difficulty is overcome by
oxidizing the mass, by which the specific gravity of the
cells is raised from 0.9 to 1.3. They are thus precipitated,
and the fatty matters can be washed off. The subse-
quent cold- and hot-pressing are the same as with ordinary
methods."

PREPARATION OF THE FATTY ACIDS. 251

Dr. BOCK'S process, according to CARPENTER, consists of
five stages : — (i) Acidification, to remove the cellular tissue
of the fat. (2) Decomposition, by acidulated water, into
dark fatty acids and glycerin. (3) Oxidation, to increase
the specific gravity of the dark membranous matters, so
that they may separate from the fatty acids. (4) Repeated
washing with tvater. (5) Pressing, both cold and hot,

FIG. 43.

The following advantages are claimed for this process : —

1. Freedom from danger of explosion, as the steam is
only used in open tanks.

2. Economy, from simplicity of plant and reduction of
labour, the acidification, oxidation, and decomposition being
all conducted, in rapid succession, in the same wooden tank-

252

CANDLES.

3. Superiority of product, the stearic acid being of great
iiardness, and melting at from 136° to 140° F. (58° to 60° C.).

4. Increased product \ the stearic acid amounting to from.
55 to 60 per cent, of the tallow employed.

5. The oleic acid is more suitable than that obtained
t>y any other process for conversion into palmitic acid by
RADISSON'S method, yielding a greater . percentage of pal-
mitic acid.

Separation of Stearic and Oleic Acids.* — In the or-
dinary method of separation from the mixture of fatty acids
which is obtained by saponification of tallow or palm oil by
means of lime, the solid stearic acid (so-called " stearin ")
is removed by passing through a filter-press at the common,
temperature. Under these conditions a considerable quantity
of the stearic acid remains dissolved in the liquid oleic acid.
By moderate cooling a further quantity of stearic acid can.
be obtained without solidification of the oleic acid. For this
purpose a revolving drum, A, is employed (Fig. 43, p. 251),
containing cold water, supplied by a cooling machine through
the tube (7, and carried off by another tube. The drum dips

into the trough /, contain-
ing the liquid fatty acids,
which are carried round in
a thin layer upon the sur-
face. During the revolu-
tion the oil solidifies, and is
scraped off by the scraper, h,
into the reservoir, F, from
which it is pumped through
a Farinaux filter-press (Figs.
44 and 45). An increased
yield of 4 per cent, on the raw material is obtained, and the

FIG. 44.

' " Dingl. Polyt. J." 263, pp.
372-

J, 49 ; " J. Chem. Ind." 1887, p.

WICKS.

253

oleic acid has a higher value on account of its greater clear-
ness.

Wicks. — The preparation of the wick is a very important
branch of the candle manufacture. The wicks of ordinary
tallow candles are made of the rovings of Turkey skein-
cottoii, lightly twisted, the threads known in the trade as
Nos. 1 6 * to 20 being employed. Twisted wicks are now only
used for tallow f and for wax candles. The plaited or
braided wick was introduced by CAMBAC^RES so as to do
away with the necessity of snuffing. The effect of plaiting
is to cause the wick to bend over during the combustion of

FIG. 45.

I fflfu=—

III

^ -

the candle, so that its end falls outside the flame where it
is exposed to the air, and its complete combustion is thus
insured. This bending over is caused either by twisting the
wick with one strand shorter than the rest, which, being
slightly stretched during the moulding, contracts again and
bends the wick when the fat melts, or by plaiting the
cotton into a flat wick, which naturally takes the required

* That is, 1 6 or 20 Jianks of which weigh I Ib.

f Plaited wicks are unsuitable for tallow candles because, owing-
to the ready fusibility of the fat, the bending over to one side would
cause guttering.

254

CANDLES.

curve. In 1830, DE MILLY found that boracic and phos-
phoric acids obviated snuffing by the formation of a bead at
the end of the wick, which, by its weight, turned the end
out of the flame.

Wicks should be of uniform thickness throughout, and
quite free from knots and loose threads, as the presence of
any of these tends to produce excrescences and guttering.
The finer the thread of which the wick is composed, cceteris
paribus, the more complete will be the combustion of the
fatty materials.

Size of Wicks. — The size of the wick requires to be ad-
justed according to the diameter of the candle and the fusi-
bility of the material (i.e., there must be a sufficient number
of capillary threads to carry up the melted material from the
cup of the candle). If the wick is too large in proportion to
the diameter, no cup can be formed, and guttering ensues ;
if too small, the unmelted substance forming the rim of the
cup does not melt regularly with the descent of the flame,
and forms little pillars round it, which are objectionable,
because they not only cast a shadow, but by-and-by melt,
fall into the reservoir of melted fat, and cause an overflow.

Index to TliicJcness of Wicks*
For Tallow candles— 8 to the lb.— wick (No. 16 yarn) contains 42 threads

45
50
55
60
Steario

63
87
96
108

Pickling. — To prevent too rapid combustion and smoulder-
ing of the wick when extinguished, wicks are dipped in
various pickling solutions, such as boracic acid, i kilo, in

SPON'S "Workshop Keceipts," 1885, p. 355.

WICKS. 255

50 litres of water, or 5 to 8 grams boracic acid to i litre of
water, with the addition of a little sulphuric acid (PAYEN) ;
a solution of sal ammoniac marking 2° or 3° B. (recom-
mended by Dr. BOLLEY), of ammonium phosphate (fre-
quently used in Austria), or of bismuth nitrate (PALMER'S
patent). A solution of 2^- oz. of boracic acid in 10 Ib.
(i gallon) of water, with J oz. of strong alcohol and a few
drops of sulphuric acid, is also said to form a good pickle.

FIELD * treats wicks by steeping in a solution of phos-
phoric acid, or ammonium phosphate, or ammonium phos-
phate and borax, or ammonium phosphate and boracic acid.

The plaited wicks are kept for about three hours in the
pickle, and are then either wrung out, or placed in a centri-
fugal machine, to get rid of the greater portion of the
water. After this they are completely dried in a jacketed
tinned-iron box, heated by steam.

* English patent No. 2061 — 1879.

CHAPTEE III.
MANUFACTURE.

ORDINARY candles are made either by dipping or mould-
ing. Wax candles are made chiefly by basting or
pouring.

Dipping.

The commoner tallow candles are made by this process.

The purified melted tallow is placed in a trough 3 feet
long, made of stout boards, lined with lead, sufficiently deep
for the reception of the largest-sized candles, and furnished,
on the side at which the workman stands, with a wiping
board projecting upwards and outwards along the whole
upper edge of the vessel. On this board the ends of the
candles are, after each immersion, tapped, so that the super-
fluous material may be detached.

Another vessel is generally placed beside this trough, from
which the melted fat is obtainable as required. In it the
tallow is kept properly fluid by means of a steam- or hot-
water jacket.

The operation is thus performed: — 16 or 18 twisted
wicks, according to the weight of candles desired, are looped,
side by side, and as nearly as possible equidistant from each
other, on a wooden, or thin iron, rod (broach, or baguette).
Six or eight rods, or more, carrying the wicks, are then
placed upon a frame, hung above the trough, and capable

MANUFA CTURE.

257

of being raised or lowered at will. There are various dip-
ping machines used by chandlers for this purpose, one of
which, made by Merry weather & Sons, London, is illustrated
by Fig. 46.

The advantage of this arrangement is that a perfectly

FIG. 46.

, Ob .

Dipping- machine.

horizontal position is always secured, even under unequal
pressure at either end, and candles of uniform length are
more easily produced than with the ordinary machines.
• The tallow should be hotter for the first than for the sub-
sequent dippings, because hot tallow penetrates more readily
into the interstices of the wick.

"When the dry wicks have been saturated, they are with-
drawn, care being taken to separate the ends of any thab
may be adhering to each other, and placed on the dripping-
frame, or port, below which is a tray to receive droppings.
' A fresh batch of wicks is then treated in the same way.
For the second and following dippings the fat is at a lower
temperature, about 100° to 110° F., with a tendency ta

258 CANDLES.

solidify at the sides of the vessel. After each immersion
the candles are allowed to cool sufficiently to retain a fresh
coating of tallow at the next dipping. The dippings are-
continued till the candles have acquired the thickness and1
weight desired. Greater care is required for the final dip-
pings to insure symmetry of form ; if the lower ends of the
candles are too thick, they are kept for a little in the molten
tallow, so that the excess may be melted off and the tem-
perature of the bath may be somewhat raised to produce a
more even finish. The lower ends may finally be either cut
away, or removed by placing the candles for a moment on a
copper plate or sheet-iron tray heated by steam, and pro-
vided with a spout to carry away the melted portions.

A different method of dipping is practised at Messrs..
Price's works, Battersea. Instead of dipping the wicks, they
dip a series of steel skewers into the melted candle material,
and, after the candles have been formed and cooled, these
are removed, and the wicks, specially prepared and cut to
the required length, are inserted. This method entirely
prevents the waste of wick by the old method, and the
saving thus effected is said to cover the whole cost of the-
candle-maker's labour.

Moulding.

This operation is performed on the small scale by hand-
frames, and in large works by some of the various moulding
machines.

Hand-frames. — Fig. 47 exhibits the form of the hand-
frames. They are made in all sizes, and suitable for all
materials and shapes. They are convenient for small manu-
facturers, as an assortment of all sizes is less costly than
one moulding machine. They are now, however, compara-
tively little used.

Moulding Machines. — Candle machine?, or continuous

MANUFACTURE.

250,

wick machines, manufactured by Biertumpfel & Son,
Albany Street, London, N.W., and by E. Cowles, Novelty
Works, Hounslow, are shown in Figs. 48, 49, and 52. They
are modifications of the machines introduced into this
country from America about 1849.

FIG. 47.

The following is the method of using these machines : —
i°. Raise the tip moulds to the top of the main moulds.
2°. Insert a very fine wire doubled, and of sufficient
length to go through the tip mould and piston, and extend
below the piston about 6 inches ; insert the end of the wick
in the loop made by the doubled wire, and draw up the
wick through the tip mould, and secure it in any convenient
manner for the first pouring ; then lower the pistons as far
as they will go, pour in the material by means of the jack
(Fig. 51), and when cold shave off the butts with the scoop
(Fig. 50); then place the racks B in a vertical position, with
the tip bars thrown out ; the crank, r, is then turned, and
the candles ejected into the racks ; the racks are then closed
by turning the handle of c, and the tip of each candle is
held precisely over the centre of its mould ; now, the piston-

S 2

2*60

CANDLES.

A is the main body of the stand. B, Movable racks with tip bars.
c, Handle of the eccentric wedge. D, Pistons, having the tip
moulds at the upper ends. E, Spools, with pins on which they
revolve, r, Crank for raising the pistons. G, Handle of cock
for emptying water box. H, Overflow pipe, i, Newly made
candles, j, Clearing pin. K, Pipe for admission of hot or
cold water.

MANUFACTURE.

261

block with pistons is let down, and the wicks are held by
the candles above and the spools below ; passing through

FIG. 49.

Xil!^

the pistons, and through a small aperture in the centre of
the tip mould, they are all strained exactly in the centre of
the moulds, and all is ready for the melted material again,
and, when this is cold, the wicks are severed below the tip

262 CANDLES.

bars, and the racks with the candles are then removed to
any desirable place.

The machine represented by Fig. 46 is for making a

FIG. 50.

Scoop.

large number of small-sized candles, from 24 to 100 to
the Ib. It contains four trays of moulds for 224 candles,

FIG. 51.

Filling can.

and may be arranged to produce at each operation four dis-
tinct sizes — say, 72, 60, 36, and 24 to thelb.

MAN UFA CTURE.

263

A great Improvement in the candle was made in 1861,*
when Mr. J. LYON FIELD patented the conical butt, by which
•a candle can be adapted to any candlestick, without paper

FIG. 52.

or scraping. This invention required special machinery for
^effecting its object, as the tapering butt is larger at the

* FIELD, Cantor Lectures on "Solid and Liquid Illuminating
.Agents," 1883, p. 48.

264

CANDLES.

point of junction with the candle than the diameter of the
latter, and could not, therefore, be extracted from the ordi-
nary mould. Fig. 5 2 exemplifies how this difficulty is over-
come. The moulds for the butts are cast in a separate frame,
which is removed, when the candles are finished, by a chain
and pulley, and the candles are then pushed out of the
stem moulds in the ordinary manner.

Machine for Cutting the Conical Ends of Candles.*
— The conical end may also be made by the cutting machine
shown in Fig. 53.

The plate A, which is capable of being turned round the

FIG. 53-

axle a, is furnished with grooves for
holding the candles. "When the plate
is in an inclined position, the candles
are put in the grooves, in which they
are kept by the guard B, which can
be adjusted to suit the length of the*
candles. On moving A into a vertical
position, the candles slide downwards,
the guard b keeping them from falling
out, and at the same time forcing them
to glide into the conical cutters, c. By
pressing the board C against A, the-
candles are kept in position. The cut-
ters, c, consist of conical bushes, on the
inner wall of which several knives are
fixed; they are attached to the square
rods, h, which loosely move up arid
down in the collars, r. The cutters, c,,
are set in motion by the screw G ; at the
same time the shaft, If, turns, and by the thumb, J, lifts
the bearing, /i, of the square shafts of the cutters, thus

* German patent 19,656, January 10, 1882, Motard & Co., Berlin j.
•' J. Soc. Chem. Ind." 1882, p. 509.

MANUFACTURE. 265,

causing the latter gradually to cut the ends of the candles.
After one turn of the shaft, H, the bearing, jfiT, goes down
again, and restores the cutters to their original position.
At this point the machine stops automatically.

Among the advantages of the moulding machines may be
mentioned the following : — i. Rapidity of the process and
beauty of finish. 2. Candles can be made as well in summer
as in winter. 3. They can be arranged to turn out candles
of different diameters and lengths in one machine. 4. By
simply raising the driving plate, the length of the candles
may be shortened at will.

Moulding Tallow Candles. — The moulds are generally
made of pewter, carefully polished inside. The wick is
inserted, after saturation with melted fat, through the
opening at the smaller end, where it serves as a stopper,
It is fastened at the upper orifice either to the movable top,
or by means of a peg put through the looped end of the
wick, and resting upon the end of the mould, while the wick
is pulled tight from below. The melted fat is poured in,
generally by a small can, orjac/c, Fig. 50, and it is essential
that the tallow should completely fill the mould, which is
of course maintained in an upright position. The candle
must remain entire on cooling, without any cracks, and
should readily be removable from the mould. These results
can only be attained when the fat at the sides cools more
rapidly than that in the interior, and a rapid cooling is
always necessary to prevent contraction of the candle^
Hence, cool weather is the most suitable for the operation.
The proper consistence of the melted tallow to be used is-
known by the appearance of a scum on the surface, which
in hot weather forms between 111° and 119° F. (44° and
48° C.), in mild weather at 108° F. (42° C.), and in cold
weather at about 104° F. (40° C.). If the tallow is too hot
when poured in, the candles are apt to stick, and are difficult

266 CANDLES.

to draw ; if too cold, the candles are not uniform in appear-
ance, but become granular-looking. The candles are ready
to be taken out of the moulds on the day after casting, and
then only require cutting and trimming at the base.

Moulding "Stearin" Candles. — The blocks of the
stearic acid are melted, and, to break the grain or prevent
crystallization, there is added 3 to 5 per cent, of wax, or
10 to 20 per cent, of paraffin, the whole is kept well stirred
till the solidifying point is nearly reached, and then
poured into the moulds, previously heated to about 120° F.
to 125° F. It may be noted as a rule, when fatty acids are
the material to be moulded, that the moulds should be
heated to a temperature about 10° F. under the solidifying
point of the material used, and the fat should be cooled
down as near to its setting point as possible without the
production of any actually solid portions.

By alternately admitting hot and cold water to the
trough, a polished appearance may be communicated to the
candles, but the method of doing this can only be acquired
by actual experience. The fusing point of stearic candles
is 131-132° F., and the produce of various makers in dif-
ferent countries is remarkably uniform in this respect.

Moulding "Sperm" Candles. — The moulding of
sperm candles can be done in almost any of the ordinary
machines. The spermaceti is heated to about the boiling
point of water, run into heated moulds, and, to maintain,
transparency, is cooled as rapidly as possible.

To destroy its highly crystalline structure, spermaceti is
usually mixed with 3 per cent, of wax. Sometimes it is
tinted with gamboge, and denominated transparent ivax.

Sperm candles, when properly made, are remarkable for
the regularity of their flame, a result of the uniformity of
the constitution of the material. Hence the choice of the
sperm candle, burning 120 grains per hour, as the standard

MANUFACTURE. 267

for photometric purposes. On account of their high fusing
point, spermaceti candles are very suitable for use in hot
climates.

Moulding Paraffin Candles. — The same moulds may
be used as for stearic and spermaceti candles. The principal
difference in the operation is as regards the regulation of
the heat. The moulds are heated to about 150.8° F. (66° C.),
or a little above the melting point of the paraffin, and, when
nlled, they are left at rest for a few moments, and then
•suddenly cooled by cold water. This is intended to prevent
crystallization, and consequent opaqueness.

The tendency of the paraffin candle to soften and bend
at temperatures below its melting point is met by the addi-
tion of 5 to 15 per cent, of stearic acid.

FIELD and HUMFREY have patented* the following method
of procedure : — The paraffin, having been melted at about
140° F., is run into moulds heated to the same temperature,
or rather higher. After standing for a few minutes to
allow bubbles to escape, the moulds are surrounded by cold
water. This sudden cooling of the paraffin prevents the
formation of crystals, and candles nearly transparent, and
which draw freely, are thus obtained.

For paraffins of good quality, a wick of ordinary plaited
cotton can be used, and, by dipping it in a weak solution of
boracic acid, the ash of the wick will be fluxed, and the
candles will burn with a bright and clear end.

Moulding Composite Candles. — J. P. WILSON patented
the composite candle in 1840. The material was a mixture
of coco-stearin and stearic acid. This candle is somewhat
greasy, but is comparatively cheap, and gives a good light.

Another method is to melt together, over a water bath,
100 parts of stearic acid and 10 to n parts of bleached

* Patent No. 454, February 22, 1856.

268 CANDLES.

bees'-wax, but, to insure success, the mixture must remain
over the bath from twenty to thirty minutes without being
stirred. At the end of that time the fire is extinguished,
and the mixture allowed to cool until a slight pellicle i&
formed on the surface, when it is cast direct into the moulds,
previously heated to about the same temperature.*

Cutting and Polishing. — The candles taken from the
moulds have the ends cut by a circular saw, and have the
length adjusted. The machinery allows them afterwards-
to fall upon an endless woollen cloth belt, supported by
rollers, which carries them under other similarly covered
cylinders, revolving in the opposite direction, by which
means they receive a polish. Some of the higher class
candles are hand-polished by rubbing with a woollen cloth
moistened with aminoniated alcohol.

Night-lights. — These have taken the place generally of
the old rushlight. Formerly they were called mortars.^
As intensity of light is not required, a very thin wick is
used, with a disproportionate thickness of fatty matter, so
that a very deep and full reservoir is formed, containing an
excess of melted fat, which is prevented from flowing over
by the case of cardboard or wood shaving, or by a small
glass vessel.

They were first made of wax or spermaceti, or a mixture
of wax and spermaceti, but now generally from stearin, and
coco-stearin, or from cocoa-nut oil and palmitic acid, in
varying proportions.

The wick is fastened to a little square of tin-foil — the
sustainer — and secured in the centre of the little case by
a drop of wax. The cases, placed in rows, are filled by
pouring the melted material into each from a jack.

* SPON'S "Workshop Keceipts," 1875, p. 358.

f More (Lat.), death — from their use in death-chambers.

MANUFACTURE. 269

In another kind of night-light made of harder material,
largely consisting of palmitic acid, the case is dispensed with,
and, during the burning, the light is placed in a small glass.
This description is made by running the melted fat into a
special moulding frame. When cold, the night-lights are
turned out ready punctured for the wick, which is after-
wards inserted by hand.

Wax Candles.

The wicks for wax candles are made of twisted unbleached
Turkey cotton. Plaited wicks are not so suitable, as the
plaiting, by retarding the capillary action, necessitates the
employment of a larger wick, which is apt to curl round in
the name and obscure the light.

Wax is not well adapted for moulding, on account of
its tendency to adhere to the mould, and its great contrac-
tion on cooling.

The process of making wax candles is analogous to that
of dipping, but, instead of dipping the wicks into the
material, the melted wax is poured upon the wicks.

The wicks, having been warmed in a stove, are suspended
on a hoop of wood or metal, which hangs over the cauldron
of melted wax. The operator causes the hoop to revolve,
and, taking a ladleful of the fluid material, pours it over each
wick in succession, taking the precaution to keep turning
the wick quickly on its axis by the fingers at the same time,
so that the wax may not accumulate more on one side of
the wick than the other. After three or four revolutions
of the hoop, or when the candles are coated to about one-
third of their proper size, the first hoop is laid aside, and,
while its load is cooling, another hoop is taken in hand.
The candles on the first hoop are afterwards again basted
till they are half the required size. They are next, while
still warm, rolled, upon a marble slab sprinkled with water,

270

CANDLES.

with a rolling board, so as to make the cylinders smooth
and of a uniform thickness. After this they are suspended
again on the hoop, but in a reversed position, and the
basting is continued till they are of the required size. When
this is attained they are once more rolled on the slab, cut to-
a certain length, and have their tops trimmed with a piece
of wood. The operation throughout is one requiring much
skill and experience. A section of a well-made wax candle
shows rings, resembling the annular layers of a tree, and
corresponding to the number of bastings.

Large Wax Candles for ecclesiastical use are made by
placing the wick on a layer of wax, bending the wax over
it, and then rolling, as in the ordinary wax candles. Other
layers of wax may, if necessary, be rolled on up to the re-
quired thickness.

Wax Tapers. — The materials— wax, with stearic acid,
paraffin, &c. — are melted in a jacketed pan (Fig. 54) ; and

FIG. 54.

Silver-plated bougie or draw-wick pan, with winding drum,
to heat by steam.

the wick, usually of several fine yarns of cotton, twisted to
suit the thickness of the taper to be made, is wound on a
drum, and drawn through the pan.

CHAPTER IY.
SPECIALITIES.

Belmont Sperm Candles. — The body of this description
of candle is said to be a mixture of stearic and cocinic acids,
with a portion of paraffin.

Belmont Wax Candles consist of stearic acid with a
small proportion of wax. They are tinted with gamboge.

Ozokerit Candles. — These are a speciality of Field, of
Lambeth. They have a remarkably high melting point
and great illuminating power. They burn with a dry cup,,
are not liable to gutter, are free from smell, and not greasy
to the touch. They do not bend or soften in a warm atmo-
sphere like ordinary paraffin candles. The hardness and
liigh melting give rise to one drawback — the wick is apt to
smoulder on extinction. The cause of this is the fact that
the cup of the candle dries and solidifies as soon as the flame
is blown out, so that there is no liquid matter left to ex-
tinguish the spark. This difficulty, however, is overcome
by special attention to the preparation of the wick.

Double- and Treble-wick Candles of large diameter
are made for police and nautical use.

Hydraulic-pressed Candles. — E. L. BROWN, of Chicago,
has patented* a process to prevent unnecessary waste in

* United States patent No. 345,272, July 13, 1886.

272 CANDLES.

the use of candles, by so treating them in the process of
manufacture that they will melt very slowly. This is ac-
complished by forming the body of the candle under extreme
pressure. The candle cylinder is first moulded in the usual
way, and is then compressed by means of a hydraulic press.
Hygienic Candles. — WATSON and FULTON* prepare
these by incorporating iodine and a small quantity of
sulphur with the candle material, and they consider that
during the combustion the iodine and sulphur are both eli-
minated in the free state, according to the equation —
4HI + S02 = I4 + S + 2H20.

Wright's Pulmonic Candles. — These are impregnated
with anti-asthmatic remedies, and are made on Messrs.
FIELD'S patent for securing perfect combustion and freedom
from guttering by means of three or more air channels
-running parallel to the wick throughout the length of the
candle.

SWEETSER, BELL, and BOHM have taken out a patent f for
moulding and pressing candles direct from the candle
material, whilst in a solid or plastic state, in continuous
lengths. The material is kept under pressure, and, being
forced through a tube, carries the wick along with it in situ.
The coated wick has then only to be pointed, by being pro-
jected against a rotary cutter, or by other means, and cut
into lengths to form candles.

Ornamental Candles.

Decorated Candles. — The materials for candles intended
to be decorated should be of the best quality, and should
have a high melting point. They may be varnished by gum

* English patent No. 10,876—1885.
t „ „ No. 13,417—1885.

SPECIALITIES. 273

dammar, dissolved in turpentine or alcohol, or by mastic
varnish, and the design painted on by hand or otherwise.

Cable, Twisted, or Spiral Candles. — These are moulded
in the ordinary way, and then turned by means of a special
lathe ; or they may be cast in rifled moulds, from which, on
cooling, they are wound out.

Coloured Candles. — Among the colouring matters used
for candles are the following : —

Blue : Prussian blue, indigo, ultramarine, copper sul-
phate, aniline blue.

Red : Carmine, Brazil wood, alkanet root, minium, ver-
milion, aniline reds.

Yellow : Gamboge, chrome yellow, naphthaline yellow.
Green : Mixture of blue and yellow colours.
Purple or Violet : Mixture of blue and red colours.
Neutral Tints : Oxides of iron, yellow ochre, Frankfort

black.

Black : Fruit of Anacardium occidentale, aniline blacks,
In order to dye paraffin candles with an aniline base,
such as magenta, the dye is first dissolved in stearin, and a
little of the resulting stearate is added to the paraffin.

There are two ways in which candles may be coloured
black :*—

(1) Anacardium Method. — Paraffin, or whatever material
is desired for the candles, is heated to from 200° to 210° C.
with 25 percent, of its weight of the chopped/ ruit of Anar-
cardium occidentale. Candles prepared in this way are
equally black throughout, and yield no irritating vapours
when burnt.

(2) Aniline Method. — The material to be dyed is heated
a few degrees above its melting point with i to 2 per cent.
of nigrosine fat colour (prepared by Destree, Wiescher, &

* " Chemist and Druggist," 1884, p. 290.

274 CANDLES.

Co., of Brussels). Paraffin and spermaceti require i per
cent. ; stearin and wax require from i \ to 2 per cent. The
candles thus prepared are said to be of a sombre hue
throughout, and of a jet-black appearance.

Quality of Candles.

In judging of the quality of candles, the following points
should be considered :* —

(i) Nature of the fatty materials. (2) Whiteness.
(3) Transparency. (4) Hardness. (5) Dryness to the touch.
(6) Fusing point. (7) Form and moulding, (8) Character
of wick. (9) Nature of the flame — is it uniform, long or
short, well supplied, brilliant, without smoke ? (10) Does
the cup burn dry, or is it filled with melted fat? (n) Is
the fatty matter free from mineral ingredients ?

Bending Point. — Candles may be compared, as to their
tendency to bend in warm atmospheres, by observing their
behaviour when kept, for an hour or more, in a cupboard,
•or oven, heated to 100° F.

Illuminating Value. — The illuminating value of candles
may be determined by the photometer, as described in the
fourth volume of this series of Handbooks, pp. 310-315.

* CRISTIANI, "Treatise on Soap and Candles," p. 488.

CHAPTER Y.
BYE-PRODUCTS.

Oleic Acid. — The oleic acid may be used for soap-making,
and is specially valuable for the production of soap for the
use of textile manufacturers.

Oleic acid from the linie process is the best for this
purpose, because it is free from hydrocarbons. If a soap is
made from oleic acid containing hydrocarbons, when dis-
solved in water these separate and adhere to the fabric.
Oleic acid free from hydrocarbons, when saponified by heat-
ing in a test-tube with twice its bulk of alcoholic soda,
forms a soap which gives a dear solution when dissolved
in water.

It may be also converted into palmitic acid by PtADissoN's
method, which is founded on the discovery of VARENTRAPP,
in 1841, that when oleic acid is heated with a great excess
of caustic potash it is decomposed into palmitic and acetic
acids, and hydrogen, according to the equation —

C18H3402 + 2KHO = C16H31K02 + C2H3K02 + H,

Oleic acid Potash Potassium Potassium Hydro-

palmitate acetate gen.

The following is an outline of the method followed by
RADISSON,* and described by CARPENTER :t—

* English patent 1782 — 1869.

•j- SPON'S "Encyclopaedia," pp. 584-586; "Journ. Soc. Chem-
Ind." 1883, p. 98.

T 2

276 CANDLES.

About i \ ton of oleic acid and 2j tons of caustic potash
lye (43° B.) are pumped into a cylindrical cast-iron vessel,
about 12 feet in diameter and 5 feet high, provided with a
sheet-iron cover. The vessel is heated from below by a fire,,
sufficiently far off to avoid burning. The steam evolved
passes off by a large man-hole on the top. This is closed
when the soap gets dry, and the gases afterwards disengaged
are conveyed through pipes, first to a condensing tower, and
thence to a gas-holder. The materials are kept constantly
stirred by a mechanical agitator, in order that the heat may
be equally distributed, and that the froth, which rises
abundantly, may be beaten down. Eventually, the soap
becomes fused, and at 554° F. begins to give off hydrogen.
The temperature is slowly raised to 608° F., and the gases
then given off have a characteristic odour. If the heat were
longer continued the materials would enter on the stage of
destructive distillation. The operation at this stage is there-
fore suddenly stopped by the introduction of steam and
water through a G-IFFARD injector, and, at the same time, a.
door in the bottom of the cylinder is opened, through which
potassium palmitate falls into an open tank. Here the soap,
with a sufficient quantity of water, is melted by means of a
jet of steam. After subsidence the contents of the tank
become separated into two layers, the upper of neutral
potassium palmitate, and the lower of potash lye (usually
about 1 8° B.). The palmitate is removed to another vessel,.
decomposed by sulphuric acid, and the liberated palmitic
acid is washed with water to free it from potassium
sulphate.

The palmitic acid thus obtained is of a clear chocolate
colour, and crystallizes in large tables. Its melting or
solidification point ranges from 122° to 127° F., according
to the character of the oleic acid employed. Distilled in the
usual apparatus, it leaves only 3 per cent, of pitch. After

BYE-PRODUCTS. 277

-distillation, it is very white, and jburns with a clear smoke-
less flame. Moulded into candles, it compares very favour-
ably with the best stearic acid, and, when mixed with
ordinary stearic acid, breaks the grain of the latter, and
gives it a semi-transparency very valuable in the eyes of
the candle-manufacturer.

RADISSON has experimented with the object of replacing
potash by soda, but experienced at first a difficulty in heat-
ing the materials uniformly. This difficulty he successfully
overcame by introducing paraffin. When paraffin is present
with sodium oleate and excess of soda, the mass becomes
fluid on heating, and a uniform temperature throughout is
speedily established. There is no fear of decomposing the
sodium palmitate, since the point at which this would occur
is above the temperature at which paraffin distils. The
small quantities of paraffin which are unavoidably volatilized
are caught in a condenser, and the hydrogen evolved is so
charged with hydrocarbons as to form a good illuminant.

At the end • of the reaction the whole is allowed to fall
into water, as in the former process, and after a time three
layers are formed — the bottom layer of soda lye and sodium
acetate, the middle of neutral sodium palmitate, and the
uppermost of paraffin. The top and bottom layers are re-
moved, and serve for succeeding operations, and the sodium
palmitate is decomposed by sulphuric acid. The palmitic
acid obtained has, according to the author of the process, a
solidifying point varying from 140° to 154° F., according to
the kind of oleic acid operated upon.

A ton of palmitic acid by the first process costs about
^13, by the second only about ^7 105.

The candle-maker gains, according to the inventor, the
following advantages by adopting this process : — (i) Utiliza-
tion of the olein, a troublesome bye-product of variable value.
(2) The floating capital necessary for the purchase of raw

278 CANDLES.

material is diminished by about 30 per cent., the proportion
of hard candle material being increased by nearly the amount
of olein produced. (3) Low-priced grease, whose value
varies in inverse proportion to its richness in olein, can be
employed. (4) The candle material produced is little, if at
all, inferior to that produced by any other method.

Glycerin, C3H5(OH)3 — Syn. GLYCEEOL — the base of the
ordinary fats, is a colourless, odourless, syrupy liquid of
intensely sweet taste, and miscible in all proportions with
water. It was discovered in 1779 by SCHEELE,W!IO obtained
it, in the preparation of lead-plaster, by saponifying lard with
lead oxide. CHEVEEUL afterwards showed that it is a con-
stant product of the saponification of the ordinary fats. It
is not susceptible of the alcoholic fermentation, but an
aqueous solution of glycerin, if kept in a warm place, is
slowly converted by the action of brewers' yeast into pro-
pionic acid (C3H602). It has no action on vegetable colours.
When heated in air at the ordinary pressure, it decomposes
— one of the products being acrolein (C3H-40), which has
a well-known peculiarly irritating odour : —

C3H5(OH)3 = 2H20 + C3H40

Glycerin Water Acrolein.

In presence of aqueous vapour under pressure in air
and in vacuo, it can be distilled unchanged. Its specific
gravity is 1.27—1.28. It boils in vacuo at 179.5° ^-> anc^ a^
755-55 mm- pressure at 200.08° C. According to F.
NITZSCHE,* a method of obtaining glycerin in crystals was
discovered by KRAUT in 1870. This method is applied in
the works of Sarg & Co. at Liesing, near Vienna, to the
production of glycerin, the crystals being freed from

* " DingL Polyt. J." ccix. 145 ; WATTS' " Dictionary of Chem."
vol. viii. pt. ii. suppt. 3, p. 871.

B YE-PROD UCTS. 279

adhering mother liquor in a centrifugal machine, then dried,
and melted.

When quite pure and anhydrous, it crystallizes* on ex-
posure to a very low temperature, especially if agitated.
The crystals so obtained are mono-clinic, perfectly colour-
less, and melt at 60° F.

According to WERNER, f commercial glycerin may be
made to crystallize by passing a few bubbles of chlorine
into it. f

Glycerin does not, for the most part, exist in the free
state, or ready formed, in natural fats, but, when the fat
is saponified, glycerin is formed by the addition of the
elements of water to the radical glyceryl (see p. 52). The
reaction is similar to that by which common alcohol may be
produced from ethyl acetate (acetic ether) : —

CH3CO.OC2H5 + KHO = CH3CO.OK + C2H5.HO

Ethyl acetate Caustic Potassium Alcohol,

potash acetate

In fact, glycerin is an alcohol, bearing the same relation
to the fats stearin, palmitin, olein, &c., that ordinary
alcohol bears to the compound ethers.

BERTHELOT'S researches on the synthesis of fats, by the
direct action of acids on glycerin, have shown that glycerin
is a tri-atomic alcohol, in which one, two, or three atoms of
hydrogen may be replaced by acid radicals, producing fatty
or oily compounds, some of which are identical in com-
position and properties with the natural fats.J

The following table shows the specific gravities and
freezing points of aqueous solutions containing different
percentages by weight of glycerin : —

* Eoos, " Journ. Chem. Soc." 1876, i. 651.

f "Zeitschr. f. Chem." [2], iv. 413.

% See also " Oils and Varnishes," p. n.

280

CANDLES.

Percentage.

Specific Gravity.

Freezing Point (C.).

.024

_ j0

.051

- 2.5°

•075

- 6°

.105

-I7.50

5°

.127

-3I.340

•159

70
So

.179
.I2O

Below

.232

'-35°

.241

Some of the chief methods proposed for the recovery of
glycerin from soap lyes have been given in Part I. p. 175.

The glycerin separated in the various processes for the
preparation of fatty acids to be used in the manufacture of
candles is now of great commercial importance. The crude
or raw glycerin is obtained by concentrating the sweet
water by evaporation to about 44° Tw. (sp. gr. 1.22).
Some candle-makers carry the operation no farther, but
dispose of the raw article to those who make its purification
a branch of their business.

The purification may be effected by superheated steam in
the manner already described (pp. 247 and 248).

Removal of Glycerin from Fats before Saponification. — A
patent has been taken out in the name of IMRAY * with this
object. The fatty matter is mixed with about one-third of
its weight of water, and from \ to ij per cent, of its
weight of zinc oxide. It is then subjected in a close vessel
to the action of steam at a pressure of from 100 to 130 Ib.
per square inch from three to four hours. The product thus
saponified is treated as in calcareous saponification, but the
very small proportion of mineral substance used enables the
acid treatment for decomposition of the soap to be dispensed
with, and the acid fat can be at once employed in the manu-
facture of soap or candles.

* English patent 5112, October 27, 1882.

B YE-PROD UCTS. 28 r

Testing Glycerin.* — Oxide of lead, lime, and butyric
acid, the result of incomplete purification, are the impurities
most frequently met with in commercial glycerin.

Lime and lead are indicated when, on the addition of a
few drops of dilute sulphuric acid to a portion of the sample
diluted with its own volume of water and with a little
alcohol, a white precipitate is obtained. If the precipitate
is blackened by sulphuretted hydrogen, lead is present.

Butyric acid is detected by mixing strong alcohol and
sulphuric acid with the sample, and heating slightly, when,
if this impurity be present, the agreeable odour of butyric
ether becomes manifest.

Formic acid, if present, gives the odour of formic ethyl
(peach-flower smell) when the glycerin is heated with alcohol
of 40° and a drop of sulphuric acid.

Oxalic acid would be shown by a white precipitate on
the addition to equal quantities of glycerin and water of
2 drops of a solution of calcium chloride containing a little
ammonia (free from carbonate).

Glucose would reduce FEELING'S copper solution ; and cane
sugar, after inversion by a mineral acid, would be detected
by the same reagent. Or, the presence of either would be
detected by the polariscope, as glycerin itself has no optical
activity.

The chloroform test consists in mixing equal parts of
chloroform and glycerin, stirring, and then leaving the
mixture to settle. Of the two layers which form, the upper
one consists of pure glycerin, the lower of chloroform with
the impurities. If the glycerin is pure, the chloroform re-
mains clear ; if not, a greyish belt is observed at the line of
separation.

Perfumers test glycerin with silver nitrate ; if pure, there

* F. JEAN, " Journ. de Pharm. d' Alsace-Lorraine," ix, 136; "Year
Book of Pharmacy," 1883, p. 258.

282 CANDLES.

is no sensible coloration produced at the end of twenty-four
hours.

Sulman and Berry on the Examination of Com-
mercial Glycerin.* — Colour. — SULMAN and BERRY state
that the colour of commercial glycerin does not necessarily
indicate whether a sample is crude or once distilled, for,,
although crude samples are usually highly coloured, pale
samples are often obtained by the lime process, while once
distilled samples from soap lyes are sometimes very dark.

Mineral Matter. — On incineration, distilled glycerin never
yields more than 0.2 per cent, of mineral matter. Crude
glycerin from soap lyes gives from 6 to 14 per cent, of ash.
The crude product obtained in candle factories, either by
the lime, magnesia, zinc, or other processes, contains a
smaller proportion of mineral matter than that from soap
lyes.

" Crude glycerin invariably contains albuminous matters,
derived from the nitrogenous envelope of the fat globules,
often to the extent of several per cent. Here, as usual, it
is the soap lyes which yield the most heavily contaminated
samples owing to the ready solvency of the proteid matters
contained in the fats by the alkalies employed. They
are chiefly objectionable on account of the mechanical
difficulties to which they give rise in the subsequent distil-
lation, and on account of the contamination of the distillate
with empyreumatic and coloured products. In glycerin
from soap lyes a frequent and very objectionable impurity
is rosin, which often imparts a characteristic fluorescence to
the distillate. Rosin oils may be detected in the distilled
samples by shaking with ether, the bulk of which rises to
the surface on standing, and contains most of the oil pre-
sent, which may be recognized on evaporation of the de-

* " Analyst," 1886, p. 12.

BYE-PRODUCTS. 283.

canted ether by its physical character, its odour on warming,
and its characteristic taste. Glycerin from candle factories
contains no rosin.

" On acidifying crude glycerin from soap lyes, a milky
white precipitate is frequently obtained, the quantity of
which depends upon the process of extraction adopted, and
whether acidification has previously taken place. The pre-
cipitate consists mainly of resinous acids and free sulphur
(the latter being due to the decomposition of the sulphur
compounds introduced with the caustic soda used for the
saponification of the fats) ; the sulphur has been found at
times to constitute 40 to 60 per cent, of the whole precipitate.
The sulphur is hardly less objectionable than the rosin, as
it gives rise to volatile sulphur compounds on distillation.

" The albuminous matters cannot be completely removed
from the crude glycerin except by distillation, and for ana-
lytical purposes it is not necessary to separate them from
the other organic impurities, which are separable by basic
acetate of lead, and of which they form the bulk.

" Crude glycerin obtained by the sulphuric acid pro-
cesses of fat saponification is always charged with sul-
phates, and generally sulphites; occasionally appreciable
quantities of sulphide are found. Both the latter are
injurious in distillation. Glycerin from candle factories
frequently contains some free fatty acid, which is usually
oleic.

" With regard to the impurities in distilled glycerin the
traces of mineral matter present may consist of sodic chloride
and salts of lime, copper, and iron, the two latter being
derived from the still and fittings, the presence of the
copper being due to formic acid. This acid is produced
either by the action of traces of mineral acids upon the
glycerin in the still (oxalic acid being first formed and
again immediately decomposed with liberation of carbonic

284 CANDLES.

acid and the volatile fatty acid), or as one of the final pro-
ducts of the action of the small quantity of alkali remaining
in the crude glycerin upon the albuminous impurities. The
chief organic impurities of first distillates from soap lyes
are formic, butyric, and oleic acids, rosin oils, colouring and
empyreumatic products, and occasionally organic sulphuric
compounds. In the samples from candle factories butyric
acid sometimes (according to PERUTZ) reaches the amount
of 0.5 per cent. The glycerin obtained by the WILSON-
PAYNE process generally contained considerable amounts of
the higher fatty acids.

" For the determination of the total mineral matter pre-
•sent in a sample, two separate ignitions are requisite, as it
is impossible to burn off all the carbonaceous portion of the
residue without volatilizing some of the salt which is almost
invariably present. The first portion taken is warmed, the
vapours ignited, &c., and the charred mass so obtained is
•exhausted with hot water. The solution is filtered, and the
chlorides determined by titration with standard silver solu-
tion. A second portion is burnt in the same way, and the
residue strongly ignited, using the blowpipe, if necessary,
till no more carbon remains, and the ash is fairly white ; the
weight is taken, the residue dissolved, and the chlorides
determined in it. The difference between the two deter-
minations gives the amount of chloride volatilized, which
is calculated as sodic chloride and added to the weight of
the second ash.

" Chlorides cannot be directly determined in glycerin by
precipitation or titration with silver, owing to the solu-
bility of argentic chloride in this liquid, and to the reduc-
tion of the nitrate in the cold by the contained impurities.
They are therefore determined in the ash, as before directed.
Crude soap lye glycerin usually contains from 5 to 10 per
cent, of salt.

BYE-PRODUCTS. 285

"Alkalinity, due almost entirely to sodic carbonate, is
most readily estimated by titration of the diluted sample
with standard acid. Litmus is the best indicator, phenol-
phthalein and methyl orange giving indistinct end reac-
tions. Crude soap glycerins are usually alkaline, and pur-
posely so, owing to the risk of concentrating them in pre-
sence of acid. We have found them to contain, as a rule,
from 0.5 to 2 per cent., the amount present depending
to some extent upon the process adopted in their prepara-
tion. In a case, cited by Dr. FLEMING,* where the soap had
been separated from the lyes by excess of alkali instead of
salt, the resulting glycerin contained 31 per cent, of sodic
carbonate.

" Calcium, Zinc, Iron, Magnesia are determined as usual
in the ash.

" CAP'S test for lime in the original glycerin consists in
the addition to the sample of an equal volume of alcohol
containing i per cent, of sulphuric acid, the alcohol largely
diminishing the solubility of the calcic sulphate : we have
found, however, that the ordinary ammonium oxalate test
gives quite as delicate results.

" Organic Impurities, consisting of albuminous and resin-
ous compounds, colouring matters, and the higher fatty
acids, are largely precipitable by basic lead acetate, and may
be estimated with considerable accuracy by a modification
of CHAMPION and PELLET'S process. The glycerin is suffi-
ciently diluted with water, carefully neutralized with acetic
acid, and warmed to expel carbonic acid : when cool, the
basic acetate is added in slight but distinct excess in the
cold, and the mixture well agitated. The precipitate is
collected upon a tared, or, better, a double counterpoised
filter, well washed (the first washings may be effected by

* " Seifenfabrikant," i. no.

286 CANDLES.

decantation in the beaker), dried at 100° C. to 105° C., and
weighed. The precipitate and filter papers are ignited
separately, each with a few drops of nitric acid. The weight
of the lead oxide (and perhaps sulphate) obtained, when
deducted from the weight of the dried precipitate, gives the
organic matter contained by the latter. The nitric acid
prevents the reduction of the plumbic sulphate, when
present, to sulphide or metallic lead ; to control the result,
and with the above view, the precipitate, instead of being
ignited, may be treated with hot nitric acid, diluted, and
filtered, the lead being determined in the filtrate by any
convenient method. In this way any sulphate of lead
present in the precipitate is left undissolved. It has been
recommended to ignite the precipitate obtained by the basic
acetate of lead, with sulphuric acid, to multiply the weight
of the sulphate obtained by 0.736, and to deduct the weight
of lead oxide obtained as before directed ; but this method
is obviously inaccurate, as it takes no account of the sul-
phates almost invariably present, to some extent, in crude
glycerin, and thus includes the sulphuric acid in terms of
4 organic impurity.' No average figures can be given as
to the varying amounts of the above impurities for crude
glycerin, but in distilled samples the amount present should
not exceed 0.5 to i per cent.

" Fatty Acids are often present in such proportions that
mere dilution with water causes their precipitation ; smaller
quantities may be detected by diluting and applying the
elaidin test — the flocculent yellowish precipitate of elaidic
acid obtained by passing peroxide of nitrogen through the
solution being1 less soluble in glycerin than the original
oleic acid.

" The Nitrate of Silver Test, used by perfumers, depends
upon the production of a black precipitate of metallic silver
on standing for some time. This reduction is principally

BYE-PRODUCTS. 287

due to the presence of small quantities of acrolein and of
formic acid ; a good distilled glycerin should give no pre-
cipitate after twenty-four hours, though nearly all com-
mercial samples we have met with in bulk do speedily effect
reduction.

" For the detection and estimation of Sugar, FEELING'S
method is readily applicable. This substance cannot occur
except as an adulteration, and hence it is only necessary to
look for it in distilled samples. The same remark of
course applies to glucose. Sucrose and dextrin, it need
hardly be said, require the usual inversion by heating with
dilute (5 per cent.) sulphuric acid before applying the
FEHLING solution. The small amounts of other impurities
present do not interfere with this test. That it is constantly
necessary to examine samples for sugar is shown by the
fact that a spurious glycerin has been found by a conti-
nental chemist to be composed of a saturated solution of
glucose and magnesium sulphate.

" For Sugar (also glucose and dextrin, but not lactose
or ardbin, which give no reaction) MASON'S test has been
found fairly delicate and reliable, using 0.5 c.c. of the sus-
pected glycerin, 15 c.c. distilled water, 2 drops of strong
nitric acid, and 0.5 gram of amrnonic molybdate. On
boiling for two or three minutes, or longer, if the quantity
present be small, a blue colour is produced by the above
substances; 0.25 per cent, may be readily detected. The
chief points to be observed are — that the liquid must not
be too highly coloured, and the acid must not be in excess
of the quantity mentioned.

" ZSIGMONDY and BENEDIKT* have recently put forward a
process for the estimation of glycerin, depending upon its
oxidation by alkaline permanganate solution into oxalic

* " Analyst," November 1885, p. 205.

288 CANDLES.

acid ; the latter is precipitated by adding calcic acetate, and
may be determined by titration with standard potassic per-
manganate in an acid solution. Fatty acids have been
found not to interfere with this reaction."

For the manufacture of dynamite, which forms the
great outlet at present for the large quantities of glycerin
obtained from the soap and candle industries, distilled
glycerin is alone of use ; and it must further answer the
following conditions before it can be accepted as sufficiently
pure for nitration : —

(1) Entire freedom from salt, iron, lead, lime, and fatty
acids.

(2) Complete absence of sugar (which can be present only
as an adulteration).

(3) The sample must be of good colour and practically
odourless.

(4) Specific gravity must at least reach 1.26.

Olein. — The olein obtained in the preparation of stearin
(p. 231),* and known technically as oleo, is now largely
employed in the manufacture of margarine.

* For further details see " Oils and Varnishes," p. 18 ; and Cantor
Lectures on "Milk Supply, Butter, and Cheese-making," by E.
BANNISTER (April 1888).

APPENDIX.

Composition of Black Ash.

CfI»-VTT

BROWN

UKOEB.

oTOH*

and

HANK.

CYNASTOIT

Sodium sulphate ....

1.99

i-54

0-395

„ chloride ....

2-54

1.42

2.528

,, carbonate ....

23-57

44.41

36.879

„ silicate .....

—

1.182

,, aluminate ....

—

0.689

Soda — caustic, hydrated .

II. 12

Calcium carbonate ....
„ sulphide ....

12.90
27.61

3.20
30.96

3-3I5
28.681

„ sulphite ....

—

2.178

Lime

7-15

8^35

9.270

Magnesia

O.IO

0.254

Magnesium silicate ....

4-74

Alumina

—

0.79

I.I32

Water

2.IO

—

0.219

Ferric oxide

—

i-75

2.658

Ferrous sulphide ....

2-45

0-371

Silica

0.89

Sand . . . . .

2.02

2.20

0.901

Charcoal

i-59

5-32

7.007

Ultramarine .....

0-959

Total ..'....

99.78

100.93

98.180

APPENDIX.

Strength of Solutions of Caustic Potash at 15° C. (59° F.)
(TUNNERMANN).

Density.

K20 in
ioo Parts.

Density.

K2Oin

ioo Parts.

•3300

28.290

I.I437

14.145

•S^r

27.158

1.1308

13.013

.2966

26.027

I.U82

11.882

.2805

24.895

1.1059

10.750

.2648

23.764

1.0938

9.619

•2493

22.632

1.0819

8.487

.2342

21.500

1.0703

7-355

.2268

20.935

1.0589

6.224

.2122

19.803

1.0478

5.002

.1979

18.671

1.0369

3.961

.1839

17.540

1 .0260

2.829

.1702

16.408

I.OI53

1.697

.1568

15.277

1.0050

0.566

Density of Caustic-potash Solutions (SCIIIFF).

Density.

KHOin
ioo Parts.

Density.

KHO in
ioo Parts.

.036

.411

.077

•475

.124

•539

•175

.604

.230

.667

.288

.729

•349

.790

APPENDIX.

291

Strength of Solutions oj Caustic Soda at 15° 0. (59° F.)

(TtJNNERMANN).

Density.

Na2O in
ioo Parts.

Density.

NasO in
ioo Parts.

1.4285

30.220

1.2392

15.110

I-4I93

29.616

1.2280

14.506

1.4101
1.4011

29.011

28.407

1.2178
1.2058

13.901
13297

1.3923

27.802

1.1948

12.692

1.3836

27.200

1.1841

I2.o88

I-375I

26.594

LI734

11.484

1.3668

25.989

1.1630

10.879

1-3586

25.385

1.1528

10.275

I-3505

24.780

1.1428

9.670

1.3426

24.176

I.I330

9.066

1-3349

23-572

1-1233

8.462

I-3273

22.967

I."37

7.857

1-3198

22.363

1.1042

7-253

I-3I43

21.894

1.0948

6.648

1-3125

21.758

1.0855

6.044

I-3053
1.2982

21.154
20.550

1.0764
1.0675

5-440
4.835

1.2912
1-2843

19-945
19-341

1.0587
1.0500

4.231
3.626

1-2775
1.2708

18.730
18.132

1.0414
1.0330

3.022
2.418

1.2642

17.528

1.0246

1.813

1.2578

16.923

1.0163

1.209

I-25IS

16.319

1.0081

0.604

1.2453

I5-7I4

U 2

292

APPENDIX.

Soda Ash : Table of Percentages of Soda and Sodium Car-
bonate corresponding to "English" and DECROIZILLBS'
Degrees.

Percentage of

•Degrees.

Percentage of

Degrees.

Soda.

Sodium
Carbonate

English

DECEOI-

ZILLES*.

Soda

Sodium
Carbonate

English

DECEOI-

ZILLKS'.

30.0

51.29

30.39

4742

49.0

83.78

49.64

77-45

30.5

52.14

30.90

48.21

49-5

84.64

50.15

78.24

31.0

53-00

3MI

49-00

50.0

85-48

50.66

79-03

31-5

53-85

3i-9i

49-79

50.5

86.34

51.16

79-82

32.0

54-71

32.42

50.58

51.0

87.19

5L67

80.61

32-5 1 55-56

32-92

51-37

5i-5

88.05

52.18

81.40

33-o

56.42

33-43

52.16

52.0

88.90

52.68

82.19

33-5

57-27

33-94

52.95

52-5

89.76

53-19

82.98

34-0

58-13

34-44

53-74

53-o

90.61

53-70

83.77

34-5

58-98

34-95

54-53

53-5

91.47

54-20

84-56

35-o

59-84

35-46

55-32

54-o

92.32

54.71

85-35

35-5

60.69

35-96

56.11

54-5

93.18

55-22

86.14

36.0

6i-55

36.47

56.90

55-o

94-03

55.72

86.93

36.5

62.40

36.98

57-69

55-5

94.89

56.23

87.72

37-o

63.26

37-48

5848

56.0

95-74

56.74

88.52

37-5

64-11

37-99

59-27

56.5

96.60

57.24

89-31

38.0

64.97

38-50

60.06

57-o

97-45

57-75

90.10

38.5

65.82

39-oo

60.85

57-5

98-31

58.26

90.89

39.0 66-68

39-51

61.64

58.0

99.16

58-76

91.68

39-5

67-53

40.02

62.43

58-5

1 00.02

59-27

92.47

40.0

68.39

40.52

63.22

59-o

100.87

5977

93.26

40-5

69.24

41.03

64.01

59-5

101.73

60.28

94-05

41.0

70.10

41-54

64.81

60.0

102.58

60.79

94.84

41-5

70.95

42.04

65.60

60.5

103.44

61.30

95-63

42.0

71.81

42-55

66.39

61.0

104.30

61.80

96.42

42-5

72.66

43.06

67.18

61.5

105-15

62.31

97-21

43-o

73-52

43-57

67.97

62.0

106.01

62.82

98.00

43-5

74-37

44.07

68.76

62.5

106.86

63-32

98.79

44-o

75-23

44-58

69-55

63.0

107.72

63-83

99-58

44-5

76.08

45-o8

70.34

63-5

108.57

64-33

100.37

45-o

76.95

45-59

7i-i3

64.0

109.43

64.84

101.16

45-5

77.80

46.10

71.92

64-5

110.28

65-35

101.95

46.0

78.66

46.60

72.71

65.0

111.14

65-85

102.74

46.5

79-51

47.11

73-50

65-5

111.99

66.36

103-53

47.0

80.37

47.62

74-29

66.0

112.85

66.87

104.32

47-5

81.22

48.12

75.08

66.5

113.70

67-37

105.11

48.0

82.07

48-63

75-87

67.0

114.56

67.88

105.90

48.5

82.93

49.14

76.66

67-5

115.41

68.39

106.69

APPENDIX.

293

Soda Ash : Table of Percentages of /Sbrfa, <0c. — (continued).

Percentage of

Degrees.

Percentage of

Degrees.

Soda.

Sodium
Carbonate.

English.

DECBOI-

ZILLES'.

Soda.

Sodium
Carbonate.

English.

DKCROI-

ZILLBS*.

68.0

116.27

68.89

107.48

73-0

124.81

73.96

H5-39

68. s

II7-I2

69.40

108.27

n-s

125.66

74-47

116.18

69.0

117.98

69.91

109.06

74.0

126.52

74-97

116.97

69- S

118.83

70.41

109.85

74.5

127.37

75-48

117.76

70.0

II9.69

70.92

1 10.64

75-o

128.23

75-99

118.55

70-5

120.53

71-43

111.43

75-5

129.08

76.49

"9-34

71.0

121.39

71-93

112.23

76.0

129.94

77.00

120.13

7-1-5

122.24

72.44

II3.O2

76-S

130.79

77-51

120.92

72.0

123.10

72.95

II3.8I

77.0

I3I-65

78.01

121.71

72-5

123-95

73-45

II4.6O

77-5

132.50

78.52

122.50

Exports of Soap and Candles.

Year.

Soap.

Candles of all Sorts.

Cwts.

Value.

Lbs.

Value.

1878
1879
1880
1881
1882
1883
1884
1885
1886
1887

335,592
383,910
391,808

353,733
409,907
391,788
476,438
402,254
426,904
451,961

£405,183
432,699
440,286
397,516
458,381
449,804

547,613
472,519
446,710
451,246

5,345,900
4,790,800
5,051,800
5,071,700

4,992,744
5,285,600
7,703,400
7,810,400
8,967,100
9,321,600

£170,161
135,852
143,231
137,677
135,051
147,961

213,635
200,179
201,919
180,912

1886

426,904 446,710 8,967,100 201,919

1887

451,961 451,246 9,321,600 180,912

Imports of Tallow and Stearin.

From

Year.

Russia.

Argentine
Republic.

United States.

Australia.

Other
Countries.

Cwts.

1878

73,646

66,754

455,991

216,722

105,820

1879

48,401

59,988

564,489

361,124

137,651

1880

25,505

103,665

516,715

492,527

178,678

1881

24,378

21,778

4I3-904 598,962

133,629

1882

33,497

128,119

291,641

434,415 | 231,167

1883

6,171

72,075

333,358

445,726

179,897

1884

14,724

97,703

332,45?

477,680

187,315

1885

7,172

107,301

241,685

410,439

243,959

1886

35,579

55,677

337,443

388,628

193,069

1887

6,532

22,209

329,367

416,658 j 120,892

294 APPENDIX.

Statistics of Soap and Candle Factories in the United
States (1880).*

No. of establishments 629

Capital $14,541,294

Average No. of hands employed :—

Males above sixteen years .... 4,368
Females above fifteen years .... 388
Children and youths 533

Total amount paid in wages during the

year $2,219,513

Value of materials $19,907,444

„ products $26,552,627

* "Report of the Manufactures of the United States (Tenth
Census, 1880)." Published 1883.

INDEX.

ABEL'S soap, 168

Abietic anhydride, 23

Acetic series of fatty acids, 54

Acidification process, 241

Acids, fatty, tables of, 54, 55

Acrylic series of fatty acids, 55

Action of soap in removing
dirt, 4

Alkalies, 23

Alkalimetry, 49

Almond oil, 20

Aluminate of soda, 31

Aluminium soap, i

Animal fats, 18

Analyses of —

carbolic soaps, 200
castor-oil soaps, 14
caustic sodium silicate, 29
cold-water soap, genuine, 169

English, 201
cotton-oil soap, 14
fancy soaps, 202
fulling soap, 163
German soaps, 201
household soaps, 202
Jarrow refined soda ash, 159
medicinal soaps, 150
Natrona refined saponifier,
32

Analyses of—

neutral sodium silicate, 29

oleic-acid soap, 159

olive-oil soap, 14

over-fatty normal soap, 154

palm-oil soap, 14

primrose soap, 106

soaps for dyeing and print-
ing, 165
for madder colours, 166

sodium aluminate, 31

tallow soap, 14

Apparatus for distillation of
stearin, 245

and arrangement of the soap

factory, 59
Appendix, 289
Arachis oil, 21
Aromatic mouth soap, 149

antiseptic tooth soap, 149
Arrangement of the soap factory,

Artificially mottled soaps, 100
Autoclave process, 248

BARKING, 72

Baume's hydrometer, 48

comparison, with specific
gravities, 47, 48

296

INDEX.

Bauxite, 31
Beech oil, 20
Berry wax, 219
Berthelot's researches, 279
Berzelius — theory of the decom-
position of soap, 5
Beyer's crushing mill, 138

hand-cutter, 136

plodding machine, 140

rotary cutter, 136
Black ash — lyes from, 24

composition, 289
.Blake and Maxwell's process for

mottled soap, 100
Bleaching bees'-wax, 213

fats, 39

palm oil, 39

tallow, 41

by bleaching powder, 41

by chlorine, 40

by Dunn's method, 41

by nitric acid, 40

by Watt's process, 39
Bock's process, 249

advantages of, 251
Boiling under pressure, 64, 86
Bone boiling, 43

Seltsam's method, 43

grease, 18

Boomer and Boschert press, 33, 34
Borax soap powder, 174
Brown-oil soaps, 156
Bye-products, 275

CABLE candles, 273

Cacao butter, 21

Calculation of proportions of fat

and alkali necessary for sapo-

nification, 55, 56
Camphorated sulphur soap, 151

Candle manufacture, 256
basting, 269

cutting and polishing, 268
dipping, 256

machine, 257
filling can, or jack, 262
machine for cutting conical

ends, 264
moulding, 258

composite candles, 267
paraffin ,, 267

sperm ,, 266

stearin ,, 266

tallow , , 265

machines, 258

Biertumpfel's, 260,

261

Cowles', 263
hand-frames, 258
scoop, 262
specialities, 271
Sweetser, Bell, and Bohm's

process, 272
wax candles, 269

tapers, 270
Candle materials, 210
animal fats, 210
fatty acids, 210
vegetable oils, 210
waxes, 210
Candle-nut tree, 208
Candles, 205

Belmont sperm and wax, 271
bending point, 274
bye-products, 275
cable, 273
coloured, 273
composite, 267
decorated, 272
definition, 205
double and treble wick, 271
exports of, 293

INDEX.

297

Candles, fatty acids for, 235

history, 234

hydraulic pressed, 271

hygienic, 272

illuminating value of, 274

King Alfred's, 206

materials for, 210

ornamental, 272

ozokerit, 271

paraffin, 267

quality of, 274

sperm, 266

spiral, 273

stearin, 266

tallow, 256, 265

twisted, 273

wax, 269

Wright's pulmonic, 272
Capacity of boilers, 61
Carnauba wax, 217
Carpenter's classification of

soaps, 8 1
Castor oil, 19

soap, 151

Caustic potash solutions, strength
of, 290

soda solutions, strength of,
291

soda lyes, 23

Characters of soap, B.P., 15
Chevreul's researches, 51
Chinese wax, 215

vegetable tallow, 217
Chlorinated soap, 151
Clarifying, 98
Classification of processes, 81

Carpenter's, 81

Wright's, 8 1
Cleansing, 83, 102
Clear-boiling, 98
Close state, 83
Cocoa-nut oil, 21

Cocoa-nut oil, imports of, 107

saponification of, 107
Coco-stearin, 232
Coction, 97
Cod-liver oil, 19
Cold process, 87

advantages and disadvan-
tages of, 88

apparatus, 64
Cold-water soap, 168

composition of genuine, 169
Colophony, 17
Colophonic acid, 23
Coloured candles, 273
Colouring for soaps, 101
Colza oil, 21
Cotton-seed oil, 19
Commercial soaps, various kinds,

88
Common salt, effect of excess

of, 85

Comparison of soaps, 201
Comparison of English and colo-
nial soaps, 202
Composition of fats, 51
Copper soap, i

Cost of yellow soap, 106, 201
Crutching, 71

machine, Strunz's, 71
Cryolite, 31
Curb, 60
Curd, 83

Curd soap, B.P. characters of, 15
Cutting soap blocks, 72
Cutting the pan, 98

D'ARCET'S method of rendering

fats, 35
Davis's alk-alumino-silicic soap,

114

298

INDEX.

Dechan on pharmaceutical soaps,

144

and Maben on the forma-
tion of soap, 53
Definition of candle, 205

soap, i
Dentier, 72

Detergent mixture, 28
Disinfecting soap (Jeyes'), 152
Dissociation by heat, 247
Drying oils, 19, 20
Doodoe nuts, 209
Dunn's method of making alka-
line silicates, 29, 115
yellow soap, 103
Duty on candles, 208
repealed, 208
soap, 3

repealed, 4

Dynamite manufacture, glycerin
for, 288

EGG oil, 1 8

Eichbaum's soap, 169

Empatage, 97

Ethereal salts, decomposition of,

53
Exports of soap and candles,

293

FANCY soaps, 117
analyses of, 202

Fat, glue, 1 8

Fats, rendering, 32

Fatty acids, 234

acidification process, 241
autoclave process, 248
Bock's process, 249

Fatty acids, dissociation by heat

process, 247
lime saponification process,

235

history of, 234

preparation of, 235
Filling can, or jack, 262
Filled soap, 15
Finishing soap, 83
Fish oils, 19

soap from, 169
Fitting, 83
Fob, 102
Frames, 68
Free acid process, 65
Fulling soap, 163

GALAM butter, 21
Gall soap, 151
Glue fat, 1 8

lime in, 39
Gossage's method of preparing-

alkaline silicates, 28
Grain soap, 10, 83
Grease, bone, 18
horse, 18
recovered, 17
Ground-nut oil, 21
Glycerin, 278

for dynamite manufacture,

288

recovery from spent lyes, 176
Allan's method, 176
Allen and Nickel's me-
thod, 176
Benno, Jappe, & Co.'s

method, 177
Clolus' method, 177
Fleming's method, 177
O'Farrell's method, 17

INDEX.

299

Glycerin, recovery from spent

lyes —

Payne's method, 178
Reynolds' method, 178
Thomas and Fuller's

method, 179
V enables' method, 179
Versmann's method, 179
Young's method, 180
removal from fats before

saponification, 280
sp. gr. of aqueous solutions

of, 280
testing, 281

Jean on, 281
Sulman and Berry on,
282

HAND, or skin, soap, 169
Hard soap, I, 90

B.P. characters of, 15
Heating soap-boilers, method of,

Heel balls, 217
Hemp-seed oil, 19
Hersey's steam pump, 66
History of candles, 205

soap, 2

Horse grease, 18
Household soaps, 90
Hydrated soaps, 107

Blake and Maxwell's process

for, 109
Hydrolysis, 6
Hydrometer, Baume's, 46

comparison of, with spe-
cific gravities, 47, 48

theory of, 45

Twaddell's, 48
Hydrometers, 45

ICHTHYOL, 155

soap, 155
Illipa oil, 21
Imports of cocoa-nut oil, 107

palm oil, 107

stearin, 293

tallow, 293

Index to size of wicks, 254
Industrial soaps, 163

calico printing and dyeing,
164

Daumas d'A116on's, 165

fulling, 163

ox-gall, 163

removing stains, 166

silk dyers', 166

throwsters', 166
Iodine soap, 151

JAPAN wax, 218

Jarrow refined ash, composition

of, 159
Jevons, Prof., on pedetic action,

4
Jeyes' disinfecting soap, 152

KILLING the goods, 82
King Alfred's candles, 206
Kingzett's definition of soap, 2

liquid soaps, 152
Kitchen stuff, 18
Koettstorfer's saponification

equivalents, 56
Kottula's compact neutral soap,

169
hand, or skin, soap, 170

300

INDEX.

LARD, 18

Large boiler process, 60

Lather, 4

Lead soap, i

Leaves, soap, 153

Liebig on behaviour of soap with

salt, 9
Lime, in glue fat, 39

saponification process, 235
Linseed oil, 20
Liquefying, 99
Liquored soap, 15
Little pan process, 60, 64
London soap powder, 174
Lye tanks, 59

testing, 26, 45
Lyes, spent, composition of, 175

Lancashire, 176

MADRAGE, 97, 99
Manganese soap, i
Manteau Isabelle, 99
Materials for candles, 210

for soap, 17
Medicinal soaps, 145

table of analyses (Dechan's),

150

Melting point of paraffin, me-
thods of taking, 229
American, 229
English, 229
Mercurial soaps, 152
Mercury soap, i
Merryweather's apparatus for

rendering fats, 38
Milling process for toilet soaps,

136-144
advantages of, 144

Mineral waxes, 219
Morfit's definition of soap, i

process for oleic-acid soap,
156

steam series, 62
Mottling, 97, 99
Myrtle wax, 219

NATEONA refined saponifier, 32

Neat soap, 102

Neutral soap, Kottula's, 169

Miahle's, 131
Night-lights, 268

OBJECTIONS to rendering fats by

open fire, 35
Oil, almond, sweet, 20

arachis, 21

beech, 20

castor, 19

cocoa-nut, 21

cod-liver, 19

colza, 21

cotton-seed, 19

Dilo, 19

egg, 1 8

ground-nut, 21

hemp-seed, 19

Illipa, 21

linseed, 20

olive, 21

palm, 22

kernel, 22
nut, 22

poppy-seed, 20

rape, 21

seal, 19

sperm, 19

INDEX.

301

Oil, sunflower-seed, 20

tallow, 1 8

Tamanu, 19

whale, 19
Oleic acid, 274

conversion of, into palmitic
acid, 274

soaps, 156
Olein, 288
Open boiling, 60
Over-fatty ichthyol soap, 155

marble soap, 155

normal soap, 154
Ox-gall soap, 163
Ozokerit, 230

refining, 230

PALM oil, or butter, 22

imports of, 107

kernel oil, 22

nut oil, 22

Paraffin, preservation of lyes by,
27

refining, 219

Tervet on, 221
Pasting, 82, 97
Pearl soap powder, 174
Pedesis, 5
Pedetic action, 5
Persoz on decomposition of soap

by water, 5
Pickling wicks, 254
Pimaric acid, 23
Piney oil, or tallow, 211
Pinic acid, 23
Pliny's account of soap, 2
Poppy-seed oil, 20
Potash lyes, 26
Potassium silicate, 29
Powders, soap, 174

Powders, borax, 1 74

London, 174

pearl, 174

soap extract, 174

washing, 174

wool-washing, 174

universal washing, 1 74
Preliminary boiling of soap, 97

treatment of fats, 32
Preservation of lyes, 27
Primrose soap, analysis of, 106
Processes —

Abel's, C. D., 168

acidification, 241

autoclave, 248

Bennett and Gibbs', 88

Blake and Maxwell's, for

hydrated soap, 109
for mottled soap, 100

Bock's, 249

boiling under pressure, 64,
86

cold, 64, 87

dissociation by heat, 247

Dunn's, 103, 115

Eichbaum's, 169

free acid, 65

Gossage's, in

Jennings', 106

Kottula's, 169

lime saponification, 235

Meinecke's, 105

Morfit's, 156

Normandy's, 115

open boiling, 60

Eadisson's, 275

Sheridan's, in

Tilghmann's, 247

Way's, 29, 114

Wilson and Payne's, 247
Properties of soap, 4

302

INDEX.

RADISSON'S process for conver-
sion of oleic into palmitic
acid, 275

Ralston' s soap slabber, 74
Rape oil, 21
Recovered grease, 17
Recovery of glycerin from spent

lyes, 175

Allan's method, 176
Allen and Nickel's method,

176

Benno, Jappe, & Co.'s me-
thod, 177

Clolus1 method, 177
Fleming's method, 177
O'Farrell's method, 178
Payne's method, 178
Reynolds' method, 178
Thomas and Fuller's method,

179

Venables' method, 179
Versmann's method, 179
Young's method, 180
Red-oil soaps, 156
Relargage, 97
Rendering fats, 32

D'Arcet's method, 35
Merry weather's superheating

apparatus, 38
objections to open fire, 33
steam cylinder process, 36
Repeal of duty on candles, 208

on soap, 4
Rosin, 17

soap, 23, 101
Roth's sand soap, 171
Rotondi on decomposition of soap

by water, 5

Rutschman's automatic
chipper, 137

Rutschman's cake-cutting ma-
chine, 142

continuous plodding ma-
chine, 141

crushing mill, 139

soap press, 143

SAL soda, 174

Salt, action of, on soap, 9, n, 12

Salted lye, 97

Salting process, 93

Salts, formation of, 50

Sand soap, 173

Sapo animalis, 147

calcis chlorinatce, 151

castil. alb., 147
mottled, 147

durus, 144

hydrargyri, 152

precipitati alb., 153
rubri, 153

mercurialis, 152

rnollis, 148

piceus, 153

terebinthinas, 153
Saponification, 50, 82

equivalents, 57, 58

under pressure, 86
Saponifier, Natrona refined, 32
Savon au bouquet, 132

a 1'huile de canelle, 132

au fleur d'oranger, 132

au muse, 133

4 la rose, 133

a la vanille, 1 33
Savonettes, 133

camphor, 134

honey, 134

mottled, 134

sand, 134

INDEX.

303

Savonettes, violet, 134
Scheurer on soaps for calico

printing and dyeing, 164
Scribe, 72
Seal oil, 19
Separation of soap by salt, 1 1

by strong lye, 1 1
Separation of stearic and oleic

acids, 252

Setting point of tallow, 211
Shanks' method of preparing

lyes from black ash, 25
Shaving paste, 1 34
Shea butter, 2 1
Silicates, preparation of, 27-29

Sheridan's process, 27

Gossage's ,, 28

Dunn's „ 29

Way's „ 30

Silk dyers' and throwsters' soap,

166

Silver soap, I.
Soap, Abel's, 168

action of, in removing dirt, 4

alk-alumino-silicic, 114

almond, 129
bitter, 130

aluminium, i

ammoniated, 129

aromatic mouth, 149

antiseptic tooth, 149

beef marrow, 130

Berzelius— theory of decom-
position of, 5

boilers, 60

brown-oil, 156

caldrons, 60

calico printing and dyeing,
164

camphorated sulphur, 151

carbolic, 200

Castile, 97

Soap, castor-oil, 151

characters of, B.P., 15

chlorinated, 151

cocoa-nut-oil, 107

cold-water, 168

copper, i

curd, 90

B.P. characters of , 15
English method, 90
German „ 93, 95

definition of, i

disinfecting (Jeyes5), 152

domestic, 90

duty on, repeal of, 4

Eichbaum's, 169

extract, 174

fancy, 117

filled, 15

floating, 130

fulling, 163

gall, 151

glycerin, 127, 130

grain, 10

hard, i

characters, B.P., 15

history, 2

honey, 130

household, 90

hydrated, 107

hydrolysis of, 6

ichthyol, 155

industrial, 163

iodine, 151

Jevons on pedetic action, 4

kettles, 60

Kingzett's definition of, 2

Kottula's, 169

lard, 131

lather, 4

laundry, go

lead, i

leaves, 153

304

INDEX.

Soap, Liebig on behaviour of,

with salt, 9

liquid (Kingzett's), 152
liquored, 15
madder colours, 166
manganese, i
marine, 107
Marseilles, 97
medicinal, 145
.mercurial, 152
mercury, i
Miahle's neutral, 131
Morfit's definition of, I
mottled, 96
oleic-acid, 156
olive-oil, 97
opaque toilet, 121
ox-gall, 163
pans, 60

pedetic action of, 5
Persoz on behaviour of, with

water, 5

Pliny's account of, 2
preparation of, in small

quantities, 171
properties of, 4
red-oil, 156
removing stains, 166
repeal of duty on, 4
Kotondi on action of, 5
samphire, 132
sand, 171, 173
separation of, by salt, 1 1

by strong lye, 1 1
silicated, in, 115
silk dyers' and throwsters',

1 66

silver, i
slabber, 73, 74
sodium aluininate, 173
soft, i, 159

characters of, B.P., 15

Soap, soft —

Gentele's method, 162
Russian ,, 162
Scotch ,, 161

Starkey's, 153
suds, 4

sulphated, 115
tannin, 153
tar, 153
taxation of, 3
tin, i
toilet, 117
transparent, 124
turpentine, 153
Unna's, 153
Venetian, 97
watered, i$
Whitelaw on action of salt

on, 12

Windsor, 135
Wright and Thompson on

hydrolysis of, 6
Wright's definition of, 2
wych -hazel, 155
yellow, 101

cost of, 106, 201
zinc, i

Soda ash, lyes from, 23
Sodium aluminate, 31

soap, 173

ichthyosulphate, 155
silicate, 27

composition of, 29
Soft lyes, 97

soap, i, 159
Soluble glass, 27
Spent lyes, composition of, 175
Lancashire, 176
recovery of glycerin from,

175

Sperm oil, 19
Spermaceti, 19, 215

INDEX.

305

Stains, soap for removing, 166

Stamping soap, 77

Steam lyes, 26

series (Morfit's), 62
twirl ,, 156

Strength, 161
false, 161

Stearin, 231

Stone-wax, 217

Sunflower- seed oil, 20

Sylvic acid, 23

TALLOW, 18

oil, 18

Tamanu oil, 19
Taxation of soap, 3
Tannin soap, 153
Tar soap, 153

Tervet on refining paraffin, 221
Testing soaps, 181

Cailletet's method of deter-
mining fatty acids, 192
determination of carbolic

acid, 197
of cost of soap from

analysis, 201
of glycerin, 193

Muter 's method, 195
estimation of detergent

value, 191

Filsinger's scheme, 187
free alkali, 182, 184, 187,

189, 200

Leeds' method, 182, 185
Owens College scheme, 188
sampling, 181
Testing soda ash, 27

lyes, 26, 45

Theory of hydrometer, 45
Tin soap, i

Toilet soaps, 117
apparatus, 117
by cold process, 125
by remelting, 123
by French system, 136
formulae for, 129
French system —

crushing and grinding,

137

cutting, 136

into cakes, 142
plotting, 140
stamping, 142
manipulation, 120
materials, 117
moulding, 119
opaque, 121
savonettes, 133
transparent, 124
Train oil, 19
Turpentine soap, 153
Twaddell's hydrometer, 48

UNIVEESAL washing powder,

174
Unna's soaps, 153

VEGETABLE oils, 19-22

WASHING powder, 174
Water, 32
Watered soap, 15
Way's process for alkaline sili-
cates, 29
Whale oil, 19

306

INDEX.

Whitaker's patent soap frame, 68 i
Whitelaw on the action of salt j

on soap, 12
Wicks, 253

pickling, 254

size of, 254

index to, 254
Windsor soap, 135

brown, 135

ordinary, 135

rose, 135

violet, 135

Weise's formula for, 135
Wool-washing composition, 174
Wright and Thompson on hydro-
lysis, 6

Wright's classiLcatiou. of soaps,

, 8l

definition of soap, 2

Wych-hazel soap, 155

YELLOW soap, 101
cost of, 106, 20 1

ZALMON'S aromatic mouth soap,

149
Zawierciers soap for dyeing and

printing, 165
Zinc soap, i

PRINTED BV BALLANTYNE, HANSON AND CO.
LONDON AND EDINBURGH

RET

Thi

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