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Full text of "Chemistry simplified : a course of lectures on the non-metals based upon the natural evolution of chemistry, designed primarily for engineers"

CHEMISTRY SIMPLIFIED. 



CHEMISTRY SIMPLIFIED. 



A COURSE OF LECTURES ON THE NON-METALS, 

BASED UPON THE NATURAL EVOLUTION 

OF CHEMISTRY. 



DESIGNED PRIMARILY FOR ENGINEERS. 



GEORGE AUGUSTUS KOENIG, Ph. D., A. M., E. M., 

PROFESSOR OF CHEMISTRY, MICHIGAN COLLEGE OF MIXES, HOUGHTON, MICHIGAN. 



ILLUSTRATED BY ONE HUNDRED AND THREE ORIGINAL DRAWINGS. 




PHILADELPHIA : 
HENRY CAREY BAIRD & CO , 

INDUSTRIAL PUBLISHERS, BOOKSELLERS AND IMPORTERS, 

No. 810 WALNUT STREET. 
1906, 




COPYRIGHT, BY 

GEORGE AUGUSTUS KOENIG, 
1905. 




PEEFACE. 

IN these lectures to mature beginners in Chemis- 
try, the fundamental idea has been followed to 
unroll before the student the knowable nature of 
bodies as an ever-growing and spreading picture, 
and not as a finished work handed down by the 
great masters. When I say mature beginners, I 
mean that in my estimation chemistry should not 
be taught at all to boys and girls before their full 
mental growth has been attained, fully aware of my 
isolated position in the present evolution of schools. 
Only the mature mind follows with growing interest 
the unfolding of such a picture, and absorbs it as a 
living thing. 

In following this fundamental idea, the usual 
systematic classification .had to be abandoned. It 
will be seen that the beginning is made with bodies 
of familiar acquaintance such as the common metals, 
but these metals are not postulated as elements or 
simple bodies ; they are merely objects for experi- 
mentation in allowing the equally familiar bodies 
of air and water to act upon them under the familiar 
impulse of heat. Noting the changes thus wrought, 
the mind questions and seeks answers. Answers 
come by carefully laid experiments, but always in 

(v) 



295603 



VI PREFACE. 

such a way that no agent of unfamiliar nature is 
called in to aid. Such a scheme is essentially his- 
torical, for the successive generations of chemists 
have been working in exactly this way. They saw 
and raised questions. Their answers, being pre- 
mature in so far as they brought into play unknown 
agents, were often wrong, had to be set aside and 
much modified by subsequent investigations. Thus 
also in these lectures, questions are raised, but not 
answered at once, although perfectly well known, 
because the student's knowledge has not reached 
the required fullness. In the chapters on green 
vitriol and on common salt, as well as on potash, 
the reader will find the application of the funda- 
mental idea fully elaborated. 

Generalizations from the experiments are always 
drawn, though I have avoided the term law. The- 
orizing upon molecules and the structure of mole- 
cules, ions and electrons I have omitted altogether. 
No beginning student can be capable of drawing 
inferences for himself concerning these matters. 
They should only be brought before the student at 
the end of his school work, if he intends following 
chemistry. To bring them before proposing en- 
gineers, seems unnecessary, if not unwise, and these 
lectures are delivered to engineering candidates, 
more especially mining engineers and metallurgists. 
To them the theories can be of no help. They want 
to know the practical consequences which must 
follow from the presence of certain material condi- 
tions. They must be trained to inquire, and de- 



PREFACE. Vll 

duce from given conditions. The chief tendency 
of the lecture course is to evoke in the student the 
constant thought of Why ? together with the love 
for the experiment. The course extends over seven 
months and one-half, in three lectures a week. It 
is supplemented by laboratory work of eight hours 
per week in which some fifty-odd experiments, se- 
lected from the lecture experiments, are performed 
by the student. The chemistry of the metals in 
conjunction with qualitative analysis comprises the 
second year's work of equal time-extension, but only 
two lectures a week. 

The illustrations are made with the chief aim of 
engineering simplicity. Thanks are duly given to 
each and every chemist who has given a laborious 
life in contributions with which to build up the 
chemistry of to-day. 

THE AUTHOR. 

HOUGHTON, MICHIGAN, November 15, 1905. 



CONTENTS. 



CHAPTEE I. 

THE NATURE OF AIR AS A MIXTURE OF GASES. 

Introductory remarks 1 

The nature of air . - - 3 

Deductions ; How much air will be absorbed by a given weight 

of copper ? 5 

How much air will be absorbed frcm a given volume of copper? 7 

Calibration of the apparatus 8 

Deduction . . 11 

Ozone and azote ; Weights of air, nitrogen and ozone ; Sulfur . 13 

Is the burning of sulfur similar to the scale-forming of copper? 14 

Use of litmus ; Acids ; Definition of an oxyd 15 

General deductions ; A deoxydizing substance, carbon .... 16 

Metals and non-metals 17 

CHAPTER H. 

THE NATURE OF WATER. 

The ancient version of things ; The kinds of water 18 

Physical properties of water 19 

Chemistry 21 

Action of steam on iron and zinc 22 

On copper ; Keverse proof 23 

Hydrogen ; Electrolysis 25 

Oxygen ; Deductions ; Inverse proof . 31 

Explanation of action ; Law ; Idea of an atom 33 

Hydrogen peroxyd 34 

CHAPTEE III. 

GREEN VITRIOL OR COPPERAS. 

Description 35 

Chemical investigation ; Deduction 37 

(ix) 



X CONTENTS. 

PAGE 

Presence of sulfur established ; The oil of vitriol ....... 40 

Preparation of a quantity of the oil 41 

Investigation of the oil 43 

A different oil 44 

Work with this other oil, the liquid residue 45 

A higher oxyd of sulfur 46 

Action of the liquid residue on lead and silver . 47 

Investigation of the white fumes that crystallized 49 

Summary ; Direct proof of the presence of water in the liquid 

residue, the sulfuric acid 50 

Proof of the volume composition of the sulfur oxyd, SO 2 ... 52 

The dilution of sulfuric acid 54 

Molecular weight ; Hydrates of sulfuric acid . 55 

Action of sulfuric hydrates on the metals 56 

The iron vitriols. 58 

Preparation of sulfur dioxyd 59 

Generation of hydrogen 61 

Koenig's generator 62 

CHAPTER IV. 

THE LEPSON OF LIMESTONE. 

The lime minerals 64 

Action of heat on calcite 65 

Partial proof of the lime gas 67 

Study of the residue 70 

Formation of lime hydroxyd 71 

Action towards acids . . . . , 72 

Action of the lime gas upon the lime hydroxyd ... . . 73 

Deduction . . 74 

Summary of the limestone lesson 75 

CHAPTER V. 

THE LESSON OF WOOD ASHES. 

Wood and coal ashes 76 

Potash ; Investigation of the lye 77 

Potassium hydroxyd 79 

Hydrates 80 

Proof of the hydroxyd nature of solid caustic potash 81 



CONTENTS. XI 

PAGE 

Action of the preceding substances on the vitriol solutions . . 82 

Potassium . . . 84 

Physical and chemical properties of potassium * 87 

Use of potassium in finding the non-metal in gas from limestone. 88 

Alkaline substances 91 

CHAPTER VI. 

THE LESSON OF COMMON SALT. 

Forms of natural salt * 92 

Investigation . 93 

Work with the salt gas . 94 

Chlorine . ... . . . 98 

Preparation of chlorine. . . . 99 

Chemical properties of chlorine 104 

Chlorate . ... 105 

Process for making potassium chlorate ; Composition of salt gas. 106 

Properties of hydrogen chlorid 107 

HC14-water . . 108 

Advantages of different driers Ill 

Acid hydrometers 112 

The discovery of the metal sodium, by working with the salt 

cake 113 

Physical and chemical properties of sodium 116 

Oxyds of sodium 118 

CHAPTER VII. 

THE STORY OF SODA ASH AND LEBLANC. 

The Leblanc soda process 119 

Sodium carbonate and bicarbonate 121 

Caustic soda ; Lye balls ; Kelp 122 

CHAPTEK VIII. 

ON THEORIES, COMBINING WEIGHTS, ATOMIC WEIGHTS 
AND VALENCES. 

A uniform system of writing formulas 123 

The idea of radicals . 124 

The electrochemical series ; Valence 12 



Xll CONTENTS. 

PAGE 

The atomic weights of the elements ; Molecular weights and 

volume weights . . - 126 

Hydroxyl radical ; Sulfate instead of vitriol 129 

Atomic weights of calcium, copper, lead and zinc ...... 130 

Atomic weights of silver and gold . . . 131 

Relation between atomic weights and specific heats of the ele- 
ments 132 

Law of Dulong and Petit ; Review of the action of chlorine on 

the alkaline hydroxyds 133 

Dichloroxyd ... 134 

Chlorates. ... 135 

Oxygen from chlorates .... 136 

CHAPTER IX. 

BROMINE, IODINE, FLUORINE. 

Bromine from the mother liquor of the salt works 137 

Compounds and actions of bromine ... 138 

Iodine 139 

Properties of iodine ; Starch and iodine 141 

Compounds of iodine 142 

General remarks 143 

Ismorphous substances ; Fluorine 144 

Flux 145 

Investigation of the fluorite gas 146 

Composition of the gas 148 

The etching process 149 

The nature of fluorine ; The metal in fluorspar 150 

CHAPTER X. 

LECTURE ON NITER OR SALTPETER. 

The kinds of niter 152 

Solubility ; Investigation of the soda niter 153 

The nature of nitrogen 154 

The spirits of niter 155 

Aqua regia 156 

The properties of nitrogen 159 

Properties and composition of spirits of niter 160 

Nitrates , 164 



CONTENTS. Xlll 

PAGE 

Gunpowder 166 

Calculations on the explosive power of gunpowder 168 

Other powders ; Investigation of the nitrous fumes 170 

Nitrogen dioxyd 171 

Nitrogen monoxyd 176 

Proof that the formula is NO 177 

Properties of NO 178 

The ring test for nitrates 178 

Nitrites . . 179 

Preparation of KNO* . 180 

Dinitrogen trioxyd 181 

Nitrite test, using starch and iodine compound ; Laughing gas . 182 

Properties of N 2 O 183 

Preparation of the gas on a large scale 184 

Recapitulation of the oxyds of nitrogen 185 

CHAPTER XL 

AMMONIA, A VOLATILE ALKALI. A COMPLEX METALLIC RADICAL. 

The nascent state ; Ammonia. 186 

Investigation 187 

Preparation of ammonia 188 

Sal-ammoniac 189 

Composition of ammonia 190 

Proof that hydrogen is contained in ammonia 191 

Proof that ammonia contains no oxygen ; Demonstration that 

the formula is NH 3 192 

The chemical nature of ammonia 194 

Ammonium ... 195 

Indirect proof of the ammonium theory . : 196 

Formation of ammonium compounds 197 

Liquid ammonia 200 

Preparation of ammonia water 201 

Carbonates 203 

Sal-ammoniac 204 

Soldering, with use of sal-ammoniac . - 205 

Solvay process , 206 



XIV CONTENTS. 

PAGE 

CHAPTER XII. 

ORIGIN AND OCCURRENCE OF NITER. 

Sources of nitrogen . 209 

Niter plantation 210 

The Chili niter deposits 211 

The origin of the deposit 212 

Conversion of soda niter into potash niter 213 

CHAPTER XIII. 

THE MANUFACTURE OF HYDROGEN SULFATE OR SULFURIC ACID 
ON A COMMERCIAL SCALE. 

Direct proof that H 2 SO 4 results from the union of SO 3 with H 2 O . 216 
Cost of the sulfur-nitric acid method ; The SO 2 -nitric acid 

method 217 

The lead chamber process. 218 

Sulfur from pyrite 219 

The plant needed 220 

The Glover tower 222 

Size and cost of plant . 224 

The Gay-Lussac tower 225 

The Lunge-Rohrmann plate column 226 

Concentration of the chamber acid ...... 227 

The Gridley system ; Lemaire and Co.' s stills 228 

Loss of platinum; Manufacture of oil of vitriol by Winkler's 

method . t . . . . 230 

The direct contact method 231 

CHAPTER XIV. 

OTHER COMPOUNDS OF SULFUR. 

The sulfid ores 233 

Hydrogen sulfid 234 

Proof of the formula, H 2 S 235 

Generation of H 2 S in a steady current at a minimum of cost . 236 

Properties of H 2 S ,237 

Action of H 2 S on KOH 239 

ActionofH 2 8onNaOH;OnCa(HO) 2 240 

Calcium monosulfid 241 



CONTENTS. XV 

PAGE 

Action of sulfur on the alkaline hydroxyds 242 

Sodium hyposulfite and its manufacture 243 

Test for thiosulfate 244 

Action of H'S upon solutions of metallic salts 245 

Examination of the precipitates obtained 249 

Hydrogen persulfid 253 

Sulfur chlorid and carbon disulfid 254 

CHAPTER XV. 

CARBON COMPOUNDS; ORGANIC BODIES. 

Native carbon 257 

Coal 258 

Carbon dioxyd 259 

Chemical properties 260 

Composition of CO S 261 

The atomic weight of carbon ; Carbon monoxyd , . 262 

Proof of the composition of CO 263 

Structure of plants . . . 264 

Experiments with cellulose 265 

The formula of cellulose derived from the results of combustion. 266 

Parchment 270 

Xitro-cellulose, gun-cotton 271 

Gun-cotton as an explosive 272 

Destructive distillation of wood 274 

Charcoal ; Pyroligneous acid 276 

Acetic acid 278 

Wood tar 279 

Carbolic acid ; Picric acid 282 

Paraffin .... 283 

Analysis of wood gas 284 

Marsh gas, methane 294 

Safety lamp 300 

The theoretical importance of marsh gas . 301 

The marsh gas or paraffin series of hydro-carbons 302 

Propane ; Butane ; Isomerids 303 

Pentane . . 304 

Carbonyl-hydroxyl ; Wood subjected to pressure and heat. . . 305 



XVI CONTENTS. 



CHAPTER XVI. 

MINERAL COAL AND ITS CHEMISTRY. 

The kinds of coal 308 

Composition of coal 310 

Ultimate composition 311 

Proximate composition ; Origin of coals 312 

The coking process 316 

Coke 318 

Coal tar ; Naphthaline ; Nitrobenzol . 320 

Anilin ; Complex base ; Methylanilin 321 

Rosanilin ; Mauvanilin 322 

CHAPTER XVII. 

THE GASES FROM THE DISTILLATION OF COAL ; THE MANUFACTURE 
OF ILLUMINATING GAS AND GAS COKE. 

The qualitative composition of the coal gas 324 

Dissociation at high temperatures ; Plan for gas works .... 325 

The dimensions of the plant 329 

Water-gas 331 

Fuel-gas 333 

Rock-oil, petroleum . . 335 

Chemical properties ; Refining of the crude oil 336 

The flash-point ; Natural gas . 337 

CHAPTER XVIII. 

THE HOMOLOGUES OF CELLULOSE STARCH, DEXTRIN, SUGARS. 

The wheat grain 339 

Starch 340 

Chemical properties of starch ; Dextrin 341 

The sugars ; Cane sugar 342 

Grape sugar 343 

Fruit sugar 344 

Milk sugar ; Gum arabic 345 

CHAPTER XIX. 

ALCOHOL, SPIRITS OF WINE, ETHYLHYDROXYD. 

The production of alcohol 346 

Fermentation ; Yeast 347 



CONTENTS. XV11 

PAGE 

The manufacture of ethyl alcohol 348 

Absolute alcohol 349 

Properties and chemical constitution of alcohol 350 

CHAPTER XX. 

SOME IMPORTANT DERIVATIVES OF ALCOHOL. 

Ether, ethyl oxyd 352 

Chloroform . . 353 

lodoform ; Aldehyde ; Chlopal ... 354 

Mercuric fulminate; Preparation of the fulminate 355 

Manufacture of percussion caps 356 

Silver fulminate 357 

CHAPTER XXI. 

SOME ORGANIC ACIDS. 

Formic acid and acetic acid 358 

The manufacture of vinegar 360 

Oxalic acid 361 

Chemical properties ; Methods of manufacture 363 

Lactic acid and tartaric acids 364 

Tartar emetic 365 

Citric acid ; Malic and tannic acids ' 366 

Ink 367 

Leather 368 

Gallic and pyrogallic acids 369 

CHAPTER XXII. 

THE VEGETABLE FATS AND ANIMAL FATS. 

Plant oils 370 

Animal fats 371 

Chemical action of fats 372 

Glycerin 373 

Manufacture of glycerin 374 

Tri-nitro-glycerin ; Dynamite 875 

Manufacture of nitro-glycerin ; Tallow 376 

Soap ; Drying oils . 377 

Turpentine 378 

Rosin .379 



XV111 CONTENTS. 

PAGE 

Eubber 380 

Vulcanizing of rubber ; Ebonite. . 382 

CHAPTER XXIII. 

ORGANIC ALKALOIDS. 

Theobromin ; Caffein ; Urea ; Morphin 383 

Chinin ; Strychnin; Brucin and Atropin 384 

Cocain ; Nicotin 385 

CHAPTER XXIV. 

ALBUMEN AND ALBUMENOIDS 

Albumen 386 

Haemoglobin ; Haematin 387 

Fibrin ; Casein ; Horn, hair and skin 388 

Distillation of albumenoid substances 389 

Neat's-foot oil 390 

CHAPTER XXV. 

ORIGIN OF CYAN IDS. 

The discovery of the yellow prussiate of potash 391 

Potassium ferrocyanate 392 

Potassium cyanid and its preparation 393 

Chemically pure potassium cyanid 394 

Hydrogen cyanid ; Prussic acid 395 

Preparation of prussic acid and of cyanogen ; Composition of 

cyanogen ; Sulfocyanogen and sulfocyanates 397 

Potassium ferricyanate 398 

Potassium cyanate ; Cyanuric acid 399 

Fulminic acid 400 

CHAPTER XXVI. 

BONE-ASH AND PHOSPHORUS. 

Bone-ash 401 

Experiments on the bone-ash 402 

The discovery of phosphorus "..._.. 404 

The modifications of phosphorus ... 405 

Red phosphorus 406 

Black phosphorus ; The atomic weight of phosphorus ; Phos- 
phorus pentoxyd 407 



CONTENTS. XIX 

PAGE 

Preparation of phosphorus pentoxyd ; Orthophosphoric acid. . 408 

Preparation of the ortho-acid ; Orthophosphates 409 

Microcosmic salt. . - 410 

Insoluble orthophosphates ; Molybdate test 411 

Pyro- and metaphosphoric acids and their preparation .... 412 

Phosphorus trioxyd ; Phosphorous acid 413 

Hypophosphorous acid ; Phosphorus trichlorid .... . 414 

Phosphorus pentachlorid ; Phosphine 415 

Preparation of phosphine 416 

Composition of phosphine ; Phosphonium 417 

Liquid hydrogen phosphid ; Metallic phosphids 418 

APPENDIX. 

The chemical elements, their symbols, equivalents, and specific 
gravities 419 

Table for the comparison of the scales of Reaumur's, Celsius's, 
and Fahrenheit's thermometers 421 

Rules for the conversion of the different thermometer degrees 
into each other 422 

Table of the liter weights of gases 423 

INDEX . . 425 



\ 



Of THE 

ERSITY 

OF 
IFQR1 



CHEMISTRY SIMPLIFIED. 



CHAPTER I. 

THE NATURE OF AIR AS A MIXTURE OF GASES. 

INTRODUCTORY REMARKS. I show you this small 
copper ingot. It was made by pouring liquid cop- 
per, at a yellow heat, into an iron mould. You 
notice a bright red color on the sides and bottom, a 
dark reddish-gray on the upper side, and a pale 
yellowish-pink on this spot which I scrape with the 
knife. By drilling a hole through the ingot, or by 
sawing it into two we find the pale, soft yellow- 
ish-pink color persistent throughout the interior. 
Hence we infer that the yellowish-pink is the true 
color of copper, while the red and gray-red at the 
outside must be due to a change which happened 
to the ingot during the time when it passed from 
yellow heat to the temperature of the room. If we 
do not take this change as a simple matter of fact, 
but if instead we ask for the reason of the change, 
then our mind is scientific, it is above the average, 
and there is hope for us. Now there are two ways 
for satisfying this desire for the reason for things. 
Along one way we just ask the nearest man or the 
handiest book, along the other way we set to work 
it out ourselves. Following the second and much 
harder road, we become investigators and inventors. 



2 CHP;MISTRY SIMPLIFIED. 

You have come here to learn chemistry, and my 
duty is to show you the way. I may lead you 
along the first trail by means of a book and recita- 
tions and my own acquired knowledge of the nature 
of things. However, I choose to take you by the 
second trail, difficult in steep slopes and rapid 
descents, but which will ultimately take you, when 
the pass shall have been won, into the beautiful 
valley of intellectual satisfaction and fruitful tech- 
nical invention. Some may get exhausted on the 
journey, and some may not have the right eyes to 
see, the right hands to grapple with the difficulties ; 
for them of course there is no hope and they must 
take the other trail, they will not become leaders in 
the profession. Those who are born with right 
desire will ultimately get to the goal by any road 
whatsoever ; but they will have spent much time, 
much energy, in doing useless things. My object, as 
your teacher, is to point out things to you so that you may 
save the waste and arrive much more rapidly at the pass. 

Let us return to our ingot and ask : What causes 
the copper to be of different colors on the outside 
from the inside ? This question we name, by gen- 
eral consent, a chemical question because the change 
which happened to the outside of the ingot is a per- 
manent change, by which the substance has acquired 
different properties throughout. If I bend this wire 
there is also a permanent change, but it is only a 
change of shape, the copper itself has not changed 
any of its properties. If we inquire about this 
change of form in the new positions of the copper 



NATURE OF AIR AS A MIXTURE OF GASES. 

particles, we have to deal with a proposition in 
physics. There are, of course, many changes in 
which physics and chemistry overlap, when we must 
enter into both sciences. It is merely a matter of 
convenience, for the sake of more effective work 
that this division into physics and chemistry has 
been made. One set of men pursue the one set of 
phenomena, becoming more expert in observation 
than if they spread themselves over both sets. 

1. The nature of air. 

Pursuing the question concerning the changes at 
the surface of the copper ingot, we shall now insti- 
tute experiments, every one of which will give rise 
to new questions. 

In Figs. 1, 2, 3, 4 the trial arrangements are set 
up to meet those questions. 

In Fig. 1, a bright piece of sheet copper A is 
placed within the non-luminous or purplish part of 
the flame F. It is evident that here the metal will 
be exposed to the action of heat, to the action of air 
and to the action of the substance of the flame. 
The metal at bright red heat, under these condi- 
tions covers itself with a dark scale, which peels off 
and is found to be very brittle. In Fig. 2, the metal 
A is within the hard-glass tube T, which is closed 
at one end, open at the other end. The substance 
of the flame does not come in contact with the metal, 
but the heat of the flame is conducted through the 
glass, the metal becomes red hot and covers itself 
with a very thin film. Here the air has access, but 



4 CHEMISTRY SIMPLIFIED. 

limited. Fig. 3, shows the metal strip A within a 
tube T. The tube was then drawn out at (7, leaving 
a narrow neck, was then connected with an air 
pump until all air was drawn out, when the neck 
C was allowed to close up by means of a sharp, hot 
flame (blow-pipe flame). If then the tube T be 



FIG. l. 
A 




FIG. 2. 





made red hot in the flame jP and kept so for any 
length of time, we find, on cooling, that no change 
has taken place, the copper is bright with its fine 
pale yellowish-pink color. Lastly in Fig. 4, we have 
the copper strip in a glass tube which is open at 
both ends. Owing to inclined position a lively air 
current will set in in the direction of the arrows as 



NATURE OF AIR AS A MIXTURE OF GASES. O 

soon as the tube is heated by the flaine. We find 
quickly that the last conditions produce the most 
change on the copper the most rapid development 
of the scale. 

Deduction from the four experiments: 1. Copper 
takes from the air, at red heat, a portion of the air 
and changes to a brittle scale. 2. The substance of 
the flame does not enter into this change, only the 
heat of the flame. Two questions now suggest 
themselves : 1. How much will be absorbed by a 
given weight of copper? 2. How much of a given 

FIG. 5. 




_L_L 



volume of air will be absorbed ? In order to an- 
swer the first question rig an apparatus as shown 
in Fig. 5, where T is an infusible glass tube (so- 
called combustion tube) not less than J" inside 
diameter. The tube is bent over the blast lamp. 
Place the tube in a horizontal position by means of 
clamp-stand 5. Select a porcelain boat sufficiently 
narrow to pass into the tube easily. Clean and 
weigh the boat. We choose glazed porcelain 
because it will not become soft except at white heat, 
because it does not change in weight when heated 



6 CHEMISTRY SIMPLIFIED. 

in air. Place into this boat about 0.100 grain of 
copper filings, that is to say you must take the 
weight very accurately. But it does not matter 
whether you take 0.095 or 0.102, only by taking 
0.100 accurately you will save figuring the percent- 
age. You are told to take filings, because in this 
form, the metal will be exposed with a maximum 
of surface and a minimum volume, which is most 
desirable, since the intended action proceeds from 
the surface. Shove the boat into the tube as shown 
in the figure, and place the lamp so that the entire 
length of the boat can be brought to redness. The 
bent part of the tube being bent upwards, a so-called 
draught will arise as by a chimney, because a col- 
umn of hot air being in the vertical tube, this hot 
air being lighter than the cold outer air, the latter 
will pass in at the lower end and push out the warm 
air, hence a steady air current will pass through the 
tube in the direction of the arrow's pointing. Allow 
this action to proceed for 30 minutes. Do not for- 
get to place a few fibres of infusible asbestus between 
the tube and the boat, for the tube may become 
soft and cause the boat to stick. Should the tube 
exhibit a tendency to sag you will prop it up at the 
end by means of a piece of brick. Remove the 
flame at the expiration of the half hour, let the tube 
cool down until it can be held in the hand.' Pull 
out the boat and weigh. Return the boat to the 
tube, replace the lamps and work for another half 
hour. Then weigh again. If the second weight is 
not equal to the first, you cannot be certain that the 



NATURE OF AIR AS A MIXTURE OF GASES. 7 

copper has saturated itself, and a third period of 
heating becomes necessary, and perhaps a fourth 
until you get constant weight. Many trials, made 
with greatest care, show that 0.100 copper will in- 

FIG. 6. 




crease to 0.1254 and no further, and thus the result- 
ing dark gray-black product of change will contain 
in 100 : Copper 79.6 and air 20.4. 

2. How much will be absorbed from a given volume 
of air f 

For an answer to this question let an apparatus 



8 CHEMISTRY SIMPLIFIED. 

be rigged as in Fig. 6. We must make provision 
to pass and repass the same volume of air over the 
heated copper without any air coming from the 
outside, nor any air escaping to the outside. Let 
T again be of hard glass i or -^ inch internal diam- 
eter and 5 inches long. Introduce a roll of fine 
copper gauze, 5, then bend the tube into a double L. 
Paste on a mark at M. Determine or gauge the 
volume of the tube by filling it with mercury up to 
the mark M, and then weigh the mercury. If the 
weight of the mercury be g, then g 1 13.6 = F(in cubic 
centimeters). Provide two soft glass tubes, S, &', 
with stoppers, the upper ones to receive the tube T, 
the lower ones to receive narrow glass tubes, which 
are connected by rubber tubing, 2, h with the glass 
syphons 1, 3. These stand in beaker glasses, R, R'. 
Calibrate the tube S into cubic centimeters, the 
lower side of the upper stopper forming the mark. 
Calibration. Stand 8 upside down, after a solid 
stopper 1, Fig. 7, has been pushed into the mark. 
Then weigh out (to 0.1 gram) 5 X 13.6 = 68.0 grams 
of mercury and pour this into the tube. Make a 
scratch (with a glazier's diamond, with a sharp 
splinter of quartz, or with a hard file) tangent to 
the meniscus. Measure the distance from to 5 
with a scale or pair of dividers. Lay this distance 
down a strip of white paper and divide into 5 equal 
parts. Lay on these divisions beyond five for the 
whole length of the tube. Then paste the strip 
upon the tube so that the marks fall together, 
and then cover the paper on the outside with molten 



NATURE OF AIR AS A MIXTURE OF GASES. VJ 

paraffin. Thus your tube is calibrated into cubic 
centimeters. Weighing out a defined quantity of 
mercury is not quite so easy as it sounds. Proceed 
as follows : Place a very small beaker glass upon 
a so-called pulp balance (it were foolish to use a 
fine balance because we only want to weigh as close 
as 0.1 gram). Why ? Because 0.1 gram of mer- 




cury corresponds to less than 0.01 cubic cent., and 
we do not care to read a volume closer than 0.1 
cubic cent. It would in fact be quite sufficient 
accuracy if we got any weight of mercury within 
1.0 gram. Make a pipette with capillary outlet by 
drawing out an 8" x J" soft glass tube over the 
lamp flame as shown in Fig. 8, and cut off with file 
at point a. Fill this tube by sucking with mer- 
cur\ T , and let this latter flow into the beaker, until 
the balance tips. The beaker has been previously 
balanced by shot, and the required weight, 68 grs., 
has been placed upon the weights' pan. The first 
finger closes the upper end of the tube at the 
moment of tipping. After the apparatus (Fig. 6) 



10 CHEMISTRY SIMPLIFIED. 

has been set up the tubes S, S' being held in 
place by clamp-stands or tripods or under prop- 
pings the beaker glasses R, R' are filled with 
water, the syphons 1, 3 are filled by sucking at 
the end of the detached rubber tubing until the 
water comes to the mouth, the rubber being then 
joined to the tubes S, S'. R' is then raised upon 




blocks until the water reaches the mark M, while 
R is lowered until its water level falls together 
with a division of the scale on S, say for in- 
stance 10. We are having then a volume of air V 
equal to 10 plus v (v being volume of tube T). 
Let v be 5 c.c. for example ; then the total volume 
will be 10 pins 5 equal 15 c.c. Bring now the 
burner B under T so that the copper gauze 5 be- 
comes red hot. Cause the air to move slowly over 
the hot copper, by lowering beaker R and raising 
R at the same time. Repeat this movement 10 
times. Then remove the burner and let the tube 
T return to the temperature of the room. Bring 
the water to the mark M and adjust R in such a 
way that its water-line and the water-line in S fall 
into one level. On reading off the position of the 
water-line 8 on the scale, we will read 7, that is, 
3 c.c. of air have disappeared ; 15 c.c. of air have 
lost 3 c.c., 5 c.c, have lost 1 c,c. Bring the flame 



NATURE OF AIR AS A MIXTURE OF GASES. 11 

back and again pass 10 times over the hot copper. 
On cooling will find the same result as before ; 
hence the loss of the air, under these conditions, is 
constant. 

Deduction. Air is composed of at least two parts, 
which possess each decidedly different properties, or 
in other words : Air consists of two different gases. 
Now it is well known that men and animals must 
have air to breathe. Query? Which one of the 
two gases do they require, or do they need both? 
As the one gas has disappeared into the copper, we 
shall have to experiment with the residuum. Let 
a glass jar J, Fig. 9, be filled with the gas. How ? A 
two-foot length of }" gas pipe 2 (Fig. 10), is charged 



FIG. 9. 



FIG. 10. 




with copper gauze, and placed in a charcoal fur- 
nace 4- Rubber tube 5 leads to bottle 6 through a 
two-hole stopper ; so that the funnel stem 7 may pass 
through second hole. If water be poured into the 
funnel the air will be driven through the heated 
copper, and the -J- residuum will pass through 1 
into the inverted and water-filled jar / whose open 
end is supported under water by metal blocks in 
the basin B. We will now do a little figuring. We 



12 CHEMISTRY SIMPLIFIED. 

found above that 1 gram of copper can absorb 0.25 
gram of air. One litre equals 1000 c.c. of air and 
weighs 1.2932 gram, hence -J- of this weight is 0.258, 
that is one single gram of copper is sufficient to 
take the absorbable gas from one litre or one quart 
of air. 50 grams of copper will furnish (50x4)/5 
equal 40 litres of the gas we desire. But for our 
experiment, that is to fill the jar, we will not need 
more than one or at the most two litres supposing 
that the whole of the water has been displaced in J 
so that the bubbles will come on the outside. We 
remove first the tube 1, then the supporting blocks 
and push a flat glass plate under the water, and 
press it with the hand against the jar rim, lift the 
jar out and stand it bottom down on the table as in 
Fig. 9. A mouse having been trapped, we drop the 
animal from the trap into the jar and replace the 
glass cover plate. At once the mouse shows dis- 
tress, tumbles into a heap, and after a few spasmodic 
kicks lies quiet and is dead. Hence we draw the con- 
clusion that the part of the air which is absorbed 
by the copper, is the part also which sustains animal 
life. If we introduce a burning taper into the jar 
it will become at once extinguished, and hence it 
follows with some considerable probability that 
breathing, burning and scale forming of copper are 
similar processes, being in fact, fundamentally, the 
same phenomenon. 

It will be necessary, for clearness and conciseness 
of expression, to distinguish from now on these two 
parts of the air by separate names. Properly we 



NATURE OF AIR AS A MIXTURE OF GASES. 13 

should say in English life-air and death-air; 
instead Greek words are chosen by scientists. Life 
air equals ozone ; death air equals azote. The root 
of both words is Zoe equals life (zoology equals the 
science of living things). Ozone equals intense life ; 
azote equals no life. German chemists made and 
use the term, stickstoff equal to suffocating stuff; the 
French hold on to azote, English and Americans 
now use the word nitrogen which equals niter-pro- 
ducer 

Weight of one c.c. of nitrogen equals 0.001256 
gram (Regnault). 

Weight of one c.c. of air equals 0.001293 gram. 

Hence it follows that ozone must be heavier than 
air. The weight of ozone follows by calculation. 

We reduce azote to terms of air by dividing the 
weight of air into that of azote, 0.001256/0.001293 
equals 0.97137 which equals the specific weight of 
azote or its specific gravity, then we have 

4 /<A 9713 + ! =1; x =(1-0. 777)5 = 1.1 145, 
o o 

the specific gravity of ozone, and 1.1145 X 1 -293 = 
1.441, the weight of 1000 c.c. of ozone, and 0.00144, 
the weight of one c.c. of ozone. 

Among the substances more or less familiar to 
every one of us is sulfur, which I show you now as 
crystal and massive as a broken lump. Light yel- 
low color and translucency distinguish it from other 
bodies. If washed in water first, it yields no taste, 
it is insoluble in water. Against heat it is quite 



14 



CHEMISTRY SIMPLIFIED. 



susceptible. I place some of it upon this porcelain 
crucible lid and put the flame underneath. We see 
it melt quickly into a dark red-brown liquid, and 
then vaporize. Shortly after a blue flame appears 
and a strong, pungent odor permeates the air. The 
sulfur disappears slowly. Queries. 1. Is this phe- 
nomenon similar to that of the scale forming of 
copper, to the burning of the taper, to the breath- 
ing? Has either the ozone or the azote part in the 
disappearance? Let the flask 1 be filled with air 
and a few c.c. of water as shown in Fig. 11. Take 




a strong iron wire 2, hammer it flat at one end and 
rivet it to a small iron dish 3. Put sulfur into the 
dish, heat the latter over a flame until the blue 
flame is strong, then lower the dish into the flask 
until the plate covers the mouth of the flask. The 
sulfur keeps on burning. Soon a white cloud ob- 
scures the flame. After some minutes we remove 
the spoon and notice that it begins to burn when it 
reaches the outer air. (Why? Because it again 
finds the ozone, which had become used up in the 



NATURE OF AIR AS A MIXTURE OF GASES. 15 

flask.) We now shake the water and the gases 
together in the flask and pour out the water. It is 
somewhat turbid or milky ; after filtering it is clear, 
it has a sour taste and changes the purplish color of 
litmus to bright onion red. Litmus is obtained by 
extracting a lichen named by botanists Roccella 
tindoria. The collected lichen is allowed to fer- 
ment in heaps, is then torn by a machine and al- 
lowed to stand with water, which assumes a deep 
purplish color; is used as a dye stuff under the 
name of orseille. Now vinegar has the same action, 
i. e., a sour taste and turns litmus red. Vinegar 
(from French viu-aigre equal wine sour) arises when 
the sugary juice of grape or any other fruit, is al- 
lowed to stand in a warm place. 

Wine results in a cool place. (Details will be 
given later.) The Latin name for vinegar is aridum, 
hence it came that later on all sour substances were 
and are called acids in English, French, Spanish, 
Italian; but in German the word satire = a sour- 
ness, and in Swedish syra, only differing in the 
vowel. 

When Lavoisier, in 1781, had observed the above 
phenomena, he proposed the name oxyg^ne in 
French, oxygen in English for what we have named 
ozone or life-air. The word oxygen is derived from 
the two Greek words oxus = sour, sharp, biting and 
genomein = to produce, to generate. This name 
we shall use in the future. 

Definition: The combination of oxygen with a 
metal or non-metal is hereafter to be designated an 



16 CHEMISTRY SIMPLIFIED. 

oxyd oxid oxide. The first spelling is the gram- 
matically more correct, but the last spelling oxide 
is at present mostly used by English and American 
chemists. I myself use oxyd the derivation is 
from oxydatus = oxydized. 

Hence copper scale is now copper oxyd, the pene- 
trating gas from burning sulfur is sulfur oxyd. 

General deductions. Air being a compound of 
azote -f oxygen and copper oxyd of copper -f- oxy- 
gen, they both seem to be representatives of the 
same type of bodies i. e., compounds. Whether all 
compounds are of one kind or not, we cannot, at 
this stage demonstrate. The term compound re- 
quires single, or simple as opposite. We will define 
as simple bodies or elements all those bodies which 
can be brought back from their compounds to their 
first condition i. e., with all their previous physical 
properties. This definition is raised in our minds 
by the behavior of copper oxyd when heated in a 
closed tube with splinters of charcoal. At a red 
heat, the scale of copper oxyd becomes yellowish- 
pinkish. On cooling a spongy mass of the metal is 
seen, and the metal possesses all previous proper- 
ties. Hence copper is a simple body or element. 
The question arises : Are all our well-known metals 
elements? Experiment on the same line as that 
with the copper, answers the query in the affirma- 
tive, though there will be found experimental diffi- 
culties with some. When zinc has been burnt in 
air, at high heat, into white zincoxyd, and when we 
heat this oxyd with charcoal, we will get no satis- 



NATURE OF AIR AS A MIXTURE OF GASES. 17 

faction because the zinc only gives up its oxygen to 
the coal at a white heat which the glass tube cannot 
stand ; and moreover, at this high temperature zinc 
itself is a vapor. Special arrangements must be 
made in this case to catch the zinc vapors, which 
will first condense to a liquid and the latter will 
solidify into metal with all previous properties. 
Though we know as yet nothing of the nature of 
charcoal, we must surmise that it contains a body 
which has a stronger attraction or affinity for oxy- 
gen, at high heat, than the metal. Owing to this 
we designate charcoal as an deoxydizing substance, 
and the process itself we call deoxydation. 

Copperoxyd -f- charcoal -f- red heat = deoxyda- 
tion. That the charcoal forms a new oxyd during 
this action we surmise at once. Because we see no 
deposit of any kind on the charcoal or on the tube, 
we infer that this new oxyd is a gas at the ordinary 
temperature of the air. By using only the first let- 
ters as symbols, we can represent the processes thus : 

Cu -f + red heat CuO oxydation. 

CuO + C (charcoal) + red heat = Cu + CO = de- 
oxydation. 

Sulfur oxyd can be decomposed by passing it in 
a glass tube over heated charcoal. Sulfur will de- 
posit in the tube ; hence sulfur is an element, ac- 
cording to our definition. Yet sulfur is not at all 
like the metals. As mentioned above, it is trans- 
parent and very brittle, melts at a very low heat 
and becomes a vapor at 250 C. Hence we at once 
make two classes of elements: metallic elements: 
copper, tin, lead, iron, and so forth ; non-metallic 
elements : sulfur, oxygen, azote, etc. 
2 



CHAPTER II. 

THE NATURE OF WATER. 

To us who are dwelling on the shores of a great 
lake, or to the inhabitants of the seashore, the idea 
must early present itself that water must be of much 
importance in the household of our planet, but even 
to him, the savage, or half savage, who uses water 
merely to quench his thirst, water must be an ob- 
ject of veneration ; and the inquisitiveness of the 
human mind must bring forth even in him a desire 
to learn more about it. The ancient thinkers, with- 
out experiments, said water is one of the primary, 
elementary things, and together with air, fire and 
earth, constitutes the great Quartette out of which 
comes the harmony or disharmony of all things. 
Man's body is made of earth and water, his soul of 
air and fire, thus combining within himself the four- 
primary things. The elementary nature of water 
was undoubted up to the end of the 18th century. 
The traveler becomes acquainted with good water 
and bad water ; water which has a bitter taste, an 
astringent taste, a salt} 7 taste, a nauseous taste. He 
learns to distinguish between Spring water, River 
water, Swamp water, Sea water. It was early ob- 
served that water combines with fire, and thus pro- 
duces the scalding steam which would lift the cover 
off a pot. 

(18) 



THE NATURE OF WATER. 19 

Water becomes a solid, transparent block under 
the influence and sway of chilling Boreas, the 
Xorthwind. To this splendid and fleeting thing 
the Greeks gave the name Krystallos, sometimes 
Kryos, and thus became the founders of Orystal- 
lography, because when they found the beautiful 
transparent Rockcrystal, which we now call Quartz, 
they considered it as a sort of permanent ice, and 
also called it Krystallos. Thus the name was ap- 
plied much later to all bodies which exhibit geo- 
metrical outlines. Remember this connection be- 
tween ice and crystal. More wonderful seemed the 
snow, and it took much hard thinking and much 
controversy until snow was admitted to be merely 
frozen rain. You throw your snowballs and skate 
over the ice and never once think anything at all, 
except that it is a part of Winter's fun, and yet for 
a hundred years men have been studying the form 
of snow-flakes, and each one found something new. 

Physical properties of water. Reference is here 
made only to so-called distilled water, that is, water 
which has been in the form of steam at least twice, 
and which has only been kept in porcelain crocks. 
All other water is impure in differing degrees. 

Water is a liquid between the temperature of 
and 100 C. Below C. it is solid ice brittle, 
and yet to some extent plastic, that is, capable of 
deformation under strong, slow pressure. (Bending 
of glaciers when plowing over undulating rocks.) 
Ice is colorless in small pieces, in great masses it 
shows a green or sometimes a deep blue color. 



20 CHEMISTRY SIMPLIFIED. 

Water is without taste (distilled, water) ; hence 
not pleasant to the palate. It is without color when 
seen in a bottle, flask or jar; but when looking 
through a long column it becomes more and more 
blue, that is, all but the blue part of the sunlight 
becomes absorbed. The finest effect is seen off the 
Savoy shore on the Lake of Geneva (Switzerland), 
where the rocks fall abruptly into the water to a 
depth of 980 feet. The ocean looks blue-black, but 
this is not water which can be compared to distilled 
water, whereas the water of the Geneva Lake is re- 
markably pure, having a steady and strong outflow 
in the Rhone River. 

A litre of water at -f- 4 C. weighs sensibly more 
than at C., hence ice will float on water. If, 
however, the temperature of water is raised by heat- 
ing it will loose in density and soon the block of ice 
will sink to the bottom. 

Water dissolves all solids, some very slightly, 
others in large quantities. Note this very import- 
ant property. The purer the water the more ener- 
getic is the solving action. It attacks and slowly 
dissolves ordinary glass, but porcelain very much 
less, and platinum and gold still less. 

Water absorbs all gases, some to a large extent, 
others to a very small extent. Hence the purest 
distilled water will not remain so but for a very 
short time. For absorption begins as soon as the 
stopper is removed, in fact has already set in before, 
unless the vessel had been full up to the stopper. 
As a rule all absorbed gases can be expelled by pro- 
longed boiling. 



THE NATURE OF WATER. 21 

Chemistry. The first query will be : Is water a 
simple, elementary body or is it a compound? 
Having observed that air can be broken up by 
metals and by sulfur at a red heat, we shall be con- 
sistent if we subject water to the same treatment. 
We start, therefore, with the assumption that water 
is not a simple body. The experiment will presum- 
ably proceed under proper conditions if a hard glass 
tube T, Fig. 12, with perforated stoppers be placed 
horizontally with a boat holding finely granulated 
zinc or iron filings in the middle of the tube. A 
glass syphon 5 reaching into the beaker is con- 

FIG. 12. 




nected by rubber 1 with stopper 2 while a clamp 3 
permits a stop to the flow of water as well as a regu- 
lation of the rate of inflow. A delivery tube 5 leads 
just under the surface of the water in basin 6 and a 
test-tube 7 filled with water stands ready to receive 
any gases which might result from the action. 

Let the flame from the burner B be now put 
under the boat and water admitted drop by drop at 
2 so that a small pool forms behind the cork. As 
the heat extends along the glass tube the water will 



22 CHEMISTRY SIMPLIFIED. 

begin to pass into steam and the steam will push 
out the air. When the latter is all out the steam 
will condense in tube 5 and of a sudden water will 
rush from 5 into T, will run to the red hot place at 
the boat and the T cracks. The apparatus is not 
up to the requirements. Why should not an iron 
gas pipe do in place of a glass tube ? Since we are 
studying the action of steam upon the metals a 
metallic tube can do no harm, and any sudden in- 
rush of water cannot injure the tube. Let therefore 
a gas-pipe of similar dimensions be- substituted. A 
further advantage of such a tube will be that a 
higher degree of heat can be applied say by means 
of a gas blow-pipe. 

1. Action on bright iron turnings. 

A gas is generated which we collect in the test- 
tube. It possesses an unpleasant odor and burns 
with a faintly colored flame. The chips have lost 
their brightness, they have become gray-black, and 
when struck with the hammer a brittle scale comes 
off. The scale is attracted by the magnet the same 
as the chips themselves. Deduction: This scale, re- 
sembling in every respect ordinary blacksmith's 
hammer scale, which is made by heating iron in 
air, like the other metal scales, leads us to conclude 
that water must contain oxygen. 

2. Action upon granulated zinc. 

Gas of the same character but odor less pro- 
nounced. The zinc is either converted wholly or 



THE NATURE OF WATER. 23 

partly into white or grayish-white powder, or into a 
shining lustrous crust, which under the microscope 
shows six-sided prisms and pyramids. Character 
same as zinc oxyd obtained in air. 

3. Action upon copper turnings. 

Gas does not appear until tube has become yellow 
hot, and comes sparingly. Has no pronounced 
odor, but burns. The copper has become bright 
red from the brittle copper oxyd. 

The three trials demonstrate that water is a com- 
pound, not an element ; and further, that it is an 
oxyd, in which oxygen is united with the other 
body, the latter appearing in the free state as a 
light, odoriferous gas. 

Reverse proof . Collect the gas in a large bottle (use 
arrangement for collecting as in the case of azote). 
Stand the bottle 1 (Fig. 13) containing the gas up- 
right. Its stopper holds the long funnel tube #, 
with rubber connection and clamp 3 and the deliv- 
ery tube 4 which connects with the drying tube 
the latter being filled in the bulb with absorbent 
cotton and in the cylinder with burnt lime. Tube 
6 is drawn out into a fine point (not too fine), and 
the glass cylinder, open at both ends, is held by a 
clamp and stand as shown in figure. If now water 
be run from the funnel into bottle, the water will 
drive the gas through, and if a burning taper 
be held to the tip of 6 two things can happen: 
either a steady flame 8 or an explosion which may 
shatter the tubes. (1 volume of the gas mixed with 



24 



CHEMISTRY SIMPLIFIED. 



2^ volumes of air explodes violently.) To avoid 
explosion, let the gas go through the tube for a 
while until the water has risen in the bottle about 
one inch and then only apply match or taper. 
The flame is first colorless, but soon burns of an 
orange-yellow color. Why ? Because the glass, at 
a red heat, gives particles to the flame. Prove this 

FIG. 13. 




by placing a nozzle of silver, platinum or gold over 
the tube. The flame will then be invisible or 
nearly so, faintly purplish. 

But the important part is that immediately when 
the flame appears the glass cylinder 7 becomes 
clouded and soon large drops of liquid condense 
upon the glass which will even collect and run from 
the lower edge of the tube. We find all the physi- 



THE NATURE OF WATER. 25 

cal properties of distilled water in this liquid : Equal 
weight per equal volume ; absence of taste and 
smell ; equal resistance to passage of light ; change 
into solid at C.; change into vapor at 100 C.; 
very high resistance to the passage of the electric 
current ; equal capillarity, by which is meant that 
both liquids rise in a very narrow or hair tube 
equally high above the outer level. Therefore, it 
is proper to apply the name hydrogen to this gas. 
Hydor = water, genomein = to produce: -the body 
which produces water. It follows that water must 
be hydrogen, oxyd. 

ELECTROLYSIS. 

Next to heat we find electricity as the most in- 
tense force, or probably both are only different 
manifestations of the same force, since heat can be 
made to generate electric current, and an electric 
current converts itself into heat under proper con- 
ditions. We will not investigate the generation of 
a current here and simply assume it as given ; you 
will get the explanation in physics. We simply 
accept the fact that if I fasten this wire to the one 
binding post on the table and this other wire to the 
second post, and if the wire ends be brought in con- 
tact there is now flowing a current from one post to 
the other. If I break the contact a minute blue 
spark is the visible proof that a current was passing, 
but does not pass now. Why? The air space 
between the wires does not carry the current, air 
being a non-conductor. 



26 CHEMISTRY SIMPLIFIED. 

In Fig. 14 a beaker glass is filled with distilled 
water ; after bending the wires at right angles I 
sink the vertical portions into the water. The 
needle on this galvanometer does not move, hence 
it follows that the water between the two wires is as 
much a non-conductor as air ; of course I speak 
relatively ; it is a question of tension or pressure, 
for the current passes from cloud to earth in a 

FIG. 14. 




thunder-storm, and to say that air and pure water 
are bad conductors, will be a better expression than 
non-conductors. 

If we substitute this Houghton- spring water for 
the distilled water, we see the needle move, and 
hence deduce that the earthy materials which are 
dissolved in the water cause the better conductivity. 
An addition of salt to the water proves the correct- 
ness of the deduction. We see not only the diversion 
of the needle, but we see gas bubbles rise from the 
wires. The liquid conductor of the current is called 
electrolyte. The wires dipping into the latter are 
known as electrodes. The wire leading to the posi- 
tive pole -f is the anode, the one leading to the 
negative pole --is the cathode. They are always 
designated by the -f- and signs. 



THE NATURE OF WATER. 



27 



If we arrange the apparatus as shown in Fig. 15, 
where 2 means a test-tube, filled with the electrolyte, 
and where the electrodes are spread, having strips 
of platinum sheet soldered to themselves, we will 
perceive at once the current going through that 
much more gas arises from the cathode than from 
the anode. On applying a match to the gas, after 
the test-tube has been lifted out, there is a strong 

FIG. 15. 




explosive sound ; the tube may be splintered. AVe 
call the gas fulminating (lightning like). What is 
the nature of this gas? That two different gases 
are produced we find indicated in the larger vol- 
ume of gas coming from one of the electrodes ; and 
thus we are led to collect the two portions separately. 
Let us take two large test-tubes B, B' (Fig. 16) and 
blow into the closed end two narrow tubes 1, 2 be- 
fore the blow-pipe. This requires some skill ac- 
quired by practice. To acquire such skill is very 
useful to any one who wishes to become a chemist ; 
for glass-blowers are not always in the neighborhood. 



28 



CHEMISTRY SIMPLIFIED. 



However, in this case, we can avoid glass-blowing 
altogether by cutting off the closed end of the tubes 
by means of a file and a red-hot glass or iron rod. In 



FIG. 16. 




B 




B 



Fig. 17 you see the tube before and after cutting, 
and only a perforated stopper is needed with a nar- 
row glass tube t t to which the short rubber tube with 
spring or screw clamp and a second bit of glass tube 
are attached. Calibrate now the tubes roughly into 
cubic centimeters. Fill the tubes with the elec- 
trolyte, hold them by a suitable stand in the basin 
A (Fig. 16), and insert from below the electrodes 

H . The current being turned on it soon becomes 

evident that the gas volume in B' is much larger 
than in J5, that in fact the two volumes are as two 



THE NATURE OF WATER. 



29 



to one. But in E' we have the negative pole, the 
cathode ; in B, the positive pole, the anode. When 
B' is filled with gas to the electrode we stop the cur- 
rent ; draw out the electrode, shove a small cup 
under the tube, lift the latter and bring it into a 



B 




B 




wide cylinder (a pail will answer, in default). Now 
if we press the tube B' down into the water until 
there be a difference, H t Fig. 18, between the outer 
and the inner levels, then the gas will be under a 
pressure equal to the weight of a column of water 
of the height H, and if the clamp C be cautiously 
opened the gas must issue at P. We notice first the 
absence of any smell ; the absence of acidity, and 
then apply a taper or match. A flame appears at 
the point. A cold porcelain dish held in the flame 
covers itself with moisture. In fact the gas acts 
exactly like the Hydrogen which we obtained pre- 
viously, except that it has no odor. The former gas 
must have held some odoriferous body admixed. 
(Supposition which must be verified at a future 



30 



CHEMISTRY SIMPLIFIED. 



stage. As careful investigators we must heed every 
difference of action. In this instance we shall find 
that zinc and iron contain small quantities of cer- 




tain other elements, which combine with hydrogen, 
producing strongly smelling gases.) 

We proceed to operate now with tube B (Fig. 16) 
by transference to the pail or large beaker. The 
gas has neither odor nor taste. On bringing a match 
over the jet no flame, but the coal of the match 
burns with intense light. . A piece of red-hot copper 



THE NATURE OF WATER. 31 

or iron wire held into the current, burns with strong 
light into a scale which has all the properties of 
copper oxyd, iron oxyd. 

The gas shows therefore in an intensified form the 
behavior of air. It must be oxygen. That it is only 
oxygen we can prove by heating a given volume of 
iron or copper filings over mercury. On cooling 
the mercury will fill the entire tube ; all the gas has 
been absorbed. 

Deductions. 1. Water is a chemical compound of 
the two simple bodies, hydrogen and oxygen. It 
must be a chemical compound because water is a body 
showing altogether different properties from those of 
a mere mixture of the gases as we have it in ful- 
minating gas. 

2. Elements combine according to simple ratio of 
volumes, as water is composed by volume of 2 hy- 
drogen, 1 oxygen. If the letters H and stand for 
the two elements then the symbol 

H 2 water = dihydrogen monoxyd 

expresses this relation. 

Inverse proof of this proposition. 

Let E (Fig. 19) be a graduated or calibrated glass 
tube, near the closed end of which are fused into the 
glass 2 platinum wires (-f- ). Such a tube is known 
as eudiometer = splendid or perfect measure. Let it 
be furnished with a jacket J made of a wide glass tube 
(lamp chimney); a cork C holds it against the eudio- 
meter. A narrow glass tube leads from the boiling 
flask F through the cork into the jacket ; th is a 



32 



CHEMISTRY SIMPLIFIED. 



thermometer. Introduce about 10 c.c. of fulminat- 
ing gas into the eudiometer, the mercury standing 
as in the figure. If now the water in F be kept 
hard boiling until the thermometer shows 98 to 
100 C., the volume of the gas will have increased 
considerably. Let us say it reads 11.0 c.c. Connect 
the platinum wires with poles of an induction coil, 
also known as Rhumkorf coil from the inventors 



FIG. 19. 




name ; a spark will pass between the platinum wire 
ends in the eudiometer with a considerable shock. 
(Hold the eudiometer with the hand to prevent its 
being lifted clear of the mercury in P.) On read- 
ing now the volume, we find it shrunk to 7.3 c.c. 
A contraction has taken place of 3.7 c.c. or one-third 
of the original volume. Stop the steam, draw off 
condensed water, and let come to the temperature of 
the room. The mercury will rise steadily until it 



THE NATURE OF WATER. 33 

fills the entire tube, except a bubble of water at the 
very apex. 

Explanation. The high temperature of the spark 
causes the union of the hydrogen with the oxygen, 
and at the temperature of 100 C. water is in the 
form of steam. The steam occupies two-thirds the 
space which was occupied by the mixture of gases. 
The union therefore caused the mass particles of the 
gases to approach each other at a fixed distance, so 
that three occupy now the space of two. 2 vols. H 
-f- 1 vol. give 2 vols. steam. As the temperature 
sinks the steam becomes water and thus the mer- 
cury can fill the tube because the quantity of steam 
expressed by 7.3 c.c. corresponds only to a few mil- 
ligrams of water, for 1 c.c. of steam at 100 C. weighs 
0.0005896 gram, hence 7.3 c.c. = 0.0043 or 4.3 mil- 
ligrams, which in the form of a drop of water is 
barely distinguishable with the naked eye. The 
11 c.c. of gas must have possessed the same weight 
of 4.3 milligrams. 

Law. Whenever gaseous elements unite in the 
ratio of 2 : 1 a contraction of one-third ensues. 

Comparing the weights of the 3 gasiform ele- 
ments which we have now discovered and studied 
to some extent, we find that hydrogen : oxygen : 
azote = 1 : 16 : 14. Oxygen is 16 times heavier in 
equal volume than hydrogen, and azote 14 times 
heavier. Therefore H 2 represents 2 + 16 = 18 
weight units and if the smallest mass of each of these 
bodies, still capable of receiving a chemical impetus and 
acquiring thereby an active force or momentum, be de- 
3 



34 CHEMISTRY SIMPLIFIED. 

signaled as atom, then the figures 1, 16, 14 may be 
designated atomic weights, because the ratio will be 
the same as long as the volume is the same, for the 
largest as well as the smallest units. 

Hydrogen peroxyd, H 2 2 . 

Under certain conditions H and can form a 
higher oxyd or peroxyd (per meaning beyond). This 
is a body of unstable nature ; it falls to pieces easily 
but possesses extraordinary activity as an oxydizing 
agent. We shall study the mode of its preparation 
later as well as its application. 



CHAPTER III. 

GREEN VITRIOL OR COPPERAS. 

UNDER the name copperas, which is the corrupted 
form of the French couperose, and the latter even 
a corruption of the Latin cupriaerosa, which 
means the "Rose of Cyprus," a substance of most 
marked properties has been known from time im- 
memorial. We see it as bluish-green fragments and 
also in the form of large crystals. The symmetry 
of the faces can be reduced to the monoclinic sys- 
tem. Thin pieces are quite transparent and show 
very little color ; because the depth of color is de- 
termined by the partial absorption of certain por- 
tions of sun light. The thicker pieces absorb more 
light in the transit of the latter and therefore have 
a deeper color. The substance is very brittle ; it can 
be crunched between the fingers. Has a strongly as- 
tringent, bitter-sour taste, and is quite soluble in 
cold water, but very much more soluble in boiling 
water. The solution is not clear, but murky from 
a brownish-yellow, suspended substance. By filter- 
ing through paper the solution becomes clear. If 
such a .clear solution be left standing exposed to the 
air, one notices the rapid forming of a yellow film 
on the exposed surface. The film becomes thicker 
and in time the liquid turns into a yellow brown, 
(35) 



36 CHEMISTRY SIMPLIFIED. 

mud-like fluid. Query ? Has the oxygen of the air 
anything to do with this change, or the azote ? This 
is easily settled by bringing some of the fresh, clear 
solution into a tube filled with azote and closing the 
tube tight. No change occurs. Another portion in 
a tube filled with oxygen, the film appears. Oxygen 
does the work. If the solution of copperas comes 
together with oak bark, the latter turns speedily 
black (in reality deeply blue-purple). It also turns 
leather black because the latter forms when raw 
hide is allowed to soak in water and ground oak 
or hemlock bark. We can extract the leather- 
forming substance from the bark by means of water 
and this solution turns black with copperas. Thus 
came into existence our black writing ink, already 
known to the ancient Egyptians. When the extract 
of bark is evaporated on a water-bath, a faint yellow- 
ish scale, very light and fluffy, remains : tannin 
(from tan). Copperas -f~ water + tannin == ink ; 
mucilage is added to give the ink a better body. 

The Germans use the word vitriol instead of cop- 
peras. This name was first used by Pliny who 
lived 1900 years ago. He describes the substance 
as " vitriolus quasi vitrum" Vitrum is Latin for 
glass, the crystals resembling green glass were yet 
easily soluble in water, while glass is not soluble. 
Glass is fairly hard, this substance not, hence vit 
riolus, a kind of glass, like glass in some ways. We 
shall use the word vitriol as being better expressive 
of the substance. 



GREEN VITRIOL OR COPPERAS. 



CHEMICAL INVESTIGATION OF GREEN VITRIOL. 



37 



Let a hard glass tube (J to \" internal diameter and 
6 to 8 inches long) (Fig. 20) be closed at one end over 
the gas blow-pipe. Hold the tube in nearly hori- 
zontal position or rather lower at the open end, the 



FIG. 20. 



T A 


1 


(=-* 




c 


B 


-> L_ 

s 


I 

S' 

I 



closed end being charged with several small pieces 
of vitriol. Let the tube be supported at S, because 
it has a tendency to sag when the end comes to a red 
heat. It stands to reason that the tube may be 
laid upon a couple of bricks for support. Let heat 
be applied slowly with the burner B to the closed 
end, and we will be enabled to make the following 
observations : 1. A plentiful condensation of a 
liquid in the cool part of the tube. This liquid 
will appear very mobile, little or no taste and by 
applying electrolysis will give H + ; its identity 
with water is fixed. 2. The vitriol meanwhile, is 
partly melting, raising blisters and turning into a 
white chalky mass. 

Deduction 1 : The loss of water causes the vitriol 
to become white opaque. We raise the temperature 
to a low redness : A strongly smelling gas appears re- 



38 



CHEMISTRY SIMPLIFIED. 



calling the smell of burning sulfur, that is the oxyd 
of sulfur S n O m . We cause it to act on indigo and lit- 
mus solutions, the former becomes bleached, the lat- 
ter turns red ; probability strong that vitriol contains 
sulfur oxyd though not certain yet. But remem- 
bering that copper oxyd is decomposed by charcoal 
at red heat, we may attempt the decomposition of 
this suppositious oxyd in the same way and with- 
out much of an outlay in apparatus. Let some 




vitriol be heated in a porcelain crucible until it 
has become white, that is, until the greater part of 
the water has been removed, then fill it into a tube 
exactly the same as before, that is, at the closed end 
a, Fig. 21. Let some splinters of charcoal be heated 
in a covered crucible at full red heat, and when cooled 
down introduce them into the tube at b ; stopper the 
tube with cork and gas evolving tube t, the latter 
leading into basin B filled with water. The water 
filled test-tube T is held ready to be shoved over 
the end of t, when it may be assumed that the air 
has been quite driven from the apparatus by the 



GREEN VITRIOL OR COPPERAS. 39 

evolved gases. The closed end a is first brought to 
redness, then the charcoal at b is brought to dull 
redness, or any other degree of temperature we may 
find advisable. If the gas be decomposable exactly 
as copper oxyd is decomposed, we must get 

S n O m + 9 C = S n + m CO + (9 m) C., 

but since sulfur is a non-metal, it is quite probable 
that compounds of S and C are generated, for 
which we must look out. The glass tube is best 
supported by two bricks, -P, P', stood up on edge. 
In order to facilitate the deposition of sulfur we 
protect the part of the tube beyond the charcoal 
with a diaphragm or screen d. The latter can be a 
slotted piece of sheet-iron or a piece of asbestus 
board. As soon as the charcoal becomes red at one 
spot, we notice a film forming before the diaphragm, 
which increases in bulk, forming yellow and yellow- 
brown drops. The water in the basin becomes tur- 
bid, milky, and a gas of peculiar smell collects in 
the test-tube. What causes the milkiness ? What is 
the peculiar smell due to ? . These questions we shall 
not attempt to answer at this juncture, but place 
them on the calendar for future study and explana- 
tion. We let the tube cool down, cut it with file and 
hot glass rod at the diaphragm, and subject the yellow 
film to two tests, (a) We scratch out a portion of the 
unknown yellow substance, place it upon a piece of 
bright silver foil, and heat it over a flame, until the 
foil is barely red hot. When cold a black spot or 
possibly a hole will appear, where the unknown 



40 CHEMISTRY SIMPLIFIED. 

substance was placed, the silver has formed a black 
compound and this is characteristic for sulfur, (b) 
We hold the tube inclined to get draught and heat 
the film in the flame ; we get the pungent odor of 
burning sulfur. No doubt can remain, vitriol con- 
tains sulphur oxyd, or at any rate we can say that 
this gas is one of the products when vitriol is 
broken up by heat. 

Now let us return to the original experiment 
which we left in order to prove the sulfur oxyd. 
We apply now a very hot flame (best from a Bunsen 
gas blow-pipe) to the vitriol. White clouds appear 
in the tube and roll out of the latter ; the substance of 
this fume is evidently heavier than air. The action 
of it upon the mucous membrane is energetic, for a 
suffocating sensation 1 is caused by inhaling it. It 
causes the muscles of the larynx to contract vehe- 
mently. At the same time, with the appearance of 
the fumes, we notice a thick liquid condensing at a 
little distance from the heated end of the tube. We 
let the latter cool down and cut it off just at the 
liquid ring ; as the two pieces come apart another 
installment of white fume appears. Why? We 
apply litmus-paper to the liquid ; it turns intensely 
red, but soon after turns brown, and finally the 
rim gets black ; the paper has been charred. De- 
duction : The liquid possesses qualities of an ex- 
traordinary nature. The great experimenter who 
discovered it in the 10th century, the Moor Geber 
in Spain, gave it an Arabic name which was trans- 
lated into Latin : oleum vitrioli the oil of vitriol, 



GREEN VITRIOL OR COPPERAS. 



41 



owing to its sluggishness in flowing like a thick olive 
oil, and because it produced a lubricating of the 
skin when rubbed between the fingers. In order to 
study the substance, we must design an apparatus 
which will allow the treatment of a considerable 
quantity of the vitriol, say one pound. Since we 
noticed that the glass became quite soft and even 
collapsed when exposed to the high temperature of 
the blow-pipe, we must look out for a material 
which will remain solid as well as rigid at such a 
temperature. Fire-clay is such a material. Its 

FIG. 22. 




plasticity when mixed with water makes it capable 
of being moulded into any desired form. When 
carefully dried and then equally carefully baked, 
it becomes hard, fire-resisting, and fairly gas-tight. 

In Fig. 22 we see the section of a fire clay retort 
inside of a fire-brick lined furnace, which is heated 
by a gasoline flame F. Before filling the vitriol 
into the retort, we heat it in an open dish or large 
crucible until all the water is driven out, and until 
it has turned a light brick red, that is, at a low red 
heat, since we only care for the white, cloudy fumes 



42 CHEMISTRY SIMPLIFIED. 

and not for the sulfur oxyd. Then we fill the ma- 
terial V through the tubulature at S and fasten the 
stopper or plug by means of pasty fire-clay. Over 
the neck of the retort N, we pass the neck of the 
large glass flask R loosely, to furnish exit for the 
gases. The flask we bed into a mixture of salt and 
broken ice (freezing mixture) contained in a basin 1 
and over the upper side of the flask we spread a 
muslin bag I' filled with the same mixture. Why ? 
In order to expose a maximum of cold surface to the 
fumes, having seen in the preliminary experiment 
that the fumes do not condense at the ordinary tem- 
perature. The lid of the furnace having been put 
in place, we light the flame under strong air pressure 
and soon the retort will show cherry redness on the 
outside. But since the fire-clay wall of the retort is 
but a poor transmitter of heat, some further time 
must elapse until the material Fgets to that temper- 
ature. Then we see the white fumes pouring into the 
flask, falling like a foaming cataract to the bottom 
and also issuing at the neck of the flask. Hence the 
apparatus should stand under a good up draft or 
alongside a good down draft. The heat will be mod- 
erated or increased according to the volume of white 
vapor issuing from the neck N. If no more fume 
comes say after two hours even at a yellow heat 
of the retort, we stop the operation. We remove the 
basin I and the bag I' and wipe the outside of the 
flask dry. Three facts are observable : A brownish 
thick liquid about 50 c.c. ; snow-like crystals of needle 
shape all over the flask ; and a dense fume still filling 



GREEN VITRIOL OR COPPERAS. 43 

the flask. We pour the liquid into a large test-tube, 
or into a smaller flask. During this operation quan- 
tities of the white fumes arise suffocatingly from the 
liquid, wherever the air touches it. Query ? Which 
constituent of the air causes this action? Azote, 
oxygen or the water vapor ? By experimental elim- 
ination we fix the action upon the water vapor = 
moisture, of the air. Withaut moisture no fumes. 
Hence it follows that the roasted vitriol must still 
contain some water, or else we could not see the 
fumes inside the glass tube in our first experiment. 

Two immediate investigations must now be un- 
dertaken ; we must first try to get at the inwardness 
of the crystallized substance, and secondly, of the 
liquid substance. 

a. Investigation of the oil of vitriol, the liquid 
substance. If put upon the skin, a drop will raise a 
blister and actually burn a hole into the flesh, de- 
stroying the tissue thoroughly. 

Brought together with a drop of water a hissing 
sound is caused. If water be splashed or poured 
into a larger quantity of the oil, so much steam is 
generated by the evolution of heat, that the liquid 
is thrown violently from the vessel and has often 
injured the careless operator. Paper is charred 
into a slimy, black substance by the oil. White 
sugar arid starch are changed into the same black 
substance. 

The oil smells strongly of the sulfur oxyd gas, 
and when heated emits white fumes, until at the 
end a liquid results, nearly colorless, which does 



44 



CHEMISTRY SIMPLIFIED. 



not fume at the air, and does not smell of sulfur 
oxyd. This colorless liquid boils at 326 C. (a very 
high temperature), giving likewise dense white 
fumes to the air, when boiling, which condense into 
a colorless heavy liquid, thus differing from the white 
fumes of the oil, which condense into a snowy solid. 
With an arrangement as in Fig. 23, we can prove 

FIG. 23. 




these points. In the small retort on the left of the 
figure we place some 10 c.c. of the oil of vitriol, 
using a long-stemmed funnel, so that the neck shall 
not be moistened with the liquid. 

At 3 we have a thermometer not reaching into 
the liquid ; fasten it into the tubulature with asbestus 
thread. The retort is held by a clamp from stand 
4. At 5 we have a U-tube connected by a narrow 
tube with the neck of the retort through a cork. The 
U-tube is also fitted with perforated stoppers and 
stands between broken ice or snow in the beaker 
glass 6. Any liquid, condensing in the retort's neck, 



GREEN VITRIOL OR COPPERAS. 



45 



will flow back. Heating with burner 8 using a very 
small flame, we soon get the smell of sulfur oxyd alone 
at 7, and later on associated with white fumes. At 
the same time the walls of the U-tube become frosted 
over with white, needle-shaped crystals. When the 
temperature has risen to 300 C., we stop heating and 
remove the U-tube ; noticing the fumes arising from 
the cold substance in the tube, as soon as moist air 
comes in contact with it. Now let us change the* 
position of the retort by turning the swivel of the 

FIG. 24. 




clamp holder. The neck points downward, Fig. 24, 
and reaches into a dry test-tube. Raise the heat 
so that the liquid gets into boiling commotion. 
Streaks and streamers of thick liquid will run down 
the neck and collect in the test-tube 8. Hence it 
follows that by heat we can split the oil of vitriol 
into three parts : a gas (sulfur-oxyd); a solid (?); a 
liquid residue (?). The question-marks stand for : 
must be found out. 

The liquid residue. Let it be acted upon by the 
metals. Bring about 2 c.c. of the liquid in a test-tube 



46 CHEMISTRY SIMPLIFIED. 

together with a piece of copper foil. No action is 
noticeable until we heat, when effervescence ensues. 
(Effervescence means frothing due to rapid produc- 
tion of gas bubbles in a liquid.) The smell charac- 
terizes the escaping gas as sulfur oxyd. Further we 
notice the forming of a grayish, granular substance, 
and the copper foil has disappeared ; it has become 
changed or converted into the white granular sub- 
stance. These interesting facts lead us to a suppo- 
sition or hypothesis that our liquid must contain an 
oxyd of sulfur containing more oxygen than the gasi- 
form oxyd. If the latter be symbolized as S n O m , 
then the hypothetical oxyd would be S n O m + p in 
which symbol p denotes the mass units of oxygen 
which were given over to the copper enabling the 
latter to go into solution, through the abstrac- 
tion of this oxygen from the higher oxyd to form 
the lower sulfur oxyd with its characteristic smell. 
But in order to verify the supposition we must ex- 
amine the white granular product of the action. We 
pour off the liquid, add water to the granular resi- 
due, and see it go rapidly into solution with a pale- 
blue color. The solution we evaporate on a water- 
bath. At a certain point of the evaporation a solid 
begins to form. We allow the liquid to cool and a 
larger crop of blue crystals will form. The crystals 
are translucent, show an oblique symmetry, in fact 
resemble the crystals of our original vitriol. Hence 
the deduction will be rational that the crystals are 
copper vitriol. (A crystal placed upon a knife blade 
with a drop of water produces a bright copper spot 



OF THE 

UNIVERSITY 

OF 

COPPERAS. 47 



upon the blade.) We dry the crystals between filter 
paper and bring some into a closed tube. On heating, 
as in the original experiment, we observe water first, 
and the vitriol turns white. At higher heat, full 
redness, we note some sulfur oxyd gas, and at still 
higher heat, when the glass begins to melt, a ring 
of oily liquid (oil of vitriol). On cooling the vitriol 
has become jet black, and the black body, under the 
circumstances is evidently copper oxyd. The chain 
of evidence is complete. This copper oxyd must 
have been contained in the copper vitriol. And hav- 
ing put metallic copper into the liquid, the copper 
oxyd can only have formed by taking oxygen from 
a higher oxyd present. The latter is an oxyd of 
sulfur, because sulfur oxyd forms during the opera- 
tion. We symbolize the operation or action thus : 

pCu + 2pS n O m +P = pCuO.S n O m +P + pS n O m . 

A vitriol thus defines itself as the combination of 
a metallic oxyd with sulfur peroxyd, the syllable per 
meaning more. Both vitriols contain water, but 
that does not mean that all vitriols must contain 
water. 

ACTION OF THE LIQUID RESIDUE UPON LEAD AND 
SILVER. 

If we bring a piece of lead foil or very thin 'sheet 
lead into a test-tube with the liquid residue, there is 
no action at the ordinary temperature. On heating 
we notice a whitish film on the metal which again 
disappears. But on further heating there is at once 



48 CHEMISTRY SIMPLIFIED. 

an impetuous action, with formation of sulfur oxyd 
gas and a very fine granular white substance. Like- 
wise a yellow streak appears in the upper part of 
the tube. Lead vitriol is white and remains white 
when we add water, and furthermore does not dis- 
solve even in a very large amount of water. We 
collect the white substance on a filter, wash it thor- 
oughly and let it become dry in the air. In the 
closed tube, when heated to redness it gives no water, 
but over the gas blow-pipe it decomposes leaving 
yellow lead oxyd, the latter entering into combina- 
tion with the glass at this high heat, forming a 
yellow transparent compound. 

The yellow streak on the upper tube we can 
readily prove to be sulfur. We crack off the tube 
near the streak, wash thoroughly with water, dry 
and then heat over a flame. The yellow streak will 
melt and then burn with a blue flame, giving the 
smell of sulfur oxyd. This fact, teaches us that, 
while under ordinary conditions a metal takes from 
sulfur peroxyd only enough oxygen to convert the 
peroxyd into the oxyd, under extraordinary condi- 
tions of stimulated chemical activity, the oxygen 
may be taken away altogether from the peroxyd, 
leaving sulfur in the free state. 

We bring a piece of silver foil into the liquid 
residue and heat, when action sets in, the foil dis- 
appearing, without being changed into a solid res- 
idue ; in other words, the silver vitriol is soluble 
in the liquid. If water be added to the cooled 
liquid, cautiously, a white crystalline powder will 



GREEN VITRIOL OR COPPERAS. 49 

soon fall out, but will again dissolve when much 
water is added, that is, the silver vitriol is soluble 
in water and soluble in the concentrated liquid 
residue, but not soluble in the moderately dilute 
liquid residue. Of the solution of the silver vitriol 
we will soon be able to make some important use. 
Gold is not attacked by the liquid residue, and hence 
a very important deduction follows that if gold and 
silver are united in the form of an alloy, they may 
be separated by means of this liquid residue, and are 
thus separated in the Mint and the Metal Refineries. 

INVESTIGATION OF THE SOLIDIFIED OR CRYSTALLIZED 
WHITE FUMES. 

We take now the U-tube which contains the snowy 
deposit. We notice the inner surface of the corks 
strongly blackened (same action as shown by the oil 
as well as the fumes, even at ordinary temperature). 
On pulling the cork white fumes develop (again like 
the oil). We let a drop of water run down the side 
of the glass. A hissing noise is produced, and a drop 
of heavy, oily liquid, runs to the bend of the U. By 
adding drop after drop of water, we convert all the 
solid, snowy substance into the brownish-colored 
liquid, which latter, by this time, has become burn- 
ing hot. We act with this liquid upon the metals 
as we did with the Liquid Residue. The action is 
exactly the same in both cases, forming vitriol and 
sulfur oxyd. Hence it follows that the solid product 
from the distillation of the oil of vitriol, or in other 
words, the white fume must be sulfur peroxyd. But 
4 



50 CHEMISTRY SIMPLIFIED. 

then it follows inversely that if the sulfur peroxyd 
be converted by water into a liquid, whose action is 
the same as the Liquid Residue, then the latter 
must be sulfur peroxyd plus water. Stated sym- 
bolically this means 

White fume = S n O m + p = Sulfur peroxyd. 

Liquid Eesidue == S n O m +P. H 2 = Sulfur per- 
oxy-hydroxyd. 

Sulfur oxyd = S n O m . 

Oil of Vitriol = S n O m + P. H 2 + S n O m +P + S n O m . 

And since sulfur oxyd and sulfur peroxyd are 
expelled from the oil by heat, we express the pre- 
vious condition by saying : Sulfur oxyd and sulfur 
peroxyd are dissolved in the sulfur peroxy-hydroxyd, 
and thus form the oil of vitriol. The latter is a 
stable compound of the two oxyds, which cannot be 
broken up by boiling ; it distills over at 326 C. 
without decomposition. Instead of saying sulfur 
peroxy-hydroxyd we will say in future sulfuric acid, 
because the substance has eminently the characters 
of an acid body ; but the other name expresses 
better its make-up. 

DIRECT PROOF OF THE PRESENCE OF WATER IN THE 
SULFURIC ACID. 

By holding before us the actions of this sub- 
stance upon the metals which we have observed we 
can deduce, among others, the following reasoning : 
(a) If lead is converted by the acid into a vitriol, 
i. e., a combination of lead oxyd with sulfur per- 
oxyd plus sulfur oxyd we must get lead vitriol also. 



GREEN VITRIOL OR COPPERAS. 51 

by bringing together lead oxyd plus sulfuric acid 
without the forming of sulfur oxyd. (b) Lead vit- 
riol does not take up water, (c) Therefore if we 
mixed thoroughly an excess of yellow lead oxyd 
with a certain quantity of sulfuric acid, then the 
water must be liberated if any be contained in the 
acid. 

In order to reduce the argument to trial, we shall 
mix 5 c.c. of concentrated sulfuric acid with 50 
grams of yellow lead oxyd in a small wedge-wood 
mortar until the paste is almost powder. We fill 
this into a test-tube. Place the latter in a horizon- 
tal position as shown in Fig. 25, where 1 is the tube 

FIG. 25. 
I H 

MA T4. w V J 





holding the mixture 3/ with a delivery tube passing 
through the jacket J fed with cold hydrant water H, 
which runs through the discharge tube D into the 
sink. Almost at once, after applying a flame gently 
back and forth under Jf, a condensation of mobile 
liquid, water in fact, takes place at W t much steam 
passes into the tube, is condensed by the cold jacket 
and collects in test-tube R. The first distillate is 



52 CHEMISTRY SIMPLIFIED. 

nearly, not altogether, pure water. It will show 
acid reaction to litmus ; but if one cubic centimeter 
be drawn out and weighed, the weight will be so 
nearly one gram, that for our purposes we may ac- 
cept it as one gram and thus experimentally show 
the sameness with water. We have proved that 
sulfuric acid is 



or in other words that it is a vitriol in which hy- 
drogen oxyd takes the place of other metallic oxyds. 
SO 2 . We have arrived at a stage of development 
when we will be able to reason out the ratio in 
which sulfur and oxygen are united in the gasiform 
sulfur oxyd. Let us make a bent (knee-shaped) tube 
K, Fig. 26. Fill it with mercury and hold it with a 




proper clamp and stand in the mercury trough P. 
By heating a certain peroxyd (known as potassium 
chlorate) in a test-tube we can easily make pure 
oxygen gas and cause it to rise in the knee-tube 
until the mercury shall drop to an arbitrary mark 
M. We will then shove a piece of sulfur under the 
opening and let it rise to the surface. A piece of 
soft copper wire rolled into a spiral at one end will 



GREEN VITRIOL OR COPPERAS. 53 

enable us to push the sulfur to the end of the tube 
at 5. A strip of gummed paper can now be used to 
mark the new mercury level. If a flame be now 
brought under 5, by slow degrees to avoid crack- 
ing the glass, then 5 be strongly heated to the 
point of ignition of sulfur, we will suddenly see 
the mercury get into strong up-and-down motion. 
This means that union between sulfur and oxygen 
has taken place. Heating is stopped when the mer- 
cury has become quiet. When the apparatus has 
returned to the temperature of the room, we find 
that the mercury has risen to the mark. Hence it 
is evident that oxygen changes into sulfur oxyd 
without change of volume. Or we can say one vol- 
ume of S n O m contains one volume of O. But how 
much sulfur has entered into the volume? Evi- 
dently we find this by subtracting the weight of one 
volume of oxygen from the weight of one volume of 
S n O m . Let the latter be W and the former W, 
then 

W . _ W == S' (weight of sulfur in the gas). 
Now we need only to know how much one vol- 
ume of sulfur weighs to solve our problem. These 
values have been determined and reduced to air as 
unity ; they are 

1 vol. S n O m == 2.210 : hence W W= (2.21 1.105) 
1vol. -1.105: =1.105 

1 vol. S =2.200: = S' 

: so S' = J S 

: because -l - 



54 CHEMISTRY SIMPLIFIED. 

hence follows SO 2 as expressing the volume ratio 
between the two bodies. 

Thus we see that 1J volumes of the free gases 
when combined only occupy one volume con- 
densation of one-third. The same was true of 
hydrogen and oxygen when they combined to water. 

If the true numerical symbol for sulfur oxyd be 
SO 2 , which we necessarily pronounce sulfur dioxyd, 
what is the symbol of the sulfur peroxyd? The 
answer is SO 3 . You will prove this yourselves at a 
later stage of this course, and just simply accept the 
fact. The vitriols are therefore : 

H 2 O.S0 3 =Hydroxyd vitriol = Sulfuric acid. 

CuO.SO 3 = Copper oxyd vitriol = Copper vitriol. 

PbO.SO 3 =Lead oxyd vitriol = Lead vitriol. 

ZnO.SO 3 = Zinc oxyd vitriol = Zinc vitriol. 

FeO.S0 3 =Iron oxyd vitriol = Iron vitriol = 
copperas. 

Ag 2 0. SO 8 = Silver oxyd vitriol = Silver vitriol. 

The writing of silver oxyd Ag 2 is based upon 
experiments and reasonings which we cannot now 
go into, but which will appear shortly. 

The dilution of sulfuric acid. If we make that 
experiment in which we proved the presence of 
water in the liquid residue or the concentrated sul- 
furic acid, with great care, weighing the acid taken 
and weighing the water which results, we obtain in 
a given experiment, when we took 20.54 grams of 
the acid, 3.77 grams of water; hence the concen- 
trated acid contains in 20.54 grams: SO 3 equal 
16.77; H 2 = 3.77. We also know that S = 20, 



GREEN VITRIOL OR COPPERAS. 55 

that is, the sulfur as gas weighs for equal volumes 
twice the oxygen, S = 32, therefore 
1 sulfur = 32 X 1 = 32. Also 2H = 2x1= 2 
3 oxygen = 16 X 3 = 48. 1 oxygen = 16 X 1 = 16 

Sum 80 Sum 18 

The numbers 80 and 18 stand for the mass units of 
SO 3 and IPO, or as other chemists say, they repre- 
sent their molecular weights. The experiment gave us 
SO 3 =16.77: 80 = 0/2096: 1 
H 0= 3.77: IS = 0.2094 '- 1 

By dividing into these numbers the molecular 
weights, we change the weight numbers into molec- 
ular quantities. We get equal quotients and have 
thus established that the symbol H 2 O.S0 3 is the 
true quantitative expression for that concentrated 
acid, which distills without breaking up. 

We take this concentrated acid and add water, 
mixing the two ; the mixture becomes hot. We 
conclude of necessity that a chemical union has 
been effected. Let the addition of water be rational 
instead of arbitrary. Let the quantity of concen- 
trated acid taken be 100 grams, which contain : SO 3 
= 81.6 ; IPO = 18.4. By adding with a graduated 
tube or cylinder 18.4 c.c., we will have added just 
one other mass-unit of water ; the resultant liquid 
will be 

H 2 O.S0 3 .H 2 = ml/uric acid monohydrate, 
containing in 100 parts : SO 3 = 68.9 ; IPO = 31.1. 
After this liquid has resumed the normal tempera- 



56 CHEMISTRY SIMPLIFIED. 

ture of the room, we take of it again 100 grams, add 
to this 18.4 grams of water, and mixing, find again 
a rise of temperature, but much less than before. 
Unquestionably another chemical union of lesser 
strength of hold, the 

H 2 O.S0 3 .2H 2 = sulfuric acid dihydrate, 
containing in 100 parts : SO 3 = 58.2 ; H 2 = 41.8. 
Repeating the operation a third time a very slight 
rise in temperature follows. Hence we conclude 
that the 

H 2 O.S0 3 .3H 2 == sulfuric acid trihydrate, 
containing in 100 parts : SO 3 =49.2 ; IPO =50.8 
is the last hydrate. Beyond this figure water is not 
held in chemical, only in mechanical, union, which 
we can very properly express by the symbol 
H 2 O.S0 3 .3H 2 + aq., 

in which aq. stands for Latin aqua == water ; this 
is dilute acid. 

ACTION OF HYDRATES OF SULFURIC ACID UPON THE 
METALS. 

The mono- and di-hydrate act in a boiling solution 
the same as the acid upon lead and copper, that is, 
SO 2 is disengaged and the vitriols form. The trihy- 
drate does not act upon lead or copper. . But if we 
bring this trihydrate upon zinc or iron a violent evo- 
lution of gas results. The gas, however, is not SO 2 . 
It has a peculiar odor, more marked with the iron 
than with the zinc. But the gas is inflammable, 
and if the flame is inside a cold test-tube, water 



GREEN VITRIOL OR COPPERAS. 57 

condenses fast. The gas is, therefore, mostly hydro- 
gen ; the odor coming from other bodies contained 
in the iron and zinc, so-called impurities. The pro- 
cess may be represented by symbols, thus 

H 2 O.S0 3 .3H 2 + aq. + Zn == ZnO.SO 3 + 3H 2 

-h aq. + H 2 , 

for if the liquid be evaporated after the action, zinc 
vitriol crystallizes. In other words, we may de- 
scribe the process thus : Zinc oxyd has a stronger 
tendency to form vitriol than hydrogen oxyd. The 
zinc therefore takes the oxygen away from the latter 
and thus liberates hydrogen. We may extend this 
idea to the former reaction, where SO 2 is evolved, 
thus 

Zn + H 2 O.S0 3 == ZnO.SC 8 + H 2 . 
H 2 + H a O.S0 8 == SO 2 + 2H 2 O. 

The power inherent in " nascent " hydrogen is such 
that it will decompose SO 3 into SO 2 -j- IPO, but 
this power does not exist in the dilute solution. The 
result is just the same as if we say the metal, zinc 
for instance, takes the oxygen from SO 3 . 

Acting upon iron chips with dilute sulfuric acid, 
we get finally a muddy, dark -colored solution and 
the hydrogen gas is strongly tainted with other gas 
of a fetid, unpleasant odor. When the liquid 
stands, it gradually becomes clear with a bluish- 
green color, a black sediment having fallen to the 
bottom. We remove this by filtration and find that 
the dried, black substance can be burnt like coal ; it 
is a peculiar kind of coal called graphite, and the 



58 CHEMISTRY SIMPLIFIED. 

fetid gas is a combination of the coal with hydrogen 
(C n H m ). Zinc likewise leaves a residue, but this 
does not burn. We shall see at a later stage that the 
residue is due to certain metals and non-metals, 
always present in the crude, commercial zinc. But 
let us return to the bluish-green liquid. We will 
evaporate the liquid upon a water-bath until a crust 
forms over the surface, which signifies the beginning 
of crystallization. Then we set it away over night 
and find next morning a crop of greenish crystals. 
They are identical in form with the vitriol we 
started our experiments with ; they also act in the 
closed tube in the same way, when heated. We 
have thus a direct proof that vitriol, the so-called 
copperas, is iron vitriol. Yet when we take the 
red solid residue obtained from the destructive heat- 
ing of the copperas, and boil that body with sulfuric 
acid and trihydrate, we get a yellow solution, from 
which, by evaporation, yellow, scaly crystals are 
deposited. This is an undoubted vitriol, but not 
copperas, yet containing all the elements of the 
latter. Hence no other deduction is possible than 
the following : There must be two oxyds of iron, as 
we found a red and a black oxyd of copper, an SO 2 
and an SO 3 . These oxyds are presumably FeO 
and FeO 2 . But which of these is in copperas, and 
which is in the yellow crystals ? A very neat little 
process of inductive reasoning will give us the an- 
swer. It has been observed at the beginning of this 
chapter that when a solution of copperas in water 
stands exposed to the air, a yellow film will form at 



GREEN VITRIOL OR COPPERAS. 59 

the surface. That this must be due to the action of 
oxygen, because in azote, no such film comes into 
being. We can accelerate the forming of the yellow 
precipitate by blowing air into the liquid. If we 
dissolve this yellow solid (after separating it from 
the liquid by filtration) in dilute sulfuric acid, we 
get, after evaporation, the same yellow crystals as 
we did from the red oxyd + sulfuric acid, and if we 
heat the yellow substance (not the crystals) we get 
in fact the red oxyd. Therefore it follows that cop- 
peras contains the lower oxyd, and the red oxyd is 
the higher oxyd. Just how the proportions of oxy- 
gen and iron stand we cannot, now, prove; but let 
us assume that this proportion is 1/1 for the lower 
and 2/3 for the higher oxyd. Then we can write 

Fe + H 2 O.S0 3 + aq. = FeO.SO 3 + aq. + H 2 , 

but we can explain, even now, why we get so much 
SO 2 in the earlier stages of vitriol distillation. 
Namely : SO 3 we saw is a strong oxidizing agent, 
and hence *the lower iron oxyd changes at its ex- 
pense into the higher oxyd. 

2(FeO.S0 3 ) + 7H 2 + heat = 7H 2 + SO 2 + 

SO 3 + Fe 2 O 3 . 

We must of necessity get just as many molecules of 
SO 2 as we can get of the more useful oil forming SO 3 . 

Practical application of some parts of the lesson of 
oil of vitriol. 1. How to prepare, on occasion of 
need, sulfur dioxyd (SO 2 ). A 250 c.c. flask 2 is 
filled to about one-half with thin lathe chips of cop- 
per. The stopper funnel 1, Fig. 27, is filled with 



60 



CHEMISTRY SIMPLIFIED. 



sulfuric acid monohydrate. B is a burner ; 4 a 
wash-tube partly filled with water ; 5 a drying tube, 
one-fourth filled with concentrated sulfuric acid, and 
6 a bulb tube filled with glass beads which have 
been moistened with concentrated sulfuric acid. 
Why? Because up to a certain point we have 



FIG. 27. 




found an extraordinary attraction of this acid for 
moisture. Now if the acid flows from 1 into # upon 
the chips, while heat is properly applied, a stream 
of pure SO 2 will soon displace all the air from flask 
and tubes, so that presently pure, dry gas issues from 
6 ready for any desired purpose. When dry gas is 
not required, the tubes 5 and 6 are left out. After the 
chips are used up, the flask must be cleaned out ; it 
is best though to clean it out immediately after the 



GREEN VITRIOL OR COPPERAS. 61 

need is past, because the vitriol will become as hard 
as rock and the flask be much in danger. 

2. How to Generate Hydrogen. This substance is 
very often required, and in large quantities, for 
filling a balloon, for instance. For small quantities 
you may use the apparatus just preceding, Fig. 27. 
The flask 2 is partly filled in this case with granu- 
lated zinc, and dilute acid is fed into the funnel 1. 
Make the acid 1:20, that is, 20 volumes of water 
for one volume of the acid. You will find that 
such a simple contrivance is all right for a small 
volume of gas, but not for more, and what you do 
get comes very fast at first, then ever slower. Why? 
Because the dilute acid becomes a solution of zinc 
vitriol, which renders the acid more and more weak. 
Many devices have been designed to get a better 
result. The adjoining figure, Fig. 28, shows my 
own design, which has given complete satisfaction 
to all those who gave it an intelligent trial. The 
principal part of the apparatus is a glass tube G 
drawn slightly into a neck N, and at the lower end 
into a narrow tube 0, to which latter is fitted a 
stout rubber tube R. The latter forms a U, has a 
glass nozzle P, and thus discharges the dilute solu- 
tion of zinc vitriol into the glass jar TT. This tube 
G, which we better name the " generator " is filled 
with the granulated zinc. It is surrounded by a 
wider tube / which is melted at both ends together 
with the generator, thus forming a jacket. The 
latter can be filled with water through the tubula- 
ture E. The function of the jacket is to keep up a 



62 



CHEMIbTRY SIMPLIFIED. 
FIG. 28. 




B 



KOENIG'S GENERATOR. 



GREEN VITRIOL OR COPPERAS. 63 

temperature of about 70 C. in the generator. To 
this end a 5-millimeter glass tube t has been 
melted into the jacket obliquely. The middle 
portion of the tube is of brass and is here heated by 
a little flame which burns from a glass tube or from 
a Bunsen burner. A rubber stopper closes the neck 
N and through it passes the funnel tube F which 
should be 12 inches long. The whole apparatus is 
held in vertical position upon two brackets which 
may either be attached to a portable stand Q or may 
be put against the wall under the hood permanently. 
The zinc is prevented from falling into the rubber 
tube by the " false bottom " D made of porcelain. 
After the jacket has become hot you fill the bulb of 
the funnel with the dilute sulphuric acid 1:20, and 
also fill water into the generator until it begins to 
run from the nozzle P. Now open the stopcock of the 
funnel so much that a drop falls from the stem 
every second, and soon a steady stream of hydrogen 
will issue from the tubulature L. The gas will be 
free from air sooner than in any other form of 
generator. The gas will be washed and dried as 
shown above. When the column of zinc has fallen 
by three inches, it should be filled up ; but that in- 
cludes a steady running for a whole day. For 
much use, a large reservoir bottle, holding the 
dilute acid, should be rigged up above the funnel, 
so that the acid can be drawn into the cup of the 
funnel by means of a syphon. 



CHAPTER IV. 

THE LESSON OF LIMESTONE. 

WE have before us three productions of nature, 
which to the eye are very different. The first is a 
large crystal of dog-toothed spar, calcspar or cal- 
cite, quite common in our copper mines, notably at 
the Quincy Mine, where it is intimately associated 
with the native copper. This particular crystal 
comes from the zinc-lead mines of Joplin, S. W. 
Missouri. You will notice that one end of the crys- 
tal shows three lustrous faces intersecting over the 
edges at an angle of a hundred and five degrees 
nearly a rhombohedron whilst the other end 
shows six faces intersecting at alternately different 
angles a scalenohedron because the faces are 
scalene triangles thus producing the impression of 
a dog's fang. Parallel to the faces of the rhombo- 
hedron the mineral cleaves perfectly. I cleave off 
a piece and you see a small rhombohedron exactly 
similar to the original one. It is both colorless and 
transparent, and if placed upon this cross upon 
white paper we see the lines of the cross double; the 
two images are close together. The physicists say 
the mineral has double refraction and give you an 
explanation according to the present state of their 
knowledge. From this property the mineral is 

(64) ' 



THE LESSON OF LIMESTONE. 65 

sometimes called double-spar (the latter word, spar, 
is given to all minerals which are more or less 
transparent and show strong cleavage). 

The second specimen is this whitish rock which 
is known as crystalline limestone. It shows num- 
bers of small but splendent faces, each of which is 
in reality the face of a rhombohedron similar to that 
of the calcite : or in other words the rock is made up 
of innumerable calcite rhombohedrons which pre- 
vented each other from developing individual geo- 
metric independence. 

The third specimen is this dull gray rock com- 
monly known as limestone. In its appearance there 
is nothing in common with the previous specimens. 
But all three possess nearly the same relative weight 
(specific gravity), and an equal power of resistance 
to a penetrating steel point (equal hardness). The 
comparison thus far made we call physical, mean- 
ing therewith that all the given properties have 
been ascertained without destroying the identity of 
the original substance. Let us now act upon these 
materials with the powerful agents in our posses- 
sion, whereby the original identity will become 
modified or wholly destroyed, new bodies being 
produced. The knowledge thus gained will be 
chemical knowledge, and will greatly widen out our 
horizon as to the nature of things. 

1. Action of heat. Place a fragment of calcite 

in a glass tube closed at one end, and heat this 

end to high redness. No odor ; fragment turns dull 

chalky. It might nevertheless be that an odorless 

5 



66 



CHEMISTRY SIMPLIFIED. 



gas is evolved. Contrive a rig as sketched in Fig. 
29, wherein t is the hard glass tube with the frag- 
ments. B B are two bricks to concentrate and re- 
flect the heat rays upon the tube. T is a test-tube 
filled with water and t' a short bent glass tube at- 
tached to t by a short piece of rubber tubing. The 
heat may be produced by means of a blast lamp or 
by placing over the tube t several pieces of charcoal 
made incandescent and by then fanning them into 
combustion by an air blast or by means of an ordi- 

FIG. 29. 




nary fan. The heating with coal is much more 
satisfactory than with the blast lamp. 

When the tube has come to red heat, we observe 
a steady current of gas bubble through the water 
into the test-tube. The gas is odorless and evi- 
dently not soluble in water to any considerable ex- 
tent. Now we found the gas from the copperas to 
give a sour taste to the water, aside from the strong, 
pungent odor ; hence we examine the present gas in 
the same direction. Water is not changed to the 
taste but blue litmus paper is slightly reddened. 
We say the lime gas has a weak acid nature. It 
does not burn or explode as hydrogen and does 



THE LESSON OF LIMESTONE. 67 

not stimulate or increase a burning as oxygen. 
It is of all gases thus far encountered most like 
azote. But in making soap bubbles with it, the 
latter immediately fail to the floor ; hence the gas 
must be much heavier than air or azote (the latter 
being -f of the air) and moreover azote does not im- 
part sour or acid properties to the water. Thus we 
are forced to the conclusion that this lime gas is a 
new body. But if so, we ask, is it a simple or com- 
pound body ? In order to find answer to this ques- 
tion, let us do some reasoning by comparison : The 
copperas or iron vitriol is crystallized or transpar- 
ent ; it has been proven to be composed of two 
oxides + water. Calcite is crystallized and trans- 
parent, gives off a slightly acid gas and leaves a 
white opaque solid. Hence we will be justified in 
the assumption that calcite also is composed of two 
oxyds, one metallic, the other non-metallic. 



This is an hypothesis (the word is the Greek equiva- 
lent for either supposition or assumption). 

Proof for the gaseous or volatile part. If the gas be 
an oxyd like water (as steam) it may be possible to 
break it up by a metal such as zinc, or, as we saw 
with the oxyds of iron and copper, heat and char- 
coal might do it. Let us choose zinc in the form of 
these bright chips. It will be necessary to produce 
a small but steady current of the lime gas. Having 
seen that both dilute sulfuric acid and vinegar can 
decompose the calcite and the limestone, we choose 



68 



CHEMISTRY SIMPLIFIED. 



the vinegar. Why ? Because the latter gives a so- 
luble product, whilst the sulfuric acid gives a milky 
solution or a white mush, an insoluble vitriol. In 
the flask F (Fig. 30) bring about 20 grams of finely 
ground calcite or limestone with about 50 c.c. of 
water. Into the funnel V pour concentrated vine- 
gar acid, acetic acid, because the Latin word for 
vinegar is acetum. With the help of a small 
flame a steady current of gas can be made for quite 



FIG. 30. 



V 




T 




s 




a while, admitting more acid in small portions as 
needed. In the hard-glass tube T at Z lay the zincj 
chips between two asbestus plugs. The flame L 
will bring Z to red heat. Stand S with clamp K 
holds T in position. But since we want to prove 
an oxyd, it is evident that such proof would become 
impossible if the gas were to enter T at once, for the 
gas is charged with water vapor and we know that 
water will yield oxyd when brought together with 
red-hot zinc. We therefore interpose the test-tube 
D which is partly filled with concentrated sulfuric 



THE LESSON OF LIMESTONE. 69 

acid, through which the gas will have to rise in 
bubbles. We do this because we found that oil of 
vitriol absorbs water with very great energy. It is 
a dryer. Had we not observed well and noted this 
property we would now stand before an impassable 
obstacle. But going as we do, the discoveries come 
apace with their immediate practical application. 
Xow we begin the generation of the gas. The 
latter, being heavier than air, forms a steadily 
thickening layer over the liquid in F, driving the 
air before it and out of the entire apparatus. We 
keep on patiently until at least two volumes equal 
to F have been generated to make quite sure that 
the air is completely displaced. For if any remain 
our results could not be conclusive, since some zinc 
oxyd would surely.be formed, whether the lime gas 
were an oxyd or not. Zinc is coming to redness ; a 
white cloud appears on the glass. But in order to 
find what becomes of the gas let a rubber tube be 
brought under a test-tube G filled with water, and 
it will be seen that the tube soon fills with a color- 
less, inflammable gas. The zinc is oxydized. Now 
we may assume that the inflammable gas is the 
element Y or a lower oxyd of Y and symbolize thus : 

YPO + qZn + red heat = YP + qZnO 
or 

YPO + Zn + red heat YPQ^ 1 + ZnO. 

This alternative brings us up against the wall once 
more. Unless we shall happen to discover a metal 
with greater attraction for oxygen than the zinc, we 
shall not be able to prove directly that the com- 



70 CHEMISTRY SIMPLIFIED. 

bustible gas is an element or a lower oxyd. Let us 
not despair ; of wonders and signs of wonders there 
is no end. 

Study of the residuum. In order that this residue 
may be as much freed from the gas as possible, let 
us pour it from the glass tube into this platinum 
crucible. This latter being infusible we may con- 
centrate upon it a much higher heat than was pos- 
sible in the glass tube. Lifting the lid we see the 
pieces emit a white glow, whilst the metal of the 
crucible is only yellow. We say the lime is highly 
incandescent. The pieces still show the rhombo- 
hedrons of cleavage ; there is even luster upon the 
faces. The volume is the same but the weight has 
decreased 44 per centum. Cohesion has decreased. 
This residue is known as burnt lime caustic lime 
(" caustic" being merely the Greek for burnt). It has 
been known for ages to both civilized and savage 
peoples. Since limestone forms the surface rock for 
many square miles in large tracts of country all 
over the earth, the first burnt lime was made when 
the first man living in a limestone country made 
a rough fireplace with the pieces of rock around 
him. According to our hypothesis burnt lime 
ought to be an oxyd X n O m , the oxyd of a metal X 
whose properties we do not know. For if we try 
upon this lime the same agents which yielded us 
the metal from the oxyds of iron and of copper, 
namely intense heat (by the blow-pipe) and char- 
coal, our trial will end in failure ; the white mate- 
rial remains quite unchanged. What was said of 



THE LESSON OF LIMESTONE. 71 

the final nature of the element Y above, applies 
here in regard to X. Let it stand for the present 
as X, or since we called Y the lime gas, let X be the 
lime metal We may even designate by the symbol 
Ca (the first letters of the word calcite), since we 
designate iron by the symbol Fe (the first letters of 
the word ferrum)-, yet ever bear in mind that it is 
a suppositions, a hypothetical simple body of whose 
properties, in the first state, we are ignorant. This 
ignorance does not prevent us from studying the 
behavior, the properties of the supposed oxyd. 

First towards water. Let a drop of water fall upon 
some of the caustic lime, a hissing noise ensues ; a 
slight cloud of steam arises ; the lime swells up and 
falls into an extremely fine powder : Flour of lime. 
The flour can be dried at steam heat and yet this dry 
flour will yield water in the closed tube, at red heat, 
and lose 24.3 of its weight. After cooling moisten 
the lime and it will hiss with water as before and 
fall into flour. Hence we say the burnt lime has a 
very strong affinity for water, and will form with 
it a true union, a chemical compound, a hydroxyd, 
very much as the sulfur oxyd SO which forms 
the hydroxyd we called sulfuric acid. Deduction : 
Both metallic oxyds and non-metallic oxyds form hy- 
droxyds. 

Flour of lime = lime hydroxyd = Ca n O m .H 2 0. 

Adding more water the lime hydroxyd turns into 
a white paste : Slaked lime. If we add much water, 
shake and stir thoroughly and then let stand, we 
notice that apparently the whole of the white paste 



72 CHEMISTRY SIMPLIFIED. 

will settle, leaving a clear liquid above. Deduc- 
tion : Lime hydroxyd is very little if any soluble 
in water. However, the water has a decided taste, 
and turns reddened litmus paper to blue. Hence it 
is an agent, and we call it lime water. By evaporat- 
ing 1*00 c.c. in a weighed dish, we obtain a residue 
of hydroxyd of 0.1 gram 1000 lime water hold 1 
hydroxyd. 

Second, towards acids. Make a -^ p. c. solution of 
sulfuric acid and of vinegar or acetic acid. Because 
sulfuric acid has a specific gravity of 1.83, we will 
require 0.054 c.c. to give us 0.1 gram (1.83 : 1 = 
OJ : 0.054), that is, just one small drop for the 100 
c.c. of water. The strongest acetic acid has sp. grav. 
1.05, nearly the same as water. Two small drops 
of it will give the strength wanted with 100 c.c. of 
water. Pour 25 c.c. of each of these very diluted 
acids into 2 beaker glasses, add a little litmus solu- 
tion to each, which will produce red color. Now 
slowly add clear liine water from a graduate into 
the first beaker glass. All at once the red color 
changes to blue, when a certain number of c.c. have 
been added. The same with the acetic acid. We 
deduce : The two bodies of opposite action to litmus 
saturate each other so that a neutral body results, the . 
neutral body is the salt. Let M stand for any metal, 
and N for any non-metal, then 
M n O m .H 2 = hydroxyd = base 
N n O m .H 2 == hydroxyd = acid 
M n O m .H 2 O -f N n O m .H 2 = M n O m .N n O m (salt) -f 
2H 2 



THE LESSON OF LIMESTONE. 73 

The three conceptions are fundamental in chem- 
istry. Base, acid, salt. Yet neither base nor acid 
is to be understood in the absolute sense. Two 
metallic hydroxyds may act as base and acid 
towards each other, or in other words one is more 
basic than another. We shall find examples as we 
proceed. This much, however, impress upon your 
mind : An oxyd is rarely an active agent ; in order 
to make one oxyd act upon another oxyd strong 
external impulse is needed, such impulses being 
heat and electricity. The internal activity becomes 
manifest towards the surroundings with the forma- 
tion of the hydroxyd. This will become clearer in 
the next chapter. 

Allow a portion of the liquid, in which you have 
saturated the lime hydroxyd with the sulfuric acid, 
to evaporate on a watch crystal. Groups of crystals 
will be formed, colorless, needle-shaped. Examine 
them with a microscope. They are often stellar, 
that is, radiating from a centre. When heated 
these crystals will loose water readily ; they are 
CaO.SO 3 + 2H 2 O a vitriol in which two mole- 
cules of loosely-bound water of crystallization are 
tacked on to the salt proper as in iron vitriol and 
copper vitriol. 

Action of the lime gas upon the lime hydroxyd. 
Lime water is the iV per cent, solution of the lime 
or calcium hydroxyd in water. Generate the gas 
as above and let it bubble through some of the solu- 
tion in a test-tube ; a turbidity appears at once which 
gradually turns to a milky white color and white 



74 CHEMISTRY SIMPLIFIED. 

sediment. Filter this upon a small paper filter, 
dry it. It has no taste. Heat some of it to yellow 
heat upon a bit of sheet-iron (platinum preferable 
but too costly) ; after cooling transfer it to a slip of 
reddened litmus paper and moisten with one drop 
of water. Observe that it slakes and the litmus 
turns blue under the white mass. Place another 
minute quantity of dry precipitate upon a watch 
glass or plain glass slide and examine, after moisten- 
ing it, with a high power of the microscope. Minute 
but perfect transparent rhombohedrons appear. 
Hence deduction : Lime gas converts lime hydroxyd 
into calcite from which we started. High heat 
breaks up the combination of the two oxyds ; at low 
heat (temperature of room) they recornbine. Con- 
clusion : Very high heat always counteracts the 
chemical attraction, tends to separate the minute 
mass-units. Now let the lime gas bubble through 
another portion of the lime water and leave it for 
some time, being called away. On returning we find 
the original rnilkiness all gone ; evidently the calcite 
has been dissolved in an excess of gas. Boil the clear 
solution and shortly milkiness as well as sediment 
reappears. Conclusion : Boiling heat expells the 
solving excess of gas, the dissolved calcite being it- 
self almost insoluble (one part in 250,000 parts 
water), must precipitate. This is the reason why the 
hard water of limestone regions always gives a sedi- 
ment after boiling and the boiled water becomes 
soft. Here is some lime water which has been 
standing for quite a while in the open beaker glass. 



THE LESSON OF LIMESTONE. 75 

Note that a film has been forming on the surface. 
The film shows iridescence in strong sunlight. Re- 
move some to a glass ^ slide and you will find with 
a high power the identical rhombohedrons. De- 
duction : If calcite forms under these conditions it 
is evident that the lime gas must be part of the 
atmosphere. And since the film forms much 
more rapidly in a crowded room than outside, 
we must reason that lime gas forms part of the 
effluvia or gaseous emanations of the human 
body. Another important side-gain is that the 
hardening of mortar must be owing to the absorp- 
tion by the slaked lime of the lime gas in the air. 
Mortar is a mixture of 80 to 85 parts of sharp sand 
with 20 to 15 parts of quick-lime in the slaked 
condition. 

All the actions observed are identical for calcite, 
crystalline limestone and common limestone; their 
substance is identical, though their look is very 
different. This must be noticed, however, that the 
gas evolved from common limestone possesses a fetid 
odor which is owing to oily matter often contained 
in the limestone. * 

Summary of limestone lesson. Discovery of a gase- 
ous oxyd whose non-metal Y is at present unknown. 
Of a metallic oxyd (probably) whose action towards 
the acids is equal to the oxyds of iron and copper, 
though we do not know the metal contained therein. 
The oxyd differs by its tendency to form hydroxyd 
and by its action on litmus paper, which we call 
basic action. 



CHAPTER V. 
THE LESSON OF WOOD ASHES. 

WE have before us the familiar and homely 
material ashes. There are evidently two kinds. 
For in the one we find fragments of partly coaled 
wood, and in the other hard, glassy nodules known 
as clinkers. The first is the remnant from burning 
wood, the second the remnant from burning coal in 
a kitchen range. Why should I bring these mate- 
rials before you ? They look unpromising enough. 
Because I find, upon trial, that the wood ashes pro- 
duce a strong, biting taste similar to that of slaked 
lime, whereas the coal ashes show no taste what- 
ever. There must be something in the wood ashes 
outside of the ordinary earth calling for investiga- 
tion. The Roman historians tell us that when 
their armies came in contact with the Teutonic 
tribes on the Rhine, they found it a custom among 
these for the women to do up their hair with a kind 
of ointment, and this they made up from fat and 
wood ashes. It was indeed what later on was 
called soft soap. Whilst these people were at that 
time, 2,000 years ago, barbarians much like the 
American Indians, they had the spirit of investiga- 
tion stalking among them, and this spirit is stalk- 
ing among them now. When linen and woolen 

(76) 



THE LESSON OF WOOD ASHES. 77 

cloths had superseded the skins of animals, the 
original hair ointment was found to possess excel- 
lent cleansing properties ; the manufacture of soap 
became a separate trade, and wood ashes came to be an 
article of commerce. The early pioneer in America, 
for many years, had nothing to exchange for grocer- 
ies and other store goods but the ashes which he 
collected from burning out his clearings in the for- 
est. However, the valuable part of wood ashes is 
only about 30 per cent.; the storekeeper had no use 
for the 70 per cent, of waste. The farmers were 
made to extract the valuable portion with hot 
water, to strain the liquid through canvas, to boil 
down the liquid to solidity, in iron kettles or pots, 
hence the 'commercial product came to be called 
potash. This material is not yet pure ; it is of 
brown color, and contains other soluble parts of the 
ashes. It undergoes a refining process, becomes 
white, and goes under the name of pearl-ash. How- 
ever, wood has become so scarce everywhere that it 
can no longer be burnt for the sake of the ashes. 
How means were found to replace it successfully, in 
more recent times, we shall see in a following 
chapter. 

Investigation. We have boiled down the liquid 
the lye, " lie " (pronounce lee) in French, " lauge " in 
German. In Germany potash was called " laugen- 
salz " salt made from the lye. 

First let us see how the potash acts at high heat. 
We place some in a hard -glass tube closed at one 
end. First some water condenses in the upper tube. 



78 CHEMISTRY SIMPLIFIED. 

At red heat the substance becomes liquid, and then 
we observe small gas bubbles arising from the con- 
tact between the liquid and the glass, the mo- 
bility is changed to sluggish flow. Question : 
Have the escape of gas bubbles and change of flow 
anything to do with an action upon the glass? or 
is it inherent in the potash itself? To answer, let 
the glass tube be substituted by a metallic vessel, 
say an iron crucible. The potash melts as before 
but no bubbles come ; the liquidity remains the 
same. It follows that escape of gas is caused by in- 
teraction or reaction upon the glass. Potash is fusi- 
ble at red heat unchanged : remember this important 
fact. 

Act with sulfuric acid or acetic acid upon the 
dry potash and upon its solution in water. In 
either case there is strong effervescence. We apply 
the same procedure to the examination of the gas 
which we used with the lime gas. We find the gas 
in all its actions like the lime gas. Moreover, a 
white granular salt falls out when sulfuric acid de- 
composes the potash, a vitriol. Therefore we will 
be 'justified in the assumption that potash is com- 
posed of two oxyds : 

PO.Y n O m 

in which P as the first letter of potash, stands for a 
metal as yet unknown to us, because its vitriol is 
unlike the known vitriols in its crystal form, 
unlike also as to solubility, and especially unlike in 
this, that heat does not break it up ; the vitriol 
PO.SO 3 stands the heat of the blast-lamp, as I here 



THE LESSON OF WOOD ASHES. 79 

show you in the glass tube. The vitriol is more 
like the lime vitriol than like the iron and copper vit- 
riols ; since the action of potash and lime hydroxyd 
are both basic to litmus. Since heat neither breaks 
up the potash nor the potash vitriol, how shall we 
get at the hypothetical oxyd PO ? Let us reason : 
We found calcite insoluble, but convertible into 
oxyd. Suppose we bring the solution of potash 
together with the lime oxyd in this test-tube, and 
let this be represented by the scheme : 
PO.Y n O m + CaO + water. 

CaO will become slaked lime with the water, we 
will then get 

PO.Y n O m + CaO.H 2 + water + boiling heat. 
We notice turbidity at once, then flocculency, then 
a granular precipitate. We filter. The filtrate with 
sulfuric acid does not give gas, but a granular salt 
falls out slowly as the liquid cools. The action 
must, therefore, have been 



PO.H 2 + water 

the non-metallic oxyd Y n O m has gone to the lime, 
and only the hydroxyd PO.H 2 remains in solu- 
tion. The filtrate causes deeper action on the skin 
of the fingers, on litmus paper and on the tongue. 
It also follows that PO.H 2 is much more soluble 
in water than CaO.H 2 0. 

Potassium hydroxyd, caustic potash, caustic potassa, 
potassium hydrate. The first of these names I want 
you to use. The second and third names are older 



80 CHEMISTRY SIMPLIFIED. 

and still used in the drug trade ; the third name was 
the current scientific name and is used by the 
majority at present. But I want it to apply to a 
separate conception. To make myself clearly un- 
derstood we will return to the action of water upon 
oil of vitriol. Represented symbolically we have 
there to start with : 

H 2 O.SO a .nSO*. 

Adding water, little by little, there is much heat, 
also hissing noise, this lasting until the nSO 3 have 
combined with nH 2 and we have now only 

H 2 O.S0 3 

our concentrated sulfuric acid the true hydroxyd. 
But when you add to this more water, both being 
at ordinary temperature the liquid warms up and 
can even reach boiling heat. This heat means 
more chemical union and may be scheduled 

1st hydrate H 2 O.S0 3 .H 2 
2d hydrate H 2 O.S0 3 .2H 2 
3d hydrate H a O.S0 8 .3H 8 

nth hydrate H 2 O.S0 3 .nH 2 
and similarly : 

H 2 O.PO = hydroxyd 
1st hydrate H 2 O.PO.H 2 
2d hydrate H 2 O.P0.2H 2 

nth hydrate H 2 O.PO.nH 2 
The nth hydrate may be, in fact, what we would 



^ THE LESSON OF WOOD ASHES. 81 

otherwise designate a dilute water solution of the hy- 
droxyd. Returning to the matter immediately 
before us, we evaporate the water solution of 
H 2 O.PO to dryness in an iron, copper or silver dish. 
Glass and porcelain are strongly attacked. Prove 
this statement by using a small beaker glass and a 
porcelain crucible ; they are not destroyed but lose 
the lustrous surface and some of their material 
enters the liquid. After the mass has become dry 
at boiling-point of water, heat over an open flame. 
Soon fluidity will occur, more steam will be given 
off; at red heat white vapors appear and, using a 
small portion, it will slowly disappear : the hydroxyd 
is volatile at red heat. But how do we know that 
this material is hydroxyd still ; why is it not the 
oxyd, when the lime hydroxyd looses its water so 
readily at red heat ? Revolving in our minds all 
the actions heretofore performed, we remember that 
both iron and zinc decompose water at red heat ; it 
may even do so when the water is united strongly 
to another oxyd. The rig will be simple. A short 
piece of hard-glass, thick-walled tubing closed 
at one end ; a perforated stopper, a narrow tube 
drawn into a fine opening and inserted into the 
stopper will probably suffice. We introduce a piece 
of the problematic hydroxyd with some zinc shav- 
ings, insert the stopper, hold the tube by means of 
a clamp in inclined position and apply heat. With 
the melting of the hydroxyd, gas bubbles appear, 
and ere long the mass will want to froth out of the 
tube, the escaping gas burns, the flame deposits 
6 



82 CHEMISTRY SIMPLIFIED. 

drops of water against a cold dish the gas is hy- 
drogen. In symbols the action is 

PO.H 2 + Zn + heat == PO.ZnO + H 2 . 

After cooling we find that the mass is quite soluble in 
water, all but some remaining zinc chips. Here is 
one example of two metallic oxyds combining to 
form a salt, because one, PO, is more basic than the 
other, ZnO. Thus, whilst proving the hydroxyd, 
we have incidentally discovered that this latter is a 
most powerful agent, rivalling the sulfur hydroxyd. 
It corrodes the skin rapidly ; it destroys paper and 
sawdust ; it dissolves wool and hair, horn chips and 
many other bodies. In these actions many interest- 
ing and useful new 'substances are formed, some of 
which we will inquire into hereafter. We find our- 
selves now in possession of the two most powerful 
agents H 2 O.S0 3 and PO.H 2 0. Acting upon each 
other they produce the neutral vitriol PO.SO 3 and 
water. Acting separately, they lend us their latent 
power. 

Action of calcite, of potash, of lime hydroxyd, of 
potassium hydroxyd and their hydrates upon the water- 
soluble vitriols of iron, zinc, copper. The vitriols are 
in dilute solution (you). 

1. CaO.Y n O m + CuO.SO 3 + boiling heat, escape of 

gas, green precipitate. 
+ FeO.SO 3 , slight brownish precipi- 
tate. 
+ ZnO. SO 3 , no precipitate. 



THE LESSON OF WOOD ASHES. 

2. PO.Y n O m + CuO.SO 3 , at ord. temp, blue precip., 

at boiling turns black, 
-f- FeO.SO 3 , at ord. temp, light precip., 

at boiling turns dark. 
-f ZnO.SO 3 , at ord. temp, white precip., 

at boiling remains white. 

3. CaO.H 2 -f CuO.SO 3 , precipitate at ord. temp. 

and complete at boiling heat. 
+ FeO.SO 3 , precipitate at ord. temp. 

and complete at boiling heat. 
+ ZnO.SO 3 , precipitate at ord. temp. 

and complete at boiling heat. 

4. PO.H 2 -h CuO.SO 3 , first blue precipitate which 

turns black. 
+ FeO.SO 3 , light green precipitate 

which turns black. 
+ ZnO.SO 3 , white precipitate which 

dissolves in excess. 

It can easily be proved that the precipitates formed 
under (2) are the combinations of CuO, FeO, ZnO 
with Y n O m , whilst the PO combines with SO 3 . 
CuO. Y n O m turns black on boiling, because the CuO is 
not very basic and cannot hold on to the non metal- 
lic oxyd when the shattering power of heat-waves 
pounds upon the compound. The same is to be 
said about CuO.H 2 under (4) the CuO cannot hold 
on to the H 2 0. The white precipitate (4) in zinc 
solution ZnO. IPO dissolves in excess of the agent 
because the soluble salt PO.ZnO forms, thus 
First : ZnO.SO 3 -f PO.H 2 0=ZnO.H 2 0-hPO.S0 3 . 
Second: ZnO.H 2 0+PO.H 2 0= PO.ZnO + 2H 2 0. 



84 CHEMISTRY SIMPLIFIED. 

Of iron there are two vitriols a green and a yellow, 
the latter produced by acting upon iron with the 
hydroxyd H 2 O.SO 3 when SO 2 escapes instead of 
hydrogen. 

The green vitriol contains the oxyd FeO, the 
yellow vitriol contains the oxyd Fe 2 3 . The two 
vitriols act differently on our four agents. But the 
one important action is that of calcite for FeO.SO 3 -}- 
water -f CaO.Y n O m = no precipitate. 

Fe 2 3 .3S0 3 + water-fCaO.Y n O m = brown precipi- 
tate, the action being slow at ordinary temperatures, 
rapid when heat is applied. Hence we have here a 
means of separation for the two oxyds of the same 
metal. (Details for this in the Chemistry of the 
Metals.) Likewise if the vitriols of Cu, Fe, Zn were 
mixed together (the iron vitriol being of the green 
kind), we would be able to separate the oxyds for 
(Cu and Zn) vitriols precipitate by calcite or chalk 
and heat, separating the iron. The precipitate 
boiled with PO.H 2 will leave the CuO as a solid 
and take the ZnO in solution. Our wealth is in- 
creasing as we go along. 

The metal potassium. Having seen that the oxyd 
PO is not obtainable, but only the hydroxyd 
H 2 O.PO, and that this latter is quite volatile, their 
remains only one raw material, the potash. Though 
it be a salt, the peculiar nature of its non-metallic 
ox}^d makes it possible to be broken up by coal, at 
a white heat. Cut a piece of f " or V gas pipe P 
(Fig. 31) six inches long, fit on a cap C } an elbow 
E and a pipe R of same length, all joined by thread. 



THE LESSON OF WOOD ASHES. 85 

Fill P with a mixture of charcoal-coated iron chips, 
30 grams of fused potash, 10 grams of burnt lime. 
Screw on E and R and set into furnace F. The 
latter is heated with gasoline burner B, but a good 
wind furnace and coke will give a suitable heat also. 
In order to prevent the pipe from burning through, 
it is well to coat it over with several coats of char- 
motte or braise, a mixture of three parts of ground 
brick and one part of fat fire-clay. The pipe R 

FIG. 31. 




is kept cool by a wrapping of blotting paper upon 
which water drops from the hydrant or spigot. 
A cork stopper 5 with glass tube permits the gases 
to escape. The burnt lime was added to the charge 
to make the potash less fusible ; the iron to hold the 
charcoal down, preventing it from floating to the 
top. This charcoal-coated iron is made by heating 
iron chips and sugar together in a covered crucible 
until no more gases escape. After yellow heat has 
been reached, combustible gas will appear and burn 



86 CHEMISTRY SIMPLIFIED. 

at 5 with either a purplish or yellow flame. Keep up 
the fire for an hour, then cool down. A gray and 
black loose mass will be found in R If some be 
thrown into water a hissing will be heard and for a 
short time a fine purple flame. The black material 
is a mixture of small metallic pellets and a spongy 
substance. By returning this mass to a smaller 
apparatus, of exactly the same form, the metal can 
be distilled from the sponge and appears then almost 
pure in E. The electric current also decomposes the 
hydroxyd PO.H 2 thus : The metal deposits on the 

FIG. 32. 




negative pole (cathode) whilst hydrogen forms at the 
same pole and oxygen escapes at the positive pole. 

PO.IPO + current = P -f H 2 , -f O 2 
It is difficult to keep the metal from burning up 
again in presence of the oxygen surrounding it. 
The difficulty may be avoided by pouring some 
mercury into the crucible (Fig. 32) and some of the 
third potassium hydrate over it. If now the cruci- 



THE LESSON OF WOOD ASHES. 87 

ble be made the negative pole and the positive pole 
be a platinum wire, the metal potassium in the 
moment of liberation combines with the mercury, 
alloys with it, and thus is kept from the air. The 
product is the potassium amalgam Hg n P m . We 
place the latter in a small glass retort and distill 
off the mercury at 300 C. Potassium remains as a 
liquid. At a red heat it also becomes volatile and 
will fill the flask as a fine green vapor. The retort 
must be kept filled with hydrogen to keep out the 
oxygen of the air. 

Physical properties of the metal. Potassium has 
a silver-white color, strong metallic lustre. But in 
presence of air tarnishes at once, becoming covered 
with a gray film. Therefore, the metal must be kept 
under a liquid which does not contain oxygen such 
as kerosene. The metal is soft, like fresh putty at or- 
dinary temperature, becomes brittle below the freez- 
ing point ; that means it crystallizes, appearing in 
tetragonal pyramids. It melts at 62.5 C.; at red 
heat, 730 C., the liquid boils like water; the vapor 
is green. Its specific gravity is 0.865 (water 1), 
hence, it floats on water, but sinks in kerosene, sp. 
gr. 0.76 0.78. The specific heat or heat capacity 
is 0.166 (water = 1). 

Chemical properties. Potassium decomposes water 
with great energy, because of all metals it has the 
strongest affinity for oxygen. 

p + H 2 ==PO + H 2 

but since an attraction exists between the oxyd and 
the water the action really is 



88 



CHEMISTRY SIMPLIFIED. 



P + 2H 2 = PO.IPO + H 2 . 

For instance, if you wish to ignite coal-oil which 
floats on water, you would just throw a piece of 
potassium on the water, and the oil would be on fire 
at once. 

I said potassium had the strongest attraction for 
oxygen of any metal. Why, then, were we able to 
dislodge it by iron and by charcoal ? The answer 
is found in that potassium is so easily volatilized*. 
We could not separate the calcium from the lime 
oxyd, because the calcium is not volatile. 

Proof of the nature of the unknown Y in lime gas. 
Once in possession of potassium, we will try it upon 
the lime gas, which zinc only changed into com- 
bustible gas (see above), and of which we remained 

FIG. 33. 




doubtful whether it was Y or a lower oxyd of Y. 
Let the lime gas be generated from calcite, chalk, 
or limestone by means of the acetic acid as before. 
Let the gas bubble slowly through H 2 O.S0 3 , Fig. 
33, thence pass it into the combustion-tube t, in 



THE LESSON OP WOOD ASHES. 89 

which a piece of potassium has been placed at P. 
If the dish D contains the 6th potassium hydrate, 
as also the test-tube t, then there will be perfect 
absorption of the gas as soon as all the air is ex- 
pelled from the apparatus ; because we know that 
the potassium hydroxyd as well as the different 
hydrates, absorbs the gas energetically in order to 
become potash PO.Y n O m . Now let the potassium be 
heated with the lamp L. It melts, spreading over 
the glass and forming a perfect metallic mirror. 
Then it ignites and burns with the characteristic 
purple flame almost the same as in air, a white 
smoke developing. Soon the potassium becomes 
incrusted with a white material and a black 
material. All the gas becomes absorbed for a while, 
then reappears in the tube t. This designates the 
end of the action. After cooling, we remove the 
mass from the tube. The white portion gives all 
the actions of potash : Strong, bitter taste, easily 
soluble in water, and gas evolution with acid. The 
black portion is not soluble in water ; we separate it 
by filtration. It looks like lamp-black or soot. 
Under the microscope we find it to be of brown color 
and translucent with yellow or brown color. At 
red heat it burns and disappears. If the burning 
be done in an open tube, one end leading by rubber 
tube into lime water, Fig. 34, and air being sucked 
through by means of an aspirator, then the lime 
water will become milky ; the white sediment being 
rhombohedrons. Hence we deduce that the black 
substance is the Y in the lime-gas, because from it 



90 



CHEMISTRY SIMPLIFIED. 



comes lime-gas by combustion. Now we have many 
times observed that charcoal burns and disappears, 
leaving a slight residue of ashes, and we naturally 
will ask : Is there a communion between the black 
1 Y and charcoal ? To satisfy the query we place a 
splinter of charcoal in the tube T, and fresh lime 
water in the test-tube. As the charcoal burns, the 
lime water becomes milky with calcite. Hence we 



FIG. 34. 



Tl 



air 




/JME W/ 




will make the deduction that charcoal is either 
wholly or partly made up of the black substance Y, 
and we resolve the Y into C, which is the first letter 
of the Latin word carbo, the equivalent of the Eng- 
lish charcoal. With characteristic inconsequence 
the English language makes carbon out of carbo. 
Our lime-gas becomes now C n O m ; the calcite becomes 
CaO.C n O m ; potash PO.C n O m , pronounced calcium car- 
bonate, and potassium carbonate. 

The symbol for potassium should be P as we 
adopted it. But here again the English chemists 
are inconsequent in choosing K, which is the first 
letter of the Arab word kali, which means "burnt," 
but was given by the Arab chemist Geber to our 
potash. This word was taken up by all chemists 



THE LESSON OF WOOD ASHES. "91 

with the Arab prefix " al," i. e., alkali, to mean 
any body which shows the essential action of 
potash, these actions being called alkaline actions. 
A solution is said to be " alkaline " when it turns red 
litmus to blue. German and Swedish chemists call 
the metal potassium kalium, English, American, 
and French chemists stick to potassium, but they 
accept the symbol K. 



CHAPTER VI. 
THE LESSON OF COMMON SALT. 

COMMON salt is before us in three forms. 1. 
Rock salt as mined at the mouth of the Mississippi, 
in Canada, and other places in America. It is 
beautifully transparent ; colorless or colored, some- 
times intensely blue. It is found as large, perfect 
cubic crystals, and again as immense, solid, irregu- 
larly shaped masses like ice ; or as fine grained, 
snow-white or dirty gray, or yellow, or red masses. 
It cleaves perfectly in three directions at right 
angles cubical cleavage. It presents slight re- 
sistance to the knife or to the drill. It has a 
strong taste ; is readily dissolved by water. 2. Salt 
from evaporation of salt springs and salt wells, in 
snow-white cubic crystals, which are all hollow on 
the faces. 3. Salt from evaporation of sea-water. 
It is certain that all the deposits of salt, found in 
nearly all geological formations, were at one time 
dissolved in the sea. It is likewise certain that salt 
springs and wells dissolve the rock salt they find in 
the rocks, so that, in the end, our three kinds of salt 
are practically only one kind, sea-salt. Man and 
animals crave salt, their bodies must have salt or 
die. Hence all the languages derived from some 
primitive language have nearly the same name for 

(92) 



THE LESSON OF COMMON SALT. 93 

the substance : Greek : hal, Latin : sal, French : 
sel, German : salz, English : salt. The plant-eating 
animals get some salt with the grass and leaves, 
but it is known that they will travel 100 miles and 
more to get a salt spring or salt-lick, to satisfy the 
craving for salt. Carnivorous animals get their salt 
in the blood of the grass-eaters on which they prey. 
Man takes his from both plants and herbivorous 
animals. Bloody wars have been fought for the 
possession of a salt spring or salt mountain. 

The United States are well supplied with salt, 
and need not go to the evaporation of sea-water. 
Germany is very rich in salt ; exports much to 
other less favored nations. Where the sun's heat 
can be made use of for evaporation, the sea-water 
gives very cheap salt. 

Investigation. Heat does not break up the salt. 
Holding a piece of salt in the flame we see that it 
melts quickly and colors the flame a deep orange- 
yellow. Heating the salt in a glass tube we notice 
decrepitation (enclosed mother liquor escaping ex- 
plosively), then a slight water condensation, then 
melting, then boiling and forming of a white sub- 
limate. No odor, nor gas. 

The sublimate shows itself made up of cubic 
crystals, tastes and acts the same as the original 
salt. Deduction : Salt is volatile without decom- 
position. It may be a simple body as far as heat 
action shows. But not so by its behavior towards elec- 
tricity. We place salt upon a platinum crucible lid, 
the lid being in contact with a sheet of copper and the 



94 CHEMISTRY SIMPLIFIED. 

latter forming the positive pole of the current As 
soon as we bring the other pole wire in contact with 
the salt, the salt melts and an evolution of gas ensues 
accompanied by a very strong and peculiar odor. 
The same odor is produced if we mix salt with blue 
vitriol and heat in closed tube. But let us try our 
two strong agents : Sulfur hydroxyd and potassium 
hydroxyd. 

SaltH-KO.H 2 O+heat=no gas, no apparent effect. 

Salt-|- H 2 O.SO 3 + heat copious evol ution of color- 
less gas possessing a strong, pungent odor, and redden- 
ing blue litmus. Let this gas be called salt-gas. We 
let the gas pass into water : it is absorbed eagerly, 
the solution becoming warm. Looking at this 
phenomenon we cannot deny that it is similar to 
the action of IPO. SO 3 upon calcite, hence that salt 
must be composed of two oxyds 
M S O.N S 0. 

in which neither the metal M nor the non-metal 
N is known to us. With this supposition as a 
guiding thread, we proceed with experiments until 
we shall have established the truth or falsity of the 
conception, and recognized the properties of both 
M and N. 

Salt gas, spirits of salt. If our assumption be true, 
the production of salt gas must occur thus 

M S O.N S + IPO.SO 3 = IPO.N S + M S O.S0 3 

the salt gas must be the hydroxyd of the non-metal 
oxyd N S 0. The gas contains hydrogen. For if we 
expose zinc to it hydrogen is evolved at once. Let 



THE LESSON OF COMMON SALT. 



95 



F be a flask holding about 500 c.c. Let it be fitted 
as in Fig. 35, with funnel, stopper and escape tube, 
all standing on a tripod so that heat may be applied. 
Let C be a bulb tube filled with cotton, to retain 
any particles carried over by the gas. T is a hard- 
glass tube with two perforated stoppers. B a bulb 
tube providing for any liquid mounting back from 
D. t is a test-tube to receive any gas which may be 

FIG. 35. 




generated. Remove stopper /S', introduce 50 grams of 
salt into Fat S, fill funnel with H 2 O.S0 3 and drop 
the latter slowly into F for some time, until upon 
adjusting S' the gas bubbles are all absorbed in the 
water in dish D. Open at S' and introduce zinc at 
Z. Close 8' and adjust tube t. The speed of gen- 
eration of the gas is to be judged by the frothing of 
the salt. T being cold (flame L not having been 
lit) at start, will now warm up : zinc decomposes 



96 CHEMISTRY SIMPLIFIED. 

gas at ordinary temperature, the combination pro- 
duces heat. Prove the gas in test-tube is hydrogen 
by showing it inflammable. At Z a new body has 
been formed which is fusible, proven by means of 
lamp L. By withdrawing it from the tube it is found 
to be soluble in water. (Prove solution by testing 
with potash and also with KO.H 2 0), therefore this 
substance cannot be zinc oxyd for this latter is neither 
fusible nor soluble in water; it must be a combination 
of zinc with the unknown N. Acting upon it with 
IPO. SO 3 the pungent gas forms same as with the 
salt. Nevertheless the combination may contain 
oxygen. As we know the great avidity of potassium 
for oxygen, let us act as follows : We bring into a 
test-tube a part of the unknown compound ZnN s O ; 
we fill the tube with hydrogen, excluding thus any 
air ; we then add a piece of bright, carefully cleaned 
potassium and apply heat, hydrogen still passing in. 
The action would have to be thus : 

ZnN s O + 2K + heat = Zn + N S K + KO 

or = ZnKN 8 + KO 
or with 3K = ZnK-f-N s K + KO 

It will evidently not matter which of the reactions 
ensues, or whether all three occur at the same time. 
The essential point is the forming of KO ; because 
if water be now brought into contact with the mass, 
EPO.KO will be formed arid will cause the change 
in litmus from red to blue. The experiment will 
give true information only, if ZnN 8 be in excess, 
for otherwise K would be left and in contact with 



THE LESSON OF COMMON SALT. 97 

water would give the hydroxyd -f- hydrogen. The 
experiment must be made with much judicious care, 
and will prove that KO is not formed and, hence, 
that oxygen is not present in the compound and there- 
fore not present in the salt gas. Our preliminary sup- 
position was wrong : Salt gas must be N S H. How are 
we to set free N s ? In the case of the limestone gas we 
were successful with potassium because the C (carbon) 
does not combine with potassium ; but in this in- 
stance, when we find the unknown N s to combine 
with zinc, it seems more than likely that it will 
combine with potassium also. However, let the 
trial be made. The apparatus, Fig. 35, will be 
quite suitable. We simply substitute a piece of 
potassium at Z in place of zinc. We note a strong 
action even at ordinary temperature, a white sub- 
stance forming and hydrogen evolving. The white 
substance forms cubes and octahedrons, it tastes like 
common salt ; hence we conclude that the metal 
M in salt must be similar in its nature to K. Whilst 
this is welcome information, it is not what we are 
looking for. The unknown is not set free. 

Another train of thought is needed ; we know the 
unknown to be a hydrogen combination. Now the 
metals having failed us, let us try the non-metals. 
Of these we know oxygen, azote and sulfur, and of 
these oxygen seems the most active. We reason 
along the scheme 



Mixing oxygen and salt gas at ordinary tempera- 
7 



98 



CHEMISTRY SIMPLIFIED. 



ture has no effect as seen in this cylinder, which 
holds the mixture ; therefore let the mixture, one 
volume of each, be passed through the glass tube T 
(Fig. 36) and let asbestus A (mineral wool) partly 
fill the tube. The asbestus being brought up to 
redness, the gas mixture slowly passes through it 
in measure as the cylinder C f is raised and the 
cylinder C" is lowered. While C fills with mercury 
the pipette P fills with a gas of pale-green color. 

FIG. 36. 




This gas we shall hereafter name chlorine, (Cl.) from 
Greek chloros = green. For consistency's sake the 
name should be chlorium as hydrogenium, ferrum, 
stannum, potassium. (The great chemist, Berzelius, 
never gave up his belief that this chlorine was a 
compound and not an element, that it does contain 
oxygen, but that we are not able to separate the 
two. The demonstration we have gone through 
above leaves very little doubt that the salt gas and 
hence chlorine do not contain oxygen.) 

Chlorine, physical properties. A green gas of 



THE LESSON OF COMMON SALT. 99 

peculiar, very strong odor ; offensive to the mucus 
membrane, producing ulceration upon the latter 
down into the bronchial tubes and capillaries of the 
lungs, painful coughing ; must be careful not to 
breathe the gas ; if necessity compels to stay in a 
place filled partly with chlorine must keep mouth 
and nose covered with a wet sponge. The gas is 
very heavy. It is 35.5 times heavier than hydrogen, 
2.45 times heavier than air, and 2.216 times heavier 
than oxygen. One litre of the gas at C. and 
760 mm. mercury pressure weighs 3.178 grams. 
1 c.c. equals 0.003178 grams, roundly 3 milligrams. 
The gas dissolves somewhat in water. The maxi- 
mum solubility lies at 9.5 C., and corresponds to 
2.75 times the volume of the water. Hence 10 c.c. 
of water will absorb at best 27.5 c.c. of the gas. 
But since 1 c.c. of gas weighs three milligrams, 
the 27.5 c.c. will weigh 82.5 milligrams, or 0.0825 
grams, and hence in weight per cent. 0.825. It is 
well to remember that the most concentrated water 
solution of chlorine does not contain quite one per 
cent, of chlorine ; at 30 C. only 1.75 volumes 
equals 0.525 weight per cent. At boiling heat the 
chlorine is completely driven from its solution. 

Chlorine gas condenses into a mobile yellow 
liquid under a pressure of 8.5 atmospheres (127.5 
pounds per square inch). 

Preparation of chlorine. In the practical prepara- 
tion of chlorine it is more advantageous to supply 
the oxygen in combined form, as a superoxyd, an 
oxyd which contains more oxygen than it can hold 



100 CHEMISTRY SIMPLIFIED. 

firmly. Nature furnishes us with such in the so- 
called soft manganese ore MnO 2 , the pyrolusite of 
mineralogists. The salt-gas acts upon this oxyd 
even at ordinary temperature ; very energetically at 
about 60 C.; thus 

MnO 2 + 4HC1 (salt-gas) + heat == MnCl 2 + 
2H 2 + 2CL 

Only one-half of the chlorine contained in the salt- 
gas appears as free chlorine, the other half forming, 
with the metal manganese, a pale, rose-colored salt 
manganese clilorid, MnCl 2 . 

Neither is it convenient nor economical to act 
with the salt-gas upon the superoxyd. A solution 
of the gas in water is much better adapted to this 
purpose, the best concentration is 20 per cent. How 
to make such a solution will be explained in the 
next paragraph below. The most suitable apparatus 
is the Koenig generator, represented in Fig. 37. G 
is the generating tube drawn out at lower end 0, 
where a stout rubber tube R is wired onto it. The 
tube R has at its other end a bent glass spout P, 
which rests upon the edge of the waste vessel W. 
The upper end of G is somewhat restricted, and a 
glass stopper S is ground into the restriction. This 
stopper is fused to the funnel tube F, the latter 
carries a stop-cock and a receiving bowl for the salt- 
gas solution. L is the outlet for the chlorine. Jis 
a wider glass tube, fused onto 6r, so as to form a 
complete jacket around the latter. The tubulature 
E serves to fill this jacket either in part or entirely 



THE LESSON OF COMMON SALT. 
FIG. 37. 



101 




8 



$y r// YA v- , y r^-- 





KOENlG'S GENERATOR. 



102 CHEMISTRY SIMPLIFIED. 

with water whilst a glass tube T encircles the jacket 
obliquely, and is fused into the jacket at both ends. 
This small encircling tube is full of water, and, be- 
ing heated by the small flame from a glass tube or 
a Bunsen burner, brings up a circulation and raises 
the temperature in /-to any desired point. Upon 
the porcelain false bottom I) rests the manganese 
superoxyd in small pieces, about pea-size. The 
column of MnO 2 should not be over 3 inches high. 
The apparatus is held by the brackets B, B, B, 
against the wooden stand Q, the latter being sup- 
ported by the bottom plate N. We start by filling 
water into G until the tube R is full and the water- 
level in the spout P is even with the level at the 
false bottom D. Then we heat the jacket to 60 C., 
and thereupon drop the salt-gas solution at the rate 
of one drop a second. There will then be a steady 
current of chlorine gas issuing through, whilst an 
equally constant discharge of the by-product, i. e., 
MnCl 2 will discharge itself at P into the waste 
vessel Wj provided the bowl of the funnel is kept re- 
plenished. If a stopping be desirable, simply turn 
the stop-cock in F. The gas will not be quite pure. 
It will be mixed with some liquid particles and also 
with some salt-gas. Hence we conduct it through 
a wash bottle containing some water, then through 
another such containing IPO. SO 3 ; in the latter the 
aqueous vapor will be removed, in the former the 
other admixtures. Of course, whenever dry gas is 
not required, the second wash bottle may be omitted. 
You will take notice that the rubber tube R forms 



THE LESSON OF COMMON SALT. 



108 



a trap against the escape of the gas downward, 
whilst the narrow funnel tube keeps the gas from 
escaping upwards. But it stands to reason that if a 
resistance be placed at L of greater weight than the 
column of liquid in either F or R, then the gas 
escapes through them, they forming the natural 
safety valve. 

A generator may be rigged more simply and 

FIG. 38. 




cheaply. A, Fig. 38, is a small flask, t is a glass 
tube, F a funnel connected with t by a short rub- 
ber tube and clamp C, t f tube for escaping gas ; 
/ a i" rubber tube, W a beaker glass in which 
stands a large test-tube fitted with rubber stopper 
/S', and partly filled either with water or with 
IPO. SO 3 serving as wash bottle. The manganese 
superoxyd is placed in A at M, F is filled with salt- 



104 CHEMISTRY SIMPLIFIED. 

gas solution. The apparatus is ready for use. In a 
measure, however, as MnCl 2 accumulates in A, the 
evolution of chlorine becomes slower, a steady 
stream cannot be maintained by it, except for a very 
short time. I worked for twenty-five years with 
such an apparatus, until I made the more perfect 
one described above. 

Chemical properties of chlorine. Chlorine is a 
most powerful agent at ordinary temperature, when 
oxygen is almost inert. It attacks all the metals, 
and in presence of water dissolves most of them : 
Gold, platinum, tin, copper, iron, zinc, but not so 
lead, silver, mercury. 

Upon oxyds, it acts thus : 

CuO -f 2C1 + heat = CuCP + 
MnO 2 + 2C1 + heat - MnCl 2 + 20 
Chlorine acts upon all coloring matters taken 
from plants, such as litmus, indigo, the red cab- 
bage, and many others, in such a way that the 
color vanishes, bleaches. 

Upon the hydroxyds of potassium and calcium, 
chlorine acts as follows : 

2CaO.H 2 + 4C1 + water - CaCl 2 + CaO.Cl'O + 

2H 2 0. 

The milk of lime becomes dissolved to a clear 
liquid. If the dry slaked lime flour of lime be 
exposed to chlorine the same action takes place, but 
the resulting product is a slightly pasty solid, and 
is called bleaching lime; is soluble in water, and is 
used in large quantities by the bleachers and dyers 



THE LESSON OF COMMON SALT. 105 

of yarn and cloth. The compound CaCl 2 does not 
bleach, only the compound CaO.CPO, and in this 
only the oxyd CPO is the bleaching factor. 

Upon potassium hydrate the action is parallel, 
thus : 

2K X O.H 2 + 3C1 = KC1 + K X O.CPO + 2H 2 O. 
You pass the chlorine gas into the solution so long 
as it is freely absorbed. The result is a bleaching 
solution. But if we boil this solution for some 
time, it begins to throw out scaly crystals, white or 
colorless. Let these crystals be separated from the 
liquid, then dried, and then heated in a closed 
glass tube, when they will be seen to melt easily 
with strong evolution of gas. The gas proves to be 
pure oxygen. (Explode it with 2 volumes of hydro- 
gen.) When no more gas is given out the residue 
contains only potassium and chlorine, is KC1. The 
crystals themselves are produced from the boiling 
solution by the following reaction : 

6K X O + 6C1 + water + boiling heat = 4KC1 + 

K X O.CP0 5 , 
and when the crystals are decomposed by heat : 

K X O.CP0 5 + heat = 2KC1 + O 6 . 
The crystals represent a compound of the metallic 
oxyd K X with the non-metallic super oxyd C1 2 5 . 
The latter is unstable, overloaded, hence heat breaks 
it up easily, and as we have seen above that chlorine 
drives oxygen from the oxyds, the final result must 
be KC1 -f 6 oxygen. The crystals shall be known as 
potassium chlorate. It is a very valuable compound 



106 CHEMISTRY SIMPLIFIED. 

to us, because we can obtain by it at any time 
quantities of the purest oxygen. 

Manufacturing process for potassium chlorate. The 
potassium hydrate is relatively costly, the cal- 
cium hydroxyd very cheap, KC1 is also cheap (a 
natural mineral sylvite). On passing chlorine gas 
into water in which have been slaked 3 equiva- 
lents of calcium oxyd (burnt lime) at boiling heat 
until the liquid has become clear, we have a solu- 
tion of calcium chlorate (easily soluble). We bring 
into it one equivalent of KC1 and potassium chlorate 
falls out in crystals (because it is not readily soluble 
in water). 

Composition of salt gas. We found the gas com- 
posed of hydrogen and chlorine. Now we have to es- 
tablish their ratio in the compound. If we pass one 
volume of salt gas over heated zinc repeatedly, in the 
apparatus Fig. 36, we find that the volume of the gas 
becomes reduced to one-half. Chlorine unites with 
zinc, becomes solid so to speak, the remainder is pure 
hydrogen. Hence we deduce : Salt gas is composed 
of equal volumes of hydrogen and chlorine ex- 
pressed by the symbol HC1. If we fill into a cylinder 
one volume of hydrogen and one volume of chlor- 
ine and let the mixture stand in the diffused day- 
light for some days, the volume does not change, 
but the two gases shall have become united to HC1. 
We can prove this by introducing a few c.c. of 
water ; the gas is all absorbed by the water ; 
chlorine would have only been slightly absorbed, 
hydrogen not at all. Should we expose the mixture 



THE LESSON OF COMMON SALT. 107 

of H -|- Cl to the direct sunlight, the union would 
follow at once with explosive energy. It is import- 
ant to note that the volume of the compound is 
equal to the sum of the volumes of the components ; 
neither contraction nor expansion taking place. This 
is a law for all unions of gaseous bodies in equal volumes. 
The name for the compound HC1 shall be hydrogen 
chlorid, and all combinations of metals with chlor- 
ine shall be named chlorids, as we name the oxygen 
compounds oxyds. Some chemists speak and write 
chlorides, oxides; it is quite immaterial which you 
use, but choosing one you should stick to ib; the 
shorter sound would seem to be preferable. 

Properties of hydrogen chlorid : A colorless gas at 
ordinary temperature, powerfully pungent odor, 
exciting the mucous membrane. Near the freezing- 
point of water at +4.4 C. the gas becomes a liquid 
under a pressure of 30.67 atmospheres or 460 Ibs. 
per square inch. At a temperature of 73.3 C. 
only a pressure of 27 pounds is needed. Liquid 
HC1 is mobile and colorless, heavier than water. 
No practical use has been found for it. The specific 
gravity of the hydrogen chlorid gas is 1.255 (air = 
1) ; 1 c.c. of it weighs 0.00163 gram, just about one- 
half that of chlorine. By weight the gas contains 
97.26 of chlorine, 2.74 of hydrogen. 1 volume of 
water can absorb 500 volumes of HC1 gas at the 
freezing-point; at 20 C. (common temperature) water 
absorbs 440 volumes of the gas. The absorption of 
the gas produces heat. This would lead us to 
think that there must be a chemical affinity 



108 CHEMISTRY SIMPLIFIED. 

between HC1 and IPO ; that there must be hy- 
drates. In fact it is quite probable that two such 
exist. For, if a concentrated solution of HC1 in 
water be heated (a thermometer registering the tem- 
perature), it will give out for some time only 
moist HC1 gas. The temperature having risen to 
100 C., water passes over with HC1 and a very 
concentrated solution condenses having specific 
gravity 1.19. As the temperature rises the distil- 
late becomes more watery until the temperature 
reaches 111 C., at which it remains constant whilst 
a solution distills over possessing specific gravity 
1.104. This solution contains 21 per cent. HC1 and 
79 per cent, of water, nearly the hydrate 2HC1 -f- 
15H 2 0. A second hydrate is HC1 + 6H 2 0. 

Hydrochloric acid Muriatic acid HC1 -f- water. 
These names are given to the water solution of HC1. 
We speak of highly concentrated acid, concentrated 
acid, dilute acid, very dilute acid. 

Sp. gr. Per cent. HC1 

Highest concentrated, 1.200 40.77 

Highly concentrated, 1.1802 36.29 

Strong acid, 1.151 30.58 

Medium, 1.072 14.68 

Dilute, 1.042 8.56 

Very dilute, 1.006 1.12 

Problem : Construct with these data a curve whose 

ordinates shall be the percentage and the abscissae, 

the specific gravities. 

Preparation and manufacture. Small quantities 
are made by distillation in glass flasks or glass re.- 



THE LESSON OF COMMON SALT. 



109 



torts. On a commercial or manufacturing scale, 
cast-iron vessels are used, either cylinders, or else 
flat pans standing within a brick furnace. Cast 
iron is not attacked by concentrated sulfuric acid nor 
by HC1, but is energetically attacked by a solution 
of HC1 in water. Such properties render the iron 
vessels fit. Concentrated sulfuric acid acts violently 
upon salt even at ordinary temperature ; the mass 

FIG. 39. 




threatens to froth over. An addition of water gives 
relief. Our prescription is : For every ten grams 
of salt take 9.6 c.c. of concentrated IPO. SO 3 and 
5.5 c.c. of water. Mix the two liquids in a beaker- 
glass, fill from it the basin B (Fig. 39) of the funnel ; 
place the salt in the flask F ; make connection 
with the Wulf bottle W by tube t which passes 



110 CHEMISTRY SIMPLIFIED. 

under the level of the wash water. The tube t' also 
passes under the surface level and is open at the 
top ; t' is the safety valve of the apparatus, because 
air will pass into it whenever a partial vacuum is 
brought about ; t" leads into the absorption flask A 
which contains as much water by weight as the salt 
taken. The student takes 50 grams of salt and 
places 50 c.c. of water in the absorption bottle. 
The stoppers S, 8, S must be of rubber. The flask 
F must hold 500 c.c. All the acid may be put in 
at once, and then heat applied gently at first, and 
regulated to keep up a steady evolution. When the 
gas stops, finally, the operation is terminated and 
you let air in through the funnel tube. In removing 
the flame, it will be seen that the liquid in F solidi- 
fies, by degrees, as it cools down. Remelt it and 
pour it out on a clean stone or iron surface. Let it 
be named "crude salt cake." It must, evidently, 
be the vitriol of the unknown metal M, and will be 
taken up presently. 

Action of hydrochloric acid. The water solution of 
HC1 is nearly as powerful an agent as the gas itself, 
and for most purposes can be employed in its stead. 
Because the metallic chlorids are more readily solu- 
ble in water than the vitriols, excepting the chlorids 
of silver, lead, and mercury; therefore, we shall use 
.it in preference to the sulfuric acid, whenever we 
desire to dissolve bodies which are not soluble in 
water. As, for instance, we wish to generate lime- 
gas. The calcium vitriol is very insoluble, and we 
have heretofore used acetic acid for the decomposi- 



THE LESSON OF COMMON SALT. Ill 

tion. Instead we shall use hydrochloric acid here- 
after ; the calcium chlorid is much more soluble 
than the vitriol, in fact, it will dissolve by merely 
allowing it to stand uncovered in ordinary air which 
is always more or less moist. Hence, we can em- 
ploy, to advantage, this chlorid in place of concen- 
trated sulfuric acid for the drying of gases. Being a 
porous solid, the calcium chlorid offers more surface 
to the gas than an equal volume of liquid sulfuric 
acid. 

The chemical actions may be represented thus : If 
R stands for a metal, whose chlorid is soluble in 
water : 

R -h water + HC1 solution = RC1 solution -f- H ; 
and on oxyds 

RO + water + 2HC1 solution RC1 2 solution + 

H 2 0; 

if, however, silver vitriol solution be brought to- 
gether with hydrochloric acid, a white, curdy pre- 
cipitate falls out at once, AgCl, 

Ag 2 O.S0 3 + water + 2HC1 solution = 2AgCl + 

H 2 O.S0 3 solution 

because the silver chlorid is insoluble in water. 
Thus we can prove the presence or absence of silver 
in any unknown solution by adding to it a drop of 
hydrochloric acid ; if a curdy cloudiness follows, 
then silver is present. 

Pure hydrochloric acid is quite colorless. The 
yellow color of the commercial muriatic acid is 
owing to some iron chlorid coming from the iron ves- 



112 



CHEMISTRY SIMPLIFIED. 



sels and iron oxyd in the crude salt. The strength of 
commercial acid is mostly indicated in degrees on the 
Beaume hydrometer, instead of by the specific gravity. 
Such an instrument (Fig. 40) is correct if it sinks 
in pure water at 17 C. to the zero mark. Zero is 
therefore equal to specific gravity 1.000. In a 15 
per cent, solution of common salt (salt = 15, water 
= 85) the spindle must sink to the mark 15; the 
degrees being equal divisions. Very concentrated 



FIG. 40. 



o i: \.ooo 



FIG. 41. 





hydrochloric acid is said to be 22 Be. (specific 
gravity 1.176). There is, of course, a second spindle 
for liquids lighter than water. In this instrument 
(Fig. 41) the zero point is near the bulb, the weight 
in the bulb, being so chosen that the spindle sinks 
in a solution of 10 per cent, salt (salt 1, water 
9) to the zero point, whilst in pure water it sinks to 



THE LESSOX OP COMMON SALT. 113 

division 10 ; the same unit (found by dividing the 
space between and 10 into 10 equal parts) is then 
drawn on the scale upward to the limit of the spindle. 
Kerosene, gasoline and other coal-oil products are 
gauged in the United States by degrees Be\ Alco- 
hol is gauged by the hydrometer of Tralles. It is not 
sufficient to say that a liquid stands at so many de- 
grees Be., it must be said whether reference is had 
to a liquid lighter or heavier than water, which can 
be done by the signs +, , or by letters : 1. w ; 
h. w. Thus the light gasoline for gas-making is 
87 Ed, and the concentrated sulfuric acid is 
+ 66 Be'. Hydrochloric acid can be shipped only 
in glass vessels ; the sulfuric acid can be transported 
in iron tanks. The glass vessels large, spherical, 
holding 5 to 10 gallons, and being packed with 
straw into wooden boxes are known as carboys. 
For manufacture on a large scale get information 
in Lunge's Manufacture of Soda Ash (recent) or in 
Ure's Dictionary (old). 

Claude salt cake, discovery of the metal sodium. 
Let some of the crude cake, obtained by action of 
H 2 S0 4 on salt, be heated in a porcelain crucible 
over an open flame. Dense white fumes are soon 
seen to arise. The fumes are now diagnosed by us 
as probably being sulfur trioxyd, oil of vitriol. As 
the vapors escape, the melting-point of the cake 
rises. Finally, when no further fumes come off, 
the stuff appears dry at a red heat. At yellow heat 
it melts again, and remains so without yielding any 
more fumes or gas. Reason for the fumes : The 
8 



114 CHEMISTRY SIMPLIFIED. 

crude salt cake is M S O.S0 3 .H 2 O.S0 3 , a so-called 
acid vitriol, quite constant at low heat, but break- 
ing up at high heat into M S O.S0 3 + JPO + SO 3 . 
The final remnant is M S O.S0 3 =salt cake refined. 
We had added in the recipe given just twice as 
much sulfuric acid as is needed, and did this know- 
ingly, for otherwise we could not have completely 
decomposed the salt in a glass flask ; the stuff would 
not have liquefied ; the flask probably broken. Salt 
cake dissolves in cold water easily ; this property 
distinguishes it from the potassium vitriol and the 
calcium vitriol. In order to isolate the metal let 
us make use of our experience with charcoal car- 
bon. We mix the powdered salt cake with powdered 
charcoal, cover the crucible, and expose it in a char- 
coal or gasoline furnace to strong red heat. We 
may do it in a hard glass tube first. Result is a 
dark-colored mass ; metallic particles are not visible, 
and if we bring it together with water there is no 
evolution of gas, such as potassium produced. 
However, it dissolves in water, leaving charcoal 
powder, which we separate by filtration, and test, 
after thorough washing, by burning ; as it quite 
disappears (leaving only trace of ash), we are correct 
in calling it charcoal. The filtered liquid has a 
brown or red-brown color ; it gives alkaline reaction 
to litmus ; has a strong taste. With hydrochloric 
acid, gives off gas smelling of rotten eggs, and if 
this gas be passed through a glass tube heated to 
redness a sublimate of sulfur forms. If bright cop- 
per or silver be brought together with the liquid, 



THE LESSON OF COMMON SALT. 115 

the metal turns black, and if these strips of black- 
ened metal be heated in an open tube we get the 
smell of SO 2 . If boiled with finely-divided copper 
oxyd, the liquid becomes decolorized and does not 
any more blacken the metallic copper, whilst it' 
gives still a strong alkaline reaction. From all 
these observed facts we draw the following deduc- 
tions : 

1. The action of charcoal must have been, sym- 
bolically, thus 

M S O.S0 3 + nC = M S S + 4CO -f n-4C ; 
the vitriol was converted into a sulfid. 

2. The action of metallic copper and metallic 
silver was probably 

M S S + nH 2 + Cu = CuS (black) + M S O.H 2 
(alkaline) + (n-1) IPO. 

3. The action of copper oxyd was probably 

M S S + CuO + nH 2 = CuS + M S O.H 2 (alkaline) 

+ (n-l)H 2 0. 

The hydroxyd of the unknown metal is easily solu- 
ble in water, and being strongly basic alkaline 
it must be akin to potassium. We evaporate the 
liquid from (3) to a white solid, which afterwards 
fuses and then goes off in white fumes, just like potas- 
sium hydroxyd. We act upon this material with 
zinc, and by evolution of hydrogen prove it to be 
hydroxyd. Next we act upon it with the electric 
current ; gas at positive pole ; metallic globules and 
gas at negative pole ; and by using mercury as the 
negative pole we obtain a solid amalgam, from 



1*16 CHEMISTRY SIMPLIFIED. 

which the metal M may be separated by distillation 
in a current of hydrogen gas. If we act upon the 
hydroxyd with charcoal-loaded iron chips at a yel- 
low heat, the metal will distil over, same as potas- 
sium, but the flame issuing from the retort burns 
with ^yellow color (distinction from potassium, purple 
flame). In the neck of the retort we find a black 
mass which acts like that found in the distillation 
of potassium. This mass is mixed with the con- 
densed metal. 

Properties of the metal sodium. The name sodium. 
is given to the metal by English, French, and Amer- 
ican chemists. Germans and all others give it the 
name natrium, using the first two letters as the sym- 
bol, Na, which stands for the chemical unit of 
mass. English, Americans, French use the same 
s}^mbol, hence sodium, Na. Natrium is derived 
from Greek nitron ; Egyptian and Hebrew neter, a 
name given by those people to the crusts forming 
around the desert lakelets, and which was found to 
have similar cleansing properties to potash. It is 
now known as soda ash. Whence the word soda 
comes is not known, nor what it means. Perhaps 
from the Latin soldere, English solder, since this 
material may have been confounded with borax, 
such mixtures being useful in joining metal pieces 
by heat. (Author's notion.) 

The metal sodium is soft like wax at ordinary 
temperature, can be hammered at freezing-point, 
becomes liquid at about 95 C. (melting-point 
is higher than that of potassium 65 C.). In color 



THE LESSON OF COMMON SALT. 117 

it is silver-white like potassium ; the fresh-cut sur- 
face becomes rapidly dull from oxydation. Sodium 
becomes vapor at red heat, and this vapor has a 
purplish color potassium green. Specific gravity 
at 10 C. is 0.974 (water == 1). Coefficient of ex- 
pansion 0.000073, larger than that of any other 
metal except potassium (0.000083). It conducts 
heat and electric waves well, about 37 (silver = 
100). Its specific heat or heat capacity is 0.2934. 
Its heat of fusion is 0.73 Cal. 

Chemical properties of 'the metal sodium. Thrown 
upon water it sets up an evolution of gas and melts 
into a globule which is covered by a gray film. 
The gas does not ignite, unless the water be heated 
to about 60 C., or unless the water be thickened 
with gum arabic or glycerine. We deduce from 
this action that sodium has not as much affinity 
or attractive tendency for oxygen, as potassium ; 
hence less heat is generated. If the globule be left 
on the water until the gas evolution stops, the 
globule flattens out suddenly and an explosion en- 
sues. If the globule be taken from water when gas 
stops, it is found composed wholly of oxyd. (The 
explosion is explained by the sudden rise of steam 
when the oxyd becomes hydroxyd.) 

If the metal be heated in oxygen gas, or in a 
mixture of air and oxygen, a yellow substance re- 
sults which is the superoxyd of sodium; on cooling it 
turns white. It dissolves in water without decom- 
position, and can be melted without decomposition. 
If heated with copper, lead, zinc or tin the sodium 



118 CHEMISTRY SIMPLIFIED. 

superoxyd changes these metals into oxyds. With 
HC1 it gives NaCl + H 2 + 0. If this action be 
done in water solution, oxygen does not escape ; the 
water then contains sodium chlorid, NaCl, and hy- 
drogen superoxyd (also called peroxyd), H 2 2 or 
HO ; we assume therefore that the sodium peroxyd 
must have a similar composition to the hydrogen 
peroxyd, namely, Na 2 2 , the reaction will be 
Na 2 2 + 2HC1 + water = 2NaCl + H 2 2 + water. 
This solution of hydrogen peroxyd is a powerful 
oxydizing agent and is much used both in labor- 
atory work and on a large scale for manufacturing 
purposes. 

If the superoxyd has the composition Na 2 O 2 then 
the oxyd must be Na 2 0. We get this by fusing 
together the hydroxyd with the metal in proper 
proportion. It is a gray substance, and of no spec- 
ial application. It attracts moisture from the air 
and becomes hydroxyd. 



CHAPTER VII. 
THE STORY OF SODA ASH AND LEBLANC. 

WHEN in the early years of the past century Na- 
poleon closed all the harbors of Continental Europe 
to English and American ships, in order to destroy 
the commerce of England, as he could not destroy 
its navy, there arose in Continental Europe a scar- 
city of potash, since the supply had nearly all come 
from the American colonies. To ease the demand 
for this article, as well as to spite England, Napo- 
leon offered a prize of 100,000 francs, 20,000 dol- 
lars, for the discovery of a substitute for potash. 
This prize was won and awarded to the French 
chemist Leblanc, who proposed a process by which 
common salt can be turned into a body which may 
be substituted for potash in most technical applica- 
tions, a process which held its own for 80 years and 
is only now giving way slowly to better meth- 
ods. (See Solvay process at end of chap. XL) All 
the reactions were known to chemists at the time 
but one, the replacing of copper oxyd by a cheaper 
compound. Leblanc found that limestone, or oyster 
shells, or chalk could replace the copper oxyd, if 
the action takes place at red heat. To wit : 

Na 2 S + 2CaO.CO 2 + red heat = Na 2 O.C0 2 + 

CaO.CaS+ CO 2 . 

(119) 



120 CHEMISTRY SIMPLIFIED. 

Na 2 O.C0 2 is easily soluble in water; CaO.CaS (cal- 
cium oxysulfid) is insoluble in water, and Na 2 O.C0 2 
is the practical substitute for K 2 O.CO 2 (potash). 
The entire run from salt to soda ash is represented 
in the following symbolic scheme : 

(1) 2NaCl (salt) + 2H 2 O.S0 3 + heat = 2HC1 + 
Na 2 O.S0 3 .H 2 S0 3 . 

(2) Na 2 O.S0 3 .H 2 O.S0 3 + heat = Na 2 O.S0 3 (salt 
cake) + SO 3 + H 2 0. 

(3) Na 2 O.S0 3 + 4C + 2CaO.C0 2 (chalk) + yel- 
low heat == Na 8 O.C0 9 + CaO.CaS + CO 2 -f 4CO 
(inflammable gas). 

(4) Na 3 O.CO 8 + CaO.CaS + water + heat - 
CaO.CaS (residue) + Na 2 O.C0 2 (solution). 

(5) Na a O.CO a (solution) -f evaporation = Na 2 O. 
CO 2 , soda ash. 

The soda ash produced in this way is not pure : 
The carbonate predominates, but mixed with it we 
find Na 2 O.H a O,Na s S and other impurities. It can 
be purified ; not necessary for most of the applica- 
tions, such as soap-making. A factory in which 
soda ash is produced goes by the name of alkali 
works. It is usually divided into several depart- 
ments, located in separate buildings. (a) Acid 
works where the sulfuric acid is made, (b) Salt- 
cake works, (c) Black ash smelter and extractor, 
(d) White ash works, (e) Bleaching-lime works, 
where the hydrochloric acid is converted into chlor- 
ine and the latter is absorbed by the dry slaked 
lime. 



THE LESSON OF SODA ASK AND LEBLANC. 121 

SODA ASH SODIUM CARBONATE, SAL SODA, 

BAKING SODA. 

When the liquid resulting from action (4) (see 
above) is evaporated to dry ness and then fired to 
red heat, the product bears the name crude white 
soda ash. If the same liquid is however only evap- 
orated or boiled down to a certain point and is then 
allowed to cool slowly, large crystals will form. 
These are Na 2 O.C0 2 + 10H 2 and go by the name 
sal soda (salt of soda). The impurities remain in 
the mother liquor. If they be exposed on wicker 
hurdles in an exposed space into which lime gas is 
conducted from the top of a lime kiln, then they 
will pass into a fine granular white sandy material 
whilst water runs away from them. The white 
powder goes under name of baking soda, bicarbonate 
of soda. The action is thus : 
Na 2 O.CO 2 + 10H 2 O-hC0 2 (lime gas) = Na 2 O.C0 2 .- 

# 2 0.<70 2 + 9H 2 0. 

The bicarbonate is slightly soluble in cold water, and 
at the boiling temperature it breaks up into Na 2 0.- 
CO 2 + CO 2 -f H 2 0. If therefore this material be 
mixed with flour and the resulting dough is put 
into an oven we will just get that same decomposi- 
tion, the escaping lime gas causing the raising of 
the dough. But the bread must taste bitter from 
the sodium carbonate which remains. In the so- 
called baking powders, the baking soda forms only 
one ingredient, the other being an acid salt which 
not only decomposes the carbonate but also removes 
the bitter taste. 



122 CHEMISTRY SIMPLIFIED. 

Caustic soda or concentrated lye, of the manufac- 
turers is made by decomposing a 10 per cent, solu- 
tion of soda ash with one equivalent of slaked lime, 
the same process we considered under caustic potash. 
The resulting solution of the sodium hydrate is 
evaporated, fused and cast into sheet-iron drums, or 
cans, for smaller quantities, or into one-pound balls, 
which latter are then dipped into molten rosin. 
The film of rosin keeps the material from attracting 
moisture from the air and thus liquefying. The 
farmers' wives now buy these lye balls for their soap- 
making instead of bothering with the wood ashes. 
The man who had the idea of the rosin film made a 
fortune from the patent rights. 

Certain sea plants growing in the tide levels of 
France and England, called kelp in Wales, and 
varec in France leave an ash .which is largely made 
up of sodium carbonate, the plant's energy trans- 
forming the salt into the soda, 



CHAPTER VIII. 

A CHAPTER ON THEORIES; ON COMBINING 
WEIGHTS, ATOMIC WEIGHTS AND VALENCES. 

THE existence of such bodies as chlorids, especially 
sodium chlorid, containing no oxygen, and yet so 
much alike to oxygen salts, leads us to thinking. 
Let us compare hydrogen chlorid, HC1 and sulfuric 
acid, IPO. SO 3 . As the symbols stand written, 
two do not seem at all comparable. But supposing 
we change the grouping of the elements in the sul- 
furic acid thus : 

H 2 O.S0 3 H 2 .S0 4 , 
then at first glance we notice the resemblance, 

H.C1 H 2 .S0 4 , 
and more so still if we place the SO 4 into a bracket, 

H(C1) H 2 (S0 4 ). 

We have no knowledge of an oxyd, SO 4 ; we only 
know SO 2 ,, SO 3 , S 2 3 , S 2 4 ; yet without a great 
wrench we can imagine that the very moment when 
the two oxyds, H 2 and SO 3 , are brought together, 
a rearrangement of the elementary particles comes 
ab.out harmoniously, quite imperceptible to the eye. 
As soon as we disturb the harmony by trying to 
remove the hydrogen, then disarrangement, a break- 
up takes place. But if we accept the reality of 
(123) 



124 CHEMISTRY SIMPLIFIED. 

this improvable state of things, then the schism in 
the fundamental chemical phenomena gives way to 
resolved uniformity. The acids become then combi- 
nations of hydrogen with a non-metallic radical; the 
radical can be either one non-metallic element or a 
group of such elements. In hydrochloric acid, 
chlorine is the radical, in sulfuric acid the group 
(SO 4 ) is the radical. The word radical is the adjec- 
tive of the Latin noun radix = root ; from the 
radical, root, arises the stem the sourness, the 
acidity. When a metal acts upon an acid, hydro- 
gen escapes. According to the new light we cir- 
cumscribe this by saying the metal takes the place 
of the hydrogen : 

H(C1) + K = K(C1) + H 

Why does it do so? Because potassium has a 
stronger affinity for the radical chlorine than hy- 
drogen, and this stronger affinity is made percepti- 
ble by the greater quantity of heat which is set free 
by the union of the two. If Cal. = the unit of heat, 
then 

H + Cl = HC1 + nCal. 

K + Cl = KC1 + n'Cal. 

n'>n. 

Metals such as lead, copper, silver, gold do not act 
upon the dilute acids; they are not dissolved by 
them, because their heat of formation is very small 
and requires a heat-addition from the external con- 
ditions. Thus we can establish a series of the metals 
in which potassium will occupy the one flank and 



A CHAPTER ON THEORIES. 125 

gold the other : K., Na., Ca., Mn., Zn., Fe., Sn. } Pb., 
Cu., H., Ag, AU. 

If we designate K as -f , then Na will be negative 
in regard to K, but positive in regard to Ca, and 
each metal in the same way positive towards its 
neighbor on the right, negative towards the one on 
the left. Equally if we place two pieces of sheet 
metal upon one another with a moist piece of felt 
between, for example, zinc and copper, an electric 
tension will show itself between them. Galvani 
observed this 120 years ago, and his name is at- 
tached to this electric current even now galvanic 
electricity as against frictional or static electricity. 
The series is therefore usually alluded to as the 
electro-chemical series of metals. 

Of the non-metals, oxygen occupies the extreme 
flank, with chlorine next, as sodium stands along- 
side of potassium : 0., Cl., Br., S., N., C. 

Valence. Glancing at the symbols H(C1), H 2 (S0 4 ) 
we cannot help but being struck by the fact that in 
one symbol there is but one hydrogen, whereas there 
are two of hydrogen in the other. We cannot 
remove one of these hydrogens without destroying 
the harmony, without breaking up the body com- 
pletely. To give expression to this fact we are led 
to the term valence, a slight difference of meaning 
from equivalence. We say the elementary group (Cl) 
is monovalent, because it finds its satisfaction with 
one volume-unit of hydrogen, monos = once ; the 
compound group (SO 4 ) is divalent, dis = twice, be- 
cause it must have two hydrogens to exist. We 



126 CHEMISTRY SIMPLIFIED. 

shall find later on elements as well as complex 
radicals whose valence are 3, 4, 5, 6 designated 
respectively as tri-, tetra-, penta-, hexavalent. I warn 
you not to be dazzled by these full, sonorous words ; 
they are but a short cut of speech. You can prove 
nothing by means of valence, because the expression 
valence only states a fact, yet is convenient as an 
expression. 

The atomic weights of elements, molecular weights of 
compounds, volume weights. We find that one vol- 
ume of chlorine unites with one volume of hydro- 
gen ; in symbols HC1. Chlorine gas is 35.5 times 
heavier than hydrogen gas hence the symbol stands 

HC1== 1 + 35.5 = 36.5 

Also we find that 35.5 grams of chlorine gas com- 
bine with 23 grams of sodium and thus produce 
35.5 + 23 = 58.5 grams of NaCl (common salt). 
Only one compound between Cl and Na has been 
observed with certainty and this is a very stable one. 
We assume that the vapor of sodium, if it could be 
produced and weighed, would be 23 times heavier 
than hydrogen, under the same conditions of tem- 
perature and pressure. Though the metal volati- 
lizes at red heat yet have all experimental attempts 
thus far failed, because the sodium vapor attacks all 
the vessels which are available : platinum, gold, 
silver, nickel, porcelain ; hence we do know only by 
inference that the volume of the mass unit weighs 23. 

Both by composition and decomposition (synthesis 
and analysis) we know that 35.5 grams of chlorine 
gas combine with 39 grams of potassium to form 



A CHAPTER OX THEORIES. 127 

35.5 + 39 grams of KC1. That 39 is the weight of 
one volume of potassium vapor we do not know any 
better than in the case of sodium, for the same diffi- 
culties. The symbol KC1 or XaCl is not a certainty 
in other words. Its strong probability follows from 
the following consideration. By acting upon sul- 
furic acid H 2 (S0 4 ) with either of the two metals we 
can produce well crystallized salts or vitriols to wit : 



either of which possesses strong acid reaction, and 



salts which are neutral towards litmus paper. The 
former salts convert into the latter thus : 

2XaH(SO) 4 + heat = XaNa(S0 4 ) + H 2 (S0 4 ) vola- 
tilized 

2KH(S0 4 ) + heat = KK(S0 4 ) + H 2 (S0 4 ) volatil- 

ized. 

Transposed into numbers this means that we can 
combine with one S (32 parts) either 23 or 46 of 
sodium, either 39 or 78 of potassium ; but with 23 
and 39 only when in each instance there is also one 
hydrogen present. Hence it follows that 23 of 
sodium, 39 of potassium, can take the place of are 
equivalent to one hydrogen in the two acids 

HC1, H 2 S0 4 . 
KC1, K 2 S0 4 . 
NaCl, Na 2 S0 4 . 



128 CHEMISTRY SIMPLIFIED. 

Potassium, sodium, hydrogen, on these given terms 
are monovalent metals, or monads (a still shorter 
expression), It is self-evident then that the oxyd 
of these metals must be Na 2 0, K 2 if the oxyd of 
hydrogen is H 2 0. The hydroxyds of the mefals 
sodium and potassium become Na 2 O.H 2 0; K 2 0.- 
H 2 0. But since we saw in the vitriols one hydro- 
gen being replaced by one Na, or one K, the same 
must be possible in water, to wit : 

H 2 + Na = NaHO + H (escapes). 

Hence it follows that the symbol Na 2 O.H 2 = 2 
(NaHO) expresses two units or molecules of sodium 
hydroxyd, that NaHO is the true representation of 
sodium hydroxyd. In the metallic hydroxyd we 
have, therefore, a combination in which the metal 
is united to the group (HO). A group which acts 
as a non-metallic radical of the value (valence) one. 
This group contains the metal H and the non-metal 
0, whilst the negative or non-metallic group (SO 4 ) 
contains the two non-metals. Perhaps in this 
hybrid nature of the group (HO) lies part of the 
reason for the action of the hydroxyd towards lit- 
mus and other actions totally opposed to the acids. 
The relative action, then, of the hydroxyds and 
acids is this : 

Na(HO) + H(C1) = NaCl + H 2 0, 
2Na(HO) + H 2 (S0 4 ) = Na 2 (S0 4 ) + 2H 2 O. 

Two attractions exist to account for the powerful 
action : First the greater attraction of the metal to 
the non-metallic radical and the tendency of (HO) 



A CHAPTER ON THEORIES. 129 

to become H 2 by taking another H. Owing to 
tbe important role of the group (HO) the name 
hydroxyl (ule = matter) is given to it. Hydrogen 
= the generator of water, hydroxyl = the matter 
from which water is made. * In the light of all these 
considerations and speculative deductions, the pre- 
vious definitions of base, acid, salt shall be changed 
to read as follows : 

Base = Combination of metal with one or more 
hydroxyl groups. 

Add = Combination of a non-metallic group or 
radical with one or more hydrogens. 

Salt = Combination of a metal with a non-metal- 
lic radical. 

The definitions of acid and salt are identical. 
The two things are of one kind. Sulfuric acid is 
hydrogen vitriol. 

The term vitriol has been abandoned for the sake 
of greater uniformity of chemical expressions. Its 
place is taken by the word sulfate, hence the fol- 
lowing : 

H 2 (S0 4 ) = Hydrogen sulfate = sulfuric acid. 
Na 2 (S0 4 ) = Sodium sulfate. 
NaH(S0 4 ) = Sodium, hydrogen sulfate. 
K 2 (S0 4 ) = Potassium sulfate. 
KH(S0 4 ) = Potassium, hydrogen sulfate. 
Ca(S0 4 ) = Calcium sulfate. 
Fe(S0 4 ) = Ferro sulfate (iron sulfate). 
Cu(S0 4 ) = Copper sulfate. 
Pb(S0 4 ) = Lead sulfate. 
Zn(S0 4 ) = Zinc sulfate. 
9 



130 CHEMISTRY SIMPLIFIED. 

You should accustom yourself to use the expression: 
hydrogen sulfate in place of sulfuric acid, though 
no harm is done by the latter. Logical consequen- 
tial speech leads to logical thought and work. 

Atomic weight of calcium, copper, lead, zinc. By 
analysis we find that 35.5 grams of chlorine unite 
with 20 grams of calcium to a stable chlorid. If 20 
were the representative of one volume of calcium 
vapor then the symbol of the chlorid would be CaCl, 
as NaCl. But we find that we can combine the cal- 
cium with the hydrogen sulfate, H 2 (S0 4 ), only in 
one way, not in two ways as with potassium and 
sodium, namely, so that 40 of calcium correspond 
to one (SO 4 ) or one S, that therefore the number 
40 must stand for the atomic weight of calcium, 
that one calcium is equivalent to two hydrogens and 
therefore the symbol of the chlorid must be written 
CaCl 2 . 

not -20Ca + 35.5C1 = CaCl, 
but 40Ca + 2 X 35.5 = CaCl 2 . 
Copper, zinc, lead, also form only one kind of sul- 
fate, Cu(S0 4 ), Zn(S0 4 ), Pb(S0 4 ), therefore, we say 
these metals are divalent like calcium, their unit 
weight stands for two hydrogens, and in each case 
35.5 chlorine combine exactly with one-half as much 
metal as 32 sulfur, hence their chlorids are CuCl 2 , 
ZnCl 2 , PbCl 2 . Copper makes an exception in so 
far as it can unite with chlorine in two ways, to wit : 
35.5C1 + 31.5Cu and 35.5C1 + 63Cu. The com- 
pound whose ratio of Cl : Cu is 35.5 : 31.5 is the stable 
compound, permanent at ordinary heat arid even 



A CHAPTER ON THEORIES. 131 

up to red heat. But since in the sulfate 32S cor- 
respond to 63Cu, therefore we take the number 63 
as the representation of one divalent volume of cop- 
per and write 

63Cu + 2 X 35.5C1 = CuCP, and 
2 X 63Cu + 2 X 35.5C1 = Cu 2 Cl 2 . 

In the first, the stable compound, cupric chlorid, 
CuOl 2 , the metal is normal, divalent. In the 
second, the unstable compound, cuprous chlorid, 
Cu 2 Cl 2 , the metal is abnormal, monovalent. Sil- 
ver acts like potassium. 107. 6Ag combine with 
one chlorine ; but 2 X 107.6 combine with one sulfur, 
32. Hence silver is monovalent, 107. 6 Ag = one H. 
The chlorid is AgCl, the sulfate is Ag 2 (S0 4 ). 

Gold unites with chlorine in two ways. In one 
compound, which is a white r powdery substance, we 
find 196Au with 35.5C1, in the other 65.33Au with 
35.5C1. The first compound is so unstable that it 
falls to pieces upon the addition of water. In the 
other compound the chlorine acts upon certain sub- 
stances as free chlorine. Besides, the specific weight 
of gold 19.5 is so high that necessarily the weight 
of its vapor must be very high (though we cannot 
make this vapor). We take, therefore, 196 to repre- 
sent the weight of one volume, and write the sym- 
bols of the two chlorids : 
196Au + 35.5C1 = AuCl = aurous chlorid, 
196Au + 3 X 35.5C1 = AuCl 3 = auric chlorid. 

Auric chlorid is a deep yellow substance, easily 
soluble in water, and fairly stable. In it gold = 



132 CHEMISTRY SIMPLIFIED. 

Au has the valence 3. In aurous chlorid Au has 
the valence 1. 

Molecular weight. Two or more simple bodies 
united into a chemical union form a molecule. By 
some it is contended that in the free state even the 
simplest bodies the elements form molecules, that 
in the free state hydrogen is (H.H) = 2, chlorine 
(C1.C1) = 71 ; oxygen (0.0) == 32, and H 2 (S0 4 ) - 
98 of course. When chlorine acts upon hydrogen 
the action must, according to this view, be repre- 
sented by : 



Nothing is changed, in reality, by adopting this 
view, or by rejecting it. If we speak of molecular 
weight we shall invariably mean that the molecule 
is composed of several elements. 

Relation between atomic weights and specific heat of 
the elements. By heat capacity the physicists under- 
stand the quantity of heat energy expressed in 
calories (heat units), which is necessary to raise the 
temperature of a mass equal to one gram of a sub- 
stance by one degree of the centigrade thermometer. 
The specific heat of a body (solid or liquid) means its 
heat capacity referred to that of water as the unit. 
The specific heat of gases is referred to that of air or 
also to that of water as units. The variation of 
values thus obtained is highly astonishing. In gen- 
eral, the heat capacity of metals is very low, that 
is, a metal shows the heat very quickly, water very 
slowly. The numbers representing the specific 



A CHAPTER ON THEORIES. 133 

heats are therefore always true decimal fractions. 
When the atomic weights of the metals are multiplied 
by their specific heats the product is a constant. Reason 
therefore demands that whenever the product is not 
equal to the constant, there must be something 
wrong, that we stand before a riddle. The follow- 
ing numbers show this relation, which is also 
known as the " Law of Dulong and Petit : " 

A. W. Spec. Heat. Product. 
Silver Ag 108 X 0.0570 = 6.156 

Iron Fe 56 X 0.1138 = 6.375 

Copper Cu 63 X 0.0952 5.99 
Zinc Zn 65 X 0.0955 = 6.207 

Calcium Ca 40 X 0.167 - 6.68 
Sodium Xa 23 X 0.2930 = 6.73 
Potassium K 39 X 0.1655 = 6.45 

Lead Pb 207 X 0.0314 == 6.499 

Tin Sn 118 X 0.0562 = 6.631 

These numbers do not show exactly the same pro- 
duct for all the metals, but the constant appears to 
be about 6.5. 

Inversely it would follow that the specific heat of 
the atomic volume is the same for all the metals ; the 
specific heat is an inverse function of the mass; the 
greater the specific gravity, the smaller the specific 
heat. 

REVIEW OF THE ACTION OF CHLORINE ON THE ALKA- 
LINE HYDROXYDS. 

The action of chlorine upon the alkaline hy- 
droxyds is so important, theoretically and practi- 



134 CHEMISTRY SIMPLIFIED. 

cally, that we must now transcribe the symbols for 
those reactions according to the notion of valence : 

1. 2K(HO) + 2C1 = K(C10) + H 2 0. The radical 
(CIO) should be called chloryl like hydroxyl, but 
this name is rarely met with. It cannot be iso- 
lated, it has no real existence, it is unbalanced ; 
C1 2 is the balanced or saturated molecule. 

Cl 2 Dichloroxyd is at ordinary temperature a 
reddish-yellow gas of penetrating odor. Specific 
gravity = 2.977. 1 cubic centimeter weighs 0.0039 
grams, nearly 4 mgs.; 1 c.c. of chlorine weighs 
0.00317; 1 c.c. of oxygen weighs 0.00143. 2 
volumes 01 + 1 vol. = 2 X 0.00317 + 0.00143 - 
0.00777. If the latter sum be divided by two we 
get 0.00388 which is equivalent to the experi- 
mental weight 0.0039. Hence it follows that 2C1 + 
10 = 3 vols., in combining to Cl 2 contract one- 
third. We found this to be so for SO 2 and for H 2 0. 
We may deduce the general law that two volumes of 
one element combining with one volume of another ele- 
ment always produce two volumes of the combination. 
Thus is explained why the unit weight of a com- 
pound can be greater than the sum of the unit 
weight of its composing elements. 

C1 2 becomes a blood-red liquid, when the gas 
is conducted into a tube which stands in a freezing 
mixture. The liquid is terribly explosive. A 
scratch with the file on the glass tube may cause an 
explosion; the C1 2 just breaking up into Cl 2 + 0. 
This is an interesting fact. For in spite of C1 2 
being a compound like water IPO, yet whilst the 



A CHAPTER ON THEORIES. 135 

latter is strongly cohering, the former has little 
coherence, because in C1 2 we have two non-metals, 
whilst in H 2 we have metal and non-metal. The 
compound C1 2 is made by acting with chlorine 
upon the oxyd of mercury, thus : HgO + 4C1 = 
HgCl 2 + C1 2 (reddish-yellow gas). In its actions 
upon metals this body is more energetic even than 
chlorine itself. 

When chlorine acts upon K(HO) or Na(HO) or 
Ca(HO) 2 at boiling heat the following actions occur : 

6K(OH) + 6C1 + boiling heat = K(C10 3 ) + 5KC1 + 

3H 2 
6Na(OH) + 6C1 + boiling heat = Na(C10 3 ) + 

5NaCl + 3H 2 O 

6Ca(OH) 2 + 12C1 + boiling heat = Ca(C10 3 ) 2 + 
5CaCl 2 + 6H 2 

The important products are K(C10 3 ), Na(C10 3 ), 
Ca(C10 3 ) 2 . These bodies we will designate chlo- 
rates. The group (CIO 3 ) is a monovalent radical 
but has no real existence ; neither do we know the 
corresponding chloroxyd C1 2 5 . But we can pre- 
pare the hydrogen chlorate, H(C10 3 ). It forms a 
thick, syrupy liquid at ordinary temperature, has 
strong acid taste, no odor. Above 40 C. it begins 
to give out chlorine and oxygen. 

Potassium chlorate, is as above stated, the most 
important of the chlorates, because with it we can 
generate chlorine gas easily in immediate contact 
with the bodies to be acted upon : 

KC10 3 + water + 6HC1 =; KC1 + 6CI + 3H 2 0, 



136 CHEMISTRY SIMPLIFIED. 

Generation of pure oxygen gas by means of potassium 
chlorate. 

Equation KC10 3 + heat = KC1 + 30 
Converted into figures this means : Molecular weight 
of KC10 3 = 39 + 35.5 + 3 X 16 = 122.5 grams, 
give 48 grams oxygen gas. One cubic centimeter 
of oxygen weighs 0.00143 grams, hence 48 grams = 
o. 4 o s i43 c.c. = 33636 c.c. = 33.636 litres = 0.033636 
cubic meter. 

Problem. Let a gas holder be a sheet-iron cylin- 
der with the dimensions : Diameter = 13.5 inches, 
height = 27 inches. How many grams of potas- 
sium chlorate will be required to fill this holder 
with oxygen? 1 inch equals 2.5 centimeters = 
0.025 m. 



CHAPTER IX. 

BROMINE, IODINE, FLUORINE. 
BROMINE. 

IN the process of salt-making from natural and 
artificial salt wells, the brine (salt solution) is evap- 
orated. At a certain concentration of the boiling 
liquid, salt crystals fall out and keep on precipitat- 
ing up to a given point. The crystals are steadily 
removed by means of a sieve-ladle. Finally a 
heavy solution remains from which no crystals of 
salt fall. This solution is the mother liquor. It 
contains the chlorids of calcium and magnesium, 
CaCl 2 + MgCl 2 + x, x being the combination of the 
new element bromine, from Greek bromos = stench, 
with magnesium. If the mother liquor be heated 
with H 2 S0 4 and MnO 2 the liquid becomes dark 
red-brown and heavy red-brown vapors appear 
above it. The vapors condense in a water-cooled 
receiver to a deep red-brown liquid, almost black, 
and emit a strong, irritating, suffocating odor 
(indicated in name). Specific gravity = 3.187 at 
C., 2.97 at 15 C. It boils at 63 C. and 
760 mm. It becomes a brown-red, crystalline solid 
at 24 C. The symbol for bromine is Br. Bromine 
gas is 80 times heavier than hydrogen. In most of 
(137) " 



138 CHEMISTRY SIMPLIFIED. 

its chemical actions it is similar to chlorine. It is 
soluble in water ; 1 part of bromine dissolves in 33.3 
parts of water at 15 C. The solution is blood-red in 
color, and gives off bromine vapors. It is soluble in 
ether, alcohol, chloroform and carbon disulfid. If a 
water solution, containing little bromine, be shaken 
with carbon disulfid, the bromine will leave the 
water and pass into the carbon disulfid. 

1 vol. Br. + 1 vol. H + heat = 2 vols. HBr. 
Hence Br is monovalent like chlorine. The result- 
ing HBr, hydrogen bromid is a colorless pungent gas 
like HC1. Liquefies at 73 C. into a colorless liquid, 
which becomes solid when the liquid HBr is al- 
lowed to evaporate in the air. One c.c. weighs 
0.003616 gr. HBr is eagerly absorbed by water, 
and is then named hydrobromic acid. The highest 
concentration is 82 per cent. HBr, corresponding to 
HBr -f- H 2 0. HBr dissolves metals except Ag, Cu, 
Hg, Pb, because the resulting bromids AgBr, 
Cu 2 Br 2 , Hg 2 Br 2 , PbBr 2 , are not soluble. HBr 
combines with the hydroxyds, as HC1 does thus 
Na(HO) + HBr = NaBr -f H 2 0, 
Ca(HO) 2 -f 2HBr - CaBr 2 + 2H 2 0. 
Bromids and oxybromids form when bromine acts 
upon the alkaline hydroxyds, thus : 

2Na(HO)+water+2Br = NaBr+Na(BrO)+H 2 0, 
6Na(HO) (concentrated) +6Br=5NaBr+NaBr0 3 
+ 3H 2 0, 

6K(HO) (concentrated)+6Br = 
3H 2 0, 



BROMINE, IODINE, FLUORINE. 139 

Potassium br ornate, KBrO*, is even more insoluble 
than KC10 3 . If therefore bromine be added to con- 
centrated solution KOH (1:3) until the liquid re- 
tains a permanent j-ellow color, KBrO 4 will fall out 
as a crystalline, colorless powder; KBr remains in 
solution. KBrO 3 can be made pure by dissolving 
the powder in boiling water, when the salt will 
crystallize on cooling. 

The most important salt is sodium bromid, NaBr. 
It forms a part of bromo seltzer ; is much prescribed 
by physicians against headache. Tons of it are 
consumed annually. 

Bromine itself and bromine water are valuable 
oxidizing agents in the hands of the chemist. Thus, 

SO 2 + 2H 2 + 2Br = H 2 (S0 4 ) + 2HBr. 
Upon heating the solution, HBr escapes with aque- 
ous vapor and leaves hydrogen sulphate. There 
are many similar actions, with which we shall meet 
hereafter. 

IODINE. 

Before the discovery of bromine a French chem- 
ist, Courtois, had found a strange action in the 
mother liquor of the varec. By this name the 
peasants of the Channel Coast in northern France 
designate the extract from the ashes of the sea 
weeds which are thrown ashore by the storm. These 
ashes show alkaline reaction like the ashes of land 
plants, but it was recognized that the sodium carbon- 
ate is the principal component, not potassium car- 
bonate, as in wood ashes. When the strained lye 



140 CHEMISTRY SIMPLIFIED. 

from the water extraction is boiled down, potassium 
sulfate falls out first (being least soluble), then falls 
Na 2 S0 4 + 2H 2 0, then NaCl, then Na 2 C0 3 -f 
3H 2 0, finally leaving a mother liquor quite strongly 
alkaline, but containing still NaCl, together with 
Na 2 C0 3 and small quantities of sulfur-compounds 
of sodium. To this mother liquor H 2 S0 4 + water 
(1.7 sp. g.), pan acid, is gradually added until the 
solution is decidedly acid. CO 2 escapes and hydro- 
gen sulfid, while a scum forms, chiefly consisting of 
sulfur. After this scurn has been dipped out and 
the solution has become quite clear, it is transferred 
into a retort (cast iron with a leaden alembic or 
cap), manganese dioxyd is added and heat applied. 
Iodine vapors are given off which become a black 
crystallized sublimate in the receiver, made of earth- 
enware. It is, however, impure with salts and 
water. The water is allowed to drain off, the re- 
sidue redistilled with quicklime, which absorbs the 
remaining moisture. The nitre works of Chili fur- 
nish a mother liquor from which large quantities of 
iodine are manufactured. So also from the mother 
liquor of the chemical works at Stassfurt, Germany. 
In fact iodine or rather an iodid (either Nal or 
Mgl 2 ) is contained in the sea water, thence it gets 
into the algae (sea weed); also into the salt beds of 
the earth ; thence into all salt springs and wells. 
More in some places than in others. The sea weed 
contains up to 0.6 p. c. of iodine, but most of it gets 
lost in the drying and the burning. All iodine pro- 
ducers are in a big trust, maintaining high prices. 
Probably a million pounds are consumed annually. 



BROMINE, IODINE, FLUORINE. 141 

Properties. At ordinary temperature a grey-black 
solid, always crystals or crystal fragments ; metallic 
lustre; emits a strong, unpleasant odor. It is very 
soft. Sp. G. 4.958. Melts at 107 0.; boils at 
180 C. The vapor of iodine is of a beautiful violet 
color. The name iodine from iodos similar to 
violets, was given for this color, which is so very 
characteristic and even unique. Water does not 
dissolve iodine freely. One gram I dissolves at 
10-12 C. in 5524 grams of water. This solution 
is known as iodine water. It bleaches the same as 
chlorine water. Much more soluble in alcohol. 
This solution is known as tincture of iodine, much 
used by physicians, to relieve swellings of the skin. 
Makes a dark -brown stain on the skin, on wool or 
silk. Iodine dissolves readily in a water solution 
of potassium iodid, KI, giving a yellow, brown or 
blood-red liquid. Soluble in ether, in carbon di- 
sulfid. If a trace of iodine be contained in much 
water, or salt solutions, a few drops of carbon di- 
sulfid, shaken with the water, will absorb all the 
iodine and assume a rose color or purple color. The 
vapor of iodine is 127 times as heavy as an equal 
volume of hydrogen at the same temperature. 
Hence 127 is the atomic weight ; the symbol is I. 

Starch and iodine. If starch be boiled to thin 
paste, and the paste filtered, making a clear solu- 
tion, then this colorless solution will become in- 
tensely blue if a small quantity of iodine solution be 
added. Starch -f iodine equals blue body. Thus 
we can recognize starch from other parts of a plant 



J42 CHEMISTRY SIMPLIFIED. 

or seed by means of iodine, and detect iodine in 
solution with other bodies. 

Chemical properties. Iodine combines with the 
metals directly forming iodids. K -f I KI (with 
explosive energy), Na + I = Nal, the two elements 
melt together without explosive display. Hg -f 21 -f 
heat = HgP (producing light) a scarlet-red body. 
Hg -f I == Hgl, a green-yellow body. These iodids 
are decomposed by bromine ; 

KI + Br == KBr -f I. 
Then in its turn KBr + Cl give KC1 + Br. 
Chlorine, bromine, iodine form a series whose chem- 
ical affinity is inversely as their atomic weights 
which are 35.5, 80, 127. The greater the mass, the 
more sluggish the activity. 

Iodine does not readily combine with hydrogen, 
as chlorine does. It requires a high temperature. 
(6030 calories.) 

Hydroiodic acid, HI -f- water is best prepared by 
working along the equation 

21 + IPS + water = 2HI + water + S. 
We keep the finely powdered iodine stirred up in 
water whilst the gas EPS is passed into the water; 
the color of the solution disappears. HI is then 
dissolved in the water, the sulfur is to be removed 
by filtration. The liquid is strongly acid, smells 
pungent like HC1 and acts upon metals and 
hydroxyds in a general way the same as HC1. A 
solution of Ag 2 S0 4 -f HI -f- water gives a yellow 
precipitate of Agl, while HC1 produces a white pre- 
cipitate of AgCL 



BROMINE, IODINE, FLUORINE. 143 

One does not often have occasion to prepare and 
use HI. 

Oxyiodids, iodates, hydrogen iodate, HIO*. By the 
action of iodine upon KHO we obtain KI and 
K(I0 3 ). 6KHO + 61 == 5KI + K(IO*) + 3H 2 0. 
Potassium iodate is slightly soluble in water. If 
K(C10 3 ) be dissolved in water, to the liquid finely 
powdered iodine added and the solution boiled, 
then the iodine will displace the chlorine. 
5K(C10 3 ) + 61 + 3H 2 + heat = 5K(I0 3 ) + 

5HC1 + HIO 3 . 

From an iodid as KI chlorine displaces iodine ; 
but from a chlorate iodine displaces chlorine, we 
say : Iodine has a stronger affinity for oxygen than 
chlorine. We make use of this property in quanti- 
tative analysis. 

H(10*), Hydrogen iodate, iodic acid is formed by 
acting with chlorine gas upon water in which finely 
ground iodine is suspended 

3H 2 + I + 5C1 = H(I0 3 ) + 5HC1. 

If a dilute solution of NalO 3 be heated and chlorine 
be passed through until no further precipitation of 
salt be noticed, then the precipitate is Na' 2 (I0 6 )H 2 or 
Na 2 O.H 2 0(I0 4 ) sodium hydrogen periodate, and 
from this can be made the silver salt Ag(I0 4 ), silver 
periodate. 

General remarks. The most important compound 
of iodine is KI, potassium iodid, which forms white 
or colorless cubic crystals, like KBr, KC1; the three 
salts are isomorphous, have equal form and can re- 



144 CHEMISTRY SIMPLIFIED. 

place each other in any crystal. We can have a 
crystal, any particle of which contains K, Cl, Br, I, 
even the very smallest. This leads us to the con- 
clusion that Cl or Br do not in reality stand for one 
smallest unit, but that they represent a vast number 
each of smallest units; roughly, the circle represents 
the active unit, but the dots mean smallest particles 
so that one active unit may contain any number of 
isomorphous particles as Cl, Br, I. The two 
spheres, Fig. 42, mean the molecule K(C1, Br, I). 

FIG. 42. 




The sphere representing potassium contains also a 
multitude of smallest particles, which in their turn 
may be a mixture of any number of isomorphous 
metals, such as Na, Ag. That is, the smallest frag- 
ment of a microscopic cube might contain (K, Na, 
Co, Rb, Tl), (Cl, Br, I). Minute quantities of iodine 
are found in the blood of man and animals as well 
as in plants, more particularly in the bones of the 
animal. We find iodine in the mineral iodyrite, 
y among silver ores in yellow hexagonal crystals. 



FLUORINE. 

The mineral fluorite, fluorspar from German fluss- 
spath, occurs widely as gangue (German gang = vein) 



BROMINE, IODINE, FLUORINE. 145 

or vein-matter with silver-le'ad ores, sometimes fill- 
ing considerable fissure veins all by itself. The 
German miners call all minerals which are trans- 
parent or translucent and possess strong cleavage, 
spath, thus calcite is kalkspath, iron carbonate is 
eisenspath, orthoclase is feldspath, and our present 
mineral was named flussspath because the smelters 
noticed that it melts not only by itself, but causes 
other gangue minerals to become fluid, in other 
words, to act as a flux in smelting. Fluss = flux, 
whilst fluere is Latin for to flow. 

Fluorite is characterized by its isometric crystals, 
cubes, octahedrons, tetrahexahedrons, hexoctahe- 
drons, and its strong cleavage parallel to the faces 
of the octohedron. It scratches calcite, is therefore 
harder. Mostly colored green, purple, pink, blue, 
black, yellow, yet these colors are accidental, do not 
belong to the substance of the mineral itself, which 
is colorless or white. Shows no taste, therefore in- 
soluble in water. 

Fluorite melts just at the temperature glass melts ; 
experiment to be made in a small platinum spoon 
or crucible ; no gas will be given out. If, however, 
we put a piece of the spar upon charcoal and direct 
a strong oxydyzing flame upon it, the spar will melt 
at first, but after some time will solidify. Why? 
Because the conditions are different from those in 
the crucible. The flame itself is not a mere source 
of heat, but a mixture of gases at high temperature. 
Among the gases 'are aqueous vapor and oxygen 
(from the air). We know both to be powerful 
10 



146 CHEMISTRY SIMPLIFIED. 

agents when assisted by heat. Indeed, by bringing 
the nose near the charcoal, a pungent odor becomes 
noticeable ; the spar decomposes under the influence 
of aqueous vapor and heat and oxygen. The residue 
assumes more and more the appearance of lime, 
glowing incandescence. By acting upon the finely - 
powdered spar with H 2 S0 4 , in a test-tube, there 
appears no action at ordinary temperature. Upon 
applying heat, gas bubbles arise, slowly at first, 
finally in large number, so that the liquid froths. 
A gas evidently escapes. To the nose the gas is 
pungent, acrid, recalling HC1, but more repelling. 
Litmus turns red at once in the gas. 

Investigation of the gas. Hypothesis : Having an 
odor like HOI, we may infer that the gas is a com- 
pound H n X m or perhaps simply HX ; and proceed- 
ing a little further with the assumption that X is a 
new element, let X at once be represented by the 
letter F (first of fluor spar) ; hence the gas may be 
H n F m or perhaps HF. At the outset in the in- 
vestigation, we find ourselves confronted with a 
serious difficulty. Namely we find the test-tube, 
which was used in the first experiment, strongly cor- 
roded, after it is washed out with water : The gas 
evidently decomposes glass. This unwelcome fact 
it is true puts a sure stamp of originality upon the 
new element, quite unlike any other thus far met 
with, but at the same time excludes the use of glass 
tubing and all other glassware. On porcelain it 
acts as on glass ; on iron and zinc it acts strongly, 
also on copper and silver. Not so on lead, gold and 



BROMINE, IODINE, FLUORINE. 



147 



platinum, nor on wax, paraffine or rubber. The 
latter materials do not stand heat. We are thrown 
then upon the three metals, of which lead is the 
cheapest. The gas acts somewhat upon the lead 
surface, but the product of the action being nearly 
insoluble, the metal answers well enough for all 
ordinary purposes. We construct a distilling ap- 
paratus of which Fig. 43 gives a sectional represen- 

Fio. 43 




tation. C is a cup of sheet lead with a ring-shaped 
groove G at the rim. The cup sits in an iron cup 
forming a sand bath, this resting on the tripod T. 
Into the groove G fits the alembic or helmet A, 
with the tube neck N. After filling the mixture of 
fluorite powder and H 2 S0 4 (so much acid that a 
thin mush forms) at M into the cup C', the alembic 
A is set into the groove G, and the latter filled with 
plaster of paris and water. The plaster sets and 
forms a gas-tight joint. The platinum dish D is 
partly filled with pure water and so placed under 
JV that the water level L just covers the mouth of 



148 CHEMISTRY SIMPLIFIED. 

N. D may be set into another dish and surrounded 
with snow and ice or salt. When the lamp is put 
under the sand bath, the air is first driven out, then 
the gas appears and dissolves in the cold water. If 
we substitute a cylindrical bottle of lead or platinum 
for the dish, the gas itself will condense into a liquid; 
specific gravity at 12 C. 0.988, nearly equal to 
water. This liquid boils at 19.5 C. It fumes in 
the air ; the gas combining with the moisture of the 
air gives the visible fume. Fumes cause violent 
coughing, and may produce death if taken into the 
lungs. A drop of the liquid will produce on the 
skin a white spot, a blister forms, bursts and a pain- 
ful, slowly healing ulcer forms. Be very careful 
with this concentrated liquid ; but even the dilute 
water solution has given one much discomfort, 
when some of it got under the finger nails. The 
perfectly dry gas does not attack glass ; the least 
moisture causes an immediate attack ; the glass be- 
comes opaque, we say the fluorspar gas, or liquid, 
etches glass; German aetzen, French mordre^ to bite. 
To etch means to bite out something. 

Composition of the gas. When the gas acts upon 
Na, K, Zn, Fe, two products arise : Hydrogen -f- 
Me n F m (metallic fluorid). When it acts upon hy- 
droxyd : H 2 + Me n F m result. 

KHO + HF m = K n F m + H 2 0. 

That the gas is a hydrogen compound of the radical 
F there can be no doubt. But there is a difference 
about the valence of F. Because there is, as with 




BROMINE, IODINE, FLUORINE. 149 



the molecule H 2 S0 4 (see above) the existence of 
two salts to wit NaHF* and NaF x , In the latter 
23 Na (sodium) are combined with 19 fluorine (F), 
but in the former 23 Na are combined with one H 
and 38 F. If we admit the proof power of this acid 
salt (as with the sulfate) then fluorine (F) is divalent, 
the sodium fluorid is Xa 2 F, the atomic weight of 
F = 38. There are, on the other hand, quite 
weighty reasons why we should assume F to be 
monovalent. Chiefly the closeness between its ac- 
tion and that of chlorine is convincing to the large 
majority of chemists to declare fluorine a monad 
and its atomic weight = 19. 

Sodium fluorid is thus made NaF. The acid salt 
is XaH(F 2 ). The solution of HF in water is hydro- 
fluoric acid. The acid is in all actions closely like 
HC1, in some instances however fluorids are unlike 
chlorids. When a water solution of silver sulfate 
is added to HF + water, no precipitate falls, the 
AgF being easily soluble in water, whilst AgCl is 
insoluble in water. On the other hand, calcium 
chlorid CaCl 2 is very soluble in water, calcium 
fluorid CaF 2 is insoluble in water. 

The etching process. We need in the laboratory 
graduated glass vessels, tubes and flasks ; or we want 
to mark and number the vessels. Hydrogen fluorid, 
or the acid salt XaHF 2 is invaluable for this pur- 
pose ; they can be bought ready for use, being sold 
either in caoutchouc or ceresine bottles (ceresine is 
mineral wax). First cover the glass with a thin 
film of paraffine or of wax. Melt these materials, 



150 CHEMISTRY SIMPLIFIED. 

warm the glass and apply the liquid material with a 
brush. After cooling draw the mark or number upon 
the wax or paraffine film ; then scratch away the film 
(with a steel point) all the lines or dots which are to 
appear in the etching. After this two ways are 
open : (1) to expose the engraved spot to the slow 
vapors of HF (this gives the best result); or, (2) to 
apply the liquid HF by means of a camel's hair 
brush repeatedly, according to the desired depth of 
the etching. There is a so-called glass ink on the 
market which appears as a milky white liquid. It 
is a solution of the acid salt NaHF 2 mixed with 
plaster of paris. 

The nature of fluorine. When HF is made to act 
upon metallic peroxyds as MnO 2 , water is produced, 
MnF 2 and a mixture of oxygen with fluorine. 
Many statements by experimenters are on record 
contradicting each other. The work is exceedingly 
difficult arid expensive. No pure fluorine has as 
yet been obtained by the above method. This 
much seems certain, that fluorine possesses a color 
similar to that of chlorine, i. e. yellowish-green, that 
its odor is similar to that of chlorine, that it attacks 
all substances except fluorspar, especially platinum 
and glass, and bleaches indigo. This state of affairs 
explains why we are uncertain about the valence 
and the atomic weight. 

The metal contained in fluorspar. After the mix- 
ture of spar powder with H 2 S0 4 has been heated 
until HF no longer escapes, but the thick white 
fumes of H 2 S0 4 , that means when complete decom- 



BROMINE, IODINE, FLUORINE. 151 

position has taken place, we find the residue to be a 
semi-solid which is soluble in a large quantity of 
water. From the solution precipitate characteristic 
monoclinic crystals of calcium vitriol = calcium 
sulfate or gypsum. There may be minute quantities 
of other metals, which do not now concern us. 
Calcium is therefore the metal of fluorite, it is cal- 
cium fluorid, CaF 2 . 



CHAPTER X. 

LECTUEE ON NITER OR SALTPETER. 

SALTPETER or niter is the name at present given 
to a peculiar salt of immense technical or industrial 
importance. The word saltpeter is the corruption 
of Latin = sal petrae = salt of the rock ; niter is de- 
rived from Hebrew-Egyptian = neter thence Greek 
= natron-nitron, thence Latin nitrum, the meaning 
of which has been explained above as original for 
natrium = sodium. At the present time the name 
applies to something very different from either rock 
salt or soda. It applies to two salts, one forming 
always prismatic crystals of the orthorhombic sys- 
tem, and the other appearing in grains, roughly re- 
sembling common salt. On closer examination the 
granular crystals are seen to possess rhomboid faces 
not rectangular as in the cube. Geometrically a 
cube and a rhombohedron are riot different except 
as to the position of the faces in regard to a system of 
arbitrary axes. It is quite possible that a crystal- 
lographic rhombohedron has rectangular faces, and 
a crystallographic cube has facial angles slightly 
deviating from 90. The action of a crystal towards 
the polarized light alone determines the system of 
crystallization. The angle of the pole edges is 
106 30' very near the angle of the cleavage rhom- 
(152) 



LECTURE ON NITER OR SALTPETER. 153 

bohedron of calcite, which is 105 30'. At all 
events the obliquity of the angle is large enough to 
exclude the idea of the cube. 

The prismatic niter is known as potash niter, the 
granular rhombohedral variety is known as Chili 
niter or soda niter. Both varieties are easily soluble 
in water, show a cooling taste ; nevertheless, there 
is a marked difference in the solubility of the two 
forms of niter. 100 grams of water dissolve 

Soda Niter. Potash Niter. 

at 6C. 68.8 at C. 13.3 

+ 10 C. 84.3 +18 C. 29.0 

+ 20 C. 89.5 +45 C. 74.6 

-1-100 C. 168.2 +97 C. 236.0 

Between and 100 C. the ratio of solubility is 
for soda niter f- = f ; for potash niter - 2 r 3 / = \ 8 -. 
Both niters melt easily. Potash niter, when held 
in the flame, gives a purple color, soda niter a 
yellow color to it. About the localities and condi- 
tions where and under which the niters are found, 
we will speak at the end of this investigation, as you 
will be better able to understand several of the 
intricate questions which arise in connection with 
these bodies. 

Investigation of the soda' niter. Let first a crystal 
fragment be heated in a closed tube. When the 
heat rises to redness, we notice gas bubbles. On 
trying the gas we find it to act like oxygen, being 
without odor, and being able to fan a dark red 
glowing taper into bright incandescence. Now let 



154 CHEMISTRY SIMPLIFIED. 

us drop a small piece of feathered tin into the molten 
niter. Notice the intense action, emission of light 
and conversion of the tin into white oxyd. Repeat 
these actions with sulfur, with antimony, with char- 
coal ; in all these cases there is displayed the phe- 
nomenon of burning, of combustion. Similar action 
is displayed by melting potassium chlorate. We 
may then rightly infer that niter is a salt similar to 
K(C10 3 ), or Na(C10 3 ), but that the salts are not 
identical follows from several reasons : (1) unlike 
form of crystals, (2) great difference in solubility, 
(3) that the chlorates part with their oxygen easily 
at low temperature, whilst niter only parts with it 
at red heat, (4) that a brown gas arises from the 
niter when it burns up a piece of metal, of sulfur or 
wood, (5) that this brown gas is suffocating. The 
unavoidable conclusion points to the existence in 
niter besides sodium and oxygen, of another un- 
known element. Let this element be designated by 
N the first letter of niter, and let it be pronounced 
nitrogen = generator of niter ; then soda niter will 
most probably be Na n N m O p , and of potash niter, 
K n N m O. What is the nature of N ? What is the 
ratio of its combination, what are the numerical 
values of n, m, p? 

(1) What is the nature of N of nitrogen? Let us 
return first to that experiment in which the niter 
was heated by itself, yielding oxygen. On acting 
upon it with water we will get a solution which 
shows strong alkaline reaction ; the niter itself has 
a neutral reaction neither acid nor alkaline. This 



LECTURE ON NITER OR SALTPETER. 155 

may mean that Xa*0 has formed, and likewise that 
a compound has formed with less oxygen than the 
original niter, i. e., Na n N m O p ^. Incidentally we 
noticed a strong corrosion of the glass tube at the 
places where the niter had been longest exposed to 
the flame, which suggests Na 2 O, because we know 
from handling NaOH and Xa*C0 3 in the glass 
tubes that these bodies attack the glass at high heat. 
In the water solution would either be Na(HO) -+- 
Xa u X m O p " q or only one of the two. Addition of 
dilute H 2 (S0 4 ) will neutralize Xa(HO). 

2XaHO + H 2 (S0 4 )= Na 2 (S0 4 ) + H 2 0=neutral ; 
a further addition of H 2 (S0 4 ) will cause the evolu- 
tion of a gas of peculiar odor, rather aromatic. The 
gas may be H 2 N m O p " q or not ; at any rate it is a 
peculiar body. Now let us act with concentrated 
H 2 (S0 4 ) upon the original niter. At ordinary tem- 
perature there is but little if any action, except that 
the niter seems to dissolve, at least partly, and but 
a faint odor is noticed. As heat is applied, efferves- 
cence ensues. A sour, pungent gas appears, which 
condenses in a sufficiently cold receiver into a liquid, 
or else is energetically absorbed in water. In the 
residue we have sodium hydrogen sulfate + hydro- 
gen sulfate. We pour it into a porcelain dish, and 
may convert it into salt cake by means of heat ; 
prove it to be Xa 2 S0 4 by means of its easy solu- 
bility in water and its resistance to crystallization. 
Only low temperature will induce crystals. The 
liquid distillate we will name spirits of niter. We 
study its action upon the metals, upon paper, wood, 



156 CHEMISTRY SIMPLIFIED. 

the skin, wool, in fact upon all bodies known to us 
and handy to procure. For remember always that 
chemistry means try anything upon everthing else. 
All the actions will be remarkable. 

Lead (Pb) + sp. niter -f heat=white salt + brown 
fumes. 

Copper (Cu) + sp. niter=blue salt -f- brown fumes. 

Silver (Ag)+sp. niter=white salt-f brown fumes. 

Filter paper -h sp. niter -j- heat=solution+brown 
fumes. 

Gold (Au) -f- sp. niter -f heat = no action. 

Platinum (Pt) -f sp. niter 4- heat = no action. 

Tin (Sn) + sp. niter=white oxyd + brown fumes. 

Hydrochloric acid (HC1) -j- sp. niter + heat = 
brown liquid -f- brown fumes. 

HC1 + sp. niter-j-gold -j- warm = yellow solution, 
AuCl 3 -f brown fumes. 

HC1 -f sp. niter -f platinum = yellow-brown solu- 
tion -|- brown fumes. 

The spirits of niter proves itself thus one of the 
most powerful agents. The Arab chemist Geber 
was the first to mention this body. The Latin 
translation of his works speaks of it as aqua fortis 
(the strong water) or aqua dissolutiva (the dissolving 
water) because it dissolved both silver and lead. 
But the combination of the spirits of salt (HC1) with 
the spirits of niter went, and still goes, by the name 
aqua regia (the kingly water), because it dissolves 
gold, the very king of the metals. 



LECTURE ON NITER OR SALTPETER. 



157 



On the other hand, if we dilute first the spirits of 
niter with water, very considerably, then we get 
hydrogen when acting upon either iron or zinc, but 
not with lead, copper or any other metal ; with all 
of these it is either brown fumes or nothing. Re- 
member the similarity with the actions of oil of 
vitriol or of the concentrated sulfuric acid. Con- 
centrated acid on the metals gave vitriols and SO 2 ; 
diluted acid on iron or zinc gave vitriols and H. 
Just as SO 2 was demonstrated as an oxyd with less 
oxygen than the sulfur oxyd which constitutes the 
sulfuric acid, so it follows logically that in the action 
of the strong spirits of niter, the brown fumes must 

FIG. 44. 




constitute a lower oxyd of the nitrogen, the element 
whose properties we are after. But if thus the 
metals can take away oxygen from the nitrogen, we 
argue, at a temperature below even the boiling-point 
of water, will it not seem probable that at a still 
higher heat more will be taken, or perhaps even 
all? 

We set up an apparatus as shown in Fig. 44. F 
is a small flask with twice perforated stopper. 



158 CHEMISTRY SIMPLIFIED. 

Through the latter pass the stem of a funnel 2 and 
the delivery tube 3. In F we place finely divided 
copper, K (gauze, granules, chips). The funnels hold 
the diluted spirits of niter. 3 connects with U-tube 
4-. The latter is partly filled with concentrated 
H 2 S0 4 forming a trap to dry and control the escap- 
ing gas. 5 is a tube filled with quick -lime (CaO) 
between two cotton plugs. In the charcoal furnaces 
F', F', lie the hard glass tubes T, T', each charged 
with rolls of copper wire-gauze. By means of rub- 
ber tube 6j T' connects with the bell jar B, which is 
filled with boiled water (in order to expel any ab- 
sorbed air). Before connecting F with tube 7 we 
heat up the furnaces and pass hydrogen through 
T, T', in order to have perfect metallic surface on 
the copper. The tube 5 will act as dryer and will 
also retain any gas of an acid nature. While the 
action of hydrogen was going on in T, T', we have 
utilized time by starting the action in F so that all 
the air is driven out by the gas. We regulate the 
flow of liquid from the funnel, so that, if possible, 
the sulfuric acid trap in 4- will indicate the passing 
of a slow current of gas. The slower and steadier 
(not in gulps) the current, the better will be the 
chances of a perfect deoxydizing action. Before 
connecting T with tube 5 by a rubber tube 7 we re- 
move most of the charcoal from F, I ', let the tubes 
T, T' come down below red heat, for the unknown 
niter gas, being an oxyd might produce with the 
hydrogen an explosive mixture. When we connect 
7 with T' we wait a sufficient time to let the hydro- 



LECTURE OX NITER OR SALTPETER. 159 

gen be displaced by the niter gas, then we replace 
the charcoal, get a good heat, cherry red, being 
always careful to protect the rubber stoppers in T 
and T' by guarding shields and dropping water, 
and again after some minutes' wait, we connect the 
rubber tube 6 with the bell jar B. In the position 
as shown in the figure there will be suction through 
the chain of apparatus as soon as the stopper 8 is 
opened, owing to the difference of level, k, between 
the water inside and outside the bell. Therefore all 
stoppers and connections must have been made air- 
tight, otherwise air will be sucked into the appara- 
tus : The true nature of nitrogen will be masked. We 
maintain the action until B is filled with gas, or 
until several holders shall have been filled. 

Properties of nitrogen. After having been pro- 
duced, as just stated, the gas possesses the characters 
of an element. With present means, it cannot be 
further split. A gas devoid of color, odor, taste. 
Specific gravity 14 (H = 1) ; 0.9674 (Air 1). 
This specific gravity is so nearly the same as that 
of the azote, the nonrespirable part of the air, this 
being 0.9713, that we are justified in declaring azote 
= nitrogen, because the nitrogen also is nonrespir- 
able, it causing death by suffocation. The gas is but 
very slightly soluble in water, it is not absorbed by 
the alkalies. It is very indifferent towards all 
agents, and yet it is evident that under certain con- 
ditions it may be made to unite with oxygen in 
several ratios, and also with hydrogen giving rise to 
a most interesting body. Nitrogen we shall find in 



160 CHEMISTRY SIMPLIFIED. 

all animal and plant bodies, constituting the essen- 
tial constituent of protoplasm, the body which is at 
present taken to be the basis, the substratum of all 
life. It is important to note that nitrogen has no 
property by which we can at once identify it, ex- 
cept the specific gravity ; all other properties are 
mere negations of the properties possessed by other 
gases. 

Properties of the spirits of niter and its quantitative 
composition. Acting with the spirits of niter upon a 
metallic oxyd (MeO) we get water + niter. The 
most suitable metallic oxyd for our present purpose 
is lead oxyd PbO which has the pale yellow color ; 
the red oxyd is not equally suitable. Acting upon 
Na(OH) or K(OH) we restore the original niter, 
either soda niter, or potash niter and water. There 
is only one salt formed, no acid salt having been 
obtainable. Hence the radical contained in the 
spirits is there combined with one H, the radical is 
a monad, and will, therefore, be represented by the 
symbol 

H(N m O) 

Hence, also, if we act with the spirits upon lead 
oxyd, the reaction must be 

PbO + 2H(N m O) = Pb(N m O) 2 + H 2 0. 

Like the soda and potash niter, the lead niter con- 
tains no water, except a trifle with the mother 
liquor. The white or colorless crystals of this lead 
niter are rhombohedral, hence isomorphous with 
the soda niter. It is best, because most rapid, to 



LECTURE ON NITER OR SALTPETER. 



161 



use the spirits diluted, because the lead niter is not 
soluble in the concentrated spirits. When all of 
the lead oxyd is thus dissolved, or when the liquid 
will not further dissolve the oxyd, filter and evap- 
orate the filtrate to complete dryness. The residue is 
then pure lead niter. Heated in a crucible or glass 
tube, the lead niter breaks up into brown gas and 
yellow lead oxyd. The brown gas is very acrid 
and suffocating, yet it will act upon a glowing taper 
like oxygen. In fact we can readily prove the 
brown fumes to have an admixture of oxygen ; 
therefore 

Pb(N m O) 2 + heat = PbO -f brown gas + 0. 
This action opens the way for a quantitative deter- 
mination of the ratio existing between Pb, N and 

FIG. 45. 




0, if we arrange the conditions of the experiments 
in such a way that the volume of nitrogen can be 
accurately measured, which results from the decom- 
position of say one gram of the lead niter. 

Let T, Fig. 45, be an ample hard glass tube fitted 
11 



162 CHEMISTRY SIMPLIFIED. 

with stoppers. 8 is a porcelain boat containing 0.5 
gram of lead niter. 9 is a clean roll of copper 
gauze. 7 is a U-tube filled with pieces of pumice 
and H 2 S0 4 (to retain moisture). 6 is a smaller 
U-tube with enough H 2 S0 4 to form a trap. H is 
the holder filled with lime gas and the water in B 
furnishes the pressure to drive out the gas from H. 
10 is a gas burette and 11 the cylinder to regulate 
the pressure. Both cylinders are filled with solu- 
tion of sodium hydrate. All stoppers and connec- 
tions being tight, we first displace all air from the 
apparatus, because four-fifths of it are nitrogen ; 
then heat the copper gauze to redness, while we 
protect the boat from the heat by the shield 12. 
When the gauze is glowing we move shield 12 to 
the left, from time to time, so that the decompo- 
sition of the lead niter shall be slow and gradual ; 
but at length the entire tube is at redness up to the 
shield. As the niter decomposes the oxygen goes to 
the copper and the nitrogen passes into the burette, 
pushing before it the lime gas. As soon as the con- 
tents of the boat are pure dark yellow or red, we 
open the stop cock 4- and drive all niter gas into the 
burette. Then, closing the latter's stopcock, we 
shake the gas with the liquid, thus absorbing all the 
lime gas into the Na(OH) solution, and then read 
the volume of gas. Let V cubic centimeters be the 
volume of the gas, measured under the pressure of 
the atmosphere at 20 C, the pressure of the at- 
mosphere, measured by the mercury column of the 
barometer, be B millimeters. As the gas is satur- 



LECTURE ON NITER OR SALTPETER. 163 

ated with aqueous vapor, being over water, i. e., a 
dilute solution of Na(HO), the tension T of the 
aqueous vapor increases the pressure B and must 
therefore be subtracted, because we wish to get at 
the volume of the di~y gas. The expansion of the 
air for one degree C. is 0.00367 of its volume, hence 
the volume V of dry gas at C. and sea level bar- 
ometer, 760 mm., will be 

V'.(B T) 

= (1 + 0.00367t) X 760 = 

(The tables calculated by Prof. Leo Liebermann are 
most convenient in such calculations.) If the weight 
of one c.c. of dry nitrogen at C. and 760 mm. be 
0.001256 gram, then 

V X 0.001256 = G, 

will be the weight of the nitrogen contained in 0.5 
gram of lead niter, Pb(N m O) 2 . G equals 0.0423 
gram and the weight of lead oxyd, PbO, is 0.337 
gram (found by weighing boat after operation). 
Then we will have 

PbO = 0.3370 

N = 0.0423 } = 0.163 gram == wt. of the N. 

= 0.1207 / oxyd. 

0.5000 - 

The weight of oxygen if found by difference. The 
volume weights of oxygen and nitrogen (found by 
direct weighing) are 16 and 14. Hence we will ob- 
tain the atomic ratio of the two elements by divid- 
ing gram weights of N and by 14 and 16 respec- 
tively. 



164 CHEMISTRY SIMPLIFIED. 

2^23 =0 .00302; -2^07 = 0.00754 I 

14 16 

302 2 

754 - = 5> hence N2 5 

We have directly proved that lead niter is a combi- 
nation of the oxyd PbO with the oxyd N 2 6 . 
Above we showed the probability of the radical 
N m O p being a monad. In the lead niter there are 
then two molecules of the nitric radical. 

PbO.N 2 5 becomes Pb(N 2 6 ) or Pb(N0 3 ) 2 . 
For the sake of uniformity we will designate here- 
after the niters by the word nitrate, thus : 

Hydrogen nitrate = H(N0 3 ) = nitric acid = aqua 
fortis. 

Sodium nitrate = Na(N0 3 ) = soda niter = Chili 
niter. 

Potassium nitrate = K(N0 3 ) = potash niter = 
common niter. 

Calcium nitrate = Ca(NO 3 ) 2 . 

Silver nitrate Ag(N0 8 ). 

Lead nitrate = Pb(N0 3 ) 2 . 

Copper nitrate = Cu(N0 3 ) 2 . 

Ferric nitrate = Fe(N0 3 ) 3 . 

All normal nitrates are soluble in water, whilst some 
sulfates, some chlorids, bromids, iodids, fluorids are 
insoluble in water. 

Sol. Ag(N0 3 ) + sol. NaCl = insol. AgCl + sol. 
Na(N0 3 ). 



LECTURE ON NITER OR SALTPETER. 165 

Sol. Pb(N0 3 ) 2 -f sol. Na 2 (SO 4 ) = insol. Pb(S0 4 ) -f 

sol. 2Na(N0 3 ). 

These two reactions serve us as tests for soluble chlo- 
rids and sulfates respectively. 

Of all bodies we have investigated, the nitrates 
appear to me the most wonderful. The very same 
elements in which we breathe and lead a more or 
less harmless life, the existence of which elements 
we are not even ordinarily aware of, become vio- 
olently active in the form of nitrates. The chlo- 
rates, though acting similarly, are not so astonish- 
ing, because in them we find chlorine, a violently 
offensive body by itself. A rather rough simile 
may bring nearer to your grip of imagination this 
action of the nitrates. Let the atoms be imagined 
as spiral springs (watch spirals). In the atmos- 
phere the nitrogen molecules lie alongside of the 
oxygen molecules as uncoiled springs, inert, inoffen- 
sive things. A powerful shock strikes the inert, 
uncoiled bodies, say the electric spark of a thunder 
storm ; the shock causes the springs to coil up, and 
the affinity of a strong basic oxyd, as K 2 0, Na 2 0, lies 
handy as a binding rope of the springs, as shown in 
Fig. 46 ; the nitrate molecule is achieved ; the poten- 
tial energy of the coils is restrained by the thin 
band of affinity. Now let the nitrate molecules be 
brought into intimate contact with other molecules 
which possess a stronger affinity for oxygen than 
the nitrogen, for instance, carbon molecules, at a 
red heat. We may even carry the picture further 
and say the thermic energy expands the springs, 




166 CHEMISTRY SIMPLIFIED. 

straining them against the restraining bond until 
at red heat this bond snaps, giving way to carbon 
oxygen attraction. With the breaking of the 

FIG. 46. 



Na-K-Ca 



bond, the oxygen springs uncoil and display an 
extraordinary energy, such as we are forced to ad- 
mire in gunpowder. 

COMPOSITION OF GUNPOWDER OR BLACK POWDER. 

We saw in a small experiment how the mixture 
of niter and charcoal powder flew out of the glass 
tube with a flash. The products of that action were 
Na 2 (C0 3 ), sodium carbonate, N, nitrogen and 
CO 2 . The two latter gases, through their expan- 
sion, impart to the explosion its propelling or its 
tearing, splitting effect. The more gas, the greater 
the effect from a given mixture. But in forming 
Na 2 C0 3 much gas passes into the solid state and 
lessens the effect of the powder. It was soon found 
that a greater effect could be obtained by mixing 
with niter and charcoal a certain quantity of sulfur. 
This was all arrived at by those patient experi- 
menters without knowing even that the production 
of gas was the chief object. They mixed sulfur 



LECTURE ON NITER OR SALTPETER. 167 

with the powder on general principles that it would 
be a good thing, because sulfur was a very peculiar 
and mysterious body. We modern chemists, who 
experiment less and think more, know why the sul- 
fur increases the effect. This is the theoretical pic- 
ture of the explosion : 

2K(N0 3 ) + S + 3C -f red heat = K 2 S(solid) + 

2N + 3C0 2 . 
By weight 
2(39 + 14 + 48) -f 32 -f 3 X.12 = 2 X 39 + 32(solid) 



202 +32+ 36 = 110 

+ 2x14 + 3(12 + 32) 

+ 28 + 132 

KNO 8 = 202 = 74.81 % 75 potassium niter 

S = 32 = 11.85 12 sulfur 

C = 36 = 13.34 13 fine charcoal 



270 100.00 

On the second side of the equation stand 
K 2 S ==110= 40.70^ (solid) 41 solid 
2N = 28- 10.40 f. gas 10 



3C0 2 =132= 48.90 <& gas ^ 



270 100.00. 

59 per cent, of the powder is converted into gas. 
One gram of the powder gives by the explosion 0.1 
gram of nitrogen, 0.49 gram of carbon dioxyd. At 
C. and 700 mm., 0.001256 gram of nitrogen occu- 



168 CHEMISTRY SIMPLIFIED. 

pies the space of one c.c.; 0.1 gram of nitrogen occu- 
pies the space of 79.6 c.c. 0.001977 gram CO 2 
occupies the space of 1 c.c.; 0.49 gram CO 2 the space 
of 247.3 c.c. The volume of gas produced by the 
explosion of one gram of perfect black powder is at 
C, 247.3 + 79.6 = 326.9 c.c. One gram of best 
powder, in small but perfect angular grains, occu- 
pies the space of 0.9 c.c.; the surface of 1 c.c. being 
six square centimeters. Hence if one gram of such 
powder be filled into a cartridge and a bullet be 
pressed tightly upon the powder, a space will be 
filled possessing six times 0.9 5.4 square centi- 
meters. After explosion this same space will be 
filled with 326.9 c.c. of gas which will press upon 

326 9 
the enclosing surface with Q Q 363.2 times the 

pressure of the atmosphere or upon 1 square centi- 

363.2 
meter with ^ * = 67.26 atmospheres. But there 

is another very important factor ; the heat gener- 
ated by the explosion, which expands the gas merci- 
lessly, and if the enclosure be rigid, exerting an 
ever-increasing pressure. The gases expand, within 
certain limits so nearly alike, that one coefficient 
answers for all. This coefficient is yfs or 0.00367 
volume for 1 C. By the following reasoning we 
arrive at the theoretical temperature produced by 
the explosion of one gram of powder : 1 gram car- 
bon through the oxydation into CO 2 produces heat 
equal to 8050 calories (the heat would raise the 
temperature t of 8050 grams of water by one de- 



LECTURE ON NITER OR SALTPETER. 169 

gree C. Hence 0.13 gram of carbon will produce 
8050 X 0.13 = 1046 calories. By the burning have 
been produced 0.49 gram of CO 2 , 0.1 gram of N and 
0.41 of K 2 S. Each of these bodies has a capacity 
for heat to be swallowed up before the heat can be 
felt. The temperature, the sensible heat, must 
therefore be directly proportional to the absolute 
heat the 1046 calories, and inversely to the ab- 
sorbed heat. In a general way 

A 

T _ fz 

a 

in which A = absolute heat, a = weight of pro- 
ducts into their respective specific heats. 
In our special case 

TO _ _ 1046 __ 

0.499 X 0.22 -f 0.1 X 0.24 + 0.41 X 0.4 

1046 1046 



0.108+0.024+0.164 0.296 

The a in the denominator is represented by the sum 
of the products of the combustion of the powder ; 
each member multiplied by its factor representing 
the unit of heat capacity or specific heat. 

Thus it is seen that by the combustion of one 
gram of powder a temperature is generated equal to 
3534 C., higher than that of an intense coal fire. 
At this temperature the 326.9 c.c. of gas must have 
expanded to 326.9 X 0.00367 X 3535 = 4236.6 c.c., 
to 12.9 times their volume at C., or 871.7 atmos- 
pheres pressure per sq. cm., provided the law of ex- 
pansion holds good at such high temperature, but 



170 CHEMISTRY SIMPLIFIED. 

this is by no means certain. At any rate, the theo- 
retical picture gives a measure for the actual phe- 
nomenon. We see that the pressure of the gas must 
be enormous, though less than the theoretical, in 
fact only about J as shown by actual experiment, 
made for the military departments of several gov- 
ernments. Such experiments are known by the 
adjective ballistic (made with a ball). The reasons 
are several. In the first place the burning of the 
powder is never complete. 2. The reactions are not 
quite like the formula indicates. A part of the 
oxygen remains fixed by forming K 2 S0 4 , hence 
some of the carbon only burns to CO, whilst some 
of the nitrogen remains as NO. 3. The material of 
the apparatus a gun for instance, or a mortar is 
somewhat elastic. 

As engineers we should know all that has here 
been given, to understand the effects of the blasting 
powder we use. I give you only the chemical facts 
connected with the matter. 

Other powders. The white and smokeless powders 
all contain a nitric radical, either NO 2 or NO 3 . In 
principle there is no difference between them and 
black powder. Their special compositions will be 
dealt with under the subject of carbon compounds. 

INVESTIGATION OF THE BROWN FUMES OR NITROUS 

FUMES. 

These always form, when H(N0 3 ) acts upon an 

oxydizable substance, as copper for instance, or SO 2 . 

Acting with H(N0 3 ) upon copper in a test-tube 



LECTURE ON NITER OR SALTPETER. 171 

we observe the tube filled with the brown fumes so 
long as the action continues. But if the tube be 
stoppered with a narrow tube for the escape of the 
gases, a different action ensues. We notice that the 
gas inside the tube turns lighter by degrees, at last 
being quite colorless, but at the mouth of the escape 
tube a steady cloud of dense, brown-colored gas is 
visible all the time. This at once suggests the pres- 
ence of two different gases within the brown fumes. 
More precisely we would say : Through the action 
of HNO 3 upon an oxydizable body is generated a 
colorless gas an oxyd of nitrogen. When this 
gaseous oxyd comes together with air the brown gas 
forms by combination of the air-oxygen with the 
colorless gas ; but the brown gas itself must possess 
a ratio of oxygen to nitrogen less than 5/2, for if it 
is absorbed in ice water we find produced a mixture 
of spirits of niter and the same acid that was made 
by acting with H 2 S0 4 on the residue left after heat- 
ing niter. All this will be proved presently. The 
brown gas becomes colorless if mixed with an oxy- 
dizable body, as SO 2 for instance, evidently by loss 
of oxygen. Hence the colorless gas must have an 
oxygen to nitrogen ratio less than the brown gas. 

Nitrogen dioxyd, NO 2 or N 2 4 , hyponitric anhy- 
drate the nitrous fumes. Let the tube T, Fig. 47, be 
partly filled with dry lead nitrate and placed in 
furnace F. Make the U-tube U from a J" tube, 
draw it out into a capillary at C, a and 6, then sur- 
round it in the basin B with a mixture of ice and 
coarse common salt ; stick a thermometer t into the 



172 CHEMISTRY SIMPLIFIED. 

mixture. If the salt be kept on snow or ice until 
its temperature falls to C., and if it be then mixed 
with one volume of snow or fine-cut ice, the tem- 
perature of the basin will drop to 20 C. Make 

FIG. 47. 




connection at C with T, and heat T to redness grad- 
ually. We know from previous experiment (com- 
position of N 2 5 ) that the Pb(N0 3 ) 2 breaks up into 
PbO -f- brown fumes. Thus 
Pb(N0 3 ) 2 -f- heat = PbO + (N m O- x ) brown fumes 

+ (6 p x 1)0. 

Passing into U the fumes condense into a brown 
liquid and at 6 issues a gas which sustains combus- 
tion with energy (oxygen). At end of decomposi- 
tion close U at C and a with the blow-pipe. If the 
U-tube be changed twice, then you find in the third 
tube colorless crystals. These represent the true 
substance. The crystals melt at 12 C. to a color- 
less or slightly yellow liquid. It follows that no 
crystals result if the temperature of the freezing 
mixture be not at the least 15 C. As the liquid 
is heated by the warmth of the hand it becomes 
more and more highly colored, giving out dense 
brown fumes and reaches a constant boiling-point 



LECTURE ON NITER OR SALTPETER. 173 

at -j-22 C. (in the hand, because the temperature 
of the blood is 33 C.). On the addition of ice 
water drop by drop, the liquid turns first green, then 
blue, then colorless. It acts upon oxydizable bodies 
more energetically than HNO 3 , because the restrain- 
ing bond of the hydrogen is removed. Mention has 
already been made of the suffocating action of the 
brown fumes. The living organism tries to avoid 
the danger lurking in the breathing of the gas, 
for the muscles of the epiglottis contract instantly 
when the gas comes in contact with their nerve 
ends. At Berlin, some years ago, fire broke out in 
the yard of a large chemical works. Sixty carboys 
of aqua fortis were stored under one shed. They 
exploded, one by one. The acid flowing into the 
straw and wood of the packing let out an immense 
volume of brown fumes. Five of the firemen who 
had been endeavoring to save the carboys, went 
back to the station with the others, smoked a pipe 
and went to sleep in their bunks. Within a few 
hours they woke in convulsions and died shortly 
after, in great agony. Let this be a warning to be 
careful. Do not act upon metals, or sulfids with 
HNO 3 , except in a well-drawing hood; for even if 
death does not ensue, there may be permanent in- 
jury to the bronchise and their capillary ramification 
in the lungs, from ulceration of the mucous mem- 
brane. The composition of the brown gas we find 
similarly to that of the lead niter. We make a small 
U-tube U, Fig. 48, drawn out into capillary thread 
at a, b. We take the weight and then fill into it a 



174 CHP:MISTRY SIMPLIFIED. 

few drops of the liquid, by pressure or by suctioD. 
In T there is the coil of copper wire. At B is the 
burette for measuring the gas, filled with solution 
Na(HO), and which is immersed in a dish of water 

FIG. 48. 




when in use. We fill the tube T with lime gas, in- 
sert 7 at b into the stopper and a into rubber tube 
leading to lime gas holder and furnished with 
clamps C; then connect the burette B. We bring 
T up to redness and turn on the lime gas in a gentle 
current. The radiant heat will suffice to volitalize 
the liquid oxyd of nitrogen and the lime gas will 
carry it over the copper gauze. Nitrogen and lime 
gas pass into B and the NaHO solution will absorb 
the lime gas. Thus we get the nitrogen volume 
which we deal with as in the previous experiment ; w 
being weight of oxyd, n being the weight of nitro- 
gen, w n = 0, the weight of the oxygen. Divid- 
ing n by 14 and w n by 16, we get the ratio 

Jl : w ~ n = 1 : 2 = NO 2 or N 2 4 or N 4 8 
14 16 

Some investigators claim the ratio N 4 8 which can 
be interpreted as N 2 3 .N 2 5 a combination of the 
two oxyds, on the ground that when ice water be 



LECTURE ON NITER OR SALTPETER. 175 

mixed with the liquid oxyd it breaks up into the 
two acid bodies: H(N0 2 ), hydrogen nitrite and 
H(N0 3 ), hydrogen nitrate : to wit 
N 2 3 -f- H 2 = 2H(NO) 2 ; N 2 5 + H 2 = 2H(N0 8 ) 
However, this view, which looks at the molecule as a 
polymeric molecule, i. e. } 4 times NO 2 , only applies 
at low temperatures, for Dulong found for the brown 
gas the specific gravity 1.62, and this corresponds to 
\ vol. nitrogen 0.4856 
1 vol. oxygen = 1.105 

L5906 

so nearly 1.62 that we can have no doubt left. The 
new gaseous molecule is surely NO 2 = 2(JN -{- 0). 
1 vol. N -f 2 vols. O = 3 vols., become 2 vols. 
NO 2 ; there is a condensation of 3:2 of 1J:1. 

When the brown fumes are passed into H 2 (S0 4 ), 
the fumes become absorbed, and if the operation be 
continued for a time, colorless crystals form in the 
acid. The crystals are obtained more readily by 
pouring a few cubic centimeters of H 2 (S0 4 ) into a 
small flask and by spreading the liquid, through 
rotation, upon the entire glass surface. If now the 
brown fumes are brought into the bottom of the 
flask, under the rotation the brown fumes become 
absorbed, a crystalline crust resembling ice forming 
all over the flask (inside). The composition is not. 
definitely settled, probably 2H 2 (SO 4 ).N0 2 . The 
reaction is of much economical importance in the 
manufacture of H 2 (S0 4 ) on a large scale and will 
be brought forward when we shall arrive at that 
process. 



176 CHEMISTRY SIMPLIFIED. 

The colorless gas, nitrogen monoxyd, nitric oxyd, NO. 
This body becomes generated whenever H(N0 3 ) acts 
upon oxydizable bodies, metals, metallic sulfids, 
paper, wood, sulfur dioxyd. As soon as it comes 
into contact with the air it changes into nitrogen 
dioxyd NO 2 (brown nitric fumes). We obtain this 
gas very pure by passing SO 2 into warm HNO* -f 
water. 

In flask F, Fig. 49, we generate SO 2 from the 

FIG. 49. 




mixture M, which is copper gauze and H 2 S0 4 , 
heated by a flame, according to equation 

Cu + 2H 2 (S0 4 ) = CuSO 4 + 2H 2 + SO 2 . 
Through tube 1 gas passes into the washing tube #, 
partly filled with H 2 (S0 4 ) (moisture is retained and 
flow of gas can be regulated). IF is a so-called 
Will's condenser, possessing the three bulbs, 5, 4, 5, 
and containing 2H(N0 3 ) -f 2H 2 0. B is a basin 
holding warm water to heat the H(N0 3 ); through 
tube 6 the gas can be delivered into any suitable 
vessel. In the figure this vessel is a knee-tube T 
filled with mercury and standing in mercury trough 
Q. T is held by stand S. When the gas SO 2 bub- 
bles into the H(N0 8 ) it becomes oxydized into 



LECTURE ON NITER OR SALTPETER. 177 

H 2 (S0 4 ) and H(N0 3 ) becomes changed into the 
nitrogen monoxyd. 

Thus 3S0 2 + 2H(N0 8 ) + 2H 2 O = 3H 2 S0 4 + 

2NO (colorless gas). 

Do not think the composition of the gas must be 
NO, because the equation demands it, many stu- 
dents, and even some professors, have that belief. I 
wrote the equation because I know the gas to be 
NO. I could have balanced the equation in several 
other ways, merely by changing the coefficients of 
SO 2 and ofHNO 3 . 

Proof of the composition of nitrogen monoxyd. Sup- 
pose we have allowed to enter into the knee-tube 
T, Fig. 49, about 10 c.c. of the gas and have marked 
this volume by a sticker. Banking upon the known 
maximum of affinity of potassium for oxygen, we 
will introduce, by means of a thin copper wire, a 
piece of metallic potassium at P, and heat the metal 
with a burner. A flash of light and a violent com- 
motion of the gas accompany the act of deoxydation 
of the gas. I must hold the tube firmly, with the 
left hand, to prevent its being raised above the mer- 
cury level in Q. When the tube has resumed the 
temperature of surrounding air we find the volume 
of gas shrunk to exactly J ; hence there is in one 
volume of nitrogen monoxyd J vol. N -f- J vol. 
or made into full units 1 vol. N -f 1 vol. 0, the sym- 
bol of the gas is NO. There is no contraction in 
the union. 

Specific gravity of NO found by weighing 1 vol. 
=-1.0379 (air=l) 
12 



178 CHEMISTRY SIMPLIFIED. 

J vol. N = 0.4856 

j vol. = 0.5525 
L0381 

Calculated specific gravity equal to the experi- 
mental, hence NO represents the molecular volume 
of the gas. 

Properties of NO. The gas cannot occur in nature. 
Why? Because it changes to NO 2 on meeting the 
oxygen of the air. For the same reason we do not 
know whether it has odor^or taste. Does not act on 
litmus paper. Its actions on the breathing organs 
are the same as those of NO 2 , for the same reason as 
above. If the gas be conducted into a solution of 
copperas Fe(S0 4 ) + 7H 2 or Fe(Cl 2 ) + 2H 2 the 
solution turns dark brown, or even inky black. The 
gas is completely absorbed. Distinction from all 
other gases. This reaction enables us to recognize 
and identify a nitrate in an unknown mixture, even 
.very minute quantities of the nitrate. Proceed as 
follows with this test : Bring the unknown solution 
(1 c.c.) into the bottom of a test-tube T, Fig. 50, add 
2 c.c. of concentrated H 2 (S0 4 ) and mix. Then 
take into a glass tube t, which has been drawn out 
to a capillary, a strong solution of copperas (ferrous 
sulfate) Fe(S0 4 ). Lower t into T, so that the, point 
just touches surface of the liquid mixture, and let 
run out a few cubic centimeters. The two liquids 
are then unmixed, in two superimposed strata. 
Within a short time a dark ring will develop at the 
contact of the strata. If no dark ring develops then 
the unknown substance does not contain any nitrate. 



LECTURE ON NITER OR SALTPETER. 



179 



The student should practice this reaction using as 
unknown a solution which was made up from one 
drop of strong H(N0 3 ) and 50 c.c. of water (ap- 
proximately 0.2 per cent. HNO 3 ). 

Nitrites, Na(NO*), K(NO*), Ag(N0 2 ). Di-nitrogerti- 
trioxyd, N 2 0*. Both -Na(N0 8 ) and K(N0 3 ) loose 
oxygen when heated at low red heat and more 
rapidly at bright red heat. Since neither the metal 

FIG. 50. 




nor nitrogen is given off, the ratio between the 
three elements must become changed ; a new body 
forms. This we can demonstrate readily in two 
ways : (1) by acting upon the residue with concen- 
trated H 2 S0 4 when copious brown fumes are given 
off; (Recall that the nitrates + H 2 S0 4 do not give 



180 CHEMISTRY SIMPLIFIED. 

any fumes.) (2) by adding solution of Ag(N0 3 ) to 
the water solution of the residue a white precipi- 
tate falls out, which is not very soluble in water. 
This silver salt does not contain water, and by its 
decomposition we can find the ratio of Ag, N, 0, by 
using the apparatus and method followed with the 
lead nitrate. Let the silver salt, which shall be 
named silver nitrite (note the substitution of the 
letter i for the letter a in nitrate) be Ag(N m QP~ q ) 
then we shall obtain by the decomposition 

Ag(N m O p ~ q ) -f- red heat = Ag + brown fumes. 
Let the fumes be decomposed by copper gauze at 
red heat and you get the nitrogen. 

( N mQp-q) fumes _|_ aCu _|_ re( j h eat = (p_q)CuO + 
(a-p-q)Cu + mN and thus we find : 

Ag : N : 1 : 1 : 2 hence the formula of the 
nitrite is 

Ag(N0 2 ) and similarly must be the Na, K salt 

Na(N0 2 ) 

K(N0 2 ) 
The hydrogen salt cannot be made, it is too unstable. 

Preparing K(N0 2 ). Heat niter in an iron pot or 
crucible to melting heat, then add 2 parts of metallic 
lead for each part of niter. The affinity of lead for 
oxygen helps the decomposition of the niter : 
K(N0 3 ) -f heat + Pb = K(N0 2 ) + PbO 

Molecular weight K(N0 3 ) = 101, atomic weight of 
Pb = 207, hence 1 part niter -f- 2 parts lead, corre- 
spond to theory. In practice, however, the reac- 
tions are not complete. Some lead is apt to remain 



LECTURE ON NITER OR SALTPETER. 181 

unoxydized, some oxygen escapes, the residue is, 
usually, K(NO 2 ) mixed with PbO, KNO 3 and K 2 O. 
Dissolve the fused mass in little boiling water and 
let cool. The PbO will settle, the K(X0 3 ) will 
crystallize. Decant (that is pour off) the liquid and 
evaporate to dryness, finally heat to melting and 
pour into pencil moulds, same as used for NaOH 
and KOH. K(X0 2 ) is a reagent in use for the 
separation of cobalt from nickel, as well as for other 
operations. The salt usually shows an alkaline re- 
action from KOH, can be neutralized with dilute 
acetic acid. 

In the nitrites, we have undoubtedly a peculiar 
oxyd of nitrogen. The radical (NO 2 ) is not that 
oxyd, its reactions are quite different. This oxyd 
is X 2 3 , for K 2 O.X 2 3 = 2K(X0 2 ) 2 . This oxyd 
dinitrogen trioxyd is contained in the brown 
fumes, as gas. It may be condensed at 15 C. 
into a deeply blue liquid, which boils even at the 
freezing-point of water. A blue solution results from 
the action of XO gas upon a solution of H(X0 3 ) in 
water (specific gravity = 1.25) a green solution, when 
the specific gravity is 1.35 (because this liquid then 
contains both X 2 3 and X 2 4 ,(2X0 2 ). The same 
colors result when acids of the given specific gravi- 
ties act upon certain oxidizable bodies. Any one 
not knowing this fact will often waste much time 
trying to find copper (blue nitrate) because he sees 
a blue solution, or chromium because he sees a green 
solution when acting on galena, the lead sulfid, for 
instance. The student should get this information 
by experiment to fasten it the more firmly. 



182 CHEMISTRY SIMPLIFIED. 

If a solution of Na(N0 3 ) or K(N0 3 ) be shaken 
with amalgamated zinc (zinc coated with mercury) 
the solution will then contain nitrite, to be detected 
by the addition of the liquid to starch paste contain- 
ing potassium iodid and some free H 2 S0 4 (dilute). 
The paste turns blue, because 
KI + H 2 S0 4 (dilute) + NaNO 2 = 1 + N aj K(S0 4 )+ 

IPO + NO. 

The rain water from a thunder shower will give 
this reaction, showing that it contains nitrite; azote 
and oxygen have become united by the electric dis- 
charges of the storm. 

Dinitrogen monoxyd, N 2 0, nitrous oxyd, laughing- 
gas. This gas arises when the monoxyd NO is al- 
lowed to stand in contact with easily oxydizable 
substances ; finely divided zinc, iron filings, sulfites 
(Na 2 (S0 3 )), and many others. One-half of the oxy- 
gen is removed, or 2 molecules NO furnish one 
molecule N 2 0. 
Thus 2NO + Zn = N 2 + ZnO 

2NO -f Na 2 (S0 3 ) N 2 + Na 2 (S0 4 ). 
We proceed to prove this by acting with heated 
potassium upon the gas in a knee-tube, exactly as 
described for NO. The action is quite as energetic. 
After cooling the volume is the same as before the 
action. Hence one volume gas contains one volume 
nitrogen. Weight of one vol. gas (spec, gr.) = 1.5270 
minus weight of one vol. N (spec.gr.) = 0.9713 

05557 
but 0.5557 is very near L1 p 56 = 0.5528 == J vol. 

oxygen. 



LECTURE ON NITER OR SALTPETER. 183 

Hence the gas is NO* or N 2 0. 

The properties of the gas N 2 are remarkable. It 
was discovered by Priestly in 1776, and Sir H. Davy 
demonstrated its composition. The gas is colorless, 
possesses a faint sweetish taste and slight aromatic 
odor. One cubic centimeter at C. weighs 0.001974 
gram. The gas is quite soluble in cold water. At 
C. one volume water absorbs 1.3 volumes of the 
gas, but at 20 C. only 0.67 volume. A taper burns 
in the gas more brightly than in air, almost as in 
oxygen gas. The gas can be taken into the lungs 
(breathed) without any discomfort. Quite on the 
contrary ; its action when breathed, is that of a 
stimulant. The nerves become excited, the effect 
is similar to that of alcohol and ether intoxication 
ensues, either numbness or acute mania. The effect 
is not by any means alike on all persons. Sir H. 
Davy gave it the name laughing-gas, pleasure gas. 
Its application in dentistry is well known. Dentists 
use it with nervous persons, who are unwilling to 
stand up against pain. Though not quite without 
danger, serious after-effects are less likely through 
its use than through other anaesthetics ether or 
chloroform. The dentists buy the gas in the com- 
pressed state, in copper cylinders. At C. the gas 
becomes liquid under a pressure of 30 atmospheres, 
that means when 30 volumes are compressed into 
the space of one volume, approximately ; 300 litres 
of the gas yield 400 c.c. of liquid N 2 0. When this 
liquid is allowed to evaporate it produces intense 
cold, like liquid air, and part of it becomes solid as 



184 



CHEMISTRY SIMPLIFIED. 



snow. The liquid N 2 boils at -89 C., and be- 
comes solid at -100 C. For use of the dentists 
the compression of the gas is only carried so far 
that about 10 volumes are compressed into 1 vol- 
ume ; which means a pressure of 150 pounds per 
square inch. 

Preparation of the gas on manufacturing scale. The 
salt NH. 4 (N0 3 ), ammonium niter or nitrate, breaks 
up into N 2 and H 2 when heated : 

NH 4./xr 3) + heat = N 2 + 2H 2 0, 
and thus furnishes an excellent raw material. It 



FIG. 51. 




is not expensive. Apparatus as shown in Fig. 51 
will enable you to make the gas quickly. R is a 
small retort, into which has been put the ammonium 
nitrate at A. The stand S holds the retort. L is a 



LECTURE ON NITER OR SALTPETER. 185 

Liebig condenser with the water inflow at i and its 
outflow at o. The condensed water and the gas 
separate in the flask C, the gas passes into the dry- 
ing tube D and issues dry at G, whence it may be 
conducted into any desired holder, or to a compress- 
ing pump. Substitute large iron vessels for the 
small glass vessels and you have the manufacturing 
plant. 

Recapitulation of the oxyds of nitrogen : 

N 2 5 (contained in the nitrates) does not exist in 
free state. 

N 2 4 (contained in the very unstable hyponi- 
trates) brown fumes. 

N 2 3 (contained in the nitrites) blue liquid in 
free state. 

N 2 2 (forms no salts) originator of brown fumes. 

N 2 (forms no salts) laughing-gas. 
Nitrogen shows five different valences, from inono- 
to penta-valent, v but all of them are weak. With 
other elements similar tendencies are observed, the 
smaller the affinity between two elements, the 
greater the number of combinations into which 
they enter. 



CHAPTER XL 

AMMONIA, A VOLATILE ALKALI. A COMPLEX 
METALLIC RADICAL. 

AMONG other facts concerning the action of KOH 
and NaOH, we gathered that these hydroxyds and 
their water solutions can dissolve zinc with the evo- 
lution of hydrogen ; when the hydrogen is thus 
generated we say it is in the nascent state, meaning 
by this word (literally " being born ") that there is a 
special force or energy connected with it, and which 
the gas has lost after it is once set free and allowed 
to collect or to dissipate. It is a play of the affini- 
ties. We observe that a solution of indigo is not 
decolorized by shaking it with hydrogen gas. Yet 
when zinc, dilute sulfuric acid and indigo are 
brought together, the liquid becomes colorless. 

Blue indigo + Zn + H 2 S0 4 + water = white in-' 
digo -}- Zn(S0 4 ) + water. Hydrogen is not evolved 
until all the blue indigo is changed into white in- 
digo, and we ascribe the change to nascent hydrogen. 
Thus also when niter, NaHO, and zinc act together, 
the escaping gas possesses not only a peculiar odor, 
but the gas turns red litmus to blue. There must 
be with the hydrogen a new volatile body which pos- 
sesses the properties of the alkaline hydroxyds. Let 
this, as yet suspicious, body be named ammonia. 
(186) 



AMMONIA, A VOLATILE ALKALI. 187 

Passing the gas into water, the latter soon acquires 
alkaline reaction and the power to neutralize acids. 
If these neutralized acids be evaporated, crystals 
form, characteristic for each acid, the same as if 
those acids had been neutralized by KOH. Yet if 
these crystals be heated over an open flame, they 
will completely disappear, totally differing from any 
of the metallic salts. The total volatilization is 
proof that the body, which here takes the place of a 
metal, cannot contain either zinc or sodium, and 
since besides these, only the elements X, 0, H had 
been in the generating solution, they alone can con- 
stitute the new body. Hydrogen we know to be a 
metal, because it takes the place of a metal in the 
salts, producing the hydrogen salts or acids. Oxy- 
gen and hydrogen together form water, which can 
take the place of a metallic oxyd, but not of a metal, 
hence we must conclude that the new body must 
contain nitrogen. 

Investigation. The first step will be the prepara- 
tion of a sufficient supply of the ammonia gas. A 
word about the name. We know that the name of 
the Egyptian sun god was Rha Ammon; also that 
the name of a powerful tribe of Bedouins in the 
desert to the southeast of the Dead Sea, in Palestine, 
was Beni Ammon, in Hebrew, the sons of Ammon, 
as we would say the sons of the sun. It is my be- 
lief that the name ammonia is connected in some 
way with Rha Ammon, though I cannot say how. 
The Egyptian priests must have known this body, 
and for its revivifying, penetrating odor likened it 



188 



CHEMISTRY SIMPLIFIED. 



to the effect of the sun's rays. There is no histor- 
ical record in existence to substantiate my view. 
In the Latin translation of Gebers works (ninth 
century A. D.) the name appears sal armeniacum, 
which would mean the salt of Armenia, but that 
stands also for rock salt. I believe it is a mis- 
spelling. 

Preparation of ammonia. Put into a 500 c.c. flask 
(Fig. 52) 25 grams of NaOH, or about that much, 

FIG. 52. 




75 c.c. of water, 20 grams of zinc (in turnings), a 
piece of bright sheet-iron, and 5 grams of niter. 
Stopper the flask and connect by rubber tubing 
with a Will's condenser. The flask should stand 
on a tripod upon wire gauze. Heat gently and keep 
up a slow evolution of gas. The condenser is 
charged with 20 c.c. of water and 5 c.c. of HC1 con- 
centrated. It is best to place a tube, T, between 
flask and condenser to receive any liquid spatter- 
ings. Will's condenser is especially adapted, be- 



AMMONIA, A VOLATILE ALKALI. 189 

cause either of the bulbs, a, 6, can hold more than 
the volume of liquid indicated, hence no danger of 
the running back of the liquid into T should a 
vacuum occur in F, nor a running out at C should 
the escape of gas become tumultuous at any time. 
The addition of some litmus to the liquid in W is 
advisable ; so long as the color remains red we know 
that the liquid is still able to take up more ammo- 
nia. Any hydrogen mixed with the ammonia will 
escape at the point, C, of the condenser. The action 
must not be overhurried. In hurrying much more 
hydrogen escapes, doing no work. As soon as all 
the air is displaced from F, T, and W, you will note 
a tendency of the liquid in W to advance against 
the gas, to pass up into the bulb, a, an action which 
indicates the strong affinity between ammonia and 
HC1. It will take several hours to accomplish the 
complete change of the niter into ammonia. To- 
wards the end it will be well to set T into a glass 
containing boiling water to drive out the ammonia 
from the liquid which may have been condensed in 
T. Then empty liquid from W into an evaporating 
dish, and evaporate over a water-bath. A white, 
granular residue will be obtained composed of cubic 
crystals like those of common salt, NaCl or KC1, 
which is another indication that ammonia must be 
a body similar to Na and K. We will name this 
white salt ammonium chlorid = Am.Cl. In the 
drug trade it is named sal ammoniac. Bringing this 
salt together with Na(OH) or K(OH) or Ca(HO) 2 we 
observe at once a pungent odor of ammonia. 



190 



CHEMISTRY SIMPLIFIED. 



K(OH) + Ara.Cl = KC1 + H 2 + Ammonia. 
It follows from this action that there must be con- 
tained in the salt one hydrogen besides the ammonia. 
Important observation to be remembered. Of the 
three hydroxyds the one best servicable for making 
ammonia is Ca(HO) 2 . Why? Because it is a 
powder. Even better is the oxyd CaO, because if 
an excess of it be added, then this excess will retain 
the water in the form of Ca(HO) 2 . Even by rub- 
bing together Am.Cl and CaO, ammonia is set free. 
The process follows along the equation 
2Am.Cl+2CaO=CaCl 2 +2 Ammonia+CaO.(H 2 0) 
Pure dry ammonia gas results. 

COMPOSITION OF AMMONIA. 

Let the generating apparatus be set up as shown 
FIG. 53. 




in Fig. 53. In the small flask (not more than 100 
c.c.) put the mixture !/(4CaO+lAmCl) so that the 



AMMONIA, A VOLATILE ALKALI. 191 

bulb is nearly full. To insure perfect dryness of 
the gas, let it pass through two U-tubes U and U 
both filled with pieces of burnt linie, pea size. 

Proof that ammonia contains hydrogen. Rig" a 
hard glass tube T, \ ff diameter, 12" long, as shown 
in Fig. 54. Between two asbestus plugs b and b r 
fill in coarse copper oxyd and ignite both asbestus 
and oxyd thoroughly, before filling the tube. Let 
the plugs be 3 to 4 inches apart. Arrange shield S so 
that only the filled part becomes heated, the empty 



FIG. 54. 

S 

n 


= 


B 

k 


V^ 


fell r " I. ^ 


/'U 


JL__mj_ ^ ^ 


4 IT I 1 V 



part projecting beyond the shield. Fill the tube 
with ammonia gas by attaching t to P in Fig. 53. 
Then heat a to redness, and let the gas pass slowly 
(by heating generating bulb very gently). Soon we 
see moisture appear in the cool tube at TF. Mean- 
while connect the outlet of T by means of a bent 
tube with the test-tube B, which stands inverted in 
basin Cboth filled with dilute H 2 (S0 4 ). Whatever 
gas collects in B must be nitrogen (prove by its 
negative actions), because any ammonia gas passing 
out undecomposed will become absorbed by the 
dilute acid. That the condensed moisture at TF is 
water we prove by bringing together with it a small 
piece of potassium. But water could form only if 
the ammonia contained hydrogen. 



192 



CHEMISTRY SIMPLIFIED. 



Proof that ammonia contains no oxygen. We re- 
place the copper oxyd at. a, Fig. 54, by a bright 
copper wire, or a strip of bright copper foil and 
repeat the experiment at red heat. The copper does 
not cover itself with a film of oxyd. This is proof of 
the absence of oxygen. 

Hence ammonia must be 



Demonstration that the ratio. ' = -. Let a small 

p 3 

volume of the pure ammonia gas pass into the 
eudiometer E, Fig. 55, over perfectly dry mercury. 



FIG. 55. 



FIG. 56. 



/ ~ 



; 



m 



Dry the eudiometer, inside and outside, most thor- 
oughly, before filling in the dry mercury. A 
eudiometer is a glass tube open at one end, made 
of strong glass, either graduated or not graduated, 
but having two thin platinum wires fused into the 
glass near the closed, or upper, end - - +, so that an 
electric current of high potential may be sent across 
in form of a spark. Let m designate the portion of 



AMMONIA, A VOLATILE ALKALI. 193 

the mercury meniscus after the ammonia gas has 
entered. Then turn on the current which has been 
transformed to high potential by means of a Rhum- 
korf coil. We notice at once an increase in the 
gas volume ; rapid increase at first, but slowing 
down by geometric progression until the maximum 
enlargement of the volume has been reached at 2m 
as shown in Fig. 56. The volume has doubled ; 
the hydrogen and nitrogen are now merely mixed to- 
gether, the energy of the shocks from the sparks hav- 
ing broken the chemical bond. Now let us assume 
that the entire volume of the gas be hydrogen, i. e., 
2 vols., let one vol. of pure oxygen be added, mak- 
ing altogether 3 vols. of gas. Let the spark pass 
between the wires (under proper precautions, that is 
covering the mercury trough with a towel and hold- 
ing down eudiometer with the left hand). Had our 
assumption been correct there would now only be 
contained in tube aqueous vapor and liquid water. 
We must remove this water, because we started 
with dry gas, by bringing into the gas a ball of 
K(OH) fused to a thin, soft wire. KOH absorbs 
water eagerly. A ball of fused CaCl 2 will answer 
also. We watch the gas from time to time and 
remove the drying ball when the volume remains 
constant for a full hour. Since we know that 
nitrogen will certainly be in the residue, we must 
have a certain and unknown excess of oxygen after 
the explosion, for we put oxygen equal to J of the 
total gas H -f- N. Let this excess of oxygen = dO, 
then the residue will be = N -f- dO. Suppose we 
13 



194 CHEMISTRY SIMPLIFIED. 

started with one vol. ammonia gas = 10 c.c. By 
decomposition this became = 20 c.c. By addition 
of one vol. of oxygen = 10 c.c. this became = 30 c.c. 
Now we explode the mixture and remove aqueous 
vapor, and find that 30 c.c. have shrunk to 7.5 c.c. 
Then 30 7.5 c.c. = 22.5 c.c. here disappeared in 
form of H 2 ; f of this contraction was hydrogen, J 
oxygen. 



22 5 

~- = 7.5 c.c. of 

But we had used 10 c.c. of 0, hence d = 10 
7.5 = 2.5; hence N + d = N + 2.5 = 7.5 (gas 
volume after explosion); N = 7.5 2.5 = 5 c.c.; 
hence ratio ~ = = J. The formula of ammonia 
is NH 3 . Into 10 c.c. of H 3 N are compressed 15 c.c. 
H + 5 'c.c. N. Into 1 c.c. of H 3 N are compressed 
1.5 H + 0.5 N, or two volumes are condensed into 
one. 

1 vols. hydrogen weigh gram . . . 0.1038 
\ vol. nitrogen weighs gram . . . 0.4856 

0.5894 

which is the calculated specific gravity or volume 
weight of ammonia, and agreesjairly well with the 
experimental specific gravity of 0.596. The mole- 
cular weight (H = 1) is 14 + 3 = 17. 

The chemical nature of ammonia ammonium. 
Ammonia gas is easily absorbed by water. 1 c.c. 
of water at C. will absorb 1050 c.c. of the gas; 






AMMONIA, A VOLATILE ALKALI. 195 

much heat is produced by the absorption. The re- 
sulting liquid, be it concentrated or dilute, has the 
same pungent odor as the gas. The liquid possesses 
the biting taste of potassium and sodium hydrates. 
Raises a blister on the tongue or lips. The liquid 
is lighter than water ; at + 14 C. its specific gravity 
is 0.8844, and contains 35.0 per cent, of NH 3 . This 
liquid goes in the drug trade by the name aqua am- 
monia or ammonia water. We chemists call it ammo- 
nium hydrate. Because from the actions of this 
liquid towards the acids, we conclude that as soon 
as the gas, NH 3 , comes together with water it com- 
bines with the latter, thus 

NH 3 + H 2 0=(NH 4 XHO)=aram<mmra hydroxyd. 

One hydrogen leaves IPO, and attaching itself to 
NB 3 brings forth the metallic radical (NH 4 ). Here- 
tofore we have only had non-metallic complex rad- 
icals, such as (SO 4 ), (NO 3 ). This radical, (NH 4 ), 
we name ammonium. Note carefully the difference 
in the words ammonia and ammonium, and try not 
to confound them in your speech. Ammonia is the 
real, actual compound, NH 3 ; ammonium the hypo- 
thetical metal, NH 4 . I say hypothetical because 
we have no means at present to isolate it ; in at- 
tempting to tear (NH 4 ) from (HO) we always get 
NH 3 -j- H 2 = ammonia -f- water. And yet there 
is no unproven assumption in chemistry more cer- 
tain than this, that ammonium would show all the 
physical characters of a metal if we could separate 
and condense it, even as hydrogen itself would do. 



196 



CHEMISTRY SIMPLIFIED. 



Indirect or circumstantial proof of the ammonium 
theory. Let us introduce (Fig. 57) into the tube, T, 
over mercury, one volume of dry HC1 and one vol- 
ume of dry NH 3 . The one gas is strongly acid, the 
other strongly alkaline. In order to get the vol- 
umes equal let t be a small tube holding 10 c.c. up 
to the mark m. If t be filled with mercury and 
then held so that the upper rim of the sticker falls 
together with the level of the mercury in the trough, 




V, and if now the gas-delivery tube be brought 
under the rim and the gas allowed to enter until all 
the mercury is displaced, that is, until the bubbles 
come up on the outside, and if we do the same with 
the other gas, then we have measured the gases 
exactly at the same pressure and temperature. For 
the transmission of the gas from t into T we incline 
Tas much as possible, and then with the left hand t is 
inclined in the opposite direction, the open end of t 
shoved under the open end of 1 ; the closed end of 
t is then pressed down, and the entire volume of gas 



AMMONIA, A VOLATILE ALKALI. 197 

passes above the mercury into T. When the two 
gases meet a white cloud forms ; the mercury rises 
and occupies practically the whole of T. Both gases 
have disappeared, no hydrogen has been liberated, 
we have 

HC1 + NH 3 = HCLNH 3 , (sal ammoniac.) 
But the resulting body is a white salt crystallized in 
cubes and octahedrons, or a combination of the two* 
exactly the same as KC1 and NaCl. By action of 
H 2 S0 4 upon this salt we obtain HC1, as we did 
from NaCl and KCL Hence we deduce that a body 
must be in the salt, in every respect equal to either 
sodium or potassium. That is ammonium, NH 4 . 

HCLNH 3 = (NH 4 ).C1 = AmCl. 
Some chemists always write Am. instead of (NH 4 ) 
in order to lay stress upon the metallic nature of 
the group (NH 4 ). Because one volume HC1 com- 
bines with one volume NH 3 we say ammonium is 
a monad, a monovalent radical ; hence there is 
one nitrate (NH 4 ).(N0 3 ) 

twosulfates / (NH 4 ).H.(S0 4 ) acid sulfate, bisulfate 

3 I (NH 4 ) 2 .(S0 4 ) neutral sulfate 
one chlorid (NH 4 ).C1. 

Knowing now the composition and nature of ammo- 
nia and ammonium, we can write the equation of 
its formation from Na(OH), Zn, Na(N0 3 ), or K(N0 3 ) 
thus, in two stages, 

(1) 2Na(OH) + Zn = Na 2 Zn0 2 + 2H 

(-2) 2Na(N0 3 ) + 16H = Na 2 + 5H 2 + 2NH 3 



198 CHEMISTRY SIMPLIFIED. 

or 16Na(OH)+8Zn+2Na(N0 3 ) + water = 

8Na 2 Zn0 2 + 4H 2 + 2Na(OH) 

or 8Na(OH) + 4Zn -f Na(N0 3 ) -f water = NH 3 + 

4Na 2 Zn0 2 -f Na(OH) + 2H 2 0. 

The incentive for the action is the tendency of the 
zinc and sodium to form the salt Na 2 Zn0 2 (sodium 
zincate), then the hydrogen in the nascent state attacks 
the niter, substitutes itself for the oxygen and 
changes the latter into H 2 0. A very similar ac- 
tion takes place when zinc is in presence of dilute 
H 2 S0 4 and H(N0 3 ). Here the incentive lies in the 
tendency of zinc to displace the hydrogen in H 2 S0 4 
and to form Zn(S0 4 ). Then the nascent hydrogen 
will attack HNO 3 as in the alkaline solution. Thus : 

9H 2 S0 4 + 8Zn -f 2HN0 3 + much water = 

SZnSO 4 + (NH 3 ) 2 H 2 S0 4 -f 6H 2 0. 
It also follows that a similar action will take place 
when zinc acts upon a very dilute water-solution of 
H(N0 3 ) itself, but in this case only part of the 
nitrogen becomes changed into NH 3 . 
Thus 10H.(N0 3 ) + 4Zn + water = 4Zn(N0 3 ) 2 + 

NH 3 .HN0 3 + 3H 2 0. 

Of 9 molecules H(N0 3 ) only one becomes changed 
into NH 3 . The student must practice on these 
equations specially, because on them depends a 
method, and a very good one it is, to determine in 
an unknown substance the percentage of nitrate and 
nitrite. For it is evident that the action must be 
similar upon nitrites ; one molecule of nitrite re- 
cjuires 2H less for its conversion into NH 3 , Besides 



AMMONIA, A VOLATILE ALKALI. 199 

these, which we may designate as inorganic or 
mineral processes, there are many other processes by 
which ammonia is generated, namely the processes 
of fermentation and putrefaction ; the latter process is 
only a variety of fermentation and often referred to 
as putrid, or stinking, fermentation. 1. Ammonia 
forms in the curing of tobacco. The air-dry leaves 
being made into piles, soon begin to feel warm 
and give out a strong odor of ammonia. The 
nicotin of the leaf which contains much nitrogen is 
broken up by the ferment (a fungus) and the tobacco 
looses its rankness. The chemical reactions are 
complex and could not be understood by you at 
your present state of knowledge. 2. Ammonia 
forms in the fermentation of urine, because this se- 
cretion contains much urea a highly nitrogenous 
substance like nicotine. 3. Ammonia forms in the 
distillation of soft coal ; because the coal contains 
from one to two per cent, of nitrogen ; and although 
one can only get say 20 Ibs. at most of ammonium 
sulfate, by bringing the gases from the distillation 
in contact with H 2 S0 4 , yet so many millions of tons 
of coal are distilled every year, that the total ofj 
ammonium sulfate is enormous, and constitutes inf 
fact the only commercially important source of supply/ 
of ammonia. The great bulk of this goes back to 
the field as fertilizer, to supply the growing crops 
with nitrogen. Much is however consumed chemi- 
cally in the arts and manufactures. Though not 
immediately a subject for the miner or metallurgist, 
yet every engineer ought to be acquainted with these 
sjaort statements. 



200 



CHEMISTRY SIMPLIFIED. 



Ammonia combines with many bodies, among 
others with silver chlorid and calcium chlorid. 
Note this, so that you do not attempt to dry the gas 
by passing through CaCl 2 . On the other hand, we 
may utilize this fact to procure liquid NH S (not 
ammonia water). AgCl is better suited than CaCl 2 . 
Bring the dried, pulverized AgCl into a tube and 
pass over it, slowly, dry NH 3 so long as the latter 
is absorbed. Then bend a strong glass tube Finto 
a knee Fig. 58, and pour the AgCl.NH 3 into this 
tube. Clean the tube at d and draw it out over the 
lamp, making a good strong job. The tube will be 
then as shown at a in Fig. 58. The AgCl.NH 3 lies at 

FIG. 58. 




S. Immerse the pointed end into snow or ice and 
heat S slowly. Soon a colorless, very mobile liquid 
will condense at L; this is liquid NH 3 . The 
liquefaction is, in this case, produced by the self- 
pressure of the gas as it becomes expelled at S. If 
allowed to stand the liquid will disappear because 
the AgCl has once again taken up NH 3 . The ex- 
periment may be repeated over and over. At 40 
C. the gas becomes liquid without any extra pres- 
sure. At 90 C, the liquid turns into a snow- 



AMMONIA, A VOLATILE ALKALI. 



201 



white solid, which melts at 75 C. and has no odor, 
owing to the absence of tension at this low tempera- 
ture. The tension of liquid NH 3 at C. is 7 
atmospheres, and its specific gravity = 0.63 (water 

In the chemical factories aqua ammonia or am- 
monium hydrate is prepared from (NH 4 ) 2 S0 4 by 
means of milk of lime in large iron cylinders C, 
Fig. 59. 

(NH 4 ) 2 S0 4 + Ca(HO) 2 + water+heat = 2NH 3 -f 
Ca(S0 4 ) + 2H 2 + water. It is necessary to keep 




the mixture in constant motion by means of a 
stirring wheel W, the shaft of which passes through 
well tightened stuffing boxes B E' . The manhole 
M serves to introduce materials ; the live steam 
enters at 8; the ammonia gas together with a cer- 
tain quantity of water vapor passed out at A. is 
the discharge opening, and the pulley P transmits 
the power to the wheel W, From A the gas passes 



202 CHEMISTRY SIMPLIFIED. 

through a cooler in which the aqueous vapor also 
condenses and flows partly as gas, partly as highly 
concentrated liquid into glass balloons (carboys), or 
iron cylinders if the liquid is to be shipped into hot 
climates. The carboys must be most carefully 
packed in straw or salt hay, for if a carboy should 
break, the hold of a ship for instance could not 
be entered ; the gas is deadly, causing immediate 
suffocation. 

The concentrated aqua ammonia is much used in 
the Carre ice machine, the construction of which is 
explained in physics. Its principle is that a con- 
centrated solution of ammonia gives out J its NH, S 
as gas, without any water, when gently heated. 1 If 
the gas be taken by a suitable pump and forcpd 
into a strong tube, which is cooled by running 
water, so as to remove the heat of compression, and 
if the compressed gas be allowed to flow into an- 
other tube which is surrounded by water stagnant 
then this water will fall below its freezing-point, 
it will become ice. Why? Because the compressed 
gas in expanding into the tube (from which the air 
has been pumped) will absorb the heat necessary 
for its expansion from the surrounding objects. 
Theoretically no ammonia is lost, because the ex- 
panded gas is again taken hold of by the pump and 
compressed as before. Practically a certain portion 
is lost through unavoidable leakage of the appara- 
tus, and must be replenished. 

The aqua ammonia also serves as raw material 
for the preparation or manufacture of the other 



AMMONIA, A VOLATILE ALKALI. 203 

salts, the nitrate (for the manufacture of laughing 
gas), the chlorid (sal ammoniac), the carbonate and 
the bicarbonate. The latter salts are also known as 
hartshorn salt, because they were formerly obtained 
by distilling hartsliorn or other kinds of horn. It 
has been mentioned that horn and skin as well as 
hair are so-called albumenoid bodies (like albumen 
white of egg) containing from 15 per cent, to 17 
per cent, of nitrogen. Now if the horn be heated 
in a closed vessel, it will char and give off fumes as 
well as gases. Amongst these is the ammonium car- 
bonate, and it may be condensed. 

Both carbonate and bicarbonate evaporate in the 
air, giving a strong odor of ammonia, hence known 
as volatile salt, smelling salts, to be applied to fainting 
persons. Owing to their easy and complete volatili- 
zation, these salts are used instead of baking soda 
in the making of fine cake. Being incorporated 
into the dough (flour, milk, sugar, eggs), the salt 
becomes gas in the oven, raises the dough, and 
leaves neither taste nor smell. 

(NH 4 ) 2 C0 3 = normal or neutral carbonate. 

H 2 0.(NH 4 ) 2 C0 3 .C0 2 = bicarbonate. 
The neutral (NH 4 ) 2 C0 3 is a highly unstable salt. 
As soon as heat is applied it breaks up. The trans- 
parent or translucent crusts which we buy as neu- 
tral carbonate have normally the composition : 

2((NH 4 ) 2 C0 3 ).H 2 C0 3 = sesquicarbonate, or 1J 
carbonate. 

The salt is made by heating together in an iron 
retort ; 



204 



CHEMISTRY SIMPLIFIED. 



(NH 4 ) 2 S0 4 +CaC0 3 (chalk) or (NH 4 )Cl+CaC0 3 . 
Th.e bicarbonate is usually a granular substance, 
but may easily be obtained in long prismatic, ortho- 
rhombic crystals, white or colorless. Composition 
as above, (NH 4 ) 2 .C0 3 .H 2 C0 3 . 

It is prepared by passing lime-gas into a saturated 
solution of the sesquicarbonate. Being less soluble 
than the latter salt, the bicarbonate falls out in 
grains. 

Sal ammoniac, ammonium, chlorid, (NH 4 ).C1. A 
white or colorless salt. Sometimes a loose, fluffy 

FIG. 60. 




powder composed of small cubic crystals. Mostly 
in lumpy crusts, dense, as if they had been melted, 
and exceedingly fibrous, tough ; will not grind into 
powder. To study the formation of this body, place 
two watch glasses alongside of each other, pour into 
the one concentrated HC1, into the other concen- 
trated aqua ammonia, and cover the two with an 



AMMONIA, A VOLATILE ALKALI. 205 

inverted beaker glass or bell jar. Both liquids giv- 
ing out gas, there will be at once a white cloud. 
The glass and table cover themselves with snowy 
sal ammoniac, feathered and fern-like aggregates of 
small crystals. At the point of sublimation or vol- 
atilization the salt breaks up into HC1 + NH 3 . One 
smells both at the same time, but so soon as the 
temperature drops reunion ensues, hence the salt 
can be sublimated in earthenware vessels, glazed, to 
avoid yellow stains. In Fig. 60, a is earthenware, 
b is earthenware, c is a cast-iron vessel into which the 
vessel, a, fits, M is the crude salt, and S represents 
the sublimated crusts of the salt. 

Use of sal ammoniac in soldering. Soldering means 
the joining together of two metal surfaces by means 
of a film of liquid metal (solder) whose melting- 
point is much lower than the melting-point of the 
metals which are to be joined. Solder is either 
hard or soft. Hard solder is an alloy of 2 pts. lead 
and 1 pt. tin ; soft solder contains one lead, one tin. 
The soldering-hammer or iron is a pointed piece of 
copper, the point of which is coated with tin. Tin 
will not stick to heated copper, because the latter 
covers itself with a film of oxyd, as you well know. 
But if the hot copper be rubbed together with the 
tin and sal ammoniac, then the two metals will cling 
together; the tin fairly jumps at the copper. Why? 
Because we have seen that the (NH 4 ).C1 when 
heated breaks up into HC1 + NH 3 . But HC1 at 
once converts the oxyd film into fusible chlorids, 
Cu 2 Cl 2 ; the metals become bright and join. After 



206 CHEMISTRY SIMPLIFIED. 

the hammer is well tinned it will hold liquid solder. 
And if now (NH 4 )C1 in powder be strewn over the 
surfaces which are to be joined (brass for instance) 
the (NH 4 )C1 will cleanse them, the solder will ad- 
here. Liquid HC1 or hydrochloric acid may be 
used, but is inconvenient and not so effective, be- 
cause it evaporates too rapidly. Sal ammoniac is 
used in medicine, and also for freezing mixtures, 
because its solution in water absorbs much heat. 

SOLVAY PROCESS. 

The Solvay process, also known as the ammonia- 
soda process, has become of such great importance 
that we must know something about it. Nearly 
one-half of the world's supply of soda-ash is now 
manufactured by this method. Like many other 
processes, the reactions underlying it were known 
many years before the mechanical difficulties of 
applying them could be overcome. The reactions 
involved here are 

NH 3 + H 2 + CO 2 = NH 4 HCO 3 . 

NaCl + NH 4 HC0 3 == NaHCO 3 + NH 4 C1. 

2NaHC0 3 + heat = Na*CO* + H 2 + CO 2 . 

CaCO 3 + heat = CaO + CO 2 . 

2NH 4 C1 + CaO = CaCl 2 + 2NH 3 + H 2 0. 

The last two equations show the uses made of by- 
products, which help to make the process a com- 
mercial success. 

The equations represent the following operations : 
1. The formation of NH 4 HC0 3 , which immediately 



AMMONIA, A VOLATILE ALKALI. 207 

reacts with NaCl, producing the most insoluble 
combination possible, when CO 2 is passed into 
purified arnmoniacal brine. 2. The calcination of 
the NaHCO 3 to form the normal carbonate, 
Na 2 C0 3 . 3. The decomposition of limestone in a 
lime kiln to produce CaO for by-product recovery, 
and CO 2 for operation 1. 4. The recovery of am- 
monia to be used over again. 

The initial supply of NH 3 is obtained from com- 
pounds that are the by-products of the coal-gas 
works. Ammonium sulphate is the principle com- 
pound used. From the equations one might think 
that only the initial supply of NH 3 would be needed 
for continuous operation ; but leakages have to be 
made up from an outside source. 

The CO 2 is obtained from the lime kilns and also 
from the calcination of the bicarbonate, NaHCO 3 . 
The lime-kiln gases are produced in continuous 
kilns, and are cooled and purified before being 
passed to the carbon ating towers. These gases con- 
tain about 35 per cent, of CO 2 . 

The purified brine is first saturated with NH 3 , 
the heat produced being taken up by cooling coils 
in the tank. The ammoniacal brine is then 
pumped into towers, supplied with perforated 
diaphragms to make good contact between the 
liquid and the CO 2 which is forced in under pres- 
sure. 

The milky liquid drawn out from the bottom of 
the towers contains the NaHCO 3 in suspension. 
This is separated and washed by means of centri- 
fugal machines. 



208 CHEMISTRY SIMPLIFIED. 

The bicarbonate is then calcined in covered cast- 
iron ovens to produce the Na 2 C0 3 , soda-ash. The 
gaseous products are cooled and sent back to be 
used again. The soda-ash produced by this process 
is more fluffy than the Leblanc soda-ash, hence it is 
often recalcined to increase its density. Ordinarily 
the Solvay soda-ash is exceptionally pure. 



CHAPTER XII. 
ORIGIN AND OCCURRENCE OF NITER. 

ALL nitrates being easily soluble in water, we can 
expect to find any of them as mineral only under 
exceptional conditions : that is; in places protected 
against water. Such conditions exist in the rain- 
less parts of North America and South America, 
Asia, and Africa. Europe has no rainless districts. 
But the Continent of Australia might yet prove to 
be a storehouse of niter ; it is hardly explored as 
yet. Nitrates or any nitrogen compounds have 
never yet been found among the rock^forming 
minerals. Thus we are forced to the conclusion 
that the air contains the entire supply of nitrogen 
from which plants draw this element ; store it 
in their structure first as protoplasm, then by dif- 
ferentiation into more complex tissues and com- 
binations as the gluten of the cereal seeds, as nicotine 
in tobacco, as morphine in the poppies and multitudes 
of others. The animals feed upon the plants, build- 
ing up still more complex tissues, such as muscles, 
nerves, skin, hair. These in their turn become 
metamorphosed, changed into matters rejected or 
excreted. Where animals congregate in numbers, 
as in cattle-yards, stables, etc., one notices the soil 
reeking with ammonia and ammonium carbonate 
14 (209) 



210 CHEMISTRY SIMPLIFIED. 

from the fermentation of the excreta. Before long 
a white film appears upon the surface (when dry 
weather sets in): the white film is made up of small 
prismatic crystals of niter. Hence we conclude that 
ammonia and ammonium carbonate become oxy- 
dized in the presence of a sufficiency of an alkaline 
body become nitrates. If the niter film be scraped 
off from time to time, the raw material for the 
manufacture of niter is given in these scrapings. It 
will only be necessary to extract this niter earth 
with water, strain the liquid through cotton or linen 
cloth, and evaporate to the point of crystallization 
and let cool, when the nitrate will form in large 
crystals, mostly colored yellow and known as crude 
niter. By resolution and crystallization, at the last, 
pure niter results. Through this method fully one- 
third of the niter of commerce is still at this time 
made in India, notably in the valley of the Ganges 
in the Kingdom of Bengal. By piling up soil rich 
in humus into heaps or walls, 3 to 4 feet deep and 
6 feet high, and covering these heaps with a shed, a 
so-called niter plantation can be built. A system of 
gutters or pipes distributes the liquid animal excre- 
tion urine over the tops of the heaps, wood ashes 
are strewn over from time to time (to supply the 
potassium), and before long the white niter film will 
appear on the wind face of the heaps. It is scraped 
off regularly ; the extracted earth being always re- 
turned to the heap, and thus a continuous process of 
niter-production becomes instituted. Likewise the 
earth floor of stables was dug up from time to time 



ORIGIN AND OCCURRENCE OF NITER. 



211 



in all the villages of France and the rest of the con- 
tinent of Europe during the Napoleonic wars, to 
supply the niter for the enormous consumption of 
gunpowder. Sweden is the only country where this 
custom still prevails. 

However, the discovery of an extended territory 
in Peru, under the surface of which lies a natural 
deposit of soda niter, has gradually produced a thor- 
ough revolution in the niter industry. The former 
Peruvian Province, Tarapacca, now belonging to 
Chili, is formed by a plateau with an average alti- 

FIG. 61. 




tude of 3,000 feet. It forms the first steps, so to 
speak of the giant stairway of the Andes, the highest 
step of which is 26,000 feet. The surface rocks are 
all of volcanic origin, being both basalt, porphyry 
and trachyte. Between ridges of these rocks extend 
flat basins whose surfaces are destitute of vegetation 
except a few plants which have become acclimated. 
The region is quite rainless, a perfect desert. Fig. 



212 CHEMISTRY SIMPLIFIED. 

61 is a section through a niter basin, s, s gives a 
vertical section of the different layers ; a, top layer 
of ashy gray sand and pebbles, 6, conglomerate 
in which the same material contained in the top 
layer is cemented together with clay and salt, c, 
massive niter, sometimes 8 to 9 ft. thick and perfectly 
white, a mixture of sodium nitrate, sodium chlorid, 
potassium sulfate, sodium sulfate, sodium iodid, 
sodium iodate with more or less fine sand and clay, d, 
pure sodium chlorid (common salt), e, clay and loam, 
/, bed rock-granite, porphyry, basalt. The natives 
give to the niter the name caliche. The mining 
operations consist in sinking bore holes to the sur- 
face of bed e, the clay. The diameter of the hole 
admits a workman of small stature, who widens out 
a small chamber and charges it with 500 to 600 Ibs. 
of powder or a corresponding quantity of dynamite. 
The hole is then filled first with dry, then on top 
with wet, sand. The explosion usually breaks up the 
niter bed in a circle of about 90 to 100 feet in 
diameter. The niter blocks are then sorted out and 
transported to the leaching works some distance 
away. In 1873 the niter bed was estimated to under- 
lie a territory of 550 square miles, and each square 
mile to contain about four million tons of niter, 
which would give a total of 2,200 millions of tons 
or an annual yield of two million tons for a thous- 
and years. But since the present consumption is 
about ten million tons per year, the enormous de- 
posit will not last over 200 years. How came this 
deposit to be? The nitrogen must have been 



ORIGIN AND OCCURRENCE OF NITER. 213 

brought by the instrumentality of either plants or 
animals or both ; our present knowledge admits of 
no other source. As we find the Chincha Islands 
just off the coast of Peru, and upon these islands 
millions and millions of tons of guano, Indian word 
for the excrements of birds, it has been suggested by 
some that this depression or gap in the Andean 
Mountain chain was used in past agesas the transi- 
tion point for the east-west migration of birds and 
they made a halting place on the shores of existing 
lakes (now dry desert). This theory, while account- 
ing for the nitrogen, leaves out the phosphate con- 
tained in the guano. There are no phosphates in 
the niter beds ; phosphates are much less soluble 
than the nitrate of sodium ; they would surely be 
found with the niter if guano had been the source 
of the nitrogen. Equally fallacious is the theory of 
sea-weeds as original nitrogenous material. " We do 



CONVERSION OF SODA NITER INTO POTASH NITER. 

Although Na(N0 3 ) contains more (NO 3 ) per unit 
weight than K(N0 3 ), Na(NO 3 ) being 85, KNO 3 
being 101, yet experiments proved the unsuitability 
of Na(N0 3 ) for gun powder. Thus the conversion 
of Na(N0 3 ) into K(N0 3 ) became necessary. It 
is readily done by the reaction 

Na(N0 3 ) + KC1 = K(N0 3 ) + NaCl. 

Na(N0 3 ) is produced in Chili, KC1 is produced 
(see under potassium) in the salt mines at Stass- 
furt, Germany. Conversion comprises the following 



214 



CHEMISTRY SIMPLIFIED. 



stages or operations : (1) Dissolve the soda niter in 
1.5 parts of boiling water in a large iron vessel or 
open boiler, B (Fig. 62). (2) Dissolve KC1 in three 
parts of water. (3) Hang into B a perforated sheet- 
iron vessel, P, by means of chain, C C, and a crane. 
(4) Add the KC1 to the boiling Na(N0 3 ) solution in 
quantity corresponding to the ratio niter = 85, 
KC1 = 74.5. (5) Common salt, NaCl, will begin to 




fall out at once as a fine, granular body, because it 
is less soluble in the given water than either of the 
two others. (6) NaCl crystals will collect in the 
perforated or basket vessel, P, more and more as the 
liquid is boiled away to one-half. (7) The vessel, 
P, is lifted out and washed with boiling water, 
which displaces the adhering niter liquor. The 
washings are boiled down and added to liquid in B 
This liquid is run into shallow iron pans, where the 



ORIGIN AND OCCURRENCE OF NITER. 215 

impure K(N0 3 ) now comes out as a. massive crystal 
crust as the liquid cools down. (8) The mother 
liquor, being chiefly NaCl with some K(N0 3 ), is 
boiled down, the salt falling into basket as at first. 
(9) The massive, impure K(N0 3 ) is redissolved and 
boiled down until no NaCl falls,, and is then run 
into vats, where it cools under constant agitation. 
The agitation causes the niter to fall-out in small, 
loose crystals like granulated sugar. The niter 
meal is raked and dipped out, thrown upon drying 
floors, and then packed into bags and shipped. 
After this refining process the niter still holds about 
one-half per cent, of NaCl, which does not, however, 
interfere with its further use in powder making. 
The NaCl produced by this process is chiefly used 
for pickling meat, as the small quantity of adhering 
niter is desirable as a better preserving agent even 
than the salt. 



CHAPTER XIII. 

THE MANUFACTURE OF HYDROGEN SULFATE 
OR SULFURIC ACID ON A COMMERCIAL SCALE. 

1. Direct proof that H 2 S0 4 results by the union of 
SO* with H 2 0. Sulfur disappears when heated 
with concentrated HNO 3 . It disappears easier if 
HC1 is also present. If the liquid be then evap- 
orated on a water-bath a point will be reached when 
no further evaporation takes place. Water must be 
added several times and the liquid evaporated to 
get rid of HC1 and excess of HNO 3 . The residue 
has all the characters of hydrogen sulfate. Let the 
action be made with a known weight of the flowers 
of sulfur, say 0.5 gram. Then let us add water, 
after the evaporation and also 3 grams of pure lead 
oxyd (PbO), and let everything be transferred to a 
clean porcelain crucible of known weight, and be 
evaporated to dry ness. We know that lead vitriol 
will stand a low red heat without decomposition, 
and also that lead nitrate decomposes below red 
heat into PbO + 2N0 2 -f O 2 . If then we heat the 
crucible to redness until the weight be constant, we 
shall have the total 3 grams of lead oxyd, the total 
0.5 gram of sulfur and the oxygen which was taken 
up by the sulfur to form the hydrogen sulfate, but 
(216) 



MANUFACTURE OF HYDROGEN SULFATE. 217 

there will be no water, because PbO has displaced 
the water in H 2 O.S0 3 forming PbO.SO 3 . 

We find, after ignition, that the contents of the 
crucible weigh 4.25 grams ; 0.75 gram of oxygen has- 
been taken up by 0.5 sulfur, for 4.25 3.0 0.5 = 
0.75 ; hence %f : - T 7 / = = 0.01563 : 0.0463 ==1:3, 
hence $0 3 . The reaction between sulfur and hy- 
drogen nitrate alone is : S+2H(N0 3 ) + heat = H 2 O 
+ SO 3 + 2NO = H 2 (S0 4 ) -f 2NO. (The HC1 when 
added acts as a catalyzer possibly through the 
momentary formation of a chlorid of S.) Thus 32 
Ibs. of S will yield with 126 Ibs. of H(N0 3 ), 98 Ibs. 
of H 2 (S0 4 ). Value of 1 Ib. S = 0.5 cent; of 1 Ib. 
nitric acid, specific gravity 1.48 7.5 cents. But 
acid of 1.48 specific gravity contains only 88 per 

cent, of H(N0 3 ), hence 1 Ib. of HNO 3 costs 



88 

-8.52 cents. Thus 1 Ib. of H 2 (S0 4 ), if made by 
this reaction would cost in material alone 

for s 32x - 5 =: Q.16 cent 

'126X85 =11.06 cents. 

forH(N0 3 ) J?=10.9 cents 

Jo 

Now, the 66 Be. sulfuric acid which contains 93 
per cent. H 2 S0 4 is sold for 2.5 cents per Ib. or 
nearly J of the 11.06 cents. The oxygen of the 
niter is too expensive for our purpose. Supposing 
we change S into SO 2 , by burning the sulfur in 
air, the oxygen of which costs nothing, and then 
conducting the SO 2 into the H(N0 3 ), then we obtain 



218 CHEMISTRY SIMPLIFIED. 

3S0 2 + 2H(N0 3 ) == H 2 + 3S0 3 + 2NO 
and by adding water 

3S0 2 + 2H(N0 3 ) + 2H 2 = 3H 2 S0 4 + 2NO. 
By this reaction the cost of materials will be cut 
down to ^ or 3.66 cents. Even this is too much. 
But we have seen that the gas NO becomes NO 2 in 
presence of air, and that NO 2 reacts upon SO 2 thus 

SO 2 + NO 2 = SO 3 + NO 

or SO 2 + H 2 -f NO 2 = H 2 (S0 4 ) + NO. 
Deduction : The gas NO can be made the carrier 
of the atmospheric oxygen or even more pertinently 
the transfer agent. This reaction, then, points out 
the road for the cheap manufacture of H 2 (S0 4 ), for, 
theoretically we need only to buy the sulfur. The 
theoretical conditions would become realized in 
practice, if we could burn the sulfur in pure oxygen- 
But the latter requires KC10 3 , and turns out more 
expensive even than the niter-oxygen. The chem- 
ical engineer is forced to make a compromise 
between what is best and what is cheapest. For, 
since 1 volume SO 2 contains 1 volume of oxygen 
we must admit for every volume of sulfur vapor, 5 
volumes of air, hence follows the mixture of 5 
volumes, one of which is SO 2 and four are N. In 
addition to this, 2.5 more volumes of air must be 
admitted to furnish the one-half volume required 
for the transfer by NO so that SO 3 may result. 
Thus 6 volumes of indifferent, or useless, nitrogen 
must be steadily removed from the vessel in 
which the transferring action takes place. This 



MANUFACTURE OF HYDROGEN SULFATE. 219 

cannot be done without at the same time re- 
moving the NO (the transfer agent), while the 
H 2 S0 4 condenses to a liquid and thus removes 
itself. The French chemist Gay-Lussac's ingenuity 
intervened, however, and saved a very large per- 
centage of NO ; and thus made the low price of the 
sulfuric acid possible, while yet leaving a margin 
of profit in the manufacture. Another saving in 
the cost came in with the substitution of pyrite for 
sulfur. The mineral pyrite is FeS 2 and contains 
2 X 32 = 64 sulfur for every 56 of iron, or 1 
pyrite = 0.533 of sulfur, a little more than J its 
weight. As some sulfur always remains with the 
iron, we may say that pure pyrite yields 50 per 
cent, of sulfur in form of SO 2 if properly handled. 
The action occurs thus : 

2FeS 2 + 110 = Fe 2 3 + 4S0 2 , (if complete.) 
240pyrite+176 oxygen=160 iron oxyd-j-256 sulfur 
dioxyd. If burnt in air we have an addition of 4 
vols. of N = 616 nitrogen. These numbers, of 
course mean weight. 1 c.c. of SO 2 weighs 0.00285 
gram hence 



256 grams SO' = - = 89824 c.c. = 89.8 

liters. 

1 c.c. of N weighs = 0.001256 gram, hence 616 
grams 

N = _ _ = 490.4 liters. 
0.001256 

For 1 liter of SO 2 we have about 5 liters of nitro- 



220 CHEMISTRY SIMPLIFIED. 

gen. But we must provide with this also the oxygen 
necessary to make SO 2 into SO 3 . SO 2 contains J 
volume S and one volume 0, hence 1 volume SO 2 
requires J volume of or 2J volumes of air, thus 
making a total of 1 volume SO 2 + 5 volumes of 
N + 2J volumes of air = 8.5 volumes, leaving the 
pyrite burners. In this mixture of gases the volume 
percentage of SO 2 is 11.76. If this percentage falls 
below 4, the conversion becomes incomplete, as de- 
monstrated by experience. As was to be expected, 
experience showed the necessity of an excess of oxy- 
gen over that which the calculation demands. 
Hence the average composition of the gas mixture, 
in leaving the pyrite burner, is like this : N = 81 ; 
SO 2 = 8.8; = 9.6 in 100 volumes. The plant 
(equal to what in laboratory speech we call appa- 
ratus) for the manufacture of sulfuric acid comprises 
the following principal parts: 1, the burners; 2, 
the Glover tower; 3, the lead chamber; 4, the Gay- 
Lussac tower ; 5, the concentrating outfit. The diagram, 
Fig. 63, shows the arrangement of the plant in ground 
plan. EBB are three burners or kilns for pyrite ; 
D is the dust chamber, of brickwork for the purifi- 
cation from solid particles of the gas ; G is the Glover 
tower ; MC is the mixing lead-chamber and C f is 
the main lead-chamber; GL is the Gay-Lussac 
tower with the chimney attachment Ch, from which 
the waste gases escape into the air. In Fig. 64 the 
plant appears in sectional elevation. The pyrite 
burner shows as a rectangular shaft or stack about 
12 feet high and built of fire-brick. Several of them 



MANUFACTURE OF HYDROGEN SULFATE. 221 




Pffi 

CD CO CO 

, I 




222 CHEMISTRY SIMPLIFIED. 

are generally built close together in a row (see ground 
plan). Two opposite doors 1, 1 allow the iron oxyd 
to be drawn out, while a bell and hopper arrange- 
ment, 2, serves to introduce the pyrite, without los- 
ing any gas. At 3 is a strong cast-iron grate in the 
form of a cone ; through the canal 4 air is admitted 
to this grate. Small inlets 5, 5, 5 admit air to the 
upper part, when necessary. The burner is started 
with a wood fire, until the lower furnace walls are 
at red heat. Then small charges of pyrite are intro- 
duced until the stack is full to within 6 feet of the 
top. The burning of the sulfur into SO 2 furnishes all 
of the heat needed from this period on. A 1-foot iron 
pipe takes the gases from each burner into the dust 
chamber D which is built of common brick ; two 
vertical partitions 7, 8 divide the chamber into three 
sections and force the gases to a broken up and down 
course shown by the arrows. Doors 9, 9 permit the 
removal of the ore-dust from time to time. A two 
foot iron pipe, 10, takes the gases to the Glover tower 
G so named after its inventor. It forms a brick 
stack of square section ; the inside is lined with hard 
glazed bricks which resist the action of the acids. 
A perforated arch of such bricks, 11, serves to sup- 
port a structure of loose, hard, stoneware bricks and 
cylinders 12. The idea is to present a very large 
surface over which the acid which comes from tank 
T above the tower, can spread and come in contact 
with the hot gases. 

Purpose and function of the Glover tower. (1) To 
cool down the gases to the temperature needed in 



MANUFACTURE OF HYDROGEN SULFATE. 223 

the chambers. (2) To utilize the nitrose from the 
Gay-Lussac tower. The term " nitrose " was intro- 
duced to designate the combination H 2 S0 4 .NO. 
The nitrose is pumped from the tank, T, under the 
Gay-Lussac tower, by means of air pressure through 
lead pipes into the one-half of the tank, T, on top of 
the Glover, and the dilute acid formed in the cham- 
ber, MCj is pumped through pipe line, 13, into the 
other half of T. From these tanks properly regu- 
lated streams pass through air-tight openings of the 
top of the tower upon the cylinder which forms the 
apex of the stoneware pyramid. Here the concen- 
trated nitrose in mixing with the dilute chamber 
acid sets free the NO, while the now semi-concen- 
trated acid in running over the large brick surface 
comes to boiling in contact with the hot burner 
gases, splits into concentrated acid, which collects 
below the arch, and is drawn thence by automatic 
syphon in the tank, T, under the tower, whence it 
is pumped to the top of the Gay-Lussac tower to 
begin a new circuit of absorbing NO, etc., ad infini- 
tum. Aqueous vapor from the boiling acid in the 
meantime has mingled with the liberated NO, and 
with the other gases passes through pipe, lh into the 
mixing chamber, MC. Here the action sets in : 

SO 2 + + NO + H 2 = H 2 (S0 4 ) + NO. 

The H 2 S0 4 + water vapor forms a dense white fog, 
which becomes liquid when it strikes a cool surface ; 
thus the principal precipitation occurs along the 
sides of the chamber, whence the acid runs down 



224 CHEMISTRY SIMPLIFIED. 

into the leaden pan, 15. Owing to the misty, foggy 
condition of the acid such an immense size of the 
chambers is required. From an average of fifteen 
English works, the chamber space is 21 cubic feet for 
one pound of sulfur burned in 24 hours. A plant, 
therefore, which is to produce five tons of 66 Be', 
acid in 24 hours will require a chamber space 

V = 10000 X 0.94 X 21 X ft = 64457 cubic feet. 
Making the chamber's cross section 20' wide by 
16' high we get an area of 320 square feet, and 
hence f|{p- = 201.4 feet. Such a length would be 
best broken into 3 chambers ; to wit : A mixing 
chamber 50 feet long, a main chamber 101.4 feet 
long, an end chamber 50 feet long. The cost of 
the lead for these three chambers will be arrived at 
thus : 

2 sides (201.4 X 16 each) = 6445 square feet. 

1 top 201.4 X 20 = 4028 square feet. 

1 bottom 201.4 X 22 - 4430 square feet. 

6 ends (20 X 16 each) = 1920 square feet. 

For Gay-Lussac tower and 

connection pipes = 2000 square feet. 



Total 18823 square feet. 

Sheet-lead is rolled of many thicknesses, which are 
counted as so many pounds per square foot, hence 
1 lb., 2 Ibs., 3 Ibs., ... 12 Ibs. sheet lead. Six 
Ibs. per square foot is thick enough for the cham- 
bers, hence the total weight of lead will be 18823 X 
6 = 112938 pounds, and at 6 cents per lb., this 
represents a cost of $6,776.28. 



MANUFACTURE OF HYDROGEN SULFATE. 225 



The GayLussac tower and its functions. The pur- 
pose is to expose a maximum of surface covered 
with a moving film of concentrated H 2 SO 4 to the 
ascending gas mixture from the last chamber. 
When thus exposed the H 2 S0 4 will absorb NO. 
The absorption is proportional to the concentration 



FIG. 65. 



FIG. 66. 





of the acid. Much aqueous vapor is in the gas 
mixture, which will be absorbed, and hence dilute 
the acid, lowering its capacity for NO. Thus comes 
the more recent practice of setting- up two towers, 
one for drying the gases, the second for the absorp- 
tion proper. A, Fig. 65, is a vertical section of the 
tower as commonly in use. Over a perforated arch 
15 



226 



CHEMISTRY SIMPLIFIED. 



1 there lies a column of coke-pieces of fist size. 
From a shallow tray #, studded with many small 
dripping tubes falls the concentrated acid over the 
coke, soaks into the latter and finally comes out as 
nitrose through the arch 1 into a tank T" under 
the tower. The gases enter I and leave at II into 
the chimney Ch. A pipe 8 passes through the 
leaden top (tightly) and feeds the acid from the 
tank T into the tray 2. 

A more perfect arrangement is shown in Fig. 
66, known as the Lunge-Rohrmann plate column. 
The tower is of sheet-lead in wooden or iron frame. 
Supporting ledges 4, 4 are provided, fused on (burned 
on in technical speech) along the walls or sides. 

FIG. 67. 




Similarly a central support 5 is provided of glazed 
stoneware. In the cross section Fig. 67, we see that 
there are four plates, each one perforated by 16 
holes, and each hole enclosed within a small square 
area acting as a shallow reservoir. It is claimed 
for this system that it is quite superior in action to 
the coke filling, inasmuch as the surface is very 
large and yet regular, especially when the perfora- 
tions of the alternate plates are not directly above 



MANUFACTURE OF HYDROGEN SULFATE. 227 



one another, but so that the liquid drops from *the 
upper hole upon the dividing ridge of the lower 
panel. 

Concentration of the chamber acid. Experience 
demands that enough water be delivered to the 
chamber, as steam or as spray, so f that the con- 
densing acid corresponds about to the tri-hydrate 
H 2 (SO 4 ).3H 2 0. This liquid's specific gravity is 
50 B. corresponding to 64 per cent. H 2 S0 4 . For 
many purposes such a strength is sufficient, for others 
it must be made as strong as possible. Between the 



FIG. 68. 



FIG. 69. 





two extremes lies the strength of 60 Be\ = 80 per 
cent. H 2 (SO) 4 . This grade is known in the trade 
as pan acid, because it is obtained by heating the 
chamber acid in leaden pans. At a higher concen- 
tration than 60 per cent., the hot acid begins to at- 



228 CHEMISTRY SIMPLIFIED. 

tack the lead of the pan, making white lead sulfate 
and SO 2 . The further concentration must be carried 
on in retorts of either glass or platinum. Large 
glass retorts break easily ; those of platinum are 
very costly. Hence a combination of the two is 
sometimes used in which the bottom is of platinum, 
the top or helmet of glass, or the helmet of lead. 
Figs. 68 and 69 illustrate the Gridley system of con- 
centrating in glass retorts by continuous process. 
Fig. 68 shows one retort R in elevation, while Fig., 
69 is a ground plan showing the combination of 4 
retorts into a self-acting system. We see the retort set 
into an iron basin with a layer of coarse sand between 
iron and glass. Heat is applied to each retort sepa- 
rately \yy a Bunsen burner of sufficient size. Each 
retort has an inlet for the weak acid 1 and a syphon 
outlet 2 (see ground plan specially). The helmet H 
carries the weak-acid distillate into the pipe P of 
sheet-lead. As each retort of a set stands higher 
than its oneside neighbor and lower than the other 
neighbor, the acid of steadily increasing strength 
flows from R l to R and from R 4 into the cooling 
worm W, which lies in a stream of running water ; 
from the worm the acid of 65.5 Be', flows into the 
carboy K. By general agreement this is the cheapest 
way of concentrating sulmric acid. But only acid 
of 92 to 93 per cent, can be made by it. 

In Figs. 70 and 71 we see an all-platinum still of 
the most modern construction, for making acid of 
98 to 99 per cent. H 2 S0 4 , as furnished by the firm 
of Lemaire and Co. of Paris. The strenuous effort 



MANUFACTURE OF HYDROGEN SULFATE. 229 

necessary is divided between two stills A, B, each 
upon a separate fire-place F y F'. Each still is a flat, 
elliptical vessel, Fig. 71, ground plan. The still is 
in three detachable pieces, 1 the pan, # the lid, 3 the 
helmet and snout to carry off the vapors. (Snout 
not shown.) The older forms of still are circular. 
The elongated form is chosen because it gives a 
more economical use of the heat. The pan 1 is dif- 
ferent in the two stills. In A the pan has 4 longi- 



FIG. 70. 



FIG. 71. 




tudinal compartments, it consisting in fact of 2 con- 
centric pans, the inner about { inch deeper than the 
outer. Thus a larger surface of evaporation is 
gained. Now supposing the acid of 56 Be. being 
fed into A at the point /, it will flow along the 
outer compartment as the arrows point. The cur- 
rent will pass through an opening in the partition 
at a into the inner compartment and circulate to b, 
whence the syphon tube S, S, S will draw it into the 
still B at G. The partitions in B are transverse and 
do not touch the bottom, but leave f inch opening. 
This is necessary for cleansing the pan as from the 



230 CHEMISTRY SIMPLIFIED. 

highest concentrated acid a small percentage of 
iron sulfate precipitates. But here too a meander- 
ing of the current is brought about as the arrows 
indicate. At d another syphon tube takes the con- 
centrated acid to the cooler C whence it goes either 
to the carboys or iron tanks, because at ordinary 
temperatures the strongest H 2 S0 4 does not act upon 
iron. It is found that by the best care the platinum 
will dissolve in the strong acid at about the rate of 
1 gram per ton of acid. For five tons daily produc- 
tion the bottom pan of the still will therefore lose 
300 X 5 = 1500 grams a year and can at best last 2 
years. 

MANUFACTURE OF OIL OF VITRIOL AND SULPHURIC 
ACID BY THE CONTACT PRINCIPLE 

1. Oil of vitriol and SO B by Winkler's method. 
Fundamental facts represented by the following 
equations : 

(a) H 2 S0 4 (93 per cent, acid) -f contact surface 
at yellow heat = H 2 + SO 2 + + aq. 

(b) H 2 + SO 2 .+ + aq. + cold contact sur- 
face == Water + (SO 2 -f 0), (moist gases). 

(c) SO 2 + + moisture -+- spray of concen- 
trated acid = SO 2 + + less cone. H 2 S0 4 (dry 



(d) SO 2 -f (dry) + platinated asbestus (at dull 
red heat) == SO 8 (as white vapor). 

(e) Spray of H 2 S0 4 (93 per cent, acid.) + nSO 3 
= H 2 S0 4 + nSO 3 =; oil of vitriol, 



MANUFACTURE OF HYDROGEN SULFATE. 231 

In words : 93 per cent, acid is broken up into 
H 2 + SO 2 -f by being spread over a highly 
heated surface of acid-resisting material. The re- 
sulting mixture of water vapor, sulfur dioxyd and 
oxygen is passed through cooling tubes in which 
most of the water vapor becomes liquid water. The 
gases are then sent over an extended surface of 93 
per cent, acid (a fine spray) by which the water- 
vapor becomes fully absorbed, and lastly the mix- 
ture of dry SO 2 -f- is passed through a cylinder 
heated up to dull red heat, and filled with 
asbestus over which a film of platinum has been 
spread. Here then the platinum is the carrier for 
the oxygen, or the transfer agent, as in the ordinary 
process the NO is the transfer agent. 

Finally the SO 3 can either be condensed in glass 
vessels as solid, silky, trioxyd, or it can be sent 
against a fine spray of 93 per cent, acid, in which 
the SO 3 dissolves. By increasing or decreasing the 
volume of the spray one will be able to get oil of 
vitriol (fuming sulfuric acid) of any degree of 
strength. Simple as the process appears, there are 
considerable technical difficulties, notably the diffi- 
culty of keeping the apparatus from rapid deteriora- 
tion. 

2. Making sulfuric acid by contact directly from the 
pyrite. The principle which underlies this plan is 
the same as in the preceeding. Why can we not 
make H 2 S0 4 by passing the mixture of gases com- 
ing from the pyrite burner, namely nitrogen, sulfur 
dioxyd, and oxygen, directly over platinated a$r 



232 CHEMISTRY SIMPLIFIED. 

bestus? The question has been asked. At first 
sight there seems to be no valid objection and the ex- 
periment proves the feasibility. The cost should 
certainly be less, no lead chambers, no expensive 
stills required for the concentration. Works have 
been built on this plan and run for a number of 
years. It seems however that the conversion of SO 2 
into SO 3 is incomplete owing to the presence of the 
large volume of nitrogen. Likewise the condensa- 
tion of the SO 3 in this diluted condition is very diffi- 
cult and gives much weak acid, which has to be con- 
centrated after all. Thus the chamber method is 
not likely to become superseded for some time, or 
until the present difficulties of the contact method 
have been finally overcome by ingenuity and ex- 
perience. 



CHAPTER XIV. 
OTHER COMPOUNDS OF SULFUR. 

We may say that sulfur posesses a strong leaning 
or affinity towards combination with the metals 
nearly equal in this respect to oxygen and chlorine. 
The product of the union we call sulfid. 

CuS CuO CuCl 2 

Copper Sulfid Copper Oxyd Copper Chlorid. 
Oxyds and sulfids are mostly insoluble in water ; 
chlorids are mostly soluble in water. It follows that 
the so-called metallic ores are either sulfids or oxyds. 
Thus the iron ores are oxyds and sulfids : Fe 2 3 , 
Fe 3 4 ; and FeS 2 . The copper ores are Cu 2 S, CuS, 
CuFeS 2 , Cu 2 0, CuO (exceptionally native copper, 
Cu). The lead ore is PbS, zinc ores are ZnS and 
ZnO. Tin ores are CuSnS 2 and SnO 2 . The only 
exception among the common metals is aluminum ; 
of it only the oxyd A1 2 3 is known but no com- 
bination with sulfur, except in the form of a sulfate, 
A1 2 (S0 4 ) 3 . This means that aluminum has no af- 
finity for sulfur at ordinary temperature and in 
water solutions. In a general way w r e conclude that 
nature utilizes the affinity between sulfur and the 
metals to concentrate the latter within the rocks and 
thus make it possible for man to mine and extract 
them at a profit. Example : Rub together with 
(J233) 



234 



CHEMISTRY SIMPLIFIED, 



mortar and pestle, 1, a drop of mercury and sulfur ; 
2, finely divided metallic copper and sulfur. In 
either case a new, black substance is formed, tbe 
sulfids of mercury and copper. Gentle beat in a 
closed vessel converts the black sulfid of mercury 
into a dark-red sulfid of the same composition and 
when ground fine it is called vermilion. 

The copper sulfid CuS has a blue color ; it cor- 
responds to the natural mineral covellite or indigo 
copper. Kept at a red heat in a glass tube, which 
is closed at one end, it changes into the bright grey 
sulfid Cu 2 S thus : 

2CuS + red heat = Cu 2 S + S 

one-half of the sulfur subliming into the cooler part 
of the tube. 

Hydrogen sulfid (old name sulphuretted hydrogen). 

FIG. 72. 




In acting with dilute H 2 S0 4 or dilute HO upon 
iron sulfid or zinc sulfid a very peculiar odor ap- 
pears, due to a rapidly generating gas. Let A, Fig. 
72, be a flask holding about 250 c.c., fitted with 
stopper funnel tube and evolution tube. Bring into 
it 20 grams of iron sulfid (FeS) anil allow the acid 
to fall in drops from the funnel. (5 % H 2 S0 4 must 



OTHER COMPOUNDS OF SULFUR. 



235 



be used). B is the wash tube with water and C is 
a U-tube filled with CaCl 2 in small pea size. The 
gas will issue dry and pure at the narrow opening 
1. If a match be applied the gas will burn with a 
pale blue flame and if a dish D with clean undressed 
face and containing cold water be held into the 
flame, drops of colorless liquid (water) and yellow 
sulfur will be precipitated upon the dish D, whilst 
the pungent odor of SO 2 is given off. Hence the 
gas must be composed of S and H. 

Proof that the compound is H 2 S. Let the gas enter 
the knee-tube, (Fig. 73), over mercury, until the 
latter's level is below the knee ; mark the level with 

FIG. 73. 




sticker, M. Introduce a piece of tin, S, and shove 
it to near the end of the knee-tube. Bring S to red 
heat with lamp. Tin unites with the sulfur, forming 
brown SnS. After cooling we find volume of gas 
unchanged. We reason since 1 volume H n S m con- 
tains 1 volume H, then 
Weight of 1 volume H n S m = 1.521 
Peduct wt. of 1 vol. H - .089 

1.432 == weight of S. 



236 CHEMISTRY SIMPLIFIED. 

But 1.432 is equal to the wt. of \ vol. sulfur, hence 
one vol. H n S m contains 1 vol. of H + J vol. S, or 
2 vols. of H + 1 vol. S the symbol is IPS. 100 
grams of H 2 S contain S = 94.2 ; H = 5,8 grams. 
Now we can write the equation of formation : 

FeS + H 2 S0 4 == FeSO 4 + IPS 
FeS + 2HC1 = Fed 2 + H 2 S. 

Generation of H 2 S in a steady current at the mini- 
mum of cost. This is a very important problem, 
because in all analyses, both qualitative and quan- 
titative, IPS must be used. Different forms of 
apparatus have been described by inventors. Of 
all those the Koenig's apparatus serves the purpose 
best. It has already been described on pp. 61 to 
63, Fig. 28, for the generation of chlorine gas in 
a steady, long-continued current. The apparatus is 
universal, may be used whenever a gas is to be 
produced from a solid by means of a liquid acid. 
Read over the description on pages 61 to 63, with 
the following changes : The generating tube, Gr, is 
to be charged with pieces of iron sulfid, FeS, of 
hazel-nut to pea size, the funnel being removed, up 
to the end of the funnel tube. (For chlorine we 
only fill the tube one-third.) The funnel bulb con- 
tains 5 per cent. IPSO 4 (never any stronger), 27 
c.c. of concentrated H 2 S0 4 in 1000 c.c. of water. 
This dilute acid acts upon FeS at ordinary temper- 
ture, but more energetically at 60 C., to which tem- 
perature the small flame at b heats the water in the 
jacket, J. Regulate the stop-cock at F so that a drop 



OTHER COMPOUNDS OF SULFUR. 237 

of acid will issue per second. The gas will then 
flow from the goose-neck, L, in a strong, even cur- 
rent. The other product, which is a water solution 
of FeSO 4 with a small quantity of free acid, will be 
discharged through the rubber tube, R, into the flask, 
IF. Thus the acid from above will act upon a 
material surface always clean, always under equal 
conditions, and hence produce the same quantity of 
gas per minute. 

Note. The pressure of the gas is equal to a col- 
umn of water of the length of the funnel tube, 
provided that the length of the tube, R, from its 
lowest point in the bend to the discharge at P be 
equal to the length of the funnel tube or greater. 
If you should connect the rubber from the goose- 
neck to a long tube and dip the latter to the bottom 
of a high beaker-glass filled with water, so that the 
length of the water column be greater than the 
length of the funnel tube, then the gas will not go 
through the liquid, as it should do, but it will 
escape through the funnel or at P. The funnel can 
be supplied from a large bottle by means of a syphon 
and a pinch-cock or a glass stop-cock. The funnel 
holds sufficient acid for any ordinary operation in 
analysis. One often neglects to look after things at 
the right time, and so in this case the whole charge 
of iron sulfid might be used up by sheer neglect if 
the acid supply kept on running. 

Properties of H 2 S. Strong, unpleasant odor. 
Colorless. At 11 C. under a pressure of 15 atmos- 
pheres, 15 X 15 = 225 Ibs. per square inch, the gas 



238 CHEMISTRY SIMPLIFIED. 

becomes a mobile, colorless liquid. The latter be- 
comes a white, snow-like mass of crystals at 85 C. 
The gas acts as a poison on man and animals, pro- 
ducing faintness, headache ; if persistently breathed 
it causes death. A horse was placed in a large room 
which had been made thoroughly air-tight. One- 
half per cent, by volume of EPS was mixed with 
the air of the room, then closed. The horse died in 
15 minutes. Always generate the gas under a well- 
drawing hood or in the open air. One volume H 2 S 
weighs 1.180 if the same volume of air weighs 1.000. 
By calculation the specific gravity is 1.1747 when 
air = 1, and 18 for H = 1. One c.c. of air weighs 
0.001293 gram, therefore 1 c.c. IPS will weigh 
0.001293 X 1.180 0.001526 at C. and 760 mm. 
mercury pressure. 

One volume water at 15 C. absorbs nearly three 
volumes EPS. The resulting solution contains 
0.001526 X 3 X 100-0.4578 p. c. of H 2 S by weight, 
about 0.5 per cent., and is named H 2 S water. The 
solution does riot keep. It decomposes rapidly in 
the sunlight, thus EPS + water -f + sunlight = 
S -f- EPO + water. It will keep longer if the water 
has been boiled, then cooled quickly, before passing 
the EPS into it, and if the bottle is then sealed 
air-tight before the oxygen of the air can dissolve 
again in the water. Brown-glass bottles are best, 
because the active sun rays do not penetrate much 
through such glass. EPS water freshly prepared is 
a very handy reagent both in qualitative and 
quantitative work. The EPS water shows slight 



OTHER COMPOUNDS OP SULFUR. 239 

add action on litmus. The gas itself decomposes 
more readily than H 2 0, thus : 

H 2 S in red-hot glass tube = H 2 + S (sulfur de- 
posits). 
IPS H- H 2 S0 4 = H 2 -f S (sulfur floats on the acid). 

H 2 S + electric spark = IP + S (Put 10 c.c. of gas 
into eudiometer over mercury and let* the spark pass 
over ; sulfur deposits as a snowy cloud and 10 c.c. 
of hydrogen are left. This is another proof of its 
composition of 1 vol. H -f- J vol. S.) 

Because concentrated H 2 S0 4 decomposes the gas, 
we reason that one must not use H 2 S0 4 as a dryer, 
but CaCl 2 instead, for this gas. 

ACTION OF H 2 S UPON THE ALKALINE HYDROXYDS. 

The gas is eagerly absorbed by both weak and 
strong solutions of KOH, NaOH, NH 4 OH. 

(a) Action of H 2 S upon K(OH) in water at air 
temperature. 

IPS + K(OH) == K(SH) + H 2 and IPS + 
2K(OH) = K 2 S -|- 2H 2 0. Dissolve about 5 grams 
of KOH in 25 c.c. of water. Divide the liquid into 
2 equal parts in two test-tubes. Let IPS pass into 
one of the tubes until there is no further absorption, 
that is, until the size of the bubbles does not di- 
minish in the ascent through the liquid, and you 
smell the IPS strongly. Then the colorless liquid 
will contain K(SH), potassium sulfohydroxyd. Now 
pour the contents of the other tube into the first and 
you will have 

K(HS) + KHO = K 2 S + IPO. 



240 CHEMISTRY SIMPLIFIED. 

The solution of potassium sulfid is likewise a color- 
less liquid. The properties of the two bodies are 
not quite alike. Both, by gentle evaporation over 
H 2 S0 4 in a dessicator (a glass vessel with a ground 
rim and ground cover or plate of glass), give crys- 
tals, but they do not belong to the same system. 

K(SH) can stand red heat without decomposition 
if made in the following way in a glass retort, no 
water being present : 

K 2 C0 3 + 2H 2 S + red heat = 2K(SH) + CO 2 + 

H 2 0. 

In this respect it acts like the hydroxyd K(OH). 
It is a sulfo base, which can form with sulfo acids, 
sulfo salts. 

(b) Action of H 2 Supon Na(HO). 

H 2 S + Na(OH) + water = Na(SH) + H 2 0. 
IPS + 2Na(OH) + water = Na 2 S + 2H 2 + water. 
They act like the potassium compounds. 

(c) Action ofH^Supon NH 4 (HO). 

H 2 S + NH 4 (HO) = NH 4 (SH) -f IPO. 
H 2 S + 2NH 4 (HO) = (NH 4 ) 2 S + 2H 2 0. 

Both colorless solutions. 

(d) Action of H 2 S upon Ca(HO) 2 . 

Make 2 grams of quicklime into milk of lime 
with 20 c.c. of water and pass H 2 S into solution 
until saturated ; the solution becomes clear in meas- 
ure as the hydroxyd passes into the sulfohydrate, 
thus 

Ca(HO) 2 + 2H 2 S = Ca(SH) 2 + H 2 0. 



OTHER COMPOUNDS OF SULFUR. 241 

The solution of the sulfohydrate decomposes during 
evaporation, into CaS and H 2 S ; the CaS is not solu- 
ble in water. 

Ca(SH) 2 is used by tanners to remove the hair 
from the hides. Even from the living skin the hair 
falls out when the solution is repeatedly applied. 

Calcium monosulfid, CaS, is best prepared in the 
dry way. Mix gypsum with charcoal powder in 
the proportion of gypsum 3.6 parts, charcoal 1 part, 
and heat the mixture in a fireclay crucible to full 
redness in a suitable furnace until the blue flame 
stops burning at the small opening left in the lid of 
the crucible. 
CaS0 4 .2H 2 + 4C + red heat = CaS + 2H 2 + 

4CO. 

The porous mass of CaS is white, when the materials 
are pure. It is mostly somewhat reddish-yellow. 
If exposed to the sunlight during the day it will be 
luminous during the dark of the night. It is a 
phosphorescent body. It is used for faking ghosts. 
When mixed with water it decomposes : 

2CaS + 2H 2 = Ca(SH) 2 + Ca(HO) 2 
The solutions of the alkaline sulfids become yellow 
after some time of standing in contact with the air. 
This phenomenon is due to the forming of poly- 
mlfid thus : 

2K 2 S + H 2 + = 2K(OH) + K 2 S 2 , pot. disulfid. 

2K 2 S 2 -f H 2 + = 2K(OH) + K 2 S 4 

2K 2 S n + IPO + = 2K(OH) -f K 2 S 2n , 

pot. polysulfid. 
16 



242 CHEMISTRY SIMPLIFIED. 

As the action advances the color of the liquid 
deepens until it becomes blood-red ; the capacity of 
the potassium for sulfur is now satisfied, (2n = 9) 
but the oxydation keeps on, the solution deposits 
sulfur in crystals, the color becomes lighter until, 
at last, a cloudy solution remains with the sulfur 
all separated out in crystals ; the liquid is K(OH) 
water thus : 

2K 2 S 9 + H 2 + = K 2 S 8 + 2K(OH) -f 10S. 
Oxydation, therefore, means substitution of in 
the place of 8. Note. Write out these reactions for 
Na 2 S and (NH 4 ) 2 S. 

ACTION OF SULFUR ON THE ALKALINE HYDROXYDS. 

Bring flour of sulfur together with a strong solu- 
tion of KOH (1 : 3) into a test-tube. At ordinary 
temperature the action is too slow to be perceptible. 
On heating, the liquid assumes a yellow color, which 
grows in intensity at the boiling heat, while the 
sulfur disappears. No gas is seen to escape, hence 
the oxygen of the KOH, as well as the hydrogen, 
must enter into the new unions. The brown-red 
liquid acts upon copper or silver like K 2 S + H 2 0, 
that is to say, a black sulfid CuS or Ag 2 S forms, 
while K 2 unites with the H 2 as 2KHO. Hence 
we may assume that the first action of 2KHO upon 
S gives K 2 S + H 2 2 . But the latter H 2 2 is 
hydrogen peroxyd, a powerful oxydizing agent, 
which tends to transfer one to any oxydizable 
body in its neighborhood, and this is S. Now we 
know two oxyds of sulfur, SO 2 and SO 3 , either of 



OTHER COMPOUNDS OP SULFUR. 243 

which might form, but in fact quite another com- 
bination results, namely, S 2 2 , and this oxyd com- 
bines thus with 2KHO to form K 2 (S 2 3 ). Evi- 
dently one can explain this in another way by 
assuming first the forming of SO 2 , then of K 2 (SO 3 ), 
and then the entering of one S into tljis molecule in 
presence of an excess of KHO and of S molecules. 
The final reaction presents itself in the balanced 
equation : 

mKHO + nS + water + heat=2K 2 S 9 +K*(S 2 3 )-f- 
3H 2 + water -f (m 6)KHO -h (n 20)S. 

K 2 S 9 is potassium polysulfid (the maximum of 
saturation), K 2 (S 2 3 ) is potassium thiosulfate or 
potassium hyposulfite. 

If XaHO be taken instead of KHO the action 
will be 

6XaHO -f 20S = 2Xa 2 S 9 + Na 2 (S 2 3 ) + 3H 2 

Xa 2 (S 2 3 )-flOH 2 easily crystallizes in large, trans- 
parent, colorless crystals. It is the so-called hypo 
of the photographers because its water solution dis- 
solves the insoluble AgBr of the negative plate, but 
not the metallic silver which resulted from the ac- 
tion of the developing agent upon the exposed plate, 
and therefore fixes the image. Na 2 S 2 3 also dis- 
solves the insoluble Pb(S0 4 ). It is the chief in- 
gredient of the extracting solution in the Russell 
process for extracting the silver from its ores ; hence 
a most important substance. 

Technical manufacture of the salt. Boil together 
NaHO, S and water until the sulfur is all dissolved. 



244 CHEMISTRY SIMPLIFIED. 

Then pass SO 2 gas into the liquid until the yellow 
color has disappeared and allow the hot liquid to 
cool. The hyposulfite crystallizes. The proportions 
are : Solid NaHO 96 parts, flowers of sulfur 64 parts, 
water 500 parts. The principle of the action is that 
SO 2 takes from the polysulfid one S, turning into 
S 2 2 , and the latter decomposes 2NaHO to form 
Na 2 S 2 3 +H 2 0. Thus: 

Na 2 S 9 + ISNaOH + 9S0 2 =9Na 2 S 2 3 +9H 2 0+ 
Na 2 S, H 2 0+Na 2 S + S0 2 =Na 2 (S0 3 )-f-H 2 S; 2H 2 S 
+S0 2 =S 3 -f2H 2 0. 

Ultimately there must be a precipitation of sulfur 
if an excess of SO 2 is run into the solution. 

Second process. The raw material is here the 
waste product from the Leblanc soda process, which 
is essentially a mixture of CaS+CaO. If this waste 
be exposed to the action of air for a proper period an 
oxydation will set in, by which calcium thiosulfate, 
calcium sulfate and sulfur are produced. If this 
oxydized material be extracted with water the solu- 
tion contains chiefly, Ca(S 2 3 ), calcium thiosulfate. 
On the addition of Na 2 C0 3 we obtain a precipitate 
of CaCO 3 and a liquid holding Na a (S 2 O 8 ). Evapo- 
ration and crystallization furnish commercial hypo. 

Note. The oxyd SO or S 2 2 has not yet been 
obtained in the free state. For as soon as an acid 
is added to a solution of hypo there is an action 
thus : Na 2 (S 2 3 )+water + 2HCl=2NaCl+S0 2 +S. 
This precipitation of sulfur, upon acidification, is 
an excellent means for recognizing the presence of 
a thiosulfate. 



OTHER COMPOUNDS OF SULFUR. 245 

ACTION OF H 2 S UPON THE SOLUTIONS OF METALLIC 
SALTS. 

(1) Upon solutions of potassium, sodium, ammonium 
and calcium salts. We find that no action takes 
place. 

K 2 S0 4 4- water + H 2 S = K 2 S0 4 -f water + H 2 S 
Na 2 S0 4 -f water -f H 2 S = Xa 2 S0 4 + water -f H 2 S 
(NH 4 ) 2 S0 4 +water + H 2 S = (NH 4 ) 2 S0 4 -{- water + 

H 2 S 

CaSO 4 + water + IPS = CaSO 4 + water + H 2 S. 
Reasons : If there were action it would have to be 
thus 
,K 2 S0 4 + water + H 2 S = K 2 S + H 2 S0 4 + water. 

But we have seen that: K 2 S + water + H 2 S0 4 = 
K 2 S0 4 -f water + H 2 S, and similarly for other sul- 
fids ; therefore the end equaling the beginning, there 
can be no action. 

(#) Upon solutions of iron-zinc-aluminum salts. 
FeSO 4 + water + IPS = FeSO 4 + water + IPS 
FeCl 2 -f water + IPS = Fed 2 + water + H 2 S 

A1 2 (S0 4 ) 3 + water + IPS = A1 2 (S0 4 ) 3 + water + 

H 2 S. 

There is no action for the same reason as given above. 
We generate IPS by acting upon FeS with very 
dilute IPSO 4 , hence IPS cannot form FeS in pre- 
sence of free acid, which must be formed simul- 
taneously with the FeS : 
FeSO 4 + water -f IPS = FeS + water + H 2 SO*. 



246 CHEMISTRY SIMPLIFIED. 

The same is to be said of zinc. But aluminum does 
not combine with the sulfur in H 2 S under any 
circumstance, in water solution. 

(3) Action of water solution of K 2 S, Na 2 S, (NH 4 ) 2 S 
upon the solutions of iron, zinc and aluminum salts. 

There is always a precipitate formed, but this is 
not the same thing for all the three metals ; thus : 

FeSO 4 + water + K 2 S = FeS + K 2 S0 4 + water 
FeS forms as a voluminous black precipitate. Why ? 
Because there is no H 2 S0 4 formed, but K 2 S0 4 , and 
K is the most positive of the metals, most difficult 
to be displaced in its salts. 

Na 2 S,(NH 4 ) 2 S act the same. Write the equa- 
tions. 

ZnSO 4 + K 2 S + water = ZnS + K 2 S0 4 + water 
ZnS is a white flocculent precipitate. Reason as 
before. 

Write equations for ZnSO 4 + Na 2 S, (NH 4 ) 2 S. 
A1 2 (S0 4 ) 3 + 3K 2 S.+ water = 2A1(OH) 3 + 

3K 2 S0 4 + 3H2S 

as there is no affinity between Al and S, the latter 
must form IPS. Aluminum hydroxyd forms in- 
stead of the sulfid. 

(4) Action of H 2 S upon the solutions of lead, cop- 
per, tin, mercury, silver and gold salts. Here we find 
that precipitation of the sulfids occurs whether the 
solutions be neutral or whether they contain free 
acid. 

PbS, a flocculent, brownish-black precipitate from 
cold solutions, a bluish-grey from a hot solution. 



OTHER COMPOUNDS OF SULFUR. 247 

CuS, a flocculent brownish-black precipitate. 

SnS, a flocculent brown precipitate from stannous 
salts. 

SnS 2 , a flocculent yellow precipitate from stannic 
salts. 

Ag 2 S, a flocculent black precipitate. 

Hg 2 S, a flocculent brown-black precipitate. 

Au 2 S 3 , a fine, granular, brown precipitate. 
SAuCl* + 3H 2 S + 12H 2 + heat = 8Au + 24HC1 
+ 3H 2 S0 4 . 

This means that the gold sulfid has very slight 
stability, heat causing the metal to precipitate. The 
marked difference in the action of the metal solutions 
towards IPS will suggest at once the utilization for 
separating a mixture of salts by means of IPS. 
Let a solution be made up containing the following 
chlorids: SnCl 4 , CuCl 2 , HgCl 2 , A1C1 3 , Fed 2 , ZnCl 2 , 
CaCl 2 , NaCl and KC1. Let HC1 be added and then 
IPS passed through it, the liquid being warm, but 
not boiling. A precipitate falls, being a mixture of 
SnS 2 , CuS, HgS. When the liquid smells strongly 
of IPS filter and call the precipitate of mixed sul- 
fids (A). The filtrate is then made alkaline with 
XH 4 OH, and another precipitate falls, of what? 
Of Al(OH)*, FeS, ZnS. Why? Because the fil- 
trate contains IPS in solution which becomes 
(NH 4 ) 2 S when NH 4 HO is added, and the (NH 4 ) 2 
acts upon the Al, Fe, Zn salts as soon as the free 
HOI is neutralized by (NH 4 )HO. Pass IPS into 
the liquid in order to make a complete precipitation, 
until liquid smells strongly of ammonium sulfid. 



248 CHEMISTRY SIMPLIFIED. 

Filter and call this precipitate (B). Into the fil- 
trate pass CO 2 gas. Why ? Because we know that 
calcium carbonate is insoluble in water, and this 
solution being alkaline with ammonia, the CO 2 will 
form (NH 4 ) 2 C0 3 and this will give with CaCl 2 , 
CaCO 3 plus (NH 4 )C1. Filter. Name this precipi- 
tate (C). In filtrate can now be only KC1 + NaCl 
+ NH 4 C1 + (NH 4 ) 2 C0 3 + (NH 4 ) 2 S. Evaporate 
to dryness in porcelain dish, then heat over direct 
flame until the ammonium salts have smoked away. 
Dissolve the residue (KC1, NaCl) in 1 or 2 c.c. of 
water. We have not come across an action by 
which we can well separate the 2 alkali metals from 
one another except the difference in the solubility 
of the sulfates and the nitrates. Convert KC1 + 
NaCl into K 2 S0 4 + Na 2 S0 4 . How? By adding 
a few drops of H 2 S0 4 to the 1 or 2 c.c. of liquid ; 
by evaporating this liquid to dryness and by then 
heating to red heat until no odor of H 2 S0 4 comes 
off. Because we know by experience the following 
actions: 

2NaCl + H 2 S0 4 + heat = Na 2 SO 4 + 3HC1. 
2KC1 + H 2 S0 4 + heat = K 2 S0 4 + 2HC1. 
Dissolve the residue in little boiling water ; bring 
a drop upon a piece of glass, let evaporate and ex- 
amine under the microscope. As the K 2 S0 4 isvery 
much less soluble than the Na 2 S0 4 , the former will 
crystallize first from the margin of the drops inward. 
In the center will be found the long prismatic crys- 
tals of Na 2 S0 4 , outside the stumpy, almost cubic 
crystals of K 2 S0 4 . 



OTHER COMPOUNDS OF SULPHUR. 249 

If the nitrate test is to be made the first steps 
must be the conversion of KC1, XaCl into KXO 3 , 
XaXO 3 . We remember that AgCl is insoluble in 
water and dilute acids, also that metallic silver dis- 
solves in HXO 3 of medium concentration forming 
AgNO 3 . If therefore we add the AgNO 3 solution 
to the KC1, XaCl solutions so long'' as the white 
cloud is forming, while stirring, then a change will 
occur thus, 

KC1 + AgNO 3 + water = AgCl -f KNO 8 . 
Filtering off AgCl, a drop of the filtrate evaporated 
upon a glass slide will give the characteristic crys- 
tals of the two niters if both metals (K, Xa) are pres- 
ent in the unknown substance, or the crystals of 
either alone, as the case may be. Since K salts im- 
part to the mantle of the gas flame a purple color, 
and Xa salts an orange-yellow color, properly ap- 
plied flame test may decide the question of the pres- 
ence or absence of either of the two metals, but it is 
not here the place to treat of these phenomena in 
greater detail. 

Let us now turn our attention to the precipitate 
(A), and see how far our knowledge will enable us 
to separate and recognize the metals which it does, 
or may contain. 

(a) HgS. All salts of mercury are volatile either 
as a whole, or at least the metal itself. If the mix- 
ture of sulfids includes HgS, we must get a subli- 
mate of some kind by heating this mixture in a 
hard-glass tube, closed at one end. Three inches 
of the tube will suffice. (Precipitate must be dried 



250 CHEMISTRY SIMPLIFIED. 

before placing it in the tube). Heat closed end to 
full'redness : The sulfids melt, HgS sublimes. When 
tube has cooled, break off the closed end, crush glass 
and sulfids, act upon with HNO 3 , pick out the 
glass and evaporate to dry ness, then add water. 

(b) If copper is present, a blue solution results, if 
tin, a white, pulverulent body of SnO 2 ; if lead, a 
white powder of PbSO 4 . (Why ? Because 3PbS+ 
8HN0 3 == 3PbS0 4 + 4H 2 + 8NO.) 

Filter and wash the filter with water. Squirt the 
white powder into a small beaker-glass and add a 
few grams of Na 2 (S 2 3 ) sodium thiosulfate. (Hunt 
up this body under the action of S upon KOH, 
NaOH and study its formation.) Stir well 5 to 10 
minutes, filter. Na 2 S 2 3 acts upon PbSO 4 thus : 

PbSO 4 + 2Na 2 S 2 3 + water = Pb(S 2 3 ).Na 2 S 2 3 

+ Na 2 S0 4 . 

Lead-sodium thiosulphate is soluble in water, hence 
if you filter, the filtrate will contain the lead salt, 
and if a white residue be left on the filter it must be 
SnO 2 . Boil the filtrate and blue-grey PbS falls 
out : 

PbS 2 3 .Na 2 S 2 + H 2 -f heat = PbS + 
Na 2 S0 4 -f H 2 + SO 2 + S. 

(c) Mix the filter ashes with the problematic SnO 2 
together with a little Na 2 C0 3 . Press mixture into a 
cavity on a piece of charcoal, apply a good reducing 
flame with a blow-pipe ; break out the fused mass 
with a knife-point, grind up in a small mortar with 
water. If white flakes with metallic lustre show 



OTHER COMPOUNDS OF SULPHUR. 251 

themselves after washing away the charcoal, then 
the white powder was surely tin. We have thus 
proved the metals in precipitate (A) with no other 
means but such as our progressively acquired 
knowledge has furnished us. 

Precipitate (B). We have present, presumably, 
FeS, ZnS, Al(OH) 3 . It was found tliat all three 
dissolve in HC1 : 

FeS + 2HC1 == Fed 2 + H 2 S. 

ZnS + 2HC1 = ZnCl 2 + IPS. 

Al(OH) 3 -f 3HC1 = A1C1 3 + 3H 2 0. 

By boiling solution with 1 c.c. HXO 3 , we shall 
convert FeCl 2 into Fed 3 , thus: 

3FeCl 2 + 3HC1 + HNO 3 = 3FeCl 3 + 2H 2 + 
NO, the solution turns yellow. NH 4 (HO) decom- 
poses Fed 3 , A1C1 3 , thus: 

Fed 3 + 3NH 4 (HO) == Fe(HO) 3 -f 3NH 4 C1. 

A1C1 3 -f 3NH*(HO) == Al(HO) 3 -f- 3NH 4 C1. 

Fe(HO) 3 , a flocculent, brmvn substance, insoluble 
in water and NH 4 HO. But ZnCl 2 behaves differ- 
ently towards NH 4 HO ; it gives first a white floccu- 
lent precipitate, but on adding more XH 4 HO the 
precipitate dissolves. 

ZnCl 2 + 2NH 4 HO = Zn(HO) 2 + 2NH 4 C1. 

Zn(HO) 2 -f 2NH 4 HO = Zn(NH 4 0) 2 + 2H 2 O, 
soluble in water and XH 4 (HO). Hence it follows 
that we can separate Zn from Fe + Al by means of 
NH 4 HO. Add NH 4 HO to the hot liquid and stir 
until it smells strongly of NH 4 HO ; then, filter. 



252 CHEMISTRY SIMPLIFIED. 

Into filtrate pass IPS and white ZnS falls. Why? 
Make answer yourself from what was given above. 
The forming of a white precipitate proves the 
presence of zinc. Wash the precipitate from NH 4 HO 
from filter into a beaker glass or porcelain dish, 
add Na(HO), a couple of grains, and boil. Fe(HO) 3 
is insoluble in Na(HO) ; Al(HO) 3 is soluble in 
Na(HO), because it combines with the latter to make 
soluble sodium aluminate. 

Al(HO) 3 + 3Na(HO) = AlNa 3 3 -f 3H 2 
Filter. To prove Al in the filtrate, acidify with 
HC1 and then add NH 4 HO. If a white, flocculent 
precipitate falls, aluminum is present. Thus : 

Al(NaO) 3 -f- 3HC1 = A1C1 3 + 3NaCl both soluble. 
A1C1 3 -f 3NH 4 HO = Al(HO) 3 (insoluble)+3NH 4 CL 
To prove that the brown substance is iron hydroxyd, 
dry it on a filter. Put some of the dry mass in a 
cavity on charcoal and heat in a reducing (yellow) 
flame with blowpipe ; then test the mass with a 
magnet. If the substance clings to magnet the 
presence of iron is proved. Why ? Because by the 
reducing flame the trioxyd Fe 2 3 is changed either 
to metallic iron, or to the tetroxyd Fc z O 4 and both 
are magnetic. Thus : 

Fe 2 3 -f- 3C + red heat = Fe 2 + 3CO 

3Fe 2 3 + C + red heat = 2Fe 3 4 + CO 

Precipitate (C). The white substance thrown 

down. by (NH 4 ) 2 C0 3 can only be CaCO 3 according 

to our present state of knowledge. Later on we will 

learn of several more elements whose carbonates 



OTHER COMPOUNDS OF SULPHUR. 253 

will fall with the calcium. But to prove the sub- 
stance absolutely, ignite it with the soda at yellow 
heat. Then moisten with 1 or 2 drops of water. 
If calcium oxyd, it will slake, i. e. get warm and 
swell up a little. If it does, add a few drops of very 
dilute H 2 S0 4 and heat, it will all dissolve; then 
allow one drop of liquid to evaporate on a glass 
slide, and examine the crystals under a microscope. 
They will be the characteristic needle-shaped or 
arrow-head shaped twins of CaSO 4 . 

Thus our analysis is finished. It was introduced 
at this point to show you that analytical chemistry 
simply means the thinking application of the chem- 
ical knowledge which we gradually accumulate by 
experiment. 

SOME OTHER SULFUR COMPOUNDS. 

Hydrogen persulfid, H 2 S 2 . Whenever you acidify 
a solution of ammonium, sodium, or potassium sul- 
fid and then boil the solution, there will be at first 
only the odor of H 2 S. But in measure as this odor 
becomes less pronounced, there will appear another 
odor, pungent and offensive, somewhat resembling 
the odor of fresh onions. As the eyes begin to 
smart if you peel and cut up an onion, so will the 
eyes become affected if exposed to the fumes arising 
from the above boiling solution. This odor is due 
to H 2 S 2 . This latter body is at ordinary tempera- 
ture a yellow liquid, little soluble in water, and 
therefore separating from water in small oily drops. 
Preparation : Pour yellow Na 2 S or (NH 4 ) 2 S into an 



254 CHEMISTRY SIMPLIFIED. 

excess of dilute HC1 or H 2 S0 4 and let the milky 
liquid stand for some hours. Then pour off the 
liquid and you will find this yellow, evil-smelling 
substance at the bottom. There is no technical use 
for it at present. 

Sulfur and chlorine, SCI. Place flowers of sulfur 
(2 grams) in a small tubulated retort and conduct 
dry chlorine gas into the retort. The chlorine is 
eagerly absorbed, generating heat, which must be 
removed by cold water on the outside. A red liquid 
forms. When the sulfur has all disappeared, close 
the tubulus of the retort and let the neck of the re- 
tort project into a receiver, cooled by hydrant water. 
Then heat the retort. A yellow-red liquid con- 
denses in the receiver and finally sulfur remains in 
the retort. The original liquid was therefore a so- 
lution of sulfur in sulfur chlorid. The latter has 
specific gravity of 1.68. It fumes at the air because 
the air-moisture decomposes it : 

4SC1 + 2H 2 == 4HC1 + 3S + SO 2 . 
The one property which makes this sulfur chlorid 
technically valuable is its solvent power for sulfur. 
100 SCI dissolve 73 S. If soft india rubber is placed 
in this solution of sulfur in SCI, the rubber will ab- 
sorb sulfur and become vulcanized. There are other 
combinations of S -j- Cl and S -f- Cl + 0, but of no 
practical interest. 

Sulfur and carbon, CS 2 . Vapors of sulfur com- 
bine with carbon at a red heat forming a vaporous 
compound CS 2 , carbon disulfid. On a large scale 
the substance is made in vertical retorts of cast-iron 



OTHER COMPOUNDS OF SULPHUR. 255 

lined with fire clay. The retorts are filled with 
small bits of charcoal and stand walled in so that 
they may be brought to red heat. The sulfur is in- 
troduced through an inclined tube at the bottom of 
the retort. The vapors of CS 2 are condensed against 
cold water. CS 2 sinks to bottom of eondenser and 
can be drawn off. The first or raw product is far 
from pure and has a most offensive odor. By redis- 
tillation and shaking with metal chips as lead, cop- 
per or mercury, a colorless liquid is obtained whose 
odor is rather agreeable. In 1840 one pound of 
CS 2 was worth 5.00 ; in 1860 only 5 cents ; to such 
an extent had the process been improved. 

Properties. CS 2 is a very mobile liquid. Sp. G. 
= 1.268. Boils at 46 C. High index of refrac- 
tion. Very inflammable, burns with, bluish-white 
flame. When a current of air blows through the 
liquid CS 2 , soon snowy crystals form on the glass 
(CS 2 .H 2 0); the temperature falls to -18 C.; water 
dropped on the liquid freezes instantly. CS 2 easily 
dissolves animal and vegetable fats and oils, and it 
dissolves sulfur. Upon these facts are based the 
technical applications of carbon disulfid. (1). To 
extract the sulfur from the sulfur earth, where the 
latter is abundant (near active or near extinct vol- 
canoes). (2). To extract the fat from bones (glue 
factories, stock-yard slaughter-houses). (3). To ex- 
tract the oil from the seeds (cotton, flax, rape, 
poppy, olive, nut) more thoroughly than can be 
done by mere pressing of the crushed seeds. (4). 
To remove fat from raw wool ; from woolen cloth 



256 CHEMISTRY SIMPLIFIED. 

after dyeing with certain colors. In all of these 
processes much care must be exercised on account 
of the inflammability and the poisonous effects of the 
carbon disulfid. It produces first headache, drowsi- 
ness, stupefaction ; if inhaled for a long time, death. 



CHAPTER XV. 

CARBON COMPOUNDS ; ORGANIC BODIES. 

WE discovered in the lime gas the oxyd of a 
peculiar element which we named carbon from its 
resemblance and action to charcoal. As element 
we find carbon among minerals in two forms : as 
diamond and as graphite. Diamond is the hardest, 
graphite the softest of all minerals. Both resist all 
agents with energy. A yellow heat is required to 
enable oxygen to combine with adamantine carbon 
as well as with graphite carbon. It was a great 
feat to even suspect that diamond was merely crys- 
tallized carbon. Isaac Newton concluded that dia- 
mond must be a combustible substance, on account 
of its high index of refraction. The Academy 
of Florence in 1694 showed by experiment that 
diamond disappears in the focus of a large lens. 
Lavoisier showed, in 1736, that lime gas results from 
the burning of diamond, and Humphrey Davy, in 
1807, proved it to be pure carbon. No attempt at 
making diamond artificially has been a success, up 
to this time, and it is not known by what way 
Nature arrives at the product. That diamond has 
been found in meteoric iron together with amor- 
phous carbon (Koenig, 1889) indicates a high tem- 
perature as one of the conditions. On the other 
17 ( 257 ) 



258 CHEMISTRY SIMPLIFIED. 

hand the perfect crystals found in flexible sandstone 
in Brazil indicate a low temperature as one of the 
conditions. 

Graphite is of very common occurrence in the 
archean rocks either in mica schist or in white crys- 
talline limestone. Sometimes large bunches to- 
gether, but mostly in isolated scales. Graphite 
forms in pig-iron, also in gas retorts at high heat. 
It burns more readily than diamond, especially in 
oxygen gas. Long boiling with fuming HNO 3 con- 
verts it into a yellow substance which has been 
named graphitic acid. 

The mineral coal cannot correctly be named 
carbon, not even the finest anthracite of Pennsyl- 
vania ; it contains however up to 95 per cent, of 
carbon. The great storage of carbon in the earth 
must be looked for in the limestones ; and in the 
air, though the percentage of carbon dioxyd in the 
atmosphere be but 0.02 per cent. Yet all this im- 
mense quantity of carbon is of very little value to 
mankind. As CO 2 it is equivalent to spent energy, 
to an uncoiled spring. At this point intervenes 
organic life contained in the animated cell filled with 
that most mysterious substance, the protoplasm. 
Under its influence carbon dioxyd is split up into 
carbon and oxygen, a part of the oxygen returns to 
the air, the remainder together with carbon and 
hydrogen serving in building up the body of the 
plants. 



CARBON COMPOUNDS. 259 

THE COMBINATIONS OF CARBON AND OXYGEN. 

We saw that the limestone gas is an oxyd of car- 
bon, and furthermore that this oxyd changes into a 
combustible oxyd by the action of zinc and heat. 
There are then two oxyds of very differing proper- 
ties. Being now in possession of the required knowl- 
edge we will proceed to the properties and composi- 
tion of these oxyds. 

Carbon dioxyd, CO 2 , often erroneously named 
carbonic add. This is our limestone gas as well as 
the gas evolved from all carbonates by the addition 
of HC1 or any other so-called acid. This is a sub- 
stance of fundamental importance, and its proper- 
ties should be memorized by any engineer, because 
what is called perfect or complete combustion means 
nothing but the conversion by burning of carbon 
into CO 2 , and because by this combustion the high- 
est heat-value is obtained from coal or any other 
fuel. 

Physical properties. Carbon dioxyd is a colorless 
gas without odor ; but it gives to water a pleasant, 
prickling taste. Its specific gravity is 1.524, hence 
the gas is found near the floor when it issues into, 
the workings of a tunnel, shaft, or other mine-work- 
ing, or in caves such as the dog-cave, where a dog 
dies rapidly, while a standing man, alongside, 
breathes freely. It spec, heat is 0.22 (water =1), 
1 liter at C. weighs 1.97 grams. The gas can be 
liquefied at the freezing-point of water under a 
pressure of 38.5 atmospheres ; at 31 C. a pressure of 
74 atmospheres is required. If two strong metallic 



260 CHEMISTRY SIMPLIFIED. 

vessels (cylinders) be connected by a flexible 
metallic tube, and if one vessel has been previously 
charged with sodium-hydrogen carbonate and sul- 
furic acid in such a way that the agents only come 
together when the cylinder is tilted, then pure 
CO 2 will be generated, and not being able to escape, 
it will liquefy in the second cylinder under its own 
pressure. The temperature rises to 40 C., so that 
upon screwing a metallic receiver upon the second 
vessel, the liquid CO 2 will distill into the receiver 
and the temperature will drop quickly to about 
-80 C. and solidify into white crystal-flakes like 
snow. (Application as a very intense freezing mix- 
ture.) Liquid CO 2 is colorless and mobile, its 
specific gravity at ordinary temperature being nearly 
that of water. CO 2 is quite soluble in water at 
ordinary temperature, and much more so under 
pressure. The sparkling or boiling cold-springs, as 
well as the artificial soda-water are charged with 
the gas under pressure and release it when the 
pressure is taken off. If air be mixed with 4 vol. 
per cent, of CO 2 it becomes unfit for the proper 
oxygenation of the blood in the lungs. In larger 
proportion it suffocates at once. Note ventilation of 
rooms and mines on this account. The poisonous 
action is negative. 

Chemical properties. Moist litmus paper will turn 
to a reddish-purple in a test-tube which has been 
filled with the gas. We assume (without proof) 
that the water-solution contains a weak acid 
H 2 O.C0 2 = H 2 (C0 3 ). The gas is eagerly absorbed 



CARBON COMPOUNDS. 261 

by NaHO, KHO, Ca(HO) 2 , NH*(HO) and even by 
Na 2 CO 3 which changes into 2NaH(C0 3 ). These 
latter actions we utilize for the identification of the 
gas, for its abstraction from a mixture of gases in 
gas analysis. Because if the white precipitate of 
Ca(C0 8 ) be filtered off and then be acted upon by 
dilute HC1 solution, a colorless and odorless gas will 
be evolved which can only be CO 2 , for SO 2 and 
N 2 O 3 are each pungently odoriferous. 

Composition of CO 2 . If a piece of purest charcoal 
be placed in a knee-tube over mercury (see proof 
of SO 2 ), the tube be partly filled with pure oxygen, 
and the coal heated to redness it will burn with a 
bright light. When the temperature has returned 
to normal the volume of gas is unchanged. Hence 
1 volume CO 2 contains 1 volume 0. 

But 1 volume CO 2 weighs 1.965 grams. 
1 volume weighs 1.429 grams. 



0.536 grains. 

hence 0.536 is the weight of carbon which has en- 
tered into combination. We know that the gas is 
CO 2 for it is completely absorbed by introducing a 
drop of NaHO solution. Unfortunately carbon is 
practically non-volatile at feasible temperatures, 
hence we are ignorant of the weight of one volume 
of this element. But since CO 2 and SO 2 are in 
many ways similar and because we did prove in the 
case of SO 2 that the difference between the weights 
of equal volumes of SO 2 and oxygen is equal to J 
volume of sulfur, therefore we can assume that 0.536 



262 CHEMISTRY SIMPLIFIED. 

equals the weight of J volume of carbon, and hence 
our gas contains in one volume 

1 vol. + i vol. C, and 
2 vols. CO 2 = 2 vols. + 1 vol. C 
a contraction of 3 to 2. 

On the other hand it has been found by burning 
a known weight of diamond, that 1 gram of the 
latter (pure carbon) yields 3.666 grams of CO 2 , 
therefore in it are combined C 1.00 with = 2,660. 
Having previously found that the volume ratio is 
CO 2 we arrive now at the atomic weight of carbon, 

2,666 1 1 

! by the proportion ^^ =- or C = g-gggj = 

12.003. The atomic iveight of carbon is 12. The 
weight of 1 volume carbon vapor is 1,072. The 
molecular weight of CO 2 = 44. 

Carbon monoxyd, CO, sometimes called carbonous 
oxyd. This gas may be generated in numerous ways 
of which the most ordinary is the passing of dry CO 2 
over well ignited charcoal at a red heat. Use the 
apparatus given under lime gas, substituting the 
charcoal for the zinc. Let the resulting gas pass 
through solution of NaHO which will absorb any 
CO 2 that may have escaped decomposition. It will 
be seen that for every bubble of CO 2 passing into 
the charcoal, there will be two bubbles of carbon 
monoxyd coming out. 

1 vol. CO 2 + C = 2 vols. CO. 

This gas always generates when any fuel burns im- 
perfectly, that is when there is a lack of oxygen. 



CARBON COMPOUNDS. 263 

If you observe an anthracite stove fire sometime 
after fresh coal has been added (opening the charg- 
ing door) you will see blue flames bursting out all 
over the coal. This is very characteristic of CO 
that is CO + + heat = CO 2 with blue flame. 
Carbon monoxyd explodes with J volume of oxygen 
or 2 j volumes of air. It can therefore be used in 
gas engines. 

The gas is neutral, has a gravity of 0.967, is only 
liquefiable at 139 C. and a pressure of 35.5 atmos- 
pheres. It freezes at 207 C. It is little soluble in 
water. It is very poisonous in a positive way inas- 
much as it combines with the red corpuscles of the 
blood, changing the color to purplish. As such it is 
the worst enemy to the rescuing parties who enter a 
coal mine after an explosion, since the combustion 
is usually imperfect and the gas has nearly the 
same gravity as air. The charcoal poisoning is due 
to this gas; or, any boiler-room may become deadly 
from it if the draft should stop on reverse ; its pres- 
ence cannot be told by the odor. CO is quite 
eagerly absorbed by solutions of cuprous chlorid 
Cu 2 Cl 2 either in HC1 or in NH 4 .HO. (Use in gas- 
analysis.) 

Proof that composition i$ CO. Bring into a eudio- 
meter over mercury 1 volume of the gas + J vol- 
ume of O and explode. There will be left 1 volume 
of CO 2 , it follows that 1 volume of CO contains the 
same volume of carbon as 1 volume of CO 2 . But 
we saw above that 1 volume of CO 2 contains 1 vol- 
ume of O, hence 1 volume CO contains J volume of 
C + | volume of O. 



264 



CHEMISTRY SIMPLIFIED. 



STRUCTURE OF PLANTS. 

The structural unit of the plant is the cell. The 
natural shape of a plant or animal cell is the 
sphere, A (Fig. 74). When cells crowd each other 
in an aggregate, their shape becomes polyhedral, 
C (Fig. 74). When crowded only in one direction 
the cell is apt to become an elongated bag cotton 
or linen fiber, B (Fig. 74). Each live cell has three 

r FIG. 74. 



B 




essential parts : The cell wall, A2, the nucleus, Al, 
the sap or protoplasm, AS, filling the cell space. 
From 80 to 90 per cent, of the sap is merely water. 
The substance of the cell wall is named cellulose. 
Since the body of the plant is made up of root, stem, 
branches, leaves, the flowers being merely modi- 
fied leaves, and since all these are made up either 



CARBON COMPOUNDS. 265 

of live or dead cells, it follows that a plant, after 
the sap is dried out, is practically nothing but cel- 
lulose, with more or less secondary substances, such 
as starch, coloring matter, resin, which had been 
dissolved in the sap or had exuded from the cells 
into the intercellular space. Wood is impure 
cellulose. The purest form of cellulose is cotton, 
pith, paper pulp. Cellulose enters into so many 
applications, and forms as wood one of the engi- 
neer's sources of fuel, that we must devote some 
time and exertion to its study. 

Let some cotton, or filter paper, be dried at 105 
C. in an air-bath until its weight shall have become 
constant. We need not try whether it will burn ; 
we know it will. But let us contrive to burn it 
completely in such a way that the products of the 
combustion can be collected and weighed. The pro- 
ducts of the burning are flame and ashes. Flame is 
a mixture of gases. These gases we must collect. 
We do this first so that we may study the kinds 
(qualitative) of elements in the gases, and then, 
in a more guarded experiment, the quantities. 

(1). We burn 1 gram in a crucible. A very small 
quantity of ashes remains. The ashes partly soluble 
in a little water, show alkaline reaction, and effer- 
vesce with HC1 (K 2 C0 3 ). This potassium carbon- 
ate was not originally in the sap ; the potassium 
was combined with the carbon acids, which we will 
consider hereafter. Combustion converts these salts 
into the carbonate. 

(2). We burn 1 gram in an open tube and draw 



266 CHEMISTRY SIMPLIFIED. 

(by means of an aspirator) the gases through water. 
The latter does not acquire acid reaction, hence 
sulfur and chlorine are not contained in the cellu- 
lose. While the substance burns we note the de- 
posit of water in the cool end of the tube, therefore 
the cellulose contains hydrogen. We draw a part of 
the burning gases through a tube filled with lime 
water and note a strong white turbidity appearing 
showing the presence of carbon in the cellulose. 

(3). We mix a gram of the substance with soda- 
lime (CaC0 3 -f 2Na(HO)) and heat in a tube closed at 
one end no smell si ammonia is noticed. Moist, red 
litmus held into the open end does not turn blue, 
hence nitrogen is absent, and thus we have proved 
that cellulose consists merely of C m , H n , O. 

And now we proceed to find the numerical values 
of m, n and p. By experiment we know that when 
hydrogen passes over CuO at red heat H 2 will be 
formed and metallic copper. Similarly CuO heated 
with charcoal will give metallic copper -f- CO. 
And if CO be passed at red heat over CuO it will 
give Cu + CO 2 . Upon these facts we can now con- 
trive a process and suitable apparatus for the pur- 
pose in hand. 

In Fig. 75 the hard, infusible glass tube T, 20 
inches long, f inch wide, is furnished with per- 
forated stoppers, and is placed into the sheet-iron 
charcoal furnace F, being supported the entire length 
by a half cylinder of iron, thus preventing sagging 
and deformation. The tube is charged at 1 with 3 
inches of coarse copper oxyd, then comes 10 inches 



CARBON COMPOUNDS. 267 

of copper oxyd with which has been intimately 
mixed the cellulose (0.5 gram cut up with scis- 
sors). Then comes at 3 t 5 to 6 inches of coiled 
copper gauze, which has been partly converted 
into CuO by heat and oxygen. Everything must 

FIG. 75. 




be thoroughly dried before charging, as we de- 
sire to catch and weigh the water formed by the 
combustion. Into the stopper 5 fits the bulb-tube 
C, filled with pieces of CaCl 2 . To this tube is 
joined by a short rubber connection the bulb-tube 
P, known as a Liebig potash bulb, and to this is 
joined a second smaller bulb-tube C' filled with 
CaCP. Through stopper 4- passes the inlet tube 
with rubber tube and spring clamp 6. The rubber 
tube leads to a holder for air with tubes for drying 
and purifying the air. The tubes are filled with 
Na(HO) in pieces to retain CO 2 , which is always 
in the air, and CaCl 2 to take up the moisture. 
The bulb P is partly filled with a 1:3 solution of 
NaHO in water. First we weigh the tube C by 
itself, and P-f C' together. During the process of 
weighing, the tubes C, P, C' are air-tightly closed 
by means of pieces of rubber and glass rod. Let 
the weight of C= a grams, the weight of P + C' == 



268 CHEMISTRY SIMPLIFIED. 

b grams. After all is again joined, open the clamp 
6, so that bubbles will be seen to rise in the liquid 
of P; the level in the farther bulb will rise until 
the bubbles can pass from the middle bulb through 
the joining neck. The bubbles should pass at the 
rate of one per second. Now we place a sheet-iron 
diaphragm in the furnace, astride the tube 2, just 
where the copper gauze begins, heap in first some 
ignited pieces of charcoal, then black pieces, and 
help the fire by gentle fanning. When the tube 
and gauze are red hot remove the shield or dia- 
phragm 2 inches to the left, and even up the coal. 
Every 10 minutes move the shield 2 inches further 
to the left, until we have reached the left end of the 
furnace, and then keep up a uniform red heat for 
10 minutes more. The cellulose is burnt up by 
this time, and the products of the combustion have 
been carried forward into the absorption tubes by 
the slow current of air. It may be that a small 
quantity of water still lingers this side of C. We 
draw T to the right to heat the end of it and cause 
the water to evaporate and to get into C. Now we 
detach first P from (7, put on the glass plugs, then 
draw out C and put on the plug. Then we weigh. 
The weight of C will now be a' grams, that of P + C' 
= b f grams ; the increase in C being due to water, 
the increase in P + C' being due to carbon dioxyd. 
Having started with 0.5 gram of cellulose 

a' _ a will be 0.2772 IPO 
b' b will be 0.8147 CO 3 



CARBON COMPOUNDS. 269 

TT 2 1 TT2H 

H 2 =_ ; hence 0.2772 H 2 = 



H 2 O 9' 9 

0.0308 H 

c& = n ; c = n c 2 ; hence - 8147 c 2 = 

0.2222 C 
0.5 gr. cellulose contains 0.2222 C ;' 0.0308 H ; 

0.2470 0. 

For the difference 0.5 0.2222 0.0308 = 0.2470 
must be oxygen, we have proved by the experi- 
ments above, that cellulose can contain only C, H, 
0. Expressed in percentage we get 

C = 44.44 

H - 6.16 

49.45 

Dividing these percentages by the atomic weights 
we obtain the atomic quotients thus, 
44.44 



12 
6.16 



= 3.7033 
- 6.1600 



1 

49.45 

-jg- = 3.0906 

We reduce these to units of oxygen, because oxygen 
has the smallest quotient, 
3.7033 



3.0906 
6.1600 
3^906 
3.0906 
3.0906 



= 1.198 or 1.20 
= 1.993 or 2.00 
= 1.000 or 1.00 



270 CHEMISTRY SIMPLIFIED. 

and obtain the nearest whole numbers which are 
12 20 10. But these numbers are divisible by 
2, therefore in the molecule of cellulose the three 
elements are contained in the ratio 
C 6 H io 5 = cellulose 

The weight of the molecule is 6 X 12 + 10 X 1 + 
5 X 16=162 

The first point striking our attention is that hydro- 
gen and oxygen are in this molecule exactly in the 
same ratio as that of water, so that we might write 
the formula C 6 (H 2 0) 5 , a hydrate of carbon. As there 
are a number of other bodies of this type it is well 
to distinguish them as a group by the name carbon 
hydrates, although ' we know well that H -f are 
not grouped in the molecule as H 2 0. For if they 
were, the cellulose would have to part, on heating, 
into C -f H 2 O, but it does so only in part as we 
shall see presently in the destructive distillation of 
wood. 

Some of the Properties of Cellulose or Wood Fiber. 

It is colorless or white. It is insoluble in water, 
in alcohol, in ether, whether cold or boiling. It is 
not affected by dilute solutions of the alkalies and 
acids at ordinary temperatures. Persistent boiling 
with these dilute agents slowly dissolves it. 

Vegetable parchment = papyrine, results when good 
filter paper is immersed for a few seconds into a 
mixture of 1 vol. cone. H 2 S0 4 + J vol. water. 
After withdrawing the paper from the acid it must 



CARBON COMPOUNDS. 271 

be washed out with much water and finally with 
a 2 per cent, solution of ammonium hydrate, to re- 
move every trace of adhering acid. It is then dried. 
After drying, water has little effect upon it ; it does 
not blot, and resembles dried skin. 

Nitro-cellulose, gun-cotton, C 6 H\N0 2 ) 3 O 5 , tri-nitro- 
cellulose. Let cleansed, dry cotton be' immersed for 
5 minutes in a liquid consisting of 1 vol. fuming 
HNO 3 + 3 vols. cone. H 2 S0 4 . Let it then be 
squeezed out and thrown into much cold water and 
washed until all acid reaction has disappeared. On 
drying we find that externally the cotton has re- 
tained shape, color and cell structure; its weight 
has increased 50 per cent., its tensile strength has 
considerably decreased. But it has acquired the 
faculty to explode with great force, w r hen struck 
a sharp blow with a hammer upon an anvil. Ignited 
by a match it burns instantly with a flash but with- 
out detonation. If the material be put into a closed 
space, such as a drill hole, and then ignited it will 
rend the enclosing material'same as gunpowder. 

Explanation. Analysis shows that the composi- 
tion of the altered cotton leads to the formula 
C 6 H 7 N 3 11 , the substance having become a nitro 
body. Three atoms of hydrogen have been removed 
from the cellulose and in their places have been 
substituted 3N + 60 = 3N0 2 . We can represent 
this graphically thus : 

_H_ 
C 6 H 7 ^ -H- 5O 5 , Cotton or cellulose ; 



272 CHEMISTRY SIMPLIFIED. 




Trinitrocellulose. 



The change can be represented by the equation : 

3 5 + 3H 2 



There is no evolution of gas. The water is taken 
up by the concentrated H 2 S0 4 and the UNO 3 
suffers no loss of energy through dilution. If ordi- 
nary cone. HNO 3 be taken, a different product re- 
sults. It appears the same to the eye, but dissolves 
in a mixture of alcohol and ether. The product is 
essentially C 6 H 8 (N0 2 ) 2 5 == dinitrocellulose. It 
bears the name pyroxyline and its ether-alcohol solu- 
tion is called collodion. Collodion produces a trans- 
parent film when allowed to run over a clean glass 
plate. This is the film used in the wet plate process 
of photography. It is also used in surgery to keep 
a fresh wound from contamination with the poison 
microbes of the air. 

Gun-cotton (trinitrocellulose) as an explosive. The 
products of the detonation of gun-cotton are CO + 
N -h CO 2 + H 2 0. Two molecules will give 9CO + 
3C0 3 +6N + 7H 2 0. 

1 molecule C 6 H 7 (N0 2 ) 3 5 weighs 72 + 7 + 138 
+ 80 = 297. 

2 x 297 = 594 grams of C 6 H 7 (N0 2 ) 3 5 give 
250CO + 132C0 2 + 84N + 126H 2 0. 1 gram of 
C 6 H 7 (N0 2 ) 3 5 gives 0.4242CO + 0.2222C0 2 + 
0.1414N -f 0.2121H 2 = 0.9999 substance. 



CARBON COMPOUNDS. 273 

Since 1 c.c. CO weighs at C. (760 mm) 

= 0.00125 gr. 

1 c.c. CO 2 =0.001977 gr. 

1 c.c. N = 0.001256 gr. 

1 c.c. H 2 (steam) at 100 C. = 0.000589 gr. 
Therefore 0.4242 gram CO occupy the space of 
0.4242 



0.2222 gram CO 2 occupy the space of 
0.2222 
000199~ 

0.1414 gram N occupy the space of 
0.1414 

. I ] X ft p 

0001257 

0.2120 gram H 2 occupy the space of 

- 212Q = 360 c.c. 
0.0005896 

But the volume V, equal to (339 + 112 + 113) = 
564 c.c. of CO + CO 2 + N at C., will be at 100 
C. equal to 564 + (564 X 0.37) = 772 c.c., and the 
total gas at 100 C. = 772 + 360 = 1132, or over 
three times the volume of the gases which are evolved 
from 1 gram of black powder. Assuming that 1 
gram of gun-cotton fills the space of 1 c.c., and that 
the sensible temperature of the gases after explosion 
be 1000 C., after proper deductions for loss, the 
pressure exerted by the gases will then be (for the 
permanent gases alone) 772 -f- 285 = 1057 atmos- 
pheres per 6 sq. centimeters. For the aqueous 
vapor we get, at the least, a pressure of 360 atmos- 
18 



274 CHEMISTRY SIMPLIFIED. 

pheres per 6 square centimeters, a total of 1417 
atmospheres pressing upon 6 square centimeters. 1 
square inch = 6.452 square centimeters. Hence we 
get 1417 X 15 = 21255 Ibs. pressure on one square 
inch nearly. When used in underground workings 
the air becomes poisoned, partly by the carbon 
monoxyd, but chiefly from the brown niter gases, 
NO 2 . This shows that the explosion does not break 
up the gun-cotton always alike. NO forms instead 
of CO 2 , and then after explosion, when the gases 
mix with the air, NO becomes NO 2 . 

THE ACTION OF HEAT UPON CELLULOSE. DESTRUCTIVE 
DISTILLATION OF WOOD. CHARCOAL MAKING. 

Let a splinter of dry wood be heated over an open 
flame, in a narrow glass tube which has been closed 
at one end. We notice the wood burning first yel- 
low, then brown, then black, while a dense yellow 
vapor is evolved. The vapor condenses partly into 
a brown-red liquid. The vapor escaping from the 
tube bums, is inflammable. In order to study each 
of these three main products, one must repeat the 
experiment on a larger scale, and so that the pro- 
ducts may be completely collected, especially the 
gas. The following arrangement of apparatus Fig. 
76 will answer and yet be simple. 

A strong glass tube T closed at one end lies in a 
furnace Fas in the previous experiment. The tube 
holds a stick of dry wood 20 grs. in weight. The 
tube T reaches into a glass receiver R, home-made 
from a large test-tube. A rubber band 2 makes this 



CARBON COMPOUNDS. 



275 



connection tight. B is an open bell jar with stop- 
cock 6 connected by angle tube 5 and rubber tube 4 
with the receiver. The bell stands in a large beaker 
glass H, two-thirds full of water. With open stop- 
cock 6 and sucking at the rubber tube 4 the bell is 
filled with water ; the stop-cock 6 is then closed. 
Live charcoal is piled into the furnace to the left of 
the shield S. The distillation begins ; the gases 
drive the air out of 2 and R. As soon as the yel- 
low cloud fills R t we connect the rubber tube 4 with 
R, and by so doing will have fair assurance that 

FIG. 76. 




whatever gases are now collecting in B will have 
been produced from the breaking up of the cellulose 
molecule. Care is taken to give T a slight inclina- 
tion forward, to wit, by raising the closed end. The 
condensed liquid will then run into R, and not back- 
ward, where it might cause a breaking of red-hot 
glass. When the flow of gas becomes slower we 
move S into the position 7, and fill in fresh live coal. 
Be watchful of the glass tube T. If its temperature 
rises above cherry redness it is apt to bulge out, be- 
come weak and perforated, an event which prema- 



276 CHEMISTRY SIMPLIFIED. 

turely ends the experiment. We maintain the heat 
until the volume of gas in B becomes stationary. 
All this time we have been lifting the bell B so that 
the liquid inside remained higher than the outside 
level, which means a steady suction or partial 
vacuum. The latter is an additional precaution 
against the distention or bulging of the softened, 
red-hot glass tube. If now a mark is made 
upon the bell to indicate the height of the level 
when water stands evenly inside and outside, (the 
coal being removed and the tube having acquired 
ordinary temperature) we will have the volume of 
gas V which can be obtained from the distillation 
of 20 grams of dry wood. We then close the stop- 
cock 6 1 , and set aside the bell and holder. We detach 
the receiver and weigh it with contents, then with- 
out contents, and thus find the weight of the latter. 
Lastly we take out the charcoal from the tube and 
find its weight. 

(1) The charcoal. Varies in color from red-brown 
to deep black, according to the temperature. The 
higher the heat, the deeper the black. The brown 
charcoal is imperfectly done, as shown by the fol- 
lowing analysis: C, 70.4; H, 4.6; 0, 24.2; ashes, 
0.85. 

But even the hardest and blackest charcoal is not 
all carbon; temp. 1300 C. : C, 90.8; H, 1.6; 0, 
6.5 ; ashes, 1.15. 

(2) The brown liquid. Even in the receiver, R, 
one notices that the liquid consists of two parts ; 
one watery, mobile, brown liquid, we designate pyro- 



CARBON COMPOUNDS. 277 

ligneous acid ; the other portion, dark black -brown, 
viscous, not very liquid, shall be named wood-tar. 
Both portions possess a penetrating, peculiar, not 
unpleasant odor the odor of smouldering wood, 
empyreumatic odor from Greek, fire odor. The taste 
of both portions is bitter, unpleasant. Some of the 
tar collects over the pyroligneous acid, some at the 
bottom, and some remains suspended. This proves 
tar to be a mixture of several bodies. The pyroligne- 
ous acid is so named because of its acid reaction on 
litmus, and from pyro, fire ; lignum, wood, firewood 
acid. Let the two portions be separated by filtering 
through charcoal powder which lies in a cotton- 
plugged funnel. The tar particles adhere to the 
charcoal, pyroligneous acid passing through. We 
add solution of NaOH until the acid reaction on 
litmus ceases. We bring the liquid into a flask with 
perforated stopper, a glass tube, bent over so as to 
connect with a cooling tube, passing through the 
hole. On boiling, a colorless liquid passes over 
which shows the strong odor still very markedly. 
But the liquid is inflammable ; its specific gravity 
is less than water. This substance is known as 
wood spirits. A closer study reveals that this liquid 
may be separated by fractionating into water plus 
concentrated spirits, and the latter again fraction- 
ated gives the pure wood spirits, also known as 
wood akohol, methyl alcohol. It is a very mobile 
liquid, which boils at 60.5 C. Its specific gravity 
at 4 C. = 0.81 (water = 1). Mixes with water in 
all proportions. Burns with bright bluish hot 



278 CHEMISTRY SIMPLIFIED. 

flame. It is very useful in the chemistry of dye- 
stuffs as a solvent and modifying agent. 

The analysis gives for it the symbol CH 4 0. We 
evaporate the remaining liquid in a boiling flask to 
dryness. A black mass results which we calcine in 
a porcelain dish, that is heated over the open flame 
until the black color has become grey-oily; gases and 
vapors pass off. We return it then to the distilling 
flask with H 2 S0 4 and water. A colorless liquid 
condenses, very mobile, very sour. Because, we 
reason, if the original acid in the pyroligneous liquid 
be HA then by adding NaHO we get NaA + H 2 O. 
Then acting with H 2 S0 4 must give us 
2NaA + H 2 S0 4 ==-Na 2 S0 4 + 2HA (the new acid). 

The analysis gives for HA the formula 
H.C 2 H 3 2 . We name it acetic acid from acetum = 
Latin for vinegar, for the acid resulting from the 
fermentation of fruit juices has the same composi- 
tion and properties as this wood acid. Acetic acid 
H.C 2 3 O 2 short symbol, HA is a liquid, colorless 
mobile; with very sharp odor. At C. this liquid 
acid becomes solid, crystallizes ; and strangely these 
crystals only melt at 16 C., having sp. gr. 1.0553. 
This most concentrated acid is known as glacial 
acetic acid. When water is mixed with this glacial 
acid, the specific gravity increases although the 
water is less heavy. This can only be explained 
by assuming that the molecules of the strong acid 
are in their free state farther apart than in the 
water-mixed state, that the addition of water causes 
the drawing together of these molecules. The spe- 



CARBON COMPOUNDS. 279 

cific gravity increases until 22 parts of water have 
been added to 78 pts. of acid, when the specific 
gravity = 1.0748. Beyond, with more water the 
specific gravity decreases. A mixture of acid 43, 
water 57 has again the same specific gravity as the 
pure acid. HA forms salts with all metals except 
gold; and the normal salts are all easily soluble in 
water. The acetates are much used in dyeing, espec- 
ially Pb(A) 2 and A1(A) 3 . In the manufacture of 
charcoal, the pyroligneous acid is neutralized 
with Ca(HO) 2 slaked lime, in place of Na(HO) 
because cheaper. Hence the crude Ca(A) 2 is the 
product of commerce, shipped from the woods to 
the large cities, where the acid itself is then dis- 
tilled. 

(3} The tar or wood tar. It has been stated above 
that by this name is meant the oily dark-colored 
material which either rises as a scum to the top of 
the wood acid, or sinks to the bottom of the latter. 
We separate it from the watery liquid and proceed 
to its examination. The expression Tar-jacket for 
a sailor came in use through someone's observing 
that the steeping of wood or linen in tar, made 
those substances impervious to water, and prevented 
both dry-rot and wet-rot (the decaying of wood). 
Hence the practice rose to soak the wooden planks 
of boats and ships with the tar, also the entire 
rigging, especially halyards and shrouds and cables, 
also the overalls of the sailors, with this strong- 
smelling material. Later on fence posts, telegraph 
poles, etc., were steeped, and lastly, railroad ties. 



280 



CHEMISTRY SIMPLIFIED. 



Evidently mine timber would be benefited by 
means of repeated coats of tar, wherever mines are 
half wet, and the timbers succumb rapidly to the 
rot, i. e., fungus and microbes. The curing of hams, 
bacon, fish, by first salting and then drying them 
out over a smoking, smouldering wood fire, is a very 
ancient practice. The tar oils condense on the sur- 
face of the meat and keep off the microbes of putre- 
faction until the meat is dried out and no longer 

FIG. 77. 




subject to the action of these organisms. Tar burns 
freely and is used as a so-called liquid fuel. Let 
the tar be heated in a retort, which is furnished 
with a thermometer, Fig. 77, i; the neck of the re- 
tort reaching by a reducer B, the tube of a Liebig 
cooler L, the joint R-N made tight by a rubber 
band. Cold water enters from a hydrant through 



CARBON COMPOUNDS. 281 

connecting rubber 1 into the cooler, the warm water 
leaving through rubber tube 2. The flame from 
burner F is so regulated that the liquid keeps gently 
boiling. We notice that the mercury in thermometer 
will be steadily rising, while a clear liquid collects 
in the graduate G. The rising thermometer can 
mean two things : (a) The tar is a mixture of 
liquids having their boiling points at different tem- 
peratures, (b) The tar is a uniform chemical sub- 
stance, which, however, breaks up by the heat into 
bodies of different boiling points. Evidently it 
makes no difference for practical purposes whether 
the truth lies in condition (a) or whether it lies in 
condition (b). If the graduate G be emptied when 
10 c.c. have been condensed, and so every other 10 
c.c. be collected separately (distillation by fractions), 
it will be found that the specific gravity of each 
fraction is higher than that of the preceding fraction, 
varying from 0.82 to 0.87. Before the Pennsylvania 
coal oil had come into general use, these tar oils 
took the place as illuminating agents, the lighter 
part going by the name of photogen, while the heavier 
part was known as solar oil. To the latter clung the 
strong penetrating odor. If this portion be shaken 
with NaOH or KOH in water-solution for some 
time, and the two liquids be allowed to stand 
quietly, they will separate, the oil above, the KOH 
water-solution below. In a separately funnel the 
aqueous liquid can be drawn off clean. We make 
acid with dilute H 2 S0 4 , and find again an oil 
separating at the top. This oil possesses a penetrat- 



282 CHEMISTRY SIMPLIFIED. 

ing odor, and a bitter astringent taste. It used to be 
called creosote, is now called carbolic acid or phenyl 
hydroxyd. The combustion analysis (refer to cellu- 
lose) gives the ratio of the elements as C 5 H 6 0, but 
because this body as we have seen combines with 
KOH, and because it also dissolves in strong H 2 S0 4 , 
we write its formula, C 6 H 5 (HO). C 6 H 5 as radical 
we call phenol or phenyl. Towards strong bases it 
acts as an acid, towards strong acids as a base. 
Thus : 

KOH + C 6 H 5 (HO) = H 2 + (KO)C 6 H 5 , .potas- 
sium carbolate. 

2C 6 H 5 (HO) + H 2 S0 4 = C 6 H 5 .H(S0 4 ) .+ H 2 - 
phenyl sulfate -1- water. 

Carbolic acid or creosote is at ordinary temperature 
a crystallized solid without color, but possessing a 
strong smell. It melts quickly into a thick oil. 
One part dissolves in 10 parts of water. It is very 
poisonous to animal life. It is used as a germ- 
destroyer, but its chief use is to act as base for 
the manufacture of picric acid. Coal-tar contains 
more carbolic acid than wood-tar. 

Trinitrop heno I, C fi H 2 ( NO 2 ) 3 OH, picric acid. Take 
about 1 c.c. of liquid carbolic acid. Pour this into 
10 c.c. of fuming HNO 3 . The action is apt to be 
violent, copious brown fumes being formed. Boil 
until brown fumes stop. Then pour liquid 
into much cold water. The water takes a deep 
yellow color and a yellow sediment falls oufr. The 
yellow substance is picric acid. Pour off the yellow 



CARBON COMPOUNDS. 283 

liquid and add to the residue again about 50 c.c. of 
water, and boil. The picric acid being more soluble 
in boiling water, a brown resin-like substance re- 
mains. As the boiling yellow liquid cools down it 
throws out yellow, scaly crystals, the picric acid; 
picros = bitter, on account of the strong bitter taste. 
Solution reddens litmus ; can be neutralized with 
KOH or NH 4 HO when yellow needles fall from the 
solution, representing the potassium, or ammonium 
picrate. Both these salts are very explosive, more 
so than the acid itself. The ammonium picrate is 
used in the smokeless powders. 



C 6 H 2 (N0 2 ) 3 HO + NH 4 HO = (NH 4 )O.C 6 H 2 - 
(NO 2 ) 3 + H 2 0. 

The solution of picric acid is used in dyeing silk and 
wool a beautiful golden-yellow color. 

Paraffin, C 11 H 36 to C 24 # 50 . On continuing 
the distillation of the tar, after the solar oil sp. gr. 
0.86, we find that the vapors condense in the tube to 
LI semi-liquid, buttery product, and finally they con- 
dense to a rigid solid. By pressing the semi-liquid 
between paper, we find scaly crystals in the paper 
and a liquid pressed through the latter. The liquid 
is known as paraffin oil for lubrication, and the crys- 
tals go under the name of paraffin. So also does the 
material which solidifies at once into a rigid solid. 
After refining, the paraffin is used for imitation ivax 
candles. As given above, the solid is not a homo- 
geneous body, but a succession of hydrocarbons of 
the general formula C n H 2n+2 . The melting-point is 



284 



CHEMISTRY SIMPLIFIED. 



the arithmetical mean of those of the different mem- 
bers. 

Paraffin is useful in the laboratory to soak corks 
in, to paint over labels with, and in fact to cover all 
metallic apparatus which is not subjected to heat, 
for it is a body very indifferent to chemical action. 

Only hot concentrated HNO 3 or hot H 2 S0 4 will 
decompose it. 

Examination of the ivood gases. In this examina- 
tion we make use of the solubilities of the gases in 

FIG. 78. 




liquids or their absorption by solids. The sum of 
the processes we designate as gas analysis. The most 
convenient apparatus for the purpose has been de- 
signed by Professors Winkler and Hempel ; though 
a number of others of no less ingenuity have con- 



CARBON COMPOUNDS. 285 

tributed their share. In Fig. 78 B represents the 
burette or measuring vessel, a cylindrical glass tube 
graduated into 100 c.c. and 4- c.c. The tube stands 
in the cast-iron foot F so that it will not be upset 
easily. .Fis bored out at 1 to admit a small tubu- 
lature to which a strong rubber tube is wired. The 
stop-cock S has a capillary perforation which leads 
to the capillary tube 3. With the latter is united 
by the wired rubber 5 the capillary transfer tube 4 in 
form of a double L. The hollow volumes or canals 
of both tubes do not exceed 0.01 c.c. L, Fig. 78, is 
the level tube in foot .Pto which the rubber tube from 
foot of B is joined and wired at 6, The rubber tube 
should be as long as the cylinder is high, so that the 
foot of one cylinder may be raised to the top of the 
other cylinder. This arrangement permits the read- 
ing of the gas volume under constant pressure, i. e., 
the pressure of the atmosphere, and in so much as 
the temperature of the room does not materially 
change during one set of absorptions, we may set 
down the temperature as constant and thus avoid the 
reductions of volumes to C. and 760 mm. 

Fig. 79 shows the pipette or absorption vessel for 
absorbing CO 2 . The glass bulb, C, is seen filled 
with small coils of iron wire gauze, which are in- 
troduced by means of the wide mouth and stopper 
at S. This bulb communicates through tube, 1, 
with the reservoir-bulb, D, which is open at the top. 
A capillary glass tube leads in single loop to the 
rubber tube, 3, the latter being closed by the pinch- 
cock, 4.. The whole combination is fastened to the 



286 



CHEMISTRY SIMPLIFIED. 



iron frame, F, which has taken the place of the 
former wooden frame, the spilling of the strong 
agents over the wood making it soon unsightly and 
insecure to stand up. The absorbing liquid is a 
solution of 15 grams of KOH or NaOH in 50 c.c. of 
water. This solution is poured into D (pinch-cock 
being open) ; the air is forced into D, the pressure 
driving the liquid gradually through the capillary 

FIG. 79. 




tube leading to 3, until the liquid appears at the 
top of 3. The coils of iron wire gauze being moist- 
ened with the alkali, expose a very large surface to 
the gas and cause an almost instantaneous absorp- 
tion of the CO 2 . 

Fig. 80 represents a double pipette, to be used 
for liquids which are easily deteriorated by the 
oxygen of the air, like potassium pyrogallate for 
oxygen, and acid or ammoniacal solution of Cu 2 Cl 2 
for CO. The capillary is provided with a pinch- 
cock, as in previous form. Being filled as the 



CARBON COMPOUNDS. 



287 



figure indicates, the bulb, A, being the absorp- 
tion bulb, is quite full, whilst the liquid rises in B 
only to the lower outlet. C contains the same 
liquid, but only partially filled. Hence the air has 
no access to the liquid in A and B, and can spoil 
only the liquid in C and D. When the gas enters 
A through the capillary, it pushes the absorption 

FIG. 80. 




fluid into B, which is large enough to hold the entire 
volume of A. As the fluid rises in B, the nitrogen 
forces down the liquid in C until the bubbles can 
pass into D, and when, after the absorption, the gas 
leaves A returning to the burette, air will bubble from 
D into C. But it loses its oxygen to the liquid, and 
thus there is only nitrogen between the levels in B 
and C. In others words, C and D are simply traps. 
The pipette, Fig. 81, serves when the absorption 
liquid attacks metal and yet a large wet surface is to 
be exposed to the gas ; using, for instance, oil of vitriol 



288 



CHEMISTRY SIMPLIFIED. 



or bromine water. Here the bulb B is filled with glass 
beads. These were put in by the glass blower before 
he narrowed the neck which unites B to A. Through 
the glass blower's dexterity we are thus in posses- 
sion of an elegant set of apparatus. But suppose 
one of the pipettes meets with disaster just when 

FIG. 81. 




you need the set most. What then? A week 
would pass before you get a duplicate from the 
dealer. Fig. 82 shows how an equivalent may be 
made quickly by means of 2 Erlenmeyer flasks, E, 
E'. The flasks should hold 200 c.c. each. The 
flasks have doubly-perforated stoppers. Through 
one of the holes passes the siphon tube 1, \" inside 
diameter, reaching to near the bottom of both flasks. 
Into the second hole of stopper E is stuck a piece of 
thermometer tube there are always broken ther- 
mometers about a laboratory. The thermometer 
has a capillary canal, just what we need. The piece 



CARBON COMPOUNDS. 



289 



is about 2J inches long; the sharp edges are rounded 
over a flame; the tube is stuck in so that the lower 
edge is flush with the stopper, avoiding any spaces 
for the lodging of gas. A piece of rubber tubing 
(black) 2" long is wired over the upper end and a 
pinch-cock clamped just above the end of the cap- 
illary tube. Through the second hole of stopper 
E' passes a short glass tube #, " inside, to which a 
piece of rubber tubing 4- is attached (for conveni- 
ence in blowing air). E may be filled with coils of 
iron wire gauze, or with glass beads to give absorb- 

FIG. 82. 




ing surface. In filling with absorption-liquid re- 
move stoppers, pour into each flask so that the 
levels are even and nearly up to J vol. of flask. 
Then insert stoppers very tightly, open pinch-cock 
and blow into rubber tube 4- unt il the liquid ap : 
pears above the pinch-cock; then close the latter 
and E will remain full, ready to receive the gas. 
The two flasks form one unit. To prevent deteri- 
oration of stoppers, they should be coated with 
19 



290 



CHEMISTRY SIMPLIFIED. 



molten paraffin and after pressing them into the 
necks, copper wire should be stretched across the 
tops to prevent their slipping out, as the paraffin is 
a splendid lubricator. Such an apparatus gives 
perfect results. If the measuring cylinder, the 
burette, should break, you can construct a very 
satisfactory substitute as follows : Make a square 
block of wood 4" side length and 3" thick. Bore 
an inch hole clear through the center and a slot S, 
Fig. 84, clear through the side, J" wide. Then nail 

FIGS. 83, 84, 85. 




a square of heavy sheet lead (J" thick) across the 
bottom as at L, Fig. 83. The top edges of the block 
should be bevelled. This will give you an excellent 
stand, or foot for the burette. Select a piece of 
glass tube as nearly cylindrical as possible of from 
f " to J" inside dia. about three feet long. Scrub 
the inside of the tube with warm NaOH solution to 



CARBON COMPOUNDS. , 291 

remove any fat; then rinse and dry. Round off 
the sharp edges of one end, fit a cork or rubber 
stopper with one hole, into which you have put a 
J" glass tube, bent as shown at t, Fig. 83. Close t 
with a bit of wax plug ; then set it into the foot, 
after first sticking some cotton into the hole. Fill 
with water to about 1 inch above the wood and 
scratch with a file a line ra at the upper rim of the 
meniscus. Weigh into a beaker glass 100 grams of 
water not nearer than 10 mgr. which is equal to 
0.01 c.c. Pour this water into the tube. But re- 
member that the beaker as well as the tube should 
be moistened before either weighing or pouring, for 
some water will adhere to the glass wall, thus caus- 
ing an error. 

Now make another scratch at the upper rim of 
the meniscus ra'. Now empty the tube and cut off 
the latter 1" above ra' at ra", round off the sharp 
edges over the flame and fit a stopper into which 
you have stuck 2" of thermometer tube, the edge of 
the latter being flush with the under side of the 
stopper. Fasten a strip of white writing paper 
(several lengths may be stuck together) and lay off 
upon it the distance ra-ra/ accurately. Divide this 
space into 100 equal parts, and -each part into fifths. 
Number every 10 c.c. and draw out in india 
ink, cut it into a strip \" wide, paste upon the tube 
with a mixture of starch paste and liquid glue. 
Remember that the wet paper expands and that the 
two end marks will fall beyond the scratches on the 
glass. In drying the contraction will bring the 



292 CHEMISTRY SIMPLIFIED. 

paper back to the mark. When dry cover the back 
of the paper with molten paraffin, but not the glass. 
Press down the upper stopper so that its under face 
coincides with the zero mark m' as shown in figure ; 
the remainder of tube being already cut off. Now 
fasten the tube into the foot by pouring liquid wax 
into the narrow ring between glass and wood, the 
slot having been plugged with wood. Finally put 
2" of rubber tube upon the capillary and a pinch- 
cock. Thus the top of the burette will look as shown 
in Fig. 85. It is in every respect as good as a fully 
glass blown instrument, except that the scale is not 
apt to be quite as accurate, yet sufficient for all 
technical purposes. Never omit the wiring of the 
rubber, for if the rubber slips off the examination is 
lost. The analysis of our wood gas can now be pro- 
ceeded with. 

Note. All gases are more or less soluble in water. 
To avoid the error from this source completely the 
gas must be caught over mercury and measured 
over mercury level glass and burette are filled with 
mercury. The error may be overcome partially, by 
saturating the water in the burette with the gas, i. 
e.j shaking the water with the gas, and the same 
with the absorbing liquids. The most soluble in 
water is CO 2 , hence it is well to let water in burette 
saturate itself with CO 2 , before the analysis. 

To fill the burette with gas from the holder will 
be the first operation, taking advantageously just 
100 c.c. to avoid figuring. In Fig 86 the arrange- 
ment of apparatus is shown in the moment of trans- 



CARBON COMPOUNDS. 



293 



fer, when the gas has passed from B into the ab- 
sorption bulb A, and the liquid from the latter into 



FIG. 86. 




the tank bulb C. Stop-cock 1 and pinch-cock 2 are 
now closed ; the level cylinder dropped upon the 



294 CHEMISTRY SIMPLIFIED. 

table. The operator seizes the frame of the pipette 
and the scaffold upon which the pipette stands, with 
both hands and shakes so that the liquid in A 
splashes all about the bulb and remains in contact 
with the gas ; at the least for 5 minutes. Then open 
the cocks and the gas will flow back into B where 
the vol. is recorded. 

The order in which the absorbents are applied is : 
(1) KOH for CO 2 : (2) pyrogallate for O ; (3) fuming 
sulfuric hydrate (oil of vitriol) for the heavy hydro- 
carbons ; (4) cuprous chlorid in ammoniacal or in 
HC1 solution for CO ; (5) spongy metallic palladium 
forH. 

In applying these to our gas, the gas from cellu- 
lose or wood, we find a shrinkage of volume after 
each application, except for oxygen. This element 
is only found when air has become mixed with the 
gas. The largest shrinkage is that due to hydrogen. 
After the absorption of H by palladium there is 
still a large volume of gas left. It must be, there- 
fore, a gas which we have not met with before. We 
find it to be highly inflammable, and it burns with 
a pale, nearly colorless flame, if ignited at a platinum 
tip (for if the flame comes in contact with glass, the 
former is always of orange-yellow color from the 
sodium in the composition of the glass). 

MARSH GAS, METHANE, METHYLHYDRID, CH 4 . 

When the gas in question burns we can easily 
demonstrate the forming of CO 2 and water, hence the 
gas must contain C and H, but might also contain 0. 



CARBON COMPOUNDS. 



295 



To get at the relative proportions of C -f H we 
burn a measured volume within a closed vessel, so 
that none of the products can escape. Heretofore 
we used a simple eudiometer, the gas being above 
mercury. Hempel has constructed a pipette for 
this purpose. Fig. 87 shows this piece of apparatus. 
The bulb A is shaped into a neck* or dome and 
thence is fused to the capillary. Into the neck two 

FIG. 87. 




platinum wires are inserted by fusion, the same as 
in the eudiometer ; these wires lead to the pole 
binders of an induction coil, thence to the battery. 
A being completely rilled with water, we transfer 
from the burette, say 10 c.c. of gas, into A. We 
cannot use pure oxygen, because the explosion might 
easily shatter the relatively thin and weak bulb. 
We take air instead, thus diluting the effect of the 



296 CHEMISTRY SIMPLIFIED. 

explosion by means of the inert nitrogen. 100 
volumes of air contain 20.9 volumes 0. As regards 
the volume of air to be admitted we can reason 
thus : If the total 10 c.c. were carbon gas then we 
would need 20 c.c. of 0, for 1 vol. of CO 2 contains 
\ vol. C + 1 vol. 0. If the whole 10 c.c. were 
hydrogen, then we should need 5 c.c. of oxygen, a 



total of 25 c.c. of oxygen or _ = 119 c.c. of 

L\ 

air. As both C and H are present, this volume of 
air will surely give us an excess of oxygen. Let 
this volume of air be transferred from the burette in 
2 installments, then let the cock S be closed. The 
expansion of the gases, consequent to the explosion, 
will then throw itself upon the bit of rubber tube, 
between the pinch-cock and the capillary, hence 
the rubber tube must be very strongly wired upon 
the glass, or the rubber will be surely flung off as a 
bullet from a gun barrel ; the pinch-cock also must 
be wired so that it cannot open under the pressure. 
A screw clamp is, therefore, preferable to the spring 
clamp. The rubber tube should be frequently re- 
newed, as frequent expansion is apt to destroy the 
elasticity of the rubber. Let the pipette be forcibly 
shaken to effect a mixing of air and gas. Make 
connection at commutator ; the spark is seen passing 
between the platinum wires, but no explosion occurs ; 
it should take place and mostly does take place. 
When it does not occur the cause of failure lies in 
too much dilution, the 10 c.c. of gas taken having 
already much nitrogen admixed. Under these cir- 



CARBON COMPOUNDS. 297 

cu instances we generate in a voltameter fulminating 
gas (0 + 2H), and let, say, 10 c.c. into A. Explosion 
is now certain ; the fulminating gas will act the 
same as the cap attached to the fuse, when a charge 
of dynamite is to be exploded. In our meaning 
the term explosion = instantaneous oxydation or 
combustion, or burning of C and H. A slower 
burning may be called a fire. The volume of ful- 
minating gas need not to be measured accurately 
because it simply disappears in the explosion as 
water, whose volume is trifling in comparison to 
the volume of the gas. After the explosion we 
open cock S and note a strong current setting from 
B into A, and this means disappearance of a certain 
portion of the gas. The disappeared portion we 
name the contraction, = C', in this case 30.1 c.c. 
The volume of the gas mixture V, before the ex- 
plosion was 

V = G + A (G = gas 10 c.c. ; A air 119 c.c.) 

V==10H-119 = 129c.c. 
After the explosion 

V = V C'' (contraction) = 129 30.1 = 98.9 
C' itself is made up of H -f which disappeared as 
IPO. 

2C / /3 = H; C'/3 = 0. 

We pass the mixture into the KHO pipette and find 
a shrinkage of 9.8 c.c., which must represent the CO 2 
formed from 10 c.c. of the gas. But 1 volume CO 2 
contains 1 volume 0, hence 9.8 c.c. of the 24.9 c.c. 
of added went into the forming of CO 2 ; which 



298 CHEMISTRY SIMPLIFIED. 

means that 10 c.c. of the gas contained 5 c.c. or ^ 
vol. carbon vapor. We transfer the gas into the pyro- 
gallate pipette and shake 10 minutes to absorb the 
remaining oxygen. 

We find shrinkage = 5.1 c.c. oxygen ; hence, de- 
duct from total oxygen = 24.9 c.c. 

Consumed for CO 2 = 9.8 c.c. 

Remaining oxygen = 5.1 c.c. 



14.9 

Therefore in contraction C' enter 24.9 14.9 = 10 
c.c. of 0. And as hydrogen = f C' ; ozygen JC' ; the 
10 c.c. of correspond to 20 c.c. of hydrogen, or if the 
original 10 c.c. of gas be made == 1 vol. it follows 
that 1 vol. of our unknown gas contains J vol. C 
+ 2 vols. H ; or 1 vol. C + 4 vols. H and its formula 
or symbolic expression is 

CH 4 . 

Here we have a body representing a compression of 
2.5 : 1 ; 5 volumes of C + H compressed into 2 vols. 
CH 4 . We have not had, therefore, a similar com- 
pound. Nevertheless the fact is proved by the 
specific gravity which is by calculation 

J volume of carbon vapor = 0.4146 
2 volumes of hydrogen = 0.1382 

0.5528 

Several experimenters have found by independent 
methods, that is, both by weighing the gas, and by 
its velocity of diffusion, the number 0.5589 which 
is very close to the calculated figure. The name 



CARBON COMPOUNDS. 299 

marsh gas (sumpf gas in German) refers to the evolu- 
tion of this same gas from swampy meadows where 
it sometimes gives rise to the peculiar phenomenon 
of the ivill-of-the-wisp (irr-iicht = erring or wander- 
ing light), when by accident the gas becomes in- 
flamed at one spot and the pale flame, then setting 
fire to the adjacent bubbles thus produces the 
impression of a wandering or jumping flame, once 
thought to be spirits. In the summer months the 
gas always comes abundantly when the mud in 
swamp rivers is disturbed or poked into. 

Marsh gas has neither odor nor taste. Mixed with 
air it causes no ill effects when breathed, is there- 
fore not a poisonous gas such as CO, or a suffocating 
gas such as CO 2 . 100 volumes of water absorb at 
20 C., i. e., the ordinary temperature of the air, 3.5 
volumes of marsh gas. 

When mixed with 8 to 10 volumes of air, or 2 
volumes of oxygen, the gas explodes with great 
violence ; but the temperature at which it ignites is 
higher than that at which hydrogen or hydrogen 
sulfid explode. These gases require only low red 
heat, while marsh gas requires yellow or white 
heat, showing that the elements C + H cling very 
strongly together. 

1 volume CH 4 + 3 or 4 vols. air does not explode ; 
with 1 vol. CH 4 -(-5 J to 6 vols. air the explosion is weak. 
And so again with 14 volumes of air, the explosion 
is weak ; with still more air the CH 4 merely burns 
over the flame of a candle or lamp no explosion. 
Now all this is knowledge of extreme importance to 



300 



CHEMISTRY SIMPLIFIED. 



the engineer who engages in coal-mining. For CH 4 is 
the gas which issues from the fissures of the coal beds ; 
and causes the fire danger in those mines, from its 
life-destroying explosions. The simplest instru- 
ment for the detection of the danger, i. e., the 
presence of the marsh gas in the mine, breasts, stopes, 
levels, was devised by Sir Humphrey Davy, eighty- 
eight years ago. He it was who first inquired into 



Fra. 




the nature of a flame and thus discovered a means 
against the ignition of the inflammable mixture of 
air and marsh gas. Let A, Fig. 88, be the basin of 
an ordinary oil lamp with a wick holder and wick 
4; the oil level at 3, the flame 1. B is fine mesh 
wire cloth made into a truncated cone and the cone 
is held by the brass ring 8. Thus no air can get to 



CAKBON COMPOUNDS. 301 

the flame unless it pass through the gauze, and the 
product of the combustion must also pass through 
the gauze, since the top of the cone is closed by 
gauze. If the air contains CH 4 admixed, the flame 
begins to tremble, becomes longer and a bluish 
mantle forms around it. The whole interior may 
be filled with such a blue flame. This is due to 
the fact that with the deficiency of air the carbon 
only burns to CO and not to CO 2 . But why does 
not the flame ignite the outside gas mixture? 
Simply because the wire gauze absorbs the heat so 
quickly that the temperature outside of it is too low 
to ignite the gas. The wick requires trimming from 
time to time and snuffing. These operations are 
performed with the wire 2, which passes through 
a stuffing box in the bottom of the lamp. The 
gauze must never be removed inside of the work- 
ings. Unfortunately the light given by such an 
affair is very weak and thus the men are tempted 
to remove the gauze and then comes the disaster. 

Theoretical importance of marsh gas. CH 4 may 
be written 

H 



H C H 



Four hydrogen chemical units evenly balancing 
the 4 affinity bonds of the carbon unit ; in other 
words we say the marsh gas being a fully satisfied 
chemical complex, all other combinations of carbon 



302 CHEMISTRY SIMPLIFIED. 

and hydrogen when saturated must be of the same 
type. Numerically we can express it C u H 2n + 2 . 
When we found that paraffin showed the composi- 
tion C 24 H 50 , we mean that we have here a com- 
pound built upon the type of marsh gas, yet while 
CH 4 equals a percentage composition of 75C -f 25H, 
the percentage in paraffin will be 85.3 C -f- 14.7 H. 
All the members of the marsh gas or paraffin series 
have been found either as existing in natural bodies 
or they have been prepared by artificial splitting. 
CH 4 = methane marsh gas a permanent. gas. 
C 2 H 6 = ethane, a condensible gas. 
C 3 H 8 = propane, a light liquid. 
C 4 H 10 = butane (in butter). 
C 5 H 12 pentane (five). 



C 6 !! 1 ' = hexane (six). 
C 7 H 16 = heptane (seven 



Liquids contained in 
gasoline, benzine, 



C 8 H 1! = octane (eight). and kersosene, 

C 9 H 20 = nonane (nine). also in tar. 

C io H 22 = decane(ten). J 

I I I 
C 24 H 5 = paraffin; a white, hard solid. 

With the increase of C in the molecule, rise the 
specific gravity and the boiling-point. There are 
reasons for assuming in marsh gas the existence of 
a group (CH 3 ), in which there is still closer contact 
between the atoms than in CH 4 . This latter be- 
comes then the hydrogen compound of the form 
(CH 3 )H. The group (CH 3 ) == methyl, is further- 
more to be considered a radical or complex element, 
such as (NO 3 ), (SO 4 ); only with the difference that 



CARBON COMPOUNDS. 303 

this radical is of a positive or metallic character. 
It replaces hydrogen. Every elementary molecule 
is composed of at least two atoms. That is, hydro- 
gen in the free state is not H but H 2 ; chlorine not 
Cl but Cl 2 . Then in the hydrogen molecule H-H 
we can replace 1H by (CH 3 ) as its equivalent. 



+ (CH 3 ) = = + H == CH 4 + H. 

Or, again, H 2 (S0 4 )+2(CH 3 )H=2(CH 3 ).(S0 4 )+4H; 
the latter compound is then methyl sulfate, same as 
sodium sulfate. In ethane C 2 H 6 , the older concep- 
tion saw the radical ethyl C 2 H 5 united to 1 hydro- 
gen. But it is simpler to think of it as a coalescence 
of 2 methyl groups. 



Propane, C*H* = (C*H 1 ).H=propyl hydrid = 

CH 3 .CH 2 .CH 3 . 

Two methyl groups joined by CH 2 which latter is 
the lowest member of the series C n H 2n . 

Butane, C*H l( > = (C*H)H= butyl hydrid, But 
on the methyl hypothesis there will be two combi- 
nations, which have been actually proved to exist, 
two bodies having exactly the same percentage com- 
position, but distinct properties, to wit : 

CH 3 .CH 2 .CH 2 .CH 3 , normal butane; and 

CH 3 

CH^CH 3 , iso-butane. 
X CH 3 

Such bodies as these, of equal atomic or percentage 
composition, are called isomerids. Isobutane is the 
isomerdi of butane. 



304 CHEMISTRY SIMPLIFIED. 

For pentane C 5 H 12 there are three isomerids : 
CH 3 .CH 2 .CH 2 .CH 2 .CH 3 , normal pentane. 

CH 3 

CH^CH 3 , di-methyl-ethyl-m ethane, 

X (CH 2 .CH 8 ) 

CH 3> C "^CH 3 ' tetra -methyl-methane. 
In the last we imagine a marsh gas molecule 
H H 

> C \ 
H H 

in which every hydrogen atom has become replaced 
or substituted by the methyl group. The second 
isomerid can be represented, to show the similarity, 
thus 

H- CH 3 

\Q/ 

CH 3/ X CH 2 .CH 3 . 

I beg to remind you that this so-called structural 
representation is not to mean a real picture for in 
reality we have to deal with three dimensions, not 
with two as on this sheet of paper. This is an at- 
tempt to express symbolically the difference in 
properties of the isomeric bodies. 

In the light of this exposition on marsh gas, we 
will reconsider the wood alcohol and the acetic acid. 
For the wood alcohol we had the atomic proportion 
CH 4 0, it being then suggested that this formula may 
be written CH 3 (HO), and now we see that the methyl 
alcohol is a marsh gas in which 1 H is replaced by 
the radical (HO) hydroxyl. 



CAKBON COMPOUNDS. 305 

H H 



, methyl alcohol, hydroxyl methane. 
H 



For acetic acid H.C 2 H 3 2 we can write 

FT TT 

" \Q/ > acetic acid, hydroxyl-carbonyl 

H 7 \X).OH ^ethane. 

The group CO. OH, carbonyl-hydroxyl, is mono- 
valent ; by the entering of this group into a hydro- 
carbon, the latter takes on the properties of an acid. 
The lowest form is formic acid (ant acid) CHO*.H 
which is found with the acetic acid. Here we can 
say that the group CO. OH is simply coupled with 
one H. 

WOOD OR CELLULOSE UNDER PRESSURE AND HEAT. 

If compressed cotton, or a stick of dry wood, or 
dry sawdust be enclosed in a strong glass tube as 
shown at Fig. 89, A in figure 1, and if the tube 

FIG. 89. 



C W ///////////////////// //\ 

t 

A 




be then fused together as at C, figure 2, over a blast 
lamp and the part D be pulled off, the wood A will 
20 



306 



CHEMISTRY SIMPLIFIED. 



be enclosed air-tight as in figure 3. Care must be 
had that the wall of the tube remains throughout of 
even thickness. If this tube be then placed within an 
air-bath, and the temperature be gradually raised 
to 320 C. as indicated by the air thermometer, 
Fig. 90, then it is evident that the distillation of the 



FIG. 91. 




wood proceeds under increasing pressure : First, by 
the expansion of the air ; second, by the expansion 
of the gases and vapors which arise from the wood 
at this temperature. Let the condition of things 
remain thus- for twenty-four hours. Let cool slowly. 
On examining the tube we find the wood converted 
into a jet-black shining mass ; the cellulose structure 
is effaced altogether and the resemblance to soft coal 
is unmistakable. We open the tube very cautiously 
(after taking its weight) as follows : Since the pres- 
sure is still high (presumably) a sudden breaking 



CARBON COMPOUNDS. 307 

of the tube might have a very shattering effect (like 
a boiler explosion). Therefore, we approach the 
pointed end of the tube to a strong flame, as shown 
in Fig. 91. In measure as the glass nears red heat, 
it will become soft, and expand under the interior 
pressure until at the very tip it will be blown out, 
giving vent to the compressed gases. On weighing 
the tube, now, it is found that about 2 per cent, of 
the weight of the wood has disappeared, that much 
having been converted into permanent gas. Now 
we wash carefully the mass in the tube by means of 
alcohol (to dissolve any tar-stuff), and after drying 
in a current of dry air, find again a diminution in 
the weight of about 3 to 4 per cent. Altogether 
about 20 per cent, in weight of the cellulose has 
vanished. The importance of this experiment will 
appear in the next section. 



CHAPTER XVI. 

MINERAL COAL AND ITS CHEMISTRY. 

WITHOUT mineral coal the industrial development 
of modern times would have been impossible. Some 
250 millions of tons are now mined annually in the 
United States, much more than all the other minerals 
together. The conditions under which coal is found, 
and its association with other rocks, form a subject of 
stratigraphic geology. The points to which your at- 
tention is here called refer to the properties of coal 
and the uses to -which coal can be and is applied 
owing to such properties. 

We distinguish (1). Hard coal or anthracite. 
(Greek anthras = coal.) Color intensely black, luster 
more or less bright. Fracture smooth and spheroi- 
dal. Hardness considerable ; the pick does not pro- 
duce much effect ; drilling and blasting is necessary. 

(2). Soft coal, bituminous coal, semi-bituminous, 
blacksmith coal. Much softer than anthracite, color 
black, but color of fine powder is brown. Cleaves or 
breaks into prismatic pieces. When heated in glass 
tube gives off dense yellow vapors which separate into 
a liquid and into a combustible gas, whereas anthra- 
cite gives off no vapors, and only very little gas. If 
the coal melts into a black, thick liquid, it is called 
bituminous (bitumen being the Greek word for the 
(308) 



MINERAL COAL AND ITS CHEMISTRY. 309 

natural pitch also known as asphaltum). If the coal 
merely softens in the heat, does not become quite 
liquid, then we call it semi-bituminous, (half pitchy). 

(3). Cannel coal, has a black color but differs by 
absence of luster from the ofher varieties. It breaks 
with an irregular surface. When heated it does not 
melt nor become soft, but yields both condensible 
vapors and bright burning gas . in abundance, (can- 
nel is the Scotch of candle). This coal is not as 
abundant as the other varieties and is of higher 
value, because it furnishes a larger volume of illumi- 
nating gas. It is only used for gas-making. 

(4)- Brown coal, lignite. Dark-brown color, dull 
in appearance, very soft, can be shoveled from the 
pit, shows the cell structure of wood and hence the 
name lignite (lignum = wood). When heated it does 
not soften, but gives gas and tar, although less of 
these than cannel coal ; and more water. It is usu- 
ally mixed with sand and clay to a much larger ex- 
tent than the other coals. The beds lie near the 
surface, that is, they belong to more recent geological 
times. Very abundant all over Western United 
States, Central Europe, Asia and Africa. The cities 
of Northern Germany use this material exclusively 
for fuel, on account of its cheapness. 

(5). Peat, bog, turf. Brown or brown-black in 
color, very loose in structure and crumbly. Acts 
like brown coal, when heated after having been 
dried. This material is found always in flat regions, 
where the water cannot drain off and where no 
grasses can grow on account of the wetness. But 



310 CHEMISTRY SIMPLIFIED. 

on the other hand, the different varieties of mosses 
and algae develop and grow with astonishing rapid- 
ity, one generation on top of the other, each genera- 
tion being very short-lived. Being so near the air 
the dead mosses undergo a partial rotting with the 
formation of marsh gas and carbon dioxyd. There 
are bogs known to be 50 feet thick and more. Ordi- 
narily they do not exceed 3 feet in thickness. Yet 
they furnish to many localities their only fuel Ire- 
land, Holland, North Germany near the sea. The 
higher land of Western New York, where the Hudson, 
the Alleghany, and the Delaware rivers have their 
beginning, contains many peat bogs, which are more 
or less utilized. On the flat tops of very high moun- 
tains such bogs have been found. By a washing pro- 
cess the peat substance can be somewhat freed from 
the sand, and it can then be converted into cakes by 
pressing. Such cakes, when quite air-dry will give 
a hotter fire than wood, weight for weight. 

Composition of coal. We find the ultimate or ele- 
mentary composition by the same procedure which 
we followed with the cellulose. We burn a known 
weight, W, with copper oxyd and oxygen gas and 
collect the products of the combustion, conveniently 
for measuring or weighing. We find invariably 
the same elements to wit : Carbon, hydrogen, oxy- 
gen, nitrogen, sulfur. The two latter are not in 
cellulose, but they are found in other parts of plant 
structure. Nitrogen is always contained in the pro- 
toplasm, and sulfur sometimes ; without the proto- 
plasm no plant can develop it is the blood of plant 



MINERAL COAL AND ITS CHEMISTRY. 311 

life. The seeds of plants always contain much nitro- 
gen (15 to 17 per cent.). Coal contains from 1 to 3 
per cent, of nitrogen. The sulfur varies between 
wider limits. The sulfur can be in union with the 
carbon and the hydrogen, and is then invisible; or 
combined with iron as yellow pyrite, and is then 
readily visible. 

Coal always leaves a residue after the carbon 
and hydrogen have been volatilized by oxidation 
into CO 2 and IPO. The residue is called ashes,' 
because wood leaves ashes. The two kinds of ashes 
are very unlike. From coal ashes water does not 
extract potash, nor any other body ; coal ashes are 
quite insoluble ; no alkaline reaction whatever. 
Neither HC1 nor HNO 3 nor H 2 S0 4 dissolve it, only 
HF. The ashes in fact contain chiefly the oxyds 
of silicon and aluminum SiO 2 , A1 2 3 , and Fe 2 3 
when the ashes have a brown color. The clinker- 
ing or semi-fusion of the coal ashes is due to Fe 2 3 
which acts as a flux upon the other oxyds ; white 
coal ashes never show clinkering. The following 
analysis, made by me lately, gives the ultimate 
composition of a soft coal from Kansas. Carbon = 
75.35, hydrogen = 5.50, oxygen and nitrogen = 
10.10, sulfur -1.54, SiO 2 ==4.35, A1 2 3 = 2.70 
(being together ashes equal 7.05, snow white) mois- 
ture =0.45. 

Notice the total absence of iron oxyd, whence it 
follows that the sulfur must be combined with the 
carbon and hydrogen. This coal belongs to the 
semi-bituminous variety verging upon cannel ; for 



312 CHEMISTRY SIMPLIFIED. 

the residue merely adheres slightly after having 
been exposed to a high yellow heat, and like cannel 
it has a dull, black color ; powder brown. 

The proximate composition of the different varieties 
is but imperfectly known, or rather guessed at. I 
mean by proximate composition the molecular 
structure the manner of combination of the ele- 
ments. You can do no better than to imagine the 
coal to be an intimate mixture of solid hydrocar- 
bons, oxy-hydrocarbons, sulfo-hydrocarbons, nitro- 
hydrocarbons, amorphous carbon, and mineral par- 
ticles constituting the ash. The different varieties 
of hard and soft coal arise from the preponderance 
of one or more of the above groups of molecules. 
Reasons for this hypothesis are : (1) The crystalline 
structure of the coal, revealed in thin translucent 
plates or sections under the microscope ; (2) The 
actions of solvents upon the coal, such as ether, 
benzole, carbon disulfid, potassium or sodium hy- 
droxyds. 

Origin of coals. That cellulose is the original 
material there is no reason to doubt ; all hypotheses 
or theories start with this base. Generally, how- 
ever, geologists assume that the material for the 
coal beds consists in the successive growth of tropi- 
cal forests one on top of the other. My own theory 
differs from this. The chief reasons are that in 
many places we find trees standing upright in the 
coal beds, reaching even into the sandstone or slate 
strata lying over the coal bed as shown in Fig. 92. 
Here a section is reproduced from an English coal 



MINERAL COAL AND ITS CHEMISTRY. 



313 



mine, a is limestone, b is fire-clay (under clay), cc 
the lower and upper benches of a coal seam, e black 
coal slate, / sandstone, g brown slate, tit are fossil 
trees, whose bark is also coal, but whose interior is 
sandstone, because these trees belonged to the class 
of giant reeds, calamites lepidodendron, sigillaria, 
etc., and therefore contained a pithy interior and a 
very strong fibrous rind, very resisting to chemical 
change, d is a band of slate separating the coal- 




bed into the two benches. The strata a and b were 
in horizontal position during the coal-forming times 
and the conditions of level equal to that of very 
shallow basins very near the sea level ; that is, the 
general conditions were those of a tropical swamp 
as we find them in our time along the Amazon 
River in South America. At first these conditions 
were favorable to the growth of the great ferns and 
the gigantic reeds. Later on, the land sinking very 
slowly, the swamp became too wet for this vegeta- 
tion and in its stead algae the lowest type of plant 
life which you find always in the shallow pools of 



314 CHEMISTRY SIMPLIFIED. 

our present swamp woods, the green and brown 
threads began to flourish abundantly, luxuriantly. 
An alga is a plant consisting of one cell or of an 
aggregate of cells, of which however each cell re- 
mains a life unit. Each cell has a thin wall of cel- 
lulose enclosing a liquid interior in which there is 
a floating patch of protoplasm, the cell-nucleus or 
cell-kernel. While these generations of very rapidly 
growing cells died and accumulated on the bottom 
of the pool, or rather upon their dead predecessors, 
and being under water could not rot, the rivers or 
creeks emptying from higher ground into the 
swamps brought the fine sand and clay which 
settles very slowly, as you well know from the rivers 
remaining turbid long after a freshet. In time this 
material the silt settles and mixes with the vege- 
table ooze, and there we .have an explanation of the 
intimate admixture of the ash particles with the 
coal, and also an explanation of the strong varia- 
tion of the ash percentage in the different parts of 
a coal bed. Whenever a slate band occurs in the 
coal, according to this theory, we presume that an 
unusual freshet carried the silt faster into the basin 
than the algae could accumulate, in fact the muddi- 
ness interfering with rapid growth. The silt also 
settled into the hollow trunks of the trees, thus pre- 
serving them against collapse by external pressure. 
My theory of the algae accounts also for the high 
percentage of nitrogen, which we find in the coal, 
because the relative percentage of protoplasm to 
cellulose or of nitrogenous substance, is larger in 



MINERAL COAL AND ITS CHEMISTRY. 315 

the algae than in the complex cell-structures of trees. 
During the accumulation of the ooze a decomposi- 
tion of the dead algae cells began to set in, alike to 
that which we now-a-days observe in the peat bogs, 
by which the percentage of carbon in the residue 
steadily increases, while hydrogen ^and oxygen, 
notably the latter, decrease : CO 2 forming and CH 4 
and IPO. At last, the ground sinking more 
rapidly, the influx of silt increases and the vegeta- 
tion stops, the sea finally encroaches upon the 
swamp and the materials for sandstone or limestone 
are brought in. They cause a steadily increasing 
pressure, under the influence of which internal heat 
arises, which cannot dissipate as the rocks are very 
bad conductors of heat. Thus the plant material 
comes gradually under the conditions of the experi- 
ment upon cellulose, described a few pages back. 
Wherever the pressure was greatest the change 
towards carbon was greatest. Thus we find in East- 
ern Pennsylvania only anthracite with 90-94 per 
cent, of carbon, because the side pressure upon the 
strata was so great, that the latter became greatly 
bent and even doubled upon themselves as shown 
in Fig. 93, whilst in the Western States the strata 
remained in their original horizontal position, as 
seen in Fig. 94, except in Colorado, and hence we 
find anthracite in the latter state. The dotted lines 
in Fig. 93 denote that part of the coal bed which 
has been removed and lost by surface destruction 
and the forming of the present topographical out- 
lines. All the details of the structure of the coal 



316 CHEMISTRY SIMPLIFIED. 

measures belong to geology ; only sufficient had to 





FIG. 94. 



V 



be introduced here to make the chemical theory 
intelligible. 

DISTILLATION OF COAL COKING PROCESS. 

By distillation of cellulose or wood we ob- 
tained charcoal, tar, pyroligneous acid, CO, CO 2 , 
CH 4 , H ; and since coal is derived from cellulose 



MINERAL COAL AND ITS CHEMISTRY. 317 

we may and should expect similar, if not identical, 
products. In order to test this proposition we rig 
up the set of apparatus, Fig. 76, page 275. The 
tube Twe charge with the coarsely-powdered coal, 
so that when the tube lies in horizontal position 
and has been tapped upon, the coal only fills one- 
half of the tube. Why ? Because at red heat the 
bituminous and semi-bituminous coals swell up, 
thus clogging the tube to the escaping gas, which 
latter, with increasing pressure, will invariably 
break the tube. We Mart heating at the front by 
using the diaphragm or shield S. First we note a 
heavy yellow vapor, from this condenses a brown 
liquid in the receiver 3, and the bell B fills itself 
with gas. The first portion of gas we allow to 
escape, because it is mixed with the air in T and 3. 
Anthracite gives no vapor, no condensing tar, only 
a relatively small volume of gas ; because anthra- 
cite has already undergone the distillation under 
the influence of great pressure. When, at bright 
red heat, the evolution of gas becomes very slow, or 
stops altogether, we disconnect the receiver 3 from 
T and B from 3. We pull the tube T from the 
furnace, let it become cool, and then break the tube. 
We find the residue more or less bright, porous, dark 
or light grey in color. With large pores the stuff 
is more or less friable, with small pores it becomes 
hard and tough. For bituminous and semi-bitum- 
inous coals the weight of the residue is from 50 to 
65 per cent, of the original weight of the coal. 
The technical name of this residue is coke, which 



318 CHEMISTRY SIMPLIFIED. 

word is derived from to cook, and may have been 
merely a provincial substitute for cake. When 
brought up to a red heat in a current of air the 
coke burns without making a visible flame, although 
it still contains a remnant of hydrogen and oxygen, 
for the complete change of coal to carbon depends 
upon the temperature and time. At a white heat 
(in fire-clay crucible), the last remnant of hydrogen 
can be eliminated. The ordinary coke is, therefore, 
a mixture of the ashes with carbon (amorphous 
and also graphitic), and more or less hydrocarbon. 

Coke is required as fuel in blast furnace work, es- 
pecially in the high-stack-furnaces for the reduction 
of iron ores. Why ? Because if coal were used, the 
latter would convert itself into coke in the furnace, 
would cause a loss of heat energy (elimination and 
decomposition of the hydrocarbons and oxy-hydro- 
carbons requires heat addition from outside sources), 
and the coke thus forming would cement the pieces 
of ore and flux into a solid cake, through which the 
large quantities of nitrogen and carbon monoxyd 
are blown in at the bottom of the furnace could not 
pass the furnace would clog or choke and event- 
ually extinguish itself. 

For this need of the blast furnaces, immense quan- 
tities of coal are converted into coke. The appara- 
tus for making coke is known as coke oven, not kiln 
or furnace, but oven. Why ? Because the first coke 
was made in Dutch bake-ovens. The so-called bee- 
hive coke oven of the present time is merely a slightly 
modified bake-oven. In this oven all the gas and 



MINERAL COAL AND ITS CHEMISTRY. 319 

the tar are wasted. In the scientifically constructed 
ovens, the gas and tar are utilized. Different ovens 
have been constructed in Europe in great profusion. 
Those mostly used now are the Solvay oven, and 
the Hoffman oven ; they have also been intro- 
duced into the United States. The detail of coke- 
making belongs to metallurgy. We ttfrn now to the 
contents of the receiver (3). As in the distillation 
of wood we find two liquids, one oily the so-called 
coal tar, one watery of light-brown color. This 
watery liquid smells of ammonia, and turns red litmus 
paper blue. Thus it is the reverse of pyroligneous 
acid from wood distillation. Addition of acid to 
the ammonia water produces effervescence : CO 2 , 
H 2 S are given off, hence the water contains am- 
monium carbonate and ammonium sulfid. The 
occurrence of the ammonia proves the presence of 
nitrogen in the coal. The absence of the acetic acid 
may be explained from the smaller percentage of 
oxygen in the coal and from the higher temperature 
needed to break up the coal, a temperature at which 
C 2 H 3 2 .H breaks up into CH 4 + CO 2 . The princi- 
pal market for ammonia being that as fertilizer, the 
cheapest way of extracting the former is to convert 
it into sulfate. The water is neutralized with 
H 2 S0 4 and the solution evaporated by means 
of the waste heat from the ovens. The result is 
dark-brown, crude sulfate. This is redissolved in 
the requisite quantity of boiling water, filtered 
through a bed of charcoal to remove the tar which 
separates during evaporation, and the liquid is run 



320 CHEMISTRY SIMPLIFIED. 

into flat basins, where the sulfate crystallizes on 
cooling. This second product is still yellowish, but 
good enough for the market. 

The coal tar, the oily portion of the condensed 
vapors, is composed essentially like the wood-tar. 
But certain valuable hydrocarbons are contained in 
the coal tar in larger percentage. These hydrocar- 
bons are: benzol (C 6 H 6 ), toluol (C 7 H 8 ), phenol 
(C 6 H 5 (OH)), naphthaline (C 10 H 8 ), anthracene 
(C 14 H 10 ). When the tar is subjected to distillation, 
light oils pass over first up to a temperature of 180 
C. Benzol, toluol, phenol are contained in this 
portion ; at a higher temperature oil passes over 
which solidifies on cooling. The cooled mass can 
be recrystallized from an alcohol solution, or it may 
be purified by sublimation. In this purified state 
it forms large thin crystals in form of plates with 
the luster of mother of pearl and a strong peculiar 
odor. This is the napthaline of trade and is largely 
used to protect woolen and fur goods against insects : 
moth balls. Only the oil which passes over between 
80 and 100 C. is used for the manufacture of ben- 
zol. Between 100 and 130 C. toluol and phenol 
with some benzol pass over. Pure benzol is a color- 
less very mobile liquid ; boils at 82 C. and crystal- 
lizes at C. Specific gravity = 0.85. 

Nitrobenzol, C G H 5 .NO' 2 . Is obtained by treating 
the benzol with a mixture of cone. H 2 S0 4 and 
very cone, or fuming HNO 3 in cast-iron cylinders, 
which can be cooled by running water, because 
the reaction is very energetic ; 1 hydrogen of the 
C 6 H 6 is removed as water and nitrobenzol results. 



MINERAL COAL AND ITS CHEMISTRY. 321 

C 6 H 6 + HNO 3 = C 6 H 5 N0 2 + H 2 0. 
Nitrobenzol is a yellowish heavy oil which boils at 
205 C. ; and has a pleasant odor resembling that of 
the oil made from bitter almonds. If an excess of 
HNO 3 is used the dinitrobenzol C 6 H 4 (N0 2 ) 2 results. 
Anilin,C 6 H 7 N. A small quantity of this highly 
interesting substance is already contained in the tar. 
But from nitrobenzol it can be obtained in any de- 
sired quantity. Anilin forms a colorless liquid, 
diffracts light strongly, has a'peculiar odor and burn- 
ing taste. The oil bqils at 182 C. and solidifica- 
tion sets in at 8 C. Specific gravity == 1.02. Is 
very slightly soluble in cold water, more so in boil- 
ing water, but quite soluble in alcohol, ether, carbon 
disulfid, and coal oil. It burns with a very smoky 
flame. Is very poisonous. Chemically anilin may 
be considered as ammonia in which 1 H has been 
replaced by the hydrocarbon radical phenyl thus 

HI (CH')-| 

H >N = ammonia. H >N = anilin. 

HJ H j 

Like ammonia it unites with HC1 and other acids 
and forms salts : C 6 H 5 .H.HNHC1 = anilin chlorid. 
These salts are mostly easily soluble in alcohol and 
crystallize readily. Anilin is a fine example of a 
complex base. 

Methylanilin is another base, arising from a sec- 
ond hydrogen being replaced by methyl, thus : 

C 6 H 5 .H.H.N + CH 3 I + heat = (C 6 H 5 )(CH 3 ).H.N 

+ HL 
21 



322 CHEMISTRY SIMPLIFIED. 

This body, known as " Mauve de Paris," colors 
silk and wool a fine violet color. 

Rosanilin, fuchsin. This was the first splendid 
dye-stuff prepared from coal-tar through the way of 
anilin, by means of oxydation ; usually As 2 5 is 
used as the oxydizing agent. 100 parts of anilin 
oil are poured slowly into 150 parts of a water-solu- 
tion holding 75 per cent. As 2 5 in an iron vessel 
with stirring apparatus. The temperature is raised 
and kept for five hours at 182 C. Water and un- 
changed anilin dissolve during this period. The 
semi-fluid residue has a bronze color, and from it 
the dye-stuff is extracted by boiling water, filtered, 
under pressure, through felt. Solution contains the 
rosanilin as arseniate and the As 2 3 which is formed 
during the process of oxydation. By saturating 
the solution with NaCl (equal in weight to the resi- 
due), the hydrochlorid of rosanilin forms and 
Na 2 HAs0 4 . Red crystals fall out, in measure, as 
the liquid cools. By recrystallizing this first pro- 
duct a. higher grade is obtained. The red crystals, 
being the chlorid of rosanilin, are known in the 
dye-works as fuchsin. By acting on the water solu- 
tion with NaOH, the base rosanilin is obtained as a 
white precipitate, which becomes intensely red in 
contact with any acid. The composition of rosanilin 
isC 20 H 19 N 3 . It forms thus: 



C 7 H 7 
2 H 
H 



C 6 H 5 
N + H 
H 



C 6 H 



N+30 = 



C 7 H 7 



N 3 +3H 2 0. 



The 30 are furnished by As 2 5 or any other oxy- 



MINERAL COAL AND ITS CHEMISTRY. 

dizing agent. But we see that another body is here 
contained, the toluidin, besides the anilin. Remem- 
bering, however, that the raw oil contains benzol 
and toluol, the phenomenon is explained. 

The crystals of fuchsin are green-golden in ap- 
pearance, like a brilliant metal. They dissolve in 
water with intense red color. If well cleansed silk 
or wool be hung in such a solution, the liquid 
becomes colorless by degrees, all the coloring fuchsin 
will have transferred itself to the fibre, producing 
thereon the beautiful red tints according to the 
quantity transferred. The color fixes itself, does 
not require a mordant or fixing agent. 

Mauvanilin, (CH 5 )(C 6 H 5 )(C 7 H 7 )N*.HCl gives an 
orange-yellow dye. A great many other beautiful 
dye-stuffs have been produced by further substitu- 
tion of hydrogen in the base by other radicals, as 
anilin, toluidin, or simply methyl, ethyl, and others. 
My main purpose in devoting so much, space to this 
subject was to impress upon you the possibilities 
lying hidden in such a material as the ugly, bad- 
smelling coal-tar, and the great fortunes which have 
been made by utilizing it in the right way. 



CHAPTER XVII. 

THE GASES FROM THE DISTILLATION OF COAL- 
MANUFACTURE OF ILLUMINATING 
GAS AND GAS COKE. 

The contents of the bell jar are at first cloudy 
from exceedingly small particles of semiliquid bodies, 
which will condense after a time, forming a thin 
layer of tar upon the retaining water surface. If 
now the gases be subjected to the analysis by ab- 
sorption which has been given in detail under cel- 
lulose or wood, it will be found that the composi- 
tion by quality does not differ much ; the relative 
quantities differ considerably, and even very much 
when the gas from the early distillation is compared 
with that which is given off at the end of the opera- 
tion. We find H, CH 4 , CO, CO 2 , non luminous : 
C 2 H 4 , C 3 H 6 , C 4 H 8 and C 2 H 2 , (acetylene) as lumi- 
nous gases. NH 3 , SH 2 , CS 2 , CN as impurities. 

Of the luminous or light-producing hydrocarbons 
ethylene (C 2 H 4 ) olefiant gas (oil-making gas) is the 
most important; of propylene (C 3 H ) there is least ; 
of butylene C 4 H 8 there is usually from J to J as 
much as of ethylene. These hydrocarbons combine 
with chlorine, bromine or iodine, thus : 

C 2 H 4 + 2C1 =C 2 H 4 C1 2 , ethylene chloride oil-like 
liquid (hence the name olefiant or oil-making.) 
Spec. Gr. = 1.174. 

(324) 



GASES FROM THE DISTILLATION OF COAL. 325 

At red heat ethylene breaks up, thus : 
C 2 H 4 + red heat = C + CH 4 , amorphous carbon 
+ marsh gas. 

It is this action which we call dissociation, that 
a'ccounts for the smoking of a gas flame. If oxygen 
is present both C and CH 4 are oxydized to 2C0 2 + 
2H 2 0. Bromine acts like chlorine upon ethylene: 
C 2 H 4 + 2Br = C 2 H 4 Br 2 an oily liquid as the pre- 
ceding one. Propylene and butylene are acted upon 
similarly: C 3 H 6 + 2C1 = C 3 H 6 C1 2 ; C 4 H 8 + 2C1 = 
C 4 H 8 C1 2 , propylene chlorid, butylene chlorid. 
Hence it follows that we can remove these three 
gases from a mixture of gases by shaking the mix- 
ture with bromine water in a suitable gas pipette. 
The higher we find their percentage in a given gas 
the more we are sure of a bright light, provided 
that the burner be suitably constructed. 

PLAN FOR GAS WORKS. 

Figs. 95 and 95a give the essential pieces of ap- 
paratus for the production of illuminating gas by dis- 
tillation of coal, in ground plan and length elevation. 
R, R',R 2 represent a fire-brick retort and ovens for 
heating them to a yellow heat. H is a sheet-iron pipe 
18" to 24" in diameter and known as the " hydraulic 
main." The elevation shows how the retort con- 
nects by a goose-neck pipe with this main and also 
that the pipe dips under the water level of the main, 
thus producing a light pressure upon the gas in the 
retort. Most of the condensible constituents of the 
gas become liquid in contact with the liquid in the 



FIG. 95. 




(326) 




(827) 



328 CHEMISTRY SIMPLIFIED. 

pipes. At N there is provided an overflow which 
drains into a vertical tank or cistern ; thus the level 
remains always the same in the main. Steam, tar, 
ammonium salts are condensed largely. A pipe C 
leads from top of main to the purifying towers 
S,S',S 2 which are technically known as scrubbers. 
S,S f are wet scrubbers, because the gas must pass the 
extensive surface of the horizontal trays over which 
flows a film of cold water. All the ammonium 
compounds and all the tar are removed from the 
gas in these wet scrubbers, but the gas still contains 
a notable quantity of hydrogen sulfid. The latter is 
taken care of in S 2 which is a dry scrubber, for 
here the trays are covered each with a layer of 
Laming' s mass, to wit : a mixture of Ca(HO) 2 with 
FeSO 4 + 7H 2 (copperas). Ca(HO) 2 + FeSO 4 - 
CaSO 4 -f Fe(HO) 2 ; it is the latter, ferrous hydroxyd, 
which is the active agent. At first Ca(HO) 2 (dry 
slaked lime) was used alone. Ca(HO) 2 + EPS = 
CaS + 2H 2 0. But the action is slow. When the 
book-backs in the public libraries of London and 
other cities began to crumble away, the cause was 
traced to the gas flames and more specially to the 
sulfuric oxyd produced by them, i. e., by the burn- 
ing of H 2 S to SO 3 . Then Laming invented the 
mixture and thus checked the evil, without knock- 
ing it out altogether. The carbon disulfid CS 2 has, 
so far, resisted all attempts at absorption in the 
scrubbers. The dry scrubbers must be provided in 
duplicate or triplicate, because they need frequent 
renewing of the Laming mixture, which becomes 



GASES FROM THE DISTILLATION OF COAL. 329 

foul as the men say. The gas is now ready to flow 
through the pipe C f " into the holder G. The 
holder is a sheet-iron tank of circular or cylindrical 
shape. It is closed at the upper end and dips with 
the open lower end into water of the walled and 
cemented cistern C. The tank G is held in place 
by 6 or more guide rolls, and is counterbalanced 
by the 6 weights W, W, etc. These consist of cast 
iron disks, superposed, so that the bell may be made 
to press upon the gas at any pressure, by adding or 
removing a disk, from each or to each, of the 6 
weights. By adding disks the bell may take the 
function of a suction pump thus causing the gas to 
overcome the friction of scrubbers, during the 
progress of the distillation. The elevation explains 
the entrance of the gas at in and the outflow at out 
if the main valve V' is open. This valve is always 
accessible through the pit P. The dimensions of 
the plant follow from the rate of consumption of the 
gas. As one 15 candle-power burner consumes 5 
cubic feet of gas per hour, and as the burners are 
needed on the darkest day for 8 hours, and as each 
family uses on the average 4 burners, we get 160 
cubic feet per family per day. 1000 families require 
160,000 cubic feet + 10 per cent, for street lighting, 
total 176,000 cubic feet, hence 18 tons of coal will 
be required per day giving roughly 9 tons of coke. 
A bell 30 feet in diameter and 20 feet high will 
hold 16,000 cubic feet. Ten such would be required 
to store the 160,000 cubic feet. However the bell 
serves more as a regulator than as a storage. The 



330 CHEMISTRY SIMPLIFIED. 

retorts are kept going all through the hours of 
largest consumption. One holder is sufficient for 
each 1000 families. Holders of 100 feet diameter 
and 25 feet high have been built in large cities. 
The retorts are made of fire-brick material and have 
a ^^ section. They are 5 to 6 feet long, 18 to 24 in. 
wide (inside), 12 to 15 inches high. Thickness of 
bottom 3 to 4 inches, of sides and top 2J to 3 inches. 
The average daily capacity per retort is 5000 cu. 
feet ; hence 32 retorts will be required for 160,000 
cu. ft. daily production. The retorts are best 
arranged in batteries of 7 each with one common 
fire-place. 

WATER-GAS. 

(a) Water-Gas. H 2 + C=H 2 -f-COat yellow 
or white heat. The mixture of hydrogen and car- 
bon, monoxyd burns with colorless flame, hence the 
gas must be made luminous by the addition of 
gasoline or hydrocarbons of the olefine series. 
Prof. Lowe of Norristown, Pa., introduced the ap- 
plication of this reaction into the gas industry about 
1873. It displaces' the distillation process, but has 
not been introduced in many gas works until more 
recently in a modified form. 

The action H 2 + C=CO + H 2 is endothermic, 
heat-consuming. 

The action C + 20 = CO 2 is exothermic, heat- 
producing. 

Hence the process of preparing water-gas is 
necessarily a double one, Let 1, 2, Fig. 96, be two 



GASES FROM THE DISTILLATION OF COAL. 331 

fire-brick cylinders held each in a sheet-steel mantle. 
Let these cylinders stand upon iron pillars, 10, 10. 
10, which will enable a dropping of the hinged 
bottoms, 3, 8, and thus an emptying of the cylinders 
of ashes and klinkers. Let the cylinders be filled 
with pieces of coke or charcoal. At 4, 4 we have 
charging hoppers. At 5, 5 air-pipes enter the 
cylinder, and at 6, 6, steam-pipes. At 7, 7 small 




pipes can introduce coal-tar. The gas passes at <?, 8 
into the common pipe 9. Before charging the coke, 
small wood and shavings are put into the cylinders 
to start the fire with in one cylinder first. Then 
compressed air is allowed to enter the through pipe 
5, coke is charged until it reaches just below the gas 
outlet 8, and the valve in the hopper 4, is left open. 
Under these conditions, a gas mixture passes out from 
the hopper, which is composed of nitrogen, chiefly 



332 ' CHEMISTRY SIMPLIFIED. 

(60 per cent, to 70 per cent), carbon dioxide and 
carbon monoxyd (N + CO 2 + CO). The sum of 
N + CO 2 being at the least 75 per cent., it follows 
that this gas is only a low-grade heat-producer, and 
is therefore allowed to escape through the hopper. 
When the top layer of coke has come to bright red 
heat, the lower layers will be at white heat. The 
hopper valve is now closed, and the valve at 8 
opened. The air valve in 5 is closed, and the 
steain valve in 6 opened. As the steam impinges 
upon the white-hot coke, it breaks up into H 2 + CO. 
If the valve in the tar pipe T be now opened 
properly, the tar will fall upon the bright red coke 
and be dissociated, i. c., the higher molecules of 
C n H n , C n H 2n and C n H 2n + 2 will be broken up into 
the lower members of the series, into carbon and 
into marsh-gas. Read again what is said about this 
under tar and the distillation of coal. All these 
hydrocarbons will mix with the main mass of 
hydrogen plus carbon monoxyd, will pass through 
pipe 9 into the gas holder, or directly to the burners, 
and yield a fine light, or if more air be allowed to 
mix with the gas in the burner, a very intense heat, 
and a non-luminous flame. All this while the 
white heat of the coke drops down steadily to a red 
heat and H 2 can be no longer decomposed. In 
common language we say that the steam quenches 
the fire, i. e., extinguishes it. But the second 
cylinder has been brought up to white heat during 
the time. We shut off the first cylinder from pipe 
9 } open the valve and the steam valve, repeating 



GASES FROM THE DISTILLATION OF COAL. 333 

all the operations as before, while the first cylinder 
is again blown to white heat exchanging the 
steam for air. Thus by means of the two cylinders 
a perfectly steady stream of water-gas is produced. 
A battery of three cylinders is more advantageous 
still, for then we can throw out one after another 
of the cylinders for the purpose of removing the 
ashes and klinkers without danger of explosion. 



FUEL GAS. 



Under this name goes a mixture of gases of in- 
ferior grade to the water-gas ; cheaper correspond- 
ingly, and much in use, at this time, in metallurgi- 
cal works and also for the feeding of gas-engines. 




Chemistry. Steam and air are blown into the 
coke simultaneously ; the air and the steam periods 
of the water-gas process are thrown into one period. 
One cylinder only is required for the same volume 
of gas per minute. Let Fig. 97 represent the sec- 



334 



CHEMISTRY SIMPLIFIED. 



tion plan of the cylinder in the level of the steam 
pipe 6, Fig. 96; let S, S l} S 2 be the three steam 
pipes and i, i, i the parabolic injectors (system of 
Koerting). Then there will be sucked up by the 
steam jets a volume of air depending upon the 
velocity of the steam (pressure) and upon the capa- 
city of the injector. The pressure of the steam must 
be adjusted to the capacity of the injector so that the 
exothermic product CO 2 -+- N 4 is larger by about 
i than the endothermic product C + H 2 0(CO + H 2 ). 
The i over energy is consumed by loss of heat 
through conduction, radiation and fusion of the 
ashes. The latter, the fusion of the ashes, can not 
be obtained unless a proper amount of CaO be 
charged with the coal or coke and the percentage of 

FIG. 98. 




each as well as the composition be known. A lip 
or outflow must be provided for the slag as shown 
in Fig. 98, where 1 is the slanting bottom, 2 the 
dam of the forehearth, 3 a hollow iron beam, 
through which water circulates to keep open the out- 
flow and prevent the eating away of the firebrick ; 
4. is the inner level of the liquid slag ; 5 is its outer 
level and when more slag comes it will run over the 



GASES FROM THE DISTILLATION OF COAL. 335 

dam ; 6 is the twyer or opening for the injector ; 7 is 
the foundation. If raw soft coal is to be used in this 
fuel-gas proposition, the cylinder must be provided 
with a rotating breaker, to prevent the forming of 
cakes and lumps, which always make poor gas. 

PETROLEUM, ROCK-OIL, MINERAL OIL. 

The term coal-oil is most used in the United 
States. It is nut a good name because implying a 
relationship between coal and this oil. Such a re- 
lationship has not been proven in any instance. 
All the Pennsylvania, Ohio, West Virginia, Indi- 
ana oil comes from rocks which lie under the coal 
measures, very much older in order of formation. 
Rock-oil is a perfectly appropriate term. In regard 
to the origin of the oil in these rocks, the most plaus- 
ible opinion is that of Engler who ascribes the oil 
to enormous numbers of dead fish within the sand, 
which now forms the oil-carrying strata. Engler 
obtained oils very similar to coal-oil by subjecting 
fish to great pressure at temperatures not much 
above the boiling-point of water. 

Finding of the oil. Along Oil Creek, Pa., the oil 
was found but 50 feet under the surface, but for the 
most part the oil strata are buried deeply. The 
gushing or flowing of the oil from a fresh hole is 
due to the accumulated pressure of marsh gas. As 
this pressure becomes released the automatic flowing 
ceases, and pumping becomes necessary. 

Physical properties of the oil. Most oils are col- 
ored ; they appear red or brown-red in transmitted 



336 CHEMISTRY SIMPLIFIED. 

light and opalescent green in reflected light. This 
double-color or dichroism is owing to the presence in 
the oil of one constituent which has received the 
proper name : fluorescin. The odor is very strong 
and characteristic. Sometimes the crude oil is quite 
mobile and sometimes it is thickish, viscous. So 
also varies the specific gravity from 0.75-0.95. 
None has yet been found heavier than water. The 
crude oil is usually quite inflammable. 

Chemical properties. In general it will hold true 
to say : Petroleum is a complex liquid. The consti- 
tuting members of the complex are hydrocarbons 
of the marsh gas or paraffin series (C n H 2n+2 ). The 
individual members of the series can be separated 
by fractional distillation many times repeated (see 
under wood-tar and coal-tar). The members from 
C 4 H 10 to C 16 H 34 have actually been prepared by 
several chemists. The density of the liquid and its 
boiling-point are the mean of those constants pro- 
portionately to the percentages of the constituting 
hydrocarbons. The heat-value of coal-oil is very 
high, much higher than that of vegetable and 
animal fats, because oxygen is absent. Some crude 
oils, however, contain sulfur compounds. Coal-oil 
cannot be saponified by NaHO or KHO, and by 
this negative property we distinguish the mineral 
oil from vegetable or animal oil. (See further on.) 

Refining of crude oil. The crude oil is stirred 
together with concentrated sulfuric acid. By this 
treatment the objectionable sulfur compounds are 
converted into a solid, resinous body which settles 



GASES FROM THE DISTILLATION OF COAL. 337 

with the acid, and the cleansed oil is drawn off. The 
latter is then subjected to the action of steam heat 
in large iron tank-boilers, and later on to direct fire. 
Thus are obtained the conventional fractions : 1. 
Petroleum ether, a colorless, very mobile oil of pleas- 
ant odor and intoxicating effect, passes over up to 
70 C. This oil is much used as a solvent for fats 
and other bodies. 2. Gasoline distills between 70 
C. and 90 C. 3. Benzine distills over between 90 
C. and 150 C. After this is collected 4. Kerosene 
between 150 C. and 300 C. This portion is most 
valued for burning in lamps, because its flash-point 
is high and it is therefore safe. 5. Lubricating oil 
distills between 300 C. and 400 C. 6. Vaseline 
distills next and condenses as a semi-solid in the re- 
ceiver. 7. Beyond this comes off considerable 
paraffin, a perfect solid (see under tar); a black, 
spongy residuum remains in the still. 

Determining the flash-point of a given coal-oil. 
Pour the oil into a small tin-cup, which stands upon 
a water bath. With one hand hold a thermometer 
into the oil, with the other pass a lighted match 
across the surface of the oil. Note the temperature 
of the oil at which the vapor above the oil catches 
fire. This temperature is known as the flash-point 
and should not be below 60 C. for a safe burning oil. 

NATURAL GAS. 

Any bore-hole which is driven into sedimentary 
rock-formation can be expected to produce gas, pro- 
vided the strata have not been disturbed much from 
22 



338 CHEMISTRY SIMPLIFIED. 

their original horizontal condition. Natural gas has 
been found by many analyses to be composed chiefly 
of marsh-gas (CH 4 ). If it burns with a sooty flame 
then there are some of the higher members of the 
paraffine series present, each as C 2 H 6 , C 3 H 8 . . . 
Sometimes there is free hydrogen present and in rare 
instances CO has been found with the marsh-gas. 



CHAPTER XVIII. 

THE HOMOLOGUES OF CELLULOSES-STARCH, 
DEXTRIN, SUGARS. 

So cunning is the work of nature that extraordi- 
nary changes are constantly brought about in prop- 
erties with apparently tbe same material. The study 
of a wheat grain will illustrate this. Fig. 99 repre- 

FIG. 99. 




sents the section through the axis of the grain in 
magnified dimensions. Beginning from the outside 
there are 3 layers of small, attached cells 1, 2, 3. J, 
2 epicarpium or skin, colorless cells. 3 the endo- 
carpium ; these cells contain a yellow coloring mat- 
ter. 4- the embryo membrane, large cells, contain- 
ing the nitrogenous body gluten, vegetable albumen. 
5 a layer of amorphous substance, grey. 6 the meal- 
kernel made up of large, loose cells, and these cells 
(339) 



340 CHEMISTRY SIMPLIFIED. 

are filled with a multitude of white globules which 
globules constitute what is known as starch. 7 is 
a dark-colored cell, known as the embryo or germ. 

When such a wheat grain is soaked in water or 
kept wrapt in a wet cloth the grain swells and two 
sprouts appear at 8, that is, the vital power lying 
dormant in the protoplasm of the germ cell awakes 
in presence of water. Cell upon cell is shot out- 
wards until two blades of grass appear above the 
earth, which gradually develop into a full plant. 
The material for these cells was drawn from the 
store of starch and albumen, so cunningly provided 
within the reach of the embryonic cell within the 
grain a veritable fodder-sack. 

The starch, amylum. A white, very finely gran- 
ular substance. Under the microscope we see 
spheroidal granules built up from concentric layers. 
Feels soft to the touch. When pure has neither 
taste nor smell. Is insoluble in cold water. Hot 
water swells the granules until they flow together 
into a shapeless, transparent paste, starch-paste. 
The paste dries into a yellowish, hard, horn-like 
body. The paste is slightly soluble in water, giving 
a clear solution upon standing. Starch develops 
in the roots of certain plants, namely, such plants 
which grow from the root just as well as from a 
seed potato, arrow root, sago. The seed grain of 
Indian corn is richer in starch than other seed 
grains. Hence starch is made from either corn or 
potatoes. The corn is ground, while the potatoes are 
cut into a pulp by rotating knives, after a thorough 



THE HOMOLOGUES OP CELLULOSE. 341 

washing, to remove adhering soil particles. The 
pulp becomes milky ; the milky liquid is strained 
off through a very fine hair sieve. The sieve retains 
the cellulose or skin portions, and also the gluten. 
The milky liquid is allowed to stand, when the 
white starch will settle to the bottom and is col- 
lected after drawing off the water. The starch only 
needs drying to be at once a commercial product. 

Chemical properties of starch. (1) The analysis 
(same as for cellulose) leads to the ratio C 6 H 10 6 , 
that is to say, identical with cellulose. Note nature's 
trick to give two very different bodies the same 
composition. Such bodies are named isomeric bod- 
ies. (2) A solution of iodine in alcohol or in water, 
solution of KI colors the starch, first purplish-red, 
and then blue. Heating causes the color to fade, 
but on cooling the color reappears. Very character- 
istic reaction for the identification of starch. (3) 
Starch dissolves in cold, concentrated HNO 3 . The 
addition of water throws out a white precipitate, a 
nitro-body similar to gun-cotton, but non-explosive. 
Boiling very dilute acid (2-3 per cent.) changes the 
starch into dextrin and finally into glucose. The 
word starch (stark = strong in German, because 
starch paste stiffens tissues). 

Dextrin (from dexter = right-handed). A gum- 
like, syrup-like substance, or dry granular. Much 
used in place of gum arabic (postage stamps, envel- 
opes), because cheaper and more reliable. It forms 
from starch, either by heating the dry starch to 210 
C. or by moistening the starch with 2 per cent. 



342 CHEMISTRY SIMPLIFIED. 

HNO 3 solution, and then heating to 110 C. (best 
method), or by boiling starch with 2 per cent. 
H 2 S0 4 solution until the resultant liquid does not 
turn, blue with iodine solution. Dextrin is C 6 H 10 5 , 
the same as starch and cellulose. Another isomeric 
form. It is not soluble in alcohol, but easily soluble 
in water, rotates plane of polarization to right. 

The sugars. These are bodies formed in the sap 
of the cells of certain plants ; in the seeds (grape, 
orange, etc.) ; in the stem (cane, sorghum, sweet 
corn); in the roots (beets, carrots). "All soluble in 
water ; some crystallize, others are syrups ; all pos- 
sess a more or less sweet taste. 

Cane sugar, C 12 H 22 11 , or CH 10 5 + H 2 0. 
Obtained by neutralizing the somewhat acid sap of 
the cane, the beet, the sorghum, the maple, by 
means of chalk (CaCO 3 ), and by evaporating the 
clarified liquid rapidly best in a closed boiling pan 
from which vapors and air are steadily withdrawn 
by an air-pump (vacuum pan). From the thick 
syrup fall small crystals ; can be obtained in large, 
very perfect monoclinic crystals by recrystallization, 
which are drained from mother liquor in centri- 
fugal filters, and are then known as crude sugar 
(90-95 per cent.). The refineries remove the 5 or 
10 per cent, of impurities. Cane sugar is easily 
soluble in cold water, 2 parts of sugar in one of 
water, much more soluble in boiling water, slightly 
soluble in alcohol, not in ether. Melts at 160 
C., and on cooling forms a vitreous, glassy body 
candy. Heated at 200 C. it becomes black 



THE HOMOLOGUES OF CELLULOSE. 343 

sugar or caramel (black, horny). By destructive 
distillation it forms bodies similar to those from 
starch or cellulose. Cane sugar forms genuine com- 
binations with K 2 0, Na 2 0, CaO, BaO, SrO, all sol- 
uble in water. The combination, C^H^O 11 . BaO 
is now much used in the refining process. Concen- 
trated H 2 S0 4 acts energetically on sugar, SO 2 ; 
H.CHO 2 (formic acid) escape, a coaly residue re- 
mains. Boiling HNO 3 -f IPO converts sugar into 
oxalic acid (H 2 .C 2 4 ), water, CO 2 and NO. A sugar 
solution rotates the plane of polarization to the right, 
like dextrin. If a solution of cane sugar be kept 
digesting on the water bath with HC1, or H 2 S0 4 (a 
few per cent.), its right rotation diminishes and 
turns finally into left rotation ; the sugar is inverted. 
Glucose, grape-sugar, C 6 H 12 6 or C 6 JI 10 5 + 
H 2 0. Is largely contained in honey and in all 
fruits and berries. Crystallizes in small scaly forms. 
Less soluble in water than cane sugar (1 glucose 
1J cold water). More soluble in alcohol than cane 
sugar. The crystals contain one molecule of IPO. 
Melts at 70 C. Does not taste as strongly as cane 
sugar. Concentrated H 2 S0 4 does not change glu- 
cose into a coal-like mass ; the glucose combines 
with the acid to form gluco-sulfw*ic acid. Glucose is 
found in the urine of persons who suffer from dia- 
betes. Copper sulfate + glucose -f potassium hydrate 
-f water gives at ordinary temperature red or yellow- 
red cuprous oxyd. Cane sugar gives such a result 
only by continued boiling. This reaction is the 
best to distinguish the two sugars from one another. 



344 CHEMISTRY SIMPLIFIED. 

Large quantities of glucose are manufactured from 
corn-starch (in U. S.) and from potato starch, 
(Europe). 

CeH 1 5 , starch + water + H 2 S0 4 +" boiling 
heat = C 6 !! 1 2 6 , glucose + H 2 S0 4 . 

Mix 600 grs. of starch with 700 c.c. of luke-warm 
water into a milk. Mix 100 c.c. of water with 5 c.c. 
of cone. H 2 S0 4 . Heat the latter to boiling. Let 
the milk flow into the boiling liquid, but not so 
fast as to interrupt the boiling motion. Keep boil- 
ing for 3 hours, replenishing the water lost by 
evaporation. Perfect solution of glucose. Neutra- 
lize acid with chalk while boiling. Filter through 
bone charcoal ; evaporate to thick syrup and let cool. 
In the course of 10 to 12 hours the syrup will change 
to a stiff mass of small crystals of grape-sugar. 
"Glucose is largely used as a substitute for malt in 
the brewing of beer, also as an addition to grape 
juice before fermentation into wine. By heating 
cellulose with dilute H 2 S0 4 under pressure in closed 
boilers, it changes slowly into glucose (saw-dust 
made into sugar). 

Fruit-sugar, syrup, levulose, C G H 12 6 . Gives the 
slimy consistence to honey. Contained in all berries 
and fruits with the glucose. Does not crystallize. 
Rotates plane of polarization to the left. Invert 
sugar (see above) contains this variety of the family. 
It combines with 3 molecules of CaO to a water-in- 
soluble body, while the isomeric cane sugar gives a 
soluble compound with CaO. The so-called molasses 



THE HOMOLOGUES OF CELLULOSE. 345 

or melasse in French, is largely composed of this 
sugar. 

Milk-sugar, lactose, C l 2 H 2 2 O l 1 + H* 0. Obtained 
in hard, colorless, tetragonal crystals, by evapo- 
rating the liquid obtained by straining curdled 
milk. Is only soluble in 6J parts of cold water. 
Agreeable sweet taste, but not as str6ng as the iso- 
meric cane sugar. Does not melt, but loses the 
water of crystallization at 130 C. 

Gum arabic, arabin, C 12 # 20 10 + H* 0. Con- 
tained in the sap of many plants. It flows from the 
bark and is found adhering in gum drops to the 
bark of the stem or the twigs. Specially plentiful 
in the sap of the acacia trees. Forms with little 
water a thickish, sticky solution. Not soluble in 
alcohol. Does not reduce CuO to Cu 2 as does 
dextrin. Furnishes about 3 per cent, of ashes. 



CHAPTER XIX.' 

ALCOHOL, SPIRITS OF WINE, ETHYLHYDROXYD, 
C 2 H 5 (HO). 

THIS important substance is a derivative of the 
sugars, and especially of glucose grape-sugar. The 
grape-juice is essentially a dilute solution of glucose, 
has a pleasantly sweet taste. When this solution 
remains standing, uncovered, in a warm place (20 
C. to 30 C.), it soon becomes turbid, and gas 
bubbles arise from the liquid more and more abund- 
antly until the liquid begins to froth. As gradually 
as this action has increased it decreases, leaving a 
clear liquid, upon which rests a reddish or brown- 
ish scum, while a similar material has gone to the 
bottom. The liquid has now assumed a sour taste, 
but very agreeable, and when taken in large quan- 
tity produces stupefaction (drunkenness) ; the liquid 
is then known by the name of wine (Latin = vinum). 

Arab experimenters were first in trying to get at 
the understanding of this remarkable action. They 
succeeded, by distillation, in separating the active 
principle of wine in form of a colorless liquid, very 
mobile, and of agreeable odor but burning taste. 
They found that this liquid will burn with a bright 
and very hot flame. The name al-Kohol, the breath 
spirit (from spirare, to breath) was given to this re- 
(346) 



ALCOHOL, SPIRITS OF WINE, ETHYLHYDROXYD. 347 

markable liquid. The Latin translator of the 
Arabic treatise translated al-Kohol into spiritus vini, 
French, esprit de vin ; German, weingeist (the spirit 
or soul of the wine). However, in recent years the 
chemists of all nations use the word alcohol exclu- 
sively. 

The process described above, by which a solution 
of sugar converts itself into a solution of alcohol, is 
now everywhere known as fermentation, the Germans 
alone use an indigenous word gaehrung. But simi- 
lar processes are known to yield other products than 
alcohol ; hence, to be clearly understood, we say 
alcoholic fermentation. The chemical process of this 
fermentation is of the simplest. 

C 6 H 12 6 , glucose + water+ferment = 2C 2 H 5 (HO), 
alcohol + 2C0 2 . 

The gas bubbles forming in the process are CO 2 . 
The ferment or yeast is found in the matter, which 
causes the turbidity of the fermenting liquid, and 
which either rises to form the scum or sinks to form 
the sediment. This matter is biological ; it is alive. 
Under sufficient magnifying power the scum differ- 
entiates itself into cells, single or in clusters. The 
cells have an envelope of cellulose, and are filled 
with a clear liquid. The liquid contains protoplasm, 
which can be separated as white Hocculae. The 
white substance dries into a horny body, the analysis 
of which gives C = 55 ; H = 7.5 ; X = 14 ; + S = 
23.4. In this body rests the life-potency of the cell. 
The cells multiply by " budding," as shown in Fig. 



348 CHEMISTRY SIMPLIFIED. 

100. A yeast cake is merely a multitude of such 
cells with some potato starch. Botanists classify 
these yeast cells as the lowest form of the order 
fungi. The specific name is saccharomycetes cerevisise. 
Because such cells are in the air with other minute 

FIG. 100. 

O 
CD 



dust, the fruit juices begin to ferment, apparently 
by themselves, but if filter paper be tied over the 
vessel, no fermentation takes place. The addition 
of yeast merely accelerates the process. 

The manufacture of ethyl-alcohol. It sometimes 
pays to distill wine (in France), but only in excep- 
tional cases. The bulk of the alcohol is made from 
grain or potatoes. The process is essentially identi- 
cal for all raw materials. It comprises the follow- 
ing operations : (1) Grinding of the grain without 
sifting off the bran. (2) Mashing of the grain with 
malt. Under the word malt is understood sprouted 
barley dried after sprouting, and ground. The 
sprouting of the barley grain develops another 
mysterious substance diastase which possesses the 
power to change starch into glucose more rapidly 
than sulfuric acid. Its composition is not known, 
not supposed to be a living thing as yeast. 10 parts 



ALCOHOL, SPIRITS OF WINE, ETHYLHYDROXYD. 349 

of grain, 1 part of malt, 80 parts of water heated by 
steam in a tub to 75 C. until the conversion of the 
starch is completed ; that is mashing. 

(3) To cool down the mash to 18 C. and transfer 
it to fermenting vats through a strainer. (4) Ad- 
dition of sound yeast and fermentation of the wort 
(technical name of the strained mash) in a separate 
room in which the temperature is kept evenly at 
20 to 25 C. The end of the fermentation is indi- 
cated by the collapse of the froth over the liquid. 

(5) Distillation of the alcoholic liquor in copper 
stills. Alcohol boils at 78 C., water at 100 C. 
From the boiling mixture more alcohol passes into 
vapor than water. If the liquor contains 5 per cent, 
alcohol, then this entire quantity will have gone 
over when 28 per cent, of the liquid has distilled, 
leaving 72 per cent, of liquid in the still. (This 
residue is not thrown away, but used in mixing the 
feed for fattening cattle.) ' The distillate contains 
now 20 per cent, alcohol ; is milky from minute 
drops of amyl-alcohol (fusel-oil), and not saleable. 
It must be redistilled, yielding a 40 per cent, 
brandy, and this again distilled to get a 60 per cent, 
spirit, and this again and again until a 95 per cent, 
proof spirit results. Beyond this the water cannot 
be eliminated by distillation alone. 

By mixing with fused CaCl 2 , or calcined copper 
vitriol, CuSO 4 , the water is taken up by these bodies, 
and another distillation yields absolute alcohol, 
C 2 H 5 (HO). The latter is only needed for special 
chemical purposes. The process of concentrating 



350 CHEMISTRY SIMPLIFIED. 

the alcohol by distillation is called rectification. To 
save the largest part of the fuel required, many im- 
proved processes have been invented, which at last 
resulted in an apparatus yielding proof spirit at the 
first operation. This is done by carefully cooling 
the vapors in an apparatus of large cooling surface, 
the dephlegmator, known also as a column apparatus, 
which stands directly above the still. Fusel oil and 
other complex side-products are removed from the 
alcohol in the dephlegmator. 

Properties of alcohol. A colorless, mobile liquid ; 
remains liquid even at 90 C.; boils at 78.4 C. 
Specific gravity at +4 C. = 0.8095, at +15 C. = 
0.795. 100 vols. at +4 C. give 109 vols. at 78. 
Expands therefore thrice as much as water. Taste, 
burning. Pure alcohol destroys the organisms, is 
poisonous ; dilute alcohol causes intoxication. It 
is a solvent for many substances which are not sol- 
uble in water its chief use in the laboratory. 

Chemical constitution. Analysis gives simply the 
atomic ratio C 2 H 6 0. But we write instead (C 2 H 5 ) 
(HO) because alcohol acts towards acids like the 
hydroxyds of metals. In this last form alcohol is 
meant to appear as the hydroxyd of the monovalent 
radical (C 2 H 5 ). But the latter may be looked upon 
as a complex radical made up of the simpler hydro- 
carbons CH 3 .CH 2 , or we may say that ethyl alcohol 
is equal to two groups of methyl in which one H is 
represented by the monovalent (HO) 

JCH 3 

\ CH 2 .HO. 



ALCOHOL, SPIRITS OF WINE, ETHYLHYDROXYD. 351 

One hydroxyd can take up one hydrogen of an acid, 
hence when we act upon alcohol with cone. H 2 S0 4 , 
we obtain 2(CH 3 .CH 2 .HO) + H 2 S0 4 =(CH 3 .CH 2 ) 2 . 
SO 4 + 2H 2 = ethyl sulfate or CH 3 .CH 2 .HO + 
HC1 = CH 3 .CH 2 .C1 + H 2 = ethyl chlorid. Such 
bodies were formerly named ethers, now they are 
named esters, i. e., salts in .which the metal is re- 
placed by a compound carbon radical. When 
alcohol is heated in air or oxygen, its elements 
become oxydized, it burns, producing much heat. 

CH 3 .CH 2 .HO 4- 60 = 2C0 2 + 3H 2 O. 
The absolute heat effect, A = 2 X 12 X 8240 + 6 X 
34000 = 401760 heat-units, or one gram of alcohol, 
by burning, will raise the temperature of 97.99 
grams of water from C. to 100 C., if no heat be 
lost by radiation and conduction. 



CHAPTER XX. 

SOME IMPORTANT DERIVATIVES OF ALCOHOL. 

Ether, sulfuric ether, ethyl oxyd, C*H IQ .0. This 
very important substance originates thus : 

2C 2 H 5 (HO) + H 2 S0 4 - (C 2 H 5 ) 2 S0 4 + 2H 2 0. 
(C 2 H 5 ) 2 S0 4 + H 2 + heat - C 4 H 10 + H 2 S0 4 . 

Bring into a boiling flask JOO grams concentrated 
H 2 S0 4 , 20 grams of water and 50 grams of absolute 
alcohol. This will give ethyl sulfate. Now close 
the neck with a three-hole stopper. Pass through one 
hole a long-stemmed funnel, through the second 
hole a thermometer down into the liquid ; through 
the third hole a knee-shaped gas evolution tube, and 
connect the latter by means of a proper reducer with 
a condenser. Heat until the thermometer shows 
140 C., and maintain this temperature by letting 
in absolute alcohol. Ether + water will go over 
steadily and collect in receiver. Shake the dis- 
tillate with Ca(HO) 2 -f- water, milk of lime, to neu- 
tralize acid particles. Separate the upper stratum 
of the two liquids with syphon. It contains some 
water. By redistillation in presence of CaO (burnt 
lime) the ether is obtained pure, CaO uniting with 
the water and binding it. 

Ether is a thin, very mobile, colorless liquid, of 
(352) 



SOME IMPORTANT DERIVATIVES OF ALCOHOL. 353 

strong, penetrating, but agreeable odor. Sp. G. = 
0.736. Boils at 35 C., hence very volatile. Mixes 
with alcohol in all proportions, but does not mix 
with water. 10 parts of water dissolve 1 part of 
ether. It dissolves many bodies which are neither 
soluble in alcohol nor in water, notably fats. It 
ignites easily and burns withjuminous sooty flame ; 
be careful in avoiding open flames in the neighbor- 
hood of evaporating ether. 

It is evident that ether stands to alcohol in the 
same relation as potassium or sodium oxyd to 
potassium or sodium hydroxyd, 

K 



K / ' H } ' C 2 H 5 } ' H / ' 

After once being separated it does not show any 
tendency to reconvert into alcohol. 

Ether produces unconsciousness, stupefaction, 
when the vapors are taken into the. lungs ; it is an 
anaesthetic. 

Chloroform, CHOP, can be considered as marsh 
gas in which 3H have been replaced by 3C1. It 
results when 4 parts alcohol, 3 parts water and 1 
part bleaching lime are heated in a flask or retort to 
the boiling point. With the water is found in the 
receiver a heavy, oil-like liquid chloroform. The 
reaction may go thus : 

C 2 H 6 + 2Ca(C10) 2 .CaCl 2 =CH 2 Cl 2 + 3CaCl 2 + 

CaCO 3 + 2N 2 0. 
2CH 2 C1 2 + Ca(C10) 2 CaCl 2 = 2CHC1 3 + CaCl 2 + 

Ca(HO) 2 . 
23 



354 CHEMISTRY SIMPLIFIED. 

Colorless, thick liquid. Odor pleasant, taste sweet. 
Insoluble in water. Specific gravity = 1.48. Boils 
at 61 C. Its vapors are more poisonous than ether; 
it was formerly much used as an anaesthetic. 

lodoform, CHP. A yellow solid in scaly crys- 
tals. Insoluble in water, in acids, in alkalies. 
Soluble in alcohol and ether. Used much in medi- 
cine as an antiseptic for burns and wounds. It 
originates similarly to chloroform. From a mixture 
of alcohol, KOH or NaOH and iodine. First forms 
K(IO) + KI. Then KIO acts on the alcohol just 
as Ca(ClO) 2 does. Work out equation. 

Aldehyde, C 2 H 3 HO. A thin, mobile, colorless 
liquid. Boils at 21 C. and has a suffocating odor. 
Specific gravity = 0.801. Origin : C 2 H 5 HO + 
MnO 2 + H 2 S0 4 + Aq = C 2 H 3 HO + MnSO 4 + 
2H 2 -f- Aq. In presence of air it changes into 
acetic acid, C 2 H 3 HO + C 2 H 3 2 .H. It is there- 
fore a strongly deoxydizing body. A glass plate can 
be made into a silvered mirror by pouring upon the 
well-cleansed surface a liquid composed of AgN0 3 -f 
NH 4 HO + C 2 H 3 HO + water. In this liquid we 
have Ag 2 0.2NH 4 HO + NH 4 .N0 3 + C 2 H 3 HO + 
water. Now Ag 2 0.2NH 4 HO + C 2 H 3 HO = Ag 2 + 
NH 4 .C 2 H 3 2 + NH 4 HO + IPO. 

Chloral, C 2 C1 3 HO. A colorless, thin liquid. 
Has a penetrating odor, attacks mucus membrane. 
Soluble in water. This solution does not give a 
white precipitate of AgCl when AgNO 3 solution is 
added. We explain this by saying that chlorine is 
intraradical, inside of the radical, not in the form of 



SOME IMPORTANT DERIVATIVES OF ALCOHOL. 355 

chlorid. Specific gravity 1.502. Boils at 94 C. 
Jt is prepared by passing dry chlorine into absolute 
alcohol until the evolution of HC1 stops : C 2 H 5 HO+ 
8C1 = C 2 C1 3 HO + 5HC1. When chloral is taken 
in small doses (dissolved in water), it causes a 
peculiar intoxication and indifference to pain. For 
this purpose it is given by physicians, but it can be- 
come a dangerous habit for the patient. 

Mercuric fulminate, Hg.C 2 fil 2 2 . Discovered by 
Howard, A. D. 1800. Liebig and Gay-Lussac 
found correct composition. Properties. Minute, 
white, needle-shaped crystals. Soft to the touch. 
Sweetish metallic taste. Little soluble in cold, 
more in boiling, water. Specific gravity = 4.42. 
Very poisonous. In the dry condition it explodes 
violently by friction, by a blow, or by concentrated 
H 2 S0 4 . 

Hg.C 2 N 2 2 + blow = Hg + 2CO + 2N. 
By experiment 1 gram furnished 78 c.c. of gas with 
a heat generation of 403.5 cal. or enough to heat the 
products of combustion of explosion to a temperature 
of 4200 C. Although gun-cotton gives more gas 
per unit, yet the explosive effect of the fulminate is 
much greater. This effect is often called by the 
French expression brisance. We say : Mercuric ful- 
minate is the most brisant explosive. Why ? Prob- 
ably because of its instantaneous break-up into gas. 

Preparation. We dissolve 5 grams of mercury in 
60 grams of HNO 3 specific gravity 1.34 (45 c.c.) 
which gives usHg(N0 3 ) + HNO 3 + N 2 3 + NO + 
water. When the metal is dissolved we cool the 



356 CHEMISTRY SIMPLIFIED. 

liquid to 70 C. We bring 50 grams of 90 per cent, 
alcohol into a strong, well-tempered, J-liter, round 
flask and pour the first liquid slowly into the alcohol 
while rotating the flask. A colorless mixture re- 
sults. Should no reaction develop at once we place 
the flask upon a water-bath until small bubbles 
begin to show. Then we set the flask under strongly 
drawing hood or out of the window. Usually a 
very violent reaction sets in with large masses of 
white fumes emerging from the flask. When the 
reaction is over a white, flour-like precipitate of the 
fulminate is found on the bottom of the flask. We 
cool the liquid to ordinary temperature and more 
fulminate precipitates. Then we pour off the super- 
natant liquid, wash the crystals with cold water until 
the acid reaction ceases, collect the powder on a 
filter and dry it on the water-bath or better yet, in 
a current of warm air, or still better we keep it wet. 
Manufacture of percussion caps. To reduce the 
brisance and to obtain a more penetrating flame jet, 
the fulminate is mixed with 30 per cent, of niter for 
mining caps, or 30 per cent, of potassium chlorate 
for dynamite igniters. 1. The materials are moist- 
ened with 30 per cent, water and mixed with wooden 
rubbers upon a polished slab of marble. 2. The 
paste is pressed through hair sieves and thus be- 
comes granulated. The granules are very carefully 
dried, spread upon paper. The dry granules are 
sifted through hair sieves to remove the dust par- 
ticles. 3. The granules are filled into the caps by 
special machines. The sheet copper is 0.26 mm. 



SOME IMPORTANT DERIVATIVES OF ALCOHOL. 357 

thick. The head has a small cavity Fig. A (Fig. 
101). Into this drop granules to the extent of 15 
milligrams Fig. B ; a stamp presses a thin copper 
foil over the charge Fig. C, and the cap is ready. 
This latter is the most dangerous of the operations. 

FIG. 101. 



B 



Since the charges are small, not much damage can 
ensue. Heavy charges are fired with larger caps 
containing 300, 500, 750 mgs. of fulminate charge. 
Torpedo caps contain as much as 1,500 mgs. of ful- 
minate. 

Silver fulminate, Ag 2 .C 2 N 2 2 , has similar proper- 
ties. 



CHAPTER XXI. 

SOME ORGANIC ACIDS. 

WE find these acid bodies chiefly in the flesh of 
berries or fruit, in the free state or in the form of 
salts esters. There is a multitude of them and only 
the most important ones can be mentioned here. 

Formic acid, ant acid, H.CHO 2 . A colorless, mo- 
bile liquid of very pungent acid odor. Solid at 
-1 C. Boils at 100 C. Specific gravity = 1.235. 
Causes a blister on the skin. Found in pyroligneous 
acid (wood distillation). Causes the stinging sensa- 
tion produced both by ants and nettles. It forms in 
many ways by the oxydation of organic bodies, 
especially the carbohydrates. Most interesting is 
the synthetic formation by the action of CO gas 
upon KOH at 100 C. Thus : 

KOH + CO = K.CHO 2 (potassium formate). 

Then K.CHO 2 + H 2 S0 4 + heat = KHSO 4 + 

H.CHO 2 . 

And also CO 2 + 2K + H 2 = K.CHO 2 + KOH. 
Formic acid precipitates many metals from the solu- 
tion of their salts in metallic form. HgO+H.CHO 2 
+ heat = Hg + H 2 + CO 2 . 

Acetic acid, H.C 2 H*0* or (CH 8 )COOH, a color- 
less, mobile liquid of pleasant, pungent odor. Solid 
(358) 



SOME ORGANIC ACIDS. 359 

at -f 15 C. (glacial acetic acid), boils at 109 C. 
Sp. gr. at 18 C.= 1.063. On adding water the 
specific gravity increases until 1.0748 is reached 
(acid = 78 per cent., water = 22 per cent.), then the 
gravity decreases with the addition of water until 
1.00 is reached. Hence it follows that one specific 
gravity may mean two very different acids ; for in- 
stance, 1.069 can mean an ao4d of 96 per cent, and 
an acid of 33 per cent. An acid of 54 per cent, has 
the same specific gravity as acid of 100 per cent. 
Glacial acetic acid destroys the skin as readily as 
oil of vitriol. The vapor of the acetic acid burns. 
Acetic acid dissolves many oils which are insoluble 
in water. The acetates of all metals are easily soluble 
in water, hence, lead is usually employed in the form 
of acetate. 

Acetic acid finds not only much use as vinegar, 
but also in the chemical laboratories and in the 
chemical arts, such as dyeing and printing. It is 
the oldest acid known to man, as it forms naturally 
when sugar solutions stand in a warm place in con- 
tact with air. This change does not take place 
unless a peculiar fungus mycoderma aceti is 
present. 

C 2 H 5 .HO alcohol + O 2 + ferment + water = 
C 2 H 3 2 .H acetic acid + IPO. 

Pure acetic acid for laboratory use is prepared by 
distilling two molecules of crystallized sodium ace- 
tate with one molecule of concentrated sulfuric acid 
in glass retorts ; in iron retorts for commercial use. 



360 CHEMISTRY SIMPLIFIED. 

The latter are furnished with an alembic or helmet 
made of tin. 

Na.C 2 H 3 2 + H 2 S0 4 + heat = H.C 2 H 3 2 + 
NaHSO 4 . 

The sodium acetate is, at this time, obtained exclu- 
sively from pyroligneous acid. (See distillation of 
wood or cellulose.) The pyroligneous acid is first 
made into Ca(C 2 H 3 2 ) 2 , evaporated to dryness, and 
the mass gently roasted to destroy tar oils. There- 
upon distillation with HC1 yields fairly pure acetic 
acid, containing water. This acid is neutralized 
with Na 2 C0 3 and the Na.C 2 H 3 2 is allowed to 
crystallize. The crystals are distilled with H 2 S0 4 . 
Manufacture of vinegar. Raw materials are all 
kinds of alcoholic liquids, especially wine, cider, 
spoilt beer, and fermented worts from the glucose 
industry, a. From wine. In open barrels, into 
which wine and vinegar are filled. The vinegar 
brings with it the ferment. The latter grows rapidly 
into a thick skin over the whole surface. Vinegar 
is finished in 8-14 days according to temperature of 
the room, or the outside air. b. From dilute alcohol, 
by the rapid process. The barrel B, Fig. 102, is open 
at the top. At F, F' are perforated wooden discs, 
so-called false bottoms, the space between the two 
discs being filled with clean pine shavings. The 
latter are soaked with good vinegar, and upon the 
top layer is sown a culture of pure mycoderma 
cells (all other germs are excluded). The alcoholic 
liquid is then distributed by the holes in F / over 



SOME ORGANIC ACIDS. 



361 



the surface of the shavings, while plenty of warm air 
enters through the holes 1, 2, 3, 4-, etc. The acidi- 
fied liquid is drawn from the spigot into the pail, 
and returned to the top of the barrel as many times 
as may be needed to convert the whole of the alcohol. 

FIG. 102. 




It is possible to make the resulting vinegar as strong 
as 30 per cent., in which form it is known as spirit 
vinegar, which for cooking purposes is diluted with 
10 parts of water. 

Oxalic add, H 2 .C 2 0*. At ordinary temperature 
a white, or colorless solid. Forms readily large 
crystals, monoclinic with 2 molecules of water of 
crystallization. H 2 .C 2 4 + 2H 2 0. The crystals 
show a sharp, sour taste, no odor. Soluble in 10 
parts of cold water, in three parts of boiling water. 
Soluble in 2J parts of cold alcohol, in 1.8 parts of 
boiling alcohol. The crystals lose their water of 
crystallization at 60 C. At 97 C. the crystals melt, 
at higher heat break up into CO 2 + CO and H.CHO 2 
(formic acid). In a current of air the anhydrous 



362 CHEMISTRY SIMPLIFIED. 

acid can be sublimed at 150 to 155 C. The vapors 
attack the mucous membrane and are poisonous. 

Chemical properties. Oxalic acid is not a good 
solvent for the metallic oxyds and metals, because 
the oxalates are either quite insoluble or but little 
soluble in water. The most insoluble oxalate is 
calcium oxalate Ca.C 2 4 + 2H 2 0, (quadratic crys- 
tals). This salt is not soluble in acetic acid but 
soluble in HC1. Oxalic acid is therefore our best 
agent for separating calcium from a solution. Ox- 
alic acid decomposes quickly in presence of an oxy- 
dizing agent. 

H 2 .C 2 4 + 0=H 2 



It precipitates gold and platinum from their chlo- 
rids. 

2AuCl 3 + 3H 2 C 2 4 + water = 2Au + 6HC1 + 6C0 2 

PtCl 4 + 2H 2 C 2 4 + water = Pt + 4HC1 + 4C0 2 

H 2 C 2 4 + H 2 S0 4 + heat = CO 2 + CO + 

H 2 S0 4 .H 2 

(best way to get pure CO for experiments, the CO 2 
being removed by means of NaHO). 

Occurrence of oxalic acid. It is found in the saps 
of many plants, as KH.C 2 4 , especially in the 
leaves of sour clover (oxalis), and in rumex ; also in 
rhubarb (as CaC 2 4 ). It forms the calculi in the 
bladder and kidneys of man. 

Manufacture. There are two ways. (1) By action 
of nitric acid upon the carbohydrates sugar, starch, 
wood. 



SOME ORGANIC ACIDS. 363 

C i2 H 22 n ) sugar + 12HN0 3 + water = 
6H 2 C 2 4 , oxalic acid + 11H 2 + 12NO. 
Theoretically 1 part of sugar requires 2.21 parts of 
HNO 3 or 5 parts of 50 per cent. acid. Practice 
shows that 6 parts are needed to effect complete oxy- 
dation. Reaction is energetic after once started. 
When evolution of gas has gone down, put flask on 
flame and boil until volume o'f liquid is J of original. 
On cooling, the acid crystallizes. (2) By action of 
KOH -f- NaOH upon sawdust or similar refuse 
wood. The action is probably as follows : 

C 6 H 10 5 , cellulose + 2KOH + 2NaOH + heat = 
Na 2 .C 2 4 + K 2 C0 3 + 2CH 4 + CO + H 2 0. + 4H. 

The temperature should not be above 240 C. to 
obtain the best result. At a higher temperature 
Na 2 C 2 4 changes to Na 2 C0 3 + CO. When all the 
wood is changed, let cool. Extract with little cold 
water, which dissolves only K 2 C0 3 . Then dissolve 
residue in boiling water and stir with an equivalent 
of Ca(HO) 2 . 
Na 2 C 2 4 + water + Ca(HO) 2 + boil = Ca.C 2 4 + 

2NaHO. 

Filter. Filtrate is evaporated for next batch. 
Residue is decomposed by dilute H 2 S0 4 giving 
CaSO 4 + H 2 C 2 4 . Separate the liquid (hot) from 
the solid CaS0 4 .2H 2 by means of a filter press or 
centrifugal. Evaporate filtrate until crystals appear, 
then let cool, and the bulk of the oxalic acid will fall 
out, and after air-drying can be packed and shipped. 
In spite of the many operations, this second method 



364 CHEMISTRY SIMPLIFIED. 

gives the acid at considerably less cost than the first 
method. 

Lactic add, milk acid, H*.(C*H* s ). A colorless, 
thick liquid. Strong sour taste ; no odor when 
pure. Specific gravity = 1.25. Soluble in water, 
alcohol, ether. When the water-solution is evapo- 
rated a part of the acid escapes with the vapor, but 
most of it remains as a syrup. At 130 C. it loses 
one H 2 and becomes so-called anhydrous acid, 
Q6JJ10Q5 (isomeric with glucose, starch). 

Lactic acid can be separated from other acids by 
the insolubility of some of its salts, especially 
Sn.C 3 H 4 3 . The calcium lactate is somewhat sol- 
uble in cold and more soluble in hot water. Lactic 
acid is found in sour milk ; in the gastric juice ; in 
certain fermented vegetables, such as cabbage and 
turnips. It forms easily from glucose or any other 
sugar in presence of the lactic ferment. The latter is 
obtained from rotten cheese or rotten meat. 

Tartaric acid, wine acid, H 2 .C 4: H 4: 6 . As solid, 
in colorless, monoclinic crystals. Easily soluble in 
water, much less in alcohol, and not at all in ether. 
The water-solution rotates the plane of polarization 
to the right. Strong sour taste. Melts at 170 C., 
forming a vitreous body meta-tartaric acid with- 
out decomposition. If we add tartaric acid to .a 
solution containing a ferric or aluminic salt, and 
then an excess of NH 4 HO, there will be no precipi- 
tate, enabling the chemist to effect certain separa- 
tions, otherwise difficult. 

Salt of seignette, Na.KC*H*0 + SH 2 0. Large 
crystals showing orthorhombic hemihedry. 



SOME ORGANIC ACIDS. 365 

Calcium tartrate, Ca.C*H*0 + 8H 2 forms by 
adding lime water to a tartrate solution. Insolu- 
ble in water. 

Tartar emetic, K(SbO)C 4 H 4 6 + JJ? 2 soluble in 
14 parts of cold water, in less boiling water. Ob- 
tained by boiling a solution of ordinary tartar 
(K.H.C 4 H 4 6 ) with Sb 2 3 ,-the teroxyd of anti- 
mony. Used as an emetic ; causes death in larger 
portions. 

We obtain the tartaric acid from the tartar or 
argol which is the name of the hard, stony deposit 
in the casks in which the grape juice has been fer- 
menting. The Germans call it weinstein, winestone. 
The crude tartar is a mixture of the acid potassium 
tartrate KH.C 4 H 4 6 with coloring material and 
yeast cells, and calcium tartrate. The tartrates 
were originally dissolved in the juice but had to fall 
outin measure as the percentage of alcohol increased, 
they being insoluble in the latter. 

We boil the fine powder with 15 parts of water 
for some time, add bone-black or charcoal which ab- 
sorbs the coloring matter, and filter boiling hot. 
From the filtrate precipitate small crystals of 
KH.C 4 H 4 6 . They go under the name cream of 
tartar. We redissolve in boiling water, add one 
equivalent of Ca(HO) 2 and keep boiling until we 
have KOH + insoluble Ca.C 4 H 4 O 6 . We separate 
by H 2 S0 4 after filtering, getting CaS0 4 .2H 2 + 
H 2 .C 4 H 4 6 , and proceed the same as for oxalic acid. 

The crude tartar is used in assaying as a deoxy- 
dizing agent and alkaline flux, for on heating in a 



366 CHEMISTRY SIMPLIFIED. 

covered crucible to redness a decomposition takes 

place, 

2KH.C 4 H 4 6 + red heat = K 2 C0 3 + 3G + 4CO + 

5H 2 0. 

Both C and CO act as deoxydizers upon metallic 
oxyds ; while K 2 CO 3 can take up sulfur or silica, 
or both. 

Citric acid, H*.C Q H 5 7 . A tribasic acid. Large 
colorless crystals, orthorhombic combinations 
H 3 .C 6 H 5 7 + 2H 2 0. Very sour taste. Easily 
soluble in water and in alcohol. The acid acts in 
iron solutions and aluminum solutions the same as 
tartaric acid. It is used for a number of medical 
preparations, especially seidlitz powders, magnesium 
citrate and others. Contained in sour lemons, in 
gooseberries. 

Preparation. . The juice is pressed from sour 
lemons, strained and neutralized with Ca(HO) 2 . 
The calcium citrate is nearly insoluble in water, and 
is decomposed like the tartrate and oxalate with 
H 2 S0 4 . 

Malic acid, H 2 C 4 H*0 5 . Imperfect crystals, re- 
sembling cauliflower. Deliquesces in the air, form- 
ing a syrup. Very sour. Soluble in alcohol. 
Occurs in many fruits, especially in sour apples, 
plums, gooseberries, etc. Calcium malate is easily 
soluble, and forms large crystals. This enables the 
separation of the acid. Insoluble lead malate is, as 
a rule, prepared and decomposed with IPS. 

Tannic acid, tannin, C 14 H 20 IB . An amorphous 
powder; color pale-yellow or brownish ; somewhat 



SOME ORGANIC ACIDS. 367 

shining. Taste very astringent. Very soluble in 
water, barely soluble in ether, very slightly in 
absolute alcohol. Its water-solution gives with 
Fed 8 or with FeSO 4 a blue-black color and later a 
blue-black precipitate, insoluble in water. Its solu- 
tion gives a flocculent precipitate with a solution 
of gelatine. If a piece of fresh skin or hide is 
placed in the tannin solution, the tannin will grad- 
ually leave the liquid and precipitate itself on the 
skin. The tannin is easily oxydizable, and there- 
fore reduces CuO to Cu 2 in presence of NaHO, or 
KHO, and gives Ag with AgNO 8 , same as glucose. 
Hence chemists place the tannin among the gluco- 
sids. Its chief use in medicine is as an astringent in 
affections of the mucous membrane. It is used to 
make our ordinary black ink. We obtain the 
tannin from the so-called Turkish nut-galls. The 
latter form on the leaves and twigs of certain plants, 
especially oak and acacia, after a sting has punctured 
the leaf. The sting comes from wasps mostly, who 
deposit their eggs in the outflowing sap. The sap 
hardens and forms the nut-like excrescence or 
growth. The nut-galls contain as much as 65 per 
cent, of tannin. 

Preparation. We extract the ground galls with a 
mixture of 30 volumes of crude ether (0.74), 4 vol- 
umes of water, 1 volume of alcohol (90 per cent.). 
The extract separates into a lower layer, a syrup 
(tannin and water) forming the upper layer is com- 
posed of ether-alcohol with a little tannin and all 
other bodies. The water-syrup is evaporated and 
leaves shining amorphous tannin. 



368 CHEMISTRY SIMPLIFIED. 

Recipe for black ink. 125 grams of ground nut 
galls, 24 grams of copperas (FeSO 4 -f 7Aq.) 24 
grams gum-arabic, 1 liter of water, 1 gram of creo- 
sote. Boil the materials for 1 hour, replacing the 
evaporating water. Strain through a hair sieve or 
through muslin. Let settle for a week, then put up 
into bottles. 

Tanning bodies similar, yet not quite identical with 
tannin are contained in the barks of many trees, 
especially the oak, the hemlock, the willow. In the 
tanneries the hides are first cleansed from the hair 
and adhering parts of flesh, together with the upper- 
most layer of cells the cuticle by scraping. The 
clean skins are spread in water-tight pits so that a 
layer of ground bark is between two skins, as many 
as 100 skins in 1 pit. Then the pit is filled with 
water and allowed to stand quietly for several months, 
the longer the better. The water draws the tanning 
bodies from the bark and the skins take it from the 
water-solution. By cutting off a bit of the skin one 
recognizes from the cross section, whether the change 
has taken place to the very core. Then the skin 
has become leather. It is perfectly proof against 
putrefaction. It has become impenetrable to water 
and yet it remains pliable when dried. A similar 
change takes place in the skin in presence of alum, 
ferric sulfate, and chromium sulfate. So that we 
have now tan, iron, chrome, alumina leather. The 
scarcity of bark has brought into use these substi- 
tutes. 

Gallic acid, H.C 7 H*0 5 + H 2 crystallizes in 



SOME ORGANIC ACIDS. 369 

silky needles of the triclinic system. Colorless or 
pale yellow. Soluble in 3 parts of boiling water, 
slightly soluble in ether or alcohol. Action on metallic 
solutions in presence of NaHO or KHO or NH 4 HO 
like tannin, somewhat more energetic. Forms well 
crystallized metallic salts. It is found ready in 
sumac and other plants. Prepared by allowing a 
solution of tannin to cover itself with fungi (mildew) 
in presence of yeast. 

Pyrogallic acid, pyrogallol, H.C*H*0 3 . A fluffy 
mass of thin scales and needles. Soluble in 2.2 
parts of water at 15 0. Solution colorless. Fed 3 
gives a blue color with this body ; free N 2 3 pro- 
duces a brown color. All oxydizing agents produce 
a brown color. An alkaline solution turns brown 
at once in air. It acts more energetically upon 
metallic solutions than the preceding ones. This 
gives its high value as a developer in photography. 
Here the AgBr on the plate becomes changed by 
the action of light and becomes capable of decom- 
posing water in presence of pyrogallate. 2(AgBr) 
active + H 2 + Na.C 6 H 5 3 = Ag 2 + 2HBr -f 
Na.C 6 H 5 4 (the brown body); the ordinary AgBr 
is not changed. 

Preparation. By heating gallic acid thus : 
H.C 7 H 5 5 + H 2 + heat = H.C 6 H 5 3 + 

CO 2 + H 2 0, 

hence name pyrogallic from pyro = fire. 
24 



CHAPTER XXII. 

THE VEGETABLE FATS AND ANIMAL FATS. 

MANY plants develop in their seeds an oily sub- 
stance, in the place of starch, for the nutrition of 
the embryo plant ; the cotton, flax, hemp, rape, 
sesame, anise, poppy, mustard, and among the trees 
all the so-called nut-bearing kinds : palm, walnut, 
beach, hickory, olive, plum, peach, almond and 
many others, while some grow oil-bearing roots such 
as the pea-nut. After removing the hard shell from 
the nuts the soft kernels are crushed between rolls 
of iron or stone, the pulp is warmed to about 60 C, 
put into strong hair cloth and pressed by mechani- 
cal or hydraulic devices. The oil runs off. The 
remaining cake is very nutritious, containing still a 
good deal of oil. It is often fed to the cattle, or 
used as manure after the oil has been fully extracted 
with carbon disulfid. Immense quantities of these 
oils are made annually in Europe ; in the United 
States cotton-seed oil and linseed oil (flax) are the 
only ones. Most of the plant oils remain thick 
liquids at ordinary temperature, some become pasty 
(palm-oil) and a few are solids. 

All fats and oils repel water, and are practically 
insoluble in water. They dissolve in alcohol, in 
ether and in carbon disulfid. Their specific gravity 
(-370) 



THE VEGETABLE FATS AND ANIMAL FATS. 371 

is mostly smaller than that of water. Between the 
fingers they produce a slippery sensation, hence 
they lubricate, i. e., reduce friction. They taste 
pleasantly or unpleasantly, and each oil has a differ- 
ent odor or flavor. However, taste and flavor are 
produced mostly by small quantities of special oils, 
flavoring oils essential oils., while the mass of the 
fat varies but slightly in composition and quality, 
yet often considerably in the relative quantities of 
its constituents. Hence each oil has a specific boil- 
ing-point, and also a different fluidity viscosity 
which is measured by the quantity of the oil which 
will run through a nozzle of standard diameter 
in one minute at standard temperature. 

TJie animal organism develops fat upon and be- 
tween the muscles, in the hollow bones, partly as 
lubricant, partly as a non-conductor of heat, partly 
as a food store (sick persons lose their fat first, be- 
cause the body lives upon it when the digestive 
organs are out of gear). The nerve substance, brain 
substance is fat, and the yoke of the egg is a yellow 
liquid fat upon which the embryo of the oviparous 
animals feeds. Viviparous animals have no eggs, 
because the embryo cell receives its nourishment 
from the mother's blood through the navel chord. 

The animal fats are solid at ordinary temperature 
or at any rate pasty. The fat lies in form of glob- 
ules within a loose tissue of large cells. In heating 
the fat the cells break, the globules unite into one 
mass and the cell substance (fibrin, chondrin), coag- 
ulates and comes to the surface as brown scum. 



372 CHEMISTRY SIMPLIFIED. 

Otherwise the animal fats act like the vegetable 
fats or oils. 

Chemical action of fats. The fats prove themselves 
to be esters or salts, in which fat acids of the marsh 
gas series, C n H 2n 2 , with high value of n, are 
united with glycerin, which has the properties of a 
triatomic alcohol. 

/ A 
A fat is G A or G.(A) 3 

X A 

when G stands for glycerine and A for a monatomic 
fat acid radical. This view is deduced from the 
action of metallic hydroxyds upon the fats. (1) 
NaOH + Aq + fat -f boiling heat yields after 
sufficient boiling a thick paste, soap, which is com- 
pletely soluble in much water, and quite soluble in 
a few volumes of alcohol. Upon adding HC1 or 
JPSO 4 (dilute) to the solution in water, a white 
flocculent body separates. If the liquid be heated 
to near boiling point, the white substance melts, 
rises to the surface and forms there a layer of oil. 
On cooling the oil becomes solid or semi-solid, and 
represents the fatty acids. The liquid contains 
NaCl + HC1 + water + glycerin. The glycerin 
was discovered by the Swedish chemist Scheele 
about 130 years ago. Being an apothecary he had 
to make adhesive plasters by boiling olive oil or 
other fats with lead oxyd. In this process the fat 
acid combines with PbO into a pasty, sticky body, 
which is quite insoluble in water. Spreading the 
paste upon linen, muslin or silk, makes the plaster. 



THE VEGETABLE FATS AND ANIMAL FATS. 373 

Now Scheele noticed one day that the water, with 
which he had washed the plaster, possessed a sweet- 
ish taste, and this led him to work until he had 
separated this sweet body in the form of a thick 
liquid, by evaporation ; and because of the sweet 
taste he named it glycerin from glucos = sweet. 
He knew it was not sugar because it would not give 
alcohol with yeast. The composition and chemical 
nature was established long afterwards by J. Liebig 
and others. Accordingly, we know at present that 
glycerin has a composition represented by the sym- 
bol C 3 H 8 3 ; that towards acids it acts like a 
base a hydroxyd, with 3 replaceable hydrogen 
atoms, and hence we write: C 3 H 5 (HO) 3 with the 
probable constitution CH 2 (HO).CH(HO).CH 2 (HO). 
Properties. At ordinary temperature a syrup. At 
a very low temperature an orthorhombic solid, which 
only melts at 17-20 C. Boils at 290 C., and 
distills without decomposition ; more readily in a 
current of steam. At 150 C. it ignites on approach- 
ing a flame and burns with a pale blue, non-lumin- 
ous flame. If salts are present the glycerin breaks 
up during the distillation, thus C 3 H 8 3 -f heat = 
C 3 H 4 -f- 2H 2 0. The product is avrolein, a very 
disagreeably smelling substance (the odor arising 
from a glowing wick). Glycerine mixes with water 
in all proportions, is soluble in alcohol. Not soluble 
in ether nor in chloroform. Pure glycerine is hygro- 
scopic, attracts water from the air, hence it causes a 
burning sensation on the m ucous membrane. Diluted 
with 1 volume of water it is pleasant on a chapped 



374 CHEMISTRY SIMPLIFIED. 

skin because it does not become dry, keeps the new 
skin from chafing. Chemical reaction : A borax 
bead moistened with glycerin colors flame green ; 
without glycerin colors flame orange-yellow. 

Preparation. Boil 90 grains of olive oil with 50 
grams of lead oxyd and 50 grams of water until the 
oil has disappeared, the plaster formed. Then add 
more water, boil a few minutes, let cool and drain 
the Water through a filter. Pass H 2 S through the 
liquid to remove any dissolved lead, filter, evaporate 
below the boiling-point, and at last heat the syrup 
at 100 C. to constant weight. 

Manufacture of glycerin is a part of the manufac- 
ture of stearic, oleic, and palmitic acids. These re- 
actions constitute the base of the process : 

1. Saponification as above with hydroxyds. 

2. Stearate + H 2 S0 4 + water + heat = stearic 
acid -j- glycerin -f- sulfate -j- water. 

3. Stearin -f water + heat + pressure = stearic 
acid -f- glycerin + water. 

The last reaction gives the best results. It is 
carried on in 2 cylindrical steel-plate boilers. As 
much as 1000 Ibs. of fat can be taken at one opera- 
tion. The boilers stand one above the other verti- 
cally, and communicate by means of 2 tubes so that 
the materials circulate and the temperature equal- 
izes.. The temperature is 200 C. and the pressure 
accordingly 15.3 atmospheres or about 230 Ibs. per 
sq. inch. Time of action 10 hours. The molten 
fatty acids collect above the watery glycerin, the latter 
is drawn off at the bottom, evaporated in a vacuum, 



THE VEGETABLE FATS AND ANIMAL FATS. 375 

and furnishes at once a commercial glycerin. It 
has a yellow color and contains quite a number of 
other organic bodies in small quantities. Best puri- 
fication by means of crystallization at -f 2C. and 
separation of crystals from mother-liquor by means 
of centrifugal machine. 

Tri-nitro-glycerin, C*H 5 (NO*)*, an oily liquid at 
ordinary temperature, but capable of solidification 
below the freezing-point. Insoluble in water. 
Easily soluble in ether. Very explosive by friction 
or blow. Begins to vaporize at 75 C. The vapors 
when taken into the lungs cause headache, sick 
stomach. Tri-nitro-glycerin influences the action of 
the heart, and is used by physicians in cases of col- 
lapse. It has become the most important explosive 
for blasting since Nobel conceived the idea of letting 
the oily nitro-glycerin be soaked up by infusorial 
earth (4 parts of the oil, 1 part of the earth). In 
this form it is known as dynamite. The white 
blasting powder now in use in many mines con- 
tains : Nitro-glycerin 45-55 per cent.; soda niter 
25-30 per cent.; wood pulp 15-20 per cent.; mag- 
nesia 2-3 per cent. Wood pulp takes the place of 
infusorial earth, and the niter burns up the wood in 
the explosion. Such a composition is not as effective 
as dynamite, but on the other hand it can be 
handled with less danger, and it does not shatter 
the rock as much as dynamite. Nitro-glycerin dis- 
solves gun-cotton, yielding a jelly-like material 
known as blasting gelatine. The latter can be 
changed into a hard, horny material, granulated, 



376 CHEMISTRY SIMPLIFIED. 

and then forms, with the addition of ammonium 
picrate, the so-called smokeless powder. 

Manufacture of nitro-glycerine. Reaction : 
C 8 H 5 (HO) 3 + 3HN0 3 = C 3 H 5 (N0 3 ) 3 + 3H 2 0, 
temperature 10 C. to 20 C. Operation: Prepare 
a mixture of 30 parts of 95 per cent. H 2 S0 4 with 
28 parts of fuming HNO 3 (Sp. Gr. 1.48). Cool this 
mixture to 10 C., weigh out 10 parts of glycerin, 
stir together with 0.3 parts of concentrated H 2 S0 4 . 
Pour the glycerin sulfate in a thin stream, or drop by 
drop, into the acid mixture while stirring the latter 
with a thermometer. The temperature rises 
should it rise above 20 C., stop pouring and cool 
the liquid, then finish pouring. The result is an 
emulsion or milky liquid which soon begins to 
separate into two distinct layers. The upper layer 
is tri-nitro-glycerin ; the lower layer is sulfuric acid, 
which retains some nitric acid. After some hours' 
standing the acid part is discharged from the mixing 
vessel, and the nitro-glycerin run into cold water, 
washed several times, and finally with a 5 per cent, 
solution Na 2 C0 3 to remove last traces of acid. 
There must be no brown fumes during the mixing. 
Their appearance means danger. The sulfuric acid 
serves to take up the 3H 2 of the process, so that 
the HNO 3 retains its concentration. It can be used 
over and over if the water is boiled out of it. 

Tallow (from beef or mutton) contains three dif- 
ferent fats: 1. Stearin, C Z H 5 .(C 18 H* 5 O 2 ) 3 , glyc- 
erin tri-stearate. A hard, white crystalline solid at 
ordinary temperatures ; melts at 55 C. then returns 



THR VEGETABLE FATS AND ANIMAL FATS. 377 

to solid condition, but at 71.6 C. is permanently 
liquid. 

2. Palmitin, C*H 5 .(C 1 H* 1 2 )*, glycerin palma- 
tate. Scaly crystals ; white, luster of mother of 
pearl. Melts at 46 C., then solidifies, and becomes 
permanently liquid at 62.8 C. 

3. Olein=C*H 5 .3(C l *H* 3 2 ), glycerin tri-oleate. 
Pure olein, is a colorless oil without either taste or 
smell. In contact with air it absorbs oxygen and 
turns " rancid" by separation of "free" oleic acid. 
Oleic acid belongs to the series C n H 2u - 2 2 . 

Soap, saponification. Soap results from the change 
of the glycerin esters into sodium or potassium 
esters, by the action of NaOH or KOH : 

C 3 H 5 .(C 18 H 35 2 ) 3 , stearin + 3NaOH = 
3Na(C 18 H 35 2 ), soap +C 3 H 5 (HO) 3 glycerin. 

890 parts of stearin require 120 NaOH ; 100 parts of 
stearin require 13.4 parts NaHO and furnish 10.3 
parts of glycerin ; while the quantity of soap de- 
pends upon how far the water is removed by the 
process of boiling and salting, for in a solution of 
NaCl soap is more and more insoluble as the per- 
centage of NaCl rises in the liquid. This distin- 
guishes soft from hard soap. The process of chang- 
ing fat into soap is named saponification. 

Drying oils. The oils from flax seed, poppy seed 
and some other plants, differ from other oils in so 
much as they become dry in a day or two when spread 
over wood or any other solid material. The surface 
has become covered with an elastic film. A second 



378 CHEMISTRY SIMPLIFIED. 

and third coating increases the thickness of the film. 
The latter shows luster and is known as varnish. 
Other oils, such as olive oil, nut oil, etc., do not dry," 
they turn rancid and continue to be greasy fora long 
time. Hence linseed oil or poppy seed oil is used 
as the liquid medium in painting. The oil is mixed 
intimately with the colored solids oxyds, salts, earths 
after the latter have been ground to exceedingly line 
grain. The chemical reason for this drying lies in 
the fact that the chief part of drying oils is made up 
of linolein instead of olein. Linolein is C 3 H 5 .- 
(C 16 H 27 2 ) 3 . The linoleic acid is H(C 16 H 27 2 ) 
and is known as an unsaturated acid belonging to 
the series C n H 2n ~ 4 2 . The acid absorbs oxygen 
rapidly and becomes oxy linoleic acid; the latter being 
the varnish. 

Turpentine, spirits of turpentine, resin, balsam. All 
coniferous plants exude from their bark an oily 
liquid, which soon becomes sticky and ultimately 
a transparent solid. The pitch-pine of the Southern 
States and the Canadian balsam fir produce this 
material more abundantly. By means of cuts in 
the trees the liquid is collected in the woods (same 
as maple sap). It is usually a thick liquid of pale 
yellow color and strong pleasant odor. This tur- 
pentine or balsam contains an oil named spirits of 
turpentine and a solid known as resin or rosin. 
The oil is obtained by distillation, usually in a cur- 
rent of steam. The residue contains several similar 
bodies insoluble in water, but soluble in part in 
absolute alcohol, and partly insoluble. The Canada 



THE VEGETABLE FATS AND ANIMAL FATS. 379 

balsam contains oil = 24 per cent.; resin soluble 
in absolute alcohol = 60 per cent.; insoluble resin 
= 16 per cent. Spirits of turpentine, a clear, color- 
less, mobile liquid, sharp taste, peculiar pleasant 
odor. High refraction. Insoluble in water, little 
soluble in alcohol, easily soluble in ether, chloro- 
form, carbon disulfid. Boiling-point varies between 
160 to 180 C. Specific gravity=0.85 to 0.89. Ro- 
tates plane of polarization. The substance may be 
represented as a hydrocarbon, C 10 H 16 , but is evi- 
dently a mixture of several hydrocarbons, which 
have not been separated from each other. Turpen- 
tine evaporates very rapidly in air at ordinary 
temperature and leaves a film. Hence it is known 
by painters as a quick dryer when used for dilut- 
ing paint. Its chief use is in the manufacture of 
different varnishes, because it dissolves the resins. 

Rosin, pine rosin, colophony. Obtained from the 
heating or distilling of the turpentine. A hard, 
brittle substance, of yellow to brown color, sticks to 
the mortar and pestle when grinding. Specific 
gravity 1.01 to 1.08. Insoluble in water. Softens 
when heated, then melts. Soluble in spirits of tur- 
pentine, in absolute alcohol, in ether, etc. Chem- 
ically this substance must be considered as an acid 
alcoholic solution reddens litmus. This body 
has been named abietinic acid, C 44 H 62 4 +H 2 0. 
It combines with the metallic hydroxyds to form 
soluble and insoluble salts, esters. With KOH 
or NaOH results soluble (water) potassium or 
sodium abietinate; with Ca(HO) 2 ,Pb(OH) 2 , etc., 



380 CHEMISTRY SIMPLIFIED. 

result insoluble bodies. The acid is, therefore, 
analogous with the fatty acids. Rosin is frequently 
added in soap-making. 

Pitch is the name given to the somewhat elastic 
body obtained by the destructive distillation of rosin, 
or resinous wood. 

There are a great many other rosin-like substances 
from other plants, each with peculiar properties. 
They are all used in making varnishes. 

Rubber, caoutchouc, gutta-percha. Obtained by 
evaporation of the milky sap of certain tropical 
trees, and of immense importance to modern civili- 
zation. The gutta-percha tree is from 40-70 feet 
high. The leaves are inverted, oval and leathery. 
By means of incisions at different heights the sap is 
made to flow. It sets or coagulates shortly after 
leaving the tree and then dries out into a tough, 
elastic, light-colored, leathery substance which is 
impermeable to water, therefore even the natives 
knew how to make flasks and bottles of it. Rubbing 
causes negative electrification. Very poor conduc- 
tor. In contact with air it absorbs oxygen, increases 
in weight, becomes brittle. Under gentle heat the 
gutta-percha becomes soft and plastic, whence its 
great serviceability. Melts at 120 C. into a thin 
liquid ; at higher heat forms vapors of a disgreeable 
odor. The analysis of pure gutta gave C, 86.36 ; 
H, 12.15 ; O, 1.49. The great mass of the gutta is 
probably a hydrocarbon, the oxygen belonging to a 
secondary body. C 6 H 10 is probably the nearest ap- 
proach to the formula. The gutta is somewhat 



THE VEGETABLE FATS AND ANIMAL FATS. 381 

soluble in absolute alcohol. Easily soluble in 
chloroform and carbon disulfid. 

Under the name caoutchouc (Indian) goes a variety 
of rubber which comes from the milk-sap of a num- 
ber of trees belonging to different families and quite 
unlike the gutta plant. Some of the trees are of 
enormous size, 135 feet high, 25 feet diameter. One 
tree can produce as much as" 60 Ibs. of rubber per 
year without suffering. The fresh sap has an acid 
reaction. Contains in 100 parts caoutchouc = 31.5 ; 
albumen = 2.0 ; a bitter substance = 7.0 ; insoluble 
in water and alcohol = 3.0 ; water = 56.5. Hand- 
ling of sap : The sap is mostly spread upon boards 
and dried upon a slow fire ; the resulting film is 
drawn off, and many films are kneaded into one mass 
with water. By another method the sap is allowed 
to stand 24 hours. The rubber rises to the top and 
looks like cream, (a double volume of water having 
been first added). The water is let out at the bottom 
and fresh water is added until it runs off clear. A 
solution of alum is then added to the cream, and the 
the caoutchouc separates. It is kneaded to remove 
the liquids and then dried, but often retains much 
w;ater when it reaches the factory. 

Caoutchouc contains the hydrocarbon C 6 H 10 in 
varying proportion depending on the species of 
plant, upon the local climate, the soil, and especi- 
ally the treatment of the sap. Physical properties : 
High elasticity, transparency in thin sheets. Indif- 
ference towards acids and alkalies except the con- 
centrated H 2 S0 4 , HNO 3 at elevated temperature. 
Easy adherence of two fresh surfaces (making of 



382 CHEMISTRY SIMPLIFIED. 

tubes). Impermeable to water, but permeable to 
gases. Pure rubber changes on exposure to light and 
air into a more or less brittle body. Can be restored 
somewhat by exposure to the vapors of alcohol. 

Vulcanizing of rubber. The fact that rubber be- 
comes soft and smeary at a relatively low heat reduces 
its usefulness. This defect can be remedied somewhat 
by impregnating it with sulfur. In molten sulfur the 
the rubber takes up as much as 15 per cent. S. But 
it also absorbs sulfur if the latter in the form of fine 
powder is kneaded together with the fine-cut rubber 
and then rolled out into sheets or blocks. Thus 
prepared the material is less permeable to gases and 
does not get smeary when warmed. Ink eraser is 
made by adding fine quartz sand to the sulfur. 
Zinc oxyd, or prepared chalk are kneaded into the 
rubber to make strong tubes and steam-packing 
washers. A solution of sulfur in CS 2 or SCI 2 in 
contact with fine-cut rubber gives sulfur to the 
latter. The actual vulcanization consists in heating 
(baking) the impregnated rubber to a temperature 
of from 146 to 170 C. 

Hard rubber, ebonite. A horn-like, usually black 
substance in which one does not recognize any of 
the usual properties of rubber. Replaces wood, 
glass, leather, horn, ivory for many articles, notably 
combs. Can be pressed to assume almost any shape. 
Excellent non-conductor for electricity. 6 parts of 
rubber are kneeded with 3 parts of sulfur, 1 part of 
zinc sulfid or other material, then heated for several 
several hours to 140 C., and pressed in iron 
moulds. 



CHAPTER XXIII. 

ORGANIC ALKALOIDS. 

THESE bodies are of special interest as strong stim- 
ulants or direct and fatal poisons. Combine with 
.acids to form easily crystallizing salts nearly all 
soluble in water. Some turn red litmus to blue. 
They are the direct products of certain plants, in 
which they are found as salts of organic acids. 

Theobromin, C 7 H*N*0 2 . The stimulating sub- 
stance in cocoa and hence in chocolate. Is very 
slightly soluble in water, its reaction is neutral. 

Caffein, C 8 H 10 N 4 2 . The stimulant in coffee 
and in tea. The tea-leaves contain as much as 4 
per cent.; the coffee bean only one per cent. It is 
not a strong base ; the salts are decomposed by water. 

Urea, CH*N 2 0. Colorless, orthorhombic prisms. 
Specific gravity 1.45. Taste cooling like niter. 
Easily soluble in water. Reaction neutral. Com- 
bines with acids to salts, which are mostly little 
soluble in water, especially the precipitates produced 
by AgNO 3 and Hg(N0 3 ) 2 . Urea is the principal 
substance contained in urine. 

Morphin, C l ^H 1 9 A T 3 . White or colorless ; little 
soluble in water, but easily soluble in acids. Is a 
narcotic or sleep producer ; overdose is fatal. Con- 
tained in opium, and opium itself is the result from 
(383) 



384 CHEMISTRY SIMPLIFIED. 

drying the sap which runs from unripe seed cap- 
sules of the poppy. 

Chinin or Qainin, C 20 H 24 N 2 2 . White solid, 
slightly soluble in water with blueing of litmus ; 
strong base. Easily soluble in acids chinin sul- 
fate forms white, fluffy needles, and is usually taken 
as a remedy for malaria or other fevers. Chinin is 
extracted from the bark of a shrub growing in Peru. 

Strychnin, C 27 H 22 N 2 2 . Colorless prisms, nearly 
insoluble in water and only slightly in alcohol or 
ether. Soluble in acids. The sulfate is used in 
medicine in minute doses. 50 milligrams of the 
sulfate constitute a fatal dose, inasmuch as the 
strychnin causes terrible convulsions and lock jaw. 
It is developed in the fruit and seeds of the strychin 
plant. 

Brucin, C 2S H 26 N 2 0* + 8H 2 0. Colorless tetra- 
gonal prisms. Easily soluble in alcohol and ether, 
slightly soluble in water. Reaction : Brucin -f- 
HNO 8 gives red body, which turns into a purple 
precipitate on adding SnCl 2 . Made use of to detect 
nitrates. Brucin is found with strychnin in the 
beans of the Strychnos Ignatii. Brucin is poisonous 
but not so violently as strychnin. 

Atropin, C 17 H 2S NO S . Needle-shaped prisms, 
silky luster. Tastes very sharp and bitter. Salts 
do not crystallize readily. Is very poisonous. When 
applied in dilute solution to the cornea of the eye the 
pupil becomes enlarged, so that the iris seems to dis- 
appear. It is extracted from the cherry-like fruit of 
atropa belladonna, (belladonna signifies handsome 



ORGANIC ALKALOIDS. 385 

lady because the ladies of fashion have made use 
of the extract to make their eyes more fascinating). 

Cocain, C 11 H BI NO*. Colorless prisms soluble 
in alcohol. Is extracted from the coca leaves. Pro- 
duces local stupefaction of the nerves and is there- 
fore used to relieve pain. 

Nicotin, C 10 H 14 N 2 . A colorless oily liquid, usu- 
ally yellow because not quite pure. Odor pene- 
trating, disagreeable ; soluble in water, in alcohol. 
Changes red litmus to blue. A strong base. Boils 
at 250 C. Very poisonous. A small dose acts as 
a narcotic. Extracted from the leaves of tobacco. 
Fine Havana tobacco contains only about 2 per 
cent. Coarse common tobacco as much as 7 per 
cent. A poultice of tobacco leaves on any part of 
the body can cause convulsions and even death. 
The smoking tobacco has been fermented, most of 
the nicotin is therefore destroyed and NH 3 is formed. 
25 



OF THE 

UNIVERSITY 

Of 




CHAPTER XXIV. 

ALBUMEN AND ALBUMENOIDS. 

The animal body is composed, from the chemical 
standpoint, of fat, muscles, bone and derivatives of 
the muscles. The muscles or flesh, as well as the 
skin, hair, tendons, are composed of albumenoids ; 
the bone is calcium phosphate. 

Albumen, C 72 JET 112 JV 18 S 2 22 . Is obtained by 
evaporating the white of eggs at a temperature not 
exceeding 50 C., and thus, 

C 72 H 112 N 18 S 2 22 

obtained represents a yellowish transparent mass 
with a specific gravity of 1.314. With water it 
swells and then dissolves. It has an alkaline reac 
tion (due to the presence of KOH and K salts). 
If the water solution be heated it begins to become 
turbid at 60 C. At 75 C. large flakes separate; 
the albumen is coagulated, and a faint odor of IPS 
noticed. The addition of HC1, H 2 S0 4 , HNO 3 causes 
the coagulation without heating ; the addition of 
KOH or NaOH prevents coagulation, even at boil- 
ing heat. 

Basic lead acetate, (HO)Pb.A 2 , forms a precipi- 
tate with albumen. The percentage composition of 
dry albumen is : C = 53.4, H = 7.0, N = 15.6, = 
22.4, S 1.6. The blood of all animals contains a 
(386) 



ALBUMEN AND ALBUMENOIDS. 387 

colorless substance which acts like the white of 
eggs, and a similar body is contained in the sap of 
all plants : they are known as blood albumen and 
vegetable albumen. What biologists call protoplasm 
is chemically not clistinguished from albumen, but 
protoplasm has life and albumen has not. To 
find the conditions under which ordinary albumen 
will change into protoplasm will be equivalent to 
finding the source of life itself. A very grand prob- 
lem, and one which I think possible of solution, 
though not probable. * 

All derivatives and homologues of albumen we 
call albumenoids. 

Haemoglobin, C = 53.8, H = 7.3, N = 16.1, S = 
0.5, Fe = 0.4, = 21.9. This body gives the red 
color to blood. Under the microscope a drop of 
blood reveals a colorless fluid in which spheroid 
red bodies float freely, together with pale bodies of 
the same shape. The first are known as the red 
blood corpuscles, the second as the white corpuscles 
or leucophytes. Diameter about 0.013 mm. The 
bulk of the red corpuscles is water and haemoglobin. 
Note the iron in the composition. The red color is 
due to this iron. Haemoglobin absorbs oxygen, 
nitric oxyd, carbon monoxyd, hydrogen cyanid. 

' The reason for the very fatal action of CO and HCN 
upon man is probably due to this property of the 

i haemoglobin. 

Haematin, L* 8 H 51 Fe*N* O 9 . This is a genuine 

!| chemical unit. Blue-black of color, insoluble in 
water, alcohol, ether. Soluble in solutions of KOH 



388 CHEMISTRY SIMPLIFIED. 

NaOH, NH 4 HO. Also in dil. H 2 S0 4 . The alka- 
line solution is olive green in thin column and red 
in thick column. Obtained from haemoglobin. 

Fibrin, C = 52.6, H == 7.0, N == 17.4, O = 21.8, 
S = 1.2. Fibrin is held in solution in the fresh blood. 
When blood is in contact with air for a short time 
it clots, becomes thick. Beating with a paddle sepa- 
rates from the blood a red, stringy, fine fibrous 
mass, which is fibrin mixed with haemoglobin. 
The clear liquid is named the serum of the blood, 
and contains the blood albumen and many other 
bodies besides the mineral salts. The muscles are 
chiefly modified fibrin, so called hyssin, creatinin, 
sarkin, xanthine, all albumenoids. 

Casein (cheese stuff), C = 53.6, H == 7.1, N == 15.7, 
22.6, 8 = 1.0. This body is found in the 
skimmed milk together with milk-sugar and salts. 
Casein is the chief nutriment in milk. It is well 
known that milk curdles and then has a sour re- 
action. The curds are composed of casein and 
water ; the water can be removed by pressing and 
drying. Casein turns into cheese by the action of 
ferments. 

Horn, hair, skin are all closely allied to albumen, 
although their chemical action is quite different, for 
these bodies are quite insoluble in water and in all 
agents except concentrated alkalies, which dissolve 
them and evolve NH 3 as other albuminoids. 



ALBUMEN AND ALBUMENOIDS. 389 

hair horn finger-nail wool 
C =49.8 50.7 50.2 49.8 
H = 6.4 6.7 6.8 7.0 

N =17.1 17.3 16.9 17.7 
+ 8 = 26.7 25.3 26.1 25.5 
Boiling water changes the skin into gelatine or glue. 
Silk is partly soluble in boiling water, which ex- 
tracts sericin, C 15 H 25 N 5 8 , and leaves fibroin, 

C 15 H 23 N 5()6 

Distillation of albumenoid substances. Animal 
charcoal. When albumenoid bodies, more particu- 
larly the hoofs and horns, and leather scraps of 
cattle are subjected to dry distillation, the succes- 
sion of phenomena and the products are in gen- 
eral similar to those which we observed in the dis- 
tillation of wood and coal, especially the latter. 
Yet the quality and quantity of the products are 
different. 

The distillation furnishes (1) a black residue 
animal charcoal ; (2) a watery ammoniacal liquid, 
and oils (not tar) ; (3) gases of exceedingly strong 
and disagreeable odor. Animal charcoal contains 
more or less of the original nitrogen according to 
the degree of the temperature. Much of the 
nitrogen goes over as NH 3 .00 2 (carbamid) and 
(NH 4 ) 2 C0 3 . (This used to be the chief source of 
ammonium salts, hence the expression salts of and 
spirits of hartshorn). 

All charcoal has the faculty of attracting coloring 
matter which may be either actually dissolved or 
only suspended in liquids ; but animal charcoal, and 



390 CHEMISTRY SIMPLIFIED. 

especially bone charcoal (bone-black), are more effi- 
cent than wood charcoal. The oil resulting from 
this work is known as the oil of Dippel, or also 
neat's foot oil much in use formerly as a lubricant 
for clocks and watches and other delicate mechan- 
ism. It does not turn rancid, nor change into resin- 
ous sticky substances as other oils do. 



CHAPTER XXV. 
ORIGIN OF CYANIDS. 

WHEN potash (pearlash) is liquefied in an iron 
crucible or pot at a bright red heat and animal 
charcoal (except bone-black) be added, the charcoal 
disappears amid turbulent evolution of gas. (In 
practice the proportions of potash and charcoal vary, 
perhaps 1 : 1 is a good average.) If then the fused 
mass be digested with water, or boiled with the 
latter in the kettle or iron pot, and then allowed to 
stand quietly, there will be found, after several days, 
a crop of yellow quadratic crystals and a mother 
liquor containing K 2 C0 3 ,K 2 S, and some other 
bodies. This liquor, after evaporating to dryness, 
can be used in the next operation with fresh potash. 
The crystals are of exceeding interest. In the drug 
trade they are known as yellow prussiate of potash. 
The German chemist Diesbach, of Berlin, was the 
first who discovered that this salt gives with certain 
salts of iron a beautiful blue precipitate known as 
prussian blue but kept his knowledge as a secret; the 
Englishman Woodward, in 1724, published the first 
account of its preparation. In 1752, the French- 
man Nacquer obtained the pure salt, the phlogisti- 
cated alkali, but only through the genius and labors 
of Scheele (1732), of Gay-Lussac and Porret (1814), 
(391) 



392 CHEMISTRY SIMPLIFIED. 

of Gmelin (1822), and lastly of Liebig, came to light 
the true nature of this remarkable substance, which 
chemists now call unanimously potassium ferrocya- 
nate and give to it the symbol K 4 (Fe(CN) 6 ). The 
symbol assumes the existence of a radical (Fe(CN) 6 ) 
of the valence four. Within this larger radical 
there are six units of the smaller radical (CN) = 
cyanogen. The larger radical is ferro-cyanogen, 
which some chemists write FeCy and therefore the 
yellow crystals are K 4 FeCy + 3H 2 0. One ,sees 
here the very positive iron become a part of a very 
negative complex radical, in such a way that from 
a solution of this salt the alkaline hydroxyds do not 
precipitate any iron hydroxyd, nor does H 2 S precip- 
itate any FeS when passed into the alkaline solu- 
tion. But for an understanding of this strange 
complex it will be necessary to break down the com- 
plex form in order to get at the fundamental unit 
cyanogen. 

Properties of potassium ferrocyanate. Commonly 
the crystals show a light lemon-yellow color ; color 
is sometimes orange. The crystals are very cleav- 
able parallel to the basal plane and the cleavage 
plates are pliable, elastic. The salt dissolves in 4 
parts of water at ordinary temperature, in 2 parts at 
boiling temperature. It loses its water of crystal- 
lization between 100 and 110 C. and becomes an 
opaque, chalk-like mass. At red heat it melts and 
decomposes with evolution of nitrogen gas, thus : 

K 4 (Fe(CN) 6 ) + red heat = 4K(CN) + 2C + Fe+2N. 



OEIGIN OF CYANIDS. 393 

The fused mass is grey. Water extracts a colorless 
solution of K(CN), potassium cyanid, leaving behind 
a black mixture of iron and carbon and iron carbid. 
Potassium cyanid, K(CN). C = 18.4, N = 21.5, 
K=60.1. It is a white crystalline body. Easily 
soluble in water. Insoluble in 95 percent, alcohol ; 
but in warm 50 per cent, alcohol it is fairly soluble. 
On cooling the solution will deposit isometric cubes 
or cubo-octohedrons similar to KC1 or NaCl. The 
salt itself as well as the solutions emit the strong and 
peculiar odor of bitter almonds, because the CO 2 of 
air decomposes the solution (and the solid salt in 
moist air also) thus : 

2K(CN) + H 2 + CO 2 = K 2 C0 3 + 2H(CN). 

The odor is due to H(GN) = hydrogen cyanid. The 
solution of K(CN) in water does not bear heating, 
and therefore cannot be concentrated by boiling as 
other salt solutions, because the salt breaks up thus : 

K(CX) + 2H 2 + water + heat = K(CHO 2 ) + 
NH 3 + water. 

That is, potassium cyanid breaks up into potassium 
formate and ammonia. This behavior should be 
well remembered. 

Preparation. Pulverize the yellow ferrocyanate 
coarsely. Heat in a flat, iron dish or pan to expel 
water of crystallization. The salt turns w r hite. 
Fill it into an iron crucible, which stands in a 
furnace, after admixing dry pearlash in the ratio 
of 3 parts of pearlash to 8 parts of the dehydrated 
ferrocyanate. Cover with an iron lid and heat grad- 



394 CHEMISTRY SIMPLIFIED. 

ually to yellow heat. The K 2 C0 3 is added in 
order to save all the cyanid, thus : 

2K 4 (Fe(CN) 6 ) + 2K 2 C0 3 + yellow heat = 

10K(CN) + 2K(CNO) + 2C0 2 + 2Fe. 
K(CNO) is potassium cyanate. The product is thus 
a mixture of 5 molecules potassium cyanid with 1 
molecule potassium cyanate. The cyanate is not 
harmful for any of the ordinary uses of the cyanid. 
In order to obtain pure KCN, the pearlash is left 
out. When the mass in the crucible fuses quietly, 
introduce a warm glass rod, and this rod, upon 
cooling, must be covered with a pure white film of 
the salts. Tap the crucible several times on the 
floor to cause a perfect settling of the iron particles 
and pour out into ingot moulds. 

Chemically pure KCN can only be obtained by 
passing H(CN) into a solution of KOH in alcohol, 
the liquid being kept cool. Then K(CN) separates 
in small crystals. Collecting these upon a filter 
they can be melted into solid cakes of desired shape 
and size. K(CN) is very poisonous. It is used to 
extract gold from the ores, because Au dissolves, 
forming a double cyanid, but only in presence of 
air thus : 

2Au + 4K(CN) + H 2 + = 2Au(CN).K(CN) + 

2KOH. 

A very dilute solution such as 0.2 per cent. KCN is 
just as efficient as a strong solution. Silver dis- 
solves similarly and all silver salts except Ag 2 S and 
even the latter slowly in presence of air. Hence the 



ORIGIN OF CYANIDS. 395 

use of KCN in cleaning silverware, in fixing photo- 
graphic negatives. K(CN) is used as a solvent in 
electroplating with silver, with gold, and other 
metals. It is used for separating nickel from cobalt. 
Hydrogen cyanid, prussic acid, H(CN), is at ordi- 
nary temperature a colorless liquid. Strong odor of 
bitter almonds or peach kernels. Boiling-point at 
26.5 C., hence exceedingly volatile. One drop upon 
a glass slide solidifies from the sinking of the tem- 
perature due to the rapid evaporation. Point of 
solidification lies at 15 C. Specific gravity = 
0.696. H(CN) barely reddens blue litmus. This 
substance is so very dangerous that it should only 
be handled by very expert persons. Mixes with 
water and with alcohol in all proportions. The 
water solution exposed to light decomposes into a 
brown solid and NH 3 , hence such solution should 
not be kept, but should be prepared whenever 
needed. The vapor of H(CN) burns with a purple 
flame. H(CN) is changed by concentrated HC1 or 
H 2 S0 4 into formic acid H(CH0 2 ) and ammonium 
salt thus : 

HCN + 2H 2 + HC1 H(CH0 2 ) + NH 4 C1. 

(Some water must be present). 

That (CN) is a monad and combines with one H 
can be shown by decomposing one volume of the 
vapor or gas over mercury by K, when J vol. of 
hydrogen results. The water solution of H(CN) 
dissolves oxyds and hydroxids, forming metallic 
cyanids : 



396 CHEMISTRY SIMPLIFIED. 

HgO + 2H(CN) = Hg(CN) 2 + IPO, 

Mercuric cyanid which is soluble in water. 

Preparation of H(CN). The reaction HC1 + 
K(CN) is not available, because the solution of 
K(CN) does not stand heating. (See above.) But 
the yellow prussiate is available for this purpose, 
with the following scheme : 

2K 4 (Fe(CN) 6 ) + 3H 2 S0 4 == 6H(CN) + 3K 2 S0 4 + 
K 2 (Fe 2 (CN) 6 ) a blue substance. 

Recipe. Bring into a short-neck flask 30 grams 
pulverized yellow prussiate and a cooled mixture of 
21 grams cone. H 2 S0 4 with 42 c.c. of water. Con- 
nect with Liebig's condenser and let the end of the 
condenser tube dip just under the distilled water 
(25 c.c.) in the receiver. Then distill. 

Cyanogen, C 2 N 2 . (Kuaneos = Cy.). This radical 
is at ordinary temperature a colorless gas of peculiar 
odor and very poisonous. The gas shows a sp.gr. 
of 1.806. It is inflammable and burns with purple 
flame. Under a pressure of 3 atmospheres it be- 
comes a mobile liquid which turns into a mass of 
crystals at -35 C. It is soluble in water and in 
alcohol. 

Preparation. We heat in a small retort, or in a 
glass tube, mercuric cyanid (see above), the latter 
breaking up : 

Hg(CN) 2 + heat = Hg + C 2 N 2 . 
Composition. We collect the gas over mercury ; 
add somewhat more than 2 volumes of and J vol- 
ume (H 2 +0) fulminating gas, and explode. We 



ORIGIN OF CYANIDS. 397 

introduce KOH to absorb CO 2 . Next we introduce 
hydrogen, 2 volumes, and explode after reading the 
volume. From the contraction we find the rem- 
nant of after first explosion (J contraction and f 
contraction for H consumed), and subtracting this 
from the remnant of N -f H we get at the vol. of N, 
and in the absorbed vol. of*C0 2 there is J vol. of C. 
And then we find that 1 vol. cyanogen gives 1 vol. 
C + 1 vol. N, hence cyanogen in the free state is 
(C 2 N 2 ) not (ON). It follows also that here is an 
exception to the law which we found previously. 
Here" one volume of an element uniting with one 
volume of another element yields two volumes of the 
combination. In cyanogen the two volumes give 
only one volume of the product. This is verified 
by the volume weight of the gas, for. 

1 volume of C weighs 1.072 grs. 

1 volume of N weighs 1.250 grs. 



1 volume of C 2 N 2 weighs 2.322 grs., 

>vhile the experiment gives 2.326 for one volume of 
cyanogen. Cyanogen combines with chlorine to 
form (CN)Cl, a terribly poisonous gas. It also com- 
bines with bromine. 

Sulfocyanogen, (CNS) 2 , forms colorless crystals. 

Hydrogen sulfocyanate, H(CNS), a colorless liquid 
of pungent odor like HC1 and strong acid reaction. 

Potassium sulfocyanate, K(CNS). Colorless crys- 
tals : easily soluble in w^ater and in alcohol. The 
solution of this salt gives with ferric salts a blood- 



398 CHEMISTRY SIMPLIFIED. 

red solution in presence of free acid. Very delicate 
reaction. 

Preparation. Fuse together KCN + S in a cru- 
cible, dissolve in water and crystallize. 

Potassium ferricyanate, red prussiate of potash, 
K^Fe^CN) 1 2 ). A beautiful salt. The crystals are 
of deep garnet-red color and dissolve very easily, 
with an intense yellow color, in water. The crystals 
contain no water of crystallization. 

It is prepared by acting upon the solution of 
potassium ferrocyanate with chlorine ; thus : 
2K 4 (Fe(CN) 6 ) + water + 2C1 = K^Fe^CN) 1 2 ) + 

2KC1 + water. 

We say that 2 molecules of tetravalent ferrocya- 
nogen have become polymerized have coalesced 
in one hexavalent radical, ferricyanoge7i,(Fe*(CNy^). 

In qualitative analysis potass, ferricyanate serves 

to reveal the presence of a ferrous salt inasmuch as 

they combine to an intensely blue compound, thus : 

K 6 (Fe 2 (CN) 12 j + 3FeS0 4 + free acid + water = 

Fe^Fe^CN) 1 2 ) + 3K 2 S0 4 + free acid. 

Fe 3 (Fe 2 (CN) 12 ) is known as a blue coloring 
material under the name of TurnbuWs blue. 

Potassium ferrocyanate gives with ferric salts a 
similar combination of equal intense blue color 
which is named prussian blue. The following equa- 
tion represents this relation : 

3K 4 (Fe(CN) 6 ) + 4FeCl 3 + free acid + water = 

Fe 4 (Fe(CN) 6 ) 8 , prussian blue + 12KC1 + 

free acid -|- water. 



ORIGIN OF CYANIDS. 399 

Of prussian blue as well as of TurnbulPs blue 
there is a water-soluble variet} 7 , which results when- 
ever an excess of the potassium ferro- or potassium 
ferricyanate is added to a ferric or ferrous salt. 
This soluble form is known as wash blue in the 
laundry business. 

Potassium cyanate, K(CNO). This salt results 
when K(CN) is kept- liquid in presence of air. 

K(CN) + = K(CNO) at red heat. 

This strong affinity for oxygen is the reason why 
K(CN) is a most excellent agent for deoxydation at 
high heat. It is much used in assaying and in 
blowpipe work thus : 

SnO 2 + 2K(CX) + red heat = Sn + 2K(CNO). 

CuO + K(CX) + red heat = Cu + K(CNO). 
The aqueous solution of potassium cyanate breaks 
up even at ordinary temperature ; when heated to 
boiling NH 3 + CO 2 escape and K 2 C0 3 remains in 
the liquid. 
2K(CNO) + 3H 2 + heat - K 2 CO 3 -f C0 2 -f 2NH 3 . 

Hydrogen cyanate can be made, but is exceedingly 
unstable. It has an odor somewhat like a mixture 
of SO 2 + HC 2 H 3 2 . It is very curious that if a 
solution of (NH*)(CXO), ammonium cyanate is 
evaporated, only water escapes, but the residue has 
all the properties of urea, (CH*N*0), the principle 
secretion in the animal and human urine. 

Cyanuric acid, H 3 (C 3 N 3 O 3 ) can be made in large 
colorless crystals. One recognizes that this is the 
formula of cyanic acid multiplied by 3. It results 



400 CHEMISTRY SIMPLIFIED. 

from the heating of dry urea above the boiling-point, 
when NH 3 escapes and cyanuric acid is left. 

Fulminic acid is not known in the free state. But 
we saw above that the analysis of the mercuric 
fulminate gives HgC 2 N 2 2 . Now this radical 
(C 2 N 2 2 ) is just the double of the radical in (CNO) 
cyanic acid. Hence we have here an intensely 
interesting polymerism or equal percentage-com- 
position for three totally different substances. 



CHAPTER XXVI. 
BONE-ASH AND PHOSPHORUS. 

THE animal skeleton is composed of bones. The 
bone again can be separated into a mineral part 
(not combustible), into gelatine (glue) and into fat. 
The fat may be extracted by any of its solvents 
(carbon disulfid, ether, chloroform, etc.) The gela- 
tine can be boiled out by water. If the bone after 
extraction is merely dried and bleached it becomes 
fit for conversion into useful and ornamental ob- 
jects (by the lathe and by the carving tool). If it 
be thrown into a hot furnace it will be converted 
into bone-ash. With the latter and its chemical 
nature, we shall now occupy ourselves. 

Bone-ash is infusible and somewhat luminous 
at a high temperature. It dissolves in HC1, in 
HNO 3 -|- aq., but not in H 2 S0 4 . There is usually 
a disengagement of CO 2 unless the burning of the 
bones had been done at very high heat. In the 
latter instance a small quantity of the ash will pro- 
duce a brown spot (alkaline reaction) when placed 
upon a strip of yellow turmeric paper. It acts thus 
like CaO. The solution in HC1 gives a white, gel- 
atinous precipitate when NH 4 (HO) is added; there- 
fore there must be an add present of as yet unknown 
properties, because the solution of calcite in HC1 
26 ( 401 ) 



402 CHEMISTRY SIMPLIFIED. 

or of CaSO 4 in HG1 does not precipitate with 
(NH 4 )HO. The presence of calcium is, however, 
made certain by the form of the minute crystals 
which are separated upon adding cone. H 2 S0 4 to 
the HC1 solution of the bone-ash. These crystals 
are identical in shape with the calcium sulfate or 
vitriol. 

But since we have learned that oxalic acid forms 
with calcium an oxalate which is not soluble in 
water and not soluble in dilute acetic acid, we can 
apply that knowledge right here to advantage. For 
we find the precipitate which is thrown down by 
NH 4 HO in an HC1 solution of the bone-ash to be 
quite soluble in acetic acid. Adding a solution of 
ammonium oxalate to the latter a bulky white pre- 
cipitate falls and thus calcium in large quantities is 
proved beyond any doubt. Let us designate the 
unknown acid as A x ; then we can write a prelimi- 
nary scheme for what we have thus far accomplished. 

Bone-ash = CaA x ; solution of bone-ash in 
(m + 2)HC1 = CaCl 2 + H 2 A X -f mHCl ; the pre- 
cipitate by NH 4 HO must be CaA\ 

The acetic solution will be again 

H 2 A x + mNH 4 Cl -f nNH 4 (C 2 H 3 2 ) -f 
qH.C 2 H 3 2 + Ca(C 2 H 3 2 ) 2 -f- H 2 -solution. 

To this solution we add ammonium oxalate 
(NH 4 ) 2 C 2 4 , and thus we get a precipitate and a 
liquid. The precipitate will be Ca(C 2 4 ), the liquid 
will contain H 2 A X -f NH 4 C1 -f NH 4 (C 2 H 3 2 ) + 
H.C 2 H 3 2 + (NH 4 ) 2 C 2 4 water. We filter and 



BONE-ASH AND PHOSPHORUS. 403 

evaporate to dry ness. Then we heat carefully over 
an open flame, causing the volatilization of NH 4 C1 
and of NH 4 (C 2 H 3 2 ); further mcrease of heat will 
eliminate the excess of (NH 4 ) 2 O and we will have, 
probably, H 2 A X , the unknown acid, or perhaps 
(NH 4 ) 2 A X ; provided that this unknown acid does not 
easily volatilize. We find fhat a remnant is left ; 
that this remnant imparts a green color to the flame, 
and that it dissolves in water, giving a colorless 
solution which shows a strong acid reaction. We 
also find that the remnant does volatilize at a red 
heat. Thus we have established that this body is 
probably an acid-forming, non-metallic, oxyd. It 
is not probable that any of the non-metallic elements 
of our acquaintance could produce such a residue, 
since their oxyds are very easily volatilized, or since 
they form hydrogen compounds which are quite 
volatile. In order to separate the element a treat- 
ment with strong deoxydizing bodies is indicated, to 
wit, potassium, sodium, hydrogen, carbon, marsh gas. 
Of these possible agents carbon is the only available. 
(Reasons below.) We make H 2 A X into a thick 
syrup by using H 2 S0 4 to precipitate the calcium 
instead of using NH 4 HO and (NH 4 ) 2 O, and then 
evaporating. Mix charcoal powder with it until a 
sticky mass results. Heat over open flame until 
quite dry, and then fill the black mass into a tube, F, 
Fig. 103, of hard infusible glass, which has been 
closed at one end. By placing the tube upon a 
brick (1) against a second brick (2) and using a 
Bunsen blowpipe on the closed end, we can bring 



404 



CHEMISTRY SIMPLIFIED. 



the tube to the required temperature. As the heat 
rises we begin to observe a peculiar odor at the 
mouth of the tube, and on approaching a taper a 
greenish flame develops, a white smoke rising into 
the air. At the same time wax -like drops con- 
dense in the forward part of the tube at (3). At 
length the flame burns more. and more with a pure 

FIG. 103. 




blue color (CO) and the action is complete. When 
the tube has become cold we cut off the forward 
part with a file stroke and a red-hot rod (glass or 
iron). The new substance is transparent or trans- 
lucent. Its color varies from pale yellow to bright 
red. (Probably 2 different substances ?) It is soft 
as wax. It emits a peculiar odor similar to that 
of ozone. A white fume arises from it steadily. It 
melts at 45 C., and begins at once to burn with a 
bright flame and evolution of white fumes. Under 
water it can be melted without danger of ignition. 
It dissolves somewhat in alcohol, more in fat oils. 
If such solution is rubbed over the hands or the face 
those parts will shine in a dark room with a pale 
green light. This property has been the justifica- 
tion for giving to this remarkable elementary body 



BONE- ASH AND PHOSPHORUS. 405 

the name phosphorus (phos = light ; phorus = car- 
rier). It would be more consistent to change the 
name tophosgen, and thus obtain a consonant series : 
Oxygen, hydrogen, nitrogen, chlorogen, brornogen, 
iodogen, fluogen, phosgen, and so forth. 

(1). Note. Brand was the first to obtain phos- 
phorus, in 1674, by distilling, in a clay retort, 
the residual mass from evaporated urine ; but that 
bones contain much more phosphorus than does 
urine, was only discovered 100 years later by 
Scheele. 

(2) Note. Experience has shown that a higher 
percentage of phosphorus can be obtained from bone- 
ash if only two-thirds of the calcium are removed by 
means of H 2 S0 4 , leaving soluble calcium phosphate 
to be separated by filtration, to be evaporated, mixed 
with coal and dried before distillation. This plan 
is followed in the match factories. 

There are three modifications of phosphorus. 

(1). Common, pale-colored, phosphorus which crys- 
tallizes in octahedrons has essentially the properties 
already given. Specific gravity = 1.83 at 10 C. 
Above 45 C., that is, in the liquid state, the specific 
gravity decreases considerably ; with the temperature 
at 100 C. it is 1.695; at 200 C. = 1 .603. At the boil- 
ing-point = 1.485. Phosphorus boils at 250 C. and 
distills over in an atmosphere of hydrogen. Kapid 
cooling of the vapor throws the phosphorus out in a 
fluffy, snow-white condition (flowers of phosphorus). 
But it is quite certain that slight volatilization goes 
on at ordinary temperature. To this volatilization 



406 CHEMISTRY SIMPLIFIED. 

is probably due the phosphorescence, the power to emit 
light in a dark room. Surrounded by oxygen alone 
there is no phosphorescence ; but the latter pheno- 
menon appears when the oxygen is diluted with 
nitrogen. Phosphorus ignites at 60 C. in air. 
Rubbing on a rough surface causes ignition 
(matches). Mixed with KC10 3 a very explosive 
substance results (lucifer matches). 

Phosphorus is poison to man and animals when 
brought into the stomach or esophagus. Every 
particle of the phosphorus causes an intense local 
inflammation of the membrane, hence great pain 
and shock, which result in death. 0.2 gram may 
be a fatal dose for an adult person. Emptying the 
stomach by emetics and the pump may save the life 
in some cases. The workmen in match factories are 
known to suffer from necrosis of the teeth, the 
gums and the jaw-bones themselves. Burns made 
by burning phosphorus on the fingers have even 
been fatal. Wash out such wounds with utmost 
haste with a dilute water solution of bleaching lime, 
or bleaching soda (crude Javelle). 

The best solvent for the active form of phosphorus 
is carbon disulfid. 

(#). Amorphous red phosphorus. Sunlight, espec- 
ially the violet portion of it, or heat plus pressure, 
or the electric current, changes the ordinary phos- 
phorus more or less rapidly into the amorphous 
modification. In the factories the change is brought 
about by keeping the yellow phosphorus for 10 
days at a steady temperature of 260 C. 



BONE- ASH AND PHOSPHORUS. 407 

The amorphous red phosphorus is not poisonous. 
It does not melt even at red heat but volatilizes. It 
is not soluble in CS 2 nor in KOH. It appears as 
a scarlet or as a purplish-red, pulverulent mass, 
sometimes brown-red. In bulk it shows sometimes 
a weak metallic luster, more often no luster at all. 
It has neither taste nor odor, does not show phos- 
phorescence. It ignites at 260 C. Lt forms with 
KC10 3 , with PbO 2 , and with MnO 2 , mixtures which 
ignite by blows or friction. It is the only phos- 
phorus now used in matches, or on the friction sur- 
faces of safety match boxes. 

(3). Black crystallized phosphorus. By heating 
red phosphorus in a vacuum to 447 C. it is ob- 
tained as a violet-black mass of conchoidal fracture, 
or by fusing together in a vacuum phosphorus and 
metallic lead. After cooling one finds long-stretched 
rhombohedrons, black in reflected light, red in 
transmitted light. This phosphorus has a specific 
gravity of 2.34. 

Atomic weight of phosphorus, P = 31. The de- 
terminations of the vapor density lead to 62. We 
assume therefore that the element in the free state 
is P 2 . According to the combinations into which 
phosphorus enters with the non-metals, it is trivalent 
and pentavalent like nitrogen. 

The oxyds of phosphorus are P 2 5 , P 2 O 3 . 

Phosphorus pemtoxyd, P 2 5 , a colorless, vitreous 
solid or colorless triclinic crystals. Dissolves in 
water. Is very hygroscopic (goes slowly into a 
syrup when standing in moist air), hence it is often 



408 CHEMISTRY SIMPLIFIED. 

used to dry gases. It has no odor, but a very sour 
taste. Is sometimes called anhydrous phosphoric 
acid. Volatilizes partly at 250 C. But when 
heated quickly it changes its nature by polymeriza- 
tion (aggregation of molecules) and is much less 
volatile. 

Preparation. By igniting phosphorus in a flask 
in a current of perfectly dry air. The product is a 
mass of minute snowy-white crystals. For larger 
quantities a tinned sheet-iron cylinder is substituted 
for the flask. 

Phosphoric acids. It was Graham who first de- 
monstrated that the pentoxyd can form 3 hydrates 
and that these hydrates possess very distinct proper- 
ties. We distinguish these hydrates thus : The tri- 
hydrate, 3H 2 O.P 2 5 , the dihydrate, 2H 2 O.P 2 5 
and the monohydrate, H 2 O.P 2 5 . We translate 
these hydrates into the radical expressions or hydro- 
gen acids thus : 

Trihydrate, 3H 2 O.P 2 5 = 2H 3 (P0 4 ) = 

orthophosphoric acid. 
Dihydrate, 2H 2 O.P 2 5 = H 4 (T 2 7 ) = 

pyrophosphoric acid. 
Monohydrate, H 2 O.P 2 5 = 2H(P0 3 ) = 

metaphosphoric acid. 

Orthophosphoric acid, H S (P0 4 ). Orthorhombic, 
colorless crystals, or a thick syrup of specific gravity 
= 1.88. Strong acid reaction ; easily soluble in 
water. Gives green coloration to a flame. 

Preparation. (I). By acting with UNO 3 (specific 



BONE-ASH AND PHOSPHORUS. 409 

gravity = 1.2) upon ordinary phosphorus in a glass 
retort, (1 phosphorus, 10 acid), at such a tempera- 
ture that lively action ensues, but not a violent one, 
(because explosions may set in). After all the 
phosphorus has disappeared heat to boiling and dis- 
till over about 7 parts of the HNO 3 . The distillate 
has a specific gravity of 1.1-1.14 and may be used 
for another operation by adding enough concen- 
trated acid to bring gravity up to 1.2. Pour the 
liquid from the retort into an evaporating dish 
and evaporate carefully to syrup, or until all HNO 3 
has been removed. Sometimes there occurs during 
this stage another disengagement of NO from the 
fact that some P 3 is still present. The tempera- 
ture may be brought to 188 C. but not higher, for 
pyro-phosphoric acid may form. By adding some 
alcohol the remainder of HNO 3 may be removed 
more easily. The syrup of H 3 (P0 4 ) is called glacial 
phosphoric acid. 

(2). By acting upon red amorphous phosphorus 
with concentrated HNO 3 . The oxydation is more 
rapid and can be carried on in a beaker glass. 

Orthophosphates. The orthophosphoric acid can 
form 3 series of salts as follows : 

Monads, Na 3 (P0 4 ), HNa 2 (P0 4 ), H 2 Na(P0 4 ). 
Diads, Ca 3 (P0 4 ) 2 , Ca 2 H 2 (PO 4 ) 2 , CaH 4 (P0 4 ) 2 . 
Triads, A1 3 (P0 4 ) 3 , A1 2 H 3 (P0 4 ) 3 , A1H 6 (P0 4 ) 3 . 

The radical (PO 4 ) is trivalent, hence Na 3 (P0 4 ) is 
a fully saturated combination and so is A1(P0 4 ), be- 
cause aluminum is trivalent. But in order to bring 



"410 CHEMISTRY SIMPLIFIED. 

out the partially saturated series (A1 2 H 3 ) and 
(A1H 6 ), we must treble the saturated molecule into 
A1 3 (P0 4 ) 3 . Any diad "metal will form orthophos- 
phates similar to calcium. For example, copper will 
make Cu 3 (P0 4 ) 2 , Cu 2 H 2 (P0 4 ) 2 , CuH 4 (P0 4 ) 2 . The 
three series are sometimes called basic, neutral, acid.^ 
Cu 3 (P0 4 ) 2 is basic copper orthophosphate. 

Cu 2 H 2 (P0 4 ) is neutral copper orthophosphate. 
CuH 4 (P0 4 )is acid copper orthophosphate. 

The orthophosphates of potassium, sodium, am- 
monium are all soluble in water and all can be 
crystallized. The most common of them, because 
most easily obtainable, is Na 2 H(P0 4 ) + 12H 2 in 
inonoclinic crystals, and H.NH 4 .Na(P0 4 ) + 4H 2 0, 
also inonoclinic crystals. The latter salt goes under 
the names : salt of phosphorus, and microcosmic salt. 
This salt fuses into a perfect glass and dissolves at 
red heat most of the metallic oxyds, giving with some 
of them transparent glasses of constant color. Hence 
we utilize this salt as a flux in blow-pipe analysis. 

Preparation of microcosmic salt. Dissolve 353 
grams of the crystals of Na 2 HP0 4 + 12H 2 and 
53.5 grams of NH 4 C1 (sal ammoniac) in 1700 c.c. of 
warm water, filter and evaporate until a film of 
crystals forms at the surface. Let stand for several 
days in a cool place. A large crop of the micro- 
cosmic salt will have been formed. Drain crystals 
from mother liquor. Dissolve again in water and 
crystallize, repeating the recrystallization twice. 
Then you will have crystals sufficiently free from 
NaCl to answer for blow-pipe work. Reaction : 



BONE- ASH AND PHOSPHORUS. 411 

Na 2 HP0 4 + water 4- NH 4 C1 = NH 4 .NaHP0 4 + 

water -f- NaCl. 

Nad remaining in the crystals causes the bead, 
after fusion, to become white and opaque. 

Insoluble orthophosphates. The neutral solutions 
of all the metals are precipitated by adding a solu- 
tion of any alkali phosphate* (K, Na, NH 4 ). These 
precipitates are soluble in dilute acids even acetic 
acid. Two of these precipitates are of special inter- 
est because by means of them we distinguish ortho- 
phosphoric acid from other acids. 

(1). Silver orthophosphate, Ag*(PO*), a yellow floc- 
culent precipitate. The solution must be neutral 
before AgNO 3 is added to the unknown. 

(#). Ammonium-magnesium orthophosphate,NH*.Mg- 
(PO 4 ), a colorless, granular or crystalline precipitate 
which forms when MgCl 2 or MgSO 4 solution is 
added to a slightly ammoniacal solution of an ortho- 
phosphate. 

The most delicate or sensitive reagent for ortho- 
phosphate is the so-called molybdic solution. This is 
a solution of (NH 4 ) 2 Mo0 4 ammonium molybdate 
in HNO 3 , specific gravity 1.2; the solution is 
pale yellow or colorless. Any metallic phosphate 
is first dissolved in a little HNO 3 , or any unknown 
substance is heated with HNO 3 , water added and 
after filtering 1 volume of the molybdic solution is 
added. The temperature of the liquid is brought 
to about 50 C., and the liquid shaken rapidly. A 
fine granular, citron-yellow precipitate falls if a 
phosphate be present. The precipitate is (NH 4 ) 2 - 



412 CHEMISTRY SIMPLIFIED. 

H(P0 4 ).10Mo0 3 + 1JH 2 = ammonium-hydrogen 
phosphopolymolybdate. 

Pyrophosphoric acid, H*(P*0 7 ), is not known in 
solid state, only known as an aqueous solution. 

Preparation. Heat the salt Na 2 H(P0 4 ) -j- 12aq. 
in a crucible until all the water is driven out and 
then to redness for a short time. Reaction : 

2Na 2 H(P0 4 ) + heat == Na 4 P 2 7 + H 2 0. 

Dissolve in water without heating. To solu- 
tion add PbA 2 (lead acetate) ; a white precipitate 
Pb 2 (P 2 7 ) falls. Filter and wash. Suspend the 
precipitate in water and pass H 2 S into the liquid ; 
then you obtain Pb 2 (P 2 7 ) -f 2H 2 S = 2PbS -f 
H 4 (P 4 7 ), which are separated by filtering. 

Properties. (1). When the acid is neutralized 
with NH 4 OH and AgNO 3 is added, a white floccu- 
lent precipitate falls (not yellow as with an ortho- 
phosphate). (2). MgCl 2 does not produce a precip- 
itate. 

When the precipitate MgNH 4 (P0 4 ) (see above) is 
ignited Mg 2 (P 2 7 ) magnesium pyrophosphate is 
left behind. A solution' of pyrophosphoric acid 
reverts into orthophosphoric acid by boiling for 
several hours. 

Metaphosphoric acid, H(P0 3 ). A colorless glassy 
substance. 

Preparation. (1) By dissolving P 2 5 in cold 
water. (2) By heating the syrup of H 3 P0 4 , thus 
H 3 P0 4 + heat = H 2 0-f H(P0 3 ). (3) By fusing 
the microcosmic salt at a red heat we get 



BONE- ASH AND PHOSPHORUS. 413 

Na(NH 4 )H(P0 4 ) -f heat = Na(P0 3 ) + NH 3 + H 2 
sodium metaphosphate + ammonia -f- water. The 
characteristics of metaphosphoric acid are as fol- 
lows : (a) the acid solution causes coagulation (curd- 
ling) in a water solution of albumen. (Neither 
ortho- nor pyrophosphoric acid coagulates the albu- 
men.) (b) When the solution is neutralized with 
NH 4 HO, AgNO 3 solution gives a white gela- 
tinous precipitate, (c) When a solution of Na(P0 3 ) 
is added to neutral salts of the metals, a precipitate 
forms at first, but dissolves on further addition of 
the metaphosphate. Some of the precipitates sepa- 
rate like tough resin, some separate as oily liquids. 

Phosphorus trioxyd, P 2 S . White snowy aggre- 
gates of small crystals often in the shape of trees 
or ferns. 

Preparation. Heat phosphorus in a tube until it 
ignites, and allow a very slow current of dry air to 
pass through the tube. The oxyd sublimes into a 
receiver. In the dark it remains unchanged. Sun- 
light brings red or orange colors. In warm oxygen 
it ignites and changes to P 2 5 . 

It smells like phosphorus. Some authors say it 
is poisonous, others say it is not ; I, myself, think it 
is poisonous. Very slightly soluble in water. 

Phosphorous acid, hydrogen phosphite, H*(PO S ). 
Crystalline-white mass or distinct crystals. Soluble 
in water. Sour taste. Is a strong deoxydixing 
agent. In salts of gold, silver, copper, mercury, the 
acid causes precipitation of the metal. 

It is a diatomic acid, that is to say, only two of 



414 CHEMISTRY SIMPLIFIED. 

the hydrogens can be replaced by a metal. There 
are therefore two series of phosphites, Na 2 H(P0 3 ) and 
NaH 2 .(P0 3 ). 

Preparation. (1). By action of dilute HNO 3 upon 
phosphorus. (2). By the action of oxalic acid upon 
phosphorus trichlorid. Thus : 
PC1 3 + 3H 2 .C 2 4 = H 3 P0 3 -f 3HC1 + 3C0 2 + SCO. 

Hypophosphorous acid, hydrogen hypophosphite, 
H*P0 2 . A colorless substance in large scales or 
leaves. Its solution in water is even more deoxydiz- 
ing than the preceding phosphorous acid. It is a 
monobasic acid. Only one of the three hydrogens 
can be replaced by a metal. Thus NaH 2 (PO 2 ) or still 
better Na(HP0 2 H) = sodium hypophosphite, or 
Ba(HP0 2 H) 2 = barium hypophosphite. The hypo- 
phosphites have been recommended as very active 
stimulants of the nerves and the brain (humbug). 

Preparation, 3KHO+4P+3H 2 = 3KH 2 P0 2 -h 
PH 3 . This means that phosphorus in presence of 
water and KHO will form potassium hypophosphite 
plus phosphine (PH 3 ). Ca(HO) 2 and Ba(HO) 2 plus 
P act similarly. 

COMBINATIONS OF PHOSPHORUS WITH CHLORINE. 

Phosphorus trichlorid, PCI 3 . Colorless liquid. 
Produces white fumes in moist air ; refracts the 
light strongly, smell, penetrating, and the vapor 
causes tears to flow. Boils at 76 C. 

When PCI 3 is poured into cold water it sinks to 
the bottom and collects like a heavy oil ; soon a re- 
action sets up between the water and the chlorid, 



BONE-ASH AND PHOSPHORUS. 415 

PCI 3 -f 3H 2 = H 3 .P0 3 + 3HC1, the result being a 
liquid containing phosphorous acid and hydrochloric 
acid. Such a solution answers as a deoxydizer. 

Preparation. Place in a retort some pieces of dried 
stick phosphorus (dry with blotting paper), the 
retort having been previously filled with CO 2 gas. 
In the tubulus fits a cork, and through this passes 
a glass tube down to the phosphorus. A receiver 
is tightly connected with the retort, and is well 
cooled. Fill now the retort with chlorine, and 
warm the retort until the phosphorus melts, when 
the action begins and PCI 3 distills over. 

Phosphorus pentachlorid, PCI 5 . A colorless solid. 
Peculiar odor, fumes at the air. With little water it 
decomposes into HC1 and POC1 3 . It is often used 
in synthetic laboratory work to put Cl into complex 
molecules. With sodium it gives 2NaCl -f PCI 8 , 
and the same with other metals. With much water 
it decomposes into phosphoric acid and HC1. 

PCI 5 -f- 4H 2 = 5HC1 + H 3 (P0 4 ), orthophosphoric 

acid. 

Preparation. By acting with excess of Cl upon 
PCI 3 . There are, of less importance, PBr 3 , PBr 5 , 
PI 3 , PI 5 , PF 5 . 

Phosphine, hydrogen phosphid, PH 3 . A gas of 
disagreeable odor, somewhat resembling that of 
garlic. In a dark room the gas gives out a pale 
light like phosphorus itself. It causes a taste on 
the^ tongue. Sunlight decomposes the gas into 
hydrogen and red amorphous phosphorus. The gas 



416 CHEMISTRY SIMPLIFIED. 

is poisonous because the blood absorbs it like 
H(CN). Air containing 0.25 per cent. PH 3 kills 
animals in 5-10 minutes. Phosphine ignites in air 
at 149 C.; the flame is white and yields white 
smoke. But sometimes the gas is self -igniting. This 
self-ignition is attributed to the admixture of an- 
other compound PH 2 , which latter forms only under 
specific conditions. When phosphine gas is passed 
into solutions of Ag, Hg, Cu, Pb, Bi, Au salts, the 
metals are thrown out ; or phosphids of the metals 
are formed. PH 3 in a solution of AgNO 3 + water 
causes first a yellow precipitate of Ag 3 P.3AgN0 3 (? 
doubtful composition), but black Ag 3 P results ulti- 
mately. 

Preparation. (1). Place 5-10 grams of stick phos- 
phorus into a 150 c.c. flask. Fill the flask with 
KOH solution (1:5) up to the stopper. The latter 
carries one evolution tube, bent so that it can be 
made to dip under water in a dish or beaker glass. 
(The flask is to be filled completely to avoid ex- 
plosion with air). On heating the flask the gas 
evolution will set in, and if the water in the dish be 
warm, each gas bubble will ignite as it breaks over 
the water, and will form a ring of smoke in the air. 
(2). Place the phosphorus in the flask as before, but 
fill the flask with an alcoholic solution of KOH. (70 
per cent, alcohol.) The gas will not ignite by itself. 
The reason for this is that the self-igniting PH 2 re- 
mains dissolved in the alcohol ; does not mix with 
the gas PH 3 . In both these actions the PH 3 is 
generated by the reaction 



BONE-ASH AND PHOSPHORUS. 417 

3KHO + 4P -f 3H 2 = PH 3 + 3KH 2 P0 2 . 
(3). Prepare Na 3 P by fusing together sodium and 
phosphorus. Or by fusing together 

3Na 2 C0 3 + Ca 3 (P0 4 ) 2 -f 8Mg= 2Na 3 P + 

3CaC0 3 + 8MgO. 

In either case you get Na 3 P s and if a drop of water 
touches Na 3 P then phosphine will be disengaged 
(noticed by strong odor), and NaHO will form : 

Na 3 P -f- 3H 2 = PH 3 + 3NaHO. 
Metallic magnesium can be carried much better 
than sodium because it does not oxydize so easily at 
ordinary temperature. Hence the last reaction is 
the one best adapted to test an unknown mineral 
for phosphorus, in the field, in the operation of blow- 
pipe analysis-. We call it the phosphine reaction. 
It is all done in a small ignition tube. 

Composition of PH Z . Phosphine breaks up read- 
ily at a red heat into P -f H. If 20 c.c. of phos- 
phine are collected over mercury in a eudiometer 
(see ammonia) and the spark is sent through it, 
complete dissociation results in from 6 to 10 minutes, 
when the volume has increased to 30 c.c. Phos- 
phorus covers the surface of the tube and the gas 
consists entirely of hydrogen. Now since the vol- 
ume of solid phosphorus is so small as to be 
negligible it follows that 20 c.c. of phosphine con- 
tain 30 c.c. of hydrogen and 10 c.c. of phosphorus 
gas. Hence PH 3 . 

Phosphonium, PH 4 , corresponds to ammonium, 
*> and is only known hypothetically. Because 
27 



418 CHEMISTRY SIMPLIFIED. 

PH 3 coriibines by simple addition with HC1, giving 
PH 4 Cl (colorless crystals below 20 C.). 

Liquid hydrogen phosphid, PH 2 . A colorless 
liquid, not soluble in water. In contact with air 
ignites instantaneously. Forms when Ca 3 P 2 is de- 
composed with H 2 and the resulting gas is carried 
through a U-tube standing in the freezing mixture. 
At the same time with the liquid PH 2 , condenses a 
solid substance which has probably the composition 
P 2 H. Phosphorus combines directly with all 
metals, yielding metallic phosphids. Of practical 
importance are the phosphids of iron (in the metal- 
lurgy of iron and steel) and tin phosphid, Sn 4 P, 
beautiful silver-white crystals (in the manufacture 
of phosphorbronze). 



APPENDIX. 



THE CHEMICAL ELEMENTS, THEIR SYMBOLS, EQUIVALENTS 
AND SPECIFIC GRAVITIES. 



Name. Symbol. 


Mass 
Unit 
Weight. 


Specific 
Gravity. 


Aluminium AI. 
Antimony ... . . Sb 


27.5 
122 


2.56 
6 70 


Arsenic A.S 


75 


5 70 


Barium i Ba. 
Bismuth, Bi 


137.0 
210 


4.00 
9 7 


Boron B. 
Bromine Br 


11.0 
80 


2.63 
5 54 


Cadmium j Cd. 
Caesium j Cs. 
Calcium . . . Ca 


112.0 
133.0 
40 


8.60 
1.88 
1 58 


Carbon ... j C 


12 


3 50 


Cerium 1 Ce. 
Chlorine Cl 


92.0 
35 5 


6.68 
2 45 


Chromium Cr. 
Cobalt ... Co 


52.5 

58 8 


6.81 

7 7 


Columbium I Cb 


184 8 


6 00 


Copper . . . Cu 


63 


8 96 


Didymium ... . Di 


96 


6 54 


Erbium . E. 


1126 





Fluorine ...... . > F. 


19.0 


1.32 


Gallium ; Ga. 


69.9 


5.9 


Glucinuin ' Gl 


9 5 


2 1 


Gold (Aurum) | Au. 
Hydrogen H. 
Indium In 


196.0 
1.0 

113 4 


19.3 
0.069 
7.4 


Iodine . . . . I 


127 


4 94 


Iridium Ir 


198*0 


21.15 




56.0 


7.79 




90 2 


11 37 


Lead (Plumbum) . Pb 


207 


11 44 


Lithium ..... . j Li 


7.0 


059 









(419) 



420 



APPENDIX. 



Name. Symbol. 


Atomic 
Weight. 


Specific 
Gravity. 


Magnesium . . Mg. 


24.0 
55.0 
200.0 
96.0 
58.8 
94.0 
14.0 
199.0 
16.0 
106.5 
31.0 
197.4 
39.0 
104.3 
85.4 
104.4 
79.5 
28.0 
108.0 
23.0 
87.6 
32.0 
1X2.0 
129.0 
204.0 
115.7 
118.0 
50.0 
184.0 
120.0 
51.3 
61.7 
65.0 
89.5 


1.75 
8.01 
13.59 
8.60 
8.60 
6.27 
0.972 
21.40 
1.105 
11.60 
1 83 
21.53 
0.865 
12.1 
1.52 
11.4 
4.78 
2.49 
10.5 
0.972 
254 
2.05 
1078 
6.02 
11.91 
7.8 
7.28 
4.3 
17.6 
18.4 
550 

7.14 
4.15 


Manganese ! Mn. 
Mercury (Hydrargyrum) . . j Hg. 
Molybdenum , Mb. 
Nickel Ni. 
Niobium . . ... Nb. 
Nitrogen N. 
Osmium Os. 
Oxygen O. 
Palladium . * Pd. 


Phosphorus . . .... P. 
Platinum | Pt. 
Potassium (Kalium) ... K. 
Rhodium Ro. 
Rubidium Rb. 
Ruthenium I Ru. 
Selenium l Se. 
Silicon Si. 
Silver (Argentum) . Ag 


Sodium (Natrium) Na. 
Strontium j Sr. 
Sulphur ' . S 


Tantalum Ta. 
Tellurium Te. 
Thallium Tl. 
Thorium Th. 
Tin (Stannum) j Sn. 
Titanium Ti. 
Tungsten (Wolfram) .... W. 
Uranium j U. 
Vanadium . .... . 1 V 


Yttrium. . . Y. 
Zinc ' . . . . j Zn. 
Zirconium Zr. 



TABLE FOR THE COMPARISON OF THE SCALES OF REAUMUR' S, 
CELSIUS'S, AND FAHRENHEIT'S THERMOMETERS. 



Keaumur. 


Celsius. 


Fahrenheit. 


Reaumur. 


Celsius. 


Fahrenheit. 


15 


18.75 


_ 


33 


+41.25 


+106.25 


14 


17.50 


+0.50 


34 


42.50 


108.50 


13 


16.25 


2.75 


35 


43.75 


110.75 


12 


1500 


5.00 


36 


45.00 


113.00 


11 


13.75 


7.25 


37 


46.25 


115.25 


10 


12.50 


9.50 


38 


47.50 


117.50 


9 


11 25 


11.75 


39 


48.75 


119.75 


8 


10.00 


14.00 


40 


50.00 


122:00 


7 


8.75 


16.25 


41 


51.25 


124.25 


6 


7.50 


18.50 


42 


52.50 


126.50 


5 


6.25 


20.75 


43 


53.7* 


128.75 


4 


5.00 


23.00 


44 


55.00 


131.00 


3 


3.75 


25.20 


45 


56.25 


133.25 


2 


2.50 


27.50 


46 


57.50 


135.50 


+1 


1.25 


29.75 


47 


58.75 


137.75 








32.00 


48 


60.00 


140.00 


1 


+ 1 25 


34.25 


49 


61.25 


142.25 


2 


2.50 


36.50 


50 


62.50 


144.50 


3 


3.75 


38.75 


51 


63.75 


146.75 


4 


5.00 


41.00 


52 


66.00 


149.00 


5 


625 


43.25 


5S 


66.25 


151 25 


6 


7.50 


45.50 


54 


67.50 


153.50 


7 


8.75 


47.75 


55 


68.75 


155.75 


8 


10.00 


50.00 


56 


70.00 


158.00 


9 


11.25 


52.22 


57 


71 25 


160.25 


10 


12.50 


54.59 


58 


72.50 


162.50 


11 


13.75 


56.75 


59 


73.75 


164.75 


12 


15.00 


59.00 


60 


75.00 


167.00 


13 


16.25 


61.25 


61 


76.25 


169.25 


14 


17.50 


63.50 


62 


77.50 


171.50 


15 


18.75 


65.75 


63 


78.75 


173.75 


16 


20.00 


68.00 


64 


80.00 


176.00 


17 


21.25 


70.25 


65 


81.25 


178 25 


18 


22.50 


72.50 


66 


82.50 


180.50 


19 


23.75 


74.75 


67 


83.75 


18275 


20 


25.00 


77.00 


68 


85.00 


185.00 


21 


26.25 


79.25 


69 


86.25 


187.25 


22 


27.50 


81.50 


70 


87.50 


189.50 


23 


28.75 


83-75 


71 


88.75 


191.75 


24 


30.00 


86.00 ! 


72 


90.00 


194.00 


25 


bl.25 


88.25 


73 


91.25 


196.25 


26 


32.50 


90.50 1 


74 


92.50 


198.50 


27 


33.75 


92.75 


75 


93.75 


200.75 


28 


35.00 


95.00 


76 


95.00 


203.00 


29 


36.25 


97.25 


77 


96.25 


205.25 


30 


37.50 


99.50 


78 


97.50 


207.50 


31 


38.75 


101.75 


79 


98.75 


209.75 


32 


40.00 


104.00 


80 


100.00 


212.00 















(421) 



422 APPENDIX. 

Rides for the Conversion of the Different Thermometer 
Degrees into each other. 

The thermometers referred to in the table are gradu- 
ated so that the range of temperature, between the 
freezing and boiling points of water, is divided by 
Fahrenheit's scale into 180 (from 32 to 212) by 
Celsius's into 100 (from to 100), and by that of 
Reaumur into 80 (from to 80) portions or degrees. 

The spaces occupied by a degree of each scale are 
consequently as 1, i and J respectively, or as 1, 1.8 
and 2.25; and the number of degrees denoting the same 
temperature, by the three scales, when reduced to a 
common point of departure by subtracting 32 from 
Fahrenheit's, are as 9, 5, and 4. Hence we derive the 
following equivalents : 

A degree of Fahrenheit is equal to 0.5 of Celsius's, 
or to 0.4 of Reaumur's; a degree of Celsius's is equal to 
1.8 of Fahrenheit's, or to 0.8 of Reaumur's; and a de- 
gree of Reaumur's is equal to 2.25 of Fahrenheit's, or 
to 1.25 of Celsius's. 

To convert degrees of Fahrenheit into Celsius's or 
Reaumur's, subtract 32 and multiply the remainder by 
f for Celsius's, or, f for Reaumur's. 

To convert degrees of Celsius's or Reaumur's into 
Fahrenheit's, multiply Celsius's by -f, or Reaumur's 
by f , as the case may be, and add 32 to the product. 



APPENDIX. 423 

TABLE OF THE LITER WEIGHTS OF THE GASES. 

Temp. C. and 760 Mm. Pressure. 

1 liter of air weighs . . . 1.29300 Gms. 

" CO. " 1.25078 " 

< CO 2 . " 1.96500 " 

0. " ........ 1.42910 " 

H. " 0.08988 " 

N. " . . . ._.. . 1.25070 " 

NO. " 1.34260 ' 

NO 2 . " 2.05440 " 

" N 2 O, " 1.96770 " 

" NH 3 . " 0.76170 " 

Cl. " 3.17240 " 

" HC1. " 1.62850 *' 

H 2 S. " 1.52100 ' 

" SO 2 . " 2.86150 " 

CH*. " 0.71570 u 

steam*" 0.58960 " 

" C a H J . 4i 1.16200 " 

" Br. " 7.14259 " 

1. " 11.27100 " 

S. " 2.84300 " 

P. 5.63180 " 

Hg. " 9.02100 " 

HI. " 5.71067 <c 

HBr. " 3.61607 " 

" C 2 N a . *' 2.32653 u 

* At 100 C. and 760 Mm. 

The values in the above table may be calculated from 
the relation between the molecular weight in grams of 
the substance and its liter weight. This relation may 
be expressed as an equation thus : 

weight of gram-molecule = congtant = 22 38j 
weight of a liter 

,., . , , weight of gram molecule, 
or liter weight = = ^ 



INDEX. 



ACETATE, 359 
Acid, 72, 124, 129 
abietinic, 379 
acetic, 278, 358 
carbolic, 282 
citric, 366 
cyanuric, 399 
formic, 305, 358 
fulminic, 400 
gallic, 368 
gluco-sulfuric, 343 
hydrobromic, 138 
hydrochloric, 108 
hydrofluoric, 148 
hydroiodic, 142 
hypophosphorous, 414 
lactic, 364 
malic, 366 

metaphosphoric, 412 
muriatic, 108 
nitric, 164 

orthophosphoric, 408 
oxalic, 361 
pan, 227 
phosphoric, 408 
phosphorous, 413 
picric, 282 
prussic, 395 
pyrogallic, 369 
pyroligneous, 276 
pyrophosphoric, 412 
sulfuric, 50, 52, 216 . 
tannic, 366 
tartaric, 364 

Air, weight of, 13 

Albumen, blood, 386 
vegetable, 387 

Albumenoids, 387 

Alcohol, 346, 348 
absolute, 349 



i Aldehyde, 354 

Alkali, 91 
; Alkaline reaction, 91, 187 

Alkaloids, 383 

Aluminum reactions, 246 
j Amalgam, 87 

Ammonia, 186. 190 

liquid, 200 
j Ammonium, 194 
| Amylum. 340 

Anilin, 321 

Anode, 26 

Anthracite, 308 
i Aqua fortis, 156 

regia, 156 
| Arabin, 345 
' Atom, 33 

| Atomic weights, 34, 126 
i Atropin, 384 

BAKING powders, 121 
Balsam. 378 
I Base, 72, 129 
Benzene, 337 
Bleaching, 104 

lime, 104 
Bone-ash, 401 
black, 390 
! Braise, 85 
Bromates, 139 
Bromine, 137 
Bromo seltzer, 139 
Brucin, 384 
Butane, 303 

CAFFEIN, 383 
Calcite, 64 

! Calcium reactions, 252 
sulfid, 241 
tartrate, 365 



(425) 



426 



INDEX. 



Calcspar, 64 
Caoutchouc, 380 
Caps, percussion, 356 
Carbamid, 389 
Carbon, 202, 257 

atomic weight of, 262 

dioxyd, 259 

disulfid, 254 

hydrates. 270 

monoxyd, 262 
Carbonates, 90 
Carboys, 113 
Casein, 388 
Cathode, 26 
Caustic lime, 70 

soda, 122 

Cellulose, 264, 270, 305 
Chamber acid, 227 
Charcoal, animal, 389 

making, 274 
Charmotte, 85 

Chemical elements, their sym- 
bols, equivalents, and specific 
gravities, 419, 420 
Chinin,384 
Chloral, 354 
Chlorates, 105, 135 
Chlorid, silver, 111 
Chlorine, 98, 104 
Chloroform, 353 
Clay, fire, 41 
Coal, bituminous, 308 

brown, 309 

cannel, 309, 311 

distillation of, 316 

hard, 308 

origin of, 312 

-tar, 320 
Cocaine, 385 
Coke, 317 
Collodion, 272 
Colophony, 379 
Compounds, 16 
Copper oxyd, 16, 47 

reactions, 250 
Copperas, 35 

action of, on leather, 36 
Covellite, 234 
Creatinin, 388 
Cyanates, 394, 399 
Cyanids, 393 



Cyanogen, 396 

DECREPITATION, 93 
Deoxydation, 17 
Dextrin, 341 
Diamond, 257 
Dichloroxyd, 134 
Dichroism", 336 
Dissociation, 325 

Dynamite, 375 
/ 

EBONITE, 382 
Electrodes, 26 

Electrolysis, 25 

Electrolyte, 26 

Elements. 16 

their symbols, equivalents, 
and specific gravities, 419, 
420 

Endothermic reaction, 330 

Etching. 149 

Ether, 352 

Ethylene, 324 

Eudiometer, 31 

Exothermic reaction, 330 

TjUTS, 371 

-T Fermentation, 199, 347 
Ferricyanates, 398 
Ferrocyanates, 392 
Fibrin, 388 
Fibroin, 389 
Fire-clay, 41 

Flash-point of an oil, 337 
Fluorescin, 336 
Fluorids, 148 
Fluorine, 144, 150 
Fluorite, 144, 150 

gas, 146 
Fluorspar, 144 
Flux, 145 
Formate, 358 
Fuchsin, 322 
Fuel-gas, 333 
Fulminate, 355 
Fulminating gas, 27 

riALENA, 181 

U Galvani, 125 

Gangue, 144 

Gas, analysis apparatus for, 285 



INDEX. 



427 



Gas, fulminating, 27 

generator, 101, 103 

natural, 337 

works, plan of, 326 
Gases, table of the liter weights 

of the, 423 
Gasoline, 337 
Gay-Lussac tower, 225 
Gelatine. 389 

blasting, 375 
Glass ink, 150 
Glover tower, 222 
Glucose. 343 
Glue, 389 
Gluten. 209, 339 
Glycerin, 374 

nitro-, 375 
Gold, atomic-weight, 131 

chlorids. 131 

reactions, 246 
Graphite, 257 
Green vitriol . 35, 36 
Gum arabic, 345 
Gun-cotton, 271 

powder, 166 
Gutta-percha, 380 

HAEMATIN, 387 
Haemoglobin, 387 
Hair. 388 
Heat, specific, 132 
Horn, 388 
Hydrates, of potassium, 79 

of sulfuric acid, 55 
Hydrogen. 25, 61 

chlorid. 107 

peroxyd, 34 

sulfate. 216 

sulfid, 234, 237, 253 
Hydrometer. 112 
Hydroxyd, 71 
Hydroxyl, 129 
Hypo, 243 
Hyposulfites, 243 
Hyssin, 388 

TOE, 19 

JL Infusorial earth, 375 

Ink, 36, 368 

lodates, 143 

lodids, 142 



Iodine, 139, 141 

and starch. 141 
lodoform, 354 
lodyrite, 144 
Iron, reactions of, 246 
j Isomerids, 303 

KELP, 122 
Kerosene, 337 
i Knee tube, 52 
Koenig generator, 101 

i T ACTOSE, 345 
, -L^ Laming 5 s mass, 328 
Laughing gas, 182 
Law of combination by volume, 

134 

Dulong and Petit, 133 
Lead, reactions of. 246 
Leather, 368 
Leblanc process, 119 
Levulose, 344 
Lignite, 309 
Lime, burnt, 70 
caustic, 70 
gas, 66 
hydroxyd, 71 
Limestone. 65 
Litmus. 15 
Lunge- Rohrmann plate column, 

226 
Lye, 77 

MAGNESIUM, 137 
Manganese chlorid, 100 

ore, 100 

Marsh gas, 295, 301 
series, 302 
Mass units, 33 
Mauvanilin. 321 
Mercury, fulminate, 355 

reactions of, 249 
Metals, 17 
i Methane, 295 
Methylanilin, 321 
Microcosmic salt, 410 
Molecular weight, 55, 126, 132 
Molybdic test for phosphates, 411 
Morphine, 209, 383 
; Mortar, 75 
| Mother liquor, 137 



4'28 



INDEX. 



NAPTHALINE, 320 
Nascent state, 186 
Natural gas, 337 
Nicotine, 209, 385 
Niter, 152, 209, 211 

plantation, 210 
Nitrates, 164 

test for, 178 
Nitrites, 179 
Nitro-benzol, 320 
cellulose, 271 
glycerin, 375 
Nitrogen, 154 

dioxyd, 171 

monoxyd. 176 

oxyds, 185 

weight of, 13, 159 
Nitrose, 223 
Nitrous fumes, 170 
Non-metals, 17 

OIL, neat's foot, 390 
ofDippel, 390 
vitriol, 230 
Oils, 370 
drying, 377 
essential, 371 
Olein, 377 
Orseille, 15 

Orthophosphates, 409, 411 
Oxybromids, 138 
-iodids, 143 
Oxyd, 16 

copper, 16, 47 
lead, 51 
Oxygen. 15, 31 
weight of, 13 

PALMITIN, 377 
Papyrine, 270 
Paraffin, 283, 337 
Parchment, 270 
Pearlash, 77 
Peat, 309 
Pentane, 304 
Periodate, 143 
Peroxyd of hydrogen, 34 

sulfur, 47, 49 
Petroleum, 335 
ether, 337 



Thenol, 282 
Phosphids, 418 
Phosphine, 415 

reaction, 417 
Phosphites, 414 
Phosphonium, 417 
Phosphorbronze, 418 
Phosphorus, black. 407 
pentachlorid, 415 
pentoxyd, 407 
red, 406 
trichlorid. 414 
trioxyd. 413 
yellow, 405 
Pitch, 380 

Plants, structure of, 265 
Platinum stills, 228 
Polysulfids, 241 
Potash, 77 

bulb. Liebig's, 267 

caustic, 79 
Potassium, 84 

chlorate. 105, 106 

hydroxyd, 79 

prussiate, red, 398 
yellow, 391 

reactions, 249 
Propane, 303 
Protoplasm, 209, 258 
Prussian blue, 391 
Putrefaction, 199 
Pyrite, 219 
Pyrogallol, 369 
Pyrolusite, 100 
Pyroxyline, 273 

AUININ, 384 

RADICAL, 124, 195 
Kectification, 350 
Kesin, 378 
Rock-oil, 335 

salt, 92 
Rosanilin. 322 
Eosin, 379 
Rubber, 380 

I Rules for the conversion of the 
different thermometer degrees 
I into each other, 422 



INDEX. 



429 



SAFETY lamp. Davy's, 300 
Sal ammoniac, 189, 197, 204 

soda, 121 
Salt, 72, 92, 129 
cake, 113 
gas, 94, 106 
of phosphorus, 410 
seignette, 364 
Saltpetre, 152 
Saponification. 377 
Sarkin, 388 
Sericin, 389 
Series, electrochemical. 125^ 

marsh gas, 302 
Silk, 389 
Silver chlorid, 111 

fulminate, 357 

reactions, 246 
Skin, 388 
Soap, 372, 377 

soft, 76 

Soda ash. 119, 121 
Sodium, 116 

carbonate, 121 

reactions, 249 
Solar oil, 281 
Soldering, 205 
Solvay process, 206 
Spar/65 

Specific heats, 132 
Spirits of niter, 155, 160 
salt, 94, 106 
Starch, 41, 340 
Stearin, 376 
Strychnine, 384 
Sugar, 342 

cane, 342 

fruit, 344 

grape, 343 

milk, 345 
Sulfid, 115 
Sulfocyanates, 397 
Sulfocyanogen, 397 
Sulfur, 13 

chlorid, 254 

oxyd, 16, 17, 52, 59 

peroxyd. 46, 49 

test for, 40 
Superoxyd, 117 



TABLE for the comparison of 
the scales of Reau- 
mur's, Celsius's and 
Fahrenheit's t h e r - 
mometers, 421 
of the liter weights of the 

gases, 423 
iTaflow,376 
: Tannin, 36. 366 
\ Tar, coal, 320 
Tartar emetic, 365 
Theobromin, 383 
, Thermometers, rules for the con- 
version of the 
different degrees 
of, into each 
other. 422 
table for the com- 
parison of the 
scales of Reau- 
mur's, Celsius's, 
and Fahrenheit's, 
421 

Thiosulfates. 243 
Tin, reactions, 246 
Toluidin, 323 
Turpentine, 378 

TTREA, 199, 383 

VALENCE, 125 
Varec, 122 
Vaseline, 337 
Vermilion. 234 
Vinegar, 15. 360 
Vitriol, calcium, 73 

copper, 46 

green, 35, 36 

hydrogen. 129 

iron, 54, 58 

lead, 51 

oil of, 40, 43, 50, 230 

silver, 49, 54 

zinc, 54 

Volume weights, 126 
Vulcanizing, 382 



w 



ATER, 31 
-gas, 331 



430 



INDEX. 



Water, hard, 74 

properties, 19 
Weights, atomic, 34, 126 

molecular, 55, 126 

volume. 126 
Wood distillation, 274 

gases, 285 

tar, 277, 279 



WooL 389 

VANTHINE, 388 
A. 



, reactions, 246 



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the Processes Dependent on the Ductility of the Metals ; Soldering; 
and the most Improved Processes and Tools employed by Metal* 
Workers. With the Application of the Art of Electro-Metallurgy to 
Manufacturing Processes; collected from Original Sources, and from 
the works of Holtzapffel, Bergeron, Leupold, Piumier, Napier, 
ScorTern, Clay, Fairbairn and others. By OLIVER BYRNE. A new, 
revised and improved edition, to which is added an Appendix, con- 
taining The Manufacture of Russian Sheet- Iron. By JOHN PERCY, 
M. D., F. R. S. The Manufacture of Malleable Iron Castings, and 
Improvements in Bessemer Steel. By A. A. FESQUET, Chemist and 
Engineer. With over Six Hundred Engravings, Illustrating every 
Branch of the Subject. 8vo. . -^' -. .... $5.00 

BYRNE. The Practical Model Calculator: 

For the Engineer, Mechanic, Manufacturer of Engine Work, Naval 
Architect, Miner and Millwright. By OLIVER BYRNE. 8vo., nearly 
too pages (Scarce.) 

CABINET MAKER'S ALBUM OF FURNITURE; 

Comprising a Collection of Designs for various Styles of Fumitnrcu 
Illustrated by Forty-eight Large and Beautifully Engrav-d Plates. 
Oblong, 8vo. . . . . .-.-.. $1.50 

CALLINGHAM. Sign Writing and Glass Embossing: 

A Complete Practical Illustrated Manual of the Art. By JAMES 
CALLINGHAM. To which are added Numerous Alphabets and the 
Art of Letter Painting Made Easy. By JAMES C. BADENOCH. 258 

pages, ismo . . . 11.50 

"AMPIN. A Practical Treatise on Mechanical Engineering: 
Comprising Metallurgy, Moulding, Casting, Forging, Tools, Work, 
shop Machinery, Mechanical Manipulation, Manufacture of Stean> 
Engines, etc. With an Appendix on the Analysis of Iron and Iron 
Ores. By FPANCIS CAMPIN, C. E. To which are added, Observations 
on the Construction of Steam Boilers, and Remarks upon Furnaces 
used for Smoke Prevention ; with a Chapter on Explosions. By R, 
ARMSTRONG, C. E., and JOHN BOURNE. (Scarce.) 



HENRY CAREY BAIRD & CG.'S CATALOGUE. 



CAREY. A Memoir of Henry C. Carey. 
By DR. WM. ELDER. With a portrait. 8vo., cloth . . 75 

CAREY. The Works of Henry C. Carey : 

Harmony of Interests : Agricultural, Manufacturing and Commer 

cial. 8vo. . $\.25 

Manual of Social Science. Condensed from Carey's " Principles 
of Social Science." By KATE McKEAN. I vol. I2mo. . #2.00 
Miscellaneous Works. With a Portrait. 2 vols. 8vo. $1000 

Past, Present and Future. 8vo $2.50 

Principles of Social Science. 3 volumes, 8vo. . . #10.00 
The Slave-Trade, Domestic and Foreign; Why it Exists, and 
How it may be Extinguished (1853). 8vo. . . , $2.00 
The Unity of Law : As Exhibited in the Relations of Physical, 
Social, Mental and Moral Science (1872). 8vo. . . $2.50 

CLARK. Tramways, their Construction and Working : 

Embracing a Comprehensive History of the System. With an ex- 
haustive analysis of the various modes of traction, including horse- 
power, steam, heated water and compressed air; a description of the 
varieties of Rolling stock, and ample details of cost and working ex- 
penses. By D. KINNEAR CLARK. Illustrated by over 200 wood 
engravings, and thirteen folding plates. I vol. 8vo. . $5.00 

COLBURN. The Locomotive Engine : 

Including a Description of its Structure, Rules for Estimating its 
Capabilities, and Practical Observations on its Construction and Man- 
agement. By ZERAH COLBURN. Illustrated. I2mo. . $1.00 

COLLENS. The Eden of Labor; or, the Christian Utopia. 
By T. WHARTON COLLENS, author of " Humanics," "The Historj 
of Charity," etc. I2mo. Paper cover, $1.00; Cloth . #1.25 

COOLEY. A Complete Practical Treatise on Perfumery : 
Being a Hand-book of Perfumes, Cosmetics and other Toilet Article! 
With a Comprehensive Collection of Formulae. By ARNOLD ' 
COOLEY. i2mo $1.50 

COOPER. A Treatise on the use of Belting for t\e Trans- 
mission of Power. 

With numerous illustrations of approved and actual methods of ar- 
ranging Main Driving and Quarter Twist Belts, and of Belt Fasten 
ings. Examples and Rules in great number for exhibiting and cal- 
culating the size and driving power of Belts. Plain, Particular and 
Practical Directions for the Treatment, Care and Manigement o r 
Belts. Descriptions of many varieties of Beltings, together with 
chapters on the Transmission of Power by Ropes; by Iron and 
Wood Frictional Gearing ; on the Strength of Belting Leather ; and 
on the Experimental Investigations of Morin, Briggs, and others. B 
JOHN H. COOPER, M. E. 8vo #3.50 

CRAIK. The Practical American Millwright and M^ler. 
By DAVID CRAIK, Millwright. Illustrated by numerous wood en~ 
gtavings and two folding plates. 8vo. ... . . (Scarce.) 



HENRY CAREY BAIRD & CO.'S CATALOGUE. 9 

CROSS. The Cotton Yarn Spinner : 

Showing how the Preparation should be arranged for Different 
Counts of Yarns by a System more uniform than has hitherto been 
practiced; by having a .Standard Schedule from which we make all 
our Changes. By RICHARD CROSS. 122 pp. I2mo. . 75 

CRISTIANI. A Technical Treatise on Soap and Candles: 
With a Glance at the Industry of Fats and Oils. By R. S. CRIS- 
TIANI, Chemist. Author of " Perfumery and Kindred Arts." Illus- 
trated by 176 engravings. 581 pages, 8vo. $15.00 

COURTNEY. The Boiler Maker's Assistant in Drawing, 
Templating, and Calculating Boiler Work and Tank 
Work, etc. 

Revised by D. K. CLARK. 102 ilk, Fifth edition. . 80 

COURTNEY. The Boiler Maker's Ready Reckoner: 

With Examples of Practical Geometry and Templating. Revised by 
D. K. CLARK, C. E. 37 illustrations. Fifth edition. $1.60 

DAVIDSON. A Practical Manual of House Painting, Grain- 
ing, Marbling, and Sign- Writing: 

Containing full information on the processes of House Painting ic 
Oil and Distemper, the Formation of Letters and Practice of Sign- 
Writing, the Principles of Decorative Art, a Course of Elementary 
Drawing for House Painters, Writers, etc., and a Collection of Useful 
Receipts. With nine colored illustrations of Woods and Marbles, 
and numerous wood engravings. By ELLIS A. DAVIDSON. i2mo. 

$2.00 

DAVIES. A Treatise on Earthy and Other Minerals and 

Mining: 

By D. C. DAVIES, F. G. S., Mining Engineer, etc. Illustrated by 
76 Engravings. I2mo. - $5.00 

DAVIES. A Treatise on Metalliferous Minerals and Mining: 
By D. C. DAVIES, F. G. S , Mining Engineer, Examiner of Mines, 
Quarries and Collieries. Illustrated by 148 engravings of Geological 
Formations, Mining Operations and Machinery, drawn from the 
practice of all parts of the world. Fifth Edition, thoroughly Revised 
and much Enlarged by his son, E. Henry Davies. I2mo., 524 
pages . $5.00 

DIETERICHS. A Treatise on Friction, Lubrication, Oils 

and Fats : 

The Manufacture of Lubricating Oils, Paint Oils, and of Grease, and 
the Testing of Oils. By E. F. DIETERICHS, Member of the Franklin 
Institute; Member National Association of Stationary Engineers; 
In ventor of Dieterichs' Valve-Oleum Lubricating Oik. I2mo. (1906.) 
A practical book by a practical man. . . . . $1.2$ 

DAVIS. A Practical Treatise on the Manufacture of Brick, 

Tiles and Terra-Cotta : 

Including Stiff Clay, Dry Clay, Hand Made, Pressed or Front, and 
Roadway Paving Brick, Enamelled Brick, with Glazes and Colors, 
Fire Brick and 'Blocks, Silica Brick, Carbon Brick, Glass Pols. R* 



jo HENRY CAREY BAIRD & CO.'S CATALOGlJe,. 

torts, Architectural Terra-Cotta, Sewer Pipe, Drain Tile, Glazed and 
Unglazed Roofing Tile, Art Tile, Mosaics, and Imitation of Intarsia 
or Inlaid Surfaces. Comprising every product of Clay employed in 
Architecture, Engineering, and the Blast Furnace. With a Detailed 
Description of the Different Clays employed, the Most Modern 
Machinery, Tools, and Kilns used, and the Processes for Handling, 
Disintegrating, Tempering, and Moulding the Clay into Shape, Dry- 
ing, Setting, and Burning. By Charles Thomas Davis. Third Edi- 
tion. .Revised and in great part rewritten. Illustrated by 261 

engravings. 662 pages $20.00 

DAVIS. A Treatise on Steam-Boiler Incrustation and Meth- 
ods for Preventing Corrosion and the Formation of Scale: 
By CHARLES T. DAVIS. Illustrated by 65 engravings. 8vo. 
DAVIS. The Manufacture of Paper : 

Being a Description of the various Processes for the Fabrication, 
Coloring and Finishing of every kind of Paper, Including the Dif- 
ferent Raw Materials and the Methods for Determining their Values, 
the Tools, Machines and Practical Details connected with an intelli- 
gent and a profitable prosecution of the art, with special reference to 
the best American Practice. To which are added a History of Pa- 
per, complete Lists of Paper-Making Materials, List of American 
Machines, Tools and Processes used in treating the Raw Materials, 
and in Making, Coloring and Finishing Paper. By CHARLES T. 
DAVIS. Illustrated by 156 engravings. 608 pages, 8vo. $6.00 
DAVIS. The Manufacture of Leather: 

Being a Description of all the Processes for the Tanning and Tawing 
with Bark, Extracts, Chrome and all Modern Tannages in General 
Use, and the Currying, Finishing and Dyeing of Every Kind of Leather; 
Including the Various Raw Materials, the Tools, Machines, and all 
Details of Importance Connected with an Intelligent and Profitable 
Prosecution of the Art, with Special Reference to the Best American 
Practice. To which are added Lists of American Patents (1884-1897) 
for Materials, Processes, Tools and Machines for Tanning,, Currying, 
etc. By CHARLES THOMAS DAVIS. Second Edition, Revised,' and 
in great part Rewritten. Illustrated by 147 engravings and 14 Sam- 
ples oi Quebracho Tanned and Aniline Dyed Leathers. 8vo, cloth, 

712 pages. Price $12.1:0 

DAWIDOWSKY BRANNT. A Practical Treatise on the 
Raw Materials and Fabrication of Glue, Gelatine, Gelatine 
Veneers and Foils, Isinglass, Cements, Pastes, Mucilac-es 
etc.: 

Eased upon Actual Experience. By F. DAWIDOWSKY, Technical 
Chemist. Translated from the German, with extensive addition^, 
including a description of the most Recent American Processes, by 
WILLIAM T. BRANNT. 2d revised edition, 350 pages. (1905.) 
Price .... 3., o 

DE GRAFF. The Geometrical Stair-Builders* Guide : ' 

Being a Plain Practical System of Hand-Railing, embracing all it- 
necessary Details, and Geometrically Illustrated by twenty-two Ste^ 
Engravings; together with the use of the most approved pnncipi" 
of Practical Geometry By SIMON DE GRAFF, Architect 



HENRY CAREY BAIRD & CO.'S CATALOGUE. il 

DE KONINCK DIETZ. A Practical Manual of Chemical 

Analysis and Assaying : 

Asapplied to the Manufacture of Iron from its Ores, and to Cast Iroa, 
Wrought Iron, and Steel, as found in Commerce. By L. L. DB 
KONINCK, Dr. Sc., and E. DIETZ, Engineer. Edited with Notes, by 
ROBERT MALLET, F. R. S., F. S. G., M. I. C. E., etc. America* 
Edition, Edited with Notes and an Appendix on Iron Ores, by A. A, 
FESQUET, Chemist and Engineer. I2mo. . . . Ji.oo 

DUNCAN. Practical Surveyor's Guide: 

Containing the necessary information to make any person of comj 
mon capacity, a finished land surveyor without the aid of a teacher 
By ANDREW DUNCAN. Revised. 72 engravings, 214 pp. I2mo. $1.50 

DUPLAIS. A Treatise on the Manufacture and Distillation 

of Alcoholic Liquors : 

Comprising Accurate and Complete Details in Regan! to Alcohol 
from Wine, Molasses, Beets, Grain, Rice, Potatoes, Sorghum, Aspho 
del, Fruits, etc. ; with the Distillation and Rectification of Brandy 
Whiskey, Rum, Gin, Swiss Absinthe, etc., the Prepar?tion of Aro- 
matic Waters, Volatile Oils or Essences, Sugars, Syrups, Aromatic 
Tinctures, Liqueurs, Cordial Wines, Effervescing Wines, etc., tbt 
Ageing of Brandy and the improvement of Spirits, with Copious 
Directions and Tables for Testing and Reducing Spirituous Liquors, 
etc,, etc. Translated and Edited from the French of MM. DUPLAIS, 
By M. McKENNiE, M. D. Illustrated 741 pp. 8vo. 15.00 

DYER AND COLOR-MAKER'S COMPANION : 

Containing upwards of two hundred Receipts for making Colors, on 
the most approved principles, for all the various styles and fabrics novr 
in evistence ; with the Scouring Process, and plain Directions for 
Preparing, Washing-off, and Finishing the Goods. I2mo. $i OO 

EIDHERR. The Techno-Chemical Guide to Distillation: 
A Hancl-Book for the Manufacture of Alcohol and Alcoholic Liquors, 
including the Preparation of Malt and Compressed Yeast. Edited 
from the German of Ed. Eidherr. 

EDWARDS. A Catechism of the Marine Steam-Engine, 
For the use of Engineers, Firemen, and Mechanics. A Practical 
Work for Practical Men. By EMORY EDWARDS, Mechanical Engi- 
neer. Illustrated by sixty three Engravings ; including examples of 
the most modern Engines. Third edition, thoroughly revised, with 
much additional matter. 12 mo. 414 pages . ^200 

EDWARDS. Modern American Loccmotive Engines, 
Their Design, Construction and Management. By EMORY EDWARDS* 
Illustrated I2mo $2.00 

EDWARDS. The American Steam Engineer: 
Theoretical and Practical, with examples of the latent and most ap- 
proved American practice in the design and construction of Steam 
Engines and Boilers. For the use of engineers, machinists, boiler- 
umkers, and engineering students. By EMORY EDWARDS. Fully 
illustrated, 419 pages. I2mo. - ... $2.00 



12 HENRY CAREY BAIRD & CO.'S CATALOGUE. 

EDWARDS. Modern American Marine Engines, Boilers, and 

Screw Propellers, 

Their Design and Construction. Showing the Present Practice ot 
the most Eminent Engineers and Marine Engine Buildeis in the 
United States. Illustrated by 30 large and elaborate plates. 410. $3.00 
EDWARDS. The Practical Steam Engineer's Guide 
In the Design, Construction, and Management of American Stationary, 
Portable, and Steam Fire- Engines, Steam Pumps, Boilers. Injector^ 
Governors, Indicators, Pistons and Rings, Safety Valves and Steam 
Gauges. For the use of Engineers, Firemen, and Steam Users. By 
EMORY EDWARDS. Illustrated by 119 engravings. A2o pages'. 
I2ino. .......... $2.OO 

EISSLER. The Metallurgy of Silver : 

A Practical Treatise on the Amalgamation, Roasting, and Lixiviation 
of Silver Ores, including the Assaying, Melting, and Refining of 
Silver Bullion. By M. EISSLER. 124 Illustrations. 336 pp. 

I2mo #4-25 

ELDER. Conversations on the Principal Subjects of Political 

Economy. 

By DR. WILLIAM ELDER. 8vo. ... . 2.00 

ELDER. Questions of the Day, 

Economic and Social. By DR. WILLIAM ELDER. 8vo. . $3.00 
ERNI AND BROWN. Mineralogy Simplified. 

Easy Methods of Identifying Minerals, including Ores, by Means of 
the Blow-pipe, by Flame Reactions, by Humid Chemical Analysis, 
and by Physical Tests. By HENRI ERNI, A. M., M. D. Third Edi- 
tion, revised, re-arranged and with the addition of entirely new matter, 
including Tables for the Determination of Minerals by Chemical and 
Pyrognostic Characters, and by Physical Characters. By AMOS P. 
BROWN, E. M., Ph. D. 350 pp., illustrated by 96 engravings, pocket- 
book form, full flexible morocco, gilt edges . . . $2.50 
FAIRBAIRN. -The Principles of Mechanism and Machinery 

of Transmission : 

Comprising the Principles of Mechanism, Wheels, and Pulleys, 
Strength and Proportion of Shafts, Coupling of Shafts, and Engag- 
ing and Disengaging Gear. By SIR WILLIAM FAIRBAIRN, Bart. 
C. E. Beautifully illustrated by over 150 wood-cuts. In one 

volume, I2mo $2.00 

FLEMING. Narrow Gauge Railways in America : 

A Sketch of their Rise, Progress, and Success. Valuable Statistics 
as to Grades, Curves, Weight of Rail, Locomotives, Cars, etc. By 

HOWARD FLEMING. Illustrated, 8vo $1.00 

FORSYTH. Book of Designs for Headstones, Mural, and 

other Monuments : 

Containing 78 Designs. By JAMES FORSYTH, With an Introduction 
by CHARLES BOUTELL, M. A. 410., cloth . . . #3.50 
FRIEDBERG. Utilization of Bones by Chemical Means- 
especially the Modes of Obtaining Fat, Glue, Manures. 
Phosphorus and Phosphates. 
Illustrated. 8vo. (In preparation.) 



HENRY CAREY BAIRD & CO.'S CATALOGUE. 13 



FRANKEL HUTTER. A Practical Treatise on the Manu- 
facture of Starch, Glucose, Starch-Sugar, and Dextrine: 
Based on the German of LADISLAUS VON WAGNER, Professor in the 
Royal Technical High School, Buda-Pest, Hungary, and other 
authorities. By JULIUS FRANKEL, Graduate of the Polytechnic 
School of Hanover. Edited by ROBERT HUTTER, Chemist, Practical 
Manufacturer of Starch-Sugar. Illustrated by 5$ engravings, cover- 
ing every branch of the subject, including examples of the most 
Recent and Best American Machinery. 8vo., 344 pp. $6.00 

GARDNER. The Painter's Encyclopaedia: 
Containing Definitions of all Important Words in the Art of Plain 
and Artistic Painting, with Details of Practice in Coach, Carriage, 
Railway Car, House, Sign, and Ornamental Painting, including 
Graining, Marbling, Staining, Varnishing, Polishing, Lettering, 
Stenciling, Gilding, Bronzing, etc. By FRANKLIN B. GARDNER. 
158 Illustrations. I2mo. 427 pp. . . . ;s ,. i . Jte.oC 

GARDNER. Everybody's Paint Book: 

A Complete Guide to the Art of Outdoor and Indoor Painting. 38 
illustrations. L2mo, 183 pp. . . . . , . . $l.oo 

GEE. The Jeweller's Assistant in the Art of Working in 

Gold: 
A Practical Treatise for Masters and Workmen. I2mo. ; $3.00 

GEE. The Goldsmith's Handbook : 

Containing full instructions for the Alloying and Working of Gold, 
including the Art of Alloying, Melting, Reducing, Coloring, Col- 
lecting, and Refining; the Processes of Manipulation, Recovery of 
Waste; Chemical and Physical Properties of Gold; with a New 
System of Mixing its Alloys; Solders, Enamels, and other Useful 
Rules and Recipes. By GEORGE E. GEE. I2mo. . . $1.2$ 

GEE. The Silversmith's Handbook : 

Containing full instructions for the Alloying and Working of Silver, 
including the different modes of Refining and Melting the Metal; its 
Solders ; the Preparation of Imitation Alloys ; Methods of Manipula- 
tion ; Prevention of Waste ; Instructions for Improving and Finishing 
the Surface of the Work ; together with other Useful Information and 
Memoranda. By GEORGE E. GEE. Illustrated. I2mo. $1.25 

GOTHIC ALBUM FOR CABINET-MAKERS: 

Designs for Gothic Furniture. Twenty-three plates. Oblong $1-5 

GRANT. A Handbook on the Teeth of Gears : 
Their Curves, Properties, and Practical Construction. By GEORGE 
B. GRANT. Illustrated. Third Edition, enlarged. 8vo. $100 

GREENWOOD. Steel and Iron: 

Comprising the Practice and Theory of the Several Methods Pur- 
sued in their Manufacture, and of their Treatment in the Rolling. 
Mills, the Forge, and the Foundry. By WILLIAM HENRY GREEN- 
WOOD, F. C. S. With 97 Diagrams, 536 pages. I2mo. $1.75 



i 4 HENRY CAREY BAIRD & CO.'S CATALOGUE 

GREGORY. Mathematics for Practical Men : 

Adapted to the Pursuits of Surveyors, Architects, Mechanics, and 
Civil Engineers. By OLINTHUS GREGORY. 8vo., plates $3.00 

GKISWOLD. Railroad Engineer's Pocket Companion for th 

Field : 

Comprising Rules for Calculating Deflection Distances and Angles, 
Tangential Distances and Angles, and all Necessary Tables for En 
gi'neers; also the Art of Levelling from Preliminary Survey to ih< 
Construction of Railroads, intended Expressly for the Young En- 
gineer, together with Numerous Valuable Rules and Examples. By 
W. GRISWOLD. I2mo., tucks ... . $^-S 

GRUNER. Studies of Blast Furnace Phenomena: 

By M. L. GRUNER, President of the General Council of Mines oi 
France, and lately Professor of Metallurgy at the Ecole des Mines 
Translated, with the author's sanction, with an Appendix, by L. D. 
B. GORDON, F. R. S. E., F. G. S. 8vo. . . . $2.50 

Hand-Book of Useful Tables for the Lumberman, Farmer and 

Mechanic : 

Containing Accurate Tables of Logs Reduced to Inch Board Meas. 
ure, Plank, Scantling and Timber Measure; Wages and Rent, by 
Week or Month; Capacity of Granaries, Bins and Cisterns; Land 
Measure, Interest Tables, with Directions for Finding the Interest on 
any sum at 4, 5, 6, 7 and 8 per cent., and many other Useful Tables. 
32 mo., boards, ibo pages .25 

HASERICK. The Secrets of the Art of Dyeing Wool, Cotton, 

and Linen, 

Including Bleaching an/i Coloring Wool and Cotton Hosiery and 
Random Yarns. A Treatise based on Economy and Practice. By 
E. C. HASERICK. Illustrated by 323 Dyed Patterns of the Yarm 
or fabrics. 8vo. ........ >5-oo 

HATS AND FELTING: 

A Practical Treatise on their Manufacture. By a Practical Hatte* 
Illustrated by Drawings of Machinery, etc. 8vo. . . $1.00 

HERMANN. Painting oil Glass and Porcelain, and Enamel 

Painting: 

A Complete Introduction to the Preparation of all the Colors and 
Fluxes Used for Painting on Glass, Porcelain, Enamel, Faience and 
Stoneware, the Color Pastes and Colored Glasses, together with a 
Minute Description ot the Firing ot Colors and Enamels, on thf 
Basis of Personal Practical Experience of the Art up to Date. 18 
illustrations. Second edition. $4.00 

HAUPT. Street Railway Motors: 

With Descriptions and Cost of Plants and Operation of the Varioui 
Systems now in Use. I2tw>. ... $1-75 



HENRY CAREY BAIRD & CO.'S CATALOGUE. 15 

HAUPT. A Manual of Engineering Specifications and Con- 
tracts. 
By LEWIS M. HAUPT, C. E. Illustrated with numerous maps. 

328pp. 8vo , ,...';' . . . 1300 

HAUPT. The Topographer, His Instruments and Methods. 
By LEWIS M. HAUPT, A. M., C. E. Illustrated with numerous 
plates, maps and engravings. 247 ppl 8vo. . ' . . $3.00 
HUGHES. American Miller and Millwright's Assistant: 

By WILLIAM CARTER HUGHES. I2mo $1.50 

HULME. Worked Examination Questions in Plane Geomet- 
rical Drawing : 

For the Use of Candidates for the Royal Military Academy, Wool- 
wich; the Royal Military College, Sandhurst ; the Indian Civil En- 
gineering College, Cooper's Hill ; Indian Public Works and Tele- 
graph Departments ; Royal Marine Li^ht Infantry ; the Oxford and 
Cambridge Local Examinations, etc. By F. EDWARD HULME, F. L. 
S., F. S. A., Art-Master Marlborough College. Illustrated by 300 

examples. Small quarto $1.00 

JEKVIS. Railroad Property: 

A Treatise on the Construction and Management of Railways; 
designed to afford useful knowledge, in the popular style, to the 
holders of this class of property ; as well as Railway Manager-s, ()ffi 
cers, ar.d Agents. By JOHN B. JERVIS, late Civil Engineer of the 
Hudson River Railroad, Croton Aqueduct, etc. i2mo., cloth 1.50 
KEENE. A Hand-Book of Practical Gauging: 
For the Use of Beginners, to which is added a Chapter on Distilla 
tion, describing the process in operation at the Custom- House foi 
ascertaining the Strength of Wines. By JAMES B. KEENE, of H. M. 

Customs. 8vo $ loa 

KELLEY. Speeches, Addresses, and Letters on Industrial and 

Financial Questions : 

By HON. WILLIAM D. KELLEY. M. C. 544 pages, 8vo. . $2.50 
KOENIG. Chemistry Simplified: 

A Course of Lectures on the Non-Metals Based upon the Natural 
Evolution of Chemistry. Designed Primarily for Engineers. By 
GEORGE AUGUSTUS KOENIG, Ph. D., A. M., E. M., Professor of 
Chemistry, Michigan College of Mines, Houghton. Illustrated by 
103 Original Drawings. 449 pp. I2mo., (1906). . . $2.25 
KEMLO. Watch- Repairer's Hand-Book : 
Being a Complete Guide to the Young Beginner, in Taking Apart, 
Putting Together, and Thoroughly Cleaning the English Lever and 
other Foreign Watches, and all American Watches. By F. KMLO P 
\acticalWatchmaker. With Illustrations. lamo. $1.25 



t6 HENRY CAREY BAIRD & CO.'S CATALOGUE. 

KENTISH. A Treatise on a Box of Instruments, 

And the Slide Rule ; with the Theory of Trigonometry and Log* 
rithms, including Practical Geometry, Surveying, Measuring of Tim- 
ber, Cask and Malt Gauging, Heights, and Distances. By THOMAS 
KENTISH. In one volume. I2mo. .... $I.OC 

KERL The Assayer's Manual: 

An Abridged Treatise on the Docimastic Examination of Ores, and 
Furnace and other Artificial Products. By BRUNO KERL, Professor 
in the Royal School of Mines. Translated from the German by 
WILLIAM T. BRANNT. Second American edition, edited with Ex- 
tensive Additions by F. LYNWOOD GARRISON, Member of the 
American Institute of Mining Engineers, etc. Illustrated by 87 en- 
gravings. 8vo. (Third Edition in preparation. ) 

KICK. Flour Manufacture. 

A Treatise on Milling Science and Practice. By FREDERICK KICK 
Imperial Regierungsrath, Professor of Mechanical Technology in the 
imperial German Polytechnic Institute, Prague. Translated from 
the second enlarged and revised edition with supplement by H. H. 
P. POWLES, Assoc. Memb. Institution of Civil Engineers. Illustrated 
with 28 Plates, and 167 Wood-cuts. 367 pages. 8vo. . $10.00 

KINGZETT. The History, Products, and Processes of the 

Alkali Trade : 

including the most Recent Improvements. By CHARLES THOMAS 
Kfvr./ETT. Consulting Chemist. With 23 illustrations. 8vo. $2.50 
KIRK. The Cupola Furnace: 

A Practical Treatise on the Construction and Management of Foundry 
Cupolas. By EDWARD KIRK, Practical Moulder and Melter, Con- 
sulting Expert in Melting. Illustrated by 78 engravings. Second 
Edition, revised and enlarged. 450 pages. 8vo. 1903. $3-S 

LANDRIN. A Treatise on Steel: 

Comprising its Theory, Metallurgy, Properties, Practical Working, 
and Use. By M. H. C. LANDRIN, JR. From the French, by A. A. 

FESQUET. i2mo $2.50 

LANGBEIN. A Complete Treatise on the Electro-Deposi. 

tion of Metals : 

Comprising Electro-Plating and Galvanoplastic Operations, the De- 
position of Metals by the Contact and Immersion Processes, the Color- 
ing of Metals, the Methods of Grinding and Polishing, as well as 
Descriptions of the Electric Elements. Dynamo-Electric Machines, 
Thermo-Piles and of the Materials and Processes used in Every De- 
partment of the Ait. From the German of DR. GEORGE LANGBEIN, 
with additions by WM. T. BRANNT. Fifth Edition, thoroughly revised 
and much enlarged. 170 Engravings. 694 pages 8vq. 1905. $4.00 

UARDNER. The Steam-Engine : 

For the Use of Beginners. Illustrated. I2mo. . . 60 

LEHNER. The Manufacture of Ink: 

< Comprising the Raw Materials, and the Preparation df W^ting, 
Copying and Hektograph Inks, Safety Inks, Ink Extracts and Pow- 

t ders, etc. Translated from the German of SlGMUND LEHNER, with 
additions by WILLIAM T. BRANNT. Illustrated. 12010. 



HENRY CAREY BAIRD & CO.'S CATALOGUE. 17 

LARKIN. The Practical Brass and Iron Founder's Guide 
A Concise Treatise on Brass Founding, Moulding, the Metals and 
their Alloys, etc.; to which are added Recent Improvements in thf 
Manufacture of Iron, Steel by the Bessemer Process, etc., etc. Bj 
JAMES LARKIN, late Conductor of the Brass Foundry Department if 
Reany, Neafie & Co.'s Penn Works, Philadelphia. New edition, 
revised, with extensive additions. 414 pages. 1 20x0. . $2,50 

LEROUX. A Practical Treatise on the Manufacture of 

Worsteds and Carded Yarns : 

Comprising Practical Mechanics, with Rules and Calculations applied 
to Spinning; Sorting, Cleaning, and Scouring Wools; the English 
and French Methods of Combing, Drawing, and Spinning Worsteds, 
and Manufacturing Carded Yarns. Translated from the French of 
CHARLES LEROUX, Mechanical Engineer and Superintendent of a 
Spinning-Mill, by HORATIO PAINE, M. D., and A. A. FESQUET, 
Chemist and Engineer. Illustrated by twelve large Plates. To which 
is added an Appendix, containing Extracts from the Reports of the 
International Jury, and of the Artisans selected by the Committed 
appointed "by the Council of the Society of Arts, London, on Woolei 
and Worsted Machinery and Fabrics, as exhibited in the Paris Uni 
versai Exposition, 1867. 8vo. $,4- 

LJEFFEL. The Construction of Mill-Dams : 
Comprising also the Building of Race and Reservoir Embankment! 
And Head-Gates, the Measurement of Streams, Gauging of Water 
Supply, etc. By JAMES LEFFEL & Co. Illustrated by 58 engravings. 
8vo. (Scarce.) 

LESLIE. Complete Cookery: 

Directions for Cookery in its Various Branches. By Miss LESLIE. 
Sixtieth thousand. Thoroughly revised, with the addition of New 
Receipts. I2mo. ... . $1.50 

LE VAN. The Steam Engine and the Indicator : 

Their Origin and Progressive Development; including the Most 
Recent Examples of Steam and Gas Motors, together with the Indi- 
cator, its Principles, its Utility, and its Application. By WILLIAM 
BARNET LE VAN. Illustrated by 205 Engravings, chisfly of Indi- 
cator-Cards. 469 pp. 8vo . $2.00 

LIEBER. Assayer's Guide ; 

Or, Practical Directions to Assayers, Miners, and Smelters, for the 
Tests and Assays, by Heat and by Wet Processes, for the Ores of all 
tfr principal Metals, of Gold and Silver Coins aad Alloys, and of 
Coal, etc. By OSCAR M. LIEBER. Revised. 283 pp. I2mo. $1.50 

Cockwood's Dictionary of Terms : 

Used in the Practice of Mechanical Engineering, embracing those 
Current in the Drawing Office, Pattern Shop, Foundry, Fitting, Turn- 
ing, Smith's and Boiler Shops, etc., etc., comprising upwards of Six 
Thousand Definitions. Edited by a Foreman Pattern Maker, author 
>f " Pattern Making." 417 pp. I2mo. . . . 



18 HENRY CAREY BAIRD & CO.'S CATALOGUE 

LUKIN. The Lathe and Its Uses : 

Or Instruction in the Art of lurning Wood and Metal. Including 
& Description of the Most Modern Appliances for the Ornamentation 
of Plane and Curved Surfaces, an Entirely Novel Form of Lathe 
for Eccentric and Rose-Engine Turning; A Lathe and Planing 
Machine Combined; and Other Valuable Matter Relating to the 
Art. Illustrated by 462 engravings. Seventh edition. 315 pages. 

Svo $4-25 

MAIN and BROWN. Questions on Subjects Connected with 

the Marine Steam-Engine : 

And Examination Papers' with Hints for their Solution. B> 
THOMAS J. MAIN, Professor of Mathematics, Royal ^aval College, 
and THOMAS BROWN, Chief Engineer, R. N. I2mo., cloth . $1.00 
MAIN and BROWN. The Indicator and Dynamometer: 
With their Practical Applications to the Steam-Engine. By THOMAS 
J. MAIN, M. A. F. R., Ass't S. Professor Royal Naval College, 
Portsmouth, and THOMAS BROWN, Assoc. Inst. C. E., Chief Engineei 
R. N., attached to the R. N. College. Illustrated. Svo. . 
MAIN and BROWN. The Marine Steam-Engine. 
By THOMAS J. MAIN, F. R. Ass't S. Mathematical Professor at the 
Royal Naval College, Portsmouth, and THOMAS BROWN, Assoc. 
Inst. C. E., Chief Engineer R. N. Attached to the Royal Navai 
College. With numerous illustrations. Svo. 
MAKINS. A Manual of Metallurgy: 

By GEORGE HOGARTH MAKINS. 100 engravings. Second edition 
rewritten and much enlarged. I2mo.. 592 pages 

MARTIN. Screw-Cutting Tables, for the Use of Mechanic^ 

Engineers : 

Showing the Proper Arrangement of iVheels for Cutting the Threads 
of Screws of any Required Pitch; with a Table for Making the Uni 
versal Gas-Pipe Thread and Taps. By W. A. MARTIN, Engineer. 

Svo .50 

MICHELL. Mine Drainage: 

Being a Complete and Practical Treatise on Direct-Acting Under 
rrcund Steam Pumping Machinery. With a Description of a large 
number of the best known Engines, their General Utility and ih 
Special Sphere of their Action, the Mode of their Application, and 
their Merits compared with other Pumping Machinery- By STEPHEN 
MICHKI.L. Illustrated by 247 engravings. 8 vo., 369 pages. $1250 
MOLESWORTH Pocket-Book of Useful Formulae and 
Memoranda for Civil and Mechanical Engineers. 
By GUILFORD L. MOLESWORTH, Member of the Institution of Civil 
Engineers, Chief Resident Engineer of the Ceylon Railway. Full- 
bound in Pocket-book form . 



ilENRY CAREY BAIRD & CO.'S CATALOGUE '9 

MOORE. The Universal Assistant and the Complete Mi 
cnanit: 

Containing over one million Industrial Facts, Calculations, Receipt^ 
Processes, Trades Secrets, Rules, Business Forms, Legal Items, Etc., 
in every occupation, from the Household to the Manufactory. Bj 
R. MOORE. Illustrated by 500 Engravings. I2mo. . 2.50 

MORRIS. Easy Rules for the Measurement of Earthworks : 
By means of the Prismoidal Formula. Illustrated with Numerouf 
Wood-Cuts, Problems, and Examples, and concluded by an Exten- 
sive Table for finding the Solidity in cubic yards from Mean Areas, 
The whole being adapted for convenient use by Engineers, Surveyor^ 
Contractors, and others needing Correct Measurements of Earthwork 
By ELWOOD MORRIS, C. E. 8vo $1.5* 

MAUCHLINE. The Mine Foreman's Hand-Book 

Of Practical and Theoretical Information on the Opening, Venti. 
lating, and Working of Collieries. Questions and Answers on Prac- 
tical and Theoretical Coal Mining. Designed to Assist Students and 
Others in Passing Examinations for Mine Foremanships. By 
ROBERT MAUCHLINE. 3d Edition. Thoroughly Revised and En- 
larged by F. ERNEST BRACKETT. 134 engravings, 8vo. 378 pages. 
(W) ^3.75 

NAPIER. A System of Chemistry Applied to Dyeing. 
By JAMES NAPIER, F. C. S. A New and Thoroughly Revised Ed* 
tion. Completely brought up to the present state of the Science, 
including the Chemistry of Coal Tar 'Colors, by A. A. FESQUET, 
Chemist and Engineer. With an Appendix oa Dyeing and Calic 
Printing, as shown at the Universal Exposition, Paris, 1867. Illus- 
trated. Svo. 422 pages $2.50 

NEVILLE. Hydraulic Tables, Coefficients, and Formula, fo 
finding the Discharge of Water from Orifices, Notches 
Weirs, Pipes, and Rivers : 

Third Edition, with Additions, consisting of New Formulae for the 
>ischarge from Tidal and Flood Sluices and Siphons; general infor 
nation on Rainfall, Catchment-Basins, Drainage, Sewerage, Wa;ei 
Supply for Towns and Mill Power Bv TOHN NEVTT.LK. C. E. M R 
I. A. ; Fellow of the Royal Geological Society of Ireland. Thid 

I2mo $5.5 

4EWBERY. Gleanings from Ornamental Art of everj 

style : 

Drawn from Examples in the British, South Kensington, Indian, 
Crystal Palace, and other Museums, the Exhibitions of 1851. and 
1862, and the best English an'd Foreign works. In a series of loo 
exquisitely drawn Plates, containing many hundred examples. By 
ROBERT NEWBERY. 410. . . . % y . (Scarce.) 

NICHOLLS. -The Theoretical and Practical Boiler- Maker and 

Engineer's Reference Book: 

Containing a variety of Useful Information for Employers of Labor 
Foremen a*%i Working Boiler-Makers. Iron, Copper, and Tinsmiths 



HENRY CAREY BAIRD & CO.'S CATALOGUE. 



Iwaoghtsmen, Engineers, the General Steam-using Public, and for th 
Use of Science Schools and Classes. By SAMUEL NICHOLLS. Illu 
trated by sixteen plates, I2mo. $2.50 

NICHOLSON. A Manual of the Art of Bookbinding : 
Containing full instructions in the different Branches of Forwarding, 
Gilding, and Finishing. Also, the Art of Marbling Book-edges and 
Paper. By JAMES B. NICHOLSON. Illustrated. I2mo., cloth $2.25 

NICOLLS. The Railway Builder: 

A Hand-Book for Estimating the Probable Cost of American Rail- 
way Construction and Equipment. By WILLIAM J. NlCOLLS, Civil 
Engineer. Illustrated, full bound, pocket-book form . $2.00 

NORMANDY. The Commercial Handbook of Chemical An- 

alysis : 

Or Practical Instructions for the Determination of the Intrinsic 01 
Commercial Value of Substances used in Manufactures, in Trades, 
and in the Arts. By A. NORMANDY. New Edition, Enlarged, and 
Co a great extent rewritten. By HENRY M. NOAD, Ph.D., F.R.S., 
thick I2mo Scarce 

NORRIS. A Handbook fcr Locomotive Engineers and Ma 

chinists : 

Comprising the Proportions and Calculations for Constructing Loco 
motives; Manner of Setting Valves; Tables cf Squares, Cubes, Areas, 
etc., etc. By SEPTIMUS NORRIS, M. E. New edition. Illustrated, 
I2mo $i.5C 

NYSTROM. A New Treatise on Elements of Mechanics : 
Establishing Strict Precision in the Meaning of Dynamical Terms 
accompanied with an Appendix on Duodenal Arithmetic and Me 
trology. By JOHN W. NYSTROM, C. E. Illustrated. 8vo. 

NYSTROM. On Technological Education and the Construe* 

tion of Ships and Screw Propellers : 

For Naval and Marine Engineers. By JOHN W. NYSTROM, Inn 
Acting Chief Engineer, U. S. N. Second edition, revised, with addi 
tional matter. Illustrated by seven engravings, izmo. . $1.25 

O'NEILL. A Dictionary of Dyeing and Calico Printing: 
Containing a brief account of all rhe Substances and Processes]* 
use in the Art of Dyeing and Printing Textile Fabrics ; with PractPc^ 
Receipts and Scientific Information. By CHARLES O'NEILL, Anal> x 
tical Chemist. To which is added an Essay on Coal Tar Colors and 
their application to Dyeing and Calico Printing. By A. A. FESQUET 
Chemist and Engineer. With an appendix on Dyeing and Calico 
Printing, as shown at the Universal Exposition, Paris, 1867- 8vo., 
491 pages . .".... * 2 50 

ORTON. Underground Treasures-. 

How and Where to Find Them. A Key for the Ready Determination 
of all the Useful Minerals within the United States. By JAMES 
o*i\JK, A.M., Late Professor of Natural H : story in Vassar College, 
N. Y ; author of the " Andes and the Amazon," etc. A New Edi- 
tion, with An Appendix on Ore Deposits and Testing Minerals ( 



HENRY CAREY BAIRD & CO.'S CATALOGUE. 21 

OSBORN. The Prospector's Field Book and Guide. 

In the Search For and the Easy ^Determination of Ores and Other 
Useful Minerals. By Prof. H. S. OSBORN, LL. D. Illustrated by 66 
Engravings. Seventh Edition. Revised and Enlarged. 379 pages, 

I2mo. (March, 1907) $1.50 

OSBORN A Practical Manual of Minerals, Mines and Min- 
ing : 

Comprising the Physical Properties, Geologic Positions, Local Occur- 
rence and Associations of the Useful Minerals; their Methods of 
Chemical Analysis and Assay ; together with Various Systems of Ex- 
cavating and Timbering, Brick and Masonry Work, during Driving, 
Lining, Bracing and other Operations, etc. By Prof. H. S. OSBORN, 
LL, D., Author of The Prospector's Field- Book and Guide." 171 
engravings. Second Edition, revised. 8vo. . . . 4.50 

OVERMAN. The Manufacture of Steel : 

Containing the Practice and Principles of Working and Making Steel. 
A Handbook for Blacksmiths and Workers in Steel and Iron, Wagon 
Makers, Die Sinkers, Cutlers, and Manufacturers of Files and Hard- 
ware, of Slcel and Iron, and for Men of Science and Art. By 
FREDERICK OVERMAN, Mining Engineer, Author of the " Manu- 
facture of lion," etc. A new, enlarged, and revised Edition. By 
A. A. FESQbrr, Chemist and Engineer. I2mo. . . $1.50 
3VERMAN. The Moulder's and Founder's Pocket Guide : 
A Treatise on Mouldingand Founding in Green-sand, Dry -sand, Loam, 
and Cement; the Moulding of Machine Frames, Mill-gear, Hollow- 
ware, Ornaments, Trinkets, Bells, and Statues ; Description of Moulds 
for Iron, Bronze, Brass, and other Metals ; Plaster of Paris, Sulphur, 
Wax, etc. ; the Construction of Melting Furnaces, the Melting and 
Founding of Metals ; the Composition of Alloys and their Nature, 
etc., etc. By FREDERICK OVERMAN, M. E. A new Edition, to 
which is added a Supplement on Statuary and Ornamental Moulding, 
Ordnance, Malleable Iron Castings, etc. By A. A. FESQUET, Chen> 
ist and Engineer. Illustrated by 44 engravings. I2mo. . 2.00 
PAINTER, GILDER, AND VARNISHER'S COMPANION. 
Comprising the Manufacture and Test of Pigments, the Arts of Paint- 
ing, Graining, Marbling, Staining, Sign- writing, Varnishing, Glass- 
staining, and Gilding on Glass ; together with Coach Painting and 
Varnishing, and the Principles of the Harmony and Contrast of 
Colors. Twenty-seventh Edition. Revised, Enlarged, and in great 
part Rewritten. By WILLIAM T. BRANNT, Editor of " Varnishes, 
Lacquers, Printing Inks and Sealing Waxes." Illustrated. 395 pp. 
I2mo. . . . , . . . . . . $i 50 

PALLETT. The Miller's, Millwright's, and Engineer's Guide. 
By HENRY PALLETT. Illustrated. 12010. . . . $2.00 



22 riENRY CAREY BAIRt) & CO.'S CATALOGUE. 

PERCY. The Manufacture of Russian Sheet-Iron. 

By JOHN PERCY, M. D., F. R. S. Paper. .... 25 cts, 
PERKINS. Gas and Ventilation : 

Practical Treatise on Gas and Ventilation. Illustrated. I2mo. $1.25 
PERKINS AND STOWE. A New Guide to the Sheet-iron 

and Boiler Plate Roller : 

Containing a Series of Tables showing the Weight of Slabs and Piles 
to Produce Boiler Plates, and of the Weight of Piles and the Sizes of 
Bars to produce Sheet-iron ; the Thickness of the Bar Gauge 
in decimals; the Weight per foot, and the Thickness on the Bar or 
Wire Gauge of the fractional parts of an inch; the Weight per 
sheet, and the Thickness on the Wire Gauge of Sheet-iron of various 
dimensions to weigh 112 Ibs. per bundle; and the conversion of 
Short Weight into Long Weight, and Long Weight into Short. 

$1.5 

POSSELT. Recent Improvements in Textile Machinery Re- 
lating to Weaving : 

Giving the Most Modern Points on the Construction of all Kinds 
of Looms, Warpers, Beamers, Slashers, Winders, Spoolers, Reeds, 
Temples, Shuttles, Bobbins, Heddles, Heddle Frames, Pickers, 
Jacquards, Card Stampers, etc., etc. 600 ill us. . . $3 .00 
POSSELT. Technology of Textile Design: 
The Most Complete Treatise on the Construction and Application 
of Weaves for all Textile Fabrics and the Analysis of Cloth. By E. 

A. Posselt. 1,500 illustrations. 410 $5-OO 

POSSELT. Textile Calculations: 

A Guide to Calculations Relating to the Manufacture of all Kinds 
of Yarns and Fabrics, the Analysis of Cloth, Speed, Power and Belt 
Calculations. By E. A. POSSELT. Illustrated. 410. . $2.00 
REGNAULT. Elements of Chemistry: 

By M. V. REGNAULT. Translated from the French by T. FORREST 
BETTON, M. D., and edited, with Notes, by JAMES C. BOOTH, Melter 
and Refiner U. S. Mint, and WILLIAM L. FABER, Metallurgist and 
Mining Engineer. Illustrated by nearly 700 wood-engravings. Com- 
prising nearly 1,500 pages. In two volumes, 8vo., cloth . $6.00 
RICHARDS. Aluminium : 

Its History, Occurrence, Properties, Metallurgy and Applications, 
including its Alloys. By JOSEPH W. RICHARDS, A. C., Chemist and 
Practical Metallurgist, Member of the Deutsche Chemische Gesell- 
schaft. Illust. Third edition, enlarged and revised (1895) . $6.OO 
fclFFAULT, VERGNAUD, and TOUSSAINT. A Practical 

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Comprising the Origin, Definition, and Classification of Colors; the 
Treatment of the Raw Materials ; the best Formulae and the Newest 
Processes for the Preparation of every description of Pigment, and 
the Necessary Apparatus and Directions for its Use; Dryers; the 
Testing. Application, and Qualities of Paints, etc., etc. By MM. 
RIFFAULT, VERGNAUD, and TOUSSA'INT. Revised and Edited by M 



HENRY CAREY BAIRD & CO.'S CATALOGUE. 



F. MALEPEYRE. Translated from the French, by A. A. 

Chemist and Engineer. Illustrated by Eighty engravings. In one' 

vol.. "8vo., 659 pages . ' ...... $5- 

ROPER. Catechism for Steam Engineers and Electricians: 
Including the Construction and Management of Steam Engines, 
Steam Boilers and Electric Plants. By STEPHEN ROPER. Twenty- 
first edition, rewritten and greatly enlarged by E. R. KELLER and 
C. W. PIKE. 365 pages. Illustrations. i8mo., tucks, gilt. $2.00 

ROPER. Engineer's Handy Book: 

Containing Facts, Formulae, Tables and Questions on Power, its 
Generation, Transmission and Measurement; Heat, Fuel, and Steam; 
The Steam Boiler and Accessories; Steam Engines and their Parts; 
Steam Engine Indicator; Gas and Gasoline Engines; Materials; 
their Properties and Strength ; Together with a Discussion of the Fun- 
damenial Experiments in Electricity, and an Explanation of Dynamos, 
Motors, Batteries, etc., and Rules for Calculating Sizes of Wires. By 
STEPHEN ROPER. I5ih edition. Revised and enlarged by E. R. 
KELLER, M. E. and C. W. PIKE, B. S. (1899), with numerous illus- 
trations. Pocket-book form. Leather ..... $3*5 

ROPER. Hand-Book of Land and Marine Engines : 
Including the Modelling, Construction, Running, and Management 
of Lane 1 and Marine Engines and Boilers. With illustrations. By 
STEPHEN ROPER, Engineer. Sixth edition. I2mo.,rvcks, gilt edge. 

*3-5<J 
ROPER. Hand-Book of the Locomotive : 

Including the Construction of Engines and Boilers, and the Construc- 
tion, Management, and Running of Locomotives. By STEPHEN 
ROPER. Eleventh edition. i8mo., tucks, gilt edge . 2.50 

ROPER. Hand-Book of Modern Steam Fire-Engines. 
With illustrations. By STEPHEN ROPER, Engineer. Fourth edition, 
I2mo., tucks, gilt edge ....... $3-50 

ROPER. Questions- and Answers for Engineers. 

This little book contains all the Questions that Engineers will be 
asked when undergoing an Examination for the purpose of procuring 
Licenses, and they are so plain that any Engineer or Fireman of or- 
dinary intelligence may commit them to memory in a short time. By 
STEPHEN ROPER, Engineer. Third edition . . . $2.00 
ROPER. Use and Abuse of the Steam Boiler. 
By STEPHEN ROPER, Engineer. Eighth edition, with illustrations. 
l8mo., tucks, gilt edge ....... $2.00 

ROSE. The Complete Practical Machinist : 

Embracing Lathe Work, Vise Work, Drills and Drilling, Taps and 
Dies, Hardening and Tempering, the Making and Use of Tools 
Tool Grinding, Marking out Work, Machine Tools, etc. By JOSHUA 
ROSE. 39^ Engravings. Nineteenth Edition, greatly Enlarged with 
New and Valuable Matter. I2mo., 504 pages. . . $2.50 
ROSE. Mechanical Drawing Self-Taught : 

Comprising Instructions in the Selection and Preparation of Drawing 
T nstruments, Elementary Instruction in Practical Mechanical Draw- 



4 HENRY CAREY BAIRD & CO.'S CATALOGUE. 

ing, together with Examples in Simple Geometry and Elementary 
Mechanism, including Screw Threads, Gear Wheels, Mechanical 
Motions, Engines and Boilers. By JOSHUA ROSE, M. E. Illustrated 
by 330 engravings. 8vo , 313 pages .... $4.00 

ROSE. The Slide- Valve Practically Explained: 

Embracing simple and complete Practical Demonstrations of th> 
operation of each element in a Slide-valve Movement, and illustrat- 
ing the effects of Variations in their Proportions by examples care, 
fully selected from the most recent and successful practice. By 
JOSHUA ROSE, M. E. Illustrated by 35 engravings . $1.00 

ROSS. The Blowpipe in Chemistry, Mineralogy and Geology: 
Containing all Known Methods of Anhydrous Analysis, many Work- 
ing Examples, and Instructions for Making Apparatus. By LIEUT.- 
COLONEL W. A. Ross, R. A., ,F. G. S. With 120 Illustrations, 
I2mo $2.00 

SHAW. Civil Architecture : 

Being a Complete Theoretical and Practical System of Building, con- 
taining the Fundamental Principles of the Art. By EDWARD SHAW, 
Architect. To which is added a Treatise on Gothic Architecture, etc. 
By THOMAS W. SILLOWAY and GEORGE M. HARDING, Architects. 
The whole illustrated by 102 quarto plates finely engraved on copper. 
Eleventh edition. 4to. $6.00 

8HUNK. A Practical Treatise on Railway Curves and Loca- 
tion, for Young Engineers. 
By W. F. SHUNK, C. E. I2mo. Full bound pocket-book form $2.00 

SLATER. The Manual of Colors and Dye Wares. 
By J. W. SLATER. i2mo. ...... $3.00 

SLOAN. American Houses : 

A variety of Original Designs for Rural Buildings. Illustrated by 
26 colored engravings, with descriptive references. By SAMUEL 
SLOAN, Architect. 8vo. .75 

SLOAN. Homestead Architecture : 

Containing Forty Designs for Villas, Cottages, and Farm-houses, with 
Essays on Style, Construction, Landscape Gardening, Furniture, etc., 
etc. Illustrated by upwards of 200 engravings. By SAMUEL SLOAN, 
Architect. 8vo #2.50 

8LOANE. Hoir>e Experiments m Science. 
By T. O'CoNOR SLCANE, E. M., A. M., Fh. D. Illustrated by 91 
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SMEATON. Builder's Pockt^Companion : 

Containing the Elements of Building, Surveying, and Architecture; 

with Practical Rules and Instructions connected with the subject. 

By A. C. SMEATON, Civil Engineer, etc. I2mo. 
SMITH. A Manual of Political Economy. 

By E. PESHINE SMITH. A New Edition, to which is added a full 

Index. I2mo. 1 1 25 



HENRY CAREY BAlRD & CO.'S CATALOGUE. 25 

SMITH. Parks and Pleasure - Grounds : 

Or Practical Notes on Country Residences, Villas, Public Parks, and 
Gardens. By CHARLES H. J. SMITH, Landscape Gardener and 
Garden Architect, etc., etc. I2mo. .= .- . . $2.00 

SMITH. The Dyer's Instructor: 

Comprising Practical Insfuctions in the Art of Dyeing Silk, Cotton, 
Wool, and Worsted, and Woolen Goods ; containing nearly 800 
Receipts. To which is added a Treatise on the Art of Padding; and. 
the Printing of Silk Warps, Skeins, and Handkerchiefs, and th 
various Mordants and Colors for the different styles of such work. 
By DAVID SMITH, Pattern Dyer. I2mo. . . . $1.00 

SMYTH. A Rudimentary Treatise on Coal and Coal-Mining. 
By WARRINGTON W. SMYTH, M. A., F. R. G., President R. G. S. 
of Cornwall. Fifth edition, revised and corrected. With ftumer- 
ous illustrations. I2mo. Si. 40 

SNIVELY. Tables for Systematic Qualitative Chemical Anal. 

ysis. 
By JOHN H. SNIVELY, Phr. D. 8vo. .... $1.00 

SNIVELY. The Elements of Systematic Qualitative chemical 

Analysis : 

A Hand-book for Beginners. By JOHN H. SNIVELY, Phr. D. i6mo. 

$2.00 

STOKES. The Cabinet Maker and Upholsterer's Companion: 
Comprising the Art of Drawing, as applicable to Cabinet Work; 
Veneering, Inlaying, and Buhl- Work ; the Art of Dyeing and Stain 
ing Wood, Ivory, Bone, Tortoise-Shell, etc. Directions for Lacker- 
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Cements, and Compos : .i<- ns ; with numerous Receipts, useful to work 
men generally. Bv STOKES. Illustrated. A New Edition, with 
an Appendix upor ,ench Polishing, Staining, Imitating, Varnishing, 
etc., etc. I2mo $1.25 

STRENGTH AND OTHER PROPERTIES OF METALS; 

Reports of Experiments on the Strength and other Properties of 
Metals for Cannon. With a Description of the Machines for Testing 
Metals, and of the Classification of Cannon in service. By Officer? 
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SULLIVAN. Protection to Native Industry. 
By Sir EDWARD SULLIVAN, Baronet, author of " Ten Chapters on 
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SHERRATT. The Elements of Hand-Railing: 

Simplified and Explained in Concise Problems that are Easily Under- 
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Make Rail Without Centre Joints, Making Better Rail of the Same 
Material, with Half the Lalx>r, and Showing How to Lay Out Stairs 
of all Kinds. By R, J. SHERRATT. Folio. . . . 52.50 



26 HENRY CAREY BAIRr? & CO.'S CATALOGUE. 



SYME. Outlines of an Industrial Science. 
By DAVID SYME. 121110. . ... $2.00 

TABLES SHOWING THE WEIGHT , OF ROUND, 

SQUARE, AND FLAT BAR IRON, STEEL, ETC., 
By Measurement. Cloth ...... 63 

THALLNER. Tool-Steel : 

A Concise Handbook on Tool-Steel in General. Its Treatment In 
the Operations of Forging, Annealing, Hardening, Tempering, etc., 
and the Appliances Therefor. By OTTO THALLNER, Manager in 
Chief of the Tool-Steel Works, Bismarck hiitte, Germany. From the 
German by WILLIAM T. BRANNT. Illustrated by 69 engravings. 
194 pages. 8vo. 1902. ...... $2.00 

TEMPLETON. The Practical Examinator on Steam and thd 

Steam-Engine: 

With Instructive References rela'.ive thereto, arranged for the Use of 
Engineers, Students, and others. By WILLIAM TEMPLETON, En. 
gineer. I2mo. ..... $1.00 

THAU SING. The Theory and Practice of the Preparation of 

Malt and the Fabrication of Beer: 

With especial reference to the Vienna Process of Brewing. Elab- 
orated from personal experience by JULIUS E. THAUSING, Professor 
at the School for Brewers, and at the Agricultural Institute, Modling, 
near Vienna. Translated from the German by WILLIAM T. BRANNT, 
Thoroughly and elaborately edited, with much American matter, and 
according to the latest and most Scientific Practice, by A. SCHWARZ 
and DR. A. H. BAUER. Illustrated by 140 Engravings. 8vo., 815 
pages .......... $10.00 

THOMPSON. Political Economy. With Especial Reference 

to the Industrial History of Nations : 

By ROBERT E. THOMPSON, M. A., Professor of Social Science in the 
University of Pennsylvania. I2mo. . . . $1.50 

THOMSON. Freight Charges Calculator: 

By ANDREW THOMSON, Freight Agent. 241110. . . $1.25 

TURNER'S (THE) COMPANION: 

Containing Instructions in Concentric, Elliptic, and Eccentric Turn, 
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Directions for using the Eccentric Cutter, Drill, Vertical Cutter, and 
Circular Rest; with Patterns and Instructions for working them. 
I2mo $I.oo 

TURNING : Specimens of Fancy Turning Executed on the 

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4*0 (Scarce.) 



HENRY CAREY BAIRB & CO.'S CATALOGUE. vj 

VAILE. Galvanized-Irog Cornice-Worker's Manual : 

Containing Instructions in Laying out the Different Mitres, and 
Making Patterns for all kinds of Plain and Circular Work. Also, 
Tables of Weights, Areas and Circumferences of Circles, and other 
Matter calculated to Benefit the Trade. By CHARLES A. VAILE, 
Illustrated by twenty-one plates. 4to (Scarce.) 

VILLE. On Artificial Manures : 

Their Chemical Selection and Scientific Application to Agriculture. 
A series of Lectures given at the Experimental Farm at Vincennes, 
during 1867 and 1874-75. By M. GEORGES VlLLE. Translated and 
Edited by WILLIAM CROOKES, F. R. S. Illustrated by thirty-one 
engravings. 8vo., 450 pages . . , . . . $6.00 

VILLE. The School of Chemical Manures : 
Or, Elementary Principles in the Use of Fertilizing Agents. From 
the French of M. GEO. VILLE, by A. A. FESQUET, Chemist and En- 
gineer. With Illustrations. I2mo. . . . . $1.2$ 

VOGDES. The Architect's and Builder's Pocket- Companion 

and Price-Book: 

Consisting of a Shoit but Comprehensive Epitome of Decimals, Duo- 
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Measures, Sizes, Weights, Strengths, etc., of Iron, Wood, Stone, 
Brick, Cement and Concretes, Quantities of Materials in given Sizes 
and Dimensions of Wood, Brick and Stone; and full and complete 
Bills of Prices for Carpenter's Work and Painting; also, Rules for 
Computing and Valuing Brick and Brick Work, Stone Work, Paint- 
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FRANK W. VOGDES, Architect, Indianapolis, Ind. Enlarged, revised, 
and corrected. In one volume, 368 pages, full-bound, pocket-book 

form, gilt edges $2.00 

Cloth . 1.59 

VAN CLEVE. The English and American Mechanic: 
Comprising a Collection of Over Three Thousand Receipts, Rules, 
and Tables, designed for the Use of every Mechanic and Manufac- 
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VAN DER BURG. School of Painting for the Imitation of 

Woods and Marbles: 

A Complete, Practical Treatise on the Art and Craft of Graining and 
Marbling with the Tools and Appliances. 36 plates. Folio, 12 x 20 
inches. . . "?.-: . *. * . $6.00 

WAHNSCHAFFE. A Guide to the Scientific Examinatioa 

of Soils: 

Comprising Select Methods of Mechanical and Chemical A lalysi* 
and Physical Investigation. Translated from the German of Dr. F. 
WAHNSCHAFFE. With additions by WILLIAM T. BRANNT. Illus- 
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IV ALTON- Coal-Mining Described and Illustrated: 
By THOMAS H. WALTON, Mining Engineer. Illustrated by 24 ?argi 
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2' v HENRY CAREY BAIRD & CO.'S CATALOC UE, 

WARE. The Sugar Beet. 

Including a History of the Beet Sugar Industry in Europe, Varietie 
of the Sugar Beet, Examination, Soils, Tillage, Seeds and Sowing 
Yield and Cost of Cultivation, Harvesting, Transportation, Conserva 
tion, Feeding Qualities of the Beet and of the Pulp, etc. By LEWH 
S. WARE, C. ., M. E. Illustrated by ninety engravings. 8vo. 

$3-50 

WARN. The Sheet-Metal Worker's Instructor: 

For Zinc, Sheet- Iron, Copper, and Tin- Plate Workers, etc. Contain- 
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Rules for Describing the various Patterns required in the different 
branches of the above Trades. By REUBEN H. WARN, Practical 
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Instructions for Boiler-Making, Mensuration of Surfaces and Solids, 
Rules for Calculating the Weights of different Figures of Iron and 
Steel, Tables of the Weights of Iron, Steel, etc. Illustrated by thirty- 
two Plates and thirty-seven Wood Engravings. 8vo. . $2.50 

WARNER. New Theorems, Tables, and Diagrams, for tht 
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Designed for the use of Engineers in Preliminary and Final Estimates 
of Students in Engineering, and of Contractors and other non-profes- 
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Containing Notes to the Rules and Examples of Part I.; Explana 
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Treatise upon Equivalent Square Bases and Equivalent Level Heights 
By JOHN WARNER, A. M., Mining and Mechanical Engineer. Illus- 
trated by 14 Plates. 8vo. ...... $3.00 

WILSON. Carpentry and Joinery : 

By JOHN WILSON, Lecturer on Building Construction, Carpentry and 
Joinery, etc., in the Manchester Technical School. Third Edition, 
with 65 full-page plates, in flexible cover, oblong. . . (Scarce.) 

WATSON. A Manual of the Hand-Lathe : 

Comprising Concise Directions for Working Metals of all kinds, 
Ivory, Bone, and Precious Woods ; Dyeing, Coloring, and French 
Polishing ; Inlaying by Veneers, and various methods practised to 
produce Elaborate work with Dispatch, and at Small Expense. By 
EGBERT P. WATSON, Author of "The Modern Practice of American 
Machinists and Engineers." Illustrated by 78 engravings. $1.50 

WATSON. The Modern Practice of American Machinists 
and Engineers : 

Including the Construction, Application, and Use of Drills, Lathe 
Tools, Cutters for Boring Cylinders, and Hollow-work generally, with 
the most Economical Speed for the same ; the Results verified by 
Actual Practice at the Lathe, the Vise, and on the floor. Togethei 



HENRY CAREY BAIRD & CO.'S CATALOGUE. 29 

with Workshop Management, Economy of Manufacture, the Steam 
Engine, Boilers, Gears, Belting, etc., etc. By EGBERT P. WATSON. 
Illustrated by eighty-six engravings. I2ino. . . . $2.50 

WATT. The Art of Soap Making : 

A Practical Hand-Book of the Manufacture of Hard and Soft Soaps, 
Toilet Soaps, etc. Fifth Edition, Revised, to which is added an 
Appendix on Modern Candle Making. By ALEXANDER WATT. 
111. I2mo. . . . $3.00 

WEATHERLY. Treatise on the Art of Boiling Sugar, Crys- 
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And other processes for Confectionery, including Methods for Manu- 
facturing every Description of Raw and Refined Sugar Goods. A 
New and Enlarged Edition, with an Appendix on Cocoa, Chocolate, 
Chocolate Confections, etc. 196 pages, I2mo. (1903) . 1.50 

WILL. Tables of Qualitative Chemical Analysis : 

With an Introductory Chapter on the Course of Analysis. By Pro- 
fessor HEINRICH WILL, of Giessen, Germany. Third American, 
from the eleventh German edition. Edited by CHARLES F. HIMES, 
Ph. D., Professor of Natural Science, Dickinson College, Carlisle, 
Pa. 8vo. . . . . . . . . . $1.50 

WILLIAMS. On Heat and Steam: 

Embracing New Views of Vaporization, Condensation and Explo- 
sion. By CHARLES WYE WILLIAMS, A. I. C. E. Illustrated. 8vo. 

$2.50 

WILSON. First Principles of Political Economy: 

With Reference to Statesmanship and the Progress of Civilization. 
By Professor W. D. WILSON, of the Cornell University. A new and 
revised edition. I2mo $1-5 

WILSON. The Practical Tool-Maker and Designer: 

A Treatise upon the Designing of Tools and Fixtures for Machine 
Tools and Metal Working Machinery, Comprising Modern Examples 
of Machines with Fundamental Designs for Tools for the Actual Pro- 
duciion of the work; Together with Special Reference to a Set of 
Tools for Machining the Various Parts of a Bicycle. Illustrated by 
189 engravings. 1898. . . . . * #2.50 

CONTENTS: Introductory. Chapter I. Modern Tool Room and Equipment. 
II. Files, Their Use and Abuse. III. Steel and Tempering. IV. Making Jigs. 
V. Milling Machine Fixtures. VI. Tools and Fixtures for Screw Machines. VII. 
Broaching. VIII. Punches and Dies for Cutting and Drop Press. IX. Tools for 
Hollow-Ware. X. Embossing: Metal, Coin, and Stamped Sheet-Metal Orna- 
ments. XI. Drop Forging. XII. Solid Drawn Shells or Ferrules ; Cupping or 
Cutting, and Drawing ; Breaking Down Shell-,. XIII. Annealing, Pickling, and 



Cleaning, XIV. Tools for Draw Bench. XV. Cutting and Assembling Pieces 
by Means of Ratchet Dial Plates at One Operation. XVI. The Header. XVII. 
Tools for Fox Lathe. XVIII. Suggestions for a Set of Tools for Machining the 



Various Parts of a Bicycle. XIX. The Plater's Dynamo. XX. Conclusion 
With a Few Random Ideas. Appendix. Index. 

WOODS Compound Locomotives: 

By ARTHUR TANNATT WOODS. Second edition, revised and enlarged 
by DAVID LEONARD BARNES, A. M., C. E. 8vo. 330 pp. $3.00 



HENRY CAREY BAIRD & CO.'S CATALOGUfe. 



WOHLER. A Hand-Bookof Mineral Analysis: 

By F. WOHLER, Professor of Chemistry in the University of Gottin- 
gen. Edited by HENRY B. NASON, Professor of Chemistry in the 
Renssalaer Polytechnic Institute, Troy, New York. Illustrated. 
I2mo. $2.50 

WORSSAM. On Mechanical Saws : 

From the Transactions of the Society of Engineers, 1869. By S. W. 
WORSSAM, JR. Illustrated by eighteen large plates. 8vo. $1.50 



RECENT ADDITIONS. 

BRANNT. Varnishes, Lacquers, Printing Inks and Sealing- 

Waxes : 

Their Raw Materials and their Manufacture, to which is added the 
Art of Varnishing and Lacquering, including the Preparation of Put- 
ties and of Stains for Wood, Ivory, Bone, Horn, and Leather. By 
WILLIAM T. BRANNT. Illustrated by 39 Engravings, 338 pages. 
I2mo $3.00 

BRANNT. The Practical Dry Cleaner, Scourer, and Gar- 
ment Dyer : 

Comprising Dry or Chemical Cleaning; Purification of Benzine; Re- 
moving Stains; Wet Cleaning; Finishing Cleaned Fabrics; Cleaning 
and Dyeing Furs, Skins, Rugs and Mats; Cleaning and Dyeing 
Feathers; Bleaching and Dyeing Straw Hats ; Cleaning and Dyeing 
Gloves: Garment Dyeing; Stripping, Analysis of Textile Fabrics. 
Edited by WILLIAM T. BRANNT, Editor of the " Techno-Chemical 
Receipt Book." 2nd edition, in great part re-written and much en- 
larged. Illustrated. 293 pages. I2mo. . . . $2.50 

BRAN NT. Petroleum . 

its History, Origin, Occurrence, Production, Physical and Chemical 
Constitution, Technology, Examination and Uses; Together with 
the Occurrence and Uses of Natural Gas. Edited chiefly from the 
German of Prof. Hans Hoefer and Dr. Alexander Veith, by WM. 
T. BRANNT. Illustrated by 3 Plates and 284 Engravings. 743 pp. 
8vo - #8.50 

BRANNT. A Practical Treatise on the Manufacture of Vine- 

gar and Acetates, Cider, and Fruit- Wines : 
Preservation of Fruits and Vegetables by Canning and Evaporation; 
Preparation of Fruit-Butters, Jellies, Marmalades, Catchups, Pickles, 
Mustards, etc. Edited from various sources. By WILLIAM T. 
BRANNT. Illustrated by 79 Engravings. 479 pp. Svo. $5.00 

BRANNT. The Metal Worker's Handy-Book of Receipts 
and Processes : 

Being a Collection of Chemical Formulas and Practical Manipula- 
tion-; for the working of all Metals; including the Decoration and 
Beautifying of Articles Manufactured therefrom, as well as their 
Preservation. Edited from various sources. By WILLIAM T. 
BRANNT. Illustrated. i2mo. | 2 50 



HENRY CAREY BAIRD & CO.'S CATALOGUE. 31 

DJEITE. A Practical Treatise on the Manufacture of Per- 
fumery : 

Comprising directions for making all Rinds of Perfumes, Sachet 
Powders, Fumigating Materials, Dentifrices, Cosmetics, etc., with a 
full account of the Volatile Oils, Balsams, Resins, and other Natural 
and Artificial Perfume-substances, including the Manufacture of 
Fruit Ethers, and tests of their purity. By Dr. C. DEITE. assisted 
by L. BORCHERT, F. EICHBAUM, E. KUGLER, H. TOEFFNER, and 
other experts. From the German, by WM. T. BRANNT. 28 Engrav- 
ings. 358 pages. 8vo. $3.00 

EDWARDS. American Marine Engineer, Theoretical and 

Practical : 

With Examples of the latest and most approved American Practice. 
By EMORY EDWARDS. 85 illustrations. I2mo. . . #2.00 

EDWARDS. 900 Examination Questions and Answers: 

For Engineers and Firemen (Land and Marine) who desire to ob- 
tain a United States Government or State License. Pocket-book 

form, gilt edge . . $1-5 

FLEMM ING. Practical Tanning: 

A Handbook of Modern Processes, Receipts, and Suggestions for the 
Treatment of Hides, Skins, and Pelts of Every Description. By 
Lewis A. Flemming. American Tanner. 472pp. 8 vo. (1903) #4.00. 

POSSELT. The Jacquard Machine Analysed and Explained: 
With an Appendix on the Preparation of Jacquard Cards, and 
Practical Hints to Learners of Jacquard Designing. By E. A. 
POSSELT. With 230 illustrations and numerous diagrams. 127 pp. 
4to- $3-0 

POSSELT. Recent Improvements in Textile Machinery. 

Part III: 

Processes Required for Converting Wool, Cotton, Silk, from Fibre 
to Finished Fabric, Covering both Woven and Knit Goods ; Con- 
struction of the most Modern Improvements in Preparatory Machin- 
ery, Carding, Combing, Drawing, and Spinning Machinery, Winding, 
Warping, Slashing Machinery Looms, Machinery for Knit Goods, 
Dye Stuffs, Chemicals, Soaps, Latest Improved Accessories Relat- 
ing to Construction and Equipment of Modern Textile Manufactur- 
ing Plants. By E. A. POSSELT. Completel- Illustrated. 410. 

7-50 

RICH. Artistic Horse-Shoeing: 

A Practical and Scientific Treatise, giving Improved Methods of 
Shoeing, with Special Directions for Shaping Shoes to Cure Different 
Diseases of the Foot, and for the Correction of Faulty Action in 
Trotters. By GEORGE E. RICH. 62 Illustrations. 153 pa.ses 
.... -V '' . . . |2.oo 




32 HENRY CAREY BAIRD & OCX'S CATALOGUE. 

RICHARDSON. Practical Blacksmithing : 
A Collection of Articles Contributed at Different Times by Skilled 
Workmen to the columns of " The Blacksmith and Wheelwright," 
and Covering nearly the Whole Range of Blacksmithing, from the 
Simplest Job of Work to some of the Most Complex Forgings. 
Compiled and Edited by M. T. RICHARDSON. 

Vol.1. 210 Illustrations. 224 pages. I2mo. . . $l.oo 
Vol. II. 230 Illustrations. 262 pages. I2mo. . $l.oo 
Vol. III. 390 Illustrations. 307 pages. I2mo. . . #I.oo 
Vol. IV. 226 Illustrations. 276 pages. I2mo. , . jjji.oo 

RICHARDSON. The Practical Horseshoer: 
Being a Collection of Articles on Horseshoeing in all its Branched 
which have appeared from time to time in the columns of " 1 he 
Blacksmith and Wheelwright," etc. Compiled and edited by M. T. 
RICHARDSON. 174 illustrations, #1.00 

ROPER. Instructions and Suggestions for Engineers and 

Firemen : 
By STEPHEN ROPER, Engineer. i8mo. Morocco . $2.00 

ROPER. The Steam Boiler: Its Care and Management: 
By STEPHEN ROPER, Engineer. I2mo., tuck, gilt edges. $2.00 

ROPER. The Young Engineer's Own Book: 

Containing an Explanation of the Principle and Theories on which 
the Steam Engine as a Prime Mover is Based. By STEPHEN ROPER. 
Engineer. 160 illustrations, 363 pages. iSmo., tuck . $2.50 

ROSE. Modern Steam- Engines: 

An Elementary Treatise upon the Steam-Engine, written in Plain 
language; for Use in the Workshop as well as in the Drawing Office. 
Giving Full Explanations of the Construction of Modern Steam. 
Engines : Including Diagrams showing their Actual operation. To 
gether with Complete but Simple Explanations of the operations of 
Various Kinds of Valves, Valve Motions, and Link Motions, etc., 
thereby Enabling the Ordinary Engineer to clearly Understand the 
Principles Involved in their Construction and Use, and to Plot out 
their Movements upon the Drawing Board. By JOSHUA ROSE. M. E. 
Illustrated by 422 engravings. Revised. 358 pp. . . $6.00 

ROSE. Steam Boilers: 

A Practical Treatise on Boiler Construction and Examination, for the 
Use of Practical Boiler Makers, Boiler Users, and Inspectors; and 
embracing in plain figures all the calculations necessary in Designing 
or Classifying Steam Boilers. By JOSHUA ROSE, M. E. Illustrated 
by 73 engravings. 250 pages. 8vo $2.<jo 

8CHRIBER. The Complete Carriage and Wagon Painter: 
A Concise Compendium of the Art of Painting Carriages, Wagon*, 
and Sleighs, embracing Full Directions in all the Various Branches, 
including Lettering, Scrolling, Ornamenting, Striping, Varnishing, 
and Coloring, with numerous Recipes for Mixing Colon. 73 Illus- 
trations. 177 pp. i2mo 



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