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V ! 

?-/- /-z 



REPRODUCED IN FACSIMILE 
BY 

WILLIAM DAWSON & SONS LTD 

102 WIGMORE STREET, 

LONDON, W I 

AND PRINTED BY 

HENDERSON & SPALDING 

SYLVAN GROVE OLD KENT ROAD 

LONDON S E 1 5 



THIS EDITION is LIMITED TO I 000 COPIES 



A TEXT-BOOK OF 

INOKGANIC CHEMISTKY. 



EDITED BY 

J NEWTON FRIEND, D So , PH D , F I , 



CARNEGIK GOLD MEDALLIST 



VOLUME II. 



THE ALKALI-METALS AND THEIR 

CONGENERS. 



BY 



A JAMIESON WALKER, 

PH D (HPID ), BA(QXTB) 1IC 



Mitb tfroutiepiece anD JHustratione 




*V 
a! 



I N D O N 

CHAKLhS GUIlJbIN cV COMPANY, LIMITED, 
STUEPT, STRAND, WC 2 

1924 
[ III iigh(t> IMC) icd ] 



GENERAL INTRODUCTION TO THE SERIES 

*! 

DURING the past few years the civilized world has begun to realize tBte 
advantages accruing to scientific research, with the result that an ever- 
increasing amount of time and thought is being devoted to various 
branches of science 

No study has progressed more rapidly than chemistry This 
science may be divided roughlv into several branches namely, Organic, 
Phvsical, Inorganic, and Analytical Chemistry It is impossible to 
write any single text-book which shall contain within its two covers 'a 
thorough treatment of any one of these branches, owing to the vast 
amount of information that has been accumulated The need is rather 
for a series of text-books dealing more or less comprehensively with 
each branch of chemistry This has already been attempted by 
enterprising firms, so far as physical and analytical chemistry are 
concerned , and the present series is designed to meet the needs of 
inorganic chemists One great advantage of this procedure lies in 
the fact that our knowledge of the different sections of science does not 
progress at the same rate Consequently, as soon as any particular 
part advances out of proportion to others, the volume dealing with 
that section may be easily revised or rewritten as occasion requires 

Some method of classifying the elements for treatment m this way 
is clearly essential, and we have adopted the Periodic Classification 
with slight alterations, devoting a whole volume to the consideration 
of the elements in each vertical column, as will be evident from a glance 
at the scheme in the Fiontispiece 

In the first volume, in addition to a detailed account of the elements 
of Group 0, the general principles of inorganic chemistry are discussed 
Particular pains have been taken in the selection of material for this 
volume, and an attempt has been made to present to the leader a 
clear account of the principles upon which 0111 knowledge of modern 
inorganic chemistry is based 

At the outset it may be well to explain that it was not intended 
to write a complete text book of physical chemistry Numerous 
excellent works have already been devoted to this subject, and a 
volume on such lines would scarcely serve as a suitable introduction 
to this series Whilst Physical Chemistry deals with the geneial 
principles applied to all branches of theoretical chemistry, our aim 
has been to emphasize their application to inorganic chemistry, with 
which branch of the subject this series of text books is exclusively 
concerned To this end practically all the illustrations to the laws 
and principles discussed in Volume I deal with inorganic substances 

Again, there are many subjects, such as the methods employed in 
the accurate determination of atomic weights, which are not generally 
regarded as forming part of physical chemistry Yet these are sub- 



Vj, PREFACE. 

suffer by delay In the spring of 1 807, be was indocexj 
to offer the exposition of the principles herein contained 
in a course of Lectures, which wero twice read in 
Edinburgh, and once m Glasgow. On these occasion* 
ke was honoured with the attention of gentlemen, 
universally acknowledged to be of die first respectability 
for their scientific attainment*' moat of whom were 
pleased to express their desire to see the publication of 
the doctrine m the present form, as soon as convenient. 
Upon the author's return to Manchester he began to 
prepare for the press Several experiments required to be 
repeated, other new ones were to be mode, almott 
the whole system both in matter and manner was to be 
new, and consequently required more time for the 
composition and arrangement These considerations, 
together with the daily avocations of profession, have 
delayed the work nearly a year , and, judgmg from the 
past, it may require another year before it can be com- 
pleted In the mean time, as the doctrine of heat, and 
the general principles of Chemical Synthesis, are in a 
good degree independent of the future details, there 
can no great detriment arise to the author, or incon- 
venience to his readers, in submitting what is already 
prepared, to the inspection of the public 

MAY, 1808 



GENERAL INTRODUCTION TO THE SERIES, xx 

as this would render them unnecessarily bulky and expensive , rather 
has it been to contnbute eoncise and suggestive -accounts of the various 
topics, and to append numerous references to the leading works and 
memoirs dealing with the same Every effort has been made to render 
these references accurate and reliable, and it is hoped that they will 
prove a useful feature of the series The more important abbreviations, 
which are substantially the same as those adopted by the Chemical 
Society, are detailed in the subjoined list 

The addition of the Table of Dates of Issue of Journals (pp xix-xxvi) 
will, it is hoped, enhance the value of this series It is believed that 
the list is perfectly correct, as all the figures have been checked against 
the volumes on the shelves of the library of the Chemical Society by 
Mr F W Clifford and his staff To these gentlemen, the editor and the 
author desire to express their deep indebtedness 

In order that the series shall attain the maximum utility, it is 
necessary to arrange for a certain amount of uniformity throughout, 
and this involves the suppression of the personality of the individual 
author to a, corresponding extent for the sake of the common welfare 
It is at once my duty and my pleasure to express my sincere appre- 
ciation of the land and ready manner in which the authors have ac- 
commodated themselves to this task, which, without their hearty 
co-operation, could never have been successful Finally, I wish to 
acknowledge the unfailing courtesy of the publishers, Messrs Charles 
Griffin and Co , who have done everything in their power to render the 
work straightforward and easy 

J NEWTON FRIEND 

February, 1924 



PREFACE 

THIS volume is concerned with the first group of the Periodic System, 
and gives an account of the elements hydrogen, lithium, sodium, 
potassium, rubidium, caesium, copper, silver, gold, and their compounds 
It deals also with the radical ammonium and its principal derivatives 
The reasons for the inclusion of hydrogen among the elements of Group 
I are considered in the Introduction So far as the limitations of 
space have permitted, an attempt has been made to summarize the 
mam work done in this field of inorganic chemistry, and by means of 
numerous references it is hoped to give the reader easy access to the 
literature of those subjects of interest to him Many of the original 
papers mentioned have been consulted In addition, valuable in- 
formation has been afforded by Abegg and Auerbach's Handbuch der 
auotga/nuhen Chemie, by Thorpe's Dictionary of Applied Chemistry, 
by the Abstracts and Annual Reports of the Chemical Society, and by 
the Ckemisches Zentralblatt 

The author desires to express his hearty thanks to Dr F Challenger, 
FIG, for reading the proofs twice, and for making many valuable 
criticisms and suggestions , to Mr F W Clifford and his staff at the 
library of the Chemical Society for their kindness in checking the 
accuracy of many of the references , to Dr J Newton Friend, F I C , 
for numerous helpful suggestions respecting the text, and foi pre- 
paring the section on the atomic weight of lithium, and also the subject 
index and the table of contents , to Mr H F V Little, B Sc , D I C , 
for writing the sections on the other atomic weights, and for making 
the drawing of Morlcy's apparatus , to Dr O E Mott, QBE, F I C , 
for drawing the solubility-curves , to Dr A E H Tutton, F R S , 
for contributing the section on the isomorphism of the sulphates and 
selcnatcs of the alkali metals , and to the publishers for the caie 
bestowed by them on the production of the volume 

Although every effort to eliminate error from the text and from the 
references has been made, mistakes are inevitable, and the author 
would be glad if readers would notify to the publishers such errors as 
they may observe 

A T W 

February, 1924 



2 OK HEAT OR CALORIC 

quantities of heat m bodies of equal weight or 
bulk, or even the relative quantities, accu- 
rately ascertained, for any temperature, the 
numbers expressing those quantities would 
constitute a table of specific heats, analogous 
to a table of specific gravities, and would be 
an important acquisition to science Attempts 
of this kind have been made with very con- 
siderable success 

Whether the specific heats, could they be 
thus obtained for one temperature, would ex- 
press the relation at evefy other temperature* 
whilst the bodies retained their form, is an 
enquiry of some moment From the experi- 
ments hitherto made there seems httle doubt of 
its being nearly so , but it is perhaps more cor* 
rect to deduce the specific heat of bodies from 
equal bulks than from equal weights It is very 
certain that the two methods will not give pre- 
cisely the same results, because the expansions 
of different bodies by equal increments of 
temperature are not the same But before this 
subject can well be considered, we should first 
settle what is intended to be meant by the word 
temperature 



CONTENTS 

PAGE 

THE PERIODIC TABLE (Frontispiece) iv 

GENERAL INTRODUCTION TO THE SERIES vn 

PREFACE xi 

LIST OF ABBREVIATIONS xv 

TABLE OF DATES OF ISSUE OF JOURNALS xix 

CHAPTER I Introduction 1 

The Alkali Metals Copper, Silver, Gold Position of Hydrogen in the Periodic 
System The Ammonium Compounds 

CHAPTER II Hydrogen 10 

Occurrence History Preparation Manufacture Physical Properties Com 
pressibility Liquefaction Sohdification Occlusion by Metals Diffusion 
through Metals Chemical Properties Nascent Hydrogen Tnatomic 
Hydrogen The Hydrogen Ion Structure of Atomic Nuclei "Detection and 
Estimation Atomic Weight 

CHAPTER III Lithium 52 

Occurrence History Preparation Physical Properties Chemical Properties 
Lithium Ion Transmutation into Copper Atomic Weight Molecular 
Weight Position in the Periodic Table 

Compounds of Lithium Hydnde Halides and Oxyhahdes Compounds with 
Oxygen Sulphur Selenium and Chromium Lithium and Nitiogen Phns 
phorus Arsenic and Antimony Lithium Carbide and Carbonate C> amdc * 
Silicates and Boiates Detection and Fstimation 

HAPTER IV Sodium 81 

Occurrence H istory Preparation Physical Pi opei ties Chemical Properties 
Sodium Ion Applications Atomic Weight 

Compounds of Sodium Hydnde Hahdcs and Oxyhahdes Sodium Peroxide 
Sodium Hydi oxide Compounds with Sulphur Selenium Tellurium 
Sodium and Nitrogen Sodium Phosphorus Ai sonic and Antimony 
Sodium Carbonate I e Blanc Process Ammonia Sod i Process Flectio 
lytic Method Cyanogen Compounds Silicates and Borates 

Detection and > stimition 

UIIAPTJLU V Potassium 153 

Occurrence Histoiy Prepai ation Physical Properties Chemical Properties 

Potassium Ion Atomic Weight 
Compounds of Potassium Hydride Halides and Oxyhahdes Chlorate and 

Perchlorate Oxides and Hydroxide Compounds with Sulphur Selenium, 

and Tellurium Potassium and Nitrogen Potassium Nitrate Compounds 

with Phosphorus Arsenic Carbon, Silicon, and Boron 
Detection and Estimation 



4 ON TEMPERATURE 

rature, and then be raised to any other tem- 
perature, the additional quantities of heat 
received by each will be exactly proportioned 
to the whole quantities of that fluid previously 
contained in them This conclusion, though 
it may be nearly consistent with facts in gene- 
ral, is certainly not strictly true For, in 
elastic fluids, it is well known, an increase of 
bulk occasions an increase of specific heat, 
though the weight and temperature continue 
the same It is probable then that solids and 
liquids too, as they increase in bulk by heat, 
increase in their capacity or capability of re- 
ceiving more This circumstance, however, 
might not affect the conclusion above, pro- 
vided all bodies increased in one and the same 
proportion by heat , but as this is not the case, 
the objection to the conclusion appears of va- 
lidity Suppose it were allowed that a ther- 
mometer ought to indicate the accession of 
equal increments of the fluid denominated 
caloric, to the body of which it was to shew 
the temperature , suppose too that a measure 
of air or elastic fluid was to be the body, query, 
whether ought the air to be suffered to expand 
by the temperature, or to be confined to the same 
space of one measure ? It appears to me the 
most likely in theory to procure a standard 
capacity for heat by subjecting a body to heat, 



LIST OF CHIEF ABBREVIATIONS EMPLOYED 
IN THE REFERENCES 



ABBREVIATED TITLE 
Afhandl Fys Kern 
Amer Chem J 
Amer J Set 
Anal Fis Qaim 
Analyst 
Annalen 
Ann Chim 
Ann Chim anal 

Ann Chim Phy* 

Ann Mines 

Ann Pharm 

Ann Phys Chem 

Ann Physik 

Ann Physik Beibl 

Ann Set Umv Jaasy 

4.rbeiten Kaiserl QesiwdhetlA 

amte 

Arch exp Pathol Pharmak 
Arch Pharm 
4rch Sci phys nal 
AtttAcc Tormb 
Atti R Accad Lincet 
BA Reports 
Ber 

Bfr Deut physikal Ge 
Bot Zeit 
Bull Acad Set Cracow 

Bull Acad roy Belff 

Bull deBelg 
Bull Soc chim 
Bull Soc /rang Mm 
Bull Soc mm de France 
Bull US Oeol Survey 
Centr Mm 
Chem Ind 
Chem Newt 
Chem Weeltblttd 
Chem Zentr 
Chem Zett 
Gompt rend 

CreWa A nnalen 

Dingl poly J 
Drude's Annalen 
Electrocheni, Met Ind 



JOUBNAX 

Afhandlingat i Fysik, Kemi och Mineralogl 
American Chemical Journal 
American Journal of Science 
Anales de la Sociedad Espanola Fisica y Quimica 
The Analyst 

Justus Liebig's Annalen der Cheniie 
Annales de Ghmue (1719-1815, and 1914 +) 
Annales de Chimie analytique apphquee a 1'Industne, a 

1 Agriculture, a la Pharm acie, et a la Biologie 
Annales de Clamie et de Physique (Paris) (1816-1913) 
Annales des Mines 
Annalen der Phamiacie (1832-1839) 
Annalen der Physik und Chemie (1819-1899) 
Annalen der Physik (1799-1818, and 1900 +) 
Annalen der Ph \-3ik Beiblatter 
Annales scientifiques de 1 Umversitd de Jassy 

Aibeiten aus dem Kaiserhchen Gesundheitsamte 

Arcluv fur expenmentelle Pathologie und Pharm akologie 

Archiv der Pharmazie 

Archives des Sciences physique et naturelles, Geneve 

Atti delli Reale Accademia delle Scienze di Tormb 

Atti della Reale Accademia Lmcei 

British Association Reports 

Berichte der Deutschen chemischen Gesellschaft 

Benchte der Deutschen physika lichen Gesellschaft 

Botanische /eitung 

Bulletin international de 1 Acadernie des bciences de 

Cracovic 
Academie rovale de Belgique Bulletin de la Classe des 

Sciences 

Bulletin de la Socit6 chimique Belgique 
Bulletin de la Soeiet6 chimique de France 
Bulletin de la Socit6 fran9aise de Mmeialogie 
Bulletin de li Societc mineralogiquc de I nnce 
Bullufms of the United States Geological Survey 
Ccntralblatt fur Mmoralogie 
Die Chem che Industne 
Chemical News 
Cnormsch Wcekblad 
Chcmisches Zentralblatt 
Chcmiker Zeilung (Cothen) 
Coruptcs rcndus hebdornadaires des Seances clc I Acadume 

des Sciences (Pans) 
Chem sche Annalen fur die Freunde der Natuilchre, von 

L Crelle 

Dingier s polytcchnisches Journal 
Annalen der Physik (1900-1906) 
Flectrochemical and Metallurgical Industry 



ON 



of bodies for heat , that the efects am 
as t only to raise or depress the temperature a 
few degrees, when perhaps the whole mass- 
of heat is equivalent to two or three thousand 
such degrees > and that a volume of air sup* 
posed to contain 2005 of temperature being 
rarefied till it become 2000, or lost 5* of tem- 
perature, may still be considered as having its 
capacity invariable This may be granted if 
the data are admissible , but the true changes 
of temperature consequent to the condensation 
and rarefaction of air have never been deter* 
mined I have shewn, (Manchester Mem. 
Vol 5, Pt 2 ) that in the process of admit- 
ting air into a vacuum, and of liberating 
condensed air, the inclosed thermometer is 
affected as if in a medium of 60* higher or 
lower temperature , but the effects of instan- 
taneously doubling the density of air, or re- 
plenishing a vacuum, cannot easily be derived 
from those or any other facts I am acquainted 
with , they may perhaps raise the temperature 
one hundred degrees or more 1 he great heat 
produced in charging an air-gun is a proof of a 
great change of capacity in the inclosed air 
Upon the whole then it may be concluded, 
that the change of bulk in the same body by 
change of temperature, is productive of con- 
siderable effect on its capacity for heat, but 



LIST OF CHIEF ABBREVIATIONS EMPLOYED 
IN THE REFERENCES 



ABBEBVIATBD TITLE 
Afkandl Fys Kern 
Arner Chem J 
Amer J Set 
Anal Fia Qaim 
Analyst 
Annalen 
Ann Chim 
Ann Chim anal 

Ann Chim Phys 
Ann Alines 
Ann Pharm 
dnn Phya Chem 
Ann Physik 
Ann Physik Beibl 
Ann Sc% Umv Jassy 
Arbeiten Kaiserl Qesundhetls 

amte 

Arch exp Pathol Pharmak 
Arch Pharm 
4.rch Sci phys nat 
Atti Ace Torino 
Atti R Accad I meet 
BA Reports 
Ber 

Btr Dent physikal Ge* 
Bot Zeit 
Bull Acad Sci Cracow 

Bull Acad roy Belg 

Bull deBelg 
Bull Soc chim 
Bull Soc frang Mm 
Bull Soc mm de France 
Bull US Oeol Survey 
Centr Mm 
Chem Ind 
Chem Newt 
Chem Weekblad 
Chem Zentr 
Chem Zett 
Compt rend 

Crell 8 A nnalen 

Dingl poly J 
Drude?8 Annalen 
Electroch&n, Met Ind 



JOTJIINAJ* 

Afhandlingat i Tysik, Kemi och Mineralogl 

American Chemical Journal 

American Journal of Science 

Anales de la Sociedad Espanola Pisica y Quimica 

The Analyst 

Justus Liebig s Annalen der Chemie 

Annales de Chimie (1719-1815, and 1914 +) 

Annales de Chimie analytique apphqufe a 1' Industrie, a 

1 Agriculture a la Pharmacie, et a la Biologie 
Annales de Chimie et de Physique (Paris) (1816-1913) 
Annales des Mines 
Annalen der Pharmacie (1832-1839) 
Annalen der Physik und Chemie (1819-1899) 
Annalen der Physik (1709-1818, and 1900 +) 
Annalen der Ph\ sik Beiblatter 
Annales scientifiques de 1 Umversito* de Jassy 

Aibeiten aus dem Kaiserhchen Gesundheitsamte 

Archiv fur expenmentelle Pathologic und Pliarniakologie 

Archiv der Pharmazie 

Archives des Sciences pin sique et naturelles Geneve 

Atti della Reale Accademia delle Scienze di Tonnb 

A til della Reale Accademia Lmcei 

British Association Reports 

Benchte der Deutschen chemischen Gesellschaft 

Berichte der Deutschen physika lichen Gesellschaft 

Botamsche Zeitung 

Bulletin international de rAcadernie des Sciences de 

Cracovie 
Academie rovale de Belgique Bulletin de la Classe des 

Sciences 

Bulletin de la Societe chimique Belgique 
Bulletin de la Socie'te chimique de France 
Bulletin de la Soci^to fran9aise de Mineialogie 
Bulletin de Ix Socitc mmeralogique de ti nice 
Bulletins of the United States Geological Survey 
Ccntralblatt fur Mine ralogie 
Die Chem che Industrie 
Chemical News 
Cnomisch Weekblad 
Chemisches Zontialblatt 
Chemiker Zeitung (Cothen) 
Comptes rcndus hebdomadaires des Seances dc 1 Acackmie 

des Sciences (Pans) 
Chem sche Annalen fur die Freunde der Naturlehre von 

L Crelle 

Dingier s polytcchnisches Journal 
Annalen der Physik (1900-1906) 
Flectrochemical and Metallurgical Industry 



8 Oa* TBMPEEATT7B.B. 

two liquids will agree in giving the same mean 
temperature upon being mixed as above. 

In the present imperfect mode of estimating 
temperature, the equable expansion of mer- 
cury is adopted as a scale for its measure. 
This cannot be correct for two reasons, 1st 
the mixtere of water of different temperatures 
is always below the mean by the mercurial 
thermometer , for instance, water of S2 and 
212 being mixed, gives 119* by the thermo- 
meter , whereas it appears from the preceding 
remarks, that the temperature of such mixture 
ought to be found above the mean 122* , 2d 
mercury appears by the most recent experi- 
ments to expand by the same law as water , 
namely, as the square of the temperature from 
the point of greatest density The apparently 
equal expansion of mercury arises from our 
taking a small portion of the scale of expan- 
sion, and that at some distance from the free- 
zing point of the liquid 

From what has been remarked it appears 
that we have not yet any mode easily practi- 
cable for ascertaining what is the true mean 
between any two temperatures, as those of 
freezing and boiling water , nor any thermo- 
meter which can be considered as approxima- 
ting nearly to accuracy 

Heat is a very important agent in nature , it 



LIST OF CHIEF ABBREVIATIONS 






rvii 



ABBREVIATED TITLE 
Sitzwgsber K Akad W*s& 

Wien 

Sei Prod Hoy Dubl 8o& 
Techn Jahresber 

Trans Amer Electrochem 

Sot- 

Trans Chem Soc 
Trans Inst Mm Eng 
Trav et Mem du Bureau 

intern des Poids et Mes 
Verh Oes d*ut Naturforsch 

Aerzte 
Wted Annalen 

Wtssenschafll Abhandl 

pfys tech Reichsanst 
Zeitsch anal Chem 
Zeitsch angew Chem 
Zeitsch anorg Chem 
Zeitech Chem 
Zevtsch Chem Ind Kolloide 



EUTetrochem 
Zeitsch Kryst Mm 
Zeitsch Nahr Genuss m 

Zeitsch physikal Chem 

Zeitsch physiol Chem 
Zeitsch was Photochem 



JOUBNAI, 
Sitzungsbenchte der Komghch bayerisohen Akademie 

der Wissenschaften zu Wieru 
Scientific Proceedings of the Royal I>ablm Society 
Jahresbencht uber die Leistmjgen der Chemischen 

Technologie 
Transactions of the Amenoan Eleotroohemioal Society 

Transactions of the Chemical Society 

Transactions of the Institution of Aiming Engineers 

Travaxtx et Memoires du Bureau International des Poids 

et Mesuies 
Verhandlung der Gesellschaft deutscher Natarforsoher 

und Aerzte 
Wiedennann's Annalen der Physik und Chemie (1877- 

1899) 
Wissenschafthche Abhandlungen der physikahsch tech 

nisohen Eeichsanstalt 
Zeitschnft fiir analytische Chemie 
Zeitschrif t fur angewandte Chemie 
Zeitschnft fur anorganische Chemie 
Kritische Zeitschnft fur Chemie 
Zeitschnft fur Chemie und Industrie des Kolloide (con 

turned as Kolloid Zeitsohnft) 
Zeitschnft fur Elektrochemie 
Zeitschrn*t fur Krystallographie und Mineralogie 
Zeitschnft fur Untersuchung der Nahrungs undGenuss 

mittel 
Zeitschnft fur physikahsche Chemie, Stochiometrie und 

Verwandtschaftslehre 

Hoppe Seyler's Zeitschnft fur ph^ siologische fhemie 
Zeitschnft fur wissenschafthohe Photographic, Photo 

physik, und Photochemie 



1C 



is as the square of the tempcratitre from thci 
respective freezing points Water very maail 
accords with this law according to the presen 
scale of temperature, acid the little denatioi 
observable is exactly of the sort that ougfc 
to exist, from the known error of the equa 
division of the mercurial scale. By prosccut 
ing this enquiry I found that the mercuna 
and water scales divided according to the prin- 
ciple just mentioned, would perfectly accord, 
as far as they were comparable , and that the 
law will probably extend to all other pure 
liquids, but not to heterogeneous compounds, 
as liquid solutions of salts. 

If the law of the expansion of liquids be such 
as just mentioned, it is natural to expect that 
other phenomena of heat will be characteristic 
of the same law It may be seen in my Essay 
on the Force of Steam (Man Mem Vol 5, 
Part 2 ) that the elastic force or tension of 
steam in contact with water, increases nearly 
in a geometrical progression to equal incre- 
ments of temperature, as measured by the com- 
mon mercurial scale y it was not a little sur- 
prising to me at the time to find such an ap- 
proach to a regular progression, and I was then 
inclined to think, that the want of perfect 
coincidence was owing to inaccuracy in the 
division of the received thermometer, but 



TABLE OF DATES OF ISSUE OF JOURNALS. 

FOR the sake of easy reference, a list is appended of the more 
important journals in (lnoriolo<:i(,il order, giving the dates of issue of 
their corresponding series and volumes In certain cases the volumes 
have appeared with considerable irregularity, in others it has occa- 
sionally happened that volumes begun in one calendar year have 
extended into the next year, even when this has not been the general 
habit of the series To complicate matters still further, the title-pages 
in some of these latter volumes bear the later date a most illogical 
procedure In such cases the volume number appears in the accom- 
panying columns opposite both years In a short summary of this kind 
it is impossible to give full details in each case, but the foregoing 
remarks will serve to explain several apparent anomalies 



Year 


Amer 
J Sci 


I s 


Ann 
Mm 


'4 


fj 


Gilbert's 
Annalen 


fl 

fig 


Phil 
Mag 


Phil 
Tians 


f g 


1800 




(1)32-35 








4-6 




5-8 


90 




1 




36-39 








7-9 




8-11 


91 




2 




40-43 








10-12 




11-14 


02 




3 




44-47 








13-15 




14- 1 7 


93 




4 




48-51 








16-18 




17-20 


94 




1805 




52-55 








19-21 




20-23 


95 




6 




56-60 








22-24 




23-26 


9b 




7 




61-64 








2^-27 




26-29 


97 




8 




b5-68 








28-30 




29-32 


98 




9 




69-72 








31-33 


(1) 1* 


33 34 


99 




1810 




73-76 








34-36 


2 


35, 36 


100 




11 




77-80 








37-39 


3 


37, 38 


101 




12 




81-84 








40-42 


4 


39 40 


102 




13 




85-88 








43-45 


5 


41, 42 


103 




14 




89-92 








46-48 


b 


43, 44 


104 




1815 




93-96 








49 51 


(2)1 


45, 46 


105 




16 




(2) 1-3 








52 54 


2 


47,48 


106 




17 




4 6 


1,2 






55 57 


<3 


49 50 


107 




18 




7-9 


3 






58 60 


4 


51 52 


108 




19 


(1)1 


10-12 


4 






61 6^ 


5 


53 54 


109 






i 


















1820 


2 13-15 


5 




1^-3 


64 66 


6 


55 56 


110 




21 


3 16-18 


6 




4-b 67 69 


7 


>7 58 | 111 




22 


4, 5 


19-21 


7 


1,2 


7-9 70 72 


8 


59, 60 


112 




23 


6 


22-24 


8 


3 6 


10 12 


73-75 


9 


61, 62 


113 




24 


7,8 


25-27 


() 


7-10 


13 1 > 


76 


10 


63, 64 


114 


1 2 


1825 


() 


28-30 


10 11 


11-14 


16 18 


a 


11 


bj 66 


115 


3-5 


26 


10 11 


U-33 


12 13 


15-19 


19 22 


~ gr> 


12 


67, 68 


116 


6-8 


27 


12 


34-36 


(2)1,2 


20-23 


23 26 


O^ 


1 i 


(2)1 2 


117 


9-11 


28 


H, 14 


37-39 


3 4 


24-26 


27-30 


g tn 3 


14 


3 4 


118 


12-14 


29 


15 16 


40-42 


5,6 


27-30 


31-34 


* 


15 


5,6 


119 


15-17 



* Fust senes known as Bulletin de J harma^ic, 

XIX 



12 ON TEMFEEAT0ES 

expansion as the permanently elastic fluids 
I had formerly conjectured that air expand 
as the cube of the temperature from absolut* 
privation, as hinted m the essay above-men 
tioned, but I am now obliged to abandoi 
that conjecture 

The union of so many analogies in favoui 
the preceding hypothesis of temperature u 
almost sufficient to establish it, but one remark 
able trait of temperature derived from expe 
nments on the heating and coohng of bodies 
which does not accord w ith the received scale 
and which, nevertheless, claims special con 
sideration, is, that a body in cooling loses heai 
in p? open lion to its excess of tcmpci atine aboit 
that of the cooling medium , or that the tern 
perature descends in geometrical progression 
in equal moments of time Thus if a body 
weie 1000above the medium , thctimcs in cool 
ing from 1000 to 100, from l(X)to lO,and from 
10 to 1, ought all to be the same 1 his, 
though nearly, is not accurately true, it we 
adopt the common scale, as is will known* 
the times in the lower intervals of temperature 
are found longer than in the upper, but the new 
scale proposed, by - 1 orU IP the lower de- 
grees, and lengthening the higher, is found 
perfectly according to this remarkable 1 iw of 
heat 



TABLE OF DATES OF ISSUE OF JOURNALS 



JJ 








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CO 
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True 

equal 
inter- 
vals of 
tempe- 
lature. 



=s 

8$ 

18 

8 

1 

18 
~ 

4* 



** 

101 
118 
122 

13* 



X62 

I 7 X 

182 
191 

aia 
412 



NEW TABLE OF TEMPERATURE 



76643 
0748 

8 
8 

93063 
97108 

10 1373 
105378 
109483 

11 3588 

l 179 

690 

13 ooo) 

134*13 
138218 
1423*3 

14 6418 
'5i33 
i54 6 38 




'9 9793 
H 084^ 



3 V" 
336 399 



TABLE OF DATES OF ISSUE OF JOURNALS 



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't-* co os"o r-i (N co"-^ n t>- o oo 06 o r>q 

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OrHf^lCO'HH "5COl->.OOCJS OrH(McO'' 



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cococococo cococococo t^.t-.i>i>.r. r-t>-*N^t>t>. oooooooooo ooooooooco 
oo oo oo oo oo oo 



16 ON TEMPERATURE. 

being 12% but below 32 and above 212% the 
differences become more remarkable 

The 2d and 3d columns are two series, the 
one of roots, and the other of their squares 
They are obtained thus > opposite 32, m the 
first column, is placed in the 3d, 72% bemg 
the number of degrees or equal parts m Fahren- 
heit's scale from freezing mercury to freezing 
water , and opposite 212* in the first is placed 
252 in the 3d, being 212 + 40% the number 
of degrees (or rather equal parts) between 
freezing mercury and boiling water The 
square roots of these two numbers, 72 and 
252% are found and placed opposite to them 
in the second column The number 8 4853 
represents the relative quantity of real tem- 
perature between freezing mercury and free- 
zing water, and the number 158743 repre- 
sents the like between free/ing mercury and 
boiling water , consequently the difference 
7 3890 represents the relative quantity betvvcc n 
freezing water and boiling \\ater, and 7 ^8 ( >(> 
18 410j represents the quantity corres- 
ponding to each interval of K) Bv iddmg 
41()j successively to 8 18 > I, or subtracting it 
from it, the rest of the numbers in the column 
are obtained, which aic of course in uithmc 
tical progression Ihe numbers in the Id 
column are all obtained by squaring those of 



TABLE OF DATES OF ISSUE OF JOURNALS 



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l^l<-.CO-OOS OSCTOOrH 

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18 OSF TEMPER AT0RE 

not for this increase Not however to over-rate 
the effect, I have taken it only at 1 7, making 
the number 108*, 3 in the 4th column, 1 10* 
in the 5th, and the rest of the column is cor- 
rected accordingly The numbers in this 
column cannot well be extended much beyond 
the interval from freezing to boiling water, for 
want of experiments on the expansion of glass 
By viewing this column along with the 1st, the 
quantity of the supposed error m the common 
scale may be perceived , and any observations 
on the old thermometer may be reduced to 
the new 

The 6th column contains the squares of the 
natural series I, 2, 3, &c representing the 
expansion of water by equal intervals of tem- 
perature Thus, if a portion of water at 
42 e expands a quantity represented by 2H l ), at 
the boiling temperature, then at 52 it will he 
found to have expanded 1, at 62, 4 parts, &c 
&c Water expands by cold or the ab.tiac- 
tion of heat in the same way below the point 
of greatest density, as will be illu^tritcd \\lun 
we come to consider the absolute cxjnnsion of 
bodies Ihe apparent greatest duisity too 
does not happen at 39%3 old se ik , but ibout 
42, and the greatest real density is it or nnr 
36 of the same 

The 7th column contains a series of num- 



A TEXT-BOOK OF 
INORGANIC CHEMISTEY. 



VOL II 
THE ALKALI-METALS AND THEIR CONGENERS 



CHAPTER I 
INTRODUCTION 

THE first group of the periodic system 1 includes hydrogen (H=l 008) , 
the alkali-metals lithium (Li=694), sodium (Na=23 00) potassium 
(K=39 10), rubidium (Rb=85 45), and ccesium (Cs=132 81) , and the 
metals copper (Cu=63 57), silver (Ag=107 88), and gold (Au=1972) 
The inclusion of hydrogen in Group I was suggested by Mendelceff, 2 
but the arrangement has been subjected to much adverse criticism, 
many chemists preferring to class it with the halogens as the first 
member of Group VII An account of the arguments advanced by both 
schools of thought is given on pp 6 to 8 The close resemblance of 
the compounds formed by the interaction of ammonia 3 and acids 
to the metallic salts, and especially to the salts of potassium, makes it 
desirable to include these compounds in a description of the derivatives 
of the elements of Group I They contain the umvalcnt ladical 
ammonium, NII 4 (p 8) 

The Alkali-Metals 

The name alkali is derived from the Arabic Al kaljun, meaning the 
ashes of sea-plants and land plants Prior to the Ficnch Revolution 
the carbonates of sodium and potassium wcie manufactured by lixi- 
viation of these ashes , and, on the isolation of sodium and potassium 
(pp 82 and 152), the name was employed to denote the group of which 
they arc typical 

The inclusion of iron, cobalt, nickel, and certain other metals m 
Group VIII 4 enables the alkali met ils lithium, sodium, potassium, 
rubidium, and cesium to be plaeed m then natural position as a sub- 
group of Group I of the periodic system, in juxtaposition to the related 
sub group containing copper, silver, and gold (p 3) This arrangement 

1 See Frontispiece 2 Mcncleleeff, Annalen, 1872, Suppl 8, 133 

3 This series, Vol VI 4 Ttus series Vol IX 

VOL II 1 



20 ON TEMPERATlfEE* 

tbose numbers do not differ from the table 
just referred to, which was the result of ac- 
tual experience, so much as 2* in any part j a 
difference that might even exist between two 
thermometers of the same kind 

The 9th column exhibits the force of the 
vapour of sulphuric ether in contact with 
liquid ether , which is a geometrical progres- 
sion, having a less ratio than that of water 
Since writing my former Essay on the Force 
of Steam, I am enabled to correct one of the 
conclusions therein contained , the error was 
committed by trusting to the accuracy of the 
common mercurial thermometer Experience 
confirmed me that the force of vapour from 
water of nearly 212% varied from a change of 
temperature as much as vapour from ether of 
nearly 100 Hence I deduced this general 
law, namely, " that the variation of the force 
of vapour from all liquids is the same for the 
same variation of temperature, rtcLoiMni; from 
vapour of any given force " But I now find 
that 30 of temperature in the lower part ot 
the common scale is much more than HO m 
the higher and therefore the vapours ol ether 
and water are not subject to the same change 
of force by equal increments of temperature 
The truth is, vapour from water, ether and 
other liquids, increases in force in geometn- 



EOTRODUCTION 3 

production of strongly basic hydroxides of the formula M OH, dis- 
tinguished by their great solubility in water, their very caustic 
nature, and their complete stabjhty at high temperatures According 
to Hackspill, 1 no action on ice can be detected for sodium at 98 C , 
for potassium at 105 C , for mbicJium at 108 C ? and for esestu^n 
at 116 C These results indicate that rise m the atomic weight of the 
metals is accompanied by a development in the electropositive character 
They neutralize all acids, forming salts of the type M X m which the 
metal is univalent The chemical activity of the members of the series 
increases with their atomic weights in the order lithium, sodium, 
potassium, rubidium, and caesium 

Despite the close resemblance between the members of the alkali- 
group, important differences in character must be noted The pro- 
perties of certain salts of lithium and sodium present a marked contrast 
to those of the corresponding salts of potassium, rubidium, and csesium 
While the normal carbonates and phosphates of all other metals are 
insoluble in water, those of the alkali-metals dissolve, but the carbonate 
and phosphate of lithium are characterized by their comparatively 
slight solubility (pp 74 and 76) In this respect lithium displays more 
analogy to the alkahne-earth-metals than to its companions m Group I 
A similar difference in character between the first member of a group 
and the succeeding members is displayed m other instances 2 Potassium, 
rubidium, ^nd caesium differ from lithium and sodium m forming 
comparatively insoluble chloroplatmates and primary tartrates, and 
deliquescent carbonates Lithium and sodium, members of the two 
short periods, possess the general group-character, whereas potassium, 
rubidium, and caesium, belonging to long periods, display almost 
complete homology 

Copper, Silver, and Gold 

The metals eopper, silver, and gold occupy corresponding positions 
in the three long periods of the periodic system, and furnish i connecting 
link between the high melting and non volatile metals mekel, palladium, 
and platinum e>f Gioup VIII 3 and the readily fuse el vol itile metals 
/me, cddmium, <md mercuiy of Group II 4 Then leljtionsmp to the 
ilk ill met ils, cspe e uilly to sodium, is analogous to that of /me , e ulmium, 
uul meuury to m loiusiiun These in ilogics aie illusti it( el by UK 
sul)]omed t ible of itomic weights 

Na2JOO Mg= 2432 
Ni 58 68 Cu= ()e3 57 Zn G5 57 
Pei-=10()7 Ag--10788 Cd = 112K) 
Pt-=1952 Au=1972 Hg=200 

I lie itomic volumes uul eoelheients of expansion displ ly a sinnl ir 
relationship 

Some ol the physical cemstaiits erf the coppei gioup ue cited m the 
ippciukd table 

1 lUdsjull Ami, Ckitii Pliy^ 19H, (8J 28 OH 

Compno catbon (tins sonos, Vol V ) t,hicmum (this scnos Vol Til ) and fluorine 
(thisHenob Vol VIII ) 

3 Ihis senes Vol IX 

4 Ibid Vol III 



22 ON EXPANSION, 

sible to have a portion of liquid remaining 
in contact with the vapour 

The 10th column shews the force of va- 
pour from alcohol, or rather common spirit of 
wine, determined by experiment in the same 
way as the vapour of water Tbig is not a 
geometrical progression, probably because the 
liquid is not pure and homogeneous I sus- 
pect the elastic fluid m this case is a mixture 
of aqueous and alcoholic vapour. 



SECTION 2 

EXPANSION BY HEAT 

One important effect of heat is the expan- 
sion of bodies of every kind Solids are least 
expanded, liquids more, and elastic fluids 
most of all The quantities of increase m 
bulk have in many instances been determined, 
but partly through the want of a proper ther- 
mometer, little general information has been 
derived from particular experiments UK. 
force necessary to counteraet the expansion 
has not been ascertained, execpt in the ease 
of elastic fluids, but there is no doubt it is 
very great The quantity and law of expan- 
sion of all permanent elastic fluid* have already 



INTRODUCTION 5 

are not decomposed by heat, but cupnc oxide is converted into cuprous 
oxide, and the elimination of the oxygen from the oxides of silver and 
gold can be effected without the application of excessive heat 

The cupric compounds, CuXjj, show a marked resemblance to those 
of the metals of Group II and to those of other metals characterized by 
their bivalency, an example being the similarity of constitution and iso- 
morphism of cupric sulphate with the sulphates of magnesium and 
zinc, and with the ous sulphates of iron, nickel, cobalt, and manganese 
All these sulphates combine with those of the alkali metals to form 
double salts analogous in constitution and crystal form Isomorphism 

n 
is also a feature of the corresponding carbonates, MC0 3 , chlorates, 

M(C1O 3 ) 2 ,6H 2 O , and bromates, M(BrO 3 ) 2 ,6H 2 O 

The auric compounds, AuX 3 , are related to the corresponding 

m 

derivatives of such tervalent metals as aluminium, A1X 3 , and indium, 
m 

InX 3 , another instance of the close connexion subsisting between the 
valency of a metal and the typical characteristics of the compounds 
derived from it Three series of oxides are given below, the com- 
pounds formed from each member being similar m character to the 
corresponding compounds of the same series 



Na 2 
Sodium 

MgO 

Magnesium 



Ag 2 

Silver 

ZnO 

Zinc 



Cu 2 

Cuprous 

CuO 

Cupric 



Au 2 O 

Aurous 

FeO 

Ferrous 



T1 2 

Thallous 

HgO 

Mercuric 



A1 2 3 
Aluminium 



Fe 2 3 
Ferric 



Au 2 3 
Auric 



T1 2 3 
Thalhc 



Chiomium, 1 manganese, 2 and iron 3 also exemplify the alteration in the 
ehaiaetei oi compounds occasioned by a change of valency In the 
first scats even the heavy metals have a very positive and basic char- 
acter, silver oxide and thallous oxide being strong bases, and cuprous 
oxide and aurous oxide having a more pronounced basic character than 
the cori espondmg highci oxides The oxides oi the third seues are 
slightly leuhe, i c haraetc nstie xssoeiated with the somewhat metalloidic 
chu letci oi the leiviknt metals liom which they are derived The 
hydiogin oi ilummmm hydroxide, A1(OH) 3 , and oi auuc hydroxide, 
Au(OlI) 3 , resembles that oi bone aeid, 13(O11) 3 , 111 being leplaeeable by 
ilk ill met Us with ioimation oi compounds ot the type Al(ONa) 3 
Indium oxide, ln 2 O 3 , ls ^ soluble m alkalis, but does not appear to 
ioiin i deimite compound 

Ihe ilk ill metals aie dLslm^m^lx d iiom the heavy metals oi the 
coppci #ioup by the Ioimation oi veiy stable hydi oxides and caibonates 
Coppei hydroxide, Lu(OlJ) 2 , is veiy easily deeomposed into the oxide 
and w itu, and the hydroxides oi silvei and gold have not been isolated 
The behaviom oi the eaibonales is similai , thus, silver earbonate is 
lapidly deeomposed at iJOO C , with evolution of carbon dioxide 4 

Ihe c ompounds of the alkali metals with weak amoris, such as O" 01 



1 HUH acnes, Vol VII * Ibid , Vol VIII 

4 Joulm, Ann Chun Phys , 1873, [4], 30, 200 



Ibid , Vol IX 



24 OJff EXPANSION 

rest j in this case if temperature be adde* 
uniformly, the liquid will appear to descent 
with a velocity uniformly retarded to a certan 
point, there to be stationary, and afterwards t< 
ascend with an uniformly accelerated velocity 
of the same sort as the former For, & 
the velocity with which the liquid expands 11 
umfornorly accelerative, it must successively pas* 
through all degrees from to any assigned 
quantity, and must therefore in some mo- 
ment be the same as that of the vessel* and 
therefore, for that moment, the liquid must ap- 
pear stationary previously to that time the 
liquid must have descended by the third pro- 
position, and must afterwards ascend, by the 
2d but not uniformly Let the absolute 
space expanded by the liquid at the moment 
of equal velocities be denoted by 1, then that 
of the vessel in the same time mubt be <J , be- 
cause the velocity acquired by an uniformly 
accelerating force, is such as to mo\e a body 
through twice the space in the same time It 
follows then that the liquid must have sunL 
1, being the excess of the expansion ot the 
vessel above that of the liquid Again, Jet 
another portion of temperature equal to the 
former be added, then the absolute expansion 
of the liquid will be 4, reckoned trom the com- 
mencement, and the expansion of the vessel 



INTRODUCTION, 7 

strong reason for not placing it in Group VII , since it indicates that the 
first member of the halogen group must be more electronegative than 
fluorine, the most electronegative of all the elements So convinced 
was M endeleeff as to the antithesis between hydrogen and the halogens, 
that in his last speculations 1 as to the possibility of the existence of 
still undiscovered elements he discusses a hypothetical member of the 
seventh group with an atomic weight of about 3 

In 1872 Newlands 2 associated hydrogen with chlonne, because 
chlorine can replace hydrogen in organic compounds without material 
alteration in the character of the substances, and because he considered 
that its atomic weight shows it to be the lowest member of the halogen 
group 

Masson 3 has given a number of reasons for including hydrogen in 
Group VII A summary of his views is appended 

1 Hydrogen is umvalent 4 

2 The molecule of hydrogen, like that of a halogen, is diatomic, but 
the molecule of an alkali-metal is monatomic 

3 The gaseous character and very low boiling-point of hydrogen 
The alkali-metals are solid at ordinary temperatures, and increasing 
atomic weight is accompanied by a fall in boiling-point 

4 The average difference between the atomic weights of the adjacent 
members of a horizontal series is 3, so that by placing hydrogen at the 
head of Group VII it is brought next to helium with the atomic weight 
4, the first member of the zero group 5 Since the mean difference 
between the atomic weights of successive members of the same group 
is 16, this arrangement brings hydrogen into line with fluorine, 
the difference of their atomic weights being 18, and that of hydrogen 
and lithium 6 

5 Both the liquid and solid forms of hydrogen lack metallic pro- 
perties , 6 thus, the liquid is a non conductor of electricity 

6 The mutual leplaceabihty of hydrogen and chlorine in organic 
compounds, first noticed by Dumas It should be observed that in 
substitution in inorganic compounds hydrogen displays a much closer 
analogy to the alkali metals than to the halogens, as is illustrated by 
the acids and the corresponding salts (p 6) 

Moissan 7 found that the hy dudes of lithium, sodium, potassium, 
rubidium, and c t sium are non conductors of electricity, and therefore 
cannot be regarded as alloys He considered that in these compounds 
li\dioui has a mctalloidic character, and that it is not comparable 
with the metals, an argument against its inclusion in Gioup 1 8 

Both the eleetroehemical eharactei oi the element (p C) and its 
beh ivioui as in JMOI^IMK substituent (ut &upia) seem to indicate the 
desirability oi including it in Group I , the airangement adopted in 

1 Mi ud( lu II Pfonulluu* 1UOJ 15 145-151 ( 1 luni (Ju\tt 1904 i 138 

NowlandH ('In in N(w*> 18% 72 W3 
J MasHon ibid J!SJ 

4 UK umvaleney of hydrogen cannot bo icgaidcd as in argument foi picfonmg 
GJioup VII to ( 1 ioup I A more cogi nt reason la the non vanant character of its valency, 
in which it IB akin to the alk ih metals 

5 Una series Vol 1 

It should be rioted that hydrogen resembles tho metals in crystallrzing rn the cubrc 
system (p 20) It also has the power of displacing certain metals from solutions of 
their salts (p 26) 

7 Moissan, Compt rend , 1903, 136 591 

8 Compare Brauner Ghem News, 1901, 84, 233, and lithium hydride (p 59) 



26 es 

by another portion it will be 5, by another 
&c , as before 

The truth of the above proposition may I 
otherwise shewn thus 

Let 1, 4, 9, 16, 25, &c., represent the ai 

solute expansions of the liquid, and p, $ j 

3 jo, 4p, 5 p, &c, those of the vessel b 

equal increments of temperature, then 1 j 

42 p, 93 p, 16 4 p, 25 5 p, &c., wi 

represent the apparent expansion of the 1 

quid , the differences of these last quantity 

namely 3 p, 5p, 7 p, 9 p, &c , forr 

a series in arithmetical progression, the com 

mon difference of which is 2 But it is dc 

monstrated by algebraists, that the difference 

of a series of square numbers, whose roots an 

m arithmetical progression, form an anthrne 

tical progression, and that the common differ 

ence of the terms of this progression is equa 

to twice the square of the difference of the 

roots Hence, as 2 = twice the square of 1 

we have the above arithmetical stncs ^~p, 

5p, &c , equal to the differences of a series 

of squares, the common difference of the roots 

of which is 1 

Now to apply these pr.nc.ples solid bodus 
are generally allowed to expand uniformly 
within the common range of tempt nturc it 
all events the quantity is , small compared 



INTRODUCTION 9 

solution of sodium or potassium hydroxide, 5 per cent of ionized 
ammonium hydroxide molecules being present in a tenth-normal solu- 
tion, as against 91 per cent of ionized potassium hydroxide molecules 
in a solution of similar concentration The quaternary ammonium 
bases or tetra alkylammomum hydroxides are organic derivatives of 
ammonium hydroxide formed by replacement of the four hydrogen 
atoms of the ammonium radical by alkyl-groups An example of these 
compounds is tetramethylammomum hydroxide, N(CH 3 ) 4 OH Their 
degree of lomzation in aqueous solution sis proved by the electee con- 
ductivity, which is comparable with that of the hydroxides of sodium 
and potassium They are thick liquids of strongly alkaline reaction, 
and in chemical character closely resemble these bases It is reasonable 
to assume that if ammonium hydroxide could attain the same con- 
centration in solution as a quaternary ammonium base, it would exhibit 
similar electric conductivity The dissimilarity of ammonium hydroxide 
in this respect is due to its decomposition, mainly into ammonia and 
water 

The comparatively feeble basic reaction of an aqueous solution of 
ammonia is traceable to this tendency to decomposition, and not to lack 
of lomzation of the ammonium hydroxide x In the neutral reaction of 
its salts with strong acids, such as the chloride and nitrate, and in the 
alkaline reaction of those with weak acids, exemplified by the carbonate 
and cyanide, the radical ammonium displays complete analogy with the 
metals potassium and sodium This fact constitutes a strong argument 
in favour of the view that ammonium hydroxide, so far as it is present 
m an aqueous solution of ammonia, is to a great extent ionized 

The formation of an ammonium amalgam, the general character of 
the ammonium salts, the existence of the monohydrate, the electro- 
chemical properties of aqueous solutions of ammonia, and the similarity 
of the quaternary ammonium bases to the hydroxides of sodium and 
potassium, justify the consideration of the ammonium compounds in 
conjunction with those of the alkali metals 

1 Conipaio bthlubuch and Ballauf, Bei , 1921, 54, [B], 2825 



0IT EXPANSION, 



to 213 > tibaa it may be inferred that the _. 
expansion of water from greatest density 
n& is TT f lts v l ume > 3 ^at the absolute] 
expansion of water is determinate this wayj 
without knowing either at what tempmtuwq 
its density is greatest, or the expansion of tbtl 
vessel containing it I 

Cor 3 If the expansion of any vessel 
can be obtained > then may the temperature 
at which water is of greatest density be ob* 
tamed, and vice vtrsd This furnishes us 
with an excellent method of ascertaining both 
the relative and absolute expansion of all 
solid bodies that can be formed into vessels 
Capable of holding water 

Cor 4 If the apparent expansion of water 
from maximum density for IHO" were to be 
equalled by a body expanding uniformly, its 
velocity must be equal to that of w ater at 90\ 
or mid-way And if any solid body be found 
to have the same expansion as water at 10* 
from max density , then its expansion for 180* 
must be | of that of water, JU Btcaubc m 
water v is as t, &c 

By graduating several glass th< rmomcter 
vessels, filling them with water, expiring 
them to different kmpenturcs, and compirmg 
results, I have found the appannt expansion 
of water in glass for every 10 of the eommon 



HYDROGEN 11 

density of an atmospheric gas the less rapidly does the amount of it 
present diminish with increase in the height of the atmosphere 

History Hydrogen was known to the alchemists as a product of the 
interaction of acids and metals, and was called *' inflammable air " 

The suggestion first made by John Joachim Becher (1635-1682), that 
combustion is essential to chemical change, was further developed by 
Georg Ernst Stahl x (1660-1734) StahTs theory involved a number 
of assumptions, which admit of the following summary 

1 All combustible substances are compounds 

2 Burning eliminates from these substances a constituent common 
to them all, " phlogiston " (<A.oyi<TTos, burnt) 

3 The degree of combustibility increases with the proportion of 
phlogiston present 

4 Substances like phosphorus, carbon, sulphur, and many organic 
bodies contain a large proportion of phlogiston 

5 Metals also contain phlogiston in varying proportions They are 
to be regarded as compounds of this substance with the calx left after 
their combustion 

6 The reconversion of metallic calxes into the metal by heating 
with carbon, gases, and other substances in modern parlance the 
reduction of the oxide is the result of a combination of the phlogiston 
of the reagent with the calx 

The phlogiston theory remained unrefuted for about fifty years In 
1772 Rutherford discovered nitrogen, and in 1774 Priestley isolated 
oxygen (" dephlogisticated air ") Between the years 1772 and 1788 
Lavoisier made numerous investigations into the nature of combustion, 
his results leading him to the conclusion that there is no essential 
difference between respiration, combustion, and calcination 

In 1781 Cavendish and Watt proved water to be produced by the 
combustion of hydrogen A repetition of their experiments in 1783 
by Lavoisier and Laplace indicated that water contains 1 volume of 
oxygen and 1 91 volume of hydrogen The interaction of red hot 
iron and steam, with liberation ol fiec hydrogen and production of a 
calx ol iion, was also observed by Lavoisier 

The diseoveiy ol the compound nature of water by Cavendish and 
Watt, ind the results obtuned by Lavoisiei and his coadjutois in then 
invc slig itions oi the qu intit itivc composition oi this substance, rendeied 
the |)lilnjis|oii theoiy untenable It hid played a useful part as the 
liist step to pi ic ing the science of ehcmistiy on a lational basis, and it 
is inUicstmg to note that both Priestley and Cavendish icmamed 
I >lil ji^li i -, to the end 

Preparation The choice oi i method ioi the piepaiation of hydrogen 
in the liboritoiy is decided by the degree oi punty required in the gas, 
but by suitable me ins the pioduct obtained by the mtei action of a metal 
and in acid can be sulhciently punlied for ordinary use 

1 One ol the best methods Ioi the preparation of pure hydrogen 
is the electrolysis of water containing sulphuric acid 01 potassium 
hydroxide to ujm il the conductivity The acid or alkali plays an 
impoitant part in the process, as indicated in the schemes 



(a) 11 2 SO 4 =2I14-SO 4 " , H 2 O+bO 4 "=H 2 S0 4 +O 

(6) kOH=K+OH', K+H 2 0=KOII+H, 2OH'=H 2 0+O 

1 Stahl Fundamenta Chymiae, Nonmbergae, 1723 



SO O 

for 1804, Dr. Hope has given a paper OB tb 
contraction of water bjr heat m low tempera* 
tures {See also Nicholson's Journal, VoL 12 } 
In this paper we find an excellent history of 
facts and opinions relative to this remarkable 
question in physics, u ith original experiments 
There appear to have been two opinions res- 
pecting the temperature at which water obtains 
its maximum density, the one stating it to 
be at the freezing point, or 32* , the other at 
40 Previously to the pubhcat ion of the above 
essay, I had embraced the opinion that the 
point was S2, chiefly from some experiments 
about to be related Dr Hope argued from 
his own experiments in favour of the other 
opinion My attention \\as again turned 
to the subject, and upon re examination 
of facts, I found them all to <oneur in giving 
the point of greatest density it the temperature 
36, or mid-way between the points lormcrly 
supposed In two letters msirUd in \iehol- 
son's Journal, \ ol M and 11, I ciukivour- 
ed to shew that I)i Hopes expuiments 
supported this conclusion and no other I 
shall now shew that my o\\n c\|urnnc nts on 
the apparent expansion ot \viUi in cliilerent 
\cssels, coincide with them in est iblishmg the 
same conclusion 

I he results of mv experiment*, \\ithout 



HYDROGEN 13 

alkali and with an oxidizang-solution such as acidified potassium 
permanganate To remove arsenic, Reckleben and Lockemann 1 
recommend passing the gas through a saturated solution of potassium 
permanganate or a 5-10 per cent solution of silyer nitrate, or over 
cupnc oxide, for use on the n 'ii if,i< luii'itr scale they advise em- 
ploying a solution of bleachmg-powder 

It is noteworthy that pure zinc decomposes dilute acids very slowly, 
but that addition of a few drops of a solution of cupnc sulphate or 
platinum chlonde greatly augments the velocity of the reaction A 
similar effect is produced by amalgamating the metal In both instances 
the acceleration is due to electrolytic action, the copper and platinum 
being deposited on the zyac (compare method 2, p 12) 

For any metal the power of decomposing water and acids is deter- 
mined by two factors the potential of the metal must be more negative, 
and its solution-pressure must be higher, than the corresponding con- 
stants of the hydrogen evolved from the water or dilute acid 

Victor Meyer and von Reckhnghausen 2 have pointed out that 
contact with hydrogen materially increases the tendency of potassium 
permanganate to evolve oxygen, so that in washing with this reagent 
there is risk of introducing oxygen as an impurity They explain the 
slow absorption of hydrogen by potassium permanganate by assuming 
oxidation to hydrogen peroxide, which is then decomposed by the 
permanganate with evolution of oxygen 

An improved type of generator for producing hydrogen from zinc 
and an acid has been described by Edwards 3 It is said to be superior 
to the ordinary Kipp apparatus m rapidity of furnishing a supply of 
hydrogen free from air 

5 Solution of zinc, aluminium, and tin in concentrated caustic 
alkalis evolves hydrogen, with formation of the zmcatc, alummate, ind 
stannatc of the alkali metal 

Zn+2KOII-H 2 +ZnO,K 2 , 
2Al-h6KOII=3H 2 +Al 2 3 ,3K 2 O , 
Sn+4KOII=2lI 2 +SnO 2 ,2K 2 O 

Hydrogen is evolved from aqueous solutions of strong icducmg- 
agents, such is chiomous salts, 4 potassium cobiltocyinidt, 5 chloro 
molybdenum e hloiule (J (Mo 3 Cl c ), inel trom all i (\\ M j \ uits with a 
reduction potent id higher thin tint oi hydiogeii The velocity oi the 
giseous evolution is e onsiele i ibly uoeleiiteel by idditum e>l imely 
ehvieleel pi it mum 01 pall ulium, espeeiilly iiom chromous ehloneie 7 

7 Jiiuno 8 h is prep<ueel hulio << n by igit itmgircm iilmgs with \\ itci 
situntcel with eiibem elioxiele, the operation listing 20-10 hours 

I<c + lI 2 + C0 2 =II 2 +FeC0 3 

Manufacture of Hydrogen-- Sever 1! methods ire employed m the 
prcpai itiem of hydiogen on the large scale 

1 Rcc kl( h( n and locluminn Zdhch anqcw Chan J ( )08 21 4?3 
Victor M( y< r and von I Mr 18%, 29 2540, 2828 

n TMlwiids J hid I'M/ ' I 'I ' I 0(>l 

4 Bcrtlulot Com fit tend 1S08 127 24 

5 Petois P/iatm CenltathalU 1898 39 ()0 r > Minchot and Htrzocr Bcr 1900 33 1742 
Mutlnrmnn and Nagi I ti(r 1808 31 2012 

7 Peters /Milwh phynkal Chem 1898 26 19^ 

8 Bruno Bull Soc chim , 1907, [4] 1 661 



32 Ojr EXPANSION 

a ^ jT or rather more than 18 times a* much j 
therefore the mean velocity of the expansion 
of water (which is that at 90, or halfway) it 
18 times more than that of glass, which 19 
equal to the expansion of water at 42* j this 
last mast therefore be ^ of the former $ con- 
sequently water of 42* has passed through 
TJ. of the temperature to the mean, or ^ of 
90 = 5% of new scale = V of old scale, above 
the temperature at which it is absolutely of 
greatest density This conclusion however 
cannot be accurate > for, it appears from the 
preceding paragraph that the temperature 
must be below 38 The inaccuracy arises, I 
have no doubt, from the expansion of glass 
having been under-rated by Smeaton , not from 
any mistake of his, but from the peculiar 
nature of glass Rods and tubcb of glass are 
seldom if ever properly anneakd > bcncc they 
are in a state of violent energy and often 
break spontaneously or with a slight scrateh 
of a file tubes have been found to expand 
more than rods, and it might be expected that 
thm bulbs should cxjnnd more still, because 
they do not require annealing , hence too the 
great strength of thm fihsi, its bung less brit- 
tle, and more susceptible of sudden transitions 
of temperature I rom tin ibo\c experiments 
it seems that the expansion dac to glass, such 



HYDROGEN 15 

results by Dr George C Simpson in Captain Scott's last Antarctic ex- 
pedition (1910-1912) In a modified form 1 of tins process, the hydride 
is mixed with Sodium hydrogen carbonate, boric acid, or soda-bme, and 
heated at 80 C Namias 2 has pointed out that the use for balloons of 
hydrogen evolved from sulphuric acid and cast iron involves damage 
to the envelopes, the arsine and phosphine present becoming oxidized to 
arsenic acid and phosphoric acid respectively, and these acids e&ert a 
corrosive action on the material of the gas-bag Jonssen 8 has given a 
useful summary of the methods employed in the preparation of gas for 
balloons 

3 Jaubert 4 described a process involving the use of "hydrogemte," 
a mixture of silicon, calcium hydroxide, and sodium hydroxide At red 
heat it reacts in accordance with the equation 

Si+Ca(OH) 2 +2NaOH=Si0 4 Na 2 Ca+2H 2 

This method is also employed for balloon-gas 

4 At red heat calcium carbide reacts with water-vapour, liberating 
hydrogen and carbon dioxide 5 

CaC 2 +5H 2 0=CaO+2C0 2 +5H 2 

The carbon dioxide is absorbed by hme The yield is excellent, the 
hydrogen produced is very pure, and is well adapted for heating and 
lighting, and for filling balloons 

5 Lavoisier's work on the composition of water showed that steam 
reacts with iron at 150 C , liberating hydrogen and forming ferroso- 
fernc oxide, Fe 3 4 

3Fe+4H 2 ^^ 4H 2 +Fe 3 4 

Deville 6 investigated the reaction, and proved it to be reversible The 
proportion of hydrogen in the equilibrium mixture is greatest at 800 C , 7 
a highei temperature shifting the equilibrium to the left, and causing 
reduction of the iron, oxide Deville believed the composition of the 
solid phase to correspond with the formula Fc 4 O 6 , but later work by 
Premier 8 leaves it still undecided between Fe,FcO, FeO,Fe 3 O 4 , and 
Fc,Fe,0 4 

The interaction of steam and iron takes place m three stages 9 

(1) Dissocivlion of steam 

II 2 O -^211+0 

(2) Combination of the nascent oxygen with the iron to form feirous 
oxide 

Fe+O -FeO 

Aftei one hour at 350 C this reaction becomes peiccptible 

1 Bunbcigd Bock ami W 1117 Ocrmun Pali tit 1910 No 21S257 

Nainns 1 ImluHtna Chinnca 1907 7,257 
JniiHHcn Clnm Wukblnd l ( )ll 8 <>25 
4 Tan be it R(v gin Chun 1010 13 141 357 

Sium MB and 1 Intake derma n PuUnt 1910 No 220480 
Devillo Cowpt rani 1870 70 1105 1201 71, JO Annalen 1871 157, 71 

7 Iittirmann / Ca^hilt Hfhluvy 1896,39,187,204 

8 J'Kumi //Littch phywlal Cheni J904 47 -J85 

9 Jineml J Weitof Scotland Iron and NUdlntf 1910, 17, 06 J lion and Steel I nst 
1909n,172 Tncnd, Hull and Jiiown, Tianv Chun Hoc 1911 99 909 Chaudron 
Compt rend , 1914, 154 237 Jmcnd The Corronon of Ir on and &ted (Longmans 1911) 
chap 111 1 urthci details are given m this series Vol IX , Part II 



54 

wi*erais Smcaton makes it more. The 
was made of tbc patent malleable sine of Hod* 
son and Sylvester Perhaps it contains a por- 
tion of tin, which wtH account for the devia- 
tion 

Lead expands ^ of its bulk for 180*j 
water therefore expands about 5} times as 
much , this gives 90 -r 51 16*1 of new scale 
= 13 of old scak , whence 49* 13* = 36*, 
as before 

From these experiments it seems demon- 
strated, that the greatest density of water is 
at or near the 36 of the old scale, and 37* or 
38 of the new scale and further, that the 
expansion of thin glass is nearly the same as 
that of iron, whilst that of stone ware is }, 
and brown earthen ware | of the same 

The apparent expansion of mercury m a 
thermometncal glas* for 18O* I find to be O163 
from 1 I hat of thm ghss may IK slated at 
0037 = 17^, uhich is rather Us than iron, 
7 * T Consequently the real txpuiMon ol mer- 
cury from 32 to 'JllTib iqml to thi sum <>t 
these = 0'2 or ^ DC I uc makes it, oih >h, 
and most other authors make it less b<e uist. 
they have all underrated the expulsion ot 
glass Henec \\L clcn\c this propottion, 
0163 180 0057 41 ntarh, \\lnch t \- 
presses the effect of the expansion of jjlissi on 



Expressed as functions of -, the formulae are 



C pv=Q 99918 + (0 00081613)/t; + (0 000001220)/fl 2 , 
50 C pv = I 18112 + (0 0010505)/a + (0 000001015)/?; 2 , 
100 C pv = I 36506 + (0 0012450)/i; + (0 000001240)/i? 2 



The effect of pressure on hydrogen is represented graphically m 
fig 1 (p 18), the product pv being plotted 3 against the pressure p 
Neon and helium resemble hydrogen m being less compressible than 
Boyle's law demands 4 

Travcrs 5 observed that at ordinary temperature the expansion of 
hydrogen without doing work is attended by rise of temperature, 
indicating that under these conditions it behaves as an " ultra perfect " 
gas , at 80 C ind 200 atmospheres its effusion without doing work is 
unaccompanied by cilorific effect, a property chaiactenstic of a perfect 
gas J)c war 6 found thit at 200 C hydrogen begins to assume the 
charictci oi an imperfect g%s, expansion without external work being 
attended by i 1 ill in temper iturc Landolt 7 gives the diffusion 
coclhoiont of hydrogt n with rt spcct to oxygen as 677 sq cm sec at 
C and 7(>0 mm 

Ilydiogcn is ibsoilxd by wood charcoal, and Kaspcr 8 has shown 
that 1 ( ( oi this siibstiiuc at C and 130 mm ibsoibs 1 5 e e , at 
the s ime tcrnpc r iture iud 1800 mm it ibsorbs 117 ee 

Lchkldt () #ives ioi the clectioehenucil cqiuvilcnt of hydrogen 
96,500 coulombs oi 01" il IMHIUML cc oi gis pci coulomb The 

1 Raykigh Phil 7/ws !<)()! 196 205 1<)02, 198 417 J<)0 r > 204 3 r >l Ptoc 
Ray Hoc 10() r ) [A| 74 44(> 

Holborn Ami Physik 1<)20 [4J 63, (>74 

J 1% 1 is taken from this suus Vol 1 29 In that volume compai alive details 
of the behaviour of othti g iscs umki picsauic arc given 

4 Compare tins s< ucs Vol I Part II 

6 fravcrs Phil Maq 1901 [0] I 411 
G Dcwir Ghem Ntws 1896 73 40 

7 Landolt Bornstdn and Mt ycrhoffer Tabellen 3rd ed Berlin 1905 375 

8 Kasper W%(d Annalcn 1881 12 520 

y Tehfddt Phil Mag 1908 [6] 15 614 

VOL II 2 



4? 



HYDROGEN 17 

The behaviour of hydrogen at very low pressures has been in- 
vestigated by Rayleigh * At about 1 5 mm it obeys Boyle's law, and 
continues to do so within very narrow limits up to l0 mm 

Holborn 2 has studied the isothermal^ of hydrogen at C^ ** 
50 C , and 100 C , the pressure limits being 20 and 100 atnio- 
spheres As unit of pressure hs selected that of a column of mercury 
having a height of one m&tre at C under the normal gra\it\, 
g=980 665 cm -sec 2 , and the unit of volume was th^ volume of the gas 
under this pressure Within the limits of experimental error, amounting 
to a few parts in ten thousand, the isotherms for 50 C and 100 C were 
linear , whilst the deviation of that for C did not exceed one part per 
thousand The results obtained can be expressed m the following 
formulae 

C pv=Q 99918+0 00082094p + 0000003745r 2 , 
50 C pv=l 18212+0 00089000^, 
100 C pv=l 36506 + 00091400p 



$$ CUT EXFAHSiOff, 

th&ae observations, it is remarkable bow 
those liquids approximate to thtf law of 
expansion observed in water and mercury. 
Few authors have made experiments 00 thftpt 
subjects, and their results in several instance* 
am incorrect My owa investigation* haw 
beea chiefly directed to water and mercury j 
but it may be proper to give the result* of my 
enquiries en the other liquids as far as they 
have been prosecuted 

Alcohol expands about ? of its bulk for 
180, from 8 to 172 The relative expan- 
sions of this liquid are given by D* Luc 
from 32 to 212, but the results of my expe- 
riments do not seem to accord with his Ac- 
cording to him alcohol expands 35 parts for 
the first 90% and 45 parts for the second 9CT 
The strength of his alcohol was such as to fire 
gun-powder but this is an indefinite test 
From my experiments I judge it must have 
been very weak I find 1000 parts of alcohol 
of 817 $p gravity at the temperature 50* be- 
came 1079 at the temperature 170 of the 
common mercurial scale at 11O the alcohol 
is at 10S9, or half a division below the true 
mean When the sp gravity is 86,1 find 1000 
parts at 50 become 1072 at 170 , at 1 ID* the 
bulk is 1035 -f, whence the disproportion of 
the two parts of the scale is not so much 




HYDROGEN 



Croullebois l has determined the refractive indices at ordinary tem- 
perature and pressure for the C, E, and G lines of the solar spectrum 
Merton and Barratt 2 have studied the spectrum of hydrogen 

Liquefaction The fact that hydrogen cannot be liquefied solely by 1 
pressure engendered a belief in the impossibility of its liquefaction 
In 1877 Cailletet 3 allowed hydrogen at a pressure of 280 atmospheres 
to expand adiabatically to the pressure of the atmosphere, thereupon 
the temperature dropped below 200 C , and a fine, transient mist of 
hydrogen appeared Olszewski 4 confirmed Cailletet's results, and by 
the aid of liquid air as a cooling-agent Dewar 5 effected complete 
liquefaction He cooled the gas to 205 C at a pressure of 180 
atmospheres, and then allowed it to expand to atmospheric pressure, 
collecting the condensed hydrogen in a double walled vacuum-flask, 
silvered to retard absorption of heat On the initiative of Travers 6 
and of Olszewski, 7 the principle of Lmde's air-hquefier has been utilized 
m the construction of a machine for the liquefaction of hydrogen on the 
large scale, the gas being first cooled to 200 C 

In the liquid state hydrogen is colourless and transparent, and a non- 
conductor of electricity Although its surface-tension is low, being -% 
that of water and \ that of liquid air, it has a distinct meniscus and drops 
well It obeys the law of Dulong and Petit, its specific heat 8 being 
about 6 Its atomic volume at the boilmg-pomt is 14 3, and its 
density is 07, or T V of that of water 9 Its densitv at 252 83 C and 
745 52 mm is 07105 10 The latent heat of evaporation at the boiling- 
point is 123 1 cal n Dewar 12 gives the boiling point at atmospheric 
pressure as 252 5 C , or 20 5 abs Olszewski 13 gives 252 6 C , 
and for the critical temperature 240 8 C , and for the critical pressure 
13 4-15 atmospheres The value calculated by Goldhammer 14 for the 
critical density is 02743 Travers and Jacquerod 15 have tabulated 
the values obtained by them for the vapour-pressure 

1 CronlUboiH Ami Ckim PJiys 1870 [4] 20 136 

M( rton and Barratt, Phil Trans , 1922, [A] 222, 369 

1 Cailhtot Compt ntut 1877 85,851 Ann Chim Phys 1878 [5] 15 132 
4 O|q/<wsJi ( 1 ontf>t nml 1885 101 2*8 

r Dtwu 7W///s ('/tun hoc IS08 73 528 Ohem Niwi 1000 81 1% For a general 
iromml of UK hqiuf i< lion of KRS< H H< f Husseins Vol I JO to 42 

IiLV<is /'//// Mn(\ 1 ( )OI [(>! I 411 /Jdlvh pJn/ulal Chew 1001 37 100 
Tin httuh/ oj M/sf s (Ma< millan LOOI) 

7 <)ls/< \\sli inn C/IIHI /V///s 100* [7| 29 2SO JmU Acad bn ( 1 )<irf>u 1002 1)10 
!<)(){ 211 

* I)<WIT l>n>c Hot/ Hot 1901 [A] 68 360 
J l)(war 7'n/^s Chew hoc 1898 73 528 
Au^ushn I//// /////s// I01 r > |l| 46 410 
Dcwii l>tot Roy MM 1005 [A] 76 325 
J)ewai ibid 1 001 (A] 68 44 300 

l ()|s/(\vsJi !)))!( s AnnnliH 1005 17 OS(> Bull \C(i<l bet t'uicnu I008 57 r > 
( oldlmnnui Adl^ch j>/n/ultil Hunt lOIO 71 577 
1 iav( IH and luqiunxl ('/MM Newt 1002 86 (>1 



Jg OH EXPANSION 

iqigt per cent water, it is fair to infer front 
the above that a thermometer of pure alcohol 
would IB no apparent degree differ from one 
of mercury m tbe interval of temperature from 
50" to no* But when we consider that the 
relative expansions of glass* mercury and alco- 
hol for this interval, are as 1, 5i and 22 re- 
spectively, it must be obvious that tbe inequa- 
lity of the expansion of glass in the higher 
and lower parts of the scale, which tends to 
equalise the apparent expansion of mercury, 
has little influence on alcohol, by reason of its 
comparative insignificance Hence it may be 
presumed that a spirit thermometer would be 
more equable m its divisions than a mercu- 
rial one, in a vessel of uniform expansion 
This it ought to be by theory, because the 
point of greatest density or congelation of 
alcohol is below that of mercury 

Water being densest at %", and alcohol at 
a very remote temperature below, it was to 
be expected that mixtures of these would he 
densest at intermediate temperatures, and those 
higher as the water prevailed, thus we find thr 
disproportion, so obscrvabk in tht c xpansion 
of water, growing greater ind greater in the 
mixtures as they approach to pure witc r 

Water saturated with common salt expands 
as follows 1000 parts at 32 become 10 >0 



HYDROGEN 21 

variation of the experiment is to fill the tube with nitrogen, which is 
superior to air because of its inertness towards hydrogw , on heatmg 
it in an atmosphere of h> drogen, diffusion inwards cimses a rise in the 
pressure of the gas within the tube 

Sieverts * observed that at high temperatures copper-wire, iron-wire, 
nickel, cobalt, and platinum 2 occlude hydrogen, but that silver does J 
not (p 294) He found that diffusion through copper begins at 640 C , 
through iron 3 at 300 C , and slowly through nickel 'at 450 C , but thfct 
there is no diffusion through silver at 640 C Sieverts's 4 results also 
indicate the insolubility of the gas in cadmium, thallium, zinc, lead, 
bismuth, tin, antimony, aluminium, gold, tantalum, and tungsten, but 
Heald 5 states that most freshly precipitated metals absorb hydrogen 

Metals permitting the passage of hydrogen at a red heat, but not of 
other gases, may be regarded as having the character of a semi-permeable 
membrane Palladium is the most permeable of these metals, Graham 6 
having found that a sheet with a thickness of 1 mm allows 327 c c to 
pass per sq cm in one minute at 265 C , and 3992 c c at 1062 C 
The fact that the velocity of diffusion, although dependent on the 
pressure, does not decrease proportionally with it, is cited by Winkel- 
mann 7 as an argument in support of his theory of the atomic condition 
of hydrogen occluded by palladium 8 

Many metals occlude hydrogen, and there is a close connexion 
between their power of occlusion and their magnetic properties 9 At the 
ordinary temperature, elements with a specific magnetic susceptibility 
exceeding 09X10" occlude hydrogen readily, but, as a general rule, 
other elements lack this capacity 

The amount of hydrogen occluded by metals depends on the pressure, 
and diminishes with use of tcmpciature It is also affected by the 
physical condition ind previous history of the metal Mond, Ramsay, 
and Shields 10 found that at ordinary temperature and 1 to 4 6 atm 
the absorption oi Ii\ diojn n by palladium black is 873 vols , and between 
these limits is independent oi the pressure For spongy palladium 
the absorption is 852 vols , and loi palladium foil previously heated to 
redness, <s M> \ ols Most of the oc c hided gas is evolved in vacuum at the 
ordin uy ttmpci ituie ind the icsiduil 2-8 pei cent at that of boiling 
suJphm At chfl( i cut st i#cs <>t the oc elusion the he at evolved is the same, 
bung 4 $70 ( d loi each gi mi oi hydiogin At oidmaiy tempeiatmes 
spongy platinum ibsoibs 110 vols oi hydiogin, vanations ot pressure 
b(t\v7(ii()5 ind J r > ilni producing hi tic effect on the amount occluded 

1 Suvdts /til^/i i>/n/tll (lion l ( )()7 60 I2<) With lisped to aid il comput 
Miyd UK! Allmi\< i Ha 1 ( )()S 41 }0i>2 hi< vdls ind Hi^ciuckti Bu 1901)42 JJb 
/n/sr/< /;////s//f// < Inn, I <><><> 68 I l r > 

MompiH Ni list m<l hsMii,. (ollin</o \tuhnthlui 1002 J 4t> <*utlw.i ind M usch 
l$u !<)!<) >2 |Bj IU>S Sdnnidl ind lml< /nlvh /V///s// 1 ( )J1 8 152 

' ( OIIIIUM Ndiisl UK! I<MSIM^, !<>< at Sdinndi nid 1 IK kt lo< at 

Suvdts ind Knunhhur 7>o I ( )IO 43 S<) J /ntvh i>/aj^l<il Clu tn 1910 74 
277 hi(vits /jdlvh tit I lux In w 1 ( )1() 16 707 SicvutH and lioignci, Bar 1911 
44 2i ( M 

lit ild /'/<// rial Anlvh 1 ( M)7 8 (> r ><) 

' ( ith mi rnn Iwi/ Sor 1S(,7 15 227 J 8(>h 16 U2 lb<><) 17 212 500 

7 Wmlvdiiiami />/'/'/' s \nnttlui 1 ( )()I 6 104 U unsay Mill May 1894 38 20b 

8 S this sc IKS \ol I \ I* nt I 17b 

o I) I* hiiuili / rht^utl ( Inm 1 ( )19 23 Ibb 

> Mou<l Runsiy and him Ids Proc Roy SOL 1897 62,290 ZetfccA atiotg Chen, 
16, J25 ^Lihch jjhyttiLal Chun , 1898 25,657 



40 W EXPANSION 1 

$6* or below $ whence it accords with the 
same kw as water and mercury* I find thrt 
even the glacial sulphuric acid, or that oi 

I 78 sp. gravity, which remains congealed at 
45% expands uniformly, or nearly like the 
other, whilst it continues liquid* 

Nitric actd, sp gravity 1 4O, expands abort 

II per cent from 32 to 212 ; the expansion 
is nearly of the same rate as that of mercury, 
the disproportion not being mom than 27 to 
28 or thereabouts The freezing point of acid 
of this strength is near the freezing point of 
mercury 

Muriatic acid, sp gravity 1 137, expands 
about 6 per cent from 32* to 2! 2, it is 
more disproportionate than mtnc ac*d, as 
might be expected, being so largely diluted 
with water The ratio is nearly 6 to 7 

Sulphuric ether expands after the rate of 
7 per cent for 180 of temperature I ha\c 
only compared the expansion of this liquid 
with that of mercury from (>() to W In 
this interval it accords so nearly with mercury 
that I could perceive no sensible difference in 
their rates It is said to free/c at 46* 

From what has been observed it may be 
seen that water expands lcv> than most other 
liquids, yet it ought to be consult red <is hav 
ing m reality the greatest rate of expansion 



SYDROGEtf 22 

Palladium-black contains both amorphous and crystalline palladium, 
and the proportion of each constituent and the sorptive capacity of the 
substance vary with the conditions of preparation At low temperatures 
the sorptive capacity of palladium-black depends on the temperature at 
which sorption begins When a sample saturated with hydrogen at 
100 C is cooled in the gas, it sorbs more hydrogen From 100 to 20 C 
the sorptive capacity decreases slightly, and increases continuously 
from 20 to 190 C By heating palladium-black it is possible to 
increase the proportion of the crystalline variety * The relationship 
between the occlusive power of palladium for hydrogen and the actmfy 
of the metal for catalytic hydrogenation has been investigated by 
Maxted 2 

The occlusion of hydrogen by palladium decreases very rapidly with 
rise of temperature from 100 to 600 C , more slowly up to 800 C , and 
only very slightly between 800 and 1500 C 3 

The effect of " poisons " on the occlusion of hydrogen by palladium 
has been studied by Maxted 4 Hydrogen sulphide diminishes the 
occluding power of the metal, each atom of sulphur rendering almost 
exactly four atoms of palladium incapable of occluding the gas, while 
the remaining palladium occludes normally de Hemptinne 5 found 
that carbon monoxide deprives palladium of its sorptive power for 
hydrogen at low temperatures Paal and Hartmann 6 proved that 
carbon monoxide inhibits the activity of palladium for the catalytic 
reduction of sodium picrate, and observed 7 mercury to exert a similar 
effect on palladium hydrosols 

A volumetric method for the estimation of hydrogen, either alone or 
m gaseous mixtures, is based by Paal and Hartmann 8 on sorption by 
colloidal palladium, a simple gas-pipette being employed 

The ocelusion of hydrogen by various metals has been investigated 
by Graham, 9 and ilso by Neumann and Stremtz 10 Their results are 
appended in tabulai ioim, and give the volume of hydrogen under normal 
conditions soibed by one volume of the metal It is noteworthy that 
their observation x . ulmu silver is not confirmed by the more recent 
work of Sic v( its 



Silvc i (wiu ) 
Silvc i (powdc i ) 
Aluminium (loil) 
( oh ill (udu( (d) 
C opjK i (wnc ) 
Coppc i (icduc cd) 
lion (wiu ) 
lion (in ill(<ibl( ) 



21 


Iron (redueed) 


4-19 2 


()<)! 005 


M i#iu sium 


1 4 


1127 


Nickel (uduced) 


17-18 


r ><) 1 5 5 


(Jold (k il) 


048 


5 
() 4 S 


(iold (j)iecipit itcd) 
Lc id (Inscd) 


37-16 
11-0 15 


1() 


/nu 


liaces 


57 S 







1<)21 119 1120 

Client 1 ( )11 88 lot 451 

I'M** H5 I0 r >0 I ( )20 117 12bO 
//s*// (turn J8 ( )8 27 24<) 
MHO 43 -4$ 

1'HH 51 711 Jial intl Skyci, ibid 
1010 43 24 J coinpaic Biuncl 



Maxtcd M 22 r > 12HO 
1 Snviits /(itvli i>ln/vl 
1 Mi\tcd 7ws < 1 lnni *S 

cl( HimpliniK /M/sr/i /> 
< Paal uid Haitmiiin M> 

7 Pul uKlHutmiMM lit i 1'HH 51 711 Jial intl Skyci, ibid 1743 

8 Pail uul Hulininii liu 1010 43 24 J coinpaic Biuncl Cheni Zeit , 1910, 
34 I tl t 



(jtahim Phil Mat/ 18()(> LH 3 2 4()1 r>()r> J874 W 47 324 
10 Neumann and StiuiiU, Potjtj Annalcn 1839 46, 431 



42 OH 

indicates it to be very low, or much lowtr 
than fe commonly apprehended, Perhaps ft 
may hereafter be demonstrated that the inter* 
val of temperature from 32* to 2158* of Fahren- 
heit, constitutes the 10th, 15th, or 20th inter- 
val from absolute cold Judging from analogy, 
we may conjecture that the expansion of solids 
is progressively increasing with the tempera* 
ture , but whether it is a geometrical progres- 
sion as elastic fluids, or one increasing as the 
square of the temperature, like liquids, or as 
the 3d or any power of the temperature, strll 
if it be estimated from absolute cold, it must 
appear to be nearly uniform, or in arithmetical 
progression to the temperature, for so small 
and remote an interval of temperature as 
that between freezing and boiling water The 
truth of this observation will appear from the 
following calculation let us suppose the inter- 
val in question to be the 15th , then the real 
temperature of freezing water will br 1?520 , 
the mid-way to boiling 2610% and boiling 
water 2700, reckoned from absolute cold 



Dif 



= 196 



= 225 



D.f 



= 2744 



-304 



I 



= 337* 



HYDROGEN 25 

to the ready inflammability of mixtures of the gas and air During the 
war it was found possible to develop the production of helium within 
the British Empire on a commercial basis, and to employ this gas as a 
safe substitute for hydrogen in connexion with warfare in the aor l 
Within certain limits it has been found practicable to utilize non- 
inflammable mixtures of helium and hydrogen for this purpose SIK& 
mixtures have the advantage of possessing a greater lifting power than 
pure helium Ledig 2 found that a jet of helium with more than 14 per 
cent of hydrogen can be ignited in air, but tha| in balloon practice 
from 18 to 20 per cent of hydrogen can be employed, as the mixture 
does not burn with a persistent flame With a proportion of hydrogen 
exceeding 20 per cent , the mixture is unsafe for use in war aeronautics 

von Wartenberg and Sieg 3 found that the union of hydrogen and 
oxygen between 600 and 1000 C is attended by the formation of a 
considerable proportion of hydrogen peroxide, this product rapidly 
decomposing into water and oxygen Ozone is formed by condensation 
of a part of the oxygen The velocity of decomposition of the ozone 
being less than that of the hydrogen peroxide, a greater proportion of 
ozone is found in the mixture Fiesel 4 states that with moist hydrogen 
and oxygen the reaction is bimolecular, and that hydrogen peroxide 
may be an intermediate product , with the absolutely dry gases the 
reaction is termolecular 

The combination of hydrogen and nitrogen under pressure was 
effected by Le Chatclier 5 in 1901, but owing to an explosion the method 
was not worked commercially In 1905 the subject was fuither studied 
by Ilaber and van Oordt, 6 who found that at red heat the velocity of 
combination is too slow to admit of measurement, and that at higher 
temperatures the amount of ammonia formed is small, either on account 
of rapid chssoeiation or because the reaction-affinity is small 

In 1910 Ilabci 7 lound that in presence of metallic osmium 1 volume 
of mtiogen unites with 3 volumes of hydiogcn at 550 C and 200 
atmospheics, the yuld being 8 pci cent of the mixed gases On the 
manufac tilling sc ile , osmium can be replaced by the less costly uiamum, 
uid a continuous cnculition method is employed, with a temperature 
about 500 C 8 Any ( u bon monoxide pic sent in the h\<h<^<n should 
be u mo\ c (1 y 

Methods loi pioelu<m<r unmoni i horn its elements undei the in 
line nee oi the silenl elisehu^e inci oi the cleetiie spaik have not pioved 
commc ic i illy sue e c ssinl J() 

r l he olhei numlxis o! Ihe intie)Len ^;ic>up elo not ioim hyehides by 

1 ( 1 ompai( M< I < mi in '/'WHS Chun tfo( 1920, 117 923 

I ( du / I HI! /< n</ ( Inm l<)20 12 10<)S 

von Wut< nix 1^ nid Sn ha l<)20 53 |B| 21<)2 

In s< I /utvh i>lu^tlnl <hun 1<)2I 97 J 5h 

UUiitdui / nn<h r<ttuil l ( )()l No II J950 Couipt nnil 1917 164 58b 

Halx r and v in Ooidt /ul^rh anoxj ( Jnni 1905 44 J4J 

llalx i /H/V/, 1'ltlttothtni 11)10 16 2-11 

(ornpiK ( laiidt (ontpl tuid 1 ( )22 174 ()81 

I iinh S< dioni nid \i\tr\i / \nut ( JIUH >Sor 1 ( )22 44,738 
10 (otnpiK Mulld uid ( (is(nb(i^(i Mulish JWuih JS79 Mo J4bl 1879 No 1592 
Young Bnlitk Patent 1SSO No 1700 Sotute d A/ott German Patent No 17070 
Nithul (juniaii Patent No < ) r ) r > i2 West Deutsche I hoimuphosph ilwerkc, German 
Patent NOB L572S7 md 17<)JOO (Jonanofl trench Patent No 308585 Hooper US 
Patent No 791194 ( 1 asscl German latent No 175480 Bnnci and Mettlcr, Compt 
rend , 1907, 144 094 Ddvies Zeitsch phystkal Ohem , 1908 64 657 



03? EXPAOTIOK, 






certain temperature ; then 1000 cubic iachcp 
of the same will become 1003 by the same 
temperature 

The folio wing Table exhibits the expansion 
of the principal subjects hitherto determined, 
for 18<yof temperature, that is, from 32* to 
212 of Fahrenheit The bulk and length of 
the articles at 32* are denoted by 1 



SOLIDS 

Brown earthen ware..-, 
Stpae ware *...,... -. 
Glass rods and tubes. . 

bulbs (thin) .. 

Platinum . 

Steel , 

Iron ,.. ., 

Gold , 

Bismuth .,. .. ... 

Copper ... .. .. . 

Brass 

Silvu . ...... 

Fine Pewter . . . 

Tin 

ILtid 

Zinc 



LIQUIDS 

Mercury .. 
Water . . ". . 
Water sat with salt .. 
Sulphuric add 
Muriatic Acid .. .. 
Oil o^ tuipentine . . 

Ether 

Fixed oiU 

Alcohol .. 

Nitric acid 

FLASTIC FLUIDS* 

asesofall kinds .. 



EXPANSION 



In bulk 



0025=,^ 



00*4= 



, 



00 M^ 



0200= 



t Shuaton 



0110= 



370 -s j 
* Lllitott J Borda 



TI* 



hi length* 



t 
t 

t 

t 

t 

* 

t 
t 



rr, 



>> 

1 

XltJ 
liw 
Tit 



HYDROGEN 27 

Gaseous substances also react with h\ drogen occluded by metals, the 
increased activity bemg probably due to the existence of the hydrogen 
partly in, the atomic state and partly as hydride The combination of 
hydrogen with the halogens and oxygen is promoted by the catalytic J\ 
action of platinum and palladium, the same effect being noted by 
Kuhlmann 1 for the interaction of hydrogen and nitric oxide to form m 
ammonia The direct combination of nitrogen and hydrogen is not "i 
induced by these catalysts It is noteworthy that hydrogenation 
cannot be induced by either the spongy or colloidal form of platinum or 
palladium completely freed from oxygen, 2 and that hydrogen desorbed 
from these metals retains activity for some time 3 

A most important method for the application of hydrogen as a re- 
ducing agent has been discovered and elucidated by the researches of 
Sabatier and Senderens 4 A very succinct summary of their work and 
that of other investigators has been given by Sabatier 6 The method 
is simple, and consists in passing a mixture of the gaseous substance and 
hydrogen through a tube containing the finely divided metallic catalyst, 
obtained by previous reduction of the oxide in the same tube For each 
reaction there is a suitable temperature, sometimes that of the atmo- 
sphere, but more usually 150 to 200 C The neighbourhood of 180 C 
has been found well adapted for many reactions The metals employed 
have been platinum-black, nickel, cobalt, iron, and copper Of these 
catalysts nickel is the most active, 6 and shares with cobalt the power of 
inducing reactions not promoted by the other metals Copper is the least 
useful of the five, platinum and iron occupying an intermediate position 

The preparation of the catalyst can be exemplified by a description 
of the operations involved in the case of nickel Unglazed biscuit-ware, 
broken to the size of peas, and freed from iron by boiling for several 
days with dilute hydiochloric acid, is rendered more porous by heating 
to redness for half an hour After immersion in a concentiated solution 
of niekel nitrate, and ev iporation of the liquid, the material is dried at 
100 C , ind subsequently heated until evolution of oxides of nitrogen 
ceases 

2Ni(N0 8 ) 2 ==2NiO+4NO a +O a 

The icductiou to met il is effected in the hydiogcnation apparatus, the 
oxide being pi u eel in i h ud #1 iss tube 1 metre long, and with a boie of 
2 cm , suppe>ited in i si mting position, ind sinioundcd by in 11011 tube 
ii ivm<r holes dulled m it ie>i the insertion oi thcimomctcis The 
hydiogcn employed is wished successively with in iciel solution of 
potissnnn pe mi in<r m lie , e one e nil iteel sodium hydi oxide, ind eon 
eenti ited snlphmic aeiel, ind imilly pissed ovei licitcd, palladi/cd 
isbeste>s Dining the opei ilion the temperatnie ol the reduction tube 
is muni mud it 500 C, the end oi the leaetion being indicated by 
ccssatieui in the prodncliem ol watei 

1 Kuhlinum lundltn 1SV) 29 272 
WillstatUr uid Waldsdnmdt lut/ Hu J<)21 54 |B] 113 

s And<isoii 7'mws (Jhnn Aw 1<)22 121, IIOJ compuc ('hit/lock and Tyndall 
Phil Mntf 1 ( H)S |(>] 16, 2t Ushu 2'mns c'/wm A'OG 1<)10, 97, 400 Collie and 
Pattcison, /'/or C/UHI Aoc 1<)1J 29, 22 117, I md, J Ainu Ghcm 8oc 1919 41, 
545 Wdidl ilwl 1M20 42,950 

4 Sibititr uidScndcicna Com pi tuul 18<)7 124 1 JOS 1899,128 1173, 1900 130 
1701 131 40 1901 132 1254 133 321 1902 134 514 135 225 

6 babatiu, Bcr 1911 44 1984 

boo this senea, Vol IX Part 1 , 95 



W 



nage& fe w reason to think ifacwa tramb 

r*> * 

are much too large. 

Tbe foflowiug Table exhibits some of I 
more remarkable temperatures in the wh< 
range, according to the present state of < 



Extremity of Wedgwood's thenaotDcter....... ........ ft 

Pig iron, cobalt and nickel, meh from 150* to.,... Ij 

Greatest beat of a Smith's forge ..... * *,** .... 1 j 

Furnaces for glatjadeartbeQwajT, fro 4Oto ..... II 

Gold mclti . .. ........... .... 3 

Settling beat of flint glass ...... . . ., ~ ,. S 

Silrer melts .... ..., .. 2 

Copper melts ^ ... . . S 

Brass melts * . 5 

Diamond bums * * , I 
Red heat risible m da} -light 

Fahrenbi 
old >cii< 

Hydrogen and charcoal burn 800 to 100 

Antimony melts 8 a 

Zinc , , 70 

Lead dl 

Mercury boils 6fr 

Linseed oil boils ( X 

Sulphuric acid boils ^ 

Bismuth , ^ 7< 

Tm i4i 

Sulphur burns slowly , ^Q^ 

Nitric acid boils 2^. 

Water and essential oils boil 2 j ^ 

Bismuth 5 part*, tm 3 and lead 2, melt 710 



HYDROGEN 29 

activity of the evolved hydrogen depends on the pressure at which it is 
discharged at the cathode 

Zenghelis x proved the chemical activity of hydrogen to be much 
increased by bringing the gas in very minute bubbles into contact with 
solutions His process consisted in forcing the gas into paper cartridges 
under such conditions as to inhibit bubbling through the paper, but so as 
to facilitate reaction with the dissolved substance in the pores of the 
cartridge At 90 C an appreciable reduction of mercuric chloride to 
mercurous chloride was observed, and between 80 and 85 C a similar 
reduction of potassium chlorate to potassium chloride Contac I for thicc 
days at the ordinary temperature, and more rapidly at 65 C , yielded 
evidence of the conversion of carbon dioxide into formaldehyde and 
substances with characteristic sugar properties At ordinary tempera- 
ture, potassium nitrate was reduced to potassium nitrite , and under 
similar conditions of temperature an experiment lasting half an hour 
transformed sufficient nitrogen into ammonia to give the Nessler test 

The energy characteristic of the nascent state is attributed by 
Zenghehs to the very fine state of division of the reacting gas 

Reduction of Metallic Oxides Hydrogen can displace many metals 
from their oxides, the reduction taking place at the ordinary tempera- 
ture, as with silver and palladium oxides, or on heating, as with the 
oxides of copper, cadmium, lead, antimony, nickel, cobalt, and iron 
Sometimes these reductions are incomplete, an equilibrium being attained 
Such equilibria depend on the experimental conditions, an example being 
the action of steam on heated iron (p 15) 

Raschig a observed that a mixture of hydrogen and nitrogen peroxide 
passed through a heated tube reacts with such violence as to cause 
explosion 

The influence of the silent electric discharge on mixtures of hydrogen 
and other gases his been studied by Losamtch 3 Sulphur dioxide is 
rapidly reduced, with hbciation of sulphur 

SO 2 +2II 2 =2II 2 O+S 



Nitric oxide ic icts furly lajndly, foiming ammonium nitnte Two 
stages may be issunu el 

2NO | 21I 2 -2II/) | N 2 , Nj | 2lI/)=-NIT 4 N0 2 

At oiclm uy h mp< i lime puie liydio^e n slowly leduccs concenti itcd 
sulplmiK K id 1<> sulpluu dioxide indwilci 4 C aibon disulphide foims 
i blown insoluble solid o( the lonnul i US 2 ,II 2 Acetylene pioehices 
i h<rht yellow in iss conl lining two subsl uues one is i thuk liquid 
with UK loimuli(( II 2 2(JI t ) M is soluble in ctlu i uullus i pie is uit 
oeloui , I lu otlui is in insoluble se>lid (2( H 1I 2 ( 1 2 II 4 ), o I pungent odour 
inel \\ig\\ innluiilu weight 

Triatomic Hydrogen P ipeis on the ie tetivity ol hydrogen piepireel 
by the elutiolysis of dilute sulphmie leiel huvc been published by 
Osinn 5 "1 be speeiilie utivity ol the is \v is pioveel by Lowcnthil*' to 
be due to the picsmee oi sulphur dioxide elenveel lre>m the sulphuric acid 

1 /cnghilis (\>inpt nntl 1 ( )20 170 HSi 

Raschitf /jdl^rh tint/no C/itm 1 ( M)7 20 0<)4 3 J osimtch Bel 1007 40 4050 
4 Jones Man M(in(ln\lti Phil hoc 1 ( )17 61 No J 1 

B Osann, J pralt Chrnt 18 r >$, 58 J8f> 1814, 6 1, 500 , 1855 56 102 1850 69 1 
1857 71 355 185<) 78 OJ 1800 81 20 1804 92 210 
6 Lowenthal J pralt Chcm 1858 73 110 



4& ON ffSCIPZC MEAT* 

denoted fey 1 tod 0* oearly; because w 
haw to divide J by IS 6 f the specific gravity 
of mercury 

That bodies differ much in their specific 
heats, is manifest from tbe following facts 

1 If a measure of mercury of 212* be 
mixed with a measure of water of 32*, tbe 
mixture will be far below tbe mean tempera- 
ture. 

2 If a measure of mercury of 32* be mix- 
ed witb a measure of water of 212*, tbe 
mixture will be far above the mean 

3 If two equal and like vessels be filled, 
the one with hot water, the other with hot 
mercury, the latter will cool m about half 
the time of the former 

4 If a measure of sulphuric acid be mixed 
with a measure of water of the same tempe- 
rature, the mixture will assume a temperature 
about 240 higher 

These facts clearly shew that bodies have 
various affinities for heat, and that those bodies 
which have the strongest attraction or affinity 
for heat, possess the most of it in like circurn 
stances , in other words, they arc said to have 
the greatest capacity for heat, or the greatest 
specific heat It is found too that the same 
body changes its capacity for heat, or appa- 
rently assumes a new afUnity, with a change of 



HYDROGEN 31 

of methyl acetate by a Volumetric method Bredig and Fraenkel 1 
have based an accurate volumetric method of determining the con- 
centration of hydrogen ions on the catalytic decomposition of ethyl 
diazoacetate 

Tolman 2 found for the transport -number of the hydrogen ion the 
value 184 

A characteristic of the hydrogen ion is its tendency to form complex 
ions, yielding with ammonia the radical ammonium, NH 4 , 3 and with the 
amines substituted ammonium radicals The cation of the oxomum 
salts may be regarded as a complex ion formed by union of a neutral 
compound, such as ethyl ether, with the hydrogen ion Dimethyl- 
pyrone 4 also yields complex hydrogen ions, other examples being the 
amons of the primary salts HSO 4 ', HF 2 ', HCCV, HC 2 4 ', and others 5 

References to the work of other investigators of the hydrogen ion 
are appended 6 

THE STRUCTURE OF ATOMIC NUCLEI 

The problem of the constitution of atomic nuclei has been attacked 
from two opposite points of view One method has consisted in 
attempting to synthesize nuclei heavier than the parent , the other has 
been concerned with the disruption of atomic nuclei 

The synthetic process is exemplified by the work of Collie and his 
coadjutors 7 on the effect produced by exposing hydrogen at low pressure 
to the action of cathode rays Many experiments under different 
conditions were made In some of them the residual gas was found to 
contain varying proportions of helium and neon , in others the results 
were negative It has been suggested that the presence of these gases 
might be due to contamination from the material of the apparatus or 
from the atmosphere, but the elaborate experimental precautions 
adopted make such <m explanation unte nablc Earlier work by Ramsay 
and by Collie H had piovcd the piesence of both helium and neon m the 
rcsiclu il #<iscs ol old X i<iy bulbs 

Sir T T Ihomson tneei the (ffeel of e it hock rays in experiments 
similai to 1 hose oi ( olhe and Pitteison inel obt lined ue>t only helium 
and m on hut ilso a <onsid< rahlt piopoihon of i g is dei}ot< d by him as 
X a Ihomson })< IK \ < d t h< he hum uid neon to hav< been evolved from 
the nutmilsof i h< ippudus uud< i 1h< influence of the electric ehb 
ehu^e, ( olh< uid Pilhison i< Dueled lluse tfiscs is hiving 1 been 



1 HK di^ mid InidiM /nt^ili Il</h<H/i<ni I ( )() r > II f>2 r > /u/sr// pJit/ttHal Chan 
1007 60 202 * loliniii / \nni < Jnm hw l ( )ll 33 12! 

' Wdiid and Miol ih /<ih</i i>/i 1/^1 kit) ( In m IH ( M 12 Jf> 

1 \\ald< M /></ 1001 34 IIS > 

r AIM uid B dliindd / it <h nnunj (lion IHOS 2O 17 r > 

" Osl \\ald li/utnn/1 <lit <ill<f< nninni ( In inn I < ipsit 1S<){ 2,1 001 nnd <) r >J Zcil^cli 
?^;/s?/ al (fnw 1MOO ^5 5U Uilsinnn ihul 2<)l KU Host ibitl 1<)00 34 7e)2 
Wulf itn<l 1001 48 S7 Ostuald nnd 1 utlx i Hand uml HilJ* butlt {jcl od 1 upsic 
1010 4i7 Ndiisl hu ls)7 30 l r ) r )7 Injnvorth /;//* (lion *S f m JOOH 93 2187 
Kaly Puih and Mainde n ibt,I 1<)0<) 95 10<)(i (athcaii(7 Iml Enq Chtm 1022, 
14, 27S) haw dinmlxd a Himpl< h\dro^n ^ n< inior for UHC in making hydrogen ion 
dttirmnwtionH 

7 ( <>lli< and PHttuHnn /IO/M < ln>n *Sm lOli 103 410 Proc Chem Hoc 191S, 29 
217 (ollu rnn Itoij Sru 1011 |Aj 90 r > r )l C'ollio PatterHon and Masson 16*^,91, 
30 (oinpan MaHHon /*>or ( }nm *Sor li)li 29 2H 

8 Railway and (ollu \atnit 1012 89 502 Ramsay Trans Chem Soc , 1913 
103 2()4 g Ihomson Nature, 1913, 90, 645 



50 OH SPECIFIC SEAT* 

a view to obtain the trac mean temp*n* 



That water increases in its capacity for heat 
with the increase of temperature, I consider 
demonstrable from the following arguments: 
1st, A measure of water of any one tempera- 
ture being mixed with a measure at any other 
temperature, the mixture is less than two 
measures Now a condensation of volume 
is a certain mark of diminution of capacity 
and increase of temperature, whether the con* 
densation be the effect of chemical agency, a* 
in the mixture of sulphuric acid and water, 
or the effect of mechanical pressure, as with 
elastic fluids 2 When the same body sud- 
denly changes its capacity by a change of form, 
it is always from a few to a gieattr, as the 
temperature ascends , for instance, ice, water 
and vapour 3 Dr Crawford ack no \s kdgu 
from his own experience, that dilute sulphuric 
acid, and most other liquids he tried, \vcr 
found to increase in their capacity fur he it \\ ith 
the increase of temperature 

Admitting the force oi these arguim nts, it 
follows that when water of G'J* and iif arc 
mixed, and give a temperature denoted by 
119 of the common thermometer, we muut 
conclude that the true mean temperature u 
somewhere fc&w that degree I have already 



HYDROGEN 33 

step If this conception be correct, a marked tendency towards the 
formation of elements with even atomic numbers would be anticipated 
Harkins has pointed out that there is actually a great predominance of 
elements of this type 

Through his work on the mass spectra of the elements, Aston x is 
convinced that, with the exception of H 2 and H 3 , all masses measured 
by him are whole numbers The conclusion is subject to the limits of 
experimental error, but is equally true of atomic, molecular, elementary, 
and compound masses Aston has obtained evidence of the existence 
of isotopes, believed by Harkins to account for the divergence of atomic 
weights from whole numbers Indications of the separation of chlorine 
into two isotopes have also been described by Harkins 2 

In Rutherford's earlier experiments on the disruption of nitrogen 
and oxygen by the particles of radium-C, 8 he thought that both gases 
were capable of disintegration with expulsion of an atom of mass 3 His 
later investigations proved the method employed to fix the source of 
the radiation to be untrustworthy on account of the considerable 
variation in the thickness of films of metal foil The results obtained by 
a more direct and simple method indicated, at least for oxygen, that the 
particles originate in the radioactive source, and not in the volume of 
the surrounding gas In his view much experiment will be required to 
fix definitely the nature of the radiation, but the general evidence 
indicates it to consist of particles of mass 4 projected from the source, 
and to constitute a new mode of transformation of radium- C 4 

As a result of the insight respecting the inner constitution of atoms 
gained during the last twenty years, modern thought regards the atoms 
of all the different elements as having the same general type of structure 
The greater part of the mass of the atom is due to the presence at the 
centre of the atom of a positively charged nucleus of minute dimensions 
Around the nucleus is a region with a diameter of the order of 2 x 10~ 8 cm 
occupied by elections maintained in equilibrium by the forces from the 
nucleus According to the law of Moscley, the resultant nuclear charge 
of an atom is cquil to the atomic or ordinal number of that atom, 
varying fiom one " xtom " ol electricity for hydrogen to ninety two 
" itoms " loi \\\ in mm, 1 he 01 dm il numbers also representing the number 
of " plinct uy " c lee tions suiioundmg the atomic nucleus Except for 
mass, the or elm uy physical ind chemical properties of the atom depend 
entirely on the number ind n of the external electrons, 

that is, on the nude u c h u^e The imss oi the atom is a property of 
the nucleus, its e fftet on the oidmary pioperties of the atom and on the 
distribution ol the elections bung much less pronounced The pro- 
duction ol atoms with the s unc nuclear chirgc but of different nuclear 
misses, known is i\olupc\ 9 is explicable on this assumption 

The lemov il ol one or moic ol the external planetary electrons from 
the atom uncle r the influence ol electrical discharges or of light, or the 
elimination oi one ol the more strongly bound electrons by means of 
X-rays or /3-i lys, would elfect a transformation of the atom of a tern 
porary nature only, lor its restoration to its original condition would 

1 F VV Aston Phil M<U] , 1920 [<| 39 Oil 

2 Harkins Science 1020 51 289 Physical Review, 1920, 15, 74, Harkins and Hayes, 
J Amer Chem *Soc 1921 43 1803 

3 Rutherford Proc Roy Soc 1920 [A] 97, 374 
* Rutherford Trani Chcm tioc , 1922, 121,400 

VOL n 3 



5 OH SPECIFIC HIAT. 

Dr* Crawfotxl, when investigating the ac- 
curacy of the common thermometer, was a wam t 
that if equal portions of water of different 
temperatures were mixed together, and the 
thermometer always indicated the mean, thitj 
was not an infallible proof of its accuracy. 
He allows that if water have an increasing 
capacity, and the mercury expand incieasmgly 
with the temperature, an equation may be 
formed so as to deceive us This is in fact 
the case in some degree , and he appears to 
have been deceived by it Yet the increased 
capacity of water, is by no means sufficient to 
balance the increased expansion of the mercu- 
ry, as appears from the following experiments 

I took a vessel of tinned iron, the capacity 
of which was found to be equal to 2 at of 
water, into this were put 58 omxcs of water, 
making the sum = 60 ounces of uatcr I he 
whole was raised to anv proposed tempera- 
ture, and then two ounces of ict \vm put 
in- and melted, the temperature \\as then ob- 
served, as follows 



thermomttcr tvMce is fast isvtittr, thou r h it h*% but hilf 
incapacity ioi h( at, the turn s in \\huh t tiu immni if r i* 
in cooling in fluid^arc not, limiTon, tiirts of their s 
heats 






HYDROGEN 55 

* 

expressing the atomic weight of hvdrogcn by a fraction, and founded his 
table on the basis =100 The standard 0=1 was adopted by Memecke 
in 1817, by Bischof in 1819, and also by Thomson 

Dalton formulated water as HO, but Berzelms considered that its 
formula should be H 2 0, since it can be produced from two volumes of 
gaseous hydrogen and one volume of gaseous oxygen Convinced of the 
impossibility of determining atomic weights accurately, Gmelm and his 
adherents in 1826 and later years advocated the adoption of a set of 
equivalents, that of hydrogen being taken as unity, and that of oxygen 
as 8 on the basis of Dalton's formula for water According to Ber 
zehus's view, the atomic weight of hydrogen compared with oxygen as 
100 was 6 24, but in deference to the views of Gmelm he introduced the "1 
conception of double atoms, denoted by a horizontal line through the 
symbol of the element, the corresponding numbers being known as 
" Berzehus's atomic weights " In the table based on this compromise 
the ratio H was 12 48 100 in Berzehus's notation, or in round numbers 

I 8 in that of Gmelm 

Experiments by Dumas and by Erdmaftn and Marchand in 1842 
fixed the ratio H O as 12 5 100=1 8 00, and it remained unaltered 
until 1860 In 1858-1860 Cannizzaro proposed adopting for oxygen 
the atomic weight O=16, and, in accordance with his suggestion, the 
atomic weights of a number of the elements were taken as double their 
equivalents In 1860 Stas determined the atomic weight of hydrogen 
to be 1005 (O=8), m terms of Berzelms's system, and in 1865 he 
gave the value as 10025 compared with 0=16, in accordance with 
modern conceptions 

Although neither of these numbers agrees with the present accepted 
value, it is noteworthy that Stas was among the first to suggest em- 
ploying O=16 as the standard, a system adopted by him almost 
exclusively in. his published work He did not utilize the standard 
H=l, beyond stiting that in comparison with it the value for oxygen 
could not exceed 1596, <xnd giving a number of atomic weights cal- 
culated on this basis , but the itomic weight of hydrogen as unity proved 
very ittrictivt, ind w is always employed by many chemists, although 
some iclheuel to St is's t ible, e ileulatecl liom O=16 In his book on 
atomic weights, published m 1882, Clarke employed chiefly the values 

II = 1 ind O- 1500 is the b isis of c ilcul ition, although he also used 
O 16 is st ind iid In <i tu itisc on atomic weights, published m 1883, 
Loth u Me ye i uulSeiibtit uiopted the latio II O = l 15 90 but they 
also tued to inluxluce i system 1) iseel on the value O = l 

In 1 882 St is innoune e el i m vv v ilue ioi the atomic weight of hyelro- 
gen, 1 01 (O -=!(>) uiel in the following ye u M uigiiac * urged without 
success the idoption <>i St is's oiigmil value O 1C as the stanelaiel 
In 1885 Ostwild- (iitiei/eel St is's conclusion thit the v ilue O 10 
neeessit itcs Joi hydiogcn i v ilue highei thin unity, and employed the 
ratio II O 1 1(> is the b isis oi his itomic weights 

Sudi was the condition ol the sub]cet in 1887, when the publication 
of results obt lined by Cooke ind Richuds, and by Keiser, shed a new 
light on the mittci I heir woik, confirmed by that of Rayleigh and of 
Crafts, proved the ratio II 0=1 15 96 to be inaccurate, and indicated 

1 Mangnac, Arch Sci pliys nal , 1883 10 5-27 (Euvres Completes Geneva 1902, 
2,714 

2 Ostwald, Lehrbuch der allgemeinen Chemie, Leipsic, 1885, I, 44 



$4 0* mcmc HIAT- 



for water, is to mix equal weights $ 
water, and any proposed body of two knowi 
tcmpcratores, and to mark the temperature o 
the mixture Thus, if g pound of water o 
32% and a pound of mercury of 212% Ix 
mixed, and brought to a common tempera- 
ture, the water will be raised m degrees, and 
the merciity depressed n degrees ; and theii 
capacities or specific heats will be inversely 
as those numbers, or, n I m * * specific heat oi 
water : specific heat of mercury In thii 
way Black, Irvine, Crawford and Wilcke, 
approximated to the capacities of various bo- 
dies Such bodies as have an affinity for water, 
may be confined in a vessel of known capa- 
city, and plunged into water so as to be heated 
or cooled, as m the former cai>c 

The results already obtained by this method 
are liable to two objections 1st the authors 
presume the capacities of bodies while they 
retain their form are permanent , that is, the 
specific heat increases exactly in proportion to 
the temperature, and 2d, that the common mcr- 
cunal thermometer is a true test of tempt rature 
But it has been shewn that neither of these 
positions is warrantable 

The calorimeter of Lavoisier and Laplace 
was an ingenious contrivance for the purpose of 
investigating specific heat , it was calculated to 



HYDROGEN 37 

To correct the error caused by weighing in air, this value has been 
recalculated, 1 introducing a correction for vacuum, and the value 
H=6 2915 obtained The corresponding ratio is 

H 0=1 15894^10067 16, 

a close approximation to the value accepted at the present day 

In 1842, in co-operation with Stas, Dumas 2 repeated the work of 
Berzelius and Dulong, employing many precautions to ensure the 
purity of the materials Without applying any corrections, the value 
of the ratio found was 

H O=l 15958=10026 16 

Subtracting the weight of the water formed from the air dissolved in the 
dilute sulphuric acid employed to generate the hydrogen, 3 Dumas 
obtained the ratio 

H O=l 15988=100012 16 

The ratio of the two equivalents is 1 8, from which the ratio of the 
atomic weights in accordance with modern views is 

H O=l 16 

This value was for many years adopted as the atomic weight Dumas 's 
method has been subjected to searching criticism at various times 
Berzelius 4 objected to it on the ground that the air employed to displace 
the hydrogen at the end of the experiment dissolved in the water 
formed, thus augmenting the value for the atomic weight of hydrogen, 
and diminishing that for oxygen Melsens 5 pointed out that a similar 
error resulted from occlusion of hydrogen by the reduced copper, the 
weight of the oxygen being consequently too low The chief source of 
error in Dumas's method was the presence of occluded gases in the 
cupnc oxide employed, i point noted by Richards and Rogers 6 During 
reduction these gases were given up by the oxide, the consequent loss 
of weight being ie< kerne el as oxygen, whereas part of it was due to 
other occluded g is The usult, 15 9G to 1599 (H=l), indicates 
too low i value loi the itonne weight of hydrogen and too high for 
oxygen 

In 1842 JKiielmum uiel M IK hind 7 followed closely the lines maiked 
out by the e ulici work oJ JUi/elms anel Dulong, anel especially tint 
of Dum is lhe piee uitions i iken inel the souiees of eiroi ovcilexjkeel 
weie simil ir te) those chai utenstie ot Dumas's woik In some oi 
their experiments the (e>p])ei oxide was prcpucel from metallic copper, 
anel in others by he iting copper mti ite luemi erne set of lour cxpcri- 

1 Compare eiirlu A Rnalcuhtlion of tin Atomic Weights Jidcd (Smithsonian Mis 
odlancous ( 1 oll( < lions Washington I'MO 54, No J) 

<M)umis Ann < 1 /nni /V/ys ISM [ )| 8 18<) 

s Compart Scbt lun liutrat/( zu> (h whuhtt d(r Alowqcwiclitc Brunswick 1884,119 

* Berzelius Lchrbuch dcr Chctnic 5th ed Dresden 1843-1848, 3 1183, compaic 
Sebolicn Beitrage zur Qisckichte dcr Atomyewichtt Biunswack 1884 120 

6 Melsens compare Sebelicn ibid 119 

6 Richards and Rogers Amer Cfiem J 1893 15 567 

7 Erdmann and Marchand J prakt Chem , 1842 26, 461 



5g OH SPECIFIC MEAT, 

vessels of owqtwl bases. (See plate I, Kg, i), 
Supposing heat to be represented by a qoatftitf 
of liquid in each vessel, and temperature by 
the height of the liquid in the vessel* the 
base denoting the zero or total privation d 
beat y then the specific heats of bodies at any 
given temperature, r, will be denoted by 
multiplying the area of the several bases by 
the height or temperature, JT Those specific 
beats too will be directly as the bases, or as 
the increments of heat necessary to produce 
equal changes of temperature 

Let w and B^= the weights of two cold 
and hot bodies, c and C their capacities 
for heat at the same temperature (or the bases 
of the cylinders) , d = the difference of the 
temperature of the two bodies before mixture, 
reckoned in degrees , m = the elevation of the 
colder body, and n = the depression of the 
warmer after mixture, (supposing them to have 
no chemical action) , then we obtain the fol- 
lowing equations 



1 m + n = d 



r c d 

+~tt~C~ 



IV n 



HYDROGEN &) 

basis for ascertaining the atomic weight of hydrogen His mean 
result, recalculated with the atomic weights Ag=107 880, Cl=35 457 
Br=79 916, and N=14 010, gives the ratio 

H 0=1 15793=10131 16 

The value for hydrogen thus obtained was too high, in contrast with the 
low ratios previously published by Stas 

By oxidation of a known volume of hydrogen, van der Plaats l in 
1886 obtained a mean value corresponding with the ratio 

H O=l 1595=1003 16 

The investigation of Cooke and Richards, 2 begun in 1882, marks the 
opening of a new era in the history of the determination of the atomic 
weight of hydrogen, and after the application of necessary corrections 
the results yield a value identical with that obtained by Morley (p 41) 
in 1895 The hydrogen employed was prepared from zinc and hydro- 
chloric acid, by electrolysis of dilute hydrochloric acid with a zinc- 
amalgam anode, or by the action of aluminium on potassium hydroxide , 
and so purified by contact with potassium hydroxide, calcium chloride, 
sulphuric acid, and phosphorus pentoxide that spectroscopic tests failed 
to reveal the presence of any extraneous substance The hydiogen was 
weighed directly, and oxidized by copper oxide prepared from pure 
electrolytic copper, the water formed being absorbed by phosphorus 
pentoxide and weighed, all weighings being reduced to vacuum It was 
noted by Mendeleeff, 3 and later by Agamennone, 4 that the volume of an 
evacuated glass globe is diminished by atmospheric pressure, and at the 
suggestion of Lord Rayleigh 5 a correction for this diminution was 
introduced by Cookc and Richards 6 into their calculation, the hydrogen 
having been weighed in an elongated, cylindrical glass flask The 
ratio obtained was 

H 0=1 15869=100826 16 

An observation of Muuleleeff 7 that a change of pressure of one atmo 
sphere pioduccs a < m< -|Minliii_ r change m the volume of water, sug- 
gested to Brauuei 8 the neec ssity loi ipplymg a further correction to the 
ealeulition oi. Cooke uid Uiehirds, to eliminate an error introduced by 
then method o( determining the e ip icity oi their glass vessel The 
ratio as leealeulateel by linuner is 

H O-l 15879-100762 16 

The method employed by Keiser 9 in 1887 involved weighing hydro 

1 van doi Plaats Ann Phy^ Clum 1886, [0] 7 529 

2 Cooki md Huh u<ls I tor Atmr \td 1887 23 149 Amer Chem J 1888 10 81 

3 Monde Ice ft Tin *fosttHtyo/fls<s (Russian id) 1875 I ^ 85 and 80 p 218 

4 Agarmnnom and Bon< tti Atti R Aciad I tnca L88 r > [4] I 605 099 

5 Kaykigh Proc Itoi/ AW 1888 43 J r >0 

6 Cookc arid Richards, Pioc Amir Acad 1888 23, 182, Amcr Chem J 1888, 
10 191 

7 Mendel6eff The Weight of a Litre of Air (Russian ed.), 1894, I 57 

8 Brauner, Abegg and Auerbachs Handbuch der anorgamschen Chemie, Leipsic, 1908, 
2 i 20 

9 Keiser, Ber 1887, 20, 2323 



58 03? SPECIFIC HEAT 

beat or cold produced; then the quantity of 
heat m both bodies will be =* (c w + C W) jr 
(w + W) Mn. 

(w+W) Mn 



fcw + ClTj 



It is to be regretted that so little improve* 
meat has been made for the last fifteen years m 
this department of science Some of the earliest 
and most incorrect results are still obtruded 
upon the notice of students , though with the 
least reflection their errors are obvious I 
have made great number of experiments with 
a view to enlarge, but more especially, to 
correct the Tables of Specific Heat It may 
be proper to relate some of the particulars 
For liquids I used an egg shaped thm glass 
vessel, capable of holding eight ounces of 
water, to this was adapted a cork, with a 
small circular hole, sufficient to admit the stem 
of a delicate thermometer tube, which had 
two small marks with a file, the one at 92, 
and the other at 82, both being alxm the 
cork, when the cork wa& in the mck of 
the bottle, the bulb of the thermoiiu ter was 
in the cenire of the internal capacity \\ hen 
an experiment was made the bottle was filled 
with the proposed liquid, and heated a little 



HYDROGEN 4! 

the mean value for the atomic weight in the first series being 1 00850, 
and in the second 1 00848 

Leduc, 1 in 1892, also synthesized water by oxidizing hydrogen with 
cupnc oxide, the mean of two experiments giving the ratio 

H O=a 1588=10075 16 

The classical research of Morley, 2 a masterpiece of skill, ingenuity, 
and patience, carried out by a master of experimental method, consisted 
of four parts In the first he determined the weight of a normal litre 
of oxygen , in the second the value of the same constant for hydrogen , 
in the third the relative proportions by volume in which, under normal 
conditions, hydrogen and oxygen unite to form water, and in the 
fourth the amount Qf water formed by the union of weighed quantities 
of oxygen and hydrogen The methods of the first three parts are 
considered on pp 47 to 49, since they are of a physico-chemical 
nature , the fourth part involves a gravimetric process, and is accord- 
ingly described here 

In Morley's experiments the weight of oxygen contained in two 
globes was determined, and a quantity of hydrogen was weighed while 
absorbed in palladium The two gases were combined, and the weight 
of water produced was ascertained The gases were brought into 
contact at two platinum ]ets enclosed in a small glass apparatus (fig 2) 
previously exhausted and weighed After the combination, the residual 
gas in the combustion chamber and the connecting tubes was extracted 
by means of a Toepler pump, measured, and analysed The com- 
bustion chamber, the oxygen globes, and the palladium hydrogen tube 
were again weighed The difference between the original weights of 
oxygen and hydrogen and those of the gases analysed gave the quan- 
tities combined in the combustion chamber The gam in weight of the 
combustion chamber corresponded with the amount of water produced, 
and should have been equal to the sum of the weights of the gases con- 
sumed The observed difference was due to experimental errors, and 
indicated the degree of accuracy of the operation 

In most of the experiments the volume of hydrogen employed was 
between 42 and 43 litres, and the weight of water pioduced was about 
34 grams The proportion of uneombmed gas varied between one six 
hundredth and one ten thousandth of the tot il amount Each synthesis 
was complete in ibout one hour and a h ilf 

The giscs entered the eombustion clumber at the jets a, and com 
bmation was initiated by spiikmg leioss the gup between the \vnes jj 
The two tubes bb wcu idle el with phosphone tnhyeliidc kept in pi lee 
by asbestos, the oxide serving to prevent the eseipe of any traces of 
water formed The joints cc were ground to lit joints 

conncetmg the ipparatus thiough othci phosphone mhydneie tubes 
to the sourees ol oxygen and li\(liuL r <ii Ihc tubes bb weie sealeel at 
d and 6, notches indicating the points of subsequent li letuic The 
hooks it the ends ot the ipparatus facilitated the hydrostatic \\(jglnni: 
for determining its volume 

1 Leduc, Oompt rend, 1892 115 41 Ann Ghim Phys 1898 [7] 15, 48 

2 Morley Smithsonian Contributions to Knowledge, Washington 1895 29, No 980 An 
account of the gravimetric woik is given in Amer Ghem J , 1895 17 269 and a description 
of the density measurements in Zeitsch physikal Ghem , 1895, 17 87 Compare also 
Freund, The Study of Chemical Composition (Cambridge University Press, 1904) 



60 OH 8PBCIFIC HEAT 

not enter into consideration. But a* the heat 
of that was proved to be equal to I of an 
ounce of water, or to 4 of an ounce measure 
of oil, it is evident we must consider the 
beat disengaged in the 1st experiment, as from 

8 } ounces of water, and in the last as from 

9 | ounce measures of oil On this account 
the Cumbers below 29 will require a small 
reduction, before they can be allowed to re- 
present the times of cooling of equal bulks of 
the different liquids, in the last experiment 
the reduction will be one minute, and less in 
all the preceding ones* 

It may be proper to- observe, that the above 
results do not depend upon one trial of the 
several articles , most of the experiments were 
repeated several times, and the times of cool- 
ing were found not to differ more than half a 
minute, indeed, in general, there was no 
sensible differences If the air m the room was, 
many case, a little above or below 52% the due 
allowance was made 

I found the specific heat of mercury, b) 
mixture with water, and by the time of its cool- 
ing in a smaller vessel than the above, to be 
to that of water of equal bulk, as, 55 to l 
nearly 

I found the specific heats of the metals and 
other solids after the manner of Wilcke and 



HYDROGEN 43 

bination of weighed quantities of ammonia and hydrogen chloride when 
passed together into water until the solution was almost neutral, the 
slight excess of ammonia being determined by titration The result 
obtained does not accord with that of Morley 

Thomsen's second method 1 of m\ estimation embodied a novel 
principle Weighed quantities of aluminium were brought into contact 
with a solution of potassium hydroxide, and the evolved hydrogen 
dried and weighed, the results giving the value of the ratio H Al 
Another series of experiments was made, the evolved hydrogen being 
combined with oxygen, and the water formed weighed, the data 
obtained being employed to calculate the ratio O Al From the 
results of the two sets of experiments, the ratio of the atomic weights 
was calculated as 

H O=l 15869=100826 16 

In 1897 Thomsen 2 revised the results obtained in this research, 
introducing a correction for the reduction of volume accompanying the 
solution of the aluminium in the potassium-hydroxide solution The 
amended ratio is 

H O=l 158685=100829 16 

In 1898 Keiser 3 caused a known weight of hydrogen occluded in 
palladium to combine with oxygen, and determined the weight of the 
resulting water, the whole process being carried out m one apparatus 
The mean of four experiments gave the r^tio 

H 0=1 15880=100756 16, 

a close approximation to Morlcy's value (p 42) 

The principle of the investigation carried out by Noyes 4 in 1907 
was similar to that adopted by him in the research of 1889-1890 (p 40), 
hydrogen being oxidized by copper oxide, and the water formed being 
weighed in the oxidation apparatus Five series of experiments were 
made, but the results of the first were not employed in the final cal- 
culation, being vitiated by retention of water in the copper oxide 
The mode of procedure w is modifu d foi each series of experiments, the 
mean of twenty-five observations giving the ratio 

H O-l 158751-100787 16 

Lor convenience m comp uisou, the foiegomg icsults aie giouptd in 
the following table 

1 Ihomsdi Kdlvh anotfj Uhnn 18% II 14 

2 Ihomscn ibitl 1H<)7 15 447 

3 Kuscr inm ('htm I 1898 2O 7*J 

4 Noyts J Amn Chan Hoc , 1907 29 1718 1<J08 30 4 



[TABLE 



OK SPECIFIC HEAT. 



TABLE OF SPECIFIC HEATS. 



GASES 


q*al 


&. 


OLIDi- 


3 


VtuArmjtimn 

Hyarogca * * 




MM 

.001 


OrUd woodf, m& olw 


i 


Oxygen 


476* 


.006 


vtfvtabk tnbiaucM, 
from 4(10 - 


J 


Commoner 


M9" 


.oot 


Qucklim 

Pll-C0l (i 14} 




Carbonic acid 


S 


uxn 


Charcoal . 

Chalk 





Azotic - - 


79" 


*o, 


Hydnrt 1 m 
Fiiniglita (7) 


"3 


Aqueous vapour * 


'SS* 


.001 


U untie of todi 
Aalpbur 


*9 








Iron 


JO 


LIQUIDS 






Brtfi 











Copper - 


11 


Water ... 


I 00 


1 00 


Nickel 


10 


Arterial blood 


1 03* 




/me 


.10 


Milk (1026) 


98 


I 00 


Silver 




Carbonat. of ammon (i 035) 


96 


98 


Tin 


07 


Carbonat. of potash ( i 30) 


75 




Antimony 


.06 


Solut of ammonia ( 948) 


* 03 


$3 


C old 


0,5 


Common vinegar (i oa) - 


9* 


94 


Lrati 


4 


Venous blood 


89* 




itimi th 


04 
~ 


Solut of common salt (i 197) 


7* 


93 






Solut of tugar (117) 


77 




Oxu i of tlic mruli tut 




Nitnc acid (i so) . 


76 


M< 


>i \ l^ r tticttli tHcni^cl^Cfti 




Nitric acid (130) 
Nitric acid (i 36) 


68 
63 


H8 


4 cur *' ig to Cravtiorti 




Nitrate of lime (i 40) 




H 






Sulph acid and water, equal b 


^a 


H 






Muriatic acid (i 153) 


6) 








Acetic acid (1056) 


Ob 








Sulphuric acic* (i 844) 


j^ 


f 






Alcohol (85) 


7b 


(, 






Ditto ( 817) 


7 








Sulphuric ether (76) 


bb 


, 






Spermaceti Oil ( X)) 


S3 


. 






Mercury 


" 




^i 







HYDROGEN 45 

Three years later Fourcroy, Vauquelm, and Seguin * observed 
during a prolonged experiment that 12570 942 cubic inches of oxygen 
and 26017 968 cubic inches of h\drogen, reduced to 14 C and 28 inches 
of mercury, combined to form 7249 grams of water By direct weighing, 
a cubic inch of water was found to weigh 4925 grain, and of hydrogen 

040452 grain The combined weights of the two gases exceeded the 
weight of the water formed by 277 gram It follows from the results 
that 1 part by weight of hydrogen combines with 6 17 parts of oxygen, 
giving the ratio 

H O=l 1234 

In 1803 John Dalton fixed the atomic weight of hydrogen as unity, 
and gave the ratio of the atomic weights of hydrogen and oxygen 
acccording to the custom of the day as H 0=1 5 5, a value far wide 
of the mark In view of the statements of Gay-Lussac and Humboldt 
that water was formed by the combination of 2 volumes of hydrogen 
with 1 volume of oxygen, and those of Cavendish and Lavoisier that 
oxygen ^as fourteen times as heavy as hydrogen, Dalton in 1808 
substituted the ratio 

H 0=1 7 

The first calculation with any approach to accuracy was that of 
Wollaston 2 in 1814 From the combining volumes of hydrogen and 
oxygen as given by Gay-Lussac and Humboldt in 1805, coupled with 
Biot and Arago's determination of the densities of the two gases, 
Wollaston calculated the atomic weight of hydrogen to be 6 64 (0=100) 
Expressed in modern terms the ratio is 

H O=l 1509=106 16 

Although the hypothesis of Avogadro and Ampere as to the relation 
between the densities and molecular weights of gases was propounded 
m 1811, hall a centuiy elapsed before its acceptance by the chemical 
world Giy-Lussac's Lwv of Volumes, enunciated m 1808, 3 led 
Bcrzelms to the issumption tint the densities of elementary gases are 
propoitioiuil to then itoime weights Acting on tins assumption, he 
and Dulong \\\ 1821 dctei mined the densities of hydrogen and oxygen, 
the icsults h< mg ulcmd to ur T,S unity Lor i the density 

was ionnd to be 0088, and foi oxygc n 1 1026, the ratio being 

IE O = l 1595,38=09984 16 

This cxpc niTu nt gives is the itormc weight of hydiogcn 9084 (O 16), 
a result in good ueoid \vith tint obtuned by the same investigators 
by gravimeliu methods (p J(>) 

Subseenunt lesc mh pioved thU G ly Lussac's Law of Combining 
Volumes is not ex ut, but only an ippioximation, 4 so that oxygen and 
li\di< _ n elo not behivc is peiled giscs tor an accurate calculation 

01 the relitive vilues lor the itonuc weights of hydiogcn and oxygen, 
it is theietoie essential to know not only the relative densities of the 

1 l<ourcroy Vauquelm, and Scgmn inn clnm 1701 [1 1 vm 230 Scgum ibid , 
ix , 50 compare S( bclu n Beitra/e zur Gewhichte der Atomytivichte Brunswick 1884 115 

2 Wollaston Phil Tnun 1814 104,20 

3 Compare this stncs, Vol 1 , 14 

4 Compare ibid, 15 



64 <W SPECIFIC HEAT, 

solpbur, are remarkably low, and cany their 
character along with them into compounds, as 
ml, sulphuric acid, &c. 

Water appears to possess the greatest cap*, 
city for heat of any pure liquid yet known, 
whether it be compared with equal bulks or 
weights; indeed it may be doubted, whether 
any sohd or liquid whatever contains mom 
heat than an equal bulk of water of the same 
temperature The great capacity of water 
arises from the strong affinity, which both its 
elements, hydrogen, and oxygen, have for 
heat Hence it is that solutions of salts m 
water, contain generally less heat in a given 
volume than pure water for, salts increase 
the volume of water as well as the density, 
and having mostly a small capacity for heat, 
they enlarge the volume of the water more 
than proportional to the heat they contribute 

Pure ammonia seems to possess a high specific 
heat, judging from the aqueous solution, which 
contains only about 1O per cent If it could 
be exhibited pure in a liquid form, it would 
probably exceed water in this* particular 

The compounds of hydrogen and carbon, 
under the characters of oil, ether and alcohol, 
and the woods, all fall below the two last 
mentioned , the reason seems to be, because 
charcoal is an clement of a low specific heat 



HYDROGEN 47 

density of oxygen, the values obtained being 06948 and 1 10506 The m 

ratio of these densities is | 

D H Do=l 15 905;=! 0060 , 16 

In 1892 Rayleigh 1 employed hydrogen and oxygen prepared by ^ 
electrolysis As the mean of nineteen experiments with hydrogen and "^ 
eleven with oxygen, he found the ratio of the densities to be ^ 

DH D =l 15 882=1 00743 16 

In 1893 he determined the densities of the two gases relative to air, the 
ratio being 

D H D =l 158818=100744 16, 

a result almost identical with that found by him in the preceding year 
In 1895 Morley 2 published an account of his researches -The gravi- 
metric results of his investigations have already been considered on p 41 , 
the physico-chemical sections are briefly summarized here The weight 
of a litre of oxygen at C and 760 mm , reduced to sea-level in 
the latitude of 45, was determined by three senes of experiments in- 
volving nine, fifteen, and seventeen observations respectively, the mean 
value for each series being 

(1) 142879 0000051 grams 

(2) 1 42887 000048 grams 
(8) 142917 0000048 grams 

The mean value of the three series is 

1 42900 000034 grams 

The oxygen was prepared from potassium chlorate 

The weight oi a litre of hydrogen at C and 760 mm , reduced 
to sea level in the 1 ititudc of 45, was determined by five series of 
experiments, the number of obsuvitions being fifteen, nineteen, eight, 
six, and eleven icspcctively The v iluc obtained for each senes was 

(1)0 0809 38 000007 grim 
(2) 089970 000011 grim 
( J) 089880 0000019 gr im 

(4) " gi im 

(5) OS086G 00000034 gum 

The mem v due of ill the scues is 089897, but Moilcy considered the 
results of the iirst uul second senes to he too high, owing to the presence 
of merciuy v ipoui m the gl iss globe llns somcc of error was elimin- 
ated in the ot he i I hie c se ne s, the me in value c ilcul itecl fiom them being 

08987 > nil i gi un 

These results give (01 the me in utio of the densities of the two 
gases 

D n D =l 150002=100628 16 

1 Kaylcigh Proc Roy hoc 1892 50 448 1893 53 144 1900, 66 334 

2 Morley Smithsonian Contribution** to Knowledge Washington 1895 29, No 980, 
pp 1-94 and 110-114, Phil Mag , 1904, [6], 7, 667, compare Guye J Chim phys , 
1907, 5 215 



OH SPECIFIC MAT 



I used contained 33 per cent pure acidj 
this acid therefore, in combining with water, 
expels much heat* 

Quicklime is determined by Lavoisier and 
Crawford to be 22 ; I think they have under- 
rated it I find quicklime to impart as much 
or more heat than carbonate of hme, when 
inclosed in a vessel and plunged in water, o* 
when moed with oil Hydrat of hme (that 
is, quicklime 3 parts and water 1 part, or dry 
slaked lime) is fixed at 28 by Gadohn it 
was 25 by my first experiments t but I since 
find I have underrated it The subject will be 
adverted to in a future section 



SFCTION 



THEORY OF THE SPECIFIC 1 IF AT OF 
ELASTIC lit H)S 

Since the preceding section was printed off, 
I have spent some time in considering the' 
constitution of clastic fluids vnth regard to 
heat The results already obtained cannot be 
relied upon , yet lt 1S d ,ffic ult to conceive md 
execute experiments less exceptioi able than 
those of Crawford It extremely .inportant 



HYDROGEN 49 

of the ratio by another method l The weight of a normal litre of deton- 
atmg gas, prepared at C by electrolysis of an aqueous solution of 
sodium hydroxide formed by dissolving the metal in water, was deter- 
mined to be 535510 gram From this number, and the corresponding 
values for hydrogen and oxygen, the ratio of the combining volumes 
of hydrogen and oxygen was calculated, allowance being made for the 
slight excess of hydrogen always present after the explosion of detonating 
gas prepared at C At N T P the ratio found was 

V H V =2 00269 1 

Employing another method, Rayleigh a found the value 
V H V =20026 1 

In 1916 a very accurate determination of the ratio was made by 
Burt and Edgar 8 The hydrogen was prepared by the electrolysis of 
barium hydroxide, and the oxygen either by the same method or by 
heating potassium permanganate The measurements were made at 
N T P , and a slight excess of hydrogen was employed Five series 
of experiments gave the volume ratio 

V H V =2 00288 1 

(c) The Atomic Weight Ratio 

Of the foregoing data, the results of Morley and of Burt and Edgar 
are*the most trustworthy Combining Morley's ratio for the relative 
densities of the gases with that for their combining volumes, the atomic 
weight of hydrogen (O=16) is given by the expression 

A* 14. PU i 100628x200269 

Atomic weight of hydrogen = 

2 

=1 00763 

This result ippioxnn lies closely to that obtained by Morley in his 
gnvmutiK rest IK lies (p 42) 

If Morley's vilucs loi the weight of 1 litre of hydrogen (0 089873 
giam) iiid ol oxygen (1 42900 gi im) arc employed, Burt and Edgar's 
ratio gives ioi the itomie weight of luehogtn 

1 00772 

Adopting Gum inn's 4 moie piobible value foi oxygen, 142905, the 
atomic weight ol hydiogen becomes 

1 00769, 

which is piobibly I he most u cm ate lesult hithcito obtained 

Othei methods ol eileulition yield figures supporting those of 
Morley r lhey utih/e the elensities and other physical constants of 
hydrogen ind oxygen, and ue based on the purely physical methods 

1 Moilcy Smithsonian Contributions to Knowledge 1895 29, No 980 

2 Kayloigh Pioc Roy hoc 1904 [A], 73 153 

3 Burt and l<dgar Pkil Tranb 1916 [A] 2i6,393 

4 Germann J Chim phys 1914 12 66 

VOL II 4 



WE0KT or metric 

compared with equal weight* rf 
IMC acid and aqueous vapour* and of azotic 
gasorpi&gfzrfica^^air, as it wn then catted, 
Htxkr tbe idea of its being an opposite to oxy- 
gen or depkhgitticated air Indeed hit de* 
duction* fefpectitig azotic ga*, are not ooi>- 
wrth iiis cspcnments : for he makes a* 
12 and 13, which aye tbe 



only direct ones for tbe purpose, but be mfare 
tbe heat of azotic gae from the observed differ- 
ence between oxygen and common air Tbe 
result gives it less than half that of common 
air, whereas from the !3th experiment, scarcely 
any sensible difference was perceived between 
them He has in all probability much under* 
rated tf , but his errors in this respect what- 
ever they may be, do not aflfcct his system 

When we consider that aH elastic fluids are 
equally expanded by temperature, and that 
liquids and solids are not fo, it should seem 
that general law for the affection ot clastic 
fluids for heat, ought to be more easily deduct- 
ble and more simple than om for liquids or 
solids There are three 6upj>o ittons m regard 
to elastic fluids which ment discus^on 

1 Equal weights of elastic fluids may have 
the same quantity of heat under likeurcum- 
s lances of temperature and pressure 

The truth of this supposition u disproved 



HYDROGEN 



51 



results of modern gravimetric analysis If Noyes's value for hydrogen 
is adopted in the calculations, high values for chlorine are obtained x 

In the opinion of Noyes, the most trusts orth> value is the mean 
between his own and Morley's gravimetric result, II -=1 00774, and this 
view is strongly supported by the work of Burt and Edgar, and by 
calculations made by the method of limiting densities 

In 1898 the German Committee on Atomic Weights selected 1 01 as 
the atomic weight of hydrogen 2 In 1903 the International Committee 
on Atomic Weights altered 3 the number to 



a value still recognized at the present time In this series of text- 
books the value 

H=l 00762 

has been selected for the calculation of atomic weights 

1 Sources of error in atomic weight determinations are considered in several papers 
by Guye and his collaborators (J Chim phys , 1916, 14, 25, 195, 204, 1917, 15, 60, 208, 
360,405 1918 16, 46) 

2 Report of the German Committee on Atomic Weights, Ber , 1898, 31, 2761 , compare 
ibid , 1900, 33. 1847 

3 Report of the International Committee on Atomic Weights, Proc Chem Soc , 1903, 
19,2 



70 tUSaET OF SPECIFIC HEAT 

its formation must therefore be exactly equal 
to the whole heat previously contained in tilt 
charcoal on this supposition but the heat by 
the combustion of one pound of charcoal 
seems, at least, equal to the beat by the com* 
bastion of a quantity of hydrogen sufficient to 
produce one pound of water, and this last is 
equal to, or more than the heat retained by 
the water, because steam is nearly twice the 
density of the elastic mixture from which it u 
produced, it should therefore follow, that 
charcoal should be found of the same specific 
heat as water, whereas it is only about of it 
Were this supposition true, the specific heats of 
elastic fluids of equal weights would be in- 
versely as their specific gravities If that of 
steam or aqueous vapour were represented by 
1, oxygen would be 64, hydrogen 8 4, azote 
.72, and carbonic acid 46 But the supposi- 
tion is untenable 

3 The quantity of heat fa/uwjii/y to the 
ultimate particles of all elastu fiunl^ mint he 
the same unckr (lie same pn \surf and tcm- 
pe? ature 

It is evident the number of ultimate par- 
ticles or molecules m a given weigh t or volume 
of one gas is not the same as in another for, 
if equal measures of azotic and oxygenous 
gases were mixed, and could be instantly 



LITHIUM 53 

relatively high solubility of its chloride in alcohol or a mixture of alcohol 
and ether With tnphylhte fusion is unnecessary, the mineral being 
soluble in acids 

The method most generally applied to the isolation of lithium is 
based on the decomposition of the fused chloride by electrolysis, modifi- 
cations in practical details having been introduced by various experi- 
menters Bunsen and Matthiessen l passed the current from six Bunsen 
cells through the fused chloride contained in a porcelain crumble, 
with a carbon rod as anode and an iron wire as cathode Troosfc 
employed a similar method Guntz 2 mixed lithium chloride with 
potassium chloride, but his product contained 1-3 per cent of 
potassium His current was 10 amperes at 20 volts, with a cathode 
of iron wire 3-4 mm in diameter Borchers 3 added chlorides of 
other alkali-metals and alkaline-earth metals and a small proportion 
of ammonium chloride, and employed a current density of 10 amperes 
per 100 sq cm Tucker 4 electrolyzed the chloride without the addition 
of other material 

To avoid contamination of the lithium with alkali-metals, Ruff and 
Johannsen 5 employed a mixture of lithium bromide with 10-15 per 
cent of lithium chloride, which melts about 520 C The Muthmann 
copper electrolytic cell was used, with two iron wires of 4 mm diameter 
as anode and a current of 100 amperes at 10 volts 6 

Direct electrolytic preparation of lithium from aqueous solutions of 
its salts is not feasible, but can be effected when the salts are dissolved in 
organic solvents such as acetone and pyridme 7 A solution of lithium 
chloride m pyridme was electrolyzed by Kahlenberg 8 with a cathode 
of sheet platinum or iron wire and a current density of 2-0 3 ampere 
per 100 sq cm Patten and Mott 9 found that amyl alcohol is a suit 
able solvent, provided the current density is sufficiently high to ensure 
the velocity of deposition of the metal being greater than that of its 
solution in the alcohol 

Wmklcr's 10 suggestion to reduce the hydroxide with magnesium has 
been proved practie xble by Warren n The reaction is very energetic 

Physical Properties Lithium is a white metal with silvei-hke lustre 
It remains untarnished m diy iir, 12 but a freshly cut surface develops 
a yellow tinge if moistuu is picscnt In extremely thin layers it is 
translucent, the tr insmittul light having a dark, reddish-brown colour 13 
It is harder than c tsiuni, rubidium, sodium, or potassium, but softer 
than lead, the degree oi hardness on Ilydbcrg's 14 scale being 6 In 
ductility it resembles lead, aid can be drawn into wire 01 i oiled into thin 

1 Bunsen Annalut 1855 94 107 

Gunt/, Oornpt tuid 189i 117 7 *2 

3 Borchers Zeitsch J'lddroUitm 1894 I 361 1895 2 39 
* Tucker J Amir Chan tioc 1902 24 1024 
5 Ruff and Tohannscn Zeitsch J J liktrocli(m 1900 12 186 
Compare Gunt/ L Induitna Chwmca 1907 7 284 

7 von Laszcyynski Ber 1894 27 2285 Zeifoch khklrochem , 1895 2 55 von 
Las7czynski and von Gorski ibid 1898 4 290 

8 Kahlenberg J Physical Chew 1899 3 601 

9 Patten and Mott, ibid 1904 8, 153 

10 Wmkler, Ber , 1890 23 4b 

11 Warren Chem News, 1896 74, 6 

12 Dafert and Mikiauz, Monatsh 1910, 31, 981 

13 Dudley, Amer Chem J , 1892 14, 185 

14 Rydberg, Zeitsch physikal Chem , 1900, 33, 353 



72 TMOIY 0* WICIFJC RBAT. 

portion, or ai it aiajr now be called* 
taw!* is (fernoDstrated. 

Coiai 1* The specific heat! of equal wxgkt* 
of my two elastic fluids, am inversely as the 
weighte of their atoms or molecule*. 

2, Tte specific beats of equal 6#&* of elastic 
fends* are directly as their specific gravities, 
and inversely as the weights of their atoms. 

3, Those elastic fluids that ham their atonii 
the KO& coodcnsed, have the strongest attrac- 
tion for heat , the greater attraction is spent 
in accumulating more beat m a given space or 
volume, but does not increase the quantity 
around any single atom 

4 When two elastic atoms unite by chemi- 
cal affinity to form one elastic atom, one half 
of their heat ra disengaged When three 
unite, then two thirds of their heat is disen* 
gaged, &c And in genera!, when m elaiMc 
particks by chemical union become n , the 
heat given out is to the heat retained as m n 
is to n 

One objection to this proposition it may be 
proper to obviate it will be sud, an increase 
in the specific attraction of each atom must 
produce the same effect on the system as an 
increase of external pressure Now this lait 
15 known to express or give out a quantity of 
the absolute heat , therefore the former must 



LITHIUM 53 

water and m various organic solvents, such as methyl and ethyl alcohol, 1 
the lithium sal^s are highly dissociated The electric conductivity of 
their dilute Aqueous solutions has been investigated by Ostwald, 2 
Franke, 3 and Kohlrausch and Maltby 4 The electric conductivity of 
the lithium ion at 18 C is 83 4 References to other work on the 
properties of lithium salt-solutions are appended 5 

Transmutation of Copper into Lithium The transmutation of the 
baser metals into gold was one of the chief aims of the alchemists, 
Although their labours proved fruitless as regards their immediate 
object, they laid the foundation of that scientific chemistry to which 
the modern industrial world owes a deep debt of obligation In 1818 
Faraday contemplated as a possibility the transmutation of the metals, 
for he said in a lecture delivered before the City Philosophical Society 
" To decompose the metals, to re-form them, and to realize the once 
absurd notion of transmutation these are the problems now given to 
the chemist for solution " 6 

Interest in the subject was revived in 1907 by Ramsay's 7 announce- 
ment of the development of spectroscopic quantities of lithium in 
solutions of cupric sulphate or nitrate exposed to the radium emanation 
In control experiments made without the emanation no lithium was 
detected Mme Curie and Mile Gleditsch 8 repeated Ramsay's 
expenments, employing vessels of platinum instead of glass, but failed 
to detect the development of even a trace of lithium They attribute 
Ramsay's results to solution of lithium present in the glass of his 
apparatus Mile Gleditsch 9 detected the presence of lithium in a 
sample of pitchblende from Joachimsthal, as well as in other radioactive 
minerals, but failed to find any simple relationship between the pro- 
portion of lithium and copper present in the minerals examined The 
results 10 are summarized in the table 



Mineral 


Percentage of 
Coppei 


Percentage of 
Lithium 


Ratio of 
Copper to 
Lithium 


Joachimsth il pitchblende 
Color ido pitehblende 
Carnotite 


1 2 

15 
15 


00017 
00034, 
0030 


7059 
441 
5 


Chalcolite (Cornwall) 
Autumtc 


54 
Nil 


00011 
00083 


491 


Thorite 


Trace 


00033 





1 Compart Ilabc i unlhacl finish * lektrochun 1002 8 245 

2 Ostwald Zntwh p/ii/u/til Chun 1887 I 83 

3 Innkc ibid 189 r > 16 4<> $ 

4 Kohlrausch and M iltby Mzinu^ber K Akad Wiss Berlin, 1899 11 665 
Kohlrausch ibid 1<)00 n 1002 1<)01 11 102<> 1002, i 572 

5 JPolman J Anur (hem *Vo< 1911 33 121 Patten and Mott J Physical Chem , 
1904 8 153 Schlamp Zutt>ch phyitkal Cham, 1894 14 273, Bredig ibid , 1894 
13 202 

6 Compare Hydrogen p i2 

7 Ramsay Nature 1907 76 209 f 1 micron and Ramsay Trans Chem Soc 1907, 
91, 1593 Ramsay ibid 1909 95 624 

8 Curie and Gleditsch Compt rend 1908, 147 345 

9 Gleditsch, ibid 1907 145 1148 

10 Gleditsch, ibid , 1908 146 331 Le Radium, 1908, 5, 33, compare Ramsay and 
Cameron, Compt rend 1908, 146 456 



74 THEORY OF SPECIFIC HBAT 

order to compare them with that of water, 
we shall farther assume the specific heat of 
water to that of steam as 6 to 7, or as 1 to 
1 166 

Table of the specific heats of elastic Saids 



Hydrogen 9 382 

Azote 1 866 

Oxygen 1 333 

Atmos air.. . .1 759 
Nitrous gas .... 777 
Nitrous oxide . 54-9 
Carbonic acid . 491 
Ammon gas 1 555 
Carb hydrogen 1 333 



Olefiantgas .1 555 
Nitric acid . 491 
Carbonic oxide 777 
Sulph hydrogen 583 
Muriatic acid. 424 
Aqueous vapour 1 166 
Ether vapour 848 
Alcohol vapour 586 
Water .... 1 000 



Let us now sec how far thec results will 
accord with experience It is remark ible that 
the heat of common air comes out nearly the 
same as Crawford found it by experiment, 
also, hydrogen excels all tht rest as he deter- 
mined , but oxygen is muc n lower -ind i/otc 
higher The principles of Crawford's doc tru c 
of animal heat and combustion, however, ire 
not at all affected with the change He suits 
the reason already assigned for thinking tint 
azote has been rated too low, we sec from the 
Table, page 62, that ammonia, a compound 



LITHIUM. $i 

The results of their analyses of lithium chloride are 

AgCl LiCl=100 29 5780, whence Li=6 940 , 
Ag LiCl=100 39 2092, whence Li =6 939 

A description of the determination of the first of these ratios is given in 
Volume I of this series of text-books, as an example of the refinements 
employed in modern atomic- weight research 

Further evidence concerning the atomic weight of lithium was 
furnished by Richards and Willard in their synthesis of lithium per- 
chlorate by evaporating lithium chloride with perchloric acid The 
result obtained was 

LiCl 40=100 150 968, whence Li=6 936 

In the foregoing calculations the modern values for the atomic 
weights of silver and chlorine have been employed, but the following 
calculation indicates the assumption to be unnecessary Taking the 
composition of silver chloride to be that given by Richards and Wells/ 

Ag AgCl=100 132867, 
it follows that 



==0 295786 X 1 32867=0 393002 



The mean of this result and that found directly (0 392992) is 392997 
Hence 



" A = " = 150968X0 392997, 
Ag Ag ' 

=0 593300, 
=64 107871 

Accordingly, Ag=107 871, and Cl=107 871 X 32867=35 454 But 

LiCl=64 -1 50968=42 393 
Hence 

Li =42 393 35454, 

= 6939 

The curicnt table of the International Committee on Atomic 
Weights gives 

Li=694 

Molecular Weight R unsay 2 i i the lowcimg of the 

vapour pressure ol mereury produced by dissolving lithium in that metal, 
and from his results calculated lor the molecular weight oi lithium the 
value 7 1, approximately the same as its atomic weight A different 
result was obtained by Ileycock and Neville 3 by the cryoscopic method 
with sodium as solvent, their value being about lorn times the atomic 
weight, the discrepancy possibly arising fiom the susceptibility of 
lithium to oxidation 

Position of Lithium in the Periodic System In accordance with the 

1 Richards and Wells J Amer Ohem Soc 1905 27 459 

2 Ramsay, Trans Ohem Soc , 1889 55 521 

3 Heycock and Neville, ibid , 675 



on BEAT IT coMBtrrrio* 

the calorimeter of the above philosophc 
and to a notion that its results arc not alwi 
to be depended upon Much important 
formation *7> however, be obtained on t 1 
sn^ect by the use of a tety simple apparati 
as will appear from what follows : 

I took a bladder, the bulk of which, wh 

extended with air, was equal to 30000 gra 

of water; this was filled with any combusti 

gas, and a pipe and stop-cock adapted to 

a tinned vessel, capable of containing 30C 

grains of water was provided, and its capac 

for heat being found, so much water was ] 

into it as to make the vessel and water togetfr 

equal to 30000 grains of water The gas \ 

lighted, and the point of the small flame \ 

applied to the concavity of the bottom of 

tinned vessel, till the whole of the gas T 

consumed , the increase of the temperature 

the water was then carefully noted, whence 

effect of the combustion of a gwrn volu 

of gas, of the common pressure and tcmp< 

ture, m raising the temperature of an eq 

volume of water, was ascertained, exccp 

very small loss of heat by radiation, &c wh 

this method must be liable to, and which j 

bably does not exceed | or V^th of the who! 

The mean results of several trials of 

different gases are stated below , when 



* - J *tfr' 
LITHIUM 89 

the hydride The analogy between the physical constants and other 
physical properties of lithium hydride and those of the alkali-metal 
hahdes, and the liberation of htbmra at the cathode and hydrogen at the 
anode during electrolysis, indicate the hydride to be a, salt of hydrogen 
in its capacity as a weak acid l 

Lithium fluoride, LiF The fluoride is obtained in granular ft>n by 
concentrating a hydrofluoric-acid solution of the carbonate Whea 
crystallized from fused potassium chloride it forms regular octahedra, 
or leaflets with a mother-of-pearl lustre 2 Carnelley 3 gives the melting- 
point as about 800 C , and Poulenc 4 as about 1000 C , but Wartenberg 
and Schulz 5 found 842 C The boiling point is 1676 C , 6 and the 
vapour-pressure in atmospheres corresponds with the expression 

log p = 55100/4 57T+6 190 

The density of the fluoride is about 2 6 

At 18 C 100 parts of water dissolve 27 part of lithium fluoride 7 
The salt is almost insoluble in alcohol of 95 per cent strength de 
Forcrand's 8 value for the heat of solution is 1 04 Cal Its com- 
paratively slight solubility constitutes a link with the fluorides of the 
alkahne-earth-metals (p 54), and has been put forward as an argument 
in favour of the double formula Li 2 F 2 , derived from the double molecule 
H 2 F 2J since the salts of lithium with monobasic amons are usually 
readily soluble If this view be correct, the analogy to the alkakne- 
earth metallic fluorides is rendered even more striking It is supported 
by the existence of lithium hydrogen fluoride, LiF,HF, which crystal- 
lizes from a solution of the fluoride in hydrofluoric acid 

Petersen 9 has determined the heat of formation of lithium fluoride 
from the hydroxide in dilute aqueous solution 

HF,Aq +LiOH,Aq =LiF,Aq +16 4 Cal 

The heat of neutralization of strong acids and bases is usually about 
13 7 Cal , and the enhanced value for lithium fluoride may be attributed 
to the heat evolved during neutralization by the lomzation of the weak 
hydrofluorie aeid 

By combining the he it of neutraliz ition given by the foregoing 
equation with the he its ol formation of water, dissolved lithium 
hydroxide, and dissolved li\ili i Iluonde, an equation is obtained 
giving the heat oi ioimation of dissolved lithium fluoride from lithium, 
fluorine, and water 

LLiJ+(l<)+nII 2 O=Lil< (dissolved) +118 4 Cal 

The heat of formation of the solid fluoride is unknown, since its heat of 
solution has not been determined 

1 Mocrs Zcilwh anonj Chtm JU20 113 179 

2 Poulenc Ann Chim 7%s 1894 [7J 2 22 

3 Carnelley Landolt Born^tun and Roth 9 Tabdlen 4th ed Berlin 1912,220 

4 Poulcnc Ann Chim Phyi 18 ( )4 [7] 2 22 

5 von Wartenberg and Schulz Zeihch Elektrochem , 1921, 27 568, compare Albrecht 
and Wartenberg ibid 162 

von Wartenberg and Schulz loc cit 

7 Myhus and Funk, Ber 1897 30 1716 

8 deForcrand Gompt rend 1911, 152,27 

Petersen, Zeitsch physikal Chem , 1889, 4 384 



78 OK HEAT s? COMBUSTION 

was ignited, then weighed, and the combos* 
tioa was maintained by a gentle blast from a 
blow-pipe, directing the beat as much as pos- 
sible upon the bottom of the vessel , after the 
operation it was again weighed, and the loo* 
ascertained ; the result never amounted to 2* 
for ten grams, but generally approached it 
nearly, 

In order to exhibit the comparative effects 
more clearly, it may be proper to reduce the 
articles to a common weight, and to place 
along with them the quantity of oxygen known 
to combine with them The quantity of heat 
given out may well be expressed by the num^ 
ber of pounds of ice which it would melt, 
taking it for granted that the quantity neces- 
sary to melt ice, is equal to that which would 
raise water 1 50 of the new scale 1 he re- 
sults may be seen m the following table 

lib hydrogen takes 7lbi oxygen, prod 8 llm witrr mrit jajllx * 

carbur hydrogen, 4 5 w * car acd 85 - 

olefiant gas, 3 5 - 4 $ Ha 

carbonic oxide, 58 i $8 cirb and i^ 

oil, wax and ul 35 4J W & t4 rac 104 - 

oil of turp . _ ^ 

alcohol, _ g __ 

ether, 3 4 ^ 

posphorus i $ a > } ph > ami 60 

charcoal 28 j S il, icxl 4 , 

.. camohor . _ __ m 

r w A. car *c 70 

. caoutrhnuc 



LITHIUM 6* 

(fig &), the two breaks in the curve near 20 C and 100 C corresponding 
With the transition-temperatures of the individual h\drates The 
three portions of the curve correspond with the solid phases LiQ 3 2H/), 
JjiCl,H 2 O, and LiCl The break on the dotted portion of the curve at 
~1 C represents the transition point of the trihydrate, LiCM%O 
A saturated solution of the chloride m contact with the solid phase boils 
at 168 C 1 



drams Lnnium uniuriuv per ivi/ virurno w i*cof 

8 s i i 


















, _d_ 


^ 


-^-- 














/ 


^ - 


L\Jz> 














rVj 


oX 


/ 
















^ 


^ 
















V 


</ 




















/ 

































































20 40 60 80 100 120 

Temperature 
j< ia $ Solubility curve of lithium chloride 



740 160 



The solubility oi lithium chlondc has also been investigated by 
GciLich, 1 whose icsults die given m the table 



TompciatuK <' 
OramsJ i( I in 100 ^ ,<> 



10 <>() W 40 50 00 80 100 
72 78 r > 84 5 90 r > 97 103 115 127 5 



Reft i cnccs to woik on the physical piopcrtics of aqueous solutions 
of lithium chloiuh IK ippcudcd 2 

Solutions of lithium chlonde lesemblc witcr in their powci oi ab 
soibimr immomi (ompkx immom i compounds being foi mod Ihc 
anhydious lithium h ihdcb ilso absoib ammonia, Bonnefoi 4 having 

i (Jtilith /Jdlvh final Ohnn 1H(3 ( ) 8 281 

Munmnc Compt ruid 1S<)7 125 60 J lloskmg l ^\M^ \WW\ 1 400 
TomsaiulUctmui /^<h pineal Men 100 J 46 209 /ahn f^ 1901 3? 673 
1905 50 129 JJilt/, thr/ 1902 40 184 Arrhcmus 18 S7 I 29o , Wagmr 



Trans Chem Soc , 1901, 79, 493 

4 Bonnefoi, Ann Ohim Phys , 1901, [7] 23 317 



80 OH HEAT BT CO MB US TICK 

Mme must necessarily be rather too low, 
But Lavoisier is m this a* well as all the 
ether articles, hydrogen excepted, unwar- 
rantably too high* I think Crawford wilj 
be found too high , his experiments 00 the beat 
produced by the respiration of animals, sup* 
port flits supposition. 

WAX AND OIL Crawford's results are a 
little lower than mine, which they ought not to 
be, and are doubtless below the truth Lavoi- 
sier's certainly cannot be supported This great 
philosopher was well aware of the uncertainty 
of his results, and expresses himself accord- 
ingly He seems not to have had an adequate 
idea of the heat of hydrogen gas, which con- 
tributes so much to the quantity given out by 
its combustion , he compares, and expects to 
find an equation between the heat given out 
by burning wax, &c and the heat given out 
by the combustion of equal weights of hydro- 
gen and charcoal m their separate state , but 
this cannot be expected, as both hydrogen and 
charcoal in a state of combination must contain 
less heat than when separate, agreeably to the 
general law of the evolution of In at on com- 
bination In fact, both Crawford and Lavoi- 
sier have been, in some degree, led away by 
the notion, that oxvgenoub gab was the sole 
or nrinrmal <;nnrr< nf th* liahf mul h< it nrn- 



LITHIUM 63 

of lithium chloride from its elements is expressed by 
the equation 

[Li]+(Cl)=[LiCl]+97 9 Cal 

The heat of solution in ethyl alcohol is 11 74 Cal ,* in methyl alcohol 
10 9 Cal * The formation of compounds with alcohols has been investi- 
gated 3 (see p 62) At 25 C 100 grams of ethyl alcohol xfissolfS 
25 88 grams of the salt 4 

Lithium chloride forms double salts with the chlorides of other 
metals, such as copper, 5 manganese, 6 iron, 6 cobalt 6 nickel, 6 and 
uranium 7 With sodium chloride it forms a series of mixed crystals, 
but not with potassium chloride 8 

Lithium subchlonde, Li 2 Cl According to Guntz, 9 lithium chloride 
is converted by lithium into a hard, greyish substance of the formula 
Li 2 Cl It decomposes water readily 

2Li 2 Cl+2H 2 =2LiCl+2LiOH+H 2 

Lithium bromide, LiBr The anhydrous bromide is obtained by 
dissolving the carbonate in aqueous hydrobromic acid, and evaporating 
the solution to dryness in a current of gaseous hydrogen bromide 
Bogorodsky 10 has isolated three hydrates from the aqueous solution, 
each forming very deliquescent crystals At very low temperatures 
the tnhydrate, LiBr,3H 2 O, is deposited , at 4 C it is changed to the 
dihydrate, LiBr,2H 2 O , at 44 C this substance yields the mono- 
hydrate, LiBr,H 2 O , above 159 C the anhydrous salt is deposited 
A crystalline form is also described 11 containing 1-1|H 2 O For the 
melting-point of anhydrous lithium bromide Carnelley 12 gives 547 C , 
and Wartcnberg and Schul/ 13 give 549 C , but Ramsay and Eumor- 
fopoulos 14 found the much lower value 442 C At its melting-point it 
evolves bromine freely 15 The boiling-point is 1310 C , 16 and the vapour- 
pressure in atmospheres corresponds with the expression 

log p = 35600/4 57T+5 109 

The values obi lined by Krcmcrs l7 for the solubility in water are 
given m the table 



Temperature (* 
Grams IiBr in 100 j, ![/] 




> 11$ 


10 
161 


20 
177 


30 
190 


40 

202 


50 
214 


60 
224 


80 
245 


100 
266 



1 Pickering 7Vnws Clum hoc 1888 53 8(>5 

2 I tmoiiK Cmnpt roid 1807 125 00$ 

3 1 mm rand liissc It 7'mws Chcm tioc 1914 105 1777 

4 Turnci and Bissott ibid 191$ 103 J004 

5 ( 1 hass(vani Cowpt rnn1 18 ( )1 113 040 Cambi Oazzdta 1009 39 i , 301 
Chaascvant ( owpl raid, 1892, 115, 113 

Aloy Bull hoc (huti 1800 |3] 21 264, compaio I icbisch and Korrcng 
nf/rirr K Alad lUss litrlin 1014, 102 

8 Sdiatfu Jahtb Mm Jl<il Bd 1019 43 U2 

9 Gunt/ ( 1 utnpt nnd 1805 121 045 

10 "Bo^orodsl y / /i/m /%s Ctuni Soc 189$ 25 SIC 1804 26 209 

11 GuarcHchi Aid It A<ul /SVt Totino 101$ 48 7 $5 

1 ( 1 aincll(y fandrtlt lloni^w and Roth s Tabdltn 4th cd Bcilin 1912 220 

13 von Wartcnbug and Sclnil/ Zcituh JLltktrochew 1921, 27 508 compare Albrccht 
and von Wartcnberg ibid 162 

14 Ramsay and 1'umorfopoulos Phil Mag , 189() 41,360 

15 Guarcscbi loc cit 

16 von Wartenberg and Schulz loc cit 

17 Krcmers Pogg Annalen, 1858, 103,6?, 104, 133, 105 360 



S3 ON HEAT BY COMBUSTION 

tmiy, in proportion to its specific heat before 
the combustion A similar observation may 
be made upon the heat produced by the union 
of sulphur with the metals, and every other 
chemical onion in which heat is evolved. 

Before we conclude this section it may be 
proper to add, for the sake of those who ais 
more immediately interested in the economy of 
fuel, that the heat given out by the com- 
bustion of lib of charcoal, and perhaps also 
of pitcoal, is sufficient (if there were no loss) 
to raise 45 or 50 Ibs of water from the freeze- 
ing to the boiling temperature , or it is suffici- 
ent to convert 7 or 8 Ibs of water into steam 
If more than this weight of coal be used, theie 
is a proportionate quantity of heat lost, which 
ought, if possible, to be avoided 



SFCIION o 



NY1URAI ZntO 01 II \H>l K \iuu , 
Of ubwlittt Pin at ion of Hint 

If we suppose a body nt the ordin ir> tc mpt 
rature to contain a given quantity oi heat, like 
as a vessel contains a given quantity of water, 




LITHIUM 

The heat of formation in aqueous solution can be calculated fake that 
5 chlonde or bromide, and is given by the exptesssic^i 

[Li]+[I]+Aq =*LiI,Aq +80 1 Cal , 

and, since the heat of solution is 14 & Cal ,* the heat of formation of 
the anhydrous iodide from lithium and iodine is expressed by 

[Li]+[I]=[LiI]+652Cal 

Lithium iodide resembles the chloride and bromide in the formation 
of double compounds with alcohols 2 At 25 C , 250 8 grams of the salt 
dissolve in 100 grams of ethyl alcohol 3 With propyl alcohol it yields a 
complex of the formula 

LiI,4C 3 H 7 OH 4 

Like the other halides, lithium iodide forms double salts with other 
metallic iodides, such as those of mercury 5 and lead 6 

Lithium iodide tetrachlonde, 1 LiICl 4 ,4H 2 0, forms yellow, deliquescent 
needles, melting at 70 to 80 C, and is prepared by the action of 
chlorine and iodine on a saturated solution of lithium chlonde in hydro- 
chloric acid 

Lithium hypochlonte, LiOCl The hypochlonte is very unstable, 
and has not been isolated It is formed in solution by the action of 
chlorine on a solution of lithium hydroxide, 

2LiOH+Cl 2 =LiOCl+LiCl+H 2 0, 

but is rapidly decomposed with formation of chlorate 
3LiOCl==2LiCl+LiC10 3 

It is probably also present in the product formed by the action of 
chlorine on dry lithium hydroxide 8 

Lithium chlorate, LiClO 3 On evaporation of the solution obtained 
by mixing aqueous solutions of lithium sulphate and barium chlorate, or 
by neutralizing ehloiic <ieiel with lithium carbonate, lithium chlorate 
separates in needles According to Potiht/m, 9 the crystals thus 
obtained have the loimul i 2LiClO 3 ,II 2 O, but other investigators 10 
state tint they consist oi the in hydrous salt Above 270 C the 
chlorate decomposes into ehlonde, pel chlorate, and oxygen, in accord 
ance with the eqti it ions 

4Li(l<yj-LiCH-3LiC10 4 

Lithium chloiate is moic soluble in water than any othei moigamc 

1 liodisl o / Mm y/iys Chun MM 1888 20 r >()0 , 1889,21 7 

2 lurmi and BiHsitt THUI^ ('Jinn /Sw 1<)I4 105 1777 

3 luincr and Bissctt ibid 1<>1 J 103 1 ( )04 

4 lurnci and Biascit ibid 10(K> 

5 Dobrossordow / 7^/ss /%<? Chew &o< 1901 32 774 

6 JJogoiodsky ibid 189 J 25 W> 1894 26 209 

7 Wells and Whet lei Ztihth anonj Chem 1892 2 55 

8 Kraut Annalcn 1882 214 3 r >4 J unge and Naef Ber , 1883, 16, 840 

9 PotihUm J Russ Phys Chem tioc 1888, 20 541 

10 Mylms and Funk, Ber , 1897, 30 1716 Retgers Zeitsch pTiysikal Chem, 1890, 
5 449 

VOL II ^ 



84 OJi TSB ZIfcO OF TEM MRATUHE. 

we and water, supposing the capacities of 
these two bodies to be as 9 to 10, at the 
temperature of 82% it is known that ice oC 
32 requires as much heat as would raise water 
150, to convert it into water of 82% or to 
melt it Consequently, according to the 8th 
formula, p*g c 57 water of 32% must contain 
10 times as much heat, or 1500", That is, 
the zero must be placed at 150O* below the 
temperature of freezing water Unfortunately, 
however, the capacity of ice has not been 
determined with sufficient accuracy, partly 
because of its being a solid of a bad con- 
ducting power, but principally because the 
degrees of the common thermometer below 
free/ing, are very erroneous from the equal 
division of the scale 

Besides the one already mentioned, the, 
principal subjects that have been used in this 
investigation are, 1st, mixtures of sulphuric 
acid and water, ( Jd, mixtures of lime md 
water, 3d, mixture or toml>mitu>u of nitric 
acid and lime, and Hh, combustion ol h)dro 
gen, phosphorus and tharcoil I'pon these 
it will be necessary to cnlargv 

Mixture of Sulphuric And and Water 
According to the experiments of Lavoiner 




LITHIUM 



temperatures * For the density of an impure specimen, Brauner and 
Watte a found at 15 C the value 2 102 At a high temperature it 
Attacks platinum, 3 but its great stability is exemplified by its indifference 
towards hydrogen, carbon, and carbon monoxide 

Lithium monoxide is slowly attacked by water, with formation of 
the intensely alkaline solution of the hydroxide The heat evolved is 
given by the equation 4 

[Li 2 O]+Aq =2LiOH,Aq +B1 20 Cal 

Since the heat evolved by solution of 2 gram-atoms of hthium ia water 
is 106 4 Cal (p 62), and the heat of formation of water is 68 3 Cal , the 
heat of formation of the oxide from its elements is given by the equation 

2[Li]+(0)=[Li 2 0]+143 5 Cal 

Lithium peroxide, Li 2 O 2 Addition of alcohol to the aqueous solution 
obtained by the interaction of hydrogen peroxide and, hthium hydroxide 
precipitates the crystalline product Li 2 2 ,H 2 2 ,3H 2 O, a substance 
converted by drying over phosphoric anhydride into the anhydrous 
peroxide, Li 2 O 2 The method resembles that employed in the pre- 
paration of the peroxides of the alkaline-earth metals 5 The com- 
bustion of lithium in oxygen yields only a small proportion of peroxide, 
a distinction from sodium The peroxide boils 6 at 258 C 

The heat of formation of the peroxide from the monoxide and oxygen 
is given by the equation 6 

[Li 2 0]+(0)=[Li 2 2 ]+7 97 Cal , 

the corresponding equations for the peroxides of calcium, strontium, 
and barium being 

[CaO] + (0)=[Ca0 2 ]+4 11 Cal , 

] + (0)=[SrO 2 J+13 07 Cal , 

] + (O)==[Ba0 2 J + 18 36 Cal 



In this respect lithium displays close analogy to the alkaline earth- 
metals, occupying a position between calcium and stiontium Further 
analogy is shown by the heat of foimation of lithium peroxide from its 
elements, 6 

a )=[Li a OJ + 151 29 Cal , 



a value closely approximating to that of calcium peroxide, 

[CaJ | (0 2 H[CiO 2 J + 15043 Cal 



Divergence horn the othci alkali metals is made evident by the fact 
that sodium pel oxide has a considerably lowei heat of formation 7 

2LNa]+(0 2 )=[Na 2 2 ] + 117 69 Cal 
Lithium hydroxide, LiOH The hydroxide can be prepared from the 

1 ttickc and ]< ndcll tiprech&aal 1910 43 683 

Braunci and Watts Phil Mag 1881 [5] 1 1, 60 
1 Rickc and JindUl loc cit 

4 deiorcrand Compt rend , 1907 145 702 

5 de Forciand, ibid , 1900, 130, 1465 

6 deForcrand Ann Chim Phys 1908, [8] 15 433 

7 de Forcrand, Compt rend , 1900, 130, 1465 



8 OK THE Z110 Of TKMPEEATURE 

proportions, observes the increase of temper* 
ature, and then finds the capacities of the 
mixtures* Whence we have data to find tha 
zoo by formula 9, page 58. In giving hit 
numbers, I have changed his scale, the centi- 
grade, to Fahrenheit'*. 



Acid \Vker beat CTO!?. opt of mix. camp zero 

4 + 1 194* 442 <$<5* 

2+1 203 500 1710 

1+1 16! 005 1310 

1+2 108 749 2637 

1+5 51 876 31230 

1+10 28 025 1740 

The mean of these is 2300 , which is far 
beyond what Gadolm supposes to be the zero, 
as deduced from the relative capacities of 
ice and water, and to which he seeks to ac- 
commodate these experiments 

As the heat evolved upon the mixture of 
sulphuric acid and uater is so < onsidtr.iblc, 
and as all three articles are liquids, and con- 
sequently admit of hiving their capacity s as- 
certained with greater piecismn, I have long 
been occasionally pursuing the investigation 
of the zero from experiments on those liquids 
The strongest sulphuric acid of 1 853, 1 find 
has the specific heat 33, and 



LITHIUM 69 

Lithium polysulphides Fusion of hthium hydroxide with sulphur 
yields a yellow mass like "liver of sulphur," probably consisting of 
"^sulphides of hthium Berzehus isolated a hydrated disulphide, 
H 5 2 ,wH 2 0, by concentrating an aqueous solution of the monosulphidc 
"Lithium sulphite, Li 2 S0 3 Evaporation of the solution obtained by 
the action of sulphur dioxide on lithium carbonate suspended in water 
yields the monohydrate, Li 2 S0 3 ,H 2 , addition of alcohol or ether 
precipitates the dihydrate, Li 2 SO 3? 2H 2 O The sulphite is readily 
soluble in water, and is susceptible to atmospheric oxidation Heat 
expels the water of crystallization, and causes partial decomposition Into 
sulphate and sulphide Double sulphites of lithium with potassium 
and sodium have been prepared 1 

Lithium sulphate, Li 2 SO 4 The hydrated sulphate, LigSO^HgO, is 
obtained in monoclmic plates 2 by evaporating a solution of sulphuric 
acid neutralized with lithium carbonate Its density is 2 02 to 2 06 
The anhydrous salt is said to have been prepared by Retgers, s its 
melting-point being given by Huttner and Tammann 4 as 859 C , by 
Ramsay and Eumorfopoulos 5 as 853 C , and by Muller 6 as 843 C Its 
density is 2 21 

Lithium sulphate is readily soluble in water The heat of formation 
in dilute aqueous solution from lithium hydroxide and sulphuric acid is 
given by the equation 7 

2LiOH,Aq +H 2 S0 4 ,Aq =Li 2 S0 4 ,Aq +31 29 Cal 

Since the heat evolved by solution of 2 gram-atoms of lithium in water 
is 106 4 Cal (p 62), and the heat of formation of sulphuric acid from 
its elements 8 is 192 92 Cal , and its heat of solution in water 9 is 17 85 
Cal , the heat of formation of the sulphate in dilute solution from the 
elements is given by the expression 

2[Li] + [S]+2(O 2 )+Aq =Li 2 SO 45 Aq +348 46 Cal 

Taking 6 05 Cal as the heat of solution of anhydrous lithium sulphate 
the value given by Thomscn, 10 the equation for the heat of formation 
of the anhydrous sulph ite becomes 

2[Li| + [Sl + 4(0)=[Li 2 S0 4 ]+342 41 Cal 

For the heat of solution of the hydrate, Li 2 SO 4 ,II 2 O, Thomscn 10 gives 
the v iluc 3 1 1 C il , ind for its heat of hydration u the equation is 

fLi 2 S0 4 |+IT 2 0-Li 2 S0 4 ,II 2 0+2 64 Cal 
Rcfcunccs arc ippc ruled to investigations on double sulphates 

1 Hohng / in alt Ohttn 1S8S |2] 37 217 

2 liaubc Jahrb Mm 1S ( )2 u r >8 

J R(tg(is /jeil^ch pfn/^iliil ( 1 hun I HO I 8 H 

4 Huttner iml hiininnm /jtdvh anoiq Clum 100 r > 43 224 

r Kamsay ind iMiinoifopoulos Phil May 18% 41 iO() 

Muller TV Jahrb MintralJtnl Bd 1<)J4 30 1 ZttinJi Kry^t Mm , 1914 53 r >ll 

7 rhomacn, Th(rmncfitnut>try (I ongmans 1908) 115 

8 Thomson ibid 212 

9 Thomscn, ibid 47 

10 Thomson, ibid , 49 

11 Thomsen, tbid , 02 



g 03* THB ZERO OF TEMPERATURB, 

by weight* fora four parts of hydrat, a per* 
fectly dry powder, from which the water 
sanpot be expelled under a red heat If mor$ 
water is added, the mixture forms mortar, a 
pasty compefuiu}, from which the excess of 
water may be expelled by a boiling heat, and 
the hydrat remains a dry powder When 
hydrat of hme and water are mixed, no heat 
is evoked , hence the two form a mere mix- 
ture, and not a chemical compound The 
heat then which is evolved in slaking lime, 
arises from the chemical union of three parts 
of lime and one of water, or from the forma- 
tion of the hydrat, and any excess of water 
diminishes the sensible heat produced Before 
any use can be made of these facts for deter 
mining khe zero, it becomes necessary to de- 
termine the specific heat of dry hydrat of 
lime For this purpose a given u tight of 
lime is to be blaked with an excess of \\ater , 
the excess must then be expelled I)) he it till 
the hydrat is ^ heavier than the lime V given 
weight of this powder may then lx mixed 
with the same, or any other \\eight of \\atcr 
of another temperature, and itb specific heat 
determined accordingly By a variety of ex- 
periments made in this way, and with sundry 
variations, I find the specific heat of hydrat of 



LITHIUM 71 

into needles, probably the anhydrous salt l and isomorphous with the 
corresponding sulphate and selenate It yields a double salt with 
potassium, LiKCrO 4 At 18 C , 100 grams of water dissolve 110 9 
grams of the dihydrate 2 

A lithium dichromate has also been prepared 3 

Lithium permanganate, LiMnO 4 The tnhydrate, LtMhO^BHgO, 
forms dark- violet crystals, isomorphous with the perchlorate 4 The 
manganate has not been isolated 

Lithium molybdates 5 By varying the experimental conditions, 
Ephraim and Brand 6 have prepared six different molybdates by the inter- 
action of lithium carbonate and molybdic acid Li 2 0,Mo0 3 , 2Li 2 0,3MoO 3 , 
Li 2 O,2MoO 3 ,5H 2 , 3Li a O,7Mo0 35 28H 2 , Li 2 0,3MoO 3 ,7H 2 , and 
Li 2 O,4MoO 3 ,7H 2 They failed to obtain a salt with a higher propor- 
tion of Mo0 3 

Ephraim and Brand have also described a number of phospko 
molybdates of lithium 7 

Lithium nitride, Li 3 N The nitride is best prepared by the action 
of nitrogen on the metal at ordinary temperatures, 8 the product being a 
grey, amorphous, hygroscopic substance, unaffected by dry hydrogen or 
air, but rapidly decomposed by moisture It absorbs both nitrogen and 
oxygen from the air A ruby red, crystalline modification is formed by 
the action of lithium on nitrogen at 450 to 460 C It is less hygroscopic 
than the amorphous form, and does not absorb gases in the cold At 
840 to 845 C in a current of nitrogen the amorphous nitride becomes 
crystalline 

Water decomposes the nitride according to the equation 

Li 3 N+3H 2 =3LiOH+NH 3 

Guntz recommends the formation of the nitride as a convenient 
means of isolating irgon, 9 and its interaction with metallic chlorides as 
a method for jm p n m<r other nitrides 10 For the heat of formation he 
found 49 5 C il 1L It is formed by the action of light on lithium imide, 
Li 2 NII (p 72) 12 

2Li a NII ^ Li 3 N+LiNH 2 

Lithium hydrazoate, I iN 3 Neutiah/ition of hydrazoic acid with 
lithium hydioxide uul < onmitr ition of the solution yields colourless 
needle sol the monoliydi it< , LiN 3 ,II 2 O It is hygroscopic uid explosive, 
and is decomposed by he it IJ 

Lithamide, LiNII 2 The amide can be prepared by the action of 

1 Kitgfis /julvh i>ln/vlal ( In tn 1801 8 H 

2 Mylius uid iMinl hn I H07 30 17 H> 

J Itunmt Islx i n /Vw/'/ \n<tt<" ISM) 128 ill 
4 IM^is /n/sf// )>/n/^/<tI ( In ni 1801 8 H 

So< lsn this M< IKS Vol Vlf Put, TIT 
8 I< phi HIM in<l I i UK! /at (ft anonj (htnt 1000 64 258 

7 Fphraim and 1'iaml %l>ul JOH) 65 2U 

8 Daft it ind Mil 1 iu/ Momitsli 1010 31 081 pompaicTcnz Ber Deut pharm Get > 
1910 20 227 (iunl/ ( <ti}>t t(i\d J80 r > 121 940 

9 Gunt/ Cowpt tintl 18 ( ) r > 120 777 

10 Guntz, ibid 1002 135 7*S 

11 Guntz ibid 180(> 123 005 

12 Dafort and Mikl uiz Monatsh , 1912, 33 63 

18 Dennis and Benedict J Amer Chem Soc , 1898, 20 225 



00 ON THE 1** Of 



of fame, is 619. Bat supposing there 
no cbsgt5 of capacity upoo combination 
compound should only bare the capacity ,618 j 
whereas, m feet, the mixture produce* ao m- 
crease of temperature of about 180*, and 
therefore ought to be found wiri* a diminished 
cpaaty, or one below 618 Were this fad 
to be established, it would exhibit ao ineir 
phcable phenomenon, unless to those who 
adopt the notion of free caloric and combined 
caloric existing in the same body, or to speak 
more properly, of caloric combined so a* to 
retain all its characteristic properties, and c&> 
lone combined so as to lose tfee whole of them* 
Cue error m thtt statement has already been 
pointed out, in regard to the capacity of hma 
If we adopt the specific heat of Jiroc to be 
SO, and apply the theorem for the aero, we 
shall find it to be lo77O below the common 
temperature, as deduced from the above dat* 
10 corrected 

I took a specimen of nitric acid of the spe- 
cific gravity 1 2, and found, by repeated trials, 
its specific heat to be 76 by weight Into 
4600 grains of this acid of 35* temperature, 
in a thm flask, 657 grains of lime were gra- 
dually dropped, and the iruxture moderately 
agitated * m one or two mmutes after S-4ths of 
the hme was m and dissolved, the thermometer 



LITHIUM 7B 

Jteferences to other investigations of the properties of ddute solutions 
of the nitrate are appended l 

The heat of formation of hthmm nitrate in dilute solution is given 
by the equation 

[Li]+(N)+8(0)+Aq =LiN0 3 ,Aq +116 1 Cal 
Its heat of solution is only 8 Cal , a phenomenon probably due to the 

70 




-20 -/0 JO 20 30 40 SO 60 70 80 

Temperature 
FIG 4 Solubility curve of lithium nitrate 

formation of hydrates It follows that the heat of formation of the 
anhydrous salt from its elements is given by 

[Li] + (N)+3(0)-[LiN0 3 ]+115 8 Cal 

The heat of solution in alcohol is 4 66 Cal 2 

With ammonia m absence of water lithium nitrate forms a liquid 
chuMCtcii/cd by its lack of action on machine steel, iron wire, or 
mehromc wire iltcr contact for several months It has been suggested 
that the uldition ot a small percentage of water would render the 
liquid a good ibsoibcnt for the removal of ammonia from mixtures of 
the gas with nitrogen and with hydrogen 3 

The moleeulir electric conductivity of lithium nitrate between 
272 and 440 6 C is given by the formula 4 

^=41 140 238(/ 300) 

Lithium nitrate resembles the chloride in the non-formation of 
isomorphous mixed crystals with the corresponding sodium salt 5 

i Jonca and Gotman Z<*ch physikal Chem 1903 4* 26 ^ / ones 1Q a " d T ind a ft y ' 
Amet Ghem J 1902 28 329 Lincoln and Klein, J Physical C hem 1907 n 318 
Hartley Thomas and Applcbcy Trans Chem Soc 1908, 93 538 
Pickering Trans Chem tioc 1888 53 865 

Davis, Olmstoad and I undstrum, J Amer Chem Soc , 1921, 43 1575 

4 Jaeger and Kapma, Zeitsch anorg Chem 1920, 113 27 

6 Knckmeyer Zeitsch physikal Chem, 1896, 21, 85 



92 ON THE ZEEO OF TEMFBRAT0RS 

By adopting Crawford's capacities of hydro* 
gen and oxygen, and applying the theorem, 
page 58, We find the zero 1 290* from the 
common temperature But if we adopt the 
preceding theory of the specific heat of elastic 
fluids, and apply the 4th coral page 72, we 
must conclude that in thfe formation of steam, 
one half of the whole heat of both it$ ele* 
ments is given out , the conversion of Slbs of 
steam into water, will give out heat sufficient 
to melt 56lbs of ice , therefore one half of the 
whole heat in lib of hydrogen, and 7lbs of 
oxygen together, or which is the same thing, 
the whole heat m lib of hydrogen, or 7lbs of 
oxygen separately, will melt 344lbs of ice , 
now if from 688 we take 400, there remain 
288 for the Ibs of ice, which the heat m 
8lbs of water, at the ordinary temperature, is 
sufficient to melt, or the heat in lib ts capable 
of melting 36lbs of ice hence the /.ro will 
be 5400 below freezing water 

Combustion <>f Pho\plnn u\ 

One pound of phosphorus requires 1 Jib of 
oxygen, and melts b6lbs of lee I he specific 
heat of phosphorus is not known, b'lt from 
analogy one may suppose it to have as much 
heat as oil, v^ax, tallow, &c \\hichisnearly 

Half 3Q mnrli *>c wnt*r FV/-\rvt *K* I-^cf nr*irl^ 



LITHTUH 75 

Lithium meta-arsemte, LiAsO 2 At 25 C the ternary system 
lithium oxide arsenwus o&ide^ater indicates the existence of a raeta- 
arsenite soluble in water without decomposition 1 

Lithium arsenate, Li 3 As0 4 The semihydrate, 2Li 5 AsO 4> H 2 O > is 
obtained by the action of hthmm carbonate on arsenic acid * The 
anhydrous salt is prepared by recrystallmng this hydrate from ftased 
lithium chloride, 3 its density at 15 C being 3 07 With excess of arsenic 
acid the normal salt yields deliquescent pnsms of the dihydrogen ar^en&te, 
2LiH 2 AsO 4 ,3H 2 0, from which water regenerates the tnhthium salt 4 

Lithium antunomde, Li 3 Sb Since the direct combination of lithium 
and antimony is very violent, Lebeau 5 recommends preparing the anti- 
momde by the electrolysis of a fused mixture of lithium and potassium 
chloride with an iron cathode covered with antimony It is a dark-grey, 
crystalline substance of a very reactive nature Its density at 17 C is 
3 2 3 and its melting-point is 950 C The compound is also formed by 
the action of antimony on a solution of lithium in liquefied ammonia 6 

Lithium antimonate, LiSbO 3 ,3H 2 The antimonate is precipitated 
in crystalline form on addition of potassium antimonate to a lithium 
salt in solution 7 Like the sodium salt, it is only slightly soluble in 
water 

Lithium carbide, Li 2 C 2 The carbide was first prepared by Moissan 8 
by the reduction of lithium carbonate with charcoal in the electric 
furnace 

Li 2 C0 3 +4C=Li 2 C 2 +3CO 

Tucker and Moody 9 were unable to prepare the almost pure carbide 
described by Moissan, and attributed their failure to the very small 
temperature interval between the formation and the decomposition of 
the substance The carbide is also formed by the interaction of lithium 
and any of the allotropic modifications of carbon m vacuum at dull 
red heat , and by the combination of the metal with carbon monoxide 
or dioxide, or with cthylcnc or acetylene, an impure product is obtained 10 
Lithium caibidc is a white or grey crystalline substance, its density 
at 18 C being 1 05 At bright red heat it is decomposed, and Tucker 
and Moody lound that at 925 C and a pressure of fifty pounds to the 
sqin.ro nidi it ibsoibs niliofijcn ficdy with formation of cyanamide, 
dicy 111 miidi , ind ( y inidi It is a powerful icduccr, decomposing watci 
cnei^etu ill\ it oidiiiuy temperatures with formation of acetylene 

C 2 Li 2 +2lI 2 O -C 2 II 2 +2LiOH 

It ignites in fluoiiiu ind chlorine without the application of heat, and 
on ginlli winning in 1lu \ ipoui ol biommc, iodine, or phosphoms It 
combines with oxygen, sulplmi, and sdeinum at dull icdncss 

Gunt/ 1() i^ivcs tlu IK it evolved in its action, on water as 37 1 Cal , 

1 Sfliromomakus ind dt Bui lui ti(tv C/IDH 1 ( )20 39 42 J 
P imim Islx ig Poqq Awnalen, 18(>b 128 311 

3 dt SdmltMi Hull Mr <lnw 1889, [3] 1,479 

4 1 > itiinu lsb( i^ lo( cit \ 
r I(b(iu Hull Nor clntn 1002 [*], 27 2^4 ^ 

Jcbcau ibid 2 r >() r '< OA 

7 Hcilstcm and von Blao^o Melanges phy* etcTwn de Bull St Petersbourg 1889 13,1 

8 Moissan Compt urnl 189(> 122 302 

9 Tucker and Moody J Amer Chem Soc , 1911, 33, 1478 
10 Guntz Compt rend, 1896, 123 1273 1898 126 1866 



OK TUB ZfifcO OF TEMPfcRATTJftfe, 



_ ___ ^ 
IX 26 + 2 6 x 1 333 3 6 X 491"" 600(r 

where A represents the degrees of temperature 
which the combustion of lib of charcoal 
would raise the product, or 3 61bs of car- 
bonic aczd From this, A is found = 6630* 
But this heat would raise 3 6lbs. of water 
~ 6650 X 491 s 3265 Or it would raise 
lib of water, U750", or it would melt 78lbs 
of ice Lavoisier finds the effect = 961bs 
and Crawford finds it = 69 So that the 
supposed distance of the zero is not discoun- 
tenanced by the combustion of charcoal, as 
far as the theory is concerned 

Combustion of Oil, H a z and Tallo^ 

We do not know the exact cohstitution of 
these compounds, nor the quantity of oxygen 
which they require , but from the tvpcnmc nts 
of Lavoisier, as well ns from somt ittunpts 
of my own, I am inclined to think, tint they 
are formed of about "> parts of ilnrcoil ind I 
of h)drogcn by \\cight, uul that <> p irts re- 
quire 21 of oxygen for their couibustiun, tunn- 
ing 19 parts ot ctrbonic aucl and H ot water 
Let it be supposed that the /cm is <> { )0o be 
low freezing water, or tint the heat in water 
of 32% is sufficient to melt fOlbs of ice, then 



LlTmuM 7*7 

with charcoal yields the monoxide, sodium carbonate being reduced to 
the metal by similar treatment At the temperature of the electric 
furnace excess of charcoal produces the carbide (p 75), an example of 
the relationship between lithium and calcium 

The heat of formation of the normal carbonate and that of the 
primary carbonate have been calculated by Muller x 

2LiOH Aq +C0 2 ,Aq =;Li 2 C0 3 ,Aq +20 4 Cal , 
2LiOH,Aq +2C0 2J Aq =2LiHC0 3 ,Aq +22 1 Cal 

For the heat of formation of the solid normal carbonate de Forcrand 2 
gives the equations 

Li 2 0,Aq +(C0 2 )=[Li 2 C0 3 ]+54 23 Cal , 

2[Li]+(0)+(C0 2 )=[Li 2 C0 3 ]+44 20 Cal 

Basic carbonates have been described by Flucfeiger, 3 and a double 
salt with potassium by Le Chateher 4 

Lithium percarbonate, Li 2 C 2 6 Electrolysis of a solution of lithium 
carbonate at 30 to 40 C yields a solution of the percarbonate, 
which liberates iodine from potassium iodide instantaneously The 
crystalline salt has not been isolated 5 

Lithium cyanide has not been isolated, but Varet 6 has determined 
its heat of formation from the hydroxide and hydrocyanic acid 

LiOH,Aq +HCN,Aq =LiCN,Aq +2 925 Cal 

The low value is due to the heat absorbed during the lomzation of 
the weak acid 

Lithium thiocyanate, LiCNS The thiocyanate is obtained by 
neutralizing an aqueous solution of thiocyamc acid with lithium car- 
bonate, and evaporating 7 It forms very deliquescent plates, readily 
soluble in alcohol 

Lithium silicide, Li 6 Si 2 By heating excess of lithium with silicon, 
and expelling the uncombmcd metal at 400 to 500 C , the silicide is 
obtained as a very hygroscopic, dark-violet, crystalline substance 8 of 
density 1 12 It is a very reactive product and a powerful reducer 
With concentrated hydioehlone aeid it yields spontaneously inflammable 
sihcoethane, bi 2 II 6 , of which it may be considered a derivative 

Lithium silicates It usion of sand with lithium chloride yields the 
orthobihcatc, Li 4 Si0 4 , the mctawlicate, Li 2 SiO 3 , and an acid silicate, 
Li 2 O,5biO 2 9 When the chloride is replaced by the carbonate, the same 
substances are lormcd, 10 also mother acid silicate^ Li 2 O,2SiO 2 , and a 
subwhcate, Li 8 SiO fl u A study by Niggh 11 has proved the system 

1 Mullci Ann Chim Phyt> 1888, [OJ 15 517 

2 dc lorcraiid Com.pt rend 1908 146, 511 

3 Jbluckifcer Arch Pharm , 1887 [3] 25 509 

4 JcOhatdici Zcitwh phynkal Ohem 1890 21 557 
6 Ricacnfcld and Hunhold BLT , 1909, 42 4377 

6 Varct Gompt rend 1895 121 598 

7 Hermes J prakt Ohem 1866 97 465 

8 Moissan Gompt rend, 1902, 134, 1083 135 1284 
Hautefeuille and Margottet, ibid 1881, 93 680 

10 Rieke and Lndell, Sprechsaal, 1912 44 97 

11 Niggli, J Amer Chem Soc , 1913, 35 



95 ON THE ZERO OF TEMP1EAT0RE, 

the difference may well be attributed to th< 
loss unavoidable in my method of otttcm 
ban 

I might here enquire into the results of tin 
combustion of the other articles mentioned u 
the table, page 78, as far as they affect tb 
present question $ but I consider those abov 
noticed as the most to be depended upon 
From the result of defiant gas we may Jean: 
that a combustible body in the gaseous $tat 
does not give out much more heat than whc 
in a liquid state , for, oil and defiant gas ce; 
tainly do not differ much in their constitution 
one would therefore have expected the sam 
weight of olefiant gas to have yielded moi 
heat than oil, because of the heat required t 
maintain the elastic state , but it should seei 
that the heat requisite to convert a liquid t 
an elastic fluid, is but a small portion of th 
whole, a conclusion evidently countenance 
by the experiments and observations contamc 
m the preceding pages 

It may be proper now to draw up the r< 
suits of my experience, reported in the prcsci 
section, into one point of view 



LITHIUM* 70 

Lithium borates A borate of the formula LiBO^,8H 2 O crystallizes 
from mixed solutions of lithium hydroxide and bone aad At 47 C 
it melts in its water of crystallization, loses seven molecules of water 
at 110 C , and the eighth at 160 C The tenacity with which the final 
molecule of water is retained points to the possibility of the salt being an 
orthoborate, LiH 2 BO 3 ,TH 2 O l At 14 7 C its density is 1 897 

The anhydrous metaborate, LiBOg, is precipitated by the interaction 
of alcoholic solutions of a lithium salt and bone acid, 2 and can also be 
obtained by fusing lithium carbonate with bone acid s It forms 
tnclmic leaflets of pearl-like lustre, and melts 4 at 843 C Boiling with 
water converts it into the octahydrate 

Le Chateher's data for the solubility of the anhydrous metaborate 
in water are given in the following table 5 

Solubility of Lithium Metaborate 

Temperature, C 10 20 30 40 45 

Grams LiBO 2 in 100 grams of water 07 14 26 49 11 20 

For the heat of hydration Le Chateher found 

[LiBO 2 ]+8H 2 O=[LiBO a ,8H 2 0]+21 7 Cal , 
and for the heat absorbed by solution of the hydrate 

[LiB0 2 ,8H 2 O]+Aq =LiB0 2 ,Aq -14 2 Cal 

A polyborate, Li 2 B 8 O 13 , is obtained in crystalline form by heating 
lithium carbonate with excess of boric acid at 500 to 600 C for a long 
time 6 

DETECTION AND ESTIMATION OF LITHIUM 

The flame coloration and the spectrum (p 54) afford delicate tests 
for the presence of lithium From solutions which are not too dilute 
it can be precipitated as phosphate, fluoride, or carbonate Like 
sodium, it yields an antimonate of slight solubility, but m contra- 
distinction to potassium its platino chloride and hydrogen tartrate are 
soluble 

Ihe quintitativc estimation ol lithium can be effected by conversion 
into the sulphate or ehloiide When other alkali -metals are present, 
Tread well 7 recommends Gooch's 8 method, which involves conversion 
into chlondc, separation ol this salt by solution in amyl alcohol, and 
transform ition into lithium sulphate A modification of Gooch's 
method, devised by llamrnclsberg and modified by lieadwell, 9 in 
volves the extraction of the lithium chlonde with a mixture of equal 

1 HuHchlt ZitilsUi anory Chcm 1893,4 1() 9, oompaie liosonheim and Keglin ibid 
1921, 120, 10 J 

Ruschlc loc Lit 

* Jc (hatcher Compt rend 1897 124 1091 Bull Soc cJnm 1897, [3] 17 585 
4 van Klooatcr Z<it*>ch atwry O/tem 1910 69 122 

Jc CUatdicr Compt rend 1897 124 1091 
Lc Chateher Bull tioc ohun 1899 [3] 21 34 

7 Ircadwell Analytical Chemistry, 1st ed (Wiley, 1904) 2, 51 

8 Gooch Chem News 1887 55 18, 29, 40, 56 78 

9 Treadwell Analytical Chemistry, 1st ed (Wiley, 1904) 2, 52 



98 Off TEE $SKO OF TEMPERATURE. 

the ssine cause, namely, from a condensation 
of volume, and consequent diminution of 
capacity of the excited body > exactly in the 
same manner as the condensation of air pro- 
duces heat It is a well known fact, that iron 
3&4 other metals, by being hammered, be- 
come hot and condensed m volume at the 
same time , and if a diminution of capacity 
has not been observed it is because it is small, 
and has not been investigated with sufficient 
accuracy That a change of capacity actually 
takes place cannot be doubted, when it is 
considered, that a piece of iron once hammered 
in this way, is unfitted for a repetition of the 
effect, till it has been heated in a fire and 
cooled gradually Count Rumford has fur- 
nished us with some important facts on tho 
production of heat by friction He found that 
in boring a cannon for 30 minutes, the tempe- 
rature was raised 70*, and that it suffered a 
loss of 837 gnins by the dust, and scales torn 
off, which amounted to T } T part of the cylin- 
der On the supposition that all tin luat ua\ 
given out by //use stales, he finds they must 
have lost 66360 of temperature , when at the 
same time he found their specific heat not sen- 
sibly diminished But this is manifestly an 
incorrect view of the subject the heat excited 
does notarise from the scales merely, else how 



CHAPTER IV 

SODIUM 

Symbol, Na Atomic weight, 23 GO (O = 16) 

Occurrence Although sodium in the free state is not found in nature, 
it is present in combination in most minerals Soda-felspar or albrie is 
a double silicate of sodium and aluminium, 3Na 2 O,Al 2 3 ,6SiO 2 Sea- 
water contains 2 6 to 2 9 per cent of sodium chloride, NaCl, the deposits 
left by the evaporation of inland seas being known as rock-salt Both 
the carbonates and the sulphate of sodium occur dissolved in the water 
of many mineral springs, while the sulphate is a constituent of certain 
double salts, such as glaubente or sodium calcium sulphate, and blodtte 
or sodium magnesium sulphate Great deposits of Chile saltpetre or 
sodium nitrate, NaNO 3 , are present in Chile Cryolite or sodium 
aluminium fluoride, 3NaF,AlF 3 , is an important mineral found in 
Greenland Sodium carbonate occurs in South America and Egypt, and 
is also found as gaylussite, a double carbonate of sodium and calcium 
T^ncal or disodium tctraborate, Na 2 B 4 7 ,10H 2 O, is native to Thibet, 
India, and California, and a double borate of sodium and calcium 
called cryptomorphite is also found 

History The knowledge of sodium carbonate or " soda " is of 
great antiquity, as indicated by two references in the Bible 1 The word 
translated " nitre " in the Authorized Version means " natron " or 
" soda," and is correctly rendered " lye " in Jer n 22 in the Revised 
Version No alteration has been made in the other reference The 
confusion of terms evidently originated in the resemblance between the 
Greek virpw employed by foioscondes and the Latin mtium used by 
Pliny to denote sodium carbonate, and the word " mtie," loosely 
employed in early English as synonymous with " natron " or " soda," 
but now reserved for potassium nitrate 

In the sixteenth century Birmguccio seems to have appreciated the 
distinction between " mtrum " or soda and " sal nitn " or saltpetre 
Somewhat earlier the Arabs introduced into Europe the woids " natrun," 
" natrum," and " natron," signifying soda, and " mtrum," meaning 
saltpetre They also introduced the word " alkali " (p 1), but drew 
no distinction between soda, derived from the ashes of sea plants, and 
potash, obtained Irom the ishes of land plants These substances were 
denominated " fixed alkali " in contradistinction to the volatile 
ammonium carbonate 

In 1736 Duhamel dc Monccau noted the difference between the 
" mmeial alkali " or soda obtained from rock salt and the " vegetable 

1 Jeremiah n 22 Proverbs xxv 20 
VOL II 81 6 



100 OH THE MOTXOH 0? HEAT 

of the motion of heat in the same body, and 
MI its passage from one body to another, aris- 
ing from its incessant tendency to an equili- 
brium 

A solid bar being heated at one end* and 
exposed to the air, the heat is partly dissipated 
in the air, and partly conducted along the bar, 
exhibiting a gradation of temperature from 
the hot to the cold end* This power oi 
conducting heat vanes greatly, according to 
the nature of the subject in general, metals, 
and those bodies which are good conductors 
of electricity, are likewise good conductors oi 
heat , and mce versd 

When a fluid is heated at its surface, the 
heat gradually and slowly descends in the 
same manner as along a solid , and fluids seen: 
to have a difference in their conducting powci 
analogous to that of solids But when the 
heat is applied to the bottom ot a vessel 
containing a fluid, the case ib very different 
the heated particles of the fluid, in consc 
quence of their diminished sptuiic privity 
form au ascending current ind rise to tin sur 
face, communicating a portion of heat in then 
ascent to the eontiguous pirticUs, but stil 
retaining a superiority of temper ituu , so th i 
the increase of temperature m the mass is firs 
observed at the surface, and is constantly 



SODIUM S3 

lower part is surrounded by a seal of solid sodium hydroxide (H) The 
positive electrode ( + JB) encircles the upper part of the negative electrode, 
but is separated from it by a diaphragm consisting of a cylinder of wire- 
gauze (Z>) attached to the bottom of the chamber (C) Being specifically 
lighter than the electrolyte, the liberated sodium (S) rises to the surface 
It is directed by the diaphragm (D) n*to tne tubular iron chamber (C) 
placed over the negative electrode ( JE), and is collected Jyy means of 
ladles perforated to allow the molten hydroxide to dram off The gas 
liberated escapes at the opening (0) The periodic addition of fre^h 
sodium hydroxide enables the process to be carried on continuously 
A current of 1000-1200 amperes at 4-5 volts is employed, and serves to 
maintain the temperature after fusion is complete The yield of 
sodium is between 40 and 50 per cent of the theoretical amount 

In another electrolytic method formerly worked commercially, 
fused sodium chloride l was employed as electrolyte There are several 
practical difficulties to be overcome in carrying on this process, due 
partly to the corrosive nature of the chlorine liberated, and partly to the 
tendency to form the so-called subchloride of sodium Either the 
formation of this subchloride must be prevented, or, if produced, it 
must not be permitted to regenerate sodium chloride by interaction 
with the chlorine evolved at the anode The chlorine can be removed 
by contact at the anode with a heavy metal, such as lead, copper, or 
silver 2 Lowering the temperature of fusion by admixture with chloride 
of potassium or of an alkaline-earth metal, 3 or with sodium fluoride, 4 
prevents the formation of the subchloride 

Electrolytic processes are gradually displacing the older chemical 
methods of isolating sodium dependent on the reduction of the carbonate 
or hydroxide with charcoal or iron 6 On a small scale, magnesium can 
be employed as reducer 6 A laboratory method is the reduction of the 
peroxide with wood charcoal, coke, graphite, or calcium carbide 7 

3Na 2 2 +2C=2Na 2 C0 3 +2Na , 
7Na 2 2 +2CaC 2 =2CaO+4Na 2 C0 3 +6Na 

Hydrogen is a usual impurity m metallic sodium, and is e\olved 
when the metal reacts with mercury 8 It can be removed by prolonged 
heating in vicuum 9 

Physical Properties Sodium is a silver- white metil, lapidly tai 
lushed by atmospheric oxid ition, the pioccss being attended by a 
greenish phosphoicsccncc 1() In thin layers by tiansmitted light the 

1 lischcr Zeitwh Mektrochcm 1901 7 349 

2 Hopncr German Patent 1884 No 30414 Ashcioft ibid 1903 No 158374 
* Giabau ibid , 1890 No 502*0 

4 Konsoit fur clcktiochom Industi Numbcig ibid 1904 No 160540 compare 
Darling ibid 1902 No 8*097 J 1< nuilhn ln<>t 1902 153 65 

5 GJ ah am Otto / ihrbuUi d(r Chem , 3id ed , Bi uns\ucl 1885 I i 281, Schadler, 
Aniialw 18 *(> 20 2 IKvilk Ann Chun y%<? 185(> [3] 46 415 Donny xiul Mutsca 
Graham Gilo s Lihtbiuh d<r Chun Jrd cd Bmnswick 1885 I i 50 Wuicn than 
News 18<)I 64 2*9 Olu m J<abnl (Jiiealium Mcktion German Patent 190! No JiSiOS 
Dcvillc Ann Chun Plnj^ Lb r >5 [J| 43 6 Castnti German PaUnt 1S8(> No 40415 
Thomas British Patent 1884, No 0367 Ihomp&on ibid 1879 No 2101 

6 Wmkler, Ber 1890 23 46 7 Bamboiger Ber 1898 31 54 

8 Kahlonberg and Schlundt, J Physical Chem , 1905, 9, 257 

9 Salet, Ber, 1876, 9 354 

10 Linnemann, J prakt Chem , 1858, 75, 128 On the preparation and preservation 
of untarnished specimens, compare Bornemann, Zeitsch angew Chem , 1922 35, 227 



102 OH THE MOTION OF HSAT 

heat , and the heat, so propelled, is called ra* 
diant heat 

Till lately we have been used to consider 
the light and beat of the sun as the same 
But Dr Herschel has shewn, that there 
rays of heat proceeding from th sun, 
which are separable by a prism from the rays 
of light , they are subject to reflection, like 
light , and to refraction, but m a less degree, 
which is the cause of their separability from 
light The velocity of radiant heat is not 
known > but it may be presumed to be the 
same as that of light, till socrethmg appears 
to the contrary An ordinary fire, red hot 
charcoal, or indeed any heated body, radiates 
heat, which is capable of being reflected to a 
focus, like the light and heat of the sun > but 
it should seem to be not of sufficient energy 
to penetrate glass, or other transparent bodies 
so as to be refracted to an efficient focus 

Several new and important facts relative to 
the radiation of heat, have lately been ascer- 
tained by Professor Leslie, and published in 
his "Enquiry on Heat" Having invented 
an ingenious and delicate air thermometer, 
well adapted for the purpose, he was enabled 
to ma k the effects of radiation in a great 
Variety of cases and circumstances, with more 
precision than had previously been done Some 



SODIUM 85 

to the interaction of the vapour and the platinum, silver, iron, porcelain, 
or 1 glass of the containing vessel * 

The molecular weight was determined by Kraus 1 to be 20 by dis- 
solving the metal in liquid ammonia , other investigators 2 give values 
for the molecular formula varying between Na^ 5 and Na e 

The value of the specific heat at O 9 C is given by Griffiths * as 2829 
The specific heat from 185 to 20 C is 2845, according to Nordmeyer 
and Bernoulli 4 , from a4 to 7 C Rcgnault 5 gives 2943 , from 
79 5 to 17 C Schuz 6 ives 2830, and from to 157 C Bernini 7 
gives values varying between 2970 and 333 For th* specific heat 
of the solid at the melting-point, Rengade 8 gives 3266 According to 
Iitaka, 9 the specific heat % of the solid is 330, and of the liquid 347, the 
corresponding values for*the atomic heat being 7 59 and 7 98 

The latent heat of fusion per gram is, according to Joanms, 10 31 7 
cal , but Bernini n gives 17 75 cal , and Rengade 12 27 23 cal 

Sodium is a good conductor of heat, and as a conductor of electricity 
it stands next to silver, copper, and gold Its electric conductivity has 
been studied by several investigators 13 

The mean value u of the density is 978 Gay-Lussac and Thenard 15 
give the density at 15 C as 972 (water at 15 C =1) , Hackspill 16 
gives 9723 at C , Schroder 17 985 compared with water at 3 9 C , 
Braumhauer 18 9735 at 13 5 C and 9743 at 10 C compared with 
water at the same temperatures , Vicentim and Omodei 19 give 9519 
for the solid at the melting point and 9287 for the liquid , Ramsay 20 

7414 for the liquid at the boiling-point , Dewar 21 9724 at C and 

1 0066 at the temperature of liquid air (water at C =1) , and Richards 
and Brink 22 9712 at 20 C 

The value last mentioned for the density gives 23 70 as the atomic 

1 Kraus J Amer Chem Soc 1908 30 1197 

2 Ramsay, Trans Chem Soc , 1889 55 521 Meyer Zeitsch physikal Chem 1891, 
7, 477 Haber and Sack Zeitsch Elektrochem 1902 8 245 Haber Zeitsch physikal 
Chem 1902 41 399 Tammann ibid 1889 3 441 Heycock and Neville Trans Chem 
Soc 1889 55 b()6 1800 57 V76 1892 61 904 Phil Trans 1897 189 [A] 25 Abegg 
and feackur Winkelmann s llandbuch der Phynlc 2nd ed , Leipsic 1906 3 797 

3 Onfliths Proc Roy Soc 1014 [A] 89 561 

4 Noidnuytr and Bcmoulli Bcr dent physikal Ges 1907 5 175 compare Nord 
meyer ibid 1908 6 202 

r Rignault Pogtj Annalcn 1850 98 396 

6 Schu/ Wicd Annal<n 1802 46 177 

7 Btimm Phyulal Jdhrh 1 ( )0(> 7 168 

8 PM.H' Jtitll No< rtuw 1014 [4] 15 130 

9 In i N Rtp Idhokulmp Unw I01 f > 8 00 

10 Joanms Ann ( 1 hun Phy* 1887 [6] 12 381 

11 Btrnim Phy^ihd Zoituh 1000 7 168 

12 Ifongadi Bull hoc <Inw 1014 [4] 15 HO 

13 Mxtihicsscn Poqq Amicdcn 1857 loo 177 Jicimm Ciwento 1004 [5] 8 262 
Phyulal Anlvh 1004 5 241 Uunt/ and Biomcwsli Conijtt n nl 1008 147 1474 
Mullci Mitttllun/ie 1010 7 JO 755 Hacksjull Oomyl rend 1010 151 505 

14 I indolt Bornstdn ind M(ycihoffu Tabdlui 3rd ed Beihn 1005 226 

15 CHy I ussac and 1 IK mud Gtnclin Ktaut and Frudhiim s Handbudi do 
Chem 7th id Hudtlbcrg 1910 2 277 

] Hackspill Cotnpt rend 1911 152 259 Ann Chim Phy? 1913 [8] 28 61 -J 

17 Schrodti Pofjg Annalen 1850 106 226 107 113 

18 Braumhauer Ber 1873 6 655 

19 Vicentim and Omodei Wted Annalen, Beibl , 1888, 12 176 

20 Ramsay Ber 1880 13 2145 

21 Dewar Chem News 1902 85 289 

2 Richards and Brink J Amer Chem Soc , 1907, 29 117 



104 Otf TEE MOTIOK OF HEAT, 



& in any remarkable degree 9 wherea 
black paint, paper, glass, &c- are disposed I 
afaorb it, and consequently to radiate it aga 
in proper ciretnastances 

4 Screens of glass, paper, tmfoii, &c belt 
placed- between the radiating body and tl 
reiector, were proved to intercept the radia 
beat completely , but being heated themseb 
by the direct radiant heat, in time the th< 
mometer was affected by their radiation 
The beat radiating from hot water, does i 
then seem capable of being transmitted throu 
glass, like the solar heat 

5 Radiant heat suffers no sensible loss in 
passage through the air, a greater or 1 
radiant body produces the same effect, p 
vided it subtends the same angle at the 
Sector, agreeing with light in this respect 

6 The intensity of reflected heat diminis 
inversely as the distance, whereas, in \\% 
it is the same at all distances , the focus 
heat too differs from that of light , it ib nea 
the reflector, the heating effect dmimis 
rapidly in going outwards, but slowly m 
ing inwards towards the reflector I his sec 
to intimate the want of perfect tlastiuU 
radiant heat 

7 A hollow globe of tin, four inches 
diameter, being filled with hot water, coo 



SODIUM. 87 

at 18 C is 43 4, and at 25 C is 51 2 References to investigations 
of other properties of this ion are appended. 1 

Transmutation of Copper mto SodiumIn their account of their 
researches on the action of the ^a^R^^^ 311 ^^^ 0;a solja^ons of ( 
salts, Cameron and Ramsay 2 state tfeat Socfitoi isr 
of the action of the emanation oa, a^ts^^ceBE-^jfe^op^p 

Applications Sodium is eB^og^e^ &t ike joaa^ufa^tiare of 
peroxide, sodamide, and sodium cyaaasde, apd also UJL 
In the laboratory it finds application in the preparation of pure so<JniBtt 
hydroxide, and in presence of alcohols as a reducer*. 

Atomic Weight There is a very close association between tike 
atomic weight of sodium, and the atomic weights of potassium, stiver^ 
chlorine, bromine, and iodine, each element having been an important 
factor m the experimental investigation of both its own atomic weight and 
the atomic weights of the other five. The method of determining the 
ratio of the atomic weights o these elements to that of oxygen was 
originated by Berzehus, and was developed by Mangnac and Stas It 
involves three stages 

(1) The determination of the molecular weights of the chlorides, 
bromides, and iodides of sodium, potassium, and silver by analysis of 
the salts RXO 3 (R=metal, X=halogen), and induction from the 
ratios RX 30 

(2) The determination of the three ratios Ag NaX, of the three 
Ag KX, and of the three Ag AgX, values for the atomic weight of 
silver being obtained from these ratios in conjunction with the previously 
determined molecular weights of the metallic hakdes NaX, KX, 
and AgX 



_ 

3O X RX~"3O 

(3) The determination of the six ratios AgX RX, and the cal- 
culation of additional values for the atomic weight of silver from the 
expression 

RX AgX Ag Ag 

_ v o v _ o 

3O X RX x AgX"~80 

From the results obtained in (2) and (3) for the atomic weight of 
silver, a mean value is derived Employing this figure, the molecular 
weights of the silver halides arc calculated from the ratios Ag AgX, 
compared with those obt lined direetly in (1), and mean values derived 
Subtraction of the atomic weight of silver from these mean values 
gives the itomic we ights of the halogens Having thus ascertained the 
atomic weights oi silvci md the halogens, the moleculii weights of the 
alkali metal h ihdes arc calculated from the ratios Ag RX, and also 



1 WilsmoH /jdtuh i>h)^dal ('him 1900 35 291 Halxi and Sack 
Eldttodtuti 1<H)2 8 24<> Ostwild Jdtuh pli^iial ('him 18b8 2 i(> 270 Rudolph] 
ibid 18<) r > 17 iS r > vm 1 II off ibid 189 r ) 18 500 Storch ibid 1805 19 13 
Kohlruuseh ibid 1895 18 (><>2 liolofT Zdhch angcw Chun 1902 15 r >25 501 585 
Jahn Zeitvch pin/vlul ( 1 lnm 1900 35 1 Biltz ibid 1902 40 185 Abcgg and 
Bodlandci Zdtwh anouj Chetn 1899 20 496 Kahlenbcrg J Physical Chew 1901 
5 $75 Druckor Zeitsch Elektrocliem 1907 13 81 , compare A begg fheone cler electrolyt, 
Diswziatw-n Stuttgut 190 J 81 and Druckci Anotnahe der darken Elektrolyte, 
Stuttgart 1905 

Oameion and Kumsiy T terns Ohem Soc , 1907 91, 1593 

3 See p 55 



105 oyr TJTE MOTION or HEAT. 

fractional parti of its excess of temperature, 
by the three distinct sources of refrigeration in 
the air undermentioned : 

By abduction, that is, the proper conduct- 
ing power of air, the 584th* 

By recession, that is, the perpendicular our** 
rent of air excited by the heated body, th* 
k X 21715th 

By pulsation, or radiation, the 25S$d part 
from a ntetahc surface, and eight times ad 
much, or the S17th part from a surface of 
paper, (It should be observed, that Mr Les* 
lie contends that air is instrumental in the ra- 
diation of heat, which is contrary to the re- 
ceived opinion ) 

11 A body cools more slowly in rarefied 
air, than in air of the common density and 
the different species of air have thur respective 
refrigerating powers Common air and hydro- 
genous gas exhibit remarkable differences Ac- 
cording to Mr Leslie, if the cooling powtr 
of common air upon a \itrcous surfuc he de- 
noted by unity, that of hydrogenous gas will 
be denoted by 2/2837 , and upon a metallic 
surface the ratio is 5 to 1 7H f >7 In common 
air the loss from a vitreous surf KC is 57 bv ra- 
diation, and 43 by the other two c auses trom 
a metallic surface> 07 and 4T In hydroge- 
nous gas the loss from a vitreous surface is 57 



The earlier determu*atioE&s of the ratals ^tplv^ag the a&oinic weight 
of sodium commence wjtb the we&fe of J*e&ixy x :^3$9, jFour , 
of sodium chlorate gave ^^B^^t^Jfc i-^ "" &, . js* 

" >,^ i-* xttj 

^ -p ^ . 



NaCI0 3 



Several early senes of 
which the sliver necessary* 
weight of sodium cMosicS 
experiments are given in theiraeble * 




Experimenter 


JDate 


'* ^~ *>**<*- ; 


Peloose* 


1845 


54 141 00063 


Dumas 3 


1859 


54 1T2 00096 


Stas 4 


I860 


54 2078 00002 


Stas 6 


1876-1882 


54 2047 00045 



In Stas's second research allowance was made for the solubility of silver 
chloride in water, and for the presence of a trace of silica in the salt ' 
Clarke has calculated the weighted mean of these four series of experi- 
ments to be 

Ag NaCl=100 54 2071 000018 

The corresponding ratio for sodium bromide was also determined by 
Stas 6 to be 

Ag NaBr=100 954405 

Two series of determinations of the ratio 

AgCl NaCl=100 x 

should be mentioned The first was carried out by Berzclms 7 in 1811, 
and gave #=40 885 , the second was made incidentally by Ramsay and 
Miss Aston 8 in their work on the atomic weight of boron, and gave 
a? =40 867 Both these results are much too high 

The values obtained by Stas for the atomic weights of silver, chlorine, 
and bromine were 107 930, 35 457, and 79 952, and were employed for 
many years 9 By their aid the atomic weight of sodium can be cal- 
culated from the results already cited from Penny's experiments 
(NaCK), 3O) it follows that NaCl58500 From the mean ratio 
Ag NaCl it cm be calculated that NaCl=58 506 I he aveiage result 
is NaCl =-58 503 Irom the ratio Ag NaBi it follows that NaBr = 

1 Penny Phil Trant 18*0 129 25 
Ptlou/i Compt rend 1845 20 1047 

3 Durnas Ann Chim Phy<> 18 r >9 [11 55 18 ^ 

4 Stas OLiivrciComplete* Biussels, 1894, I 570 

5 Stas ibid 7(>8 778 

6 Stas ibid , 79G 

7 Berzehus Afhawllivgar i J<yf>iJc Kemi, etc Stockholm 1806-1810 5 117 
Gilbert s Annalen 1811 38 171 

8 Ramsay and Miss kmilv Aston Trans Chem Soc 1895 63 211 

9 A mathematical computation from all the early data leads to approximately the 
same values 



108 



ON THE MOTION OF HEAT* 



Correspondences of the Thcrmometnc Scales' 



old tcfc 


new scale old icale 


new to] 


212 


212* 


4O9*8 


342* 


22? 


222 


427 3 


352 


2386 


232 


445 3- 


362 


2526 


242 


463 6 


372 


2668 


252 


482 2 


S82 


281 2 


262 


501 


392 


2962 


272 


520 3 


402 


311 5 


282 


539 7 


412 


327 


292 


559 8 


422 


3427 


302 


580 1 


432 


3592 


312 


600 7 


442 


5758 


*?22 


621 6 


452 


3927 


332 


642 


762 



Erpetnncni I 

A meicunal thermometer having a bulb o 
half an in inch in diameter, and a scale o 
about 8 inches long from frc / ng to boihnj 
mercury, was heated to 4! > neu sok, nn< 
suffered to cool in a hon/ontil position in ai 
of 1-2 Ihc bulb in tin*, uul eurv other 11* 
stiumcnt piojectcd HAIM! mclus below th 
scale The times ot cooling \VLH tin s im 
fiom 14 1 to 21J, from '212 to 1 12 , ind iron 
H2 to ( ) 2 , namely, '2 minutes *md JO second 
each Ihib uis often repeated, the tune so 
cooling wer^ alwajs within 4 or ^ seconds o 
that above, and when any differences in tin 




11 experiments Cl NaX3*=100 1 164-858, whence Na=22 997 
8 experiments Bfc* NaRr^MO^ 12^*7*T > "\vjfejace V ^te'=s22 997* 

In the work of Richards $&& M^5JU^ **^ i - 
was exactly neutralized wills a j 
against pure silver Th^ fimq^MKr^ ^ ^ T, 



Hence, if Ag=107 880, 
105 99 > , so that 2Na+C~4W r 9&- A reww of ifte ato^e wfeig&fc <*f 
carbon 2 mdicdtcs that the value is probably between 12 OW a&d 12-005 1 
It follows that the atomic weight of sodium must he between Na =32 995 
and Na =22 998 

The mode/rn work of Bietea& a&d WeHs, Goldbaum, and Richards 
and Hoover indicates a Trfite between 22 9$5 and 22 998 for the atomic 
weight of sodium. In the accotmt of his work m 1915, Richards gave 
the preference to the lower number In this series of text-books, the 
value Na=*22996 has been adopted for the computation of other 
atomic weights The current table of the International Committee on 
Atomic Weights gives 

Na=2300 



COMPOUNDS OF SODIUM 3 

Sodium hydride, NaH By heating sodium contained in an iron 
vessel inside a sealed glass tube m an atmosphere of hydrogen, Moissan 4 
obtained sodium hydride m white crystals which condensed on the cooler 
part of the glass tube The temperature of reaction is about 360 C , 
and is a factor of importance, since for sodium hydride the interval 
between the temperature of formation and that of decomposition is 
small Much larger quantities of the hydride can be prepared 5 by 
passing a rapid current of hydrogen over the surface of sodium heated 
to such a temperature above 350 C as produces a yellow glow The 
hydride is carried off as a white smoke, and after electrical precipita 
tion is filtered through glass-wool The presence of metallic calcium 
facilitates its formation 

The density of the hydride is 92, 6 and the vapour tension for each 
interval of 10 between 300 C ind 410 C is 15, 17, 21, 27, 38, 55, 87, 
136, 201, 285, 396, and 540 mm respectively 7 Sodium hvdnde is the 
most stable of the alkali mctil hydrides, and CTsium hydride the least 
The sodium derivative is umflccttd by dry air, but decomposes in 
presence of tiaccs of moisture Although insoluble m organic solvents 
such as carbon disulphidc, oubon tctrichlonde, benzene, and turpen 
tine, it dissolves in the alkali metals ind their amalgams 

1 I it 1i uds ind Hoovd / im<t (him *Sor l<)L r ) 37 05 
This sc IKS Vol \ (>4 

3 l<oi wtlitUH <unal(/<nn s( ( tlnssuios Vol III Alloys \vith pot issium aie mentioned 
on p 1 r > ( ) 

4 Moissin Cotnjit void \ { )02 134 71 compnio Jlster and Utittl PliytiKal Zattch, 
1910 II 257 

5 Fphriim andMiohd lid) Chim Ada 1921 4 762 
Moissan Compt rend 1902 134 71 

7 Fphiaim and JVhdul Hdv Chim Ada, 1921, 4, 762, compare Keyes J Amcr 
Chem tioc , 1912, 34 779 



110 ON THE MOTJOH OF HEAT 

with tmfoil, pasted upon it, and the surface 
made as smooth as well could be , the ther* 
motneter was then heated, and the times of 
cooling were again noticed as before, re- 
peatedly The mean results follow j and t 
column of the differences of the logarithms of 
the degrees expressing the elevation of tem- 
perature above that of the surrounding air f 
which wa$ 4ff The temperature of the 
thermometer was raised to 275* per scale , that 
15, 235 above the air, and it is obviously moat 
convenient to reckon from the temperature of 
the air considered as zero in which case 19 
represents the difference of the logarithms of 
235 and 225, &c 



Bull ctrr Bulb ray Dif of 

Thcrmom* cooled &tco<!i *itfcuf4L Loftiitfe 

bttunti 

from 35> to aa^p ui u 17 19 

a*5 to 215 u 18 ^ 

15 to 20, ij is ,, 

~> r > o ^9? i i) n 

i<lj to 185 ij 2 ) a) 

1&5 to 1 ^ lO ai g^ 

J75 < l6 5 17 M "S 

U>j to lc 1 a^ . 



20 



,9 



U> 

to 



^ to 7 u j^J A4 54 

75 t * J j -45 Oi < a 

^3 to 54 />* ?j 75 

55 * f > 45 bi K8 f 7 

^5 to 3^ 7 g no 1*9 

,35 to Z 5 2o i< <j 146 

5 15 iOo 144 at 






the average amount present in tike water of the 
being about 2 7 per cent , while certain inland lakes contain a irmcfr 
higher percentage The Great Salt Lake in Utah has up to 30 per cent 
of the chloride in solution, and the Dead Sea 22 to 23 per cent 'Hie 
natural product known as " rock-salt " is the residue left on evaporation 
of inland seas, such deposits being found in Cheshire, at Stassfurt and 
Berchtesgaden in Germany, at Vic in France, and at Wiehczka in 
Gahcia Rock-salt is usuaUy associated with calcium sulphate, alumina, 
and sandstone At Stassfurt the layer of rock-salt is covered by another 
layer of readily soluble salts, technically known as " Abraum " salts , 
that is, salts which must be removed before the rock-salt is reached 

Rock-salt can be obtained from the salt-deposits either by mining 
or by making borings through which the salt can be extracted by water 
The colour of the mined product varies very much , it may be colourless, 
yellow, red, grey, or green Iron is a frequent impurity, and other 
foreign substances often present are magnesium salts, calcium sulphate, 
alumina, silica, and so on The presence of a small proportion of 
magnesium chloride renders the salt hygroscopic , it must be purified 
by crystallization 

When the salt is extracted from the deposits by the solution method, 
two concentric copper tubes are introduced through a boring, the outer 
tube serving to admit the water, and the inner as a conduit for pumping 
off the salt solution The dissolved salt is obtained by evaporation 

The salt found at Droitwich is in natural solution, and is not con 
tarmnated with iron The liquor is pumped to the surface and 
evaporated 

The concentration of the water of certain mineral springs and of the 
ocean also affoids a means of isolating salt Less soluble constituents, 
such as calemm sulphate, sepaiatc (nst Admixtuic of the salt with 
more soluble compounds, sueh is mi^iicsium ehlondt, is obviated by 
not cairymg the coneentiatum too fai Shipper 4 states that the 
elimination of potassium chloride can be effected by lepeated erystal 
h/ation of the salt Irom water 

lor laboratoiy use pure sodium chlondc is obtained by dissolving 
the commerenl product 111 witcr and i \ > < nn ih j by saturating the 
solution with liydiogcn chloiide The pine subst ince can also be 
prepared by the action of hydrochloiic icid on sodium carbonate or 
hydroxide 

Sodium chloiide ciyst illi/cs m ti inspire nt 01 opaque cubes, 

1 lUud J r/iywjuc !<>()* [4| 2 %<) 

2 rammann Mem Acad hi Pihuboiuy 1S87 |7] 35 No ( ) Koliliauach and von 
Stemwchr tiitzun(j<>bcr K Al ad Wtss Ihtlui 1<)()2 r >81 Wildtn Ztit&ch phy^ikal Chem 
18SS 2 49 Arrhemus ibid 1892 9 339 

J Guntz Compt rend 1883 97 1558 4 Slnppci Chun ^ews 1917 116 213 



112 ON THE MOTION OF HEAT 

of the highest intervals of temperature, the 
fciaes of cooling were rather smaller, and for 
the two last rather larger than required by 
the law, 

Experiment 3. 

As Mr. Leslie found the times of cooling 
of metallic surfaces considerably enlarged, m 
moderate elevations of temperature more es- 
pecially, I took another thermometer having 
a smaller bulb, and a scale of an inch for 10 
degrees, this was treated as m the last expert 
ment, and the results were asunder 



Thermom. cooled Bulb clctr Hulh coair 1 Lup ratiot 
second with tinfoil reduced 
iccond* 
Prom ^5 to <55 P in 38 4<> 46 


t>5 


to 


5^ 


40 5 > 5 1- 


55 


to 


4 r > 


^l- C>i- h ) 


45 


to 


35 


(> > 7 <l si 


55 


to 


25 


' 10} ]0) 


2> 


to 


J5 


1 JO 1 >S lf> J > 


15 


to 


5 


no no j > 



87 i 



Here the whole times of cooling, and the 
several parts are almost accurately is 10 for 
the vitreous, and as 1 ( 2 for the metallic surf ict 
They very nearly accord too with the loganth- 
mic ratios Ihe effect of the metallic sur- 
face differs less from that of the \itrcousm 






17* .; ^^3fe* 2m at 

the dteaasfty of the 
ipga& its melting-point ausd 1000 C 

mean value of several investigations 9 of the index of refraction 
of rock-salt at 18 C for the D-lme is 1 54432 For the electee eom- 
ductivity of fused sodium chloride at 960 C Braun* gives 0-9206 
reciprocal ohms, and at 750 C Pomcare 11 found 3 389 reciprocal -ohms 
For the specific heat of the fused chloride between 13 and 46 C 
Kopp 12 gives 0213, and from 15 to 98 C Regnault 13 gives 02140 
For rock-salt at C Weber 14 gives 02146, and from 13 to 45 C 
Kopp 15 gives 219 

As indicated in the table, the solubility of sodium chloride in water 
is only slightly augmented by rise of temperature 

'SOLUBILITY OF SODIUM CHLORIDE 



Observer 


Tern 

perature 

on 


Grams 
Nad in 
100 grams 


Observer 


Tern 
perature 

op 


Grams 
NaCl m 
100 grams 




\j 


Water 




\*> 


Water 


Andreae 16 





3563 


Earl of Berke- 


90 


3852 


99 


10 


3569 


ley 17 






99 


20 


3582 


99 99 


100 


3912 


99 


30 


3603 


Tilden and 


118 


398 


99 


40 


3632 


Shenstone 18 






99 


50 


3667 


99 99 


140 


42 1 


99 


60 


3706 


99 99 


160 


43 6 


99 


70 


3751 


99 99 


180 


449 





80 


380 









1 Kiukmiyu /dlvch phtj^ilal Chem 1890 21 53 liGhattlici Compt tend 1894, 
118 J50 liuil ind PI it<> Bit 190J 36 2357 Pufi Ivuutlja PohjUch lnt>t bt Petci* 
bin/ tOOO 5 Chun Ztntt 1000 i 1728 Ost \\ild J ptalt Chcm 1882 [2] 25 8 
In kt toft /nlvh unox/ Chun 1004 40 855 

*S<hufti lahib Mm Bed lid 1010 43 1 J2 

J Kuiniloft ind Sclu intBchushny I^uiotjal olyiith In^t &t Pctet^buxj 1905 4 227 
Chcm Amir 190(> i 527 

MIul( ( on^tan^ oj Natun Wishmgton 187} i, JO 

6 Rtt^cis /utuli itln^ihtl Chun 1S80 3 280 

' Kii(kin<y<i ibid 1800 21 5} 7 H u^h / imfi ( 1 hun S 

8 Htuniui /ulvh anon) Chun I004 38 J >() 

J St(fin \il HiH/^Ht A I///// II /ss If/o/ 1S71 63 |2] 2JM T 
7V/VS ISSO |0| 9 <)2 hold To////^ tuid lS05 I2O 140(> 
1002 \i\ 8 1 >0 Dufd />//// Sor //////r /I//// 1801 14 1 JO 

10 lii HIM /^/ 187^ 7 05S ll roiiKiii < o/;*/>/ n ml 

I Koi>j) AnnultH hiippl 1804 1805 3 i 280 

11 Rebuilt Pot/t/ Annalui 1841 53 00 24 J 

II Webci Aich S'ci ^%s wa 1805 [ J] 33 590 

16 Kopp, lor cit 16 Andicao / prakt Chcm 

17 Larlof Ucikcky Phil Trans 1904 [A] 203 200 

18 Iildcn and Shu atone ibid 1884 175 32 



1012 34 11 J7 
It \ -\)DI 



M nl( us (nti Physil 
1880 109 174 

1884 L-2J 29 407 



H4 OJf THE JfOTIOH OP HEAT. 

have the thermometer with its bulb in their 
genters* They were successively 6lkd with 
boiling water, and suspended in the middle of 
room of the temperature 4<y, and the times of 
cooling through each successive 10 degrees 
were noticed &s below. 



waw 


rcoo 




with piper 


nrnu 
cimiter. 


A-OJITH 
rtxx 


From 205 


to 


195 


m 65 mm 


1O mm 


11 


195 


to 


185 


7 


105 


13 


185 


tp 


175 


7 5 


1 1-f- 


IS 


175 


to 


16& 


8+ 


12 


13 


165 


to 


155 


9 


13.5 


14 


155 


to 


145 


10 


15 


16 


145 


to 


135 


11 5 


17 


17 


135 


to 


125 


13 


19 


19 


125 


to 


115 


145 


21 5 


29 


* J5 


to 


105 


10 


24 


25 


105 


to 


95 


20 


30 


2P 


95 


to 


85 


25 


38 


35 


85 


to 


75 


31 


46 


44 


75 


to 


65 


40 


f)O 


fki 



21P J27 



Here the results are equally satisfactory and 
important, not only the times ot cooling are 
in the uniform ratio of 2 to '\ throughout the 
range, but they almost exactly accord with 
the logarithmic ratios, indicating the geometric 
progression in cooling As experiments of 
this sort are capable of being repeated by any 
one without the aid of any expensive instal- 
ment or any extraordinary dexterity, it will 




ae car&lK>$ic aaa<i aaa6dic chambers ai^^jiiii^dLfcy a 
of porous clay, 7 the cathode being a rod of HT< *feo resist 1&e 
action of the caustic alkali, and the anode being of carbon to withstand 
the corrosive action of the chlonne 8 Hargreaves and Bird employ a 
cathode of iron gauze 

In the mercury process the bottom of the electrolytic cell is covered 
with a layer of mercury into which a non-porous diaphragm dips so that 
the mercury forms a partition between the anodic and cathodic chamber 
The anode is made of carbon, and is immersed in sodium-chloride 
solution , the cathode is made of iron, and is dipped into water The 
mercury acts as cathode, taking up the liberated sodium to form an 
amalgam, which reacts with the water to produce sodium hydroxide 
Various modifications of the process have been devised, one being the 
substitution of fused sodium chloride for the solution, and of fused lead 
or tin for mercury, the alloy produced being subsequently decomposed 
by water 10 

1 Heimbrodt Dissertation, Leipsic, 1903 , Graham, Zeitsch, physikal Chem 1904 
50 257 

2 Kohlrausch and Malt by Sitzungsber K ATcad Wiss Berlin 1899, 665 , Kohlrausch 
and Grotrian Pogg Annalen, 1875, 154, 1 , Kohlrausch, Holborn and Diesselhorst Wied 
Annalen 1898 64, 417 Walden, Zeitsch physikal Chem 1888 2, 49 , Arrhenms ibid , 
1892, 9 339 Krannhals ibid , 1890, 5 250 Schaller Landolt Bornstem and Meyer 
hoffer's Tabellen 3rd ed Berlin 1905, 755 , D6guisne Dissertation Strasbourg, 1895 
Noycs and Coolidge, Zeitsch physikal Chem 1903 46 323 Jahn ibid 1901 37 673 
1907 58 641 Schapire ibid , 1904, 49, 513 , Hittorf, Ostwald s Klassiker 21 23 

3 Karsten Philosophie der Chemie 1843 , Wmkelmann, Ann Physil 1873 149 492 
Mulder Scheikund Verhandel 1864 207 van t Hoff and Reicher Zeitsch physilal 
Chem 1880 3 482 Mackenzie Wied Annalen, 1877 I, 438 Sestschenoff Zeitech 
physiJal Chen 1889 4 117 Bohr Wied Annalen 1899 68 500 Gordon Zeitsch 
physiJal Chem 1805 18 1 Roth ibid , 1897 24 114 Knopp ibid 1904 48 97 
Sterner \\ led innaltn 1894 52 275 Braun Zeitsch physilal Chem 1900 33 721 
McFauchlin ibid 1 ( )(M 44 1)00 Gcftcken ibid 1004 49 257 Rothmund ibid 1900 
33 401 biltz ibid 1005 43 41 Fiikr ibid 1800 31 360, 1904 49 303 Levin 
ibid 1000 55 513 Dawson Ttans Chem Soc 1001 79 49* lOOb 89 605 Abegg 
and lluscnfdd Zfthch phy^Ictl (hem 1902 40 84 Raoult 4/ni Chun Phy* 1874 
|5] I 2(>2 GUIS Zidt^ch anorq Chun 1900 25 236 Ruscnfdd 7cit*ch physilal 
Chun 1002 45 4(>0, Konovvaloi? / Rn^ Phy> Chun SOP 1890 31 010 985 Jo \nnis 
Compt tuid 1801 112 JOJ Fo\ Zeitsch phyulnl (hem 1002 41 4>8 Kinnpf 
Wi(d Bu,M 1882 6 27(> Goodwin Ber 1883 15 3030 Kohn and () Bncn J /Soc 
Chun hid 18<)S 17 1100 

4 Schiff Annalui 186> 118 ^65 Gtiaiclm Ann Chim Pluj\ 1865 [4] 5 140 
Tobry do JJruyn tte( Irav chim 1802 II 147 Jmncbaiger Amcr Chem J 1804 
16 214 

r Richirdsind IOIKS J Amet (hem hoc 1009 31 158 

Compile (hit(\,hlclttochem Industrie Stuttgait 1896 112, loister Flektoochame 
wa*>MH}(r lovuM/c n I upsic 1905 385 

7 Hausscimann Zcifah angiw Chem 1894 7,0 Kcllmi ibid 1800 12,1080 

8 Jboistu /juMi ]<ldt)ochcm 1900 7 79i 

9 IT and Bird falttb JSleltrochem 1895 2 224 compaie lorstci and Jorre 
Zeitwh Jislthtrocliew 1003 9 206 

10 Compare Habcr Gtundnia techn Eleltrochem 1808 469 Zeitsch Elcltrochem 
1903 9,364 lorstcr, Mektrochemie wassnger Losunyen, I eipsic, 1905 427 

VOL II 7 



OH THE MOTIOH OF HSAT, 

S X 3 , this gives 1 * for the whole beat 
discharged by metal, and ifi for that dis- 
charged by glass in the same time, where the 
unit expresses the part conducted, and the 
fraction the part radiated 

That is, from a metallic surface 13 parts of 
heat are conducted away by the air and 1 part 
radiated, from a vitreous surface 13 parts 
are conducted, and 8 parts radiated, in a given 
time. 

The quantity of heat discharged by radia- 
tion from the most favourable surface, there- 
fore, is probably not more than 4 of the whole, 
and that conducted away by the air not less 
than 6 Mr Leslie however deduces 57 for 
the former, and 43 for the latter , because he 
found the disproportion in the times of cooling 
of vitreous and metallic surfaces greater than 
I find it in the lov er part of the sc lie 

Ihe obvious consequences ot this doctrine 
in a practical ^cnsc aic, 

1 In every case \\htrc lu it is required to 
be retained as long is possible, tlu < 

vessel should be ot metal, with a bright clear 
surface 

2 \\henever heit is required to be given 
out by a body with as much celerity as pos 
sible, the containing vessel, if of metal, ought 
to be painted, covered with paper, char- 



SODIUM 
SOI I nil I IT OF SODIUM BROMIDE, 



99 





Grams NaBr MS KW) 




Grams ISFaBr ua 100 


T< r i IK 


grains Water 


temperature, 


grams Water 


W O 




C 




v/ 


do Coppet 


3tad 




deCoppet. 


fewd 


-20 


714 


575 


50 


H6 


95 





795 


66 


60 


117 


112 


10 


845 


72 


80 


119 


118 


20 


903 


77 


100 


121 


114 


30 


978 


825 


120 


124 


116 


40 


1058 


88 


140 




118 



Meyerhoff er l has plotted the solubiht\ curv e (fig 6) The transition- 
temperature of the dihj drate into the anhydrous salt 2 (D) is 50 674 C , 
and that of the pentahydrate into the dihydrate (C) is 24 C 
























































































1 




















D 








/Va 


Bz 


' 


^^ 


****' 






CO 


















/ 
























ej 

* too 
















/ 


























g 












v\? 


^ 




























>- 
* on 










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^ 






























Q. 


N&B 


" ^. 


^** 


\^ 


































i 

fin 


SH 2 C 


V 






































g 

QQ 




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GO 






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B % 

<3 








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XI 
































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6 





6 





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Tern pet atuie 
JbiG Solubility cuivt of sodium biomult 

At its melting point the s lit loses onl\ i trace ol biominc, Imt heating 
\vith (\((ssol iodine induces i i ipid clnnin it ion of biominc 3 

Lun the he it ol foimitiou of sodium biomidc fiom its elements 

Beihn 1905 555 
Kick aids and Wells 



189 1 ) 28 J14 



1 MtycilioiTci landoU BonnUw and 

2 llidiinls ami Cluuc hill /jdhch phyul al them 

ibid 1 ( )00 56 348 compxrc Dawson andJackson, Trans Client hoc 190S 93 344 
a CJuaToscln Allill Accad Sci Torino 1913,48 735 



118 ON THE MOTION Of HEAT. 



which elapsed whilst the mercury 

from the upper to the under mark were then 

noted, as under The surrounding air was of a 

constant temperature 

Thermometer immersed 1 cooled in 
In carbonic acid gas .......... j 1 12 seconds. 

- sulphuretted hydrogen, w-'j 

trous oxide, and olefiant V 100 + 
gas ........ * .............. ) 

com air, azotic and oxyg gas 100 

nitrous gas ....... . ............ 90 

carburet hyd or coal gas *., 7O 

hydrogen ..................... 4O 

The refrigerating effect of hydrogen is truly 
remarkable, I cooled the thermometer 10 
times successively in a bottle of hydrogen gas , 
at each experiment the instrument was taken 
out, and the stopper put in, till the original 
temperature uas restored, by this, a portion 
of the hydrogen escaped each time, and an 
equal portion of common air was admitted, 
the times of cooling regularly mcrc-iscd as 
follows, viz 40,43, 46, 18, 51, 03, r >f>, 58, 
60 and 62 seconds, respectively , at this time 
the mixture was examined, and found half 
hydrogen and half common air Equal 
measures of hydrogen and common air were 




SchuUer 1 as 
0868 
6^ 08 CaL, 



tfvlubikty ofSodMm lod&de, T?aI,2H 2 O 
Solid Phase, Nat,2H 2 

Temperature, C 20 10 20 30 40 50 60 66 

Grams Nairn 100 g water 1480 1587 1686 1787 1903 2060 2278 2668 2784 

Sohd Phase, Nal 

Temperature, C 

Grams Nal in 100 grams water 



67 
293 



70 
294 



80 
296 



100 
302 



120 
310 



140 
321 



The solubility-curve (fig 7) is in conformity with the existence of a 
pentahydrate, the transition-point to the dihydrate & (Z>) being 13 5 C , 





































& 


























Ua./ 




f 




g 500 






















Y 


1 - 


!2&- 








250 




















/ 


f 












S3 




















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O 

**" *IQQ 
















ft 


^ 






























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^ 


















8 






p 


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^ ( 


-x ^ 






















o 




C 


y 




























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\$ 






























$ 




\ 






























! 




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-4 





-,2 


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9 


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81 


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10 








Temperature 

lia 7 Solubility curve of sodium iodide 

tint of the dihydidtt to the anhydious silt 6 (E) being 05 C The 
boiling point of d sdtui ited solution 7 in cont ict A\ith the solid is 14*1 C 
At 25 C 100 gi ims of ethyl alcohol dissolve 40 02 giams of sodium 

1 Schulltr Potjrj Annalui 1S69 136 70 235 

2 Rcgnault Ann Chim Phys 1841 [3] I 129 

3 Thomsen Thermochemistry (T ongmans 1908) 49 62 319 

4 See de Coppot Ann Chim Phys, 1883, [5J 30, 420 compaio Kremers, Pogg 
Annalen 1856 97 14 

5 Tanfiloff J Buss Phys Chem Soc 1893 25 262 

6 deCoppet Ann Chim Phys , 1883 [5] 30 425 

7 Gerlach Zeitsch anal Chem , 1869, 8 285 



J20 OK THB MOTION OF HEAT* 

ter as 1 78, fbm which he justly infers this 
inequality of effect [between atmospheric air 
and hydrogenous gas] proves its influence to 
be exerted chiefly, if not entirely, in augment* 
ing the abductive portion/* 

The expenditure of heat by radiation being 
the same m hydrogenous gas as in atmospheric 
air, we may infer it is the same in every other 
species of gas , and therefore is performed in- 
dependently of the gas, and is carried on the 
same in vacuo as in air Indeed Mr Leslie 
himself admits that the diminution of the 
effect consequent upon rarefaction is extremely 
small, which can scarcely be conceived if air 
were the medium of radiation 

The effect of radiation being allowed con- 
stant, that of the density of the air may be 
investigated, and will be found, I believe, to 
vary nearly or accurately as the cube root of the 
density In order to compare this Inpothcsis 
with observation, let 1()O - time ot cooling m 
atmospheric air, the density bung 1 , then 
from what has been said above, I- \\ ill represent 
the heat lost by a vitreous sari u e bj r uliation, 
and 6 that lost by the conducting power ot 
the medium Let / =- the tune <>t cooling in 
airof the density rf , thcnif KM) \ t <K)t 
/ = the heat lost by radiation but tin licit 
conducted away is, by hvpotl esis, ib the. tnri 



SODIUM. 

When the turbid liquid formed by ieatmg the ieptahydrate at 20 C 
is cooled slowfy t6 the ordaoatary ^e^peEratu^^. large ^&^k-ye]&w,^rexy 
dehqueseent crystals of tlte peata%fete a*e foied Thoy meft: at 
27 C , aod are stable at ordinary temperatoejai absence of aasr x 

Sodium hypochloxrfce is abo* iB^atufectujred by the electrolysis of 
sodium-chloride solution withotit a <Sb;pliragfla: (p 97), t&e solution beua^ 
less concentrated than that prepared by the eMonne process from sodium 
&ydfo>xide, but free from the excess of alkah characteristic of that 
prepared by the older method 2 The process is earned out either m the 
apparatus designed by Kellner, 3 or in that of Haas-Oettel, 4 sodium 
chlorate being a by product (v infra) It is noteworthy that electrolysis 
of sodium-chloride solution with an alternating current also produces 
sodium hypochlonte 5 

Thomsen 6 gives for the heat of formation of sodium hypochlonte m 
aqueous solution from its elements the value 83 36 Cal , Berthelot 7 
84 7 Cal For the molecular depression of the freezing-point in aqueous 
solution Raoult 8 found the value 3 38 C 

In aqueous solution sodium hypochlonte finds technical application 
in the bleaching of paper, linen, cotton, and straw In direct sunlight, 
concentrated solutions rapidly lose their activity Storage in colourless 
bottles accelerates the rate of decomposition, and in brown bottles 
retards it The stability of the solutions is much increased by com- 
plete exclusion of light 9 

Sodium chlorate, NaC10 3 When chlorine is passed into a hot 
solution of sodium hydroxide, the hypochlonte primarily formed 
changes into a mixture of chlorate and chloride, both salts crystallizing 
out 

2NaOH+Cl 2 =NaOCl+NaCl+H 2 , 
3NaOCl =NaC10 3 + 2NaCl 

The chlorate is purified from the chloride by fractional crystallization 
In Muspratt's method 10 magnesium oxide suspended in water is sub 
stituted for sodium hydroxide, the solution being concentrated after 
treatment with chlorine, and sodium carbonate added to precipitate the 
magnesium for further use The sodium chlorate ciystalh/cs from the 
mother-liquor The salt is also formed from potassium chlorate by 
double decomposition with substances such as sodium hydrogen tartiate 
and sodium silicofluoride, as well as by the electrolytic decomposition 
of sodmm-chlonde solution under certain conditions u (p 97) 

Sodium chlorate is a colourless, crystalline substance, and exhibits 
trnnorphism, forming ciystals belonging to the cubic, hexagonal, 12 and 

1 Applebey Trans CTiem Soc 1919 115, 1100 

Forstei Mekt) ochemie U abt>i ujw LOMUUJOI l(ipsic J9U5 341 Engclh licit Hypo 
chlorite und del ti Bleiche, Halle 1903 63 Mullci Zcihch hlcUiochcm 1899 5 409 
1900 7 398, 1902 8 909 German Patent 1890 No 104442 

J ECellnoi compare Roister loc cit 

I Haas Octtel Zcitsch 1 J Mttochtm 1900 7 >l r > Oettnan Patent, 1901, No 130345 
Coppadoro Oazzctta 1000 35 11 004 

( Phomsen, Theimochemi si/ y (Longmans 190b) 328 

7 Berthelot, Ann Clum Phy* 1875 [5] 5 338 

8 Raoult Compt rend 1881 98 509 

Bouvet Bull Soc Phannacol 1917 24 H7 
10 Muspratt Dingl Polytechn J 1884 254 17 

II Jborster, EleUrocliemie wab&nyer Losunycn, Lcipbic 1905 341 iLn^clhaidt, Hypo 
chlorite und eleltr Bleiche Halle, 1903, 03 

12 Retgers, Zeitsch Kryst Mm , 1894 23, 200 



122 Otf THB MOTIOH OF HEAT. 

if KXT 4 *: 40* - 16 = the heat lost by 
radiation in that gas in 4O seconds j whence 
,84 =? the heat conducted away by the air ia 
40"', or 021 per second* but m common ai* 
the toss per second bf abduction is ottly 006 ; 
from this it appears that the refrigerating 
power of hydrogenous gas is 3f times as great 
as that of common air 

It may be asked what is the cause why dif- 
ferent gases have such different cooling effects, 
especially on the supposition of each atom of 
all the different species possessing the same 
quantity of heat ? To this we may answer 
that the gases differ from each other in two 
essential points, in the number of atoms in a 
given volume, and in the weight or inertia of 
their respective atoms Now both number and 
weight tend to retard the motion of a current 
that is, if U\o gases possess the same number 
of particles in a given volurm , it is evident that 
one will disperse htat most quickly which has 
its atoms of the least weight , and if other 
two gases have particles of the same w( ight, 
that one will most disperse heat which has the 
least number in a given volume , because the 
lesistance will be as the number of particks to 
be moved, in hlce circumstance? Of the 
gases that have nearly the same number of 
particles in the same volume, are, hydrogen* 



of the 



The salt c#n also fce 
socbuxx hydroxide, but xt 
of a 25 per <?eat 




aeicl mtfe 
J>y the 

at 10 & C ? pla&jiuin electrodes 
a togt anode-potential beiftg &Lployed * Tlus process finds appkc^- 



the manufacture of potassium perchlorate, this salt being obtained 
sodium compound by the action of potassium chloride 

At ordinary temperature sodium perchlorate CT\ stalhzes as the very 
deliquescent monohydrate, but above 50 C as the anhydrous salt 2 Its 
deliquescent character hinders its technical application The melting- 
point 3 of the anhydrous salt is 482 C On heating, it is decomposed 
into chloride and oxygen s a proportion of chlorate being simultaneously 
formed 4 From cryoscopic experiments with sodium sulphate as 
solvent, Lowenherz 6 inferred the molecular formula to be NaCIO* 

For the heat of formation 6 from its elements, Berthelot gives 100 3 
Cal , and for the heat of solution 7 at 10 C , 3 5 Cal The electric con- 
ductivity has been investigated by Ostwald 8 and by Walden 9 

Sodium hypobromite, NaOBr When bromine reacts with sodium 
hydroxide in aqueous solution, sodium hypobromite is formed 

2NaOH+Br 2 =NaOBr+NaBr+H 2 O 

It is also a product of the electrolysis of sodium bromide without a 
diaphragm 10 (p 103) 

The salt has only been obtained m solution In this form it is an 
important oxidizer in analytical operations Foi the heat of formation 
of the dissolved compound from its elements, Berthelot n gives 82 1 Cal 

Sodium bromate, NaBr0 3 The bromate is formed by the action of 
bromine on a hot solution of sodium hydroxide, but is best obtained by 
the electrolysis of sodium bromide under certain conditions 

Like the chlorate, sodium bromate is tnmorphous, crystallizing in the 
cubic, 12 hexagonal, and rhombic 13 systems Its melting point 14 is 381 C 
For the density Krcmcrs 15 gives 3339, and Le Blanc and Rohland 16 
3 254 At 20 C , 100 grams of water dissolve 38 3 grams, and at 100 C , 
91 gi ims 17 The boiling point of the satuiated solution in contact with 
the solid is 109 C The compound finds application as in oxidizei 

References die appended to investigations of its optical properties 18 , 

1 WmUlci /eifoc// tk/tiochttn 1898 5 218 loistti, ibid 1898 4 380 

PotiliUin, J Jtn^ Phys Chcm Soc 1889 I 258 

( u m lit y and O Shea Tm/2* Chcm hoc 1884 45 409 

Scobu /ItituJi ptnjbikal Chun 1903 44 319 

lowcnhu/ ibid 1895 18 70, cumpaic liiits Tiant, Chem Soc 1895 74 59* 

Bciilulol Ann Chun Phyt> 1882 [5] 27 218 

Bcitbolot ibid 1875 [ r >] 4 li 

Ostwald Jehrbuch dcr allyim Chan 2nd cd , Leip&ic, 1893, 743 

Wildcn PeitKli pliytilal Chun 1888 2 49 

.Loiatcj J'lolhocht nne wawu/cr Lowtiyen Lcipsic, 1905 341 

Jit i tin lot Ann Chun Phyt. 1877 [ r >] 10 19 
1 lictgcis Zeihch Knjst Mm 1894 23 266 

13 Jirauns fahrb M^n , 1898 I 40 

14 C'aintllcy and Williams, Trant, Chew Soc 1880 37 125 
1 Krtmcis Pot/cj Annalen 1856 99 443 

1G Lo Blanc and Eohland, Zeitsch physil al Chcm 1896 19 261 

17 Kiemers Pogg Annalen 1855 97 5 

18 Traube Landolt, Bornstein, and Meyerhoffer's Tabdlen, 3id ed Bcilin 1905 706 



124 OH THE T&MFERATORE 

of great and extraordinary commotion in the 
atmospbeie, and is at most of a very short 
duration What then is ihe occasion of this 
diminution of temperature in ascending ? Be- 
fore this question can be solved, it may be pro- 
per to consider the defects of the common 
solution Aits it is said, is not heated by the 
direct rays of the sun , which pass through it 
as a transparent medium, without producing 
any calorific efiect, till they arrive at the sur- 
face of the earth The earth being heated, 
communicates a portion to the contiguous at* 
mosphere, whilst the superior strata in pro* 
portion as they are more remote, receive less 
heat, forming a gradation of temperature, 
similar to what takes place along a bar of iron 
when one of its ends is heated 

The first part of the above solution is pro- 
bably correct Air, it should seem, is singular 
in regard to heat , it neither receives nor dis- 
charges it in a radiant state , if so, the propaga- 
tion of heat through air must be cfRcted by its 
conducting power, the same as in water 
Now \*e know that heat applied to the under 
surface of a column of viatcr is propagated 
upwards with great celerity, by the actual 
ascent of the heated particles it is equally 
certain too that heated air ascends From 
these observations it should follow that the 



SODTOM. 

tffadwm 
Temperature, C 25 



A cold, aqueofcs solutton ^scwftHm>y(&o^.de converts : %s salt into the 
perwdate of the formula Na^-fO^ ^fjjbese t#o substaaees are the osoly 
p&xodates of sodium ki*own to ^xigfc m axjo^ous solution The optical 
p^seopertieis * and electric cou-dj^cS^ty ra aqueous solution 2 of the 
o^sodnm^ salt l*ave been investigated 

Otter peraodates have been described by Walden 2 and by Muller s 
Sodium manganate and permanganate - The modes of preparation 
and the properties of sodium manganate and permanganate are given 
mVol VIII 

Sodium monoxide, Na 2 The monoxide is produced by combustion 
of sodium in dry an*, the peroxide being formed simultaneously , or by 
heating the hydroxide or peroxide with sodium 4 

2NaOH+2Na =2Na 2 O +H 2 

Sodium monoxide is a white substance when cold, pale-yellow when 
hot, and melts at bright redness It is very hygroscopic, combining 
with water to form the hydroxide, the heat evolved being 56 5 Cal 5 
For the density Beketoff 6 gives 2 314, and Rengade 7 2 27 The heat 
of formation from the elements is 100 7 Cal 8 Above 400 C it yields 
equimolecular proportions of sodium and sodium peroxide It is con- 
verted by hydrogen into an equimolecular mixture of sodium hydroxide 
and hydride, and it also combines with fluorine, chlorine, and iodine 

The so called " sodium suboxide," obtained by combustion of sodium 
in a limited supply of oxygen, seems to be either a mixture or solid 
solution of sodium and sodium monoxide 

Sodium peroxide, Na 2 2 The peroxide is manufactured by the 
action of dry air, free from carbon dioxide, on sodium 9 m an iron tube at 
300 C , 10 the only process employed for its production on the large scale 
The commercial article contains about 93 per cent of sodium pei oxide 

Sodium peroxide has a yellowish colour It is not decomposed by 
heat, but is a very powerful chemical reagent, m many respects re 
semblmg hydrogen peroxide 

It can act as a reducer, 11 decomposing salts of silvci, gold, and 
mercury, with evolution of oxygen As an oxidizer, it icacts energetically 
with silver, tin, and lead It converts the oxides of carbon into sodium 
caibonate, and nitrogen monoxide and nitric oxide into sodium mtiatc 
It is reduced to sodium 12 by charcoal or carbides of the alkaline caith- 

1 (Jioth Pogy Atmaltn 1869 137 433 

Walden Zeitsch physikal Ghent ,1888 2 49 
> Muller Zeit&ch LleLtrochem 1901 7,509, 1904 10 49 

4 Badischo Amlm und feoda iabnk, German Patent No 147933 Rengade, Cornet 
rtw/,1906 143 1152 1907 144 753, Ann Chun Pliy\ 1907 [8] n 424 

Ilcngadc Compt rend 1908 146, 129 Bull Soc chim 1908 [4J 3 190, 194 
' 13ikctofl J Huts 7%& Chem /S'oc 1887 I, 57 

7 Ucngadc, Compt rend , 1906 143 1152 1907,144 753 Ann Chim Pliys 1907 
[8J II 424 

8 Ucngade, Compt rend, 1908, 146, 129, Bull Soc clnm , 1908 [4] 3 190 194 
dc Foiciand, Compt rend , 1914 158, 991 

J Castnoi, J Soc Chem Ind 1892 n, 1005, compile Gay Lussac and Thcnaid 
Hediei dies physico chinnques Paris, 1811 

10 Castner, British Patent, 1891, No 20003 

11 Poleck, Ber , 1894, 27 1051 

12 Bamberger, Ber , 1898, 31, 54 



CM TEE TEMTERATURtt 

It is an established principle that any body 
on thesarfece of the earth unequally heated m 
observed constantly to tend towards an equality 
of temperature , the new principle announced 
above, seems to suggest an exception to thi 
law. Bat if it be examined, it can scarcely 
appear m that light Eguahty qf heat and 
equality qf temperature, when applied to the 
same body in the same state, are found so 
uniformly to be associated together, that we 
scarcely think of making any distinction be- 
tween the two expressions No one would 
object to the commonly observed law bemg 
expressed m the^e terms When any body is 
unequally heated, the equilibrium i? found to 
be restored when each particle of the body 
becomes in possession of the same quantity of 
heat Now the law thus expressed is what I 
apprehend to be the true general law, which 
applies to the atmosphere as well as to other 
bodies It is an equality of In at, and not an 
equality o f temper atun that nature tends to 

restore 

The atmosphere indeed presents a striking 
peculiarity to us m regard to heat we see in 
a perpendicular column of air, a body without 
any change of form, slowly and gradually 
changing its capacity for heat from a less 



SODIUM: 



de Forcraiid 1 m^atKms two otter s&ifamn, per$mde$ t Na 2 O 3 and 
Na 2 O 4% The &eat of fbi^a^ 



So^Bfcm hydroxide, NaOH^^^dShe pare hydroxide ea#.4>e p 

by dissomag r ^^8in m Ttfater a^id ^vaporafi^ the 
or by the eleetro^S^^i^^Mafnieroial socbona Jhydroxaae HI 
solution with a mrf^^^^t!hode, the amalgam formed being 
A sojdikm free from earboiiate can be obtained 
laix>ra%c*y by suspending metallic sodium in a layer of ether 
ort the surface of \v ate r 1 he metal dissolves slowly in the water 
present m the ether, and the sodium hydroxide passes into the bottom 
aqueous layer 4 The hydroxide is manufactured by the electrolysis of 
a solution of sodium chloride (p 97) , and, according to van Laer, 5 
an economical yield can be obtained directly by the electrolysis with a 
suitable diaphragm of a solution of sodium carbonate containing nitrate 
or sulphate of sodium to hinder the formation of sodium hydrogen 
carbonate Sodium hydroxide is also produced industrially by the 
much older method of decomposing sodium carbonate with slaked lime, 
a reversible reaction 6 

Na 2 C0 3 +Ca(OH) 2 ^= 2NaOH+CaC0 3 

The solution of sodium hydroxide is evaporated m iron vessels, the 
finished product being marketed in the form of sticks or powder, or m 
cylindrical blocks of about 6| cwt enclosed in iron drums Slaked lime 
also decomposes sodium sulphate with production of sodium hydroxide, 
and the effect on the yield of the temperature and the dilution of the 
solution has been studied by Neumann and Karwat 7 

Sodium hydroxide is a white substance of density 8 2 130 It dis 
solves readily m both water and alcohol It is very stable, melting 9 at 
318 4 C and at a higher temperature volatih/mg without decomposi 
tion Admixture with other substances lowers the melting point 10 The 
mixture containing 58 4 per cent of potassium hydroxide melts at 
167 C , that with 20 7 per cent of a mixture of 48 5 pel cent of sodium 
carbonate and 51 5 per cent of potassium carbonate at 265 C , and that 
with 17 per cent of sodium carbonate at 280 C For the latent heat 
of fusion per mol , Ilevcsy n gives 1 602 Cal Its hygroscopic charactci 
causes it to liquefy on exposure to in, but it is converted into solid 
carbonate by the action ot atmospheric carbon dioxide The pei 
centage of water in fused samples vanes between 9 and 1 2, the 
average being II 12 

1 dc I'orcrand Compt rend 1914 158 84] 991 

Compare Kuster Zeitsch anory Chun 1901 41 471 
* JoiissenandFilippo Chim Weekblad 1900 6 145 
4 Cornog J Amer Chem Soc 1921 43 2573 

vanlaci J Chttn phyi 1917 15 l r >4 

( Bodlandcr Zeitwh Mcktrochan 1903 12 ISO It Llxnc ind Novotny 7eii^cl\ 
anorg Chem 190C 51 Ibl 1907 53 347 Wegscheidei and Walt ci inmihrt 1907 
351 87 Monateh 1907 28 543 555 (>33 

7 Neumann and Kaiwat Zeitsch Elektrochem 1921 27 114 

8 iilhol Ann Chim Phys 1847 [3] 21 415 

9 Hevesy Zeitscli phynkal Chem 1910 73 607 

10 Neumann and Bergve Zeitsch Fhlttochew 1914 20 271 

11 Hevesy Zeitsch phynkal Chem 1910 73, 007 

12 Wallace and Fleck Trans Chem Soc , 1921 119 1839 



OH THE 



to the same temperature as the 
roiindiftg air ; or mce* versa, if two measure* 
of air at die proposed height were condensed 
into one measure, their temperature would be 
raised 50% and they would become the same In 
density and temperature, as the like vokime of 
atr at the earth's surface* In like manner we 
may mfer, that if a volume of air from the 
earth's surface, to the summit of the atmo- 
sphere were condensed and brought imo a 
horizontal position on the earth's surface, it 
wouM become of the same density and tem- 
perature as the air around it, without receiving 
or parting with any heat whatever 

Another important argument in favour of 
the theory here proposed may be derived from 
the contemplation of an atmosphere of vapour 
Suppose the present amal atmosphere were to 
be annihilated, and one of steam or aqueous 
vapour were substituted in its place , and sup- 
pose further, that the temperature of this at- 
mosphere at the earth's surfdcc were every 
where 212 and its weight uju d to JO inches 
of mercury Now at the elevation ot about 

6 miles the weight would be 15 inches or 
\ of that below, at 12 miles, it would be 

7 5 inches, or \ of that at the surf ict, &x and 
the temperature would probably dimmish 25 
at each of those intervals It could not di- 



SOBltM 

monohydrate melts at $4 3 Por its cteajsrty Gerlach * gives 1 829 
At 12 C it is transformed 2 aato the ijfliydrate, ^teet t a eoaoente- 
taoia of 45 5 per cent of g&$&w&. IgrdjrQx^fe BS HI &qE^fegr$&^ at ^^ C 
-with a 3 5 hyebate, 2N^OB^I^0^ ^ jss afeo the a-t^t^^dS^fce at tfe.e 
same temperature aa<J a co^cm^tion. of 32 per cemfc, of sodium 
hydroxide. At 177 C tie a^&d$&fej$2&& changes to the penta- 
hydrate, and this form at 24 C? to the heptahydrate The saturated 
solution HL contact with the sohd boife at 314 C 3 

..The specific heat of the anhydrous hydroxide is given by Blumcke 4 
as 78 between and 98 C The mean molecular refraction of the 
molten hydroxide between 320 and 440 C is 5 37 6 The heat of forma- 
tion from the elements is given by de Forcrand 6 as 103 10 Cal , and that 
from the solid monoxide and hquid water as 36 50 Cal For the former, 
Rengade 7 gives 101 9 Cal , and in solution 1118 Cal , for the heat of 
formation in dilute solution from sodium and water he gives 44 1 Cal 
The heat of solution is given by Thomsen 8 as 9 94 Cal , and by Berthelot 9 
as 9 8 Cal The heat of dilution has also been studied by both these 
investigators The heat of formation of the monohydrate is given by 
Berthelot as 3 25 Cal The heat of neutralization of the hydroxide by 
mineral acids has been investigated by Richards and Rowe ia 

At ordinary temperatures an aqueous solution of sodium (or potas- 
sium) hydroxide dissolves sulphur, forming sulphide, polysulphides, 
thiosulphate, and sulphite The reaction is very complex, but Calcagm n 
thinks that the sulphide is probably formed first, thiosulphate next, and 
then polysulphides Finally, sulphite is produced by decomposition of 
the thiosulphate With concentrated solutions part of the sulphur 
probably dissolves without entering into combination Ammonium 
hydroxide of density 888 behaves similarly u 

When heated in copper vessels at temperatures between 350 and 
600 C in contact with air, sodium hydroxide has been observed to 
dissolve up to 73 per cent of its weight of copper The action on 
iron is less, and on nickel least of all 12 

Other properties of aqueous solutions have been studied, such as 
the density, 13 vapour pressure, 14 boiling point, 15 moleculai depicssion 
of the fiec/ing point, 16 electric conductivity, 17 electrolytic dissociation, 18 

1 Gerlach Jahrc^bencht 1886 69 Compare Hermes, Annakn 1861 119 170 

3 Gerlach, Zeitsc h anal Chem 1887 26 41 } 

4 Blumckt Wied Annalen 1885 25 417 

5 G Meyer and Heck Ze^tsch Elektrochem 1922 28, 21 
do lu>i crand Ann Chim Phys 1908 [8] 15 433 

7 Rengade Compt tend, 1908, 146 129 Bull Soc chtni 1908 [4] 3 190 194 
9 Thomsen Therwoch( mistry (Longmans 1908) 49 

9 Berthelot, Ann Chim Phys 1875 [5] 4 521 

10 Kichaids and Rowe J Amer Chem Soc 1922 44 684 

11 Calcagm Guzzettu 1920 50 u 3U 

1 Willacx intmocl 1 ian,<* Chem Hoc 1921 119 1839 

13 Pickciing Trans Chem tioc 1893 63 890 Foich Wicd innnltn ISO") 55 100 
Wegscheider and Walter Monuhh 1906 27 13 

14 Dieteiioi, Wied Annalen 1891 42 513 Tamminn ibid 1885 24 530 Mem 
Acad St Petersburg 1887 [7] 35 No 9 

15 Geilach Zeitsch anal Chem 1887 26 413 
10 Loomis Wied Annalen 1897 60 532 

17 Loomis, loc cit Kohlrausch and Holboin Lcitimnogen (hi Flcltrolyte I eipsic 
1898, Foster Physical Rev 1899 8 257 Demohs J CJntu phys 1906 4 520 Runz 
Zeitwh physilal Chem 1903 42 591 Bern ibid 1898 27 1 28 439 Kuschcl Wied 
Annalen 1881 13 289 

18 Arrhemus, Zeitsch physical Chem , 1892, 9 1339 



J30 OK THE TEMPER ATtTRE 

a perfect equilibrium having once obtained, 
there could be neither condensation nor eva* 
poration in any region. For every 400 yards 
of elevahon, the thermometer would descend 
1 degree 

2 If the atmosphere were constituted just 
as above, except that the temperature now 
diminished more rapidly than at the rate of 
25 for 6 miles , then the temperature of the 
higher regions not being sufficient to support 
the weight, a condensation must take place $ 
the weight would thus be diminished, but as 
the temperature at the surface is always sup- 
posed to be kept at 212% evaporation must go 
on there with the design to keep up the pres- 
sure at 30 inches Thus there would be per* 
petual strife between the recently raised vapour 
ascending, and the condensed drops of ram 
descending A position much less like!) than 
the preceding one 

3 The same things being supposed as be- 
fore, but now the temperature decreases more 
slowly than at the tate of 25 for f> miles m 
this case the density of the steam at the earth's 
surface would be a maximum for the tempera- 
ture, but no where else , so that if a quantity of 
water were taken up to any elevation it would 
evaporate , but the increased weight of the 
atmosphere \\ould produce a condensation of 



SODIUM. 113 

Four hydrates have been described by Parxaraao and Fornami, 1 
containing respectively 9, 6, 5J, and 5 molecules of water T&e penta- 
hydrate was also prepared by B5ttger 2 by adcb&g aj^dbol to a solution 
of sodium hydroxide saturated with hydrogen sulphide Sabatier 3 
mentions a 4^-hydrate, obtained by drying the 9-hydrate over sulphuric 
acid 

The solution of the sulphide HI water has an alkaline reaction due to 
hydrolytic dissociation Atmospheric oxygen converts the dissolved 
sulphide into thiosulphate, and electrolytic oxidation yields the sulphate 
The solution dissolves sulphur, forming polysulphides 

The melting-point of sodium monosulphide is 920 C 4 For the 
anhydrous salt the density is given by Filhol b as 2 471, a modern 
determination by Rengade and Costeanu 6 being 1 856 The heat of 
formation from its elements is given by Sabatier 7 as 88 2 Cal ? and by 
Rengade and Costeanu 8 as 89 7 Cal The investigators last mentioned 
found the heat of solution to be 15 5 Cal The heat of hydration of the 
anhydrous salt to the 9 hydrate is 31 72 Cal For the heat of formation 
in aqueous solution from the elements, Thomsen 9 gives 101 99 Cal 

In aqueous solution sodium monosulphide reacts with iodine to form 
sodium iodide, the liberated sulphur dissolving in excess of the sulphide 
solution 10 A double sulphide of the formula Na 2 S,Cu 2 S has been 
prepared n It melts at 700 C 

Other investigations of solutions of sodium sulphide include the 
concentration of the hydroxyl-ions and the depression of the freezing- 
point, 12 the solubility of ammonia, 13 and the density 14 

Sodium polysulphides 15 According to Thomas and Rule, 16 the whole 
series of polysulphides Na 2 Saj exists, x being a whole number with the 
maximum value 5 Their results obtained by the ebulhoscopic method 
m alcoholic solution favour the simple formula Na 2 Sa. as against Na^ 
On the other hand, Fnedrich 17 claims to have prepared polysulphides 
with the formulae indicated, the melting points being given in brackets 
Na 4 S 3 (772 C ), Na 2 S 2 (445 C ), Na 4 S 5 (345 C ), Na 2 S 3 (320 C ), Na 4 S 7 
(295 C ), Na 2 S 4 (255 C ), Na 4 S 9 (210 C ), and probably Na 2 S 5 (185 C ) 

Bloch and Hohn 18 have prepared solutions containing the disulplnde 
Na 2 S 2 , tnmlphide Na 2 S 3 , tett asulphide Na 2 S 4 , and pentasulplnde Na 2 S 5 

1 Parravano and Fornami Atti R Accad Lincei 1907 [5] 16 n 464 Gazzetta, 
1907 37 n 521 

2 Bottger Annalen 1884 223 335 

1 Sabatier Ann Chim Phys 1881 [5\ 22 66 

4 Inednch Metall ntid Erz 1914 IJ^.79 * u ^ ^ j * 

1'ilhol Ann Clum PTtgebWJff f3] 21,415 
Kt ng idc and C ostcaml Gompt rend 1014 158 940 

7 Sxbatici Awn Chim Phy? 1881 [5] 22 1) 

8 Re ngaclc and Costeanu loc cit 

9 Thomsen Thermochemistry (Longmans 1908) 322 

10 1'hrhch Zeitwh anal Ghem 1918 57 21 

11 Liudnch loc cit 

1 Kuster and Ht beilem Zeitt>ch anojg Chew 190 r > 43 53 compile Kohchen 

Zcitsch i>7iysikal (hem 1900 33 173 Knox ZeitwJt flclttodicm 1000 12 477 

13 Ab( gg and lliesenfeld Zeitwh phytikal Chew 1902 40 S4 H \oiilt ^1???? Chun 
Phy* 1874 [5] I 202 Gaus Zfihcli anoig Chetn 1900 25 2^0 

14 Bock Wied Innalen 1887 30 631 

1 On the constitution of the polysulphides see this series Vol \ IT Kuster Zeitwh 
anorq Clicm 1905 44 431 46 113 Kuster and Heberltm ibid 100* 43 53 
lr Thomas and Rule. Trans Ghent Soc 1917 in 10(>3 
17 Fnednch, loc at 
^ Bloch and Hohn Ber 1908 41 1961 

VOL II S 



1S2 OH THE TEMPERATURE, &C, 

Tbatan atmosphere of steam does actually 
surround the earth, existing independently of 
the other atmospheres with which however it 
is necessarily most intimately mixed, is I thmk 
capable of dc monstfation I have endeavoured 
to enforce and illustrate it in several Essays in 
the Memoirs of the Manchester Society, and 
an Nicholson's Journal, to which I must refer 
Now an atmosphere of any elastic uid, 
whether of the weight of SO inches of mer- 
cury, or of half an inch, must observe the same 
general laws, but it should seem that an 
atmosphere of vapour vanes its temperature 



condensations, though it may be nearly so for moet of them 
towards the conclusion, the space occupied by the solid 
atom or particle bears a considerable proportion to the whole 
pace occupied by it and its atmosphere At the first com- 
pression, the atmosphere of heat might be said to be re- 
duced tnto half the space , but it the lost, the reduction 
would be much greatu, and theiefore moie heat given out 
than determined by tlreory 

Since writing the alxw Mr Fw trt informs me* that th/j 
idei respecting stcarn, which I hid from him, is originally 
Mr Watt's In Black's Ixtturti, Vol 1 page* 1'JO, the 
tuthor, speaking of Mr Watt's txpenments on steam at 
low tempeiatuus, observes, " we find thit the latent heat 
of the steim is at least as much increased as the visible 
heat is diminished " It is wonderful that so remarkable a 
fact should have been so long known and so little noticed 



SODIUM. 11$ 

It is a white, crystalline solid, very deliquescent, freely soluble in water, 
aad moderately soluble in alcohol When exposed to air it evolves 
Irulrogcn sulphide, 1 and is completely decomposed by heat into this 
gas and sodium monosulphide 2 The anhydrous salt is also obtained 
by the interaction at 300 C of sodium monosulphide and hydrogen 
sulphide free from carbon dioxide and oxygen 3 Sabatier's 4 method is 
to saturate a solution of sodium sulphide with hydrogen sulphide^ and 
concentrate in an atmosphere of the same gas A solution caa be 
obtained by saturating sodium-hydroxide solution with hydrogen 
sulphide A dihydrate and a tnhydrate have been described 5 

The heat of formation of the solid from the elements is given by 
Sabatier as 55 7 Cal , that in solution by Thomsen 6 as 58 48 Cal , and by 
Berthelot 7 as 60 7 Cal For the heat of solution of the anhydrous salt 
at 17 5 C Sabatier gives 4 4 Cal , and for that of the dihydrate -1 5 Cal , 
it follows that the heat of hydration of the dihydrate is 5 9 Cal 

The preparation in solution of a compound of the formula NaOSH 
has been described by Gutmann 8 

Sodium sulphite, Na 2 S0 3 The anhydrous sulphite can be prepared 
by heating equimolecular proportions of sodium hydrogen sulphite and 
sodium hydrogen carbonate 9 

NaHS0 3 +NaHC0 3 =Na a S0 3 +H 2 0+C0 2 

It is also precipitated by the action of ammonia on a solution 
containing sodium chloride and ammonium sulphite in equimolecular 
proportions 10 Hartley and Barrett n have described a method of 
preparation from sulphur dioxide and sodium carbonate It is a 
white, crystalline sn.lt 

For the solubility of this substance in 100 grams of water at 20 C 
Kremers 12 gives 28 7 grams , at 40 C , 49 5 grams , and at 100 C 
Fourcroy 13 gives 33 grams At 10 C the heat of solution 14 of the 
anhydrous salt is 2 5 Cal 

Hartley and Barrett u state that the only stable forms are the an- 
hydious salt and the hcptahydrate, Na 2 SO 3 ,7H 2 O Neithei they noi 
Sohultz-Scllack 15 could isolate the decahydrate described by Muspratt 16 
The \nhydrous salt belongs to the hexagonal system, *nd at 15 C his 
the density 2 6334 The hcptihydiatc is monoclimc, its density at 
15 C being 1 5939 At 10 C the heat of solution of the hcptihydiatc 
according to de Porcrand 14 is 11 1 Cal , and the heat of hydiatum 
13 6 Cal 

1 Jlulo Trans Chem Soc 1911, 99 558 

Ihomis and Ruli ibid 1013 103 871 

3 Verem Chemischci iabnkenm Minnluim German Patent, 1008 No 194882 
1 Sibaticr Ann Chim Phys 1881 |5] 22 15 

Bloxam Tran* Chem Soc 1900 77 753 
' lliomsui rhprtnochLtm&try (Longmans 1908) 322 

7 Boithelot Ann Glum Phys 1875 [5] 4 100 

8 Gutmxnn Bu 1008 41 ^51 

9 Payello and feivler German Patent No 80390 

Diesel and Lennhof ibid No 80185 compiro Duvieusart ibid 1909 No 21080t 

Hutlcy and Banett Trans Chem Soc 1909 95,1178 

Kiemers Pofj</ Annalen 1856 99 50 

FOUL cioy Comey <* Dictionary of Solubilities London 1896 464 

dc Forcrand Ann Chim Phy* 1884 [G] 3 243 
" Schultz Sellack / prakt Chem , 1870 [2], 2, 459 
16 Muspratt, Phil Mag , 1847, [3], 30, 414 



1S4 O 

1 The specific gravity of ice is less than that 
of water m the ratio of 92 to 100. 

$ When water is exposed m a large sus- 
pended jar to cool in still air of 20 or 30*, it 
foay be tooled 2 or 3* below freezing , but if 
any tremulous motion take place, there appear 
instantly a multitude of shining hcxangular 
spicule, Soaring, and slowly ascending in the 
water 

3 It is observed that the shoots or ramifica- 
tions of ice at the commencement, and in the 
early stage of congelation are always at an 
angle of 60 or 120 

4 Heat is given out during congelation, as 
much as would raise the temperature of water 
150 of the new scale The same quantity is 
again taken in when the ice is melted This 
quantity may be ,V of the whole heat which 
water of 32 contains 

5 Water is densest at 36 of the old scale, 
or 38 of the new from that point it gradu- 
ally expands by cooling or by heating alike, 
according to the law so often mentioned, that 
of the square of the temperature 

6 If water be exposed to the air, and to 
agitation, it cannot be cooled below 32 , the 
application of cold freezes a part of the water, 
and the mixture of ite and water requires the 
temperature of 32 



* ^* OTt-r-1^' ^ ^ H 

SOPIUM 117 

solution, an illustration of has difficulty be$ag the identity in their 
electric conductivities Since both i$oi&eKte tn^ght yield the same 
ions, Earth's evidence is inconclusive , but fej& work on the mercury 
salts appears to confirm th$ assiimpteoia of the sulplnmic formula. 

Schwicker claimed to have prepared distinct derivatives by the actton 
of ethyl iodide, but a repetition of his work by Fraps x led to negative 
results Arbusoff 2 mvestigated the interaction of methyl iodide 
and the double sulphites obtained by Schwicker's method, the sodium 
atom in each instance being replaced by a methyl group, with formation 
of the same compound, 

CH 3 SO 8 K 

If two isomendes do exist, that with potassium attached directly to 
sulphur must be unstable, and change readily into the isomeric form s 

Sodium pyrosulphite, Na 2 S 2 5 When excess of sulphur dioxide is 
passed into sodium-carbonate solution at low temperature, anhydrous 
sodium pyrosulphite separates 4 , at ordinary temperature the hydrate 
Na 2 S 2 O 5 ,JH 2 O is formed 5 This substance may be regarded as an 
anhydride of sodium hydrogen sulphite 2NaHSO 3 H 2 O=Na 2 S 2 6 
The heat of formation of the anhydrous salt from its elements is given by 
de Forcrand 6 as 348 4 Cal , and the heat of solution at 10 C as 5 2 Cal 
The electric conductivity has been investigated by Walden 7 The salt 
is employed to retard oxidation of photographic developers 

Sodium sulphate, Na 2 SO 4 The sulphate is often called " Glauber's 
salt," on account of its application in the seventeenth century as a medi- 
cine by the physician Glauber, the specific being known as " sal mirabile 
Glauben " Its purgative action seems to be a phenomenon dependent 
on osmosis 

The anhydrous sulphate is a constituent of oceanic salt deposits, 
and is called thenardite An isomorphous mixture with potassium 
sulphate is known as glasente , a double salt with magnesium sulphate 
as astrakanite, and with calcium sulphate as glaubente 

Sodium sulphate is an intermediate product in the manufacture of 
sodium carbonate by the Le Blanc process (p 143) It is also a by 
product in the manufacture of nitric acid by the interaction of sodium 
nitrate and sulphuric acid 8 

2NaNO 3 +H 2 S0 4 =Na 2 SO 4 +2HNO 3 

In the Stassfurt deposits sodium chloride and magnesium sulphate 
monohydrate or kiesente are present, and on cooling the solution to 
3 C sodium sulphate crystallizes out A mixture ot sodium chloride, 
magnesium sulphate, and sand also reacts at dull red heat to form 

1 traps Amu Chun J , 1900 23 202 

Arbusoff J Ru&s Phy^ Chem Soc, 1909, 41 447, conipxie Godby Ptou Chem 
Soc 1907 23 241 

3 Gaiiott (Trana Chun boc 1915, 107 1324) mcasuied the molecular extinctions 
of solutions of the ifeoinendcs but found no selective ab&oiptiun, so that hi& method gave 
inconclusive results 

4 Schultz Pogy 4nnalen 18G8 133 137, oompaio Caiey and Huitei, Bnlish Patent, 
1882 No 4512 

6 Kohng Gmdin Kraut, and Fnedhcini A Handbuch der anoty Chun 7th ed 1906 2, 
i 321 

6 delorciand Ann Chim Phys 1884 [6], 3 243 

7 Walden, Zeitsch physilal Chem ,1887 I 529 

8 See this series, Vol VI 



130 OH CONGELATION. 

stratum of particles placed upon these in like 
order of squaiss, but so that each globule falls 
iBto the consavitj of four others on the first 
stratum, and consequently rests upon four 
pomte, elevated 45* above the centres of the 
globules A perpendicular section of such 
globule nesting upon two diagonal globules of 
the square is exhibited in Fig 3 Conceive 
a third stratum placed in like manner upon the 
second, &c. The whole being similar to a 
square pile of shot The above constitution 
is conceived to represent that of water at the 
temperature of greatest density 

To find the number of globules m a cubic 
vessel^ the side of which is given , let n = the 
number of particles in one line or side of the 
cube , then if is the number m any horizontal 
stratum , and because a line joining the centres 
of two c ; ** particles in different strata 

makes an angle of 45 with the hon/ontal 
plane, the number of strata m the given 
height will be n sine of 45 = n \\/<l 
Whence the number of particles in the cubic 
vessel = ?i 3 -JV 2 == wV'J 

Now let it be supposed that the square pile 
is instantly drawn into the shape of i rhombus 
(Fig2 ) ,then each horizontal stratum vuil still 
consist of the same number of particles as be- 
fore, only in a more condensed form, each 



SODIUM. 119 

tion is 31 38 Cal , and for the heat of solution of the anhydrous sulphate 
he found 46 Cal l For the heat of solution of the deeahy4rate Thorn- 
sen 2 gives 18 8 Cal , and Berthelot* 18 I CaL The heat of hydration 
of the anhydrous salt to the decahydrate is given by Thomsen s as 19 22 
Cal , and by Berthelot 3 as 18 64 Cal 

* The solubility of the anhydrous salt diminishes with nse of tempera- 
ture from 33 to 120 C , as indicated in the table of solubility* 



Solubility of Sodium Sulphate 
Solid Phase, 



Temperature, 10 20 30 32 75 

Grams Na a S0 4 in 100 grams water 50 90 19 4 408 50-65 

Solid Phase, NagSO^THaO 

Temperature, C 5 10 15 20 25 

Grams Na^O* in 100 grams water 19 5 24 30 37 44 53 

Solid Phase, Na 2 S0 4 

Temperature C 33 35 40 50 60 80 100 

Grams Na 2 S0 4 in 100 grams water 50 6 50 2 48 8 46 7 45 3 43 7 42 5 

Temperature, 120 140 160 230 

Grams Na 2 S0 4 in 100 grams water 41 95 42 44 25 46 4 

Lowel 4 gives the transition-point of the heptahydrate into the anhydrous 
salt (E) as 24 4 C , and that of the decahydrate into the anhydrous 
salt (F) is given by Richards and Wells 5 as 32 383 C , and by Dickinson 
and Mueller 6 as 32384 C The solubility relations are graphically 
represented in fig 9 (p 120) 

A saturated solution of sodium sulphate containing 42 2 giams of 
sulphate per 100 grams of water boils at 101 9 C at 751 mm pressure, 7 
or 108 668 C at 760 mm pressure 8 

Sodium sulphate readily forms a supersaturated solution in water 9 
When a solution is cooled to about 5 C , the heptahydrate crystallizes 
out The crystals of the decahydrate weather in air, owing to loss of 
water of crystalh/ation 

Reduction of sodium sulphate with charcoal at red heat produces 
sodium sulphide and carbon monoxide, along with sodium poly sulphides 
and caibon dioxide Addition of alcohol to a solution of sodium 
sulphate in aqueous hydrogen pei oxide precipitates a complex derivative 
of the foimula Na 2 SO 4 ,9H 2 O,H 2 O 2 1J 



1 Ihoinscn, J ptaLt Chun 187b [^J *7 173 comp Lie Pickoim^ l ] tunt> Chem Soc , 
1884 45 686, Bcithelot diul llosvaj, Ann Chun Phy* Ibb3 [^>] 29,330 

Thom&en, loc cit 

3 Bcithelot, Ann Chun Phys 1875, [5] 4 106 
* Lowel ibid 1857 [3] 49 50 

Kichaids and Wells Zettsch pliytikal Chun 1 ( J03 43 -471 
G Dickinson and Muellci J Ame> Chun /Soc 1907 29 Ulb 

7 Fail of Bcikcky Phil Trutu> 1904 [Al 203 200 

8 lLarl of Beikcley ind Applcboy P)oc Roy ;Soc 11)11 [AJ, 85 ts<> 

9 Compare Ostwald, Principles oj Inortjanic Chunistiy (Macimllan 1904) 402 
10 Tanatar, Zeitsch anorg Chem , 1901, 28 255 



138 0tf CONGELATION. 

this reduces the specific gravity of ice 2 p 
<#nt or makes it 92, which agrees exact 
with observation. Hence the 1st fact is e 
plained 

The angle of a rhombus is 60% and its su 
pjement 120* , if any particular angles a 
snamfested m the act of congelation, therefc 
we ought to expect these, agreeable to t 
2d and 3d phenomena 

Whenever any remarkable change in t 
internal constitution of any body takes pla< 
whether by the accession and junction of ne 
particles, or by new arrangements of the 
already existing in it , some modification 
the atmospheres of heat must evidently be i 
quired, though it may be difficult to estim c 
the quantity, and sometimes even the kind 
change so produced, as m the present ca< 
So far therefore the theory proposed agrc 
with the 4th phenomenon 

In order to explain the other phenomena, 
will be requisite to consider more particula 1 
the mode by which bodies are expanded 
heat Is the expansion occasioned simply 
the enlargement of the individual atmosphei 
of the component particles ? This is the ca 
with elastic fluids, and perhaps with soh< 
but certainly not with liquids How is it p< 
sible that water should be expanded a portu 



SODIUM. WL 

solution in sulphuric acid 9 At ordinary temperature monockme 
crystals of the monohydrate are deposited at 50 C tecJimc crystals 
of the anhydrous substance * 

Sodium hydrogen sulphate is a white salt, of density ^ 4S5 at 13 C 
Its heat of formation from the elements is given by Thomsen 3 as 267 4 
Cal , and by Berthelot 4 as 269 1 Cal , from sulphuric acid and sodium 
hydroxide it is 14* 75 Cal The heat of solution is given by Thomsen 5 
as 1 19 Cal , but by Berthelot as 8 Cal 

Other investigations concern the Molecular volume e , and such 
properties of the solution as viscosity, 7 density, 8 and electric con- 
ductivity 9 

Various sulphates of sodium and hydrogen have been prepared 
With absolute sulphuric acid sodium sulphate reacts, forming a complex 
crystalline derivative 10 melting at 40 C , and having the formula 
Na 2 S0 4 ,8H 2 SO 4 d'Ans 11 has prepared another example with the 
composition Na 2 SO 4 ,NaHSO 4 Kendall and Landon 12 have described 
2Na 2 SO 4 ,9H 2 SO 4 , an unstable substance at its melting-point, 60 C (by 
extrapolation) , Na 2 S0 4 ,2H 2 SO 4 , unstable at its melting-point , and 
Na 2 SO 4 ,H 2 S0 4 , melting at 186 C Other compounds of similar type 
have been prepared 13 

Sodium monopersulphate, Na 2 S0 6 This salt is produced by the 
interaction of barium perhydroxide and sodium hydrogen sulphate u 

Ba(OH) 4 +2NaHSO 4 =Na 2 S0 5 +BaSO 4 +3H 2 

Sodium pyrosulphate, Na 2 S 2 O 7 The pyrosulphate is produced by 
the action of sulphur dioxide on sodium sulphate, or by heating the 
primary sulphate 

2NaHS0 4 =Na 2 S 2 7 +H 2 O 

On ignition, it yields the normal sulphate and sulphur trioxide 

Sodium persulphate, Na 2 S 2 8 The persulphate is formed in solution 
by the electrolysis of a concentrated aqueous solution of sodium sulphate 
at low temperature and high current-density The solid persulphate 
can be obtained by double decomposition of ammonium persulphate 
and sodium carbonate either in the solid state or in concentrated 
solution, the erystallme salt being isolated from the solution either by 
addition of alcohol or by concentration at reduced pressuie 15 When 
dry arid protected trom sunlight, it keeps almost unchanged for years lb 

1 Mangn u Contpt tend , Iba7 45 OoO 

Spimg Bull Auid toy Bd</ 1904,290 

J JLhoiiibtn, Thtnnoclic.mn>tht Unte)suchu?iyut 1 tipt>ic Ibb2-lbb3 3 233 
4 Bcithclot Ann Chim PJiy>> 1875 [5] 4 100 

Ihomscn Thinnothetutbtty (Longmans, lOOb) 49 i2b 
" bpiing Bull Atari loy Bdy 1904, 290 

7 Mooie Physical Rev 1890 3 321 

* Maugiiac Anualui buppl 1872 8 335 

8 13 nth JciktJi phytilal Chun Ib92 9 Ibo 

10 Boigius Zeihch phybilal Chun 1910 72 33b 

11 dAns Bet 1906 39 1534 

1 Kendall and I andon J Amct Chem /Se 1920 42 2131 

13 Compaic d Ans, Zeitt,ch anory Chun 1913 80, 295 loutc J Ind Etuj Chem 
1919 u, 029 

14 Merck Get man Patent 1909 No 213457 oompaio Willstattti and Hauenstem, 
Bu 1909 42 1839 

15 Lowenherz German Patent* Nos 77340 and 81404 

16 Elbs and Neher, Chem Zeit 1921,45 1113 



140 OH CONGELATION. 

in moment, and a portion of ice formed ; heat 
is then given out which retards the subsequent 
formation, till at last the whok is congealed. 
This is the ordinary process of congelation. 
But if the mass of water cooled is kept in a 
state of perfect tranquillity, the gradual ap- 
proach to the rhomboidal form can be earned 
much farther , the expansion goes on accord- 
ing to the usual manner, and tht slight friction 
or adhesion of the particles is sufficient to 
counteract the balance of energies in favour of 
the new formation, till some accidental tremor 
contributes to adjust the equilibrium A 
similar operation is performed when we lay a 
piece of iron on a table, and hold a magnet 
gradually nearer and nearer , the proximity of 
the approach, without contact, is much assisted 
by guarding against any tremulous motion of 
the table Hence the rest of the phenomena 
are accounted for 



SODIUM. 



123 



For the density of the anhydrous salt Gerlaoh* gives I 667 at mean 
temperature compared with water at 4 C , for the pe&tahydrate iCopp 2 
gives 1 786, Dewar 3 1 729 at 17 C and 1 76S5 at the temperature of 
liquid air For the specific heat of the anhydrous salt between 25 
and 100 C Pape 4 gives 0221, for the p< nl i1i\<Tr.u< between 11 
and 44 C Trentmagah 6 04447, and for th< liquid Ixl ween 13 and 
98 C , 569 The molecular heat 6 of the anhydrous salt is 34 91, and 
of the pentahydrate 86 22 Berthelot gives the heat of formation of 
the anhydrous salt from its elements as 256 3 Cal 7 or 262 6 Cal , 8 and 
Thomsen 9 that of the pentahydrate as 265 07 Cal Berthelot found for 
the heat of solution of the anhydrous salt 1 7 Cal at 15 C , his value 
for that of the pentahydrate at 11 C is 10 8 Cal , and Thomsen's 10 
11 37 Cal , so that the heat of hydration of the anhydrous salt to 
pentahydrate is about 13 Cal 

Nine hydrates, including thirteen crystalline forms, have been 
described n The pentahydrate melts at 48 45 C , and the dihydrate 12 
at 50 3 C Each exists in two isomenc forms According to Muller, 13 
the unstable form of the pentahydrate crystallizes at 20 C and 
melts at 33 C , the stable modification crystallizes at 40 C and 
melts at 48 C The transition point of the pentahydrate to the di- 
hydrate is 48 17 C , and of the dihydrate to the anhydrous salt 68 5 C 
The solubility of the pentahydrate, the dihydrate, and the anhydrous 
salt, expressed in grams of Na 2 S 2 3 per 100 grams of solution, are given 
in the table u 



Temperature C 





5 


10 


15 


20 


25 


30 


35 


40 


45 


Pentahydrate 


334 


353 


374 


391 


41 2 


432 


452 


477 


508 


553 


Dihydrate 


527 


534 


539 


546 


552 


560 


57 1 


582 


594 


607 


Tempeiature, C 


40 


45 


50 


55 


60 


65 


70 


75 


80 




Dihydrate 


594 


607 


623 


639 


657 


680 










Anhydrous salt 


674 


67 6 


678 


682 


685 


688 


691 


694 


699 





In contact with the solid the saturated solution boils at 126 C , and 
contains 348 gi ims of the anhydrous salt in 100 giams of water lo 

Concentrated solutions of sodium thiosulphate aic modciatcly 
stable, but in dilute solution atmospheric caibon dioxide tends to 
liberate the unstable thiosulphunc acid, a substance readily changed 

1 Cuilddi Chun Imluttr 1880 9 241 
Kopp -lunalui 1855 93 129 

3 Dewai Chem News 1902 85 277 

4 Papc Pogg Annalen 1865 125 513 

5 Irentmaglia Sitzungsber K Akad Wiss Wien 187b, [2] 72 (>b9 

6 bchottky, PJiysilal Zeitsch 1909, IO, 634 

7 JJeithelot Thermochimie Pans, 1897 I 207 

Beithelot, Ann Chwt Phys 1879 [5] 17 468 
9 Ihomsen, Thermochemi6try (Longmans 1908) 328 

10 Thomsen ibid 49 

11 Young Mitchell andBuike,J 4 we? Chem Soc 1904 26 1389 1413 1906 28,315 

I Gomez Compt ttnd 1909 149, 77 

1J Mullei Zeitsch physilal Gliem 1914 86 177 

II Young Mitchell and Buike loc cit Tayloi, Proc Roy tioc Edm 1897-98 
22, 249 

15 Gerlach, Zeitsch anal Chem , 1887, 26 413 



142 ON THB COKSTtfffTlOH OF BO DUBS, 

properly called in that view, attraction qf 
cohesion , but as it collects them from a dis- 
persed state (as from steam into water) it 1$ 
called, attraction qf aggregation^ or more 
simply* affinity. Whatever names it may go 
by, they still signify one and the same power. 
It is not my design to call in question this con* 
citron, which appears completely satisfactory > 
but to shew that we have hitherto made no 
use of it, and that the consequence of the 
neglect, has been a very obscure view of 
chemical agency, which is daily growing more 
so ID proportion to the new lights attempted 
to be thrown upon it 

The opinions I more particularly allude to, 
are those of Berthollet on the Laws of che- 
mical affinity , such as that chemical agency is 
proportional to the mass, and that in all che- 
mical unions, there exist insensible gradations 
in the proportions of the constituent principles 
The mconsistence of these opinions, both 
with reason and observation, cannot, 1 think, 
fail to strike every one who takes a proper 
view of the phenomena 

Whether the ultimate particles of a body, 
such as water, are all alike, that it, of the 
same figure, weight, &c is a question of some 
importance From what is known, we have 
no reason to apprehend a djycrwty in these 



SODIUM 125 

oxidized directly to sulphate without the intermediate formation of tetra 
thionate, weak alkali havmg a similar, though only j>artial ? effect 

The action of hypochlonte solutions OB ^o<bum thiosulphate is HI 
accordance with the equations 1 



or 

3Na 2 S 2 O 3 +5NaOCl+5H 2 O=2Na 2 SO 4 +Na 2 S 4 O 6 +5Naa+5H 2 O 

In presence of acids or sodium hydrogen carbonate, the reaction accords 
with the equation 

Na 2 S 2 3 +4Cl 2 +5H 2 =2NaHSO 4 +8HCl 

Kurtenacker 2 found that cyanogen bromide and iodide react with 
sodium thiosulphate in neutral solution in accordance with the equation 

3CNBr+5S 2 3 / '+H 2 0=3Br / +2HCN+CNS / +SO/+2S 4 6 " 

In acidic solution the thiosulphate is converted into tetrathionate 

CNBr+2S 2 3 "+H =Br'+HCN+S 4 O 6 " 

The reaction in neutral solution probably involves two stages, the 
solution becoming temporarily alkaline through the formation of sodium 
cyanide, which reacts with the generated tetrathionate in accordance 
with the equation 

Na 2 S 4 6 +3NaCN+H 2 0=NaCNS+Na 2 S0 4 +Na 2 S 2 3 +2HCN 

The thiosulphate produced then reacts with the halogen cyanide 

A mixture of crystallized sodium thiosulphate and ammonium nitrate 
finds application as a freezing-mixture 3 

References are appended to investigation of the refractivity 4 of the 
solid , to properties of solutions such as the transition-points of the 
hydrates, 5 supersaturation, 6 electric conductivity, 7 density, 8 vapour 
pressure, 9 boiling point, 10 molecular depression of the freezing-point n re 
fractivity, 12 solubility in alcohol, 13 and electrolysis 14 , and to the formation 
of mixed thiosulphates of sodium and potassium ind their isomcrism 15 

1 Dienert and Wandenbulcke Compt rend 1919 169 29 

2 Kurtenacker Zeitsch anorg Chem 1921 116 243 compare howe\er Memeke 
ibid 1893 2,157 Dix on and Taylor Trans Chem Soc 1913 103 974 

3 Schubardt German Patent 1911 No 233596 

4 Dufet Bull Soc jranc Mm 1888 II 123 191 

6 Trentmagha Sitzungsbtr K Akad Wis? Wien 1870 [2] 72 009 Richards and 
Churchill Zeitsch phynkal Chem 1899 28 314 Dawson and Jackson T/r/w? CJicw 
Soc 1908 93 344, Guthrio Phil Mag 1878 [ r >] 6 41 

Blumcke Zeitwh phynkdl Chew 1896 20 586 

7 Kustei and Thitl Zettsch ftnorq Client , 1899 21 401 

8 Damien Ann cole Norm 1881 [2] 10 2^\ 

9 Tammann Mem Acarl flt Petfrsboury 1887, [7] 35 No 9 compuo 1 escanr 
Ann Chim Phys 1896 [7] 9 r >37 

10 Gerlach Zeitsch anal Chem 1887 26 413 

11 Richards and Faber Amer Chem J 1899 21 172 compare Fil tor Pharw 
Port 1902 34 769 

1 Bary Compt rend 1892 114 827, compare Miers and Isaac Trans Chem Soc 
1906 89 413 

13 Parmentier Compt rend 1896, 122 135 compare Bruner ibid 1895 121 59 

14 Thatcher, Zeitsch phywkal Chem 1904 47 641 

15 Schwicker Ber 1889, 22, 1730 



OK THE CONSTITUTION OF BODIES. 

actual contact This appears to be satisfae* 
toftly prowd by the observation, that the bulk 
of a body may be diminished by abstracting 
some of its beat * Bat from what has been 
stated in the last section, it should seem that 
enlargement and diminution of bulk depend 
perhaps mom on the arrangement, than on the 
size of the ultimate particles Be this as it 
may, we cannot avoid inferring from the pre~ 
ceding doctrine on heat, and particularly from 
the section on the natural zero of temperature, 
that solid bodies, such as ice, contain a large 
portion, perhaps of the heat which the 
same are found to contain in an clastic state, 
as steam 

We are now to consider how these two 
great antagonist powers of attraction and re- 
pulsion are adjusted, so as to allow of the three 
different states of ilastu ftunl\, liquid*, and 
whd* We shall divide the subject into four 
Sections, namelj, first, on the < (institution of 
pure elastic fluid*. , second, oji flu tt>n\ntutwu 
of mixed clastic fluids , third, on th< 
twn of liquids, and fourth, on the 
of solids 



SODIUM 127 



The tetrathionate is converted by the action of sodium sulphite into 
trithionate and thiosulphate l 



With alkali-metal cyanides the tetrathionate reacts m accordance with 
the equation 2 

Na^Oe+SNaCN+H/) =NaCNS+Na 2 SO 4 +Na 2 S 2 O 3 +2HCN 

At the boiling-point, in presence of excess of cyanide, the thiosulphate 
formed reacts further to produce thiocyanate and sulphite 

Sodium pentathionate, Na 2 S 6 6 This salt has not been obtained 
in the pure state, but is said to be one of the products of the decom- 
position of acid solutions of sodium thiosulphate, the sulphur dioxide 
liberated reacting with the thiosulphate 3 

5Na 2 S/) 3 + 3SO 2 =2Na 2 S 5 O e + SNa^Og 

It is also said to react with sodium sulphite, yielding the trithionate and 
thiosulphate 3 

Na 2 S 5 6 +2Na 2 S0 3 =Na 2 S 3 6 +2Na 2 S2O 3 

Sodium hyposulphite, Na 2 S 2 O 4 The hyposulphite was first pre- 
pared in solution by Schutzenberger 4 by reducing a solution of sodium 
hydrogen sulphite with zinc, but the yield is unsatisfactory Bernthsen 
and Bazlen 5 obtained the pure substance by reducing the primary 
sulphite with zinc dust in presence of sulphurous acid, 



precipitating the zinc and removing the excess of acid by addition of milk 
of lime, the hyposulphite being salted out in the form of dihydrate by 
addition of sodium chloride They recommend increasing the stability 
of the dihydrate by washing with acetone, at first dilute and finally pure, 
and drying in a vacuum Jcllmek 6 athiscs heating the dihydiatc it 
60 C in vacuum, the process transforming it into the stable anhydious 
salt The hyposulphite can also be pi oduc cd under special expcn mental 
conditions 7 by the electrolytic reduction of sodium hydrogen sulphite, 
Jellmek 8 having obtained a 7 to 8 per cent solution by this means 
Prepared by this piocess, it finds application in the reduction of 
indigo to indigo- white 9 

1 Raschig Zeitsch angew Chem 1920 33 260 

Kuitenacker and liitfech 7eitwh anorcj Chew 1921 117 202 compare Gutmann 
er,1906 39 509 Mackenzie and Marshall Tmm Chem hoc 1908 93 172G 

3 Haschig Zeitsch angew Chem 1920 33 260 

4 rend 1869 69 196 1872, 75 879 

5 Be? 1900 33 120 Bazlen Bu 1905 38, 1057 

6 Kail Jellmek Zeitsch anorg Ckem 1911 70 93 

7 Frank Zeitsch ElelttocJiem 1904 10 4 r >0 Chaumat German Patent, 1910 No 
221614 Elbs and Becker, Zeitsch Llektrochem 1904 10 361 Julius Meyer Zcitech 
anorg Chem 1903 34 43 

8 Karl Jellmek and E Jellmek Zeitsch physilcal Chem 1919 93, 325 

9 HoohsterBarbwerko German Patent, 1902 No 139567 



146 OK PTOE EtASTIC FLUIDS 

of elastic fluid is found to expand v.hene\erthe 
pressure is taken off This proves that the re- 
pulsion exceeds the attraction in such case 
The absolute attraction and repulsion of the 
particles of an elastic fluid, we have no means 
of estimating, though we can have little doubt 
but that the cotemporary energy of both is great, 
but the excess of the repulsive energy above 
the attractive can be estimated, and the law of 
increase and diminution be ascertained in many 
cases Thus m steam, the density may be 
taken at TT I T that of water , consequently 
each particle of steam ha;> 12 times the diameter 
that one of water has, and mut press upon 
144 particles of a watery sunacc, bur the 
pressure upon each is equivalent to that of a 
column of water of 34 feet , therefore the ex- 
cess of the elastic force in a particle of steam is 
equal to the weight of a column of particles of 
water, whose height is 34 X 144 48% ieet 
And further, this elastic forct decreases as the 
distance of the par icles increases \\ith re- 
spect to steam and other clistic fluids then, 
the force of cohesion is tntin Iv counteracted 
by that of repulsion, and the onlv force which 
ib efficacious to move the particles is the e\cess 
of the repulsion above the attraction 1 hus, if 
the attraction be as 10 and the repulsion as 
12, the effective repulsive force is at> 2 It 



SODIUM. 120 

sulphate, a reaction apphed by Baden and Bernthsen to the quantitative 

estimation of the salt ^ "*" 

^ 

Na 2 S a O 4 +6l+4H 2 O=2NaHSO 4 +6HI 

The action of selenium and tellurium on sodium hyposidp&ite has 
been investigated by T\< hugi< \ and Cblopin a 

The hyposulphite was employed by Julius Meyer 3 in the prepara- 
tion of metallic colloidal solutions It finds technical application as 
a reducer m the dye-industry When administered intravenously, it 
exerts a toxic effect 4 

Sodium selemdes The monoselemde, Na^e, is formed by the 
action of selenium on a solution of excess of sodium in liquid ammonia, 
and separates out 5 It can also be produced by the interaction of 
selenium and sodium hyposulphite, Na 2 S 2 O 4 6 It melts above 875 C , 
and on exposure to air its solution in water acquires a reddish colour, 
and deposits selenium In solution it is extensively hydrolyzed, and 
under these conditions may be regarded as a mixture of sodium hydrogen 
selemde, NaSeH, and sodium hydroxide Four hydrates are known, 
with 4J, 9, 10, and 16 molecules of water respectively 7 For the heat 
of formation of the anhydrous compound Fabre 8 gives 59 7 Cal , and 
for the heat of solution at 14 C , 18 6 Cal He has also investigated 
the heat of solution of the hydrates 

When excess of selenium reacts with a solution of sodium in liquid 
ammonia, sodium tetraselenide f Na 2 Se 4 , separates 9 By fusion of 
sodium with selenium, Mathewson 10 has isolated between 500 and 
250 C the diselenide Na 2 Se 2 , tnselemde Na 2 Se 3 , tetraselenide Na 2 Se 4 , 
and he&aselenide Na 2 Se 6 They are dark grey substances, unstable 
in air, and readily soluble in water to red solutions 

Sodium selemte, Na 2 Se0 3 The selemte is formed by heating a 
mixture of selemous acid and sodium chloride u At ordinary tempera- 
ture the aqueous solution deposits the pentahydrate, above 60 C the 
anhydrous salt 12 For the heat of formation from its elements in aqueous 
solution Thomsen gives 238 4 Cal 

Berzelms mentions a salt which was either sodium hydrogen selemtt, 
NaHSeO 3 , or pyroselenite, Na 2 Se 2 5 

Sodium selenate, Na 2 Se0 4 The sclenatc is prepared from sodium 
selemte by electrolytic oxidation with platinum electrodes at ordinary 
temperature 13 A by-product analogous to the dithionitc obtained in 
the electrolytic oxidation of sodium sulphite is not formed 14 

1 Bazlen and Bernthsen Ber , 1910 43, 501 
Ischugaev and Chlopm Ber 1914 47 1209 

3 Julius Mtyer Zieitsch anorg Chem 1003, 34, 43 

4 Heyl and Greer Amer J Pharm 1922 94, SO 

5 Hugot Compt rend, 1899 129 2<)9 
fi Pschugaev and Ohlopin loc at 

7 labro Ann Chim Phys 1887 [6] 10 505 Clever and Muthmann Zntwh anorg 
Chem 1895 10 17 

8 labrt Ann Chim Phys 1887 [6] 10 505 

9 Hugot Compt rend 1899 129 299 

10 Mathewson J Amer Chem Soc 1907 29 867 

11 Cameron and McCallan Chem News 1889 59 258 
1 Nilson Bull Soc chim 1874 [2] 21,253 

13 Muller Bet 1903 36 4262 

14 Compare Forster and Friessner Ber 1902 35 2515 

VOL II 9 



148 on *raB Buutric 

the density of die atmospheres of heat most 
fluctuate with the pressure* Thus, suppose a 
measure of air were expanded mto 8 measures , 
ften, because the diameters of the elastic par- 
ticks are as the cube root of the space, the 
distances of the particles would be twice as 
great as before, and the elastic atmospheres 
would occupy nearly 8 times the space they 
did before, with nearly the same quantity of 
heat whence we see that these atmospheres 
must be diminished in density in nearly the 
same ratio as the mass of elastic fluid 

Some elastic fluids, as hydrogen, oxygen, &c 
resist any pressure that has yet been applied 
to them In such then it is evident the re* 
pulsive force of heat is more than a match for 
the affinity of the particles, and the external 
pressure united To what extent this would 
continue we cannot say , but from analogy we 
might apprehend that a still greater pressure 
would succeed in giving the attractive force 
the superiority, when the elastic fluid would 
become a liquid or solid In other elastic 
fluids, as steam, upon the application of com- 
pression to a certain degree, the elasticity ap- 
parently ceases altogether, and the particles 
collect in small drops of liquid, and fall down. 
This phenomenon requires explanation 

From the very abrupt transition of steam 



SODIUM. 131 

Sodium tellurate, 1 Na 2 Te0 4 ,2H 2 The tellurate is prepared m a 
similar manner to the selenate 2 It 13 not readily soluble, and under- 
goes reduction easily to tellurium 8 It is only known in the form of 
dihydrate 

Sodium chromates An account is given m this series, Vo| VII , of 
the modes of preparation and of the properties of sodium chromate and 
dichromate 

Sodium nitride, Na 3 N The nitride is formed by submitting sodium 
to the action of the silent electee discharge in an atmosphere of nitrogen 4 
It is decomposed by water, with energetic evolution of ammonia 
Fischer and Schroter 5 also claim to have prepared it, but they give no 
analyses or formula 

Sodium hydrazoate, NaN 3 The hydrazoate is formed by neutralizing 
hydrazoic acid with sodium hydroxide , 6 by the interaction of sodamide 
and nitrous oxide 7 

|| =NaN<^ || +H 2 



and by decomposing hydrazoyl chloride with sodium hydroxide B 
N 3 Cl+2NaOH=NaN 3 +NaOCl+H 2 O 

Sodium hydrazoate forms colourless crystals, which melt without 
decomposition, but explode at a temperature higher than the melting- 
point At 10 C 100 grams of water dissolve 40 16 grams, at 17 C 
41 7 grams 

Sodamide, NaNH 2 Sodamide is formed by the action of liquid 
ammonia on the metal, 9 or by passing dry ammonia over fused sodium 10 
or one of its alloys 11 An apparatus for its preparation has been described 
by Wohler and Stang-Lund 12 

Sodamide is a white substance According to Wohler and Stang 
Lund, 12 it melts at 210 C , and not between 149 and 155 C , as 
stated by Titheiley 13 , but Me Gee 14 found that it melts sharply at 
208 C He was unable to prepare the blue solutions of sodium in the 
amide described by Titherley, 15 and found no solvent action on glass 
below 240 C Contact of the amide with glass for several days at 270 

1 On sodium tellunte compare Lenher and Wolesensky, / Atner Ghem Soc 1913, 
35, 718 

2 Funk Bei 1900 33 3696 

3 Mullei Ber 1903 36 4262 

4 7ehnder Wied Annalen, 1894 52 56 

5 Fischer and Schroter Ber , 1910 43 1465 

Dennis and Benedict Zeitsch anorg Chem 1898 17 19 

7 Wishoenus Ber 1892, 25 2084 Cuitms Bet 1890 23 3023 1891 24 3341 
Curtms and Rissom J praLt Chem 1898 [2] 58 278 

8 Raschig Ber 1908 41 4194 

9 Compaie Joanms Compt rend 1887 109 900 1891 112 392 1892 115 820 
Ann Chim Phys 1906 [8] 7 5 Ruff and Gusel Ber 1906 39,828 

10 Gay Lussac and Thenard, Recherches Phybico Chinnques, Tans 1811 I 354 
Titherley Trans Chem Soc , 1894 65 504 delorcrand Compt lend 1895 121,66 

11 Gold und bilber Scheideanstalt vormals Rbssler German Patent 1901 No 117623 

12 Wohler and Stang Lund Zeitsch Elektrochem 1918 24 261 

13 Titherley Trans Chem Soc 1894 65 504 

14 McGee J Amer Chem Soc 1921 43 586 

15 Titherley loc cit 



OH MIXED StASTIC 

The constitution of a liquid, as water, must 
then be conceived to be that of an aggregate of 
particles, exercising m a most powerful manner 
the forces of attraction and repulsion, but 
aearfy in an equal degree* Of this more in 
the sequel 



SECTION 3. 

ON THE CONSTITUTION OF MIXED 
ELASTIC FLUIDS 



When two or more elastic fluids, whose 
particles do not unite chemically upon mixture, 
are brought together, one measure of each, 
the) occupy the space of two measures, but 
become uniformly diffused through cich other, 
and remain so, whatever may be their specific 
gravities The fact admits ot no doubt , but 
explanations have been given in \anous ways, 
and none of them completely satisfactory As 
the subject is one of primary importance in 
forming a system of chcmic.il principles, we 
must enter somewhat more fully into the 
discussion 

Dr Priestley was one of the earliest to notice 
the fact it naturally struck him with surprise, 



SODIUM. 133 

reduction of the nitrate * , the action of nitrous fumes containing excess 
of nitnc oxide on a solution of sodium hydroxide or carbonate 2 , and the 
action of oxygen on ammonia in presence of platinized asbestos as 
catalyst, the ammonium nitnte produced being transformed by treat- 
ment with sodium hydroxide, and the evolved ammonia being available 
for further oxidation 3 

Sodium nitnte is a white, crystalline salt. Its meltmg-pomt is 
given by Divers 2 as 213 C , but by Matignon and Marchal 4 as 276 9 C 
(corr ), and by Bruni and Meneghini 5 as 284 C At 15 C 100 grams 
of water dissolve 83 3 grams The heat of solution is 3 52 Cal , and 
the heat of formation in solution from the elements is 88 52 Cal 4 

In aqueous solution at 100 C and between 50 and 55 atmospheres 
of pressure, sodium nitnte is not oxidized by prolonged contact with 
oxygen, even in presence of a catalyst 4 When heated in an atmosphere 
of oxygen for nine hours at 175 atmospheres of pressure, the temperature 
being gradually raised from 395 to 530 C , the solid is almost com- 
pletely oxidized to sodium nitrate, but the reaction is too slow for 
practical application 6 

2[NaN0 2 ]+(0 2 )=2[NaN0 3 J+45 Cal 

When heated, sodium nitrite decomposes in accordance with the 
equation 7 

3NaNO 2 =Na 2 O +NaN0 3 + 2NO 

Heating in an atmosphere of nitrogen peroxide yields nitric oxide and 
sodium nitrate 7 

NaN0 2 +N0 2 =NO+NaN0 3 

At 60 C in an atmosphere of carbon dioxide free from air, a 5 per 
cent solution of sodium nitrite is decomposed by metallic copper, with 
evolution of nitrous fumes, but there is not sufficient evidence to enable 
the course of the reaction to be indicated by means of an equation 8 

When an anolyte of sodium nitrite dissolved in twice its weight of 
water is electrolyzed with a silver anode, a complex salt of the formula 
NaAg(NO 2 ) 2 is formed at the anode On evaporation of the solution 
over sulphuric acid in vacuo, it separates in bright yellow ciystals 9 

The nitrite finds extensive application in the manufacture of certain 
synthetic dycstuffs 

References are appended to the solubility in alcohol, 10 and such 
properties of the aqueous solution as density, 11 vapoui piessure, 12 and 
electric conductivity 13 

1 Roister, hlektrochenne wassnger Losunqen Ltiptsic 1905 323 

2 Divcis Tians Ghem Soc 1899 75 85 87 95 

3 Warren Chem Newt>, 1891 63 290 

4 Matignon and Marohal Compt ?cw/,1920 170 232 
Brum and Meneghini Zeifoch atiorg Cheni 1909 64, 193 

6 Matignon and Monnct Compt tend 1920 170 180 

7 Oswald, Ann Chim P%s 1914 [9] i 32 

8 Peters Zeitoch anoiy Ghent 1919 107 313 

9 Jeffery Tians luuadayhoc 1920 15 16 

10 Lobry de Bruyn JRcc ttav chit 1892 n 156 

11 Boguski Bull Acad #ct Cracow 1898 123 

1 Tammann Mem Acad &t Petertbourg 1887 [7] 35 No 9 

13 Schumann Ber 1900 33 532 Roczkowsky and Nicinentowsky Zeitsch physikal 
Ghem 1897 22 147 , compare Holborn, Landolt, Bornstem, and Mey&hoffers Tabellen 
3rd ed, Berlin 1905,749 



152 WT MIXES ItASTIC FUTIDS. 

probable that the notion of water being dis* 
solved in air, led to that of air being dissolved 
in air Philosophers found that water gra* 
dually disappeared or evaporated m air, and 
increased its elasticity, but steam at a low 
temperature was known to be unable to oveiw 
come the resistance of the air, therefore the 
agency of affinity was necessary to account for 
the effect In the permanently elastic fluids 
indeed, this agency did not seem to be so much 
wanted, as they are all able to support them- 
selves, but the diffusion through each other 
was a circumstance which did not admit of an 
easy solution any other way In regard to the 
solution of water in air, it was natural to sup- 
pose, nay, one might almost have been satisfied 
without the aid of experiment, that the differ- 
ent gases would have had different affinities for 
\vater, and that the quantities of water dis- 
solved in like circumstances, would have 
varied according to the nature of the gas 
Saussure found however that there was no 
difference in this respect in the solvent powers 
of carbonic acid, hydrogen gas, and common 
air It might be expected that at least the 
density of the gas would have some influence 
upon its solvent powers, that air of halt density 
would take half the water, or the quantity of 
water would dimmish in some proportion to 



SODIUM. 13$ 

Schuller 1 found 02650, Regnatilt 2 for the previously fused salt 
02782, and Person 3 for the liquid between 320 and 430 C 41 
The latent heat of fusion for 1 gram-molecule at 310 5 C is given by 
Person 3 as 5 5 Cal The heat of formation from the elements is stated by 
Thomsen 4 to be 111 25 Cal , and by Berthelot 5 to be 110 7 Cal , that 
from nitric acid and sodium hydroxide 1$ given by Thomsen * as 18 08 
Cal , and by Berthelot as 13 5 Cal For the heat of sohjti&n Thomsen 
gives 50 Cal, and Berthelot 8 between 10 and 15 C 47 Cal 
The heptahydrate 9 melts at 15 7 C 

The table summarizes the results obtained by the Earl of Berkeley xo 
in his work on the solubility of sodium nitrate 



Temperature, 
C 


Grams of NaN0 8 in 
100 grams of Water 


Temperature, 
C 


Grams of NaN0 8 in 
100 grams of Water 





73 


60 


1246 


10 


805 


70 


136 


20 


88 


80 


148 


30 


962 


90 


161 


40 


1049 


100 


1755 


50 


114 


119 


2088 



Gerlach u gives the boihng-pomt of the saturated solution in contact 
with the solid as 120 C , and its strength as 222 grams per 100 grams of 
water , the Earl of Berkeley and Applebey's 12 value for the boiling point 
is 120 20 C at 760 mm 

In the fused state sodium nitrate is dissociated to the extent of 61 7 
per cent > and its mean molecular refraction between 320 and 440 C 
is 11 54 13 

The molecular electric conductivity of sodium nitrate between 
321 5 and 487 3 C is given by the formula 14 

^=41 56+0 205(2300) 

Sodium nitrate is a very deliquescent substance, 15 and is therefore 
unsuited for the manufacture of explosives It is employed in agri 
culture as a fertilizer, and by double decomposition with potassium 
chloride yields potassium nitrate Large quantities are reduced to 

1 Schuller, Pogg Annalen 1869 136 70 235 

2 Regnault, ibid 1841 53 60 243 

3 Person Ann Chim Phys , 1847, [3] 21 295 
Thomsen, Thermochemistry (Longmans 1908) 324, 325 
Berthelot Ann Chi?n Phys 1873, [4] 30 440 
Thomsen Thermochemistry (Longmans 1908) 115 
Thomsen,,/ pralt Chem 1878 [2] 17, 175 
Berthelot Ann Ohim Phys , 1875, [5] 4, 521 

Ditte Compt rend 1875 80 1164 
Earl of Berkeley Phil Trans , 1904, [A] 203 209 
Geilach Zeitech anal Chem 1887, 26 413 
1 Earl of Berkeley and Applebey Proc Roy Soc , 1911 [A], 85, 489 

13 G Meyer and Heck, Zeitsch Elektrochem , 1922, 28 21 

14 Jaeger and Kapma Zeitsch anorg Chem, 1920, 113 27 
16 Compare Kortwnght, J Physical Chem 1899 3 328 



14 OH MIXED BLA9TIC FLCTID& 

experiments upon which a series of essays were 
founded, which weie read before the Literary 
and Philosophical Society of Manchester, and 
published in the 5th Vol of their memoirs, 
1802 

The distinguishing feature of the new 
theory was, that the parti' lea of one gas are 
not elastic or repulsive m regard to the par- 
ticles of another gas, but only to the particles 
of their own kind Consequently when a 
vessel contains a mixture of two such elastic 
fluids, each acts independently upon the vessel, 
with Us proper elasticity, just as if the other 
were absent, whilst no mutual action between 
the fluids themselves is observed This posi- 
tion most effectually provided for the existence 
of vapour of any temperature in the atmos- 
phere, because it could have nothing but its 
own weight to support , and it was perfectly 
obvious why neither more nor less vapour could 
exist m air of extreme moisture, than in a 
vacuum of the same temperature So far then 
the great object of the theory was att uncd 
The law of the condensation of vapour in the 
atmosphere by cold, was evidently the same on 
this scheme, as that of the condensation of 
pure steam, and experience was found to con- 
firm the conclusion at all temperatures I he 
only thing now wanting to completely establish 



SODIUM 137 

At low temperatures ammonia reacts with sodium and red phosphorus 
to form a reddish-brown, amorphous mass, considered by Hugot 1 to be 
sodium phosphide With excess of sodium, yellow erystalfc of the formula 
Na 3 P 2 H 3 are formed They react with water and acads, evolving 
phosphme 

Na 3 P 2 H 3 +3H 2 =3NaOH+2PM 3 

Sodium dihydrophosphide, NaPH 2 , is a white substance^ formed 
by treating a solution of sodium in, hquid ammonia with phospnme, and 
evaporating the ammonia 2 Tnsoditm phosphide, Na 3 P, is produced 
simultaneously Tfye mixture reacts with water, evolving phosphme 

Sodium hypophosphite, NaHgPOjj The hypophosphite is formed 
by the interaction of sodium hydroxide and phosphorus 

P 4 +3NaOH+3H 2 0=3NaH2PO 2 +PH 3 

It can also be obtained by decomposing the calcium or barium salt by 
the action of sodium carbonate in alcoholic solution 

Sodium hypophosphite is a powerful reducer On heating it evolved 
phosphine, the reaction being often so violent as to cause explosion 3 

5NaH 2 PO 2 =Na 4 P 2 7 +NaP0 8 +2PH 3 +2H 2 

At 21 5 C the heat of formation from sodium hydroxide and the 
acid is 15 16 Cal , 4 and that from the elements in solution is 198 4 Cal 5 
The electric conductivity has been studied by Arrhemus 6 

Sodium phosphites Disodium hydrogen phosphite, Na 2 HPO 3 ,5H 2 0, 
is obtained by concentration of a solution of phosphorous acid neutralized 
with sodium carbonate, and over sulphuric acid changes to the anhydrous 
salt The pentahydrate is very deliquescent The anhydrous salt 
melts at 53 C , and above this temperature is oxidized to sodium 
phosphate, with evolution of phosphme 7 The heat of formation from 
the elements is 285 1 Cal , 8 and from the acid and sodium hydroxide 
in solution 28 45 Cal 9 The heat of hydration of the anhydride to the 
pentahydrate is 13 7 Cal 

Sodium dihydrogen phosphite, NaH 2 PO 3 ,2|H 2 O, crystalli/es when a 
solution of cquimolccular proportions of phosphoious acid and sodium 
hydroxide is cooled to 23 C The heat of formation of the anhydious 
salt from the elements is 333 b Cal , 8 and fiom the acid and sodium 
hydroxide in solution 1-1 83 Cal 10 The heat of hydrition of the hydiate 
is 6 05 Cal 

When anhydrous sodium dihydiogen phosphite is hcited it 1GO C 
it is converted into duodium dihydtogen pytophovphite, Na, 2 II 2 P 2 O 5 It 
foims microscopic crystals, rcconveited by heating in solution into the 
paient substance The heat of foimation fiom the elements is 509 Cal n 

1 Hu^ot Oompt tend 1895 121 200 189b 126, 1719 

Juanms ibid 189-i 119 557 

3 ilarnmclsberk Sitzmxibbtr K Alad H JSA Berlin 1872 412 
1 Compare Airhonms PciUch physikul Chun ls ( )2 9 3 J9 

1 horn sen Thcrmochcmttche Untubiichunyen 1 t ipsu lbb2-18S3, I, 421 
fa An hermits loc cit 
1 Amat Compt rend 1890 no 191 

8 Thomson Thermochani^che, U nlen>iichunqen \ upsic 1 882-1 bb3 I, 9b 

9 Thomson, Thermochemistry (Longmans, 1908) 96 

10 Thomson ibid , 98 

11 Amat loc cit 



156 ON MIKED ELASTIC FLUIDS 

consequently reprobated. This must have 
have arisen partly at lca$t from my being too 
concise, and not sufficiently clear m its ex- 
position 

Dn Thomson was the first, as far as I know, 
who publicly animadverted upon the theory, 
this gentleman, so well known for his excellent 
System of Chemistry, observed in the first 
edition of that work, that the theory would 
not account for the equal distribution of gases ; 
but that, granting the supposition of one gas 
neither attracting nor repelling another, the two 
must still arrange themselves according to their 
specific gravity But the most general objec- 
tion to it was quite of a different kind , it was 
admitted, that the theory was adapted so as to 
obtain themost uniform and permanent diffusion 
of gases, but it was urged, that as one gas 
was as a vacuum to another, a measure of any 
gas being put to a measure of another, the 
two measures ought to occupy the space of 
one measure only Finding that my views on 
the subject were thus misapprehended, I 
wrote an illustration of the theory, which was 
published in the 3d Vol of Nicholson's Jour- 
nal, for November, 1802 In that paper I 
endeavoured to point out the conditions of 
mixed gases more at large, according to my 
hypothesis , and particularly touched upon the 



SODIUM. 150 

crystalline salt, its solubility * at 10 C per 100 grams of water being 
3 9 grams, and at 30 C 24 1 grams 

Solubility ofDwodvum Hydrogen Orihopho&ph&fe (Shiomi) 2 

Temperature, C 10 2d 25 15 40 29 60 23 99 77 

Grams Na 2 HPO 4 m 100 g H 2 O 8*55 12 02 54 88 83 00 102 15 

There are three breaks in the curve at 36 45 C , corresponding with 
the transition from dodecahydrate to heptahydrate , at 48 C (probably 
heptahydrate to dihydrate) , and at 95 2 C (probably dihydrate to 
anhydrous salt) Later work 3 has indicated the dodecahydrate to 
exist in two forms, a and /?, their transition-temperature being 29 6 C 
The transition-temperature of the a-hydrate to the heptahydrate was 
found to be 35 C The solubilities of the two dodecahydrates were 
also determined 

For the density of the dodecahydrate Clarke 4 gives 1 535, and at the 
temperature of liquid air Dewar 5 gives the value 1 545 For the specific 
heat of the crystalline salt between 20 and 2 C Person 6 found 
454, and for the fused salt between 44 and 97 C 758 , for the 
solid dodecahydrate Nernst and Lmdemann 7 give 3723, and for the 
heptahydrate 3280 Thomsen 8 gives 50 04 Cal as the heat of forma- 
tion of the dihydrate from sodium hydroxide and phosphoric acid 9 
The latent heat of fusion of the dodecahydrate at 36 1 C is given by 
Person 10 as 23 9 Cal 

For the transition-points of the dodecahydrate to the heptahydrate 
and of the heptahydrate to the dihydrate d'Ans and Schremer 11 give 

Na 2 HP0 4 ,12H 2 O(35 4 C ) *Na 2 HP0 4 ,7H 2 O(48 35 C ) > 

*Na 2 HP0 4 ,2H 2 

At a pressure of 1 atm Biltz 12 gives the transition-points on the 
absolute scale as 

Na 2 HP0 4 ,12H 2 0(317) >Na 2 HP0 4 ,7H 2 0(319)-^ 

^Na 2 HPO 4 , 2H 2 O(346) --^Na 2 HPO 4 

The transition-point of the dodecahydrate into the heptahydrate is 
given by Person 13 as 36 4 C , Baur 14 36 6 C , and Tilden lj 35 C , and 
the transition-point into the anhydrous salt by Muller lb as 43 5 C 



1 Mulder, Bydragen, etc , Rotterdam, 1864, 100 , d Ans and bchremer, JeitsUi phy&iLal 
Chem , 1910, 75, 95 

2 Shiomi Mem Coll Sci Eng Kyoto 1909 i, 406 

3 Hammick Goadby and Booth Trans Chem Soc 1920, 117 1589 

4 Clarke Constants of Nature, 2nd ed Washington 1888 1,114 

5 Dewar, Chem News, 1902, 85, 277 

Person, Pogg Annalen 1847, 70, 300 

7 Nernst and Lmdemann, Sitzungsber K Akad Wiss Berlin, 1910, 247 

8 Thomsen, Thermochemische Untersuchungen Leipsic, 1882-1883, 3, 233 
Compare Berthelot and Lougumme Ann Chim Phys 1876 [5] 9 28 

10 Person ibid , 1849 [3] 27 252 259 

11 d Ana and Schremer Zeitsch physikal Chem , 1910, 75, 95 
1 Biltz ibid 1909, 67 561 

13 Person loc cit 

14 Baur Zeit&ch physikal Chem 1895 18 180 

15 Tilden, Trans Chem Soc , 1884 45, 268 
18 Muller J Chim phys , 1909, 7, 534 



}58 OH MIXED ELASTIC FLUIDS 

atto$phere, in which he has entered largdy 
into a discussion of the new theory. This cele- 
brated chemist, upon comparing the results of 
experiments made by De Luc, Satiasure, Yofta, 
Lavoisier, Watt, &c. together with those of 
Gay Lussac, and his own, gives his full assent 
to the fact, that vapours of every kind increase 
the elasticity of each species of gas alike, and 
just as much as the force of the said vapours 
in vacuo , and not only so, but that the specific 
gravity of vapour in air and vapour in vacuo 
is mall cases the same (VoJ I Sect 4*} Con** 
sequently he adopts the theorem for finding 
the quantity of vapour which a given volume 
of air can dissolve, which I have laid down, 
namely, 



s = 

where p represents the pressure upon a given 
volume (l) of drv air, expressed in inches of 
mercury,/" the force of the vapour in vacuo 
at tlie temperature, in inches of mercury, and 
^= the space which the mixture of air and 
vapour occupies under the given pressure, p f 
after saturation So far therefore we perfectly 
agree but he objects to the theory by which 
I attempt to explain these phenomena, and 
substitutes another of his own 

The first objection I shall notice is one that 




SODIUM 



The product is a white substance, its melting-point being given by 
Carnelley l as 8d8* C and by Le Ghateber a as 957 C and also 3 as 970 C 
For the density Schroder* gives 2 $4, aad Mohr 5 2 85 Betw^aa 
17 and 98 C Regnault 6 found the specific heat to be 228a* The 
heat of solution is given, by Thomson 7 as 11 85 Cal 

Sodium pyrophosphate caystafli^es from water $$ the naoiioeliste 
decahydrate Its density is given by Playfair end Joule 8 as 1 886, 
Mohr 9 1 773, and Dufet 10 1 824, and its heat of solution by Thomsen 11 
as 11 67 Cal At 20 C 100 grams of water dissolve 6 2 grams* a&d 
at 80 C 30 grams, 12 yielding a solution of faint alkaline reaction 

Other investigations concern the refractivity u , and properties of the 
solution such as density, 14 vapour-pressure, 15 and electnc conductivity 1 

Disodium dihydrogen pyrophosphate, Na 2 H 2 P 2 O 7 This substance 
is formed by heating sodium dihydrogen phosphate at about 200 C 

2NaH 2 P0 4 =Na 2 H 2 P 2 7 +H 2 

Above 300 C it is converted into sodium metaphosphate 

In addition to the anhydrous salt, a tetrahydrate, 17 and also a 
hexahydrate 18 of density 19 1 848, are known The aqueous solution has 
an acidic reaction, and reacts with sodium hydroxide to form the normal 
pyrophosphate 

Sodium metaphosphate, NaPO 3 The metaphosphate is prepared by 
the interaction of sodium nitrate and phosphoric acid at 330 C 20 It is 
a white, vitreous mass, almost insoluble in water, and melting 21 at 
617 2 C It is sometimes called " Maddrell's salt," after its dis 
coverer 22 The semihydrate, NaP0 3 ,JH 2 O, is formed by heating sodium 
ammonium hydrogen phosphate at 160 to 170 C , and subsequently 
raising the temperature to 320 C 23 Tammann 24 has proved the existence 

1 Carnelley, Trans Chem Soc 1878 33 273 

2 Le Chateher, Bull Soc chim 1887, [2] 47 300 

3 Le Chateher, Oompt rend 1894 118 350 

4 Schroder Dichtigkeitsmessungen Heidelberg 1873 

6 Compare Clarke, Constants of Nature 2nd ed , Washington 1888 i lib 

6 Regnault Pogg Annalen, 1841 53 60 243 

7 Thomsen J prakt Chem 1878 [2] 17 175, Thermochemistry (Longmans 1908) 49 

8 Playf air and Joule Mem Chem Soc 1843-1845 2 401 

9 Compaie Clarke loc cit 

10 Dufet Bull Soc franc. Mm 1887, 10 77 

11 Thomsen loc cit 

12 Poggiale J Pharm Chim 1863 [3] 44 273 

13 Dufet loc cit 

14 Fouquc Ann Obs(tvat Pans 1868 9 172 

18 Tammann Mem Acad St Pete^bounj 1887 [7] 35 No 11/^7 \nnnleti 18S> 
24 530 

16 Walden Zeitsch yhynlal Chem ,1887 I 529 

17 Rammelsbcrg Gcsamt Abhandl 1888 127 

18 Biyer / pralt Chem 18G9 106 501 

19 Dufet loc cit 

von Knorre Zeitsch anorg Chem 1900 24 378 

1 Oarnelley loc cit 

Maddrell Phil Mag 1847 [3] 30 322 

23 T angheld Oppmann and E Meyer Ber 1912 45 3753 

24 Tammann J pralt Chem 1892 [2] 45 421 Zeit^ch physikal Chem 1890 
6 124 compare Warschauer Zeitsch anorg Chem 1903 36 188 Mtrtminn Pogg 
Annalen 1849 78 361 Fleitmann and H Annalcn 1848 65 307 Jawem 
andThillot Ber 1889 22 655 Clarke Constants oj hatmc 2nd ed , Washington 1888 I 
118 Tammann Mem Acad St Petersbourg 1887, [7] 35 No 9 Wiesler, Zeitsch 
anorg Chem 1901 28 182 Walden, Zeitsch physikal Chem 1887 i, 529 



160 OK MIXED ELASTIC 

without, and an enlargement of the volume of 
air is unavoidable, in order to restore the 
equilibrium Again, in the open air suppose 
there were no aqueous atmosphere around the 
earth, only an azotic one = 23 inches of mer* 
cuiy, and an oxygenous one = 6 inches The 
air being thus perfectly dry, evaporation would 
commence with great speed The vapour 
first formed being constantly urged to ascend 
by that below, and as constantly resisted by tho 
air, must, in the first instance, dilate the other 
two atmospheres , (for, the ascending steam 
adds its force to the upward elasticity of the 
two gases, and in part alleviates their pressure, 
the necessary consequence of which is dilata- 
tion ) At last when all the vapour has as- 
cended, that the temperature will admit of, 
the aqueous atmosphere attains an equilibrium , 
it no longer presses upon the other two, but 
upon the earth , the others return to their 
original density and pressure thioughout In 
this case it is true, there would not be any 
augmentation of \olumc when aqueous vapour 
was combined with the air, humidity would 
increase the weight of the congregated atmo- 
sphere s,but diminish their specific gravity under 
a given pressure One would have thought that 
thia solution of the phenomenon upon my 
1 upothcsii 3 was too obvious to escape the notice 



SODIUM 143 

vacuum, or in a current of hydrogen at 220 C , it evolves acetylene, 
leaving sodium carbide The carbide is very reactive, readily under- 
going decomposition with deposition of carbon, and decomposing water 
with evolution of acetylene * 

Sodium carbonate, Na 2 CO s The carboBate is present in the ashes 
of sea-plants, its principal source pnor to the Preach Revolution, when 
Le Blanc devised a method for its production It is also found m the 
form of solid deposits, 2 and in solution in many natural waters Po^zi- 
Escot 3 believes the Peru deposits to have originated in the reduction to 
sodium sulphide, by means of plants and algae, of sodium sulphate 
dissolved from the soil, the sulphide formed being converted into 
sodium carbonate or sodium hydrogen carbonate by the action of cafbon 
dioxide from the air, or from the decomposition of vegetable matter 

Sodium carbonate is manufactured from sodium chloride by three 
processes Le Blanc's process, Solvay's ammonia-soda process, and the 
electrolytic process 4 

Le Blanc's Process This process involves three stages the con- 
version of sodium chloride into sodium sulphate, or " salt-cake process " , 
the reduction of the sulphate to sulphide by means of carbon, and the 
conversion of the sulphide into sodium carbonate by the action of calcium 
carbonate, or " black-ash process " , and the extraction of the sodium 
carbonate with water, or " hxiviation process " 

NaCl+H 2 S0 4 =NaHSO 4 +HCl , 
NaCl+NaHS0 4 =Na 2 S0 4 +HCl , 

Na 2 SO 4 +2C=Na 2 S+2CO 2 , 
Na 2 S+CaC0 3 =Na a C0 3 +CaS 

The salt cake process takes place in two stages, the reaction repre- 
sented by the second equation being carried on at a higher temperature 
in a reverberatory furnace The hydrochloric acid constitutes a 
valuable by-product 

The sulphate prepared by the salt-cake process is pulverized, and 
mixed with an equal weight of chalk and half its weight of coal or coke 
The mixture is then fused in a rotatory furnace At first only carbon 
dioxide is evolved, but at the end of the operation carbon monoxide is 
generated, and burns as it escapes into the atmosphere 

2CaCO 3 +2C=2CaO+4CO 

The sodium carbonate is lixiviated with water to separate it from the 
calcium sulphide or " alkali waste," and from other impurities such as 
sodium chloride, sulphate, silicate, and alummatc , calcium oxide, 
sulphite, and thiosulphate , iron oxide , and alumina 

Ammonia-soda Process This process is said 5 to have been devised 
by the apothecary Gerolamo Form in 1836 It was pcifected by 
Solvay, and on the continent of Europe it has largely displaced the 
older Le Blanc process A solution of sodium chloride is treated 
alternately with ammonia and carbon dioxide under piessurc, sodium 

1 Compare dc l^orcrand ibid 1895 120 1215 1897 124 1153 Matignon ibid 
1897 125 1033 

2 Compaie Reichert Zeitsch Kryst Mm 1909 47 205 

3 Pozzi Escot, Bull Soc chim 1919 [4] 25, 614 

4 For full details of alkali manufactuimg processes, see Lunge's Manufacture of 
Sulphuric Acid and Alkali 3rd ed (Gumey and Jackson 1911) vols 11 and m 

5 Vanzetti Chem Zeit 1910 34, 229 



ELASTIC 



BO doubt true that the opposite powers of at- 
traction and repulsion are frequently, perhaps 
constantly, energetic at the same instant , bat 
the effect produced m those cases arises from 
the difference of the two powers When the 
excess of the repulsive power above the at- 
tractive in different gases is comparatively 
small and insignificant, it constitutes that cha- 
racter which may be denominated neutral, and 
which I supposed to exist m the class of mixed 
gases which are not observed to manifest any 
sign of chemical union. I would not be un- 
derstood to deny an energetic affinity between 
oxygen and hydrogen, &c m a mixed state , 
but that affinity is more than counterbalanced 
by the repulsion of the heat, except m cir- 
cumstances which it is not necessary at present 
to consider 

Again, " Azotic gas comports itself with 
oxygen gas, in the changes occasioned by tern* 
perature and pressure, precisely like one and 
the same gas Is it necessary to have recourse 
to a supposition which obliges us to admit so 
great a difference of action without an osten- 
sible cause ?" It is possible thit> may appear 
an objection to a person who does not under- 
stand the theory, but it never can be any to 
one who does If a mixture of gas, such as 
atmospheric air, containing azote pressing 



SODIUM. 145 

Sodium carbonate forms three hydrates The decakydrate is mono- 
clinic, and has the density 1 455,* other values beuig 1 44^ at 17 C, and 
1 493 at the temperature of hqmd air 2 At 20 C 100 grams~~of Wftter 
dissolve 21 4 grams, reckoned a$ Na 2 CO a The heptahydrate appears to 
exist m both a rhombic $nd a metastable rhombohedral 8 form, but 
only between narrow limits of temperature Its solubility diminishes 
with rise of temperature The solubility of the monohydrdte* at 50 C 
is 47 5 grams Na 2 C0 3 in 100 grams of water The transition-points of 
the hydrates are given by Wells and McAdam 5 10 to 7 (D), 82 C , 
7 to 1 (F), 35 37 C , 10 to 1 (intersection CD and GF), 32 96 C 
Some of their solubility-data are given in the table, and the solubility- 
curve m fig 10 (p 146) 



Na 2 CO s ,10H 2 


Na 2 C0 3 ,7H 2 


Na 2 C0 8 HoO 




Grams 




Grams 




Grams 


Temperature, 
C 


Na 2 C0 3 in 
100 grams 


Temperature, 
C 


Na 2 C0 3 m 
100 grams 


Temperature, 
C 


Na 2 C0 8 in 
100 grams 




Water 




Water 




Water 


2784 


3420 


3035 


4350 


2986 


5053 


29 33 


3740 


31 82 


4516 


31 80 


5031 


3035 


40 12 


3286 


4628 


3537 


4967 


3145 


4325 


3437 


4822 


3791 


4911 


3172 


4421 


35 15 


4923 


4093 


4852 


32 06 


45 61 


3562 


5008 


4394 


4798 



The transition-temperature of the decahydrate to the heptahydrate 
is given by Richards and Fiske 6 as 32 017 C 

According to Beizelms, and also Schmdler, 7 the decahydrate m c\ir 
at 12 5 C becomes iransfoimcd into a pentahydrate The existence of 
other hydrates described is even more doubtful The boiling solution 
of sodium carbonate absorbs carbon dioxide from the atmosphere 
Dubovit? 8 found that exposure of the solid carbonate to atmosphcuc 
carbon dioxide and moisture for thirteen days pioduccd between 15 
and 20 per cent of the primary salt, NilKOj and that with a laigc 
excess of carbon dioxide and moisture complete conversion could J3i 
attained 9 

Sodium hydrogen carbonate, NaHCO 3 The pnmary salt is an mtei 
mediate product m the ammonia-soda pioccss, and cm be picpa-icd 

1 Compile Clarke Constants of Nature 2nd ed Washington 18SS, I 12(> Sihmdii 
Dichtiyieitsme^sungen Heidelbcig 1873 

2 Dewar Chem News 1902 85 277 

3 1 oe\\el Ann Chim Phys 1851 [3] 33 382 

4 Tipple Dissertation, Heidelberg 1899 

Wells and McAdam J Awer Chem Soc 1007 29 721 
e Richards and Fiske ibid 1914 36 485 

7 Schmdler Mag Pharm 33 14 319 

8 Dubovit7 Chem Zeit 1921 45 890 

9 For a double carbonate of sodium and potassium see the section on potassium 
carbonate (p 183) 

VOL II 10 



l4f ON MIXED ELASTIC FL0IW, 

waters on the surface of the globe were *rv* 
stantlj expanded into steam , surely the actioa 
of gravity would collect the molecute into aa 
atmosphere of similar constitution to the one 
we now possess , but suppose the whole mass 
of uater evaporated amounted in weight to 
SO inches of mercury, how could it support its 
own weight at the common temperature ? It 
would m a short time be condensed into water 
merely by its weight, leaving a small portion, 
such as the temperature could support, amount- 
ing perhaps to half an inch of mercury in 
weight, as a permanent atmosphere, which 
would effectually prevent any more vapour 
from rising, unless there were an increase of 
temperature Does not every one know that 
\vaterand other liquids can exist m a Torricel- 
lian vacuum at low temperatures solely by the 
pressure of \apour anting from them ? What 
need then of the pressure of the atmosphere in 
order to prevent an excess of vapourisation ? 

After having concluded that " without the 
pressure of the aerial atmosphere, liquids would 
pass to the elastic state/' Berthollet proceeds 
in the very next paragraph to shew that the 
quantity of vapour in the atmosphere may m 
fact be much more than would exist if the 
atmosphere were suppressed, and hence infers, 
" that the variations of the barometer oc- 



SODIUM. 147 



A double salt with the normal carbonate, 
occurs in Venezuela as Urao, and in Egypt as Trona. It is formed on 
concentrating a solution of tb^e two salts m m&leealaar propoirtao&s, 2 
and has been observed 3 to be a product of the effloresee&^e of the normal 
decahydrate during a period of twenty years 

Sodium percarbonate Na 2 C a O 6 The percarboixate is said 4 to be 
formed by the electrolytic oxidation of the normal carbonate, but it 
has not been isolated by this method A substance of the formula 
2Na 2 CO a ,3H 2 O 2 is obtained by the interaction of 3 molecules of hydrogen 
peroxide in aqueous solution and 2 molecules of sodium carbonate, 
the product being subsequently dried vn, vacuo 5 Other percarbon- 
ates have been described, 6 but their existence is still a subject of 
debate 

Sodium cyanide, NaCN The cyanide is formed by the action of 
hydrocyanic acid on sodium hydroxide , by heating sodium ferrocyamde 
in absence of air, or with sodium carbonate and charcoal , from atmo- 
spheric nitrogen by heating anhydrous sodium carbonate with iron- 
flings in air 7 , by heating sodium in ammonia at 350 C , and converting 
the resulting sodamide into cyanide by heating with charcoal 8 , and by 
the action of ammonia on a mixture of fused sodium cyanide, sodium, 
and charcoal, the sodium cyanamide, Na 2 CN 2 , formed being converted 
by the charcoal into sodium cyanide 9 

Sodium cyanide forms colourless crystals, very soluble in water, the 
weak acidic character of the hydrocyanic acid inducing hydrolytic 
dissociation, thus imparting to the solution a strong alkaline reaction, 
and an odour of hydrocyanic acid 10 The anhydrous salt is converted by 
boiling with 75 per cent alcohol into the dihydrate, a substance con- 
verted by slow evaporation over lime into the yellow, crystalline mono- 
hydrate u 

For the heat of formation of sodium cyanide from its elements, 
Berthelot 12 gives 22 6 Cal , and Joanms 13 23 1 Cal The heat of neutral- 
ization of hydrocyanic acid by sodium hydroxide is between 2 77 and 2 9 
Cal , its low value being due to the heat absorbed by the lomzation of 
the weak acid At 9 C the heat of solution of the anhydrous salt is 
5 Cal , and of the dihydrate 4 4 Cal 13 It is very poisonous 

Sodium thiocyanate, NaCNS The thiocyanate can be prepared by 
the action of sodium carbonate on thiocyanic acid or ammonium 
thiocyanate, or by fusion of potassium fenocyanidc with anhydrous 
sodium thiosulphate 

The anhydrous salt forms very deliquescent, rhombic plates, its heat 

1 Chatard Amer J Sci 1889 [3] 38 59 

2 Compare Habeimann and Kurtenacker Zeifoch anorq Chem 1909 63 f) r > 

3 Camming Chem News 1910 102 311 

4 Constam and Arthur von Hansen Zeitsch EleUwchem 1896 3,137 

5 Henkel & Co British Patent 1916 No 100997 

6 Compare Tanatar Ber 1899 32 1544, Wolff enstem and Peltner, Ber 1008 41 
280 Riesenfeld and Kemhold Ber 1909 42 4377 Wolffenstem Ber 1010 43 630 
Merck, German Patent 1909 No 213457 

7 Tauber Ber 1899 32 3150 

8 Behimger German Patent No 90999 

9 E6ssler German Patents Nos 124977 and 126241 

10 Compare James Walker Zeitsch physilcal Chem 1900 32 137 

11 Joanms Ann Chim Phys 1882 [5] 26, 484 

12 Berthelot Gompt rend, 1880 91 79 

13 Joanms loc cit 



166 OK MIXED ELASTIC FLUIDS 

does not sensibly condense the volume of any 
mixture, nor give oat heat, nor change the 
properties of the ingredients , its effect may 
be called solution or dissolution > for instance, 
when oxygen gas and azotic gas are mixed m 
doe proportion, they constitute atmospheric air, 
in which they retain their distinguishing pro- 
perties 

It is upon this supposed solution of one 
elastic fluid in another that I intend to make a 
few observations That I have not misre- 
presented the author's ideas, will, 1 think, ap- 
pear from the following quotations " When 
different gases are mixed, whose action is con- 
fined to this solution, no change is observed in 
the temperature, or in the volume resulting from 
the mixture, hence it may be concluded, that 
this mutual action of two gases does not pro- 
duce any condensation, and that it cannot sur- 
mount the effort of the elasticity, or the af- 
finity for caloric, so that the properties of each 
gas are not sensibly changed " " Although 
both the solution and combmition of two 
gases are the effect of a chemical action, which 
only differs in its intensity, a real difference 
may be established between them, because 
there is a very material difference between the 
results the combination of two gases always 
leads to a condensation of their volume, and 



SODIUM. 140 

Sodium hypoborate, NaH 3 BO On cooling the mixture produced: by 
the interaction of a very concentrated solution of potassium hydroxide 
and boron hydride, B 4 H JC , the very deliquescent sodium hypoborate & 
obtained 1 

Sodium berates The anhydrous metaborcAe* NaBO^ is formed by 
fusing borax with sodium carbonate, being obtained in hexagonal 
prisms, m p 2 966 C , density 3 2571 between 17 and 97 C When 
the syrup-like solution obtained by concentrating equivalent propor- 
tions of sodium hydroxide and bone acid or borax is allowed to crystallize 
over concentrated sulphunc acid, the tetrahydrate separates in trichmc 
crystals The d^hydrate 4s and other hydrates 5 have also been de 
scribed The aqueous solution of the metaborate has an alkaline 
reaction, due to hydrolytic dissociation 6 The orthoborate is formed by 
fusing boric anhydride with sodium peroxide 7 

The most important ^borate of sodium is dwodium tetraborate or 
boraae, Na 2 B 4 O 7 ,10H 2 O ) found in Thibet as the mineral t^ncal } and also IB 
California The native variety is purified by crystallization, but most 
of the borax of commerce is obtained by fusing native boric acid with 
sodium carbonate 

The anhydrous salt is obtained by heating the decahydrate, and is 
a white substance of density 8 2 367 Its melting-point is given as 
561 C , 9 730 C , 10 741 C , n and 878 C , 12 the fused substance solidify 
nig to a colourless, transparent, vitreous mass known as the " borax 
bead " In the melted state it dissolves metallic oxides, producing 
characteristic colorations, and finds application in analysis It is also 
employed in soldering metals to remove the superficial layer of oxide, 
and to prevent oxidation during the process by excluding the air 
Its specific heat is 229 between 17 and 47 C (Kopp 13 ), and 2382 
between 16 and 98 C (Regnault u ) Its heat of formation is 748 1 
Cal 15 

The decahydrate or ordinary borax forms monochmc ciystals of density 
1 723 (Hassenfratz 16 ) , 01 1 694 at 17 C , and 1 728 at the temperature 
of liquid air (Dewar 17 ) Its specific heat 18 is 385 between 19 and 
50 C A pentahydrate belonging to the rhombohedial division of the 
hexagonal system crystallizes above 60 C Its density 19 is 1 815 The 
pentahydrate is stable from 60 C , the transition-point from the 
decahydiate, to 125 C At 130 C the stable foini is the tnhydtate t 

1 btocl and Kuss JBcr 1914 47 blO, sec potabsmin liypoboiatt p Ibj 

2 van Kloostei //eittch anonj Chem 1910 69 122 

3 Kegnault Poyy Annalen 1841 53 bO 243 

4 Dukclaki Zeitwh anorg Chem 1900 50 *8 
Atteiberg ibid , 1900 48 307 

6 Compare Jimes Wall cr Zeitt>ch phy^ilal Chem 1900 32 137 

7 Mixter Amir J 8ci 1908 [4] 26 125 

8 Jhilhol, Ann Chim Phys 1847 [ij 21 415 
8 Carncllcy Ttant> Che)a /S'oc 1878 33 273 

10 Ponomaicv Ztifoch anoxj Chun 1914 89 Jb3 

11 Dana and JHooti Tnmt> % amday boc 1920 15 180 
1 Victoi Mcyci and Kiddle Bet 1893 26 2448 

13 Kopp Inualuibuppl 1804-05 3 i 289 

14 Regnault Poy<j Innalen 1841 53 00, 243 

1 Bcrthelot Ann Chun Phyt> 1873 [4] 29 470 

16 ( ompaie Olarke Constants of Nature, 2nd ed Washington 1888 1,107 

17 Dewar Chem 2*ew$ 1902 85 277 

18 Kopp loc cit 

19 Payen, Jakresbtr , 1828, 171 



168 ON MIXED ELASTIC ?Ltnr>* 

clastic fluids are endued with the force of 
cohesion ; but this he applies only to hetero- 
geneous particles He certainly does not 
mean that the particles of homogeneous elastic 
fluids possess the force of cohesion, 

Newton has demonstrated from the phe- 
nomena of condensation and rarefaction that 
elastic fluids are constituted of particles, which 
repel one another by forces which increase 1$ 
proportion as the distance of their centres 
diminishes* in other words, the forces are 
reciprocally as the distances This deduction 
will stand as long as the Laws of elastic fluids 
continue to be what they are What a pity it 
is that all who attempt to reason, or to theorise 
respecting the constitution of elastic fluids, 
should not make themselves thoroughly ac- 
quainted with this immutable Law, and con- 
stantly hold it m their view whenever they 
start any new project ! When we contemplate 
a mixture of oxygenous and hydrogenous gas, 
what does Berthollet conceive, are the particles 
that repel each other according to the New- 
tonian Law ? The mixture jnust consist of 
such y and he ought m the very first instance 
to have informed us what constitutes the 
unity of a particle in his solution If he 
grants that each particle ot oxygen retains its 
unity, and each particle ot i vc r > <." does the 



SODIUM 



151 



water it yields h\ drogcn peroxide At 22 C its solubility is 7 1 grams 
g m 100 grams of water, the solution being strongly alkaline. 



DETECTION AND ESTIMATION OF SODIUM. 

All sodium salts impart a characteristic yellow coloration* to tixe 
Bunsen flame, the test being so delicate as to detect 3 x lOr gratos 
The extreme delicacy of the test and the wide distribution of traces of 
sodium chloride throughout the atmosphere render the persistence or 
otherwise of the coloration an important factor in determining the 
presence or absence of sodium m the substance under examination 
In the spectroscope, sodium gives a yellow line, coincident with the 
D-lme of the solar spectrum 

Most salts of sodium are soluble in water, but the pyroantimonate, 
Na 2 H 2 Sb 2 O 7 , dissolves only to the extent of 1 part in 350 parts of 
boding water It is produced by addition of potassium pyroantimonate 
to a neutral or alkahne solution of a sodium salt The double chloride 
with tin, and the double sulphite with platinum, Na 6 Pt(SO 3 ) 4 ,7H 2 O, are 
less soluble than the corresponding potassium salts 

In quantitative analysis sodium is estimated as sulphate, formed by 
evaporation with concentrated sulphuric acid If potassium be present, 
its amount is determined by precipitation as double chloride with 
platinum from the solution of the mixed sulphates x 

The salts of sodium react with a solution of potassium nitrite and 
the nitrates of bismuth and caesium, yielding a yellow, crystalline 
precipitate of the formula 5Bi(NO 2 ) 3 ,9CsN0 2 ,6NaNO 2 This reaction 
is applicable to the detection and estimation of sodium 2 

1 On the separation from potassium and rubidium, compare Wernadski, Bull Soc 
fran$ Mm 1913 36 258 

2 Ball, Trans Chem Soc , 1909 95, 2126 , 1910 97, 1408 



170 ON MIXES ELASTIC FttTIM, 

cognisable to any of the senses. It certain 
requires an extraordinary stretch of the imaj 
nation to admit the affirmative. 

One great reason for the adoption of th 
or any other theory on the subject, arises fro 
the phenomena of the evaporation of wat< 
How is water taken up and retained in tl 
atmosphere? It cannot be m the state 
vapour, it is said, because the pressure is t< 
great there must therefore be a true chemic 
solution But when we consider that the si 
face of water is subject to a pressure equal 
30 inches of mercury, and besides this pressui 
there ts a sensible affinity between the particl 
of water themselves , how does the tnsen^il 
affinity of the atmosphere for w ater overcon 
both these powers ? It is to me quite mexp 
cable upon this hypothesis, the leading object 
which is to account for this very phenomeno 
Further, if a particle of air has attached 
particle of water to it, what reason can 1 
assigned why a superior particle of air shou 
rob an inferior one of its property, wh< 
each particle possesses the same power ? If 
portion of common salt be dissolved in wat 
and a little muriatic acid added , is there ai 
reason to suppose the additional acid displac 
that already combined with the soda, and th 
upon evaporation the salt is not obtained wi 



POTASSIUM 153 

at dull redness, and subsequently raising the temperature of small 
portions of the carbonaceous mass to bright redness, the molteai metal 
being tapped off The fused hydroxide can also be allowed to flow over 
heated charcoal, and the metal distilled off< 

When equivalent weights of sodium and potassium hydroxide are 
mixed, and fused in absence of air, sodium monoxide is formed, hydrogen 
evolved, and potassium distils at a temperature of about 670 C The 
metal can be condensed, and the process is claimed to be applicable to 
its manufacture 2 

Latterly the production of potassium by the electrolytic process 
has become of industrial importance, partly on account of the punty 
of the product, and partly because the attendant nsk is much less than 
with the chemical methods The ordinary Castner 8 process for the 
isolation of sodium is inapplicable to potassium, Lorenz 4 having shown 
that part of the potassium is dissolved in the molten state by the fused 
hydroxide, and part is vaporized and after condensation in minute 
drops is diffused throughout the liquid mass The effect is that the 
liberated metal tends to combine with the anion at the anode The 
difficulty is avoided by surrounding the iron- wire cathode with a cylinder 
of magnesite to prevent diffusion of the metal to the anode, by employ- 
ing as low a temperature as possible, and by excluding air An anode 
of sheet iron is immersed in the fused hydroxide outside the magnesite 
chamber As substitutes for the hydroxide, potassium nitrate, 5 and 
also potassium chloride with an admixture of fluoride to lower the 
melting point, 6 are employed With the nitrate the cathode is an 
aluminium vessel 

Physical Properties Potassium is a soft, silver white 7 metal of 
high lustre Its melting point is given as 60 C , 8 62 4 C , 9 62 5 C , 10 
and 63 5 C u A wide discrepancy exists between the values given foi 
the boilmg-pomt, among them being 667 C 12 , 667 C at 760 mm 
pressure, 13 719 to 731 C , 14 757 5 C , 15 365 C at mm , 16 and about 
90 C in the vacuum of the cathode light 17 For the density are recorded 
the values 8629 18 and 859 19 at C , 8621 20 at 20 C , and 851 

1 Netto British Patents 1887 Nos 14602 and 17412 

Wickel and Loebel German Patent 1919 No 307175 
d Castner British Patent, 1890 No 13356 

4 Lorenz and Claike Zut&ch 1 kktrochem 1903 9 209 compare Le Blanc and 
Biodc ibid 1902 8 817 

Darling and 1 on cst German Patent No 83097 

6 Stocick ibid No 08335 

7 Bomemann (Zeitsch angew Chun 1922 35 227) has described \ method of 
pieparmg and preserving the metal untarnished 

8 Masmg and 1 immann /uk></t anory Chun 1910 67 183 

9 (jucitlei and Pnani Ztittch Mdalll utule 1919 II 1 

10 Bunsen Annalcn 1863 125 308 Holt and buns ./Van* Chun bo( 1894 65 432 
Kurnikoff and Pushm Zeitich anory Chun 1902 30 109 van Blcis^yk ibid , 1912 

74 lr >- 

11 Kengadc Compt tout 1913 156 1897 Ball hoc chim 1914 |4| 15 130 

12 Pumin Trail? Chem bor 1889 55 320 

13 HUnscn Ber 1909 42 210 

14 Carntlley and Williams Trans Chem hoc 1879 35 503 1880 37 125 
1 Ruff and lohannscn Ber 1905 38 3601 

16 Hansen loc cit 

17 Krafft and Bcigfcld Ber 1905, 38 254 

18 Vicentim and Omodei W led Annalen Beibl 1888 12 176 

19 HackspiU Compt tend 1911 152,259 

20 Richards and Brink J Amer Chem Soc , 1907 29, 117 



172 ON MIXED ELASTIC FLUIDS 

tacfaed to it , but this is impossible , one half 
of the atoms of oxygen must then take two of 
hydrogen, and the other half, one each But 
the former would be specifically lighter than 
the latter, and ought to be found at the top of 
the solution $ nothing like this is however 
observed on any occasion 

Much more might be advanced to shew the 
absurdity of this doctrine of the solution of on^ 
gas in another, and the insufficiency of it to 
explain any of the phenomena j indeed I 
should not have dwelt so long upon it, had 
I not apprehended that respectable authority 
was likely to give it credit, more than any ar- 
guments in its behalf derived from physical 
principles 

Dr Thomson, m the 3d Edition of his 
System of Chemistry, has entered into a dis- 
cussion on the subject of mixed gases y he 
seems to comprehend the excellence and de- 
fects of my notions on these subjects, with 
great acuteness lie does not conclude with 
Berthollet, that on my hypothesis, " there 
\\ould not be any augmentation of volume 
when aqueous and ethereal vapour was com- 
bined with the air," which has been so com- 
mon an objection There is however one 
objection which this gentleman urges, that 
shews he does not completely understand the 



POTASSIUM. 



155 



surface of the metal soon tarnishes, owing to the effect of moisture 
The metal also combines energetically with oxygm and the halogens, 
an example being the liberation of silicon and boiroji feom their oxides 
and chlorides Its solution in hqmd Ammonia reacts with ozone, 1 

Potassium Ion With the exception of rulbidxtim and caesium, 
potassium has the greatest electroaffinity or tendency to lonization, a 
fact regarded by Abegg and Bodlander as according with the ready 
solubility of most of its salts, and the comparatively slight tendency of 
its ions to form complex salts or hydrates The potassium salts are 
strong electrolytes, being highly dissociated in dilute aqueous solution 
Only those with coloured anions yield coloured solutions, an indication 
that the potassium ion is colourless The conductivity of the potassium 
ion is 64 5 at 18 C , and 74 8 at 25 C The transport-number 2 is 
0514 

Atomic Weight In connexion with the atomic weight of sodium, 
reference has been made to the general methods employed by Berzehus, 
by Stas, and by Mangnac in determining the atomic weights of sodium, 
potassium, silver, chlorine, bromine, and iodine At this point it will 
suffice to summarize the results obtained by these methods, and those 
denved from the work of modern investigators 

There are numerous early determinations of the composition of 
potassium chlorate, giving the ratio KC10 3 KC1 The results are 
summarized in the table 



Experimenter 


Year 


KC10 3 KC1=100 x, where x= 


Berzehus 3 


1818 


60851 00006 


Penny 4 


1839 


60 8225 00014 


Pelouze 6 


1842 


60 843 0053 


Mangnac 6 


1842 


60 839 0013 


Gerhardt 7 


1845 


60 8757 00020 


99 


99 


60 94870 0011 


Maumene 8 


1846 


60791 00009 


Stas 9 


1860 


60 8428 00012 


99 


99 


60 8490 00017 



In Sta&'s first series of experiments the chloiatc was decompose 
by heat , in the second, it was decomposed by hydiochlonc aeid Irr 
the fou going results Clarke 10 has computed the weighted mean (p S 

KC1O 3 KC1=100 60 8460 00038 

1 Compare sodium p 86 

2 Tolman J Amer Ghem Soc 1911 33 121 

3 Berzelms Tromm&dorf s A T J Pharm 1818 11 2 44 Pogg Annalen 1826 8 1 
Lehrbuch dcr Chemie 5th ed Dresden 1843-1848 3,1189 

4 Penny Phil Trans 1839 129, 20 

5 Pelouze Compt rend 1842 15 959 

6 Marignac (Euvres Completes Geneva 1902, I, 57 

7 Gerhardt Compt rend 1845 21 1280 

8 Maumene Ann Chim Phys 1846 [3] 18 71 

9 Stas, (Euvres Completes, Brussels, 1894 i, 404 

10 Clarke A Recalculation of the Atomic Weights Washington Smithsonian Miscellaneous 
Collections, 2nd ed , 1897 3rd ed , 1910 



174 ON MIXEfc ELASTIC FJLUIDS* 

root of the spaces inversely, that is, aa 
* 1/2 1, or as 1 26 I nearly. In such a 
mixture as has just been mentioned, then* 
the common hypothesis supposes the pressure 
pf each particle of gas to be 1 26 , whereas 
mine supposes it only to be I , but the sum 
of the pressure of both gases on the containing 
vessel, or any other surface, is exactly the same 
on both hypotheses 

Excepting the above objection, all the rest 
which Dr Thomson has made, are of a nature 
not so easily to be obviated , he takes notice 
of the considerable time which elapses before 
two gases are completely diffused through each 
other, as Berthollet has done, and conceives 
this fact, makes against the supposition, that 
one gas is as a vacuum to another He further 
objects, that if the particles of different gases 
are inelastic to each other, then a particle of 
oxygen coming into actual contact with one of 
fcydrogen, ought to unite with it, and form a 
particle of water , but, on the other hand, he 
properly observe, that the great facility with 
which such combinations are effected in such 
instances a^ a mixture ot nitrous and oxygen 
gas, is an argument in favour ot the hypo- 
thesis Dr Ihomson foundb another objection 
upon [he facility of certain combinations, when 
of the ingredients is in a nascent forno , 



POTASSIUM 



157 



Experimenter 


Year 


Ag B^r^lOO #, where #~ 


Mangnac x 
Stas 2 


1848 
1865 


no 51 * oo<r> 

110346+0002 



The weighted mean is 

Ag KBr=100 110 34590 0019 (F) 

Five analyses of potassium iodide by Mai irrrido 8 in 1843 gave 

Ag KI^lOO 153800 (G) 

From the foregoing seven mean results lettered from A to G the 
atomic weight of potassium can be induced For this purpose the ante 
cedent data calculated by Stas from his experiments have been chosen, 
(O=16), Cl=35 457, Br=79 952, 1=126 850, Ag=107 930 The values 
obtained for the atomic weight of potassium are 



(A) 39 136 

(B) 39 438 



(C) 38739 

(D) 39 138 



(E) 39 113 

(F) 39 144 



(G) 39 038 



The values (B) and (C), derived from analyses of potassium bromate 
and lodate, are obviously worthless The results (A), (D), and (F) 
depend mainly on the careful work of Stas, and their arithmetic mean 
is 39 139 The results (E) and (G) are based on Mangnac' s work on 
potassium chloride and iodide, and approximate reasonably to those 
of Stas Excluding (B) and (C), the arithmetic mean of the results is 

K=39 113 

From his own experiments Stas induced the value K=39 142, and 
recalculation in terms of 16 of the value accepted as the atomic 
weight of potassium for many years gives 39 14 or 39 15 

The work of modern investigators, particularly that of Richards 
and his coadjutors at Harvard, has pioved Stas's value foi the atomic 
weight of silver to be too hi^h, and his iclative values for silver and 
chlorine to be erroneous These inaccuracies vitiate the piecedmg 
calculations , but there would be no advantage in dei ivmg them from 
more accurate antecedent di,ta, as modern research has disclosed 
appreciable eriors in even the most painstaking of the earlier work, 
and furnished more reliable ratios for inducing the atomic weight of 
potassium In the subjoined account the calculations have been 
made with the atomic weights O=16000, Ag =107 880, Cl=35 457, 
Br=79 91 C, N = l 1008 

In connc \ion with their work on cTsmm, Richards and Arehib ild 4 in 
1 903 made two analyses of potassium chloride, the results being 

AgCl KC1 = 100 520215, 

1 Mangnac (Euvres Completes Geneva 1902 I 82 

2 Stas (Euvres Completes Brussels 1894 I 747 

3 Mangnac (Euvres Completes Geneva 1902 i 86 

4 Richards and Archibald Proc Amer Acad 1903 38 4 )7 



J76 OH MIXEP ELASTIC FLUIDS, 

air , but the same ball, being made into a 
thousand smaller ones of -# of an inch di- 
ameter, and falling with the same velocity, 
meets with 10 times the resistance it did 
before because the force of gravity increases 
as the cube of the diameter of any particle, 
and the resistance only as the square of the 
diameter Hence it appears, that in order to 
increase the resistance of particles moving in 
any medium, it is only necessary to divide 
them, and that the resistance will be a maxi- 
mum when the division is a maximum We 
have only then to consider particles of lead 
falling through air by their own gravity, and 
we may have an idea of the resistance of one 
gas entering another, only the particles of lead 
must be concened to be n\finitely small, if I 
may be allowed the expression Here we 
shall find great resistance, and yet no one, I 
should suppose, will say, that the air and the 
lead are mutually elastic 

The other two objections of Dr Thomson, 
I shall wave tht consideration of at present 

Mr Murray has lately edited a system of 
chemistry, in which he has given a very clear 
description of the phenomena of the atmo- 
sphere, and of other similar mixtures of elastic 
fluids He has ably discussed the different 
theories that have been proposed on the subject, 



POTASSIUM. 159 

Neglecting the work of Richards and Archibald, which lacks the 
experimental accuracy of the later investigations, five modern values 
for the atomic weight of potassium fall withm the limits of 80 095 and 
89 098, and indicate the great probability of the value 

K=390% 

The current table of the International Committee on Atomic 
Weights gives l 

K=3910 

Alloys of Potassium and Sodium 2 Potassium and sodium unite to 
an alloy of the formula Na 2 K 3 In absence of air at 200 to 250 C , 
potassium reacts with sodium hydroxide to form a liquid alloy NaK 2 ' 4 

3K+NaOH=KOH+NaK 2 

At 350 C sodium and potassium hydroxide interact in accordance with 
the equation 

8Na+2KOH=2NaOH+NaK 2 

At 225 to 275 C the reaction is different, and is expressed by the 
equation 

2Na+KOH=NaOH+NaK 

On exposure to air these alloys ignite instantly 



COMPOUNDS OF POTASSIUM 

Potassium hydride, KH Moissan 5 prepared the hydride by a 
method analogous to that employed by him for the corresponding sodium 
derivative, the excess of potassium being dissolved by liquid ammonia 
Ephraim and Michel 6 passed hydrogen into potassium at 350 C , and 
found the reaction to be promoted by the presence of calcium Ihe 
hydride forms white crystals of density 80 The vapour-tension for each 
temperature-interval of 10 between 350 and 410 C corresponds with 
the values 56, 83, 120, 168, 228, 308, and 430 mm respectively 7 In 
chemical properties potassium hydride resembles the sodium compound, 
but is less stable Its stability is greater than that of rubidium 
hydride or caesium hydride Carbon dioxide converts it into potassium 
formate 

Potassium fluoride, KF The fluoride is produced by the mterietion 
of hydrofluoric acid and potassium carbonate or hydroxide by heating 
potassium sihcofluonde or borofluoride with lime , and by the action of 
potassium on fluorine, hydrofluoric acid, or silicon fluoride or bonde 

The anhydrous salt forms crystals belonging to the cubic system, 

1 Compare Hmrichs, Compt rend 1909 148 484 Dubreuil Bull Soc chim 1910 
[4] 7 119, W A NoyesandH C P Weber J Amer Chem Soc 1908 30 13 
1 or potassium amalgam see this series Vol III 

3 Van Bleiswyk Zeitsch anorg Chem 1912 74 152 

4 Jaubert Ber , 1908 41 4116 

5 Moissan Compt rend 1902 134 18 compare Troost and Hautefeiulle ibid , 1874 
78 807 Elster and Geitel Physikal Zeitsch , 1910 n 257 

6 Ephraim and Michel Hdv Chim Acta 1921 4 762 

7 Compare Keyes, J Amer Chem Soc , 1912 34, 779 



178 ON MIXED ELASTIC FLUIDS 

retained in mixture by that force of adhesion, 
which, exerted at the surfaces of many bodies* 
retains them m contact with considerable 
force " He supports these notions at length 
by various observations, and repeats some of 
the observations of Berthollet, whose doctrine 
on this subject, as has been seen, is nearly the 
same 

Before we animadvert on these principles, 
it may be convenient to extend the first a little 
farther, and to adopt as a maxim, " that be- 
tween the particles of pure gases, winch arc 
capable under any circumstances of combining, 
an attraction must always be exerted " This, 
Mr Murray cannot certainly object to, in the 
case of steam, a pure elastic fluid, the par- 
ticles of which are known in certain circum- 
stances to combine Nor will it be said that 
steam and a pemanent g is are different , for 
he justly obbenes, " this distinction (between 
gases and vapoirs) is merely relative, and 
arises iroin the dillucnce ot temperature at 
which tneyart farmed, the state with regard 
to each, uhile they exist in it, is prcciscl) the 
same " Is steam then consumed of particles 
in which the attraction is so tar exerted as to 
prevent their separation * No they exhibit 
no traces of rttraction, more than the like 
number of particles ot oxygen do, when in 



POTASSIUM 161 

(" Abraumsalze ") contain 55 to 65 per cent of carnallite, associated 
with 20 to 25 per cent of rock-salt, 10 to 20 per cent, of kiesente, 
MgS04,H 2 O, and 2 to 4 per cent./ of tachydnte, CaQ 2 ,2Mga 2 ,12H 2 O 
The technical preparation of potassium chlonde from these deposits 
depends on the ready solubility of carnallite, and the crystallization of 
potassium chloride from hot saturated solutions of this substance * 
Kamite is employed as a source of potassium chloride, and the com- 
pound is also obtained by fractional crystallization of the salts present 
in sea- water and m the ash of seaweed 

A process for the production of potassium chlonde from orthoclase 
was patented by Bassett, 2 but has not been worked technically It was 
discovered independently and investigated by Ashcroft, 3 and consists 
in heating finely divided orthoclase with sodium chloride in equal 
proportion by weight at 900 to 1000 C , 85 per cent of the potassium 
in the mineral being replaced by sodium in accordance with the scheme 

K 2 O,Al 2 O 3 ,6Si0 2 +2NaCl =^= Na 2 O,Al 2 3 ,6Si0 2 +2KCl 

The potassium chlonde can be separated from the insoluble sodium 
felspar by lixiviation, and from the excess of sodium chloride by frac- 
tional crystallization This process might afford a new method for the 
manufacture of potassium chloride It has also been found possible 
to extract the salt from the dust of the blast-furnace 4 

Potassium chloride forms colourless cubes, and has also been obtained 
in octahedra, rhombododecahedra, and icositetrahedra Its melting- 
point is given as 762 C , 5 772 3 C , 6 774 C , 7 775 C , 8 778 C , 9 and 
790 C 10 It volatilizes without decomposition, the molecular weight 
derived from the vapour density, 11 and also that from the depression of 
the freezing point of mercuric chloride, 12 corresponding with the simple 
formula KC1 For the density are given the mean value 1 977, 13 
and also 1 989 at 16 C , 14 1 991 at 20 C , 15 1 994 at 20 4 C , 16 1 951 at 
23 4 C , 17 1 612 at the melting point 18 The specific heat is given as 
171 between 13 and 46 C , 19 1730 between 14 and 99 C , 20 1840 
between 20 and 726 C , and for the fused salt 2671 between 807 and 

1 Compare van' t Hoff and Meyerhoffer Sitzungaber K Akad Wiss Berlin 1897 4S7 
Zeitsch physikal Chem 9 lB99 30 64 Meyerhoffer, German Patents 1896 Nos 92812 and 
98344 

2 H P Bassett USA Patent 1913, No 1072686 

3 Ashcroft Chem Trade J 1917 61 529 

4 Chance, ibid 1918 62, 44 J 8oc Chem Ind 1918, 37, 87 
Ramsay and Eumorfopoulos Phil Mag 1896 41 360 

f Plato Zeitsch physilal Chem 1906 55 721 

7 Schatfer Jahrb Mm Beil Bd 1919 43 132 

8 Arndt Zeitsch Elektrochem 1906 12 337 Haigh J Arner Chun >Soc 1<U2 34 
1137 Korreng Jahrb Mm Beil Bd 1914 37 51 

9 Huttncr and Tammann Zeitsch anorg Chem 1905 43 215 

10 Schemtschushny and Rambach J Russ Phys Chem boc 1909 41 1785 

11 Nernst Nachr K Oes Wiss Gottingen 1903 75 
1 Beckmann Zeitsch anorg Chem 1907 55 180 

13 Compare Claike Constants of Nature 2nd ed Washington 1888 i 20 and 21 

14 Retgers Zeitsch physilal Chem 1889 3 289 

15 Haigh J Amer Chem Soc , 1912 34 1137 

10 Knckmeyer Zeitsch physikal Chem 1896 21, 53 

17 Buchanan Proc Chem Soc 1905 21 122 

18 Quinoke Pogg Annalen 1869 138 141 

19 Kopp, Annalen Suppl 1864-5, 3, i 289 

20 Regnault Pogq Annalen 1841, 53 60 243 

VOL II 11 



180 ON MIXED ELASTIC FLUIDS 

facility , nay, these last exercise this solvent 
power with more effect than the former , for, 
hydrogen can draw up carbonic acid from the 
bottom to the top of any vessel, notwithstand- 
ing the latter is 20 times the specific gravity of 
the former One would have thought that a 
force of adhesion was more to be expected in 
the particles of steam, than in a mixture of 
hydrogen and carbonic acid But it is the 
business of those who adopt the theory of the 
mutual solution of gases to explain these 
difficulties 

In a mixture where are 8 particles of oxygen 
for 1 of hydrogen, it is demonstrable that the 
central distances of the particles of hjdro^en 
are at a medium twice as great as those of 
oxygen Now supposn g the central distance 
of two adjacent particles of hydrogen to be 
denoted by P2, query, what is supposed to 
be the central distance of any one pirticlc of 
hydrogen fiom that one particle, or those 
particles of oxygen with which it is connected 
by this weak chemical union ? It would be 
well if those who understand and maintain 
the doctrine of chemical solution would re- 
present how they conceive this to be 3 it would 
enable those who are desirous to learn, to obtain 
a clear idea of the system, and those who are 
dissatisfied with it, to point out its defects with 



POTASSIUM 163 

The mean density is 2 690, 1 other values found being 2 756 at 20 C , 2 
2679 at 234 C , 3 and 273 at 25 C 4 The specific heat is 01182 
between 16 and 98 C , 5 or 102 between the temperature of liquid 
air and 15 C 6 The molecular electee conductivity of potassmm 
bromide between 745 2 and 868 6 C is given by the formula 7 

^==90 09+0 1906(^-750) 

The heat of formation of potassium bromide from the elements is $ , 

given as 95 3 Cal 8 and 95 6 Cal 9 At 20 C 100 grams of water dissolve !| 

65 grams of the bromide 10 , and at 25 C 100 grams of ethyl alcohol 
dissolve 142 gram u 

In aqueous solution potassium bromide reacts with bromine, poly- 
bromides with the formulae KBr 3 and KBr 5 being formed in solution 12 
In the neighbourhood of its melting-point the salt evolves bromine 
freely 1S Potassium bromide finds application in medicine as a soporific, 
and in photographic development as a " restramer " 

Potassium iodide, KI The iodide is obtained by neutralizing the 
carbonate with hydnodic acid, and also by the interaction of potassium 
hydroxide and iodine, the lodate simultaneously produced being con- 
verted into iodide by heat or by the action of a reducer such as carbon 

6KOH+3I 2 =5KI+KI0 3 +3H 2 O 

It is manufactured by the action of iron-filings on iodine in presence 
of water, the soluble iodide Fe 3 I 8 formed being decomposed by potassium 
hydroxide, a process accompanied by precipitation of the oxide Fe 3 O 4 
and formation of a solution of potassium iodide The salt crystalli/es 
on concentration of the aqueous solution It can also be prepared from 
the ashes of seaweed, and from the lodate present in Chile saltpetre 

Potassium iodide forms crystals belonging to the cubic system, 
melting at 677 3 C , 14 680 C , 15 684 1 C , 16 705 C , 17 or 722 7 C 18 Its 
density is given by various investigators as 3 079, 19 3 043 at 24 3 C , 20 
and 3 115 at 25 C 21 The specific heat is given as 0766, 22 and 0819 

1 Schroder Dichtigkeitsmessungen Heidelberg 1873 compare Claike Constants of 
Nature, 2nd ed Washington 1888 I 31 

- Krickmeyci Zeitsch physikal Chem , 1896 21 53 

3 Buchanan Proc Chem Soc 1905 21 122 

4 Richards and Mueller J Amer Chem Soc 1907 29 G39 compare Biunner 
ibid 1904 38 350 Lorenz, Frei and Jabs Zeifach physikal Chan 1908 61 468 

5 Regnault Porjg Annalen 1841 53 60 243 

6 Nordmeyer Ber Dent physikal Oes 1908 6 2021 

7 Jaeger and Rapma Zeittch anorg Chem 1920 113,2? 

8 Thomson J prakt Chem 1875 [2] II 242 

9 B(rtholot Thermochimie Pans 1897 I 181 

10 do Coppct Ann Chim Phys 1883 [5] 30 416 

11 Turner and Biss( tt Trans Chem Soc 1913 103 1904 

12 Boiicke Zeitsch MeLtrochem 1905 n 57 

13 Guareschi Atti R Accad Sci Torino 1913 48 735 

14 McCiae Wied Annalen 1895 55 95 

15 Huttner and Pammann Zeitsch anorg Chem 1905 43 215 

16 Rassow, Zeitwh anorg Chem 1920 114 117 

17 Ruff and Plato Ber 1903 36 2357 

18 McCrae loc cit 

19 Compare Clarke Constants of hat are 2nd ed Washington 1888 i 34 

20 Buchanan Proc Chem Soc 1905 21 122 

21 Baxter and Brink J Amer Chem Soc 1908 30 46 

22 Nernst and Lindemann, Sitzungsber K Akad Wiss Berlin 1910 247 



182 ON MI*EZ> ELASTIC FLUIDS. 

the position which I maintain, that if the at- 
mosphere were annihilated, we should have 
little more aqueous vapour than at present 
exists in it Upon which I shall only remark, 
that if either of those gentlemen will calculate, 
or give a rough estimate upon their hypothesis, 
of the quantity of aqueous vapour that would be 
collected around the earth, on the said supposi- 
tion, I will engage to discuss the subject with 
them more at large 

In 1802, Dr Henry announced very 
curious and important discovery, which was 
afterwards published in the Philosophical Trans- 
actions , namely, that the quantify of any gas 
absorbed by water is increased in direct />?0- 
portipn to the pressure of the gas on tht sur- 
face of the water Previously to this, 1 was 
engaged in an int* gat '. . of the quantity of 
carbonic acid in the atmosphere , it was mat- 
ter of surprise to me that lime water should so 
readily manifest the presence of carbonic acid 
in the air, whi'st pure \vatei by exposure for 
anv length of time, gave not the least traces 
of that acid I thought that length of time 
ought to compensate for weaknesb of affinity 
In pursuing the subject I found that the 
quantity of this acid taken up by water was 
greater or less in proportion to its greater or 
less density m the gaseous mixture, incumbent 



POTASSIUM 165 t 

chlorite is formed analogously to that of sodium hypochlonte by the 
action of chlorine on a dilute aqueous solution of the hydroxide at low * 

temperatures , by the interaction of potassium salts a&d bleaching- * 

powder solution , and by the electrolysis of potassium-chloride solution f 

without a diaphragm It is also formed to some extmt by passing an <$ 

alternating current through a sofaticm of potassium chloride * The ' 
heat of formation of the substance in aqueous solution is given as S4 S5 "I 

Cal 2 and 88 Cal 3 This solution, was formerly employed as a bleaching ^ J| 
agent, under the name " Eau de Javelle " * 1 

Potassium chlorate, KC1O 3 The chlorate is obtained by methods 1 

similar to those employed for the corresponding sodium salt The r 

electrolysis of the chloride 4 affords a means of manufacture, and it is ^ 

also obtained by the interaction of potassium chloride and calcium \ 

chlorate Large quantities are made by the electrolytic oxidation of 1 

sodium chloride to chlorate, and conversion of this salt into potassium 
chlorate by treatment with potassium chloride Sodium chlorate is 
much more soluble than potassium chlorate, so that the electrolytic 
process is not impeded by crystallization of the salt 

The electrochemical formation of chlorate from hypochlonte is 
regarded by Kmbbs and Palfreeman 5 as involving two reactions, repre- 
sented by the equations 

OC1 / +2HOC1=C10 3 / +2H +2C1' , 
20C1'+2H +2C1 / =2HOC1+2C1 / 

The net result is the disappearance of three hypochlonte ions, with 
formation of 1 chlorate ion and 2 chloride ions Although appar- 
ently termolecular, the first reaction is unimolecular, since the con 
centration of the hypochlorous acid remains constant The second 
reaction is practically instantaneous 6 Chloride can be produced by the 
electrolysis of chloiate, possibly m accordance with the equation 

4MC10 3 =3MC10 4 +MC1, 

M iepiesuitm> MI atom ol a umvalent metal The foimation ot chlondc 
is promoted by use of tempera tuie, but is almost inhibited by the 
picsenee ol i ( Inornate 7 

Potassium ehloi ite forms monoclime ciystals, 8 its melting point 
being given is 357 10 C , 9 370 C , 10 and 372 C u When a solution 
obtained by tieatment of erude Cahfoiman petroleum with coneentiated 
sulphuiic aeid aid dilution with witer is added to a solution in water 
of the ordinary tabulai potassium chloiate, and the mixture con- 

1 Goppadoiu (Jaz^Ua 1905 35 11 004 

2 Btitholot 4/w Ohim Phy^ 1875 [5] 5 *37 

3 llioinson Thetntodunitshy (Longmans 190b) 328 

1 Wallioh Zeitscfi Mcltrochem 1900 12 677 bee also this aonca Vol VI1J 

Kmbbs and Palfreeman Trans J?ataday&o( 1921 16 402 
b Compare Oechsh Zeitsch Elektrochem 1903 9 807 Bennett and Mack, 
4 we/ Elektrochem Soc 1010 29 323 

7 Kmbbs and Palfreeman loc cit 

8 Ries, Zeitsch Kryst Mm 1905, 41, 243 

9 Carpentei Ghem and Met Eng , 1921 24 569 

10 Le Chateher Butt Soc chim 1887, [2] 47, 300 

11 Carnelley, Trans Chem Soc , 1876, 29, 489 



184 03* MIXED ELASTIC 

In the 9th Vol is a letter from Mr Gough, 
containing some animadversions, which were 
followed by an appropriate reply from Dr 
Henry 

In the 8th, 9th, and 10th Volumes of Ni- 
cholson** Journal, and m the first Vol of the 
Manchester Memoirs (new series) may be 
seen some animadversions of Mr Gough, ort 
my doctrine of mixed gases, with some of 
his own opinions on the same subject Mr 
Gough conceives the atmosphere to be a 
chemical compound of gases, vapour, &c and 
he rests his belief chiefly upon the observance 
of certain hygrometncal phenomena, such as 
that air absorbs moisture from bodies in certain 
cases, and in others restores it to them, shew- 
ing that air has an affinity for water, which may 
he overcome by another more powerful one 
This opinion, as Mr Murray observes, is the 
one we ha\efrom Dr Halley , it was supported 
by Le Roy, Hamilton and Franklm, and 
might be considered as the prevailing opinion, 
till Saussure, in his celebrated Lssays on hv~ 
grometry, published in 178^, suggested that 
water was first changed into vapour, and \\ as in 
that state dissolved by the air 1 his amphibious 
theory of baussure does not seem to have gai led 
any concerts to it, though it pointed out the 
instability of the other Iinally, the theory 



POTASSIUM. 167 flj 

Scobai I has proved the reaction to take place m accordance with this ^ 

equation by measuring the velocity of formation of potassium per- | 

chlorate at 395 C, and has also demonstrated its quadnmolecular 
nature ^ 

2 Simultaneously, a ummolecular reaction occurs, potassn&a 4 
chlorate decomposing with formation of potassium chloride, and 
evolution of oxygen 

2K(10 ii -2K(l+8O i 

3 A sufficient rise in temperature initiates the decomposition of the 
potassium perchlorate, chiefly in accordance with the equation 

KC10 4 =KC1+20 2 , 

and at 445 C there is complete decomposition in the sense indicated, 2 
except for a small proportion of potassium chlorate simultaneously 
regenerated s 

The decomposition is much facilitated by the presence of certain 
oxides, such as manganese dioxide The part played by these agents 
has been the subject of considerable controversy Repeated use of the 
oxide produces no measurable diminution in its activity 4 The action 
has been suggested 5 to be entirely mechanical, and analogous to that 
of sand and other substances in promoting the ebullition of water On 
this assumption, all bodies in a fine state of division might be expected 
to exert a similar influence, a view at variance with the results of 
experiment The oxides of metals capable of yielding more than one 
oxide, such as iron, nickel, copper, and cobalt, facilitate the reaction , 
but the oxides of zinc and magnesium are without effect Probably 
higher and lower oxides of manganese are formed alternately at the 
expense of the chlorate 6 In presence of the oxide there is no apparent 
formation of potassium perchlorate, 7 the manganese dioxide inducing 
the decomposition of the chlorate into chloride and oxygen at a tern 
perature lower than that necessary for the autoxidation of the chlorate 
to perchlorate with appreciable velocity 8 

Potassium perchlorate, KC10 4 Careful heating of potassium 
chlorate causes partial autoxidation to perchlorate 

4KC10 3 =3KC10 4 +KC1 

The slight solubility of the perchlorate in dilute alcohol affoids a means 
of separating it from the chloride According to Blau and Wcmgland, 9 
the decomposition ol the ehloratc is best carried out in quaitz flasks at 
480 C without a catalyst, but when between 96 and 97 pei cent of the 
chlorate has been transformed the perchlorate begins to decompose, so 
that the change is never complete The decomposition of the pei- 
chlorate is much accelerated by the presence of traces of iron oxide, 

1 Scobai Zeitsch physikal Chem 1903 44 319 
Irankland and Dingwall Ttans Chem Soc 1887 51 279 

3 Teed Proc Chem Soc , 1885 i 105, 1886 2,141 Frankland and Dmgwall, loc cit 

4 McLeod Trans Chem Soc 1889 55 184 

5 Veley Phil Trans 1888 [A] 179 270 

6 Sodeau Trans Chem Soc 1902 81 1066 

7 Eccles, J Chem Soc 1876 29 857, Toed Trans Chem Soc , 1887, 51, 283 

8 Sodeau loc cit , compare this series, Vol VII Part I 

9 Blau and Wemgland, Zeitsch Elektrochem , 1921, 27 1 



186 <W MIXED ELASTIC FLUIDS 

Feet 

Sound moves in azotic gas JOOO per second 

. oxygen gas 9 SO - 

i , carb acid 804 

. aqueous vap 1175 

According to this table, if a strong and 
loud sound were produced 13 miles off, the 
first would be a weak impression of it brought 
by the atmosphere of aqueous vapour, in 39 
seconds , the second would be the strongest 
of all, brought by the atmosphere of azotic 
gass, m 68|- seconds, the third would be 
much inferior to the second, brought by the 
oxygenous atmosphere, in 74- seconds , the 
fourth and last brought by the carbonic acid 
atmosphere would be extremely weak m 85 
seconds Now though observation does not 
perfectly accord with the theory in this re- 
spect, it comes as near it, perhaps, as it does 
to that of the more simple constitution of the 
atmosphere which Mr Gough maintains 
Derham, who has perhaps made the greatest 
number of accurate observations on distant 
sounds, remarked that the report of a cannon 
fired at the distance of 13 miles from him, did 
not strike his ear with a single sound, but that 
it was repeated 5 or 6 times close to each other 
" The two first cracks were louder than the 



POTASSIUM. im 

by the action of potassium hydroxide on perbronuc acid, and forms 
crystals isomorphous with those of potassium perehlorate * 

Potassium hypoiodite, KOI The hypoiodite has not been isolated, 
but is formed in aqueous solution by the interaction of iodine and a 
dilute solution of potassium hydroxide 

I 2 +2KOH=KOI+KI+H a O 

The solution is employed in analysis as 1 an oxidiser, the hypoiodite being 
reduced to iodide It is unstable, one part of the hypoiodite undergoing 
ojadation at the expense of the remainder 2 

3KOI=KIO 3 +2KI 

Potassium iodate, KIO 3 The lodate is formed by the oxidation 
of potassium iodide, either electrolyticalty, or by means of potassium 
permanganate or chlorate The colourless, monochnic 3 crystals 
melt 4 at 560 C , and have a density 5 of 3 89 The heat of formation 
from the elements is given as 124 49 Cal 6 and 126 1 Cal 7 At 20 C 
the solubility is 8 1 grams per 100 grams of water, the boiling-point of 
the saturated solution being 102 C 8 A semi-hydrate has been de- 
scribed 9 On heating, potassium iodate decomposes with evolution of 
oxygen, the decomposition being facilitated by the presence of MnO 2 

When the iodate is crystallized from acid solution, a di-iodate, 
KI0 3 ,HIO 3 , is formed 10 It finds application in the determination of 
the concentration of hydrogen ions, 11 and also in volumetric analysis, 
since it reacts with potassium iodide and hydrochloric acid according 
to the equation 

KI0 3 ,HIO 3 +10KI+11HC1=11KC1+12I+6H 2 

A tn lodate, KI0 3 ,2HI0 3 , has also been prepared 10 

Potassium penodate, KIO 4 The penodate is produced by oxidizing 
a mixture of potassium iodate and hydroxide either electrolytically 
or with chlorine It ciystalhzes m quadratic pyramids, melting at 
582 C , 12 and of density 3 618 13 at 15 C At 13 C its solubility is 
66 gram per 100 grams water 13 The heat of formation from the 
elements is 107 7 Cal 14 In aqueous solution it is convcited by potassium 
iodide into the iodate 

3KIO 4 +KI=4KI0 3 

Irom an aqueous solution of the penodate and potassium hydi oxide a 
basic penodate, K 4 I 2 O 9 ,9H 2 O, crystallizes 

Potassium manganate and permanganate The methods of pic- 
n and the piopcrties of these arc given in Vol VIII 

1 Kcimmtiu J pi alt Ghent 1863 90 190 

bchwickci Aeilwh physical Chem 1895 16, 303 
* Rics Zeitwh Kryst Mm 1905, 41, 243 
4 Camel Icy and Williams Trans Chem hoc , 1880 37 125 
c OUrkc Antcr J Act , 1877 [1] 14 281 
G Ihomacn Theriochwnntoy (Longmans 1 ( )OS) 528 

7 Jteithclot Ann Chun Pl\y^ 1878 [5] 13 27 

8 Kicmcis Pogg Annalen 18 r >() 97 15 

Ditto 4nn Ohim Phys 1870 [4J 21 47 

10 Mcubuig Chem Wwkblad 1904 I 474 

11 Compare Sand Bet 1906 39 2038 

12 Carnelley and Williams Trans Chem Soc 1880 37 125 
" Barker ibid 1908 93 15 

14 Berthelot, Thermochimie Pans, 1897 i 187 



188 ON MIXED ELASTIC FLUIDS 

soon perceived it was necessary, if possible, to 
ascertain whether the atoms or ultimate par- 
ticles of the different gases are of the same 
size or volume in like circumstances of tem- 
perature and pressure By the size or volume 
of an ultimate particle, I mean in this place, 
the space it occupies in the state of a pure 
elastic fluid , in this sense the bulk of the par- 
ticle signifies the bulk of the supposed im- 
penetrable nucleus, together with that of its 
surrounding repulsive atmosphere of heat 
At the time I formed the theory of mixed 
gases, I had a confused idea, as many have, 
I suppose, at this time, that the particles of 
elastic fluids are all of the same size , that a 
given volume of oxygenous gas contains 
just as many particles as the same volume 
of hydrogenous , or if not, that we had 
no data from which the question could 
be solved But from a train of reason- 
ing, similar to that exhibited at page 71, I 
became convinced that different gases ha\e 
not their particles of the same size and that 
the following maj be adopted as a maxim, 
till some reason appears to the contrary 
namely, 

That eieiy species of pine elastic find has 
its particles globular and all of a size > but 
that no two species agiee in the sue of then 



voi 



\T 



171 



density * 2 044 The heat of formation from the dements is given as 
10276 Cal, 2 1032 Cal, 3 and 1046 Cal 4 , that from the monoxide 
and water as 49 72 Cal 5 The latent heat of fusion per mol is 1 60 
Cal 6 At 795 C the vapour-pressure is 8 mm 7 

The solubility of potassium hydroxide has beeu studied by Picker- 
ing, 8 some of his ^results being given m the appended table 



Solubility of Potasswm Hydrotwde. 

Temperature, C 40 30 20 10 10 20 30 40 50 
Grams of KOH per 100 
grams of water 612 824 879 923 992 1061 1127 1222 1369 1439 



60 70 



80 



90 100 110 120 130 140 



Temperature, 
Grams of KOH per 100 
grams of water 150 157 9 163 4 177 7 187 3 201 2 214 4 235 5 281 6 

The density of the solution saturated at 15 C is 1 536 

In chemical properties the potassium derivative resembles sodium 
hydroxide, the aqueous solution being a strong base, 9 a solution 
containing 6 7 gram-molecules of the hydroxide per litre having the 
maximum OH' concentration 10 The hydroxide readily absorbs ozone, 
the product being possibly the heptoxide, K 2 O 7 n 

Three hydrates have been isolated, the monohydrate, dihydrate, and 
tetrahydrate, melting respectively at 143 C , 35 5 C , and -32 7 C , 
the transition-point of the first and second being 32 5 C , and of the 
second and third 33 C 12 

The action of aqueous solutions of potassium hydroxide on sulphur 
is similar to that of sodium hydroxide or of concentrated ammonium 
hydroxide (pp 111 and 220) 

Potassium monosulphide, K 2 S The sulphide can be formed by 
direct union of the elements, 13 by reduction of potassium sulphate with 
hydrogen or charcoal, and by the interaction of aqueous solutions of 
potassium hydroxide and potassium hydrogen sulphide It is also pro- 
duced by the action of sulphur on a solution of excess of potassium in 
liquid ammonia 14 On evaporation of its aqueous solution in vacuum 
at low temperature, the pentahydrate 15 crystalh/cs A dihydiate and 
a dodecahydratc are also known 16 The anhydrous salt can be obtained 

1 lilhol Ann Chim Phys 1847, [3] 21,415 
do Forcrand ibid 1908 [8] 15 433 

3 ihomsen Thermochemische Untersuchungen Leipsic, 1882-1883 3 235 

4 Berthclot, Thermochimie Pans, 1897, I 178 

6 de Forciand loc Git 

b Hevesy, Zeitsch phy&ikal Chem 1910, 73, 007 

7 Jackson and J J Morgan J 2nd Eng Chem 1921, 13, 110 

8 Pickering, Trans Chem Soc , 1893, 63 908 

On the heat of neutralization by hydrochloric acid, hydrobromic acid hydnodic 
acid and nitric acid compaie Richards and Rowe, J Amer Chem Soc , 1922, 44 684 

10 Kohhausch, Wied Annalen 1879 6, 1, 145 

11 Traube Be) 1912 45 2201 

1 Piokoimg Trans Chem Soc , 1893, 63 908 

13 Rengade and Costcanu, Compt rend , 1913, 156 791 

14 Hugot, ibid , 1899, 129, 388 

15 Schone, Pogg Annalen, 1867 131, 380 

16 Bloxam, Trans Chem Soc , 1900 77, 753 , Sabatier, Ann Chim Phys 1881, [5] 
22, 22 



190 ON MIKED ELASTIC FLUIM 

being 45* above the horizontal plane, or that 
plane which passes through the centres of 
the four particles On thi account the pres- 
sure is steady and uniform throughout But 
when a measure of one gas is presented to a 
measure of another in any vessel, we have 
then a surface of elastic globular particles of 
one size in contact with an equal surface 
of particles of another in such case the 
points of contact of the heterogeneous par- 
ticles must vary all the way from 40 to 
90, an intestine motion must arise from 
this inequality, and the particles of one 
kind be propelled amongst those of the 
other The same cause which prevented the 
two elastic surfaces from r n M-uaim.ig an equi- 
librium, will alwavs subsist, the ^articles of 
one kind being from their si/c unable to apply 
properly to the other, so that no equilibrium 
can ever take place > nnngs* the heteiogcncous 
particles The intestine motion must therefore 
continue till the particles arrive at the opposite 
surface of the vessel against any point of which 
they can rest with stability, and the equilibrium 
at length is acquired when cdch gas is uni- 
formly diffused through the other In the 
open atmosphere no equilibrium can take place 
in such case till the particles have ascended so 
(ar as to be restrained by their own weight , 



POTASSIUM 173 

aqueous solution of potassium hydroxide with hydrogen sulphide, 1 
evaporating to dryness in vacuum, and eliminating the water from the 
resulting J-hydrate 2 or J-hydrate* by a current of dry hydrogen It 
can be precipitated quantitatively by adding benzene or ether to a 
solution of sodium ethoxide in absolute alcohol saturated wath hydrogen 
sulphide 4 

C 2 H 5 ONa H-HgS =NaSH+C 2 H 6 OH 

Potassium hydrogen sulphide forms white, miscroseopie cubes, 
more deliquescent than the corresponding sodium derivative The 
heat of formation from the element is given as 64 Cal , 6 and that in 
aqueous solution as 65 1 Cal 6 

Potassium sulphite, K 2 SO 3 The sulphite can be prepared by passing 
sulphur dioxide into a solution of potassium carbonate till evolution 
of carbon dioxide ceases , or by dissolving a known weight of potassium 
hydroxide in water, saturating with sulphur dioxide, and adding an 
equal weight of the hydroxide Evaporation of the solution yields 
the rhombic dihydrate, which is transformed into the anhydrous salt 
at 120 C , a white solid with heat of formation 272 6 Cal 7 A mono- 
hydrate is also known 

Potassium hydrogen sulphite, KHS0 3 The primary sulphite can be 
precipitated in monoclmic crystals by addition of alcohol to a solution 
of potassium carbonate into which excess of sulphur dioxide has been 
passed It is unstable, readily losing sulphur dioxide Its heat of 
formation in aqueous solution is 211 3 Cal 8 

Potassium pyrosulphite, K 2 S 2 5 On treatment of a hot saturated 
solution of potassium carbonate with sulphur dioxide, the pyrosulphite 
separates in monoclmic crystals, which are more stable than those of 
the primary sulphite Its heat of formation from the elements is 369 4 
Cal 8 It is employed in the prepaiation of photogiaphic devclopcis 
under the name " potassium metabisulphite " 

Potassium sulphate, K 2 SO 4 The sulphate occurs in natuie in the 
form of double salts Examples are schomte, K 2 S0 4 ,MgSO 4 ,6lL>O , 
polyhalite, K 2 SO 4 ,MgS0 4 ,2CaSO 4 ,2H 2 O , and glasente, 3K 2 SO 4 ,Na 2 SO 4 
It is a by product in the manufacture of nitric acid fiom pot is 
smm nitrate and sulphuric acid, and can also be prepaied by the 
action of sulphuric acid on potassium chloride The mini sotuces of 
potassium sulphate arc kaimte (KCl,MgSO 4 ,3H 2 O) and syKine (KC1), 
both present in the Stassfuit " Abnumsalzo " Water decomposes 
kaimte into a spiimgly soluble double sulphite of potassium ind 
magnesium, and the very soluble magnesium chloiide , i similai pio 
duct is obtained by the interaction of sylvine and ki esc rite (MgS0 4 ,IJ 2 O) 
The magnesium chloride is removed by cold witei, and the icsuluil 
double sulphate treated with excess of an aqueous solution ol potassium 
chloride 

K a S0 4 ,MgS0 4 +2KCl=2K a S0 4 +MgCl a 

1 Compaie Biltz and Wilke Dorfuit Bet , 1905, 38 1J3 

2 Schone Pogg Annakn 1867 131 380 

3 Bloxam Trans Ghem Soc , 1900, 77 753 

4 Rule tbtd 1911 99 558 

r Sabatier Ann Ghzm Phys 1881, [5] 22 22 

<J Thomson, Pogg Annalen 1870, 139 242 

7 Berthelot, Ann Ghim Phys 1884 [G] I 70 

8 Berthelot, ibid , 87 



192 OH MIXED ELASTIC FLUIDS. 

fiquid, is precisely the same as if it were the 
only gas present occupying the whole space, 
and all the rest were withdrawn 

In other respects I think the last view ac* 
cords better with the phenomena, and obviate* 
the objections which Dr Thomson has brought 
against the former, particularly m regard to 
the query, why mixed gases that are known on 
certain occasions to combine, do not always 
combine , and why any gaseous particle in its 
nascent state is more disposed to combination 
than when it has already assumed the elastic 
form It will also more clearly explain the 
reason of one gas making so powerful and 
durable a resistance to the entrance of another 

One difficulty still remains respecting va- 
pour, which neither view of the subject al- 
together removes though vapour may subsist 
in the atmosphere upon either supposition, as 
far as the temperature will admit, not being 
bubject to any more pressure than would arise 
from its own particles, were the others re- 
moved, yet it may be enquired, how does it 
rise from the surface of water subject to the 
pressure of the atmosphere * how does vapour 
which ascends with an elastic force of only 
half an inch of mercury, detach itself from 
water when it has the weight of 30 inches of 
mercury to oppose its ascent ? This difficulty 



POTASSIUM 175 

Potassium hydrogen sulphate is dimorphous, crystalhzing in the 
rhombic and also in the monoclmic system Its melting-point is given 
as 200 C ! and 210 C , 2 and its mean den^ty as 2 35 3 The heat of 
formation from the elements is recorded a$ 270 1 Cal 4 and 277 I Cal * 

The solubility in water is given in the table 

Solub^hty of Potassium Hydrogen Sulphate 

Temperature, C 20 40 100 

Grams of KHS0 4 in 100 grams of water 86 3 51 4 67 3 121 6 

The boiling-point of a solution in contact with excess of salt is 
108 C 6 The solution has a very acidic reaction On heating above the 
melting-point it is converted into the pyrosulphate 

Several other potassium hydrogen sulphates have been described 7 
Examples of such compounds are K 2 S0 4 ,BH 2 SO 4 with melting-point 
91 5 C , and KgSO^HgSC^ with melting-point 218 6 C 8 

Potassium pyrosulphate, K 2 S 2 O 7 The pyrosulphate is produced 
by heating potassium hydrogen sulphate, or by the action of sulphur 
tnoxide on the normal sulphate It forms colourless crystals, melt- 
ing 9 above 300 C, and of density 2277 The heat of formation is 
474 2 Cal 10 

Potassium persulphate, K 2 S 2 O 8 The persulphate is formed in the 
electrolysis of the primary sulphate or normal sulphate in concentrated 
solution, 11 with a current density of 5 amperes per sq cm The use of 
a diaphragm is unnecessary, and the yield is much higher when the 
electrolyte contains hydrofluoric acid The compound is also manu- 
factured bv double decomposition from ammonium persulphate Any 
excess of this salt can be eliminated 12 by crystallizing from hot water in 
presence of sufficient barium hydroxide to decompose the ammonium 
derivative The heat of formation of potassium persulphate is 454 5 
Cal , 13 and the solubility at C is 1 76 grams per 100 grams of water 14 
With concentrated sulphuric acid it forms complex derivatives con- 
taining a laige proportion of oxygen 15 It unites with hydrogen pei oxide 
to form an unstable compound, probably having the formula 
K 2 S 2 8 ,H 2 O 2 This substance decomposes spontaneously into potas- 
sium hydrogen sulphate and oxygen 16 Although it has no action on a 

1 Mitscherlich Pogg Annalen 1830 18 152 173 

2 Schultz Sellack Jahresber 1871 217 

3 Compare Schroder Dichtiqkeitsmessungen Heidelberg 1873 Claike, Constants of 
Nature 2nd ed Washington 1888 I 89 

4 Berthelot Ann Chim Phyt, 1873 [4] 29 435 

5 Thomson Thermochum^che Untersuchungen Leipsic, 1882-1883 3 230 

6 Kremers Pogg Annalen 1856, 97 15 

7 Stortenbeker Rec trav chim 1902 21 401 van Bemmelen Fevhclitift 1910 }29 
dAns Zeitech anorg Chem 1909,63 225, 1913 80 29 r ) Bcigms Antwli pliywlal 
Chem 1910 72 338 Aizaher Compt rend 1908 147 129 

8 Kendall and Landon J Amer Chem Soc 1920 42 21 H 

9 Schultz Sellack Jahresber 1871 217 

10 Berthelot Ann Chim Phys , 1873 [4] 30 442 

11 Marshall Trans Chem Soc 1891 59 771 

12 Mackenzie and Marshall ibid 1908 93 1726 

13 Berthelot Ann Chin Phys , 1892 [6] 26 538 550 

14 Marshall Trans Chem Soc 1891, 59 772 

15 Compare this series, Vol VII 

16 Friend, Trans Chem Soc, 1906, 89, 1092 



194 OH LIQUIDS. 



SECTION 3 
OH THE 

CONSTITUTION OF LIQUIDS, 

And iht Mechanical Relations betwixt Ltquid$ 
and Elastic Fluids 

A liquid or inelastic fluid may be defined 
to be a body, the parts of which yield to a 
very small impression, and are easily moved 
one upon another This definition may suffice 
for the consideration of liquids in an hy- 
drostatical sense, but not in a chemical sense 
Strictly speaking, there is no substance in- 
elastic, if heat be the cause of elasticity, all 
bodies containing it must necessarily be elastic 
but we commonly apply the word elastic to 
such fluids only as have the property of con- 
densation in a very conspicuous degree 
Water is a liquid or inelastic fluid , but if it 
is compressed by a great force, it yields a little, 
and again recovers its original bulk when the 
pressure is removed We are indebted to 
Mr Canton for a set of experiments by which 
the compressibility of several liquids is de- 
monstrated Water, he found, lost about 



POTASSIUM 177 

yield the anhydrous salt in the form of very stable white crystals, 1 
also produced by the interaction of sulphur dioxide and potassium 
hydride 2 

Potassium selemdes The monoselemde^ KaSe, is formed by the 
action of selenium on excess of potassium dissolved in kqtud am&wja t 
with excess of selenium the tetraselen^de, KgSe^, is produced 3 Each 
compound resembles the corresponding sodium derivative With 
solutions of potassium carbonate, hydrogen selenide reacts forming a 
number of hydrates of the monoselemde The heat of formation of the 
anhydrous mono-derivative is given as 79 4 Cal 4 The tnselemde has 
been isolated, 5 and Fabre has also described the pnmary setemde, 
KSeH 

Potassium selenttes Little is known of the selemtes, but a normal 
selemte, a primary selemte, and a pyroselenite have been described 6 

Potassium selenate, K 2 Se0 4 Electrolytic 6xidation of the solution 
of selemte formed by the interaction of selemous acid and potassium 
carbonate yields potassium selenate, 7 rhombic crystals 8 of density 9 
3 066 at 20 C At the same temperature its solubility is 111 grams per 
100 grams of water 10 Electrolytic oxidation of its solution acidified 
with selenic acid converts the selenate into potassium perselenate u 

Potassium tellundes The monotellunde, K 2 Te, was ongmallv pro- 
duced by Davy 12 by direct combination of the elements At 250 C 
the reaction is even more energetic than that between sodium and 
tellurium When prepared in an atmosphere of hydrogen, the product 
has a crystalline structure, and a dark iridescent-purple colour With 
water it yields a purple solution, being reprecipitated by alcohol in the 
form of small, ill defined crystals 1S 

The monotellunde and the tntellunde, K 2 Te 3 , have been prepared by 
the interaction of tellurium and a solution of potassium in liquid 
ammonia 14 

Potassium tellurate, 15 K 2 TeO 4 At 20 C the solubility of the tcllurate 
is 27 53 grams per 100 grams of water 16 

Potassium chromates The modes of preparation and an account 
of the properties of potassium chromate and dichromate are given in 
Volume VII 

Potassium nitride, K 3 N The nitride is said 17 to be foimcd by 
heating potassamide, but the statement has not been confirmed by the 

1 Bazlcn Ber 1905 38 10 r >7 German Patent No 119676 
Moissan ( 1 ompt rend 1902 135 647 

3 Hugot ibid 1899 129 299 

4 iabre 4nn Chim Phyi 1887 [6], 10 506 

Clover and Muthm inn ZeiticJi anotg Chem 1895 10 117 
f Compxit Muthminn and Schafcr Bet 1803 26 1014 

7 Mullu Hit !<)()} 36 4262 

8 For isomorphism sec p 227 

9 rutlon 7 ? /f/s Chun ttoc 1897 71 846 

10 Ltdid Ann Chim Phy* 1894 [7] 2 550 compare Tutton lor nt 

11 Dennis and Blown J Amer Chem Soc 1901 23 558 
1 Davy Phil Ttans 1810 27 16 

13 Tibbals / Amtr Chem Soc 1909 31 902 

14 Hugot Compt rend 1800 129 388 

15 On potassium tellunte, compare Lenher and Wolensky, J Amer Chem Soc 1913 
35 718 

10 Rosenheim and Wemheber, Zeitsch anorg Chem 1911 69 261 
1 Gay T ussac and The nard Recherche? physico chirmqiie? 1811, I i37 Ba\y Plnl 
Tran* 1800 40 150 

VOL II 12 



196 Oil LIQUIDS 

even here we perceive the attractive force to 
prevail, there being a manifest cohesion of the 
particles Whence does this arise ? It should 
seem that when two particles of steam coalesce 
to form water, they take their station so as to 
effect a perfect equilibrium between the two 
opposite powers , but if any foreign force in- 
tervene, so as to separate the two molecules 
an evanescent space, the repulsion decreases 
faster than the attraction, and consequently 
this last acquires a superiority or excess, which 
the foreign force has to overcome If this 
were not the case, why do they at first, or 
upon the formation of water, pass from the 
greater to the less distance ? 

With regard to the collocation and arrange- 
ment of particles in an aggregate of water or 
any other liquid, I have already observed 
(page 139) that this is not, in all probability, 
the same as in air It seems highly improbable 
from the phenomena of the expansion of 
liquids by hear The law of expansion is 
unaccountable for, if we confine liquids to 
one and the same anangtment of their ultimate 
particles in all temperatures, for, we cannot 
avoid concluding, if that were the case, 
the expansion would go on in a progressive 
way with the heat, like as in air , and there 




POTASSIUM 



nitrogen If the mixed gases are passed through a solution of an 
alkali-metal hydroxide, pure nitric oxide i isolated For laboratory 
purposes this method affords a convenient means of preparing the 
gas, 10 grams of potassium nitrite producing about 2 5 litres of the 
oxide 

Potassium nitrate, KNO 3 The nitrate is manttfactured from natural 
saltpetre earths found in Bengal, and to a less extent in Egypt and 
elsewhere The nitrate in these earths is produced by the osqdatton of 
organic matter by the action of " nitrifying " bacteria in presence of 
atmospheric oxygen, a warm, moist climate hemg particularly favourable 
for the process The nitrate is extracted by lixiviating the earth in 
vessels of earthenware or wood, and cencentratmg the aqueous solution 
in iron pots by solar or artificial heat 

Artificial saltpetre earths can be prepared by allowing stable refuse 
to nitrify in contact with a porous soil containing calcium carbonate, 
the nitrate being isolated by hxiviation and purified by crystallization 
The salt is also manufactured from sodium nitrate by the action of 
potassium chloride, since it crystallizes out from a hot concentrated 
solution of these two substances as the temperature falls When 
prepared from Chile saltpetre, it often contains sodium nitrate, and 
chloride, chlorate, and perchlorate of potassium 

The extraordinary demand for nitric acid and nitrates brought about 
by the abnormal conditions consequent on the great European War of 
1914 and succeeding years gave a powerful impetus to the develop- 
ment of synthetic methods for the fixation of atmospheric nitrogen 
For an account of these developments reference should be made to 
Volume VI of this series 

At ordinary temperature, potassium nitrate crystallizes in the 
rhombic system, at higher temperatures the crystals foimed are rhombo- 
hedral The transition-point is 129 5 C x The second form is said 2 
to exist in two modifications, a and j8 Among the values given for the 
melting point arc 333 C , 3 334 5 C , 4 and 339 C 5 , for that of the 
rhombohedral form 334 C 6 For the density the mean value is given 
as 2 092, 7 other determinations giving 2 1047, 8 2 109 9 at 16 C , 2 109 10 
at 20 C , and 2 014 OOOGtf n at tcmpcratuies ranging from 350 to 
500 C The he it of formation from the elements is given as 119 Cal 12 
and 119 5 Cal 13 Ihc molecular electric conductivity of potassium 
nitrate between 340 1 and 500 4 C is given by the formula u 

^=36 21+0 1875(2-350) 

1 van Fyck Zatsch pjiynkal Cham 1905 51 721 
Walk i tint rottipl rend 1905 140 264 1000 142 100 168 

3 I nun? I<r<i and 1 ibs Zeittrli physical Chew IOOS 61 408 

4 Sttin ibid L909 65 007 Haigh / Amn Chew hoc 1912 34 1 157 
vinliycl lor tit Puson Ann Chviti Phys 1847 [3| 21 29 r > Cunelley 

Cliem *Sor 1878 33 27* 

' Roo/cboom Pro? K Alad Wetcnsch Amsterdam 1902 4, 374 

7 Oompuo Hailu Constant 1 * of Nature 2nd ed , Washington 188S I 109 and 110 

8 Andicao Zdtsdi physical Chem 1913, 82, 109 

9 Kotgus ibid 1889 3 289 

10 Haigh loc cit 

11 Jorenz Era and Jabs loc cit 

1 Borthelot Thermochitnie Pans 1897 I 193 

13 Thomsen Thermochennsche Untersuchungen Leipsic, 1882-1883 3 236 

14 Jaeger and Kapma, Zeitscli anorq Chem , 1920, 113, 27 



BftmrAL ACTION OF 

ware, or gases, in regard to their power of 
confining clastic fluids? Do they treat all 
gases alike, or do they con6ne some, and 
transmit others ? These are important questions, 
they are not to be answered in a moment 
We must patiently examine the facts 

Btefore we can proceed, it will be necessary 
to lay down a rule, if possible, by which to 
distinguish the chemical from the mechanical 
action of a liquid upon an elastic fluid I 
think the following cannot well be objected 
to When an elastic fluid is kept in contact 
with a liquid^ if any change is perceived, either 
in the elasticity or any other property of the 
elastic fluid, so far the mutual action must be 
pronounced CHEMICAL but if NO change is 
peiceived, eithei in the elasticity or any other 
pi ope? ty of the elastic fluid, then the mutual 
action of the tivo must be piorounced wholly 

MECHANICAL 

If a quantity of lime bt kept in water and 
agitated, upon standing a sufficient tuiu, the 
lime falls down, and leaves the water trans- 
parent but the water takes a sm ill portion of 
of the lime which it permanently retains con- 
trary to the Laws ot specific grivitv M hy ? 
Because that portion of him js di, solved by 
the water If a quantify of air b pjt to vvatcr 



POTASSIUM. 181 

Potassium phosphides Phosphine reacts with a solution of potassium 
in liquefied ammonia to form potassijmi fyhydropfiosphide, KH 2 P, white 
crystals decomposed by mozst air with e\olution of phosphine x On 
heating, it is converted mto twpotas&ium phosphide, K^P A solution 
of potassium in liquefied ammonia reacts with red phosphorus to form 
potasMum pentaphospkide, KP 5 2 The black product formed from 
potassium and phosphorus loses its excess of metal in vacuum at 400 
to 450 C , yielding dipotassium pentaphosphide, K 2 P 6 It is a lemon- 
yellow substance with a density of about 2, is unstable in air, and is 
decomposed by water with formation of solid phosphorus hydride 3 

Potassium hypophosphite, KH 2 PO 2 The hypophosphite is formed 
by the action of phosphorus on alcoholic potash It resembles the 
corresponding sodium derivative 

Potassium phosphites and hypophosphates Monopotassmm and 
d^potass^um hydrogen phosph^te ) potass^um pyrophosphite, and potassium 
hypophosphate are obtained by methods analogous to those employed 
for the corresponding sodium salts 

Potassium orthophosphates The normal salt, potassium ortho- 
phosphate, K 3 PO 4 , is obtained by heating basic slag or native calcium 
phosphate with charcoal and potassium sulphate The potassium 
sulphide simultaneously formed is converted mto phosphate by addition 
of phosphoric acid, or the potassium phosphate is precipitated by addition 
of alcohol The aqueous solution of the salt is very alkaline in reaction, 
owing to hydrolytic dissociation The heat of formation from the 
elements in solution is 483 6 Cal 4 

The interaction of the calculated quantities of phosphoric acid and 
potassium carbonate in aqueous solution yields dipotassium hydrogen 
phosphate, K 2 HP0 4 It is only known in solution, and in this form has 
a slightly alkaline reaction to litmus, but is neutral to phenolphthalem 
Its heat of formation in aqueous solution is 429 2 Cal 4 

Calcium phosphate reacts with potassium hydrogen sulphate and 
sulphuric acid to form potassium dihydrogen phosphate, KH 2 P0 4 , the 
most important of the potassium phosphates It forms doubly re- 
fracting crystals melting at 96 C , of density 2 3325 6 at 9 2 C , and 
2338 7 at 20 C, and of specific heat 0208 between 17 and 48 C 8 
The heat of formation in aqueous solution is 374 4 Cal 9 When heated 
at 244 C , it loses water, yielding the acid pyrophosphate, K 2 H 2 P 2 7 10 

Potassium pyrophosphate, K 4 P 2 O 7 Ihe pyrophosphate is produced 
by heating dipotassium hydrogen phosphate, 01 by ncutializmg an 
hydious phosphoric aeid with potassium hy dioxide dissolved 111 absolute 
alcohol Its specific heat is 1910 between 17 and 98 C n It is soluble 
in water, forming a slightly alkaline solution, and yields a trihydiate 

Potassium metaphosphates In mode of foimation and ehaiacter the 

1 Joanms Compt tend 1894 119, 557 

Hugot ibid 1895, 121 206 
J Haokspill and Bussuet ibid 1912 154 209 
4 Buthclot Thermochimie Pans, 1897 I 193 

lildon Trans Chem /Soc 1884 45 2bb 
tt Muthmann Zeitsch Kryst Mm 1894 22 497 
7 Kiickmcyer Zeitsch physikal Chem 189b 21, 53 
Kopp, Annalen Suppl , 1864-5, 3, i , 289 
9 Berthelot loc cit 

10 Balaieff, Zeitsch anorg Chem 1921 118 123 

11 Regnault, Pogg Annalen, 1841, 53, 60 243 



200 MtTTTTAL ACTION OP FLUIDS, 

to be retained by the attraction of the water } 
in the second case, the water seemed indiffer* 
ent ; m the third, it appears as if repulsive to 
the air , yet in all three, it is the same air that 
has to act on the same water From these 
facts, there seems reason then for maintaining 
three opinions on the subject of the mutual 
action of air and water , namely, that water 
attracts air, that water does not attract it, and 
that water repels air One of these must be 
true , but we must not decide hastily Dr 
Priestley once imagined) that the clay of a 
porous earthen retort, when red hot, " destroys 
for a time the aerial form of whatever air is 
exposed to the outside of it , which aerial 
form it recovers, after it has been transmitted 
in combination from one part of the clay to 
another, till it has reached the inside of the 
retort " But he soon discarded so extravagant 
an opinion 

From the recent experiments of Dr Henry, 
with those of my own, there appears reason 
to conclude, that a given volume of water 
absorbs the following parts of its bulk of the 
several gases 



POTASSIUM 183 

Potassium carbonate is also manufactured from the spent wash of the 
spint-disrfciller, and from the residual liquor of the wool-scourer 

Potassium carbonate is a white solid Its melting-point is given by 
various expenmenters as 878 6 C * 880 C , 2 885 C , 3 873 1 C > 
8875 C, 891 C, 4 894 C > 5 897 S C, $977 C , 6 900 C* For 
the density the mean value is given 8 as 229, a more recent deter- 
mination 9 gives 2 3312 at 17 C Its specific heat is 206 between 
17 and 47 C , 10 and 2162 between 23 axxd 99 C u At 970 C the 
vapour-pressure is 1 68 mm , and at 1130 C it is 5 mm w The heat 
of formation from the elements is recorded as 275 37 Cal , 278 8 Cal , 14 
and 281 1 Cal 15 Potassium carbonate exhibits diamagnetasm 

Several hydrates have been described, but their constitutions are 
not definitely settled 16 At 25 C the solubility is 113 5 grams per 100 
grams of water^ 8 and at 130 C it is 196 grams 17 The aqueous solution 
has a strong alkaline reaction due to hydrolytic dissociation It forms 
various primary carbonates by interaction with atmospheric carbon 
dioxide, 18 and unites with hydrogen peroxide yielding compounds of the 
formulae K 2 CO 3 ,3H 2 O 2 and K 2 C0 3 ,2H 2 2 ,pI 2 O 19 

Potassium sodium carbonate, K 2 CO 3 ,Na 2 CO 3 ,12H 2 A double 
salt of this formula is a constituent of vegetable ashes At 35 C it 
decomposes in accordance with the equation 
3(K 2 C0 3 ,Na 2 C0 3 ,12H 2 0)=2K 2 C0 3 +K 2 C0 3 ,3Na 2 C0 3 ,10H 2 0+26H 2 

The double carbonate thus generated decomposes at a temperature of 
about 130 C 20 

Potassium hydrogen carbonate, KHC0 3 Carbon dioxide precipi- 
tates the primary carbonate from a concentrated solution of potassium 
carbonate in the form of monochmc crystals of density 21 2 17 The 
heat of formation from the elements is given as 231 63 Cal 22 and 233 3 
Cal M In dilute aqueous solution it has an alkaline reaction, owing to 
hydrolytic dissociation in accordance with the equation 
KHC0 3 +H 2 0=KOHH-H 2 0+C0 2 

1 Victor Meyei Riddle and Lamb Ber , 1893, 26, 3129 

2 Ramsay and Eumorfopoulos, Phil Mag 189b, 41 360 

3 Le Chateher Bull Soc chvn 1887 [2] 47 300 

4 Niggli J Atn&f Chem Soc 1913 35, 1693 

5 Huttner and lammann Zeitsch anory Chem , 1905 43 215 
8 McCrac, Wied Annalen 1895 55, 95 

7 Amdt Zeribch Jblelt* ochem , 1906 12, 337 

8 Compare Claiko Constants of Nature, 2nd cd Washington 1SSS I 126 bchrodei 
Dichligleitbmessiingen, Hcidtlbeig, 1873 

9 Eail of Boikclcy Proc Chem Soc 1906 22, 321 

10 Kopp 4.nnalen Suppl 1864-5 3 i 289 

11 Regnault Pogg Annalen 1841 53 60, 243 

1 Jackson and J J Moigan J hid hng Chem , 1921 13, 110 

13 delorcrand Compt rend , 1909 149 719 

14 Buthdot, Ann Clum Phy* 1875 [5] 4 111 

15 Thomson Thermocheniitche UntcrsucJmngui 1 cipsic, Ibb2-lb83 3 -30 

16 Mcyoihoffoi Lundolt, Bornstein, and Mtyerhofftr 6 fubdkn 3rd cd , Bcilm 1005,0-W 

17 Mulder ticfaikwule Rotteidam 1864 97 

18 dcloiciand Co nipt rend 1909 149,719 825 

19 Kazane&ky J Euss Phys Chem Soc 1902 34, 388 

Bam and Ohvei Tian& Roy Soc Canada 1910 [3] 10 65 

1 Compare ^ik G) Constants of Nature, 2nd ed , Washington, 1888 I 129 Schiodei 
Dbchtigkeitsmessungen Heidelberg 1873 

22 de Forcrand loc cit 

23 Berthelot, loc cit 



202 MUTUAL ACTION O* FLUIDS 

circumstances , the experiments of Dr Henry 
have decided this point, by ascertaining, that 
if the exterior gas is condensed or rarefied in 
any degree, the gas absorbed is condensed or 
rarefied m the same degree , so that the pro- 
portions absorbed given above are absolute 

One remarkable fact, which has been hinted 
at is, that no one gas is capable of retaining 
another in water , it escapes, not indeed in- 
stantly, like as in a vacuum, but gradually, like 
as carbonic acid escapes into the atmosphere 
from the bottom of a cavity communicating 
with it 

It remains now to decide whether the re- 
lation between water and the abovementioned 
gases is of a chemical or mechanical nature 
From the facts just stated, it appears evident 
that the elasticity of carbonic acid and the 
other two gases of the first class 15 not at all 
affected by the vvater It remains exactly of 
the same energy whether the water is present or 
absent All the other properties of those gases 
continue just the same, as far as 1 know, 
whether they are alone or blended with water 
we must therefore, I conceive, if we abide by 
the Law just laid down, pronounce the mutual 
action between these gases and water to be 
mechanical 

A very curious and instructive phenomenon 



POTASSIUM. 185 

ferrocyamde and potassium carbonate with the s&me -reagent The 
colourless, deliquescent crystals melt 1 at 161 2 or 172 3 C , their 
density being 1 886 2 At 430 C the salt develops a Hue colour, but 
becomes white again on cooling The heat of formation from the 
elements is 50 5 Cal , 3 and at 20 C the solubility 4 is 217 grajns per 100 
grams of water Sulphur dioxide reacts with it in aqueous solution 
to form a complex derivative 5 Sodium hypobromite reacts energeti- 
cally with potassium thiocyanate, evolving heat and forming potassium 
cyanate and sulphate 6 

Potassium ferrocyamde and femcyamde The modes of preparation 
and the properties of potassium ferrocyamde, of potassium ferncyamde, 
and of similar salts are described in Vol IX , Part II 

Potassium silicates Potash water-glass is prepared similarly to the 
corresponding sodium product When the calculated proportion of 
potassium hydroxide and silicic acid is employed, addition of alcohol 
to the solution precipitates potassium metasilicate, K 2 SiO 8 When kept 
for a prolonged period over sulphuric acid, the syrup-like potash water- 
glass deposits hygroscopic plates, probably K 4 SiO 4 ,2KOH,8H 2 O 7 

Niggh 8 has demonstrated that on fusion of potassium carbonate and 
silica an equilibrium between the disihcate (see below) formed and the 
carbonate is attained 

K 2 C0 3 +K 2 Si 2 5 ^: 2K 2 Si0 3 +C0 2 

With rise of temperature the proportion of metasilicate increases 

By heating mixtures of water and finely powdered glasses at high 
temperatures, Morey and Fenner 9 have prepared potassium hydrogen 
disihcate, KHSi a O 5 , in the form of orthorhombic crystals which do 
not lose water even at 350 C , and potassium disilicate, K 2 Si 2 Q5, 
a hygroscopic salt readily acted upon by water, and melting at 
101510 C 8 

Potassium fluosilicate, K 2 SiF 6 The fluosilicate is precipitated in the 
form of microscopic crystals of slight solubility by the action of fluosilicic 
acid on solutions of potassium salts 

H 2 SiF 6 + 2KC1 = K a SiF e + 2HC1 

It is decomposed by alkali metal hydroxides with foimation of a 
fluoride and silieie acid, and can be estimated by this method with 
phenolphthalein as indicator 

4KOH+K 2 Sil 6 ==CKl +H 4 SiO 4 
Potassium hypoborate, KH 3 OB The hypoborate is a veiy deh- 

1 I'ohl, tiitzungsbcr K A Lad Wiss Wien, 1851, 6, 587 Patein6 and Mazzucckelli 
Atti J! Accad Lincei, 1907, |5], 16, i 465 

Bode kor, Jahresber ,1860 17 
Joaiims Ann ('hint Phyi 1882 [5J 26 482 

4 Rudoif I Poyy Iririalcn 1872, 145 611, compaic H W look Amei Chcm J 
190 J 30, 330 

Waldcn Bu 1899 32 2862, lox Jeitsch pliysikal Chcm 1902 41 45h Walden 
and Ccntncibzwci ibid 190 i 42 456 Smits ibid , 1905 51 193 

6 Dehn J Amet Chtm /S r oc 1909 31 1220 

7 Joidia Zeitsch anoig Chcm 1908 58 98 

8 Niggh J Amer Chem Soc 1913 35 1693 

9 Moroy and Fenner, ibid , 1914, 36 215 



204 MUTUAL ACTION OF FLUIDS 

whatever does it appear that the elasticity of 
any of these gases is affected , if water takes 
^ of its bulk of any gas, the gas so absorbed, 
exerts -zV of the elasticity, that the exterior 
gas does, and of course it escapes from the 
water when the pressure is withdrawn from 
its surface, or when a foreign one is induced, 
against which it is not a proper match As 
far as u> known too, all the other properties ot 
the gases continue the same , thus, if water 
containing oxygenous gas be admitted to 
nitrous gas, the union of the two gases is 
certain, after which the water takes up ^ r 
of its bulk of nitrous gas, as it would have 
done, if this circumstance had not occurred 
It seems clear then that the relation is a mecha- 
nical one * 

* Dr Thomson and Mr Murray have both written 
largely in defence of the notion that all gi^t s lie combined 
with water, that a real union by mi ins of a chemical 
Affinity which water exeicises 111 a greater or less degree 
towards all gases, takes place , this -\ifinity \^ supj oscd to 
be of the slight kind, orot that kind \\hich holds all ^sis 
ma state of solution, one amongst inothu, without iny 
distinction The opppo<*ite doctrine v\is in>t stited in i 
paper of mine, on the adoption of g-\s<s by \\ itt r 
(Manch Memoirs, new series, Vol 1 ) Pieviously to the 
publication of that papei, Di Henr}, who tiis convinced 
from his own expenence, tint the connection of ^ists 
flith water was of a mechanical nature, wrote Uo ebbiv* m 



POTASSIUM 187 

The test serves to identify potassium in presence of sodium The metal 
is detected and estimated quantitatively by precipitation with chloro- 
platimc acid as potassium chloroplatinate, K 2 PtQ 6 , or by conversion 
into perchlorate The insolubility of these salts in alcohol facilitates 
the separation of potassium from sodium 1 Acetone has the advantage 
of dissolving both chloroplatimc acid and sodium chloroplatinate, but 
not the potassium salt 2 The metal is also estimated as sulphate, 
chloride, primary tartrate, 3 and cobaltimtnte 4 

1 Morozewicz, Bull Acad /Set Cracow, 1906, 796 

2 Meillere, J Pharm Chim , 1913, [7], 7, 281 

8 Compare Marshall Chem Zett , 1914, 38, 585, 615 

4 Compare Mitsoherhch and Fischer, Landw Versuchs JStat , 1912, 78, 75 , van den 
Bos, Chem Weekblad 1913, 10, 182, McDougaU, J Amer Chem Soc 1912 34, 1684, 
Burgess and Kamm, ibid , 652 , Zaleski, Landw Versucha JStat , 1913, 83 221 On the 
separation of potassium from rubidium and caesium, compare Wernadski, JButt Soc fran$ 
Mm , 1913, 36, 258 



206 MUTUAL ACTION OF FLUIDS 

butes to support the incumbent atmosphere 
Finally, the gas gets completely diffused 
through the water, so as to be of the same 
density within as without , the gas within the 
water then presses on the containing vessel 
only, and reacts upon the incumbent gas 
The water then sustains no pressure either 
from the gas within or without In olefiart 
gas the surface of the water supports \ of 
the pressure, in oxygenous, &c \\> and in 
hydrogenous, &c |4 
When an) gas is confined m a vessel over 



mechanical, and those where the exertion of affinity must 
be allowed to operate " I conceive nothing is more easy 
than to point out the exact line of distinction wherever 
uater is found to dimmish 01 destroy the elasticity of any gas, 
il is a chemical agent , uherever it docs neither of these, it 
is a mechanical agent Whoever undei takes to maintain 
the chemical theoiy of the absorption of gases hv water, 
should in the outset o\e turn the following argument pre- 
ferred by Dr Hcurv " The quantity of cveiy gas 
absorbed by water, follows exactly the ratio of the pres- 
sure, and since it is a rule in philosophizing, that tfttets 
qf the same kind, though differing in degree, are pro- 
duced by the sirae cau^e, it is perfectly s\fe to conclude, 
that even, even the minutest portion of any gas, in a 
state of absorption by water, is retained entirely by incum- 
bent presbure There is no occasion, tlureioie, to call in 
the aid of the hw of chennc il affinity, when a me- 
chanical law fully and satufactoiily explains the ap- 
pearance* " 



*H 




RTJBEDIUM. 1S9 

3 Its melting point is given as 37 C ,* 37 8 9 C , 2 88 C , s 88 5 C , 4 
and 39 C f and its boiling-point as 690 C at 7@0 mm pressure, 6 the 
vapour being greenish-blue in colour At 180 C the vapour jtes a 
purple-red colour, which changes to orange above 350 C 7 Its density 
is given as 1 52 (Bunsen and Kirchhoff 8 ), 1 2$8 at 0* C (Haekspill & ), 

1 522 at 15 C (Erdmann and Kothner *>}, and 1 532 at 20 C (Richards 
and Brink 11 ) The table on p 2 indicates that in mdfmir point ,ui<l 
density rubidium, and caesium are more closely related to one another 
than to the other alkali-metals, and a similar resemblance has been 
observed regarding the crystallography of the salts of the two metals 12 
According to Rengade, 1S the specific heat of the solid at its melting- 
point is 019, and the heat of fusion ppr gram is 00615 Cal 

Several rubidium salts exhibit radioactivity, 14 among them the 
sulphate, 15 chloride, and chlorate 16 The action of the sulphate on the 
photographic plate is more powerful than that of potassium sulphate 17 

Chemical Properties In its chemical character rubidium occupies 
a position intermediate between potassium and caesium It combines 
with atmospheric oxygen and decomposes water more energetically 
than potassium, and the bright metal ignites spontaneously in dry 
oxygen It begins to react with ice at 108 C, 18 When dissolved 
in liquid ammonia, the metal combines with ozone 19 Some of its salts 
are poisonous 

Rubidium Ion The umvalent metal yields umvalent ions, analogous 
to those of potassium, but has a greater electroaffinity, its salts being 
more readily ionized This property manifests itself m the large heat 
of lonization, 20 62 6 Cal , in the ready solubility of most of its salts, and 
in the comparatively slight tendency to form complex molecules 21 
Only salts with strong amons, such as C10 3 ' 5 C10 4 ' 9 NO 3 ', A1(SO 4 ) 2 / , and 
PtCl 6 ", exhibit slight solubility 

Atomic Weight Like the other alkali metals, rubidium is umvalent, 
forming compounds of the type RbX, so that its hydrogen equivalent 

1 Guntz and Bromewski, J Chim phys , 1909, 7 464 

2 Eckardt Ann Physik 1900, I 790 

3 Guertler and Piram, Zeitsch Metallkunde 1919, n 1 

4 Bunsen and Kirchhoff Pogg Annalen, 1861, 113, 373 Erdminn and Kothner 
Annalen 1897, 294, 56 

5 Rengade Compt rend , 1913 156 1897 Butt Soc chim 1914 [4] 15 130 
Ruff and Johannsen Ber 1905 38, 3601 

7 Dunoyer Le Radium 1912 9 218 

8 Bunsen and Kirchhoff loc cit 

9 Hackspill Compt rend 1911, 152, 259 

10 Erdmann and Kothner loc cit 

11 Richards and Brink / Amer Chem Soc 1907 29 117 

12 lutton Trans Chcm Soc 1897 71, 846 ZettwJi Krijst Min 1803 29 124 
Sachs ibid 190S 38 496, Marshall J Amer Chew /Jfor 1 ( )()() 22 4S 

13 Rengade Butt Soc chim 1914 [4] 15 130 

14 Hahn and Rothcnbach, Physilcal ZeitscJi 1910 20 194 
1 Campbell Proc Camb Phil Soc 1909 15 11 

1G Strong Amer Chem J 1909 42 147 

17 Buchner Proc K Akad Wetensch Amsterdam, 1909 18 91 compare Ehter and 
Geitel, Physical Ze*foc7& , 1910, n, 275 Hennot Le Radium, 1910 7 40, Covnpt rend, 
1911, 152, 851 

18 Hackspill and Bossuet Compt rend , 1911 152 874 

19 Compare sodium p 86 

Ostwald, Orundnss der allgem Chem 3rd cd , Leipsic, 1899 281 
21 Compare Abegg and Bodlander Zeitscli anorg Chem 1899 20 462 Erdmann, 
Arch Pharm , 1894 232 25 



208 ON TOE CONSTITUTION OF SOLIDS 

much more permeable to some gases than to 
others Other liquids have not been sufficiently 
examined in this respect 

The n*utual action of water, and the greater 
numbe r of acid gases and alkaline gas partaking 
most evidently of a chemical nnture, will be 
best considered under the heads ot the respective 
icids and alkalis 



SECTION 4 

ON THE 

CONSIITUT1ON OF SOLIDS 

A solid body is one, the particles of which 
are in a stat<- of equilibrium betwixt tv\o 
great powers, t nction and repulsion, but 
in sue 1 ? manner, that no change can be 
made in their distances \\ithout considerable 
force If an approximation of the particles 
is attemp f ed by force, then the heat resists it , 
it a separation, then the attraction resists it 
I he notion of Boscovich of alternating planes 
of attraction and repulsion seems unnecessary, 
except that upon forcibly breaking the co- 
he^ionof any body, the neuly exposed surface 
must receive such a modification in its atmo- 



RUBIDIUM 191 

atmosphere of hydrogen at 650 C for five days 1 It is a white, crystal- 
line substance, 2 with density about 2 The vapour-tension fox each tem- 
perature-interval of 10 between 350 and 450 C corresponds with the 
values 100, 114, 130, 1TO 200, 253, 322, 424, and 567 mm respectively 
A possible source of error may be the presence of carbon dioxide as the 
result of decomposition of the magnesium carbonate formed , but 
soda-lime was employed to absorb any carbon dioxide liberated, and the 
measurements were made rapidly l The tension increases rapidly to 
85 mm at 230 C , and then slowly to 100 mm at 370 C 

This hydride is more stable than that of caesium, but less stable 
than that of sodium or of potassium 2 It is very reactive W&en 
heated in vacuum at 300 C it decomposes into its constituent elements 
At ordinary temperatures it is attacked by the halogens Carbon 
dioxide converts it into rubidium formate 

RbH+C0 2 =HCOORb 

Under reduced pressure sulphur dioxide converts it into rubidium 
hyposulphite, Rb 2 S 2 4 

Rubidium fluoride, RbF The fluoride is obtained in anhydrous 
crystals by concentrating a solution of sodium carbonate neutralized 
with hydrofluoric acid 3 Its melting-point is given as 753 C 4 and 
775 C 5 The boiling-point is 1410 C , and the vapour-pressure m 
atmospheres is given by the expression 6 

log p = -40000/4 57T+5 243 

It is very soluble in water, its heat of solution 7 being 5 80 Cal Two 
hydrates are known, 8 2RbF,3H 2 O, which melts at 36 C , and RbF,3H 2 O 
They are very hygroscopic With hydrogen fluoride the fluoride yields 
the primary salt RbF,HF Other acid fluorides, RbF,2HF, and 
RbF,3HF, have also been prepared 

Rubidium chloride, RbCl The chloride is produced by the inter- 
action of hydrochloric acid and rubidium carbonate, and also by heating 
rubidium chloroplatmatc It forms lustrous cubes, stated to melt at 
710 C , 9 712 to 713 C , 10 713 C , n 714 C , 12 717 C , 13 and 726 C , 14 
and to boil at 1383 C 15 The vapour-pressure m atmospheres is given 
by the expression 15 

log p = -37800/4 57T+4 998 

1 Fphraim and Michel Helv Chim Ada 1921, 4 7G2 

2 Elster and Gcitol Phyaikal Zeitsch 1910 II 257 

3 Fggc Img and Julius Meyer Zeittch anorg Chem 1905 46 174 

4 CHrnelhy Tran? Clicm 8oc 1808 33 273 

5 \\ _ and Rch ul7 ZeiM Elcktrochem 1921 27 5G8 compare Albrecht and 
\A i i i_ ibid 162 

U i i i'n and Schulz loc cit 

7 de l<oiciand Compt rend 1911 152,2? 

8 de Forcrand, ibid 1208 

9 Carnelley loc cit 

10 Huttner and Tammann Zeitsch anorg Chem 1905 43 215 

11 Haigh J Amer Chem Soc 1912 34 1137 

12 Richards and Meldrum ibid 1917 39 1816 

13 Wartenberg and Schul? Zeitsch Elektrochem 1921 27 568 compare Albiecht and 
Wartenberg ibid 162 

14 Schemtschushny and Rambach, J Russ Phys Chem Soc , 1909 41 1785 

15 Wartenberg and Schulz, loc cit 



210 ON THE CONSTITUTION OF SOLIDS. 



Lead 


.. .. 291 


Tin .. .- 


. ... 494 




2994 




360 


Sil er 


S70 




450- 


Gold 


.. . 50O 



Pounds 



A piece of good oak, an inch square and a 
yard 1 ng, will just bear in the middle SSOlbs 
But such a piece of u ood should not in prac- 
tice be trusted, for any length of time, with 
above 4 or ^ of that weight Iron is about 
10 times as strong as oak, of the same di- 
mens ons 

One would be apt to suppose that strength 
and hardness ought to be found p r o^or- 
tioriate to each other , but this is not the case 
Glass is harder than iron, yet the latter is much 
the stronger of the t * o 

Crystallization < xhibits to us the effects of 
the natural arrangement of the ultimate par- 
tteles of various co npound bodies , but we 
are sea cely yet sufficiently acquainted with 
chemical synihfcs b and analysis to understand 
the rationale ot this process The rhomboidal 
form may arise from the proper position of 
4, 6, 8 or 9 globular particles, the cubic form 
from 8 particks, the triangular form from 3, 



RUBIDIUM 193 

cubes, its melting-point being give as 641 5 C. 1 and 642 C 2 The 
boilm<jr-poml is 1305 C , 3 and the vapour-pressure in atmospheres is 
given by the expression 3 

log p = -3TOOO/4 57T+5 148 

Its density is stated to be 3 023, 4 3 447, 5 3 428 6 at 24 3 C , and 3 438 7 
at 25 C At 17 4 C its solubility is 152 grams in 100 grams of water,* 
the heat of solution being 6~5 Cal Polyiod&des such as Rblg, 10 RbI 7 , 
and RbI 9 n have been isolated 

Rubidium chlorate, RbC10 3 The chlorate is obtained by the inter- 
action of rubidium sulphate and banum chlorate On heating, it 
decomposes like potassium chlorate It is less soluble in water than the 
corresponding potassium salt, the solubility at 19 C being 5 1 grams in 
100 grams of water 12 

Rubidium perchlorate, RbC10 4 When rubidium chlorate is heated 
to a moderate temperature, it is converted into a mixture of perchlorate 
and chloride The perchlorate is isomorphous with the corresponding 
potassium salt, but is less soluble in water, the solubility at 21 3 C 
being 1 09 grams in 100 grams of water 13 

Rubidium iodate, RbIO 3 lodic anhydride reacts with rubidium 
carbonate to form the iodate, and the salt is also produced by passing 
chlorine into a hot concentrated solution of rubidium iodide and 
hydroxide 14 It forms monoclimc crystals isomorphous with those of 
potassium iodate, and of density 4 559 at 14 C At 23 C the solubility 
is 2 1 grams in 100 grams of water 15 It yields acid iodates, lB such as 
RbI0 3 ,HIO 3 and RbIO 3 ,2HIO 3 , and also compounds of the type 
RbI0 3 ,F 2 16 and RbIO 3 ,HIO 3 ,4HF 17 

Rubidium periodate, RbI0 4 When a mixture of rubidium iodate 
and hydroxide in hot concentrated solution is oxidized with chlorine, 
the periodate is formed in colourless quadratic crystals isomorphous 
with those of potassium periodate, and with the density 3 918 at 16 C 
At 13 C its solubility is 65 gram in 100 grams of water 18 

Rubidium monoxide, Rb 2 O When rubidium is partially oxidized 
by diluted oxygen, and the excess of metal removed by distillation, the 

1 Victor Meyer Riddle, and Lamb Ber 1893 26 3129 

2 Carnelley Trans Chem Soc , 1898 33, 273 

3 Wartenberg and Schulz Zeitsch Elektrochem 1921 27,668, compare Albrecht and 
Wartenberg ibid 162 

* Compare Schroder Annalen, 1878 192, 295 
5 Lrdmann Arch Pharm 1894 232 25 
c Buchanan Proc Chem Soc 1905 21, 122 

7 Baxter and Brink J Amer Chem Soc 1908 30 46 

8 Reissig Annalen 1863 127 34 

9 de J? orcrand Compt rend 1911 152 27 

10 Wells and Wheeler Zeitsch anorg Chem 1892 I, 442 2,257, compare Foote and 
Chalkei Amer Chem J 1908 39 561 

11 Abegg and Hamburger Zeitsch anorg Chem , 1906 50, 403 
1 Reissie; loc cit 

13 Lougumme Annalen, 1862 1 21 123 

14 Barker Trans Chem Soc 1908 93 15 

15 Wheeler Amet J Sci 1902 [3] 44 123 

16 Wemland and Lauenstem Zeitsch anorg Chem 1899 20, 30 Wemland and Alfa 
ibid 1899 21 53 

17 Wemland and Koppon ibid 1900, 22 260 Wemland and Barttlmgck Bet 1903 
36, 1401 

18 Barker loc cit 

VOL II 13 



212 ON CHEMICAL SYNTHESIS, 

its dignity by keeping all the rest, which by 
their gravity, or otherwise are disposed to en- 
croach up it, at a respectful distance When 
we attempt to conceive the number of particles 
in an atmosphere, it is somewhat like attempt- 
ing to conceive the number of stars in the 
universe , we are confounded with the thought 
But if we limit the subject, by taking a given 
volume of any gas, we seem persuaded that, 
let the divisions be ever so minute, the number 
of particles must be finite , just as in a given 
space of the universe, the number of stars and 
planets cannot be infinite 

Chemical analysis and synthesis go no far- 
ther than to the separation of particles one 
from another, and to their reunion No new 
creation or destruction of matter is uithmthe 
reach of chemical agency We might as well 
attempt to introduce a new planet into the 
solar system, or to annihilate one already in 
existence, as to create or destroy a particle of 
hydrogen All the changes we can produce, 
consist in separating particles that are in a stale 
of cohesion or combination, and joining those 
that were previously at a distance 

In all chemical investigations, it has justly 
been considered an important object to ascer- 
tain the relative weights of the simples which 



RUBIDIUM 195 Jj 

microscopic white needles belonging to the eulQ system, and isomor- > 

phous with those of the corresponding salt of pot^ssium^ but not with 1 

those of caesium monosulphide Its density is 2 912, and it melts at the jj 

temperature of softening of glass It dissolves m water with a hissing 4 

sound, the heat of solution being 24 6 Cal The heat of formation of the | 

solid from its elements is 87 1 Cal ? and that from rubidium hyfcra&e ^ 

and hydrogen sulphide is 8 Cal Rubidium monosulphide is readily ^ 

oxidized, is combustible, and weathers m air x * 

The monosulphide is converted by sulphur m an atmosphere of * 

hydrogen into the pentasulphide, RbgS 6 , deliquescent, re4 crystals melt- i 

ing at 223 to 224 C , and of density 2 618 at 15 C When heated 
in nitrogen it yields the trisuLphide, RbgSg, consisting of hygroscopic, 
dark-yellow crystals melting at 213 C , but in hydrogen the hygro- 
scopic disulphide, Rb^^, is formed, a substance meltmg about 420 C 
and boiling above 950 C Both the disulphide and the tnsulphide 
yield a monohydrate The tetrasulphide, RbgS^ is formed by heating 
the monosulphide with the calculated amount of sulphur It yields 
a yellow, crystalline dihydrate Rub^d^um hydrogen sulphide^ RbSH, 
is produced by saturating a solution of rubidium hydroxide with 
hydrogen sulphide 

Rubidium sulphate, Rb 2 SO 4 The sulphate forms rhombic crystals 
isomorphous 2 with those of potassium sulphate, melting 3 at 1074 C , 
the density at 20 C being 3 6113, and at 60 C 3 5943 4 It exists in 
two modifications, 5 the transition point being 657 C The heat of 
formation from the elements is 344 68 Cal , and the heat of solution 
6 66 Cal at 15 C 6 The solubility 7 is given in the appended table 

Solubility of Rubidium Sulphate 

Temperature, C 10 20 30 40 50 60 70 80 90 100 

Grams of Rb 2 S0 4 per 

100 g of water 36 4 42 6 48 2 53 5 58 5 63 1 67 4 71 4 75 78 7 818 

The boiling point of the saturated solution in contact with excess 
of sulphate is 103 5 C at 760 mm pressure 8 With aluminium and 
ferric sulphates it forms well crystallized alums It exhibits radio- 
activity 9 

Rubidium hydrogen sulphate, RbHSO 4 The primary sulphate has 
a density at 16 C of 2 892 10 Its heat of foimation fiom the elements 
is 277 37 Cal , and its heat of solution 3 73 Cal u On ignition it is 
converted into rubidium pyrosulphate, Rb 2 S 2 O 7 

Rubidium persulphate, Rb 2 S 2 8 The persulphate is formed by the 

1 Rengade and Costearm Compt rend 1913 156,79! 1914 158 946 

2 See p 227 

3 Huttner and Tammann Zeitsch anotg Chem 1905 43 215 

4 Tutton Trans Chem Soc 1894, 65 628 1896 69 344 

5 Huttner and Tammann loc cit 

6 do Forcrand Compt rend 1906 143 98 

7 Landolt Bornstem and Meyerh offer Tabellen 3rd ed Berlin 1905 566 compare 
Earl of Berkeley Phil Trans 1904 [A], 203 207 iStard Ann Chim Phys 1894 [7] 
2 550 

8 Farl of Berkeley and Applebey Proc Roy Soc 1911 [A] 85 489 

9 Buchner Le Radium 1912 9 259 

10 Spring Bull Acad roy Belg 1904 290 

11 de Forcrand loc cit 



214 ON CHEMICAL SYNTHESIS 

The following general rules may be adopted 
as guides in all our investigations respecting 
chemical synthesis 

1st When only one combination of two 
bodies can be obtained, it must be presumed to 
be a binary one, unless some cause appear to 
the contrary 

2d When two combinations are observed, 
they must be presumed to be a binary and a 
ternary 

3d When three combinations are obtained, 
we may expect one to be a binary, and the 
other two ternary 

4th When four combinations are observed, 
we should expect one binary, two ternary, and 
one quaternary, &c 

5th A binary compound should always be 
specifically heavier than the mere mixture of its 
two ingredients 

6th A ternary compound should be speci- 
fically heavier than the mixture of a binary 
and a simple, which would, if combined, 
constitute it, &c 

7th The above rules and observations 
equally apply, when two bodies, such as 
C and D, D and E, &c are combined 

From the application of these rules, to the 
chemical facts already well ascertained, we 



RUBEDITJM. 197 

I 

interaction of rubidium sulphate and barmm hycbrazoate* 1 It forms 
tetragonal plates melting at 330 to 840 C , wiaeb display marked ] 

double refraction It is not very explosive, but melts between 330 and J 
340 C with evolution of gas The solubility at 16 C is 107 1 grams 4 
in 100 grams of water, the solution having a slightly alkaline reaction 1 

Rubidium nitrite, RbNO^ Barium nitrite and rubidium sulphate f 

interact to form rubidium nitrite, a yellowish, crystalline substance, ^ 

very soluble in water 2 

Rubidium nitrate, RbNO 3 The nitrate is tnmorphous, 3 crystalhsaaag $ 

in hexagonal, 4 cubic, and bi-refractive forms, the transition-points ** 

in the order named being 161 4 C and 218 9 to 219 3 C The 
crystals are very hard, melt at 313 C , 6 and have a density of 3 131 6 ^ 

at 15 C and 3 112 at 20 C 7 The molecular electee conductivity of 
rubidium nitrate between 318 8 and 493 C is given by the formula 8 

^=33 51+0 145(2300) 
The solubility in water 9 is given in the table 

Solubility of Rubidium Nitrate 

Temperature, C 10 20 30 40 50 60 70 80 90 100 

Grams of RbN0 3 per 

100 g of water 19 5 33 53 3 81 3 116 7 155 6 200 251 309 375 452 

A saturated solution containing 617 grams in 100 grams of water 
boils at 118 3 C under a pressure of 734 mm of mercury In chemical 
properties the salt resembles potassium nitrate It exhibits radio- 
activity 10 With nitric acid it yields acid nitrates, 11 RbNO 3 ,HN0 3 , 
melting at 62 C , and RbN0 3 ,2HN0 3 , melting at 39 to 46 C 

Rubidium phosphide, Rb 2 P 5 The phosphide is formed by the 
interaction of phosphorus and rubidium hydride, and also by Hackspill 
and Bossuet's method (p 136) In properties it resembles closely the 
corresponding potassium derivative, and has a density of 2 5 12 

Rubidium phosphates The three phosphates are prepared by the 
interaction of phosphoric acid and rubidium hydroxide or carbonate in 
appropriate proportions 13 The pi imary phosphate, RbH 2 PO 4 is acidic 
in aqueous solution , the other two are alkaline When heated at 
244 C the primary phosphate loses water, yielding the acid pyro 
phosphate, Rb 2 H 2 P 2 O 7 14 The secondary phosphate forms a monohydrate, 

I Curtms and Rissom J prakt Chem , 1898 [2] 58, 280 compare Dennis and 
Buiedikt, Zeitsch anorg Chem 1898 17 20 

Ball and Abram Trans Chem Soc 1914 103 2130 

3 Schwarz Landolt Bornstein and Meyerhoffet s Tabdlen 3rd ed Berlin 1905 283 

4 Compare Jaeger Zeitsch Kryst Mm 1907 43 588 Duff our Bull Soc franc 
Mm 1913 36 136 

Haigh J Amer Chem Soc 1912, 34 1137 
Hetgers Zeitsch physikal Chem 1889 4 597 

7 Haigh loc cit 

8 Jaeger and Kapma Zeitsch anorg Chem 1920, 113 27 

9 Earl of Berkeley Phil Trans 1904 [A] 203 207 compare Landolt Boinstun 
and Meyerhoffer Tabdlen 3rd ed , Berlin, 1905 560 

10 Buchner Le Radium 1912 9 259 

II Wells and Metzger, Amer Chem J , 1901, 26, 271 

12 Compare Bossuet and Hackspill Compt rend, 1913, 157, 720 

13 Von Berg Ber , 1901 34 4181 

14 Balareff, Zeitsch anorg Chem, 1921, 118, 123 



216 Otf CHEMICAL SYNTHESIS 

In the sequel, the facts and experiments 
from which these conclusions are derived, will 
be detailed , as well as a great variety of others 
from which are inferred the constitution and 
weight of the ultimate particles of the prmcr 
pal acids, the alkalis, the earths, the metals, 
the metallic oxides and sulphurets, the long 
tram of neutral salts, and in short, all the 
chemical compounds which have hitherto 
obtained a tolerably good analysis Several 
of the conclusions will be supported by origi- 
nal experiments 

From the novelty as well as importance of 
the ideas suggested in tins chapter, it is deemed 
expedient to give plates, exhibiting the mode 
of combination in some of the more simple 
cases A specimen of these accompanies this 
first part The elements or atoms of such 
bodies as are conceived at present to be simple, 
are denoted bv a small circle, with some dis- 
tinctive mark , and the combinations consist in 
the juxta-position of two or more of these , 
when three or more particles of elastic fluids 
are combined together in one, it is to be sup- 
posed that the particles ot the same kind repel 
each other, and therefore take their stations 
accordingly 

END OF PART THF IIRSF 



RUBIDIUM. 19 

or higher Its properties are similar to those of the corresponding 
potassium salt 1 

DETECTION AND ESTIMATION OF RUBIDIUM 

Rubidium salts impart a reddish- violet coloration to the Boosei* 
flame, similar to that characteristic of potassium derivatives like 
potassium, rubidium forms several salts not readily soluble, among them 
the chloroplatinate, perchlorate, sihcofluonde, bismuth thiosulphate, 
and primary tartrate It can also be detected by the formation of 
Bi(NO 2 *) 3 ,2RbN0 2 ,NaNO 2 , a yellow crystalline precipitate produced 
by adding a solution of bismuth nitrate and sodium nitrite to one of 
a rubidium salt 2 

Rubidium chloride yields a complex rubidium-silver-gold chloride, 
separating in blood-red prisms The formation of this precipitate is an 
aid in the microchemical identification of rubidium, and serves to detect 
one tenth of a microgram of the element 8 

The metal can be estimated as chloride or sulphate, or by heating 
the sulphate with sulphuric acid and the sulphate of an alkaline-earth 
metal such as calcium, a double sulphate of the type Rb 2 SO 4 ,CaSO 4 
being formed and weighed 4 

1 Rosenheim and Leyser, Zettsch anorg Chem , 1921, 119,! 

2 Ball, Trans Chem Soc , 1909, 95, 2126 

3 Bayer, Monatsh , 1920, 41, 223 , compare Emich, ibid , 243 

Mackenzie and Marshall, Trans Chem Soc , 1908, 93 1726 On the separation from 
sodium and potassium, compare Vernadski, Bull Soc franc, M^n , 1913, 36 258 



S al 



Vapon 



200 



Witer 



212- 



100 



- r 



TBO 



CJSSIUM. 201 

at 26 C , 1 836 at 27 C , and 1 827 1 at 40 C The-atomic volume is 
71, and is higher than that of any other element. 2 At absolute zero 
the density is 2 222, and the corresponding atomic volume us 50 77 * 
The specific heat is 04817 between and 26* C, 4 aad is given fey 
Rengade 5 as 0600 at C The heat of fusion of 1 gram is grtrea as 
3 73 cal , and also 5 as 3 76 cal It is the softest metal* the hwJness 
on Rydberg's 4 scale being 2 Neither the metal nor any of its salts 
displays radioactivity 7 

Chemical Properties In chemical properties csesium is closely 
related to potassium and rubidium When brought into contact with 
air, it undergoes rapid oxidation, and the pure metal ignites m dry 
oxygen at the ordinary temperature 8 It decomposes water energeti- 
cally, the action on ice beginning at 116 C 9 Its solution in liquid 
ammonia reacts with ozone 10 

Caesium Ion Caesium forms colourless univalent ions It is the 
most electropositive of the elements, its great electroaffimty cor- 
responding with the ready solubility of its salts The salts with strong 
amons are less soluble than the corresponding derivatives of the other 
alkali-metals 11 

Atomic Weight The chemical properties of caesium indicate its 
close relationship to the other alkali-metals It is univalent, forming 
compounds of the type CsX, its atomic weight and hydrogen equivalent 
being the same Its atomic weight is of the order Cs=133 a value 
confirmed by the specific-heat method (Vol I , p 88) , by the iso- 
morphism of the caesium compounds with those of potassium, ammonium, 
and rubidium (Vol I , p 74) , by the correspondence of the properties 
of the metal and its compounds with the periodic system , by the 
formation of a univalent cation , and by the depression of the freezing- 
point of bismuth chloride and mercuric chloride produced by caesium 
chloride 

Early Determinations 

The eaihcst determination of the atomic weight of caesium with any 
approach to accuracy was that of Johnson and Allen 12 The mean of 
foui experiments gave the value 

AgCl CsCl=100 117499, 

1 * ok irdt and Graf c Zeitsch anorg Chem 1900 23 378 

2 (Wipaie Rudorf Das Penodische System Hamburg 1904 120 

3 Herz Zeitsch anorg Chem 1921 120, 159 compare Heiz ibid 1919 105 171 , 
Loicnz and Herz ibid 1921 117 267 

4 1< c kardt \nd Grafo loc cit 

5 Rcngade Bull Soc chim 1914 [4] 15, 130 

Rydbug ZeiUcli physical Chem 1900 33 353 

7 Compare Lcvm and Rucr Physilal Zeitsch 1909 10 576 Elstci and Geitel 
ibul 1910 ii 275 Honriot Le Radium 1910 7 40 Compt tend 9 1911 152 851 
Buchner Le Radium 1912 9 259 , compare Hahn and Rothtnbach Physilal Zeitsch , 
1919 20 194 

8 Rengide Compt rend 1906 142 1533 1907, 145,236 Ann Glum P7/s , 1907 
[8] II 348 

9 Hackspill and Bossuet Compt rend 1911, 152 874 

10 Compare the section on sodium p 86 

11 Compare Abegg and Bodlander Zeitsch anorg Chem 1899 20 462 
1 Johnson and Allen Amer J Set , 1863 [2] 35 94 



218 EXPLANATION OF THE PLATES 

curve, repiesent equal intenals of temperatuu (25 
steam or aqu ous vapour, ind 34 for ethereal vapo 
the orchnates represent inches of meicuiy, the weight 
which & equal to the force of *team at the tcmnciatu 
See tht 8th and 91 h rolumns of table, at pag< 1 4 Thus 
force of steam at 212, and of ethereal vapoui at II 
new scale, is equal to 30 inches of merciny , at 187 
force of steam is half as much, or 15 inches and at 7 
that of ethereal vapoui is also 15 inches &c 

Fig 3 is a device suggested by Mi Ewart, to illustr 
the idea which I have developed in the section on the te 
perature of the atmosphere It is a cylindrical vessel cl 
at one end and open at the other, having a moveablp ] 
ton sliding within it the vessel is supposed to contain 
and a weight is connected v\ith the piston as a counter pc 
to it There is also a thermometer supposed to j 
thiough the side of the vessel, and to be cemented mU 
Now if we may suppose the piston to move with 
friction, and the vessel to be taken up into the atmosphi 
the piston will gradually ascend, and sufFei the ai** wit 
to dilate, so as to correspond oveiy v\ hue with the exte 
air in density Ihis dihiation Unds to diminish the ti 
perature of the air within (proiidecl no heat is acqui 
from the vessel ) Such an mstiumtnt uould shew w 
the theory requires, namely, that the temperature of 
air within would every where in the <-ame \uti<al colu 
agree with that without, though the foimei \\ould not 
ceiveorpart with any heat absolute!), 01 many man 
communicate with the external air 

PLATE III See page 135 The bills in li% \ an 
repiesent particles of water in the form< r the squ 
form denotes the arrangement in AiUr, the rhomho 
form in the latter, denotes the airangtnunt in ict 
angle is always 60 or 120 

Fig 3 repiesent 1 * the perpcndicuhr srction of a 
resting upon two others, as 4, \ n( \ 8, I ig I 

Fig 4 irpipsents the perpcndu nl ir M < hon of i 
resting upon two balls, as 7 and 5 ti^ 2 1 IK pnj 
diculais ot th<? triangles shew the l(iL,itsoJ the strit 
the tun anangements 

Fig 5 represents one of the snnll spicul^ of u < forr 
upon the sudden congelation of witti cooled below 
frer^iog point See pigt 13 1 

Fig 6 lepresents the shoots or ramihi itmns of i 
the com nencement of congelation Ihe nult* ire 
aid 120 



COMPOUNDS OF CAESIUM. 1 

Caesium hydride, CsH It is difficult to prepare the h\ dnde in a, state 
of purity It can be obtained in the form of white crystals by tlie 
interaction of pure caesium and pure hydrogen, its general characteristics 
being similar to those of the corresponding rubidium derivative 2 
Ephraim and Michel 8 produced it by heating a mixture of caesium 
carbonate and metallic magnesium HI hydrogen at 580 to 020 C 
for three days It is the least stable of the alkali-metal hydrides 
Its density 4 is 2 7 Ephraim and Michel 3 found the vapour tension 
for each interval of 10 between 340 and 440 C to be 78, 100, 126, 
160, 202, 256, 317, 402, 503, 630, and 787 mm , but the measure- 
ments may have been vitiated by the presence of carbon dioxide 
arising from decomposition of the magnesium carbonate formed, by 
the sublimation of the metal, and by its solubility in the hydride 

Caesium fluorides Evaporation of a solution of caesium carbonate 
in hydrofluoric acid yields the pmma%y flumde, sF,HF 5 When 
heated, this substance is converted into the normal fluonde, CsF, which 
crystallizes in cubes, melts at 684 C , 6 and boils at 1251 C 6 Its vapour- 
pressure in atmospheres corresponds with the expression 6 

log p = 34700/4 57T+4 982 

The anhydrous fluoride yields two very deliquescent hydrates, 
CsF,l 5H 2 O, and 3CsF,2H 2 7 The heat of solution of the anhydrous 
salt is 8 37 Cal 8 

Caesium chloride, CsCl The chloride is prepared similarly to that 
of rubidium It forms cubes, melting at 626 C , 9 631 C , 10 645 C , 11 
646 C 12 or 647 C , 13 and boiling at 1303 C 14 The vapour pressure m 
atmospheres is given by the expression w 

log jp = -37400/4 57T+5 190 

The substance has a density of 3 972 15 or 3 987 16 at 20 C , and 3 982 17 
at 23 1 C Its latent heat of fusion per gram is 024 Cal 18 The 

1 Attention is called to the close analogy in modes of preparation and piopeities of 
tho caesium and rubidium compounds For ccesium amalgam, see this series Vol III 

Moissan Compt rend, 1903, 136, 587 1177, Elstei and Geitel Physilal Zeitsch 
1910 II 257 

3 Lphraim and Michel Helv Chim Acta, 1921, 4, 702 

4 Moissan loc cit 

5 Chabrie" Compt retid 1901 132 680 

6 Wartenberg and Schulz Zeitsch Elektrochem , 1921 27 568 compare Albrccht and 
Waitcnberg ibid 162 

7 de Forcrand Compt rend 1911, 152 1208 

8 de Forcrand, ibid , 27 

9 Wartenberg and Schulz, Zeitsch Elektrochem 1921, 27, 568 compare Albiccht and 
Waitenberg ibid 162 

10 Camclley and Williams Trans Cham /Soc 1880 37 125 

11 Richards and Meldrum J Amer Chem Soc 1917, 39 1810 

1 bchemtschushny and Rambach J fiuss Phys Chem Hoc 1909, 41 1785 

13 Haigh J Amer Chem Soc 1912, 34 1137 

14 Wartenberg and Schulz loc cit 

15 Richards and Archibald, Zeitsch anory Chem , 1903, 34, 353 

16 Haigh, loc cit 

17 Buchanan, Proc Chem Soc , 1905 21, 122 

18 Schemtschushny and Rambach, loc cit 



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CUSTOM. 



solution is 8 25 Cal * A trwodbde and a pentawdide have been 
isolated, 2 and the existence of a heptatodade and of an enneawdtde, 
is probable 



been effected by^McCrosky and BueU, 5 and is stated to be earned out 
best m acid solution It crystallizes without water of crystaDizatioai, 
and melts at a higher temperature than potassixnn bromate* At 
30 C 100 grams of water dussolve 4 53 grams of the salt 

Caesium lodate, CsIO 3 The lodate is precipitated by the action of 
chlorine on a hot concentrated solution of caesium iodide and hydroxide 6 
It yields monochnic crystals, igoniorphous with the corresponding salts 
of rubidium and potassium, and of density 4 831 at 16 C At 24 C 
its solubility is 2 6 grams m 100 grams of water 7 

Caesium penodate, CsIO 4 Hie penodate is prepared by the action 
of caesium carbonate on, periodic acid 8 It forms orthorhombic plates, 
notisonaorphous Ai,(li | n < <ri< ^pondm^ - ilUof luhiilmm and potassium * 
It has a density of 4 250 at 15 C , and its solubility at 15 C is 2 15 
grams in 100 grams of water 

Caesium monoxide, Cs 2 O The monoxide is prepared by incomplete 
oxidation of the metal at ordinary temperature, the excess being 
removed by vacuum-distillation at 180 to 200 C 10 It forms scarlet- 
red crystals, 11 which become purple-red at a temperature above the 
ordinary, and black at 150 C At 180 C their colour is bright 
yellow The substance melts at 450 to 500 C , decomposing into 
the metal and the peroxide, Cs 2 O 2 At C it has a density of 4 36 12 
(water at C =1) Its heat of formation is 82 7 Cal , 13 and its heat of 
solution is 83 2 Cal 14 From the air it absorbs moisture and carbon 
dioxide, becoming white and deliquescent It dissolves to a clear 
solution in water, the process being attended by a hissing sound and 
the production of flame In moist carbon dioxide it ignites at the 
ordinary temperature Hydrogen reduces it to the hydride and 
hydroxide 

Caesium suboxides Two suboxides have been isolated, 15 Cs 7 O, a 
bronze coloured solid, melting at 3 C , and Cs 7 2 , long prisms of 
permanganate colour Both are formed by fusion of the monoxide 
with cxsium, the fusion curve indicating the existence of two other 
suboxides, Cs 4 and Cs 3 

Csesium peroxides Three peroxides have been picpaied by heating 

1 do lorcrand Gompt rend, 1911, 152, 27 

2 Wells and Wheeler Zeitsch anorg Chem 1892 I, 442 , 2 2o7 

3 Abegg and Hamburger ibid 1906 50 403 compare lootc Amer Chem J 1903 
29 203 Dawson and Goodson Trans Chem Soc 1904 85 796 

4 Compare Baur Zeitsch physilcal Chem 1895 18 184 

5 McCrosky and Buell J Amer Chem Soc , 1920 42 178G 

6 Barker Trans Chem Soc 1908 93 15 

7 Wheeler Amer J Sci 1902, [3] 44, 123 

8 Wells Amer Chem J 1901, 26 278 

9 Barker loc cit 

10 Rengade Compt rend 1906, 143 592 1907 144 753 

11 Rengade, ibid 1909 148 1199 Bull Soc chim 1909 [4] 5 994 

12 Rengade, Bull Soc chim 1907 [4] I 666 

13 Rengade, Compt rend 1908 146 129 de Forcrand ibid 1914 158 001 

14 Rengade, ibid , 1908 146, 129 

18 Rengade, ibid 1909 148, 1199 Bull Soc chim 1909 [4] 5 994 



220 EXPLANATION OF THE PLATES 

Enough has been given to shew the method , it will be 
qmte unnecessary to devise characters and combinations of 
them to exhibit to view in this way all the subjects that 
come under investigation , nor is it necessary to insist upon 
the accuracy of all these compounds, both in number and 
weight , the principle will be entered into more particularly 
hereafter, as far as respects the individual results It is not 
to be understood that all those aiticles marked as simple 
substances, are necessarily such by the theoiy , they are 
only necessarily of such weights Soda and Potash, such 
as they are found in combination with acids, are 28 and 42 
respectively in weight , but according to Mr Davy's very 
important discoveries, the\ are metallic oxides, the former 
then must be considered as composed of an atom of metal, 
21, and one of oxygen, 7 , and the latter, of an atom of 
metal, 35, and one ot oxygen, 7 Or, soda contains 75 
per cent metal and 25 oxygen , potash, 833 metal and 
16 7 oxygen It is particularly remarkable, that accord- 
ing to the above-mentioned gentleman** essay on the De- 
composition and Composition of the fixed alkalies, in the 
Philosophical Transactions (a copy of which essay be has 
just faroured me with) it appears that " the largest quan- 
tity of oxygen indicated by these experiments vas, for 
potash 17, and for soda, 26 parts in 100, and the smallest 
13 and 19 w 



DIRECTIONS TO THE BINDER 



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2 to face page 218 

3 to follow plate 2 

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O2ESIUM 207 

yield a montihydrate The tetrasulpfade, Cs& us anhydrous The 
penta$ulph^de > Cs 2 S 5 , melts at 204 to 205 C , and its density at 16 C 
is 2 $06 J 

Csesurat sulphites *~ The normal sulphite, Cs^Q^ *$ prepared by 
addition of an equivalent proportion of caesium carbonate to an ^leokolie 
solution of the salt saturated \pth gujphur dioxide It forms >daste 
readily soluble crystals 9 

The primary wlphite, CsHSO,, is prepared by the ac&on of sulphur 
dioxide on an alcoholic solution of the carbonate It 15 a whrte, 
crystalline salt, very soluble in water 

Caesium sulphate, CsgSC^ The sulphate is produced by the inter- 
action of caesium chloride a&d sulphuric acid 2 It forms rhombic 
crystals, 3 melting at 99 C * or 1019 C 5 Its density at 16 C is 
4260S at 20 C, 42436, and at 60 C, 42218 7 

The solubility 8 is given ni the table 

SolwMvty of C 'cesium Sulphate 

Tempearatoe, & C 10 20 30 40 50 60 70 80 90 100 
Grams of Cs^SCM 

per 100 grams [-167 1 1731 1787 1841 1894 1949 1999 2050 2103 2149 2203 

of water ) 

A saturated solution boils at 110 C at 760 mm pressure 9 The salt 
is almost insoluble in alcohol The heat of formation from the elements 
has been calculated 10 to be 349 8 Cal It forms well-crystallized double 
salts with the sulphates of lithium, ferric iron, aluminium, and bivalent 
metals 

Caesium hydrogen sulphate, CsHS0 4 The primary sulphate 
crystallizes m rhombic prisms, 11 of density 3 352 12 at 16 C Its heat 
of formation from the elements is 282 9 Cal , and its heat of solution 
3 73 Cal 13 

Another acid sulphate, Cs 2 0,8S0 3 , and the pyrosulphate, Cs 2 SO 7 , 
have been prepared u 

Caesium persulphate, Cs 2 S 2 8 The persulphate is produced by 
electrolysis of a concentrated solution of the sulphate 15 

Caesium thiosulphate, Cs 2 S 2 3 The thiosulphate is formed on 
addition of sulphur to a boiling solution of the sulphite, 16 and also by 
the action of the carbonate on barium thiosulphate 17 It crystallizes m 
small, very soluble needles 

1 Chabne Compt rend, 1901 132 680 
Foote J Amer Chem Soc 1911, 33 463 

3 For isomorphism, see p 227 

4 Muller N Jahrb Mineral Beil Bd 1914 30 1 Zeitsch Kryst Mm 1914 53 511 

5 Huttner and Tammann Zeitsch anorg Chem , 1905 43 215 
c Spring Bull Acad roy Belg 1904 290 

7 Tutton Zeitsch Kry&t Mm 1895 24 1 

8 Landolt Bornstem and Meyerhoffer Tabellen 3rd cd Berlin 1905 534 Earl of 
Berkeley Phil Trans 1904 [A] 203, 207 

9 Earl of Berkeley and Applebey Proc Roy Soc 1911 [A] 85 489 

10 de Forcrand Cornet rend 1906 143 98 

11 Bunsen and Kirchhoff Pogg Annalen 1861 113 342 1863 119 1 Annalen 1862 
122 347 , 1863 125 367 

12 Spring loc cit 13 de Forcrand loc cit 

14 Weber Ber 1884 17 2500 

15 Foster and Smith J Amer Chem Soc ,1899 21 934 

16 Chabne Compt rend 1901, 133 295 

17 Julius Meyer and Eggelmg, Ber 1907 40 1351 



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CJE&EUM. 2# 

The molecular electric conductivity of caesium nitrate between 
446 6 and 550 3 C^is given by the formula * 

/^=42 13+0 120( 450) 

A saturated solution in contact mth excess of the salt bods at 
107 2 C under 760 mm pressure 2 Its solubility m absolute alcohol 
is very slight With nitric add it yields <md n%trc&e$* of the %pe 
CsNO 3 ,HN0 3 , m p 100 C , and CsNO 3 ,2HNO 3 , m p 82 to 86 C 

Caesium phosphide, CsgPg The phosphide resembles the corre- 
sponding potassium derivative (p 181) It can be prepared by Hackspill 
and Bossuet's method (p 181, reference 8) 

Caesium phosphates In constitution and properties the phosphates 
resemble the corresponding salts of rubidium They are prepared by 
analogous methods * 

Caesium carbide, Cs 2 C 2 The carbide is prepared from caesium 
acetylide, Cs 2 C 2 ,C 2 H 2 , by a method similar to that employed for the 
corresponding rubidium compound 5 

Caesium carbonate, Cs 2 C0 3 The normal carbonate is produced by 
the interaction of the hydroxide and ammonium carbonate 6 It forms 
deliquescent, hydrated crystals, the anhydrous salt being very hygro- 
scopic, and melting at red heat When heated in vacuum it loses 
carbon dioxide It is soluble m water to a very alkaline solution, the 
heat of solution being 11 84 Cal 7 At 20 C the saturated solution 
contains 72 34 per cent of the anhydrous salt Several hydrates are 
known The heat of formation of the anhydrous salt is 274 54 Cal 8 

Caesium hydrogen carbonate, CsHCO 3 The primary carbonate is 
formed by the action of carbon dioxide on the normal carbonate, 9 and 
crystallizes m long, anhydrous prisms, stable up to 125 C , but de 
composing at 175 C with evolution of carbon dioxide and formation 
of the normal carbonate At 20 C its solubility is higher than that of 
the corresponding potassium salt, being 67 77 grams in 100 grams of 
water that of potassium hydrogen carbonate is 33 2 grams At 15 C 
the heat of solution is 4 317 Cal The heat of formation from the 
elements is 232 92 Cal The dissociation pressure has been studied 
by Caven and Sand 10 Other primary carbonates are formed by the 
action of atmospheric carbon dioxide on a solution of caesium car 
bonate 

Caesium percarbonate, Cs 2 C 2 6 A solution of the percarbonate has 
been obtained by the electrolysis of a solution of cesium cii bonate 11 

Caesium metasilicate, Cs 2 SiO 3 An investigation has been made of 
the properties of the metasilicate in dilute aqueous solution 12 

1 Jaeger and Kapma Zeitsch anorg Chem 1920 113,2? 
Jh irl of Be i k( ley and Apple bej Proc Roy Soc 1011 [A] 85 489 

3 Wells and Metzger 4wer Chem J 1901 26 271 

4 VonBcrfir, Ber 1901 34 4181 

Moissan Compt ruid 1903 136 1221 1522 

6 Bunscn and Karchhoff Fogg Annalen 1861, 113 342 1863 119 1 Annalen 
1862 122 347 186? 125 367 

7 del<orcrand Compt rend 1909 149 97 

8 de Forcrand ibid 719 

9 de Foicrand ibid 710 825 compare Bunsen and KirchhofE loc cit 

10 ( 1 aven and Sand Trans Chem Soc 1914 105 2755 

11 Piesenftld and Romhold Ber 1009 42 4377 

1 Kahlcnbtrg and Lincoln J Physical Chem 1898 2 82 

VOL II 14 



CHAPTER VIII 
AMMONIUM COMPOUNDS 

Occurrence Small quantities of ammonium salts are widely dis- 
tributed over the surface of the earth and Ihioughoul the ocean They 
are present in the Stassfurt deposits The sulphate and chloride have 
been found in the neighbourhood of active volcanoes, and the borate is 
present in the boric-acid soffiom A mineral called struvite, MgNH 4 PO 4 , 
is a product of the decomposition of animal excrement in the soil 

History The name ammonium is assigned to the radical NH 4 , 
supposed to be present in the so-called ammonium-amalgam' 1 This 
substance was first prepared by Sebeck by electrolyzing ammonium salts 
in contact with mercury, and later by Berzehus and Pontin Ampere 
regarded ammonia as the oxide of a metallic-like substance related to 
the alkalies 2 

The name ammonia is probably derived from a/x/xo?, sand 3 
The " hammomacus sal " mentioned by Pliny 4 was probably rock-salt, 
and not the modern sal ammoniac, similar terms being employed by 
Serapion and Avicenna m the eleventh centurv Geber applied the 
name sal ammomacum or sal armoniacum to ammonium chloride, and 
from the thirteenth to the seventeenth century these names were 
employed, as well as the name sal armeniacus The term sal ammonia 
cus seems to have been definitely applied to ammonium chloride from 
the eighteenth century onwards The confusion m nomenclature 
probably arose through the introduction of ammonium chloride into 
Europe from Asia about the eighth century under the name Armenian 
salt, this title being later confused with the name sal ammomacum 
applied to rock salt 

Geber's method for preparing ammonium chloride consisted m 
evaporating urine with sodium chloride, and subliming the icsidue 
The Egyptians prepared it by subliming the soot formed by the com 
bustion of camels' dung It was first produced fiom hydiogcn chloride 
and ammonia by Angelus Sala m 1620, and its qualitative composition 
was established by Glauber in 1648 

In 1595 Libavius obtained crystals of ammonium sulphate by 

1 impure sulphuric acid, and also by evaporating uunc \uth 

sulphuric acid It was investigated by Glauber, and icccivcd the name 

sal ammomacum secretum Glauben At the close of the seventeenth 

century it was much in favour as a medicine Glauber also prepaied 

1 See this series Vol III 
Compare Kopp Geschichte der Chemie Brunswick, 1845 3 250 

3 Compare Troumann Chem Zeit 1909 33 49 Schone ibid 77 von Lippmann 
tbid 117 186 Kout ibid 297 Schramm ibid 529 

4 Pliny Naturalis Historiae, Lugdim Batavorum, Rotterdam (Hackios), 1668 Vol 3 
Book 31, Chap 7, p 365 

211 



PREFACE 

thesis, which, the longer I contemplate, the mote I am 
convinced of its truth, Enough is already done to enible 
any one to form a judgment of it The facts and observa- 
tions \et in reserve, are only of the same kind as thoe al- 
ready advanced , if the latter are not sufficient to convince, 
the addition of the former will be but of little avail In 
the mean time, those who, with me, adopt the system, 
w.ll, I hive no doubt, find it a very useful guide in the 
prosecution of all chemical investigations 

In the arrangement of the articles treated of, I have en 
deavoured to preserve order, namel}, to take such bodies 
as are simple, according to our present knowledge , and 
next, those bodies that are compound* of two elements , 
but in this I have not always succeeded tor, in some in- 
stances, it has not been quite clear what was simple, and 
what compound , in other*?, the compounds of three or more 
etementb have been so intimately connected with those of 
two, that it was found impracticable to give a satisfactory 
account ot the latter, without entering moie or less into a 
description of the former. 

In regard to nomenclature, I have generally adopted 
what was most current , peihaps, in i few instances ray 
peculiar views may have led me to deviate from this rule 
I have called those salts caibonates, which ait constituted 
of one atom of carbonic acid united to one of base , ind tlit 
like for other salts But some moderns tall the neutral salts 
carbonates, and the foimtr subcarbonatcs w hertis, I should 
call the neutral carbonates of sod i and potash st/percar- 
bonatcs, consisting of two atoms of and nnd one of base I 
have, however, continued to call the common mntiUs by 
that name, though most of them must be considued on my 
system as supernitrates J am not very an\iuus upon tins 
head, is it is evident that if the system I proceed upon \ i 
adopted, a general reformation of nomenclaiuit uill be the 
consequence, ha\ ing a reference to the nnmler of clouts, rt s 
well as to the kind qfeLtuints, constituting the different 



AMMONIUM COMPOUNDS. ^ 213 



of bromine on ammonium salts ftirnist&s & n$a&s of comparing the 
extent of their hydrolytic dissociation Under certain conditions the 
action on free ammonia is represented by the equation 



and for the ammonium safe its vekxaty increases TOfch t&e by<Jrotytie 
dissociation x Other methods of determining tibe degree of &yefeolysis 
have also been devised 2 

Ammonium ion and Valency Although no direct measurement of 
the electroaffinity of the ammonium ion has been possible, tiie s%fet 
tendency to hydration of its sate indicates that it is strongs tbaa tfce 
potassium ion It is colourless, and the m^afoonrioeloc&y at 18 C s is 
given as 64 2, and at 25 Q C 4 as 78 Like the alkali-metals, the radical 
ammonium is umvalent, and forms salts with one equivalent of an acid 

AMMONIUM SALTS 

Ammonium fluoride, NH 4 F The fluoride is foraged by the 
action of gaseous hydrogen fluoride and anhydrous ammonia It 
be prepared by sublimation from a mixture of amnaoniom chloride 
sodium fluoride 5 It forms very brittle, colourless, hexagonal lamiaae * 
of strongly saline taste In dry air it is stable at ordinary temp&ature 
When heated, it fuses, and then sublimes The dry salt can absorb 
ammonia at ordinary temperature, the gas being expelled by heat It 
is deliquescent, and dissolves in its ovra. weight of water at C 7 In 
aqueous solution it undergoes extensive hydrolytic dissociation In 
consequence of the presence of free hydrogen fluoride, the solution 
attacks glass, and should be stored in vessels made of platinum, silver, 
or gutta-percha 8 Explosive, oily drops of nitrogen fluoride are said to 
be formed by its electrolysis, 9 but the statement lacks confirmation 7 
It is employed as a disinfectant in the brewing industry, 10 and is a power- 
ful preservative, almost inhibiting the fermentation of invert-sugar n 

The heat of formation of the solid from gaseous ammonia and 
hydiogen fluoride is 37 3 Cal , and the heat of neutralization of the acid 
by ammonia in aqueous solution is 15 2 Cal 12 

Ammonium hydrogen fluoride, NH 4 F,HF Evaporation of a solu 
tion of the normal salt at a temperature between 36 and 40 C expels 
ammonia, the primary salt crystallizing out It can also be prepared 
by the action of ammonia on a solution of hydrogen fluoride, a small 
proportion of ammomum sulphide or carbonate being added 13 It 
forms colouiless rhombic prisms, readily soluble in water, 6 with a 
density of 1211 14 at 12 C 

I Ostwald and Kaich Ztit^h phytilal Chem 1888 2, 12o 

Compile Veley Tran* Chem boc 1905 87 2b Hill ibid 1900 89 1273 
Naununii and Ruckci J piaU Chem , 1905, [2] 74 249 Nauinami md Muller ibid 
215 Oo&binann Zeittch anory Chem 19U2 33 149 

* Kohhausch ind Holborn Leihermogtn dei EleLtiolyU Leip&ic lb9S 
4 Brcdig Zeit&ch physilal Chem 1894 13 22b 

Berzeliiib Lehrbuch der Chemie 6th ed Leipsic Ibob 3 2b2 

b Marignac Ann Mines 1859 [o] 15 221 Ruff and Gu^tl Btr 1903 36 2b 7 

8 Ko^e Poyq Annahn 1859 1 08 19 9 Warren Chan A two Ibh7 55 289 

10 Will and Biaun Zukch get> BiauiL 1904 27 521 o37 5o3 

II Luhug and Saiton Pharm ZentrdLhalle 190b 49 934 

1 Guntz Compt rend , 1883 97 1483 Ann Chun Phy* Ibb4 [b] 3517 

13 Kose loc cit 

14 Bodeker, Beziehungen zvnschen Dichte und Zusammensetzuny Leipbic, 1860 



CONTENTS 

PAflfi- 

SECTION 6* Hydrogen with Azote * - - - - -415 
Ammonia -----* 41(5 

SECTION 7 Hydrogen &ith Cm bone 

Olejiant gas *..-- 437 
Cfirburettcd hydrogen ----- 444, 

SECTION 8 Hydrogen uith Sulphur 

Sulphwettedhydjogen ..... 450 
Supersutphurettcd hyd) ogen - - -453 

SECTION 9 Hydrogen with Phosphorus 

Phosphuretted hydiogcn - - - -456 

SECTION 10 Cm bone uith Sulphur, utth Phosphorus, 

andSulpkw nth Phosphorus - - -462 

SECTION 11 Fixed Alkalies 

Potash ......... 463 

Hydrate of potash ------ 47 5 

Carbonate of potash - - - - - 479 

Potasium or hydrw ct of potash - -484* 
Soda ......... 492 

Hydrate of soda - - - - - 495 

Carbonate of soda - - - - - 497 

Sodium or hydi itrct of soda - - - 502 

SICTIO*. 12 Earths .......... 50 1 

Lime ......... - 505 

Magnesia ------ --512 

Buri/tes ---..-. - 518 
Stwntites -----_,^ r )j4 

dlumme ot aigil ------ 5*27 

Silex ......... 5J6 



Glucine 



Explanation nf Pla Us 
rfppcndiv 



AMMOHIUM COMPOUNDS. gi3 

/"-tV ftiJV 

of bromine on ammonium salts furnishes a Bleaks of eompanng the 
extant of their hydrolytac dissocaa&on* Under certain condStaoas the 
action o$ free ammonia is represented by the equation 



and for the ammonium salts its velocity increases with the hycfaolyfee 
Association x Other methods of determining the degree of hydrolysis 
have also been devised 2 

Ammonium ion and Valencj Mlhougli no ctawfe m^asurema&t of 
the electroaffimty of the ammonium ion Thas been possible, the slight 
tendency to hydration of its salts indicates that it Is stranger than the 
potassium ion It is colourless, and the mvgra&onwdoetiy at 18 C * i$ 
given as 64 2, and at 25 C 4 as 7S Like the alkak-metate, the radical 
ammonium is umvalent, and forms safe with one equivalent of an 

AMMONIUM SALTS 

Ammonium fluoride, NH 4 F The fluoride is formed by t&e m 
action of gaseous hydrogen fluoride and anhydrous ammonia It can 
be prepared by sublimation from a mixture of ammonium chloride and 
sodium fluoride 5 It forms very brittle, colourless, hexagonal laminae 6 
of strongly saline taste In dry air it is stable at ordinary temperature 
When heated, it fuses, and then sublimes The dry salt can absorb 
ammonia at ordinary temperature, the gas being expelled by heat It 
is deliquescent, and dissolves in its own weight of water at C 7 In 
aqueous solution it undergoes extensive hydrolytic dissociation In 
consequence of the presence of free hydrogen fluoride, the solution 
attacks glass, and should be stored in vessels made of platinum, silver, 
or gutta-percha 8 Explosive, oily drops of nitrogen fluoride are said to 
be formed by its electrolysis, 9 but the statement lacks confirmation 7 
It is employed as a disinfectant in the brewing industry, 10 and is a power- 
ful preservative, almost inhibiting the fermentation of invert-sugar n 

The heat of formation of the solid from gaseous ammonia and 
hydrogen fluoride is 37 3 Cal , and the heat of neutralization of the acid 
by ammonia in aqueous solution is 15 2 Cal 12 

Ammonium hydrogen fluoride, NH 4 F,HF Evaporation ol a solu- 
tion of the normal salt at a temperature between 36 and 40 C expels 
ammonia, the primary salt crystallizing out It can also be picpared 
by the action of ammonia on a solution of 1 \u jr fluoride, a snull 
propoition of ammonium sulphide or carbonate being added 13 It 
forms colouiless ihombic prisms, leadily soluble in water, 6 \\ith a 
density of 121 1 14 at 12 C 

I Ofatwald and Raich Zeittch phytikal Chem ISbb 2 12o 

Compile Veley Ttati* Chem Soc 190o, 87 2b Hill ibid 190b 89 1273 
Naumann ind Ruckci J piaU Chem , 190o [2] 74 249, Nauuiami and Alulki ibid 
215 Orossmann Zeitsch anory Chem 1902 33 149 

3 Kohhausch and Hoi born Leitiermogtn dei Eld tro1yt<. t Lcip&ic 1S98 

4 Bredig Zeittch phy&iLal Chem 1894 13 228 

Berzehus LchrbucH der Chemie 6th ed Leipsic, Ib5b 3 2b2 

1 Maugnac Ann Mines 1859 [o] 15 221 Ruff ami Gei&el Btr 1903 36 2b 7 

8 Rose Poyq Annalen 1859 108, 19 9 Warren Chem Veii* Ibb7 55 289 

10 Will and Biaun ZeiUch get, Btauw 1904 27 521 o37 5o3 

II Luhng and Saitori Phann Zentralhalle 1908 49 934 

x - Guntz Compt rend 1883, 97 1483 Ann Chim Phyt> 1884 [b] 3 5 17 

13 Rose loc cit 

14 Bodeker, Beziehungen zvnschen Dichte und Zusammensetzung Leip&ic 1860 



222 ON ELEMENTARY PRINCIPLES 

that any one of the bodies denominated ele- 
mentary, is absolutely indecomposable , but 
it ought to be called simple, till it can be 
analyzed The principal simple bodies are 
distinguished bv the names oxygen, hydrogen, 
azote or nwogm, carbone or charcoal, sulpkw , 
phosphorus, and the metah The fixed alkalis 
and the earths were lately undecomposed , 
but it has long been suspected that they were 
compounds , and Mr Davy has recently 
shewn, by means of galvanic agency, that 
some of them contain metals, and have all the 
characters of metallic oxides , no harm can 
arise, it is conceived, therefore, from placing 
all the earths in the same class as fhe metallic 
oxides 

After the elementary or simple bodies, those 
compounded of two elements inquire next to 
be considered These compounds form a 
highly interesting class, in which the new 
principles adopted are capable of being exhi- 
bited, and their accuracy investigated by d- 
rect e^penment In this class we find several 
of the most important agents in chemistry , 
namely, water, the sulphuric, nitric, muri- 
atic, carbonic and phosphoric acids, most of 
the compound gases, the alkalis, earths, and 
metallic oxides 

In the succeeding classes we shall find the 



AMMONIUM COMPOUNDS. 

A solution in contact tnth excess of the safe boaJs at 115*6 C , 
at that temperature contains 87 3 grams per 100 grains of water At 
75 C a similar solution < onUms 38 23 grains of the sate pear 100 gratis 
of the solution * In dilute aqueous solution its degcee of K>mzafeos* is of 
the same order as that of potassium c& sodium chkaade, 2 

The volatilization of ammonium chloride by heat is attended by 
much dissociation 3 in presence of moisture, corresponding with 67 to OS 
per cent , and a slight decrease in the extent of the fesocaataoa b$$wee& 
280 and 330 C 4 Absence of water-vapour almost entirely pseyeats 
the dissociation of ammonium chlonde > and the combination of hydjogieagt 
chloride and ammonia 5 

The heat of neutralization of ammonia and hydrogen chloride m 
aqueous solution is given as 12 27 Cat 6 and 12 45 Cal 7 At orcteaiy 
temperature this solution is not afosokrtdy stable 8 Whaa heated, it 
evolves ammonia, aad develops an acidtc reaefeon 9 

When ammonium chloride is heated in contact with air actd platanum, 
there is partial oxidation with formation of mtoc acid &, Wbearafe^pt of 
chlonne Heating the salt with gaseous hydrogen iodide &iso causes 
decomposition 10 , and heating with potassium forms potassium 
chloride, with evolution of ammonia and hydrogen It is also decom- 
posed by other metals At a red heat it converts many salts and 
oxides into chlorides, 11 but the oxides of cobalt and nickel are reduced 
to the corresponding metal ^ At 400 C it reacts with carbonyl 
chloride, COC1 2 , to form carbamyl chloride, Cl CO NH 2 13 When heated 
with potassium dichromate, it is decomposed with evolution of nitrogen, 
nitric oxide, nitrogen peroxide, and chlonne 14 It combines with 
ammonia to form complex derivatives, 15 an additive compound pre- 
pared by Kendall and Davidson 16 having the formula NH 4 C1,3NH 3 , 
and the melting-point 10 7 C 

Ammonium chloride exerts a catalytic, accelerating effect on certain 
reactions, examples being the interaction of lodic acid and sulphurous 
acid, 17 and the inversion of sucrose by hydrochloric acid 18 It is em- 
ployed m the manufacture of ammonia and ammonium compounds, in 
pharmacy and the dye industry, and m soldenng 

1 Tschugaev and Chlopin Zeitsch anorg Chem ,1914 86, 154 
Noyes, Zeitsch physilal Chem 1882 9 608 

3 Than Annalen 1861 131 131 Bmeau Ann Chim Phys , 1863 [3] 68 416 
Ramsay and Young, Zeitsch physilal Chem 1887 I 244 

4 Smith and Lombaid J Amer Chem Soc 1915 37 38 

5 Baker Trans Chem Soc , 1894 65 611 1898 73,422, compare Gut maim Annalen 
1897 299 267 

6 Thomsen Thermochemistry (Longmans, 1906), 115 

7 Berthelot Compt )end 1873 76, 1041 llOb 

8 Leeds, Chem Jhews, 1879 39 17 Amer Chem J IbSO 2,246 compare Conm all 
ibid 45 

8 Watson Smith J Soc Chem Ind 1911 30 2o3 Leeds -imcr J bci 1874 [3] 
7,197 Chem Aews 1874 29, 25b Arch Sci phyt> nut , 1874 50 214 

10 Hautefeuille Bull &oc chim 1867 [2] 7 19b 

11 Compare Gmelm Kraut Handbuch der anorg Chem , Heidclbei^, 1672-1697 2 i 422 
1 Santi Boll chim farm 1904 43 b73 

13 Gattermann and bchmidt Ber 1887 20 808 

14 Irankforter Roehrich and Manuel J Amer Chun hoc 1910 32 17b compare 
de Luna Ann Chim Phys 1863 [3] 68 183 

15 Troost Compt rend 1879 88 578 

18 Kendall and Davidson J Ame> Chem boc 1920 42 1141 

17 Landolt Sitzungsbe) K Alad Wiss Bulin 1887 21 745 

18 Arrhemus, Zeitsch physikal Chem 1889 4 240 



224 ON OXYGEN 

be received in phials over water, in the usual 
way About SO cubic inches of gas may be 
expected This gss should be exposed to a 
mixture of lime and water, which absorbs 
about | of it (carbonic acid), and leaves the 
rest nearly pure 

2 With the application of heat Put 2 
ounces of manganese (the common black oxide) 
into an iron bottle, or gun barrel properly pre- 
pared, to which a recurved tube is adapted 
This is then to be put into a fire, and heated 
red , oxygenous gas will come over, and may 
be received as before , it usually contains a 
small portion of carbonic acid, which mav be 
extracted by lime water Three or four pints 
of air may thus be obtained 

3 Two ounces of manganese may be put 
into a phial, with the same weight of sulphuric 
acid , the mixture being made into a paste, 
apply the heat of a candle or lamp, and the 
gas comes over as before, nearly pure, if taken 
over water 

4 If an ounce of nitre be put into an iron 
bottle, and exposed to a strong red heat, a 
large quantit) of gas (2 or 3 gallons) may be 
obtained It consists of about 3 parts oxygen 
and 1 azote, mixed together 

5 Put 100 grams of the salt called oxy- 
munate of potash into a glass or earthenware 






AMMONIUM COMPOUNDS 217 

nvatwes, 1 an example being the substance 2 me&mg at 13 7 C > and 
havmg the formula NH 4 Br,8NH 3 

Ammonium iodide, KEJ 4 L The iodide is formed by methods 
analogous to those apphcable to the bromide 8 It is also a prodoefe of 
the decomposition of nitrogen iodide in presence of water or ammonium 
hydroxide 4 It is best prepared by addition of alcohol to an aqueous 
solution of potassium iodide aad ammonium sulphate m eqmBK)!eeolar 
proportions, potassium sulphate crystallizing and ammonium iodJe 
remaining dissolved 5 It can also be prepared by the 
of ferrous iodide and ammonium carbonate, and by that of < 
hydroxide and iodine in presence of hydrogen peroxide s 

2NH S +2I+H 2 2 =2NH 4 I+0 2 

Ammonium iodide crystallizes in colourless dehquesoe&t cubes, 
of density 2515 7 at 20 C For the meltang-point Rassow* 
551 3 C , an accurate determination bemg prevented by 
sociation Heatnig causes sublimation, acoompamed by ateosfc com- 
plete dissociation, 9 and in presence of air a certain cfeg^e& *ty 
decomposition The initial effect of heat is to cause the vajpo&t t^ 
associate, the degree of association diminishing with rise of temperatiU^ 3 ^ 
The heat of formation from the elements is 49 31 Cal , and from gaseous 
ammonia and hydrogen iodide 43 46 Cal u At 15 C its solubility is 
167 grams in 100 grams of water 12 In concentrated aqueous solution it 
is converted by iodine into the tn-iodide, 13 NH 4 I,I 2 , tabular, rhombic 
crystals, isomorphous with the tn-iodides of the alkali-metals u With 
ammonia, ammonium iodide yields additive compounds 15 One example 
is the substance melting at 8 C , with the formula NH 4 I,3NH 3 , and 
another that melting at 5 1 C , with the formula NH 4 I 5 4NH 3 

In aqueous solution ammonium iodide is gradually oxidized, the 
reaction being accelerated by light 16 The salt finds application in the 
photographic industry 

Ammonium dicnloroiodide, NH 4 C1 2 I The liquid obtained by the 
action of chlorine on an aqueous solution of ammonium chloride con- 
taining iodine in suspension, until the free iodine has just disappeared, 
deposits scarlet pi isms of ammonium dichloioiodide This peihalide 
is also formed by the interaction of an aqueous solution of ammonium 
iodide and chlorine It is the most stable of the trihahdcs, and can be 

1 iiuobt Co nipt lend 1881 92 715 Roozeboom Zeihch phy&iLal Chem 1888 
2 4bO Re(; t)av chun , 1885 4 301 

Kendall and Davidson J Amer Chem Soc 9 lQ20 42 1141 

3 Compaie Schonbem J prakt Chem ISbl 84 385 

4 Guyaid Compt rend 1883 97 52b I/on Scient 1883 [3] 13 1011 

5 Jacobscn Neues Jahrb Pharm 1864 20 91 

6 Broeksmit, Pharm Weckblad, 1917 54 1373 cornpaie Rupp Ipoth Zeit , 1918, 
33 40b, 473 

7 Le Blanc and Rohland Zeitsch physikal Chem I89b 19 2bl 

8 lla&sow Zteitsch anotg Chem 1920 114 117 

9 Dcvillc and Iroost, Cotnpt lend 18o9 49 239 I8b3 56 891 Innahn 1860 
113 42 1863 127 274 

10 Smith and Lombard J Amer Chem Soc 1915 37 38 
1 Thomson, Thermochemistry (Longmans, 1908) 2ol 
Ldu- Dingier s Polyteeh J 1870 221 189 

3 Johnson Chun \ews 1878 37 270 Tian* Chem hoc 1878 33 397 

4 Wheeler Barnes and Pratt 4.mer Chem J 1897 19 b72 

5 Kendall and Davidson J Amer Chem Soc, 1920 42 1141 
45 Leeds, Pharm J , 1879, [3], 9, 1017 



226 PROPERTIES OF OXYGEN 

by 7, that of an atom of hydrogen being 1 ; 
this is inferred from the relative weights of those 
elements entering into combination to form 
water The diameter of a particle of oxygen, 
in its elastic state, is to that of one of hydrogen, 
as 794 to 1 * 

2 Oxygen unites with hydrogen, charcoal, 
azote, phosphorus, and other bodies denomi- 
nated combustible, and that m various man- 
ners and proportions , when mixed with hy- 
drogen and some other elastic fluids, it ex- 
plodes by an electric spark, with noise, and a 
violent concussion of the vessel, together with 
the extrication of much heat This is called 
detonation In other cases, the union of oxy- 
gen with bodies is more slow, but accom- 
panied by heat This is usually called com- 
bustion, as m the burning of charcoal , and 
inflammation, when accompanied with flame, 
as m the burning of oil In other cases, the 
union is still more slow, and consequently with 

*For, the diameter of an elastic paiticle is a^ 3 V (weight 
of one atom specific gravity of the fluid) \\ huicx, de- 
noting the weight of an atom oi hydrogen bv 1, nnd the 
specific gravity of hydrogenous gas also by 1, the weight 
of an atom of oxygen will be 7, and the specific giotviiy of 
ox>genousgas, 14, we have then VY* ' or V* 1 * 
or 794 1 diarnetei of an atom oi o\) gen the diameter 
of one of hydrogen 



AMMOHEUM COMPOTmDS. 



composed by heat, slowly between 145 ainl 15? C , iapKlj at 180 C ,* 
and is employed in the manufacture of explosives** 

Ammonium hypobixmMte*--Broi3aine is md to i^a^ wilfe weft- 
cooled ammonium-hydroxide solution, with formation of an unstable 
solution of the hypobromite * 

Ammonium bromate, NHjBrO,. Evaporation <rf aa asqdeoos 
solution of ammonia and bromic acid* or of bajiura bsomafee $ad 
ajnmonmm carbonate, yields the bromate m db^nri^ss needles, Tbey 
are very unstable, and decompose with some energy at ordinary tesaa- 
peratures 4 

Ammonium hypoiodrte A very unstable solution of the tcypotoJUe 
is probably formed by addition of excess of ammonium hydroxide to aa 
aqueous solution of iodine The solution exerts a powerful bleadbmg 
action, but rapidly decomposes mto iodine and lodate 

Ammonium lodate, NH 4 IO S The lodate is produced by the a$a 
of ammonia or ammonium carbonate on lochc acid or iodine traeblondtav 
and is also one of the products of the interaction of loetee ad 3mmw&.* 
It forms colourless rhombic 7 crystals, of density a B085 8 at 21 Q C , its 
solubihty at 30 C being 4 2 grams in 100 grams of water * At 150 C, 
it decomposes energetically mto oxygen, nitrogen, iodine, and water w 
Acid salts derived from one molecule of the lodate and one molecule u 
or two molecules ** of lodic acid have been described 

Ammonium penodate, NH 4 I0 4 Neutralization of periodic acid 
with ammonia yields the penodate in tetragonal crystals isomorphous 
with the corresponding potassium, sodium, and rubidium salts, 13 and also 
with the penodates of silver and lithium 14 Its density at 18 C is 
3 056 , and its solubility at 16 C is 2 7 grams in 100 grams of water 15 
Several hydrates 16 and complex penodates 17 have been described, 
examples being (NH 4 ) 2 H 3 IO 6 , prepared by Rammelsberg and Groth, 18 
and (NH 4 ) 3 H 7 (I0 6 ) 2 ,2H 2 O 19 The hydrated salt with the second formula 
is obtained in the form of rectangular crystals by agitating periodic 
acid with excess of 25 per cent ammonia at 140 C for several hours 

1 Giraid and Laroche Mon Scient 1909, [4], 23 i , 217 

2 Alvisi, Gazzetta 1899, 29, i 121 

3 Maumen6 Oompt rend 1870 70 147 Kraut Gmelin Kraut $ Handbuch der anorg 
Chem , Heidelberg, 1872-1897 2 i , 560 Foster, Trans CUem Soc 188b 33 470 
Bosetti Atch Pharm 1889 [3] 27 120 

4 Kammelsberg Pogg Annalen 1833 52 85 compare Rctgers ZeiUck physilal 
Chem 1890 5 436 

5 Compait, Gmelin Kiaut Handbuch der anorg Chem , Heidelberg IbT 2-1897 2 i 
2b9 495 

6 Gmelin Kiaut ibid Guyard, Compt rend 1683 97 j2b Mon Scient 1883 
[3], 13 1011 

7 kakle Zeitsch Ktyst Mm , 1896 26 5o8 , Ries ibid 1905 41 243 

8 Clarke A met J Sci 1877 [3], 14 281 

9 Meerburg Zeitsch anoig Chem 1905 45 324 

10 P t _ P ig Annahn, 1838, 44 555 

11 \> ' / ( Phys 1890, [6] 21 146 

12 Meerburg loc cit Blomstrand / pralt Chem 1889 40 33b 

13 Barkci Tran* Chem hoc , 1908 93 lo 

14 Rammelsberg Pogg Annalen 1868 134 368 15 liaikti loc cit 

16 Eakle Zeitsch Ktyst Mm 1896 26 558 Hire Ber 1876 9 316 Lan^lois 4 
Chim Phys 1852 [3] 34 257 Annalen 1852 83 Io3 

17 Hue loc cit Rammtlbberg and Groth Pogg Annahn 1868 134 379 

18 Rammelsberg and Groth, loc cit compare Rosenheini and Loeutnthal Kolluid 
Zeitsch , 1919 25 53 

19 Rosenheim and Loewenthal loc cit 



228 ON HYDROGEN* 

per cent oxygenous gas , the air expired, usu- 
ally contains about 17 percent oxygen, and 4 
carbonic acid But if a full expiration of air 
be made, and the last portion of the expired 
air be examined, it will be found to have 8 or 
9 per cent carbonic acid, and to have lost the 
same quantity of oxygenous gas 

4 Oxygenous gas is not sensibly affected by 
continually passing electric sparks or shocks 
through it , nor has any other operation been 
found to decompose it 



SECTION 2 

HYDROGEN 

Hydrogenous gas may be procured by tak- 
ing half an ounce of iron or zinc filings, turn- 
ings, or other small pieces of these metals, 
putting them into a phial, wirh two or three 
ounces of water, to which pour one quarter as 
much sulphuric acid, and an effervescence 
will be produced, with abundance of the gas, 
which may be received over water in the 
usual way 

Some of its distinguishing properties are 
1 It is the lightest gas \uth which we 
are acquainted Its specific gravity is nearly 
0805, that of atmospheric air being 1 This 



AMMONIUM COMPCOTSIDa 

and readily decomposed into ammonia and ammonium hydrogen sul- 
phide Bloxam 1 regards the ordinary solution of ammonium sulphide 
as (NH 4 )^S,2NH 4 SH+2NH 4 OH Several complex denrafaves mth 
ammonia have been described* 2 The heat of formation of the s&lpiodb 
from ammonia and hydrogen sulphide in aqueous solution ts grm* as 
6 2 Cal 3 and 6 3 Cal * 

Ammonium hydrogen sulphide, NH 4 SH The primary salpMe s 
formed m white crystals by tie interaction of ammonia and hyclrogea 
sulphide in ethyl-acetate solution 5 At or below C it undergoes cSly 
a slow decomposition into hydrogen sulphide and aznmosxa. Its 
melting-point m a closed vessel is 120 C 6 Its heat of formation foom 
sulphur-vapour, hydrogen, and nitrogen has been calculated 7 to be 
42 4 Cal In aqueous solution it undergoes extensive hydrolytie dis- 
sociation, and the strongly alkaline solution is oxidised by exposure to 
air, yielding a yellow solution ( on! <n rung jx>l\ sulphides and also sulphite 
and thiosulphate 8 This liquid constitutes the ordinary solution of 
ammonium sulphide employed in analysis , it can also be prepared by 
dissolving sulphur in a solution of ammonium hydrogen sulphide, or 
by distilling a hot solution of sodium sulphide and ammonium cHoi&le.^ 

The so called " volatile liver of sulphur " is a mixture of aminoraam 
hydrogen sulphide and polysulphides, and is obtained as a dark-red, 
fuming liquid by distilling ammonium chloride, sulphur, and hme ie 

Ammonium polysulphides Various solid polysulphides have been 
described, 11 but there is no certainty that they are true compounds 
Examples are the tetrasulphide, (NH 4 ) 2 S 4 , unstable yellow crystals 
prepared by cooling the mother-liquor of the pentasulphide after 
treatment with hydrogen sulphide and ammonia, and along witl 
pentasulphide by the action of these reagents on a solution ol LUC 
enneasulphide , the pentasulphide, (NH 4 ) 2 S S , rhombic orange crystals 
obtained by dissolving sulphur in a warm solution containing hydrogen 
sulphide and ammonia in the ratio 1 2, or by addition of alcohol to 
a cold concentrated solution of ammonium sulphide saturated with 
sulphur 12 , the heptasulphide, (NH 4 ) 2 S 7 , 13 ruby-red crystals produced by 
dissolving the pentasulphide in its own mother-liquor and allowing 
the solution to crystallize, or as crystals of violet lustre and the 
formula 3(NH 4 ) 2 S 7 ,4H 2 O by saturating a concentrated solution of 
ammonia with hydrogen sulphide and sulphur, and the enneasulphide, 
(NH 4 ) 2 S 9 ,JH 2 O, deep red crystals deposited from the mothei -liquor of 
the pentasulphide after prolonged exposure to air 

1 Bloxam Zeitsch anorg Chem 1908 60 113 
Bloxam, Chem News 1893 68 97 Maumene Compt tend 1870 89 506 

3 Berthelot Ann Chim Phys 1875 [5] 4 187 

4 Thomson Thermochemische Unteisuchungen Leipsic 1882-1883, I 2G4 

5 Naumann Bet 1910 43 U3 compare Tioovt Cornet icml ls7 ( > 88 1207 

6 Brmer Compt tend 1906 142 1416 

7 Berthelot ibid , 1880 90 779 Ann Chun Phy* lst>o fo] 20 Jlj 
s Bloxam Chem \ews 1893 68 97 Trans Chem Sof 1893 67 277 
9 Donath Chem Zeit 1891 15, 1021 

10 GayLussac Pogg Annalen 1829 15 538 Ann Chun Phy 1S20 4 302 
Vauquelin ibid 1817 6 42 

11 Fntzsche J pralt Chem, 1841 24 460 1844 32 313 Bloxam Tian* Chem 
Soc 1895 67 277 

12 Byers Amer Chem J 1902 28 490 

13 Fritzsches heptasulphide is regarded by Sabatier (-4wn CJnm Pity* 1881 [o] 22 
73) as an octasulphide, (NH 4 ) 3 S 8 



230 PROPERTIES OF HYDROGEN 

stantly condensed into water When 2 mea- 
sures of hydrogen are mixed with 1 of oxygen, 
and exploded over water, the whole gas dis- 
appears, and the vessel becomes filled with 
water, 10 consequence of the formation and 
subsequent condensation of the steam 

If 2 measures of atmospheric air be mixed 
with 1 of hydrogen, and the electric spark 
made to pass through the mixture, an explo- 
sion ensues, and the residuary gas is found to 
be 1| measures, consisting of azote and a small 
portion of hydrogen The portion of the mix- 
ture which disappears, 1 T , being divided by 
3, gives 42 nearly, denoting the oxygen in 
two measures of atmospheric air, or 21 per 
cent The instrument for exploding such mix- 
tures in is called Voltcts eudiometer 

5 Another remarkable property of hydrogen 
deserves notice, though it is not peculiar to it, 
but belongs in degree to all other gases that 
differ materially from atmospheric air in spe 
cific gravity , if a cylindrical jar of 2 or more 
inches in diameter, be filled with h)drogen, 
placed upright and uncovered for a moment or 
two, nearly the whole will \anish, and its 
place be supplied by atmospheric air In this 
case it must evidently leave the vessel in a 
body, and the other enter in the same manner 
But if the jar of hydrogen be held with Us 




AMMONIUM COMPOUNBS. 

and of coke in coke-ovens, furnishes the mam balk of the world's supply 
of ammoniiftn sulphate Most of the ammonia is dissolved m the con- 
densed aqueous vapour obtained by ooolmg the gas, asad tbe residual 
portion is extracted by washing with water In coke-works the 
ammonia is sometimes absorbed from the hot gas by means 
acid, after the removal of the tar 

The free ammonia in the aqueous solution is expelled by heat, 
absorbed by sulphuric acid in a lead saturator , aad the fixed ammoma, 
is then liberated by lime, and similarly absorbed 

In Woltereck's process for the manufacture of ammonia from peat, 1 
earned on at Carnlough in the north of Ireland, the wet peat is faroat $& 
air and steam at a low temperature After the tar produced has b* 
washed out by oils of high boiling point, and the acetic aeid removed by 
hot milk of lime, the ammonia is absorbed by sidphunc acid 

The sulphate crystallizes in transparent rhombic crystals, 2 
morphous with those of potassium sulphate lie effect of v 
impurities on the colour of the salt has been investigated Jby 
The literature contains many contradictory statements respecting the 
melting-point of ammonium sulphate and the behaviour of the subs-tanoe 
under the influence of heat According to Marchand, 4 the melting-point 
is 140 C , but Watson Smith 5 and Caspar 6 regard this temperature as 
the melting-point of the primary sulphate Watson Smith 7 states that 
ammonium sulphate begins to evolve ammonia at 100 C , and at 
800 C is completely converted into the primary sulphate According 
to Caspar, 6 in an open tube the normal sulphate softens at 310 C , 
melts at a temperature between 336 and oon r - 
with evolution of gas at 355 C , in a clos 
about 360 C, and melts between 417 ana <*AO ^ jdiiecK.e~ 
that both the normal sulphate and the primary sulphate melt at 
251 C , but m a later paper 9 gives 147 C as the melting-point of the 
primary sulphate The explanation of these very divergent values is to 
be found in the observation by Kendall and Davidson 10 of the im- 
possibility of determining in an open tube the true melting-point of 
the normal sulphate, owing to loss of ammonia even at 200 C When 
the salt is heated in a sealed tube almost filled, it softens at 490 C and 
melts at 513 + 2 C , the value given representing the melting point of 
the substance at an ammonia pressure of considerably more than one 
atmosphere When the salt is heated m an open tube, decomposition 
is complete at 365 C n 

Janecke's 8 value for the boiling point of the normal sulphate, 
357 C , does not accord with the work of Kendall and Davidson 12 The 

1 Woltereck British Patents, 1904 No 16504 1906 Nos 28963 and 28964 

2 Mitscherhch Pogg Annalen 1830 18, 168 Tutton, Trans Chem &oc 1903 83 
1049 Zeitsch Kryst Mm 1905 41 525 

3 Leo Stahl und Eisen 1914 34 439 

4 Marchand Pogg Annalen 1837 42 556 

5 Watson Smith J Soc Chem 2nd, 1911 30 253 compare Reik Moyiatsh 1902 
23 1033 

6 Caspar Ber 1920 53 [B], 821 

7 Watson Smith loc cit 

8 Janecke Zeitsch angew Chem 1920 33 278 

9 Janecke, ibid 1921 34 542 

10 Kendall and Davidson, J Ind Eng Chem 1921 13 303 compare Kendall and 
Landon, J Amer Chem Soc , 1920 42 2131 Kattamkel Ber 1922 55 [B] 874 

11 Kattwinkel, loc cit 1 Kendall and Da\idson loc cit 



232 PROPERTIES OF AZOTE 

100 measures of atmospheric air put 30 of 
nitrous gas > the mixture having stood some 
time, must be passed two or three times 
through water , it will still contain a small 
portion of oxygen , to the residuum put 5 more 
measures of nitrous gas, and proceed as before , 
small portions of the residuum must then be 
tried separately, by nitrous gas and by atmo- 
spheric air, to see whether any diminution 
takes place , whichever produces a diminution 
after the mixture, shews that it is wanting, 
and the other redundant , consequently a small 
addition to the stock must be made accord- 
ingly By a few trials the due proportion may 
be found, and the gas being then well washed* 
may be considered as pure azotic 2 If a 
quantity of liquid sulphuret of lime (a yellow 
liquid procured by boiling one ounce of a mix- 
ture of equal parts sulphur and lime in a quart 
of water, till it becomes a pint) be agitated in 
2 or 3 times its bulk of atmospheric air for some 
time, it will take out all the oxvgen, and leave 
the azotic gas pure 3 If to 100 measures of 
atmospheric air 42 of hydrogen be put and 
an electric spark passed through the mixture, 
an explosion will take place, and there will be 
left 80 measures of azotic gas, &c 
The properties of this gas are , 
1 The specific gravity of azotic gas at the 



AMMONIUM 

Ammonium hydrogen solpiiate, NH 4 fiSO 4 On cooling a saturated 
solution of the normal sulphate in <xmcentarated sulphuric add* the 
primary sulphate is deposited m deliquescent* rhombic pnsEos. 1 It is 
also produced by heating the normal salt, 2 For the metaog^poiiitof the 
primary sulphate, 3 Watson Smith 4 gives 140 C , but xaore 
can be placed on the value 140 9^ 5 C of Kendall aad 
and on that (147 C ) of Janeeke s For the bodmg-pooat Jaaaeefee 7 
gives 490 C The density of the primary sulphate is given as 1 787 
and 1 815 9 It is soluble m an equal weight of water, 16 Several other 
acid sulphates have been described, 11 such as (NH^^SO^BH^O^ 
melting at 48 C 12 An ammonia compound, (NH^aSO^NH^ has also 
been prepared ** 

Ammonium pyrosulphate, (NH^gSgO Sulphur tnoxide combines 
with ammonium sulphate with evolution of heat, yielding tlie 
sulphate as an amorphous, translucent, deliquescent substa&ee, : 
crystalline by fusing and allowing to solidify Its melting-point is 
given as 138 C 13 The primary sulphate crystallizes from its solution ** 

An octasulphate, (NH 4 ) 2 O,8S03, has also been described B 

Ammonium persulphate, (NH 4 )2S 2 O 8 The persulphate is produced 
at the anode m the electrolysis of a cooled saturated solution of am- 
monium sulphate in dilute sulphuric acid, a high anodic current-density 
and a diaphragm being employed 16 It can also be prepared technically 
without a diaphragm 17 It forms monochmc crystals, 18 its solubility at 
C being 58 grams m 100 grams of water, 19 and greater than that of any- 
other persulphate 20 If free from moisture ftT ^ 
the dry salt scarcely undergoes any chang~ 
When warmed with mtnc acid it evolves oz^xx. 
than the corresponding salts of sodium and 
affording a method of preparing this gas 22 It converts metallic oxides 
into persulphates, peroxides, or sesquioxides, with evolution of ammonia ^ 

1 Mangnao Ann Mines, 1857 [5], 12 38 

2 Watson Smith J Soc Chem Ind 1911,30,253, compare Reik Monatsh 1902 
23, 1033 

3 Compare the section on normal ammonium sulphate 

4 Watson Smith loc cit 

5 Kendall and Landon J Amer Chem Soc , 1920 42 2131 compare Kendall and 
Davidson J Ind Eng Chem 1921 13, 303 

Janeeke Zeitsch angew Chem 1921 34, 542, compare howe\er Janeeke, ibid 
1920 33 278 

7 Janeeke ibid 1920 33, 278 

8 Schiff Annalen 1858 107 83 

9 Gossner Zeitsch Kryst Mm 1904 39 381 

10 Link CreWs chem Ann 1796 i , 26 

11 Mitscherhch Pogg Annalen 1836 39 195 4nn Mine* 18o7 [5] 12 38 (but 
compare Schiff, Annalen 1858 107 83 Johnson and Chittenden -imet J bci li>7s 
[3] 15 131) dAns Zeitsch anorg Chem 1913 80 235 

1 Kendall and Landon loc cit Janeeke Zeitsch angew Chem 1921, 34 o42 

13 Janeeke loc cit 

14 Schulze Ber 1884, 17, 2705 15 Weber ibid 2497 

16 Berthelot Compt rend 1892 114 876 Elbs J pmtt Chem 1893 [2] 48 183 

17 Mullei and Friedberger Zeitsch Elektrochem 1902 8,230 Kunboitmm fur tlrktio 
chemische Industrie German Patent 1908 No 195811 

18 Fock Zeitsch Kryst Mm 1893 22 29 

19 Maishall Trans Chem Soc 1891 59 777 

Elbs and Schonherr Zeitsch Elektrochem 1894, I, 417, 468 189o 2 162 24o 

1 Elbs and Neher, Chem Zeit 1921 45 1113 

22 Malaqum J Pharm Chim , 1911 [7] 3 329 

23 Seyewitz and Trawitz Compt rend 1903, 137, 130 

VOL II 15 



234< ON CARBONE OR CHARCOAL 

diffused through the former, and this mixture 
constitutes the principal part of the atmosphere, 
and is suited, as we perceive, both for animal 
life and combustion 

5 Azotic gas is not affected by repeated 
electrification 



SECTION 4 

ON CARBONE OR CHARCOAL 

If a piece of wood be put into a crucible, 
and covered with sand, and the whole gra- 
dually raised to a red heat, the wood ii> de- 
composed, water, an acid, and se\eial elastic 
fluids are (^-"i^agi J, particularly carbonic 
acid, carburetted hydrogen, and carbonic oxide 
Finally, there remains a black, brittle, porous 
substance in the ciucible, called chmuwl, 
which is incapable of change by heat in close 
vessels, but burns in the open air, and is con- 
verted into an elastic fluid, cai borne acid 
Charcoal constitutes from 1 r > to 20 per cent of 
the weight of the wood from which it uas 
derived 

Charcoal is insoluble in water , a is without 
taste or smell, but contribute much to correct 
putrefaction in animal substances It is less 
liable to decay than wood by the action of air 



AMMONTOH 

Ammonium tetrathionate, (NH 4 )2S 4 O 6 The tebcathionate is pro- 
duced by the action of sulphur dioxide on an aqueous solution of 
ammonium sulphide * 

(XH 4 ) 2 S+3S0 2 =(NH 4 ) 2 S 4 O e 
In aqueous solution it decomposes m accordance with the equafaott * 

(NH 4 ) 2 S 4 6 =(NH 4 ) 2 S0 4 +S0 2 +2S 

Ammonium thiosulphate reacts with it, forming ammonium sulphate 
and liberating sulphur 

2(NH 4 ) 2 S 2 3 +(NH 4 ) 2 S 4 6 =3(NH 4 ) 2 S0 4 +5S 

Ammonium selenide, (NH 4 ) 2 Se Excess of ammonia reacts with 
hydrogen selemde to form ammonium selemde as a white mass s It i$ 
also produced in the form of black, orthorhombic crystafe by $a- 
centrating in vacuum over sulphuric acid aa aqueous solution of 
ammonium molybdate and ammonia saturated with hydrogen seieoide, 
the dark colour being probably due to slight decomposition 4 
exposure to air it gradually decomposes, with liberation of 
selenium It dissolves in water, forming a red solution from 
metallic salts precipitate the corresponding selemde Its heat of forma- 
tion from its elements in dilute solution is 44 6 Cal * 

Ammonia unites with excess of hydrogen selemde to form ammonium 
hydrogen selemde, NH 4 SeH, the heat of formation of the solid compound 
from its elements being 28 9 Cal 5 

Ammonium selemte, (NH 4 ) 2 Se0 3 Concentration of an alcoholic or 
aqueous solution of selemous acid saturated v~ ^ n i 

selemte m four-sided columns or laminae 6 Or 
with separation of selenium, and evolution of niuogcii 

Ammonium selenates On evaporation, a solution of selenic acid 
saturated with ammonia yields the normal selenate, (NH 4 ) 2 Se0 4 , m mono- 
clinic 7 crystals At 7 C its solubility is 117 grams m 100 grams of 
water 8 When gently heated, the normal salt is com erted into 
ammonium hydrogen selenate, NH 4 HSe0 4s 9 of density 2 162 10 

Several complex selenate derivatrves have been described n 

ISOMORPHISM OF THE ALKALI-METAL SULPHATES 
AND SELENATES 

The normal sulphates and selenates of the alkali metals, R 2 S[Se]O 4 
where R represents potassium, rubidium, or cesium, form excellent 
crystals belonging to the rhombic system , and these salts furnish one 

1 Hurdelbimk J Qatbeleuchtung 1910 53 956 

2 Paepe Bull Soc chim 1912 26 244 

3 Bineau, Ann CMm Phys 1838 67 230 68 43o 1839 70 261 

4 I enher and Smith J Amer Chem Soc 189S, 20 277 

5 labre Compt rend 1886 103 269 

6 Muspratt Annalen 1849 70 275 

lopsoe Sitzungsber K Alad Wiss Wien, 1872 66 18 Retgcrs Zcii^cli jJtyoiJal 
Chem 1891 8 6 Tutton Trans Ch<>in Soc 1906 89 10oO comjMrc I nip **tt unq bcr 
K Akad Wiss Wien, 1862 45 108 Rammelsberg, Handbuch da Lry \taUoy) ajilnsclt 
PJiysilalischen Cheime, Leipsic, 1881-1882 I, 497 

8 iutton loc cit 

9 Cimeron and Davy Chem hews, 1878 38 133 

10 Topsoe loc cit 

11 Retgers, loc cit , Weinland and Barttlmgck Ber 1903 36 1397 On ammonium 
tellunte compare Lenher and Wolensky J Amer Chem Soc , 1913 35 718 



236 ON CARBONE OR CHARCOAL 

peared an increase of weight of 6 or 7 grams, 
from the acid .unhung with the common air 
in the flask, of less specific gravity , but the 
succeeding increase was not more than 6 
grains, and arose from the moisture which 
permeated the bladder for the bladder 
continued as distended as at first, and finall) 
upon examination was found to contain no- 
thing but atmospheric air Yet carbonic acid 
is stated to be the most absorbable by char- 
coal One of the authors above alluded to, 
asserts that the heat of boiling water is suffi- 
cient to expel the greater part of the gases so 
absorbed Now this is certainly not true, as 
Allen and Pepys have shewn , and most prac- 
tical chemists know that no air is to be obtained 
from moist charcoal below a red heat Hence 
the weight acquired by fresh made charcoal, 
is in all probability to be wholly ascribed to 
the moisture which it absorbs from the atmo- 
sphere , and it is to the decomposition of this 
water, and the union of its elements with char- 
coal, that we obtain such an abundance of 
gases by the application ot a red heat 

It was the ,> v opinion some time 

ago that charcoal was an oxide of diamond, 
but Mr Tennant, and more recently Messrs 
Allen and Pepys, have shewn that the same 
quantity of carbonic acid is obtained from the 



AMMONIUM COMPOUNDS 227 

Ammonium tetrathionate, (NH 4 ) 2 S 4 6 The tetrathionate is pro- 
duced by the action of sulphur dioxide on an aqueous solution of 
ammonium sulphide * 

(NH 4 ) 2 S+3S0 2 =(NH 4 ) 2 S 4 6 
In aqueous solution it decomposes in accordance with the equation 2 

(NH 4 ) 2 S 4 6 =(NH 4 ) 2 S0 4 +S0 2 +2S 

Ammonium thiosulphate reacts with it, forming ammonium sulphate 
and liberating sulphur 

2(NH 4 ) 2 S 2 3 +(NH 4 ) 2 S 4 6 =3(NH 4 ) 2 S0 4 +5S 

Ammonium selemde, (NH 4 ) 2 Se Excess of ammonia reacts with 
hydrogen selemde to form ammonium selemde as a white mass 3 It is 
also produced in the form of black, orthorhombic crystals by con- 
centrating in vacuum over sulphuric acid an aqueous solution of 
ammonium molybdate and ammonia saturated with hsdiogen selemde, 
the dark colour being probably due to slight decomposition 4 On 
exposure to air it gradually decomposes, with liberation of black 
selenium It dissolves in water, forming a red solution from which 
metallic salts precipitate the corresponding selemde Its heat of forma- 
tion from its elements in dilute solution is 44 6 Cal 5 

Ammonia unites with excess of hydrogen selemde to form ammonium 
hydi ogen selemde, NH 4 SeH, the heat of formation of the solid compound 
from its elements being 28 9 Cal 5 

Ammonium selemte, (NH 4 ) 2 Se0 3 Concentration of an alcoholic or 
aqueous solution of selemous acid saturated with ammonia yields the 
selemte in four sided columns or lamina? 6 On heating, it decomposes 
with separation of selenium, and e\olution of nitiogen 

Ammonium selenates On evaporation, a solution of selenic acid 
saturated with ammonia yields the noimal selenate, (NH 4 ) 2 SeO 4 , in mono- 
clinic 7 crystals At 7 C its solubility is 117 giams m 100 giams of 
water 8 When gently heated, the normal salt is com cited into 
ammonium hydrogen selenate, NH 4 HSeO 4 , 9 of densitv 2 162 10 

Several complex selenate denvati\ es ha\ e been described n 

ISOMORPHISM OF THE ALKALI MET \L SULPHA1ES 
AND SELENATES 

The normal sulphates and selenates of the alkali mctils R 2 S[Se]O 4 
where R icpiescnts potassium, lubiditnn, or cTsmrn, foim excellent 
crystals belonging to the rhombic system , anel these salts iuinish one 

1 Huicklbimk J GaMeuchtiuvj 1910 53 9o6 
Paepe Bull Soc chim 1912 26 244 

3 Bmeau Ann Chun Phys 1838 67 230 68 435 I8o9 70 261 

4 Lenher and Smith J Amu Chem /Soc 1898, 20 277 
tabre Compt rend 1886 103 269 

G Muspratt Annalen 1849 70 27o 

lopsoe Sitzungsber K Akad \\iss }} ien, 1872 66 18 Pctui Znt rlt jJnjiln] 
Chen) 1891 8 6 Tutton Txins Ch m Soc 1906 89 1050 c<>mj>m T IHL S</ ?///v bu 
A Alacl Miss Wien 1862, 45 108 Rammelsbeig Handbuch flu A/y^aUot/tajtlt^ch 
PhysiJ ahschen Chemie Leipsic 1881-1882 i 497 

8 i utton loc at 

9 C imeron and Davj CJiem hews 1878 38 133 

10 fopsoe loc cit 

11 Retgers loc cit Wemland and Barttlmgck Bn 1003 36 1397 On am mom inn 
tellunie compare Lenher and Wolensky J Ame) Chem Sue 1913 35 718 



238 <ON SULPHtTR* 



SECTION 5 

ON SULPHUR 

Sulphur or brimstone is an article well 
known , it is an element pretty generally dis- 
seminated, but is most abundant in volcanic 
countries, and in certain minerals A great 
part of what is used in this country is imported 
from Italy and Sicily , the rest is obtained from 
the ores of copper, lead, iron, &c 

Sulphur is fused by a heat a little above that 
of boiling water It is usually run into cylin- 
drical molds, and upon cooling becomes rod 
sulphur In this case the rolls become highly 
electrical by friction they arc remaikabH 
brittle, frequently falling in pieces by the con- 
tact of the warm hand Its specific gravity is 
1 98 or 1 99 

Sulphur is sublimed by a heat more than 
sufficient to fuse it , the sublimate constitutes 
the common fioweis of sulphur The effects 
of the different gradations of heat on sulphur 
are somewhat remaikable It ib fused at 220 
or 228 of Fahrenheit, into a thin fluid , it be- 
gins to grow thick, darker, and viscid at 
about 350, and continues so till 600 or up- 
wards, the fumes becoming gradually more 






* .. -^ tfwwHg 

AMMONIUM COMPOUNDS., 229 Jj 

HX atomic number in passing from potassium to rubidium and theace to rl 
caesium means the addition of a complete shell of electrons to tfee 
structure of the atom of the alkali-metal according to the Lewis-Laag- 
caior version of the atomic-structure theory, or of two complete 
shells according to the Boh^SoogtmerfeH vemoa It has also b^eaa 
shown by W L Bragg that these three alkali-metals occupy tibe 
positions corresponding with the sharp maxima of the curve of atomic 
diameters, which expresses the size of the chemical atoms as revealed 
in the accumulated results of X-ray analyses of crystals , and that 4 
there is a considerable increase in the size of the atom from potassium 
to rubidium, and again from rubidium to caesium, corresponding wttb 
this addition of electrons in one or two shells 

All Tutton's investigations fully confirm one another in the details 
of the measurements of both exterior angles and of interior physical 
constants Their main results may be summamed in the statement 
that the progression in the atomic-sequence number, and its attendant 
progression m the size of the atom, is accompanied by a sraalarly 
definite progression in the characters, external or internal, of the 
crystals of these isomorphous rhombic and monodbmc series, when the 
potassium in the initial salt of the series is replaced by rubidium, and 
the rubidium in turn replaced by caesium This fact has been proved 
definitely for the interf acial angles , for the axial ratios , for the variable 
axial angle of the monoclimc series , for the relative volumes and 
edge-dimensions of the rhombic or monochnic cells of the structural 
space-lattices , for the refractive indices and molecular refractions , 
for the amount of double refraction , for the orientation of the optical 
ellipsoid of the monochnic series, which is free to rotate about the 
symmetry-axis, and does so progressively , for the thermal expansions 
of the rhombic sulphates, which alone were suitable for dilatation 
experiments , and finally, by the X-ray analysis of the sulphates by Sir 
William Bragg' s X ray spectrometer for the absolute dimensions of the 
space-lattice cells, Tutton's peja&ve measifres having been found correct 

An ther CAlHMt UO -> M> Wk> MrtwfliBllflfiYof deeper 
than was at tust appreciated The ammonium salts are 
almost perfectly isostructural (liBRARY rubidium salts, the 

replacement of rubidium atoms by ammonium (^NH 4 ) ladicals iii\oi\in<r 
practically no change in the relative dimensions of the structural cell 
edges Ihis result also lias been confnmed fully by the absolute de 
terminations by X rays for rubidium and ammonium sulphates It 
follows that the valency- volume theory of Pope and Barlow is incorrect, 
since according to that theory the relative volumes of rubidium sulphate 
and ammonium sulphate should be as 1 to 2, the valency volumes being 
12 and 24 respectively Ihe subsequent discovery of the law of atomic 
diameters from the results of X ray analyses has decided the matter by 
showing that size of atom is involved, but that the sizes are not pro- 
poitional to the valencies and aie those expressed in the curve and table 
of atomic diameteis of W L Bragg 

Tutton's mam law of progression of the crystallographic piopeities 
of the salts of these isomorphous series with the atomic numbei of the 
interchangeable alkali metal is m complete agieement with this law of 
atomic diameters, and the two laws may be said mutually to support 
each other To go even deeper, however, the law of progression of the 



240 ON PHOSPHORUS 

essential in sulphur, is derived from the consi- 
deration of the low specific heat of sulphur 
If this article contained 7 or 8 per cent of 
hydrogen, or 50 per cenr of oxygen, or as 
much water, it would not have the low spe- 
cific heat of 19 

Sulphur burns m the open air at the tempe- 
rature of 500 , it unites with oxygen, hydro- 
gen, the alkalis, earths and metals, forming a 
great variety of interesting compounds, which 
will be considered in their respective places. 



SECTION 6 
ON PHOSPHORUS 

Phosphorus is an article having much the 
same appearance and consistency as white 
wax It is usually prepared from the bones of 
animals, which contain one ot its compounds, 
phosphate of lime, by a laborious and complex 
process The bones are calcined in an open 
fire, when reduced to powder, sulphuric acid 
diluted with water is added , this acid takes 
part of the lime, and forms an insoluble com- 
pound, but detaches superphosphate ot lime, 
which is soluble in water This solution is 
evaporated, and the salt is obtained in a glacial 
state The solid is reduced to powder, and 




AivnvromuM OOMPOUNDS. 



can also be produced by the action of nitrogen peroxide o& ammonium 
carbonate, extracting the product with absolute aloojhol, aad pre- 
cipitating the mtnte with ether i y and by a $3J3oaia 
method from an aqueous alcoholic solution of so^U 
ammonium sulphate 2 The methods employed m its preparation 
been summarized by Sorensen x 

Ammonium nitrite crystallizes HI deliquescent* feather-fab 
with a faint yellowish tinge Its beat of formation from its elements 
is 64 8 Cal 3 When heated, either in the solid state or in sohifeoa, it 
decomposes into nitrogen and water 

NH 4 N0 2 =N 2 +2H 2 

For the solid the decomposition takes place between 60 aa$ W <X 
and readily develops an explosive character 4 It is facdsfcsled bj 
acidifying the nitnte 5 The pure salt is said to foe non-explosatve^ 
but to be decomposed in accordance with the equation by heateg at 
100 C in a Hofmann tube 6 The salt is compai?a&vely stable wbea 
kept beneath a layer of alcohol-free ether 

The decomposition of the nitnte in aqueous solution has been the 
subject of many investigations 7 In vacuum at U7 to 40 C, the 
decomposition is very slight , at 70 C it proceeds slowly in accordance 
with the equation, but most of the salt sublimes unchanged When the 
sublimate is heated with a naked flame, it yields nitrogen and up to 
6 per cent of nitric oxide 8 

The decomposition of the nitrite is much accelerated by the catalytic 
action of platinum-black 9 Other catalysts are also said to facilitate 
the reaction 10 

Ammonium nitrate, NH 4 NO 3 The nitrate can be prepared by the 
general methods applicable to the ammonium salts It is also produced 
by heating the nitrate of an alkali-metal with ammonium sulphate at 
160 to 200 C , the fused ammonium nitrate being separated from 
the solid alkali metal sulphate by centnfuging n Another method 
consists in cooling a concentrated solution of sodium nitrate and 
ammonium sulphate to 15 C , sodium sulphate being precipitated 
On evaporation of the mother-liquor, most of the sodium sulphate 
is deposited , addition of nitric acid to the clear solution causes 
crystallization of the ammonium nitrate 12 When sodium nitrate is 

1 Sorensen Zeitoch anoig Chem 1894 7 1 

2 Biltz and Gahl Zeitsch fflekttochem 1905 n 409 

3 Berthelot Ann Chim Phys , 1880 [5], 20 2o5 

4 Berthelot, Compt rend 1874 78 102 

5 Sorensen loc c^t 

6 Neogi and Adhicary Trans Chem Soc 1911,99 116 

7 Berzelius Gilbert s Annalen 1812 40 206 Coremunder 4m? Chim Phy* 1849 
[3] 26 296, Millon ibid 1847 [3] 19 2o5 Bohhg InnaUn Ibb3 125 21 \ngeh 
and Boens, Atti R Accad Lincei Ib92 [5] I n 70 Ca~~ettu 1M)2 22 n 349 \\eg 
scheider Zeitsch physilal Chem 1901 36, o43 Aindt ibid 1902 39 64 1903 45 570 
Blanchard ibid 1902 41 681 1905,51 117 \eky Ttans Chem boc 1903 83 736 
Berger Bull Soc chim , 1904, [3] 41, 682 , Biltz and Gahl Zeihch Elektrochem 1905, 
ii 409 

8 Ray Trans Chem Soc 1909 95 345 

9 Vondra6ck Zeitsch anorg Chem 1904 39 37 

10 Arndt loc nt Blanchard loc cit Vcley P>oc Roy Soc IhbS 44 239 PM 
Ttan* 1888 179 257 Low Ber 1890 23 30J8 

11 Roth German Patent Bo 1890 23 (Referate) 714 

12 Benker Chem Zeit 1892 654 compare Groendahl and Lindin Mon Scient 
1893 [4],7,u,257 



242 OK THE METALS 



SECTION 7 

ON THE METALS 

The metals at present known, amount at 
least to 30 in number , they form a class of 
bodies which are remarkably distinguishable 
from others m several particulars, as well as 
from each other 

Gravity One of the most striking pro- 
perties of metals is their great weight or specific 
gravity The lightest of them (excluding the 
lately discovered metals, potasiurn and sodium) 
weighs at least six times as much as water, and 
the heaviest of them 23 times as much On 
the supposition that all aggregates are consti- 
tuted of solid particles or atoms, each sur- 
rounded by an atmosphere of htat, it is a cu- 
rious and important enquiry, whether this su- 
perior specific gravity of the metals is occa- 
sioned by the greater specific gravity of their 
individual solid particles, or from the greater 
number of them aggregated into a given vo- 
lume, owing to some peculiar relation they 
may have to heat, or their ^upenor attraction 
for each other Upon examination of the facts 
exhibited by the metak, in their combinations 



AMMONIUM. COMPOUNDS. 

The density of ammonium nitrate is 1 709 * 1 W3 a at 2 C , 
1 725 3 at 15 C , and 1 725 * at 20 C Its^e&fc <f foraa&oj* feom 
ii^ elements is given as 87 9 Cal 5 and 88 1 Cal 6 , and its spacafie heat 
as 407 between and 81 C 7 Its solubility m water KE grrai ja 
the table 8 

SOLUBILITY OF AMMONIUM MTRATE 



Temperature, 
C 


Density of 
Solution. 


Grams gf 
HH^OS m 100 
grams of Water 


Sofe4Bw*. 







1183 


NH 4 NO 3 rhombic jS 


122 


12945 


1534 


J9 59 >? 


202 


13116 


1924 


* 35 99 


BOO 


13299 


2418 


5> * *? 


32 I 


13344 


2569 


<H-j8 


350 


13394 


2658 


3* >? <* 


40 


13464 


2970 


35 9? 


50 




344 


33 53 


60 




421 


39 9 53 


80 




580 


33 J9 39 


100 




871 


rhombohedral ? 



When heated, ammonium nitrate first melts, then dissociates in accord- 
ance with the scheme 9 

NH 4 N0 3 ^ NH 3 +HN0 3 , 

and commences to evolve a gas containing 98 per cent of nitrous 
oxide, 9 the reaction beginning at 185 C 10 

NH 4 N0 3 ==N 2 0+2H 2 0+29 5 Cal 

This gas always contains free nitrogen, nearly 2 per cent being piesent 
up to 260 C , and considerably more at higher temperatures 9 

5NH 3 + 3HNO 3 = 4N 2 + 9H 2 O 

Tiaces of mtiogcn pei oxide and of nitric oxide ait ah\a\s piesuit, the 
piopoition of each between 220 and 260 C a\eragmg 001 pei eent 
Ihc evolution of gas incieases ^ith use of tempeiatme, and is steady 
up to 250 C At higher temperatmes it becomes spasmodic, and 

1 Schift Annalen 18o8 107 59 1859 ill 80 

2 bohiff and Monsacchi Zeitsch physikal Chem 1896, 21, 277 

3 Rctgers ibid 18h9 4 592 

4 Haigh J Avna Chem Soc 1912 34 1137 

5 Berthelot Ann Chun Phy* I860 [5] 20 2oo Compt tend IbbO 90 779 Bull 
&oc cJmn , 1880 [2] 33 509 

6 Thomsen, J prakt Chem 1880 [2] 21 440 

7 Bellati and Komanese Ann Phy&iL Beibl Ibb7 n 520 Atti In&t 1 en ISbG [b] 
4 1395 

8 Mullei and Kaufmann ZeitscJt phytikal Chem 1903 42 497 taken fiom beidtll 
Solubilities of Inorganic and Organic Substances (Ciosby Lockuood ^ Son 1911) 

9 Saundois, Trans Chem Soc 1922 121 698 

10 Pickeimg Chem J\ ews, 1878 38 267 \ele>, Tran* Chem Soc , 1883, 43 370 
compare Berthelot, Compt rend , 1876 82 932 



244 GENERAL PROPERTIES OF THE METALS. 

if this be great, the heat is partly expressed or 
squeezed out , but if little, it is retained^ 
though the attraction ot the particles for heat 
remains unaltered An atom of water may 
have the same attraction for heat that one of 
lead has , but the latter may have a stronger 
attraction of aggregation, by which a quantity 
of heat is expelled, and consequently less heat 
retained by any aggregate of the particles 

Opacity and Lustre Metals are remark- 
ably opake, or destitute of that property which 
glass and some other bodies possess, of trans- 
mitting light When reduced to leaves as 
thin as possible, such as gold and silver leaf, 
they continue to obstruct the passage of light 
Though the metallic atoms, with their atmo- 
spheres of heat, are nearlv the same size as the 
atoms of water and their atmospheres, yet it 
seems highly probable that the metallic atoms 
abstracted from their atmospheres, are much 
larger than those of wate*- in like circumstances 
fhe former, I eonceive, are large particles 
with highly condensed atmospheres , the lat- 
ter, are small particles with more extensive 
atmospheres, because of their less powerful 
attraction for heat Iltnee, it may be sup- 
posed, the opacity of metals and their lustre 
are occasioned A great quantity of solid 
matter and a high condensation of heat, are 




Ammonium hypophosplute^NH^aPQa^lte^^ 

* obtained by mixing solutions of barium hypophosphite and ammonium 
sulphate yields a residue from which alcohol extracts ajBiaoffiium 
hypophosphite, hexagonal 1 laminae or rhombic 2 plates, agdNaoag at 
100 C When heated above its melting-point it is converted 
spontaneously inflammable phosphine, ammonia, and water, 

Ammonium phosphites Excess of ammonia 

acid to form secondary ammomwn pkospktfe> (NB.^)JSfO 39 evaporation, 
of the solution over sulphuric acid yielding the salt u* four-sided 




-0* 



2(f 30 40 
Temperature 



50 



70 



FJQ 12 Solubility of ammonium nitrate, of potassium nitrate, and of their acid 
salts in nitric acid and of the trimtrates in water 

columnar crystals of very deliquescent character 3 It is also pioduced 
by the action of ammonia on the primary salt at 80 to 100 C , 4 or on 
phosphorous oxide in presence of water It readilv loses ammonia and 
watci, and strong heating produces phosphme and phosphouc acid 3 

Pnmaiy ammomwn phosphite, NH 4 H 2 P0 3 , can be prepared from 
phosphoious acid by addition of sufficient ammonia to change the coloui 
of methyl orange 4 On concentiatmg the solution it separates in mono 
clinic prisms, melting at about 123 C At 145 C it e\ohcs ammonia, 
and at higher temperatures phosphme Its solubilit} at 14 5 C is 
190 grams in 100 grams of water 4 At 100 C it is decomposed b} 
water, with hbeiation of ammonia 5 

Ammonium hypophosphates Excess of ammonia comcrts h>po- 
phosphoric acid in solution into normal ammonium hypopho&phate, 

1 Wurtz Ann Chim Phy* 1843 [3] 7 193 

2 Beckenkamp Zeihch Kryst Mm 1903 37 018 

3 Rose, Pogg Annalen 1828 12 85 

4 Amat Compt rend, 1887, 105 809 

5 Dufet Bull Soc fran$ Mm , 1892 14, 206 



3i6 GENERAL PROPERTIES OJF 1HE METALS. 

Metals combine with various portions of 
oxygen, and form metallic onde* 9 they also 
combine with sulphur, and form *ulphuiet$ 9 
some of them with phosphorus, and form piws- 
phinets > with carbone or charcoal, and form 
carburets, Sec which will be treated of in their 
respective places Metals also form compounds 
one with another, called alloys 

The relatue weights of the ultimate particles 
of the metals may be investigated, as will be 
shewn, from the metallic oxides, from the me- 
tallic sulphurets, or from the metallic salts , 
indeed, if the proportions of the several com- 
pounds can be accurately ascertained, I have 
no doubt they will all agree in assigning the 
same relative weight to the elementary particle 
of the same metal In the present state of our 
knowledge, the results approximate to each 
other remarkably well, especially uhere the 
different compounds have been examined with 
care, and can he depended upon , but the pro- 
portions of the elements in some of the metallic 
oxides, sulphurets, and silts, have not yet been 
found with any degree, of precision 

The number of metals hitherto discovered is 
30, including the two derived Irom the fixed 
alkalis, some of these miy, perhaps, be im 
properly denominated metals, as the} are 
scarce, and have not been subjected to so much 




AMMONIUM COMPOUNDS. 



to the monoclimc system, 1 with a saline, ammomacal taste, and density 
1 554 a It loses ammonia readily, aad is converted by heat into 
secondary sodium phosphate Wliea heated with metallic sails it 
forms vitreous " nucrocosmic beads " of characteristic colo i ur, a&d is 
employed in qualitative analysis 

Potassium Awmmowwm phosphate, KfNB^JaPQi^H^O, is obtained 
by passing ammonia into a cooled solution of potassmru 
phosphate, and filtenng rapidly m an atmosphere of ammonia, 
exposure to air, the deliquescent salt evolves ammonia, but it e 
preserved in sealed tubes 8 Other double salts wjtli scK&um, 4 aad 
hthium 5 and potassium, 6 have been prepared 

Ammonium pyrophosphates Excess of ammonia reacts with 
pyrophosphonc acid to form normal ammonium pyrophogphdte, 
(NH 4 ) 4 P 2 O 7 , precipitated from aqueous solution by addition of akoboL 
It forms crystalhne laminae, dissolving very readily in water to a solution 
of alkaline reaction 7 When boded, this solution evolves ammonia, 
yielding an acid solution x of secondary ammowwm pyrophosphate, 



Double pyrophosphates with sodium 8 and with potassium 9 have 
also been described 

Ammonium metaphosphates Several metaphosphates are known, 10 
among them ammonium monometaphosphate, NH 4 PO 3 , formed from 
the dimetaphosphate by prolonged heating at 200 C u It is only 
slightly soluble in water 

Ammonium arsenites Between 70 and 80 C ammonia reacts 
with a solution of arsemous oxide to form acicular crystals of aminonium 
meta-arsenite, NH 4 As0 2 12 With concentrated ammonia arsemous oxide 
yields the crystalline ammonium pyroarsenite, (NH 4 ) 4 As 2 O^, an unstable 
substance decomposed with evolution of ammonia on exposure to air ^ 

Ammonium arsenates Excess of ammonia precipitates normal 
ammonium arsenate, (NH 4 ) 3 AsO 4 , from concentrated solutions of the 
primary and secondary salts It yields a very alkaline solution, de 
composed by zinc and by aluminium with evolution of h}drogen and 
arsme 14 Secondary ammonium arsenate, (NH 4 ) 2 HAs0 4 , is gradually 
deposited from a concentrated solution of arsenic acid and ammonium 
hydroxide 15 Loss of ammonia, or addition of arsenic acid to its solution, 
converts it into primary ammonium arsenate, NH 4 H 2 \sO 4 , crystals of 
density 2 307 16 or 2 3105 17 

1 Thomson and Bloxam Trans Chem Soc 1882 41 379 

2 Schifif Annalen 1859, 112 88 

3 Corelh Oazzetta 1921 51 n 380 

4 Uelsmann Arch Pharm 1859 [2] 99 138 Herzfeld and Feuerlem ZeitscJt anal 
Chem 1881 20 191 Meslm Compt rend 190o 140 7h2 

5 Berzelms Lehrbuch der Chemie, 3rd ed Dresden 1833-1841,4 213 

6 JMhol and Senderens Compt rend 1882 94 649 

7 Schwarzenberg Annalen 1848 65 141 

8 Schwarzenbeig loc cit Rammelsberg 'inn Phyt>iJ 1883 [2] 20 94S 

9 Schwarzenberg loc cit Retgers Zettsch physiJ al Chem 1894 15 520 

10 Compare metaphosphonc acid this series \ ol \ I 

11 Meitmann Pogg Annalen 1849 78 233 238 
1 Luynes J pralt Chem 1857 72 80 

13 Pasteur Annalen 1848 68, 308 Stem ibid 1850 74 218 

14 Smith J Soc Chem Ind , 1904 23 475 1911 30 253 

15 Salkowsky J prakt Chem, 1868 104, 129 

16 Schroder, ibid , 1879 [2] 19 266 

17 Muthmann, Zeitsch Kryst Mm , 1894, 22, 497 



248 GEMRAL PROPERTIES OF THE METALS 

4 Refractory 

1 Titanium 3 Tantahum 

2 Columbmm 4 Cerium 

To which last class also may the supposed 
metals from the earths be referred 

The following Table exhibits the chief properties of the 
metals in an absolute as well as comparative point of 
view 



Metals 

Gold 
Platm 
Silver 
Merc 
Pallad 
Rhocl 
Ind 
Osm 
Copper 
lion 
Nickel 
Tin 
Lead 
Zmc 
Potas 
Sodium 
Bism 
Antmi 
Tellui 
Arsenic 
Cobalt 
Mang 
Chrom 
U.an 
Moljb 
lungs 
Titan 
Colum 
Tontal 
Cumm 


Colour 


Hard 
ness 


Sp Gr 


Wt ofult 
particles 


Melting 
point 


Tena- 

city 

1^0 
271 

1S7 


yellow 
white 
white 
white 
white 
white 
white 
slue 
red 

F*y 
white 
white 
blue 
white 
white 
white 
red wh 
grej,u 
blue w 
blue w 
grey 

g^y 

yd w 
iron efi 
yel w 
grey w 
ifd 


6 
75 
05 


9 


19362 
2300 
10511 
13580 
11 871 
11 + 


140? 
100? 
100 
167 


32 W 
170*+W 
22 W 
39 F 
160+W 
160+\V 
100+W 
ir)0 + W 
27o XV 
!5S a \\ 
160+W 
H0 p F 
012 Q F 
680 } 
bO 1 
150 p 
H6 F 
S10 U 1 
012 C +I 
4()0 U + I 
1 iO<- \\ 
100* \\ 
170 W + \V 
170^4-^ 
17U^ + \\ 

17() W 4-^ 
170 4-NV 
170 +\\ 
170 +\V 

1*7^ i \\ r 
















8 
9 
8 
6 
5 
6 

1 
6 
65 


8 878 
7 788 
8 666 
7 SOO 
11 352 
7 190 
600 
Qi5 
9 823 
6 800 
631-3 
8 31 
7 811 
7 000 


56 
50 
2:>? 50? 
50 
95 
50 
^5 
'21 

OS? 

40 


302 
550 

31 
IS 
Ib 

20 

7 


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9 000 
7 500 
17 6 


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whit.r 






A-I? 





AMMONIUM 

1 573 * and I 544 2 at 15 C Its solubility a| 17 1 is 19 3 giaeas m 
100 grams of water, 2 the salt crystallizing wefi feona aqueous solution 
It is a product of the decomposition of the normal carbonate at orxiinary 
temperature 3 

A tetra-ammomum ckkydrogen oaarbonate, {NH^H^CO^HsO, can 
be prepared by heating the commercial salt to fusion, and aBkywiog the 
liquid to solidity 4 , by crystallizing the commercial salt from warm 
ammonium hydroxide 5 ; and by the action of alcohol OB tte normal 
salt 6 It forms rhombic plates antd prisms, soluble m 5 times their 
weight of water at 15 C Its properties are intermediate between tbo&e 
of the normal carbonate and the primary carbonate, and it is doubtful 
whether it is a definite compound or a mixture of these two salts 

Commercial ammonium carbonate is a .mixture of ammonium hydrogen 
carbonate and ammomum carbamate, NH 2 CO ONH^ and is probably 
a definite compound of the two salts 7 It is formed by dtstdiation of a 
mixture of ammonium chlonde with carbonate of potassium, sodium, or 
calcium, and was formerly manufactured by the dry distillation of 
animal excrement, horn, and other substances It is now obtained as a 
by-product of the gas-manufacture, and after sublimation condenses in 
hard lumps 

Ammonium cyanide, NH 4 CN The cyanide is manufactured by 
passing ammonia alone or mixed with hydrocarbons 8 over red-hot 
coke , or by heating ammonia with carbon monoxide 

2NH 3 +C=NH 4 CN+H 2 , CO+2NH 3 =NH 4 CN+H 2 , 

or by passing a mixture of ammonia, hydrogen, and nitrogen over coke 
at 1100 C 9 It is also a by-product in the manufacture of coal-gas, 10 
and is formed by the interaction of ammonia and calcium carbide at 
650 C n Other methods of formation are the combination of methane 
and nitrogen under the influence of the silent electric discharge, 12 and the 
distillation of ammonium chloride with anhydrous cyanides 13 

Ammomum cyanide forms colourless cubes, readily volatilized and 
completely dissociated at comparatively low temperatures 14 Its heat 
of formation from diamond, hydrogen, and nitrogen is 3 2 Cal 15 It 
dissolves readily in both water and alcohol, the salt being extensively 
dissociated in aqueous solution It is extremely poisonous 

Ammonium thiocyanate, NH 4 CNS The thiocyanate is manu 

1 Schiff Annalen, 1858 107 64 

2 Dibbits J prakt Chem 1874, [2] 10 434 

3 Divers J Chem Soc 1870 23 171 359 364 Deville Ann Chun Phys 1854 
[3] 40 87 J praU Chem 1854 62 22 Vogler Zcittch anal Chem Ib78 17 4ol 

4 Rose Pogg Annalen 1839, 46 400 

5 Deville loc cit 

6 Divers loc cit 

7 Compare Dibbits loc cit 

8 langlois Berzehus s Jahresbencht 1822 84 compare Bergmann J Ga&beleuchtung 
1S96 39 117 140 

9 Lance Compt rend 1897 124 819 

10 Penchie J Qasbeleuchtung 1888 31 1006 

11 Salvadori Gazzetta 1905 35 i 236 

1 Figuier Compt rend 1886 102 694 

1 3 Bmeau Annalen 1839 32 230 

14 Bmeau loc cit Ostwald Lehrbuch der allgememen Chemw 1st cd Leipsic ISSo- 
1887 2,687 Deville and Troost Compt rend 1859 49 239 It>(j3 56 b91 4wwa/c/j 
1860, 113 42, 1863 127,274 

15 Berthelot, Compt rend , 1880, 91, 79 



250 GOLD PLATINA 

ing reduced to ^th of that thickness on silver 
wire Gold melts at 32 of Wedgwood's py- 
rometer , that is, a red heat, but one greatly 
inferior to what may be obtained by a smith's 
forge when fused, it may continue in that 
state for several weeks without losing any ma- 
tenal weight There is reason to believe that 
gold combines with oxygen, sulphur, and 
phosphorus , but those compounds are diffi- 
cultly obtained It combines with most of 
the metals, and forms alloys of various de- 
scriptions 

The weight of an atom of gold is not easily 
ascertained, because of the uncertainty in the 
proportions of the elements forming the com- 
pounds into which it enters It is probably 
not less than 140, nor more than 20O times the 
weight of an atom of hydrogen 

PLATINA This metal has not been found 
any where but in South America In its crude 
state, it consists of small flattened grains of a 
metallic lustre, and a grey-white colour 1 his 
ore is found to be an alloy of several metals, 
of which platina is usually the most abundant 
The grains are dissolved in nitro-muriatic acid, 
except a black matter which subsides , the 
clear liquor is decanted, and a solution of sal 
ammoniac is dropped into it a yellow preci- 
pitate falls , this is heated to redness, and the 




AMMONIUM COMPOUNDS. 

crystals 1 of the pentaborate, (NH 4 ) 2 O 3 5B 2 O s ,8H ft O, soluble m 8 times 
their weight of cold water 

The mineral larderelhte, (NH^O^BaO^SHjp, is found in nature im 
association with bone acid nx the lagoons of Trosaay* 

Ammono-salts of tbe Alkali-metals The mte!&<xm of metai&c 
amides in ammonia solution produces the so-called <mm<m&~$8M$ * 

DvpotasMum ammonosodutfe, (Na[NH 2 ] 3 )K 2 , is formed fey tbe section 
of potassamide on sodamide in solution ni liquid ammonia, fey bunging 
sodium iodide into contact with excess of potassamide clissofved im 
hquid ammonia, and by the interaction in presence of a suaall pro- 
portion of platinum-black of sodium and a solution of potassaoaide 10 
liquid ammonia This substance forms well-developed crystals, and is 
stable in vacuo at 100 C , but at higher temperatures it melts with 
evolution of ammonia, and attacks glass 

Monorubid/ium ammonosod/icde, (Na[NH2~j 2 )Hb, is the product of tiie 
simultaneous action of sodium and rubidium on liquid ammonia It is 
soluble in this solvent, and is energetically decomposed by water with 
formation of sodium and rubidium hydroxides Its solution m liquid 
ammonia is converted by a large excess of rubidium into d&rttfackum 
ammonosodiate, (Na[NH 2 ] 3 )B.b2, a substance much more soluble in 
liquid ammonia than its parent compound 

D^potass^um ammonohthiate, (LifNH^Kg, is formed from potass- 
amide and lithium iodide in solution in liquid ammonia, and under 
the influence of platinum-black by the simultaneous action of potas- 
sium and lithium on liquid ammonia The very small, colourless crystals 
are almost insoluble in liquid ammonia With acid amides, ammonium 
hahdes, and ammonium salts of oxy-acids it yields the corresponding 
salts of lithium, potassium, and ammonium 

Monorubid/ium ammonohthiate, (Li[NH 2 ] 2 )Rb, is prepared by the 
action in presence of platinum-black of lithium on rubidamide dis 
solved in liquid ammonia The white crystals are sparmglv soluble 
in liquid ammonia, and are decomposed analogously to those of the 
dipotassium derivative 

1 Atterberg Zeitsch anorq Chem 1906 48 371 
Franklin, J Physical Chem 1919, 23, 36 



VOI II 



252 SILVER 



oxygen, it should seem to be about 100 , but, 
judging from its great specific gravity, one 
would be inclined to think it must be more. 
Indeed the proportion of oxygen in the oxides 
of platina cannot be considered as ascertained 

Platma is chiefly used for chemical pur- 
poses 3 in consequence of its infusibihty, and 
the difficulty of oxidizing it, crucibles and 
other utensils are made of it, in preference to 
every other metal Platma wires are extremely 
useful in electric and galvanic researches, for 
like reasons 

SILVER This metal is found in various parts 
of the world, and in various combinations , 
but the greatest quantity is derived from Ame- 
rica Its uses are generally known The 
specific gravity of melted silver is 10 4^4 , after 
being hammered, 10511 English standard 
silver, containing T ' r copper, simply fi^ed, is 
102 Pure silver is extremely malleable and 
ductile , but inferior in these respects to gold 
It melts at a moderately red heat It is not 
oxidized by exposure to the air, but is tar- 
nished or loses its lustre, which is occasioned 
by the sulphureous vapours floating in the air 
It unites with sulphur in a moderate heat , 
and may be oxidized by means of galvanism 
and electricity , it burns with a green flame 




C0PPUR. 



vases of Cyprian ongin dating from the s&xm paciod la&Te bem found m 
EgTp* The metal employed m tfaesr manufacture -was free feona tea, 
f pEe great metallurgical skill possessed by tibe makers of these vessels 
proves that copper nmst have l>e$& fowwii m Cyprus for many esatarifcs 
previous to their production 

Copper daggers found m Northern Italy probably dale from 
the year 2100 B c x Keith 2 |^ve$ the date 2000 B a for the 
of the Bronze Age in Britain, five centuries later than the date 
by Montelms 3 Copper was probably known ra China about the 
3000 B c There is evidence of its havmg been worked m India at an 
early penod 

The association of the ores of copper with those of other mefcats is 
probably the cause of the production of alloys of varying compositsom 
by the prehistoric smelters The earhest copper took of Britain contain 
tin , those of Hungary up to 4 5 par cent of aixtimo&y 4 

Chinese and Japanese bronze mirrors dating from the first, fifth, 
seventh, eleventh, and twelfth centuries have been found to contain 
between d2 and 74 per cent of copper associated with other metals A 
Corean mirror of the tenth century contains 78 per cent of copper, and 
considerable proportions have been found in ancient coins, arrow-heads, 
and water-pots from these lands 5 

Copper deposits in Britain are said to have been known to the 
Phoenicians about the year 1000 B c In 1581 mining was being 
earned on at Keswick, m Cumberland, the ore being probably a sulphide 
The Mines Royal Society established a works for copper-smelting at 
Neath, in Wales, in 1584 Various other works were started in Wales 
at different times, notably those erected by Lane and Pollard at Swansea 
in 1717 

The production of copper in Cornwall and Devori continued from the 
time of Queen Elizabeth to the end of the nineteenth century In 
Ireland the industry was carried on from the beginning of the eighteenth 
century until 1880 The copper of Anglesey was known to the Romans, 
and the mines of the island were worked during the eighteenth and nine- 
teenth centuries 

Reveiberatory furnaces were constructed by Lambert in Chile m 
1842, and the first blast furnace was erected by him m that country 
m 1857 So successful was the development of this enterprise, that Chile 
became the world's largest producer in the years 1861 to 1870, and 
furnished about half the total output The decline of the \\elsh 
industry dates from this period, and also the de\ elopmcnt of the manu 
facture in the United States of America, Calumet, m the Lake Suptnor 
district, becoming an important centre The next decade is noted for 
the inception of copper-mining in Spain and Portugal, the chief centies 
being the Andalusian, San Domingo, Tharsis, and Rio Tmto mines 

Between 1881 and 1890 the United States of Ameiica became the 
greatest producer, manufacturing one third of the \\ orld s output In 
addition to the Lake mines, works were begun m Montana and Arizona 

1 Montelms, J Anthropol Inst 1897, 26 258 

2 Keith, Presidential Address to the Royal Anthropological Institute January 26 
1915 

3 Montelms Archeologia 1909, 61 162 

* Compare Berthelot Compt rend 1893 116 161 1894 118 764 1897 124 328 
Ann Chim Phys 1889 [6] 17 508, Coffey J Anthropol Inst 1901 31 2G5 
5 Chikashige, Trans Chem Soc , 1920 117 917 



254 PALLADIUM RHODIUM 

smell, it may be taken internally, without 
producing any remarkable effect on the human 
body It can be united with oxygen, sulphur, 
and phosphorus, and it forms alloys, or, as 
they are more commonly called, qmalgam$> 
wtf h most of the metals 

The weight of an atom of mercury is deter- 
minable from its oxides, its sulphuret, and the 
various salts which it forms with acids from 
a comparison of all which, it seems to be about 
167 times the weight of hydrogen From any 
thing certainly known, the mercurial atom is 
heavier than any other , though there are two 
or three metals which exceed it 10 specific 
gravity 

PALLADIUM This metal was discovered a 
few years ago in crude platina, by Dr Wollas- 
ton, of which an account may be seen in the 
Philos Transact for 1804 Jt is a white 
metal, resembling platma in appearance, but 
is much harder it is only one halt of the spe- 
cific gravity ofr phtina It require^ great heat 
to fuse it, and is difficultly oxidized Palla- 
dium combines with oxygen and sulphur, and 
forms alloys with seveial ot the metals But 
we have not yet sufficient data to determine 
the weight of its ultimate particles 

RHODIUM This metal has been discovered 
still more recently than the last in crude pla- 




The German or Swedish process involves five steps . (1) roasting tbe 
ore, (2) smeltag the roasted ore to matte in a blast fomaee; (3) roasting 
the matte , (4) smelting the mstie in a blast furnace mt& oofce and 
fluxes to black-metal or coarse-metal ; (5) Defining the coarse-metal 
Dtumg the process the sihceous material and part of tbe iron are con- 
verted mto a fused silicate-slag, floating on a heavier layer of copper 
matte consisting of a fused mixture of cuprous solplade and fesroos 
sulphide The reduction to copper is effected ebidiy fey carbon 
monoxide or carbon, and not by the sulphur present. To concentrate^ 
the matte, the cycle of oxidation by roasting and reduction fey scaeHaog 
is repeated several tunes, the iron being gradually removed as a fesod 
slag of ferrous silicate 

The English process comprises six operations, (1) calcination, 
(2) smelting to matte in a reverberatory furnace , (8) roastag tibe matte ; 
(4t) smelting the matte in a reverberatory fornaee to wfafametal or 
fine-metal , (5) conversion of the fine-metaJ mto coarse-eopper or Sl&s&r- 
copper, sometimes after a preliminary calcination , (6) refining the coarse- 
copper In this process the calcined ore is smelted in a reverberatory 
furnace, the reduction being effected by the interaction of the sulphides 
and oxides or sulphates, with evolution of sulphur dioxide, thus yielding 
a more concentrated matte than the blast-furnace process 

Cu 2 S+2Cu 2 O==6Cu+S0 2 , 

Cu 2 S+2CuO==4Cu+SO 2 , 

Cu 2 S+CuSO 4 =3Cu+2SO 2 

The siliceous lining of the hearth converts the ferrous oxide mto a slag 
of ferrous silicate By altering the air-supply to the furnace, the matte 
is subjected to alternate oxidation and reduction Both the German 
process and the English process depend on the fact that copper has a 
greater affinity for sulphur than for oxygen, and iron a greater affinity 
for oxygen than for sulphur 

The Welsh process differs from the English method in the enrich 
ment of the matte by smelting with copper slags formed in subsequent 
operations 

The Anglo German process is a combination of the English and 
Geiman methods After calcination the ore is smelted in a shaft 
furnace, and the matte is concentrated in a reverberatory furnace The 
subsequent smelting to coarse metal can be effected m either type of 
furnace 

The concentration of the matte and its subsequent smelting to 
coaise-copper aic also effected by the Bessemer process, a modified t}pe 
of Bessemer converter with the side tuyeres raised about 10 inches abo\e 
the bottom lining being employed The process finds evtensi\e appli- 
cation, a large propoition of the arsenic and antimony being eliminated 
A seiious item of expense is the iene\\al of the siliceous lining of the 
converter, the silica required for slagging the iron being prowded fiom 
this source 

In localities wheie fuel is expensive, pyntic smelting 1 has been 
considerably developed It was devised by John Holway 2 in 1878 

1 Schiffner Rep 5th Internat Congress Appl Chem , 1903 2 102 , Lodin ibid 251 

2 Holway A New Application of Bessemer s Method of Rapid Oxidation by uhich 
Sulphides are utilized as Fuel, Royal Society of Arts, February 1879 



256 COPPER IRON 

weights of the atoms of these two metals are 
unknown 

COPPER This metal has been long known 
It is of a fine red colour , its taste is styptic 
and nauseous Its specific gravity vanes from 
8 6 to 8 9 It possesses great ductility, can 
be drawn into wire as fine as hair, and is ca- 
pable of being beaten into very thm leaves 
It is fused in a temperature higher than silver, 
and lower than gold, about 27 of Wedg- 
wood's thermometer Copper unites with 
oxygen, sulphur, and phosphorus , and forms 
alloys with several other metals 

The weight of the ultimate particle of cop- 
per, may be ascertained w*th considerable pre- 
cision, from the proportions in which it is 
found combined with oxygen, sulphur, and 
phosphorus , as well as from its combinations 
with the acids From a comparison of these, 
its weight seems to be nearly 56 times that of 
hydrogen 

IRON This metal, the most useful we are 
acquainted with, has been long known It 
seems to be found almost in eveiy coun ry, 
and in a great variety of combinations Its 
ores require gieat heat to expel the foreign 
matters, and to rnelt the iron, which is first 
obtained in mabses or pigs, called cast non , 



COPPER. 

polmg is deleterious, causing the reduction of arse&ates and aatamonates 
to the corresponding elements, and thus deteacicaatog tfee quality of the 
eopper The soft, malleable metal is kaowa as tou^hr^ak oopp^ar, and 
displays a lustrous, silky fracture Several vaoetjes of q&j$&c axe 
recognized in the trade bean-shot coppe? is formed fey po^irij^ tibe 
metal mto hot water , fea$hwe&-$hot copper by powmg ifito ^>old tKafer; 
rosette eopper by cooling the surface of t]be fiised sacral W&& wafa@r y 3K*d 
removing the thin, dark red crust formed , j^pcsw eopper by castog xnto 
ingots, and cooling rapidly with water, its colour being purple-red , $5e 
copper, an impure form produced by refining the first tappings ; be&- 
selected copper, a purer type 



(2) WEE METHODS 

Wet methods of extraction are applied to low-gmde ores containing 
not less than 25 to 1 per cent of copper, 03? to products ooataiaiBg 
copper associated with gold and silver For ores containing oo 
oxide or carbonate, the solvents employed are sulphuric actd, 
chloric acid, and ferrous chloride 

The original Hunt-Douglas process I involves treatment of tfee we 
at 70 C with a solution of ferrous chloride produced by the interaction 
of sodium chloride and ferrous sulphate The ferrous ehlonde converts 
copper oxide and carbonate into a solution of cuprous and cupnc 
chlorides, ferric hydroxide being precipitated and carbon dioxide 
evolved After filtration to remove ferric hydroxide the copper is 
precipitated by addition of scrap iron, the ferrous chloride thus regener- 
ated being available for further use in the first stage of the process 
The amount of iron required is small, but the method is handicapped by 
difficulty in filtering the ferric hydroxide, by the tendency of the copper 
solution to undergo atmospheric oxidation, and by the fact that any 
silver present is dissolved 

In the modern Hunt-Douglas process the ore is leached with dilute 
sulphuric acid, and the copper converted into cupric ehlonde by addition 
of ferrous chloride or calcium chloride The use of the calcium salt 
entails removal of the calcium sulphate by filtration The cupric salt is 
precipitated as cuprous chloride by reduction with sulphur dioxide, and 
the precipitate is converted into metallic copper by treatment with iron, 
or into cuprous oxide by the action of milk of lime In this process the 
amount of iron needed is proportionately small, feme hj dioxide is not 
precipitated, and silver is not dissoh ed 

When the ore contains cupious sulphide this salt is com erted into 
a soluble form cupric sulphate, soluble in \vater , cupric ovide, soluble 
m hydrochlouc 01 sulphuric acid , cupnc ehlonde soluble in A\ater , or 
cupious chloride, soluble in solutions of metallic chlondes 

Convcision into the sulphate is effected b\ \\eathermg, a slo\\ and 
expensive process , by calcination, foi oics containing a high percentage 
of iron pyrites , by calcination \\ith ieiious 01 aluminium sulphate , or 
by calcination with feme sulphate as an adjunct to the \\eathering 
process 

The transfoimation into oxide is caincd out b> calcination in a 
reverberatory furnace, or, if the sulphur is to be ieco\ered, in a muffle 

1 Hunt Oompt rend , 1869, 69 13o7 A Mtyei Bug und Hutten tuannische Zeit 
1862 21, 182 



258 NICKEL TIN 

any of the salts which it forms with acids all 
these will be found to give the same weight 
nearly , namely, 50 times the weight of an 
atom of hydrogen 

NICKEL The ore from which this metal is 
obtained, is found in Germany it usually 
contains several other metals, from which it is 
difficult to extract the nickel in a state of 
tolerable purity Nickel, when pure as it can 
be obtained, is of a silver white colour , its 
specific gravity is 8 279, and when forged 
8 666 It is malleable, both hot and cold, 
and may be beaten into a leaf of T 4-3- of an inch 
in thickness A very great heat is required to 
fuse it It is attracted by the magnet nearly 
as much as iron, and may be concerted into a 
magnet itself It combines with oxygen, sul- 
phur, and phosphorus , and may be alloyed 
with certain other metals 

The weight of its atom can scarcely yet be 
determined, for want of a more accurate know- 
ledge of the compounds into which it enters 
perhaps it will be found to weigh about 25, or 
else double that number, 50 

TIN This metal hab been long known, 
though it is found but in few place* compara- 
tuely Cornwall is the only part of Great 
Britain where this metal abounds , and its tin 
mines are the most celebrated in Europe 1 in 




COFFEE, 



The process patented by Jumaa 1 involves the sssfeaefcioa of the 
roasted ore with an ammomacal solution of axnmonium sulphate or 
sulphite Sulphurous acid reads with the solution thus formed, 
precipitating either cuprous sulphite or cupro-cupne sulphite 



The precipitated sulphite is redissotved IB aa aBaiwsiae&I solution of 
ammonium -sulphate or sulphit^ and the solution deetorfyz^dL 

Electrolytic Refining. 2 In 1865 Elfctngton patented a fsroeess $&r tfcfe 
electrolytic refining of copper, similar in principle to the method em- 
ployed at the present day In the modern process tfee bath is a solution 
containnig 12 to 20 per cent of copper sulphate and 4 to 10 per ee&t. of 
sulphuric acid A fairly pure anode of copper containing small amounts 
of silver, gold, arsenic, antimony^ iron, and other imparities is employed, 
the metal being deposited on a copper cathode A pure and cohmaat 
deposit of copper is obtained with a low current-density of 0*0048 to 
0484 ampere per sq cm , the noble metals being deposited in the aaode 
mud, and the other impurities remaining partly in this mud, and partly 
entering into solution If the current-density be too low, the deposited 
copper is pale and brittle , if too high, it is dark-brown and spongy 
Constant attention must be paid to the composition and degree of 
acidity of the electrolyte, both important factors influencing the nature 
of the deposit With rotating cathodes a good deposit is obtained with 
currents of high density, but in practice this modification is precluded 
by the disturbance of the anode mud, the solid particles in the electrolyte 
causing the formation of nodular growths on the deposited copper The 
yield of copper obtained by the electrolytic method usually corresponds 
with a current efficiency of 94 to 96 per cent , although it is possible 
to attain an efficiency of 98 per cent The bath is usually maintained 
at a temperature of 40 to 50 C 

Jumau's process (ut supra] for the electrolytic extraction of copper 
from its ores is also applicable to the production of pure copper from 
solutions of its compounds 3 The cupnc sulphite or cupro cupnc 
sulphite precipitated from the copper solution by the action of sulphurous 
acid or a sulphide is decomposed by sulphuric acid into cupnc sulphate 
and metallic copper The metal thus liberated is pressed into a form 
suitable for an anode, and refined electrolytically 

Refining by other Methods \anous other methods are a\ailable 
foi the purification of copper An example is the ready i eduction of 
cupious chloride by soft iron, a substance \uthout action on cupnc 
chloride Aluminium slowly reduces a warm solution of cupnc sulphate 
Vigoroux 4 lecommcnds a method depending on the action of aluminium 
on a solution of copper m concentrated hydrochloric acid 

1 German Patents 1907 Nos 189643 and 1J 1566 

Compaie Ulke Elel trolytische Raffination des Kupfers Halle 1904 burthtrb 
Elektwmetallurgie 3rd ed Leipsic 1903,185 Haber Zeitsch Elektrochem , 1903 9, 3b4 , 
Addicks, Ttans Amer Mectrochem Soc ,1904 5 120 Footer and Seidel ZeiUJi anorg 
Chem, 1897, 14 106 lorster and Coffetti Ber , 190o 38 2934 Ullmann Zeitsch 
Ekktrochem , 1897 3,516, Sand, Zeitsch physilal Chem 1901 35 041 bch\vab and 
Baum J Physical Chem , 1903, 7 o!4 Tians Amer Electrochem Soc 1903 4 55 \on 
Hubl, Mitiheil miUtar geograph List , 1886 6 51 Swan, J Soc Chem Ind 1U01, 20 663 
Kiham Berg und Hutten manmsche Zeit , 1885, 44, 249 McJohnson Trans Amer Electro 
chem Soc , 1901, 2, 171 

3 German Patent 1907 No 189974 1908, No 204673 

4 \igoroux, Bull Soc chim , 1907, [4], I, 7 



260 ZINC POTASIUM 

phosphorus, and forms alloys with most other 
metals 

The ultimate particle of lead, as deduced 
from a comparison of its oxides, sulphuret, and 
the salts in which it is found, I estimate at 95 
times that of hydrogen 

ZINC The ores of this metal are not rare , 
but the metal has not been extracted from them 
in a pure state, at least in Britain, much more 
than half a century Zinc is a brilliant white 
metal, inclining to blue. Its specific gravity 
is from 6 9 to 7 2 It was till lately considered 
as a brittle metal , but Messrs Hobson and 
Sylvester, of Sheffield, have discovered that 
between the temperature of 210 and 300% 
zinc yields to the hammer, may be laminated, 
wire drawn, &c and that after being thus 
wrought, it continues soft and flexible It 
melts about 680, and above that temperature 
evaporates considerably Zinc soon loses its 
lustre in the air, and grows grey , but in wa- 
ter it becomes black, and hydrogen gas is 
emitted Zinc combines with owgcn , and 
either it or its oxides combine with sulphur 
and phosphorus It forms alloys with most ot 
the metals, some of which are very useful 

The atom of zinc weighs nearly 56 times as 
much as hydrogen 
POTASIUM We are principally indebted to 



COPPER. 251 



copper is almost as great as tbat of 8dve*,* tfee Eafcio at 13 C bemg 
100 96 4 It has bean suggested that copper ca# chssolve to a minute 
extent m water 2 

The possibility of the existence of a metastable form of copper has 
been discussed by Cohen aad laroye * 

The molecular weight of the vajxmr has not beea detera09e^ fe& IB 
solution in mercury, 4 molten te, s and molten lead* tfee iso^ecidte 9 
monatomic 

Ocduswn of Gases 

Sohd copper occludes hydrogen (p 2B), but not Bitrogm, cacfeon 
monoxide, or sulphur dioxide 7 Merton 8 found that precipitated copper 
readily absorbs gases, which are expelled at high temperature After a 
few weeks its power of absorption vanishes 

Molten copper absorbs hydrogen & and sulphur dioxide, 18 the occluded 
gases being eliminated on coohug The liquid metal does not absorb 
nitrogen It combines with oxygen to form cuprous oxide, so that fall 
of temperature is not attended by evolution of the gas It decomposes 
hydrocarbons such as methane and ethane, with occlusion of hydrogen 
and separation of carbon 

According to Stahl, 11 the absorption of gases by molten copper gener- 
ally becomes greater with the temperature up to a certain point, with 
increase in the purity of the metal, and with the partial pressure of the 
gas At 650 C 100 grams of copper dissolve 1 milligram of hydrogen, 
and at 1500 C 14 milligram, the solubility of the gas in both solid and 
liquid copper increasing as the square root of the pressure The absorbed 
hydrogen has no influence on the conductivity of the metal 
1420 C 61 grams of copper absorb 15 c c of carbon monoxide, ^^ 
physical properties of the metal undergoing a marked change 

At 800 C and higher temperatures the ductility of copper is con- 
siderably increased by the presence of oxygen, but abo\e 720 C 
hydrogen has a weakening effect 12 

Electrolysis of a neutral or slightly alkaline solution of cupnc acetate 
with a copper anode and a platinum cathode yields a deposit regarded by 
Schutzenberger 13 as an allotropic form of copper It is a very brittle, 
bronze-coloured substance of low specific gra\ it\ and high electric re 
sistance It readily undergoes atmospheric oxidation, and decomposes 
nitric acid with evolution of nitrous oxide Schutzcnbcrgci s ongmil 
product contained cuprous oxide, and \\iedeniann 14 attnbuted its 
propel ties to the presence of this substance It is possible, hcn\e\ei, 

1 Compare Niccolai Atti R Accad Lmcei 1907 [o] 16 i UOb 
Tiaubc Manganm and Scala ibid 1909 [5] 18 i 342 

3 Cohen and Inouye Chem If ecLblad 1909 6 8bl 

4 G Meyer Zeifoch physilal Chem 1891 7 477 
Hcycock and Newlle Trans Chem *Soc 1890 57 37b 

b Heycock and Neville, ibid 1892 61 888 

7 Sievertb Zeihch Eleltrochem 1910 16 707 Su\citb and kiumbhaai ZciUch 
physikal Chem 1910 74,277 fetubbs Trans Chem &oc 1913 103 144o 

8 Merton Tran& Chem Soc , 1914 105 645 
bieverts Zeittch physikal Chem 1907 60 129 

Sieverts Zeitsch Elektrochem 1910 16 707 bicverU and Krumbhddi loc at 
Stahl MetallundErz 1914 II 470 
Bengough and Hanson J In&t Metals 1914 12 56 
Schutzenberger Compt rend 1878 86 1265 

Wiedemann, Pogg Annalen 1879 [2] 6 81 , compare bchutzenbergei Bull Soc 
chim, 1879, [2] 31 291 



262 

left to future experience Potasium, at the 
temperature of 32% is solid and brittle , and 
its fragments exhibit a crystallized texture at 
50% it is soft and malleable , at 60% it is im- 
perfectly fluid , at 100% it is perfectly fluid, 
and small globules unite as m mercury It 
may be distilled by a heat approaching to red- 
ness Its specific gravity is only 6 , this cir* 
cumstance would seem to countenance the 
notion of it& containing hydrogen Potasium 
combines with oxygen, sulphur, and phos- 
phorus , and it seems to form alloys with many 
of tfhe metals 

The weight of an atom of potasium appears 
from its combination with oxygen to be 35 
times that of hydrogen 

SODIUM Mr Davy obtained this metal 
from the fixed mineral alkali, or soda, by 
means of galvanism, in the same way as pota- 
$ium Sodium, at the common temperature, 
is a solid, white metal, having the appearance 
of silver , it is exceedingly malleable, and 
muqh softer than other metallic substances 
Its specific gravity is rather less than water, 
being 9348 It begins to melt at 120% and 
is perfectly fluid at 180 It combines with 
oxygen, sulphur, and phosphorus , and forms 
alloys with the metals 
The weight of an atom of sodium, as de- 



COPPER. 253 

oxygen is absorbed slightly more rapicBy than tfe$ moist gas. At 
ordinary pressure and temperature chlorine combines with the metal 
to form cupnc chloride and a small proportion of the cuprous salt , at a 
high temperature cuprous chloride is the sole product. Wfeea copper 
is heated in gaseous hydrogen chloride, capons chloride is pixxfocecl, 
and hydrogen evolved 1 At 1206* C the metal madfe slowly mfch 
carbon dioxide, forming cuprous oxide and carbon mm<md&P A& 
arc between copper poles burns m carbon dioxide almost as wdH a$ in 
air, but very imperfectly in coal-gas or steam 8 

Copper is not attacked by water at ordinary temperature^ or afc 
100 C , and only shghtly at white heat , but very prolonged immen&on 
m sea- water produces a superficial coating of cuprous oxide * It is 
insoluble in dilute sulphuric acid of 5 to 10 per cent strength, 5 but 
reacts with the concentrated acid in accordance with the equations * 



(1) 
this reaction probably taking place in the two stages 

(a) <^+H^O 4 =CuSO 4 +2E; 

(b) H 2 SO 4 +2H=SO 2 +2H 2 O , 
and 

(2) 5Cu+4H 2 SO 4 =Cu 2 S+3CuSO 4 +4H 2 O 

The first reaction proceeds between and 270 C , the second accom- 
panying it between and 100 C When the copper is exhausted, 
the cuprous sulphide is then decomposed in accordance with the 
equations 

Cu 2 S+2H 2 SO 4 =CuS+CuSO 4 +SO 2 +2H 2 O, 
CuS+2H 2 SO 4 =CuSO 4 +SO 2 +S+2H 2 O 

The black residue formed in the reaction appears to be mainly cuprous 
sulphide 

Nitric acid dissolves copper, forming cupnc nitrate and oxides of 
nitrogen The primary process corresponds with the equation 

Cu+2HN0 3 =Cu(NO 3 ) 2 +2H, 

but hydrogen is not evolved, being oxidized to watei by the nitric acid 
The action is conditioned by the presence of nitrous acid as a catalyst, 
since in absence of this acid the velocity of solution of coppci m nitric 
acid of moderate concentration is verv small A similai letaidition is 
produced by addition of substances capable of icactmg Avith nitious acid 
such as perchlorates, peimanganates, hydrogen peroxide or im i Ihe 
velocity of the reaction 

HNO 3 +2H =HNO 2 +H 2 O 

1 Wohler Annalen 1858 105 360 

2 von Bacho Monatsh 1916 37 119 

3 Hagenbach Physical Zeitsch 1909, 10 649 

4 Jonssen Chem Weelblad 1909 6 150 

5 Gannon Proc Roy Soc 1893 55 66 Schuster ibid 84 

6 Lunge Chem Industne 1886 9,47 Pickering Trans CJmn Soc 1S7S 33 112 
Baskerville J Amer Chem Soc 1895 17 904 1896 18 942 \in D^ enter Chem 
Weekblad 1905 2 137 1906, 3 515 Sluiter ibid 1906 3 63 

7 Millon Ann Chim Phys 1842 [3] 6 95 , J praJt Chem 1843 29 338 Vele^ 
Chem News 1889 59 303 1891 63 3, Proc Roy Soc 1890 48 458 Ihle Zeitsch 
physikal Chem , 1895, 19 577 



264 ARSENIC COBALT 

determinate from its compounds with oxygen 
and sulphur, and seems to be 40 times the 
weight of hydrogen 

ARSENIC Certain compounds of Arsenic 
were knoun to the ancients It seems to 
have been known in a distinct character for 
more than a century Arsenic has a blueish 
grey colour, and considerable brilliancy, which 
It soon loses by exposure to the air , its specific 
gravity is stated to be 8 S , its fusing point has 
not been ascertained, by reason of its great 
volatility it has been heated to 350% at which 
temperature it sublimes quickh , and exhibits 
a strong smell resembling that of game, which 
is characteristic of this metal It combines 
tvrth oxygen, forming one of the most virulent 
poisons , also with hydrogen, sulphur, and 
phosphorus , and it forms alloys with most of 
the metals 

The weight of an atom of arsenic, appears 
from its compounds to be 4-2 times that of 
hydrogen 

COBALT The ore of this metal has been 
long used to tinge glass blue , but it wns not 
till the last century that a peculnr mUil wao 
extracted from it Cobalt is of a gicy colour, 
inclining to red , it has not much lustre ih, 
specific gravity , s about 7 8 , it i* brittle , H 
melts at 180 of Wedgwood , it is attracted 



TABLE OF PRODUCTS FORMH> BY ACTION <W EXCESS 
OF A SOLUTION OF NITRIC ACID ON COPPER. 



Tenapeacatsire, 



Density of 
Acii 


HOt<gV 


NiO,{ine.) 
(HNO*) 


N0{<M5.). 


y&1fl* 


65 


105 




645 


585 


aei 


65 


110 





16*02 


548 


386 


60 


110 




284 


5226 


408 


25 


115 




8415 


5157 


185 


20 


120 




6049 


459 




20 


125 




7416 


890 




20 


' 180 


767 


1414 






17 


185 


1779 


10408 









140 


8405 


400 






15 


140 


8299 


428 






50 


140 


8279 


447 







Copper and its salts do not exhibit radioactivity, and have no action 
on the photographic plate x 

The suggested possibility of transmuting copper into lithium and 
sodium has already been mentioned (pp 55 and 87) 

Valency and Ions Copper is usually considered to exhibit umvalency 
in the cuprous compounds and bivalency in the cupnc compounds 
Its umvalency in the cuprous compounds accords with the position of 
the metal in the periodic system, and is exemplified by the resemblance 
of the cuprous halides to the hahdes of silver and univalent gold, and also 
by the isomorphism of cuprous sulphide and silver sulphide The 
bivalency of the atom in the cupnc compounds is m agreement with the 
properties of many of its derivatives, a typical example being the 
isomorphism of cupnc sulphate with the sulphates of ferrous iron, zinc, 
magnesium, and manganese 

Besides these two main classes of copper compounds, there appear 
to be other types of copper derivatives, among them oxides of the 
formulae Cu 4 O, Cu 3 O, Cu 2 O 3 , and Cu0 2 The cuptous ion, Cu , corre- 
sponds with the cuprous compounds, which are colourless in aqueous 
solution The cupnc ion, Cu , corresponds \\ith the cupnc com- 
pounds, which have a blue, green, violet, yello\\, or bro^n colour in 
solution 

The cupnc ion displays a characteristic po\\er of forming complex 
derivatives with ammonia 2 and substituted ammonias, an example 
being the cupnc ammonium hydroxides mentioned on p 254 A great 
number of other complex derivatives are demed from cupious or 
cupric ions In certain of these compounds both kinds of copper ions 
are present simultaneously, examples being the complex cupric cuprous 

1 Perman, Trans Chem Soc , 1908 93 1775 

2 Compare Hantzsch and Robertson Ber 1908 41 4328 1909 42 2135 Dawson, 
Ber 1909 42 720 Trans Chem Soc 1909 95 370 Bilt7 Zett^clt phyvlal Chem 
1909 67, 561 Poma, Atti R Accad Lincez, 1910, [5], 19 i 223 



266 CHROMIUM URANIUM MOLYBDENUM 

determined from its oxides, seems to be about 
40 times that of hydrogen 

CHROMIUM I his metal, united to oxygen 
so as to constitute an acid, is found in the ?ed 
lead 01 e of Siberia The pure metal being 
obtained, is white inclining to yellow , it is 
brittle, and requires a great heat to fuse it It 
combines with oxygen The other properties 
of this metal are not yet known Its atom, 
perhaps, weighs about J2 times that of hy- 
drogen 

URANIUM This metal was discovered by 
Klaproth, in 1789, in a mineral found in Sax- 
ony It is obtained with some difficulty, and 
only in small quantities , it has, therefore, 
been examined but by few The colour of 
uranium is iron grey , it has considc rable 
lustre, it yields to the file , its specific gravity 
is 8 1, according to Klaproth , 9 0, according 
to Bucholz Uranium unites with oxygen, and 
probably with sulphur its alloys have not been 
ascertained 

The weight of an atom of this metal, is pro- 
bably about 60 times that of hydrogen 

MOLYBDENUM The ore from which this 
metal is obtained is a sulphuret, called molyb- 
dena , but it requires an extraordinary heat to 
reduce it , the metal has not hitherto been 
obtained, except in small grains It is of a 



COPPER. 257 

Applications, Coppers employed in, large quantities m the manu- 
facture of electric conductors and appaa?a&% m& ibfc many othar 
purposes Its alloys are of the highest importance la liie arts* ex- 
amples being the so-called bronzing l^owiers, 1 brass, gim-xeetal, oosns, 
and so on 

*fhe effect of copper salts on tie growth of wheat lias b^jiin vestagated 
by Voeleker 2 for the sulphate and aarfoouafce Quantities between 
01 and 02 per cent* were found to have a stimulating effect. In 
smaller proportion the salts were without influence, aad m larger amount 
they exerted a toxic action 

Atomic Weight The accepted value for the atomic weight of 
copper, 63 57, is m good accord with the periodic system, the properties 
of the metal and its compounds being functions of an atomic weight of 
this or<ier b< lonjnnjj to an element of the fifth horizontal row of Group I 
of this system The atomic heat of copper at ordinary temperatures 
is 5 9 to 6 0, shghtly less than the mean value 6 4 for the solid elements, 
but sufficiently m harmony with the law of Dulo&g and Petit The 
isomorphism of the element with silver and gold, and that of the ctipi?ous 
compounds with the derivatives of umvalent silver, furnish additional 
evidence in favour of the atomic weight adopted 

Cryoscopic determinations of the molecular weight of copper in 
solution in other molten metals indicate the monatomic nature of its 
molecule 

Both chemical and physico-chemical methods have been employed 
in determining the atomic weight of copper A summary is appended 
of the values obtained by both types of process, expressed in terms of 
the modern notation O=16 The antecedent data employed in the 
recalculation from the experimental results are 

Ag=107880 C=12003 Na=22 996 

Ba=13737 H= 100762 8=32065 

Br = 79916 

A Chemical Methods In 1814 Wollaston 3 calculated the equiva- 
lent of copper to be four times that of oxygen, or Cu=64 

The early researches of Berzelms, 4 Erdmann and Marchand, 5 
Dumas, 6 and Millon and Commaille, 7 involved either syntheses or 
analyses of cupnc oxide, the values found for the atomic \\eight of 
copper being 63 30, 63 46, 63 5, and 63 13 Dumas also made syntheses 
of cuprous sulphide, but gave no details concerning his experiments 
His result did not differ much from the modern \alue, and -\\as adopted 
for many years 

Hampe 8 made t\vo series of experiments in 1874 In the first, 
copper was converted into the basic nitrate, and ignited in a cunent of 

1 Compare Groschuff Deut Mech Zeit 1912 14o 153 

2 Voelcker J Roy Agnc Voc Lngl , 1913 74, 411 

3 Wollaston Phil Tians 1814 104 21 

4 Beizelms Afhandlmgar i Fysik Ketm etc Stockholm, 1806-1818, 3 191 61 
Gilberts Annalen, 1811 37 284 Schueiggei s J 1820 30 3b4 Poyy Inmihn 182G 
8 182 

5 Erdmann and Marchand J pralt Chem 1844 31 380 

6 Dumas Ann Chim Pliy* 1859 [3] 55 129 

7 Millon and Commaille Compt rend 1863 57 145 

8 Hampe Zeitsch Berg Hutten nml Sahnen uesen 1874 21 218 Zeitscti anal 
Chem 1874 13 354 

VOL II 17 



268 COLUM2IUM fANTALIUM CERIUM 

nitre The atom of titanium probably weighs 
about 40 or 50 times that of hydrogen 

COLUMBIUM In 1802, Mr Hatchett dis- 
covered a new metallic acid in an ore con- 
taining iron, from America lie did not 
succeed in recHun.^ the acid to a metal , but, 
from the phenomena it exhibited, there was 
little room to doubt of its containing a peculiar 
metal, which he called columbium 

TANTALIUM This metal has lately been 
discovered by M Ekeberg, a Swedish che- 
mist A \ihite powder is extracted from 
certain minerals which appears to be an oxide 
of this metal When this white oxide is 
strongly heated along with charcoal, in a cru- 
cible, a metallic button ib formed, of external 
lustre, but black and void ot lustre within The 
acids again convert it into the state ot a white 
oxide, which does not alter its colour when 
heated to redness 

CERIUM The oxide of this metal is ob- 
tained from a Swedish mineral No one hii 
yet succeeded completely in reducing this ox- 
ide , so that the properties ot the metal, and 
even its existence, arc yet unknown But the 
earth or supposed oxide, is found to ha\e pro- 
perties similar to those of other oxides I hcse, 
of course, belong to a future article, the me- 
tallic oxides 



necessary corrections applied Both the water of crystallization and 
the copper m the pentahydxate of pure copper sulphate were determined 
In some of the experiments, after electrolytic depo&cfaon <rf the copper, 
the sulphuric acid produced in the electrolyses was titrated "with pore 
sodium carbonate, and the sodium sulphate formed was fused 
weighed The results were 

HaO CuJioO 25451, whence 



Cu Na^COg =100 1668SS, 
u NaO =100 



In one experiment the sulphate was precipitated with banum chloride, 
and the banum sulphate weighed , but the result is of little value, 

Richards also earned out three syntheses of cupnc sulphate from the 
oxide, and two from the metal, deriving the ratios 

CuS0 4 CuO=100 49838, whence Cu^GS 548* 
CuS0 4 Cu =100 097805, =63463* 

Five analyses of cupnc oxide by reduction m hydrogen furnished the 
ratio 

Cu O=79 900 20 100, whence Cu=63 602 

In 1906 Murmann 1 examined the composition of cupnc oxide, but 
his results are of doubtful value Copper oxide formed by heating the 
metal in oxygen was reduced by hydrogen, and values for the atomic 
weight varying between 63 513 and 64 397 were obtained Brauner 2 
regards the reduction-method as conducive of high values, but from the 
results of three oxidations he has calculated that Cu=6B 53 

In 1913 de Comnck and Ducelliez 3 converted metallic copper 
into the nitrate, and ignited the salt to oxide, their value being 
Cu=6355 

B Physico chemical Method This method consists in determining 
the electrochemical equivalent of copper \\ith respect to that of silver 
It involves passing the same quantity of electricity through solutions of 
cupric sulphate and silver nitrate, and weighing the metal deposited on 
the cathodes The early researches of (1) Ra}leigh and Mis Siclg\\ick, 4 
(2) Gray, 5 (3) Shaw, 6 and (4) Vanm 7 ga\e the results 

1 Cu 2Ag=100 340561, whence Cu = 63 354 

2 Cu 2Ag=100 340 935, , =03 2s5 
Q /Cu 2\g = 100 339953, ,,=-63408 
6 \Cu 2\g = 100 339983, ,-634(32 
4 Cu 24g=100 340406, ,-G33s3 

During an elaborate im cstigation of the clectiochcmicil equivalent 

1 Murmann Monatsh 1906 27 351 

Brauner Abegg and 4uetbachs HandbucJi dei anonjani (hoi Chenur Leip^ic 1908 
2 i 4b2 

3 Do Comnck and Ducelliez Rei gen Clum 1913 16 111 

4 Kayleigh and Mrs Sidgwick Phil Tran* 1884 175 470 
6 Gray Phil Mag 1880 [5] 22 389 IbSb [o] 25 179 

6 Shaw ibid 1886 [ r >] 23 138 

7 Vanm Wied Annalen 1891 [2] 44 214 



270 OXYGEN WITH HYDROGEN 

pounds, or at least to those which consist of 
three atoms, though they may be binary in the 
sense we use the term , and so on to the more 
complex forms 

This chapter will comprehend all the aeri- 
form bodies that have not been considered in 
the last, several of the acids, the alkalies, the 
earths, and the metallic oxides, sulphurets > 
carburets, and phospburets 

la treating of these articles, I intend to 
adopt the most common names for them , but 
it will be obvious, that if the doctrine herein 
contained be established, a renovation of the 
chemical nomenclature will in some cases be 
expedient 

SECTION 1 



OXYGEN WITH HYDROGEN 

1 Watii 

This liquid, the most useful and abundant 
of any in nature, is now well known both by 
analytic and synthetic methods, to be a com- 
pound of the two elements, oxygen and hy- 
drogen 

Canton has proved that water is in degree 
compressible. The expansive effect of heat 



Atomic Weights The results obtained by Gallo, a$d fey de Coauack 
and Ducelliez, accord reasonably with tins aumber; aad tliose of 
Shnmptoa are in good agreement* 

Calculating the foregoiag revolts on the basis Ag =107 883, Brainier * 
has arrived at the value On =63 56 from ratios considered by *** most 
trustworthy 

CUPROUS COMPOUNDS 2 

Cuprous hydride, CuBL Adctem of a concentrated solution of 
cupnc sulphate to a solution of hypophosphorous ae*d s or of ssapae 
hypophosphite 4 yields a powder containing 1 22 per cent of hydiogea, 
but the chemical individuality of the product is open to question. 
Berthelot 5 doubted the possibility of the existence of cupjpous hydnde, 
but more recent work has proved his views to be erroneous * The pure 
hydride can be prepared by the action of sodium hypophosphite on a 
moderately dilute solution of cupne sidphate at 70 C , but the product 
formed at ordinary temperature is contaminated with cuprous oxide 
and cupnc phosphate 7 It is a very unstable, reddish-brown substance, 
takes fire in chlorine, and is converted by hydrogen chloride mto 
hydrogen, copper, and cuprous chloride The dry substance cannot 
be kept for more than twenty-four hours, and at 60 C decomposes 
suddenly, leaving a sponge of metallic copper 

A very unstable copper hydride of unknown composition has been 
prepared in the form of a dark-brown powder by Stock and Kuss 8 by 
the interaction of cupnc sulphate and potassium hypoborate, KH 3 OB 
It decomposes readily, evolving hydrogen, and leaving a brown residue 
of metallic copper 

Cuprous fluoride, CuF The fluoride has been prepared by the 
interaction of hydrogen fluoride and cuprous chloride, and also by the 
dissociation of cupnc fluoride, both processes taking place at a high 
temperature 9 The product of the action of hydrogen fluoride solution 
on cuprous oxide 10 appears to be impure copper only n The fluoride 
is a ruby-red solid 

Cuprous chloride, CuCl The pure chloride is more readily prepared 
than any other cuprous compound A summary ol the more important 
methods is appended 

1 JBraunei, Abeyy and Aueibachs Handbuch der atwrgamsclien Chemie, Leipbic, 190b 
2,1 467 

2 Alloys of copper -with siher are mentioned on pp 297 and 301, and with gold on 
pp 333 and 336 Additional alloys aie descubed in the othei volumes of this series An 
mteiestmg example of cementation by ferro manganese it, given by biiowch and Gartoceti 
(Gaz~etta, 1921 51 u 24o) On heating a copper bai at 900 C with powdeied feno 
manganese and 5 per cent of wood chaicoal for some hours, a considerable proportion of 
manganese was found to have penetrated the copper 

3 \\uitz Cornet tend 1844 18 102 1879 89 lUOO IbbO 90 22 -inn Chun 
Pity 6 1844, [3J II, 2oO 

4 Schutzenbergei Compt tend 1869 69 190 

5 Berthelot Compt rend 1879 89 lOUo 

6 Myhus and Fiomm, Bu 1894 27 647 Lartktt \nd Merrill 4mer them J 
1912 17 185 Sie\ erts and Loessnei Zeit*ch anonj Lliun 1M1J 76 1 

7 Jnith and Myeib Trans Chetn Soc 1911 99 1329 Zeit*c/t anonj Lhtm , 1913 
8o,93 

8 Stock and Kuss Bet , 1914 47, 810 

9 Poulenc, Compt rend 1893, 116 1440 

10 Berzekus, Pogg Annalen, 1824, I, 28 

11 Mauro, Zeitsch anorg Chem , 1892, 2, 25 , Poulenc, loc cit 



272 OXYGEN WITH HYDROGEN 

place of the incumbent air, and its oressure is 
found inadequate to restrain the dilatation of 
the air in the water, which of course makes its 
escape But it is difficult to expel all the air 
by either of those operation*? Air expelled 
from common spring water, after losing 5 or 10 
percent of carbonic acid, consists of 38 per 
cent of oxygen and 62 ot azote 

Water is dht'iijubhcd for entering into 
combination with other bodies To some it 
unites in a small definite proportion, consti- 
tuting a solid compound This is the case m 
its combination with the fixed alkalies, lime, 
and with a great number of salts , the com- 
pounds are either dry powders or crystals 
Such compounds have received the name of 
hydiates But when the water is in excess, a 
different sort of combination seems to take 
place, which is called solution In this case, 
the compourd is liquid and transparent , as 
when common salt or sugar are dissolved in 
water When any body is thus dissolved in 
water, it ma} be uniformly diffused through 
any larger quantity of that liquid, and seems to 
continue so, without manifesting any tendency 
to subside, as far as is known 

In 1781, the composition and decomposition 
of water were ascertained , the former by 
Watt and Cavendish, and the latter by Lavoi- 



and CaraeHey * gives 4&4 C Camdley m& Williams * giro the boiling- 
point as 954 to 1052 C For the specific feat Regnanit s found the 
vafete 1SS8 

On exposure to light and moistere, cuprous chloride develops & 
violet or dark blue tot It &bo exhibits phototropy when iHuaersed 
m water slightly acidified with sulphurous add and subjected tx> the 
action of direct sunlight, the colour changing through greyish btae aosd 
dark blue to a dark-copper colour, with development of a nn^rfhe 
lustre after a few mimites Jot the dark the original white eofaor fe 
restored m about 48 hours IB absence of moisture the cblonde is 
not sensitive to light, the phenomenon being possibly due to the light 
inducing the formation of a hydrate unstable m the dark 4 In contact 
with damp air cuprous chloride is converted into a dark-green mixture 
of cuprac ehtande and basic cupnc chloride Watear transforms it into 
a mixture of copper, cuprous oxide, and cupnc chloride^ 

Assuming the valency of copper to be unity, the formula for cuprous 
chloride becomes 

tt-O 

Without postulating the umvalency of copper, the constitution of the 
salt can be represented by a double formula 

Cu-Cl 

i-Cl 

Determinations by Victor Meyer and his collaborators 6 of the density of 
gaseous cuprous chloride at 1600 to 1700 C gave values approxi- 
mately 6 5 times that of the atmosphere Taking air as unity, the 
vapour density calculated from the formula Cu 2 Cl 2 is 6 83 The close 
agreement between the two values supports the adoption of the double 
formula to represent the molecular constitution of gaseous cuprous 
chloride 

Cryoscopic determinations in dilute solution with pyridme, 7 qumo- 
line, 8 and tused bismuth chloride 9 as sol\ ents have pro^ ed the con- 
stitution of the salt under these conditions to correspond with the 
simpler foimul* Cu Cl Solutions in mercuric chloride consist of a 
mixture of single and double molecules 10 

The conflict of e\idcnce as to tin molecular formula of cuprous 
chloride precludes dogmatic gcneiahzation legaidmg the \alenc\ of 
copper in the cupious compounds As i mattei of expedient), it 
seems desirable to assume the um\ ilcncj ot the metal in these dema 
tives, a view supported bv other aiguments prc\iousl\ eited (p 255) 
To explain the foimation of double molecules an mteiesting assumption 

1 Cainellcy Ttan* Che tit koc lS7b 33 273 
Cdinelle> ind \\illi \m*> ibid IbhU 37 123 
< n Chun Phy* li>41 [J] I 12\) 

4 * Chem 8oc , 1922 121 782 

Li-scoem 'inn Chtm Phy* lb c >4 [7] 2 137 Hn^nod / P/n/ tcttl (. him lfc>97, 
I 411 hodlandti and Morbick Zcitsth anoitj them 1*M)2 31 1 4-^s 

b JiilU md \ittoi Mi >u Lu 1869 22 72j \ictoi Mt\ti ind tul AIc\ti Bir , 
1S79 12 G09 1112 llhd 1292 

7 WCIIKI Zeitt>ch anoig Chan 1S97 15 otoo 

8 Rib in Bull *!oc chim 1879 [2] 31 383 

9 biokmann and (jribil Zeitsch anorcj Chem 1900, 5 J -^(J 

10 Beckmann ibid 1907 55, 175 



274 OXYGEN WITH HYDROGEN 

of Volta's eudiometer, an instrument of the 
greatest importance in researches concerning 
elastic fluids It consists of a strong gra- 
duated glass tube, into which a wire is her- 
metically sealed, or strongly cemented , ano- 
ther detached wire is pushed up the tube, 
nearly to meet the former, so that an electric 
spark or shock can be sent from one wire to 
the other through any portion of gas, or mix- 
ture of gases, confined by water or mercury 
The end of the tube being immersed in a 
liquid, when an explosion takes place, no 
communication with the external air can arise , 
so that the change produced is capable of being 
ascertained 

The component parts of water being clearly 
established, it becomes of importance to de- 
termine with as much precision as possible, 
the relative weights of the two elements con- 
stituting that liquid The mean results of 
analysis and synthesis, have given 85 parts of 
oxygen and 15 of hydrogen, which are gene- 
rally adopted In this estimate, I think, the 
quantity of hydrogen is overrated 1 here is 
an excellent memon in the 53d vol of the 
Annal de Chemie, 1805, by Humboltd and 
Gay-Lussac, on the proportion of oxygen and 
hydrogen in water They make it appear, 
that the quantity of aqueous vapour which 



ooirga 

Other compounds of cuprous chloride mchide 




analogous to the ammonia compound cited in the 
aad its hy<JiocUonde, Cua^CeHg 

y3sN 6 , and CoCMHCL 7 
Cuprous bromide, CuBr Severaifmetbods aa?e available for the 

preparation of cuprous bromide, examples beang the interaction of 
copper-turnings and an aqueous solution of cupnc bromide at its 
Ixding-point, 8 and the difeefc synthesis feom biomiae aad excess of 
copper * The most convenient process is that of Saadmeyer * A sote* 
tion of capnc sulphate {12 5 grams), potassium bronoide {U6 grams), #Hjd 
concentrated sulphuric acid (6 c c ) in water (80 e,c ) is boiled under 
reflux with copper-turnings until the solution has become colourless 
After precipitation by fitoation through asbestos n*to a large excess of 
water covered with a layer of ether, the cuprous bix>mide is allowed to 
settle The mother-liquor is then syphoned off, and the salt is washed 
on a filter with water, alcohol, and ether, and dned IB a vacuum- 
desiccator over sulphuric acid 

The pure bromide is a white substance, but gradually develops a 
yellow tint, and on exposure to sunlight it acquires a bluish colour 8 
In phototropic character it resembles cuprous chloride, exposure to 
light changing its colour through dark green to dark copper If the 
duration of the action of the light has been limited to a few minutes, 
keeping in the dark for 30 hours reverses the colour changes n The 
melting-point of the bromide is given by Monkemeyer 12 as 480 C , 
and by Carnelley and Williams 13 as 504 C The boilmg-pomt 13 is 
between 861 and 954 C , and the density is given by Bodeker 14 as 4 72 

Cuprous bromide is insoluble in water Its solutions m hydro- 
chloric acid, hydrobromic acid, and ammonium hydroxide readily 
absorb carbon monoxide The maximum absorption for the ammom- 
acal solution corresponds with one molecule of carbon monoxide to each 
atom of copper 15 When prepared in absence of air, the solution in 
ammonium hydroxide is colourless, but on contact with oxygen it 
develops a blue colour The liquid obtained by dissol\mg cuprous 
bromide m an aqueous solution of sodium chloride or of sodium thio 
sulphate does not absorb carbon monoxide 

The heat of formation of the simple moleculai compound CuBr from 
solid coppei and liquid biomme is 24 985 Cal 16 

1 Koireng Jahtb Mm Bed Bd , 1914 37 51 compare bandonnim C a Mia 1914 
41 i 290 

2 Korreng loc cit 3 Huntingdon Chnn ^>eu , Ibs2 46 177 

4 Raschig, Bet , 1884 17 679 Heumann ibid , 1874 7 1390 

5 Saglier Compt tend 1888 106 1422 

6 Lang Bei 1892 21 1584 

7 Neumann MonattJi 1894 15 492 

8 Renault Compt rend 1864, 59 329 

Berthemot Ann Chun Pnys 1830 [2] 44 224 3So Colbon Compt nn<1 189U 
128 1458 Rammelsbcrg Pogg Annalen 1842 55 246 

10 Sandinejer Ber 1884 17 2650 compaie Dungtb Cowpt icnd 18&9 1 08 ob7 

11 Singh Trans Chem Soc , 1922 121, 782 

1 Monkemeyer JaJirb Mm Bed Bd 1909, 22 1 

13 Carnelley and Williams, Trans Chem Soc 1880 37 125 

14 Bodeker DieBeziehungenzwischen Dichte und ZusammenscLung bet f eaten und liquid*. n 
Stiffen, Leipsic, 1860 

15 Manchot and Friend Annalen, 1908 359 100 

16 Thomsen Thermochemistry (Longmans, 1908) 270 



27b OXYGEN WITH HYDROGEN 

of oxygen unites witti one of hydrogen to form 
one of water Hence, the relative weights of 
the atoms of oxygen and hydrogen are 7 to 1 

The above conclusion is strongly corrobo- 
rated by other considerations Whatever may 
be the proportions m which oxygen and hy- 
drogen are mixed, whether 20 measures of 
oxygen to 2 of hydrogen, or CO of hydrogen 
to 2 of oxygen, still when an electric spark is 
passed, water is formed by the union of 2 mea- 
sures of hydrogen with 1 of oxygen, and the 
surplus gas is unchanged Again, when wa- 
ter is decomposed by electricity, or by other 
Agents, no other elements than oxygen and hy- 
drogen are obtained Besides, all the other 
compounds into which those two elements 
enter, will in the sequel be found to support 
the same conclusion 

After all, it must be allowed to be possible 
that water may be a ternar) compound In 
this case, if two atoms ot hydrogen unite to 
one of oxygen, then an atom of oxygen must 
weigh 14 times as much as one of hydrogen , 
if two atoms of oxygen unite to one of hydro- 
gen, then an atom of oxygen must weigh 3 3- 
times one of hydrogen 



COPPER. 



Several complex derivatives of cuprous iodide itave been pi 
including CuI^NH* 1 , 2CuI > 2NH 4 I > ll 2 O s , 




Copper soixxbde, Cu/> The ohve-greesa preciprfcafce pa?c 
the interaction of solutions of potassium stanmte aad eiiprue j 
appears not to be the subouade or quadxantoxide, Cu 4 O, but a : 
01 cuprous oxide and copper 6 

Cuprous oxide, Cu a O This oxide occurs as tibe i0meral cupr&e or 
rtd>y copper It is formed l>j aredndaoa of alkaline solutions of complex 
cupnc salts with a reducing sugar, such as dextrose, an example being tke 
reduction of Fehling's solution, 6 the oxide being deposited as a ie$* 
crystalline powder 

Cuprous oxide is produced in the form of an orange-yellow, amor- 
phous gel containing water by tike reduction of an alkaline cupnc 
solution with sodium hyposulphite 7 



A better method is the action of hydroxylamHie on. a cupnc salt in 
presence of alkali 8 The initial hght-yellow product is probably a 
hydroxide In absence of air, the colour quickly ch<uiges to orange or 
brick-red, the phenomenon being probably due to elimination of water 
The dry product contains 2 to 3 per cent of water, but above low red 
heat this water is expelled, the metastable, yellow, amorphous oxide 
becoming transformed into the stable, red, crystalline variety 

Other methods of formation are the addition of sodium carbonate 
to a solution of cupnc sulphate and sodium chloride reduced with 
sulphurous acid, 9 and that of an alkaline solution of sodium potassium 
tartrate to a solution of cuprous chloride and sodium chloride 10 At 
temperatures below 350 C copper reacts with nitrous oxide to form 
cuprous oxide , above this temperature the product is cupnc oxide u 
Cuprous oxide is also formed at the anode in the electrolysis of a solution 
of cupnc sulphate, 12 and by heating cupnc oxide in steam 

The oxide crystallizes in cubic octahedra, melting above 1230 C 
according to Truthe, 13 and at 1235 C under a pressure of 6 mm 
according to Robeits and Hastings Smyth, 14 and of density 5 75 to 6 09 15 
Its solubility in water is \ ery slight, but it dissoh es readily in aqueous 
solutions of ammonia, less readily m potassium hydroxide, 16 and easily 
m hydiogen hahdes, with formation of complex dematncs The 

1 Ramiuelsberg Poyy -innalut Ib39 48 102 
Saghei Compt tuid Ibb7 104 1440 3 Biun ibid Ib92 114 007 

4 Rofc,e Poyy 4nnak)i 1803 [4] 30 1 

Mosci Zcitbch anonj Chem 1909 64 200 compare Recoura Com}>t iLnd 1909 
148 1105 

Mitbcherlich / pi alt Chtm 1840 19 4oO Buttgci -innakn Ib41, 39 176 
J ptakt Chan Ib03 90 103 

7 Mo%er loc cit 

b Moser, Zeit*ch anorg Chem 1919 105 112 compare Paal ind Dexhcimer Ber , 
1914 47 219o SUIIIA Chem \eu* 1921, 122 99 

9 Rubbtll Che in \iut> 1894 68 308 

Giogtr Zcittth anoiq Chem 1902 31 320 
Sibaticr and bintleienjs Conipt ttttf] Ib9o, 120, 018 
\k>ti Bull Sor (.lant kd<i 1 ( >08 22 2o9 

liutlu ZcitH/i (tnottj ( hem 1912 76 101 

1 Kobuts and Habtmgb Srnjth J 4.tne> Chun Soc 1M21 43 K0l 

1 Coiupaie Cliikc Constant* of I* at ute 2nd ed \\ ishm^tun 188S i, 34 33 
lb Guntz and Bassett Bull Soc chim , 1906 [3] 35 201 



278 OXYGEN WITH HYDROGEN 

Some of the properties of this acid are, 1 In 
the elastic state it is destructive of combustion, 
and of animal life , it has a pungent smell, 
somewhat like muriatic acid, and not less suf- 
focating , its specific gravity has not been ac- 
curately obtained , but from some experiments 
I have made, it seems to be extremely heavy 
when obtained in glass vessels , in fact, it is in 
that case a superfluate of silica Into a clean 
dry flask, I sent a quantity of fluoric acid gas , 
after some time, the mixture of common air 
and acid was corked, and the flask weighed 
it had acquired 12 grains The flask was next 
inverted in water, to see how much would be 
absorbed, and that quantity was taken for the 
acid gas The capacity of the flask was 26 
cubic inches, containing originally 8 2 grains 
of common air, 12 cubic inches of acid gas 
had entered According to this, if the whole 
flask had been filled with the gas, it would 
have gained 26 grams , consequently, 26 cubic 
inches of the acid gas would weigh 342 
grains, and its specific gravity be 4 17 times 
that of common air This experiment was 
repeated with a proportional result The flask 
became partially lined with a thin, dry film 
offluate ot silica during the operation, which 
no doubt contributed so iuh n^ to the weight , 
but I am convinced, from other experiments 



COPPER 267 

Several complex derivatives of cuprous iodide have been prepared, 
including CuI,2NH s l , 2CuI,2NH 4 I,H 2 2 , CuI,NH 4 I,4(NH 4 ) 2 S 2 O s 8 , 
2CuI,(NH 4 ) 2 S 2 3 ,H 2 3 , 2CuI,K 2 S 2 3 ,H 2 0*, and 20^^,8,0^,0 8 

Copper sutxmde, Cu 4 The olive-green precipitate produced by 
the interaction of solutions of potassium stanmte and cupnc sulphate * 
appears not to be the suboxide or quadrantoxide, Cu 4 O, but a mixture 
of cuprous oxide and copper 6 

Cuprous oxide, Cu 2 O This oxide occurs as the mineral cupnte or 
ruby copper It is formed by reduction of alkaline solutions of complex 
cupnc salts with a reducing SUIT ir, such as dextrose, an example being the 
reduction of Fehling's solution, 6 the oxide being deposited as a red, 
crystalline powder 

Cuprous oxide is produced in the form of an orange-yellow, amor- 
phous gel containing water by the reduction of an alkaline cupnc 
solution with sodium hyposulphite 7 

2CuO+Na 2 S 2 O 4 +2NaOH=Cu 2 O+2Na 2 SO s +H 2 O 

A better method is the action of hydroxylamme on a cuprie salt in 
presence of alkali 8 The initial light-yellow product is probably a 
hydroxide In absence of air, the colour quickly changes to orange or 
brick-red, the phenomenon being probably due to elimination of water 
The dry product contains 2 to 3 per cent of water, but above low red 
heat this water is expelled, the metastable, yellow, amorphous oxide 
becoming transformed into the stable, red, crystalline \ ariety 

Other methods of formation are the addition of sodium carbonate 
to a solution of cupnc sulphate and sodium chloride reduced with 
sulphurous acid, 9 and that of an alkaline solution of sodium potassium 
tartrate to a solution of cuprous chloride and sodium chloride 10 At 
temperatures below 350 C copper reacts 'with nitrous oxide to form 
cuprous oxide , above this temperature the product is cuprie oxide n 
Cuprous oxide is also formed at the anode in the electrol} sis of a solution 
of cuprie sulphate, 12 and by heating cuprie oxide m steam 

The oxide crystallizes in cubic octahedra, melting abo\e 1230 C 
accoidmg to Truthe, 13 and at 1235 C under a pressure of 6 mm 
accoidmg to Robeits and Hastings Sm} th, 14 and of density 5 75 to 6 09 15 
Its solubility in \vatei is 'very slight, but it dissolves ieadil\ in aqueous 
solutions of ammonia, less readil} m potassium hydroxide, 16 and easily 
in hjdiogen hahdes, \\ith foimation of complex dematrves The 

1 Pamindbberg Poyg 4.nnahn t 1839 48 Ib2 
bi e hti Compt nml 1887 104 1440 3 Biun ibid 1892 114 bb7 

4 Ro&e, Pogij innalui I8b3 [4] 30 1 

Mosoi ZiifaJt anonj them lyou 64 200 compaie Kecoma Cotnjt ttnd 1909 
148 llUo 

Mitbchcilicn J ittdlt Chun 1840 19 4jO Butt er Initahn Ib41 39 17b, 
J pi alt them, 1603 90 16o 

7 Mobcr loc cit 

* Moser Zeifach anorg Chem 1019 105 112 compare Paal iiid Dc\hcimei Ber 
1914 47 219o ^uini Chem \cw 1921 122 99 

9 Kub-stll C/icm \td Ib94 68 308 

Gio^cr Zitttch anonj Chem 1*102 31 32b 

1 Sibititi iml Sciult iciib toHipt u nil Ib95 120 bib 
\lt\ci Bull ^m i him bdtj 1908 22 2^9 

J liutht ZciUtJi (inoHj Chem 1912 76 Ibl 

4 Robiitb iml Halting*. Smjth J imu Chim Soc 1 ( )21 43 Kibl 

1 CompaitCluK Conttantb of \atute 2nd ed \\ dtehm^tun 1888 I, o4 oo 

10 Guntz and Basbttt Bull Soc chim , 1906 [3] 35 201 



280 OXYGEN WITH HYDROGEN 

which common air always contains in a dif- 
fused state 5 Fluoric acid combines \\ith 
the alkalies, earths, and metallic oxide&, form- 
ing salts denommated/z^zto 

The weight of an atom of fluoric acid may 
be investigated from the salts jnto which it 
enters as an integral element Of these, the 
jiuate of hpie is most abundant, and best 
known Scheele is said to have found 57 parts of 
lime, and 43 of acid and water, in fluate of lime 
Richter finds 65 lime, and 35 acid in this salt 
These are the only authorities I know they 
differ materially In order to satisfy myself, 1 
took 50 grains of finely pulverised spar, and 
having mixed with it as much, or more, strong 
^ulphunc acid, the whole was exposed to a 
heat gradually increasing to redness , the re- 
sult was, a hard dry crust of mixed sulphate 
and fluate of lime , this was pulverized, then 
weighed, and again mixed with sulphuric 
acid, and heated as before , this piocess was 
repeated two or three times, or as long as an} 
increase of weight was found At last, a dry 
white powder, of 75 grains, was obtained, 
which uas pure sulphate of lime Ihis expe- 
riment, two or three times repeated, gave al- 
ways 75 grains finallv Hence, >0 grains of 
fluate of lime contain ju^t as much lime as 75 
grains of sulphate of lime But sulphate of 



COPPER 269 

acid and sulphuric acid with decomposition * The heat of formation 
evolved m the direct combination of the elements is 19 Cal 2 

When suspended in a solution containing both ammonia and 
ammonium (or other) salts, air at atmospheric pressure oxidizes cuprous 
sulphide to cupnc sulphate and thiosulphate, the reaction being slower 
than with cupnc sulphide In suspension in neutral or acidic solutions, 
cupnc sulphate is produced, the reaction being less energetic than in 
presence of ammonia, and up to 160 C requiring compressed air 3 

With sodium monosulphide cuprous sulphide forms a double salt of 
the formula Na 2 S,Cu 2 S 4 This compound melts at 700 C 

Cuprous sulphite, Cu 2 SO 3 Sulphur dioxide reacts with a solution 
of cupric acetate in acetic acid to form colourless, hexagonal leaflets, 
Cu 2 SO 3 ,H 2 O 5 In aqueous solution sulphur dioxide converts this 
substance into a red, prismatic form, CugSOgjE^O, also formed by the 
action of this gas on alkali cuprous sulphites in presence of water 6 The 
sulphite is capable of forming complex ammonium derivatives of the 
type Cu 2 S0 3 ,(NH 4 ) 2 S0 3 5 

Cuprous sulphate, Cu 2 SO 4 Cuprous sulphate cannot be isolated by 
methods analogous to those employed for the preparation of the cuprous 
halides Metallic copper dissolves in solutions of cupric sulphate con- 
taming free sulphuric acid, an equilibrium >r i-pop<li IL with the 
scheme 

2Cu:^Cu +Cu 

being attained At ordinary temperatures the proportion of cuprous 
sulphate formed is small, but it is increased by rise of temperature 7 

Cuprous sulphate was first isolated by Recoura 8 by the interaction 
of molecular proportions of cuprous oxide and methvl or ethv 1 sulphate 
at 160 C in absence of moisture The presence of excess of the alkyl 
sulphate induces decomposition of the product with formation of cupric 
sulphate 

Cu 2 0+(CH 3 ) 2 S0 4 =Cu 2 S0 4 +(CH 3 ) 2 

The salt is dned by washing with ether and placing m a \acuum- 
desiccator over sulphunc acid 

The sulphate is a light grey powdei, mstanth decomposed 03 -\\ater 
in accordance with the equation 9 

[Cu 2 SOJ+Aq =CuSO 4 (dissohed)+[Cu|+21 Cal 

Since the heat of solution of anhydrous cupnc sulphate in \\ iter is 15 8 
Cal , the transformation of a gram molecule of cupious sulphate into 
cupnc sulphate and copper is attended b's the solution of 5 2 Cal , 
the icaction being exothermic The foimation oi cupious sulphite is an 
endothcrmic reaction, although that of each of the othei cupious silts 
is accompanied bv evolution of heat \t oidman tuiipciatuies in 
presence of dry air, cuprous sulphate is stable, but contact \uth moist 
air induces a very slo\v decomposition The picscncc oi cthei icndeis 

1 Compare Waihmont Mdalhugie 1909 6 b3 

2 Wartenberg Zeit*ch physical Che/n 1900 67 440 

3 Gluud Bar , 1922, 55 [B] 952 

4 Fnednch Metall undJStz 1914 II 79 

Ram berg Zeitsch pltysikal Chew 1909 69 j!2 
6 Rogojsky Annalen 1851 80 255 iStird Commit and Iss2 95 3b 

Foer^tei and Blankenberg Bet 1906 39 4428 
s Recoura Compt rend 1909 148 1105 
9 Compare Cundall Trans Chem Soc 1914 1 05 60 



282 OXYGEN WITH HYDROGEN 

that this vapour is the same in quantity for at- 
mospheric air, oxygen, hydrogen, azote, and 
carbonic acid, and probably for most other 
gases This vapour can be abstracted from the 
gases by any body possessing an attraction for 
water , such as sulphuric acid, lime, &c In 
short, it can be taken out, as far as is known, 
by any body that w ill take out pure steam 
Some authors consider the vapour united to 
the air by a slight affinit} , others call it hy- 
grometrical affinity, &c My opinion on this 
subject has already been stated, that the steam 
mixed with air differs m no respect from pure 
steam , and, consequently, is subject to the 
same laws There are some elastic fluids, 
however, which have so strong an affinity for 
water, that the) will not permit this steam 
quietly to associate with them , these are fluo- 
ric, muriatic, sulphuric, and nitric acids No 
sooner are these acid gases presented to anv 
air containing steam, but they seize upon the 
steam , the two united, are converted into a 
liquid, visible fumes appear, which after play- 
mg about a while, are observed to fall down, 
or adhere to the sides of the vessel, till the gas 
no longer finding any steam present, occupies 
the volume of the vessel in a transparent state, 
free from everv atom of vapour 1 hesc acid 
gases cannot exist one moment along with 



COPPER 271 

Cuprous carbide or acetylide, Cu 2 C 2 The acetylide is formed by 
the action of acetylene on an ammomacal solution of cuprous chloride, 1 
or on a suspension of cuprous oxide in water 2 It is a brownish-red, 
amorphous substance, and explosive in the dry state 3 Prepared by the 
first method, it is associated with a molecule of water, 4 which can be 
removed by drying over sulphuric acid The presence of this water has 
been attributed to adsorption, 5 and another explanation assumes the 
compound to have the formula CH==CCu,CuOH 6 Cuprous acetylide 
forms complex derivatives with solutions of cuprous chloride and 
potassium chloride in hydrochloric acid 7 Among the examples of those 
described are the colourless 2CuCl,C 2 H 2 and 4CuCl,KCl,C 2 H 2 , the yellow 
8CuCl,2KCl,C 2 H 2 , and the violet 2CuCl,Cu 2 O,C 2 H 2 Manchot 8 found 
that excess of acetylene combines with cuprous chloride to form white 
crystals of the formula CuCl,C 2 H 2 In presence of hydrochloric acid 
a dark violet powder of the composition CuCl,C 2 Cu 2 ,H 2 O is precipi- 
tated In the dry state this substance is moderately stable Acetylene 
combines with excess of cuprous chloride to form white prisms of the 
composition 2CuCl,C 2 H 2 

Cuprous carbonate Carles 9 claims to have prepared cuprous 
carbonate as a glaucous green powder, insoluble in water, by the action 
of copper on copper carbonate in presence of liquefied ammonia 

Cuprous cyanide, CuCN Addition of potassium cyanide to a solution 
of cuprous chloride in hydrochloric acid precipitates cuprous cyanide 10 
The best method for its preparation is to mix cold aqueous solutions 
of potassium cyanide (65 grams) and cupnc sulphate (130 grams), and 
expel cyanogen by warming the mixture under an efficient air-extrac 
After settling, the cuprous cyanide is decanted, and washed with wau 
alcohol, and ether u References to other methods of preparation, ana 
to Sandmeyer's process for aromatic nitnles, are appended 12 

Cuprous cyanide is a white solid, and is soluble with difficulty in 
water It is dissolved readily by cold, concentrated hydrochloric acid, 
and is reprecipitated from this solvent by addition of an aqueous 
solution of potassium hydroxide In contact with air, its colourless 
solution in ammonium hydroxide develops a blue tint The salt is also 
dissolved by aqueous solutions of ammonium chlonde, sulphate, and 
nitrate, and by warm, dilute sulphuric acid None of its solutions has 
the power of absorbing cirbon monoxide 13 The heat of formation of 

1 Berthclot Ann Glum Phys 1866 [4] 9 385 

2 Kciscr Avner Chcm J 1802 14 285 

3 Borthtlot loc cit With hydiochlonc acid cupious acetylide yields impure 
acetvlcno probxbly contaminated with diicet}kne HC==C C=CH (Noycs and Tucl or 
Attier Chcm J 1807 19, 123) 

4 Hlochminn 4.nnaltn 1874 173 174 

1 icbcrminn and Damcrow Her 1892 25 109b 

8 Schcibci Ber 1008 41 3810 compxio Mai o\vl a ibid 824 

7 Chxvastelon Compt rend, 1898 126 1810 127 68 1900 130, 1034, 1764 
131 48 1901 132 1489 

s Manchot Annahn 1912 387 257 

9 (aiks Butt fior chim 1015 |4] 17 163 

10 Proust J de Physique 1804 59, 350 Meucsallyemcines Journal da Chemie (Gchlen) 
1806, 6 573 

11 J deque mm Ball Soc chim 1885 [2] 43 550 Vaict Cornet rend 1890, 
no 147 

1 Vauquolm Ann Chim Phys 1818 9 120 Wohki Annalcn 1851 78 370 
Rammelsberg Pogg Annalen 1837 42 124 Sandmcyor Bei , 1884, 17, 2050 
13 Manchot and Friend, Annalen, 1908 359, 100 



284 OX\GEN WITH HYDROGEN 

particular, IQj grains of potasium were burned 
in 19 cubic inches of fluoric acid, 14 of which 
disappeared, fluate of potash was formed, and 
2^. cubic inches of hydrogen were evolved 
Here it is evident, that both oxygen and hy- 
drogen were found in the fluoric acid, and 
must have made an integral part of that acid, 
as no vapour could subsist m it , whence it 
appears, that both oxygen and hydrogen are 
essential to fluoric acid Moreover, it is highly 
probable that the pure acid m the 14 inches of 
gas, weighed about 6 grains, (common air be- 
ing 4-) and the oxygen necessary for 10~ po- 
tasuim, would be 2 grains , whence the acid 
entering into composition, would be about 
twice the weight of the oxygen united to the 
potasium 

I shall now relate some of my own expe 
nments on the decomposition or this acid 

1 Fluoric acid gas may, 1 find, be kept in 
glass tubes for several hours or days, without 
any change of bulk , it continues at the end 
absorbable by water as at first Two suc- 
cessive trials were made, by electrifying about 
30 water gram measures of the gas After 
two hours electrification, no change of volume 
was produced Water was then admitted, 
\vhich absorbed all but 4 gram measures , to 
this 1 1 measures of hydrogen were added, and 



COPPER 273 

Cupnc fluoride, CuF 2 Evaporation 1 or precipitation with alcohol 2 
of a solution of cupnc oxide or carbonate in excess of hydrofluoric acid 
yields the fluoride in the form of dihydrate It crystallizes m small, 
blue needles, slightly soluble in cold water, and converted by heat into 
the anhydrous salt The interaction of gaseous hydrogen fluoride and 
cupnc oxide also produces the anhydrous form as a white solid It is 
soluble in mineral acids, is reduced by hydrogen, and is converted into 
cupnc oxide by heating m air Hot water transforms it into a pale 
green, shghtly soluble basic fluonde, Cu(OH) 2 ,CuF 2 , 1 a substance also 
produced by interaction of solutions of cupnc sulphate and potassium 
fluonde 2 An acid salt, CuF 2 ,5HF,5H 2 0, has also been described 3 

Cupric chloride, CuCl 2 The anhydrous chloride is produced by 
heating copper or cuprous chloride in chlorine, or by dehydrating the 
dihydrate by heating at 150 C in an atmosphere of hydrogen chloride, 4 
or by addition of concentrated sulphunc acid to its aqueous solution 5 
It is a brownish-yellow, hygroscopic solid, melting at 498 C , 6 of density 
3 054 7 It is readily soluble m water and organic solvents Its heat of 
formation from its elements, calculated from the interaction of cupric 
oxide and hydrochloric acid, is given as 51 63 Cal 8 and 51 4 Cal 9 It is 
decomposed by heat into the cuprous salt and chlorine 10 

The dihydrate, CuCl 2 ,2H 2 0, is prepared by evaporating a solution of 
cupric oxide or carbonate in hydrochloric acid , or by evaporating a 
solution of cupric sulphate and sodium chloride, the dihydrate crystal- 
lizing out after sodium sulphate and chloride , or by addition of barium 
chloride to a solution of cupric sulphate, filtering, and concentrating 
It crystallizes m green, deliquescent, rhombic prisms, but a blue, non- 
deliquescent form has also been described u The density of the dihydiate 
is 2 47 to 2 535 12 Its solubility at 17 C is 43 06 grams m 100 grams 
of water 13 A tnhydrate, CuCl 2 ,3H 2 0, exists at low temperatures 14 

Numerous basic cupric chlorides have been described, although some 
of them may not be true chemical compounds 15 As examples of these 
substances may be cited the green, rhombic crystals of the mineral 
atacamite, CuCl 2 ,3Cu(OH) 2 ,nH 2 0, <<nl i i _ a varying pioportion of 
water , the crystalline compound CuCl 2 ,3Cu(OH) 2 , formed from brown 
cupric hydroxide and cupric chlonde solution 16 , and the compound 
CuCl 2 ,3CuO,2H 2 0, 17 foimcd by the interaction of solutions of potassium 
hydroxide and cupric chloride 

Among the double salts of cupric chloride with other metallic salts 

1 Berzehus Omehn Kraut's Handbucli der anotg Chem 6th ed Heidelberg 1872-1897, 
3 648 

2 Balbiano Gazzetta, 1884, 14 74 

3 Bohm Zntsch anonj Chew 1905 43 326 

4 feabatier Bull Soc chim 1895 [3] 13 598 

5 Viaid Compt rend 1902 135 1C8 

Carnelley Trans Chew Soc 1878 33 273 

7 Playfairand Joule Mem Chem Soc 184 r > 2 401 1848 3 57 Favre and Valson 
Compt rend 1874 79 968 

8 Thomson Thct Biochemistry (Longmans 1908), 269 

9 Berthelot Thermochimie, Pans 1897, 2, 319 

10 Rose, Pogq Annalen 1836 38 121 u Stanford CJiem Neiv?, 1863 7 81 

12 Compare Clarke Constants of Nature 2nd ed , Washington 1888, i, 24 

13 Reicher and van De venter Zeitsch physilal Chem 1890 5 559 

14 Chuard Archives Geneve 1888, [3] 19,477 

15 Compare Dammer, Handbuch der anorg Chem , Stuttgart, 1892-1903, 2, n 668 
10 Sabatier Compt rend 1897 125 101 

17 Miller ind Kennck, Tians Roy Soc Canada, 1901-1902, [2] 8 m 35 

VOL II 18 



286 OXYGEN WITH HYDROGEN 

and oxygen, and nothing besides as far as is 
certainly known Now, as the weight of one 
atom of hydrogen, and two of oxygen, just 
make 15 times that of hydrogen, there is great 
reason to presume that this must be the con* 
stitution of that acid Besides, analogy is 
strongly in favour of the conclusion , an atom 
of the other elementary principles, azote, car- 
bone, sulphur, and phosphorus, joined to two 
atoms of oxygen, each forms a peculiar acid, 
as will be shewn in the sequel , why, then, 
should not one atom of hydrogen and two of 
oxygen, also form an acid ? 



3 Muriatic Acid 

To obtain muriatic acid in the elastic state, 
a portion of common salt, muriate of soda, is 
put into a gas bottle, and about an equal 
weight of concentrated sulphuric acid , by the 
application of a moderate heat to the mixture, 
a gas comes over, which may be exhibited over 
mercury , it is muriatic acid gas 

Some of the properties of muriatic acid gas, 
are 1 It is an invisible elastic fluid, having 
a pungent smell , it is unfit for respiration, or 
for the support ot combustion , when mixed 
with common air, it produces a white cloud, 



COPPER 275 

Cupric lodate, Cu(I0 3 ) 2 Solution of cupnc hydroxide or carbonate 
in a solution of lodic acid yields the lodate, which is known in the 
anhydrous form, 1 and as monohydrate, 2 and dihydrate 3 From excess 
of a solution of potassium lodate, cupnc nitrate precipitates the pale blue 
monohydrate At 25 C its solubility is 3 3 X 10~ 3 gram-molecules per 
litre of water 4 A basic lodate, Cu(I0 3 ) 2 ,Cu(OH) 2 , has also been 
prepared 5 

Cupric penodates A number of penodates has been obtained by 
dissolving cupnc hydroxide or carbonate m a solution of periodic acid, 
and also by the interaction of sodium penodate, NaI0 4 , and solutions of 
cupnc salts 6 They have the formulae 2CuO,I 2 O 7 , 6H 2 , 4CuO,I 2 O 7 ,H 2 , 
4CuO,I 2 O 7 ,TH 2 O , and 5CuO,I 2 7 ,5H 2 O 

Cupric oxide, CuO This oxide is obtained as a black, amorphous 
powder by igniting cupnc hydroxide, carbonate, or nitrate 7 It is also 
formed on copper anodes in electrolytic oxidation 8 The amorphous 
oxide can be converted into lustrous, cubic tetrahedra by heating with 
potassium hydroxide, 9 the crystalline variety being also produced^ by 
ignition to redness in a platinum crucible of a small amount of cuprous 
chloride 10 

A blue variety of cupnc oxide is said to have been prepared by pre- 
cipitating cupnc sulphate with sodium hydroxide in presence of dissolved 
aluminium u On heating strongly, it blackens, the change being 
probably due to an agglomeration of the particles On the other hand, 
Muller and Ernst 12 state that agitation of cupric oxide or hydroxide with 
sodium hydroxide produces a blue precipitate of sodium cuprite On 
warming the mixture, this substance dissolves, and on cooling separates 
in crystals In contact with excess of water, these crystals decompose 
to form the black oxide 

Cupric oxide occurs as the hexagonal tenonte, and also as the rhombic 
or monoclmic melacomte According to Slade and Farrow, 13 the oxide 
melts above 1148 C , with partial decomposition into cuprous oxide , 
but Smyth and Roberts 14 state that it does not melt with dissociation 
below 1233 C Its density is 6 32 to 6 43 15 Its mean specific heat is 
1420 between 12 and 98 C , 16 and its heat of formation 37 16 Cal 17 

1 Ditte Ann Chim Pliys , 1890 [6], 21 173 Granger and de Schulten Compt rend, 
1904 139 201 

2 Rammelsberg Pogg Annalen, 1838 44 569 

3 Millon Ann CMm Phys 1843 [3] 9 400 

4 Spencer Zeitsch physical CJiem 1913 83 290 

5 Granger and do Schulten Compt rend , 1904 139 201 

6 Bcngieser Annalen 1836 17 254 Langlois Ann CJum /%<? 1852 [3] 34 257 
Lautsch J pralct Chem 1867 100 85 R iminelsbc r^ Pogg Annaltn 186S 134 519 

7 Vogel and Reischauer Dingier 9 PolytccJi J 18 r ) c ) 153 197 Jalnc^b 1S63, 274 
Frdmann and Marchind J pralct Chem 1844 31 389 

8 Mallei and Spitzer, Zeitsch anorg Chem , 1906 50, 321 feclimiedt Zeitsch Elclho 
diem 1908 15 53 

9 Becquerel Ann Chim Phys 1832 51, 101 

10 Schulze, J prakt Chem 1880 [2] 21 413 

11 Schenck J Physical Chem 1919 23 283 

12 Muller and Ernst Zeitsch angew Chem 1921 34 371 

13 Slade and Farrow Zeitsch Elektrochem 1912 18 817 compare Wohler and Foss, 
ibid 1906 12 781 

14 Hastings Smyth and Roberts J Awer Chem Soc 1920 42 2582 

15 Schroder Pogg Ann Jubelband 1874, 452 compare Olaike Constant* of Nature 
2nd ed , Washington 1888 I 65 

lfi Regnault Ann Chim Phys 1841 [3] I 129 

17 Thomsen Thermochemistry (Longmans, 1908), 268 



1288 0\YGFN WITH HYDROGLN, 

and five hundred times Us bulk of the gas, at 
the common temperature and pressure , that 
is, rather less than an equal weight This 
combination of water and muriatic acid gas, 
constitutes the common liquid muriatic acid, 
or spirit of salt of commerce , but it is never 
of the strength indicated above It is usually 
of a yellow colour, owing to some atoms of iron 
which it holds in solution 

The constitution of this acid, is a question 

that has long engaged the attention of chemists 

Thisacidseemsmoredifficultlv decomposed than 

most others Electricity, so powerful an agent 

in the composition and decomposition of other 

acids, seems to fail in this In the Phil Tr for 

1800, Dr Henry has given us the results of a 

laborious investigation on this subject From 

these it appeals that pure, dry muriatic acid 

gas, is scarcelv affected by electricity A very 

small diminution in volume, and some traces 

of hydrogenous gas, w^re observed, which he 

ascribes to the water or steam which the gas 

contains But we have already icmarLed, 

(page 283) that muriatic acid gas naturally 

contains no steam , or, if it contains any, it 

must be much less than other gases contain 

It is probable, therefore, that the hydrogen 

was derived from the decomposition of part of 

the acid r l his conclusion is strengthened by 



COPPER 279 

(p 269), but more energetic * Its heat of formation from its elements 
is 11 6 Cal 2 It dissolves readily in hot, dilute nitric acid, and in 
solutions of sodium polysulphides 3 

Copper polysulphides An orange-red substance of the formula 
CuS 3 is obtained by fusing cupnc sulphate with sodium carbonate and 
sulphur Heating with carbon disulphide converts it into an amorphous, 
dark-brown substance, Cu 2 S 3 4 Another polysulphide, Cu 2 S 6 , is stated 
to be formed by the interaction at C of a solution of cupnc acetate and 
calcium polysulphide 5 It has a reddish-brown colour It is doubtful 
whether any of these polysulphides is a true chemical compound 

Cupnc sulphite The normal sulphite is unstable, and has not been 
isolated With solutions of cupric sulphate sodium sulphite gives a 
green precipitate of varying composition, but containing basic salts 6 

Cupnc sulphate, CuSO 4 The sulphate is prepared by the action of 
dilute sulphuric acid on cupric oxide or carbonate, the salt crystallizing 
as pentahydrate on evaporation It can also be obtained by dissolving 
the metal in nitric acid, and decomposing the nitrate by means of 
sulphuric acid With access of air, the metal is also converted into the 
sulphate by sulphuric acid 

Several methods are applicable to the production of cupric sulphate 
on the manufacturing scale Old copper plates are heated with excess of 
sulphur to bright redness in a reverberatory furnace with closed doors 
until combination is complete The doors are then opened, and the 
mass is oxidized at dull-red heat When oxidation is complete, the 
hot product is transferred into dilute sulphuric acid, and the clear 
solution concentrated after decantation The crystals formed are of a 
moderate degree of purity The process is also applicable to coarse 
copper, and to copper-glance and other sulphur ores of copper 

When the ores contain iron, it is impossible to sepaiate the 
feirous sulphate and cupric sulphate by crystallization If the mixed 
sulphides are roasted at a suitable tempeiature, the ferrous sulphate 
formed is converted into oxide Anothei method of sepaiation depends 
on heating a solution of the two sulphates under pressure at 180 C , the 
ferrous salt crystallizing out 7 For agricultural purposes the removal of 
the iron is unnecessary 

Crude copper 01 one of its oics can also be loasted in an, and tians 
formed into the sulphate by the action of sulphui dioxide 8 

Ihc coppei can iirst be convex ted into eupnc chlonde by the aetion 
of chlorine and water With sulphune aeid the salt ioimed leaets to 
pioduce cupric sulphite anel hydrochlouc acid 9 

The formation ol cupnc sulphate can also be eifected by dissolving 
the oxide m sulphune acid 10 If the oxide has been piodueed from an 

1 Oluul her 1922 55 |_BJ 952 

2 Waituibug Adktii phyttlal Chcm 1909 67 440 
J iio&sin^ Zeit&ch anal Chem 1902 41 1 

1 Rossmg /icit^ch anon/ Ghetn 1900 25 407 
Bodioux Compt tend 1900 130 H97 

Chcvrcul Ann Chun Phijs 1812 [1] 83 181 llammclsbu D Pogq 4nnalen 
184(> 67 397 Scubcrt and Mtcn deiUch anaiy Ckein 1S93 4 44, Millon and 
Commaille Compt rend , 1863 57 820 

7 Urn Stench Patent 1903 No 328800 

8 Gin Chem News 190* 88,554 Bntuh Patent 1903 No 5230 

9 Dancr F tench Patent 1904 No 350421 
10 Coste, ibid , 1908, No 392617 



290 OXYGEN WITH HYDROGEN 

form only 14 6 grains of muriate of potash, to 
which adding 2 gram for the 8 cubic inches 
of hydrogen, gives 14 8 instead of 19 grains 
I would therefore adopt the general fact, 
which was confirmed by several experiments, 
and is entirely consistent , namely, that when 
potasium in sufficient quantify is binned in mu- 
riatic acid gas, the whole of the gas disap- 
peais, and fiom one thud to one fourth of its 
volume of fnjdingen is ecolved, and muriate of 
potash Jot med 1 his is one of the most im- 
portant facts that has been ascertained, re- 
specting the constitution of muriatic acid 
Now, the elements of muriate of potash are 
as follow 35 grains of potasium +7 of oxy- 
gen = 42 of potash , and 12 potash + 22 mu- 
riatic acid = 6 I grains of muriate of potash 
From this it appears, that the oxygen in mu- 
riate of potash is nearly I of the u eight of the 
acid According to this, when potasium is 
burned in muriatic acid gas, nearly ' of the 
whole weight (for the hydrogen weighs little) 
goes to the oxidi/ement of the potasium, and 
the remaining J unite with the potash formed 
Hence, when 22 cubic inches, or 11 grains 
of ejas disappear, as in the particular experi- 
ment lately mentioned, 2J. grains nearly must 
have been oxygen derived from the acid, and 
8^ grains of acid joined to the potash so 



COPPER 281 

References to other researches on the solubility of cupnc sulphate are 
appended 1 

The investigations of Lescoeur 2 on the vapour-pressure of the 
hydrates confirm the assumption of the existence of the pentahydrate, 
trihydrate, and monohydrate MacLeod-Brown 3 has suggested two 
formulae for the pentahydrate to explain the step-by-step removal of 
water 

A detailed examination of the mechanism of the dehydration of the 
pentahydrate has been made by Guareschi 4 Over calcium chloride at 
21 to 28 C , or in air at 45 to 50 C , it loses two molecules of water, 
forming the pale sky-blue trihydrate In a thermostat at 60 C the 
trihydrate gives up two more molecules of water, but exposure to air 
at the ordinary temperature reconverts it into the pentahydrate The 
molecule of water present in the monohydrate is expelled at 206 C , 
and not at 114 C as stated by Pierre, the elimination of the second half 
taking place slowly Guareschi regards the monohydrate as having the 
formula 

/>v /OH a / OH H0 \ ,o. 

Cu< >S=0 , and the semihydrate as Cu< >SO - - S0< >Cu. 



\OH X X 

The heat of formation of the anhydrous salt from its elements is 
given as 181 7 Cal 5 and 182 6 Cal 6 

With excess of cupnc sulphate reduction with hypophosphorous 
acid yields metallic copper, but with excess of the acid cuprous hydride 
is precipitated 7 Cupnc sulphate is also reduced by hydroxylamme 8 

Copper forms a number of basic sulphates, among them the mineral 
langtfe, 9 CuS0 4 ,3CuO,4H 2 0, prepared artificially by Sabatier 10 by the 
interaction of cupric hydroxide and a solution of cupric sulphate The 
mineral brocha^te, 2CuS0 4 ,5Cu(OH) 2 , has been piepared in the 
laboratory from cupric sulphate solution by the action of limestone u 
Shenstone 12 has described a crystalline sulphate, CuS0 4 ,2Cu(OH) 2 
On mixing concentrated solutions of cupric sulphate and ammonium 
carbonate, and diluting the deep-purple solution, a voluminous, 
blue precipitate of the formula 15CuO,SO 3 is produced 13 Othei 
basic sulphates of this type are 3CuO,SO 3 , 4CuO,SO 3 , 5CuO,S0 3 , 

1 Poggiale, Ann Chim Phyd 1843, [3] 8 403 , lobler Anualen, 1855 95, 193 , 
Biandes and innhaber Gmdin Krauts Handbuch der anorg OTiem , 6th ed Heidelberg 
1872-1897,3 G31 , Patuck and Aubert Trans Kama** 4c<td &a 1874 19 Ltud 
Compt rend 1887 104 1C14 1892 114, 112, Ann Glum Pkys 1894 [7J 2 503 
Cohen Zeitsch Elektrochem 1903, 9 433 Cohen Chattawiy, and lombiock, Zettscft 
physikal Ghem , 1907 60 706 

2 Lescceur Compt rend 1886 102 14G6 , Ann Cfnm Pity* , IbOO [6] 21 511 
compare Frowein, Zeitsch physikal Chem , 1887 I 11, Andit it ibid 1691 7, 260 
Muller Eizbach, ibid , 1896, 19 135 

3 MacLeod Blown Chem News 1914 109 123 

4 Guareschi, Alii R Accad 8ci Torino 1915 50 1125 compile Pitue Ann Chim 
Phys 1846 [3] 16 241 250 Merwin J Washington Acad Set , 1914 4 494 

5 Berthelot TJiertnoc/unnc Paris 1897, 2, 323 

6 Thomson ThenuochetMsti y (Longmans, 1908) i24 

7 Sieveits and Majoi 2/citsch anorg Chun , 1909 64 29 

8 Adams and Overman J Amet Chem Soc , 1909 31 637 

9 Giaham Annalen 1839 29 29 10 Sabatiei Compl tuid,l$>$l 125 101 

11 Becquerel Compt rend , 1852 34 573 

12 Shenstone Trans Chem Soc 1885, 47, 375 

13 Pickering, ibid , 1909, 95, 1409 



292 OXYGEN WITH HYDROGEN 

in the same quantity of gas, and then trans- 
ferring the acid to mercury he observes, 
c there was no notable difference in the results ' 
The inference must, I conceive, be erroneous , 
100 cubic inches of muriatic acid gas, united 
to potash, must give more muriate of potash, 
than if potasium was burned in the same gas , 
the weights of the materials necessarily require 
it , unless it be found that the two muriates are 
not the same salt 

From all the muriates, or salts, into which 
the muriatic acid enters, it appears (as will be 
shewn when these salts are considered) that the 
weight of an atom of muriatic acid is 22 times 
that of hydrogen Very soon after this deter- 
mination, it occurred to me that hydiogen \\as 
probably the base of the acid , if so, an atom 
of the acid must consist of 1 atom of hydrogen 
and 3 atoms of oxygen, as the weights of these 
just make up 22 In 1807 this idea uai> an- 
nounced, and a suitable figurative represen- 
tation of the atom was given, in the Chemical 
Lectures at Edinburgh and Glasgow , but this 
constitution of the acid was hypothetical, till 
these experiments of Mr Ddvy seem to put it 
past doubt The application of the theor) to 
the experiments is as follows on the suppo- 
sition that the specific gravity of muriatic add 
gas is 1 67, it will be found that 12 mea&uies 



COPPER 283 

magnesium sulphate three types are produced at ordinary temperatures 
almost colourless, rhombic prisms with 7H 2 O , light blue, monochme 
crystals with 7H 2 O , dark blue, tnchmc crystals with 5H 2 l 

Complex salts of cupric sulphate with cupnc chloride, potassium 
sulphate, and potassium chloride have been described 2 

With ammonia, cupric sulphate combines to form complex de- 
rivatives Thermochemical data 3 indicate the existence of CuSO 4 ,NH 3 , 
CuSO 4 ,2NH 3 , CuSO 4 ,4NH 3 , and CuS0 4 ,5NH 3 The existence of 
the complex CuSO 4 ,4NH 3 has also been postulated from physical 
measurements 4 The compound CuS0 4 ,4NH 3 ,H 2 O can be prepared by 
passing ammonia into a solution of cupric sulphate It is stable in dry 
air 5 The compound CuSO 4 ,5NH 3 has been prepared by Rose 6 and 
by Mendeleeff 7 

In alcoholic solution cupric sulphate combines with nitric oxide to 
form a double compound of the formula CuS0 4 ,NO 8 

Cupric selemde, CuSe Hydrogen selenide precipitates cupric 
selemde from solutions of cupric salts, and it is also produced by the 
action of selenium vapour on copper 9 It is a greenish-black substance, 
of density 6 66 

Cupric selemte, CuSe0 3 At 360 C cupric oxide combines with 
selenium dioxide to form the selemte as green rods insoluble in water 10 

Double Copper Selenates Tutton 11 has investigated the crystallo- 
graphic properties of double selenates of the series R 2 Se0 4 ,CuSeO 4 ,6H 2 O, 
R representing potassium, rubidium, caesium, or ammonium They are 
isomorphous with the monochme double salts formed by cupric sulphate 
with the sulphates of potassium, rubidium, caesium, and ammonium 12 

Cupric tellunde, CuTe The telluride is stated to be formed by the 
action of tellurium-powder on a solution of cupric acetate in presence of 
sulphur dioxide 13 It can also be precipitated from a solution of sodium 
telluride, Na 2 Te , a sesqmtellunde, Cu 2 Te 3 , is obtained similarly from 
the polytelluride Na 4 Te 3 (p 130) 14 A telluride of the formula Cu 4 Te 3 
occurs as the mineral nckardite 

Cupric thiosulphates Complex cupnc alkali thiosulphates have been 
prepaicd by Dutoit 15 

Cupric dithionate, CuS 2 6 ,5H 2 The tnchmc pentahydratc is pre 

I llctgcib Zuttch phybikal Chew 18 J4 15, 571 Hollnmnn ibid 11)01 37 193 
fechi uiicnidktis and do Baat Ptoc K Alad \\etenbch Amsterdam, 1914, 17, ^33 

3 Bouzat, Compt rend 1902, 135,292 534 

4 Compare Keychler Butt Soc chim 1895 [3] 13 387 Bei 1895 28, 555 Kuuo 
\v ilnil J Rut>s Phyt> Ghent /Soc 1899 31,910, Immci\\ahr Zeitbdi anonj Client 1900 
24 209 Daw&on and McCrae Trans Chem Soc 1900 77 1239 1901 79 1072 Cans 
Zcil*Ji anoxj Cheat , 1900 25 236 Perrnan Ttan^ Chan boc 1902 81 487 Bouzit 
Cow jtt ? UK/, 1902 134,1216 Ann Chim 7%6 190 i [7] 29 305 J ockc und 1 orss ill 
Amcr Chew J 1904 31 208 Da\\son Tiant> Chew but 1900 89 1000 Hoin 
Amu Chan J 1907 38 475 

5 Horn and laylor Amet Chun J , 1904 32 253 compaic Hum, ibid 1907 38, 
475 Andui Compt und , 1885 100 1138 

Kobe J*oy</ Annakn 1830 20 150 

7 Mciiddccll tier 1870 3 422 

8 Minchot Ber 1914 47 1001 

J little Annalen 1859 112 211 
10 Uspil Compt und 1911 152 378 

II lutton Ptot Hoy hoc 1920 [A] 98 07 
1 Compile pp 227-230 

1J Pukinan Jahn&bcricht 1S61 120 Amct Chun J 1&02 [2] 33 328 
14 libbals J Awer Chem Soc 1909 31 902 
1 Dutoit, J Ofow phys , 1913, 1 1 050 



294 OXYGEN WITH HYDROGEN 

1 measure, and on letting up water the whole 
was absorbed, except one measure, which 
appeared to be hydrogen I sent 700 shocks 
through a mixture of muriatic acid gas and 
hydrogen , there was no change A mixture 
of muriatic acid gas and sulphuretted hydrogen 
being electrified, hydrogen was evolved, and 
sulphur deposited, but no change of volume 
It was evident the sulphuretted hydrogen only 
was decomposed When a mixture of oxvgen 
and hydrogen is fired along with muriatic acid 
gas, water is formed, and it instantly absorbs 
nearly Us weight of acid gas From these and 
such like unsuccessful attempts to decompose 
the muriatic acid, the importance of Mr Davy's 
experiments is manifest 

The relation of muriatic acid to water must 
now be considered It has been stated that 
water at the common temperature and pressure, 
absorbs 400 or more times its bulk of the acid 
gas , that is, rather less than its own weight 
Now, j atoms of water weigh 24, and 1 atom of 
the acid gas weighs 22, it seems probable, then, 
that the strongest liquid acid that can well be 
exhibited, is a compound of 1 atom of acid 
and 3 of water, or contains about '18 per cent 
acid It is seldom sold of more than half this 
strength Mr Kirwan's table of the strength 



COPPER 285 

formed by heating cupric chloride in phosphme * Other phosphides of 
the formulae Cu 5 P 2 , CuP 2 , 2 and CuP 5 3 have been described, but it is 
doubtful whether they are true chemical compounds 

Cupric hypophosphite, Cu(H 2 P0 2 ) 2 The solution obtained by 
addition of slightly less than the equivalent proportion of barium hypo- 
phosphite to a solution of cupric sulphate yields, after removal of the 
barium sulphate and addition of alcohol, the hypophosphite in the form 
of white crystals 4 At ordinary temperatures the dry salt does not 
decompose for several days, but at 90 C it explodes with evolution of 
phosphme On warming in aqueous solution, it decomposes with 
formation of phosphorous acid, copper, and hydrogen Its aqueous 
solution is also decomposed catalytically by palladium 

Cu(H 2 P0 2 ) 2 +2H 2 =2H 3 P0 3 +Cu+H 2 

Cupric phosphite, CuHP0 3 ,2H 2 O A phosphite of this formula is 
obtained by the interaction of solutions of diammomum hydrogen phos- 
phite and cupric chloride, or of phosphorous acid and cupric acetate 5 
It is unstable, but admits of drying at a medium temperature 

Cupric orthophosphate, Cu 8 (PO 4 ) 2 ,3H 2 The orthophosphate is 
prepared by the interaction of disodium hydrogen phosphate and 
excess of cupric sulphate, 6 or by heating an aqueous solution of ortho- 
phosphoric acid with cupric carbonate at 70 C 7 It is a blue, 
crystalline powder, almost insoluble in water 

The basic orthophosphate, Cu 3 (PO 4 ) 2 ,Cu(OH) 2 , occurs as hbethemte in 
the form of dark green crystals, produced artificially by heating the 
orthophosphate with water 7 In combination with two molecules o 
water it also occurs as tagihte 

Cupric pyrophosphate, Cu 2 P 2 7 The anhydrous salt is precipitated 
as a greenish-white powder by addition of sodium pyrophosphate to a 
solution of a cupric salt 8 The pentahydrate crystallizes fiom a solution 
containing cupric sulphate and sodium metaphosphate 9 

Cupric metaphosphate, Cu(PO 3 ) 2 The metaphosphate is foimed by 
evaporating to dryness an aqueous solution of cupric nitrate and ortho- 
phosphonc acid, and heating the residue at 316 C 10 The tett ahydrate 
is prepared by precipitating with alcohol a solution of cupric sulphate 
and sodium metaphosphate u 

Cupric arsenites A pigment of varying composition is prepared as a 
canary-green precipitate by mixing solutions of an alkali metal aisemte 
and cupric sulphate 12 It is known as Scheme's gieen Othei cupric 
derivatives of arsenious acid are also known 13 

1 Hose Pogg Annalen, 1826, 6 206 1832, 24 295 compare Bottger JahresbencJit 
1857, 107 

Rubenovitch, Compt rend 1898, 127, 270 1899, 129 330 Gianger ibid , 1895, 
120 023, 1896 122 1484 

3 Bossuet and Hackspill ibid , 1913 157, 720 

4 Fngel ibid, 1899 129 518 

5 Rose Pogg Annalen 1828 12, 291 Wurtz Ann Chim Phys , 1846 [3], 16, 199 
Rimmelsbcrg Pogg Annalen 1867 132 491 

' Stemschneider Dissertation Halle 1890 

7 Debriy Ann Chim Phys 1861 [3], 61, 439 

3 Persoz l fcM, 1847 [3] 20 315 Fleitmann and Henneberg Annalen 1848,65 387 

8 Wiesler Zeitsch anorg Ghem , 1901 28 201 

10 Maddrell Annalen 1847 61 60 " Fleitmann Pogg Annalen 1840 78 242 

1 Bloxam J Ghem Soc 1862 15 281 

" Reichard, Ber 1894 27,1019 Stavenhagen, J prakt Chem 1895 [2] 51,! 



296 OXYGEN WITH HYDROGEN. 

contain so many grains of pure acid , the third 
contains the grains of acid in 100 water gram 
measures 3 this is convenient in practice to 
prevent the trouble of weighing the acid , the 
fourth contains the specific gravity of the liquid 
acid , and the fifth contains the temperature 
at which acids of the various stiengths boil 
This last is entirely new, I apprehend , it 
shews a remarkable giadation of temperature 
the strong acid boils at a moderate heat , as 
the acid weakens, the boiling temperature 
rises till it gets to 232 , after which it gra- 
dually d*ops agam to 212 When an acid 
below 12 per cent is boiled, it loses part of 
its quantity, but the remainder, T find, is con* 
centrated, on the other hand, an acid stronger 
than 12 per cent is rendered more dilute by 
boiling It aopears from a paper of Dr R 
Percival in the 4th vol of the Irish Transac- 
tions, that in the ordinary process of manu- 
facturing the muriatic acid, the middle pro- 
duct is usually of the strength which boih at 
the maximum temperature , but the first and 
last products are much stronger The reasons 
for these facts will probably be found in the 
giadation of tempcratuie in the above column 



COPPER 287 

commercial copper carbonate to be similar in constitution to malachite, 
a view questioned by Dunmcliff and Lai 1 

Sodium hydrogen carbonate and cupnc sulphate react to precipitate 
a blue, basic carbonate, 5CuO,3C0 2 ,wH 2 5 converted by drying at 
100 C into another blue hydrate, 5CuO,3C0 2 ,7H 2 O Another basic 
carbonate is also produced in the same reaction It has the formula 
8CuO,3CO 2 ,6H 2 0, is dark blue in colour, and becomes green at 100 C 
No other basic carbonate was isolated by Pickering All the products 
are insoluble in water and sodium-carbonate solution, but dissolve 
slightly in solutions of carbon dioxide and of sodium hydrogen carbonate, 
with production of the normal carbonate or a double carbonate 

Feist 2 has prepared a basic carbonate, 7CuO,4CO 2 ,H 2 0, by powder- 
ing together crystallized cupnc sulphate and sodium carbonate, and 
then adding water It is difficult to separate the substance from a basic 
cupnc sulphate simultaneously formed Auger 3 has described an 
amorphous basic carbonate of the formula 8CuO,5C0 2 ,7H 2 Another 
basic carbonate, 7CuO,2C0 2 ,5H 2 O, has been prepared 4 by the inter- 
action of a mixture of sodium carbonate and sodium hydrogen carbonate 
with cupnc sulphate in aqueous solution Complex carbonates of copper 
with sodium and potassium have also been obtained 5 An example 
of this type of double salt of the formula Na 2 Cu(CO 3 ) 2 ,3H a O crystallizes 
on addition of a solution of cupnc acetate to one of sodium carbonate 
and sodium hydrogen carbonate at 50 C 6 It forms needles or rosette- 
like agglomerations, and above 100 C it is converted into cupric oxide 
and sodium carbonate with elimination of water and carbon dioxide 
It is decomposed by water, but can be recrystallized from a concentrated 
solution of sodium carbonate containing sodium hydrogen carbonate 

Cupnc cyanide, Cu(CN) 2 The cyanide is obtained as a brownish- 
yellow precipitate by the interaction of solutions of potassium cyanide 
and cupric sulphate, but it is very unstable, decomposing at ordinary 
temperatures into cupnc cuprous cyanide, Cu[Cu (CN) 2 ] 2 ,5H 2 O, with 
evolution of cyanogen On heating, it is converted into cuprous 
cyanide With hydrazme cyanide it unites to form a monohydrazmate, 
Cu(CN) 2 ,N 2 H 4J yellow needles insoluble in water, m p 160 to 162 C 7 

Cupric thiocyanate, Cu(CNS) 2 The thiocyanatc is formed as a 
velvet-black precipitate by adding basic cupric carbonate or cupric 
hydroxide to a solution of thiocyamc acid, and by the interaction of 
potassium thiocyanatc and concentrated solutions of cupric salts 8 It 
is very unstable, being transformed by contact with water into cuprous 
thiocyanate 9 With ammonium hydroxide it yields blue, acicular 
crystals of ammonio cupnc thiocyanate, Cu(CNS) 2 2NII 3 , also produced 
by dissolving cupric hydroxide in ammonium thiocyanatc 10 

Cupric silicates The emerald-green, hexagonal dioptase, CuSiO 3 ,H 2 O, 
has the density 3 28 to 3 35 The turquoise-blue chrysocolla has density 

1 Dunmchff and Lai Tranv Chem Soc 1918 113 718 

Feist Arch PJtarw 1000 247 439 
3 Augei Compt rend 1914 158 944 4 Dunmchff and I al loc cit 

Pickering Trans Chem Soc 1909 95 1409 1911 99 800 
e Applcbey and T ane ibid 1018 113 609 

7 Fian/enand lucking Zeitsch anorg Chem 1911 70 145 

8 Mcitzendorff Poqg Annalen 1842 56 63 SodoibaoJ (Annalen, 1010 419, 217) pre 
piiod it by the action of thiocyanogen (p 320) in ether solution on cuprous thiocyanate 

9 Clans J prakt Chem 1838 15 403 

10 Grossman, Zeitsch anorg Chem 1908 58 265 



298 OXYGEN WITH HYDROGEN 

temperature of 60 and common pressure of 
pure gas, water takes up about twice its bulk 
of the gas If the gas be diluted with air, 
then much less is absorbed, but the quantity 
is not proportionate to the abstract pressure of 
the gas, as is the case with those gases men- 
tioned at page 201 Thus, if the pressure of 
oxymunatic acid gas be th of atmospheric 
pressure, watei will be found to take up |ds 
of Us bulk, uhich is more than twice the quan- 
tity it ought to take by the rule of proportion 
Hence it is evident, that the absorption of this 
gas by water, is partly of a mechanical and 
partly of a chemical nature 

3 Watei impregnated with the gas is called 
liquid oxymunatic acid It has the same 
odour as the gas, and an astringent, not acid, 
taste When exposed to the light of the sun, 
the liquid acid is gradually decomposed, as 
was first observed bv Berthollet, into its ele- 
ments, muriatic acid and oxygenous gas , the 
former remains combined with the water, and 
the latter assumes the gaseous form Neither 
light nor heat has been found to decompose the 
acid gas 

4 I his acid, in the gaseous state or combined 
with water, has a singular effect on colouring 
matter Instead of converting vegetable blue 
into red, as o*her acids do, it abstracts colouis 



COPPER 289 

deposition of the metal from an acidic l or alkaline 2 solution It can also 
be estimated by precipitation as acetyhde from ammomacal, neutral, or 
slightly acidic solutions of cupric salts 3 Another method depends on 
reduction to copper by hypophosphorous acid or alkali hypophosphite, 
and ignition to cupric oxide 4 Hydroxylamme hydrochloride has also 
been suggested as a reagent for its estimation 5 

Numerous volumetric methods for the estimation of copper have been 
described Volhard's process consists in reducing with sulphurous acid 
in presence of a slight excess of ammonium thiocyanate, the copper 
being precipitated as cuprous thiocyanate, and the excess of ammonium 
thiocyanate estimated by titration with silver nitrate in presence of a 
ferric salt as indicator 6 Parkes's method depends on titration of a blue 
cupric - ammonia solution with standard potassium cyanide, the end- 
point of the reaction being indicated by the disappearance of the colour 
Stannous chloride can also be employed in the volumetric estimation of 
copper, a boiling solution of cupric chloride in concentrated hydrochloric 
acid being titrated with this reagent until the yellow colour of the 
solution is discharged In Haen's method an acetic acid solution of the 
cupric compound is mixed with excess of potassium iodide, and the free 
iodine estimated with standard thiosulphate Another process involves 
conversion of the copper into cuprous thiocyanate, and titration of this 
salt with potassium lodate 7 Chloroform is added to dissolve the 
iodine initially liberated, and the completion of the reaction is marked by 
the disappearance of the violet colour of the solution 

4CuSCN+7KIO 3 +14HCl=4CuS0 4 +7KCl+7ICl+4HCN+5H 2 O 

References to other methods are appended 8 

A gasomctnc method for the estimation of cupric salts is based on 
the reduction of cupric ammonia solutions by a hydrazme salt, a cuprous- 
ammonia solution being formed, and the hydrazme oxidized to mtiogen 
and water 

4(CuS0 4 ,5lI 2 0)+N 2 II 4 ,H 2 S0 4 +loNaOH 

=5Na a SO 4 +2Cu a O+28II a O+N 2 

The volume of the evolved nitrogen can be mcasuieel, 9 01 its weight can 
be determined by me ins e>i an apparatus sum] ir to th it employed by 
vou Sehrotter in the estun ition ol carbon dioxiele 10 

1 l<<Kis1u hit !<)<)() 39 J020 /jiilmh J' IcLtrochcm , 1907 13 561 }la\vl(y 
J J n</ and Mm J 1920 no 162 

2 Spit/cr /jcitsrh Elektrodicm 1005 u 545 391 Flamgen / Attur Chem *Sor 
1007 29 4 r > r > 

1 Soddbaum /></ 1807 30 002 3014 

4 1 )alh more P /i arm f 1000 [4j 29 27 J compxn Hanna and Souk up 
ftnw-f/ Chnri 10 1 1 70 282 C'ivi//j Boll chim Juittn 1912 51 4*7 
/dtw/i anal ( I /HHI 10M 52 1 (>LO Hamia ibid 6L6 

r lUyci /jttiw/i anal Chan 1012 51 720 

' Compare Ihcodoi Vlitm Znt 1908 32 889 Kuhn, ibid 105G 

7 )umeson levy ind Wtlls / Ainu ( 1 htm Hoc 1908 30 7(>0 

8 Ooocb indWud Avicr / Mt 1009 62 i48 Jiacovcseu ind Vishuti BW 1000 
42 2638 A bummaty of tlu ipphcations of orgimc co)tipounds to the ostim itiun of 
copper and of othei metals bis been ^iven by Chaston Chapman (Tram Cheni Hoc 1917 
in 20*) 

9 I^bler Zeit&ili anorg Ghent 1005 47 ^71 

10 de Saporta Rev c/en Clnm jnnc (t appl 1907, 10, 338, Poyzi Escot Bull At>wc 
chim Rucr Ditt 1908 26 267 

VOL II 19 



300 OXYGEN WITH HYDROGEN 

obtained , the one a simple rfcunate, and the 
other a hyperoxygenized muriate, in which an 
acid with an enormous quantity of oxygen is 
found, and is hence called hyperoxymunatic 
acid 

1 One very remarkable property of oxymu- 
natic acid has recently occurred to me in a 
courts of experiments upon it Cruickshanks 
had found that if hydrogen and oxymunatic 
acid gases were mixed together, and kept in a 
well stopped bottle for 21 hours, when the 
stopper was withdrawn under water, the gases 
disappeared, and water took their place Be- 
ing desirous to ascertain the time more defi- 
nitely, I made the mixture in a narrow eudio- 
meter, and left it to stand over water , in about 
three quarters of an hour the greater part of 
the mixture had disappeared In the next 
experiment, the gases, after being put toge- 
ther, seemed to have no effect for one or two 
minutes, when suddenly the mixture began to 
diminish with rapidity, like one of common air 
and nitrous gas, except that there were no red 
fumes The diminution went on, till in two 
or three minutes neatly the whole had dis- 
appeared On repeating the cxpeiiment a 
lew hours afterwards no such diminution was 
observed I recollected that the sun had shone 
upon the instrument in the former one , it was 



SILVER 291 

before amalgamation into the chloride, effected by roasting with common 
salt, or by the action of common salt and copper compounds at the 
ordinary summer temperature 

In the patio process the finely ground ore is mixed in a patio or paved 
courtyard with mercury, common salt, and a mixture of copper and iron 
sulphates called magistral, prepared by roasting copper pyrites The 
ore-heap or torta is kept moist The reactions involved are obscure and 
complex, but it is supposed 1 that some of them can be represented 
thus 

Ag 2 S+CuCl 2 =2AgCl+CuS , 

Ag 2 S+2FeCl 3 ==2AgCl+2FeCl 2 +S , 

2Ag 3 AsS 3 +3CuCl 2 =6AgCl+3CuS+As 2 S 3 , 

2AgCl +2Hg =2HgCl +2Ag 

The process of amalgamation requires from a fortnight to a month 
The amalgam is decomposed by heating m retorts 

The pan-amalgamation process has found more favour than the patio 
process The ore in the form of fine sludge is stirred in iron pans with 
a mixture of mercury, common salt, and cupnc sulphate When the 
action is complete, the excess of mercury is drained off, and the amalgam 
is allowed to settle, and then decomposed by heat In the Boss 
system the process is continuous, a series of pans and settlers being 
employed Some silver ores, notably those containing sulphides of 
arsenic, antimony, copper, iron, and zinc, are roasted with common salt 
before mill < mil MM 

Among the older methods is the cauldron or cazo process for ores free 
from sulphur The ore was reduced by boiling with a solution of common 
salt in copper vessels, and then amalgamated In the Franketina 
pioce^s sulphide ores were roasted with common salt, and then boiled 
with a solution of salt in presence of mercury in copper bottomed 
vessels In the KronLe process decomposition ol the ore is effected by 
a hot solution of cuprous ehloiide and common salt, reduction to 
met illie silvci and amalgamation being c fleeted by addition of mereury 
^nd in im ili^im oJ k id or /me In the obsolete iuibcig bmtel process 
sulphide oics were loisted with salt, i,nd imali? imated in lotatmg 
b n ids with mercury, 11011 being added to prevent formation of mereury 
ehl oiicks 

(2) LTXIVIATION 

I he silvc t is dissolved fiom the ore by an iqucous solution of a salt, 
and then pueipitittd is met il 01 sulphide The cyanide process* is 
the most impoitint ol the hxivi ition methods, its ipplieation hiving 
been (onsidci ibly extended m leant y( us, espeei illy m Me\ieo The 
e)re is very (mely eiushed with ey imele solution m i stunp null, and the 
sludge produced submitted to igitition uul aer ition in eontiet with 
ey imele solution Ihe liquid is sepu iteel liom the oie by the aiel of 
meehimeil dlt(rs, inel the silver pieeipit iteel fiom the ele ir solution 
by uldition ol /me in the loim ol elust or sh wings The pioduct is 
smelted with nitre, and is sometimes refined by blowing air through the 
molten mass 

1 Vondratok, Rev de Mctallurgie 1908 5, 678 

2 Calelecott, J Chem Met Minim/ Soc 8 Africa 1908 8 203 266 



302 OX\GEN WITH HYDROGEN 

filled with water when the stopper was drawn 
out under water , but it generally happened 
that the stopper was expelled with violence 

It remains now to point out the constitution 
of this acid All experience shews, that it is 
a compound of muriatic acid and oxygen , but 
the exact proportion has not hitherto been 
ascertained Berthollet, who investigated the 
subject by impregnating \\ater with the acid 
gas, and then exposing it to the solar rays till 
the oxygen was liberated, found it to consist 
of 89 parts of muriatic acid, and 1 1 of oxy- 
gen, by weight Whether all the oxygen is 
liberated in this way is more than doubtful , 
the quantity of oxygen is certainly much under- 
rated Chenevix makes 84 muriatic acid and 
16 oxygen to constitute this acid , he too has 
the oxygen too low , probably because he es- 
timated all the salt formed by this acid to be 
simple muriate, or hyperoxymunate > but there 
is no doubt that oxvmunate does exist in the 
mixture, because it possesses the property of 
bleaching Of all the authors I have seen, 
Cruickshank comes the nearest to the truth , 
he says, 2 measures of hydrogen require 2 3 
measures of oxymunatic acid to saturate them , 
and it is known that they require 1 of oxygen , 
hence he infers, thaf 2 3 measures of this acid 
gas contain 1 measure of oxygen From this 



SILVER 293 

lead by successive additions of zinc, the argentiferous zinc rising in 
crusts to the surface, and being ladled off After liquation to remove 
some of the lead, the zinc is distilled from a retort, the residue consisting 
of lead and about 5 to 10 per cent of silver Where a demand for zinc 
sulphate exists, the zinc is also converted into this salt by oxidation with 
steam and solution m sulphuric acid 

Cupellation is effected by oxidizing the argentiferous lead in a rever- 
beratory furnace with a hearth of bone-ash, marl, magnesia, or Portland 
cement and crushed fire brick, the litharge formed being kept liquid 
by maintaining the temperature above 900 C The litharge and the 
oxides of other base metals flow to the edge of the bath of molten metal, 
and are drawn off By cupellation it is possible to obtain silver con- 
taining only 2 per cent of impurities, but it has often to be cupelled 
again with more lead Different types of cupellation-furnace are em- 
ployed in Great Britain, the United States, and Germany 

In the electrolytic refining of copper (p 249) both silver and gold are 
deposited in the insoluble sludge at the bottom of the vessel, and are 
subsequently extracted from this sludge, the silver being dissolved by 
boiling with sulphuric acid, and subsequently precipitated by copper 

Refining Various methods are employed in refining silver The 
process of parting it from gold is described on p 326 In addition to 
gold, the principal impurities are copper, iron, lead, and zinc 

Physical Properties Silver is a white, lustrous metal, and in very 
thin layers has a violet colour by transmitted light , in thicker layers 
the colour is purple 1 Such layers are produced by depositing a silver 
mirror on glass by the action of sodium potassium tartrate on an 
ammomacal solution of silver nitrate 2 Reduced silver in the form of a 
fine powder has a grey, earth-like appearance 3 The metal crystallizes 
in octahedra belonging to the cubic system The density of the un- 
rolled metal is 10 4923 , that of the metal after rolling, 10 5034 4 Its 
melting-point is given as 958 3 C , 5 960 C , 6 960 5 C , 7 960 9 C , 8 
961 C , 9 961 5 C , 10 and 962 C , n and its boiling point as 1955 C , 12 and 
2040 C 13 at 760 mm With the exception of gold, it is the most malleable 
and ductile of the metals, and can be hammered into leaves 0025 mm 
thick Its conductivity for heat and clcctucity is highci than that of 
any other substance Its specific heat is given as 05535, 14 0557, 15 and 

I Houlk vigiu Cotttpt tend, L909 149 1 J08 GomjM.it J uniei Ptoc Roy SOL 190& 
[A] 8 i 301 

Compile Kohlschuttcr Annahn 1012,387 80 

J Cunipaic Piss ujewsky, J 2lu&& Phy<> Chun tioo 1908 40 U>7 Zctlsch anotg 
Cham 1008 58 399 

1 Kihlbium Uoih mdSicdki ibid 1000 33 35 i 
Day ind (lenient Amer J tid 100S [4J 26 405 
( Diy and busman ibid 1010, [4] 29 93 

7 Hey( oc k and Neville Trans Cham Sot 1895 67,1024 Dun uul l<ootc, Tiam 
l<madayho( 1020 15 ISO 

8 Wtudmi md Bury ss Hull Bureau Mw/wfrw/s 1909 6 B9 

9 (hicitlci mdPadni Zeitith Melalll nude 1910 II 1 
10 Oucrogh Zcitsch anon/ Chem 1910 68 301 

II Bdthelot Ann Chtrn Phy<> 1002 [7J 26 58 

12 (Jucnwoocl /Kitsch hhl troche in 1912 18 3L9 Prot hoy #oc 1909 [A] 82 
300 eompaie^w/ 1010 [A] 83 483 

13 Hxnscn Btr 1909 42 210 compare von Wallenberg Ztitsdt anoig Chun 1908 
56, 320 

14 Brunstod Zeitsch Mektrochem 1912, 18, 714 

15 Schimpff Zettech physikal Chem, 1910 71 257, compare Magnus Ann Phy&ik, 
1910, [4] 31 597 Richards and Jackson, Zeitsch physikal Chem 1910 70,414 



JO* OXYGEN WITH HYDROGEN 

methods always deposit some brown oxide of 
manganese when treated with ammonia, but 
that obtained by the last deposits none The 
action of muriatic acid on hvperoxymunate of 
potash, evidently consists in detaching the 
superfluous oxygen from the compound, and 
not the hyperoxvmunatic acid particle from the 
particle of potash 

As the oxymunatic acid is of great and in- 
creasing importance in a theoretical as well as 
practical point of view, I have spent much 
time in endeavouring to ascertain the pro- 
portion of its elements, and have, I think, 
succeeded , at least, I am pretty \\ell satisfied 
myself as to its constitution the methods I have 
taken are both synthetical and analytical, but I 
chiefly rely upon the latter 

1 I filled a eudiometer with dry mercury, 
and sent up 13 water gram measures of muri- 
atic acid gas, to which were added 9 me isures 
of oxygenous gas of 77 per cent purity, which 
consequently consisted of 7 ox) gen ind 2 azote 
The instrument had platina wnes About 
noo small electric shocks were passed thiough 
the mixture of gases , a gradual diminution 
ensued, the mercui) b^c uiie foul, the same 
as when oiymiirial'c i^d is in contact with it 
The 22 measures were reduced to 4, which 
were not diminished by Washing 1 o these 4 



SILVER 295 

preparation, and partly on the age of the specimen x Reduction of the 
monoxide by 60 per cent formaldehyde at 35 C yields a very stable 
solution of colloidal silver, varying in colour from pale-lilac to rich 
ruby-red 2 The effect is not produced by employing acetaldehyde 
In presence of Irish moss, hydrazme hydrate yields colloidal silver 
varying in colour from dark-reddish brown to brownish yellow in trans- 
mitted light The more dilute solutions thus prepared are very stable, 
and can be kept for two months By this means it has been found 
practicable to prepare solutions containing 17 per cent of colloidal 
silver, but such concentrated forms lack stability 3 The colloidal solu- 
tion decomposes hydrogen peroxide slowly 

Colloidal silver can also be prepared by forming an electric arc 
between silver poles immersed in water, the solutions being brown with 
a low current, and green with a stronger current 4 The electric con- 
ductivity of the solution produced by the second method is higher than 
that of the brown solution Addition of an electrolyte also converts 
the brown solution into the green form 5 The conductivity of such 
solutions has been attributed to the presence of silver oxide 6 

When silver is boiled with water for a prolonged period, a colloidal 
solution is formed It contains 0162 gram of silver per 100 c c 7 
Another procedure involves heating the metal to redness or a higher 
temperature and plunging it into cold water 8 Many other methods of 
preparing colloidal silver have been described 9 

Plates of copper or zmc precipitate colloidal silver from solution 10 
The solid forms are brittle, and amalgamate with mercury Acids 
convert them into grey silver, without evolution of gas 

A therapeutic preparation of colloidal silver is known as " collargol " 
Credo's ointment also contains this form of silver, and is employed m 
the treatment of certain types of septic infection An astringent 
antiseptic is prepared by the action of an alkaline tannin solution on 
aqueous solutions of silver salts u 

In photography colloidal silver plays an important part, an instance 
being the image produced in the ordinary printing-out process 

Neithei the metal nor any of its salts displays radioactivity 12 

Chemical Properties At the ordinary temperature silver is stable 

1 ( nmjuic Horn lot Uoni.pt itud, 1903 137, 122 Buncioft J Physical (Jhuti , 1919, 
23 554 

' 2 Pickles Chem New*> 1018 117 358 

Cutbici Wolf and Kicss Kolloid dwlsch , 1922, 30, 31 

4 Biedig ZcU^cfi arujcw Clum 1898 1 1 951 

G Compile Woudstia Zdtuh pfiysifcal C/um 1908 61 607 Lotttrmosu ibid 
62 284 lltbiLic Cowpt r<nd 1912 154 1540 

lltbicH (Jompt rend 1900 148 354 

7 Ji uibi Mtrigaimi ind Seal i Atti R Accad 1 mc<i 1900 [5] 18, i 542 

8 Kimuia Mctn Coll Rci 1 J nq Kyoto 1013 5 211 

Schneider Mr 1801 24 3 HO 1892 25 1H>4 1281 1440 JUi us and Schneider 
Zeitwh phyukal Chan 1891 8 278 Wied Annalcn 1893 48 557 Obcibcck ibid 
745 I ottcunosci and Moyor J ptaLt Ghcin 1897 56 241 189b 57 r >40 1 otUnnosir 
ibid 1905 71 20(> Blake Ani(r J Sci 1005 16 282 Chassivint hall tioc (him > 
1904 31, 11 Pxil Bcr 1902 35 2200 Kuspcrt Mr , 1902 35 2815 4000 4070 
Gutbicr and Hofmeici //dtuh anory Chem 1905 45 77 Castoro Gazzctta 1907 37 
i J91 Zidtsch Ghent Ind Kolloidc 1910 6 283 KohlachutUi Zcitsch hltltrochem 
1908 14 49 /Jdluh Ghcm hid Kolloidc 1913 12 285 (summary) Pierom Oazzetta 
1913 43 i 197 

10 Plulipson ZeihcJi Client Ind Kolloidc 1912 n, 49 

11 Sensburg German Patent 1909 No 208189 

12 Levin and Ruer Physikal Zeitsch , 1909, 10, 576 



306 OXYGEN WITH HYDROGEtf 

of hydrogen require 34- of the acid to saturate 
them I have found the results a little differ- 
ent , but the error is not much, and is what 
might be expected Whether we treat oxy- 
muriatic acid over mercury or water, we are 
sure to lose some of it , and unless the loss can 
be estimated and allowed for, we are apt to 
overrate the acid required Before the action 
of light on this mixture was discovered, I used 
to mix known quantities of the two gases to- 
gether, in a graduated eudiometer of Volta, 
over water, and, after letting the mixture 
stand a few minutes, in order to a complete 
diffusion, I passed a spark through, but no- 
ticed the moment before at what degree the 
mixture stood , in this Way, when there is an 
excess of hydrogen, the results are accurate , 
the total diminution can be found, and the re- 
siduary gas can be analyzed to find the hy- 
drogen left, and the common air (if any), 
which is extremely apt to be found in a greater 
or less degree, in all oxymunatic acid obtained 
over water By frequent careful trials, I found 
that a measure of hydrogen required as near 
as possible an equal measure of the acid to sa- 
turate it But since the effect of solar light 
was discovered, I have operated in a more 
simple and elegant manner , and the results 
appear rather more uniform nnrl 



SILVER 



297 



21594=2X10797 (O=16) In 1808 Dalton preferred the value 
Ag=100 (0=7), in 1817 Memecke selected Ag=108, and m 1826 
Gmelin gave the same value for the equivalent of the metal 

In the section on the atomic weight of sodium (p 87) mention is 
made of the close relationship between the atomic weight of this element 
and the atomic weights of silver, potassium, chlorine, bromine, and 
iodine In the sections on the atomic weights of sodium and potassium 
(loc cit , and p 155) an outline of the general principles underlying the 
methods adopted by the earlier investigators m determining the atomic 
weights of these elements is given, and the experimental results of a 
number of researches are summarized Here it will suffice to describe 
the determination of ratios not previously mentioned As with sodium 
and potassium, the experimental work naturally falls into two mam 
divisions (1) that of the early investigators, and (2) that carried out 
under the extremely accurate conditions required of modern atomic- 
weight research 

In connexion with the early work, only a summary of results need 
be given The values for the various ratios AgXO 3 AgX are stated 
in the table 



Experimenter 



Year 



Ratio 



Marignac l 
Stas 2 



Stas 3 

Millon 4 
Stas 5 



AgC10 3 30=100 x 

1843 x =25 083 00041 

1865 =25 0795 0010 

Mean (Clarke) =25 0797 0010 
AgBrO 3 3O=100 x 

1865 | #=20349 00014 

AgI0 3 30=100 d 

1843 

1865 



#=17047 0005 
=16 9747 00009 



Mean (Clarkc)=16 9771 0009 



Dctcimm itions of the ratios Ag AgX arc moic numerous The 
next table surnman/es the lesults 

1 MUI^TUK (I 1 nut s ccnnjildt s (Umvti 1902 I 80 

Stas (]'nnc>((>nt]>l(t(<> Bnissilh J8<)4 I (>45 
1 Stis ilnd (>i r > 

1 Mjllon \HH Chun yV/ys 184} | J] 9 400 
f fetas (L u /;/ CA complete s I^iusscls 1894,1 028 



[lABLL 



308 OXYGEN WITH HYDROGEN" 

oxy muriatic acid gas to convert them into 
water In every one of the experiments, the 
acid was less than the hydrogen 

The above experiments are highly amusing 
in a day of clouds and gleams , the presence 
of the direct solar light instantly gives the mo- 
tion of the mercury a stimulus* and it as 
quickly abates when a cloud mcervenes The 
surface of the mercury in the tube always 
becomes fine sky blue during the process , and 
so does liquid ammonia that has been used to 
decompose oxymunatic acid , I do not know 
what is the reason m either case 

From the results above, it appears that 100 
measures of oxymunatic acid gas must consist 
of 53 measures of oxygen, united to a certain 
portion of muriatic acid gas Now, ICO cubic 
inches of oxymunatic acid gas weigh 72 or 73 
grains, and 53 inches of oxygen weigh about 
18 grains, which is rather less than ^th of the 
above Hence, if the atom of muriatic acid 
weigh 22, that of oxymunatic acid must weigh 
29 , and thus we obtain the constitution of this 
last acid An atom of it consists of one of 
muriatic acid and one of oxygen united , the 
former weighs 22, the latter 7, together mak- 
ing 29 , or about 76 muriatic acid, and 24- 
oxygen, per cent Thus, it appears, that the 
former experiments on the specific gravities of 



SILVER 299 

For silver sulphate Stas l found the precentage of silver to be 
69 203 0012, and Struve's 2 result was 69 230 004 According to 
Clarke, the weighted mean is 

Ag 2 S0 4 2Ag=100 6920500011 

Computation of the atomic weight of silver from the data cited in- 
volves a knowledge of the mean values for the ratios KC1 30, KBr 3O, 
KI 30, NaCl 30, Ag KC1, Ag KBr, Ag KI, and Ag NaCl, as 
determined by the early workers These values are given in the sections 
on the atomic weights of sodium and potassium (pp 87 and 155) The 
two early determinations of the ratios RX AgX lack accuracy, and 
are omitted 

Combination of the various ratios gives 

x -s! A = lor 9270 106 w 



X = A ^ 108 196 008 ^ (2) 



R 

Ag=10766600278 (3) 

=f5 Ag=10791900079 (4) 

=^ Ag=10793900050 (5) 

r=^ Ag=10793000092 (6) 



X = Ag=10790600062 (7) 

Ag=l()7 9620 0090 (8) 

rt v ' 



Results (2) and (3) differ sufficiently from the others to compel then 
i ejection The arithmetic mean of the other six results is A<r 107 93 
With the exception ol (4), they depend mainly on the woik ol Stas, and 
when his ic suits only are employed in the caleulations the same mean 
value is obt lined, but the individual results aie more eoiicoidant 

J)e spite the i^recment of these results, they are now known to be 
very erroneous, 3 although the v ilue A^ 107 9e3 was given in the Inter 
nation i[ Atomie Weight Committee's table down to 1908 The piob 
ability ol the coneet result being nearer to 107 89 01 107 88 was 
mleried by Guye 4 in 1905 as a necessary consequenec oi ehangmg the 



** com pit It** .Biusscls 1894 I 410 
btiuvc Annalcji Ib51 80 203 

a I<oi ciitidsrns of Iho work of Stas icfcrcnco should bt made to the papois by 
Hichxrds and others cited later particulaily the paper by Kichaids and Wells ( ompa-ic 
alao Duinis Ann C/nm Phy** 1878 [5| 14 280 St is O J UMC* com pick ^ Jiiusstls 
1S94 3 iOu Dubiuul (Jompt rend 1908 147 8% HOI) Ball Hoc chitn I00 ( ) [4] 5 
200 31 J 341 1049 1 cduc Co nipt rend 1908 147, 972 1909 148 42 Himicha 
ibid 1908 147 1302 

1 (Juyo Arch 8ci phys nat 1905 [4] 20, 351 Bull Soc chim 1905 fi] 33 1 , 
J Chim i>hyt> 1906 4 174 Chem News 1906 93 35 , Guye and lor Oazanair Compt 
rend 1906 143, 411 , Guye and Gcrmann, J Chim phys , 1916 14 204 



310 (m GEN WITH HYDROGEN 

alkalies and earths, by sending a stream of oxy- 
munatic acid gas into solutions of these ele- 
ments, or of their carbonates in water The acid 
combines with the alkali , but in process of 
time, as the solution becomes concentrated, a 
change takes place in the acid , one atom of 
oxymimatic acid seizes upon an atom of oxy- 
gen from each of Us neighbouring particles, 
and reduces them to ordinary muriatic acid , in 
this state it forms with an atom of alkali an 
hyperoxymunale, whilst the other atoms of 
acid form muriates It seems that the oxymu- 
nates are difficultly attainable , because, as 
their solutions are concentrated, they are so 
apt to be resolved and compounded again, as 
above 

BerthoHet first pointed out the peculiarity 
of this acid but its nature and properties were 
more fully discussed by Hoyle in 1797, and by 
Chenevix in 1802 These authors made their 
principal experiments on hyperoxymunate of 
potash , they nearly agree as to the constitu- 
tion of the salt, but differ in some of the cir- 
cumstances of its production It yields by heat 
about 2 or 3 per cent of \\atcr, about 38 per 
cent of oxygen, and 59 or bO of a salt unal- 
terable by heat, which Chenevix considers as 
simple muriate , but Hoyle says it exhibits 
traces of oxymunatic acid bv sulphuric acid 



SILVER 301 

-=^=0 64382X0 691069, 

=0444924, 
=48 107884, 

01 Ag=101 884 

A similar method of calculation can be applied to the results of 
Richards and Willards's analyses of lithium chloride and lithium per- 
chlorate, as indicated in connexion with the atomic weight of lithium 
(p 57), it gives Ag=101 871 

Another calculation of the atomic weight of silver can be made from 
modern determinations of the ratios 2Ag I 2 5 and Ag I 



- 

Ag \ \2Ag I / J 2Ag 

The lodme-pentoxide ratio was very carefully determined by Baxter and 
Tilley 1 in 1909 to be 

I 2 O 6 2Ag=100 646230, 

and the composition of silver iodide was found by Baxter 2 in 1910 to be 

Ag 1=100 1176601 

Combination of the two ratios gives the value Ag=107 864 

In 1913 Scheuer 3 dissolved silver in sulphuric acid, collected and 
weighed the sulphur dioxide evolved, and dried, fused, and weighed 
the silver sulphate 

2Ag+2H 2 S0 4 =Ag 2 S0 4 +S0 2 +2H 2 

The weights are m the ratios 2Ag Ag 2 S0 4 SO 2 , and the atomic weight 
of silver is readily calculated, since 

_ _ 2Ag _ ___2Ag 
Ag 2 SO 4 2Ag-SO 2 ~~ 2*J 

The mean of five experimental results gave Ag=107 884 

The modem values for the atomic weight of silver vary between 
1 07 8C4 aid 107 884 The < ui u nt table of the International Committee 
on Atonuc Weights gives Ag=10788, but possibly 10787 is a better 
dppi oximatioii to the true value, as has been pointed out by Guyc 4 
As an essential laetor in the caleulation of many othc r itomic weights, 
the itomie weight ol silver is ol fundamental impoitance 

ALLOYS AND COMPOUNDS Ol< SI L VLB 

Alloys 5 A dc senption of various alloys of silver with copper ind with 
gold 6 has been given by seveial authois 7 British silver coin and stan- 

1 I>iUd and Lilky / Inur Cluni tfoi 1909 31 201 
IU\tu ibid 1910 32 15<)1 compile liaxtei ibid 1904 26 1 V77 1905,27,870 

1 Schdid \rch h<i ;>//?/ s tml 19M [4] 36 J81 

4 (>uy< / Chim phys 1917,15,549 1 ( )1 ( ) 17, 171 
!<<>r silvci amalgam ^eo this sen os Vol 111 

( Compare j)p 297 401 335 and 3 J6 

7 Kumakoll UN! S(!u mtsdiushiiy J RUA<> Pliys Chun Soc 1908 40 1067, 
Ltpkowski Zutwh anonj Chem 1908 59 285 Kurnakott Pusdim and Scnkowski, 
/ Itiw J>hys Chem #06 1910 42,733 Zettsch annrq Chem 1010 68 J23 Waidner 
and Buigoss Bull Bureau of Standards 1909 6 149 Janeckc Zeitsch anqew Chem , 
1912, 25, 935 (summary of previous work) Eaydt Zeitsch anonj Chem 1912 75 58 



312 OXYGEN WITH HYDROGEN 

and 25 of the latter Hoyle does not inform 
us on this head , CheneviK found 84 of the 
former and 1 6 of the latter Here then is some 
obscurity The fact, I believe, is, that there 
is always a greater or less portion of real oxy* 
muriate of potash amongst the salts formed, or 
in the mass which Chenevix calls the entire 
salt Oxymunatic acid precipitates silver from 
nitrate as well as muriatic , and as this was the 
test, it is evident Chenevix must have con- 
founded a quantity of oxymurrate of potash 
with the muriate The quantity may even be 
ascertained For, if 25 75 16 48 In 
100 of Chenevix's entire salt, there were then 
16 hyperoxy muriate, 48 muriate, and the rest 
or 36 must have been oxymunate Hovle's 
experiments confirm this conclusion , for, he 
observes that the remaining muriate (after the 
hyperoxyraunate was abstracted) was consi- 
derably oxygenized, since with the addition of 
acids it became a powerful destroyer of vege- 
table colours This could not be the case with 
a muriate, nor even a mixture of muriate and 
hyperoxvmunate Besides, it is well known 
that the oxymunate of potash (or oxymunatic 
acid absorbed by potash) was largely used for 
the purpose of bleaching , now if the acid had 
immediately resolved itself into muriatic and 



SILVER 303 

phous precipitate of silver chloride, which can be converted into a 
crystalline form by evaporating its solution in concentrated hydrochloric 
acid or ammonium hydroxide The native variety is known as horn- 
s^lver 9 and crystallizes in the cubic system Its density is 5 31 to 5 55 
The crystalline form is also produced by slow diffusion of a solution of 
hydrogen chloride into one of silver nitrate Its cubic crystals are 
isomorphous with those of silver bromide 1 

The melting-point of amorphous silver chloride is given as 451 C , 2 
452 C , 3 and 455 C , 4 the substance fusing to a yellow liquid After 
solidification its density is 5 45 to 5 59 The specific heat is 08775 5 
At 18 C its solubility 6 is 1 17 X 10~ 5 gram-molecules per litre of water, 
and at 25 C , 1 6X 10~ 5 Silver chloride also dissolves in solutions of 
ammonia, 7 sodium thiosulphate, potassium cyanide, mercuric nitrate, 
and in concentrated hydrochloric acid and saturated chloride solutions 
For the heat of formation from the elements Berthelot gives 29 2 Cal , 
and Thomsen 8 29 38 Cal Wolff 9 considers their results too low, and 
gives the value 30 612 Cal , that stated by Braune and Koref 10 being 
30 41 Cal The intermediate value 29 940 Cal is given Jby Fischer u 

Chlorine reacts with an aqueous solution of silver nitrate to form 
chloride and chlorate of silver, the hypochlorite being an intermediate 
product 

6AgNO 3 +3Cl 2 +3H 2 0=5AgCl+AgClO 3 +6HN0 3 

Silver chloride absorbs gaseous ammonia, forming double compounds 
of the composition 2AgCl,3NH 3 and AgCl,3NH 3 The first crystallizes 
in rhombic plates from ammoniacal solutions of silver chloride 12 , the 
second is formed in long prisms by heating the chloride with a saturated 
aqueous solution of ammonia under pressure 13 The dissociation- 
pressures of these compounds have measurable values 14 Other com- 
pounds of similar type with the formulae AgCl,3NH 3 (9 16), AgCl,l|NH 3 
(10 52), and AgCl,NH 3 (11 11) have also been prepared, 15 the figures in 
parentheses giving the calculated heats of formation in large calorics 
The interaction at 200 C of lodic acid and ammoniacal solutions of the 
chloride to form silver iodide has been the subject of investigation 16 
A cold cimmoniacal solution of sodium peroxide reduces silver chloride, 17 
and it is ilso i educed to the metal bv the n-etion of 7ine in the comsc of a 

1 Kumuknft and bchcmtschushny / Tfom Phy^ Ch(w Hoc 1908 40 1007 
SclurntHchushny ibid 1910 48 2(H 

3 Moukcmcyii Jain Miti Bid M 1909 22 1 

4 Piuthc /iLitbdi anory Ohcm 19 12 76 101 

5 Bionskd Ztiterlt Mdctrochon 19J2 18 714- compile Mxgnus Awn Pkynl 1910 
[4] 31 597 

Hoik man Zcil^ch phi/nl al CJiem 1893 12 125 Kohl? 111 sch and .Rose ibid 
214 compile Hill / Annr Chan, flor 190S 30 OS Kohli uisrli 7n/sr// pln/wJ al 
Chun 1908 64 129 vxnllosstm Clum Wukblad 1912 9 J% 

7 Comput IMdM Her 1908 41 *17 r > 

8 1 homs< n Thrrn)0(h(nn\lnj (Longmans 1908) 2S4 

9 Woltt /jdluh lil(Htoch(m 1914 20 19 

10 l>i IUIK unl Kot(f /jdlwh anouj (Vum 1914 87 170 

11 InisiluF AitHb tldttrotliem 1912 18 28} 

12 Kim Ann Chun / J %s 1840 72 290 
n hiuil Compl rend 1884 98 1279 

14 Isimbtii ibid 18()8 66 1529 Horstmann, Ber , 1870 Q 749 Biltz ZtihUi 
phynlal Glicm 1909 67 561 

15 BUt/ and Stollenwerk Zeitwh anorq Chem 1920 114 174 

16 Baubigny Compt rend 1908 146 1097 

17 Booth, Chem News 1911, 103, 288 



314 OXl GENT WITH T" rt"()(, 



rushed, but only a small quantity , that when 
no fames appear, no diminution takes place , 
they hence conclude, that this acid gas is am 
excellent test of the presence of hygrometnc 
water [steam] in gases , and observe that all 
gases contain such, except fluoric, muriatic, 
and probably ammoniacal Berthollet, jun 
has proved the last mentioned gas to contain 
no combined water , and Gay-Lussac and 
Thenard suspect it contains none hygrometn- 
cally , but some experiments of Dr Henry con- 
vince me that it does, and I thmk its not 
fuming when mixed with common air is a 
proof of it They obseive, that when \vater 
is saturated with fluoric acid gas, it is limpid, 
smoking, and extremely caustic 9 that heat 
expels about one fifth of the acid % and the re- 
mainder becomes fixt, resembling concentrated 
sulphuric acid, and requinng a high tempera- 
ture to boil it They query from this fact, 
whether sulphuric and nitnc acid are not na- 
turally gasiform, and owe their liquidity to 
the water combined with them They exposed 
a drop of water to 60 cubic inches of fluoric 
acid gas , the drop, instead of evaporating, 
was increased m volume, by the absorption of 
the acid , and hence the) conclude, that flu- 
one acid ga^ is also free from combined water, 
the conclusion it, extended to ammoniacal 



SILVER 305 

photo chlorides are characterized by their great sensitiveness to light, 
blue light producing a blue coloration, and red light a red coloration 
This action is reversible, the blue coloration being transformed into red 
by the action of red light, and so on This phenomenon is inapplicable 
to the production of colour-photographs, for white light causes a darken- 
ing in colour 

There are several theories as to the constitution of the silver sub- 
halides in the latent image The molecular theory regards the subhahdes 
as definite chemical compounds The adsorption theory regards them as 
adsorption-compounds of colloidal silver and subhahdes The molecular 
theory is advocated by Tnvelli, 1 who considers the colour-changes to 
indicate the existence of several silver subhahdes, which yield solid 
solutions with each other and with the silver hahdes He also regards 
the mechanism of " reduction " with ammonium persulphate as favouring 
the molecular theory 

Light reacts with silver hahdes, producing a series of subhahdes 
containing a diminishing proportion of halogen, the colour-changes 
taking place for all the hahdes in the sequence green, bluish-green, blue, 
violet, red, orange, yellow 2 Guareschi 3 has noted that the darkening 
of silver salts by light was observed before the time of Boyle (1663), 
and that investigations made by Schulze (1727), Beccan (1757), and 
Scheele (1777) were very important for the development of photography 
In a more recent paper, Boruttau 4 states that the colour changes under- 
gone by silver salts under the influence of light were first mentioned by 
Konrad Gessner m 1565 in his work De omm verum fossilium genere 
hbn ahquot, where the darkening of native horn-silver is cited Hydrogen 
peroxide has no action on silver bromide, but with the green, blue, or 
red photohalide oxygen is immediately evolved, with formation of silver 
bromide and silver monoxide 5 

Luppo Cramer prefers the adsorption-theory because the red, blue, 
or violet photohahdes are formed from the hydrosols of the silver hahdes 
m presence of colloidal silver by precipitation with any electrolyte, and 
treatment of the resulting gel with nitric acid He attributes the action 
to adsorption of colloidal silver by the gel of the normal silver halide 
He states that identical silver hahdes are produced by the action of 
light on silver chlondc and bromide, and regards the assumption of the 
existence oi subh ihcles is unjustifiable 6 An investigation ol the ution 
ofli^ht on silver hihdes his been nrude by IPiitung 7 with the ud o( the 
mierobnl vncc , and has fmmshcd evidence in suppoit ol I uppo ( i imcr's 
view On exposure to li[ht ind air, silve i bionncle loses 2 !< pel cent 
ol its totil bromim , its e oloni e h in#in# fiom p lie yellow to p ilc purple , 
but exposure to the ution of bromine in ibsence of light lestoies the 
origin il colour the initi il weight being rcgumd ilmost eemipletely 
In xir, silver e hle>riele loses 4 1 pci cent of its oluoimc, ami in viemim 
810 per cent, the ongm il weight being reslouel by the ution of 

1 luvcili Zeitu/i wits PJiotoqiaphie 1908 6,358 438 

2 fnvollj Pror K Aiad Wetcnsrh Amsterdam, 1900 II 730 

3 Guarc&chi Ath R Accail Sci Torino 19J4 49 1083 

4 Boruttiu Zeitsch anqew Chem 1918 31 139 

5 frivolli Chem Weekblad 1909 6 525 compare Tnvelli ibid 1910 7 321 404 
fiettsch ws<? Photographic 1911 9 185 

G Luppo Ciamer Zeitsch amjew Chem 1909 22 2330 compile T uppo Cramer, 
Zeitsch Ind Kolloide 1910 6 7 168 7 42 99 304, 1911,8 42 
7 Haitung Trans Chem 8oc , 1922 121, 682 

voj n 20 



316 OXYGEN WITH AZOTE 

They seem to think that the acid is de- 
composed in this case but they have not 
advanced any opinion, that either fluoric or 
muriatic acid gas consists entirely of hydrogen 
and oxygen 



SECTION 2 

OXYGEN WITH AZOTE 

The compounds of oxygen with azote, hi- 
therto discovered, are five , they may be dis- 
tinguished by the following names , nitrous 
gas, nitric acid, nitrous oxide, nitrous acid, 
and oxymtnc acid In treating of these, it 
has been usual to begin with that which con- 
tains the least oxygen, (nitrous oxide) and to 
take the others in order as they contain more 
oxygen Our plan requires a different prin- 
ciple of arrangement , namely, to begin with 
that which is most simple, or which consists 
of the smallest number of elementary particles, 
which is commonly a binary compound, and 
then to proceed to the ternary and other higher 
compounds According to this principle, it 
becomes necessary to ascertain, if possible, 
whether any of the above, and which of them, 
is a binary compound As far as the specific 



SILVER 307 

lodic acid into the iodide l Double compounds with ammoma of the 
formulae AgBr,3NH 3 (8 64), AgBr,lJNH 3 (9 95), and AgBr,NH 3 (10 65) 
have been prepared, 2 the figures in parentheses indicating the calculated 
heats of formation in large calories 

The action of light is similar to that on silver chloride, silver photo- 
bromide being produced with liberation of bromine 3 The change in 
weight under the influence of light does not exceed 2 4 per cent 4 
Silver bromide is more sensitive to light than any other substance, 
and is extensively employed in the manufacture of dry photographic 
plates The glass is coated with an emulsion produced by addition of 
ammomacal silver nitrate to a solution of potassium bromide containing 
gelatin, the mixture being digested at 40 to 45 C for about an hour 
to increase the size of the bromide granules 5 The emulsion is solidified 
by cooling with ice, washed with water, liquefied, and poured over the 
glass It is usual to add a small proportion of silver iodide as a de 
celerator, and a slight excess of potassium bromide to eliminate silver 
nitrate 

A short exposure in the camera to light produces the " latent image," 
the process being attended by slight reduction, and the formation of 
photobromide, probably a solid solution of silver and silver subbromide 
in silver bromide 6 The latent image is developed by immersing the 
plate in an alkaline reducer, such as pyrogallol or qumol, in presence of 
alkali The reduction takes place first at those points where it has been 
initiated by the action of light Development must not be continued 
so long as to cause general blackening of the plate or " chemical fog " 
When it is complete, the image is " fixed " by dissolving the unaltered 
silver salt in a solution of sodium thiosulphate The velocity of re 
duction is lowered by the presence of bromine ions, so that the operator 
can control the rate of reduction by addition of a solution of potassium 
bromide to the developer 

Collodion can be substituted for gelatin in the preparation of the 
emulsion, but the plates are less sensitive than the gelatin plates 
Gelatin exerts a reducing action on silver bromide, but collodion does 
not , the collodion plates arc consequently free from the trace of fog 
eharactemtie of gelatin plates, and therefore give a very sharp, well- 
defined image suitable for technical ropi eduction Collodion plates are 
rendered more sensitive by the prescnee of silver nitrate m the emulsion, 
but sue h pi ites h ivc to be expose d in the wet condition, and arc not well 
id ipte el for field work The increase in sensitiveness depends on the 
reietion 



Silvci bromide is most sensitive to blue light, but ean be rendered 
sensitive to the icen, red, and ultra-red portions of the spectrum by 
dyeing the emulsion with members of the cosm group or the cyanme 

1 lUubigny fompl rend 1908 146 1007 

2 .Bill/ Mid Stolknwoik Znkch anoty Chem 1920 114 174 

3 On tho hbontion of bromine by sunlight compart Soli war/ and Stock Her 1021 
54 [B| 2111 

If i _ Trans Chem Soc , 1922 121 G82 , compare Koch and fechrader, Zeitscli 
I Jl 6 127 

5 Cohen Eder s Jahrbuch 1895 103 Fder Handbuch der PhotoqrapJne Halle 1893 
Part III Abcgg and Herzog Arch wis? Phot 1900 I 115 Baur and Postius Physilal 
Zeitsch 1902 3 491 

6 Compare Wcisz Zeitsch physikal Chem 1906 54 305 



SIS 



OXYGEN WITH 



Sp gi 
Nitrous gas I 102 

lulr oxide I 614 
Nitre acid 2 4 14 


constitution by weight 
40 G azote + ?3 4 oxy 
442 \-55 8 


Ratios 
6 1 7 
557 
5 1 7 
2X6 1 7 
2X577 
2X5 47 
5 87X2 
597X2" 
547X2 
477X2 


Daxv Cavendish 


63 5 j- 30 3 

t^n ^ i <?Q , 


01 +39 

/m a l TI"> ft . . .. 




no .,! 7*> 


2^, j [-74 



The above table is principally taken from 
Davy's Researches where two or more result* 
are given under one article, they are derived 
from different modes of analysis In the third 
column are given the ratios of the weights ot 
azote and oxygen in each compound, derived 
from the preceding column, and reduced to 
the determined weight of an atom of oxygen, 
7 This table corroborates the theoretic views 
above stated most remarkably The weight 
of an atom ot azote appears to bt between 5 4 
and 6 1 and it is worthy of notice, that the 
theory does not differ more from the experi- 
ments than they differ from one another , or, 
in other words, the mean weight of an atom 
of azote derived from the above experiments 
would equally accommodate the theory and 
the experiments The mean is ^0, to which 
all the others might be reduced We should 
then have an atom of nitrous gas to weigh 
12 6, consisting of 1 atom of azote and 1 of 



SILVER. 309 

as 138 Cal, 1 U3 Cal, 2 1457 Cal, 8 151 Cal/ 15158 Cal, 5 and 
15 17 Cal 6 

Silver iodide is only slightly soluble in ammonia, but dissolves in 
sodium thiosulphate, concentrated hydnodic acid, and saturated 
solutions of potassium iodide 7 It forms a series of double salts with 
silver bromide, 8 with mercuric iodide, 9 and with the iodides of the 
alkali metals 10 Double compounds of silver iodide and ammonia of 
the formula AgI,3NH 3 (692), AgI,lNH 3 (725), AgI,NH 3 (856), 
AgI,2NH 3 (705), and AgI,iNH 3 (1159) have also been prepared, 11 
the figures in parentheses indicating the calculated heats of formation 
in large calories 

Like the other silver halides, silver iodide is sensitive to light, the 
loss m weight not exceeding 1 1 per cent 12 The sensitiveness to light 
is diminished by the presence of potassium iodide, and increased by 
that of silver nitrate In the second instance the liberated iodine reacts 
with the silver nitrate 

6AgNO 3 +3H 2 0+3l 2 =5AgI+AgI0 3 +6HN0 3 

The possibility of developing the latent image was discovered by 
Daguerre, who at first employed a silver plate coated with the iodide, 
development being effected by exposing the plate to the action of 
mercury- vapour Later, he substituted glass for silver, and developed 
with a mixture of silver nitrate and ferrous sulphate His discovery 
led to the introduction of the wet collodion process with silver iodide as 
the sensitive material 

Silver hypochlonte, AgOCl A very unstable solution of the hypo- 
chlonte is formed by the action of chlorine-water on excess of silver 
monoxide It soon decomposes into silver chloiide and chlorate 

Silver chlorite, AgClO 2 Silver nitrate and potassium chlorite leact 
to form yellow crystals of the chlorite, an unstable substance decom 
posing ciieigctically at 105 C 

Silver chlorate, AgC10 3 The chlorate can be prepared by dis- 
solving the monoxide in chloric acid, or by passing chloune through 
a suspension ol the monoxide m watci, the hypochlonte being an inter- 
mediate pioduct It forms till ir<ni il crystals, melting at 230 C, 
and decomposing at 270 C into silver chloride and oxygen At 
oidinaiy tcmpciaturcs its solubility is 20 grams pei 100 grams of 
w itc i 13 Its solution in ammonium hydioxide yields piismatic crystals, 
j, melting at 100 C 



1 IhnmsMi Tkitinoihum^Lt y (\ ongmans 1008) 284 

LCI the lot Ann Ctum /'%s 188$ [5J 29 241 
a Joricscmdlfd.it/Miuin / Atntr Chun hoc \. ( )l r y 37 752 

1 Bi IUJK uid Jvouf /i<ih<h anortj ('/urn IOLJ- 87 17 r > compare la-yloi and 
\iiclciBou J Amu Chcm Noc 1921 43 2014 

Goilh Zeibch J'tdlrodiun, 1<)2J 27 287 
"JnsolKi thid 1<)I2 18 28! Ztitufi atwnj Chun IOJ2 78 11 

7 He 11 wig Auhcli aiiorg Chun L ( K)0 25 JS5 Builulot Gompl rind, 1880, 91, 
1024 (ompaicKiym J Ru^ P/M/S Chan >Soc 1 ( JO ( ) 41 382 

8 llncl /jdluh anorg Chcm , 1 ( K)0 24 J2 

}) StcgCL /juttch physical Ghcm 100 i 43 505 

10 Mush indllhymis Trim* Chun tioc 1913 103 781 

11 Biltz and btollcnwcik Zidl^k anonj Cficm 1920 114 174 

1 Hartung, Trans Chew /S y oc , 1922 121, 682 compare Koch and Schiadei, Zeiisch 
Phynk, 1921, 6 127 

13 Wachter, J prakt Chem , 1843, 30, 330 



320 OXYGEN WITH AZOTE 

insinuate that the results in the above table 
are derived from inaccurate experiments In 
the course of my investigations, I have had to 
repeat the experiments of many , but have 
found no results to which my own in general 
approximated so nearly as to those of Mr 
Davy in his Researches As knowledge ad- 
vances, however, greater precision is attainable 
from the same facts As for Mr Cavendish's 
important experiments, they were intended to 
shew what elements constitute nitric acid, ra- 
ther than the proportion of them , and they 
were made at too early a period of pneumatic 
chemistry to obtain precision 

The first line of the table contains the pro- 
portions of azote and oxygen in nitrous gas, as 
determined by the combustion of pyrophorus 
Mr Davy justly considers this as least entitled 
to confidence The second and third v\ere 
obtained from the combustion of charcoal in 
nitrous gas The second is grounded upon 
the ox) gen found in the carbonic acid By 
making tht calculation ot this from more re- 
cently determined proportions of charcoal and 
oxygen, I reduce the azote to 5 4 1 he third 
is derived from the azote left after combustion 
Mr Da\y finds 15 4- measures of nitrous gds 
yield 7 4 of azote , or 100 measures of nitrous 
gas yield 48 measures of azotic g is 



SILVER 311 

formula Ag 4 1 It is also said to be produced by reduction of silver 
monoxide by hydrogen at 38 C , 2 and by other methods 3 

Silver monoxide, Ag 2 Addition of the hydroxide of barium or of 
an alkali-metal to silver nitrate solution precipitates the monoxide as 
a blackish, amorphous powder, which crystallizes from ammomacal 
solution in violet crystals Its density is given as 7 143 and 7 250 
Ammomacal silver oxide has been known to explode, the phenomenon 
being probably due to the formation of "fulminating silver" (compare 
p 315) 4 

The monoxide is decomposed by heat into silver and oxygen, the 
liberated metal playing the part of an autocatalyst in accelerating the 
reaction 6 Finely divided platinum and manganese dioxide also cause 
acceleration of the transformation It is decomposed by the action of 
light, with evolution of oxygen, and possibly formation of silver sub- 
oxide 

Silver monoxide dissolves in water, forming an alkaline solution 
which turns red litmus blue At 25 C its solubility corresponds with 
2 16xlO~ 4 gram-molecule per litre of water, 6 and at 15 C Rebiere 7 
found the same value It is a strong base, its salts having a neutral 
reaction The solution is coloured reddish and decomposed by the 
action of light, the change being possibly attended by deposition of the 
suboxide or of colloidal silver 

Its heat of formation is about 6 4 Cal 8 It decomposes hydrogen 
peroxide, with liberation of metallic silver 9 With carbon tetrachlonde 
it reacts at 250 C in accordance with the equation 10 

Ag 2 0+CCl 4 =2AgCl+COCl 2 

In the moist condition it finds extensive application in organic chemistry 
to the replacement of halogen by hydroxyl u It can act as a reducer 12 
Argentic oxide, AgO A hot alkaline solution of potassium per- 
manganate partially oxidizes silver monoxide to argentic oxide 13 

Ag 2 + 2KMuO 4 +2NaOII=2AgO+K 2 MnO 4 +Na 2 MnO 4 +H 2 O 

The reaction is icversiblc This oxide is said to be formed by anodic 
oxidation of silvci m alk ilme solution 14 It is a weaker base than the 
monoxide, but its solution m eoncentr ited nitric icid contains Ag(NO 3 ) 2 
Barbien regaids it is belonging to the class of ozomdes, and differing 

1 (jiunt/ ( omftl nnd 1801 112 HOI 
( lase i finish (ntoni Cluni I ( MH 36 ( ) 

3 Wohlu Annnlui 1857 101 iOJ 1800 114 119 Rose Pogrj lumilin 1852 
85 $04 MuUuninn Btt 1887 20 983 von clcr Pfoicllcn ibid 1407 Lcduc ind 
Labiouste ( 1 otnf)t raid l ( )()7 145 55 

4 Milignon Bull Aoc r/w/w 1908 J4] 3 018 

5 Lewis /jnlvh i>hy\ilal ( 1 htm l<)0 r > 52 310 
tt Noyts ind Kolu ibid I<)05 42 $*(> 

7 Hcbicu Hull Nor thim 1 ( )I5 |4| 17 J0 ( ) 

8 lewis /jnt^ch phi/nlal Ctum 1 ( )0<> 55 44 ( ) Lompai< Ihomsen Thunio<Jutni<>tty 
(Longmans 1008) 284 I'tithtlot Compt rend 1878 87 575 067 Ann Clum Pkys 
1878 [5] 15 180 

8 (omj>ai( von Booyii timl VilliRcr Jkr 1 ( )01 34 740 2709 

10 Michael and Mmphy lm<r Chun / l ( )l() 44 $05 

11 Compiro M id sen finish anon/ (%(m 1912 79 1^5 

12 Chanelrasena and higold Tram. Gkem Hoc 1922, 121, 1552 

13 Birbuii Alii li A(cad Lincci L907 [5J 16 n 72 

14 Luthei andPokom^ Ztttuh anory Chcm 1908,57,290 compare Boboiovsky and 
Kuzma, ZaUch Elckhochem 1908, 14, 190 



322 OXYGEN 1 WITH \ZOTE 

great importance It not only shews the con- 
stitution of nitrous gas, but that of nitric acid 
also It appears, that by electrification ex- 
actly one half of the azotic gas is liberated , 
and its oxygen joins to the othei half to form 
nitric acid The immediate effect of the 
electric shock is to separate the atoms of azote 
and oxygen, which by their junction form 
nitrous gas , the moment the oxygen is libe- 
rated, it is seized by another atom of nitrous 
gas, and the two united form an atom of 
nitric acid which escapes into the water In 
other words, 100 measures of nitrous gas con- 
tain 48 of azote , by electrification, 24 mea- 
sures of azote are liberated, and the other 2 1 
measures acquire the oxygen lost by the for- 
mer, and become nitric acid, which arc ab- 
sorbed by the water 

A repetition of Mr Cavendish's experiments 
\\ill be found to confirm the above conclusion 
I have in three or four instances undertaken 
experiments of the same nature, and with like 
results , but as these are of a laborious kind, 
it is not so convenient to execute them One 
of these was more particularly an object of at- 
tention, and I shall relate it in the detail A 
quantity of pure o\)genous gas was diluted 
with common air by degrees till the mixture 
contained 2<) measures oer cent of azote, thai 



SILVER 313 

spending with 1 2 x 10~ 16 gram atom of silver per litre * When heated 
with silver sulphate at 300 C , both salts are reduced to metallic silver 2 
In the fused state it is miscible with molten silver in all proportions 
When heated in vacuum, it decomposes into its elements rapidlv at 
810 C 3 

The interaction of silver sulphide and mercury is considered on 
p 290, and that with cyanides on p 292 

Silver sulphite, Ag 2 SO 3 The sulphite is prepared by precipitating 
silver nitrate with the theoretical proportion of sulphurous acid or 
sodium sulphite, the salt being decomposed by excess of the acid, and 
dissolved by excess of the sulphite It is a white substance, its colour 
changing under the influence of light to purple and then to black Its 
solubility 4 in water is less than 1 20000 When boiled with water, it 
decomposes in accordance with the equation 

2Ag 2 S0 8 =Ag 2 SO 4 +2Ag+S0 2 

When heated alone, 10 per cent decomposes as indicated, and the 
remainder is converted into silver dithionate and metallic silver 6 

2Ag 2 S0 3 =Ag 2 S 2 6 +2Ag 

Several complex sulphites of silver with sodium and ammonium have 
been described 6 

Silver sulphate, Ag 2 S0 4 The sulphate is produced by dissolving 
the metal in sulphuric acid, and by the action of this acid on the nitrate 7 
It forms white, rhombic crystals, isomorphous with those of the corre 
spending sodium salt, and melting at low red heat Its density is 5 45 8 
The solubility of silver sulphate in water at various temperatures has 
been only paitially investigated At 14 5 C , 100 grams of saturated 
solution contain 730 gram of silver sulphate 9 , at 25 C the solubility 
is 0267 giam-molccule per litre of water 10 Its heat oi ioimation from 
the metal, oxygen, and sulphur dioxide is 96 20 Cal n 

When the sulphate is heated to iusion in a eunent ol hydiogcn 
chlonde, it is eonveited completely into chloride 12 

Ag 2 SO 4 +2HCl=2Agll+II a SO 4 

lie itm<r with silvei sulphide e xusc s partial i eduction to metallic silver 13 



Mom Llic solution in dilute sulphmie add tlnee acid sa//6 have been 
obtained AgllbO 4 , pale yellow pusms , 2Ag 2 O,5bO 3 ,51I 2 O, lustious 



1 Ixxll uid( r ind 1 IK is /iLitech anoiy Chem , 1904 41 192 

buUm llu 1908 41 JJ r ><> 
' Dimin ind Mu/ Itn 1<)07 40 477f> 
4 Kaubitfny Com pi i<utl 1909 149 8 r )8 

lUubitfny ibid 1 J r > 858 

' tSv< iissnn tto 1871 4 713 llosi nhcmi and Stoiulia-ust i /a^s<// anotg Chem , 
1900 25 72 

7 (onipjM Mis Bull \cm\ roy fidt/ J8(>() [2| 9 J22 

8 UK h u<ls ind I OIKS /idluh anoni Cluni 1907 55 72 
> Bat re Ann Chim Ph\^ 1911 [J 24 145 

10 Rothmund Juts<h ptiy>ikal Chem 1909 69 52 } 

11 Lhumscn Thermochemistry (Longmans 1908) 323 

12 Richaids and Jones loc cit 

1J Sackui Abegg and Auerbach s Handbuch der anorg Chem , Loipsic 1908, 2, i , 714 



324 OX\GN WITH AZOTE 

experiments The first line shews the results 
derived from the combustion of hydrogen in 
nitrous oxide From several experiments, 
Mr Davy selects one in which 59 measures of 
nitrous oxide and 40 of hydrogen were fired 
together, and seemed just to saturate each 
other, leaving a residuum of 41 azote , but 
this residuum must have contained a few atoms 
of azote originally mixed with the oxide and 
the hydrogen, and may therefore be supposed 
to be overrated If we suppose S9 oxide to 
contain 40 azote, it will reduce the \\ eight of 
an atom of azote from 6 1 to 5 6 In my own 
experience, equal volumes of nitrous oxide 
and hydrogen, saturate each other, and the 
volume of azote left is equal to one of the 
other two, making the due allowance for im- 
purities This would imply that a measure of 
azote + half a measure of oxygen, should, 
when combined, constitute a measure of ni- 
trous oxide , but the united weights are about 
5 per cent too little, according to the specific 
gravity of the oxide given above 1 appre- 
hend the oxygen this way is underrated, owing 
perhaps to the formation of an unperceiv^d 
quantity of nitric acid In the second line, 
we have the proportions of azote and oxygen 
in nitrous oxide, derived from the combustion 
of both phosphuretted hydrogen and charcoal 



SILVER * ^ 315 

and is exploded energetically by percussion or by exposure to green 
light It is suitable for use as a general primer x 

Berthollet's " fulminating silver " is produced by addition of alcohol 
to a concentrated solution of silver monoxide in ammonium hydroxide 
It forms small, black crystals, exploded by friction, and soluble in 
potassium-cyanide solution It probably has the formula NAg 3 or 
NAgH 2 , 2 and it has no connexion with silver fulminate, C N O Ag 

Silver hypomtrite, Ag 2 N 2 O 2 Addition of silver nitrate to solutions 
of alkali-metal hypomtrites produces the hypomtnte as a yellowish 
precipitate It is very slightly soluble in water, is sensitive to light 
and is decomposed by heat into silver, nitrogen oxides, and 
nitrogen 3 

Silver nitrite, AgNO 2 Sodium nitrite 4 and the corresponding salts 
of potassium and barium react with silver nitrate to form silver nitrite 
It crystallizes in long, greenish yellow, rhombic needles, the density at 
C being 4 542, and between 21 and 31 C 4 453 5 At 15 C its 
percentage-solubility is 2752, 6 and at 18 C 0216 gram-molecules 
dissolve m 1 litre of water 7 

In the moist condition the salt is readily reduced by organic matter 8 
When heated rapidly in vacuo, it is completely decomposed into silver 
and nitrogen peroxide Slower heating in air causes side reactions in 
accordance with the equations 9 

Ag+2N0 2 =AgN0 3 +NO , 
AgN0 2 +N0 2 =AgN0 3 +NO 

Scvcial double salts with alkali-metal nitrites have been described 10 
Double compounds with ammonia of the formula, AgNO 2 ,NH 3 , 
AgNO 2 2NII 3 , and AgNO 2 3NH 3 have also been prcpaicd n A double 
salt with cjLSium, AgCs(NO 2 ) 2 , is formed by the interaction of cjcsmm 
nitrite and silver nitrite It crystallizes in lemon yellow needles 12 

Silver nitrate, AgNO 3 Silver, silver monoxide, silver sulphide, and 
silvei eaibonate dissolve m nitric acid Concentration of the solutions 
yields eolourless, ihombic erystals of silver nitrate, of melting-point 
20b C , ind density 4 3554 It is characterized by its eaustic aetion 
on the skin, its power ol blackening it, its antiseptic pioperties, and its 
metallic taste 



I Wohlci and Mallei /uJscA J/LA Afc/tiCbi and tiprcwj btoffwctai 1907 2 181, 203 
244, 2(> r ) 

Itisdnir Annalin IhS(> 233 9J oompuc bicvcils '/iLit^h aiif/cw CliLm 190U 

2.2, () 

J Kiiscluui /j<Uvli ationj Chcm IS ( )8, 16 424 Haul/sell and Kaufinxnn Aitnalen 
18% 292 i!7 l)iv(is 7Ws rinm /SV>f 18<)<) 75 108 Ptoc ('tutu /Sot 1 ( )07 23 
2(>(> An^( li ind M ut IK tii Mil It \(iutl J uutt l ( )0b [ r >| 17 1 ^5 R xy uid Gaiiguh 
Txni\ ( hon S/w 1<)07 99 1402 

4 Oswild Inn ClHHi /V/ys 1 ( )I4 |<)| I J2 

r 1 iy /M///S Chun Mot 1 ( )()S 93 ( ) ( )7 

6 ( i< Dillon ind Wud / Annt Chtw /S'w 1915 37 2JU 

7 AUgg uid I'uk Uir 1905 38 2571 Zttkch MeUrockuu , 1900 12 592 Ztthch 
anor</ Cfu m 1 ( )05 51 1 

8 Oswild Lot at 

Oswild Compl nnd 1011 152 ibl compare Abcgg and Tick Bu 1905,38 2571 
Zci^ch J J L( I ti o( IK m 1<)00 12 r > ( )2 /aisr/t awry Chcm , 1900 51,! 
10 luschti Po(/(/ Anruiltn 1878 74 120 

II lUychlcr Bcr 1883 16 2425 

12 Jamieson, Arner Chem J , 1907, 38, 014 



326 OK1GEN WITH AZOTE 

weight otaii atom of azote v\ill be according!) 
found = 5 25 

It is lemarkable, thit in the combustion of 
hydrogen m nitrous o\ide, the oxygen (as esti- 
mated by the loss ot hydrogen) is usually found 
below par , and it is the same with the azote 
in the combustion of olefiant gas, as Mr Davy 
has remarked , I have found it so likewise 
with carburetted hydrogen or coal gas I ap- 
prehend when azote disappears, it is fiom the 
formation of ammonia 

Besides the three compounds of azote and 
oxygen already considered, there are at least 
two more One is called nitrous acid , it is a 
compound of nitric acid and nitrous gas The 
other I call ox> nitric acid 5 it is a compound 
of nitric acid and oxygen Priestley disco- 
vered the fact that nitric acid absorbs nitrous 
gas very large! v, and theieby becomes more 
volatile He fou id that 1^0 ounce measures 
of nitrous ^as over water disappeared in a day 
or two, when a phial containing <)(> water 
gram measures of strong nitric acid v as in- 
closed with the gas Ihe colour ot the acid 
as it ab&oibb nitrous gab is griduilly chuged 
from pale yellow to oungc, gieui, and iin ill) 
blue green Mr Davy has Ubcd his endeavour* 
to find the quantity of nitrotb gab which nun' 



SILVER 317 

Arsme 1 reacts with a concentrated solution of silver nitrate, pre- 
cipitating yellow Ag 3 As,3AgN0 3 , decomposed by water with liberation 
of metallic silver With dilute silver nitrate the reaction occurs m two 
stages 

AsH 3 +3AgN0 3 =Ag 3 As+3HNO 3 , 
Ag 3 As+3AgN0 3 +3H 2 0=H 3 AsO 3 +6Ag+3HNO 3 

In presence of dilute ammonium hydroxide reduction to metallic silver 
takes place in three stages, ammonium arsenate and nitrate being 
simultaneously formed 

AsH 3 Hr3(AgNH 3 )N0 3 =Ag 3 As+3NH 4 N0 3 , 
Ag 3 As+3(AgNH 3 )NO 3 +NH 4 OH+H 2 =NH 4 AsO 2 +6Ag+3NH 4 NO 3 , 

NH 4 AsO 2 +2(AgNH 3 )NO 3 +2NH 4 OH=(NH 4 ) 3 As0 4 +2Ag+2NH 4 N0 3 

The action of stibine 2 is similar to that of arsme, but only about 
2 per cent of the antimomous acid formed dissolves, the rest remaining 
in the precipitate 

SbH 3 +3AgN0 3 =Ag 3 Sb+3HN0 3 , 
Ag 3 Sb+3AgN0 3 +3H 2 0=H 3 Sb0 3 +6Ag+3HN0 3 

Excess of silver nitrate reacts with iodine in accordance with the 
equation 

6 AgNO 3 + 61 + 3H 2 = AgIO 3 + 5 Agl + 6HNO 3 

When the iodine is in excess, the reaction is represented by the equation 
5AgN0 3 +6l+3H 2 0=HIO 3 +5AgI+5HN0 3 

The second reaction is applicable to lodometry, the titration of alkali 
metal hydroxides, and the titration of silver nitrate 3 

With mercury a solution of silver nitrate yields various amalgams 
and crystalline double compounds of silver and mercury 4 

Silver mtiatc ioims double salts with the hahdes, cyanide, and 
thiocymitc ol silvci 5 It also yields with silver sulphide a compound 
outlining cqmmolccul ir proportions ot the two salts, picparcd as a 
ydlowish-<ri( en puupititc by the letion of hydrogen sulphide on a 
conuntiitcd solution ol silvei nitrite It forms other double salts 
with the niti itcs ol lithium ind sodium, 6 potassium, 7 ammonium, 8 and 
th ilhum r liu solution ol silvci nitiate in immonium hydroxide yields 
rhombic pnsms, A^NOj/JNIIj, isoiuorphous with silvei mtiate 10 



1 KtcUU h(n 1 of kern inn .indl'ckudt ZpiMi anal Chew 1907 46 071 Reckleben 
uid I otl < in uin ibid 1008 47 I2(> 
Rc( I Idxn ttir 1000 42 I4 r >8 

J Piwloll indhthciM / /iwss 1 ky* C/HHI hoc l ( )07 39 043 

Mompin Kdiidds /,u,hth pln/u] al ( 1 hun J002 42 22 r ) ]<)()<> 54 G07 , Og^, 
ihid I SOS 27 JS r > 

Hcllwi^, /dl^(h anon/ Chun 1900 25 18J 1 ugci Zcituh Kry^t Mm 1007 
44 100 Sc iipii AlU Jt Aad Jincti 101J | r >J 22 11 4^2 
( Ihssink /<tlx/i plnjulal Chcm 1000 32 r >43 

7 Ritv^ ibid l^^ ( > 4 008 Sihiuw makus ibid 1000 65 553 Schrememakcis 
ind do LUai Chtm Wtekblad 1910 7 259 

8 bcliumcmakcis loc ut bchrdnunakc is and dc Baat, loc cil 
van Pyck, l>roc K AJ ad Wehnrth Anntudam 1900 2 543 

10 Ji(ycbicr J CUim phy*> 100J I 345 compaic Casstoio Qazzetta 1907 37 i 
310 Hantzsoh, Zeitech anorg Clie.ni , 1899 19 104 



328 OXVGEK WITH A20TE 

ceased, which will be half a minute, the resi- 
duary gas te transferred into another tube, it 
will be found that 1 measure of oxygen and 1 8 
of nitrous gas have d'sappeaied , the mixture 
ts to be made over water 

2 When 4 measures of oxygen are put to 
1 3 of nitrous gas in a tube two tenths of an 
mch in diameter, and 10 inches long, s>o as to 
fill it , it will be found that 1 measure of oxy- 
gen will combine with 1 3 of nitrous gas, m4 
or 5 minutes 

3 When I measure of oxygen and 5 of ni- 
trous gas are mixed together, so as to form a 
thin stratum of air, not more than ^-th of an 
inch in depth (as in a common tumbltr) , it 
will be found that the oxygen will take from 
3 to 3f measures of nitious gas in a moment, 
and without an) agitation If equal measures 
are mixed, then 1 oxygen takes about 2 2 
nitrous 

4 When water has been made to imbibe a 
given portion of oxygenous gas, and is after* 
wards agitated in nitrous gas, the quantity of 
nitrous gas absorbed will always be more than 
exhausted water would take, by a quantity 
equal to 3 4 or 3 6 times the bulk of the oxy- 
genous gas And, vice versa, when water 
has imbibed a portion ot nitrous gas, and is 

tlipn aonf-afpH with rwvcrpnrmc crac f-h* nuantitv 



SILVER 319 

in solid solution Addition of silver arsenate to an aqueous solution of 
arsenic acid precipitates a white, crystalline compound, Ag 2 O,2As 2 5 , 
decomposed by water into silver arsenate and arsenic acid 1 

Silver carbide, Ag 2 C 2 Excess of an aqueous solution of acetylene 
precipitates from ammomacal silver nitrate the greyish-yellow carbide 
On exposure to light it darkens rapidly When heated, the dry salt 
explodes With hydrochloric acid it evolves acetylene, and with nitric 
acid it undergoes complete decomposition Water causes hydrolysis 
to some extent, with production of silver monoxide Agitation with 
sodium-chloride solution causes similar hydrolysis, the solution becoming 
strongly alkaline 2 The heat of formation from the elements is given 
by Berthelot as 87 15 Cal It forms a series of double salts with the 
hahdes, sulphate, and nitrate of silver 3 

Silver carbonate, Ag 2 C0 3 When the equivalent proportion of 
potassium carbonate or potassium hydrogen carbonate is added to a 
solution of silver nitrate, silver carbonate is precipitated as a yellow 
powder Addition of excess of potassium carbonate causes simultaneous 
precipitation of a proportion of silver monoxide Pure silver carbonate 
is white, but is sensitive to light At 200 C it decomposes with 
evolution of carbon dioxide 4 Its heat of formation is 120 8 Cal 5 
Silver nitrate precipitates from a hot, concentrated solution of potassium 
carbonate a double salt of the formula Ag 2 C0 3 ,K 2 C0 3 A crystalline 
double compound with ammonia of the formula Ag 2 C0 3 ,4NH 3 ,H 2 O 
is produced by the spontaneous evaporation m air of an ammomacal 
solution of silver oxide Under the influence of sunlight the crystals 
become black , and on exposure to air they lose water and ammonia, 
yielding silver e irbon itc 6 

Silver cyanide, AgC N A white, amorphous precipitate of the 
cyanide is obt um (1 by intc Fiction of i silvc i salt ind a cyanide in aqueous 
solution It (iyst ilh/es iiom i hot concentrated solution of potassium 
carbonate in (me needles It is unxffeetecl by light, but heat eliminates 
one hilf <>1 the e y ino^e n with production of silver " piracyanido " 7 
Uoth hyelioe hlone K lei inel meieime ehlonele eonveit it into silver 
chloride \\ith hy<hojr<n sulphide \( yie Ids silver sulphide , ind hoiting 
with sulphm h msloimsil mlosilxei llnoeyinile Its he it of form it ion 
iremi silvei m<l < v motr< n is 5 (> ( il 8 r lhen is some evidence ol tho 
e \iste nee olsiKei e\ miel< in t\\o polyme lie ioinis A^CN inel A<r 2 (('N) 2 9 
With hyeli I/UK e } iniele i( lonns eolouile ss e lysl ils, Aj( N,N 2 1I 4 , which 
bl le ke n in < ont u I vvitli in I(l 

Solulion e>l silvei e>i ils ey iniele in pot issmm cyinielc foims potawum 
^ilvet ( i/ft n ult K \<r(( N) , e>ct iheeh il eiyst ils si ible in 111, but blackened 
by light \s 20 C its solubilily is 25 i^r uns pci 100 ufi ims oi witer 11 



K< i 



J< 



it/i^ uid ( uilu i \nnalni IS r ><) in 1()S 

<li^ uicl UsolT /ntvh I< l< I tto< IK m IS<)(> 3 IK) 

up IK INilhdnl ( <nni>l K nd !S<)<) 129 t(>l I oss< n lumtliH lS ( )i 272 

\nid / SM |<)()J [t| 14 Js r > I lunpjon ('/tun N<n^ IS<)J 65 2<) r ) 

lin \nn Chun 7V///s 1H7J | l| 30 2<>0 



Colson ( onti>t nml l ( )0 ( ) 148 S 17 
( Ddvni and Olnur ibid I ( )21 172 1M)2 

7 \{ iinni( Islx i^; / (H/</ \nnnloi 1S4S 73 SO 

8 Bdihdot Ann < 1 hun /V/ys ISSJ [ r >| 29 241 

9 Wugm i \ (th r//s (I nit Naturjurwh Atr-lt 1002 i (>0 

10 li an/en aiul I no! mo; 7nl^c"h minrq Chcni 1011 70 145 

11 Baup Ami Chim ]>hyi 1858 [3] 53 4G4 



330 OX1GEN WITH \ZQTL 



w i 1 f Ji to circumstances ta^cs any mtei- 
mediate portion ? Are there indefinite grada- 
tions in the compound ? I cannot conceive 
this , neither do the racts at all require it All 
the pioducts that need be admitted to explain 
the facts are three It has been shewn thai 
1 measure of oxygen requires 1 8 ot nitrous 
gas to form nitric acid, according to the results 
derived from the electrification of nitrous gas 4 
and the conclusion is corroborated by other 
facts It appears from the above obseivations 
3 and 4, that oxygen is found sometimes to 
combine with 3 6 times its bulk of nitrous gas, 
md that this is the maximum , but it is just 
twice the quantity requisite to form nitric 
acid itiseudent, therefore, that a compound 
is formed in which tnere are twice as many 
atoms of nitrous gas as are necessary to foim 
nitric acid 7 his then may he called mfiou\ 
acid , and the elementary atoms consist ol l 
ot oxygen and 2 of nitious gis, united by che- 
mical affinity If the otner extreme, or the 
minimum quantity of nitrous gas to which oxy- 
gen had united, had been 0, or h-H what is 
iound in nitric acid, then this v ould have 
shewn the union of 2 atoms of oxygen with 3 
of nitrous gas, and the compound miqht be 
called orymtnc acid Now, though it does 

innear that we are able as \et to form 



SILVER 321 

The relative insolubility of some of the salts of silver is in the order 
chloride, cyanide, thiocyanate, bromide, iodide, and sulphide The metal 
is usually estimated gravimetrically as chloride, or by electrolytic deposi- 
tion It can also be weighed as chromate x Other gravimetric methods 
are reduction to metal by hypophosphorous acid, 2 and by alkaline 
glycerol and other reagents 3 

Volumetric estimation * in neutral solution can be effected by titra- 
tion with standard sodium chloride, potassium chromate being employed 
as indicator , and in nitric-acid solution with ttuocyanate, using ferric 
alum as indicator, or with sodium chloride without any external 
indicator 

1 Goooh and Bosworth, Zeitsch anorg Ohem , 1909, 62, 69, 74 

2 Mawrow and Hollow, ibid , 1909, 61, 96 

3 Whitby, ibid , 1910, 67 02 

4 Compare also Gooch and Bosworth, loc cit 



VOL II 21 



332 OXYGEN WITH AZOTE 



i Nitrous Gas 

Nitrous gas is formed by pouring diluie 
mtnc acid upon many of the metals , it should 
be received over water The best mode of 
procuring it is to put a few small pieces or 
filings of copper into a gas bottle* and pom 
nitric acid of the specific gravity 1 2 or I 3 on 
to them j the gas comes over in a state of purity 
(except so far as it ib diluted with atmospheric 
air) and without the application of heat The 
common explanation of this process is, that a 
part of the nitric acid is decomposed into the 
elements nitrous gas and oxygen , its oxy- 
gen unites to the metal to form an oxide, 
which the rest of the acid dissolves Upon a 
more particular examination of the phenomena, 
I find, that estimating the quantity of real 
acid by Kir^n's table, Jf. part ot the acid is 
decomposed to furnish oxygen to the metal, 
and to yield uurous gas, T unites to tue me- 
tallic cmde, ctncl the i< tnamng 4 seizes the 
nitious gas, ind ronns nitrous acid, but in the 
degree of condensation of" the acid, it is unable 
to hold more than ^ or ~ of it, and the rest ss 
therefore evolved For example, 200 gram 
measures of nitric acid of 1 32 strength, di- 
luted with 100 water, dissolved 50 grams of 



GOLD 323 

Norway The cyanide-process has been highly developed in South 
Africa, and the electrolytic separation from copper in America 

History Gold has been esteemed a precious metal from prehistoric 
times The high value placed on it is indicated by the writings of Homer 
and of Biblical authors The locality of the ancient sources of supply 
is now a matter of doubt, but there appear to have been extensive 
deposits, now probably worked out 

In the code of Mcncs, who was King of Egypt about 3600 B c , the 
ratio in value between gold and silver is given as 1 part of gold to 2 5 
parts of silver Corresponding with the period about 2500 B c there are 
extant Egyptian lock carvings illustrating the washing of auriferous 
sands and the subsequent smelting The sands were washed ovei 
smooth, sloping rocks by running watci , and the gold was caught in the 
hair of raw hides spread on rocks The " Legend of the Golden Fleece " 
probably originated m the use of sheepskins foi this purpose It 
narrates the story of a piratical expedition made about 1200 B c with 
the object of stealing gold obtained from rivers by the aid of sheep or 
goat skins in "the region now tcimcel Aimcma 

Chikashige * found gold associated with other metals m a Buddhist 
statue of the third eentuiy A D , and also in a Core an bronze minor of 
the tenth century A D 

The woiel " gold " is piobably elenveel from the Sanskrit Jvahta, 
from Tval, me in ing to shine 2 

Golel coins weie lust m ide m the Western woild about 700 B c The 
paiting ol i>olel inel siKei \\ is then pi ictisecl, ancient Greek coins 
cont lining 097 to f ) ( ) cS pel cent ol #ohl The pioecss was one of 
cemcntition At Hitei ptiuxl puling wis leeomphsheel by me ins of 
mtiic Kiel At UK ]>i(S( nl him lh< |> ntmgoJ gold Jiomsilvci is cflcctcd 
by chloime in Aush tin !>N <lholysis in Anuiie i, ind by sulphuiic 
uid in KIIIOJH * 

Fxti action 4 Then IK lorn in un pme esse s of gold ( \h ution 

1 Mi ( h mie il piex e ss< s leu pie p 11 mo ind w ishing 1 he e>ie 

2 Pi())iiihon ol I IK e>ies \vilh smmllimous 01 subsequent 
un ilg un il ion 

$ ( IK nn< tl ( \h i< I ion j)io( ( ss< s 
1 Sm< II m^ ol ( ( 1 1 un 01 < s 

( 1 ) \\ \SllliM Pi <)( I SSI S 

(old ( mix ( \l i K (< (I h\ \\ ishmt onl\ \\ h< n il is pi< s< nl is me i il in 
llu loiin ol |)iid(l(s \\liK h n< nol loo iniiiuh I In \v ishmo Kinoxes 
the sj)ih( ill\ liolihi puls ol lh< milunl UK IK me i i^olel puheles 
sinking le> I IK holloni 1 he j)ioss is i|>|>h< il)l( (Intelly to ie>l(l 
h( biinn s UK! UK! lo <M>1<1 Ix niun locks illei eiuslinio 1 IK e nishing 
is ell((l(d l>\ sloiK (insheis lollnio nulls inel si imp nulls 1 he 
\v ishmt is c u i K (I oul ( il IK i l>\ snh|( ( hug I IK mile n il lo I he piolonged 

1 ( hil islu^ /;//// < li in S/u I ( )JO 117 <)I7 

(<mi|)ii< I <.s< U<l<ilhu<w <>l < <>hl ()llil (( iillni l ( )l r >) 2 

Monipin Si i I Knl< I i si s Pn snl nti il A<l<ln MS i<> lh< rnsliliitt of Mining md 
MdallurL^y MitdilS l<)| r > \//////f l ( )l r > 95 KM) 

1 hoi lull m<tilliii_i< il (l<1 ills t(f(i(H(( nhoiild IK m ul< lo I In MttnHnitm of Oold 
by Sn I Kiili 1 os( (( n(liii) uid 'I In \<ti i>li >i<i (unl lss//;/o/ l*nn<ni\ Mdah by J H A 
fcimith ((.nllin) 



334- OXYGEN WITH AZOTE 

stantly fatal It extinguishes combustion in 
general , but pyrophorus spontaneously takes 
fire m it , and phosphorus and charcoal in an 
ignited state burn in it, and produce a decom- 
position Pure water, (that is, water free from 
all air) I find, absorbs about -^th of its bulk 
of nitrous gas, but only ^ T tb of it can be ex- 
pelled again by other gases it should seem, 
then, that a small portion of the gas actually 
combines With the water, while the greater 
part ib, like most other gases, mechanically 
retained by external pres$ure 

Nitrous gas, as has been observed, is decom- 
posed by ^Icctncity one half of the azote is 
liberated, and the other half unites with the 
evolved oxjgen, and forms nitric acid Ac- 
cording to Davy's analysis by charcoal, nitrous 
gas is constituted of 2 2 azote, and 3 oxygen 
by weight , or 42 azote, and 58 oxygen per 
cent nearly , which i* the same as I obtain 
by electricity and other means If completely 
decomposed, 100 measures would be expanded 
to 104- 6, of which 48 would be azote, and 
56 6 oxygen 

Dr Henry ] ias recently discovered that ni- 
trous gas is decomposed by ammoniacal gas , 
the two gases are mixed over mercury m 
Volta's eudiometer, and an electric spark is 
found sufficient to explode them Vv hen an 



GOLD 325 

alkali The residue is extracted with 35 per cent solution of potassium 
cyanide, then with 08 per cent solution, and ultimately with water 
The extract is transferred to tanks, and the gold precipitated as a powder 
by addition of zinc It is then washed out from the bottom of the tanks, 
dried, and freed from zinc by roasting and fusing 

In the electrolytic precipitation of the gold an iron anode and a 
sheet-lead cathode are employed, the current density being very low, 
about 5 amp per sq metre * The gold is deposited on the lead, and 
after removal of this metal still contains a considerable proportion of 
both lead and silver It is freed from them by the operation called 
" parting " 

Access of an is essential to solution of gold in potassium cyanide, 2 
the process being attended by evolution of hydrogen Lead, bismuth, 
antimony, cadmium, silver, and mercury also dissolve in presence of 
air , but copper, iron, aluminium, nickel, cobalt, and zinc dissolve in 
absence of air Gold and silver are distinguished by the fact that 
their maximum solubility corresponds with a very low concentration 
of the potassium-cyanide solution, a phenomenon probably due to the 
slight solubility of air in concentrated solutions of this salt 3 The 
solution of gold in the cyanide solution is accompanied by the inter- 
mediate formation of hydrogen peroxide, and the process is aoceleiated 
by addition of this substance 4 

2Au+lKCN+2lI 2 0+0 2 =2KAu(CN) a +2KOH+H 2 2 , 
2\u | 1KCN-I II 2 2 =2KAu(CN) a +2KOII 

A similai iccclci ilm# clfcefc is excited by othei subst mccs, such as 
pot issium lerncy nude, potassium permangan itc, potassium chromate, 5 
sodium pcioxule, 6 buium peioxult, 7 cyinogen bromult, 8 (\ no_ n 
chloiuk, 9 pt isulph itt s uul cciiun 01% uuc compounds 10 The best 
method ol tcdiumi? ilu piopoiliou oJ the othei metils is to maintain 
thecyuudt solution dilute 

In pica pit itni^ Ilu #old by /uu, ilu piopoition reqtmed is about 
seven tinu s t h it intlu it < tl by tht c qu itiou 

Zn | 2Au 2Au | Zn , 

the (list K p UK y IK injj du< to solution ol p ut ol Hit /me uitlu (yuudc 
solution wit h ( \ olut ion ol h\dmjr< n ll 1'mily ol the /nit is in unpoil int 
i K lot in ( ount< i u (m<r ( his loss 

In t IK ( l< < tiol\ IK d< position ol i^old liom ( y inidt solutions hydio^t n 
ishbuihd it UK ( ilhodt ind intquiviluil nuinbt i ol liydio\yl ions 
<r\V( uptli(ii <liii<s il UK mod( llu solui ion dt vt loping in ilkilinc 
ic u lion ( > inojji \\ ions ilso^nt up I lit n thills li llu inodt , IK ing 

1 SM tut us /M/sr// I'ldlKx/inn IH ( ) r > 2 r >J2 

Wills m<l \Vlii|)j)l( //f///s \nin Hntindnm So< l<)17 32 J r >7 
1 Muliuuii < hnn \ ni s I SM { 67 l ( )l IS<)> 71 7J 
1 I odl nidi i / il^lt itinj u ( IK in IS<)(> 19 >S J 



Mnl 
' Moi 

7 S || 

8 Sul 



l< nliuii i ttn IS<){ 26 il() 
HIK IK / Sor ( linn I ml IS<) \ 12 7<>7 
I/ Minimi / IMUJ Mudi I 



i uu ui<l ld CmnttH I nhnl Mo S JJ'IJ Miillioll uid />o// it ml llttltni 

/nl 1S<)() 55 ()(> loins / Srw C/uin I ml IS ( )<) 18 JJU 
9 MoiKns linlidi I'ttlinl No 1SJ7M 

10 Sdidiiu /u/sr// I'lntnxhnn 1H% 2 r >()7 

11 Uslai and Lilwcin Cyanidpro~esi>e zur Goldyewitmung, Hallo 1903 



336 OXYGEN WITH AZOTE 

1 gram of the salt , its specific gravity was 
1 081 , this was agitated with iron filings, to 
reduce any of the red sulphate that might be 
in the solution, which is know n not to ahsorb 
the gas, into green sulphate A eudiometer 
was filled with mercury, except one measure, 
which was filled with the liquid solution , the 
tube was then inverted over mercury, and ni- 
trous gas sent up to the solution, which was 
afterwards agitated It was repeatedly found 
that 1 measure of the solution absorbed 6 mea- 
sures of the gas, and was then saturated Con- 
sequently 1500 gram measures of the solution 
would have taken 9000 grain measures of the 
gas , but 1500 of the solution contained 250 
of salt, of which th was iron, as is well 
known , and 9000 grain measures of the gas 
weigh 12 grains Here, then, 50 grains of 
iron united to 12 grains of nitrous gas Now, 
the weight of an atom of iron is 50 (page 258), 
and that of nitrous jras is 12 It therefore fol- 
lows, that in the < ornbmation of green sul 
phaie of iron with nitrous as, each atom of 



iron unites with an aiom of the g *, L iMv 
to the general lavi of chemical union 

Nitrous gas is still used m cudiometry to 
determine the quantity oi o v ygciicms gdb in 
an) uMxture , and on accoapt of the ca-e <nd 

f\f ifrc -mnliraMnn And the 



GOLD 327 

can be recovered only by a cumbrous process 1 To obviate this difficulty 
the metal, either after parting from silver or in its original state, is 
dissolved, and the gold and platinum precipitated separately 

Parting by aqua regia is effected by dissolving the alloyed gold in 
the acid, silver being converted into its chloride, which is then 
precipitated by dilution with water The platinum dissolves com- 
pletely, and the indium partially, the gold being precipitated by 
addition of ferrous sulphate or chloride With a large proportion of 
silver some of the gold is occluded, and escapes solution in the acid, thus 
necessitating a repetition of the treatment with acid The process lacks 
many of the advantages characteristic of the electrolytic method 

The electrolytic process 2 was introduced m 1863 by Charles Watt at 
Sydney, started m 1878 by Wohlwill at Hamburg, and in 1902 by 
Tuttle at the Philadelphia Mint In the gold chloride method the 
electrolyte is a solution of auric chloride containing free hydrochloric 
acid, the crude metal forming the anode, and pure sheet gold the cathode 
The gold dissolved at the anode is deposited in a pure condition at the 
cathode Other metals arc converted into chlorides at the anode, and 
either i emain dissolved or pass into the anodic slime Silver is con- 
verted into its chloride , this substance partly dissolving, partly depositing 
in the slime, and partly adheimg to the anode With solutions con 
taming more than <3 to 10 pc i cent of hydrochloric acid, and with bullion 
having more than pci cent ol silver, the coating of the anode raises the 
density ol the euricnt and eauses evolution of chlorine 

Rose has Joimd that with in deetrolytc containing 29 per cent of 
free hydroehlout acid uul with a cuircnt density of 5000 amperes per 
squaie metu ol mode suii ut no ehloimc is evolved, even with an 
anode cont lining 20 pet cent ol silver The heavy eurrent causes the 
silvei ehloiide to stp u itt horn UK mode, ind as amous chlonde is not 
allowed to loim dt position ol jirold in Iht mode shmc is prevented 

A solution ol UIIK (hloiide eont unm^ Mo 5 pei cent of gold and a 
cm icnt eltnsitv ol 1000 unpeitspd squ ue metie au usually employed, 
but Rose bis found tin! \\ith i tuiitnt elcnsity oi 5000 ampcies per 
semuemcht in tl<<liol\lt with JO pt i unl oJ gold yields i cohcient 
deposit ( ipiblt of bt mi? K idily u ishcd md in die ible iftei melting 
By this niodilK ilion I lit turn itquutd loi solution ol the anoele is 
lediK t d horn OIK \\< ( k to OIK d ly 

In iddihon to tlu in dlt il>I< intuit ol UK ptodutl obt lined by 
dectioJylK i< fining UK piouss ilso t \h i< Is plitmimi, i tonsil tut nt 
of ne uly dlsmiplisol fiinsvid^old 'Hit United St ties oJ Ainene i 
Mini h is found UK ( let I ml > tit m< thod moit ett)nonnt d th in th it \vitli 
sul])lniiit K itl 

Mi lit i s (In/ fHtttiuft })H><(\\ l in\ol\(s tht K tit)ii of (Iiloiitie on molten 
gold )\< ud \\dli i 1 i\ 1 1 ol boi i\ to pit \< nl spmlmtf r lht i>old is not 
ittuktd but UK silxu is <on\t i It d into ( hlontlt \\htnthtgoldhis 
se>lidititd UK molit n sil\ < i t blonde t olh ( tt tl on UK suiiue is inn off, 
l i sin dl piopoihon ol trold WJien sdvti is the eluel 



1 IMtuil OKI Dintihi s /Wy/M// / IKI7 104 US IMS 

('oniimn \\ohl\ull /tihi/i ll<lho<Ii<ni 1S<)S 4 17<) \2\ Su 1 Knlc P<>s< 
Picsulcntnl Ad<li(ss to tin Inshtuli of Mining and MoUllurgy MuthlS l ( )I r ) \nlut( 
1915 95 100 

J Miller J in<t1t (han IS(>) 106 r >OJ Dttiylu s PolijtiLh J 18d8 188, 251 
1870 197 H 1S7J 205 5*5 187J 208 U2 



3*38 OX1GEN WITH AZOT 

nous proportions, according as one or other is 
in excess Sometimes 3 measures of nitrous 
are saturated with 2 of the acid, and some- 
times wth 4 measures When green sulphate 
of iron is saturated with a kno\\n portion of 
nitrous gas, and the solution is aftei wards agi- 
tated with oxygen, the absorption is somewhat 
slow, (like that with sulphuret of lime) and 
the quantity taken up is equal in bulk to the 
nitrous gas The liquid, from a dark red or 
black, becomes of a bright yellowish red, the 
oxide of iron being changed from the green to 
the red during the process 

It has been made appear, that b) electricity 
one half of the atoms of nitrous gas are decom- 
posed, in order to oxygenize the other half, 
in like manner, in certain cases, one half of 
the atoms of nitrous gas are decomposed to 
azotize the other half This is shewn by the 
experiments of Priestley, but much more ac- 
curately by those of Davy The alkaline sul- 
phites, muriate of tin, and dry sulphures, con- 
vert nitrous gas into nitrous oxide According 
to Davy, 16 cubic inches of nitrous gas were 
converted into 7 8 of nitrous oxide by sulphite 
of potash , that is, 100 measures ga\e 48 75 
he aUo found, that muriate of tin and dr) sul- 
phures changed 100 measures of nitron gas 

bodies have 



GOLD 331 

Cassius as a mixture of colloidal gold and colloidal stannic acid, a 
view practically identical with that of Debray expressed in modern 
phraseology l 

Physical Properties Gold is a metal of characteristic yellow colour 
Its"meltmg-pomt is given as 1035 C , 2 1037 C , 3 1059 3 C , 4 1061 7 C , 6 
1062 4 C , 6 1063 C , 7 3063 9 C , 8 1064 C , 9 1071 C , 10 and 1072 C n 
The most probable value is about 1063 C Capua 12 found that the 
presence of between 6 and 7 per cent of silicon lowers the melting- 
point about 800 C Its boiling-point was determined by Moissan 13 
with the aid of the electric furnace to be about 2530 C , being higher 
than that of copper and lime Its density is given as 19 21, 14 19 2685, 15 
19 28, 16 19 43, 17 that for unpressed gold being 18 884 18 The approximate 
value may be taken as 19 3 The specific heat at low temperatures is 
given as 0297, 19 as 0302 at C , 20 as 0380 at 18 C , 21 and as 0324 22 
and 0316 23 at to 100 C The latent heat of fusion per gram is 0163 
Cal M The hardness on Auerbach's scale is 2 5 to 3 25 Gold is the most 
malleable of the metals, and can be beaten out to leaves 0001 mm 
thick 26 One gram of the metal can be drawn out to a wire 166 metres m 
length Thin layers deposited on glass by heating in vacuo are almost 
colourless in reflected light, but appear of a rose to violet colour by 
transmitted light 27 Neither hydrogen nor nitrogen is absorbed by gold, 
either in the solid or fused state 28 It is a good conductor of both heat 
and electricity 

Chemical Properties The chemical character of the metal accords 
with its low elect loafTmity, an c\ imple bcnii^ its stability towaids the 
action of stion^f u ids , illhough boiling, conecntiated mtiic acid dissolves 

1 Compaii SthiKitlu /nsr// anon/ (Jfuui 1H1H 5 80 (Jiunwild Sjitechsaal 1910 
43 419 

Viollc Ct>iii)tl )<ti<( 1S79 89 702 

3 B(cqu(id ibid 1S()J 57 S r > r > 

4 Diy ind ( l< m< nt \mu / >Su 1 ( )OS | L| 26 tO r > 
ir<y(od uulN<vill< 7;<n/s ('luni bin lS9 r > 67 1021 

( Day uid SoHin in \inn / SM 1910 | 1 1 29 91 

7 (,u<itl<i and Pn ni /iilvli i\ld((ll/ iuid( 1919 n I Dun and l<ook Tratn 

8 Holborii uid Di> ninth s \nnnhii 1901 4 99 
I ( iili( lot ( tni>l n ml IS<)S 126 17 { 

Hull uid ( o(d( /<itvli <in</<n ( IK ni 1911 24 1 l r >9 
HollxiMi ind \\uii \\iul liiiKildi IS<)2 47 107 

( apui \lh /> \tuid I Dim 1920 | >| 29 i 111 

J MOISMUI (oni)>l nn<l 190 141 977 (oni|>m von \V u It nix i^, /u/s(// anon) 
in 1 ( )OS 56 i20 

U/ss \ftfitnidl /A//s lull tin<hvin^<iU 1900 3 2(> ( ) 

Kdilhunn uid I oth /nlvh minx/ ( In in 1901 29 177 

\oijj II iul \tnnilui IS95 49 709 

A\(ili<iT /t il\< h anon/ ( In in I90{ 35 H r > 
8 K ihlhunn uid I oth ibid 1901 29 177 

'M'nhuds nid I i< Uson /nlvlt )th\^\l<tl (linn 1910 70 111 cnmpiu Notd 
imv<r ho Dint plii/^ilal (<\ 100S 6 202 

1 H/ss \hlituidl /////s lull luKlivti^tnll 1900 3 2<>9 

2 Rc^nudt Inn (linn /V/ys ISlO |2| 73 1 
5 \ ioll( ( <ni>t nml 1S7 ( ) 89 702 

1 (oinjun 1 udnif />^/s / aitxhv In S//S/M// M unlnu^ uul hipsu 1901 ll r > 

1 uidolt loinst(in uul M<y<ihol1<i ValnUm tid l U(ilm 1905 r >7 
n ( 1 oinpii< Muspi ill Ilandbmh d<r I tthniuliifr ClmnH IJiunsvviok 1S91 3, 1S29 

7 Houlli vi^m ( oui}>t nnd 1909 149 H(>S 

8 SicvcitB Z,til^k blcltrochun 1910 16 707 



340 OXYGEN WITH AZOTE 

published an essay on the subject in the Journal 
de Physique for 1793, in which the consti- 
tution and properties of the gas were more 
fully investigated In 1800, Mr Davy pub- 
Lshed his Researches, containing a much more 
complete and accurate developement of the 
nature of this gas, than had previously been 
given, as well as of the other compounds of 
azote and oxygen, and several other collateral 
ones 

Nitrous oxide gas may be obtained from a 
salt called mti ate of ammonia, being a com- 
pound of nitric acid, ammonia and water 
The salt is put into a gas bottle, and heat ap- 
plied, which first tuses the salt, about 300, 
by continuing the heat, the fluid salt boils, 
and is decomposed about 400, emitting nitrous 
oxide gas and steam, into which the whole of 
the salt is principally resolved The gas may 
be received either over water or mercury 

Ihe constitution of the salt, nitrate of am- 
monia, according to Davy, is \\hen crystal- 
lized, 18 4 ammonia, and 81 6 acid and wa- 
ter Now, if we suppose an atom of ammonia 
to be constituted of one of azote, 5 1, and one 
of hydrogen,, 1, as will be shewn hereafter 
and that an atom of the nitrate is composed of 
1 atom of each of the elements, ammonia, 
mtnc acid and water (see plate 4, % 36) , 



GOLD 333 

Although derivatives of bivalent gold are known, there is no certainty 
as to the existence of an Au ion 

Applications Alloys of gold with copper, silver, and other metals 
are employed in the manufacture of plate, jewellery, and coins In the 
British coinage the metal is alloyed with copper, the coins containing 
916 6 parts of gold per 1000 This alloy has a lower melting-point than 
gold, and is harder In the United Kingdom there are five legal 
standards for gold wares , 22-carat (containing 22 parts of gold in 24), 
18-carat, 15-carat, 12-carat, and 9 carat 

Gold leaf contains 90 to 98 per cent of gold alloyed with copper and 
silver It is employed in gilding Gold-plating is carried out m a bath 
of potassium auncyanide with a gold anode, the strength being main- 
tained at about 6 85 grams of gold per litre by addition of auric chloride 

The metal finds application in photographic toning as sodium 
aunchlonde The chloride is employed in medicine, and in alloys in 
dentistry " Purple of Cassius " is useful for colouring glass Gold 
lace consists of a silk body with very fine strips of gold twined round 
the silk x 

Atomic Weight In the early years of the nineteenth century the 
subject of the ratio of gold to oxygen in gold oxide was investigated with 
divergent results by several chemists, including Richter, Prout, Ober- 
kampf, Dalton, ind Thomson Dalton M n <K d the value of the atomic 
weight as being between 140 and 200 (0=7) In 1813 Berzelms 2 
formulated uuous oxide is AuO, and auric oxide as Au0 3 , the corre- 
sponding vtomic weight being Au~2486 (0=^100) or 2x 198 8 (0 = 16) 
This ligme is ibout twice the modem value An =197 2 In 1826 
Bei /chits \v is induced by <i knowledge of the existence of oxides of the 
type U 2 ^j to ^sign to gold 1he atomic weight Au 1243 (0=100), 
corresponding \\ilh ATI 108 S (0- 16) nul to foimulatc the oxides of 
gold is An 2 () m<i ViijO, J it<i h< substituted loi these formula the 
so c illcel " jui\ ilcnt formul it " wiitlcn with letters hiving i central, 
hoi i/on I 1 1 shok< \\\ l ind Au m , e oncspondmg with AuO xml Au0 3 
Ih took 21 r >S * is I lu eqniv ilc \\\ md 1220 105 (O -100) as the atomic 
weight o( gold 3 In 1S17 Me me eke give the viluc An 200, and in 
1S2() Gmelm gi\e is UK cqimilcnl Au 60 I itci, the ccjmvilent 
w is ISSUIIK el to Ix ichnlK il \\ilh Uu ilomie \ve ighl An l f )6 to 100, 1hc 
(OIK sponclmg foimiili (01 t IK o\i<!< s Ix ing AMillc n is AuO inel AtiO 3 , 
ind loi UK <hloii(l<s is \u( I mdAu(l| 

Th< pmuipil l\]xso( gold < ompoiiiids IK AnX ind AuX^ those of 
UK loinuih \n\ Ix ing not impiolnbly l<)inu<lb\ (oinbin ilion e>P the 
ollxi (\\oloinis J IK iloniK \\(ighl Au 1 ( )7 2 js sii]>]>oil( d by ciyo- 
s( <>pi( ind < !)iillios( opu obs( i \ ihons ol solul ions ol gold in of IK i nu I ils 
indu it ing UK mon ilomu il v <>l UK <l<m<nl Th( \ i])oni density o( 
>old Ins not Ix < n d< t< IDIIIK d noi I h it ol my ol ils compounds The 
domic IK it ( d( id il< d liom th< spdi( IK it ind the itonne weight 
1072 his UK not mil \ iln< (> I 1 lu < l( IYK nl is isomoiphous with 
(0])])d ind sd\<r Its ])!(>])< UKS ind lhos( ol its compounds lie 
(mic lions ol UK itomic \\ciglil 107 he longing to in demenLol the 
eh vc ntlnou ol ( loupl 01 ol UK IcnthiowoKJjoiipVIII of the pdioelic 
systt in ol Me nclc 1( ( If 

1 l<oi i hihlio^i iphv <>F k<>l<l ^ 1 >( >^ Mittillniw ofCold r thccl (Chifrm 100G) 

HII/<IIUM A ^ni^/n \ d \l<ul llundl 181 J, lH r > tithwuwt * J ISU 7 47 
1 Bci/LhuH Ldnbvclt tlir (tnmit r >lh < d Dusdm islVlStS 3, 121J 



34*2 OXYGH^ WITH AZOIE 

more vigorously than in common air , it is 
unfit for respiration, but does not so immedi- 
ately prove fatal as Dn Priestley and the Dutch 
chemists concluded Mr Davy found that it 
may be respired for two or three minutes , and 
that it generally produces sensations analogous 
to those of intoxication It is absorbed by 
water to the amount of about 80 per cent ac 
cording to my recent ttials Davy makes it 
only 54 per cent > but he was not aware that 
the quantity is increased m proportion to the 
purity of the residuary gas Dr Henry finds 
from 78 to 86 per cent This gas of course 
expels other gases from water, and is itself 
driven off unchanged by heat It is a re- 
markable fact, that water should take so 
nearly, and yet not exactly, its bulk of this 



gas 



Nitrous oxide, by long electrification, loses 
about 10 per cent of its bulk , some nitric 
acid is formed, and a mixture of azote and 
oxygen is found m the residuum , but no satis- 
factory decomposition is obtained this way 

All the combustible gases, mixed with ni- 
trous oxide, explode by an electric spark 

Nitrous oxide can be made to combine with 
the fixed alkalies , but the nature of the com- 
pounds has not been much examined 



GOLD 335 

Kruss's analyses of carefully purified and dried potassium aun- 
bromide, KAuBr 4 , were more elaborate In some experiments the 
percentage of gold m the salt was determined by reduction with sul- 
phurous acid, in others by heating the aunbromide in hydrogen With 
sulphurous acid the bromine in the filtrates from the precipitated gold 
was estimated as silver bromide , with hydrogen the loss in weight on 
heating m this gas, proportional to 3Br, was ascertained, and the 
potassium bromide dissolved from the residue by water was recovered 
and weighed, in addition to the gold The results were 

KAuBr 4 Au=100 35 461, whence Au=197 123* , 

Au 4AgBr=100 881021, ,,==197150*, 

Au 3Br=100 121678, ,,=197055*, 

Au KBr=100 60390, =197 374* x 

The work of Thorpe and Laurie 2 was published in 1887 Like Kruss, 
they employed potassium aunbromide as the basis of their research 
By heating, the salt was decomposed into gold and potassium bromide, 
the mixture weighed and extracted with water, and the residual gold 
weighed The amount of potassium bromide was ascertained by 
difference, and the filtrate containing this salt was analysed for bromine 
by titrating it against silver < to the procedure of Stas The 

silver bromide produced was also collected and weighed The results 
were 

Au KBr=100 CO 331, whence Au=W7 272* , 
Ag Au-100 182827, =197 234* , 
Au AgBr-100 95208, =197 248* 

The cl ibontc usc<uch of Mallet 3 ippcarcd in 1889 Extreme care 
was exeioiseel in this mvcshgition, ui ex implc of the refinement of the 
methods c mployt d be mg tlu substitution of qu irt7-sand for filter piper, 
to avoid K due lion o( the gold salts to the met il elm ing filtration 

All Millet's inilystsol uine e hlonelc , uu K bi omule , and potassium 
uiiibioinid( \\eic m ulc by Uu sum me I hod Ihe gold in one sample 
of the compound \\ is de(< mimed by Helming with sulphuious acid, 
colliding the ]>ieeipi(i(< IK itmg it in the vuuumoi i Sprengel pump, 
cooling ind weighing I<iom inollui s un])le the hilogen w is pre 
ei])it il! by i slight ( \< ( ss ol silvei nitrite picpircd Iiom i known 
weight e>( sil\(i met I h< excess ol silvei w is etc tc mime cl by titrition 
with i si uul lid solution ol hv, dmhtomu ic icl To ivoid we ighmg the 
gold s ills lhc\ \\(ie dissolved in witei inel weighed ]>oitions ol the 
solutions \ve i< < mplo\< d loi th< in ilyse s The lesullsweu 

(Audi) 5\g \u 100 WOK) whenee Au 197 J2W 
(\uHi { ) 5\g \u 100 00027 1W 181* 

(K\ul?i,) \\u t Au 100 l r )(S<) l<)7J r )7 l 

A hut he i se nes e>l d\< e \p< MFIK nls w is m ide to de le mum the ratio 
ol the dedmduniK il <e|iu\ il<nls ol golel ind silvn, by ]) issmg the 
sime <|uintit> ol < ledrie ity through solutions ol pot issinm lurocvimdc, 



1 The valiK cal< ulai< d fiom the ntioAu K Hi has hi< n in< r< isl l>y 29 r > tocoruct 
it to vu iiuin stiimlai<l < onipin Hi mm r \h/(/ nnd Aiutluuk s Ilandbuch der auotqan 
idc/jcn f'/uwie, 1 (ipsu 1 ( )()S 2 i 758 

IlioriH and laiirit 7/ws ( huti /Sw 1S87 51 5G r > 80f> 

3 Malic t Pint Titnit 188 f ), 180 i ( ) r > 



344 OXYGEN WITH AZOTE 

derived from the nitre, which usually contains 
some muriates mixed with it To obtain th^ 
acid pure, the nitre should be repeatedly dis- 
solved in warm water, and crystallized, taking 
out the first formed crystals for use , and the 
acid, when obtained, should be treated with 
nitrate of barytes to precipitate the sulphuric 
acid, and nitrate of silver to precipitate the 
muriatic *acid 

The theory of this process is well under- 
stood nitrate of potash is a compound of 
nitric acid and potash , sulphuric acid has a 
stronger affinity for potash than nitric , it 
therefore displaces the nitric, which with the 
water of the sulphuric acid and that of the nitre, 
is distilled by the heat, and the compound of 
acid and water constitutes the liquid nitric 
acid above Near the end of the process, the 
heat is advanced to 500 and upwards, and the 
acid is partly decomposed , some oxygen is 
given out, and nitrous gas, which combines 
with the acid, and forms nitrous acid vapour 
This acid becomes mixed with the nitric, and 
renders it more fuming and volatile The ni- 
trous acid may be driven from the liquid nitric 
by heat, and then the last becomes less volatile, 
and colourless like water 

The specific gravity of the liquid nitric acid 

f rom j ^ to j rj g v 



GOLD 337 

prepare it free from gold and auric chloride, and there is much divergence 
in the temperatures cited by various experimenters, the values ranging 
between 120 and 300 C * The auric chloride can be washed out of 
it by means of ether, but it is difficult to prevent decomposition of the 
aurous chloride into auric chloride and gold under the influence of traces 
of water 

8AuCl=AuCl 3 +2Au 

The decomposition by water is accelerated by rise of temperature 

The chloride 2 is a yellowish- white substance, soluble in aqueous 
alkali-metal chlorides 3 with formation of complex anions, the solutions 
soon decomposing with precipitation of metallic gold and the formation 
of complex auric derivatives The transformation is more rapid m 
bromide solutions At 110 to 120 C aurous chloride and excess of 
phosphorus trichloride combine to form a double compound of the 
formula AuCl,PCl 3 , colourless prisms insoluble in water 4 

Aurous bromide, AuBr When auric bromide is heated, bromine is 
evolved, and aurous bromide left as a green mass 5 It is also formed by 
heating auribromic acid, HAuBr 4 , the auric bromide formed decompos- 
ing at 115 C Above this temperature it is decomposed into gold and 
bromine, and reacts with water like aurous chloride Aqueous hydro- 
bromic acid converts it into gold and auribromic acid, HAuBr 4 

SAuBr =AuBr 3 +2Au , 
AuBr 3 +IlBr=HAuBr 4 

It dissolves in solutions of alkah metal bromides 6 

Aurous iodide, Aul The iodide is produced by decomposition of 
auric iodide it oidin try tempciaturc, by the interaction of auric oxide 
and hydtiodic a< id 7 , by punpitahon ol aunc chloride with potassium 
iodide, 8 hydrogen iodide, 01 ft nous iodide , by the interaction of gold 
and iodine m (tlui solution or in i seiled tube at 50 C, or feme 
iodide, 01 minguust tell nodide 9 , by boiling powdered gold with 
hydnodu u id iml mhio acid, filt( im#, ind pouring the hot filtrate into 
aqueous hydnoelu u id 1() uul by UK interaction of aurous chloride and 
potassium iodide u 

Auions iodide is i lemon yellow powdei, ami is veiy difficult to 
prepau in the pme si lie is il is ele eemipose el l>v moist nr at ordinary 
tempt i iliues I he exeess ol loeline is he si eliminited by sublimation 
it 30 ( Tt is ele (oinpe)se el hy lu il ing with w ite i dilute sulphmie aeid, 



I Dunmti JI<ni(itni(h <lu iui<>n/<tnivh< u (hi tun Mutton! l^ ( )l 3 701 Bcrzelius, 
Lfhtbiuh (lu ( Intnn tfh l Ih<sd<n ISt r > 1HI1 4 <><)! I lionise n 'r/uimodie/Mwhe 
UnhrtnrlutmitH ItipsK ISH2 ISSJ 3 $S(> I < u< hs / pialt ('turn 1872 \2] 6 1*36 
KIUHS InnulLH 1SS7 237 270 

( ompan Ditnui / \mtt (lion \<>< M)M 35 r ) r >2 
J I < ii^f< Id Itmr ( lutn / 1<)OI 26 12 1 
4 IimUt C'o//i/>f KM! 1SS) 98 I {S2 (oinpin Alxgfe At itvli aunty Chem 1904, 

39 *" 

r Jurnand M< \( r ( ompl u ml !<)()<) 148 U(> 
(t I < n^f( Id !<>( rtf 

7 ( omparo I'ellotiii Cnulin hiautv flandbiuh tier anoryamschen Chemie, 6th ed , 
Hudolbcrg, 1872-18 ( )7, 3 L015 

8 JHordoH / 1'harm 18 il 27 b r )^ 

9 Tomparc NK 1 l^s Ann Chun Phyt , 1867 [41 10 ^18 Compt rend 1866 62 
705 63 21 

10 Compan Cnxlin Kiaul llandbucli dcr arwn/annchen CJiemie 7th ed Heidelberg 
1914 5 u 2S2 

II (ompui lu inand M<>( i Cwnjit und 1001 139 7iJ 

ve^i ii 22 



5 16 O\ YGEN WITH A2OTE 

charcoal, essential oils, c 7 When dis- 
tilled over sulphur, it converts the sulphur 
into sulphuric acid 8 It oxidizes the metals, 
as has been obseived, and gives out nitrous 
gas 9 When the vapour of nitric acid is 
passed through a red hot earthen tube, the 
acid is decomposed into oxygen and azote 
The same decomposition is effected by heating 
nitre red hot in an iron or earthenware retort 
10 It unites to the alkalies, earths, and me- 
tallic oxides, forming salts denominated m- 
ti ates 

One of the most important considerations 
relative to nitric acid is the determination of 
the quantity of real acid in a watery solution 
of a given specific gravity This subject has 
engaged the attention of several eminent che- 
mists, particularly Kirwan, Davy, and Ber- 
thollet Their results are widely different 
For instance , in an acid of 1 298 sp gravity, 
Kirwan sajrs the real acid is 3o^ per cent 
Daw says 48, and Berthollet 32 or 03 (See 
Journal de Physique, March 1807)* My 
experience in regard to this particular has 

* Berthollet, by im&take, makes Davy represent the 
acid in question to contain 51 per cent of acid , hut it is, 
theuater \\luch he says is 54- pei cent and the icid k> a 
when the sp gravity is 1 283 , so tl at the diftertnu, gieal 



GOLD 339 

cyanide With sodium sulphide x and with potassium sulphide, 2 aurous 
sulphide forms double sulphides of the type NaAuS 

Complex Derivatives of Aurous sulphite Although aurous sulphite 
itself has not been isolated, double sulphites of aurous gold with sodium, 
potassium, ammonium, and barium have been obtained 8 The sodium 
salt is formed by the interaction of auric chloride and sodium sulphite 
in alkaline solution, or by the action of sodium hydrogen sulphite on a 
boiling solution of a gold salt, or by that of sulphurous acid on a similar 
solution at 30 to 50 C It has the formula Au 2 S0 3 ,3Na 2 S0 3 ,3H a O or 
Na 3 Au(S0 3 ) 25 lpI 2 0, con 1 mm j the complex amon Au(S0 3 ) 2 '", since it 
does not display the reactions characteristic of sulphites It is readily 
soluble in water 

The < M > sim forms white needles, and the barium 
salt is a purple-red, amorphous substance The constitution of the 
ammonium salt produced by the interaction of auric chloride and an 
ammomacal solution of ammonium sulphite is uncertain, but is given as 

2Au 2 S0 3J (NH 4 ) 2 S0 3 ,6NH 3 ,4lI 2 0, 
or 

5Au 2 SO 3 ,2(NH 4 ) 2 S0 3 ,10NH 3s 4H 2 O 

Aurous thiosulphate, Au 2 S 2 O v 3H 2 S 2 3 ,II 2 This substance is to be 
regarded as a complex aurothiosiilphtuic acid It is prepared by the action 
of dilute sulphmic aciel on the barium salt 4 

Sodium thiosulph itc u<icts with a solution of auric chloride to form 
sodium aw 



Au 2 S 2 } ,5Ni 2 S>0 ,!!/), or Na,Au(S 2 3 ) 2) |H 2 O, 

colomlcss, uuul u eiystils A1 T5() to 100 C it loses water, and at 
highc.ite.mpu it UK sit is d< composed I lydiogcn sulphide and ammonium 
sulphuk pieeipitite mioiis sulphide iiom its solution ind iodine 
tiinsfoims it mlosoelmin U h illnon lie inel unoiisiodide In accordance 
wilhlhe ])ies(ii(( ol i(oni])l(\ mion hyehoe hloiu <uiel ind sulphuric 

leiel elo nol ])K(ij)it ile sul])hui \ eonli is! 1e> then ution on orelmary 
thie)siil])h il< s r l he >m]>l< \il y oMhe mum is (uith( i m inifesieel in the 
in ibilit y ol t h< usml yolel i< <Iu< < is (o ])i< ( ipit it( t IK met il 

Aurous Denvitivcs of Nitrogen- Ainons oxide md iminom i 
combine to JOHN in explosive piexlnel 5 An { N Nil { ,4II 2 O 6 Wlicn 
hoi h d \\il h \\ il< i h ill ol I he ml n>u< n is < 1 mi m lie el, wi1h loim ition of 

mol he i nilndt Vn { N r >IM) \ highly e xple>sive anrou** Infdiazocrte has 

ilso Ix < n |)i< j) u < el 7 

Aurous cy mich., A n( N r l he cymiele is ])ie>elue e el hy the intn ution 
of h\die>ife n < \ imele ind nine h\ dioxide 8 by elonhle ele composition 



1 Anl<>nv uid I u< i In MI ( a did IS<)(> 2611 { r >0 Dainmu llamlhntlitJcrtni 
Chemu, Million it Ih<H 3 70 ( ) Yoila / itbu/ and hopp s J aim ^benefit fur 1847-1848 
(JiesM<n ISt<) !">! 

2 \oil( I<H at Olxil inipi inn (linn ISII 80 NO )ni|)ii( Ilofiuanii ind 
Ilodill* n /></ l ( )(>{ 36 {0 ( )(l 

1 Hansi luinuhnuj ion >,< liu < /lii/i > \<UIK ttnl Colthhlnmt PoslocU 18(> ( ) Knt 
/at Chun 1S(> ( ) 12 r > r> mi|)U< I os< nln nn ildt/nunn indPiit/c /ft/s(/< anon/ 
Client 1<)OS 59 1<)8 

1 lM)i<loH and ( thH Ann (him / ////s 1S1 > { t] 13 i<)4 
I iguitr ibid, 1SH | t] II JJ<) 

Hischi^ \nnal<n 1S8(> 235 U ( ) 

7 (uitius uid Hissoni / inukt Chun 1SOS |2| 58 2(>1 

8 Daninit i tlnndbnch dct anoryamschen Chume, Stuttgart, 1803 3 774 



348 OXYGI NT WITH A2OTE 

Percival has noticed some results in the distil- 
lation of nitre , 2lbs of nitre and 1 of concen- 
trated sulphuric acid were mixed and distilled , 
the products were received in 3 portions , the 
first was of the strength 1 494 , the second, 
1 483 , the third, 1 442 Proust, in the Jour- 
nal de Physique, 1799, relates that he obtained 
an acid 1 52 , this being again distilled, gave 
for the first product 151, for the second, 151, 
nearly colourless, which he expected indicated 
a superior specific gravity , but what surprised 
him more, was to find the residue colourless, 
and 1 47 This residue was distilled , the 
first portion was 1 49, and the rest 1 44 In 
another instance an acid 1 55 was obtained, 
this redistilled gave, first 1 62, the second 1 53, 
and the residue was 1 49 From all these 
facts, it appeared to me reasonable to conclude 
that an acid of some one strength, and only 
one, was incapable of any change of strength 
by distillation , or was of such a nature, that 
the distilled part and the residue were always 
of the same strength and specific gravity The 
actual strength of this acid was a desirable at* 
tamment , for such an acid evidently marks a 
nice adjustment of affinities between the acid 
and water , or a kind of mutual saturation of 
the two By icpeated experiments I find this 
to be of the specific gravity 142, it is 



GOLD 341 

of this compound has been a matter of dispute, 1 and it has been assumed 
to be a moleeular compound of the formula AuCl,AuCl 3 , containing 
equimolecular proportions of aurous chloride and auric chloride 
Thermochemical data indicate that this assumption is incorrect 2 

Golddibromide, AuBr 2 Bromine converts powdered gold at 170 C 
into the dibromide, a black substance slowly soluble m water with 
decomposition 3 It is also decomposed by heat, and by the action of 
acids The individuality of the dibromide has also been disputed, 4 but 
it is supported by thermochemical evidence 5 

Gold monoxide, AuO An oxide of this formula is said to be formed 
by the action on gold of a small proportion of aqua reg^a containing excess 
of hydrochloric acid, addition of sufficient primary carbonate to the 
solution to redissolve the precipitate first formed, and heating the solu- 
tion 6 The product separates as an olive-green hydrate, which dries 
in the air to a hard mass It is doubtful whether the oxide is a true 
chemical compound or not 

A hydrated gold oxide of the foimula Au 3 2 (OH) 2 is prepared by the 
aetion of boiling water on the monosulphate, AuS0 4 7 It is a deep- 
blaek powder, dceomposed at 160 to 205 C 

Gold monosulphide, AuS Hydrogen sulphide or an alkali-metal 
sulphide pi ccipitatcs the moixosulplude from solutions of auric chloride, 8 
and it is also pioduecd by the aetion ol hydrogen sulphide on sodium 
aurothiosulphat( It is a blaek substance, insoluble in acids except 
aqua tegia> but soluble m alkili-mefcil sulphides 9 

Gold monosulphate, AuS() 4 - Kvapoiation ol a solution in con 
cenli iled sulphuiu ieid it 250 C oL the so eaileel and awyl sulphate, 
AuOllSO 4 (]> 3J<7), yields 1 #( eiysl ils ol the monosutphatc 10 It is 
eh u i< tcii/ed by Us sc ulet icdcoloiu Exposure to moist an eh mges it 
into the bla< L hy<h itcd monoxide 

Nitride of Bivilcnt Gold Atnmom i couveits gold monoxide into a 
niludc ( on! lining gold mil mi logcii in the atomic piopojlions 3 2, but 
difftuul horn tin |)io(lu(t loinud by lh< inUiuhouoi uuiuouia and 
auious o\i(U ll I IH it i< lion is possibly c \pusscd by the equation 

J\u() | 2NH, Au a N 2 | 31U) 

UK subsl im ( is (\|)losi\( ind is u ^uded by Hisdng is pjobably 
hiving I IK ( onslilulion 

no AU 

no AU;N Nil, 

110 Au/ 

M(.inpu( Kniss uid Sdmiidt />< / 1SS7 20 20 ' 1 / /*/</// ( linn ISSS |2J 38 
77 llioins.ii ,hnl ISSS |J| 37 10 > IduMii ihnl IS<U \2\ 46 J2S 
2 IN IUMII / fnlt ( fnm 1S<)J |J| 46 US 
Ilionis< n ihtil ISSS | J) 37 {S(> 
Kru s ind S, hniidl ilml ISSS \2\ 38 77 
I i((isn ifjitl IS'IJ \2\ 46 UK 
l'i it < omiit )uid 1H70 70 H4t) 
SchollliiMld [ninth n I SK i 217 M7 
8 Ohdl uiij.f Inn ( Inm ISI1 80 110 (oni])ii< I < vol ibnl 18 r )0 \\\ 30 350 
bclldilKi^ I>t>w \nnal(n 1840 50 71 llollnumi unlKiiiss lln lhS7 20 270 r ) 

Outbid an<l Dunwadilci (/mlsth anon/ UILM L ( )22, 121, 200) failed to piopaio 
this Hubatanco 111 acoordanco with tho htciatuio 

10 Sohottlandd 1 nnaloi, 188 i 217 3 J7 

11 Kaachig ibid , 1880, 235, 551 



350 0\\GEN WITH AZOIC 

la calculate the real acid in the said solution 
Now, 106 grains of 1 51 nitric acid + 248 
grains of a solution of potash 1 482, with wa- 
ter, gave 665 grain measures of solution of 
nitre of i ISO sp gravity, indicating 15O of 
pure nitre Hence 106 grains of the acid con- 
lamed 71 a, or b7 per cent which is l per 
cent less than Kirwan deduces it , and this 
may partly arise from the escape of some acid 
by its mixture with water producing heat. 
Again, 133 grains of 1 42 aud were saturated 
with potash , they gave 672 measures of 1 13 
solution, indicating 152 nitre, hence 133 acid 
contained 72 real, or 54 per cent which nearly 
agrees with Kirwan's Again, 205 grains of 
1 35 acid were saturated with 29O grains of 
1 48 carbonate of potash , this diluted gave 
850 measures of 1 13 solution, indicating 192 
nitre , that is, 205 grains acid contained 91 
real, 44 t per cent which also nearly agrees 
with Kirwan Again, 224 grains ot 1 315 
acid, took 300 grains of 1 458 carbonate of 
potash , thrs diluted gave 804 measures of 1 13 
solution, indicating 192 nitre , that is, 224 
grams of acid contained 86 5 real, = 38 6 per 
cent 9 this is extremely near Kirwan's es- 
timate 

Being thus satisfied with the near approxi- 
mation to truth of Kirwan's table of nitric acid 



GOLD 34 

A test of the purity of the salt is its complete solubility in ether * 
It is unaffected by the prolonged action of radium bromide 2 

In dissolving alloys of gold and silver in aqua regia in presence of 
ammonium chloride and nitrate, purplish-brown crystals of the formula 

8AgCl,4AuCl 35 8NH 4 Cl 
are sometimes obtained as a by-product 3 

Aunchloric Acid, HAuCl 4 A solution of this substance is produced 
by the action of hydrochloric acid on auric chloride, or by addition of 
excess of this acid to a solution of gold in aqua regia to decompose the 
nitric acid present It crystallizes in yellow needles, which deliquesce 
in moist air to a yellow solution 4 The acid exists in the form of two 
distinct hydrates, one with three 5 and the other with four 6 molecules 
of water, the individuality of the two being indicated by the heats of 
solution 7 In the solution of this acid the gold is present in the anion 
AuQ 4 ' 8 Its action on potassium fcrrocyanide has been investigated 9 

A great number of aunchlondes is known Potassium aunchlonde, 
K AuCl 4 , is prepared m the anhydrous form by evaporating a solution of 
auric chloride in eoncentratcd hydrochloric acid m presence of potassium 
chloride 10 It melts <xt the temperature of boiling mercury 11 It is also 
known as sennhydrate and dihydrate 12 It dissolves readily in water 
Heating eonveits it into pot issium c^uroehlorldc, KAuCl 2 

Sodium aiincldondc, N<iAuCl 4 ,2lI 2 O, forms rhombic columnai 
crystals or 1 imnut 13 Its Wdtu oi eiystalhzation cannot be expelled 
without * the s Lit, i distmetiou liom the potassium deuva 

tive Its solubility m ctlu i is uiothu elm utenstic point of diffeience u 
It can be employed is i test loi iodides in presence of biomidcs, the 
libciateel ioelm< imp u I mi; i \ jolt I ( olour to chloioform 15 

Two anunonuun uundilotidn ut known 



lNII 1 \uCI 4 r >U/) 1 inel 21 

UK insl is j)Kj)U(d in > ( How, moiuxlmic plitts lioni i solution of 
nine ehlonde mconeenh ih d hydien hlonc u lehn ])uscnceol immonium 
ehlonele , the s< < ond in \(llo\\ 1 mini i lioni ineutiiloi slightly leiehc 
solution ol iiiiu <lilotid( At 100 I 1 they givt up tlie.ii watei ol 
e i vsl ilh/ it ion md it hiih< i t( inp( i it uus decompose 

1 I i ml S/////M ]\<nlnnvh < In in 1'lnitin 1 ( )1J 51 J8() 

i(i!iiui I nin ( In in Sor 1 ( H)S 93 I77 r ) 
1 I oil lid ibitl l ( )2l) 117 <)> 
1 l(i/<lms /</n/nn/i ,1, i ( In inn r >tlil Dnsdui IS1J-I8IS 4 (><)2 

\\ < ()( i / o<i i 1 tun 1 1 n I S(>7 151 11) S< Iml 1 1 uulu 1 iinnli n \ SS \ 21 J \\2 
' llioiiisiii I In i mix /nun sr In I nt i s//< linn<i< n l(ipsi< I SS2 I SS { 3 {S2 
7 ( nmpm 1 ( n_l( Id \nui (lion I I ( )<H 26 \2 1 Sdnnidt Ijtothtl u Zut 11)00 
21 ((>! 

H Ihltoif / <// \ninil n IS ><> 106 r )J J 
'( ui< 1 J/ow//s// IMK) 31 S71 
inn i ihnl 1S<)() u JJO 
|)ln inn / M l ( )|<) ^2 | B| Jl I 

(>|>s()( (mnlin A/rf/f/s ll<unl(ni<li <l< / dinni/aiit^ /ttu CltditK (>tli c-d , Hcidtlbcj^ 
1S<)7 3 10 iO 
'olllp lit I opsoi / H < // 

islx iid( i \M/// li)d(h linn in IS<M 6 i 2J7 
( K h mil / luuni /i if I MOM "54 >S 

( lopsot Cnnhn knuil s llninllnnh <l< / <ui<>i<i(t)nv In n ( In nin bill cd 
Ib72 1S<)7 3 inj(> 

17 lojisoi //;/r/ (\\ith Dumstiulld uid hoicliluinnid) 



352 OXYGEN WITH AZOTE 

potabh, ga\e 66 grains of nitre, at 212% and 
this became 60 by fusion in the other, 90 
grains of 1 504 acid, saturated w,th potash, 
gave 173 of dry nitre In all the similar ex- 
periments which I have made, I have uni- 
formly found only three quarters of the quan- 
tity of nitre said to have been obtained above, 
from given quantities of the acid I conclude, 
therefore, that Mr Davy must have committed 
some oversight in these two experiments, and 
that the direct formation of nitre from nitric 
acid and potash, accords only with Kirwan's 
estimate of the strength of nitric acid 

Berthollet, in the Journal de Physique, 
March 1807, informs us, that he saturated 100 
parts of potash with nitric acid of 1 2978 
strength, and obtained 170 parts of nitre ? he 
calculates the acid to contain 3241 percent 
real, by which we may infer that 216 grains 
of it were required Nitre, according to this, 
would be 100 potash + 70 nitric acid, or 59 
potash + 4 1 acid per cent This is much more 
potash than ever before was detected in nitre 
How are we to be satisfied that the potash 
used contained no water ? If it contained any 
water, this would disappear m the process, 
and its weight be supplied by nitric acid, 
which would not be placed to the acid's ac- 
count That this was the real fact I have no 



GOLD 345 

powder At 160 C it is completely transformed into aurous 
bromide 1 m the ioim of a green mass, 2 and bromine When prepared 
by the action of bromine on precipitated gold, it forms black crystals, 
volatile in bromine at 300 C 2 

Aunbronuc % Acid, HAuBr 4 Solutions of auric bromide and of gold 
in bromine-generating liquids are converted by hydrogen bromide into 
a solution of auribromic acid The substance is also formed in solution 
by the action of the same reagent on a solution of auric chloride, and 
can be extracted by ether from the dark-red liquid 8 Evaporation of 
the concentrated aqueous solution yields the acid in dark-red crystals 
of the formula HAuBr 4 ,5H 2 O * or HAuBr 4 ,6H 2 0, 6 melting at 27 C 
in its own water of crystallization, and decomposed by concentrated 
sulphuric acid at 155 C into aurous bromide and bromine 6 

Potassium auwbrormde, KAuBr 4 , is produced by the action of bromine 
on gold and the equivalent proportion of potassium bromide 7 On 
evaporation of the solution, potassium aunbromide crystallizes in dark- 
red prisms containing two molecules of water of crystallization 8 , and by 
drying the crystals over phosphoric oxide it is obtained in the form of 
purple-red, monoclmic crystals 9 free from water On exposure to air, 
it takes up two molecules of water 10 Its solubility at 15 C is 19 53 
grams m 100 grams of water 

Ammomum aunbrormde, NH 4 AuBi 4 , is produced by the action of 
ammonia on the acid, and ioims bluish-black crystals of fat-like lustre 
The anhydrous 1ub^d^um and c&wum salts give prisms of metallic 
lustre, the colom ol the first being cinnabar-red, and of the second deep 
black " 

Auiibiomides ol sodium, 1) uiuin, /me, m uigaiiesc, 12 and magnesium 13 
hue been pup nod lnplc biomidcs ol gold, silvei, and lubidmm (or 
c i sunn) h ivc ilso be c u elcsenbed 14 Double compounds of auucbiomide 
uid phosphorus de m dwes < in IK obi mud by methods < to 

those employed ioi the (one s|>emelm<j ehloime ulditioii-pioducts 15 

Auric iodide, Aul } Gi ulual leleliiion of a solution of aune chloude 
loom ol |)ol issium iodide yielelseomplcx Aul 4 ions, eoavcitcdbyluithei 
lelditiou ol IUIK (hlonde into auue lodiele 1G 

*\uI 4 ' | Au 'lAuI 3 

()ii(li>m<> the dukijiun piodud de>m]>os<s mio ituous loeliek iud 
loeliiu Jl is soluble \vilh ehiheuUy m w ilei to m unstable solution 

1 Sdmndt ( In in /< il IS ( )<> 2O 1st 

Imnuid M( \< i ( <*mi>l ><n<l 1 ( H) ( ) 148 tl<> 

a ( u( l)Ki ind Unix i /M/W/ (ui(</ C/KHI 1 ( H1 85 t r > i (oitipiM (JnulinhmutA 
ll(ui(thu( h d( t (nniK/ani^Uu u ( 1 htmic (>(h o<l Ucidclbot^ 1S72-1S07 3 IOIO 
4 I homs( n Tint HUH limn vht Wult IMH hitm/i n I<i|)MH 1882-1883 3,390 
& I < njdd \itni ( /m / 1<MU 26 JJ 1 
S( liiMidt ( lnm /<// 1S<)<) 20 1SJ 

S( liotllaud* i \nmil ti iSSt 217 $15 
K ( uU)K t ind Unix i lot < il 

( oiiipin MuthiiMiin \nna!<n 18S7 237 J5 r ) ( ) housdoifl 1 (></</ \nualui J8JO 
19 U<> IStl 33 (>1 

1(1 ( < inp IK Muihiii mil lt>< ( it 

11 ( ut UK i ind Hulx i l<x < il 

1 I nnsdoiil / <></</ \nn<il<n 1SJ ( ) 17 2(>I ISU 33 (> 1 
n I uidis / i>ntlt < Innt I S72 |2| 6 I r >0 

11 Suschmj, Moiuthh 1921 42 W 
1 Iindct Coniftt rend 1885 101 U>4 
18 Johnston, Phil Mac/ 1830, 9 260 



354 OX\GEN WITH AZOTE 

except the first and second column, which ln 
table has not, and the three last, where I think 
he has overrated the quantity of acid , indeed, 
the lower part of his table is confessedly less 
correct I have already given my reasons for 
considering his tab ! e as approximating nearest 
to the truth , but have no doubt it might be 
made more correct, I have, therefore, only 
extended the table to two places of decimals 
in the column of specific gravity The column 
of acid per cent by measure, uill be found 
convenient for the practical chemist The 
first column shews the number of atoms of 
acid and water in combination or collocation 
in each solution, agreeably to the preceding 
determinations , namely, an atom of acid is 
taken as 19 1 by weight, and an atom of wa- 
ter as 8 The last column exhibits the boiling 
points of the several solutions, as found by 
experiment Those who wish to repeat these 
experiments, may be informed that a small 
globular glass receiver, of the capacity of 6 or 
7 cubic inches was used, 2 or 3 cubic inches 
of acid v\ere put in, and then a loose stopper 
It was then suspended over a charcoal fire 
When signs of ebullition began to appear the 
stopper was withdrawn, and a thermometer, 
previously adjusted at the boiling point of vva- 



GOLD 347 

produced, and addition of sulphuric acid liberates auric hydroxide, 
AuO OH,H 2 O, which is converted by alkalies into the corresponding 
aurate, M'Au0 2 or M // (Au0 2 ) 2 , containing water of crystallization The 
products are pale-green, acicular crystals, the dry salts being stable to 
heat They are reduced by sulphurous acid and by alcohol to metallic 
gold Dilute sulphuric acid and nitric acid yield the corresponding 
metallic nitrate and auric hydroxide , hydrochloric acid produces the 
metallic chloride and auric chloride The calcium, barium, and mag- 
nesium salts are not readily soluble in water 1 

A complex derivative of auric oxide and higher oxides of manganese 
has been described 2 

Auric sulphide, Au 2 S 3 Gold docs not combine directly with sul- 
phur, 3 but at 2 C a rapid current of hydrogen sulphide transforms 
aurichloric acid, HAuCl 4 , in dilute solution m normal hydiochlonc acid, 
into pure auric sulphide 4 Lithium aurichlonde, LiAuCl 4 ,2H 2 0, at 
10 C is converted by hydrogen sulphide into a mixture of lithium 
chloride and impure auric sulphide, with evolution of hydrogen chloride 
After extraction of the lithium chloride with alcohol, the sulphide is 
dried in a eurrent of nitrogen at 70 C 5 It is an amorphous, black 
powder, at once decomposed by the action of watei At 200 to 205 C 
it is converted into a mixture of gold and sulphui It forms double 
sulphides with the alkali metals 6 , and also unites with the sulphides 
of elements ol weak positive, 01 even of negative, character, sue 
arsenic, tclliuium, molybdenum, and carbon 7 The last class of com- 
pound is piobibly to be re girded as an iuric salt of a complex acid 
containing sulphm uiel one oi the elements mentioned 

Aunc sulphate, Au 2 (SO 4 ) 3 The sulphate has not been isolated 
Gold dissolves m comcnti ited sulphuric Kid in piesencc of a small 
proportion of uitiic uiel, Jormmg i yellow liquid, but dilution lepre 
cipitates the gold eithei is the hydioxtdc, oi m presence ol icduccrs 
as the met il 8 The mine uiel e in be upl iceel by othei oxichzcis, such 
as loelie ieid y ind in inline sc dioxide J0 , md i solution oi the sulphate is 
also tonne (I by 1 he idionol concc nti ih el sulphunc icidon nine oxide 11 
Acid auryl sulphate, Au()IIS() 4 r llns sulphite is pioduccd by the 
ution of e one c nti iled sulphune Kiel e>n unie hydioxiele it ]8() C, 
the bioun b ISK sill loi me d b< mjj < onve i (e el by he iting it 200 C into 
I he ye How i< id unyl sulph lie u II is decomposed by w lie i with lonna 
turn ol nine hvdio\id( bill dissolve s in < one ( nil lie d sulphune melto i 
yellouish leel solution !ie>m AY 1m h it s< p u itcs uiuh ini>( (I When this 
leiel solution is IK it<d \\ilh pol issunu hyeho^cn sulphite, i yellow, 
eiyslillint sill ol the lonmil i k\u(S() 4 ) 2 se |> u lies It is inoie st ible 
thin ic id iui} 1 sulph lie, but is slowly decomposed by w ilci, with 

1 Wu^uul /ntvh <iii<j<n ( In ni I ( M)0 19 I W 
S< hnltl md i luntilin ISS5 217 t!0 

>nii>t ninl !<)<)<) 148 1170 \nu Chun /V//ys M)0 ( ) JS| 17 r >20 
il Dmiwulitu /<il^</i <iiioi</ ( In in 1 ( )22 121 200 

lluh(si ( <t <tl 1SS<) 19 r >l r ) IS<)0 20 (>0l 
.'in. ifr/ ( hun I ////s 1 ( M)7 |S| 12 2J ( ) 

7 I'd/dins 1 dnbiuli <tn < Inmu Oihcjl Dicsdci) IS1J-IS1S 3 (><)H 
^ I(>no!rls ( hnn \ / // s IS(>I io l(>7 S|>ill( i ibid 17 J Alh n ibu! 1S72 25 85 
J Ii it Dun t ln s l>itli/th / IS70 198 r ><) 

10 I < nlu i I< l<(ho< In HI I nil 1 ( )()1 2 il() 

11 Comptuc GimhnKriut, llatidbuck dcr cmonjani^cliui ClumiL, Oth cd Heidelberg, 
1872-1897, 3 1014 

1 bchotlUndu \\icd Annalcn 1S83 217 308 



Anini\ in 
Dill* I/// 



r $58 OXYGEN WITH AZOTE. 



Remarks on the above Table 

1 It seems not improbable, but that an acid 
free from water may be obtained, as repre- 
sented in the first line of the table That such 
an acid would be in the liquid state, but with 
a strong elastic steam or vapour over it, at the 
common temperature, is most probable , in 
this respect it would resemble ether, but per- 
haps be more volatile Seventeen per cent of 
water would bring it down to acid of the se- 
cond line, and such as has actually been ob- 
tained by Proust This last would nearly 
agree with ether in volatility With respect 
to the specific gravity of pure nitric acid, it 
must be less than 1 8 , because a measure of 
that sp gravity mixed with a measure of wa- 
ter, would make 2 measures of l 4, if there 
weie no increase of density > and acid of this 
density is nearly half water * I apprehend if 



* The theorem for specific gravities is -f-~ = H + 

S s J 

where H represents the weight of the body ot greatest 
specific gnmty, S its specific gravity, L the body of least 
specific grauty, s its specific gravity, and / that of 
the mixture or Compound Hence in the case above, 



1 ~" 1 4- 



GOLD 349 

Silver nitrate reacts with aurichlonc acid in accordance with the 
equation 

4AgN0 3 +HAuCl 4 +3H 2 0=Au(OH) 3 ,4AgCl+4HN0 3 

The brown precipitate formed is converted by ammonia into fulminating 
gold, which after drying explodes violently downwards when touched 
with a knife Jacobsen regards it as having the constitution 
Au(OH) 2 NH 2 or (AuN,2H 2 0),H 2 When boiled with potassium- 
hydroxide solution, it is converted into a blackish brown substance of 
even more explosive character, probably having the constitution 
Au(OH) 2 NHAu(OH) 2 

Auric nitrates Complex derivatives with the amon Au(NO 3 ) 4 ' are 
known Auric hydroxide and nitric acid yield a substance of the 
formula HAu(NO 3 ) 4 ,3H 2 0, crystallizing m octahedra, and soluble in 
concentrated nitric acid l Aurmitric acid melts at 72 to 73 C , and its 
density is 2 84 When heated above its melting point, it is converted 
into a black substance, possibly auric nitrate, Au(N0 3 ) 4 Aurmitrates 
of rubidium, potassium, thallium, and ammonium have been prepared 
From the ammonium salts a yellowish brown, explosive substance, 
similar m properties to fulminating gold, has been obtained Several 
basic nitrates of gold are also known 

Compounds of Gold and Phosphorus Phosphme reacts with a 
solution of auric chloride in anhydrous ether, forming aunc phosphide, 
AuP, a substance decomposed by water or potassium-hydroxide solution, 
with foimition ol phosphmc and phosphoric acid 2 At 100 to 110 C 
it * oxidation in the air Heating m a current of carbon 

dioxide causes volatilization of phosphorus Nitric acid oxidizes the 
phosphorus, leu ing i residue of metallic gold These reactions in- 
dicate the subst me c lo be in illoy of gold and phosphorus 

Gold phosphides - Gold s< <*qmpho<ipJnde, Au 2 P 3 , is said to be formed 
by he ilmjjf -phosphoius with i^old 3 

Anotlu i ])hos])lml( , Au^l^ is pioduud by the interaction of phos 
phonis \ ipoin ind i^old 3 11 is itfny buttle subsHnee of eknsity 
G f>7 md is ioiml only in tin luighbouihood of 400 C 4 Aeiels react 

\vi1h il is \ut h in illov 

Gold arsenides Aisnne pi< < ipii it< s Iroin uuie ehloiiele solution 

in usdiid< \n^\s r> IMISIOII ol thissubsl inee with ]>ot issinni ey unde 

eonv(ils il info i \cllo\v usdiuh, Au 4 As } e>f density 10 2 Both 

snbsl UK < s h IN ( UK < h u K l( i ol illoys 

Auric intimonidc, AnSb 'llussnbsl UK c is i\vhi1( brittle pioduct, 

ol (i(iisil\ 1115 It IxhiNcs is in illoy Ollui illoys ol f(>ld md 

mlmionv 11 ( known 7 

Auric cymide, \u(( N), Pol issnnn uincymidc is ti insfoimed by 

sliontf Kids such is hyhollnosilieie idd into unie eyunde r lhe 

K u Lion is nioi( coniplt \ I h in is indn it( d by llu ( qn it ion 

2KAu(( N) 4 | H 2 Sil< Mu(CN) 3 | K a SiI< 6 | 2IICN 

1 Schotll in<l(r \\i(d \nmil(n 18SJ 217 i r >() 

( i\a//i Caz^tla !SK r > 15 10 

i Sihroltd bit-uni/^Ht A Had >Kiss Wien 1849 2 508 
4 ( nnjjff r < 'mufti t<nd 18<)7 124 408 

*> Disc imps \lnd 1878 86 1022 I mdbom Bull 8or cJnm 1S78 [21 29 410 
r f'hiistollf ('mnbinaiiom d< I tiilinioiiK 1 Oottin^ n 1S(>$ 
7 Coinpan Dininui llamlbiirh dcr atwi tjamw'hcn riicnnc Stuttgart 1S<)5 3,773 



356 OXYGEN WITH AZOTE. 



Remarks on the above Table 

1 It seems not improbable, but that an acid 
free from water may be obtained, as repre- 
sented in the first line of the table That such 
an acid would be in the liquid state, but with 
a strong elastic steam or vapour over it, at the 
common temperature, is most probable , in 
this respect it would resemble ether, but per- 
haps be more volatile Seventeen per cent of 
water would bring it down to acid of the se- 
cond line, and such as has actually been ob- 
tained by Proust This last would nearly 
agree with ether in volatility With respect 
to the specific gravity of pure nitric acid, it 
must be less than 1 8 , because a measure of 
that sp gravity mixed with a measure of wa- 
ter, would make 2 measures of 1 4, if there 
weie no increase of density _, and acid of this 
density is nearly half water * I apprehend if 

* The theorem for specific gravities is -f = -, 

o s J 

where H represents the weight of the body ot greatest 
specific gmity, S its specific giavity, L the body of least 
specific gia\ity, 5 its specific gravity, and / that of 
the mixture or Compound Hence in the case above, 
1 8 1 2 8 



GOLD 351 

chlorides by heating the sulphides with a mixture of potassium nitrate 
and ammonium chloride l 

The metal can also be precipitated with hydrazme chloride in alkaline 
solution 2 The precipitate is freed from mercury, copper, cadmium, and 
bismuth by extraction with nitric acid, and the residual gold and platinum 
dissolved in aqua regia The gold is precipitated from this solution by 
the action of sodium hydroxide and hydroxylamme, the platinum 
remaining dissolved Another method is to precipitate tin, lead, and 
bismuth with ammomacal hydrogen peroxide, eliminate the hydrogen 
peroxide, and precipitate the gold with the mercury and part of the 
platinum by heating with hydroxylamme 

The presence of gold in any of the precipitates described can be 
detected by solution in aqua regia, and reduction to metallic gold by 
various reagents, including ferrous chloride, ferrous sulphate, mercurous 
nitrate, stannous chloride, hypophosphorous acid, oxalic acid, 3 sulphurous 
acid, hydrogen peroxide and potassium hydroxide, formaldehyde, and 
hydroxylamme hydrochlonde 4 

Among the reagents applicable to the detection of small quantities 
of gold 5 are alkaline hydrogen peroxide , ferrous salts , stannous 
chloride, which gives the characteristic purple coloration with one part 
in 100,000,000 parts of solution , alkaline formaldehyde, which gives 
a violet coloration with one part in 100,000 parts of solution 6 , and 
titanium trichloride, TiCl 3 , which gives a deep-violet coloration with 
one part in 20,000,000 parts of solution, the action resembling that of 
stannous c hlondc 7 

A colonmctnc test described by Pollard 8 depends on the production 
of a bright yellow coloration when a 1 per cent solution of o tolidme 
in hydroehloiio icicl of 10 per cent strength is added to a solution of 
auric chloiidc <oil HI _ one pait oi gold in 1,000,000 parts of water 
Osnuo ic id \ in id it (s, and s ilts of ruthenium and of iron also give a 
yellow color ition ind in presence of copper i green coloration may be 
obt line el mste wl of <i pine yellow colour Other metals do not interfere 
with the test bul 1 1 H < s <>l hypoe hlorite s give i gnss gieen oe>lor ition 

A nuthoel oi ele tee lion by me ins of the metiphosphite be id has 
ilso bee u (le se nhe el 

One t< n\ \\ e>f i nwiogriiri e>( gold ( ln ^ K detccteel by Biyei's micro 
ehenue il method mentioned m eoimcxmn \vith iiihielium (p 199) ind 
cesium (]) 210) 

(iolel is (stnniteel eju uitit itively by methods simil u to those em 
ployeelm ilsepi iht ilive ele tee tion Item he pieeipit iteelwith i stimUid 
solution of (me)iis snl])hite e>i pe>1 issium e)\i!ile 10 inel tlie excess 
est united by litiilion uilh pe nn ing in ite , oi ]>te ei])it ited with st 111- 
nous e hle)iiele in ilk ihne soluliem the e xee ss ol tin being ise e 1 1 line d by 
1ih ilion \vilh ie>ehne !1 Othei methoels ire einect tilr it ion with stannous 

1 I<ns(Mius /jtilwh anal ( 1 han ISM 25 200 

KIKM \<nitf<l and M>lu ho 100235 {O r > r > 
J Compan l^n^otti /nlvh anal Chan 1S70 9 127 
1 I ai mi lhnt/l<rt 1 oli/t<ch / 1K ( ^ 284 17 

emnpiK ( liiHsni M<l/i(Hl( u dn analyhschcn GUemie Hiunswicl 1 ( )01 r 2 J ( ) 
" Airnuu and lUrhoni /M/vr// Chon Ind JkolluitU 1010 6 290 

7 SUhliraml Harhran li<r 1011 44 JO(M) 

8 Pollard Avali/vt 10 1<) 44 94 

9 Donau /n/sr// (htm Ind Rollout 1008 2 273 

10 Jrinc<schi Apothrk Jnt 1804 9 121 

11 Franceschi Zufach anorg Chem 1892 i 238 



358 OXYGEN WITH A2OTE 

be obtained by lepeated distillations of any 
acid above 1 42 , provided there is a sufficient 
quantity of that, and the first products always 
taken What the (^languishing properties of 
this acid rray be, I have not had an opportunity 
of investigating 

4 The acid which consists of 1 atom of 
acid apd 2 of water, is possessed of striking 
peculiarities It is in fact that which consti- 
tutes a complete reciprocal saturation of the 
two elements Evaporation produces no 
change m its constitution , it distills as water, 
or any other simple liquid does, without any 
alteration It a< quires the temperature 248* 
at boiling which is greater than nny oJher 
compound of the two elements acquires At 
any strength above thas, the acid is most copi- 
ously elevated by heat , at any strength below, 
the water is most easily raised Pure water 
boils at 212 , pure acid perhaps at 30 , the 
union ot both produces a heavier atom than 
either, and requires a higher tenipeiature for 
ebullition , but in proportion a*> <e>ther prin- 
ciple prevails more than is necessary for satu- 
ration, then the temperature at ebullition is 
reduced towards that of the pure element it- 
self Proust has observed that nitric acid of 
1 48, produces no mo r e effervescence with tin 
than with sand , whereas the lower acids act 



NAME INDEX 



ABEGG, 6 31 39, 54, 60, 61, 85, 87, 88, 
94, 96 97, 102 113 155, 189, 190, 
193 201, 205, 259, 261, 307, 308, 31* 
315, 320, 335 336, 337, 348 

Abraham, 324 

Abram, 72 197, 208 

Ackworth, 254 

Adams, 281 

Addicks, 249 

Adhicary, 230, 231 

Adolph, 98 

Agamennone, 39 

Albrecht, 59, 60, 63, 64, 92, 100, 160, 191, 
192, 19 * 203 201 

Aldndge, 277 

Alexeeff, 224 

Alfa, 193 196 

Allen, 286, 332 

Allen A H 352 

Allen, H 8 M 

Allen 1), 201 

Allen T , 2(>H 

Allmind 27(> 

Alluarcl 221 

Aloy, 6 * 

Alsgaard 150 

Altmaycr 21 2(> 

Alvisi 21 S 219 

Amadou 171 

Amaj^at 1 (> 

Amat 74 1 \1 1 t r > 

Amb( i#< r 22 

Amm< iMiull* i I0( 

Aininon 148 

Amp( 10 45 211 

Anderson 27 509 

Andn 2 JS 2o(> 

Andmc 95 % MS IN I(>2 !(>(> 171 
179 ISO 280 2SI 

Aridiu 285 

Andieoh 12(> 

Arid i ( vv 22 

Andi( \vs (>2 

An^li 251 51 r > 

Angdum 2 JS 

Ans d 121 I i8 1 i9 17 > 220 22 i 

AmOdl 1H 

Antony 27S J i9 H7 

Apj)lcUy 7i <M 102 10 i 119 1 T> 1(>2 
174 180 192 19) 20 1 207 209 277 
287 

Aibusoff 117 

Archibald 120 157 158 l r >9 100 202 203, 
204 208 

VOL If 



Arfvedson, 52, 56 

Armani 320, 351 

Armstrong, 254 

Arndt, 94, 118, 120, 144, 161, 183, 231 

Anrn, 240 

Arppe, 226 

Arrhemus, 61, 68, 93, 96, 97, 111, 112, 120. 

136, 137, 140, 215, 216 
Arsdale, 248 
Arth, 234 
Aizaher, 175 
Ashcroft, 83, 161 
Aston, F W 32, 33 
Aston, Miss Emily, 89, 218 
Atterberg 149, 186, 241 
Aubert, 281 
Aueibacb 6 39 60, 88, 142, 182, 190, 259 

261 308 313, 331 335, 336 348 
Auger, 287 
Augustm 19 
Aveikieff, 328 331 
Avcry 342 
Aviccnna 211 
Avogadro 45 

B\AT Miss de 75 98 180 1S2 234 274 

28i m 
Bihoiovsky ill 
Jtachn von 25 } 
Hachran 351 
Biuovtseu 289 
Pidischo Anilin und Sodi 1* ibnl 107 

222 

R u y< i von }\ \ 
lia^i ilion I'nnc* )2 I 

Bj,s1<i - r> ^ 

IJulh 12 

I'un IS{ 

Pnl M 1 W 211 215 

llnlud H4 

H ilnn IT, 140 181 197 518 

Hal hi uio 27 i 

Ball 72 151 197 199 208 210 

Ballanf <) 212 

PilluiL, J52 

Udy 24 H J2 

11 SJ 107 

M 15 
Bancroft 295 W 
Bandiowsky 120 
Bancrjee 1 54 
Baibion 311 
Baiboni 320 351 

1% 

23 



360 OXYGEN WITH AZOTE 

5 The acid composed of 1 to 3 water, ha* 
not any peculiarity yet discovered. 

6 The acid of 1 to 4? water, is remarkable 
for being that which freezes the most easily of 
all, namely at 2 of Fahrenheit, according 
to Cavendish* The strength of the acid is 
such, as that 1000 parts dissolve 418 of marble 
Now, 418 of marble contain 228 of lime, and 
these require 370 or 380 of nitric acid, which 
therefore agrees with the acid of 1 to 4 water, 
and with that only Above that strength, or 
below, the acid requires a greater cold to 
freeze it The inferior acids appear to have 
no remarkable differences, except such as the 
table shews , but the temperature of freezing 
descends to some undetermined point, and then 
ascends again 

7 The notion of those who consider the 
intensity of acid solutions to be proportionate 
to the quantity per cent of the acid, or to their 
density, seems incorrect as far as nitric acid is 
to determine It is true, the auditv or sou?- 
?iess of the solution, the power to produce ef- 
fervescence with carbonates, and perhaps 
other properties, increase nearly as the quan- 
tity or strength , but the freezing and boiling 
temperatures, the action on metak, as tin, 
&c have successive waves, and abrupt terrm 



NAME INDEX 



357 



Delachanal, 184 

Delacroix 286 

Delepine, 224 

Demolis, 96, 111 

Denied, 262, 265, 288 

Dennis, 71, 131, 177, 178, 197, 202, 208 

Derome 78 

Dervin, 319 

Descamps, 349 

Desch, 116 

Desfosses, 340 

Despretz, 34 

Deutsche Gold und Silber Scheideanstalt 

vorm Roessler, 150 
Deventer, van, 253, 273 
Deville, 15, 20, 83, 216, 217, 238, 239 
Dewar, 10, 16, 17, 19, 20, 24, 84, 85, 123, 

139 145, 149, 214 
Dewey, 332 
Dexheimer, 267 
Diacon, 284 

Dibbits, 146, 184, 212, 239 
Dickinson, 119 
Diehl, 56 
Diemer, 337 342 
Di&iert 125 
Diesselhorst 97 
Dietenci 96 111, J 30 
Dingwall 167 
Dioscondcs 81 
Ditte, 92 106 H r >, 100 109, 219 234, 

275 **2, 340 U7 
Dittmar 40 44 50 00 08 2% 
Dittnch 1 *2 
Divcis H2, 1M I7S 222 220 234 238, 

259 2 r >4 \\ r > 
Uixon 24 12 r > 
Dobiosscrdow O r > 
Doeltci 94 
Doeiimkd *2<) 
Doiiunik 17 4 
Donith 17S 221 J20 
Doiidii L><> J r >l 
Donnan 72 2<)1 
Donny Si 
Douglas 217 
Dover 02 
l)r<s(l in 
DiiuUu S7 
Dulxus l r >() 
Dubovil/ I \ > 
Duhnuil I ><) 2<)<> 
I>u(dli</ 2 r ) ( > 201 
Dudoux 201 
l)udl(> r )i M M2 
Dutiu uhid MS Ul {17 
Dufd <)> 12 > I }S I 10 I II I 12 2l> 2S> 
Diiilour I<>7 
DiiMoa 20<> 
Dukdski lt<) I si. 

Dulon^ l<) 10 17 40 H i IS 2 >7 
Dumas T> \1 iS 10 II 10 4S S<) 2 >7 

2<)J 2 ( )h 2<) ( ) UO JIS 
DinimdilT 287 
Dunuyti b4 189 
Uuput 178 



Dussaut, 104 

Dutoit, 62, 100, 102, 218, 283 

Duvieusart, 115 

Dyk, van, 296 

Dykes, 328 

Dyson, 240 

EAKLE 219 

Early, 232 

Eastlack, 216 

Ebler, 277, 289, 351 

Eccles, 167 

Eckardt, 188, 189, 200, 201, 317 

Eder, 216, 217, 307 

Edgar, A , 254 

Edgar C , 22 

Edgar k G , 49 50, 51 

Edgar G , 25 

Edwards, 13 

Eggelmg, 126 191, 196, 207, 208, 314 

Ehrenberg, 329 

Ehrenfeld, 116 

Ehrenhaft, 252 

Ehrhch, 113 

Eissler, 322 

Elbs, 121 127, 176 225 

Elektroohenusche Weike, Beilm, 232 

Mkmgton 249 

Elster 91, 94, 154, 159, 189 191, 201 203 

Klten, 279 

JEnuoh, 24 199, 210 

Lmmerkng 224 

knde 62 

> udell, 07 77 78 206 

Fingel 234 280 285 

l^ngelhardt, 103, 100 

Imgler 84 

Pphraim 58 71 ( H 159 1U1 203 343,344 

\* pplc 145 

ln<knbicch( i 148 

Indrminn, H 2 188 189 193 194 200 

202 

iMdminn () 1 i5 J7 38 44 257 275 
|i|lwun J24 U> i20 
liinst Miss Use 27 r > 
iMdior 18 
l^spil 270 28 J 

1'tard <)S 1 JO 177 1 90 20 ( ) 281 
iMilu 07 
l<uiuoifo|)()iih)s (>() (>} (><) 71) ( )1 <)S 100 

IIS 111 l(>l l(>2 I7t IS} 
1 v uis Miss ( <li I I >-4 
l<vnns k l< IK) 
I'ydi VIM 17<) JI7 
1^ y<liu inn 2 ( )() 

I \ it i i 12 > 

I alir< 70 I2) 177 227 270 
l'biy i2 
I uiltv 2iJ 
laltoi 12) 
I ikiol i 2SS 
lnik 24 

J'atulay i2 55 329 

luibeufabiiken voimals luicdi Bayei and 
Co 108 



562 OXYGEN WITH AZOTE 

tenng with the air, (except the steam which 
gases commonly have, the quantity of which is 
fasilv ascertained for any ttrnperature) The 
jnstant the two gases were mixed, the globe 
was filled with dense oiange coloured gas, 
which continued without any change , a dewy 
appearance on the inside of the glass was al- 
ways perceived, consisting, no doubt, of con- 
densed acid and water 

The results of the experiments are below 

oxygen nitious gas pei cent 

1 l measure took 1 8, residuary 13 6 oxyg 



The residuary gas was examined after letting 
in water, and washing away the acid From 
these results, it is evident the quantity of ni- 
trous gas combining with a given volume of 
oxygen in such circumstances, is extremely 
variable, and much like what takes place in 
small quantities in tubes The colouicd gns 



2 11 


6 nitrous 


1 44 


- 27 oxyg 


1 83 


4 


229 


2 5 nitrous 


1 61 


7 6 oxyg 


1 65 


* 9 3 nitrous 


1 8 


2 5 oxyg 



NAME INDEX 



359 



Gibbs, 344 

Gibson, 108 

Giersten, 82 

Giesel, 94 

Gin, 248, 279 

Girard, 219 

Girsewald 186 

Gladstone, 26 

Glaser 250, 268, 311 

Glauber, 117, 211 

Gleditsch, Mile , 55, 56 

Gluud, 269, 279 

Gmelm, 35, 52, 56, 85, 106, 116, 117, 215, 

219 273 274, 277, 281, 297, 328, 330, 

333, 337, 338, 344, 345, 346, 347, 348 
Goadby, 139 
Godby 117 

Godeffroy, 188, 190, 202 
Goeoke, 331 
Gopner, 292 
Goerges, 72 
Goldbaum, 90 91 
Goldhammer, 19 
Goldstein 94 
Gold und Silber Scheideanstalt vormals 

Rossler 131 
Gooch, 79 289, 521 
Goodson, 102 205 
Goodwin, 97 
Gorce, 296 
Gordon, 97 
Gore 302 
Gorgeu, 98 
Gonanoff 25 
Gorke 240 
Gorski von r >J <>2 
Gossnci 120, 22 r >, 240 
Goudnaan 244 
Gowland 242 24 1 
Orabau 8J 
(Jracbt, 104 
(hafi I8S 200 201 
Giahani ) ( M7 
(jliaham Olio HJ HI HH 
Grahun I 20 2! 2i 110 2M 2hJ 

2S4 

(iiau^ r 270 275 2S > MS 510 
(,iay H \\ >0 
Ciay 1 A 2><) 
( ( K( M\\oo(l 1 2 r >0 20 > 
< m i 128 12') 
( K^oi \ $20 
Ones 210 
Ciiftitlis S> ISl 
( !<>,( i 2(>7 
Unxndahl 2 {I 

Giosdinfl ISO 2IS 2tl 2 >! 2)7 
(jiiossm mil 21 { 2S7 
Uioth 107 210 
Uiotiian 07 
Grouven 222 
Gnmcisrn IS 120 
Giunwald UO Ml 
Guareschj ( > i <)S ( ) f ) 10 } 1(>1 102 201 

216 281 K)5, 300 
Gunsburg 210 



Guertler, 20 54, 84, 148, 153, 189, 200, 250, 

272, 288 293, 331 
Guinchant, 316 
Guntz 53, 54, 58, 60, 62, 63, 68, 71, 75, 

85, 92, 93, 154, 160, 189, 200, 213, 
, 267, 270, 284, 302 304, 311 
Gupta, 346 
Gutbier, 21 22, 252, 295, 329, 338, 341, 

345, 347 

Guthne, 98 125 216 
Gutmann, 115, 126, 127, 215 
Gutzkow, 326 
Guyard, 217, 219 
Guye, 16, 47, 50, 51, 104, 299, 300, 301 

HAAOKB, 78 

Haase, 339 

Haas Oettel 103 

Haber, 25, 55 85, 87 97, 248, 249 

Habermann, 147, 256, 278 

Haohmeister, 60 214 262 

Haokspill, 2, 3, 52, 85, 86, 136, 153, 154 

181, 188, 189, 197, 200, 201, 285, 318 
Haen, 289 
Haga 132 

Hagen, E B , 84, 86 
Hagen R , 56 
Hagenacker, 21, 23, 294 
fT _ . i 253 
Hann 154, 189, 201 296 
Haigh 60 72 94, 95 134, 161, 179, 191, 

192 197 203, 208, 214 232, 233 
Hamsworth 272 
Hall 32 138, 314 
Halla 22 

Halle *24, 325, 326 
Halwkc 15 248 
Hambiugoi 102 193 205 
Kimmick H9 
Ham pc 250 257 258 284 
Hampshire 124 
Hann JO 

Hiusui A von 147 184 1 ( )8 
HuiMui ( J 84 15* 29 i 
H msoii 251 

II intsch 1 J2 255 250 J15 317 
H inns 28 ( ) 
II (KOI. it 10S 
llaidm^ 2S(> 
liaise uts ( )7 118 
Hu kins i2 M 
llii|)d 250 
Haiti L><) 

II iril< y 7J 115 III) 
llaitmum 1\ iO ( ) 
llaitoj, IK) 222 
llulmiK $01 105 {07 iO<) 
II ntw ip;nt i \2 { ) 
Ilissdifial/ 1 1 ( > 
11 nu nsUin 121 
llausknocht 272 
Hausrath Ob 

Hautcfcuillo 22 58 77 02 Io9 215 
Hauy, 228 
Hiwloy 280 
1 1 iyca $ J 



364 OXYGEN WITH AZOTh 

different qualities at different periods of the de- 
composition By one experiment, I obtained 
about 30 grains of air from 100 of nitre in an 
iron retort , it was received in 5 portions the 
first contained 70 per cent of oxygen, agree- 
ing with the constitution of nitrrc acid exhi- 
bited in the table, page 331 , but the suc- 
ceeding portions gradually fell off, and the last 
contained only 50 per cent oxygen 

It may be proper to remark, that the nitric 
acid of commerce is sold under the names of 
double and single aqua foitis , the former is 
intended to be twice the strength of the latter, 
the absolute strength of double aqua fortis is 
not, I believe, uniform It commonly runs 
between the specific gravities of 1 ^ and 1 4 



4 Oxijmtnc Acid 

The existence of oxymtnc acid is inferred 
from the combination of oxygen and nitrous 
gas, in the second experiment, page 328 , at 
least an acid product is obtained, containing 
more oxygen than is found in nitric acid As 
yet I have not been able to obtain this acid 
any other way, and therefoie have not had an 



NAME INDEX 



361 



Jaeger, 73, 78, 135, 148, 160, 162, 163, 164, 

179, 197, 209, 317 
Janeoke 223 225, 301, 316 
Jahn, 61, 87, 96, 97 100, 102, 104, 106, 

120 

Jakowkin, 102 
Jamieson 208, 289, 315 
Jaubert, 14 15, 108, 150 159 
Javal, 334 
Jawein, 141 
Jean, 92 
Jeffery, 133 
Jellinek, E , 127 128 
Jelhnek, K , 127, 128 
Jerdan, 26 
Jessup, A G , 8 
Jessup, A E , 8 
Joanms, 85, 97 131, 137, 147 148, 154, 170, 

181, 185, 240, 272 
Jorgensen 274 

Johannsen 53, 84, 153, 189, 200 
Johnson E S , 256 
Johnson, G S , 40, 217 
Johnson, L C 46 
Johnson, fe W , 201 225 
Johnston, 345 346 
Johnston J, 112 
Johnston, S M , 08 70 100 
Jolv, 138 140, 142 
Jones, 1 29 

Jones G 50 c )7 100 102 JOS 30 ( ) JU 
Jones, H I' 01 7J 90, 100 102 lib 
Jones, W A 202, 204 

Tonnson J 1 4 
Jorclis US IS") 2 r >2 
Joiisstu 1> 109 170 2*5 I 

Tone 97 
Joseph 2J2 

Toulc )4I 202 27$ 2S1 

Toulni 5 J19 

louni iu\ 2 >0 

Jovilsf hits< h 2 JO 
Juptiu i l r >- 

Juiniu 1 19 

JiiMchl < u i(s< }\ 2 1<) 

lusl 10 

K \MMI KI i K>s 

K ihlhuiin ~ l J >o J9 2'H itl 

kaliluilxu >' <>_ 7S S ' S7 9<> I9S J09 

K ilis< h< i L's 

K ilmim 1 {(> 

Kainin IS? 

k imp ( hult( 2 ( )() 

KJUI<|< i 22 I 

K UK iOJ 

K \i\\if 112 

K 41111 1 75 I > > li)D K)-* H>1 Hl 17 ( ) 

1<)7 MM) 
K 4>p<J< \ 2 is 
Ivui iiKhcll Ho 171 
Ivaistcn ( M 
Jvuwat 10 ( ) 
Kasinio\\ski ( )-l 
K as per 17 
kitUvmkd 22} 



Kaufler, 136 

Kaufmann, L , 12, 132, 315 

Kanfmann, P , 232, 233 

Kazanesky, 183 

Keiser, 35, 39, 40, 43, 44, 319 

Keith, 243 

KeUner, 103 

Kempf, 226 

Kendall, 30, 70, 121, 175, 215, 217, 223, 

225 

Kennck, 273 
Kenyon, 344 
Kern, 350 
Kerp 30 
Kessler 126 
Keyes, 91, 159 
Kiess, 295 
Kihani, 249 
Kimura, 295 
Kmgman, 196, 208 
Kmgzett, 232, 276 

Kirchhoff, 188 189, 198, 200, 207, 209 
Kirschner, 315 
Klaproth 82 
Klem 73, 136 
Klobb, 282 
Klooster, van, 78, 79, 118, 148, 149, 174 

182 186 

Kluss, 70, 222, 226 
Knaffl, 328 329 
Knecht, 128 226, 288 
Kmbbs 165 168 
Kmghtley, 130 
Knoevenagel 351 
Knopp 97 

Knorre von 141 230 
Knox 113 
Koch 304 W7, 309 
Kohohon Hi 
Konig, 182 
Koppon L ( )i 

Kothmi 2 18S 189 I'M JOO 
IvohliuiHth 55 87 <H 97 102 104 100 

111 120 1 JO 171 21i 2% 303 308 

JIO }}2 

KohlschutUi 278 290 293 295 
Kolm ( )7 
Koht HO ill 
Kollhofl 121- 

KullMMou Ml 

Konmc 1 d< h( ( ( oniii< k <k 

Konowiloll <)7 112 2S} 

Konsoit fin ( Ic 1 tioclu in liulusii Nxuu 

h( i rt SJ 
Kopp <) r ) 12 i 1U H ( ) 101 10(> IbS 174 

181 18 J 192 198 211 214 **9 
k(ipp( 1 2S2 
Kniit tOJ JO') 
k.iiiii^ 00 (>-J <J4 Ob K>1 K)J 192 202 

20 > 

koitwu^ht 13 > 
kouL 211 
kru-fft 84 15 1 
ki xlowansky 52 50 
kiinuhals, 1)7 
kiaus S5 



5 Nitwits Acid 

The compound denominated nitrous acrd, 
*$ obtained by impregnating liquid nitric acid 
with nitrous gas This acid, however, is 
never pure nitrous acid, hot a mixture of 
mtric and nitrous, as is evident by boiling it, 
when tfrfe nitrous is driven off, and the nitnc 
remains behind Pure nitrous acid seems to 
be obtained by impregnating water with oxy- 
genous gai, and then x\ ifh nitrous gas , in thtt 
way 1 measure of oxygen takes about S-| of 
nitrous , that is, 1 atom of oxygen takes 2 
atoms of nitrous gas to form 1 of nitrous 
acid The weight of the atom therefore 
rs 31 2 

By repeated trials I find that 10O measures 
of nitric acid of 1 30 specific gravity, agitated 
with nitrous gas, takes up about 20 times its 
bulk of the gas It the acid be of twice the 
strength, or of half the strength, a makes little 
difference , the quantity of gas is nearly as the 
real acid, within certain limits of specific gra- 
vity Very dilute acid (as 1 to 300 water) 
seems to have scarcely any power of absorbing 
nitrous gas, besides what the water itself has 
Hence, it seems that what we call nitrous acid, 



NAME INDEX 



363 



Lowel, 119 

Lowenherz, 105, 120, 121 

Loewenthal, 66, 106, 219 

Lowenthal, 29 

Lombard, 215, 216, 217 

Lome, de 234 

Long, 84, 154 

Longi, 106 

Loomis, 96, 111, 120 136, 140 

Lorenz, 134, 136, 153, 163, 179, 201, 306 

Lormg, 8 

Losamtch, 29 230 

Lessen, 319, 324 

Lottermoser, 252, 295 

Lougumine, 138, 139, 193 

Louis 325 

Lowndes, 230, 232 

Lowry, 8, 232, 296 

Lucas, 313 

Lucchesi, 278, 339 347 

Lucking, 287 319 

Lucke, 21 

Luhng 213 

Luppo Cramer, 305 

Luise, 52 

Lumiere, lib, 304, 300, 30b 

Luna, de, 215 

Lundstium, 73, 234 

Lunge 34 65, 143 253 

Lupton, 262 

Lussana 268 270 

Luther, 31 HI, 312 

Luynes 237 

Mo AD AM 145 
Macallan 129 
MacAithui, J24 
McBain 22 
McCombu 21 S 



Mcdao (>l 94 9S 100 1 IS |()2 10 J 174 

18 J 2SJ 
McTiosl y 205 
McDou^all 1S7 
Mc( <( 1 M 
Mac hatln 1 i 1 
M(Ilhmii(\ $21 
M( Johnson 21 ( ) 
Muk 105 
Mukin/n II 12n 127 17) I9(> 199 

20S 210 

M K k< n/H ) ) 97 
Mt I UK hi in 97 
M K 1 mi m 52 > 
Me 1 uman 20 2 > 
McLcod 10(> 1(>7 
Mukod Piown 2S1 
MocqiKi S iO 
Maddicll 111 2S ) 
I\Udoisk\ \2 
Madstn *11 

Magnus 1 lOh 2 >o 2 ( ) > in > ios 
Mailfcrt J10 
Mailhi 2% 
Maisch 21 
Majoi, 202 281 342 



Makowka, 271 

Malaqum, 225 

Malatesta, 320 

Mallard, 18, 24 

Mallet, 56, 335, 336 

Maltby 55, 97 136 

Manchot, 13, 262, 264, 265, 266, 271, 274, 

283,296 
Mangarim, 251 
Manuel, 215 
Marchal 133 

Marchand, 35, 37, 38, 44 223, 234, 257, 275 
Marchese 248 
Marchetti, 315 
Marden, 62 
Maresoa, 83 
Marggraf , 82 
Margottet, 77, 270 
Mangnac, 35, 36, 60, 87, 96, 100, 102, 106, 

120, 121, 136, 140, 155, 156, 157, 213, 

222 225, 297, 298, 302 
Maronneau 270 
Marsden, 31 
Marsh, 309 
Marshall F , 187 
Marshall, H , 126, 127, 175, 189 196, 199, 

208, 210, 225, 312 
Maitelheie, 222 
Mai tens, 95 
Martin 284, 352 
Masmg, 54 84, 153 
Mason 144 
Masson, 7, 31 
Mather 296 
Matheww 350 
Mathcwson 129 

Matignon 96, 133 142 143 240 311 
Mittti H5 

Matthusson 52 53 54, 85 
Miu 170 

Miumtm l r > r > 1% 219 221 298 
M luiichuiu -Bcaupic, 12 
M into 201 
M iwiow 277 521 
Mi\tl 2J IM 
Muyd M 21 20 
M>y<i W 80 
Mi//u((hdli IS5 
Mil>uig l()9 2U 219 271 
MulltH 1S7 
Vlunul ( J r > 297 JM 
MnntU 125 
M( issue i 5t 
Mul/didoiil 272 2b7 
M<ldiuin (>() 191 20 J 
MdilolT l r >0 220 
Mdsdis J7 40 

M<nd<ln 1 (> 7 J9 4(> 28 i HJ 
Mi IK ^hiin 1M Ml 
M<n<s i2i 
Mdilc 200 
Md<aduu HO 
Mdcl 121 147 
Mcngold 260 
Mtikcl 18 
Merlin, 71 80 



368 OXYGEN WITH CA&BONE 

combines with the alkalies so as to form dry 
salts or nitrites , the concentrated solutions 
seem to lose the nitrous gas, and then the ni- 
trates are obtained 



SECTION 3 



OXYGEN WITH CARBONE. 

There are two compounds of oxygen and 
carbone, both elastic fluids , the one goes by 
the name of cai borne acid, the other cai bonic 
oxide y and it appears by the most accurate 
analyses, that the oxygen in the former is just 
double what it is in the latter for a given 
weight of carbone Hence, we infer that one 
is a binary, and the other a ternary compound , 
but it must be enquired which of the two is 
the binary, before we can proceed according 
to system The weight of an atom of carbone 
or charcoal, has not yet been investigated 
Ot the two compounds, carbonic acid is that 
which has been longest known, and the pro- 
portion of its elements more generally investi- 
gated It consists of nearly 28 parts of char- 
coal by weight, united to 72 of oxygen No*v 



NAME INDEX 



365 



Netto, 153 

Neumann, B , 82, 109 

Neumann F , 214 

Neumann, G , 265 

Neumann, K , 268 

Neville 57 85 118, 174, 190, 250, 251, 293, 

331 

Newberry Vautm, 324 
Newlands, 7 
Niccolai, 251 
Nickles, 337, 342, 344 
Nicol, 120, 136 
Niementowsky, 133 
Niemeyer, 108 
Niggh, 77, 148, 183, 185 
Nilson, 70 
Nithaok, 25 232 
Nocentim 149 
Nola, 320 

Nordmeyor, 85, 16} 331 
Norns, 196, 208 
North, 332 
Novotny 109 
Noyes, A A , 96, 97, 1% 215, 271, 310, 

311 
Noyes, W Albert 40 4), 44, 50 51, 06, 

159, 300 
Noyes W Amos 40 

OBBRBECK, 295 

Oberkampf, * W HI 

Bnen 97 

Oddo 8 

Oechsli 105 

Oehlcr, 22(> 

Oholm f)l 

Oelkoi, 2*2 

Oottol 97 H>2 

Octtingcn \on 121 

Ogawa 222 22(> 



Olm 220 

Oliver 18J 

Olrncr {10 

Olmstuwl 7t 2J1 

Ols/ewsl i 1<) 

Ornodd SI S > 151 1 >t 

Ooidt \ in 2> 

()|)l(l< IMS \ )2 

Oppm inn III MS 

Oidwav 7S 1 ( )S 

OilolT 2S <)l I2S 

Oitloll 27S 

Osal a ')(> 

Osann 2 ( ) 

OHhonu 277 

O Shea 10 > 1(>S 2(>() 

Ost 222 2S2 

2s n r> {<> r < 

S(> 87 SH <) > 100 102 



1 0(> 11<) 120 12(> 1 U 1 ? 

2J<) -HO 

Oswald 72 I U 17S U > U<> 
Otm 70 
Ottenstom 22 



104 10 r > 
IS ( ) 21 ! 



Ouvrard, 74 
Overman, 281 

PAAL 22, 23, 26, 252, 267, 278, 295 

Paepe, 227 

Page, 136 

Paghani, 120 

Palas, 280 

Palfreeman, 165, 168 

Palitzsch, 294 

Palmaer, 30 

Palmer, Dorothy M , 28 

Palmer, W G , 28, 256 

PanfUoff, 101 

Pannam, 296 

Papaconstantmoii, 320 

Pape, 123 

Parkes, 289 

Parkman, 283 

Parmentier, 125 

Parravano, 113 

Partmgton, 22 

Pasoa, 120 

Pascal, 250 

Pasteur, 182, 237 

Patern6, 185, 302 

Patrick 281 

Patten, 53, 55, 62 

Patterson, 27 31 

Pawloff, 317 

Payelle 115 

Payen 149 

Poarce 100 

Pebal 166 

Pcchard 106,222 

Pechcux 260 

P61abon 312 H4 347, 348 

Polatan 326 

Polct H2 

VoliKot 278 

Pcllal 2% 

Pollotier H4 H7 340 

Vllicmi 314 

>ollmi HO 196 

Mou/c 89 155 234 

Miner 147 194 19S 

ondn6 2V) 

\nin\t\ i44 

> <nny H f ) 155 2 ( )S 

Nikin 120 

Nnnan % 

Viol 282 



t 15} 255 283 UJ 
U5 130 I } ( ) 17 ( ) 



285 



>ot(iH 
>tt(i4 



W UJ 254 ^0 

n 140 

n IMUI! 5<) 341 

}52 

*<ta 19 257 
Ntno 242 
\ ttcnkofci J27 
Pdtorsson 70 
Pfaundki 140 
Pfoidten von dci 12, 3 
Phihpp 318 



370 OXYGEN WITH 

electric shocks into oxygen and carbonic 
oxide , but carbonic oxide does not appear to 
be resolved m the same mode into charcoal 
and carbonic acid, which one might expect 
from a triple compound One of the most 
common ways of obtaining carbonic oxide, is 
to decompose carbonic acid by some substance 
possessing affinity for oxygen , now, oxygen 
may be abstracted from a body possessing two 
atoms of it more easily than from one posses- 
sing only one On all these accounts, there 
can scarcely be a doubt that carbonic oxide is 
a binary, and carbonic acid a ternary coin* 
pound 



1 Cm home Oxide 

This gas was discovered by Dr Pnestlfcy, 
but its clistmgu -iViig features were more fully 
pointed out by Mr Cruickbhanks, in an essay 
in Nicholson's Journal, 1801 About the 
same time, another essay ot Desormes and 
Clement was published in the Annales de 
Chemie, on the same subject These essays 
are both of great merit, and highly creditable 
to their authors Before that time, carbonic 
oxide had been confounded with the combus- 
P"KP<; composed of carbone and hydrogen a 



NAME INDEX 



367 



111, 119, 125, 138, 145, 153 157, 158, 
159, 163, 171, 189, 191, 200, 202 203, 
204, 208 216, 250, 256, 258 259, 260, 
266, 276, 293, 294, 296, 298, 299, 300, 
301, 313, 331 
Richter, 333 
Richter, E 329 

Riddle, 94, 98, 100 149, 174, 183 193, 204 
Rideal 28 

Rieke, 67 77, 78, 206 
Ries, 165, 168, 169, 219 
Riesenfeld E H , 77 97, 147, 170, 184, 

198, 209 

Riesenfeld, H 61, 97, 113 
Rissom, 131, 178, 197 208, 230 284, 314, 

339 

Ritthausen, 264 
Roberts, 267 275 
Robertson, 255 
Rochleder, 222 
Roczkowsky, 133 
Rodewald, 302 
Roehnch, 215 
Rohng, 69, 116, 117, 222 
Rontgen, 18 
Rossmg, 278, 279 
Rossler, 147 320 
Rogers, 37 
Rogojsky, 269 

Rohland, 104, 10 r > 120 214 217 
Rolla 284 
Roloff, 87 

Romanese 233 308 
Roozeboom 104 I7<) 210 217 t08 
Roscoo 122 
Rose MO 

Rose I* JOt 

Rose H 2M 2t r > 2JS 2 t<) 202 200 2(57 
208 270 27? 2SJ JS r > Ml JI4 J27 
t2S 

Rose Sn IK J2t J27 Jit U2 

Rosdifdd 2(>2 

Rnsdihaupl 2 r >2 

Rosenhdm 00 71 70 7<) 100 I JS I r >0 
177 ISO !<)<) 21<) 110 II J U<) 

Uosicly IIS I JO 

Rossem \ in JO J 

Roth 2( r >t (>() OJ 01 ( >0 <>7 2JI 212 
2><) 2<)t 2M1 JJ1 

Rnthdilndi l r >l ls<) 201 

Rothnnind 7<> ( )7 K>S M J 

Rothw<ll J2I 

Howi (>S III 171 

Rubinovitdi 270 2S~> 

RudclofT 2J2 

Rudolfi 272 

Rudolphi S7 

RudoilT S(> 201 JJ1 

Rucl (i 21 J 

Rudoifl 1H > 240 



Him ">i S(> 1 >4 201 212 2<r> JU 
Rufl r >J 72 S4 <)2 ( )t <)"> ( )S 100 IIS 

Jil l r >J 1()0 1()2 10 { 171 17S ISO 

10(> 200 20S 2U JJ1 
Rule 112 lit 114 ll r > 172 I7t 



Rupert, 220 

Rupp 217 

Ruppm, 120, 226 

Russell, 267 

Rutherford, 11, 32, 33, 34 56 

Rybalkim 262 

Rydberg, 53, 154, 188, 201, 294 

SABATIBE 27 28, 113, 114, 115 171, 172 
173, 221, 252, 256 267, 273, 274, 276 
281, 288 

Sacerdote 50 

Sacher, 112 

Sachs, 189, 302 

Sack, 55, 85 87 

Sackur 85, 313 

Sagher, 265, 266 267 

Saint GiUes, P de, 262 

Sala, 211 

Salet, 83 

Salkowsky or Salkowski, 237, 286, 316 342 

Salm, 138, 140 

Salvador! 218 239 

Salzbergwerk Neustassfurt, 170 

Salzer, 74, 138 236 

Sand 30, 169, 198 200, 249 

Sandmeyer, 265 271 

Sandonnmi 265 

Santi 215 

Santos 318 

Saporta, dc 289 

Sarma 267 

Sartori 213 

Sattoily 86 154 

Saundeis A P 96 120 136 

Saunders HI 232 

Sborgi 21-0 

Sc igliatim 277 

SciU 251 295 

Sc ilioni 25 

Scupi H7 

Sduulld 8t SI 

Sdudd 00 0* 94 95 101 102 177 

Nh illtfotsdi 1 J4 

Sdulld 97 



Sdi 
Sdi 

vS(h 

Sd 
Sdi 
Sdi 

Sdi 
Sd) 
Sd 



d IS 

di 2S5 J0"> JtS 

He i 1 JO 

dxi 271 

in JI7 

inlsc hushiiy (>() 02 94 9"> 

1(>1 102 191 192 20$ J01 



102 120 
JOJ }*<) 



I \\\L, J2 > 



no r >0 J01 

<l( tin 70 
Sdull 97 IIS 1 JO 

224 22) 2t2 2J 
Sdnflnci 244 
S< hil/ t25 

Sdnmpft 2 r >0 295 Ul 
Sdnndld 145 
Sddamp 55 (>2 100 102 
Schlcnl H2 
vSchlosscr 178 



Its 140 142 210 
2J(> 2 J ( ) 2SO 



372 0\\ GEN WITH CARBONE 

of this process is manifest , chalk consists of 
carbonic acid and lime , the carbonic acid 19 
disengaged by heat, and is immediately ex- 
posed to the red hot iron, which in that state 
has a strong affinity for oxygen , the carbonic 
acid parts with otle half of its oxygen to the 
irop, and the residue is carbonic oxide , but 
part of the acid escapes along with it unde- 
compounded With a proper apparatus, the 
gas may be procured by transmitting carbonic 
acid repeatedly over red hot charcoal in an iron 
or porcelain tube 

This gas may be obtained, by exposing to a 
red heat, a mixture of charcoal with the oxides 
of several metalb, or with carbonate of lime, 
barytes, &c But there is great danger in this 
way of procuring some hydrogen, and carbu- 
retted hydiogen, along with carbonic oxide 
and acid Indeed, all gas procured from 
wood and from moibt charcoal, is a mixture of 
these four, varying in proportion according to 
the heat and the continuance of the process 

According to Cruickbhanks, the specific 
gravity of carbonic oxide is 956 , according 
to Desormes and Clement, 924- Appre- 
hending that they had both rated it too low, 
I carefully found the specific gravity of a mix- 
ture of 6 parts carbonic oxide and 1 common 
*if at torn tnak m one it came out .945> 



NAME INDEX 



369 



Spriler, 347 

Spitzer, 178, 275, 277, 289 

Spring, 121, 122, 126, 195, 207, 226, 266, 

Stackelberg, 96 

Stadler, 138 

Stabler, 158, 300, 351 

Stahl, G E , 11 

Stahl, W , 251 

Stanek, 278 

Stanford, 273 

Stang Lund, 131, 178 

Stansbie, 254 

Stas, 35, 37, 38, 39, 44, 56, 87, 88, 89, 90, 

155, 156, 157, 214, 294, 297, 298, 299, 

313 

Stavenhagen 182, 285 
Stefan, 18, 95 
Steger, 278, 308, 309 
Stem, 60, 237 
Sterner, 97 

Stemhauser, 313, 314 
Steinschneider, 285 
Stemwehr, von, 93 
Stephan, 246 
Stern, 179 
Steubma, 330 
Steyer 23 

Stock, 149, 186, 261, 307 
Stoerok, 153 
Stoklasa, 26 

Stolba, 60 188 210,272 
Stoll6 132 

Stollenwerk 303, 307 309 
Stone 168 
Storbeck, 203 
Rtorch 87 

Stoituibekei 17~> 2S2 
Storz 268 
Stiaclim 27(> 
Sticckci S(> 1S2 IS 3 102 10 J 232 230 

237 240 
Stiong 1V1 ISO 
btmckmxnn 2 JO 
Stiu ti *2 
Stmv( 200 
Stubbs 2">1 
Stull 100 102 
Stuim 7S 
(Su<Iboioti^li Jl I 
Sule J12 
Siilm in 12 > 

SllllWK/ 100 

Suslmir, 3H 
hvulbutf 2)2 120 
Sv( nsson tl i 
S\v in 24 ( ) 2 )() 
SxviontJ mvsKv 277 

TABJ R 2SO 

Tan Ixi 147 

Tvtel 112 

Tammann 54 00 04 09 74 S4 8 ) <)2 
<)4 00 <)S 100, 104 100 111 118 120 
12> 120 m H6, 138 140 141 142 
144 140 15i, 101 102 16 J, 174 175 

VOL II 



183, 191, 195, 207, 308, 309, 342, 343, 
344, 345, 346 

Tananaeff, 294 

Tanatar, 119, 147, 150, 160, 312 

Tartar, 252 

Tarugi, 124 

Tauber, 222 

Taylor, Bdytha, 283 

Taylor, H S , 309 

Taylor, J , 125 

Taylor, S F , 136 

Taylor, W W , 123 

Teed, 167, 325 

Ter Gazanair, 299 

Terreil, 303 

Terres 24 

Teschenmacher, 238 

Teudt, 96, 120, 136 

Than, 215 

Thatcher, 126 

Thenard, 85, 107, 131, 152, 177, 277 

Theodor 289 

Thiel, 125, 309 320 

Thiele, 180, 226 

Thienemann, 86, 232 

Thillot, 141 

Thomas, J S , 112, 113, 114, 115 272 

Thomas N G , 73 

Thomas, P 288 

Thomas S G , 83 

Thompson 83, 152 342 

Thompson H V 148 

Thomson 38, 42 43 44 48, 68 69 88 92 
00 100 101, 103 104, 111 113 115, 
118 119 120 121 123,126 130 135, 
130 137 138 139, 140 141, 144, 162, 
103 164 165 166 168 169 171, 173, 
174 176, 179 183, 184 212 214 215, 
210 217 221 224 233 264 265 266, 
273 274 275 281 284 303, 306 311 
313, 310 328 334 337 340 341 

Thomson J M 237 

Thomson bn J J 31 32 

Thomson T 3~> 333 

Thoipc 2bO H~> 350 

Hum it 112 

1 huduluim 270 

Illumine! 2l(> 

lihbils MO 177 2SJ i!4 

riulo 300 

lildin 9 r > 1 50 142 10<> 174 ISO Isl 

lilhy 301 

Imiot&ff 1<> 

hnklu 20 

lithcrlcy 72 I Jl I J2 !7S 1% 

litoff 110 

htus 272 

Toblci 281 

Pooplor 41 

Tolinan 31 SO !">> 

Tombrock, 2S1 

Tomkinson I i(> 

Tornmasi 224 254 

Toporcbcu 144 

Topsoe, 126 227 27* 343 U4 

Torelli 277 

24 



374 OXYGFN WITH CARBONE 

100 measures of carbonic oxide are mixed 
with 250 of common air, (in which case the 
whole of the combustible gas should combine 
with the whole of the oxygen) a smart explo- 
sion ensues by the first spark , but only -d& of 
the gas is. burnt ., the rest, and a corresponding 
proportion of oxygen, remain in the residuum* 
^\hen plenty of combustible gas and a mini- 
mum of oxygen are exploded, the whole of 
the oxygen usually disappears 

Carbonic o\ide does not explode by elec- 
tricity when mixed with oxymunatic acid, at 
least in any instance I hive had, unless i small 
portion of common air be present , but the 
mixture being exposed to the sun, a diminution 
syon takes phce, if tie light be powerful, 5 
or 10 minutes are sufficient to convert 100 
grain measures of the gas along with 100 of 
the acid, into carbonic and muriatic acids I 
have n< t been able to determine, from the 
lateness of the season (October), uhcthcrthe 
mixture w'ould explode b) thcsolai light 

Pure carbonic o\ide is not at all aflcctcd by 
electricity I was present when Dr Henry 
conducted an experiment, in which 35 mea- 
sures of carbonic oxide received 1 100 small 
shocks , no change of dimensions took place , 
there was no carbonic acid formed, nor oxy- 



NAME INDEX 



371 



Werner, 8, 31, 240, 263 

West Deutsche Thomasphosphatwerke, 25 

Wheeler, 65, 192, 193, 204, 205, 217, 344 

Whipple, 254, 316, 325, 332 

Whitby, 320, 321 

White, 152 

Whitehead, 352 

Wickel, 153 

Wiedemann, 94, 251 

Wien, 4, 250, 331 

Wiesler, 141, 285 

Wilke Dorfurt, 173, 194, 206 

Will, 213 

Willard, 56, 57, 66, 301 

Williams, 84, 105, 153, 168, 169, 198, 203, 

263, 265, 266 
Willigen, 112 

Willstatter, 27 121, 124, 126, 224 
Wilsmore, 31, 87 
Wilson, 32 
Windisch, 289 
Wmkelblech, 268 
Wmkelmann, 21, 85, 96, 97 
Wmkler, 53, 83, 329 350 
Wmteler, 105 
Wisucenus, 12, 1S1 
Witt, 182 
Wittjen, 94 
Wittstem 104 346 
Wohler F 152 253 262, 271, 311 
Wohler, L 94 131 178 275, 276 302 315 
Wohlwill, 327 344 
Wolcott 166 
Wolensky, 177 
Wolesensky 131 2?7 
\\olf 29^ 



Wolff, L , 303 
Wolff, S , 86 
Wolffensteni, 112, 147 
Wolfrum, 222 
Wollaston, 34, 45, 257 
Wolokitm, 186 
Woltereck, 223 
Wolters, 92, 94, 118 
Wonfor, 218^ 
Wroblewsky, 16 
Wulf, 31 

Wurtz, 235 261, 285 
Wyckoff, 202, 204 
Wyrouboff, 118, 224, 226 

YAMAUOHI, 124 
Yorke, 339 
Young, 25 
Young, S , 215 
Young, S W , 123 

ZALESKI, 187 
Zannmovich Tessarm, 62 
Zasedatelev, 336 
Zawidski, von, 142 
Zdobnick^, 26 
Zehnder, 131 
Zeise, 240 
Zenghelis, 29 108 
Zenker 304 
Zepermok, 120 
Zimpel, 222 
Zmoke 256 
2itek, 136 
Zorn, 178 
/sigmondy, 329 330 



24* 



376 OXYGEK WITH CARBONE 

Cruickshanks certainly underrates the oxy- 
gen , I always find the oxygen fully equal to 
half the carbonic acid, whether fired over mer- 
cury or water Desofmes' experiments wtre 
made over water, and are therefore rather un- 
certain ?is to the quantity of acid , they have 
evidently used impure gas Their first result 
given above is the mean of nine experiments , 
the other two are extremes in regard to acid 
and oxygen (Annales de Chimic 39 page 38) 
It is remarkable, that in one of their deduc- 
tions (page 44), on which they seem to rely 
most, they find the carbone 44, and the oxy- 
gen 56 parts by a previous experiment, they 
had found carbonic acid to- consist of 28 1 car- 
bone, and 71,9 oxygen (page 41) , that is, of 
4* carbone, and 112 oxygen where the oxy- 
gen is jubt double of that m the carbonic oxide 
to a given quantity of carbone This most 
striking circumstance seems to have wholly 
escaped their notice 

The exact composition of this gas is easily 
ascertained by exploding it with common air 
over water Let 2 parts of the gas be mixed 
with 5 of air, and fired , the residuum must 
be washed in lime water, and the quantity left 
accurately noted , then apply a small portion 
of nitrous gas to the residuum, sufficient to take 
hence we have data to find 



SUBJECT INDEX 



373 



Auric sulphate, 347 

sulphide, 347 

tellunde, 348 
Aunbromic acid, 345 
Aunchlonc acid, 343 
Auricyamc acid, 350 
Auri lodic acid, 346 

Aurous ammomo derivatives, 338 

bromide, 337 

chloride, 336 

cyanide, 339 

fluoride, 336 

hydrazoate, 339 

iodide, 337 

ion, 332 

oxide, 338 

sulphide, 338 

sulphite, 339 

thiosulphate, 339 
Auryl sulphate, 347 
Autumte, 65 
Azunte, 242, 287 

BEAN SHOT coppei, 247 
JBerzehanite, 270 
Black metal, 245 
Blodite, 81 
Blue metal, 244 
Borax 149 
Boinite, 242 
Boss process, 291 
Brochantite, 281 



fc, 208 

Caesium See Ghaptei V II 

atomic weight, 201 

chemical piopeities 201 

detection 210 

estimation 210 

history, 200 

ion, 201 

occunenct 200 
physical piopeities 2 200 
piepaiation 200 

VV itei on, J 
( i sium uuibiomidt A) 

biomld< 204 

cubidi 20<) 

en boil lie 20 ( ) 

< hloi it< 205 

(blonde 203 

<lioKid< 20(> 

disulplndt 20<> 

dithionate 208 

iluoiKhs 20,3 

hyth i/o lie 20S 

hydiich 203 
- hyclr<>^( n c ubon ih 2() ( ) 

sc It mitt 208 

sulphate 207 

hydioxidc 200 

indatc 205 

iodide 204 

mctasilicdto 20^ 

monosulphide 200 

niono\ide, 205 



Caesium nitrate, 208 

nitrite, 208 

pentasulphide, 207 

percarbonate, 209 

periodate, 205 

peroxides 205 

persulphate 207 

phosphates, 209 

phosphide, 209 

polyhalides, 204 

pyrosulphate, 207 

selenate, 208 

suboxide, 205 

sulphate, 207 

sulphide, 206 

sulphite, 207 

tetrasulphide, 207 

tetrathionate, 208 

teti oxide, 206 

thiosulphate, 207 

tnoxide 206 

tnthionate, 208 
Calavente, 322 
Caliche, 134 
Carnalhte, 152, 160 
Carnotite, 55 
Cassms, Purple of, 330 
Cazo process, 291 
Cement copper, 248 
Chalcocite, 242 268 
Chalcolyte, 55 
Chalcopynte, 242 
Chessyhte 242 

Chile saltpetre, 81 
Chrysocolla, 242 
Coaise coppei, 244 
Cobaltous auncyamde, 350 
Coppei See Chaptei IX 

implications 257 

atomic weight 257 

autoxidation 250 
catalysis 250 

chemical piopeities 2^2 
cupollition 293 
detection, 288 
diy it. lining 24(> 
dcttiolytu deposition >0 
- ichning 2J-*) 
( lectiomct ailing^ 2 IS 
histoiy 212 
I ions 2)5 

occlusion 2oJ 
occiuicuce, 21J 
01 os 242 

physic \i j>io])( ititb i 2)0 
pupaiation 244-2 J-') 
K fining 24 ( ) 
liciiLsmutilion r > > 87 
\altiu y 25 > 

( oppc i Ac< Cupiic Cuptous 
- Hedii shot 247 

Bhstei 24 r > 
- C ement , 24b 

Coaise 244 

Colloidal 250 

1'eathtieel sh t, i/ 



378 OXVGEN WITH CAfcfiONE 



2. Carbonic Acid 

The gas now denominated carbonic acid, 
has been recognised as an elastic fluid distinct 
from atmospherical air, for a longer time per- 
haps than any other It may be said to have 

gases that have been considered as belonging to these two 
species, are in fact oxjcarbuietted hydrogen , and thtt 
these elements are combined in an indefinite vinery of pro- 
portions That the combustible gases produced from moist 
charcoal and other bodies, contain oxygen, caibone, and 
hydrogen m vauous piopoitions, is a fact of which no ex- 
penenced peison can doubt , but it has not yet been 
shewn salufactonly by any one, that tiiej cannot be mide 
by mixing certain proportions of two cr more of the fol- 
lowing distinct species namely, cmburcttcd hydrogen (of 
stagnant watei ), carbonic ondc, okfiant gas, and hydrogen 
As foi caibomc oxide, whilst it remains in mdisputed 
fact, that in the combustion of it iiothing but carbonic acid is 
pioduced, and that equal in weight to the carbonic oxide 
and the oxygen, it will teqmie \cry specious reasoning to 
commce -my nne that it contains either hydrogen, sulphur, 
or phosphorus , unless it be first proved that carbonic acid 
contains the s-\mc One argument of Berthofla u>, ho\\ 
ever, more ingenious than any replv to it which has ap 
peared it n this, a compound elastic jluid ought to be found 
specifically heavier than the lighter of the tuo elementary 
fluid* constituting it This is, as far as I know, unueisally 
true , but it dues not follow that carbonic oxide should be 
h< avier than oxygenous gas. An atom of char- 



SUBJECT INDEX 



375 



Gold See Auric, Aurous 

alloys 336 

arsenides 349 

carbide, 350 

dibromide, 341 

dichlonde, 340 

monosulphate, 341 

monosulphide 341 

monoxide 341 

nitride, 341 

sesquiphosphide, 349 

Silicon and, 350 
Golden fleece, 322 

HESSITE, 290, 322 
Horn silver, 290 
Horse flesh ore, 242 
Hydrogen See Chaptei II 

atomic weight, 34 

chemical propel ties, 24 

detection, 34 

diffusion, 20 

estimation, 34 

expansion, 16 

history, 1 1 

ion 30 

liquefaction, 19 

manufacture 13 

Nascent, 28 

occlusion, 20 

occunence 10 

- Palladium and 21-23 

physical pioperties, Ib 

position in periodic table b-8 

- - prepaiation 1 1 
- Piessuie on 17 

reducing activity JO 

solidification 20 

Iiiatomic 28 
Hycliogomtr l r > 
Hydiohtc 14 

INIUOO coppc i 242 27H 
lion Sto un on 15 
Isomoiphism i if sulphites 22b 
isotopes JJ 

Ivii si i in 117 
KINO pmetbs 292 
Knxhnkito 282 
Ivnmko pioeoss 201 



v N ( 1 1 1 2 S 1 
mltnlliU 211 

( I>1 UK pMH ( SS 1 1 > 

( pidoljt< r >2 
( iu itt 1 r )2 
ithamuh 71 
ithn inic i r )2 
ilhiuUs Amnioiio 241 
ithiuin Acr Chiptti 111 
- ilomic weight % 
( hcnuc d piopcities j4 

detection 79 

estimation, 79 

histoiy, 52 



Lithium ion, 54 

molecular weight, 57 

occurrence, 52 

physical properties, 2, 53 

position in periodic table, 57 

preparation 52 

transmutation, 54 

LITHIUM acid silicate, 77 

antimonate, 75 

antimonide, 75 

arsenate 75 

arsenide, 74 

borate, 79* 

bromate, 66 

bromide 63 

carbide 75 

carbonate, 76 

chlorate 65 

chloride, 60 

chromate 70 

cyanide, 77 

dichromate, 71 

dihydrogen phosphate, 74 

dithionate, 70 

fluonde, 59 

hydrazoate, 7 1 

hydride, 58 

hydiogen sulphate, 70 

hydiosulphide, 68 

hy dioxide 67 

hypochlonte b5 

innde, 72 
lodate 66 

iodide 64 

- meti arsenite 75 
nictaborate 70 

met iphosphate 74 

- metasilicate 77 

- inolybdatts 71 

- inouosulphidt 68 
monoxide bb 

- nitictte 72 
nitiide 71 
mtnto 72 
oithophosphatc 74 
oithosihcate 77 

p( ic nboni(( 77 
pcjchloiatt bb 
pciioditt bb 
pciniuiguiili 71 

- [KlOXUlc (>7 

})( isulj)hdto 70 
pliosphuk 7 1 
p h os phomoly hclnlcs 71 
poly boi ate 70 
polysulphidcs (>0 
-stlenitt 70 

- se Icnidc 70 
-~ sckmte 70 

silicate 77 

silicidc, 77 

subcliloxidc (> j 

subsihc itc 77 

tsulphate, b9 

sulphite, b9 



380 0\\Gtt \\IfH CAOONC 

Carbonic acid gas is formed by burning char* 
coal , but it is most easily obtained in a pure 
state from chalk, or some of the carbonates, 
by means of dilute sulphuric or other acid , it 
may be received in bottles over mercury or 
water, but the latter absorbs a portion This 
gas extinguishes flame, and is unfit for respira- 
tion , its specific gravity is nearly 1 57, as ap- 
pears from the experience of all who have 
tried 100 cubic inches, at the pressure of 30 
inches of mercury, and temperature of 60% 
weigh from 47 to 48 grains Carbonic acid is 
frequently pioduced in mines, and in deep 
wells it is known to workmen by the name 
of choak damp, and proves fatal to many of 
them , it is also constantly found in the atmo- 
sphere, constituting about W^th part of the 
whole , its presence is easily detected by lime 
water, over which it forms a film ilmost in- 
stantly In the breathing of animals this gas 
is constantly produced , about 4 per cent of 
the air expired by man, is usually carbonic 
acid, and the atmospheric ar inspired loses the 
same quantity of oxygen 

Water absorbs just its o\\n bulk of carbonic 
acid gas , that is, the density of the gas in the 
water after agitation, is the same as the density 
of the incumbent gas above, and the elasticity 
of the eas m the water is unimpaired The 



SUBJECT INDEX 



377 



Potassium tetrasulphide 172 

tetrathionate, 176 

tetroxide, 170 

thiocarbonate, 184 

thiocyanate, 184 

thiosulphate, 176 

tn lodate, 169 

tnoxide, 170 

tnselemde, 177 

tnsulphide, 172 

tritellunde, 177 

tnthionate, ] 76 
Proustite, 290 
Pyrargynte, 290 

RICKARDITE, 283 
Rock salt, 81 
Rosette coppei, 247 
Rozan process, 292 
Rubidamide, 196 
Rubidium See Chapter A I 

atomic weight, 189 

chemical propertiep 18Q 

detection 199 

estimation 1)SL 

history, 188 

ion, 189 

occurrence, 188 

physical properties 2 1 8^ 

Water on, ^ 
Rubidium alum, 188 

ammonohthiate, 241 

ammonosodiate 241 

arsenate 198 
-arsemte 198 

auri bromide 345 

bromide, 192 
carbonate 19Q 

--tarnalhte 188 
chloiatc 19} 

rhlonde 101 
- dioxide 1M4 

disulplud< I 1 ) > 
dithionaU l c )l 
fluoiidi HI 
hydiidt 100 
h>diog<ii( ubonnto l^S 

- mknnti 1% 

- sulphite I0 r > 

- sulphide l'K 
hydio\id< 104 
iodU( I ( M 
iodide 1M2 

nut isilu iU l<^ 



nitiati 

- nitndi 

nitiitc 



1 ( )7 
1 ( )(> 
1<)7 



~ pent isiilphide, W 

pei cai bon ate 108 

perchloiate 193 

penodate 19 J 

peroxides 194 

persulphate 195 

phosphate 197 



Rubidium phosphide, 1Q7 

polyiodides, 193 

selenate, 196 

sulphate 195 

sulphide, 194 
tellurate, 196 

tetrasulphide, 195 

tetrathionate 106 

tetroxide, 194 

thiosulphate, 196 

tnsulphide, 195 

tnthionate 196 
Ruby copper, 242, 267 

Rrd ammomacum, 211 
Sal armomacum, 211 
Scheele's green, 285 
Schomte, 173 
Silver See Chapter X 

amalgamation, 290 

applications, 296 

atomic weight, 296 

chemical properties 293 

Colloidal, 294 

cupellation, 293 

detection 320 

estimation, 320 

history 290 

ion, 296 

hxiviation 291 

occunence, 290 

- physical properties 4 293 

preparation, 290 

- le fining 293 

- smelting 292 

- Spitting of 2<H 
uses 296 

Silver &ee Argentic 
- alloys, 301 
arsenate 318 
aisonite 31 b 
aimchloiule U3 
ixmcvanide, 350 
iiiiolniocyanate 340 
i/ide 314 
boiatt 320 
hi ornate 310 
biormde 30f> 
caibidi 51 S 



hlontc J09 
yanid( HO 
liphospludt ^1^ 
(lithioiial* Ul 
Huoiidt 102 
hypochlonto {00 
h y point i it t JI r > 
hypophospln1< M S 
lodatc 310 
iodide 308 
metaphosplmtf U8 
- monoxide 31 1 

nitrate, 315 

nitrite 315 



382 OXYGEN WITH CARBONE, 

phosphate of lime and charcoal were ob- 
tained 

Carbonic acid is decomposed by electricity 
into carbonic oxide and oxsgen I assisted 
Dr Henry m an experiment by which 52 
measures of caibonic acid were made 59 mea* 
sures by 75O shocks , the gas after being 
washed became 25 measures , whence these 
had arisen from the decomposition of 18 tnea* 
sures of acid , these 25 measures consisted of 
16 carbonic oxide and 9 oxygen , for, a per- 
tion being subjected to nitrous gas, manifested 
d of its bulk to be oxygen , and the rest was 
fired by an electric spark, and appeared to be 
almost \vholly converted into carbonic acid 

Carbonic acid then appears to be a ternary 
compound, consisting of one atom of charcoal 
and two of oxygen , and as their relative 
weights in the compound are as 28 72, we 
have 36 28 754= the weight of an 
atom of charcoal , and the weight of an atom 
of carbonic acid is 19 4 times that of hydrogen 
The diameter of an atom of the acid m an 
elastic state is almost exactl) the same as that 
ofh\drogen, and is therefore represented by 
1 , consequently a given volume of this gas 
contains the same number of atoms as the same 
volume of hydrogen 



SUBJECT INDEX 



379 



Sodium tnsulphide, 113 
tnthionate, 126 
Spodumene, 52 
Stromeyente, 290 
Struvite, 211 
Sylvamte, 322 
Sylvine, 152 

TENOBITE, 242, 275 
Thenardite, 117 
Thonte, 55 
Tile copper, 247 



Tmoal, 81, 149 
Torta, 291 

Tough pitch copper, 247 
Trichalcite, 286 
Tnphylhte, 52 



WATER gas, 14 

glass, 148 
White metal, 244. 

tellurium, 322 
Whitneyite, 271 



PRINTED IN GREAT BRITAIN BY NEILL AND CO LTD EDINBURGH 



384 OXYGEN WITH SULPHUR 

nate ofmlphw > as its formation is similar to 
that of muriate of iron, &c in hke circum* 
stances Now, it has been shewn that oxy^ 
muriatic acid is munatic acid united to oxygen, 
one atom to one , hence the atom of oxygen 
oxidizes an atom of sulphur, and the muriatic 
acid unites to the oxide, forming muriate of 
bulphur, or more strictly muriate of onde of 
sulphur 1 his oxide of sulphur, Dr Thomson 
finds, ib not easily obtained separate , for when 
the red liquid is poured into water, the oxide 
resolves itself into sulphur and sulphuric acid 
(Nicholson's Journal, vol 610*) 

When sulphuretted hydrogen gas and sul- 
phurous acid ga$ are mixed over mercury, in 
the proportion of 6 measures of the former to 5 
of the latter, both gases lose their elasticity, 
and a solid deposit is made on the sides of the 
tube 1 he common explanation given of this 
fact is, that the hydrogen of the one gas unites 
to the oxygen of the other to form water, and 
the sulphur of both gases u> precipitated This 
explanation is not correct , water is indeed 
formed, as is stated , but the deposition con- 
sists of a mixture of two solid bodies, the one 
sulphur, the other sulphurous oxide they may 
be distinguished by their colour, the former is 
yellow, the latter bluish white , and when 
t-W are hnth thrown into water, the former 



SULPHUROUS OXIDE 385 

soon falls down, but the latter remains for a 
long time suspended in the water, and gives 
it a milky appearance, which it retains after 
filtration It will appear in the sequel, that 5 
measures of sulphurous acid contain twice as 
much oxygen as the hydrogen in 6 measures 
of sulphuretted hydrogen require , it follows, 
therefore, that one half of the oxygen ought 
still to be found m the precipitate, which 
accords with the above observation Again, 
it water, impregnated with each of the gases, 
be mixed together till a mutual saturation takes 
place, or till the smell of neither gas is ob- 
served after agitation, a milky liquid is ob- 
tained, which may be kept for some weeks 
without any sensible change or tendence to 
precipitation Its taste is bitter and somewhat 
acid, very different from a mere mixture of 
sulphur and water When boiled, sulphur is 
precipitated, and sulphuric acid is found in 
the clear liquid The milkmess of this li- 
quid seems therefore owing to the oxide of 
sulphur 

It may be proper to remark that the white 
flowers of sulphur, commonly sold by the 
druggists, are not the oxide of sulphur They 
are obtained by precipitating a solution of sul- 
phuret of lime by sulphuric acid The) consist 
of 50 per cent sulphate of lime and 50 of sul- 



386 OXYGEN WITH SULPHUR 

phur, in some state of combination with the 
sulphate > for, the two bodies are not separable 
by lixiviation 

When sulphur in a watch glass is ignited, 
then suddenly extinguished, and placed on a 
stand over water, and covered with a receiver, 
the sulphur sublime* and fills the receiver with 
white fumes On standing for some minutes 
or an hour, the sulphur gradually subsides, 
and forms a fine yellow film over the surface of 
the water The air in the receiver loses no 
oxygen by this process But when sulphur 
ignited, is placed in the circumstances above- 
mentioned, it burns with a fine blue flame, 
emitting some bluish white fumes, scarcely 
perceptible at first , as the combustion con- 
tinues these fumes increase, and towards the 
conclusion, when the oxygen begins to be de- 
ficient, they rise up in a copious stream, and 
till the receiver so that the stand is scarcely 
visible It a portion of the air is passed 
through water, it still continues white In 
the space of an hoar the air in the receiver be- 
comes clear , but no traces of sulphur are seen 
onthesurface of the water The whiteness m 
this last case does not, therefore, seem to arise 
from sublimed sulphur, but from the oxide of 
sulphm, which is formed when there is not 
oxygen sufficient to form sulphurous acid , tV* 



SULPHUROUS OXIDE 387 

last is known to be a perfectly transparent elastic 
fluid Whether the sulphurous oxide in this case 
is absorbed by the water in that state, or is gra- 
dually converted into sulphurous or sulphuric 
acid, I have not been able yet to determine 

When a solution of sulphuret o^ lime has 
been exposed to the air for a few weeks, till it 
becomes colourless, and sulphur is no longer 
precipitated, if a little muriatic acid be added 
to it, the whole becomes milky, and exhales 
sulphurous acid , after some time sulphur is 
deposited, and the sulphurous acid vanishes, 
leaving muriate of lime in solution This 
milkmess must be occasioned by sulphurous 
oxide , for, sulphite of lime, treated in like 
manner, exhibits no such appearance 

As far, then, as appears, sulphurous oxide 
is a compound of one atom of sulphur and one 
of oxygen, it is capable of combining with 
muriatic, and perhaps other acids, when sus- 
pended m witer, it gives it a milky appear- 
ance and a bitter taste, and the mixture being 
heated, the oxide is changed into sulphur and 
sulphuric acid An atom of sulphur being 
estimated, from other consicK ration* hereafter 
to be mentioned, to weigh 13, and one of oxy- 
gen weighing 7, it will follow that o\ide of 
sulphur is constituted of fi5 sulphur and '35 
oxygen per cent 



588 OXYGEN WITH SULPHtTH, 



2 Sulphurous Acid 

When sulphur is heated to a certain degree 
in the open air, it takes fire and burns with a 
blue flame, producing by its combination with 
oxygen an elastic fluid of a well known and 
highly suffocating odour , the fluid is called 
sulphurous acid Large quantities of this acid 
are produced by the combustion of sulphur in 
close chambers, for the purpose of bleaching 
or whitening flannels and other woollen goods 
In this way, however, the acid never consti- 
tutes more than 4 or 3 per cent of the volume 
of air, and is therefore much too dilute for 
chemical investigations It may be obtained 
nearly pure by the following process To two 
parts of mercury by weight put one part of 
concentrated sulphuric acid in a retort, apply 
the heat of a lamp, and sulphurous acid gas 
will be produced, which m?y be received 
over mercury The reason of this is, each 
atom of mercury receives an atom of oxygen 
from one of sulphuric actd, and the remainder 
of the sulphuric atom constitutes one of sul- 
phurous acid, as will be evident from what 
follows 

Sulphurous acid is unfit for respiration and 
for combustion Us specific gravity, according 



SULPHUROUS ACID 389 

to Bergman and Lavoisier, is 2 05 , according 
to Kirwan, 2 24 , by tny own trials, it is 2 3 
I sent a stream of the gas, after it had passed 
through a cold vessel connected with the re- 
tort, into a flask of common air , this was after- 
wards weighed, and the quantity of acid gas 
then ascertained by water , it appeared by two 
trials, agreeing with each other, that 12 ounce 
measures of the gas weighed 9 grams more 
than the same quantity ot common air, and 
this last weighed 7 grains nearly Water ab- 
sorbs about 20 times its bulk of this gas at a 
mean temperature, according to my expe- 
rience , but some say more, others less The 
quantity absorbed, no doubt, will be greater 
as the temperature is less Hence, it seems 
that water has a chemical affinity for the gas , 
but the whole of it escapes if long exposed to 
the air, except a small portion which is con- 
verted into sulphuric acid 

When water, impregnated with sulphurous 
acid, is exposed to oxygen in a tube, the oxy- 
gen is slowly imbibed, and sulphuric acid 
formed In twelve days, 150 measures of the 
acid, absorbed by water, took 3 a of oxygen, 
leaving a residuum of oxygen and sulphurous 
acid When sulphurous acid gas and oxygen 
gas are mixed and electrified for an hour over 
mercury, sulphuric acid is formed , but I do 



390 OXYGEN WITH SULPHUR 

not find that the proportion of the elements of 
the acids tan in this way bt ascertained , for, 
the mercury becomes -o\idized, and conse- 
quently liable to form an union with either of 
the acids The two gases also combine, when 
made to pass through a red hot porcelain tube 
Sulphurous acid is said to be decomposed by 
hydrogen and charcoal at a red heat , sulphur is 
deposited, and water or carbonic acid formed, 
according as the case requites When a mea- 
sure of oxymunatic acid gas is put to a measure 
of sulphurous acid gas, over mercury, the sul- 
phurous acid is converted into sulphuric , but 
no e\act result can be obtained, from the rapid 
action of the former gas on mercuiy 

Sulphurous acid oxidizes few of the metals , 
but it possesses the common properties of acids, 
and unites with the alkalies, earths, and me- 
tallic o:xide:>, forming with them salts deno- 
minated sulphites 

It remains now to investigate the number 
and weight of the elements in bulphurous acid 
I have made a great number of experiments 
on the combustion of sulphur in atmospheric 
air, in Various circumstances , but those I 
in on particularh rely upon, were made in a 
receiver containing 400 cubic inches it was 
open at top, and had a biass cap, by means of 
which an empt) bluddei couJJ be attached to 



SULPHUROUS ACID 391 

the receiver, in order to receive the expanding 
air , a small stand was provided, and a watch 
glass was placed on it, filled with a known 
weight of the flowers of sulphur , the whole 
was placed on the shelf of a pneumatic trough, 
and as soon as the sulphur was lighted by an 
ignited body, the receiver was placed over if, 
with its margin in the water , the combustion 
was then continued till the blue flame expired * 
near the conclusion, white fumes> arise copi- 
ously, and fill the receiver A small phial 
was then filled with water, inverted, and care- 
fully pushed up mto the receiver to withdraw 
a portion of air for examination , the receiver 
was then removed, and the loss of sulphur 
ascertained The residuary gas in the phial 
was fired with hydrogen in Volta's eudiometer 
The loss of sulphur at a medium was 7 grainy 
and the oxygen in the residuary gas was at a 
medium 16 per cent or rather more, the 
weight of oxvgen> therefore, which had dis- 
appeared, was from 5 to 6 grains Hence it 
may be said, that 7 grains of sulphur com- 
bined with 5^- of oxygen , but as the white 
fumes are oxidised inferior to sulphurous acid, 
it is most probable that sulphur requires its 
own weight of oxygen nearly to form sul- 
phurous acid In confirmation of thb, it is 
observable, that no material change of bulk i^ 



392 OXlLGLtf WI1H SULPHUR 

effected in the gas by the combustion, and 
this is also remarked in the analogous com- 
bustion of charcoal Thus, then, the specific 
gravity of sulphurous acid should exhibit a 
near approximation to t\\ ice that of oxygen, 
as it is found to do above Now, as it would 
be contrary to all analogy, to suppose sul- 
phurous acid to consist of 1 atom of sulphui 
and 1 of oxygen, we must presume upon its 
being 1 of sulphur and 2 of oxygen , and hence 
the weight of an atom of salphur will be 14 
times that of hydrogen 

Another and more ngtd proof of the consti- 
tution of sulphurous acid, we obtam from the 
combustion of sulphuretted h\diogen jn Volta's 
eudiometer This compound, it will be 
shewn, contains exactly its own bulk of hy- 
drogen , the rest is sulphur Their relative 
weights, as appears from the specific gravity, 
must be J to 14- nearly, now,, when sulphu- 
retted hydrogen is exploded with plenty of 
oxygen over mercury, the whole of the last 
mentioned gas is converted into water and 
sulphurous acid , U is found that 2 measuies of 
the combustible gas combine with 3 measures 
of oxygen , but 2 measures of hydrogen take 
1 measure of oxjgen, therefore, the sulphur 
takes the other 2 measures , tbat ib, the atom 

of O\\ ffCIl 10r itS 



SI LPHUROUS ACID 393 

combustion, and that of hydrogen 1 atom of 
oxygen , which gives the same constitution 
as that deduced above for sulphurous acid 

The proportions of sulphur and oxygen in 
this acid, ha\e been variously stated, mostly 
wide of the truth We have one account that 
gives 85 sulphur and 15 oxygen Dr Thomson, 
m Nicholson's Journal, vol 6 ? page 97, gives 
68 sulphur and 32 oxygen , but in his Ap- 
pendix to the 3d edition of his Chemistry, he 
corrects the numbers tp 53 sulphur and 47 
oxygen. Desormes and Clement say 59 sul- 
phur and 41 oxygen (ibid vol 17 page 42) 
According to the preceding conclusions, if the 
atom of sulphur be stated at 14 , then the pro- 
portion of sulphur to oxygen \\ill be 50 sul- 
phur to 50 oxygen, or equal weights , but if 
sulphur be denoted by 13, then sulphurous 
acid will consist of 48 sulphur and 52 oxygen 
per cent , which numbers I consider as the 
nearest approximation the diameter of the 
elastic atom of sulphurous acid i* rather less 
than that of hydrogen, as appears from the 
circumstance that 5 measures of the gas sa- 
turate 6 measures ot sulphuretted hydrogen 
whiqh last contain as many atoms as the like 
measures of i On this account, the 
diameter of an atom of sulphurous acid may 



394 OXYGEN WITH SULPHUR 

be denoted by 95, and the number of atoms 
in a given volume, to that of h\ drcgcn in the 
same volume, will be as 6 to 5, or 120 to 100 



3 Sulphuric Actd 

The sulphuric acid of commerce, commonly 
known in this country by the name of oil of 
vitriol, is a transparent liquid of an unctuous 
feel, of the specific gravity 1 84, and very 
corrosive , it acts powerfully on animal and 
vegetable substances, destroying their texture, 
and mostly turning them black This acid 
was formerly obtained from green vitriol (sul- 
phate of iron) by distillation , hence the name 
whiohc acid It is now commonly obtained 
by burning sulphur, mixed with a portion of 
nitre, (from 1th to 2 l ^th of its weight) in leaden 
chambers, sulphuric acid is formed and drops 
down into witer, which covers the floor of 
the chamber* , this water, when charged suf- 
ficiently \\ith acid, is drawn off, and subjected 
to evaporation till the acid is concentrated in a 
higher degiee , when it is put into glass retorts, 
and placed in a sind bath , the weaker pait of 
the acid is distilled into receivers, and the 
others concentrated nearly as much as is pos 



SITLPHTTRIC \CID 395 

sible in the circumstances The acid in the 
receivers is again boiled down and treated as 
before 

Some authors have affected to consider the 
theory of the formation ot sulphuric acid as 
very obvious , the nitre, they sa\, furnishes a 
part of the oxygen to the sulphur, and the 
Atmosphere supplies the rest Unfortunately 
for this explanation, the nitre, if it were all 
oxygen, would not furnish above T ~th of what 
is wanted 9 but nitre is only 55 per cent oxy- 
gen , it cannot, therefore, supply the sulphur 
with much more than -^-th pait ot what it 
wants, if all the oxvgen \\ere extricated , but 
not more than -| or -Id of this small portion is 
disengaged from the potash , for, the salt be- 
comes a sulphate instead of a nitrate, and re 
tains most of the OMgen I L had, 01 acqures 
oxygen again from some source Several veil 
informed manufacturers, awaie of the fallacy of 
the above explanation, Inve attempted to di- 
minish the nitre (which is an article ot great 
expence to them), 01 to discard it altogether , 
but they find it mdispensibly necessary in some 
portion or other, for, without u thev obtain 
little but sulphurous acid, \\hich is in great 
part mcondensible, and not the acid they 
want The manner in which the nitre operates 
for a long time remained an enigma At 



396 OXYGEN WITH SULPHUR 

length Desormes and Clement, two French 
chemists, have solved the difficult), as may be 
seen in an excellent essay in the Annal de 
Chirme, 1806, or m Nicholson's Journal, vol. 
17 These authors shew, that in the com- 
bustion of the usual mixture of sulphur and 
nitre, sulphurous acid is first formed, and ni- 
trous acid or nitrous gas liberated, partly from 
the heat, and partly perhaps from the action of 
sulphurous acid , the nitrous gas or acid be- 
comes the agent in oxidizing the sulphurous 
acid, by transporting the oxygen of the atmo- 
spheric air to it, and then leaving them m 
union, which constitutes sulphuric acid The 
particle of nitrous gas theft attaches another of 
oxygeq to itself, and transports it to another 
atom of sulphurous acid , and so on till the 
whole is oxidized Thus the nitrous acid 
operates like a ferment, and Without it no sul- 
phuric acid would be formed 

ihis theory of the formation of sulphuric 
acid has so very imposing an aspect, that it 
scarcely requires experiment to prove it It 
is, however, very easily proved by a direct 
and elegant experiment Let 100 measures 
of sulphurous acid be put into a dry tube over 
mercury, to which add 60 of oxygen , let then 
10 or 20 measures of nitrous gas be added to 
the mixture in a few seconds the inside of 



SULPHURIC ACID 397 

the tube becomes covered with a crystalline 
appearancej like hoar frost, and the mixture is 
reduced to ^d or ^ih of its original volume 
If now a drop of water be admitted, the cr)s* 
tallme matter is quickly dissolved into the wa- 
ter, sparkling as it enters, and the gases en- 
tirely lose their elasticity, except a small resi- 
duum of azote and nitrous gas If the thbe is 
then washed out, the water tastes strongly acid, 
but has no smell of sulohurous acid It is 
evident, that in th*s process the nitrous gas 
unites to the oxygen, and transports it to the 
sulphurous acid, which, receiving it from the 
nitrous, becomes sulphuric acid It appears, 
moreover, that solid sulphuric acid is formed 
when no water is present , and consequently 
this is the natural state of sulphuric acid en- 
tirelv free from water It must b observed, 
that if an} water in substance is present when 
the mixture of gases is made, the uater seizes 
the nitrous acid as it is formed, and coni>e- 
quently prevents it o\idizing the sulphurous 
acid , on the other hand, the presence of 
water seems necessary in the sequel, to take 
the new formed sulphuric acid away, in order 
to facilitate the oxidizement of the remaining 
sulphurous acid The oxygen necessary to 
saturate 100 measures of sulphurous acid seems 
to be about 50 measures , but it is difficult to 



OX \ GEN WITH StTLPHlTK 

ascertain this with precision, because the ni- 
trous gag takes up the superfluous oxygen, and 
begins to act upon the mercury 

Now, it has been shewn, that sulphurous 
acid contains nearly its own bulk of oxygen, 
and is constituted of 1 atom of sulphur and 2 
of oxygen , and it appears fiom the above, that 
half as mfcch oxygen more, that is, 1 atom, 
converts it into sulphuric aud hence, the 
sulphuric acid atom is constituted of 1 atom of 
sulphur and 3 of oxygen , and if the atom of 
sulphur be estimated at 13 in weight, and 
the 3 of oxygen at 21, the whole compound 
atom will weigh 34 times the weight of an 
atom of hydrogen , that is, pure sulphuric 
acid consists of 38 sulphur and 62 oxjgen per 

cent 

In the year 1806, by a careful comparison 
of all the sulphates, the proportions ofr which 
are well known, I deduced the weight of the 
atom of sulphuric acid to be 34 , it now ap- 
pears that the same weight is obtained syn- 
thetically, or without any reteiencc to its 
combinations , the perfect agreement of these 
deductions, renders it bevond doubt that the 
u eight is nearly approximated, and confirms 
the composition of the atom which has j<ist 
been stated 

elv anv chemical ormciples 



SUJLPHUETC ACID 399 

the proportions of \\hich have been so di- 
versely determined by experimentalists, as 
those of sulphuric acid the following table 
will sufficiently prove the observation , ac- 
cording to 

Berthollet 72 sulphur + 28 oxygen 

Tromsdorf 70 

Lavoisier 69 

Chenevix 

Thenard 

Bucholz 

Richter 

Klaproth 

Chenevix's result would have been 4* sul- 
phur + 56 oxygen, if he had adopted 33 per 
cent acid in $ulphate of barytes, which is 
now generally admitted The method which 
be and the later experimentalist have taken, 
as to distil nitnc acid from a given weight of 
sulphur, till the whole or some determined 
pari of the sulphur 1$ converted into sulphuric 
ac^d, the acid ib then saturated unh bar)tes, 
and the weight of the salt ascertained 

Notwithstanding the above theory of th 
formation of sulphuric acid was such a* to 
convince me of its accuracy, I was desirous to 
see the manufacture ot it on a large scale 




400 OXYGEN WITH SULPHUR 

and by the generous invitation of Mr Walking, 
of Darcy Lever, near Bolton, I had lately an 
opportunity of gratifying myself by the in- 
spection of hts large and well-conducted acid 
manufactory, near that place When opening 
a small door of the leaden chambers, there is- 
sued a volume of red fumei> into the air, which 
by their colour and smell, left no room to 
doubt of their being the fumes of nitrous acid 
There was scarcely any smell of sulphurous * 
acid From the nitrous fumes, one would 
have been inclined to think that the chambers 
were filled with nitrous gas I was particu- 
larly anxious to know the constitution of the 
air in the interior of the chambers, and Mr 
Watkins was so obliging as to send me a 
number of phials of air taken from thence 
Upon examination, the air was found to con- 
sist of H) per cent oxygen and 84 azote 
1 here was no smell of sulphurous acid, and 
very little of nitrous acid, this lat>t having 
been condensed m passing through the water 
In fact, it seems that the nitrous acid fumes 
never make more, perhaps, than 1 per cent 
upon the \\hole volume of air , nor can the 
OX) gen be ever reduced much below 16 pei 
cent, because the combustion would instantly 
cease A constant dropping is observed from 
th* rhof nf the chambers internally , these drops 



StTLPHURIC ACID 401 

bung collected, were found to be of the spe- 
cific gravity 1 6, they had no sulphurous smell, 
but one slightly nitrous 

It is not very easy to suggest any plausible 
alteration in the management of a manufactory 
of this article Nitrous acid must be present , 
but whether it is best obtained by exposing 
nitre to the burning sulphur, or by throwing 
in the vapour of nitrous acid by direct distil- 
lation, may be worth enquiry Loss of nitrous 
acid is unavoidable, partly by its escape into 
the air during the periods of ventilation, and 
partly by its condensation m the watery acid, 
on the floors of the chambers , a regular supplj 
must, therefore, be provided > but if thi? ex* 
ceed a certain quantity, it not only increases 
the expence, but ib injurious to the sulphuric 
acid in some of its applications There must, 
in all probability, be some figuie of the cham- 
bers better than any other, in regard to their 
proportions as to length, breadth, and height , 
this, perhaps, can be determined only by ex- 
perience As water absorb* th^ nitrous acid 
with avidity, high chambers, and the com- 
bustion earned on at a distance from the \\ater, 
must be circumstances favourable to econom) 
in regard to nitre 

Sulphuric acid has a strong atti action for 
watei , it even takes it from the atmosphere 



402 OXYGEN WITH SULPHUR 

in the state of steam, with great avidity, and 
is therefore frequently used in chemistry for 
what is called dryntg the air When mixed 
with water, sulphuric acid produces much 
heat, as has already been stated in the first 
part of this work* 

When sulphuric acid is boiled upon sul- 
phur, it has been said sulphurous acid is 
formed I have not found this to be the case 
But charcoal and phosphorus decompose the 
acid by heat , and the results are carbonic acid, 
phosphoric acid, and sulphurous acid 

Sulphuric acid combines with the alkalies 
and earths in general, forming with them 
salts denominated sulphates On the metals 
this acid acts variously, according to its con- 
centration , when diluted with 3 or 6 times its 
bulk of water, it acts violentl) on iron and 
zinc , great quantities of hydrogen gas are 
produced, which proceed from the decompo- 
sition of the water, and the oxygen of the 
water unites with the metal, to which the acid 
also joins itself, and a sulphate is thus formed 
When the acid is concentrated, its action on 
metals is less violent, but by the assistance of 
heat, it oxidizes most of them, and gives off 
sulphurous acid 

As the sulphuric acid exists in various de- 
gree;, of concentration, it becomes a matter ot 



SULPHURIC ACID 403 

importance both to its manufacturer, and to 
those who use it largely, as the dyers and 
bleachers, to know the exact strength of it ; 
or in other words, to know how mu^h water 
is combined with the pure acid in any spe- 
cimen This subject engaged the particular 
attention of Kirwan some years ago, and he 
has furnished us with a table of the strengths 
of sulphuric acid, of most densities There 
are two things requisite to form an accurate 
table, the one is to ascertain the exact quan- 
tity of real acid in some specimen of a given 
specific gravity , the other is tn observe care- 
fully the effects produced on the specihc gra- 
vity of such acid, by diluting it with a given 
quantity of water Mr Kirwan has succeeded 
\ery well in the former, but has been pecu- 
liarly unfortunate in the latter The errors of 
his table seem to have been known for the last 
10 years to everv one, except the editors of 
works on chemistry The following table 
exhibits the results of my own experience on 
this acid for several jears 



404 OXYGEN WITH SULPHUR 

Table of the quantity of real acid in 100 parts of liquid 
sulphui ic acid, at the temperature 60* 



Atoms 


Acid per cent 
by weight 


Acid per cent 
by measure 


Specific gra 
vity 


Boiling point 


Aa. Water 










1+ 


100 


unknown 


unknown 


unknown 


1+ 1 


81 


150 


850 


62Q<* 




80 


148 


849 


605 




79 


146 


848 


590 




78 


144 


847 


575* 




77 


142 


845 


560* 




76 


140 


842 


545 




75 


138 


838 


530 




74 


135 


833 


515 




73 


133 


827 


501 




72 


131 


819 


487* 




71 


120 


810 


47 3* 




70 


326 


801 


460 




69 


124 


791 


447 


1+ 2 


68 


121 


780 


435* 




07 


118 


769 


422 




66 


116 


757 


410 




65 


113 


744 


400" 




64 


111 


730 


391 




63 


108 


715 


382* 




62 


105 


699 


374 




61 


103 


684 


367 




60 


100 


670 


360* 


1 + 3 


586 


97 


050 


350* 




50 


76 


520 


29O 




40 


50 


1-08 


260* 


1 + 10 


30 


39 


30+ 


240* 


1 +17 


20 


2t 


200 


224* 


1 +J8 


10 


11 


10 


218 



Rcmaiks on the piecedmg Table 

1 The acid of 81 per cent, is constituted of 
1 atom of acid and 1 of water It is the 
strongest possible acid that can be obtained by 
boiling the liquid acid , because at that strength 



SULPHURIC ACID 405 

the acid and water distil together, in the same 
way as nitric acid of 1 42 sp gravity, or mu- 
riatic of 1 094 It is a mistaken notion, that 
the common sulphuric acid of commerce is of 
the maximum strength, though it is of the 
maximum density nearly The fact is, acid 
nearly of the maximum strength varies very 
little in its specific gravity, by the addition or 
subtraction of a small quantity of water Here 
is Kirwan's principal eiror Acids of the 
strength of 81 and 80, do not differ more than 
1 in the third place of decimals , whereas, ac- 
cording to his table, the difference i* It times 
as great The acid of commerce varies from 
75 to 80 per cent of acid, or about 1 per cent 
in value, in the different specimens 1 have had 
occasion to examine This variation onlv 
changes the second figure in decimals an unit , 
though, according to Kirwan's table, the 
change is 7 times as much The specific gra- 
vity ought not to be the criterion of strength 
in acids above 70 per cent , the temperature 
at which they boil is a much better criterion, 
because it admits of a range of 12 01 13 toi 1 
per cent of acid Or the strength may be 
found by determining what quantity of \*ater 
must be added to reduce the acid to some 
known strength, a* that of the glacial acid 
ot 1 78 so gravity 



406 0X\GEN WITH SULPHUR. 

2 There is nothing further striking m the 
table till we come to the acrd, which is con- 
stituted of 1 atom to 2 of water , this acid 
possesses the remarkable property of congealing 
in a temperature at or above 32% and of re- 
maining congealed m any temperature below 
46 , its specific gravity is 1 78, as Keir found 
it, (Philos Trans 1787), and it contains 68 
per cent of real acid, both by theory and ex- 
periment 9 it is determined by theory thus 
one atom of sulphuric acid weighs 34, and 
2 of water 16, together making 50, hence, if 
SO 34 100 68 , it is found experimen- 
tally thus let 100 gram measures of glacial 
sulphuric acid be saturated with carbonate of 
potash r and the sulphate of potash be ob- 
tained , it will weigh, after being heated to a 
moderate red, nearly 270 grains, of which 
121 will be acid, and 149 alkali, according to 
the analyses of Kit wan and Wenzel If the 
liquid acid be of greater or less specific gra- 
vity, so as to contain even 1 per cent more or 
kss real acid, then it cannot be frozen in a 
temperature above 32, but may in a tempe 
rature a little below 32 If the liquid acid 
contain 3 per cent more or less than the 
glacial, it cannot be frozen without the cold 
produced bv a mixture of snow and salt , and 



SULPHURIC ACID 407 

per cent from the glacial, as Mr Keir deter- 
mined I find the frozen acid to be of the 
specific gravity 1 88 nearlv It seems pro- 
bable that the difficulty of freezing would in- 
crease in both sides, till the acids of 1 and I 
above, and 1 and 3 below 

3 The acids below SO per cent may, with- 
out any material error, have their strength 
estimated by the first and second figures of 
decimals m the column of sp gravity, thus 
acid of 1 5 per cent strength, will have the 
specific gravity 1 15, &c 



SECTION 5 

OXYGEN WITH PHOSPHORUS 

There are only two compounds of oxygen 
and phosphorus yet known they both have 
the characters of acids , the one is denomi- 
nated phosphorous acid, the other phosphoric 
acid ft is extremely probable that the former, 
though recognised as an acid, is yet in the 
lowest degree of oxidation, and may therefore 
with equal propriety be called phosphorous 
oxide, plwsphoiic oxide, or, after the manner 
of metals, oxide of phosphorus We shall, 
he common name 



JOB OXYGEN WITH PHOSPHORUS 

1 Phosphorous Acid 

When phosphorub is exposed for some days 
to the atmosphere, it gradually acquires oxy- 
gen, an4 is converted into an acid liquid 
This process may be effected by putting small 
pieces of phosphorus on the sloping sides of a 
glass funnel, and suffering the liquid to drop 
Into a phial as it is formed The liquid, called 
phosphorous acid, is viscid, tastes sour, and is 
capable of being diluted "with water to any 
amount It has the usual effect of acids on the 
test colours When heated, water is evapo- 
rated, and afterwards phosphuretted hydrogen 
gas , finally, there remains phosphoric acid m 
the vessel It should seem from this, that 
heat gives the oxygen of one part of the phos- 
phorous acid to another, by \vhich the latter 
is changed into phosphoric acid, and the phos- 
phorus of the former is liberated , but at that 
degree of heat the liberated phosphorus acts 
on the \iater , one part of it takes the oxygen 
to form more phosphorous acid, and the other 
takes the hydrogen to form phosphuretted 
hydrogen , and thus the process is carried on 
till all the phosphorus is in the state of phos- 
phoric acid, or phosphuretted hydrogen It 

IS Drobahle tint* in this wav 



PHOSPHOROUS ACID 409 

is divided, so that two thirds of it are united 
to oxygen, and one third to hydrogen , but 
this has not been ascertained by direct ex- 
periment 

Phosphorous acid acts upon several metals, 
oxidizing them by the decomposition of wa- 
ter, and at the same time giving out phosphu- 
retted hydrogen , the resulting metallic salts 
are, it is supposed, phosphates, the redundant 
phosphorus being carried off by the hydrogen 
This acid combines with the alkalies, earths, 
and metallic oxides, and forms with them a 
class of salts called phosphites 

When nitric acid is put to phosphorous acid, 
and heat applied, the mtnc acid is decom- 
posed, half of its oxygen unites to the phos 
phorous acid, and converts it into phosphoric 
acid, and the rest of the nitric acid escapes in 
the form of nitrous gas 

The proportion of the t\\o elements consti- 
tuting phosphorous acid has not hitherto been 
ascertained , I am inclined to believe, from the 
experiments and observations about to be re- 
lated concerning phosphoric acid, that phos- 
phorous acid is composed of 1 atom of phos- 
phorus, weighing 9 nearly, and 1 or oxygen, 
weighing 7 , the compound weighing 16 If- 
this be the case, it may appear singular that 
Bone of the other elements exhibit acid pro- 



410 OXTGEN WITH PHOSPHORUS 

perties when combined with 1 atom of oxy- 
gen , but it should be observed, that the phos- 
phoric oxide is in a liquid form, and disposed 
to separate into phosphorus and phosphoric 
acid, circumstances that do not combine m 
regard to the other oxides In fact, phos- 
pherous acid may be considered as phosphoric 
acid holding phosphorus m solution, rather 
than as a distinct acid 



2 Phosphoric Acid 

Though some of the compounds of phos- 
phoric acid, and the earths and alkalies, are 
common enough, yet this acid, m a pure 
state, is rarely obtained m any considerable 
quantity, requiring a process both tedious and 
expensive There are three methods by which 
phosphoric acid may be formed 1 If a small 
portion of phosphorus, namely, from 5 to 20 
grains, be ignited, and immediately covered 
with a large bell glass, over water, the phos- 
phorus burns with great brilliancy, and soon 
fills the vessel with white fumes , in a short 
time, the combustion ceases , after which the 
fumes gradually subside, or adhere to the side 
of the glass m the form of dew , these white 
fumes are pure phosphoric acid 3 If a small 



PHOSPHORIC ACID 41 1 

piece of phosphorus be dropped into heated 
nitric acid in a phial or gas bottle, a brisk 
effervescence ensues, occasioned bv the escape 
of nitrous gas, and the phosphorus gradually 
disappears, being converted into phosphoric 
acid, and mixed with the remaining nitnc 
acid , another small piece may then be dropped 
into the liquid, and so on in succession till 
the nitric acid is almost wholly decomposed a 
the remaining liquid may then be gradually 
increased m temperature, to drive off all the 
nitric acid , what is left is a liquid consisting 
of phosphoric acid and water , by increasing 
the heat to a moderate red, the water is driven 
off, and liquid phosphoric acid remains, which 
on coolwig becomes like glass 3 If phospho- 
rous acid be prepared by the slow combustion 
of phosphorus, as mentioned above, and then 
a portion of nitric acid added to the liquid, 
and heat be applied, the nitric acid gives part 
of its oxygen to the phosphorous acid, and 
nitrous gas escapes What remains, when 
heated, is pure phosphoric acid 

Of these three processes, the first may be 
recommended when the object is to find the 
proportion of the elements of the acid , but the 
second and third, when the object is to pro 
cure a quantity of acid for the purposes o f in- 
vestigation Of these the third is preferable 



412 OXYGEN WITH PHOSPHORUS 

in an economical point of view, because it 
requires only half as much nitric acid By 
calculation, I find that 20 grains of phos- 
phorus will require 200 grains of nitric acid 
of 1 35, by the second process, but only 100 
grains by the thud , but a small excess 
should always be allowed for loss by evapo- 
ration, &c 

Phosphoric acid, in the state of glass, is de- 
liquescent when exposed to the air , it be- 
comes oily, and may be diluted with anj 
quantity of water This acid is not so cor- 
rosive as some others , but it has the other 
acid properties of a sour taste, of reddening 
vegetable blues, and of combining with the 
alkalies, earths, and metallic oxides, to form 
salts, which are called phosphates It has the 
power of oxidizing certain metals, by decom- 
posing water m the minner of sulphuric acid y 
the oxygen of the water unites to the metal, 
and the hydrogen is liberated m the state of 
gas Charcoal decomposes this acid, as well 
as the phosphorous, in a red heat , hence the 
process for obtaining phosphorus form super- 
phosphate of lime 

Nothing very certain has been determined 
respecting the relation of the strength of this 
acid to the specific gravity of the liquid solu- 
tion borne experience I have had, makes me 



PHOSPHORIC ACID 413 

think the following table will be found nearly 
correct at all events, it may have its use till 
a better can be formed 

Table of the quantity of real acid m 100 parts 
of liquid phosphoric acid 



Acid per cent 
by weight 


Acid pei cent 
by measure 


Specific gravity 


50 


925 


185 


40 


64 


160 


30 


417 


1 39 


20 


246 


123 


10 


11 


1 10 



Lavoisier ascertained the relative weights of 
phosphorus and oxygen in phosphoric acid to 
be 40 to 60 nearly this was effected by burn- 
ing phosphorus in oxygenous gas This im- 
portant fact has been since corroborated by 
the experience of others I find a near ap- 
proximation to this lesult by burning phos- 
phorus in atmospheric air In a bell glass, 
containing 400 cubic inches of air, 5 grams of 
phosphorus were repeatedly burnt over water , 
the combustion at first was very vivid, but 
towards the conclusion it was languid , there 
\vas a residuum of moist, half burned phos- 
phorus in the cup, usually about 1 grain the 
glass had a flaccid bladder adapted to it to 
receive the rarefied air, so as to suffer none to 



414 OXYGEN WITH PHOSPHORUS. 

escape The air at first contained 20- per 
cent oxygen , but after the combustion, it 
contained only 16 or 16 j per cent , the tem- 
perature being about 40 at the time Whence, 
by calculation, it appears that in these in- 
stances I grains of phosphorus may be con- 
cluded to have united to 6 grains of oxygen 
Ihe data, indeed, would give a rather less 
proportion of ,ox\gen ; but it is probable that 
some phosphorous acid is formed near the con* 
elusion of the combustion 

With respect to the constitution of the phos- 
phoric acid atom, there can be but two opi- 
nions entertained Either it must be 1 atom 
of phosphorus with 2 atoms of oxygen, or 
with 3 of oxygen According to the former 
opinion, the phosphoric atom will wejgh 9, 
and the phosphoric acid atom 23 , according 
to the latter opimon, the phosphoric atom will 
weigh H, and the acid atom 35 We might 
appeal to the phosphates to determine the 
weight of the acid , but this class of salts has 
not been analyzed with sufficient precision 
Fortunately, theic is another compound of 
phosphorus which is subservient to our pur- 
pose , namely, phosphuretted hydrogen As 
the properties of this gas will be treated of in 
the proper place, we shall only observe here 
that the gas is a compound of phosphorus and 



PHOSPHORIC ACID. 415 

hydrogen, that it contains just its bulk of 
hydrogen , that its specific gravity is about 10 
times that of hydrogen , and that when fired 
*n Volta's eudiometer along with oxygen, it is 
converted into water and phosphoric acid, 
requiring 150 percent in volume of oxygen 
for its complete combustion , but is, notwith- 
standing, burnt so far as to lose its elasticity 
with 100 measures of oxygen These facts 
leave no doubt that the atom of phosphorus 
weighs 9 , that the atom of phosphoric acid 
weighs 23, being a compound of 1 with 2 of 
oxygen , that the atom of phosphorous acid 
is 1 with 1 of oxygen, weighing 16, and that 
phosphorous actd and water are formed when 
equal volumes of phosphuretted hydrogen and 
oxygen are exploded together 



SECTION 6 

HYDROGEN WITH AZOTfr, 

Only one compound of hydrogen and azote 
has yet been discovered it has been long 
known to chemists as an 'mportant element, 
-and under various names, according to the 
state m which it was exhibited, or to the ar- 
ticle from which it was derived , namely, w- 



416 HYDROGEN WITH AZOTE 

latile alkali^ hartshorn, spirit of sal ammo* 
mac, &r but authors at present generally dis- 
tinguish it by the name of ammonia Its nature 
and properties we shall now describe 



Ammonia 

In order to procure ammonia, let one ounce 
of powdered sal ammoniac be well mixed with 
two ounces of hydrate of lime (dry slaked 
lime), and the mixture be put into a gas 
bottle , apply the heat of a lamp or candle, 
and a gas comes over, which must be received 
in jars over dry mercury It is ammoniacal 
gas, or ammonia in a pure state 

This gas is unfit for respiration, and for sup 
porting combustion , it has an extremely pun- 
gent smell, but when diluted with common 
air, it forms an useful and well-known stimu- 
lant to prevent fainting The specific gravity 
of this gas has been found nearly the same 
by various authors, which is the more remark- 
able, as the experiment is attended with some 
difficulties that do not occur in many othe* 
cases According to Davy, 100 cubic inches 
of it weigh 1& grains, according to kirwan, 
182 grains, Allen and Pepys, 187, and 
Biot, 196, the mean of these, 186 grains, 



AMMONIA 417 

may be considered as a near approximation at 
the temperature 60 and pressure 30 inches of 
mercury hence the specific gravity is 6, the 
weight t/f atmospheric air being one 

Ammomacal gas sent into water, is con- 
densed almost with the same rapidity as steam , 
in this respect it corresponds with fluoric and 
muriatic acid gases The compound of water 
and ammonia forms the common hquid am- 
monia sold by the name of spirit of sal ammo- 
niac , this is the form in which ammonia is 
the most frequently used It is of great im- 
portance to ascertain the quantity of gaseous 
or real ammonia in given solutions of ammonia 
3n water This subject has been greatly neg- 
lected , a very good attempt was made about 
10 years ago by Mr Davy, to ascertain the 
quantity of ammonia in watery solutions, of 
different specific gravities > the result was 3. 
table, which may be considered an excellent 
first approximation , but it is to be regretted 
that so important an enquiry should not have 
attracted attention smce I have instituted a 
few experiments on this head, the results of 
which will no doubt be acceptable 

A phial, capable of holding UOO grains ot 
water, was partly filled with mercurj, and the 
rest with 200 grains of water, and inverted n 
mercury , into this 6000 gram measures of am 



HYDROGEN WITH AZOTE 

momacal gas were transferred , the liquid had 
not diminished sensibly m specific gravity; 
it required 24- gram measures of muriatic 
acid, 1 155, to saturate the water, by evapo- 
rating in a heat below boiling water, 12 grains 
of dry muriate of ammonia were obtained 
Mow, supposing 1400 measures of gas equal 
to 1 gram in weight, there would be found in 
the salt 5 7 grains of muriatic acid, 4 3 grains 
of ammonia, and 2 grains of water I found 
this method of proceeding not to be relied 
upon , for, though the mercury had recently 
been dried in an oven in the temperature 240, 
yet the ammomacal gas could not be trans- 
ferred from one graduated tube to another, 
without a lot>s of 10 or 15 per cent , I had 
reason to conclude, then, that the ammonia 
m the above salt was overrated In order to 
avoid this source of error, I adopted the method 
first used by Dr Priestley, of putting muriatic 
acid gas to the alkaline in the graduated tube , 
but here was still an objection, as the muriatic 
acid gas must be measured previously to the 
transfer, and it is equally absorbable by water 
with alkaline gas However, I found, as Dr 
Priestley had done before, that equal measures 
ot the t\\o gases as nearly as possible saturated 
each other For, when a measure of acid gas 
was put to one of alkaline, there was a small 



AMMONIA 

residuum of alkaline gas , and when the alka- 
hne was transferred to the acid, there was a 
small residuum of acid gas Having before 
concluded (page 287) that muriatic acid gas 
was of the specific gravity 1 61, I might have 
adopted the ratio of acid and alkali m muriate 
of ammonia to be 1 61 to 6 , and hence have 
inferred the quantity and volume of ammonia 
in a given solution, from the quantity of mu- 
riatic acid solution requisite to saturate it 
But there was one important circumstance 
against this , the atom of muriatic acid I knew 
weighed 22, and the ratio of i 61 to 6, is the 
same as 22 to 8 2 nearly , hence, the weight 
of an atom of ammonia must have been 8 2 or 
4 1, which I was aware was inconsistent with 
the previous determinations concerning azote 
and hydrogen Observing in the 2d \ol of 
of the Mtmout^ d'Aicucil, that Biot and Gaj 
Lussac find the specific gravity of muriatic 
acid gas to be so low as 1 278, and under- 
standing from conversation with Mr Davy, 
that he also had found the specific gravity of 
the jas to be considerablyless than I had con 
eluded, I was induced to repeat the experi- 
ment of weighing it, taking every care to 
avoid the introduction of liquid solution I 
*ent a stream of ac d gas, derued from com 
salt and concentrated sulphuric acid, 



420 HYDROGEN WITH AZOTE 

through an intermediate vessel, into a dry flask 
of common air, loosely corked, till it had ex- 
pelled |ths of the air, as appeared afterwards , 
the inside of the glass had a very slight opacity 
on its surface , it had gamed 1^ gram m 
weight , it was then uncorked and its mouth 
plunged into water, when -|ths of the flask 
were in a few moments occupied by the water 
Other trials gave similar results The flask 
held 6 grains of common air Whence I de- 
rive the specific gravity of muriatic acid gas to 
be 1 23, and am induced to apprehend that 
this is rather more than less than the truth 
The weights of equal volumes of muriatic acid 
gas and ammomacal gas will then be as 1 23 
to *6, or as 22 to 11, nearly, and if we as- 
sume that 11 measures of acid gas are sufficient 
for 12 of alkaline, which is not unlikely from 
experience , then we shall have 22 parts acid 
to 12 of ammonia for the constitution of mu- 
riate of immoma (exclusive of water), which 
will make the theory and experience har- 
monize , according to this view, muriate of 
ammonia must consist of 1 atom of muriatic 
acid and 2 of ammonia, each atom of ammo- 
nia being a compound of 1 atom of azote and 
1 of hydrogen However this may be, I find 
that 22 parts of real muriatic acid, 38 of nitric, 
and 3 1 of sulphuric, as determined by the re- 



AMMONIA 421 

spective foregoing tables, will saturate equal 
portions of any ammomacal solution , these, 
then, may be considered as tests of the quan- 
tity of real ammonia in different solutions, 
and if the ratio of 22 to 12, above adopted, 
be incorrect, it cannot be greatly so , and the 
error will be general, being so much per cent 
upon any table of ammomacal solutions The 
test acids I prefer for use, are such as contain 
half the quantities of acid above stated in 100 
gram measures Thus, 100 gram measures 
of muriatic acid, sp gravity 1 074, contain 
1 1 grains of real acid , 100 measures of nitric 
acid, I 141, contain 19 grains, and 100 mea- 
sures of sulphuric acid, 1 135, contain 17 
grains of real acid Now, 100 measures of 
ammomacal solution of 97 sp gravity, are 
just sufficient to saturate these Whence I 
adopt that solution as test ammonia, and con- 
clude that 100 grain measures of it contain 6 
grains of real ammonia 

It will be perceived, then, that the accuracy 
of the ensuing table depends upon t>everal 
points namely, whether 100 measures of mu- 
riatic acid of 1 074, really contain 11 grams 
of acid , whether the specific gravities of mu- 
riatic acid gas, and a(nmonu%.al gas, are really 
1 23 and 6, or in that ratio , and whether 11 
measures of acid gas saturate 12 measures of 



422 



K\DR()GEN WITH 



ammomacal gas I believe the errors in any 
of these particulars to be very small, and pro* 
bablv they may be such as partly to correct 
each other 

I find, after Mr Davy, that a measure of 
water being put to a measure of ammomacal so- 
lution, the two occupy two measures, without 
any sensible condensation , consequently, if the 
quantity of ammonia in a measure of any given 
specific gravity, as 90, be determined , then 
the quantity ma measure of 95, will be just half 
as much Hence, a table is easily constructed 
for measures, and one for weights is derivable 
without much calculation 

Table of the (juantities of reil or gaseous ammonia in so- 
lutions of different specific giatities 



ffic gra 

Af 


Crams of ammo 
ma in 100 water 
gram measures 
of li juid 


Critnt of ammo 
ma n 100 grains 
of liquid 


Soiling pbint 
of the liquid 

old scale 


Volume of g* 
co idensed In t 
gwen volume t>! 
liqu.d 


*) 


jO 


35 3 


26 


494 


PO 


2& 


J20 


^ 9 


456 


87 


2o 


299 


50 


419 


S8 


24 


27 J 


62 


382 


8Q 


22 


21-7 


7J- 


HO 


00 


20 


222 


86 


311 


91 


18 


198 


98 


277 


92 


1 10 


17 4 


110 


244 


9* 


14 


15 1 


122* 


211 


94 


12 


128 


134 fl 


180 


93 


10 


10 5 


146* 


U7 


96 


8 


8 3 


158* 


116 


97 


6 


t>2 


173 


87 


98 


4 


4 1 


Ib7<> 


57 


9<J 


Q 


(2 


196 


28 



AMMONIA 423 

On the above table, it mav be nroper to re- 
mark, that I have not had large quantities of 
ammomacal solution lower thar 94 ? so as to 
find their specific gravities experimentally j 
but have had small quantities to the amount of 
1O or 20 grains of the several solutions from 
26 to 12 per cent , I have no reason to sus* 
pcct any material deviation from the law of 
descent observed m the specific gravity down 
to 12 per cent , when we go below that num- 
ber , at all eventb, it cannot be great down 
to 85, and at is not of much importance, be- 
cause solutions of that strength are never ob- 
tained m the large way The second column, 
exhibiting the grams of ammonia m 100 mea- 
sures of the solution, is more convenient for 
practice than the third, which gives the 
weight in 100 grams of solution The fourth 
column, which shews the temperature at 
which the several solutions boil, will be found 
highly interesting The ebullition of a liquid 
is well known to take place, when the steam 
or vapour from it is of the same force as the 
atmospheric pressure In solutions down to 
J 2 per cent , the experiments were performed 
by inserting a thermometer into a phial con- 
taining the solution, and plunging the phial 
into hot water till the liquid boiled $ but m 
the higher solutions a bmall portion, as 20 



42* HYDROGEN WITH AZOTE 

grains, was thrown up a tube filled with mer- 
cur} 3 the tube was then put into a phial of 
mercurv, and the whole plunged into warm 
water , the temperature was then ascertained 
requisite to bring the mercury in the tube to 
the level of that in the phial The fifth co- 
lumn is calculated from the second, sup- 
posing the specific gravity of atnmoniacal gas 

=r 6 

It may bo observed, that the above table 
gives the quantity of ammonia in different so- 
lutions, from 15 to 20 per cent less than Mr 
Davy's table , also, that the common ajnmo- 
niacal solutions of the shops usually contain 
from 6 to 12 per cent of ammonia 

Before we can estimate the value of the 
fourth and fifth columns of the table, we must 
ascertain the force of vapour from ammomacal 
solutions at different temperatures If it be 
found in some one instance, we may by ana- 
logy infer the results in others As the steam 
from water vanes in force in geometrical pro- 
gression to equal increments of temperature, 
it might be expected that the steam or gas 
from liquid ammonia should do the same , but 
as the liquid is a compound, the simple law 
of the force of aqueous steam does not obtain 
It appears, however, from the following re- 
sults, that a near approximation to this law is 



AMMONIA 425 

observed Into a syphon barometer I threw 
a quantity of .946 liquid ammonia, which 
was by agitation, &c transferred to the va- 
cuum over the mercury The vacuum was 
then immersed successively m water of different 
temperatures, and the force of the gas observed 
as under, 

Temperature 

Force of amraom* 

old scale new scale differences acal steam from 

liquid 946 

140 151' 30 inch, 



1O3 6 115* J5 

31* 

74 84 7 5 

29 
50" 55 3 75 

Hence it seems, that the intervals of tempe- 
rature required to double the force of ammo- 
niacal steam, increase in ascending I had 
no doubt but this sort of steam or gas, would 
mix with common air, without having its elas- 
ticity affected, like as other steams do , but I 
ascertained the fact by experiment Thus I 
mixed a given volume of air with steam of 15 
Inches force, and found that the air was doubled 
in bulk 

These facts are curious and important They 
shew that ammonia is not retained in water 



426 HYDROGEK WITH AZOTE 

without external force, and that the pressure 
of no elastic ftuid avails but that of ammo- 
niacal gas itself , thus establishing the truth of 
the general law which I have so much insisted 
on, that no elastic fluid is a sufficient barrier 
agaitist the passage of another elastic ftuid 

We may now see upon what causes the 
saturation of water with ammonia depends 
They are two , the temperatw e of the liquid , 
end the pressure of the incumbent ammomacal 
gas, exclusive of the air intermixed with it. 
For instance, if the temperature be given, 50 
(old scale) ; then the strongest possible solu- 
tion, under atmospheric pressure, will be such, 
that 100 measures will have the specific gravity 
87, and contain 26 grains of ammonia, or 
419 times the volume of gas But if, in satu- 
rating the water by sending up gas, there be 
common air, so as to make ^-ths of the in- 
cumbent gas, then the solution cannot be marie 
stronger than 94-6, of which 100 measures 
contain 11 grains ot ammonia, or 162 times 
the volume of gas I ha\e obtained a satu- 
rated solution containing 26 per cent ammo- 
nia, with T f T th common air in the incumbent 
gas , and at the same temperature, another 
saturated solution, containing only 17 percent 
ammonia, with |th& common air in the in- 
cumbent gas 



AMMOKIA 427 



With respect to the constitution of ammonia, 
Priestley, Scheele and Bergman pointed out 
the two elements into which it is decomposed 
Bertholtet first settled the proportions of the 
dementb, and the quantity of each obtained 
from a given volume of ammomacal gas It 
is highly to his credit too, that subsequent 
repetitions of his experiments, under the im- 
proved state of knowledge, have scarcely 
amended his results Priestley resolved 1 mea- 
sure of ammomacal gas, by electricity, into 3 
measures of gas not absorbable by water , but 
his ammonia could not have been dry Ber- 
thollet resolved 17 measures into S3 m the 
same way this, result has since been corro- 
borated hv various authors He also found 
that the gas so produced, was a mixture of 12 1 
parts of azote by weight, with 29 of hydrogen , 
or 4 azote with 1 of h)dragen 

In 1800, Mr Davy published his researches, 
in which were given several interesting results 
on ammonia, Mr Davy decomposed ammo- 
nia, by sending the gas through a red hot 
po celain tube , after the common air was ex 
pelted, the collected gas was found free from 
oxygen To 140 measures of this gas were 
added 120 of oxygen , the mixture being ex- 
ploded by electnutv, 1 1 measures of gas v\ e*t? 
left and ot course 15O *ere cet ur'ed mt 



428 HYDROGEN WITH AZOTE 

water , of this 100 measures must have been 
hydrogen Whence, 140 measures of the gai 
from decomposed ammonia, contained 100 hy* 
drogen and 40 azote , or 100 measures con- 
tained 71 4 hydrogen and 286 azote This 
conclusion Was so nearly agreeing with the 
previous determination of Berthollet, that both 
have justly been held up as specimens of the 
accuracy of modern chemical analysis 

In 1808, Mr Davy published his celebrated 
discoveries relating to the decomposition of 
the fixed alkalies Having ascertained that 
these contained oxygen, he was led by analogy 
to suspect the same element in ammonia Se- 
veral experiments were made, which seemed 
to countenance this idea , but these could not 
be considered conclusive, as long as it wa* ad- 
mitted that no oxygen appeared in the decom- 
position of ammonia by electricity, and yet 
that the weight of the azote and hydrogen 
were togethci equal to that of the ammonia 
decomposed Mr Davy le-examined the spe- 
cific gravity of ammomacal gas, the quantity 
of gases evolved by the decompobition of a 
given volume of it, and tnc ratio of azote to 
hydrogen in the same I he result was, that 
the gases obtained amounted only to 4-^ths of 
the weight of the ammonia , the remaining 
-rVth Mr Davy thoight mubt be oxygen, 



AMMONIA. 429 

\vtuch, uniting to hydrogen, formed a portion 
of water The way in which this ^th was 
saved, was principally by diminishing the ab- 
solute quantity of gases derived from a given 
volume of ammonia, but partlv by finding less 
azote and more hydrogen than had been before 
estimated Thus, 100 measures of animo- 
niacal gas produced only 180 measures of 
mixed gas, though commonly estimated at 200, 
and this gas was found to consist of 26 azote 
and 74 hydrogen per cent 

These conclusions, so different from what 
had been long adopted, and depending upon 
experiments of s^me delicacy, were not likely 
to be received without a more general scrutiny 
Dr Henry in England, and A B Berthollet 
jn France, seem both to have renewed the 
investigation into the component parts of am- 
monia with great care and assiduity Dr 
Henry's object was to determine whether an] 
oxygen, water, or any other compound con 
taming oxygen, could be detected in the ana* 
lysis of ammonia , this enquiry included the 
two others, lamely* the quantity of gases ob* 
tamed from a given volume of ammomacal 
gas, and the proportion of a^ore to hydrogen 
in the same I he results were, that neither 
oxygen nor water could be found , that for the 
most part the bulk of ammonia was doubled 



430 HYDROGEN WITH AZOTE 

by decomposition, even vrhen the gas was 
pieviously dried with extreme care , and that 
the ratio of azote to hydrogen m the mixture, 
from an average of six careful experiments* 
was 27^ to 72|- In this last decision, Dr 
Henry was so fortunate as to discover a more 
easy and expeditious mode of analysis than 
had been known before > he found that am- 
momacal gas mixed with a due proportion of 
oxygen, of nitrous oxide, or even of nitrous 
gas, would explode by an electric spark He 
found an under proportion of oxygen gas to 
answer best (about 6 measures of oxygen to 1O 
of ammonia) the explosion produced a com- 
plete decomposition of the ammonia, and a 
partial combustion of the hydrogen , after 
which more oxygen was put to the residuum, 
and the remainder of the hydrogen consumed 
From one experiment, in which 100 measures 
of ammonia were decomposed in a tube of 
which the mercury had been previously boiled, 
Dr Henry only obtained 181 measures of gas , 
and he seems to think that this experiment 
may be the most correct in regard to that 
object (Philos Trans 1809) 

In the Memoires d'Arcueil, torn 2, M A 
B Berthollet has a paper on the analysis of 
ammonia He alludes to the experiments of 
m the memoirs of the academy 



AMMONIA 431 

1785 > in which the ratio of 27 5 azote to 72 5 
hydrogen, was found m the decomposed av 
tnonia, allowing 196 hydrogen for 100 oxygen 
He reports several experiments and observa- 
tions felatwe to the oxidation and deoxidatioft 
of iron in ammomacal ga* He then proceeds 
to prove, that the weight of azote and hydro- 
gen produced in the decomposition of am- 
monia, is equal to the weight of the ammonia 
itself Biot and Arago determine the specific 
gravities of azote, hydrogen^ and ammonia, 
to be 969 078, and 597 respectively, which 
A B Berthollet adopts He finds that 100 
measures of ammonia produce 205 of perma- 
nent gas , which, by analysis,, gives 24 5 azote 
and 75 5 hydrogen per cent Like Dr Henry, 
A B Berthollet decomposed ammonia by ex- 
ploding it with oxygen gas , but unfortunately 
he used an excess of oxygen, and then deter- 
mined the residuary oxygen by the addition of 
hydrogen he was aware, however, that part 
of the azote was thus converted mto nitric 
acid Upon collecting the results, he makes 
it appear, that the gases produced by the de- 
composition of ammonia are, as nearly as pos- 
sible, equal to the weight of the ammonia 

Though the experiments of these two au- 
thors may be deemed satisfactory, with regard 
to the non-existence of oxygen m ammonia, 



432 HYDROGEN WITH AZOTE 

they would have been more so if they had 
accorded m the quantity of gas derived from a 
guen volume of ammonia, and in the ratio of 
azote to hydrogen Having made some expe- 
riments myself on these heads, I may be al- 
lowed to give my opinion as to the causes of 
these differences I am persuaded, with Mr. 
Davy, that ammonia is not doubled by decom- 
position, when due care is taken to prevent 
any liquid from adhering to the tube or mer 
cury, but at the same time am inclined to 
believe, from experience, that 100 measures 
of ammonia will give not less than 185 or 190 
measures of gas by dscomposition I took a 
tube and filled it with dried mercury 3 then 
transferred a portion of gas into it, and by 
pushing a glass rod up the tube several times, 
displaced the mercury in the tube, so that no 
liquid ammonia could exist in the renovated 
mercury This gas, being decomposed by 
electricity, produced after the rare of 1 87 for 
100 With respect to the ratio of azote to 
hydrogen, I am convinced it is to be obtained 
only by decomposing the ammonia previously 
to the combustion of the hydrogen, and this 
may be done either by electricity or by heat , 
in these cases, ammonia will be resolved into 
28 measures of azotic gas, and 72 measures of 
hvdropen gas m the hundrt-ci I have re- 



AMMONIA 433 

peatedly obtained it so by electricity, the re* 
suits never deviating farther than from 27 to 
29 of azote This agrees sufficiently with 
Berthollet's original analysis by electricity, 
and with Davy's analysis by heat m 1800, 
both of them made without any theoretic 
views as to quantity, which cannot be said of 
any of the subsequent investigations on this 
subject 

A\ e are now to see how far these results 
will agree with the specific gravity of ammo- 
niacal gas that is, whether the weights of the 
two gases are equal to the weight of the am- 
monia decomposed 

Gums 

loo measures of ammonia, which X sp gr 6 gives 60 
become 185 measures of mixed gas, .. 

namely, 5! 8 azote, which X *p gr 967 givet 50 09 
and 133 a hydrogen, which X sp gr o? gives 1065 

6074 

The excess of ^thsof a giam upon 60, is too 
small to Tient notice, and may arise from an 
inaccuracy in any of the data, which, if cor- 
rected, could have no material influence on the 
conclusions 

I shall now make a few observations on the 
other methods of analyzing ammonia Dr. 
Henry's methods of burning ammonia in 

Vnlf-a'c ^iiHmmptpr nlnnor with 



43* HYDROGEN WITH AZOTE 

nitrous gas, and nitrous oxide, umte elegance 
with expedition, and when well understood, 
cannot but be valuable It appears to me, 
however, both from experience and analogy, 
that a compound combustible, such as am- 
monia, is never decomposed and one of its 
elements burnt, to the entire exclusion of the 
other Numerous instances may be found m 
the compounds of charcoal and hydrogen, of 
phosphorus and hydrogen, fee where one of 
the elements seizes the oxygen with more ra- 
pidity than the other , but some portion of the 
other is always burnt Even when the com- 
bustible gases are only mixed together, and 
not combined, we do not find that one of them 
precludes the other from taking a share of *he 
oxygen till it is saturated Thus, in a mixture 
of carbonic oxide with hydrogen, with a defi- 
ciency of oxygen, part of both is burnt by an 
electric spark Dr Henry has, indeed, no- 
treed that ammonia fired with excess of oxy- 
gen, gives nitric acid as well as water I have 
reason to believe this is the case in some de- 
gree, m whatever proportion they are fired* 
I have seldom obtained so much ai> 27 per 
cent of azote by the combustion of ammonia 
with oxygen (the hydrogen being estimated by 
doubling the oxygen spent;, and in no in- 
stance 28 but it will be manifest that all the 



AMMONIA 435 

oxygen is not consumed m burning the hydro- 
gen, if we note the ammomacal gas expended, 
and allow only 66 or 67 per cent oxygen for 
the hydrogen , there will generally be found a 
greater expence of oxygen, which must have 
gone to form nitric acid The combustion of 
ammonia with nitrous gas usually gives from 
25 to 27 per cent, of azote, allowing the con- 
stitution of nitrous gas to be what is stated at 
page 331 Upon the whole, 1 found nitrous 
oxide to approximate nearest to the truth 
When 100 measures of ammonia are exploded 
with 120 of nitrous oxide, the gases resulting 
are azote with a very small portion of hydro- 
gen , if to this a little hydrogen be added, and 
then an excess of oxygen, another explosion 
will determine the residuary hydrogen , uhich 
being deducted, there remain about 172 azote, 
120 of which come from the nitrous oxide, 
and 52 from the ammonia, which gives after 
the rate of 28 azou per cent on the evolved 
gases When the decomposition of arrmonia 
i* attempted by oxymunatic acid gas, a gra- 
duated tube is filled wuh the gas, ana plunged 
into liquid ammonia in this way, if we 
reckon a measure of the acid gas to a measure 
of hydrogen, we shall find the azote evolved 
and left in the tube, amount to 23 or 24 per 
cent upon both gases It is to be presumed, 



436 HYDROGEN WITH AZOTE 

then, tha, oxymunatic acid, like oxygen, 
consumes part of both the elements of am- 
monia 

By comparing the weight of azote with that 
of hydrogen in the above table, we find them 
is 4 7 to 1 nearly This evidently marks the 
constitution of ammonia to be that of I atom of 
each of the elements combined But we have 
before determined the element of azote to 
weigh 5 1, when treating of the compounds of 
azote and oxygen This difference is probably 
to be ascribed to our having over-rated the 
specific gravity of nitrous gas, and perhaps 
nitrous oxide f In the Alemoires d}Aracczl> I 
observe Berard finds the specific gravity of ni- 
trous gas to be 1 04, instead of 1 10, which 
last I have made my calculations from , if the 
former should prove true, it will reduce my 
valuation of azote m nitric acid nearly to 4 7 , 
I have not had an opportunity of ascertaining 
the specific gravity of nitrous gas , but am in- 
clined to believe that 1 10 may be too high 
Berthollet finds nitrous oxide to be 1 36, in- 
stead of 1 6 1 , 1 much suspect the former is too 
low 

Upon the whole, vie may conclude that an 
atom of ammonia \s constituted of 1 atom of 
hydrogen and 1 of azote, and weighs nearly 6 
The diameter of the elastic particle is 909, 



OLEFIANT GAS 437 

that of hydrogen being 1 Or, 300 measures 
of ammoniacal gas contain as many atoms as 
400 measures of hydrogen, or as 200 of 
oxygen 



SECTION 7 

HYDROGEN WI1H CARBONF 

There are two combinations of hydrogen 
with carbone, now well known, easily dis- 
tinguishable from each other and from all other 
combinations The} are both elastic flutdb , 
one of them, called olefiant gas, is a compound 
of 1 atom of hydrogen and 1 of carbone , the 
other, which I call carburetted hydrogen, is 
a compound of 2 atoms of hydrogen and 1 
of carbone, as will be manifest f r om what 
follows 

J Olefiafit Gas 

The gas denominated ole//anf, was disco- 
\ered and examined by t'ie Dutch chemists, 
Bondt, Dicman, &,c and a memoir on the sub- 
ject was published in the 15thvol of the Jour- 
nal de Ph}sique, 17<H 



HYDROGEN WITH CARBONE* 

Olefiant gas may be procured by mixing 2 
measures of sulphuric acid with 1 measure of 
alcohol , this mixture in a gas bottle must be 
heated to about 300 by a lamp, when the 
liquid exhibits the appearance of ebullition, 
and the gas comes over * it should be passed 
through water, to absorb any sulphurous acid 
which may be generated 

This gas >s unfit for resptratroo, and extin- 
guishes flame, but it is highly combustible 
its specific gravity, according to the Dutch 
chemists,, is .905 , according to Dr Henry, 
#67* Perhaps 95 5s about the truth Water 
absorbs -th of its bulk of this gas , or the atoms 
of gas in the water are just twice the distance 
they are without , and it may be expelled 
again by the othe^ gases This property (of 
being absorbed by 8 times its bulk of water) 
occurred to me in 1 804, in a course of expe- 
riments on the absorption of gases bv water. 
It is peculiar to this gas, and consequently 
distinguishes it from all others When olefiant 
gas is mixed with oxymunatic acid gas, a di- 
minution takes place, like as when oxygen 
and nitrous gas are toixed , but the result is 
&n oil, which swims on the surface of the 
water Hence the Dutch chemists gave this 
gas the name of olefiant For this purpose, 
they found 3 measures of olefiant gas required 



OLEFIANT GAS 430 

4 measures of the acid gas , but Dr Henry 
finds 5 of olefiant require 6 of the acid The 
difference is not great, considering the diffi- 
culty of the experiment As neither of these 
results will agree with the other known pro- 
perties of these two gases, I suspected that 
both would be found m some degree incorrect; 
which proved to be the case from the follow* 
ing experiments Having; taken two similar 
tubes graduated, containing each about 170 
grains of water, I filled them, one immediately 
after the other, from a bottle generating oxy- 
munatic acid copiously , into one of these, 
200 measures of olefiant gas were slowly trans- 
ferred , after standing some time, the residuary 
gas was transferred and noted , then the other 
tube with acid gas was taken, the gas passed 

5 or 6 times through water, till no further di- 
minution was observed, and the residuary gas 
was noted and allowed for impurity in the first 
tube By this procedure no acid gas was lost, 
and an excess of olefiant gas being used, the 
purity of this last did not enter into the calcu- 
lation In one trial, 165 measures of oxymu- 
riatic acid gas condensed 16H of- olefiant gas , 
in another, 165 took 167 From these, I 
conclude that oxymunatic acid requires a very 
little more than its bulk of olefiant gas to be 
saturated perhaps 100 of the former may take 



440 HYDROGEN WITH CARBONE. 

102 measures of the latter , but if we reckon 
equal volumes, the error cannot in general be 
material 

Olefiant gas burns with a dense, white 
flame It explodes with uncommon violence 
when mixed with oxygen and electrified , the 
products resulting are various, according to the 
circumstances When completely saturated 
with oxygen, the results are, according to 

erb aci4. 

Berthollet, 100 measures take 280 oxygen, produce 180 
Dr Henry, 100 284- 179 

The rest of the produce is water These 
results, agreeing so well with each other, are 
the more plausible , but I can add that my 
own experience corroborates thejn, particu- 
larly m regard to oxygen My results have 
always given less than 300, but more than 270, 
the acid, I apprehend, should be about J85 
or 190 unless a great excess of oxygen be 
used, the charcoal is partly thrown down, and it 
makes the gas turbid after the explos on , the 
result in this case affords less carbonic acid 
than is due 

When olefiant gas alone is subjected to con- 
tinued electricity, either over mercury or wa- 
ter, the result is hydrogen gas, and a quantity 
of charcoal is deposited A very careful ex- 
periment of this kind was made by Dr Iknry 



OLEFIANT G\*. 441 



and myself, in which 42 measures of pure 
olefiant gas were electrified till they became 
82 , these were exploded with oxygen, and 
found to consist of 78 hydrogen, and 2 ole- 
fiant gas Here 40 olefiant became 78 hy- 
drogen, or very near double The charcoal 
was thrown down According to this, 100 
measures of olefiant gas will contain 193 of 
hydrogen , which require 98 oxygen for their 
combustion , now as the charcoal must take 
the rest, or nearly 196 measures, it follows that 
m the combustion of olefiant gas, 2 parts of 
the oxygen are spent upon the charcoal, and 1 
part upon the hydrogen Hence we obtain 
this conclusion, that an atom of olefiant gas 
consists of 1 of charcoal and 1 of hydrogen 
united No oxygen can be present in olefiant 
gas , because during the elec rification it would 
be detected, either m the form of water or 
carbonic oxide 

It will be proper now to see how far the 
weights of the gases entering into combination, 
agree with the previous determinations An 
atom of charcoal weighs j 4 (see page 382), 
and 1 ofhvcliogen \\eiqhs 1, together making 
an atom of defiant gas, 64 1 his atom \\ill 
require 3 of oxjgcn for its combustion , 
namel), 2 for the charcoal, to foim carbonic 
atid, and 1 for the hvdrogcn, to form water, 



442 HYDROGEN WITH CARBONE 

these 3 weigh 21 , whence 6,4 parts of olefiant 
gas by weight, should take 2L of oxygen 
Now supposing, according to Dr Henry'* re- 
salt, that 100 measures of olefiant gas require 
284 for thetr combustion , and further, that 
the specific gravity of oxygenous gas is 1 10 
(agreeably to Allen and Pepys, as also Biot 
and Arago), we shall have 284 X i i = 312 4, 
the weight of the oxygen , hence, if 21 6.4 : 
3124 95, the weight of 100 measures of 
olefiant gas, corresponding to a specific gravity 
of 95 Hence, then, it appears that the 
weight of the gases combined, perfectly corro- 
borates the above conclusions respecting the 
constitution of olefiant gas 

There are some remarkable circumstances 
attending the combustion of olefiant gas in 
Volta's eudiometer, which deserve notice as 
part of the history of the gas, but particularly 
as they put the constitution of the gas beyond 
all doubt If 100 measures of oxygen be put 
to 100 of olefiant gas, and electrified, an ex- 
plosion ensues, not very violent , but instead 
of a diminution, as usual, there is a great 
increase of gas, instead of 200 measures, there 
will be found about 360 , some traces of car- 
bonic acid are commonly observed, which dis- 
appear on passing two or three times through 
litne water, there will then remain, perhaps, 



OLEFIANT GAS. 443 

350 measures of permanent gas, which is all 
combustible, yielding by an additional dose of 
oxygen, carbonic acid and water, the same as 
if entirely burnt in the first instance What, 
therefore, is this new gas in the intermediate 
state ? The answer is clear It is carbonic 
oxide and hydrogen mixed together, an equal 
number of atoms of each One third of the 
oxygen requisite for the complete combustion, 
suffices to convert the carbone into carbonic 
oxide, and the hydrogen at the instant is li- 
berated , hence the other two thirds are em- 
ployed, the one to convert the carbonic oxide 
into acid, the other to convert the hydrogen 
into water In fact, the 350 measures consist 
of nearly 17O of each gas, which together re- 
quire nearly 17O of oxygen for their com- 
bustion * 

* M Bert hoi let contends, that all the combustible gases 
into which carbooe and hydrogen enter, contain also oxy- 
gen he calU them oxycarburetud hydrogen Mr Murray 
also enters into his views in this respect As fir as relates 
to olefiant ga, it will be time enough for animadversion 
on this opinion, when- the accuracy of the above facts and 
observations aie questioned But there is one circumstance 
which M Jkrthollet has not explained in regard to this 
gis, and it turns upon a point which he and I acknowledge, 
but \frhith is not perhaps generally received, namely, that 
when 1 10 gates unite tojorm a third, this las<t u specifically 
than the lighter of the two Now, in the above 



444 HYDROGEN WITH C1RBONE 

The diameter of an atom of olefiant gas is 
.81 to hydrogen J And 100 measures of it 
contain as many atoms a* 188 of hydrogen, or 
as 94 of oxygen, or (probably) as 200 of oxy- 
murutic acid , whence the union of this last 
with olefiant gas, must be 2 atoms of the gas 
with 1 of the acid 



2 Carlmrettcd Hydrogen 

The gas which I denominate carburetted 
hydrogen, was known in a state of mixture, 
to Dr Priestley , he called all such mixtures 
by the name of heavy inflammable an La- 
voisier, Higgins, Austin, Cruickshanks, Ber- 
thollet, Henry and others, have since culti- 
vated this department of science Cruick- 
shanks contributed much to unveil the subject, 
by pointing out carbonic oxide as an inflam- 
mable gas, sm gene7is, but often found mixed 
with other gases No correct notion of the 
constitution of the gas about to be described, 
seems to have been formed till the atomic 

instance, we find olefiant gas and ox}genous gas, uniting 
to toon a thud (according to his opinion), which, is lightei 
by owe halt neaily thin the lighter ot the two How is 
this new oxycarburettcd hydrogen to be ictonciltd with 
tht above principle * 



CAKBURFTTED HYDROGEN 

theory was introduced and applied in the in- 
vestigation It was in the summer of 18(H, 
that I collected at various* times, and in various 
places, the inflammable gas obtained from 
pocwk, this gas I found always contained some 
traces of carbonic acid and a portion of azote, 
but that when cleared of these, it was of a 
uniform constitution. After due examination, 
I was convinced that just one half of the oxy- 
gen expended in its combustion, in Volta's 
eudiometer, was applied to the hydrogen, and 
the other half W the charcoal This leading 
fact afforded a clue to its constitution 

Carburetted hydrogen gas may be obtained 
in a pure state, with the above exceptions, 
from certain ponds in warm weather Clayey 
ponds, in the vicinity of a town, where soot 
and other carbonaceous matter is deposited, 
abound with this gas The bottom of the 
pond being stirred with a stick, large bubbles 
ascend, which may be caught by filling a 
tumbler with water, and mveitmg it over the 
ascending bubbles This gas is obtained nearly 
pure also by distilling pitcoal with a moderate 
red heat It is now largely used as a substitute 
foi lamps and candles, under the name of coal 
gay According to Dr I Lmy's analysis, coal 
gas aoes not usually contain more than 4 or 5 
percent of carbonic acid, sulphuretted h)dro- 



446 HYDROGEN WITH CARBO3TE, 

gen, and olefiant gas The rest is principally 
carburetted hydrogen, but mixed with some 
atoms of carbonic oxide ami hydrogen The 
last portion of gas driven off from pit-coal, 
seems to be entirely carbonic oxide and hydro- 
gen. The distillation of wood and of moist 
charcoal, and many other vegetable substances, 
produces carburetted hydrogen, but highly 
charged with carbonic acid, carbonic oxide 
and hydrogen , the two last gases always appear 
exclusively at the end of the process 

The properties of carburetted hydrogen are r 
I It is unfit for respiration, and for the sup- 
port of combustion 2 Its specific gravity 
when pure, from my experience is very near 
6 Dr Henry finds the coal gas to vary from 
,6 to 78 , but then the heaviest contain 15 
per cent of the heavy gases, carbonic acid, 
sulphuretted hydrogen, and olefiant gas 
Water absorbs T T T ^ of its bulk of this gas If 
100 measures of carburetted h}diogen be 
mixed with 100 measures of oxygen (the least 
that can be used with effect), and a spark 
passed through the mixture, there is an ex- 
plosion, without any material change of vo- 
lume after passing a few times through lime 
water, it is reduced a little, manifesting signs 
of carbonic aciJ This residue is found to 
posses* all the characters of a mixture of equal 



CARBUfcETTEB HYDROGEN, 447 

volumes of carbonic oxide and hydrogen* 
Upon adding 100 measures of oxygen to this 
residue and passing a spark, nearly 100 mea- 
sures of carbonic acid are produced, and the 
rest of the produce is water If 100 measures 
of carburetted hydrogen be put to upwards of 
200 of oxygen, and fired over mercury, the 
result will be a diminution of near 200 mea- 
sures, and the residuary 100 measures will be 
found to be carbonic acid 

Though carburetted hydrogen is naturally 
produced in many coal mines, and occasionally 
mixing with common air, exhibits some dread- 
ful explosions w the large way, yet when 
mixed with common air, in Volta's eudio- 
meter, it does not explode by a spark, unless 
the gas be to the air, as 1 to 10 nearly, and 
then feebly 

When a portion of carburetted hydrogen gas 
is electrified for some time, jt increases in 
volume, in the end almost exactly doubling 
itself , at the same time a quantity of charcoal 
is deposited The whole of the gas is then 
found to be pure hydrogen 

All these facts being compared, there can- 
not remain the least doubt as to the constitution 
of carburetted hydrogen It is a compound 
of one atom of charcoal and two of hydrogen , 
the compound atom occupies the same space 



448 HYDROGEN WITH CARBONE, 

(nearly) as an atqm of hydrogen , and 4 atoms 
of oxygen are necessary to its complete com- 
bustion , namely, 2 for the charcoal to form 
carbooic acid, and 2 for the hydrogen to form 
water. This conclusion derives a vei) elegant 
confirmation, from the facts observed by ex- 
ploding the gas with one half of the oxygen 
requisite for complete combustion In this 
case, each atom of the gas requires only 2 
atom*; of oxygen^ the one joins to one of hy- 
drogen and forms water , the other joins to 
the carbone to form carbonic oxide, at thfc 
same moment the remaining atom of hydrogen 
springs off Thus there becomes 100 measures 
of carbonic oxide and 100 of hydrogen, or the 
same bulk as the original mixture 

As the weight of an atom of charcoal is 5 4, 
and 2 atoms of hydrogen are 2, the compound 
atom weighs 7 4 , but as there are the same 
number of atoms of hydrogen and of carbu- 
retted hydrogen in the same volume, 7 4 repre- 
sents the number of times that carburettul 
hydrogen is heavier than hvdrogen Now, the 
weight of common air is about 12 times as 
great as hydrogen j therefore, the relative 
weights or specific gravities of the two gases, 
are as 7 4 to 12, or as 6 to 1, nearly, which 
agrees with experience , hence we derive this 
conclusion, that carburetted hydrogen consists 



CARBTTfcETTED HYDROGEN 449 

/entirely of hydrogen and carbone, the whole 
weight of the gas being accounted for in the 
carbonic acid and water formed by its con> 
bustion * 

I think it proper to observe, that, according 
to my most careful experiments, 100 measures 
of this gas require rather more than 200 niea- 

* According to M Beithollet (IVJera d'Arcueil, tome 2d) 
the gas from charcoal is a tuple, compound of carbone, 
oxygen, and hydrogen Whatever our speculative che- 
mists may believe, no practical chemist in Britain adopts 
Uiio idea That it always contains more ,or less of oxygen 
no one disputes , but then the oxjgen is united solely to 
the carbon e forming carbonic oxide The rest of the mix- 
ture consists of carburetted hydiogen and hydrogen I 
never find any difficulty in ascertaining the relative quan- 
jtities of each of the gases in such mixtures For instance, 
suppose we take the first of Berthollet's ume specimens 

100 gas sp gr 462 took 81 oxy gave 56 carb acid* 



SOcaib hyd sp gr 6 takes 42 gives 21 

34nrb ox 9t 16 32- 

46hvd OS 23 



JOO rnixt 476 takes 8J gives 53 



Here it ippr *s, that 20 measuics of carb hyd + 34 
carb oxide + 40 hydrogen, constitute a mixture of 100 
measurts ofthesp gnv 476, which hung burned, take 
81 o\y^n, and guc 53 carb icid Hence this mixture 
may bL consi It red ns agreeing with Btrtholkt'* gis from 
charcoal above specified 



450 HYDROGEN WITHSUJFIiUR 

sures of oxygen, and give rather more than 
100 carbonic acid , but the difference is not 
more than 5 per cent and may in general be 
neglected Hence, then, we may conclude 
that the diameter of an atom of carburetted 
hydrogen is nearly equal to that of hydrogen, 
but rather less 

SECTION 8 
HYDROGEN WITH SULPHUR 

There are two compounds of hydrogen with 
sulphur , the one, a well known elastic fluid 
denominated sulpkiu etted hydrogen, the other 
a viscid, oily compound, called supei sulphu- 
retted hydrogen The former of these consists 
of 1 atom of each element,* the the latter pro- 
bably of 1 atom of hydrogen united to 2 of 
sulphur 

1 Sulphuretted llydiogen 

The best way I have found to ob f am sul- 
phuretted hydrogen in a pure state, is to heat 
a piece of iron to a white or welding heat in a 

* Tbt* figure for sulphuretted hylio^cn, platt J-, part I, 
is incorrect it ought to be 1 itom of hydiogpn instead oi 8, 
united to I ot sulphur 



SULPHURETTED HYDROGEN. 45l 

smith's forge, then suddenly drawing it from 
the fire, apply a roll of sulphur, the two being 
rubbed together, unite and run down in a 
liquid form, which soon fixes and becomes 
brittle This compound or sulphuret of iron, 
is to be granulated and put into a gas bottle, 
to which dilute sulphuric acid is to be added, 
after which the gas comes over plentifully 
When the sulphuret of iron is made in a cru- 
cible from iron filings and sulphur, it seldom 
answers well , it often gives hydrogen mixed 
with the sulphuretted hydrogen The reason 
seems to be, that several sulphurets of iron 
exist , namely, the first, the second, the third, 
&c and it is the second only, or that which is 
constituted of I atom of iron and 2 of sulphur, 
formed in the process above described, which 
ts essential to the formation of sulphuretted hy- 
drogen The others either give hydrogen or 
no gas at all 

Sulphuretted hydrogen is unfit for respiration 
and for supporting combustion it has a disa- 
greeable smell, resembling that of rotten eggs , 
its specific gravity is 1 10 according to Kirwan, 
and 1 23 according to Thenard Mr Davy f 
I understand, makes it about 1 IS Some trials 
of mine a few years since, gave a result near 
Fhenatd's , but till a more correct one can be 
obtained, we may adopt the mean 1 16 Wa- 



452 HYDROGEN WITH 

ter absorbs ju?t its bulk of this gas, 
therefore, rt is mixed with hydrogen, th<s last 
Will be left after washing in water, or wha 
is still better, m lime water Sulphure'tcd 
hydrogen burns wtth a blae flame- When 
mrxed with oxygen, in the ratio of 100 mea- 
sures to 50 of oxygen (which is the least ef- 
fective quantity), it explodes by an electric 
spark, water is produced, sulphur is depo- 
sited, and the gase* disappear If 150 or more 
measures of oxygen are used, then after the 
explosion over mercurv, about 87 measures of 
sulphurous acid are found in the tube, and 
150 of oxygen disappear, or enter into com- 
bination with both the elements of the gas 

From the experiments of Austin, Henry, 
&c it has been established, that sulphuretted 
hydrogen undergoes no change of volume by 
electrification, but deposits sulphur I have 
repeated these experiments, and have not 
been able to ascertain whether there was in- 
crease or diminution The residue of gas is 
pure hydrogen 

From these facts, the constitution of sul- 
phuretted hydrogen is clearly pointed out It 
is 1 atom of sulphur and 1 of hydrogen, united 
in the same volume as 1 of pure hydrogen 
When burned, 2 atoms of oxvgen unite to 1 
of sulphur to form sulphurous acid, and 1 of 



SCPERSTTLPHURETTED HYDROGEN. 453 

oxygen to 1 of hydrogen to form water The 
weights of the elements confirm this consti- 
tution One at6m of sulphur has been found 
to weigh ) 3 (see page 393), to which adding 
1 for hydrogen, we obtain the weight of an 
atom of sulphuretted hydrogen =14, this 
number likewise expresses the number of times 
that sulphuretted hydrogen should exceed hy- 
drogen in specific gravity But common air 
exceeds hydrogen 12 times , therefore, 12 : 
14 specific gravity of common air *p gra- 
vity of sulphuretted hydrogen =1 16, agree- 
ably to the preceding determination Hence 
this gas is wholly composed of sulphur and 
hydrogen, as above 

Sulphuretted hydrogen unites, like the acids, 
to alkalies, earths, and metallic oxides, form- 
ing with them salts of definite proportions, 
which are called hydrosulphm etv Some of 
thes^are important chemical agents, but thev 
are apt to undergo changes by keeping, espe- 
cially in solution 

2 Supcnulphur cited Hydrogen 

This compound maybe obtained as follows 
Let half an ounce of flower of sulphur and as 
much hydrate of lime, be gently boiled toge 
ther in a quart of ram water for one hour 



HYDROGEN WITH &t r LFHlTR. 

more water may be added as it evaporates 
After cooling, a clear yellow Irquid is ob* 
tamed, which is a solution of sulphuret of 
lime it will vary in specific gravity from I 01 
to 1 02, according to circumstances- To 6 
ounces of this liquid put half an ounce ot mu- 
riatic acid, and stir the mixture In a short 
time, the mixture exhibits a milky appearance* 
and this becomes interspersed with brown oily 
dots, which gradually subside into an adhesive 
tuass of a seouhquid form at the bottom The 
liquid may then be poured off, and the brown 
mass washed with water, which is to be 
poured off From 20 to 40 grains of this brown 
oily substance will be obtained y it is super- 
sulphuretted hydrogen. 

Scheele, BerthoJlet, and Proust, have made 
observations an this compound When ex- 
posed to the air, or even in water, it exhales 
sulphuretted hydrogen, especially if warm 
On account of its viscidity and adhesiveness, 
it is very difficult to subject it to experience 
If a portion of it touch the skin, &c it requires 
a knite to scrape it off It may be poured 
from one vessel to another by means of wuter, 
which prevents its adhering to the vessel 
When a little of it is appphed to the tongue, a 
sensation of great heat, and a bitter taste arc 
felt , the saliva becomes white like milk 



SITPEHSULPHURETTED HYDROGEN 455 

When liquid alkali is poured upon supersul- 
phuretted hydrogen, heat is> produced, hydro- 
sulphuret is formed, and sulphur precipitated. 
These facts have all been observed by me, 
though few if any of them are new 

There is no doubt this substance is formed 
of sulphur and hydrogen I took 30 grams, 
and exposed them to a moderate heat in a 
glass capsule, ovei a candle, till they ceased to 
exhale sulphuretted hydrogen The residuum 
weighed 21 grains, it was soft hke clay^ 
when ignited, it burned away with a blue 
flame, and left no sensible residuum When 
it is considered, that supersulphuretted hy- 
drogen is from trie moment of its formation 
exhaling sulphuretted hydroigen, we cannot 
wonder that a portion of it should give less 
than half its weight of this gas But scarcely 
any doubt can be raised that the sulphur of 
the gas ^ originally equal to that left behind , 
or that supersulphuretted hydrogen is consti- 
tuted of 2 atoms of sulphur and 1 of hydrogen, 
and consequently weighs 27 times as much as 
hydrogen 

Though it is not our present business to ex- 
plain the previous process by which the article 
under discussion is obtained , yet, as it v\ill be 
some time btfoie it comes regularly in our 
way, it may pcihaps be allowable Hydrate 



4o6 HYPROGEN WITH PHOSPHORUS. 

of lime* is I atom of lime and I of wate? 
united , when boiled with sulphur as above, 
it takes 3 atoms of sulphur The compound 
is sulphur et of hydiate of lime When mu- 
riatic acid is mixed with it, the acid seizes the 
lime The ^ atoms of sulphur divide the atom 
of water in such sort, that two of them take the 
hydrogen to form super sulphuretted hydrogen, 
and one takes the oxygen to form sulphurous 
oxide This last occasions the milkmess of 
the liquid , by long digestion the milkmess 
vanishes the sulphurous oxide is changed into 
sulphuric acid and sulphur, which last falls 
down, and forms nearly one fourth of that 
which originally existed m the sulphuret 



SECTION 9, 

HYDROGEN WITH PHOSPHORUS 

There is only one combination of hydrogen 
with phosphorus yet known , it is a gas deno- 
minated photyhm cited In/chogep This gas 
may be procured as follows Let an ounce or 
two of hydrate of lime (dry slacked lime) be 
put into a gas bottle or retort, and then a few 
small pieces of phosphorus, amounting to 4O 
or 50 grains If the materials are sufficient tq 



PHOSPHURETTED mDROGEH 457 

fill the bottle, no precaution need be used 5 
but if not, the bottle or retort should be pre- 
viously filled with azotic gas, or some gas not 
containing ox)gen, in order to prevent an ex- 
plosion The heat of a lamp is then to be ap- 
plied, and a gas comes which may be received 
over water This gas is phosphuretted hy- 
drogen 5 but sometimes mixed with hydrogen 
Liquid caustic potash may be used instead 
of hydrate of lime, in order to prevent,, the ge- 
neration of hydrogen 

Phosphuretted hydrogen gas has the fol- 
lowing properties 1 When bubbles of it 
come into the atmosphere, they instantly take 
fire , an explosion is produced, and a ring of 
A*hite smoke ascends, which is phosphoric 
acid 2 It is unfit for respiration, and for 
supporting combustion 3 Its specific gravity 
is 85, ct>mmon air being denoted by unity 
4 Water absorbs / T th of its bulk of this gas 
6 If the gas be electrified, the phosphorus is 
thrown down, and there finally remains the 
bulk of the gas of pure hydrogen In fact, 
the phosphorus is easily throun down, either 
by electricity, by heat, or by being exposed 
to a large surf tee of \\itcr In this respect, 
phosphuretted hydrogen i* nearly related to 
sulphuretted h)drogen 

Though phosphuretted hydiogen e*plodes 



458 HYDROGEN WITH PHOSPHORUS, 

when sent into the atmosphere in bubbles, yet 
if sent into a tube of three tenths of an inch 
diameter, it maj be mixed with pure oxygen, 
without any explosion In all the experiments 
I have made, which are more than 20, I never 
had an instance of a spontaneous explosions 
In this case, an electric spark produces a most 
vivid light, with an explosion not very vio- 
lent , phosphoric or phosphorous acid and wa- 
ter are produced 

My experiments on the combustion of this 
gas give the following results When 100 
measures of pure phosphuretted hydrogen are 
mixed with 150 of oxygen, and exploded, the 
whole of both gases disappear y water and 
phosphoric acid are forced , when 100 mea- 
sures of the gas are mixed with 100 oxygen, 
and fired, the whole of both gases still disap- 
pears , in this case, water and phosphorous 
acid are formed , when 100 measures are 
mixed with less than 100 of oxygen, phos- 
phorous acid and water are formed, but part of 
the combustible gas remains unburnt 

As this gas is liable to be contaminated with 
hydrogen, sometimes largely, on account of 
the facility it possesses of depositing phos- 
phorus, it is expedient to ascertain the exact 
proportion of phosphuretted hydrogen to hy- 
drogen in any pioposed mixture Ihis I find 



PHOSPHUftETTED HYDROGEN 459 

may easily be done Whenever a sufficient 
quantity of oxygen is afforded, the whole of 
the combustible gas is consumed The exact 
volume of oxygen and its purity must be 
noted , the quantity of oxygen m the residue 
must also be noted Then the total dtmi* 
nution after the explosion, being diminished 
by the oxygen consumed, leaves the combus- 
tible gas Now, as phosphufetted hydrogen 
takes 14- times its bulk of oxygen, and hydro- 
gen takes t its bulk of oxygen , we shall ob- 
tain the following equations, if P denote the 
volume of phosphuretted hydrogen, H that of 
hydrogen, O that of oxygen, andS=P-f H, 
the whole of the combustible gas 

P= O IS 
H= ij S O 

From these equations, the ratio of the tw<y 
gases in any mixture is deduced The ana* 
lysis may be corroborated as follows To any 
mixture containing a certain volume of phos- 
phuretted hydrogen, let the same volume ot 
oxygen be added , after the explosion, the 
diminution will be just twice the volume of 
oxygen In tins case, the phosphuretted hy- 
drogen is preferred by the oxygen , phos- 
phorous acid and water are formed, and the 
hydrogen remains in the tube If more oxv- 



46O HYDROGEN WITH PHOSPHORUS. 

gea is put- than the phosphutetted hydrogen, 
then th$ diminution after firing is more thai* 
twice the oxygen 

The investigation respecting the proportion 
of hydrogen mixed with phosphuretted hy-- 
drogen, was instituted chiefly in consequence 
of a difference of opinion respecting the spe- 
cific gravity of the latter gas- I had found 
100 cubic inches to weigh about 26 grains , 
Mr* Davy informed me he had found 1OO 
inches to weigh only 10 grains the difference 
is enormous I requested Dr Henry would 
assist me in repeating the experiment We 
obtained a gas, such that 10O inches weighed 
14 grains , this result surprized me , but upon 
burning the gas with oxygen, it was found 
only to take its bulk of that gas, and conse- 
quently to be half hydrogen and half phos- 
phuretted hydrogen, which satisfactorily ex- 
plained the difficulty Mr Davy'b gas, I 
conceive, must have been f phosphuretted hy- 
drogen and y hydrogen, at the time it was 
weighed , however this may be, it is evident, 
from what ib related above, that nothing certain 
can he inferred relative to the specific gravity 
of thb gas, unless a portion of the gas be ana- 
lyzed previously to its being * v ^ 1 , a cir- 
cumstance of which I was not at first suffici- 
ently aware 



?HOSPHT7RETtEI> HYDROGEN. 461 

t have recently procured some phosphuretted 
hydrogen gas from caustic potash and phos- 
phorus , an accident prevented me obtaining 
a sufficient quantity to weigh , but I got 5 or 
6 cubic inches, which of course were mixed 
with the azotic gas previously put into the 
retort The pure combustible gas was of 
such character, that 100 measures required 
only 85 of oxvgen for their combustion , it 
was consequently 35 phosphuretted hydrogen 
and 65 hydrogen per cent and probably 
would have weighed aftei the rate of 10 or 
11 grains for 100 cubic inches I expected 
much purer gas 

As to the constitution of phosphuretted hy- 
drogen, it is clearly 1 atom of phosphorus 
united to 1 of hydrogen, occupying the same 
space as 1 of elastic hydrogen In combustion, 
the atom of hydrogen requires one of oxygen, 
and the atom ot phosphorus requires one or 
two of oxygen, according as \ve intend to 
produce phosphorous or phosphoric acid 
Hence it is that 100 measures of phosphu- 
retted hydrogen require 5O oxygen to burn the 
hydrogen, 50 more of oxygen to form phos- 
phorous acid, and 50 more to form phosphoric 
acid The weight ot the gas corroborate* this 
conclusion it ha*- been seen that the atou of 
phosphorus weighs nearly <> (page 415) , this 



462 CARBONS WITH SULPHUR, &C 

would make the specific gravity of phospbu- 
retted hydrogen equal to 10 times that of hy- 
drogen, which it actually is, or nearly so, from 
the foregoing experiments 



The next compounds to be considered m 
course, would be those of azote with cat bone, 
with sulphur, and with phosphorus , but such 
compounds either cannot be formed* or they 
ate yet unknown 

SLCTION iO 

CARBONE WITH SULPHUR, WITH 
PHOSPHORUS, AND SULPHUR WITH 
PHOSPHORUS 

1 Cai bone wfti Sulphur 

In the 42d vol of the An de Chimie, page 
J36, Clement and Desormes have announced 
a combination of carbone and sulphur, which 
they call cai burettcd sulphw They obtain it 
by sending the vapour of sulphur oxer red hot 
charcoal , it is collected in water in the form 
of an oily liquid of the specific gravity 1 3 
This liquid is volatile, like ether, expanding 
any gas into which it 1$ admitted, and forming 



CARBURETTED SULPHUR 468 

a permanent elastic fluid over the mercury of 
a barometer No gas is produced at the same 
time as the liquid When too much sulphur is 
driven through, instead of a liquid, a solid 
compound is formed which crystallizes in the 
tube They seem to have shewn that the 
compound does not contain sulphuretted hy- 
drogen. In the 64th vol of the Journal de 
Physique, A B Berthollet endeavours to prove 
that the liquid in question is a compound of 
hydrogen and sulphur, and contains no char- 
coal The facts adduced are not sufficient to 
decide the question either way I should be 
unwilling to admit, with Clement and De- 
sortnes, that the two inelastic elements, char- 
coal and sulphur, would form an elastic or vo- 
latile compound , yet, they have rendered it 
highly probable that charcoal makes a part of 
the compound, as it disappears during the 
process I think, it most probable, that Ber- 
thollet is correct in the idea that this liquid 
contains hydrogen We know of no other 
volatile liquid thai does not contain hydrogen 
Perhaps it will be found a triple compound of 
hydrogen, sulphur, and charcoal 



464 CARBONB WITH SULPHUR, &C 



2 Carbone with Phosphorus 

A combination of carbone and pftosphorus 
has been pointed out by Proust, in the 49th 
volume of the Journal de Physique, which he 
names phosplwret of carbone It is the reddish 
substance which remains when new made 
phosphorus is strained through leather in warm 
water The proportion of the two elements 
has not been ascertained. 



3 Sulphur with Phosphoi us 

Melted phosphorus dissolves and combines 
with sulphur, and that in various proportions, 
which have not jet been accurately ascer- 
tained The compounds may be denominated 
sulphurets of phosphoius The method of 
forming these compounds, is to melt a given 
weight of phosphorus in a tube nearly filled 
with water, and then to add small pieces of 
sulphur, keeping the tube in hot water, taking 
care not to exceed 160, or 170, or 180, be- 
cause the new compound begins to decompose 
water rapidly at those high temperatures 
Pelletier has given us some facts towards a 
theory of these various combinations, in the 



SULPHURETTED PHOSPHORTTS 465 

4th vol of the An de Chimie He found 
that a mixture of sulphur and phosphorus re* 
mamed fluid at a much lower temperature 
than either of them individually , and that 
different proportions gave different fusing or 
congealing points One part of phosphorus, 
combined with 4th of sulphur, congealed at 
77 , one part With ^, at 59, one part with 4, 
at 50 , one part with 1, at 4-1 , one part with 
2, at 544- , but a certain portion was fluid, 
and the rest solid , and one part with 3 4 at 
99 5 

One would be apt to think, from these ex- 
periments, that sulphur and phosphorus might 
be combined in all proportions , but the ob- 
servation on the 5th led me to suspect that it 
might have been applied to some others if the 
results had been carefully noted I mixed 18 J 
grains of phosphorus ind 13 of sulphur in a 
graduated tube, put in water, and immersed 
the whole into water of 160 The phos- 
phorus having been rendered fluid as usual, at 
100, graduall) reduced the sulphur, till the 
whole assumed a liquid form of the specific 
gravity 1 14 It remained uniformly fluid at 
45, but was wholly congealed at 42 Here 
were two atoms of phosphorus united to one of 
sulphur I then added 6 grains of sulphur, 
making the mixture 18t phosphorus, and 19f 



466 CARBOKE WITH SULPHUR, &C 

snlphur , this new mixture was reduced to uni- 
form fluidity at 170% and was of 1 47 specific 
gravity, reduced to 47, one part was fluid 
and the other solid, the latter being at the 
bottom of the tube This solid part was not 
completely reduced to fluidity in the tempe- 
rature 100* This seems to indicate that two 
distinct combinations took place , the one, 
two atoms of phosphorus and one of sulphur, 
liquid at 47 , the other, one atom ot phos- 
phorus and one of sulphur, solid under 100* 
I next added 6 grains more of sulphur, mak- 
ing in the whole 18| phosphorus and 26 sul- 
phur, consequently in such proportion as to 
afford a union of one atom of each , the union 
was completed in a temperature of 180 the 
specific gravity was 1 50 Cooled down to 
80% the whole was solid , heated to 1()0% the 
whole became a semi-liquid, uniform mass 
Being afterward^ heated to 140, the whole 
became fluH , but upon cooling again, the 
greatest part congealed at 1OO, but j-d or ^th 
remained liquid down to 47 From these 
experiments, it is most probable that one atom 
of each forms a combination which is solid at 
10O" or below , but that being heated, it is 
apt to run into the other mode of combination, 
or that constituted of two atoms of phosphorus 
and one of sulphur The properties of these 



POTASH 467 

two species of sulphuret of phosphorus I have 
not had an opportunity to investigate The 
water in the tube is evidently decomposed m 
part by the compound > it becomes milkv, 
probably through the oxide of sulphur, and 
both sulphuretted and phosphuretted hydrogen 
seem to be formed in small quantities at tem- 
peratures above 160 



SECTION 1 1 

FIXED ALKALIES 

The fate of the two fixed alkalies, potash 
and soda, has been rather remarkable They 
had long been suspected to be compound ele- 
ments, but no satisfactory proof was given 
At length Mr Davy, by his great skill and 
address in the application of galvanism to pro- 
duce chemical changes, seemed to ha\e estab- 
lished the compound nature of these elements, 
both by anilysis and synthesis I hey appeared 
to be metalliL ojiule\, or peculiar metals united 
to oxygen Consistent with this idea, some 
account of the metals, denominated putasturn 
and wdntin y has been given in this vvorL (See 
page 260) But from what follows, it ap- 
pears most probable, that these metals are 



468 FIXED ALKALIES 

compounds of potash and soda with hydrogen, 
and that the two fixed alkalies still remain 
among the undecompounded bodies 

1 Potash 

Potash is obtained from the ashes of burned 
wood Water dissolves the saline matter of 
the ashes, and may then be poured off and 
evaporated by artificial heat the salt called 
potash remains in the vessel If the salt so 
obtained be exposed to a red heat, it loses 
combustible matter, becomes white, and is in 
part purified m commerce it is then called 
pearl-ask This mass is still a mixture of va- 
rious salts, but is constituted chiefly of car- 
bonate of potash In order to obtain the pot- 
ash separate, let a quantity of pearl-asU (or 
what is still better, salt of tat tar of the shops, 
which is this pearl-ash reduced almost to pure 
carbonate of potash) be mixed with its weight 
of water, and the mixture be stirred , after 
the undibsolved salt has subsided, pour uff the 
clear solution into an iron pan, and mix with 
it a portion of hydrate of lime, half the weight 
of the liquid , then add a quantit) of water 
equal to the weight of the ingredient^, and 
boil the mixture for several hours, occasionally 
adding more water to supply the waste When 



POTASH 469 

the liquid is found not to effervesce with acids, 
the ebullition mav be discontinued After the 
lime has subsided, the clear liquid is to be de- 
canted, and then boiled down in a clean iron 
pan till it assumes a viscid form, and acquires 
almost a red heat It may then be poured 
into molds, &c and it immediately congeals 
The substance so obtained is potash nearly 
pure , but it still contains a considerable por- 
tion of water, some foreign salts, oxide of 
iron, and frequently some unexpelled carbonic 
acid The water may Amount to 20 or 25 per 
cent upon the whole weight, and the other 
substances to 5 or 10 per cent In this pro- 
cess, the carbonic acid of the potash is trans- 
ferred to the lime 

If potash of still greater purity be required, 
the method practised by BerthoHet may be pur- 
sued The solid potash obtained as above 
must be dissolved m alcohol , the foreign salts 
will fall to the bottom insoluble , the liquid 
solution may then be decanted into a silver 
bason, the alcohol be evaporated, and the fluid 
potash exposed to a red heat It may be 
poured out upon a clean polished surface, 
where it instantly congeals into solid plates of 
potash, which are to be broken and put into 
well stoppered bottles, to prevent the access of 
air and moisture I his potash is a solid, 



47O FIXED ALKALIES* 

brittle, white mass, consisting of about 84 
parts potash and 16 water, in 100 parts, and 
is the purest that has ever yet been obtained. 

Potash may be exhibited in a more regular 
crystalline form by admitting more water to 
it If the solution be reduced to the specific 
gravity of 1 6> or I 5, upon cooling, crystals, 
will be formed, containing about 53 per cent 
of water, or more, if the air is coldL These 
crystals are called hydrate of potash. Hence 
solid hydrate of potash may be formed, con- 
taining from 84 per cent of potash to 47 1 or 
under 

Potash has a very acrid taste * it is exceed- 
ingly corrosive if applied to the skin, so as to 
obtain the name of caustic The specific gra- 
vity of the common sticks of potash used by 
surgeons, I find to be 2 I , but these are a 
mixture or potash and carbonate of potash, 
with 20 or 30 per cent of water If pot-ash 
were obtained pure, I apprehend its specific 
gravity would be about 2 4 

When crystals of potash (that is the hy- 
drate) are exposed to heat, they become liquid, 
the water is gradually dissipated with a hissing 
noise, till at length the fluid acquires a red 
heat It then remains tranquil for some time , 
but if the heat be increased, white fumes be- 
gin to arise copiously The alkali and water 



POTASH 471 

both evaporate in this case, therefore, the pro- 
cess cannot be used to expel the last portion of 
water from the alkali If the hydrate be taken 
in the red hot and tranquil state, it contains 
84- per -cent potash and 16 water This is 
ascertained by saturating a given weight of it 
with sulphuric acid, when sulphate of potash 
is formed free from water, and 100 parts of 
the hydrate give only 84 parts to the new 
compound 

Water has a strong affinity for potash If a 
portion of the 84 per cent hydrate be put into 
as much water, great heat is immediately pro* 
duced, equal to that of boiling water But it 
is observable that the crystallized hydrate con- 
taining truch water, when mixed with snow, 
produces excessive cold When potash is ex- 
posed to the air, it attracts moisture and car- 
bonic acid, becoming a liquid carbonate Pat- 
ash dissolved in water, and kept in a stoppered 
bottle, retains its causticity it is called al- 
kaline ley, and may be had of various strengths 
and specific gravities 

Potash, and the other alkalies, change ve- 
getable colours, particularly blues, into green. 
Potash ib of great utility in the, arts and ma* 
nufactures, particularly in bleaching, dying, 
printing, soap and glass manufactures It 
unites with most acidb to form salts It does 



472 FIXED ALKALIES 

not unite with any of the simple substances, 
as far as is yet known, except hydrogen, and 
that in a circuitous way, as will presently be 
noticed The hydrate of potash unites with 
sulphur , but the compound, consisting of 
three or more principles, cannot yet be dis- 
cussed 

'I he theory of the nature and origin of pot- 
ash still remains in great obscurity The great 
question, whether it is a constituent principle 
of vegetables, or formed during their combus- 
tion, is not yet satisfactorily answered One 
circumstance is favourable to the investigation 
of the nature of potash, the weight of its ulti- 
mate particle is easily ascertained , it forms 
very definite compounds with most of the 
acidb, from which it appears to be 42 times 
the weight of hydrogen The following pro- 
portions of the most common salts with base 
of potash, are deduced from my experience 
they are such that good authorities may be 
found both for greater and less proportions of 
the different elements,, 

per cent. 

Carbonate of potash, 311, acul + OS IMSP, as 10 42 

Sulphate 44 7 (- 5j 1 H 42 

Nitrate 47 5 [- 52 *> i8 J-2 

MuJiate 31- \ h 60 b 'J2 42 



POTASH 473 

The above salts are capable of sustaining a 
red heat, and may therefore be supposed to 
be free from water , at all events, the potash 
must contain the same quantity of water m 
combination with the respective acids, as ap- 
pears from the uniformity of its weight The 
above numbers, 19, 34, 38 and 22 represent, 
as the reader will recollect, the weights of the 
atoms of the respective acids, except the nitric, 
which is double As water has so strong aa 
affinity for potash, and as the weight of the 
elementary particle of potash above deduced 
is more than five times that of water, it may 
still be supposed that water enters into the 
constitution of potash, or that it is compounded 
of some of the lighter earths with azote, oxy- 
gen, &c From present appearances, how- 
ever, the notion that potash is a simple sub- 
stance seems more probable than ever 

From the above observations, it appears that 
potash ought still to be considered as a simple 
substance, and would require to be placed 
among such substances, but that it cannot be 
obtained alone In that state which ap- 
proaches nearest to purity it is a hydrate, con- 
taining at least 1 atom of water united to 1 of 
potash, amounting to 16 per cent of water 
Ihib hydrate is therefore a ternary compound, 
or one of three elements, and ought to be post- 



47* FIXED ALKALIES 

poned till the next chapter but, in the pre- 
sent state of chemical science, utility must be 
allowed in some instances to supersede me- 
thodical arrangements The fixed alkalies are 
most useful chemical agents, and the sooner 
we become acquainted with them the better, 
more especially, as some of the first chemists 
of the present age have been led intc consi- 
derable mistakes, by presuming too much upon 
their knowledge of the nature and properties 
of these familiar articles 

In the Mentozres de FInsttlut de Fiance, 
1806, Berthollet published researches on the 
laws of affinity, from which some extracts are 
given in the Journal de Physique for March 
1807 By these, it appears that he found sul- 
phate of barytes to consist of 26 acid and 74 
base, and sulphate of potash of 33 acid and 67 
base The former of these results was corro- 
borated by the previous experience of The- 
nard , but both are so remote from the uniform 
results of other chemists, that they could never 
be generally adopted At length Berthollet 
discovered the error, and has announced it m 
the 2d vol of the Memoires d'Arcueii It 
consisted in mistaking the hydrates of barytes 
and potash for pure barytes and potash It 
seems to have been generally adopted, but 
certainly prematurely, that barytes and potash, 



HYDRATE OF POTASH 4T5 

in a state of fusion, were pure, or free from 
water But upon due investigation, he found 
that fused potash contains 14 per cent of wa- 
ter .. my experience as well as theory, leads 
me to adopt 16 per cent of water, which ac- 
cords with the position of 1 atom of each of 
the elements uniting to form the hydrate ; 
namely, 42 by weight of potash with 8 of 
water This discovery reconciles the jamng 
results on the proportions of the above neutral 
salts, and throws light upon some othsr inter- 
estmg subjects of chemical anal) sis* 



2 Hydi ate of Potash 

Upon turning my attention to this subject, 
I soon perceived the want of a table exhibit- 
ing the relative quantities of potash and water 
m all the combinations of these two element* 
In a state of solution, the specific gravity may 
be taken as a guide , but this is not quite so 
convenient when the compound is in a solid 
form I found nothing of the kind in any 
publication, and therefore undertook a course 
of experiments to determine the relative quan- 
tities of potash, &c in the various solutions 
The results are contained in the following 
table, which I would ha\e to be considered 



476 



FIXED ALKALIES 



only as an approximation to truth , but it wih 
certainly have its use till a more complete and 
accurate one be obtained Dr Henry was so 
obliging as to facilitate my progress, by pre- 
senting me with portions of the fixed alkalies, 
prepared after Berthollet's method. 

Table of the quantity of real potash in watery solution* 
of different specific giaviues, &c. 



Atoms. 


Potash 


Pota h ' 








Potash Water 


per cent 
by weight 


per cent, 
by measure 


Specific 
gravity 


CongeaDng 
point 


Boihny 
point 


1+0 


100 


240 


524 


unknown 


unknown 


j+ i 


4 


185 


22 


1000 


red heat 


1+2 


724 


145 


20 


500 Q 


600 


1+3 


635 


119 


1 88 


340 


420* 


1+ 4 


568 


101 


1 78 


220 


360 


1+ 5 


51 2 


86 


68 


150* 


320* 


1+6 


467 


75 


60 


100 


290 


1+7 


429 


65 


52 


70 


27 6* 


1+8 


396 


58 


47 


50 


265 


1+ 


368 


53 


44 


40 


255 


1+10 


344 


49 


42 




240* 




32 t 


45 


39 




240 




29 t 


40 


36 




234 




263 


35 


33 




220 




23 I 


30 


28 




22 1 




, 195 


25 


23 




220 




16 2 


20 


19 




218 




13 


15 


1> 




215 




9 5 


10 


11 




214 




47 


5 


00 




213 



Remarks on the Table 

The first column contains the number oi 
atoms of potash and water in the several com 



HYDRATE OF POTASH 477 

binations to 10 atoms of water the weight of 
an atom of potash is taken to be 42, and 1 of 
water 8 From these data the second column 
is calculated There did not appear any strik- 
ing characteristic of distinction between the 
first, second, third, &c. hydrates* (if they may 
be so called) except that the first bears a red 
heat in the liquid form, With tranquillity and 
without loss of weight Before this, the wa- 
ter is gradually dissipated \vith a hissing noise 
and fumes I remarked, however, that when 
a solution of potash is boiled down till the 
thermometer indicates upwards of 300, the 
evaporation of the water, and the rise of the 
thermometer* are desultory , that is, the ope- 
rations appear somewhat stationarv for a time, 
and then advance quickly , how far this may 
arise from the nature of the compound, or 
from the mperfect conducting power of the 
liquid in those high temperatures, I could not 
determine without more frequent repetitions 
of the experiment 

The third column u>, as usual, obtained by 
multiplying the second column by the specific 
gravity y it is often more convenient in prac- 
tice to estimate quantity by measure than by 
weight 

The fourth column denotes the specific gra 
vity , below 1 50 the hydrate is complete!) 



ALKALIES. 

fluid, of may be made so by a moderate heat , 
but above that temperature, I tound some dif- 
ficulty in ascertaining the specific gravity, and 
was obliged sometimes to infer it from the 
tenor of the table The common sticks of 
potash of the druggists are of the sp gr 2 1, 
which I found by plunging them into a gra- 
duated tube filled with mercury^ and marking 
the quantity that overflowed These sticks 
are a mixture of hydrate and carbonate* Real 
potash must, I conceive, be heavier than they 
are The relation of the second and fourth 
columns was ascertained by taking a given 
weight of the alkaline solution, saturating it 
with test sulphuric acid (1 134), and allowing 
21 grains of alkali for every 10O measures of 
acid (containing 17 real} which the alkali re- 
quired 

The 5th column denotes the temperatures at 
which the different hvdrates congeal or crys- 
tallize This part of the subject deserves much 
more accurate enquiry than I have been able 
to bestow upon it No doubt the different 
hydrates might be distinguished this way 
Proust talks of a crvstallized hydrate of potash, 
containing 30 per cent of water , and Lowitz 
of one containing 43 per cent, of water They 
calculate, I presume, upon the supposition of 
fused potash being free from water , if so, 



CARBONATE OF POTASH 479 

Proust* s hydrate is the fourth of our table, and 
Lowitz's the sixth I would not have much 
trust to be put m the temperatures I have 
marked in this column 

The sixth column indicates the temperatures 
at which the different specific gravities boil 
This is easilj ascertained, except tor the high 
-degrees, in which an analysis of the hydrate 
was required upon every experiment I believe 
the results will be found tolerably accurate 
As the range of temperature is large, this may 
be found a very convenient method of ascer- 
taining the strength of alkaline solutions, when 
the specific gravities are unknown 

3 Carbonate of Potash 

Though it be premature to enter into the 
nature of carbonate of potash, a triple com- 
pound, yet its utility as a test is such as to 
require it to be noticed in the present section 
Indeed it may generally be a substitute for the 
hydrate of potash, and it can much more rea- 
dily be procured in a state of comparative 
purity The carbonate I mean is that which 
consists of one atom of acid united to one of 
potash, which by some writers is called a wh- 
ew bouate It is, of couise, constituted of J9 



480 FIXED ALKALIES, 

parts of acid by weight united to 42 of potash 
This salt is to be had in tolerable purity of the 
druggists, under the name of salt of tartar 9 
but when it is to be used in solution for pure 
carbonate, a large quantity of the salt, and a 
small quantity of water, are to be mixed and 
agitated , then let the undissolved salt subside, 
and pour off the clear solution, which may be 
diluted with water, &c 

This salt is well known to be, like the dry 
h}drate of potash,, very deliquescent I took 
43 grams of carbonate of potash that had just 
before been made red hot, put them into a 
glass capsule exposed to the air, in one day 
the weight became 60 grains , in three days, 
61 grains, in seven days, 75 grains, in H 
days, 89 grains, in 21 days, 89+ grains, in 
25 days, 90 grains The specific gravity was 
151- nearlv All the water is, however, driven 
oft by a moderate heat , namely, that of 280. 
It supports a high red heat before fusion, and 
when fused loses no weighs remaining with- 
out sublimation, and undecompounded I 
ascertained that it was a perfect carbonate, by 
dissolving 61 grains of pure dry salt in lime 
water, when 1-2 grains of carbonate of lime 
were thrown down, corresponding to 19 grains 
of carbonic acid 



CARBONATE OF POTASH 



481 



Table of the quantity of real carbonate of potash m watery 
solutions of different specific gravities, 



Atoms. 


Garb Potash 


Garb Potash 






Ctrb 


per cent 
by weight 


per cent 
by measure 


Specific 
gravity 


8oUu| 
poiat. 


of Pot Water 










1+ 


100 


260 


260 


28Q* 


3+ 1 


884 


212 


240 


265 


1+ 2 


792 


170 


215 


258 


1+ 3 


71 8 


140 


1 95 


252 


1+ 4 


656 


118 


1 80 


247 


1+ 5 


604 


103 


170 


244* 


1+6 


56 


91 


1 63 


241 * 


1 + 7 


52 1 


82 


158 


238 


1+ 8 


48 8 


75 


1 54 


235* 


1+ 9 


45 8 


69 


150 


232* 


1 + 10 


43 3 


6* 


146 


229 




41 7 


60 


1 44 


227 




39 


55 


1 H 


225 




362 


50 


1 38 


222* 




33 


45 


1 3i 


220 




305 


40 


1 31 


218* 




27 3 


35 


1 28 


217* 




24- 


30 


1 2a 


216* 




20 5 


25 


1 22 


215* 




16 8 


20 


1 19 


214* 




132 


15 


1 15 


214* 




y 


10 


1 11 


213 




47 


5 


1 06 


213 



This table is similar in structure to the pre- 
ceding The first column contains the number 
of atoms of w ater joined to one of carbonate of 
potash, which last weighs 61 The second 
contains the weight of carbonate of potash per 
cent in the compound, and the third the 
grains of carbonate in 100 water gram mea- 
sures of the compound, found by multiplying 



482 FIXSD ALKALIES 

the numbers m the second and fourth columns 
together The fourth contains the specific 
gravities , the relations of these to the quan- 
tities in the second column were found, by 
taking a given weight of the solution, arid sa- 
turating it with a certain number of measures 
of test sulphuric acid (1 134), allowing 21 real 
potash, or 30^ carbonate, for every 100 mea- 
sures of acid required , because such acid con- 
tains 17 per cent by measure of real sulphuric 
acid, and that requires 21 of potash 

I he strongest solution of this salt that can be 
obtained is of the specific gravity 1 54 This 
consists of 1 atom of carbonate and 8 of water, 
but by putting dry carbonate into that solution, 
various mixtures may be formed up to the spe- 
cific gravity 1 80 , above that the specific gra- 
vity is scarcely to be obtained but by inference 
I could not obtain a solid stick of fused car- 
bonate but what was spongy, I suppose from 
incipient decomposition It may be observed, 
that the specific gravity 1 25, which contains 
SO per cent of carbonate, is that which I 
prefer as a test for acids , because the solution 
contains 21 per cent pure potash, and 100 
measures of it consequently require 100 mea- 
sures of the test acids 

I found a specimen of the pearl ash of com- 
merce to contain 54 parts carbonate of potash, 



CARfcONATE OF POTASH , 483 

22 parts of other salts, and 24- parts of water 
in the hundred 

The fifth column denotes the temperature 
at which the saline solutions boil This will 
be found generally a good approximation to 
truth. I observed the thermometer did not 
rise above 280 as long as any visible moisture 
remained , as soon as that vanished, the salt 
assumed the character of a hard and perfectly 
dry substance 

In the course of these experiments, I took 
a quantity of carbonate of potash, and heated 
it red hot , then weighed it , after which I 
put to it as much water as afforded 1 atom to 
1 , namely, 8 parts water to 61 salt The 
salt was then pulverized in a mortar , it was 
put out upon white paper, and appeared a 
white, dry bait , but upon pouring it back 
into the mortar, some particles of the salt ad- 
hered to the paper The same quantity of 
water was again put to it Upon mixing 
them with a knife, the whole mass assumed a 
past) consistence, and adhered to the knife in 
the shape of a ball , after being well rubbed 
in the mortar, it again assumed a white, dry 
appearance Upon paper, it seemed like salt 
of tartar some time exposed to the air Several 
particles stuck to the paper, but were easily 
removed by a knife Ihe addition of another 



484 fIXED ALKALIES 

atom of water reduced the compound to the 
consistence of bird-lime , but after standing 
rt cat like half dried clay The next atom of 
water reduced it to the consistence of book- 
binders paste The fifth atom of water re- 
duced it to a thick fluid, consisting of dis- 
solved and undtssolved salt This, by the suc- 
cessive application of like portions of water, 
became a perfect fluid with 8 atoms of water 
to 1 of carbonate of potash. Its specific gra- 
vity was IS, but there was some undissolved 
sulphate of potash subsided, the salt of tartar 
not having been previously purified- 



4 Potasium, or Hydruret of Potash 

Since writing the articles on Potasmm and 
Sodium (page 260 and seq ), and the subse- 
quent articles on fluoric and muriatic acid 
(page 277 and seq ), a good deal more light 
has been thrown on these subjects Two pa- 
pers on the subjects have been published by 
Mr Davy , a series of essays by Gay Lussac 
and Thenard, are contained in the 2d vol of 
the Memoires d'Arcueil , the same volume 
also contains a paper by Berthollet, announc- 
ing an important discovery relating to the fixed 
alkalies , namely, that in a state of fusion by 



POTASIUM, OR KYDRURET QT POTASH 485 

heat, they contain a definite proportion of 
water in chemical combination Upon re- 
considering the former facts, and comparing 
them with the more recent ones, I am obliged 
to adopt new views respecting the nature of 
these new metals Mr Davy still adheres to 
his original views, and which indeed were the 
only rational ones that could be formed (sup- 
posing the fused alkalies to contain no water), 
namely, that potash is the oxide of potasmm t 
Gay Lussac and Thenard, on the contrary, 
consider potash as undecompounded, and po- 
tasium a compound of hydrogen and potash, 
analogous to the other kno<vn compounds of 
hydrogen and elementary principles This 
last is the only one, I think, that can be ad- 
mitted either from synthetic or analytic expe- 
riments, so as to be reconcileable with the 
facts , but I do not coincide with all the con- 
clusions which ihe Trench chemists have de- 
duced Mr Davy has furnished us with the 
most definite and precise facts , and though I 
was led to controvert some of them (bee page 
289 and seq ), it was principally through my 
having adopted his views ot the nature of po- 
tasium I am now persuaded those results were 
more accurate than I imagined 

Mr Davy first attempted ro decompose the 
fixed alkalies, by applying Voltaic electricity 



486 POTASH WITH HYDROGEN 

to saturated watery solutions , in this case, 
oxygen and hydrogen gas were obtained, evi- 
dently proceeding, as he concluded, from the 
decomposition of the water But when any 
potash that had previously been fused, was 
substituted for the watery solution, no hydro- 
gen gas was given out at the negative pole, 
but potasmm was formed, and pure oxygen 
was given out at the positive pole The re- 
sidual potash was unaltered The conclusion 
he drew was, that the potash was decomposed 
into potasmm and oxygen But it now ap- 
pears, that fused potash is composed of 1 atom 
of water and 1 of potash r lhe electricity 
operates upon this last atom of water to se- 
parate its elements , it succeeds in detaching 
the atom of oxygen, but that of hydrogen 
draws the atom of potash along with it, form- 
ing an atom of potasmm The atom of hy- 
drate weighing 50 (= 42 potash + 8 water) is 
decomposed into one of potasmm, weighing 
43, and one of o\vgcn weighing 7 Hence 
the atom of potasmm is composed of 1 pot- 
ash + 1 hydiogui, weighing 4S , and not ot 
1 potash 1 oxygen, weighing U, as stated 
at page 262 

The method of obtaining potasmm, disco- 
vered by the French chemists, is to hnd the 
first hydiate of potash in a state of vapour over 



POTASIUM, OR mDRXTRET OF POTASH 487 

red hot iron turnings, in an iron tube intensely 
heated , hydrogen gas is given out, potasmm 
is formed and condensed in a cool part of the 
tube, and part of the potash is found united 
to the iron In this mode of producing pota- 
smm, its constitution is not so obvious as m 
the former The two methods, however, to- 
gether, shew that fused potash contains both 
oxygen and hydrogen, which is now abun- 
dantly confirmed by experiments of a different 
kind It seems probable that in the latter 
method the hydrate of potash is partly decom- 
posed into potash and water, and partly into 
potasjum and oxygen , in both cases the iron 
acquires the oxygen 

The specific gravity of potasmm is 6, or 
796, according to Davy , but 874 according 
to Gav Lussac and Fhenard The levity ot it, 
combined with its volatility at a low red heat, 
agrees with the notion of its bein^ potash and 
Hydrogen, or potaswtted hudnwtn, resembling 
the other Lnown compounds of sulphur, phos- 
phorus, charcoal, arsenic, &c combined with 
hydrogen 

When burned in oxygen gas, potasmm pro- 
duces potash as dry as possible to be procured, 
according to Mr Daw, that is, the first hy- 
diate When potasmm is thrown into water 
it burns rapidlv, decomposing the water, and 



488 POTASH WITH HYDROCEK 

giving off hydrogen Calculating the oxygen 
from the quantity of hydrogen, Mr Davy find*, 
100 (hydrate of) potash contain from 13 to 17 
oxygen Gay Lussac seems to make it H 
For, 2 284 grammes of potasmm gave 649 
cubic centimetres of hydrogen , reduced, 35 5 
grains gave 34 5 cubic inches English measure, 
which correspond to 17 25 inches of oxygen 
= 59 grains Hence 35 3 + 5 9 = 41 2 
grains of hydrate , and 412 59 100 I4 f 
But this is exactly the quantity that theory 
would assign , for, 43 potasmm + 7 oxygen 
= 50 hydrate, which gives just 14 oxygen in 
the hundred 

Potabium burns spontaneously in oxymunatic 
acid gas, muriate of potash is formed, and 
probably water It decomposes sulphuretted, 
phosphuretted, and arsenmrettecl hydrogen gas, 
rT^- 4 ^ to Gay Lusbac and Thenard, and 
unites to the sulphur, &c with some of the 
hydrogen Mr Davy finch tellurium to unite 
with the hydrate of potash by Voltafc electn 
city without decomposing it Potasmm burns 
in nitrous gas and nitrous oxide, forming dry 
hydrate of potash, and evolving a/ote It 
burns in sulphurous and carbonic acid, and in 
carbonic oxide , hydrate of potash which unites 
to the sulphur is formed, or hydrate of potash 
and charcoal 



*QTASIITM, OR. 3YDRURET OF POTASH 489 

The combustion of potaswra in muriatic acid 
gas is particularly worthy of notice Both Mr 
Davy and the French chemists agree that when 
potaswra is burned in muriatic acid gas, mu- 
riate of potash is formed, and hydrogen evolved, 
tvhich agrees in quantity with that evolved in 
the decomposition of water by the same quan- 
tity of metal But, what is most astonishing, 
they both adopt the same explanation, when 
their different views of the constitution of po- 
tasmm require them to be opposite Mr 
Davy had two ways in which he might ac- 
count for the phenomenon , the one was to 
suppose that a patt of the acid was decom- 
posed, and furnished the oxygen to the metal 
to form the oxide (potash), which joined to 
the remainder of the aac!, and the hydrogen 
was an evolved elementary principle of that 
part ot the acid decomposed , and the other, 
to suppose that the acid gas contained in a 
state of union just as much water as was suffi 
cient to oxidate the metal (this would have 
been thought an extraordmaiy circumstance 
a few years ago) Either of these positions 
was consistent , but he adopted the latter, 
and seemed to confirm it b) shewing that a 
ijiven quantity of muriatic acid gas afforded 
the same quantity of muriate of silver, whether 
combined previously with potash or potasium 



490 POTASH WITH HYDROGEN 

This explanation did not meet my views as 
well as the former I endeavoured to account 
for the facts (page 289) on the notion of a de- 
composition of the acid Two circumstances 
conspired to incline me to this view The one 
was, that hydrogen seemed on other accounts 
to be a constituent of muriatic aci^l , the other 
was, that water does not appear in any other 
instance to be combined with any elastic fluid , 
I mean in such way that if the water be re- 
moved, the rest of the molecule will carry 
along with it the character of the whole In 
one respect I mistook the data, having over- 
rated the weight of muriatic acid gas I 
would now be understood to abandon the ex- 
planation founded on the decomposition of the 
acid , and to adopt the much more simple one 
that the muriatic acid combines with the pot- 
ash of the potasium, at the same instant ex^ 
pelhng the hvdrogen , in this, way there is no 
occasion for any water either combined or 
otherwise It exceeds my comprehension how 
Gay Lussac and Ihenard should insist so 
largely on the opinion that muriatic acid gas 
contains water, and that principally, as it 
should seem, in order to account for the hy- 
drogen evolved during the combustion of po- 
tasium, and the supposed oxvdation ot the 
metal 



POT ASIUM, OR. HYDRURET OF POTASH 49 1 

It has been stated that potasmm burns in 
silicated fluoric acid gas (page 283), the result 
is fluate of potash and some hydrogen. The 
theory of this is not obvious 

Potasmm acts upon ammomacal gas Mr 
Davy found that when 8 grains of the metal 
were fused in ammomacal gas, between 12f 
and 16 cubic inches of the gas were absorbed, 
and hydrogen evolved corresponding to the 
oxydation of the metal by water, that is, 1 
atom of hydrogen for 1 atom of potasmm. 
The new compound becomes of a dark olive 
colour By applying a greater degree of heat 
the ammonia is in part expelled again , but 
part is also decomposed Gay Lussac and 
Thenard say, that by admitting a few drops 
of water to the compound, the whole of the 
elements of the ammonia are recoverable, and 
nothing but caustic potash remains Mr 
Davy affirms the results of the decomposition 
to be somewhai different It seems pretty 
evident, that in this process two atoms of am- 
monia unite to one ot potasium, expelling its 
hydrogen it the sunc moment For, 43 grains 
of potasmm would require 12 of ammonia , and 
therefore 8 will require 2J giains, which cor- 
respond to 12] cubic inclus 



492 FIXED ALKALIES 



5 Soda 

Soda is commonly obtained from the ashes 
of plants growing en the sea-shore, particularly 
from a genus called salsola , in Spam, where 
this article is largely prepared, it is called ba- 
rilla In Britain, the various species offucus 
or sea- weed are burnt, and their ashea form a 
mixture containing some carbonate of soda ^ 
this mixture is called kelp- Soda is found m 
some parts of the earth combined with car- 
bonic acid, and in others combined with mu- 
riatic aud, as minerals, and hence it has been 
called the fowl or mineral alkali, to distin- 
guish it from potash or the vegetable alkali 

To obtain soda in as pure a state as possible, 
recourse must be had to a process similar to 
that for oV.Mi i.ig potash Ptne carbonate of 
soda must be treated with hydrate of lime and 
water , the carbonate of soda is decomposed , 
the soda remains in solution in the liquid, the 
carbonic acid unites to the lime and the uex\ 
compound is pieupitated Mterwards the 
clear liquid must be decanted and boiled 
down , the water gradually goes off with a 
hissing noise till the soda acquires a low red 
heat, when the alkali and remaining water 
become a tranquil liquid This liquid miy be 



SODA 403 

run out into mold*, &c when it instantly con- 
geals into a hard mass, and is then to be pre- 
served in bottles for use If still greater heat 
be applied, the alkali and water are together 
dissipated in white fumes 

Soda thus obtained is a solid, brittle, white 
mass, consisting of about 78 parts pure soda 
and 22 water per cent , according to d'Arcet 
(Annales de Chimie, Tome 68, p 182) the 
alkali is only 72 , but I believe that is too low 
With more water, soda may be had in crystals, 
like potash, probably containing 50 or 6O per 
cent of water Soda, like potash, is extremely 
caustic , it is deliquescent, and produces heat 
when dissolved in water The specific gra- 
vity of fused soda I find to be 2, by pouring it 
into a graduated glass tube There is some 
reason to apprehend that pure soda, could it 
be obtained, \vould be specifically heavier than 
potash, though its ultimate particle is certainly 
of less weight than that of the htter The 
properties and uses of soda are much the same 
as those of potash , indeed, the two alkalies 
were long confounded, on account ot then re- 
semblance I he compound* into winch they 
entei are in many instances essentially di'lercnt, 
and the weights of their atoms are \ery un- 
equal Ihe origin ot soda in \LgaibYs is 
somewhat obscure, though it may be derived 



494 HXED ALKALIES 

from the* muriate of soda in the water of 
the sea 

The weight of an atom of soda is easily de- 
rived from the many definite compounds which 
it forms with the acids , it appears to be 28 
times that of hydrogen The carbonate, sul- 
phate, nitrate and muriate of soda, are all well 
known salts From a comparison of my own 
experiments with those of others on the pro- 
portions of these salts, free from water, 1 de- 
duce the following 

per cent 

Carbonate of soda 4-0 1 acid, + 50 6 base, as 19 28 

Sulphate 54 8 45 2 34 28 

N,trate 57 6 42 4 33 25 

Munate 44 56 22 28 

These proportions scarcely differ 1 per cent 
from those of Kirwan and other good autho- 
rities The numbers 19, 34, 3S and 22 being 
the weights of the respective atoms of acids, 
the number 28 must be the weight of an ertorn 
of soda Hence we find that soda is a peculiar 
element, diffeung from every one we have yet 
determined in \\eight From the weight of 
the element soda, it may be suspected to be a 
compound of water, oxygen, or some of the 
lighter elements , but from present appear- 
ances, no such suspicion seems well founded 
Soda should then with propnctv, be treated 



HYDRATE OF SODA, 495 

as an elementary principle We shall proceed 
to the hydrate, the carbonate, and the hy- 
druret of soda, for reasons which have been 
given under the head of potash 



6 Hydrate of Soda 

Soda, m what has till lately been considered 
its pure state, is combined with water The 
smallest portion of water seems to be one atom 
to one of soda , that is, 8 parts of water by 
weight to 28 of soda, or 22 per cent of wa- 
ter I have not obtained soda purer than that 
of d'Arcet of 72 per cent , but it always con- 
tained some carbonic acid and other impu- 
rities, which incline me to conclude that 78 
per cent would be the highest attainable pu- 
rity , this may be called the first hydrate it is 
hard and brittle, and twice the weight of wa- 
ter. The second, third, fourth, and fifth hy- 
drates are, I apprehend, crystalline , but n^y 
experience does not warrant me to decide upon 
their nature , the sixth, and those With more 
water, are all liquid at the ordinary tempera- 
ture , their specific gravity is obtained in the 
usual way, and the corresponding quantity of 
real alkali is ascertained by the test acids 

'I he following Table foi soda, is constructed 
after the mannei of that for potash (page 



496 



ALKALIES 



It will be found moderately accurate , but I 
could not give it the attention it deserves 
Nothing of the kind has been published to my 
knowledge 9 yet, such tables appear to me so 
necessary to the practice of chemical enquiries, 
that I have wondered how the science could 
be so long cultivated without them 

That solution which will be found most 
convenient for a test, is of the specific gravity 
1 16 or 1 17, and contains 14 per cent by 
measure of real alkali , consequently, 100 mea- 
sures require the same volume of acid tests for 
their saturation 

Table of the quantity of real soda in watery solutions ot 
different specific gravities, &c 



A-toms. 


Soda 


Soda 








Soda Abater 


per cent 
by weight 


per cent 
by measure 


Specific 
gravity 


Congealing 
point 


Boiling 
point 


1 + 


100 


230 5 


230? 


unknown 


unknown 


1 + 1 


77 M 


150 


200 


1000 


red hot 


1 + 2 


636 


118 


1 85 


5000 


600 


1 + 3 


53 8 


93 


1 72 


250 


400* 


1 4- 4 


4-60 


76 


1 03 


150 


300 


1 + 5 


4-1 2 


64- 


1 56 


80 


280 


1 +. 6 


368 


55 


50 




205 




34- 


50 


47 




255 




31 


1-5 


4V 




2J-8 4 * 




29 


4-0 


40 




242 




26 


35 


1t> 




2J5* 




23 


30 


32 




25?S 




19 


25 


2<> 




224* 




16 


20 


23 




220 C 




13 


15 


18 




217 




P 


10 


12 




214 




47 


5 


06 




213* 



CAKBONATE OF SODA 49? 



7 Carbonate of Soda 

The salt I call carbonate of soda^ is to be 
bad of the druggists in great purity, under the 
name of purified sub-carbonate of soda It is 
obtained in the form of large crystals, contain- 
ing much water , but when exposed to the air 
for some time, these crystals lose most of their 
water, aaid become like flour I took 100 
grains of fresh crystallized carbonate of soda, 
and exposed it to the action of the air in a 
saucer In 1 day it was reduced to 80 grains , 
in 2 days, to 64 grains , in 4 days, to 49 grains , 
in 6 days, to 45 grains , in 8 days, to 44 grains , 
and in 9 days it was still 44 grams, had the 
appearance of fine dry flour, and probably 
would have lost no more weight It was then 
exposed to a red heat, after which it weighed 
37 grains nearly Now, it is a well established 
fact, that the common carbonate of soda, heated 
red, is constituted of 19 parts ot acid and 28 
of soda , or 40 4 acid and 59 6 base, per cent 
nearly Klaproth says, 42 acid, 58 base , 
Kirwan says, 401 acid, 599 base It is 
equally well established that the crystallized 
carbonate recently formed in a low tempe- 
rature, contains about 63 per cent \\ater, as 
above determined All experience confirms 



498 FIXED ALKALIES 

this, Befgman and Kirwan find 64 parts of 
water, Klaproth 62, and d'Arcet 63 6 Hence 
the constitution of the crystallized carbonate 
is easily ascertained , for, if 37 63 47 
(= 19 + 28) 80, the weight of water attached 
to each atom of the carbonate , that is, 10 
atoms of water unite to 1 of carbonate of soda 
to form the common crystals Again, if 47 
8 37 6 3 = the weight of water attached 
to 37 parts of carbonate of soda, to correspond 
with 1 atom of water , but 37 + 6 3 = 43 3 , 
from this it appears that 100 parts of crystal- 
lized carbonate being reduced to 44 or 43 3, 
indicates that all the 10 atoms of water are 
evaporated, except one It should beem, then, 
that the ordinary efflorescence of this salt is not 
dry carbonate, but 1 atom of caibonate and 1 
of water This supposition is confirmed by ex- 
perience , for, m 5 days the above 37 grams of 
heated carbonate became 44 grains by ex- 
posure to the air 

There is another very remarkable character 
of the carbonate of soda, which, however, I 
apprehend will be found to arise from a ge- 
neral law m chemistry , when a quantity of 
common crystallized carbonate is exposed to 
heat in a glass retort, as soon as it attains a 
temperature about 150, it becomes fluid as 
water, but when this fluid is heated to 212, 



CARBONATE OF SODA 499 

and kept boiling a while, a hard, small grained, 
salt is precipitated from the liquid, which, 
upon examination, I find to be the ffth h>- 
drate, or one atom of carbonate of soda united 
to 5 atoms of water For, 100 grains of this 
salt lose 46 by a red heat , but 1 atom of car- 
bmiate weighs 47, and 5 atoms of water weigh 
4O, together making 87, now, if 87 ot such 
salt contain 4O water, 100 will contain 46 
The clear liquid resting upon the fifth hydrate 
has the specific gravity 135, on cooling, the 
whole liquid crystallizes into a fragile, icy mass, 
which dissolves with a very moderate heat 
This appears by the test acid to be constituted 
of 1 atom of carbonate and 15 atoms of water* 
Thus the tenth hydrate, by heat, is resolved 
and converted into the fifth and fifteenth , in 
like manner, probably, the fifteenth might be 
transformed into the tenth and thirtieth hy- 
drate When anv solution below 1 35 sp 
gravity is set aside to csystajlize, the fi r teenth 
hydrate is formed in the liquid, and finally the 
residuary liquid is reduced to the sp gravity of 
1 18 By treating this liquid solution with 
the tebt acids, it will be found to consist of I 
atom of cirbonate to 30 of water It is of 
course that solution \\hich the common crys- 
tals of carbonate aluajs form, \\htn duly agi- 
tated with water or a satiuuted solution at 



500 FIXED ALKALIES 

the mean ordinary temperature of the atmo- 
sphere By heat, other liquid solutions may 
be obtained from 1 85 to 1 35 , but they soon 
crystallize , such may be called supersaturated 
solutions 

The different species of hydrates in crystals 
have different specific gravities, as might be 
expected , that of the fifteenth is 1 35 , that 
of the tenth is I 42, and that of the fifth 1 64 
These were found by dropping the crystals 
into solutions of carbonate of potash till they 
were suspended, or by weighing them in sa- 
turated solutions of the same I could not 
ascertain that of the pure carbonate and the 
first hydrate 

When carbonate of soda is used for a test 
alkaii, the specific gravity 1 22 would be that 
solution which contains 14 per cent by mea- 
sure of alkali, of which 100 measures would 
require 100 of test acid for saturation , but, as 
that solution cannot be preserved without par- 
tial crystallization, it will be better to substitute 
a solution of half the strength , namely, that of 
111, then 200 measures of the solution will 
require 100 of test acid 

The follow mg Table contains the characters 
of various combinations of carbonate of soda 
and water, resulting from my investigations 



CARBONATE OP SODA 



501 



Table of the quantity of real carbonate of soda m watery 
compounds of different specific grauue& 



Atoms 


Garb Spda 


Garb c oda 








Garb 


per cent 
by weight 


per cent 
by measure 


Specific 
gravity 


Congealing 
point 


Boiling 

point. 


Soda. Water 












1 + 


100 


200 > 


200? 


unknown 


unknown* 


1 - 


- I 


85 5 


162? 


190? 


i 


. 


1 - 


- 5 


54 


89 


161 


. 


. . . 


1 - 


-10 


37 


525 


1 42 


150 




i ^ 


-15 


288 


39 


I 35 


80 


220 


1 +20 


227 


28 


1 26 




217 


1 +30 


164 


195 


1 18 




214 






15 


1 15 




_ 






10 


1 10 




213* 






5 


105 




_ 



The state of the carbonates m the above 
table it may be proper to notice The pure 
carbonate is in the state of a dry powder , so 
is the first hydrate, not to be distinguished in 
appearance from the pure carbonate The 
fifth hydrate may be obtained in a crystalline 
mass, by heating the common carbonate till 
a proper portion of water is driven off Its 
specific gravity is then easily found The 
tenth hydrate is the common carbonate of the 
shops m crystals The fifteenth hydrate may 
be had either in a liquid or solid form, as has 
been observed The twentieth hydrate is a 
liquid vuthout my remarkable distinction that 
I have discovered It is liable to partial crys 
talhzation I he thirtieth hvdrate is a liquid, 
being the satuiatcd solution at common tern- 



502 FIXED ALKALIES 

perature , this would probably wholly crys- 
tallize at no very reduced temperature The 
2d, 3d, 4th, 6th, &c hydrates, I have not 
found to offer any remarkable discrimination 



8 Sodium> or Hydrwet of Soda 

According to the present st&te of our know- 
ledge, the account of sodium given at page 
262, will require some modification As the 
article from which sodium has always been 
obtained is the first hydrate of soda, and as m 
the electrization of fused hydrate of soda, no 
gas is given out, according to Mr Davy, but 
oxygen , it follows of course that sodium must 
be a compound of soda and hydrogen, which 
may be called a hydruret of soda Mr Davy, 
conceiving soda in a state of fusion to be pure 
or free from water, as was the common opinion 
at the time, concluded that in the electrization 
of it the soda was decomposed into sodium 
and oxygen This conclusion does not now 
appear to be tenable, though Mr Davy still 
adheres to it, without having shewn what be- 
comes of the water acknowledged to be pre- 
sent in every instance of the formation of so* 
dium and potasium (Philos Trans 1809), to 



SODIUM 508 

the amount of 16 per cent upon the com- 
pound 

Though Mr Davy's original method of ob- 
taining sodium by Voltaic electricity is the 
most instructive, as to the nature of the new 
prpduct, yet, that of Gay Lussac and 1 henard 
is the most convenient when a quantity of the 
article is required, That is, to pass the vapour 
of red hot hydrate of soda over iron turnings 
in a gun barrel, heated to whiteness The 
hydrate seems to be decomposed in two ways , 
in part it is resolved into sodium, or hydruret 
of soda, and oxygen, the former of which dis- 
tils into a cooler receptacle of the barrel, and 
the latter unites to the iron , in part, the hy- 
drate is decomposed into water and soda, and 
the former again into oxygen, which unites to 
the iron, and hydrogen which escapes, whilst 
the soda unites to the iron or its oxide, forming 
a white metallic compound 

The specific gravity of sodium is stated by 
Mr Davy at 9348 The weight of its ulti- 
mate particle (being 1 atom of soda and 1 of 
hydrogen) must be 29, and not 21, as stated 
at page 263 Consequently, 100 parts of the 
first hydrate of soda, or fused soda, contain 
80 6 sodium and 19 4 oxygen per cent This 
agrees with that one of Mr Davy's experi- 
ments which gave the least portion of oxygen 



504 EARTHS 

Sodium amalgamates with potasium, ac- 
cording to Gay Lussac and Thenard, in va- 
rious proportions, and the alloys are more 
fusible than either of the simple metals, being 
in some cases liquid at the freezing point of 
water In general, the properties of sodium 
are found to agree with those of potasmm so 
pearly, as not to require distinct specification. 



SECTION 12 

EARTHS 

The class of bodies called earths by chemists 
are nine in number, their names are Lzme, 
Magnesia, Barytes, Shontitcs, Alumine or 
Argil> Siler, Yttna, Glucine and Zircone 
The three last are recently discovered and 
scarce 

The earths constitute the bases of the fossil 
kingdom Though they have frequently been 
suspected to be compound bodies, and several 
attempts have been made to decompose them, 
it does not yet appear but that they are simple 
or elementary substances Some of the earths 
possess alkaline properties, others are without 
such properties , but they all partake of the 
following characters 1 Ihey are mcombus- 



505 

tible, or do not unite with oxygen , 2 they 
are inferior to the metals in lustre and opacity , 
3. they are sparingly soluble m water , 4 they 
are difficultly fusible, or resist great heat with- 
out alteration, 5 they combine with acids 5 
6 they combine with each other, and with 
metallic oxides , and, 7 their specific gravities 
are from 1 to 5 

The latest attempt to decompose the earths 
is that of Mr Davy , he seems to have shewn, 
that some of the earths are analogous to the 
fixed alkalies, in respect to their properties of 
forming metals , but these metals, like those of 
the alkalies, are most probably compoqnds of 
hydrogen and the respective earths, 

1 Lime 

This earth is one of the most abundant , it is 
found in all parts of the world, but in a state 
of combination, generally with some acid 
When united with carbonic acid, it exists in 
large strata or beds in the form of chalk, lime- 
stone, or marble , and it is from some of these 
that lime is usually obtained 

The common method of obtaining lime, is 
to expose pieces of chalk or limestone in a kiln 
for a few days to a strong red or white heat , 
by this process, the carbonic acid is driven off, 



506 EARTHS 

and the lime remains tn compact masses of 
nearly the same si^e and shape as the lime* 
stone, but with the loss of ^ths of its weight 
It is probable, the intermixture of the lime- 
stone and coal in the combustion of the latter 
contributes, along with the heat, to the de~ 
composition The lime from chalk is nearly 
pure, but that from common limestone con- 
tains from 10 to 20 pei cent of foreign sub- 
stances, particularly aluminc, silex, and oxide 
of iron 

Lime thus obtained, which is commonly 
called quicklime, is white and moderately hard, 
but buttle Irs specific gravity, according to 
Kirwan, is 2 S It is corrosive to animal and 
vegetable substances , and, like the alkalies, 
converts coloured vegetable infusions, parti- 
cularly blue, into gieen It is infusible It 
has a strong attraction lor water, so as to rob 
the atmosphere of its vapour , when exposed 
to the atmosphere, it gradually imbibes water, 
and in a few days falls down into a fine white 
dry powder, in this process, it pure, it ac- 
quires 'H per cent in weight, after this, it 
begins to exchange its water foi carbonic acid, 
and carbonate of lime is slowly regenerated 
When 1 part of water is thrown upon 2 of 
quicklime, the lime quickly falls to powder 
with intense heat, calculated to be 800* (page 



LIME 507 

89) , this operation is called slaking the lime, 
and is preparatory to most of its applications , 
the new compound is denominated hydrate of 
lime, and appears to be the only proper com- 
bination that subsists between lime and water 
By a red heat the water is driven off and the 
lime remains pure 

As lime combines with the principal acids 
hitherto considered, and forms with them per- 
fectly neutral salts , and as the proportions of 
these salts have been experimentally ascertained 
with precision, we are enabled to determine 
the weights of an atom of lime thus, 

Acid Base 

Caibonate of lime, 44 + 56 percent as 19 24* 

Sulphate ^3 6 -f 41 4 34 24. 

Mitrate 619+387 38 24 

Muriate 47 3 -f 52 2 22 2* 

Carbonate of lime is, I believe, universally 
allowed to contain either 44 or 45 per cent of 
acid , and sulphate is mostly supposed to con- 
tain 08 per cent acid, the extremes bein^ 56 
and 60 Ihc proportions of the other two 
salts have not been so carefully determined f 
but it is easy to satisfy one's self that the pro- 
portions assigned are not wide of the truth 
I ct 13 grains of chalk, be put into 200 gram 
measures of the test nitric acid (I 143), or the 



508 EARTHS 

test muriatic (1 077), and it will be found that 
the lime will be wholly dissolved, and the 
acids saturated Hence it follows that the 
elementary atom of lime weighs 24 I have 
formerly stated it at 23, supposing carbonate of 
lime to be, according to Kirwan, 45 acid + 55 
lime per cent The difference is scarcely- 
worth consideration , but experience seems to 
warrant 24? rather than 23 for the atom of 
lime 

When a large quantify of water is thrown 
upon a piece of quicklime, it sometimes re- 
fuses to slake for a time , perhaps this is caused 
by the water preventing the rise of tempera- 
ture In this case the water does not dissolve 
the lime , hence it should seem that lime pro- 
perly speaking is not soluble in water, but 
hydrate of lime is readily soluble, though in a 
small degree The solution u> called lime- 
natei , ana is a very useful chemical agent 

Lime-water may be formed by agitating a 
quantity of hydrate of lime in water , distilled 
or ram water should be preferred One brisk 
agitation ib nearly sufficient to saturate the 
water , but if complete saturation is required, 
the agitation should be repeated two or three 
times After the lime has subsided the clear 
liquid must be decanted and bottled for use 
Authors differ as to the quantity of lime dis- 



LIME. 509 

solved by water some say that water takes 
^ of its weight of lime , others, T ^ The 
fact is, that few have tried the experiment 
with due care Dr Thomson* in the 4th ed 
of his chemistry says, from his experience, ^^ 
This is much nearer the truth than the other 
two One author says, that water of 212 
takes pp double the quantity of lime that water 
of 60 does, but deposits the excess on cool* 
ing no experimental proof is given If he 
had said half instead of double, the assertion 
would have been nearly true I haye made 
some experiments on this subject, and the re- 
sults are worth notice 

When water of 60 is duly agitated with 
hydrate of lime, it clears very slowly , but a 
quantity of the lime-water may soon be passed 
through a filter of blotting paper, when it be- 
comes clear and fit for use I found 7000 
grains of this water require 7i> grains of test 
sulphuric acid for its saturation Consequently 
it contained 9 grains of lime* If a quantity of 
this saturated water, mixed with h)drate of 
lime, be warmed to 130 and then agitated, it 
soon becomes clear , 7000 grains of this water 
decanted, require only 60 grains of test sul- 
phuric acid in order to produce saturation 
The same saturated lime-water was boiled with 
hvdrate of lime for two or three minutes, and 



510 EARTHS 

set aside to cool without agitation , it very soon 
cleared, and 700O grains being decanted, re- 
quired only 46 grams of test acid to be neu- 
tralized, the test acid being as usual 1 134. 
Hence we deduce the following table 

1 part takes up takes up of dry 

water of cf l^me hydrate of lime 

fyO^ * j -I ^ MW'^ f*r^* 4 

vv Tl9 j 8* \ 

130 f - 



This table leads us to conclude that water 
at the freezing temperature would take nearly 
twice the quantity of lime that water at the 
boiling temperature takes , I had not an op- 
portunity to try this m the season of these ex 
penments , but I am informed the calico- 
printers find a sensible difference in lime-water 
in different seasons of the year, and that in 
winter it is most subservient to their purpose, 
and least so in summer As water takes up so 
small a portion of lime, and cold water more 
than warm, one would suppose it u as the ef- 
tect of suspension rather than wlution With 
this view I tried whether the addition of a little 
gum to the water would not increase its solvent 
power , but the result was, that water ot 60 
took precisely the same quantit) ot lime, whe 
ther with or without gun J iound that a 
deep earthen vessel \\lnrh bad stood some 



L1MF 511 

months with lime-water exposed to the air, 
still contained ^ of its weight of lime 

Lime-water has an acrid taste, notwith- 
standing the small quantity of lime It operates 
on colours like the alkalies Certain blue co- 
lours, such as syrup of violets, are changed to 
green , infusion of litmus, which has been 
converted from blue to red by a little acid, 
has its blue colour restored by lime-water, and 
archil solut on, reddened by an acid, is restored 
to its purple colour by lime-water "When ex- 
posed to the air, lime-water has a thin crust 
formed on its surface , this is carbonate of 
lime, the acid being derived from the atmo- 
sphere , it is insoluble, and falls to the bottom , 
in time the whole of the lime is thus converted 
into carbonate, and the water remains pure 
If a person breathes through a tube into lime- 
water, it is rendered milky through the forma- 
tion of carbonate, or if water containing car- 
bonic acid be poured into it, but a double 
quantity of the acid forms a supercarbonate of 
lime, which is soluble in a considerable degree 
r l hough lime is soluble in water in so small a 
quantity, yet a portion of distilled water may 
be mixed with , ^ of l *s bulk of lime-water, 
and the presence of lime will be shewn by the 
test colours, or by nitrate of mercury, &c 

Lime combines with sulphur and with phos- 



512 EARTHS 

phorus these compounds will be considered 
under the heads of sulphurets and phosphurets 
It combines also with the acids, and forms 
with them neutral salts Lime unites to certain 
metallic oxides, particularly those of mercury 
and lead , but the nature of these last com- 
pounds is not much known 

One of the great uses of lime is in the for- 
mation of mortar In order to form mortar, 
the lime is slaked and mixed up with a quan- 
tity of sand, and the whole well wrought up 
into the consistence of paste with as little water 
as possible This cement, properly interposed 
amongst the bricks or stones of buildings, gra- 
dually hardens and adheres to them so as to 
bind the whole together This is partly, per- 
haps principally, owing to the regeneration of 
the carbonate of hme from the carbonic acid 
of the atmosphere The best ingredients and 
their proportions to form mortar for different 
purposes, do not seem vet to be well un- 
derstood 



C 2 Magnesia 



I his earth is obtained from a salt now called 
sulphate of magnesia, which abounds in sea- 
water and in some natural springs Accoiding 
to the best anahse&j crystallized sulphate of 



MAGNESIA* 513 

magnesia consists of 56 parts of pure dry sul- 
phate, and 44 parts water in the hundred. 
Some authors find more water in this salt ; 
namely, from 48 to 53 per cent , but Dr. 
Henry, in his analysis of British and foreign 
salt, in the Philos Trans 1810, takes notice 
of a crystallized sulphate of magnesia contain- 
ing only 44 per cent water , and the specimen 
of sulphate which I have had for many years 
bears the same character I am, therefore, 
inclined to adopt this as the true proportion of 
water Now, Dr Henry found that 100 grains 
of the above sulphate of magnesia produced 
111 or 112 grains of sulphate of barytes, and 
it is well established that 4 of this last salt is 
acid , hence, the sulphuric acid in 10O sul- 
phate of magnesia (56 real) is equal to 37 
grains , consequently the magnesia is equal to 
19 grains but the weight of an atom of sul- 
phuric acid is 34 , therefore, 37 19 34 17, 
nearly, which must be the weight of an atom 
of magnesia, on the supposition that sulphale 
of magnesia is constituted of one atom of acid 
united to one of base, of which there is no 
reason to doubt I have in the fint part of 
this work, page 219, stated the weight of mag- 
nesia to be 20 , it was deduced chiefly from 
Kirwan's analysis of sulphate of magnesia , but 



514 EARTHS 

from present experience I think it is too high 
Though few of the salts of magnesia have been 
analyzed with great precision, yet the weight 
of the atom of magnesia derived from different 
analyses would not fall below 17, nor rise 
above "20 Dr Henry and I analyzed the 
common carbonate of magnesii well dried m 
100, and found it to lose 4O per cent by acids, 
and 57 per cent by a moderate red heat Hence 
it should consist of 43 magnesia, 40 carbonic 
acid, and 17 water We found the carbonate 
begin to give out water and some acid about 
430 , but it supported a heat of 550 for an 
hour without losing more than 16 per cent 
Hence the carbonate must be constituted of 1 
atom of acid, 1 of magnesia, and 1 of water, 
stating the magnesia at 20 , for, 19 + 8 4- 20 
= 47, and if 47 19, 8, and 20 100 40, 
17 and 43 respectively, according to the above 
experiments I have reason to think, however, 
that the weight of the atom of magnesia ought 
rather to be deduced from the sulphate than 
the carbonate y because it is probable that this 
last always contains a small portion of sulphate 
of lime, when prepared by the medium of 
common spring water, this portion will be 
found in the result of the analysis by fire, and 
be placed to the account of magnesia 



MAGNESIA* 515 

Wherefore 1 conclude the weight of an atom 
of magnesia to be 17 It is said that a super- 
carbonate of magnesia is obtainable , but when 
sulphate of magnesia and supercarbonate of 
soda in solution are mixed together, there is a 
great effervescence and disengagement of car- 
bonic acid, and nothing but the common car- 
bonate of magnesia is precipitated according 
to my experience Dr Henry, indeed, ob- 
tained a crystallization by exposing a dilute 
mixture for some time , the crystals were small 
opake globules, about the size of small shot , 
but upon examination, they proved to be no- 
thing but carbonate of magnesia united to 3 
atoms of water instead of 1 atom For, 100 
grains lost 70 by a red heat, and 30 by acids , 
whence its constitution was 30 acid + 30 earth 
+ 40 water, or 19 acid + 19 earth + 24 or 25 
water The constitution of crystallized sul- 
phate of magnesia must, therefore, be 1 atom 
of acid + 1 atom of magnesia + 5 atoms of 
water , in weight 34 + 17 + 40 = 91 , this 
gives per cent 37 acid 4- 19 base + 14 water, 
agreeably to Dr Henry's experience above- 
mentioned 

The constitution of the most common salts 
of magnesia, in their dry state will, therefore 
oe as under 



516 EARTHS. 

Acid Bate 

Carbonate of magnesia 53 + 47 per cent, as 19 I? 

Sulphate 66 7 + 33 3 34 17 

Nitrate 69 4- 31 38 17 

Muriate 56 4 + 43 6 22 17 

The nitrate of magnesia m the above table 
agrees with that of Kirwan, and Richter, and 
the muriate with that of Wenzel 

To obtain magnesia* the sulphate must be 
dissolved in water, and a quantity of pure pot- 
ash in solution must be added , the magnesia 
is then thrown down, and may be separated 
by filtration Or if carbonate of potash be put 
into the solution of sulphate of magnesia, car- 
bonate of magnesia will then be precipitated, 
which may be separated by filtration , this last 
must be exposed to a red heat to drive off the 
carbonic acid , the former need only to be 
dried in a gentle heat 

Magnesia is a white, soft powder, possessing 
little taste and no smell , its specific gravity is 
said to be 2 3 It operates on vegetable co- 
lours like lime and the alkalies It is infusible 
by heat, and very sparingly soluble m water 
According to KirV\ an, it requires 700O times 
its weight of water to dissolve it , I found it 
require 16,000 times its \\eight of water m 
one expeument AVhen exposed to the air, 



MAGNESIA 



517 



magnesia, like lime, attracts 1 atom of water 
to 1 of magnesia, amounting to about 47 per 
cent by my experience $ it attracts carbonic 
acid but very slowly It does not combine 
with any of the simple substances, except per- 
haps hydrogen and sulphur With the acids it 
forms neutral salts, which are found frequently 
to combine with other salts 

As the sulphate of magnesia is the ordinary 
combination of this earth exhibited as a soluble 
salt, it may be of use to have a table Chewing 
the quantity of real dry sulphate, and of ordi- 
nary crystallized sulphate, in given weights or 
measures of solutions of different specific gra- 
vities The table is founded on my own ex- 
perience 

Table of sulphate of magnesia 



Atoms* 
Mag Water 


Dry sulphate 
of magnesia 
per cent by 


Dry sulphate of 
magnesia per cent 
sy mc9 ure 


Common crystal 
hzed sulphate of 
mag per cent by 


Specific f rv!tv 




weight 




measure 




I + 


100 








1 + 5 


50 


>3 


166 


66 sol 


1 + 8 


444 


666 


no 


50 liq 


1 +10 


19 


554- 


9Q 


42 


1 +15 


30 


39 


696 


30 






31 


55 


25 






24 


428 


20 






18 


32 1 


15 






12 


21 4 


1C 









107 


i 05 



The fifth hydrate is the ordinary c~ystalliz<?d 
sulphate , the eighth is the strongest liquid so- 



518 EARTHS 

lution obtained by boiling , and the fifteenth is 
a saturated solution at 60 



3 Batytes 

The earth now denominated baryte$> was 
discovered by Scheele in 1774 Since then 
the labour and experience of several distin- 
guished chemists have added much to the 
knowledge both of the earth and its com- 
pounds , so that now it may perhaps be said 
to be the best understood of all the earths It 
occurs most trequently m combination with 
sulphuric acid, the compound being called 
sulphate of barytes, formerly ponderous spar, 
and is found about mines, particularly of cop- 
per It also occurs in combination with car- 
bonic acid, though rarely , the compound is 
denominated carbonate of ba rytei 

Barytes may be obtained either from the sul- 
phate or the carbonate The former must be 
pulverized, mixed with charcoal, and exposed 
in a crucible to a red heat for some hoius , the 
sulphate is thus changed into a sulphuret This 
sulphuret is to be treated vvith nitric acid, 
when the sulphur is thrown down, and the 
barytes combines with the acid , the acid mav 
then be driven off by a red heat and barvtcs 
remain in the crucible It the carbonate 



BARYTES. 519 

be used, it must be pulverized, mixed with 
charcoal, and exposed for some time in a cru- 
cible to the heat of a smith's forge Boiling 
water will then dissolve the pure barytes, leav- 
ing the charcoal and carbonate, and upon 
cooling, crystals of hydrate of barytes are ob- 
tained The greatest part of the water may 
be driven off by heat 

Pure barytes obtained by the former method 
is a greyish white body, easily reduced to 
powder It has a harsh and caustic taste, and 
if swallowed proves poisonous Like lime, 
when exposed to the atmosphere, it absorbs 
water, and then parts with it for carbonic 
acid It changes certain vegetable blues to 
green Its specific gravity is neatly 4 Ba- 
rytes forms various combinations with water* 
called hydrates, which will presently be men- 
tioned It combines with sulphur and phos- 
phorus, but not with the other simple sub- 
stance The sulphuret and phosphuret will 
be considered under their respective heads 
The weight of the ultimate panicle of barytes 
can be very nearly approximated, and appears 
to be 68. or twice the weight of an atom of 
sulphuric acid This appears from the follow- 
ing statement of the proportions of the most 
common bzrytic salts, whicn have been suc- 
cessfully investigated 



520 EARTHS 

Acid* Ewe. 



* . 

Carbonate of barytes 22 +78 percent as 19 6$ 

Sulphate -- 33 3 + 66 7 -- 34 58 

Xntrate - 36 + 64- -- 38 68 

244+756 -- 22 68 



The following respectable authorities agree 
in assigning 22 per cent acid to carbonate of 
barytes , namely, Pelletier, Clement, Desor- 
jnss, Klaproth, and Kirwan , and more re- 
cently Mr. Aikin finds 21 67, and Mr James 
Thomson, 2175 (Nicholson's Journal, vol 22 
and 23, 1809) The last mentioned chemist 
findb sulphate of barytes to be 33 acid, and 67 
barytes. His conclusion corroborates the pre- 
vious ones of Withering, Black, Klaproth, 
Kuwan, Bucholz, and Berthier> who all fix: 
the acid at or near 33 per cent Vauquelm, 
Rose, Berthollet and Fhenard and Clement 
and Desormes find 32 or more acid , and Four- 
croy and Aikin, 34 It is very satisfactory to 
see the near coincidence in regard to the con- 
stitution of this salt , because it is frequently 
made a test of the quantity of sulphuric acid 
and of sulphur Mr J Thomson finds 59 3 
barytes per cent in nitrate of barytes, Clement 
and Desormes 60, Kirwan 58 and 55 at dif- 
ferent trials, and Fourcroy and Vauquelm 50 
These results differ considerably from each 
other, and are all below the proportion as- 



BARYTES 52 \ 

signed above 3 but it must be observed that 
crystallized nitrate of barytes contains water, 
and perhaps various quantities of water ac- 
cording to the temperature in which it crystal- 
lizes , now, if the atom of nitrate be associ- 
ated with 1 atom of water, then the proportion 
of barytes per cent will be 59 6, which nearly 
agrees with Thomson, and Clement and De- 
sormes , if with 2 atoms of water, the barytes 
will be 55 7 percent 3 If with 3 atoms, then 
52 3, &c -* Crystallized muriate of barytes ap- 
pears clearly to consist of an atom of dry mu- 
rjate + 2 atoms of water , or 22 acid + 68 
barytes + 16 water, this reduced gives 208 
acia + 64 1 barytes 4-151 water per cent 
For, Kir wan finds 20 acid + 64 base + 16 
water , Fourcroy, 24 acid + 60 base +16 wa- 
ter, and Aikm, 22 9 acid + 62 5 base +146 
\\ater per cent , which agree with each other, 
and with the theory as nearly as can be ex- 
pected 

Rarytes combines with most acids, and forms 
with them neutral salts In many respects it 
appears to he related to the fixed alkalies, only 
m weight it is nearly the same as both of them 
put together 



522 EARTHS* 

Hydrate gf Barytes 

When pure barytes, obtained from the ni- 
trate by heat, is exposed to the air, or is moist- 
ened by water, it combines with it, and that 
in various degrees, forming a number of hy 
drates, which have not been sufficient!} at- 
tended to and discriminated , much heat is 
evolved during the combination it was mis- 
taking the first hydrate of barytes for pure ba- 
rytes that caused the uncertainty for some time 
in regard to the proportions of the elements of 
sulphate of barytes (see page 474) Now, if 
an atom of barytes weigh 68, the first hydrate 
will weigh 76, to which if 34- sulphuric acid 
be added, we shall ha\e an atom of sulphate 
of barytes = 102, (for the water is driven off 
by the union of the acid and base) , if then we 
conceived the hydrate to be pure barytes we 
should conclude that 76 barytes united to 26 
sulphuric acid to form 102 sulphate, which is 
very near the former mistaken conclusion of 
Thenard and Berthollet Hence then there 
is reason to conclude that their barytes, kept 
some time in a red heat, was in reality the first 
hydrate, or one atom of barytes and one of VIM- 
ter When pure barytes is dissolved in boiling 
water, a solution is formed of specific gravity 



H\ DRATE OF BAR* TES 523 

exceeding 1 2 , on cooling, great part of it 
crystallizes , these crystals are the twentieth 
hydrate, or consist of 1 atom of barytes and 20 
of water, or 30 barytes and 70 water per cent ; 
if they are expend to a heat about 400 or 500% 
they melt, great part of the water is dissipated, 
and a dry white powder is obtained, which is 
titejifth hydrate In this operation, 223 part* 
(= Q9 + 20 X 8) are reduced to 108 (=68 4- 
5 x 8), or 100 to 47, which is exactly the re- 
duction obtained experimentally by Dr Hope 
This dry powder melts below a red heat , but 
I have not been able to find what it would be 
reduced to by exposure to a red heat, because 
it acquires carbonic acid, even in a crucible, 
as Berthollet has observed, almost as fast as it 
loses water My experience on the crv stals of 
barytes has been limited , but from the follow- 
ing I conclude they are the twevttieth hydrate 
1 tock 80 grains cf fresh crystallised barytes, 
and dissolved them in 1000 grains of water, 
the solution was of the specific gravity I 024 , 
this solution took 70 grain measures of test sul- 
phuric acid to saturate it, and afforded 36 grams 
of dried sulphate of barytes of this )2 grams 
were acid and 24 barytes Whence we learn, 
1st, that 80 grams of crystals are equal to 24 
real barytes, or 22S equal to 68 , but 228 ~ 
20 X 8 + 68, which shews that 20 atoms < I 



524 



EARTHS* 



water are united to 1 of barytes, 2d, that the 
decimals in the second and third places of the 
expression for the specific gravity, denote the 
quantity of real barytes in 1000 gram measures 
of the solution This last must evidently hold 
without any material error in all the inferior 
solutions , and hence the strength and value of 
barytic water may b* knowp by its specific 
gravity, an advantage which does not practi- 
cally appertain to htne water By subsequent 
trials^ however, I found the quantity of barytes 
rather overrated 

The following sketch of a table of the hy- 
drate of barytes may have its use, till a more 
ample and correct one can be constructed 

Table of the Hydrate of Baryta 



Atoms 
Baryt Water 

1 + 

1 -1. 1 


Barytes per 

cent by 
weight 

100 
on 


iarytes per pert 
by measure 

400? 


Specific gravny 

4 00 * so! 


Congealing point* 

unknown 


J -f- J 

1 I *i 


f\i 








1 -|" 

1 + 20 
1 + 30 

1 + 275 


30 
19 
26 
1 8 
tf 


48 
25 
27 

i S 
00 


1 o . 
1 3 fl 

1 03 ~* 
1 VI 
I Ul 


200? 
150 ? 

40 > 



4 Sti unities 

The mineral from which this earth is ob- 
tained was first found in the lead-mine of Stron- 
tian m Argyleshire, Scotland The earth and 

* This is a situiated solution in the mean temperature 
of 60*. 



STRONTITES 525 

its distinguishing properties, were pointed out 
by Dr Hope in an essay read to the Royal 
Society of Fdirbi, gK in 1792, and published 
in their Transactions, 1794- Several distm* 
guished chemists have since confirmed and ex* 
tended these investigations The Scotch tni* 
neral is a carbonate of strontites , but the earth 
has since been found in various parts combined 
with sulphuric acid 

Strontites is obtained from the sulphate or 
carbonate of strontites, by the same processes 
as barytes from the like compounds, indeed, 
it bears so close a resemblance to barytes, both 
in its free and combined state, as to have been 
confounded with it Strontites has much the 
same acrid taste as barytes , but it is not poi- 
sonous , it is less soluble in water than barytes , 
it has the property of giving a red or purple 
colour to flame, for which purpose the nitrate 
or muriate may be dissolved in alcohol, or ap- 
plied to the wick of a candle The weight of 
the atom of strontites is deducible from the sa'ts 
which it forms with the more common acids to 
be 46 Ihu5, 

Aad Bajf 

Caibonatc of strontites W 2 -f- 70 8 per cent as 19 46 

Sulphate U J + S7 5 31- 4S 

N, lri te - 4-5 2 + j* 8 ^ 46 

Murilte 32 4- + 67 G 22 46 



526 EAftTHS. 

Dr Hope, Pelletier, and Klaprpth Jrad SO 
per cent of acid in the carbonate Klaproth, 
Clayfield, Henry, a?nd Kirwan find 42 per cent* 
acid in the sulphate Kirwan finds the crys- 
tallized .nitrate to contain 31 07 acid, 3621 
base, and 32*72 water, which I ptesume de- 
notes 1 atom of acid, 1 of base, and 5 of wa- 
ter , that is, 38 acid 4- 46 base + 40 water , 
this reduced, would give 30 6 acid, 37 1 base, 
and 32 3 water per cent which very nearly 
agrees with his experience Taking the dry 
salt, his results would give 46 2 acid, and 53 S 
base Vauquelm finds the nitrate to contain 
48 4 acid, 47 6 base, and 4 water, but this 
constitution cannot be correct Neither can 
Richter's analysis, which gives 5 1 4 acid and 
water, and 48 6 base Dry muriate of stron- 
tites, according to Kirwan, consists of 31 acid, 
and 69 base, but Vauquelm states 39 acid, 
and 61 base , the former, without doubt, is 
nearer the truth 

Hydrate of Strontites When water is put 
to pure strontites, it becomes hot and swells, like 
lime and barytes, anc* falls into dry powder 
This powder seems to be the fiist hydrate , 
whence, 46 parts of Strontites will take 8 of 
water to form this combination , but if more 
water be added, the hydiate crystalh/cs 
Ibese crystals appear to be the 12th h\drate > 



ALITMINE 

that is, they are constituted of 1 atom of stron- 
tites and 12 of water #6 + 96 = 142, or 32 
strontites + 68 water per cent agreeably to 
the experience of Dr Hope, Water dissolves 
about -ryryth of its weight of pure strontites m 
the temperature of 60% or yVth of its weight 
of the crystals , the specific gravity of the solu- 
tion is nearly 1 008 But boiling water dis- 
solves about half its weight of the crystals. 
Whence it appears that strontites is much less 
soluble than barytes, and much more soluble 
than kme. The specific gravity of the crystals 
of strontites is rightly determined by Hassen- 
fratz to be nearly 1 46 Strontian water may 
be used for the same purposes as lime-water, 
or barytic water 

Strontites combines with most of the acids to 
form neutral salts It also combines with sul- 
phur and phosphorus 



5 Alummt) of Argil 

The earth denominated alumme, constitutes 
a gr