'rh

MEMOIRS

LITEEARY AND PHILOSOPHICAL SOCIETY

MANCHESTER

^:t//. 4. /^

MEMOIRS

LITERARY

PHILOSOPHICAL SOCIETY

MANCHESTER.

^econly Setter*

VOLUME THIRTEENTH.

LONDON :

H. BAILLIERE, 219, REGENT STREET,

AND 290, BROADWAY, NEW YORK.

PARIS: J. B. BAILLIERE, UBRAIRE, RUE HAUTEFEUILLE,

1856.

MANCHBSTKR :
PRINTED BV T. «OWi.KR AND SONS, ST. ANNS SQUARE.

-^ >-r-<^

MEMOIll

JOHN DAL TON

D.C.L., F.R S.,

INSTIT. (ACAD. 8C.) PAllIW. H0CIU8.,

PaESTDENT OF THE LITBUARY AND PUILOBOl'HICAL 80CIBTY OF

MANCHUSTBtt, ETC., ETC. J

HISTORY

OF

THE ATOMIC THEORY

UP TO HIS TIME.

BY

ROBT. ANGUS SMITH, PH.D., F.C.S.

SEC. TO THE LIT. AND PHIL. SOC.

LONDON:

H. BAILLIERE, 219, REGENT STREET,

AND 290, BROADWAY, NEW YORK.

PARIS : J. li. BAILLIERE, LIBRAIRE, RUE HAUTEFEUILLE.

ISoG.

NOTE.

In this, as in the previous Volumes, the Society
is not to be considered responsible for any statements or
reasonings offered.

PREFACE

The life of Dalton has already been written, but chemical
literature seemed to demand a more minute history of
the atomic theory up to his time, without at all dis-
paraging the valuable history of chemistry by Dr. Kopp,
or the work of Dr. Daubeny, which treats principally
of the more modem part. For this and reasons else-
where mentioned, I have made . the distinctive feature of
the volume the history of our ideas of matter bearing on
modem chemistry, until the time when Dalton flourished.
There is a short memoir which breaks off at the fourth
chapter, <yt the time when Dalton first published on atoms,
in order to begin the general history, which again leads
to Dalton at the eleventh chapter.

Mr. James Woolley 'was kind enough to lend me
all the papers relating to Dalton which he possessed,
together with his own MS. memoir, and Mr. Giles,
with similar kindness, lent me the memoir which he
had written. Dr. Henry's volume also has not been

VIU PREFACE.

neglected. Mr. Isaac Dickenson, of Cockermouth, and
Mr. Thomas Bewley, of Bassenthwaite, have also fur-
nished me with interesting letters.

It might have heen expected that more attention
would have been given to Dalton*s private life, living,
as I am, among so many who knew him, but none
with whom I have conversed have given any important
information not here embodied. I considered also that
Dr. Henry had very fully treated that subject, and that
it would be unwise and wanting in respect to go over
the same ground exactly, even when the same materials
were supplied, I have therefore been minute only in
such things as did not appear to me elsewhere treated,
or such as seemed the most characteristic according to
my ideas.

The history of Dalton's many scientific inquiries on
subjects other than the atomic theory, is given so shortly
that it might almost have been left out, did it not give
a greater completeness to the memoir, for the use of such
as read no other life of the same man. The history of
our ideas of matter is one of the most interes^ng "fairy
tales of science," it is a pity that, like so much else in
science and philosophy, it should be so frequently spoiled
by dryness. The desire to avoid this has led me to extend
further than usual the meaning of the title. The plan of
quotation instead of description has been adopted, as
the most just as well as the most interesting, if well
managed, althoup^h one which may gradually be allowed

PREFACE. ix

to degenerate into mere extractive matter. Every worker
and thinker is allowed to speak for himself, and there
are few allusions made to the opinions of any, however
eminent, who has not himself laboured on the subject.
In the court of science every man is his own best
witness ; by using description instead of quotation we
employ advocates who bandy about the meaning, until
at last it can nowhere be found. We cannot be too
careful of the fame of the absent, were it merely to
protest against the loud assertion of self, which is so
easy for those who are present, even when their only hope
of fame lies in that two-edged truth, that "a living dog
is better than a dead lion."

ERRATA.

Near bottom of page 77, the inverted commas should begin, ** For one is not
the same."
Page 79, for air and matter^ read air and water.
Page 251, for John Qough W., read ffeiiry Hough W.

CONTENTS.

PAOB

Preface vii

CHAPTER

1 1

Dalton's Early Life and First Book 4

II. His Epoch of greatest fertility 27

III. Dalton's Social Life 51

HiSTOKY OF THE AtOMIC ThEORY.

IV. Ideas of Matter up to the time of Lucretius 74

V. From Lucretius till the decay of Alchemy 98

VI. Opinions during the transition from Alchemy to

Chemistry 117

VII. Phlogiston Period and Progress of the Balance 142

VIII. Dr. Bryan Higgins and William Higgins 167

IX. Richter 186

X. Fischer, Berthollet, Proust, &c 216

XI. Dalton's Atomic Theory 230

XII. Later Life of Dalton 247

XIII. Dalton's Intellectual Character 283

XrV. Arrangement of Theories 288

Index 293

MEMOIRS

OF

®6e ititerara auK J)i)(loj5opfi(cal &ocUtSi of
inancj^e^Ur*

MEMOIR OF DR. DALTON,

AND

HISTORY OF THE ATOMIC THEORY.

[Read October 2nd, 1856.]

CHAPTER I.

In 1789, when this Society was first established, chemistry
could not with propriety be called a science, although
Lavoisier was attempting to decide on some of its more
prominent laws, and although Cavendish, Black, and Watt
had raised it from that position of obscurity to which the
meagreness of its results had so long condemned it, and
shewn to the world that it possessed a power, apparently
the highest in order. With the exception of these and a
very few others, the whole body of its students were under
the subjection of one of the strangest delusions that has ever
usurped the place of a law of nature. A body of men for
many ages at work had made so little progress towards
eliciting definite forms of thought upon the elements with which
they worked, that the theory of Phlogiston was regarded as
a great discovery ; a fanciful theory founded on an explanation

2 MEMOIR OF DR. DALTON, AND

of facts confessedly incomplete in the eyes of the most
enlightened, was made the great centre round which all
chemical knowledge placidly rolled. We may be allowed
to boast, that, when this society had existed only a few
years, one of its members was found to devise a theory
which not only was sufficient to throw light on the past,
but at once to put into the infinite observations of his pre-
decessors that reason and order of which before they seemed
totally deprived. The hermetic mystic and alchemist had
toiled over the difficulties, had tried to remove them by
physics and by metaphysics, had explained them by supposing
an independent will in the elements or by the immediate
Divine interposition ; by their wildest imaginings and their
clearest reasonings little definite had been attained. The
laws which Dalton shewed us to be dominant in matter,
considered chemically, were at once clear enough to satisfy
the most exact reasoner, great enough to satisfy the most
poetical thinker, and simple enough to satisfy those who
believe that, at least the great primary laws of nature are
simple, whether because the highest wisdom can of course
attain its ends with the greatest ease, or because the simplest
germ is more easily fitted to branch out into an' endless de-
velopment of character and power.

It is scarcely possible to write the life of Dalton without
referring to this Society, and as it is by request of this body
that I have undertaken to write, I must explain to them
what I have specially attempted to do. After Dr. Henry
had written the life of Dalton, it might fairly be asked why
I should undertake one. I was requested to write this
memoir at a time when it was uncertain when Dr. Henry's
would appear. I was unwilling to compete with Dr. Henry,
and saw no propriety in doing so, although he offered me his
materials on certain fair conditions. I had no intention to
write a complete life, nor, I believe, had the society the desire
to have a memoir so large as that which I present, and I

HISTORY OF THE ATOMIC THKOKY. 3

considered it better to confiiic myself to certain aspects of
Dalton's life and discoveries, thus preventing any reason for
asking why another memoir should have at all appeared. The
portion which I have most carefully worked out is the History
of the Atomic Theory. Much has been said of it; some have
g^ven the credit to Dalton, some have taken it from him;
most writers have confusedly mixed him up with others*
Some have looked forward to the probable developments of
truth in after times, and undervalued the laws of combination
as they now stand, and with them the discoverers. It has
been my desire to shew distinctly what of importance each
celebrated thinker or worker has said or done in the matter
before Dalton, and what he has himself accomplished. This is
done by bringing the original words of the authors, and
endeavouring to find what amount of meaning can be at-
tached to them. As for all future developments of the
present laws I can only say that, believing as I do in the
infinite wisdom with which creation is ordered, I am ready
to believe in infinite developments of any law ; but strange
as may be the new and possible combinations of elements,
and interesting also the breaking up of these our present
elements into other elements, or even into mere pieces, it is
not to be imagined that even nature has any thing in store
for us fitted to answer the same purpose within the same limits
and still simpler and more extensive than the laws of com-
bination as Dalton has expressed them.

Of the man it has been attempted to give only a short
sketch, and the whole merely to serve as an enlarged epitaph,
written here instead of on his tomb, a token of remembrance
for ourselves especially, like the coffin of some departed friend
to preside at our feasts, and as a contribution to his defence if
he should be assailed.

It will also be more in accordance with his own life if little
is said about his personal affairs, which took such a very
inferior place in his occupations. Unlike many men of the

4 MEMOIR OF DR. DALTON, AND

greatest attainments, Dal ton was little occupied with those
numerous incidents closely relating to family and friends,
which, although productive of much true happiness, capable
equally of enlarging the smallest minds and deepening the
influence of the most gifted, involve the consumption of much
time, a loss much deplored as often as we consider how little
we have, and how much is needful in order to obtain from
nature even the smallest addition to our knowledge. For
Dalton, science was the occupation of life, of a life spent in
the most laborious manner. The amenities of life came to him
as memories of what had been in his childhood rather than as
pleasures realized at the time, memories certainly which he
willingly recalled, but as willingly, or perhaps resolutely, left,
because his work was before him. He was a student of
nature from his cradle.

Few as the materials for his early life are, and bare as are
all the narratives, we have perhaps all that could really be
found to be interesting. To all appearance he was like those
around him, born to be a clodhopper, few things happening
to fix the attention of others upon him, no incidents worth a
record, because happening to millions daily; the first years
must be passed with a simple record of the meagre living and
the scantier education he received, until the glow of his life
became warmer than that of his fellows. From that time his
life is almost entirely in his works, like a devotee who has no
heart for the world, but for Divine truth only, his very visits
to his early friends were visits as much made for the inves-
tigation of truth, made to nature under that aspect which
first taught him to observe and to think, which in fact first
made him a philosopher and the love of which he never for a
moment lost.

John Dalton was born at Eaglesfield, in Cumberland, on the
5th of September, 1766, in a small cottage on the estate of

HISTORY OF THE ATOMIC THEOBY. 5

the family, which had come into their possession through his
maternal grandmother. His father at this time was a woollen
weaver, and did not live in the house belonging to the pro-
perty, but in a cot of his own, having two small rooms below,
one some ten feet square only, and the other still less. The
larger house was afterwards, on the death of his uncle, occu-
pied by the father. It is described as one of the better class
of farm houses of the district, and is still in possession of the
family in a somewhat modernized state. The village of
Eaglesfield is 2j miles south-west of Cockermouth. The
whole township contains only 371 inhabitants. His father,
Joseph Dalton, was very poor, in fact he earned only a scanty
subsistence by weaving common country goods, and his wife
eked it out by selling paper, ink, and quills,* but he seems to
have been a man of some vigor of mind, as we find that he
taught his sons mathematics, giving them such an education
at least as is included in mensuration and navigation.! He
afterwards inherited the estate, his brother having died
childless. He then gave up weaving. It was by a similar
occurrence that the property long afterwards came into the
possession of Dr. Dalton, and afterwards into the hands of
his cousins on the mother's side.f Of the Daltons, or the
relatives by the father's side, yeomen or small proprietors in
Cumberland, we can find little information; his mother,
Deborah Greenup, through whom the property came, con-
nected him with many families in the neighbourhood. She
was the third daughter of a family of one son and seven
daughters, living at Greenrigg, Caldbeck. The son was a
barrister, and practised in London, but having inherited
Greenrigg, retired to it, living there to an advanced age,
having no children, and leaving the property to his unmarried
sister, Ruth. This aunt of Dr. Dalton left the estate of

• Mr. Bewley'8 Letter. f Mr. Woolley.|
X This estate was of about sixty acres, but Dalton's elder brother Jonathan
increased it considerably by purchase.

6 MEMOIR OF DR. DALTON, AND

Greenrigg to be divided equally between Jonathan and John
Dalton and their cousin, George Bewley. The estate was
small and in a mountainous district, so that when sold in
1817 or 18, it brought only £750.*

I shall give in a note the names of his aunts the Green-
ups and their families, as their children the cousins of Dr.
Dalton were most affectionately looked on by him during
his whole life, as well as kindly and liberally remembered in
his will.f

Jonathan Dalton, the grandfather, joined the Society of
Friends, and the family continued with that body, a circum-
stance that no doubt in a considerable degree influenced the
habits and character of Dr. Dalton.

Joseph Dalton and Deborah Greenup had three children,
Jonathan, John, and Mary. The sons were taught mathe-
matics, partly we are told, by the father, but they were also
sent to Mr. Fletcher, the teacher of the school belonging to
the Society of Friends. Eaglesfield was early connected with
this society, and is said to have first built a meeting house
for that body. In Mr. Fletcher's school John remained until
twelve years of age, and during that time he must have
made great progress, as we find him immediately beginning
to teach. He always spoke with great admiration of Mr.
Fletcher, who lived until Dalton himself was advanced in life.
Indeed we have no reason to think that even in that small

• Mr. Bewley's Letter,
f Eldest daughter of Greenup family married to Samuel Bristo ; many de-
Bcendents, particularly Rachel and Margaret Lickbarrow, of Kendal, to whom
Dalton left legacies. (There was a third, Isabella, living at Dalton's death.)
Second daughter married to Thomas Bewley, whose only son was George
Bewley, of Woodhall, who formerly had the school in Kendal. The grandson,
Thomas Bewley, of Bassenthwaite, to whose letter I am indebted for a history
of the whole family, has daughters married to Mr. Abbatt, of Liverpool, and
Mr. Benson, of Preston, who went in the funeral procession as nearest of kin to
Dalton, and who by his will received legacies. The fifth married to Mr.
Dickinson, whose descendent's letter I have quoted. The sixth married in the
north of Scotland; whilst the seventh is mentioned in the text.

HISTORY OF THE ATOMIC THEORY. 7

place a teacher of ability could not be found. There are other
parts of Cumberland, the parish of Martindale for example,
where the science of mathematics was well taught in the days of
our grandfathers, but where both scholars and instruction in the
most elementary English books could with difficulty be had
within these three years. Dalton must certainly have sur-
passed the other scholars when he began to teach at the age of
twelve. The school was kept in the Friends' Meeting House,
at Eaglesfield, still a school-room.* We are not told if he
succeeded his teacher in this, or where Mr. Fletcher after-
wards lived. We may picture to ourselves the struggles of
the determined boy, working hard at his father's farm in the
summer time, as we are informed he did, and helping also
to repair the old farm house, but working with still more
determination in winter which afforded him the chief oppor-
tunities for study, and when the boys from the various farms
congregated to the school, their parents not being able to
spare them from their work during the busy season of the
year. We can picture the indomitable youth, as an old
pupil of his, John Robinson, now living at Eaglesfield,
has pictured him, struggling for that authority needed to
maintain order, but feeling that there was no struggle needed
to shew the superiority of his information. Being as old or
older than himself they would not be silenced or commanded,
and determined as himself they challenged him into the
surrounding grave-yard to fight. It is not said whether he
accepted the challenge, but he sometimes took the more
dignified mode of locking-up the more refractory, repeating
in the school-room that they might learn their tasks whilst
he went to his dinner. For this, however, he waS sometimes
at least the greatest sufferer, as they broke the windows in
revenge.f

• Pens and ink were announced as to be sold within.
I From Mr. Dickinson's Letter.

8 MEMOIR OF DR. DALTON, AND

Occupied in teaching and in the work of the farm he kid
the foundations of an active mind and raised up a vigorous
well-knit frame, which underwent great exertion till an ad-
vanced age with little interruption from ill health. Here
we see the self-reliance which was strong in him through
life; at an age when most persons are mere children, he
sought to some extent to rule ; and when most persons have
scarcely begun to learn soundly, he sought to teach. Here,
also, we see that peculiarity of his mind, which did not seek
to acquire a great mass of information otherwise than by
investigation, and had more pleasure in making use of what
it had attained either by conveying it to others, or as a tool
for search. These united causes throw some light on his
early grasp at independence, as it was not necessity that
compelled him to work, nor the want of the means of living
which had never failed him.

As we are obliged to arrive at his early character chiefly
by inference, we must the more carefully remember, what is
more directly told of him, his great diligence. This con-
tinued with him through life, and his theory of success was
made in the belief that diligence constituted the main dif-
ference amongst men engaged in intellectual pursuits. His
principal study in early life was mathematics, which he
learned with a boy of the name of William Balderstone,
receiving assistance from a gentleman in the neighbourhood
of the name of Robinson, who fortunately had education as
well as property. He and his accomplished wife readily gave
their assistance in conducting the studies of Dalton, and his
companion who was in their service. These boys filled
with "emulation solved problems in numbers and in forms, as
active minded boys still do over all the country. Balder-
stone bet Dalton sixpence on a proposition in geometry, but
Mr. Robinson objected, and proposed rather that whoever
lost should supply the other with candles during the winter.
Dalton's answer is generally said to be, <« yan might do it,"

HISTORY OF THE ATOMIC THEORY. 9

for although his parents had got over one of their early diffi-
culties, that of "keeping him out of the dubs," they had not
yet taught him to speak other than his native dialect, which
he not unfrequently used also in later life, thereby giving
pith or humour to his conversation. We scarcely know if
the mention of " dubs" means that he was fonder than other
children of such things, or whether his love of nature first
took its rise in this common although unpromising amuse-
ment.

This acquaintance with Mr. Robinson began when Dalton
was about ten years old, about the age when he solved a
problem, discussed on a hay field among the farm people,
whether sixty yards square or sixty square yards are the
same. He at first considered them the same, but reflection
shewed him the difference. Dalton seldom failed for want
of perseverance ; he cheered his weary companion who was
soon outstripped, and who lived to look on the youth to
whom he supplied candles, with the reverence of those who
deeply conscious of ignorance imagine in knowledge the most
extravagant powers.

Dalton insisted on the importance of diligence, without
however considering that the work on which his fame was
founded was done comparatively in early life, and that his sub-
sequent unwearied application in no ways tended to elevate
his position in science. There is seldom much fame for the
idler, but we err greatly when we say a word to dishonour
the greatest of all gifts, which cannot be called by a less
name than Divine, the eye of genius.

On leaving the boyhood of Dalton we are not called to
look on it with surprise, we see in it indications of force, but
an equal display is sometimes apparent in less gifted men.
We can scarcely look with wonder at the elevation we have
seen him attain above his humble fellow-students and pupils.
Self-cultivation, too, is a problem now happily so often
solved by those who have nothing of true genius, that we

10 MEMOIR OF DR. DALTON, AND

can only look on his acquirements at that time as attain-
able with the greatest ease by one who had evidently that
gift in great force.

After spending about three years teaching in this school
he left Eaglesfield. About this time, getting on in life as
he thought, he first saw an umbrella in Cockermouth, and
bought one, thinking, as he afterwards expressed it, that he
was now becoming a gentleman. This happened in 1781,
when he became assistant to his cousin, George Bewley,
who kept a school in Kendal. His brother Jonathan had
been there as assistant for some time previously. In this
place twelve years of his life were spent, and here his true
education began. He had learned some Latin and Greek,
but neither now nor at any time of his life does he seem to
have attended much to literature or philology. He is said
to have had such an excellent memory that he repeated some
of Anacreon's Odes forty years after he had read them, but
a few of Anacreon's musical lines seem to be the common
property of school boys, who learn them easily from their
sound, whilst this knowledge gives no indication whatever
of proficiency in the language. A few old Greek books
were sold with the rest of his library, partly his own and
partly his brother's small stock, at Kendal. The Greek
dictionary, a Schrevelius, seems never to have been used.
Reading Greek books was no sport for a man who made
forty thousand meteorological observations.

In Kendal he became acquainted with Mr. Gough, a man
who although blind from infancy, was possessed of high
scientific attainments. The mutual assistance rendered is
best expressed in Dalton's own words. " For about eight
years during my residence in Kendal, we were intimately
acquainted; Mr. Gough was as much gratified with imparting
his stores of science, as I was in receiving them : my use to
him was chiefly in reading, writing, and making calculations
and diagrams ; and in participating with him in the pleasure

HISTORY OF THE ATOMIC THEORY. 1 1

resulting from successful investigations: but as Mr. Gough
was above receiving any pecuniary recompense, the balance
of advantage was greatly in my favour; and I am glad to
have this opportunity of acknowledging it. It was he who
first set the example of keeping a meteorological journal at
Kendal." Meteor. Observ. and Essays. Preface, 1834.

In an earlier edition Dalton had mentioned Gough as an
unknown friend; in the quotation given he does him that
justice which in his lifetime he was forbidden to do. Mr.
T. T. Wilkinson mentions that Dr. Whewell and several
other distinguished wranglers were prepared for their contests
by Mr. Gough. He himself wrote no separate work, but
many of his scientific memoirs have appeared. As a man he
seems to have inspired great respect in all who knew him,
and he must have been no common person of whom Words-
worth wrote ;

Metbinks I see him how his eyeballs roU'd
Beneath his ample brow, in darkness pained
But each instinct with spirit, and the frame
Of the whole countenance alive with thought,
Fancy, and understanding ; whilst the voice
Discoursed of natural or moral truth,
With eloquence and such authentic power,
That in his presence humbler knowledge stood
Abashed, and tender pity overawed.

The Excursion.

The poet, in a letter to Mr. Samuel Crompton, of Manches-
ter, writes, " Your conjecture concerning that passage is re-
markable ; Mr. Gough, of Kendal, whom I had the pleasure
of knowing, was the person from whom I drew the picture,
which was in no respect exaggerated. He was a most extra-
ordinary person, highly gifted, &c. The sadness which the
contemplation of blindness always produces, was in Mr.
Gough's case tempered by admiration and wonder in the
most affecting manner."

During the time that Dalton was enjoying the instruction
and advice, as well as the library and scientific apparatus of

12 MEMOIR OF DK. DALTON, AND

Mr. Gough, his cousin George Bewley gave up the school,
and the two brothers who had assisted him thus announced
their intention of continuing it.

"Jonathan & John Dalton respectfully inform their Friends,
and the Public in General, that they intend to continue the
school taught by George Bewley, where Youth will be care-
fully instructed in English, Latin, Greek, & French; also
Writing, Arithmetic, Merchant's Accounts, and the Mathe-
matics. The school to be opened on the 28th of March,
1785.

N.B. Youth boarded in the Masters' house on reasonable
terms."

Their sister Mary came to keep the house, and their father
and mother, then old people, frequently went to see them,
walking through on one day over " mountain and slack" a dis-
tance of 45 miles.*

George Bewley lent them some money, probably the house
or furniture answering to the sum, which was returned the
same year; the father lent them seven guineas, "to be paid
9 mo. 29th," which they paid only a week behind time. And
so they began life on a larger scale. They took care of their
money, balanced their books every month, and put down
every penny they spent. They had more than once to get a
guinea from Mr. Lickbarrow and two from Mr. Kendal, and
Mary had to give up her thirteen shillings and sixpence, and
got paid in portions, " Mary, in part, 0. 0. 6^-" Mr. Benson
too was paid all his money, and borrowings soon ceased.
The whole sum got the first year was about £107, but a
good deal of this had to be paid back, and indeed the average
of the school was about seventy pounds a year. This was
increased a few pounds by " drawing conditions," " collecting
rents," "making wills," and "searching registers," but the
amount gained by this means was seldom above five pounds a

* John Robinson, in Mr. Dickinson's Letter.

HISTORY OF THE ATOMIC THEORY.

13

year, although it rises to more than twice that sum in certain
years. We do not know if Dalton so employed himself, cer-
tainly however his brother did so.

A second circular issued by the Daltons in the following
year shews more fully the intentions of the school, and gives
us also an idea of the enlarged views of education which
Dalton took. *

Kendal, July 5th, 1786.
"Jonathan & John Dalton take this method of returning
their acknowledgments to their friends and the public for the
encouragement they have received since their opening school;
and from their care and assiduity in the management of it
manifested in the improvement of the Youth under their care,
are induced to hope for a continuation of their favours. They
continue to teach on reasonable terms English, Latin, Greek,
and French ;

Also,
Mensuration, Projections,

Surveying, Dialling,

Gauging, Optics,

Algebra, Mechanics,

Fluxions, Pneumatics,

Conic Sections, Hydrostatics,
Astronomy, Hydraulics, &c.

N.B. Persons desirous of being instructed in the use of
the globes, &c., will be waited upon any time out of school
hours. The Public may also be informed, that they could
conveniently teach a considerable number more than at pre-
sent. Those who send their children may depend upon their
being carefully instructed."

Writing,

Arithmetic,

Merchant's Accounts,

Geometry,

Trigonometry,

Navigation,

Geography,

To his usual instruction in school he added lectures. It is
certainly interesting to look over the syllabus published. We
see him as an ardent young man, filled with ideas from every
science, eager to tell them to others. We must remember

1 4 MEMOIR OF DR. DALTON, AND

that he is a man of simple mind, who had never seen a large
city, to whom the parade of the world and the unfortunate
pride of successful science was known only from books, and
we need not wonder that he expected on announcing the
truths he had learned to an ignorant rural population, a
crowd eager to hear them. Independent investigation had
not yet contracted his field of interest, so to speak, for we
find this effect produced of necessity in the mind which has
for a long time travelled alone over an unmapped district.
He is now 21 years of age, and gives the following pro-
gramme of lectures.

Oct. 26th, 1787.

" Twelve lectures on Natural Philosophy to be read at the
school (if a sufficient number of subscribers are procured) by
John Dalton. To begin on Tuesday evening the 13th Nov'^-
next, at 6 o'cl., and to continue every Tuesday and Thursday
at the same hour till compleated.

Subscribers to the whole ^ a guinea; or one shilling for
single nights.

N.B. Subscribers to the whole course will have the liberty
of requiring further explanation of subjects that may not be
sufficiently discussed or clearly perceived when under imme-
diate consideration; also of proposing doubts, objections, etc.;
all which will be illustrated and obviated at suitable times to
be mentioned at the commencement.

A Syllabus of the Lectures.
First & Second. Mechanics.

Introduction. Rules of Philosophizing on Matter and its
Properties with the diiferent opinions of the most famous
Philosophers on this head.

The laws of motion. Mechanic powers. Vibration of
pendulums.

Third, Fourth, & Fifth. Optics.

Preliminary discourse. Of the nature and properties of
light. Of simple vision. Doctrine of colours. Of reflected

HISTORY OF THE ATOMIC THEORY. 15

vision. Of mirrors and imaii^es reflected from them. Of re-
fracted vision, with the nature of lenses and images exhibited
thereby. Of burning glasses. Description of the eye.
Manner of vision. Of long and short sighted eyes. Of
spectacles, telescopes, & microscopes. Of the rainbow.
Sixth & Seventh. Pneumatics.

Of the atmosphere. The elasticity of the air. Descrip-
tion of the air pump. The spring and weight of the air
proved by a great variety of experiments on the air pump.
Of respiration. Of sound. Of winds. Of the blueness of
the sky. Of twilight.

Eighth, Ninth, & Tenth. Astronomy.

Introduction. Of the solar system. Of the figures, mag-
nitudes, distances, motion, &c. of the sun, planets, and
comets. Of the progressive motion of light. Of the fixed
stars and their phenomena. Of the lunar planets. Of
eclipses, tides, &c.

Eleventh & Twelfth. Use of the Globes.

Figure of the Earth. Description of the globes. Various
problems performed thereon, amongst which are, an explana-
tion of the phenomena of the harvest-moon and the variations
of the seasons. Conclusion.

* Ex rerum causis supremam noscere causam.' "

Miss Johns, whose diary will be spoken of below, tells us
that this very syllabus and one for 1792 came accidentally in
his way in after life when he was looking over some old
letters, having been detained in the house by a cold. He
burst out into a loud laugh.

The accounts given of the Daltons as teachers lead us to
believe them to have kept up the old system of great stern-
ness and formality, although John's character seems to have
been the milder of the two. Even during school hours he
was much occupied with mathematics and making calcula-
tions at all spare moments on bits of paper that came in

16 MEMOIR OF DR. DALTON, AND

his way. This sternness of manner never left him, although
his disposition was undoubtedly gentle. It may have arisen
from having been compelled so long to continue his pursuits
without the companionship of congenial minds, although
even that does not sufficiently explain the cause, as we
hear of others less befriended than Dalton whose disposition
has retained its vivacity. It is greatly to be regretted
that a journal containing all the minute particulars of his
life at this period should be entirely lost. Portions which
have been read to me by his friend Peter Clare intro-
duce us into his character in a very pleasing manner. We
find him cheerful and easy, fond of a little innocent sport, and
much attached to some games, but still so precise that every
one was rigidly recorded and the results of the play of each
party systematically compared. One evening at a house he
visited, the company spent their time making verses ; when
the last word of one verse was told, the next person in order
was expected to make a line to rhyme to it. It is curious
to observe that every couplet, as well as the author of each,
is carefully noted down in the diary. In this we have an
early illustration of the great order that was a prominent
point to be remembered in judging of his intellectual cha-
racter. This does not deny the paradoxical addition of great
carelessness. It was at this time that he was more especially
a student of the Lady's Diary, and one of those who
solved its problems, obtaining on several occasions the
prize. Even at Eaglesfield, however, he was employed,
although not with equal success, in the same manner, as Mr.
Dickinson says, " When I was a boy I saw John Dalton at
my cousin William Alderson's house, in Eaglesfield; they
talked of days when they were lads together, sitting over the
fire till midnight poring over the Lady's Diary. John never
giving sleep to his eyelids until he had found out the riddle of
some prize enigma or some mathematical question."

We find him at this time making his own barometers and

HISTORY OF THE ATOMIC THEORY, 17

thermometers, making experiments on hygrometers of whip
cord, sending specimens of butterflies to Mr. Crosthwaite's
museum in Keswick, and afterwards engaging for a very
small sum to send him dried specimens of plants. Mr.
T. P. Heywood, of the Isle of Man, has in his possession
eleven volumes of his Hortus Siccus, The first is a thick
volume, containing the general title page, Hortus Siccus
sen Plantaram diversarum in Agris Kendal vicinis sponte
nascentium Specitnina, Opere et Studio Johannis Dalton
collecta, et Secundum classes et ordines disposita, 1790."
The other volumes are thin. They are not preserved with
the greatest care which collectors are capable of, but they are
a proof of great industry and of considerable attainment, even
in a branch of science which he did not profess. He supplied
Mr. Crosthwaite with a barometer and thermometer, although
not knowing how to make them. He nevertheless begins and
learns their faults by experience. A letter given by Dr. Henry
shews us how his knowledge stood at this time, and how also
he was in the habit of acquiring it. Speaking of the mercury
in the barometer, he says, " I intend to renew mine as soon
as convenient ; if thou do the same, be careful in undoing it ;
and attend to the cautions I give. Be sure to rub the inside
of the tube well with warm dry cotton or wool, and have
the mercury when poured in at least milk warm, for moisture
is above all things else to be avoided, as it depresses the
mercury far more than a particle of air does ; mine is, as I
have said, at least xVth of an inch too low, and yet it is ^clear
of air, and to all appearance dry ; but I doubt not but at-
tending to these precautions, which I knew nothing of when
it was filled, will raise it up to its proper height."

At this time he felt uneasy, the sphere of his simple school
was too small, his impatience took the form of variety in his
pursuits, and he wandered over nearly every branch of
science. He seems now, although at a later time than
generally happens to young men, to have been "yearning
D

18 MEMOIR OF DR. DALTON, AND

for that large" existence which he knew to be somehow
attainable. He thought of a profession. His uncle Thomas
Greenup, the barrister, thought that it was entirely out of
the reach of a person in Dalton's circumstances to be a bar-
rister or a physician, and recommended rather as less difficult,
but still much above him, that of an attorney or apothecary.
It was at this time that he began to make medical experi-
ments, wishing to ascertain the loss from the human body by
insensible perspiration, a sufficient proof that however much he
might have advanced the knowledge of that profession, he was
too much an experimenter and solitary thinker to have been
pleased with the active life of some of our medical men. The
discouragement received from his friends seems to have pre-
vented all exertion in the new direction he had contemplated,
and he remained three years longer or until 1793 in Kendal,
when Dr. Barnes asked Mr. Gough for a suitable person to
teach mathematics in the New College of Manchester. This
college had arisen out of the Warrington academy, where
Priestley had taught, as well as Dr. Aikin, Dr. Enfield,
Reinhold Forster, and Gilbert Wakefield. At that time the
college was in the present " College-buildings," in Mosley-
street. He lived in the establishment, and remained tutor of
mathematics and natural philosophy for six years. Dr.
Barnes was the principal. This college is now transferred
to Gordon-square, London. Whilst here we find from
papers lent me by Mr. Woolley, that in 1794 he had twenty-
four pupils for mathematics, mechanics, geometry, algebra,
book-keeping, natural philosophy, and chemistry. He used
Lavoisier's Elements of Chemistry and Chaptal's amongst
others. In 1799 there were twenty-two students. Although
Manchester is now multiplied by four, it cannot shew the
same number, and I fear that the love of external things has
overpowered the love of science.

As soon as he gave up the intention of studying for a pro-
fession, he seems to have decided at once on a regular course

HISTORY OF THE ATOMIC THEORY. IQ

of investigation and in the interval from that time to 1793,
when he went to Manchester, produced his first work properly
so called, his " Meteorological Observations and Essays ;" they
were not, however, published until he had taken up his
position at the college.

This book contains an extensive series of observations on
old and new subjects, comprising ideas sometimes new, some-
times old, and at other times modifications oFthe old. He
enters into the discussion of the cause of the rise and fall of
the barometer, which he decides to be the existence of the
vapour of water in the air. Also he discusses the state of
water in the atmosphere, shewing it to be an elastic vapour
existing like any other gas not in chemical combination.
Then he treats of evaporation from the earth's surface, clouds
and rain, and allied phenomena, bringing, as Professor Sedgwick
says, "the elements themselves under his own intellectual
domination." The extent and variety of these inquiries prove
the earnestness with which he studied in his almost solitude
in Cumberland. The work seems to have been at first
intended as a popular treatise on meteorology. It begins
with a description of the barometer, then come the thermo-
meter, hygrometer, and rain gauges; connected with these
are tables of observations made at Kendal and Keswick.
There seems to be a looseness of description in the first part
of the volume, which would seem to imply that the matter
was easily understood, and the readers could make out the
particulars for themselves. As he proceeds, however, he
seems to feel that he has a harder task to perform, and
speaks rather to scientific than to popular hearers, whilst we
gradually become aware that he is a close and precise rea-
soner. His style is very simple; he goes directly to his
point ; all inessential parts are left out. He seems to move
forward with a heavy dogged tread, never turning his head
aside, but as any style may become a fault if too far carried
out, we find that in his there are left out many things that

20 MEMOIR OF DR. DALTON, AND

are certainly needful as accessory or confirmatory, leaving"
what to the eyes of many is a want of finish, so that others
have been needed to complete what was in reality suffi-
ciently complete had it been laid out entire as it existed in
his own mind.

As an example of his style, at p. 97, we find
"It appears from the observations (see table p. 15) that
the mean state of the barometer is rather lower than higher
in winter than in summer, though a stratum of air on the
earth's surface always weighs more in the former season than
in the latter; from which facts we must unavoidably infer
that the height of the atmosphere, or at least of the gross
parts of it, is less in winter than in summer, conformable to
the table p. 80. There are more reasons than one to con-
clude that the annual variation in the height of the atmos-
phere, over the temperate and frigid zones, is gradual, and
depends in a great measure on the mean temperature at the
earth's surface below, for clouds are never observed to be
above four or five miles high, on which account the clear air
above can receive little or no heat, but from the subjacent
regions of the atmosphere, which we know are influenced by
the mean temperature at the earth's surface; also, in this
respect, the change of temperature in the upper parts of the
atmosphere must in some degree be conformable to that of
the earth below, which we find by experience increases and
decreases gradually each year, at any moderate depth, ac-
cording to the temperature of the seasons.

" Now with respect to the fluctuations of the barometer,
which are sometimes very great in twenty-four hours, and
often from one extreme to the other in a week or ten days, it
must be concluded, either that the height of the atmosphere
over any country varies according to the barometer, or other-
wise that the height is little affected therewith, and that
the whole or greatest part of the variation is occasioned by a
change in the density of the lower regions of the air. It is

HISTORY OF TUE ATOMIC THEORY. 2 1

very improbable that the height of the atmosphere should be
subject to such fluctuations, or that it should be regulated in
any other manner than by the weekly or monthly mean tem-
perature of the lower regions; because the mean weight of the
air is so nearly the same in all the seasons of the year, which
could not be if the atmosphere was as high and dense above
the summits of the mountains in winter, as it is in summer.
However, the decision of this question need not rest on pro-
bability; there are facts which sufficiently prove, that the
fluctuation of density in the lower regions has the chief effect
on the barometer, and that the higher regions are not subject
to proportionable mutations in density. In the Memoirs of the
Royal Academy at Paris, for 1709, there is a comparison of
observations upon the barometer, at different places, and
amongst others, at Zurich, in Switzerland, in lat. 47° N.,
and at Marseilles, in France, lat. 43° 15^ N. ; the former
place is more than 400 yards above the level of the sea; it
was found that the annual range of the barometer was the
same at each place, viz., about 10 lines; whilst at Genoa, in
latitude 44° 25' N., the annual range was 12 lines, or 1 inch;
and at Paris, latitude 48° 50' N., it was about I inch 4 lines.
In the same memoir it is related that F, Laval made obser-
vations, for ten days together, upon the top of St. Pilon, a
mountain near Marseilles, which was 960 yards high, and
found that when the barometer varie<l 2 j lines at Marseilles,
it varied but 1 } upon St. Pilon. Now had it been a law,
that the whole atmosphere rises and falls with the barometer,
the fluctuations in any elevated barometer would be to those
of another barometer below it, nearly as the absolute heights
of the mercurial columns in each, which in these instances
were far from being so. Hence then it may be inferred, that
the fluctuations of the barometer are occasioned chiefly by a
variation in the density of the lower regions of the air, and
not by an alternate elevation and depression of the whole
superincumbent atmosphere. How we conceive this flue-

22 MEMOIR OF DR. DALTON, AND

tuation in the density of the air to be effected, and in what
manner the preceding general facts relative to the variation
of the barometer may be accounted for, is what we shall now
attempt to explain." This is referred to the varying amount
of vapour.

In section 5, " observations on the height of clouds," there
is given the summary of 5381 observations, made by Mr. Cros-
thwaite, an evidence of the intellectual diligence to be found
at the lakes even before they became the haunt of poets.

At p. 127 he gives a table of the temperature of water
made to boil at different atmospheric pressures, bearing on the
fact, which he is there explaining, that " aqueous vapour
always exists as a fluid sui generis diffused amongst the rest of
the aerial fluids;" and at p. 129, "that it may be determined a
priori what weight of vapour a given bulk of dry air will admit
of, for any temperature, provided the spec. grav. of the vapour
be given." These conclusions appear more fully in a note* to
a paper read in 1797, after having made confirmatory experi-
ments. This must be taken as an elucidation of a subject
which afforded much discussion at that period. We know
that Saussure and others knew well that moisture existed in
the air at very low temperatures, and there was a variety of
opinions as to the state in which it existed. Many writers of
the period believed, that because warm air was sensibly drier,
it contained less moisture than cold air; all these points
Dalton has elucidated and spoken on with decision.

In the third and sixth essays, the precise point where the
burden of his argument is contained is difficult to find, the
reasoning being a constant process to prove what it is supposed
we knew beforehand to be the result. In the appendix, he says
more pithily, p. 188, " I am confirmed in the opinion that the
vapour of water, and probably of most other liquids, exists
at all times in the atmosphere, and is capable of bearing any
known degree of cold without a total condensation, and that

* Memoirs of the Manchester Philosophical Society. Vol. V., p. 35 1.

HISTORY OF THE ATOMIC THEORY. 23

the vapour so existing is one and the same thing with steam^
a vapour of the temperature of 2X2° or upwards. The idea,
therefore, that vapour cannot exist in the open atmosphere
under the temperature of 212°, unless chemically combined
therewith, I consider as erroneous ; it has taken its rise from a
supposition, that air pressing upon vapour condenses the
vapour equally with vapour pressing upon vapour, a supposi-
tion we have no right to assume, and which I apprehend will
plainly appear to be contradictory to reason and unwarranted
by facts; for, when a particle of vapour exists between two
particles of air, let their equal and opposite pressures upon it
be what they may, they cannot bring it nearer to another
particle of vapour, without which no condensation of vapour
can take place, all other circumstances being the same; and
it has never been proved that the vapour in a receiver from
which the air has been exhausted, is precipitated upon the
admission of perfectly dry air. Hence, then, we ought to
conclude, till the contrary can be proved, that the condensa-
tion of vapour exposed to the common air does not in any
manner depend upon the pressure of the air"

At p. 1 35, after contending for the theory that the vapour
of water is mixed with the air and not combined, he explains
how it is precipitated by cold and taken up by heat, and how
it is that clouds consisting of light diops do not fall so readily
as clouds with heavy drops, as the resistance of the drops is
as the square of the diameter, in which his mathematical
knowledge helps his meteorology. This was suggested by
Mr. Gough.

There is in these Essays, and everywhere in Dal ton's
writings, a great rapidity of reasoning, a direct passage from
premise to conclusion without fear, as if more than usually
persuaded that true reason could not misguide him, so that he
is utterly regardless of consequences.

At p. IG8 we find a fair example of his mode of reasoning,
and one also of his daring theories.

24 MEMOIR OF DR. DALTON, AND

" The light of the aurora has been accounted for on three
or more different suppositions : — 1. It has been supposed to
be a flame arising from a chymical effervescence of com-
bustible exhalations from the earth. 2. It has been supposed
to be inflammable air, fired by electricity. 3. It has been
supposed electric light itself."

" The first of these suppositions I pass by as utterly
inadequate to account for the phenomena. The second is
pressed with a great difficulty how to account for the existence
oi strata of inflammable air in the atmosphere, since it ap-
pears that the different elastic fluids intimately mix with each
other; and even admitting the existence of these strata^ it seems
unnecessary to introduce them in the case, because w^e know
that discharges of the electric fluid in the atmosphere do
exhibit light, from the phenomenon of lightning. From these
and other reasons, some of which shall be mentioned hereafter,
I consider it almost beyond doubt that the light of the aurora
borealis, as well as that of falling stars and the larger meteors,
is electric light solely, and that there is nothing of combustion
in any of these phenomena. Air, and all elastic fluids, are
reckoned amongst the non-conductors of electricity. There
seems, however, a difference amongst them in this respect :
dry air is known to conduct worse than moist air, or air
saturated with vapour. Thunder usually takes place in sum-
mer, and at such times as the air is highly charged with
vapour ; when it happens in winter, the barometer is low, and
consequently, according to our theory of the variation of the
barometer, there is then much vapourized air ; from all which
it seems probable, that air highly vapourized becomes an
imperfect conductor, and, of course, a discharge made along a
stratum of it will exhibit light, which I suppose to be the
general cause of thunder and lightning."

" Now, from the conclusions in the preceding sections, we are
under the necessity of considering the beams of the aurora
borealis of a ferruginous nature, because nothing else is

HISTORY OF THE ATOMIC THEOET. 25

known to be magnetic, and consequently, that there exists in
the higher regions of the atmosphere an elastic fluid partaking
of the properties of iron, or rather of magnetic steel, and
that this fluid, doubtless from its magnetic property, assumes
the form of cylindric beams. It should seem, too, that the
rainbow-like arches are a sort of rings of the same fluid,
which encompass the earth's northern magnetic pole, like as
the parallels of latitude do the other poles ; and that the beams
are arrayed in equidistant rows round the same pole. ♦ * •
Things being thus stated, I moreover suppose that this
elastic fluid of magnetic matter is, like vapourized air, an
imperfect conductor of electricity; and that when the equi-
librium of electricity in the higher regions of the atmosphere
is disturbed, I conceive that it takes these beams and rings as
conductors, and runs along from one quarter of the heavens
to another, exhibiting all the phenomena of the aurora
borealisJ* *

In the edition of 1834 he still adheres to the same theory ;
some will look on it as absurd ; it is certainly the result of
great daring, or in other words, it may be viewed as the rea-
soning of a man who has exhausted all his knowledge in
finding a cause, feels certain that there is one, and decides
upon that which is most conformable to his knowledge, with-
out waiting for a wider view, or for a time when something
perfectly nevv might entirely change the scene.

This essay on the aurora he considered as of great import-
ance. He begins with these words ; " As this essay contains an
original discovery which seems to open a new field of inquiry
in philosophy, or rather, perhaps, to extend the bounds of one
that has been as yet but just opened ; it may not, perhaps, be
unacceptable to many readers to state briefly the train of
circumstances which led the author to the important con-
clusions contained in the following pages." And yet we take
up treatises on the aurora, and do not even find Dalton's name

♦ The pages refer to the new edition.
E

26 MEMOIR OF DR. DALTON, AND

mentioned. Wargentin, Halley, and Celsius had all observed
the action of the aurora on the magnetic needle. Dr. Halley
had supposed it to be caused by magnetism. Dalton went
more fully into the subject than his predecessors, without,
however, taking all difficulty from it. In this treatise we see
an instance of the pertinacity with which he held ideas which
he had formed. But we find him altering his opinion on the
height of the aurora; his observations led him to believe
the height to be about 150 miles; afterwards he considered
it to be about 100. Numerous as have been the attempts
to ascertain the height, the differences ranging from feet to
thousands of miles, Dalton still, in 1834, severely criticised
all the observations which differed greatly from his early
results. To this treatise on meteorology he added little,
although a new edition appeared after forty years. He
then says, that it is printed verbatim (adding only a small
appendix), "as I apprehend it contains the germ of most of
the ideas which I have since expanded more at large in dif-
ferent essays, and which have been considered as discoveries
of some importance." But he says also, that " the subject
here treated of appeared to the author to be very imperfectly
appreciated, or little understood, by some of the modern
writers on meteorology," and it is probably true that the
facts and theories he advanced had, in some or many in-
stances, been worked out by others with little aid from his
book, because, although occasionally quoted, it was really
very little known. This arose from a peculiarity in his mode
of publishing it. It was like all his books printed for him-
self, and was never allowed to make its due way in an inde-
pendent manner among the booksellers, nor had the essays
the advantage of being read to a society, or given out by
any journal.

HISTOKY OF THE ATOMIC THEORY. 27

CHAPTER II.

HIS EPOCH OF GREATEST FERTILITY.

The work on meteorology was published in September, 1793.
Dalton had come to Manchester in the spring of that year.
He was now twenty-seven years of age. The removal to an
active town seems to have satisfied his cravings for a larger
sphere of labour which were forcing him from his attachment
to his neighbourhood. He was self-taught, a raw countryman,
in many respects rather rough in his acquired habits, although
of a naturally gentle disposition. Such a distance from active
life would have made many men idle, such a sudden entrance
into it has often the same effect on others. Neither seemed
to affect him, there was little change of habit, he was still in
the streets of Manchester as on the hills of Cumberland,
the active observer and thinker. On October 3rd, 1794,
he first appears as a member of the Literary and Philoso-
phical Society of Manchester, having been proposed by
Thomas Henry, Dr. Percival, and Robert Owen, the veteran
enthusiast who would willingly compel all mankind to be
reformed by his simple formula. On the 3 1st, he read his
first paper to the society, an event to him of great import-
ance, greatly influencing all his future life, as he soon after
became the representative of that body, continuing so for
the remainder of his life.

This paper was entitled " Extraordinary Facts relating to
the Vision of Colours."* He says there, p. 30,

" It may be proper to observe, that I am shortsighted.
Concave glasses of about five inches focus suit me best. I
can see distinctly at a proper distance; and am seldom hurt by
too much or too little light; nor yet with long application."

• Memoirs of the Philosophical Society of Manchester. Vol. V., p 28.

28 MEMOIR OF DR. DALTON, AND

" I found that persons in general distinguish six kinds of
colour in the solar image ; namely, red, orange, yellow,
green, blue, and purple. To me it is quite otherwise; I
see only two, or at most three, distinctions; these I should
call yellow and blue, or yellow, blue, and purple. * * * *
My yellow comprehends the red, orange, yellow, and green
of others, and my blue and purple coincide with theirs."

He sums up the peculiarities of the vision of himself and
others who have been found similarily affected thus; p. 40.

"1. In the solar spectrum three colours appear — yellow,
blue, and purple. The two former make a contrast ; the two
latter seem to differ more in degree than in kind.

2. Pink appears, by day light, to be sky-blue a little
faded; by candle light it assumes an orange or yellowish
appearance, which forms a strong contrast to blue.

3. Crimson appears a muddy blue by day ; and crimson
woollen yarn is much the same as dark blue.

4. Red and scarlet have a more vivid and flaming appear-
ance by candle light than by day light.

5. There is not much difference in colour between a stick
of red sealing wax and grass, by day.

6. Dark green woollen cloth seems a muddy red, much
darker than grass, and of a very different colour.

7. The colour of a florid complexion is dusky blue.

8. Coats, gowns, &c., appear to us frequently to be badly
matched with linings, when others say they are not. On the
other hand, we should match crimsons with claret or mud ;
pinks with light blues ; browns with reds ; and drabs with
greens.

9. In all points where we differ from other persons, the
difference is much less by candle light than by day light."

He found several persons having the same peculiarity of
vision, and says (p. 43i), " It appears, therefore, almost
beyond a doubt, that one of the humours of my eye, and of

HISTORY OF THE ATOMIC THEORY. 29

the eyes of my fellows, is a coloured medium, probably some
modification of blue."*

Although this paper was an observation on himself, it is in
reality a discovery ; the facts had not been arranged before
he arranged them, and found out other persons similarly
situated. A peculiar keenness of reasoning was needed to
find it out, as we must remember that with such persons
there is little community of feeling on colour, and scarcely a
mode of judging whether they see any colours exactly as the
normal eye does. It would probably explain many strange
occurrences if we were to consider that there are really per-
sons in the world who see all crimsons as " dark blue'* or
'* a muddy blue," and who would " match crimsons with
claret or mud ; pinks with light blues ; browns with reds ;
and drabs with greens ; " who see the healthful tints of a
florid complexion to be lik^ " dilute black ink on white
paper," or "a dull opake blackish blue, upon a white
ground." How many strange mistakes and visions might
be accounted for by this defect of sight. A fair face with
glowing veins would be lo Dal ton as a corrupting corpse.
But it may be said that custom would make all appear as
well to him as to others ; no, it cannot be so : a defect must
constantly carry with it the consequences of a defect, and in
this case the established difference which nature has made
between life and death, beauty and horror, was hidden from
the eye, and therefore to a great extent must have been
concealed from the intellect. To this cause partly we may
refer that want of fine sensibility to external things which
peculiarly marked his scientific as well as social life.

Dr. Whewell has called such persons idiopts, because their
vision is peculiar ; this is not sufficiently characteristic, and

• Mr. J. A. Ransome, who examined the eye after death, found nothing
whatever to account for the peculiarity of vision. Certainly colours appeared
as usual through it. He believed that the cause was a deficient sensorial or
receptive power.

30 MEMOIR OF DR. DALTON, AND

as has been remarked sounds badly, Sir John Hersehel having
changed it to Dichromic vision, believing that one of the
three colours is lost to the eye entirely. Such a vision there
seems to be, but this extent has not been observed in any
instances, by Dr. George Wilson, who thinks that there is
no colour quite lost, although the power of perceiving be
feeble, and he names it Chromato-Pseudopsis, or a false
vision of colours. This he has translated by Sir D. Brewster's
term, colour-blindness, which appears much too strong when
we consider that some colours are well seen, and others seen
in part. It seems, in fact, to be an imperfection in the power
of distinguishing colours, which may exist to any extent, either
very slightly, as is seen in e very-day life, where, for example,
among the many workpeople in a large mill, only a few
are found fit for arranging yarns with accuracy. A nice
perception of colour is there a*valuable gift, and is paid for
accordingly. Or it may occur decidedly defective, as with Dr.
Dalton and others. Dalton's brother had the same defect,
and one or two others in the neighbourhood of Eaglesfield,
of whom I have lately heard. It is probable that there are
many gradations, beginning with deficient colour sight and
ending in Dichromic, or perhaps Monochromic or Achromic
vision, or true colour blindness. Dr. Wilson well remarks,
that Daltonism, under which it has been known, is not a
proper name for the peculiarity, as it connects his name
with a defect. Indeed few eyes are found equal to Dalton's,
if we judge of them by their results. Dr. Wilson has made
the remarkable discovery that this defect may almost be
called common.

Dalton remained without giving anything to the public
until 1799. In the College his order showed itself in the
careful list of students and their lessons, still remaining.
Possibly his duties occupied too much of his time to allow
of experiment, but he comes out so suddenly after that as
physikist and chemist, that his time must have been spent

HISTORY OF THE ATOMIC THEORY. 31

in suitable studies. On March 1st, 1799, he read to the
Literary and Philosophical Society* " Experiments and
observations to determine whether the quantity of rain and
dew is equal to the quantity of water carried off by the
rivers and raised by evaporation; with an inquiry into the
origin of springs." In this he treats, —
"1. Of the quantity of rain and dew.

2. Of the quantity of water that flows into the sea.

3. Of the quantity of water raised by evaporation.

4. Of the origin of springs."

The first three are accompanied by experiments, but there
is a looseness in the calculations which renders the paper rather
like a sketch of the subject. He, however, collects a great
deal of information as to the annual fall of rain in various
places, and in a note explains clearly, as before alluded to, his
ideas as to the state of aqueous vapour in the air. The loose-
ness of expression is not at all times with him an indication of
want of decision, but his peculiar style of writing, as if every
one knew the subject, and were ready to draw out his reasoning
into all its details, as soon as expressed. His experiments,
begun with the hand, seem often finished with the head, so
rapidly are his conclusions come to, and the natural law estab-
lished in his mind. Even now we can add little to the relation
between evaporation, rain, and dew, and on the origin of
springs he is clear, quick, and decisive, saying that they come
from the rain. This subject had been much disputed ; filtra-
tion from the sea having been a favourite method of obtaining
the water, as well^s subterranean reservoirs like those of Father
Kircher, who shows them in engravings continually boiling
out from the centre of the earth. Dalton was not the first to
suggest the explanation, of course, but the subject was
sufficiently uncertain to call for elucidation. On April 12th,

* Memoirs of the Literary and Philosophical Society of Manchester. Vol.
v., p. 346.

32 MEMOIR OF DR. DALTON, ANI)

1799, he read a paper entitled " Experiments and observations
on the power of fluids to conduct heat, with reference to Count
Rumford's seventh essay on the same subject."*

He seems evidently to have made up his mind at once that
Count Rumford had drawn a wrong conclusion from his
premises, and we see in the reasoning much minute ingenuity
and acuteness. As an example of his mode of experimenting
and reasoning, the following may be given, p. 381.

" Exp. 3. Took an ale glass of a conical figure, 2J inches
in diameter, and 3 inches deep ; filled it with water that had
been standing in the room, and consequently of the temperature
of the air nearly. Put the bulb of a thermometer to the
bottom of the glass, the scale being out of the water ; then
having marked the temperature, I put the red-hot tip of a
poker half-an-inch deep into the water, holding it there steadily
about half-a-minute ; and as soon as it was withdrawn, I dipped
the bulb of a sensible thermometer about ^ inch, when it rose
in a few seconds to 180.°

Temperature.

Time. At Top. Middle. Bottom.

Before the poker was immersed ... ... 47^

— ... 180° ... — ... 47°

5min. ... 100° ... 60° ... 47^°

20 „ ... 70° ... 60° ... 4r

1 hour ... 55° ... — ... 52°"

After other experiments he says, p. 385, "We must con-
clude, therefore, that the quick circulation of heat in water
over a fire, &c., is owing principally to the internal motion
excited by an alteration of specific gravity; but not solely
to that cause, as Count Rumford has inferred."

Avery simple and ingenious experiment is related on the same
page. He mixed hot and cold water, stirred for half-a-minute,
and tried if the upper part became hotter than the lower, it

* Same vol., p. M73.

HISTORY OF THE ATOMIC THEORY. 33

did not do so, on which he says, " If the particles of water
during the agitation had not actually communicated their
heat, the hot ones ought to have risen to the top, and the
cold ones subsided, so as to have made a material difference
in the temperature." This shows, that even at that period
he was accustomed to think habitually of matter as decidedly
atomic in its constitution.

On the theoretical conclusion to be drawn here, we find his
genius taking the lead ; he is accurate in spite of the rudeness
of his experiments. He concludes that water conducts heat
a little, and that the expansion of water is the same both above
and below the point of maximum density. But when he comes
to determine the precise place at which that point is found, as
it is a matter of experiment, and cannot be got by the mind
only, he is at fault; in subsequent experiments learning to
become accurate.

He seems to have lowered the point to 36°, and after-
wards considered it 38°, the point now apparently fixed on
is 39°, or 39.101. (Playfair and Joule.) Dr. Hope's experi-
ments gave it as between 39^ and 40 degrees. In this
investigation Dalton's mind again analyses itself, dividing
to great clearness of conception on the one side, and
carelessness of minute observation on the other.

In 1830 on reading over some old letters which he was
arranging, he found one from Dr. Hope, saying, " notwith-
standing the caution you gave me, I venture to publish my
pamphlet on the contraction of water by heat,'* Dr. Dalton
said, "aye, he had the advantage of me there, but not so
much as it appeared at first sight."

In this paper he makes an observation on the power of
capillary tubes to prevent the freezing of water, a circum-
stance which has not been thoroughly inquired into, nor the
cause assigned its proper place.

In May, 1800, Dalton was elected secretary of the
Literary and Philosophical Society of Manchester, in the
F

34 MEMOIR OF DR. DALTON, AND

place of Dr. William Henry, and having as his colleague Dr.
Hull. This office he retained until the year 1608, when he
was made vice-president in the room of Dr. Roget, who then
lived in Manchester. Soon after, on June 27 th, he read to that
Society, *' Experiments and observations on the heat and cold
produced by the mechanical condensation and rarefaction of
air." * Here by well devised experiments he endeavoured
to shew what however had been before held by Lambert,
Saussure, and Pictet, " that the capacity of a vacuum for
heat is less than an equal volume of atmospheric air, and
that the denser air is, the less is its capacity for heat," indi-
cating a mode of ascertaining " the absolute capacity of a
vacuum for heat," and " likewise the capacity of the different
gases for heat by a method wholly new." An important
result of these experiments was, that the temperature of air
mechanically compressed to one-half its volume was raised
50°. This, although much underrated, was the first nume-
rical result of importance on this subject, p. 524.

In this paper we find that he had ascertained that gases
expand 1-lOth of their volume nearly for 50° of heat, or
nearly 1 -500th of their bulk, a subject which he treated of
at a later period.

Whilst engaged in teaching at the academy in Manchester,
his classes or scholars seem to have been as miscellaneous
as they had been at Kendal. We may infer this from the
appearance of an English grammar, the preface of which
is dated March 10th, 1801. He seems to have looked
on this as a recreation, but he never afterwards appears
to have had recourse to literature for amusement or for
variety. As he has never been looked on as a grammarian,
it may be of some interest to see what his views on such
points were.

He says, p. 8. " It may be taken as an axiom that all
time or duration in the strict sense of the terms, is either

• Mem., Vol. V., p. 516.

HMTORY OF THE ATOMIC THEORY. 35

past or future. But for the purposes of speech we must
have a present time of some duration, which must necessarily
be comprised of a portion of past and a portion of future,
having the present, now or instant, as a boundary between
them. Its length may be what we please to make it.

" Grammatically speaking therefore, there are three times,
present, past, and future ; though strictly and mathematically
speaking, we can admit only two, past and future. Moreover
we find it expedient in the course of conversation, not only to
mention actions as whole and entire, but also their commence-
ment, their being in a passing or middle state, and their
termination ; accordingly our language furnishes us with four
forms of speech for each of the times or tenses, which are
exemplified in their proper place, both for the active and
passive verb, with appropriate names to them."
His active verb is given thus : —
Indicative mood.

Present time.

I serve, &c.

Beginning present.

I am about to serve, &c.

Middle present.

I am serving, &c.

Ending present.

I have served or been serving, &c.

Past time,

I served, &c.

Beginning past.

I was about to serve, &c.

Middle past.

I was serving, &c.

Ending past.

I had served or been serving, &c.

Future or present time.

I shall, will, may, can or must serve, &c.

3G MEMOIR OF DR. DALTON, AND

Beginning Juture or present.

I shall, will, may, can or must be about to serve, &c.

Middle future or present.

I shall, will, may, can or must be serving, &c.

Ending future or present.

I shall, will, may, can, or must have served or have
been serving.
In grammar it is difficult to have absolutely new ideas, the
subject has been so belaboured, and at the same time it is
not easy to keep rigidly to any system proposed, so many of
the treatises have wanted clearness. We may see that in
that department Dalton was inclined to be an innovator,
although he has not the honor of being a discoverer, indeed
his mind was much too rigid to be inclined to yield to all
the flexions and variations of a subject so bordering on meta-
physics as grammar. Home Tooke is the writer which
he most admired on that subject, using sometimes his very
words, although not in all things following him. But
innovators are more dangerous in grammar, and are less
easily received, than in the physical sciences which have
'no ancestry.

Some years afterwards he went into the shop of the pub-
lisher of his grammar, and asked for a copy ; he was told they
had none, but insisting on it, a parcel of them was found in
some dusty corner, very few having ever been sold. Still he
assures us that a Sheffield man had published it some years
later as his own, with some additions.

In October of the same year he read a paper which occu-
pied three evenings of the Literary and Philosophical Society.
It is composed of four " Experimental essays on the consti-
tution of mixed gases ; on the force of steam or vapour from
water and other liquids in different temperatures, both in a
Torricellian vacuum and in air ; on evaporation ; and on the
expansion of gases by heat." (Mem. Vol. V., p. 535.)

HISTORY OF THE ATOMIC THEORY. 37

The four laws given by him are —

" 1. When two elastic fluids, denoted by A and J3, are
mixed together, there is no mutual repulsion amongst their
particles ; that is, the particles of A do not repel those of B,
as they do one another. Consequently, the pressure or
whole weight upon any one particle arises solely from those
of its own kind.

" 2. The force of steam from all liquids is the same, at equal
distances above or below the several temperatures at which
they boil in the open air ; and that force is the same under
any pressure of another elastic fluid as it is in vacuo. Thus
the force of aqueous vapour of 212° is equal to 30 inches of
mercury; at 30° below, or 182°, it is of half that force; and
at 40° above, or 252°, it is of double the force ; so likewise
the vapour from sulphuric ether, which boils at 102°, then
supporting 30 inches of mercury, at 30° below that tem-
perature it has half the force, and at 40° above it, double
the force; and so in other liquids. Moreover the force of
aqueous vapour of 60° is nearly equal to J inch of mercury,
when admitted into a Torricellian vacuum ; and water of the
same temperature, confined with perfectly dry air, increases
the elasticity to just the same amount.

" 3. The quantity of any liquid evaporated in the open air
is directly as the force of steam from such liquid at its tempe-
rature, all other circumstances being the same.

"4. All elastic fluids expand the same quantity by heat;
and this expansion is very nearly in the same equable way as
that of mercury ; at least from 32° to 212°. It seems probable
the expansion of each particle of the same fluid, or its sphere
of influence, is directly as the quantity of heat combined
with it ; and consequently the expansion of the fluid as the
cube of the temperature, reckoned from the point of total
privation."

The first law accounts for a diff'usion of gases to a great
extent, but not entirely. It would result from it, if not qua-

38 MEMOIR OF DR. DALTON, AND

lified, that there would be a diminishing quantity of oxygen,
which is the heaviest gas in the atmosphere, according as
the height increased. This was Dalton's opinion, but it has
not turned out to be the case. This law was much assailed,
and at the same time much misunderstood. The objection
that vapour did not rise so rapidly in air as in a vacuum
seemed to him a strong one, which he did not quite get over,
but considered it as presenting the same difficulty to all
theories of the solution of water in air.

The law was stated too broadly, it did not even allow room
for the impenetrability of matter to have its due place, and
many persons supposed it to mean that a space filled with one
gas, might be filled with an equal quantity of another.

He subsequently stated these two propositions in the
following form, which he published in the second edition of
his " New system of chemistry," when, after many years, he
reviewed himself and his reviewers, p. 191, Part I., 1842.

"1. The diffusion of gases through each other is effected
by means of the repulsion belonging to the homogeneous
particles; or to that principle which is always energetic to
produce the dilatation of the gas.

" 2. When any two or more mixed gases acquire an equi-
librium, the elastic energy of each against the surface of the
vessel or of any liquid, is precisely the same as if it were the
only gas present occupying the whole space, and all the rest
were withdrawn."

There is no doubt that the law had been hastily expressed :
explaining some points, it contradicted others. The pheno-
menon of the mixing of gases is easily explained, if we admit
the constant intestine motion of the particles to be a necessary
condition of the existence of a body in a gaseous state. (See
a paper " On the changes of temperature produced by the
rarefaction and condensation of air," by J. P. Joule. Phil.
Magaz,, May, 1845.)

The second essay is on the force of steam or vapour. He

HISTORY OF THE ATOMIC THEOKY. 39

gives a long table of the force of aqueous vapour at different
temperatures, from 40° to 325°. Between 32° and 312° the
numbers are given from experiment ; above and below these
limits the numbers are from calculation. These tables were
afterwards modified by himself, and others have also reduced
them to greater accuracy. He objects to the tables from
water and alcohol given by M. Betancourt in 1790, and to
that in the Encyclopaedia Britannica, because the authors
had assumed the force of that from water, at 32°, to be
nothing. This constituted one of the steps which the subject
made in its rather retarded progress.

He gives a series of experiments on the power of vapour
from liquids, supporting his conclusions by experiments on
ether, alcohol, water of ammonia, solution of muriate of lime,
mercury, and sulphuric acid, and says " That the variation of
the force of vapour from all liquids is the same for the same
variation of temperature, reckoning from vapour of any
given force; thus assuming a force equal to 30 inches of
mercury as the standard, it being the force of vapour from
any liquid boiling in the open air, we find aqueous vapour loses
half its force by a diminution of 30° of temperature; so
does the vapour of any other liquid lose half its force by
diminishing its temperature 30° below that in which it boils,
and the like for any other increment or decrement of heat."
p. 564.

When speaking of vapour of water in air, he says " the re-
sults of all agree in one general rule or principle, which is this ;
let 1 represent the space occupied by any kind of air of a
given temperature, and free from moisture ; p = the given
pressure upon it in inches of mercury; =/*=: the force of
vapour from any liquid in that temperature in vacuo ; then
the liquid being admitted to the air, an expansion ensues,
and the space occupied by the air becomes immediately and
in a short time = 1 + 7^5 or which is the same thing = -^ f /.
Thus in water for instance, let p = 30 inches/= 15 inches

40 MEMOIR OF DR. DALTON, AND

to the given temperature 180°. Then -—j- = lo^iy = 2
for the space; or the air becomes of twice the bulk."
p. 572. " In short, in all cases the vapour arises to a
certain force according to temperature, and the air adjusts
the equilibrium by expanding and contracting as may be
required."

" The notion of a chemical affinity subsisting between the
gases and vapours of different kinds cannot at all be reconciled
to these phenomena." p. 574.

This notion of chemical affinity holding the gases in
solution had begun to die out.

In essay third, " On evaporation" he concludes that the
quantity of any liquid evaporated in the open air is directly
as the force of steam from such liquid at its temperature, all
other circumstances being the same. He adds a *' table
shewing the force of vapour, and the full evaporating force
of every degree of temperature from 20° to 85°, expressed in
grains of water that would be raised per minute from a
vessel of six inches in diameter, supposing there were no
vapour already in the atmosphere." p. 585. He obtained the
evaporation from a surface when the air was still and when
in motion. He adds also rules to find the amount of water
that can be evaporated from a given surface when the
temperature of the air is given, and the condensing point,
and to find the force of the aqueous vapour.

The fourth essay on the expansion of elastic fluids by heat
proves the law already stated.

The position of the question when he took up the subject
may best be explained by himself, he says, p. 595, " The
principal occasion of this essay is another on the same subject
by Messrs. de Morveau and du Vernois, in the first vol. of
the Annalesde Chimie. It appearing to them that the results
of the experiments of De Luc, Col. Roy, de Saussure,
Priestley, Vandermonde, Berthollet, and Monge, did not
sufficiently accord with each other ; and that it would be of

HISTORY OF THE ATOMIC THEORY. 41

importance to determine not only the whole expansion of
each gas from two distant points, such as the freezing and
boiling, but likewise whether that expansion be uniform in
every part of the scale, they instituted a set of experiments
expressly for those purposes. The result of which was;
that betwixt the temperatures of 32° and 212°, the whole ex-
pansion of one gas diifers much from that of another, it being
in one instance about 4-lOths of the original, and in others,
more than twelve times that expansion ; and that the expansion
is much more for a given number of degrees in the higher
than in the lower part of the scale. These conclusions were
so extremely discordant with and even contradictory to those
of others, that I could not but suspect some great fallacy in
them, and found it in reality to be the fact ; I have no doubt
it arose from the want of due care to keep the apparatus and
materials free from moisture."

After giving his experiments on air, hydrogen, oxygen,
carbonic and nitrous gas, in which " the small differences
never exceeded six or eight parts, on the whole 345," he
adds, " Upon the whole, therefore, I see no sufficient
reason why we may not conclude that all elastic fluids under
the same pressure expand equally by heat, and that for any
given expansion of mercury, the corresponding expansion of
air is proportionally something less, the higher the tempe-
rature."

'' This remarkable fact that all elastic fluids expand the
same quantity in the same circumstances, plainly shews that
the expansion depends solely upon heat; whereas the expan-
sion in solid and liquid bodies seems to depend on an adjust-
ment of the two opposite forces of heat and chemical affinity,
the one a constant force in the same temperature, the other
a variable one, according to the nature of the body ; hence the
unequal expansion of such bodies. It seems, therefore, that
general laws respecting the absolute quantity and the nature
of heat, are more likely to be derived from elastic fluids than
0

42 MEMOIR OF DK. DALTON, AND

from other substances." There is an admirable clear-sighted-
ness in his short and rapid conclusions. The same law of
equal expansion of gases was published six months later by
Gay Lussac, and is often called by his name. Dr. Ure says
the experiments were made by Gay Lussac with much more
care and exactness, but the newest results obtained by Reg-
nault by no means speak so in favour of Gay Lussac. The
difference between his results and Dalton's were only trifling.
Gay Lussac gave the expansion per degree at 480, Dal ton
483, Regnault 491. In this country we have generally used
Gay Lussac's for no sufficient reason. On the Continent
Dalton has almost been entirely deprived of his merit, and is
not even mentioned in connection with it in many French and
German works : but such circumstances are unfortunately of
constant occurrence. It is difficult to find the reason of this,
but it happens so often that our countrymen are quite omitted
in their works, that it must in a great measure arise from
their neglect of our literature. This certainly must be the
cause, as we find that both French and Germans of high name
can treat latent heat without even mentioning the name of
Black, whose claims are not even disputed ; this last occurs
even with the very systematic Gmelin. We can readily
imagine how some of the other papers of Dalton have been
overlooked as merely additions to a subject, whereas he who
gives the polish and establishes the law has been allowed the
entire credit. They were certainly put within the reach of
inquirists, as he says in a letter quoted in Dr. Henry's life of
him, p. 50. " My lately published essays on gases, &c., toge-
ther with the more recent ones read at our society, and of which
I gave the result in my late lectures, have drawn the attention
of most of the philosophers of Europe. They are busy with
them at London, Edinburgh, Paris, and in various parts of
Germany, some maintaining one side and some another. The
truth will surely out at last." Although not alluding specialljn

HISTORY OF THE ATOMIC THEORY. 43

to the last mentioned memoir, this letter alludes to his inves-
tigations generally, which had been everywhere discussed.

On November 12th, 1802, he read to the Literary and
Philosophical Society an " Experimental inquiry into the
proportion of the several gases or elastic fluids constituting
the atmosphere."*

These he made by weight, p. 257.

Azotic gas 75.55

Oxygenous gas 23.32

Aqueous vapour 1.03

Carbonic acid gas 10

100.00

In another place we find, by bulk 79 azote.

21 oxygen.

In describing his Eudiometric process he has a few observa-
tions of great importance, indications of the direction in which
he was moving, but given in such a way as to lead us to the con-
clusion that he had not yet seen their value; teaching us
also that an idea of definite proportions may exist without
any distinct nature of the completeness of the law of equiva-
lents as it stands. At page 249 he says, —

"2. If 100 measures of common air be put to 36 of pure
nitrous gas in a tube 3-lOths of an inch wide and 5 inches
long, after a few minutes the whole will be reduced to 79
or 80 measures, and exhibit no signs of either oxygenous or
nitrous gas.

"3. If 100 measures of common air be admitted to 72 of
nitrous gas in a wide vessel over water, such as to form a thin
stratum of air, and an immediate momentary agitation be used,
there will, as before, be found 79 or 80 measures of pure azotic
gas for a residuum.

" 4. If in the last experiment, less than 72 measures of
nitrous gas be used, there will be a residuum containing oxy-

* Ist vol. of Memoirs, new series, p. 244.

44 MEMOIR OF DR. DALTON, AND

genous gas ; if more, then some residuary nitrous gas will be
found.

" These facts clearly point out the theory of the process :
the elements of oxygen may combine with a certain portion
of nitrous gas, or with twice that portion, but with no inter-
mediate quantity. In the former case nitric acid is the
result, in the latter nitrous acid ; but as both these may be
formed at the same time, one part of the oxygen going to one
of nitrous gas and another to two, the quantity of nitrous gas
absorbed should be variable; from 36 to 72 per cent, for com-
mon air. This is the principal cause of that diversity which
has so much appeared in the results of chemists on this subject."

In the paper on the expansion of elastic fluids, he had
already, in a plate, shown that he was accustomed to view
gases as composed of definite particles, having drawn each
with a different form.

Immediately after this, January 28th, 1803, he read, an
inquiry " On the tendency of elastic fluids to diff*usion through
each other."* This subject was first begun by Priestley.
The memoir which he has written on the transmission of
gases through porous vessels, entitled " Experiments re-
lating to the seeming conversion of water into air," is
certainly one of the most beautiful specimens of investiga-
tion that can anywhere be found. He there establishes the
fact, that through porous vessels, gases pass one way, vapour
of water and other liquids another ; and observed, that the
mercury in one experiment had risen 3 J inches above the
level on the outside. He afterwards found that what could
take place with " air and water, will be done with any two
kinds of airs."

He failed, however, to make the next step, having said
that it is probable " that if two kinds of air of very different
specific gravities, were put into the same vessel with very
great care, they might continue separate," although his

• Memoirs, Vol. 1., New Series, p. y59.

HI8T0BY OF THE ATOMIC THEORY. 45

own experiments justified a different opinion. Dalton took
the subject up at this stage, and says the result "estab-
lishes this remarkable fact, that a lighter elastic fluid cannot
rest upon a heavier, as is the case with liquids ; but they are
constantly active in diffusing themselves through each other
until an equal equilibrium is effected ; and that without any
regard to their specific gravity, except so far as it accelerates
or retards the effect according to circumstances." *

** The only apparatus found necessary, was a few phials
and tubes with perforated corks ; the tube mostly used was
one 1 0 inches long, and of l-20th inch bore ; in some cases a
tube of 30 inches in length, and l-3rd inch bore was used;
the phials held the gases that were subjects of experiment,
and the tube formed the connection." p. 261. This tube
was often a piece of tobacco pipe.

He believes that this proves his theory of elastic fluids to be
correct, that gases are as a vacuum to each other, and it no
doubt does favour it, especially as he added that they might
be obstructed as a stream of water by a stony bed. Still this
very explanation takes away much of the original meaning,
and any of his difficulties as to the mutual action of gases
must be cleared by further experiments, as has been the case
with the laws of diffusion which have already been shewn to us
by Professor Graham. There is no doubt that Dalton's
expression is an useful attempt to grasp a great difficulty, not
yet grasped, we shall see him returning to it again in the
next paper.

On October 2 1st, 1803, he read to the Literary and
Philosophical Society, another investigation " On the ab-
sorption of gases by water and other liquids." p. 27 1 ., Vol. I.,
New Series.

In this he says, 2. " If a quantity of water freed from
air be agitated in any kind of gas not chemically uniting
with water, it will absorb its bulk of the gas, or otherwise a

• Page 260, Vol. I., New Series.

46 MEMOIR OF DR. DALTON, AND

part of it, equal to some one of the following fractions,
namely, l-8th, l-27th, l-64th, l-125th, these being the
cubes of the reciprocals of the natural numbers 1, 2, 3, &c.;"
This has not found general assent, nor can it flow from
any known natural law ; indeed if it were true it would not
shew itself by the usual mode of experimenting, as we can
readily imagine one part of the water having l-4th, another
l-5th, both being distinct parts of the whole, but so mixed
with each other in the water that no result is perceived.

4. " If a quantity of water free from air be agitated with
a mixture of two or more gases, such as atmospheric air,
the water will absorb portions of each gas the same as if
they were presented to it separately in their proper density."

5. " If water impregnated with any one gas (as hydrogenous)
be agitated with another gas equally absorbable (as azotic),
there will apparently be no absorption of the latter gas ;
just as much gas being found after agitation as was intro-
duced to the water ; but upon examination the residuary gas
will be found a mixture of the two, and the parts of each, in
the water, will be exactly proportional to those out of the
water."

" 10. Pure distilled water, rain and spring water, contain
nearly their due share of atmospheric air ; if not, they quickly
acquire that share by agitation in it, and lose any other gas
they may be impregnated with. It is remarkable however
that water by stagnation in certain circumstances loses part
or all of its oxygen, notwithstanding its constant exposition
to the atmosphere. This I have uniformly found to be the
case in my large wooden pneumatic trough, containing
about 8 gallons. * * * * The quantity of azotic ^s is
not materially diminished by stagnation, if at all." He has
not here considered the action of the organic substances.

Theory of the absorption of gases by water, p. 283.

" 1. All gases that enter into water and other liquids, by
means of pressure, and are wholly disengaged again by the

HISTOKY OF THE ATOMIC THEOBY. 47

removal of that pressure, are mechanically mixed with the
liquid, and not chemically combined with it."

He had already mentioned Dr. Henry's discovery, that
the quantity of gas absorbed is as the density or pressure.

** 2. Gases so mixed with water, &c., retain their elasticity
or repulsive power amongst their own particles, just the same
in the water as out of it, the intervening water having no
other influence in this respect than a mere vacuum."

"3. Each gas is retained in water by the pressure of gas of
its own kind incumbent on its surface abstractedly considered,
no other gas with which it may be mixed having any per-
manent influence in this respect."

" 4. When water has absorbed its bulk of carbonic acid gas,
&c., the gas does not press on the water at all, but presses
on the containing vessel just as if no water were in. When
water has absorbed its proper quantity of oxygenous gas,
&c., that is, l-27th of its bulk, the exterior gas presses on
the surface of the water with 26-27 ths of its force, and on
the internal gas with l-27th of its force, which force presses
upon the containing vessel, and not on the water. With azotic
and hydrogenous gas the proportions are 63-64ths and l-64th
respectively. When water contains no gas, its surface must
support the whole pressure of any gas admitted to it, till the
gas has in part forced its way into the water."

"5. A particle of gas pressing on the surface of water is
analogous to a single shot pressing upon the summit of a
square pile of them. As the shot distributes its pressure
equally amongst all the individuals forming the lowest
stratum of the pile, so the particle of gas distributes its
pressure equally amongst every successive horizontal stratum
of particles of water downwards, till it reaches the sphere
of influence of another particle of gas. For instance, let
any gas press with a given force on the surface of water,
and let the distance of the particles of gas from each other
be to those of water as 10 to 1, then each particle of

48 MEMOIR OF DR. DALTON, AND

gas must divide its force equally amongst 100 particles
of water, as follows : It exerts its immediate force upon 4
particles of water; those 4 press upon 9, the 9 upon 16,
and so on according to the order of square numbers, till
100 particles of water have the force distributed amongst
them; and in the same stratum each square of 100, having
its incumbent particle of gas, the water below this stratum is
uniformly pressed by the gas, and consequently has not its
equilibrium disturbed by that pressure."

" When water has absorbed 1-27 th of its bulk of any gas,
the stratum of gas on the surface of the water presses with
26-27ths of its force on the water, and with l-27th of its
force on the uppermost stratum of gas in the water ; the dis-
tance of the two strata of gas must be nearly 27 times the
distance of the particles in the incumbent atmosphere, and
9 times the distance of the particles in the water. This
comparatively great distance of the inner and outer atmos-
phere arises from the great repulsive power of the latter, on
account of its superior density, or its presenting 9 particles
of surface to the other I. When l-64th is absorbed, the
distance of the atmospheres becomes 64 times the distance of
two particles in the outer, or 16 times that of the inner.
The annexed views of perpendicular and horizontal strata of
gas in and out of water will sufficiently illustrate these
positions." *

" 7. An equilibrium between the outer and inner atmos-
pheres can be established in no other circumstance than that
of the distance of the particles of one atmosphere being the
same or some multiple of that of the other; and it is probable
the multiple cannot be more than 4. For in this case the dis-
tance of the inner and outer atmospheres is such as to make
the perpendicular force of each particle of the former or those
particles of the latter that are immediately subject to its influ-

• A plate accompanied this.

HISTORY OF THE ATOMIC THEORY. 49

ence, physically speaking, equal; and ^he same may be
observed of the small lateral force."

" 8. The greatest difficulty attending the mechanical hypo-
thesis arises from different gases observing different laws.
Why does water not admit its bulk of every kind of gas alike?
This question I have duly considered, and although I am not
yet able to satisfy myself completely, I am nearly persuaded
that the circumstance depends upon the weight and number of
the ultimate particles of the several gases; those whose parti-
cles are lightest and single being least absorbable, and the
others more, according as they increase in weight and com-
plexity— (subsequent inquiry made him think this less
probable). An inquiry into the relative weights of the ulti-
mate particles of bodies is a subject, as far as I know,
entirely new; I have lately been prosecuting this inquiry
with remarkable success. The principle cannot be entered
upon in this paper; but I shall just subjoin the results, as
for as they appear to be ascertained by my experiments."

He then gives a list of relative weights of 21 substances,
constituting the first attempt to form a table of atomic
weights.

" Table of the relative weights of the ultimate particles of
gaseous and other bodies.

Hydrogen 1

Azot... 4.2

Carbone 4.3

Ammonia 5.2

Oxygen 5.5

Water 6.5

Phosphorus 7.2

Phosphuretted hydrogen 8.2

Nitrous gas 9.3

Ether 9.6

Gaseous oxide of carbone 9.8

H

50 MEMOIR OF DR. DALTON, AND

Nitrous oxide 13.7

Sulphur 14.4

Nitric acid 15.2

Sulphuretted hydrogen 15.4

Carbonic acid 15.3

Alcohol 15.1

Sulphureous acid 19.9

Sulphuric acid 25 .4

Carburefted hydrogen from stagnant water 6.3

Olefiantgas 5.3"

I have given as much as possible, in his own words, the
most important points attended to by Dalton up to this
date. It was not my intention to inquire into the particulars
relating to the novelty of the views taken by him, except
on the atomic theory, and have therefore purposely left out
any such opinions as might require discussion; nor have I
shewn in all cases where advancing science has differed from
his results. Some things in the papers alluded to were bold
and strikingly new, some things are improvements on the old,
some are mere re-statements of the old, but all is done in a
firm, clear, and determined manner, as by a master in the
business, going to the real point of difficulty in every case,
and at all times avoiding unimportant details or vain orna-
ment. He drives on like a new settler, and clears the
ground before him, leaving it rather rugged it is true;
nevertheless it is resolutely cleared.

HI8T0BY OF THE ATOMIC THEOHY. 51

CHAPTER III.

daltdn's social life.

We now approach the most important discovery of Dalton,
and before entering upon it, it may be well to acquaint the
reader with the general character and appearance of the man
in his vigour. It is not my intention, as before stated, to
amuse myself or readers with many little incidents of his life,
nor can we gain by looking at such a character apart from
the student of nature ; but it is needful to give some slight
account of the appearance and habits of the agent by which
such valuable knowledge of natural law has been gained.
On his habits, Miss Johns's Journal, lent me freely by Mr.
WooUey, is the best authority. The Rev. W. Johns, once
a colleague of Dalton's at the academy, had a school in
George-street, near the Literary and Philosophical Society,
which had given up a portion of its room to Dalton. In
the autumn of 1804, Mrs. Johns saw him casually pass, and
asked him why he never came to see them. Dalton said, " I
do not know; but I will come and live with you, if you will
let me." He did so, and took possession of the only bedroom
at liberty, sitting with the family. In this family he lived
for twenty-six years in the greatest amity, until Mr. Johns,
giving up the school, sought a purer air in the suburbs of the
town.

The portrait which is appended to this memoir, is from a
picture by Allen, presented to the society by that painter on
the occasion of Dalton being made president. It represents
him in the vigour of life, and must of course be a more suit-
able representation of the man than those taken in old age,
although one at least of those by Stephenson is an excellent
portrait of a late period, and a beautiful engraving.

52 MEMOIR OF DR. DALTON, AND

He was rather above the middle size, five feet seven inches.
Mr. Giles, who read a memoir of him to the Manchester
Society, and who was his pupil, says that " he was robust,
athletic, muscular, and stooped slightly as if hasting forward,
for he was a rapid walker. His countenance was open and
manly. His voice was deep and gruff; and his lectures were
by no means interesting, except to those who were satisfied
with matter independent of style : he even spoke in a careless
and mumbling manner." He was a Quaker, as has been said,
and dressed in their peculiar manner, taking care that every
article of dress should be of the finest texture, but avoiding
the extreme of formality. In his general conversation he
did not adopt their style ; and never gave any opinion on
religious subjects. His most intimate friends found him re-
served on such points, although at times they found that
there was in him great reverence and deep feeling. But he
evidently did not think much on religious subjects, and seems
not even to have formed strong opinions upon them, giving
way to the opinions of those around him, like one unable or
unwilling to form them for himself. If this were the case
only with such subjects as are peculiarly religious, we might
suppose that it arose simply from a want of agreement with
current opinions which he was unwilling to disturb, but as
he stood in the same attitude towards metaphysical opinions,
we may fairly conclude that those faculties which discuss
the moral and intellectual history and position of man, were
not highly developed in Dalton. It would not be wise to
conclude that they were weak, because we find that he had
a great power of concentration, and in his ardent study of a
subject he seems to have allowed the rest of his mind to be
satisfied with meditative culture. In early life he seemed
inclined to answer moral and metaphysical questions in the
Gentleman's Magazine; and occasionally a lady would in-
duce him to write a few lines of such poetry as a well-
educated man is generally able to write. But his life was

HISTORY OF THE ATOMIC THEORY. 53

spent in his laboratory, and all subjects not connected with
his pursuits were much neglected; he might have said of
their cultivation, as he said when asked why he never got
married, " I never had time."

He rose at about eight o'clock in the morning; if in winter,
went with his lantern in his hand to his laboratory, lighted
the fire, and came over to breakfast, when the family had
nearly done. Went to the laboratory and staid till dinner
time, coming in a hurry when it was nearly over, eating
moderately and drinking water only. Went out again and
returned at about five o'clock to tea, still in a hurry, when
the rest were finishing. Again to his laboratory till nine
o'clock when he returned to supper, after which he and Mr.
Johns smoked a pipe, and the whole family seems much to
have enjoyed this time of conversation and recreation after
the busy day. Dr. Schunck, who dined there as a child at
school, says he never appeared in a hurry.

He was rather silent, especially if the company were large,
but an attentive listener, whilst he occasionally introduced some
short sentence of dry humour. With a few of his intimate friends
he enjoyed much a lively conversation, but does not seem to
have been fitted for dealing with men assembled in large
numbers, either in public or private. This did not arise from
any want of self-possession, which is said never to have been
known to be ruffled: an illustration of this is given in
the following. When in using the air-pump at a lecture
a glass vessel burst, making a considerable noise and causing
the ladies to scream, he simply said, " that is more than I in-
tended, it's broken," and went on again. His disinclination
to speak made him, as a teacher, by no means communica-
tive ; he allowed his pupils to learn, and willingly answered
a question, but during the most of the time he was attending
to his experiments, thinking, probably, that they were much
better off than he ever was to have some one to apply to if a
difficulty arose.

54 MEMOIR OF DR. DALTON, AND

His habits were careful and economical, some say parsimo-
nious, but he was by no means wanting in generosity, and
gave fifty pounds to the building of the new Meeting House,
at a time when he certainly could have had but very little.
Such men do not often seek amusements, and he had only
one, a remnant of Cumberland, which he seemed never to
forget, at the same time also a wholesome exercise. Every
Thursday afternoon, about two o'clock, he went outside the
town to the " Dog and Partridge," now far within Manches-
ter, and played a few games at bowls. This he seems to have
thoroughly enjoyed, watching the bowls with the greatest
anxiety, and by his constant movements indicating, as people
are apt to do, the way in which they wish the bowl to move,
as if endeavouring to influence it. He shewed even there a
glimmer of the latent enthusiasm of his mind. He played
a fixed number of games and then ceased, took tea at the
inn, smoked his pipe, and went to his laboratory. Between
twelve and one he usually went to the Portico to read the news-
papers, but did not strongly speak on political subjects, so
that even the Johns family did not for a long time know that
he was Conservative in politics. At the same time Mr. Giles
says he was a Liberal, always voting for Liberals, so that
we may call him a liberal Conservative, which however
indefinite, is somewhat the character of such a man, con-
siderate, desirous of improvement, but not inclined to violent
change.

His great delight was to visit the hills of Cumberland where
he first studied the clouds and the aurora, and when the usual
day of June had come, old Matthew Jobson came out of his
cottage under the slopes of Helvellyn, and looked out for
Dalton and his instruments. He ascended the hill from thirty
to forty times during his life, walking rapidly and with ease,
generally keeping before any party who accompanied him, so
as on one occasion to have brought out the exclamation from a
friend, " John, I wonder what thy legs are made of." In later

HISTORY OF THE ATOMIC THEOEY. 55

life occasionally he was accompanied by some of the younger
members of the family to whom he was now as a relation, and
we can well believe Miss Johns, when she says, " that to those
who have seen him only on ordinary occasions, it is impossible
to convey an idea of his enthusiasm on those occasions. He
never wearied." Jonathan Otley, the veteran guide, at
Keswick, who has spent his life mapping, describing, and
showing the country around, often accompanied Dalton, and
he has in a journal given an account of some of their excur-
sions* These were undertaken partly with a view of " bring-
ing into exercise a set of muscles, which would otherwise have
grown stiff," as Dalton said, and partly to make meteorological
observations, or to bring down air for analysis from the highest
points of the county, gas from the floating island, and minerals
from every hill.

In order to give his habits of thought on objects not scien-
tific, a few of his letters may be introduced with advantage; at
the same time they will give an account of some portions of
his life, which would lose much of their interest if the words
of another were alone used.

Having been invited to lecture at the Royal Institution, he
thus describes his visit in a letter to his brother, February 1st,
1804. His first visit to London had been made in 1792.

" Dear Brother, I have the satisfaction to inform thee that
I returned safe from my London journey, last seventh day,
having been absent six weeks. It has, on many accounts,
been an interesting vacation to me, though a laborious one.
I went in a great measure unprepared, not knowing the nature
and manner of the lectures in the institution, nor the apparatus.
My first was on Thursday, December 22nd (1803), which
was introductory, being entirely written, giving an account of
what was intended to be done, and natural philosophy in
general. All lectures were to be one hour each, or as near as
might be. The number attending were from one to three
hundred of both sexes, usually more than half men. I was

56 MEMOIR OF DR. DALTON, AND

agreeably disappointed to find so learned and attentive an
audience, though many of them of rank. It required great
labour on my part to get acquainted with the apparatus and
to draw up the order of experiments and repeat them in the
intervals between the lectures, though I had one pretty expert
to assist me. We had the good fortune, however, never to
fail in any experiment, though I was once so ill prepared as
to beg the indulgence of the audience, as to part of the lecture,
which they most handsomely and immediately granted me by
a general plaudit. The scientific part of the audience was
wonderfully taken with some of my original notices relative
to heat, the gases, &c., some of which had not before been
published. Had my hearers been generally of the description
I had apprehended, the most interesting lectures I had to give,
would have been the least relished, but as it happened, the
expectations formed had drawn several gentlemen of first-rate
talents together ; and my eighteenth, on heat, and the cause
of expansion, &c., was received with the greatest applause,
with very few experiments. The one that followed was on
mixed elastic fluids, in which I had an opportunity of
developing my ideas, that have already been published on the
subject more fully. The doctrine has, as I apprehended it
would, excited the attention of philosophers throughout
Europe. Two journals in the German language, came
into the Royal Institution, whilst I was there, from Saxony,
both of which were about half filled with translations of the
papers I have written on the subject, and comments on them.
Dr. Ainslie was occasionally one of my audience, and his sons
constantly : he came up at the concluding lecture, expressed
his high satisfaction, and he believed it was the same senti-
ment with all or most of the audience. I was at the Royal
Society one evening, and at Sir Joseph Banks's another. This
gentleman I had not, however, the pleasure of seeing, he
being indisposed all the time I was in London.

" I saw my successor, William Allen, fairly launched ; he

HISTORY OF THE ATOMIC THEORY. 57

gave his first lecture on Tuesday preceding my conclusion.
I was an auditor in this case, the first time, and had an
opportunity of surveying the audience. Amongst others of
distinction the Bishop of Durham was present.

" In lecturing on optics I got six ribbands, blue, pink, lilac,
and red, green, and brown, which matched very well and told
the curious audience so. I do not know whether they
generally believed me to be serious, but one gentleman came
up immediately after and told me he perfectly agreed with
me : he had not remarked the difference by candle light."

This letter concludes characteristically by " The rain has
been 27^ inches last year."

Like many students whose nerves are not easily affected,
Dalton liked tobacco. A thorough explanation of its action
on various constitutions seems to have hitherto escaped the
research of medical men, most of them being content either
to admire it, or to detest it, according as it may suit them-
selves. The following letter to Mr. John Rothwell gives
Dalton's taste.

London, Jan. 10th, 1804.

" I was introduced to Mr. Davy, who has rooms adjoining
mine in the Royal Institution : he is a very agreeable and
intelligent young man, and we have interesting conversations
in an evening : the principal failing in his character is, that
he does not smoke. Mr. Davy advised me to labour my first
lecture : he told me the people here would be inclined to form
their opinion from it; accordingly I resolved to write my first
lecture wholly ; to do nothing but to tell them what I would
do, and enlarge on the importance and utility of science. I
studied and wrote for nearly two days, then cjjilculated to a
minute how long it would take me reading, endeavouring to
make my discourse about fifty minutes. The evening before
the lecture, Davy and I went into the theatre : he made me
read the whole of it, and he went into the furthest comer;
then he read it, and I was the audience; we criticised upon
I

58 MEMOIR OF DR. DALTON, AND

each other's method. Next day I read it to an audience of
about 150 or 200 people, which was more than were expected.
They gave a very general plaudit at the conclusion, and
several came up to compliment me on the excellence of the
introductory. Since that time I have scarcely written any-
thing ; all has been experiment and verbal explanation. In
general my experiments have uniformly succeeded, and I have
never once faltered in the elucidation of them. In fact, I
can now enter the lecture room with as little emotion nearly
as I can smoke a pipe with you on Sunday or Wednesday
evenings."

In 1807 he gave a similar course of lectures in Edinburgh,
on which the following addressed to his friend, the Rev. W.
Jones, may be read with interest.

Edinburgh, April I9th, 1807.
" Respected Friend,

As the time I proposed to be absent is nearly expired,
and as my views have recently been somewhat extended, I
think it expedient to write you for the information of enquirers.
Soon after my arrival here I announced my intention by
advertisement of handbills ; I obtained introduction to most of
the professional gentlemen in connection with the college, and
to others not in that connection, by all of whom I have been
treated with the utmost civility and attention ; a class of eighty
appeared for me in a few days ; my five lectures occupied me
nearly two weeks ; they were finished last Thursday, and 1
was preparing to leave the place, and return by Glasgow, to
spend a week. But several of the gentlemen who had
attended the course represented to me that many had been
disappointed in not having been informed in time of my inten-
tion to deliver a course, and that a number of those who had
attended the first course would be disposed to attend a second.
I have been induced to advertise for a second, which, if it
succeeds, will commence on Wednesday, the 22nd, and be
continued daily, till the conclusion. This will detain me a

HISTOKT OF THE ATOMIC THEOBT. 59

week yet; I then set off for Glasgow, where I may be
detained for a week or more, so that I see no probability of
reaching Manchester before the beginning of May, to which
I look forward with some anxiety. Hitherto I have been
most highly gratified with my journey ; it is worth coming
100 miles merely to see Edinburgh. It is the most romantic
place and situation I ever saw ; the houses touch the clouds ;
at this moment I am as high above the ground as the cross
on St. James's spire ; yet there is a family or two above me ;
in this place they do not build houses side by side as with you,
they build them one upon another, nay, they do what is more
wonderful still, they build one street upon another ; so that
we may in many places see a street with the people in it,
directly under one's feet, at the same time that one's own
street seems perfectly level and to coincide with the surface of
the earth. My own lodgings are up four flights of stairs from
the front street, and five from the back. I have just 100 steps
to descend before I reach the real earth. I have a most
extensive view of the sea ; at this moment I see two ships ;
and mountains across the Firth of Forth, at the distance of
thirty miles ; to look down from my windows into the street
at first made me shudder, but I am now got so familiar with
the view, that I can throw up the window and rest on the
wall, taking care to keep one foot as far back in the room as
I can, to guard the centre of gravity. The walks about
Edinburgh are most delightfully romantic. The weather is
cold; ice every morning, and we had a thick snow a few days
ago. Upon walking up on to an eminence I observed all the
distant hills white; the nearer ones speckled ; I saw five or six
vessels just touching the horizon; they seemed to be about
ten or twelve miles off, and their white sails looked like specks
of snow on the sea. I saw a dozen or two at anchor in the
river, and a most charming view of the Fifeshire hills on the
other side of the Firth. Adieu. My best regards to you all."

J. Dalton.

60 MEMOIR OF DE. DALTON, AND

Again, from London, December 27th, 1809, when giving
another course of lectures, he writes to Mr. Jones, after some
pleasant gossip about his fellow-travellers : —

" On Tuesday I spent greater part of the day (morning
they call it here) with Mr. Davy in the laboratory of the
Royal Institution. Sir I. Sebright, M.P., who is becoming
a student of chemistry, was present. We had a long discus-
sion. In the evening I walked three miles into the city, to
Pickford's, to look after my boxes ; I found them there, but
as they promised to send them next day I did not take them.
They disappointed me. On Wednesday I attended Mr.
Bond's lecture on astronomy, and prepared for mine the
next day. On Thursday, at two, I gave my first lecture.
Mr. Pearson, a former acquaintance, went home with me
after the lecture, and w^e had a long discussion on mechanics.
Mr. Davy had invited me to dine with the club of the Royal
Society, at the Crown and Anchor, at five o'clock, but I was
detained till near six ; I got there and called Davy out ; all
was over ; the cheese was come out. I went, therefore, to
the nearest eating-house I could find to seek a dinner ; look-
ing in at a window I saw a great heap of pewter plates and
some small oblong tables covered with cloths. I went in and
asked for a beefsteak ; *' no." What can I have? " boiled beef.'*
Bring some immediately. There was nothing eatable visible
in the room, but in three minutes I had placed before me a
large pewter plate covered completely with a slice of excel-
lent boiled beef swimming in gravy, two or three potatoes,
bread, mustard, and a pint of porter. Never got a better
dinner. It cost me ll^d. I should have paid 7s. at the
Crown and Anchor. I then went to the Royal Society and
heard a summary of Davy's paper on chemistry, and one of
Home's on the poison of the rattlesnake : Sir J. Banks in the
chair. Davy is coming very fast into my views on chemical
subjects. On Friday I was preparing for my second lecture.
I received a visit from Dr. Roget. On the evening I was

HISTOEY OF THE ATOMIC THBOBY. 61

attacked with sore throat. I sweated it well in the night
with cloathing, but it was bad on Saturday, and I was
obliged to beg a little indulgence of my auditors on the score
of exertion. However, I got through better than I expected.
I kept in on Sunday and Monday and got pretty well re-
cruited. On Tuesday I had my third lecture, after which I
went to dine at a tavern to meet the chemical club. There
were five of us, two of whom were Wollaston and Davy,
secretaries of the Royal Society; we had much discussion
on chemicals. Wollaston is one of the cleverest men I have
yet seen here. To-day, that is Thursday (for I have had
this letter two or three days in hand), I had my fourth lec-
ture. I find several ingenious and inquisitive people of the
audience. I held a long conversation to-day with a lady on
the subject of rain-gauges. Several have been wonderfully
struck with Mr. Ewart's doctrine of mechanical force. I
believe it will soon become a prevalent doctrine. 1 should
tell Mrs. J. something of the fashions here, but it is so much
out of my province, that I feel rather awkward. I see the
belles of New Bond-street every day, but I am more taken
up with their faces than their dresses. 1 think blue and red
are the favourite colours. Some of the ladies seem to have
their dresses as tight round them as a drum, others throw
them round them like a blanket. I do not know how it
happens, but I fancy pretty women look well any how.

I am very regular with my breakfast, but other meals are
so uncertain that I never know when or what. Hitherto I
have dined at from two to seven o'clock; as for tea I generally
have a cup between nine and ten, and, of course, no supper.
I am not very fond of this way of proceeding. They say
things naturally find their level, but I do not think it is the
case in London. I sent for a basin of soup the other day
before I went to lecture, thinking I should have a good three-
penny worth, but I found they charged me one shilling and
ninepence for a pint, which was not better than some of our

62 MEMOIR OF DR. DALTON, AND

Mary's broth. Of course, I could not digest much more of
the soup."

Again, the year after,

London, Jan. 29th, 1810.

" You may perhaps have heard from Dr. Henry that I
have been nearly as ill as formerly, that 1 have been nearly
poisoned since I came here. I had been about three weeks
when I discovered it was the porter which produced the
effects.* I have not had a drop since, and have never had
any more of the symptoms.

" I have had a pretty arduous work, as you may imagine,
having had three lectures to prepare each week; to attend
two others, and to visit and to receive visits occasionally
besides. I find myself just now in the focus of the great and
learned of the metropolis. On Saturday evening I had a
discussion with Dr. Wollaston, and a party at Mr. Lowry's.
On Sunday evening, last night, I was introduced to Sir
Joseph Banks, at his house, by Sir John Sebright. Sir
Joseph said, ' Oh, Mr. Dalton, I know him very well ; glad
to see you; hope you are well, &c.' There were forty or
more of the leading scientific characters present, many of
whom were my previous acquaintance, such as Sir Charles
Blagden, Drs. Wollaston, Marcet, Berger, and Roget;
Messrs. Cavendish, Davy, Tennant, Lawson, &c. ; we had
conversation for about an hour or more in Sir Joseph's
library, when the company dispersed. To judge from the
number of carriages at the door, it might be a court levee.

" I paid a visit, in company with Dr. Lowry, to Dr. Rees,
the other day; we spent an hour in conversation in the
doctor's library. The doctor seems a worthy philosopher of
the old school; his evening lucubrations are duly scented
with genuine Virginia."

• Lead had been found in it. This was probably owing to the use of lead
pumps, a very common and dangerous custom, whether used as is commonly
the case in public-houses, at least in this Neighbourhood, to pump the malt
liquor from the cellar, or for water for domestic supply.

HISTOEY OF THE ATOMIC THEORY. 63

Sir Humphrey Davy's opinion of Dalton, given in Dr.
Henry's recent life, seems to contain rather harsh and un-
pleasant expressions, and I think scarcely fair suggestions.
He could not have known the man otherwise than externally ;
nor does he seem to have known well the history of his dis-
coveries. I shall allude to it more when speaking of Dalton
as a philosopher; as to the man I only collect the opinions
of others, and give a few examples of his character from
his letters and actions. His brother. Dr. Davy, also says,
** Mr. Dalton's aspect and manner were repulsive. There
was no gracefulness belonging to him. His voice was harsh
and brawling; his gait stiflf and awkward; his style of writing
and conversation dry and almost crabbed. In person he was
tall, bony, and slender. (1809-10.) He never could learn
to swim; on investigating this circumstance he found that
his specific gravity was greater than that of water, and he
mentioned this in his lectures on natural philosophy in
illustration of the capability of different persons for attaining
the art of swimming." But he adds, " independence and
simplicity of manner and originality were his best qualities.
Though in comparatively humble circumstances he main-
tained the dignity of the philosophical character." So many
" best " qualities are seldom found in one man.

This word brawling was unintelligible to me until Dr.
Schunck suggested drawling, as the true meaning. Brawl-
ing is unintelligible in connection with such a retiring man.
Dr. Schunck says, " no one who saw him could call his
appearance repulsive. I recollect him from my childhood
and never saw it; and children are very susceptible to re-
pulsive appearance in people. He was, I think, good
looking; only his deep set eyes were against him." At
any rate, there is no connection between brawling and
Dalton. When I saw him his mind was quite broken down ;
but I agree with my friend, Dr. Schunck, that he was agree-
able to look upon.

64 MEMOIR OF DR. DALTON, AND

A writer in the Quarterly Review, Vol. XC VI., who had
heard him lecture, gives him an unfavourable manner,
saying " his voice was harsh, indistinct, and unemphatical,
and he was singularly wanting in the language and power of
illustration, needful to a lecturer on these high matters of
philosophy, and by which Davy and Faraday have given
such lustre to their discoveries. Among other instances of
his odd appropriation of epithets, we recollect that in treating
of oxygen, hydrogen, nitrogen, &c., those great elements
which pervade all nature, he generally spoke of them as
^ these articles,' describing their qualities with far less earnest-
ness than a London linen draper would shew in commending
the very different articles which lie on his shelves."

As to his style of writing, it is before us to judge. These
letters shew nothing crabbed. The specimens of scientific
writing given are equally free from such blame ; and although
there are different styles in his own works, I consider that
generally his scientific writing is agreeable to read, nor is it by
any means more " dry" than the average scientific memoirs.

Still we must consider that his appearance or manner was
much against him in the eyes of some persons, the evidence
being so strong, but the following letter will show that he
was not of a repulsive cast of mind. These letters, from
which I quote, were written home to Mr. Johns for him-
self and the family to read, as may be supposed, and shew,
instead of a repulsive, an exceedingly amiable disposition.
He was lecturing at Birmingham, and he writes: —

March 17th, 1825.

" We left the Bridgewater Arms, three middle sized and
middle aged gentlemen in a small coach; there was room
for a thin lady opposite my left hand friend, and I was
beginning to think he might have the advantage of me in
two respects. We drove down to the Palace Inn, and there
I saw a corpulent old gentleman set off towards us much in
the shape of a sack of malt ; he came up in as straight a line

HISTOBY OF THE ATOMIC THEORY. 65

as he well could, and having partly entered, my companion
called out * oh ! ' with a long continuance. His toes were
unfortunately the sufferers. The old man had not yet got
settled in his contracted berth before he informed us that he
thought the coach a very small one. Indeed, his hat nearly
touched the roof when sitting. At Stockport, changed
horses, a famous lusty woman having brought them out, her
husband (I suppose) having been up late the night before.
The old gentleman told us a friend of his travelling in Wales
having occasion to call at an inn to breakfast, found the
housemaid busy rubbing the irons ; she left them, and took
his horse to stable. Where is the hostler, said he, that was
here the last time I was this way? ' I was him,' said the girl.
The landlord told his guest he never had a better hostler in
his life than she was. We got near to Macclesfield, when
my opposite companion, who did not know England as well
as Ann says she knows Europe, asked his fellow-traveller
whether we were in Staffordshire or Warwickshire. ♦ • •
At Newcastle our geographer remarked that there were two
Newcastles at a great distance from each other ; ' Newcastle-
upon-Tyne,' says he, * is that in England or in Scotland?*
After a short pause, the maltster says, ' it is in Cumberland,
I think.' ' No. In Northumberland,' said my left hand
friend.

I have been here (Birmingham), at one of the show rooms,
to see the new lions, since I was last here. There are many
good things; amongst other things, they have got new
banisters, for stairs. What is it. Mahogany ? No. Lignum
vitae ? No. Ebony ? No. No sort of wood, nor metal either,
it is glass, cut glass."

London, May 15th, 1825.

" I agreed to go with Mr. Lowe, one of the superintendents
of the gas works, whom I was previously acquainted with, to
spend the night. It is at Highgate, four miles on the Nortli-
road; we took a stage at nine, and arrived in about forty

K

66 MEMOIR OF DR. DALTON, AND

minutes ; after walking up a steep hill, we came to a row of
most delightfully situated houses, on an eminence, looking
down on the city and the adjacent country. Whether by
night or by day it is delightful ; at night, we see the lights of
the city forming a circle around us; the general effect is most
curious. A darkish cloud hung over the whole foreground ; the
lights from London illuminated that part over it, whilst on
this side it was dark, and on the other side dark, so as to give
the appearance of a luminous cloud, interposed between two
black clouds. The night was still and fine, and Mr. L.
promised me I should hear the nightingale; for one or two
sung every night from a grove, 100 yards below his house.
We smoked our segars till twelve, then looked out and
listened ; all silent, no nightingale. We went to bed about
three, I was awoke by the melodious song of the nightingale,
which continued, without any interruption, till four o'clock.
Soon after three I also heard the second and third best singing
birds that we have, according to Mr. Blackwall, and the first,
or nightingale, all singing together. My bedroom window
fronted the S.E. In the morning, at eight, I took hold of
the blind string with one hand, and put my other to the
opposite side to help it up, as usual, with most others ; but
to my surprise it spun up to the top of the window of its own
accord, in a moment, and such a view as I never witnessed
presented itself, except at St. Cloud, near Paris. For half a
mile before me rose the tops of trees, from a beautiful grove,
belonging to Mrs. Coutts, her house chimneys popping up
on the right ; over the tops of the trees the country presented
itself, interspersed with houses, and beyond, London with its
spires; St. Paul's dome, like Helvellyn, right in the front;
the river, the Kent hills over London, &c., &c., the sun
shining clear, the birds singing, &c., &c. Quite at the foot
of my window, a kind of verandah, entwined with shrubs be-
low, about 100 yards square of descending ground, so covered
with shrubs as to hold two or three shady seats, and some

HISTORY OF THE ATOMIC THEORY. 67

large shrubs, looking like a wilderness, and in the middle a
little plot of green ground and a knot of flowers. In short, it
was multum in parvo with a witness. This is the very house
occupied by the late Mr. Joyce."

To Mr. Johns, when absent from Manchester.

July 2nd, 1825.

" Yesterday I dined at Dr. Henry's, meeting Professor
Almroth, of Stockholm, and a party, together with his own
young family and Miss Bailey. Professor Almroth break-
fasted with me this morning. He is well read in Shakespere,
Sir Walter Scott, and the German literature, as well as in
Shimistry,

" You will have a new chapel to go to when you come here.
The g^reat water hole opposite has now a chapel on it, for
Baptists, they say. * * * * I am nearly ready for a
jaunt, but whether north or west I do not know till my
stick falls."

We see from these letters that he was accustomed to
lecture occasionally in all parts of the country, when invited,
and we see also enough to let us judge a little of his temper.
They are full of very simple kindly feeling, the very act of
writing home so many details betokens a disposition to please,
and entirely precludes every accusation of vanity or that
absurd appearance of separation from his fellows, which we
find so frequently the production of bigotry and of ignorance,
but which we too often call by the name of dignity. We find
him exceedingly pleased with the attentions of scientific men ;
he had, of course, frequent visits from such as came to Man-
chester, and foreigners of distinction seem to have pleased
him as much as the young members of the family where he
resided. At the same time he was tenacious of his opinions,
and we find that in describing his conversations with men
of science, he generally calls them discussions, and generally
on scientific subjects we find him too much standing up for
his own rights, as his results appeared to him to be. This

68 MEMOIR OF DR. DALTON, AND

arose from a peculiarity of mind which seems to have been
too much developed in him, as in those also where obser-
vation and experience are so tenaciously remembered as
to become the only groundwork of opinion, and where
the arguments of others are as mere fiction, having no
influence upon the reasoning powers. Acting in this spirit,
he discouraged reading, and prevented the Literary and
Philosophical Society from obtaining a sufficient supply of
books. He said, " I could carry all the books I have ever
read on my back."* In this, he was evidently forgetting how
diverse were the faculties of mankind, and acting also in
ignorance of the fact, that he was himself suffering from a
want of reading, although it is probably true that he was
a gainer in another direction from the same cause. But in
summing up features of characters, we find great antagonism
in our results, so that we are in error when we make up a
very uniform design from what is too often a hastily prepared
patchwork, and known to be so by the owners themselves,
but which they are prevented from completing by circum-
stances, if not by time, which limits the progress of all. He,
in fact, is often the great man who allows himself to act
onesidedly, not for his own pleasure or profit, but because
the struggle which he has to maintain, needs all energies
to be concentrated on one point of attack.

In this way we may view Dalton. We must see him also
as a man having limited assistance from the knowledge of
others, ignorant of many of the elegant and easy methods of
procuring knowledge and illustrating facts which have be-
come the common inheritance of universities, and accustomed
to the society of few only who had similar studies ; and when
meeting with his contemporaries from capital cities, forgetting
that they were not like him, completely immersed in the
study of nature, but were also expected to cultivate the soiree
and the dinner table. Still sociality was not entirely checked

• Mr. Woolley is my authority.

HISTORY OF THE ATOMIC THEORY. 69

in Dalton, although it was under subjection to routine. This
was seen in the regular manner in which he went on Sunday
to dine, at Mayfield, with Mr. Neild, even if the host were not
at home, and in the regular manner in which he joined the
family of Mr. Johns every evening, enjoying the society of the
younger members who had grown up from childhood under
his eye, and under the same roof, and in the great pleasure
he had in taking them with him in his summer excursions. It
was a mild enjoyment, allowing of little enthusiasm, this was
reserved for the sterner aspects of nature on the summits of
Scawfell or Helvellyn ; but it was his nature to be calm, a
violent life does not suit the inquirer into nature.

He was simple in his habits by nature and by education,
but still more so from his pursuits. Such are always found to
be disturbed when wealth, by enlarging the establishment,
claims too much the care of the possessor, and when work,
ceasing to be urgent, allows us to imagine that the cultivation
of an acquaintance is the great business of our life. To the
courtly especially, he seemed morose, but that it was merely
a question of form, and not of inward feeling, we see addi-
tional proof in the letter where he makes a similar complaint
of Sir H. Davy, as lacking that geniality which he jocularly
represents under the symbol of tobacco.

To a certain extent he was separated from society by the
constancy of his work. Many have been separated, and
separated themselves for idleness, but for work, few; and
whilst the world is overflowing with those who would willingly
give themselves to the pleasure of social intercourse, an
occasional exception for a higher purpose stands forth as a
subject for our admiration, surely not for a censure.

Dalton never married, he had not time, he said. In early
life his position prevented him, in middle life constant work,
when he seems to have been struggling for an independency,
not knowing that it would come to him with ease as soon as
his failing strength demanded it. This desire to become in-

70 MEMOIR OF DR. DALTON, AND

dependent of his work induced in him an undue amount of
care in the accumulation of his savings: we may consider
them as the representatives of a certain amount of time
entirely lost to all but his heirs. At the same it is to be
remembered that he was accumulating his savings for a time,
when he could no longer be able to work, and the simplicity
and self-denial of such a course, instead of being worthy of
blame, is a virtue, which, unfortunately, is not of sufficient
occurrence. This virtue gave him the opportunity of showing
kindness to many of his friends, and of helping such as were
in need.

He was on terms of friendship with several ladies whom
he greatly admired, and there is little doubt that in one case
in early life the admiration was that of love. Whether the
fact of the lady's engagement to another aifected him for any
length of time with disappointment, is what his reserved
nature never told to any one, but we are left to guess that
the attachment was strong, when late in life he could not
read without emotion, and even tears, some verses the lady
had written, or allow any one else to read them in the letter.
Tears and emotion were rare with him, and leave us room
enough for speculating on what might have been the inner
romance of that life which externally seemed so simple and
so contented with matters of fact.

His attention to ladies, and his great respect for their
mental attainments, makes us still more inclined to refer to
awkwardness of manner, the appearance of " repulsiveness
and harshness," words that seem out of place when used in
speaking of one so little disposed to oiFend.

The answer to his friend Mr. Gough, who attacked him on
the subject of the atmosphere, shows great forbearance and
innate nobleness of feeling, under circumstances in which
every thing that is most bitter and severe is generally ad-
mitted to pardon.

In a town like Manchester, where exertions to extend the

HISTORY OF THE ATOMIC THEORY. 71

material portion of civilization take the form in the minds of
most men of a struggle for wealth, in which the original object
is forgotten, it is a proof of simplicity and singleness of
character when we find that he was never once led away by
the glare of the princely fortunes around him. He gave
lessons for very small fees, from Is. 6d. to 28. 6d. a lesson.
He made analyses, and was consulted by manufacturers, pro-
bably the earliest in the district of that class of scientific men
called ** professional chemists" who have risen as a necessity of
the time, and by private establishments have made some com-
pensation for the lack of public institutions and professorships,
in some countries so abundant, and have chiefly in their hands
the connexion of the chemical arts with the science as it pro-
gresses.

Dalton's character as a man is then easy to understand ; he
was a simple inquirer into nature, his enthusiasm rose only in
her presence, his life was devoted to her study. Abstracted
in a great measure from the world in its social relations, he was
sufficiently connected with it to have endeared himself to all
those with whom he lived, and to have formed with some of
his contemporaries the warmest friendships. The friends of his
childhood were never forgotten, but more warmly remembered
as he grew older ; whilst he did not the less remember those
that he learnt to know only since his manhood. Gentle at least
in his spirit, his very solitary life and abstract mode of thinking
had not allowed him time to modulate his voice to suit the
ears of those accustomed to more polished society, and a cer-
tain rigidity of body, as well as of mind, caused the movements
of both to have the appearance more of power than of grace.
He was simple, temperate, and regular in his habits, never
carried away by the feelings of the moment to indulge in
luxuries to which he was unaccustomed, in all his actions
avoiding excess, yielding to order and regularity as the only
master passion which had power to carry him beyond what we
may consider the just bounds of reason.

72 MEMOIE OF DR. DALTON, AND

Although unwilling to offend, he was accustomed sometimes
to give severe rebukes to ignorance when it pretended to
know, and in this capacity alone do we find him ever creating
a feeling of opposition in those who surrounded him, although
even this was seldom, and only on great provocations, and
chiefly in his character as President of the Philosophical
Society, where the exercise of wise authority was expected
and desired. Local memory tells us of several severe, but
well deserved and not ill-natured rebukes.

In a life of labor, of experiments with weights and with
numbers, it is seldom that the imagination flourishes, and so
we find that literature was entirely neglected, and his own
discoveries have not been illuminated by the radiance which
it is in the power of some men to shed around the creations
of their mind, but have been sent out dry and hard into the
world to gather as they best might the life which he was
certain of obtaining for them.

In this is the secret of many varying opinions about Dalton ;
this is the secret of his want of success in early life, of his
remaining so long apart from scientific men, and of the dis-
putes as to his originality. The "genial current of the soul"
had been constitutionally stopped, and words were wanting to
express his feeling, which at last seemed not even to struggle
for utterance. He gave us knowledge, mere knowledge does
not give life until it is become a familiar inmate of the mind,
until we can see it in all or many of its aspects, until it
becomes an object on which we delight to gaze, and seeing
its beauty begin to surround it with results from the imagina-
tion. He that can do this, putting the results of science into
a poetic form, and impressing them upon the mind, receives
often more admiration than the originator, the exertions of
whose whole life may probably be summed up in a sentence,
and seen at a glance by the popular eye; but experience
proves that the original work requires a persistance of efibrt
and a clearness of conception, which are very rarely united.

HISTORY OF THE ATOMIC THEORY. 73

True, Davy and Dumas add poetry and eloquence to
sterling" scientific vigour, whilst in Dalton we find only
strength and rude simplicity ; the glowing radiance which
dazzles us in the writings, and even in the characters of
some men, is wanting in him; but strength and simplicity
are rare and valuable gifts, although we must look to their
combination with beauty in its widest sense for the very
highest standard of mankind.

74 MEMOIR OF DR. DALTON, AND

CHAPTER IV.

HISTORY OF THE ATOMIC THEORY.

IDEAS OF MATTER UP TO THE TIME OF LUCRETIUS.

There is no chapter in the history of man more marvellous
than that which deals with his conception of matter.
There has been the greatest difficulty in all ages in com-
prehending its existence, and still more so in conceiving
how it can be constituted of so many different substances. It
seems, beyond expression, strange, that although himself
made of matter, and exposed so frequently to the pain
of living in regions covered with most inhospitable forms
of it, or tossed about in an unmanageable ocean of the
same, he should still for a long lime confuse the conception
of it with spiritual existence, and still longer fail to obtain
any distinct idea of the cause of their diversity. I do not
allude only to the metaphysical difficulties even now unsolved
as to the existence of matter, but to those perhaps most
apparent in the history of the physical sciences. The diffi-
culties have begun with the savage who scarcely distinguishes
the wood from his divinity, and still less divides substances
into classes. They are difficulties which, in one form or
other, have struggled long in man, and the progress of which
may be seen perhaps most clearly in the Greek, but more or
less in all nations who have thought on philosophical subjects,
whilst the struggle in Europe in the middle ages was long
and violent, occupying the most active minds of the age. It
is strange to observe the pertinacity of man in deciding that
matter is one, that all substances have the same substratum

HISTOBT OF THE ATOMIC THEORY. 75

without distinct facts as a proof, but relying on his reasoning
powers alone; deciding that fire, air, earth, and water, are
the same, although burnt out of his house by one, and
drowned by the other, and to obtain a third, risking everything
that he possesses. He has with difficulty been able to think
of the facts before him, except under the influence of some
previous conclusion, and pressed to the earth as he has been
by physical difficulties, as well as by sensuality, he has con-
tinually clothed it with immateriality. Sometimes he appears
as a spiritual being, from some higher state of his metempsy-
chosis, with difficulty treating conceptions new to him about
mere material things, or perhaps more like a material being
oppressed with weakness of conception, grasping at more than
he can understand, he has failed to see clearly the facts that
of all others seem to stand most prominent before him.

The idea of matter representing the present stratum of
knowledge obtained from experiment, and which chemists
so long entirely missed, is, that there exist bodies which we
cannot divide and call simple, that these by union among them-
selves form other bodies; that when united the original bodies
are by no means lost, and may be again separated without
losing any of their original indestructible properties. This
statement is a simple relation of facts. These bodies may
be farther divisible ; they may be, and probably are, all con-
vertible into one, but when we trace them further than our
experiments warrant us, we go back to the position of the
Greeks, who have already said nearly all that the mind
seems able to attain to, unassisted by the study of nature.
Indeed, this idea cannot be said to be in any way new,
but one of the very oldest, although frequently lost, to be
seen at intervals in fragments, but not until within the
memory of man to obtain permanent ground in science:
although inevitably doomed to prove only a portion of the
truth, it is no less true in its own limits. So simple is the
idea, requiring too such enormous labour and long time to

76 MEMOIR OF DR. DALTON, AND .

obtain, that it makes us readily believe that we may now
be living under the grossest delusions which a little spark
of genius might readily dispel, revealing to us a world entirely
different to that which we are accustomed to see ; and without
a doubt this is to a great extent the case.

As an instance of the diflSculty of arriving at a rational con-
ception of material phenomena, but more especially in order
to give a sketch of the history of the subject, I shall adduce
the opinions shortly expressed of some of the most prominent
thinkers of ancient times.

Much as has been written on this ancient part of philoso-
phical history, a full as well as distinct account is still wanting.
Most writers give us so much explanation, that we cannot
understand them : the collected fragments would form a
valuable volume. The physical has generally been given
as a mere appendage to the metaphysical history.

Although the earliest opinions relate more directly to crea-
tion or cosmogony than to the nature of combinations, they
still are interesting in connection with our subject, as they
show us the early methods of viewing matter, and illustrate
the difficulties as well as progress of the subject. Of the
early Greek schools, where fragments only exist, I shall
give a few particulars taken chiefly from Ritter and Tiede-
mann, not giving the original words of the ancient authors,
some of which have been lost, and others greatly scattered.*

Thales considered the earth to be a living being, and
the only primitive princij)le from which all things are
formed to be water. He observed, no doubt, that where
there is no water, there is no growth of vegetable or animal
life. The vegetables are fed by the rain ; they contain water
in their juices, or they do not live. Animals dried up are
dead. Life goes on in the world only with water, even the

• Ritter's '• Geschichte der Philosophie." I used the French edition.
Tiedemann's " Geist der Spekulativen Philosophie."

HISTORY OF THE ATOMIC THEORY. 77

land grows from it, the islands lift their heads out of water,
and the continents repose on great waters.

The rising of the world from oceans was a theme in the
still earlier cosmogonies of the east.

If all the solid things spring from water, and if water may
pass into air as it seems to do in evaporating, then all things
spring from water.

This idea is scarcely dead. Van Helmont believed he
proved by experiment that plants grow from water, and
without correct analyses, we should be obliged to decide in
the same way.

Anaximenes believed the principle of all things to be found
in the boundless air. We may reason thus with him, partly in
his own words, and partly in ours. The world is limited, the
land and water have a definite termination, the air alone is
boundless. The air sometimes condenses from itself fierce
winds, black clouds, rain, snow, and solid hail; these again are
found on the earth as water, and are found to contain the solid
world, and although this may rest in the water, the water itself
rests in the infinite expanse of air. We breathe air, and live by
doing so; when we cease, life ceases; the life and soul are air,
which becomes in this way, not only the spirit which moves
all things, but the source from which all things are produced,
a living principle to the world as a whole, as well as to us.*
" He believed in four principle degrees in the qualities of air,
which responded to the common opinions of four elements ;
from these degrees, fire, air, water, and earth, were formed all
the other properties of natural things.**t

Diogenes, of Apollonia, believed also in " air being the origin
of all things, but requires a greater variety of this element.
For one is not the same as the other, for there are many
varieties of air and many considerations; some is warmer,
some colder, some drier, some moister, some calmer, some

• Ritler, Vol. I., p. 182. f Page ^W-

78 MEMOIR OF DR. DALTON, AND

more agitated, and it has many other alterations, caused both
by its qualities and its substance ; and the soul of all living
things is air," &c. The air penetrates everywhere, it must be
endued with intelligence, as all things are disposed with con-
summate wisdom. The differences in the sensible qualities of
things are referred to condensation and expansion.

To prove that all things are one. " It appears that all
that exists is merely the change of one and the same thing ;
and this is evident, that if all that is in the world, the earth
and water, and other things, were different, and made essen-
tial changes, there could be no transformations among
things."* This is correct reasoning, if we were convinced
of transformations, and we must remember that without
analysis, we must believe in such changes, as the plant seems
to be transformed from water or earth. This reasoning
marked a necessary step in the progress of chemistry.

We see here that properties have to be given to air in order
to account for its diversities. These properties, among the
most important, heat, are not clearly defined. The earth is
precipitated from the air by condensation, but there is no
explanation of condensation, so that after reasoning on these
few principles, the simple atmospheric air which formed the
commencement becomes something else, and a mystic air,
a kind of substratum of air, is in reality what seems to be
signified, as no common air could contain all the properties
required. The same is wanted with water, which, after a
while, has too much given it to do, to be only common water,
and we find the very same thing occur with the rest of the
four elements, as well as with the three alchemistic elements.

The soul of all things producing such admirable order, as
Diogenes perceived, " it is astonishing that this doctrine did
not conduct to the distinction of mind and matter, and that
he conceived the principle of all things, even intellectual

* Page 188.

HISTORY OF THE ATOMIC THEORY. 79

phenomena themselves, to be material." * — Ritter. But how-
ever this may be, it is not less astonishing than very much later
opinions which distinctly gave material form to ideas. Diogenes
was the last of this class who conceived the world to be a
living thing, in a narrow sense, and each individual as for a
time only able to live isolated, and to resist the influence of
the external and greater life which in the end enveloped all.

We have seen air and matter made the flrst principles, and
now we find Heraclitus, of Ephesus, fixing on fire, which before
had been made to play an important part as heat, expanding
or contracting all things. In the absence of any full exposi-
tion of his reasoning, let us rather attempt, as with the others,
to complete it for ourselves. He seems to have thought that
wherever there is warmth there is life, where heat comes there
is motion and activity, it is the principle moving all things, a
secret fire which gives life to all things, it produces air, as we
see it constantly do when substances burn. Air again pro-
duces other elements. As fire produces air, so fire converts
water into air, and heat causes those changes in the atmos-
phere which produce water, whilst by its action on the earth
it produces land also, which is raised from the sea. As all
things have preceded fire, so in the end must fire swallow up
all things or all things will return to it. " The harmony of
the world arises from contrary forces, as that of the lyre and
the bow."t " The finest harmony is produced by opposites,
and every thing is produced by strife." But as with the others,
so with Heraclitus, fire was not common flame, but gradually
became an expression of force, and we still use the word in
this more spiritual sense.

In Anaximander, of Miletus, we find the elements operated
on, and transformed by a power which he calls " the infinite,"
and the higher forces are gradually developed out of the
lower. This, although an interesting chapter in the pro-

• Page 190. t Page 214.

80 MEMOIR OF DR. DALTON, AND

gressive theory, which is probably the oldest of all theories, is
not sufficiently related to the chemical characters of bodies.

After finding force and intelligence given to matter, we find
Pythagoras going to quite the opposite extreme, and making,
to all appearance, the origin of all things to be in numbers.
Tiedemann says, " In these early days of philosophy, the
abstract was not separate from the concrete, there were,
it is true, different names for them, but the different meanings
were not distinct.* Pythagoras took his abstract and general
ideas of objects for the objects themselves, and converted
general ideas into substances." Although the Pythagoreans
gave much of the work of the world to fire, they had no
distinct ideas on the elements.! In harmony with this kind
of reasoning, they produced everything from points which
seem to have been mathematical, and again, all things were
produced from God, because they were produced from
numbers, the first of which is "one." J This one is the
highest God, and of Him our minds are portions.

It is a question whether we can even now in all stages
separate the concrete from the abstract. The principle
of the Pythagoreans is in reality a pure dynamical theory
of matter where there are mathematical points and surfaces
forming the limit of bodies. " All things are composed of
points or unities of space which form together a number."
The use of the word number introduces a difficulty into
the conception of the subject, but leads us at once to the
conception of force, whatever may be its origin. Their
love of music led them to infuse harmony into all nature,
and their love of mathematics led them to see in it
order and numerical arrangement. They gave the highest
place to one ; they attached particular virtues to the small
numbers up to five, apparently for mathematical reasons;
they admired seven as the origin of seven chords and planets;

•Tiedemann, Vol. I., p. 96. f Page 97. % Ritter, Vol. I., p. 325.

HISTORY OF THE ATOMIC THEORY. 8 1

and ten the number of elementary qualities and their con-
traries.

On applying these numbers to matter and to calculation,
we see no inclination to enter into details and to explain the
constitution of different bodies by such means. Or, in other
words, the numbers of Pythagoras are not of such a cha-
racter as to give us the slightest clue either to the atomic
theory or that of equivalents, although the remnants of his
philosophy shew that he must have greatly exalted the mode
of thinking wherever he taught, and led men to seek law
and science or great and beautiful truths in the study of
nature.

He believed in five elements. This spiritual method of
derivation, or explanation, is at least an interesting instance
of that mode of thought. Numbers being the origin, the
monad, is a point ; the dyad (or dual), is a line ; the triad, is
a surface ; the tetrade, a geometrical body ; the pentade, the
physical body with sensible properties. The cube, was the
earth ; the pyramid, fire ; the octahedron, air ; the icosahe-
dron, water ; the dodecahedron, the fifth element, Aristotle's
ether.

This is enough from the many contradictory notices about
Pythagoras, it leads to a pantheistic view of creation, and is
another feature in the progress of the subject.* The Pytha- '
goreans spoke chiefly of morals ; of nineteen writers, whose
fragments I consulted, none spoke of physics.

Anaxagoras says, "The Greeks are wrong in thinking that
some things are produced and others perish, for nothing is
produced, and nothing perishes ; but some things are mixed,
some separated, some confused, some distinct, and production
or perishing may be properly called composition or mixture,
and decomposition or separation."

" The number of things remains always the same." He

• Tiedemann, Vol. L, p. 118.

M

82 MEMOIR OF DR. D ALTON, AND

conceives all the elements to have existed in infinitely small
parts. " All things were together, infinite in number and in
smallness,* and this smallness was infinite, and all being
together, nothing was distinct because of its smallness." All
was put in motion by a mind which governed all, and the
elements attained differences of character by the preponder-
ance of one or other. The small particles are in constant
motion. There are of these particles endless numbers of
every character ; so a piece of gold consists of endless pieces
of gold, so also silver, copper, blood, bones, flesh, water,
fire, and earth, consist of infinitely small portions of these
substances.f To effect this he adds, that everything was
found in everything, because, as the animal grows from its
food, the parts of the animal must be contained in its food.
A kind of reasoning which, in one sense, is undeniable, but
no proper account is taken of the formation of compound
bodies, although his ideas of mixed and simple elements
might have been supposed to lead him to this mode of reason-
ing, without the invention of homoiomereia (or homeomeria),
the name given to this notion of every body being formed of
particles like to it.

In this we find a want of discrimination in separating
metals from organic substances, the changes of which seem
much more allied to transformations, but we find in him
philosophy obtaining a view of mind and matter as distinct,
and the existence of a ruling power, God, introduced into
science. But even here there was some difficulty in obtain-
ing an idea of power without matter, and that is made like
an ether, which, however, has an undefined meaning, although
it seems generally to refer to a more refined kind of air,
expanded into force and intelligence.

It is by no means intended to expound the various philo-
sophies of the ancients, and so from Parmenides we can only

• Tiedemann, p. 251. f Page 1316.

HISTORY OF THE ATOMIC THEORY. 83

find two ideas exactly suiting the subject. First, all is one.
There is only one existence, and there is nothing but existence.
Secondly, thought is completeness. Here we may then say
that we have got an opinion different from the preceding, in
which physical forces have no independent place, although
some of the expressions of this philosopher would lead to
believe that he considered the earth as the origin of all
things, acted on by fire.

Zeno, of Elea, had four elements, warm and cold, moist
and dry, corresponding to the four ordinary elements, with
necessity as a moving force regulating all; concord and
discord (attraction and repulsion) were some of its manifes-
tations; but in reality nothing existed. We have then, one
after another, a play on every one of the elements, each
elevated in its turn, diminished to one or to a mere idea,
or increased to an endless extent, where idea is only the
action of an element.

Empedocles gives more distinct form to the four elements, at
the same time elevating them by the name of gods. With him
they are eternal, and consisting of minute parts, which although
divisible, are never divided. This is an early approach to our
present chemical theory of a diversity of elements, not trans-
mutable. The principal place is given to fire. But the Jour
were upheld logically, when he said they were never dinded ;
but he afterwards adds that they were in reality only two.
By him a new phase of character was given to the elements,
for he says " our souls consist of all four elements, and
every element is itself a soul."* " Life can only be known
by life ; for by the earth we know the earth, by the water
the water, the divine air by the air, the devouring fire by
fire, love by love only, and strife by direful strife." f The
principle of love (^iXm) he held to be the origin of the
elements, and the cause of their unions ; the opposite prin-

• Tiedemann, Vol. I., p. 253. f Quoted by Rilter, Vol. I., p. 454.

84 MEMOIR OF DR. DALTON, AND

ciple {vEiKog) discord, acting with it, produced the various
changes. We have here attraction and repulsion in their
early days; but it is also said by him rather curiously,
" discord decomposes the mixtures of the elements, and mixes
fire with fire, air with air, each sort of element with its like,
whilst concord acts on the contraries,"* as now found with
electric -\r and — poles.

Leucippus first distinctly gave a meaning to the notion of
small particles of bodies, which he called atoms. Democritus
held the same opinions. Everything is composed of indivisi-
ble atoms. They could not be divisible, neither could they
be mere points. They have neither colour, taste, smell, heat,
nor cold : all these properties are given them by their various
mixtures: there are various shapes. The first impulse to
motion was given probably by an original force.

This is the real meaning of all he said ; everything was
referred to atoms, even the soul or mind itself. This is a
point of great importance in the history of our knowledge of
matter, and one beyond which we have not yet got in
some of its relations. Here then we stand and are obliged
to review our speculations and inquiries in some respect
from the standing point of Leucippus and Democritus.
In this view we have a distinct idea attached to the com-
position of bodies, and although one which might have
readily come into the mind of any one who thought clearly on
the subject, yet we are not aware of the difficulties attending
the production of ideas, viewing them after they have been
overcome. Democritus arrived at the idea of distinct atoms
forming matter of every kind by the change of position.
Anaxagoras was nearly at this point, but he gave the atoms
characters exactly like the compound object. Democritus
gives the simple bodies only shape, extension, and force.

Plato taught that the world was created by an intelligent

• Ritter, Vol. I., p. 445.

HISTORY OP THE ATOMIC THEORY. 85

cause, and did not exist from eternity, and that it has passed
from order to disorder, because order is better than disorder.
God also has endowed the world with reason, it is an animated
being, and not to be destroyed, but by him who made it ;
but he will not destroy it, as the good cannot destroy what is
beautifully fitted. The world moves by its own life. The
elements seem to Plato, to be only forms under which matter
exists, and are convertible one into the other. The five
forms of matter serve as a base to determine the elementary
forms, the pyramid corresponds to fire, the cube to earth,
the octahedron to air, the icosahedron to water, whilst the
dodecahedron, like the sphere, comprehends like the earth,
all the elements.

These are the expressions of Ritter, but on looking into
the original it is not found exactly so, although the mode of
reasoning somewhat justifies it. The words are ^^tartj ^1,
Kara rov op3^ov Xoyov icai Kara tov liKOTa, to fjilv Trig irvpaiJ.idoc
(TTtpwv ytyovog i'l^og, irvpog (TTOi)(iiov kcli (nrtpiuia,*' &c., as in
the translation of Davies. " Let it be agreed then that
according both to strict probable reasoning the solid form of
pyramid is the element and germ of fire," &c. ; another way
of expressing matter dynamically.

In the Timaeus he says, " First, then, that fire and earth,
water and air, are bodies, is evident. * * * * }^q
must relate, then, of what kind these most beautiful bodies
were that thus came into being, and which, however unlike
each other, may yet be produced from each other by disso-
lution. By accomplishing this we shall ascertain the truth
about the generation of earth and fire, as well as those ele-
ments (water and air) which hold an intermediate position,
for then we shall allow no one to assert that there are visible
bodies more beautiful than these, each of which belongs to a
separate class." But this does not seem to have been held
firmly, because he says also at 51 Timseus, ** Our plastic
Creator, reflecting on all this, then mingled and united

86 MEMOIR OF DR. DALTON, AND

matter, fire, and earth, gradually mixing therewith a ferment
of acid and salt (e? ojcoc kqX aXfxvpov), and thus he composed
a soft pulpy flesh."

As to the composition of the elements, as all was created
from mind, the separation of mind and matter does not seem
clear. Although he says, also, " It is evident to every one
that fire, air, water, and earth are elements, but every species
of body possesses solidity, and every solid must necessarily be
contained by planes. Again, a base formed of a perfectly
plane surface is composed from triangles. But all triangles
are originally of two kinds, each of them having one angle,
a right angle, and the two others acute, and one of these has
an equal part of a right angle, divided by the equal sides,
while in the other, two unequal parts of the right angle, are
divided by the unequal sides. This, then, we lay down accord-
ing both to probability and necessity, as the origin and principle
of fire and all other bodies; but as for the heavenly principles
thereof, those indeed are known only to the Deity, and to those
among men who enjoy God's favour."* One might suppose
he was speaking of the shape of the elements, and we see the
want of definiteness in the forms of conception of the physical
elements. Again, matter so far as it is only matter must be
viewed abstractedly from all qualities; qualities are deter-
minate conditions of matter. The motions of matter are
without rule, purpose, or harmony; purpose, order, and
harmony are only to be obtained from the reason.f Physics
was in reality the region of uncertainty, whilst true science
was in the reason : we have in modern times adopted a
different opinion. This will probably be enough to enable
us to find the class to which Plato belongs, as regards our
subject. By going much further we get into metaphysics,
or perhaps worse, into contradictions.

• Timaeus, par. 28.
t Tennemann. System der Platonischen Philosophie. Vol. III., pp. 30-152.

HISTORY OF THE ATOMIC THEORY. 87

In looking on physical nature, as far as our object is con-
cerned, little is got in Aristotle, the idea of which did not
exist elsewhere. His first form of substance, which is per-
ceptible to the senses, is finite and perishable ; he uses the
ordinary four elements. There is a fifth element preceding
the four elements, with a tendency neither above nor below ;
this is ether. The heaven is made of it, and never changes.
The four elements seem to be substance united to the warm,
the cold, the light, and the heavy.* He more clearly brought
forward existing theories, expressing his own with greater care,
and giving a history of others.

The varying phases of matter and of force shewed them-
selves in after philosophies. Matter rose and fell, mind rose
and fell. Matter was mind, mind was matter, and even at
this period we see no such nice distinction between them
among the ancients as we now have, whatever be the founda-
tion of our opinions.

The stoics said, that " matter (that is ; considered in itself
without quality and form) did not exist except under a
certain form, and with certain properties. It is the principle
of every thing which springs from it, and consequently is
variable. Being absolutely passive it is infinitely divisible as
body is."t But these opinions would lead into grounds too
little physical.

The stoics retained the four elements which lasted so long in
science, and believed that fire was condensed into air, air into
water, water into earth. They called matter a collection of
dimensions, length, breadth and thickness, leaving out solidity,
so that matter became penetrable.^ Only matter can do any
thing. This led to the wildest assertions, that laughing,
dancing, walking, crying, as well as emotions, anger, joy,
fear and passions, avarice, pride and envy, vices and virtues,
day, night, and sound, were bodies. This was carrying

• Tiedemann, Vol. II , p. 284. f Ritter, p. 479. t Tiedemano, p. 434.

88 MEMOIR OF DR. DALTON, AND

out their general principle to the utmost, and, of course,
leads to an entire want of definition of natural things.
Knowledge is gained by observing qualities, not by con-
founding them ; by seeing distinctions, not by hiding them.
The most contradictory assertions of all kinds have been
made on the subject, especially after the great masters had
done their utmost services. We must not suppose the above
to be merely ridiculous. It evidently involves an extension
of the idea of body, the limits of which are still unknown,
and in some form or other it has often risen, and is likely
again to rise, for discussion.

We find that ir. nearly all the cases alluded to matter has
been able to put on various forms, and that it is of itself
a mere abstraction. There is, in nearly all, a substratum
more or less decidedly expressed. That is, a matter without
properties to the senses, but capable of putting on all. The
mater^ mother of all substances. With this idea before us,
most of the opinions will have some connection and ration-
ality. Among those who denied the existence of the reality
in the things perceived by the senses, we can find very little
directly relating to the subject; but we must ever view with
admiration and gratitude the acute minds which have done so
much of the preliminary work necessary both for physics and
philosophy.

The atomic system of the ancients was most fully ex-
plained by Lucretius, and leaving the nice distinctions of the
stoics, and their semi-metaphysical modes of looking on
matter, let us look more fully at this system than the others,
as it may be said to form the beginning of the atomic theory,
although the short and meagre introduction preceding may
not be without interest to such as have not had time to read
of the struggles of the mind in early times towards a rational
oxpression of phenomena. It was a struggle of the most
gifted minds in some of the most brilliant days of the world.

HISTORY OP THE ATOMIC THEOBY. 89

and will never cease to be an interesting chapter in man's
history.

The more distinct conceptions of matter introduced by
Leucippus, and promulgated by Democritus, were adopted by
Epicurus, and have often gone by his name. If not ultimately
the most exact, they have in many respects a practical truth,
and they have the merit of having the main features clearly
intelligible. The system was gaining ground at a time
when the Alexandrian school was saying that matter
which can be perceived emanates from the soul,* and that
bodies were convertible into each other because made of one
matter, which original matter had no qualities, and was capable
of taking all.f This was very much in the manner of their
predecessors, except that we recognise in it an increase of
mysticism in their expressions. This substratum of matter
has bewildered whole tribes of philosophers.

Lucretius is in the hands of every one, but read by few.
The following portion on atoms is from the translation of the
Rev. J. S. Watson (Bohn), with little alteration: —

" Nothing can do or suffer without bodily substance, nor, more-
over, afford place (t. e.y for acting and sufferinp) except empty and
vacant space. No third nature, therefore, (distinct) in itself, besides
vacant space and material substance, can possibly be left in the sum
of things ; no third kind of being, which can at any time afiect our
senses, or which any one can find out by the exercise of his reason.}
♦ • ♦ * ♦ Bodies are partly original elements of things, and
partly those which are formed of a combination of those elements.
But those which are elements of things no force can break, for they
successfully resist all force by solidity of substance; although,
perhaps, it seems difficult to believe that anything of so solid a
substance can be found in nature: for the lightning of heaven
passes through Die walls of houses, as also noises and voices pass ;

• Ritter, Vol. IV., p. 488.
t Tiedemann, Vol. III., p. 295. See also Histoire de Tecole d'Alezandrie,
par M. Jules Simon. No short sentence can give the exact truth.
X Book I., 1. 444-449.

N

90 MEMOIR OF DR. DALTON, AND

iron glows in the fire ; rocks often burst with fervent heat ; the
hardness of gold, losing its firmness, is often dissolved by heat ;
the icy coldness of brass, overcome by flame, melts ; heat and pene-
trable cold enter into silver, for we Kave felt both with our hand,
when, as we held cups straight in the hand, water was poured
into them from above, so that as far as these instances go there is
nothing solid in nature. But because, however, right, reason, and
the nature of things, compel (me to hold a different opinion,) grant
me your attention until I make it plain in a few verses, that there
really exist such bodies as are of a solid and eternal corporeal
substance, which bodies we prove to be seeds and primary particles
of things, of which the whole generated universe now consists."

" In the first place, since a two-fold nature of two things ex-
tremely dissimilar has been found to exist, viz., matter and space, in
which everything is done, it must necessarily be that which exists
by itself for itself, and pure (free from mixture) ; for wheresoever
there is empty space, which we call a vacuum, there is no matter ;
and likewise wheresoever matter maintains itself, there by no means
exists empty space. Original substances are therefore solid, and
without vacuity.

" Furthermore, since in things that are produced there is empty
space, solid matter must exist around it ; nor can anything be proved
by just argument to conceal vacuity, and to contain it within its
body, unless we admit that which contains it to be a solid. But
that solid can be nothing but a combination of matter, such as may
have the power of keeping a vacuity enclosed. Matter, therefore,
which consists of solid body may be eternal, while other substances
may be dissolved (or cease to be). In addition, too, if there were
no space to be vacant and unoccupied all would be solid. On the
other hand, unless there were certain bodies to fill up completely the
spaces which they occupy, all space which exists must be an empty
word. Body, therefore, is evidently distinct from empty space.

'* These bodies (which thus fill up empty space) can neither be
broken in pieces by being struck with bodies externally, nor again
can be decomposed by being penetrated internally ; nor can they be
made to yield, if attempted, by any other method, which we have
demonstrated to you a little above ; for neither does it seem possible

HISTORY OF THE ATOMIC THEORY. 91

for anything to be clashed in pieces without a vacuum, nor to be
broken, nor to be divided in two, by cutting ; nor to admit moisture,
nor moreover subtle cold, nor penetrating fire, by which all things
are dissolved ; and the more anything contains empty space within
it, the more it yields when thoroughly tried by these means. If,
therefore, the primary atoms are solid and without void, they must
of necessity be eternal.

" Again, unless there had been eternal matter, all things before
this time would have been utterly reduced to nothing, and whatsoever
we behold would be a reproduction from nothing. But since I have
shown above that nothing can be produced from nothing, and that
that which has been produced can not be resolved into nothing, the
primary elements must be a of an imperishable substance, into which
every body may be dissolved, so that matter may be supplied for the
reproduction of things, The primordial elements therefore are of
pure solidity, nor could they otherwise, preserved as they have been
for ages, repair things through the infinite space of time.

** Besides, if nature had set no limit to the destruction of things,
the particles of matter would by this time have been so reduced,
every former age wasting them, that no body compounded of them
could, from any certain time, reach full maturity of existence. For
we see that anything may be sooner broken to pieces than put to-
gether again ; for which reason, that which the infinitely long dura-
tion of past time had broken into parts, disturbing and dissevering it,
could never be repaired in time to come. But now, as is evident,
there remains appointed a certain limit to destruction, since we see
every thing recruited, and stated portions of time assigned to every
thing according to its kind, in which it may be able to attain full
vigour of age.

" To this is added, that although the primary particles of matter
are perfectly solid, yet that all things which are formed of them,
may be rendered soft, as air, water, earth, fire, because there is
vacant space intermingled with the things compounded. But, on the
other hand, if the primordial elements were soft, how strong flints and
iron could be produced, no explanation could be given, for nature
would be deprived of all possibility of commencing a foundation.
The primordial elements therefore are endowed with pure solidity ;

92 MEMOIR OF DR. DALTON, AND

by the dense combination of which all compound bodies may be
closely compacted, and exhibit powerful strength.* Moreover,
if no limit has been appointed to the dissolution of bodies, there
must remain certain bodies in the world which have not yet been
assailed with any trial of their strength. But since (dissoluble
bodies) are endued with a fragile nature, it is inconsistent to suppose
that they could have lasted through an infinite course of time, harassed
age after age with innumerable assaults.| * * ♦ »

" Primordial atoms are therefore of pure solidity, which, composed
of the smallest points, closely cohere, not combined of a union of any
other things, but rather endowed with an eternal, simple existence,
from which nature allows nothing to be broken off, or even diminished,
reserving them as seeds for her productions.

"Moreover, unless there be some /ea*^, the smallest bodies will,
individually, consist of infinite parts.J * * * * What therefore
will be the difference between the greatest and smallest of bodies ?
It will not be possible that there should be any difference ; for though
the whole entire sum of things be infinite, yet the smallest things
which exist will equally consist of infinite parts. 1|

ic * * * * * Those who think that fire is the original prin-
ciple of things, and that the universe is maintained from fire alone,
do greatly err from true reason ; of which Heraclitus, as leader, first
comes to the battle, celebrated for the obscurity of his language.

* * * * YoT fools rather delight in all things which they see
hid under inversions of words. * * *

"For how, I ask, could things be so various if they were produced
from fire alone and pure (from mixture)? Since it would be to no
purpose that hot fire should be condensed or rarefied, if the parts of
fire retained the same nature which the whole of the fire still has ?

* # * * gy^ jf ^Y^^y think that fire may by any means be extin-
guished in condensation, and change its natural consistence, and if
they shall not hesitate to allow that this may take place absolutely,
then all heat, it is evident, will fall utterly to nothing, and whatever
things are reproduced, will be made out of nothing. For whatever
departs from its own limits, this straightway is the death of that

* 1. 484-677. t Not in my copy of original. % 1. 603-610.
II 1. 613-616.

HISTORY OF THE ATOMIC THEORY. 93

which was before. Something, therefore, must necessarily remain
unchanged in that fire of theirs, that all things as you see, may
not utterly fall to nothing, and that the multitude of objects in
the universe may not have to flourish by being reproduced from
nothing.*

f " It would be to no purpose that some (of these elements) should
detach themselves and depart, and be assigned to another place, and
that some should have their order changed, if they all still retained
the nature of fire, for whatever (fire) should produce would be in all
forms only fire. But, as I think, it stands thus : — There are certain
elementary bodies, whose combinations, movements, order, position,
shapes, produce fire, and which, when their order is changed, change
their nature ; nor, as I think, are they like to fire, or to any other
thing, which has the power of emitting particles to our senses, and
aflfecting our touch by its application.

J " Wherefore those who have thought that fire is the primary
matter of all things, and that the whole universe may originate from
fire ; and those who have determined that air is the first principle
for the production of things; those who have imagined that water can
itself form things of itself, and that the earth produces all things, and
is changed into all substances of things, appear all to have wandered
extremely far from the truth.

" Also those who couple the elements of things, uniting air with
fire, and earth with water, and who think that from these four things
all bodies proceed. * * * * § Moreover, if all things were
produced from these four bodies, and all things dissolved into these
bodies, how can these be called the primary elements of things, rather
than, on the other hand, things (called the elements) of them, and
a backward computation be made ?

II And now let us examine the ofioiofiepeia (homeomeria), as the
Greeks call it, of Anaxagoras, nor does the poverty of our native
tongue allow us to name it in our own language. * * * He
thinks that bones are produced from small and minute bones. So
likewise flesh is generated from small and minute particles of flesh,
and so on.

• 1. 636-676 t 1- 681. % 1. 706. § 1. 764. | 1. 830.

94 MEMOIR OF DR. DALTON, AND

* Moreover, since food augments and nourishes

the body, we may understand that veins and blood, and bones, and
nerves consist of heterogeneous parts. Or if they shall say, that all
food IS of a mixed substance, and contains in itself small elements of
nerves and bones, and also veins and particles of blood, it will follow
that both all solid food, and liquid itself, must be thought to consist
of such heterogeneous matter, and be mixed up of bones and nerves,
and veins and blood. Besides, if whatever bodies grow from the
earth are previously in the earth, earth must consist of all these
heterogeneous matters which spring from the earth."

He gets however into a similar difficulty, by saying that
the atoms which make up these substances, have primary
particles of a different figure.

* " Finally, if you think that whatever things you see in the visible
world, could not have been formed without supposing the primary
particles of matter to be endowed, with a nature similar to the things
formed from them, your original elements of things by this hypothesis
fall. For the consequences will be that you must have primary
particles of matter, which, being the origin of laughter, are themselves
convulsed with tremulous fits of laughter, and others which bedew
their own faces and cheeks with salt tears."

As to forces, he says : —

f " For certainly neither the primary elements of things disposed
themselves severally, in their own order by their own counsel or
sagacious understanding; nor assuredly did they agree among
themselves, what motions each should produce ; but because being
many, and changed in many ways, they are for an infinite (space
of time) agitated, being acted upon by forces, throughout the whole,
they thus by experiencing movements, and combinations of every
kind, at length settle into such positions, by which means, this sum
of things produced, exists."

He speaks again of their being moved of themselves, and
urged by secret impulse ; and gives their original motion to
be a falling straight down, not in a right line. For if they

• 1. 914. t 1. 1020.

mSTOBT OF THE ATOMIC THEORT. 95

had fallen in a right line, there " would have been no contact
produced, and no collision generated among the primary
elements."

He gives a limited number of shapes to the atoms, but sees
no need of hooks to keep them together. This variation in
shape leadft also to a variation in size, but the atoms them-
selves are infinitely numerous.

Primordial atoms are not sentient, or they would " produce
nothing but a crowd and multitude of animals."*

So far Lucretius. This theory of the constitution of mate-
rial substances requires us only to conceive of one class of
substances : for although some are larger than others and dif-
ferently shaped, that is not a necessary supposition. It is the
atomic theory properly so called. Forces are as much left out
as possible.

One of the most complete atomic systems seems to have
been produced in Hindostan. There it is said matter consists
of the smallest possible bodies which are indivisible. We must
at last arrive at something limited, otherwise the smallest, as
well as the greatest, would be infinite. The first compound
is binary, the union of two being the simplest, then there is
a formation of three binary atoms, and a new compound of
four quaternary atoms, and so on. The atom is equal in size
to the sixth part of a particle seen by the sun's rays. A
superior force draws the atoms to each other. The union is
not a mere juxta-position, but one drawn by a particular
afl&nity.

This is a peculiar mode of combining the atoms, we have
not three or four simple as we might expect. It is interesting
to find exactly the same course of reasoning about natural
things among the Hindoos as in Greece, although Mill, in his
history of India, ridicules it as the wanderings of the mind ;
the same might be said of the Greek ideas. We find there,

• Book II., 1. 917.

96 MEMOIR OF DR. DALTON, AND

that "from intellect arose fire; from ether, air; from air,
fire and light; from light, a change being effected, comes
water with the quality of taste ; and from water is deposited
earth with the quality of smell." To fire is attributed the
quality of figure : Mr. Mill supposes light is meant ; to air
the quality of touch; to ether the quality of conveying sound.
Mr. Mill thinks hearing is meant. The qualities are con-
fused as in that Greek system, which said, fire only can
understand fire ; air only can understand air ; and so on.*
The Hindoos, also, had their four and their five elements ;
their eternal elements ; and the elements proceeding from the
will of God, to cease when he pleases. They, too, had a
system which made mind a substance and the affections subtle
bodies.f But they did not always confuse it, as is seen in
Menu. " He having willed to produce various beings from
his own divine substance, first with a thought created the
world." On the constitution of matter we see them speaking
as plainly as the Greeks ; and now on the philosophy of the
combination, we see an instance of still greater farsight. We
can readily believe that the following is very beautiful in the
original poetry. There is a poetical beauty even in the prose,
which makes it dance like the power it describes in spite of
the gravity and intellectual nature of the subject.

From the poem of ShiWVn and Ferhad ; or the Divine
Spirit and a Human Soul Disinterestedly Pious.% " There
is a strong propensity which dances through every atom, and
attracts the minutest particle to some peculiar object; search
this universe from its base to its summit, from fire to air, from
water to earth, from all below the moon to all above the
celestial spheres, and thou wilt not find a corpuscle destitute
of that natural attractability; the very point of the first

History of British India. By James Mill, Esq., 1848. Vol II., pp. 94-96.
•f Colebrooke, Asiatic Researches. Vol. IX., &c.
X The Works of Sir William Jones, 1799. Vol. I., pp. 170-171.

HI8T0BT OF THE ATOMIC THEORY. 97

thread, in this apparently entangled skein, is no other than
such a principle of attraction, and all principles besides are
void of a real basis ; from such a propensity arises every
motion perceived in heavenly or in terrestrial bodies ; it b a
disposition to be attracted, which taught hard-steel to rush
from its place and rivet itself on the magnet ; it is the same
disposition, which impels the light straw to attach itself to
the amber ; it is the quality, which gives every substance in
nature a tendency toward another, and an inclination forcibly
directed to a determinate point."

98 MEMOIR OF DR. DALTON, AND

CHAPTER V.

FROM LUCRETIUS TILL THE DECAY OF ALCHEMY.

Egypt seems to have attained to a knowledge of the qualities
of matter never attained in the Greek and Roman empire,
and it is highly probable that a more correct theory existed
in conformity with the more advanced practice. But it con-
cealed its knowledge of science as it concealed its history, and
the treatises which profess an Egyptian origin are more unin-
telligible than hieroglyphics. One is at first inclined to
believe that the mystic mode of writing was simply a result
of ignorance, because when the Alexandrian school begins to
philosophize, it uses language as clear as it is capable of
obtaining, although prevented from great clearness by the
mystic nature of its region of thought. But the results of the
arts exist to tell us that in the region of actual knowledge
they were no triflers, whilst in that of speculation they made
such efforts to gain a knowledge of things superhuman, that
if they have failed it is not for want of devotion, truth, and
energy.

We have seen matter viewed in various aspects according
to the philosophies of the time, and we might almost have
added according to the speculations, viz., those of the popular
beliefs and the mythologies of the time, when substance was
strangely mingled with spirit, and when the gods of the woods
were scarcely separated from the woods themselves. Such a
view is analogous to the ancient Scandinavian method of look-
ing at creation, when they formed the earth from the body of
Ymir, and the sea from his blood.* It shews us that the
intellect does not readily conceive of mind and matter, of

* Prose Edda : Mallet's Northern Antiquities.

HISTORY OF THE ATOMIC THEORY. 99

force and substance, as distinct ; that in fact the early mind
looks on matter in an abstract sense as a thing made of qualities;
which qualities may change indefinitely, and all things easily
be transformable. The elements in this philosophy are not
elements of science, but the common elements of every day
life ; in other words those aggregate objects with which nature
has made the world, without reference to their mechanical or
chemical disunion. In reading the ancient authors, one is
disposed to think that this was the general sense in nearly
every system, and that a strict meaning was not attained by
any one of them, except the atomists. In vain do we quote
their opinions, another quotation comes with a meaning in
exact contradiction, and the vague and indefinite is the only
final result. It is not to be wondered at that this should occur
with the Alexandrian school, which neglected the body,
despised the world, and sought truth only in that state of
mind called ecstasy, which, however exalted it may be, is
very naturally shunned by us as a dangerous forerunner of
the loss of reason, or as a state of hallucination. With them,
there are four elements, it is true, but these are like the
elements of Plato and others, they are convertible, and there
is an abstract matter from which all things are made by the
putting on of various properties. It is the origin of all things
that exist, and has the power of becoming everything, but it
exists only as a power. This leads into metaphysics, which
I avoid; for us, it is enough that they looked on the four
elements as transformable, which have, therefore, not the
character of elements. What are they, then? They are
nothing real, the qualities are changeable, but there are no
data given for finding whence these qualities come, and so we
are led into a region of mere dreams, and nature is a power
playing upon us every imaginable illusion by means of its
forces; "all which forces have their origin in owe, because
unity is the basis of all things." Here, then, being no begin-

100 MEMOIR OF DR. DALTON, AND

ning of matter, properly so called, it is in vain to look for a
beginning of such elements as cannot be convertible, even
if they had not expressly stated that all are capable of trans-
formation.

The early stages of chemistry and metaphysics have uncon-
sciously met. From Alexandria, with its spiritual or mystic
views, the ars sacra^ Uga rcx^*?? came, perhaps carried by
some who had little to teach, at least speaking of matter in
terms too mystical to bear to us any distinct meaning, and
holding their knowledge too sacred to be given to ordinary
mortals.

The spiritual faculty was becoming developed in man. It
had existed before that time in its greatest powers in in-
dividuals, but it had not as yet educated nations. Christianity
had directed man to the consideration of God and the moral
part of our nature with such power and success, that philosophy
was carried away by the current, and at length became entirely
absorbed. But to philosophize on morals and upon spiritual
phenomena, so to speak, is to become mystic, unless great
care be used; and this current of thought induced, acted a long
and important part in the history of the world. The course
of this philosophy, for many ages, seldom led it to touch on
matter with any firmness of step. Man lived in his thoughts,
still fancying himself capable of living independent of mere
external things, his spirit still disinclined to believe in the
great power which the base creations under his feet were
capable of exercising over his finest feelings. There was a
struggle against matter, one which cost thousands of victims,
buried or slain in the ranks of asceticism, or made useless by
the perverted consciences which they carried with them into
common life. Matter was not seriously believed in, it was a
strange power, a thing capable of every action, acted on by
the Deity, or by the spirits of those who either in this world,
or the next, had obtained a share of the primeval influence of
the Creator. With such men there could be no true philosophy

mSTOEY OF THE ATOMIC THEOEY. 101

of matter. This mystic mode of philosophizing had no doubt
been the mode adopted by the chemists of the earliest cen-
turies, but little or nothing now remains. The following is
from Zosimus, the Panopolitan, upon the "Divine water:" —

" The mystery sought is great and divine, for all is from it,
and by it. There are two natures and one substance. The
one carries off and subdues the other. This is silver-water
(mercury), the male-female principle always escaping, con-
stant in its properties, the divine water unknown to the world,
the nature of whiclf is inexplicable. For it is not a metal, nor
is it water ; it is always in movement, nor a body ; it is all in
all ; it has life and spirit, and may be held," *

This is quite in the mystic style of the neoplatonic philo-
sophy, although the tone is evidently lower than that taken
by the philosophical mystics themselves. We see in it clearly
the style of the alchemists, and the impulse that was given to
the study of alchemy seems to have come from this source
mainly. The philosophy of Aristotle having for many ages
taken the lead, the four elements followed him, and we find
them acting an important part in nearly all alchemical treatises,
but the mode of reasoning is by no means Aristotelian, and
is in every sense mystic. And why mystic? This word is
itself of indefinite meaning, but I would say that the reasoning
on physical law is mystic, when there is no distinction made
between the laws of material nature and those of the mind of
man, when there is a confusion between that which is done by
natural law and that which is caused by the spirit of man,
during his observation of the phenomena ; when, for example,
an experimenter must suit his frame of mind to the experi-
ment, or find that nature will refuse to act. It may be said
that such a theory involves the continual presence of God,
supporting constantly his own laws, as in a Hindoo system, f
or it is a theism which makes God everywhere acting, not

* Hoefer. Historie de la Chimie, Vol. i., p. 259.
f Blakey's History of Moral Science.

102 MEMOIR OF DR. DALTON, AND

according to fixed laws, but according to man's deservings.
The latter was not much carried out, and the first corresponds
more closely to the general opinions of these writers. It is a
kind of physical mysticism also to confuse elements with each
other, and powers with substances, a state corresponding
exactly with the mysticism of a more mental character, which
confounds the Deity with his creatures, and desires to absorb
embodied man in his unembodied creator.*

The four elements were preserved amongst the Arabians,
and their corresponding qualities, hot, cSld, dry, aud moist,
and the most wonderful power was given to a mixture of
them all ; it was in this way that " Hai Ebn Yokdan was
produced without father and mother ; it chanced that a certain
mass of earth was so fermented in some period of years, that
the four qualities, viz., hot, cold, dry, moist, were so equally
mixed, that none of them prevailed over the other."! This
was Avicenna's opinion of what was possible.

Fermentation was a favourite method of explaining difficult
phenomena, and is now. As it has now been to a great extent
explained, the lovers of the occult will be obliged to seek
deeper for their theories.

We may find then another origin for the mystic mode of
viewing matter, as well as for the four elements, as far east
as Hindostan, from which the Arabians may have brought it ;
but we cannot, with historical certainty, trace it to its home ;
and it is possible that these two origins, Asiatic and Egyptian,
may have been originally the same. But what is clear to me
is, that the style of the alchemist had the same origin as the

• Whilst this Memoir was being printed, I obtained the " Hours with
the Mystics," by Robert Alfred Vaughan, B.A., who says, vol, 1, p. 26;
••mysticism, whether in religion or philosophy, is that form of error which
mistakes for a divine manifestation the operations of a merely human faculty."
This has no doubt influenced the expressions used above. Hoefer has observed
the connection between the religious writers of early centuries, but has not
traced it up.

f The Improvement of Eluman Reason, exhibited in the Life of Hai Ebn
Yokdan, by Abu Jaafar Ebn Tophail. Translated by Simon Ockley, A.M.

HI8T0BT OF THE ATOMIC THEORY. 103

mystic style introduced into religion and philosophy. The
same condition of mind would produce both, according to the
subject to which it was applied, and that condition seems to
have a historical as well as natural connection.

Albertus Magnus followed closely the reasoning of Avi-
cenna. He was born in 1 193, a few years earlier than Roger
Bacon. Some of his opinions on matter shew distinctly their
origin. He says,* "That matter and power are the prin-
ciples of each body is clear from the reasoning ; for having
taken away all the accidental forms, we arrive at length at a
substantial form, which being removed by the intellect, there
remains a something very occult, which is the first matter."
(Tandem venitur ad formam substantialem qua adhuc abstracta
per intellectum ; remanet quoddam valde occultum quod est
prima materia.) He says also, cap. iii., " Matter has a natural
appetite for form." He discusses whether the metals are gene-
rated, and decides by a peculiar reasoning that the materia
prima is not generated, but created, " because if it were
generated it would be from some other matter, therefore
matter would contain other matter, and so on without end ;
therefore the first matter is not generated, but created.
Creation means to make out of nothing." But the elements
may be generated, and Albertus Magnus easily changes one
into the other. " The generation of one is the corruption of
the other, and e converso* From the generation of one then
follows the corruption of the other." f

That the four elements held their ground we see from no
one more clearly than Roger Bacon, born 1214. We see
there, too, the opinion that the original matter, yle, has none
of the qualities of a body, but is matter in the abstract. His
words are : —

" Elementa sunt quatuor, ignis, aqua, aer, terra, modi id est

• In the portion of his work on natural philosophy, entitled " Physicorum,"
cap. 2. ^

t His chapter, De Oeneratione Elementorum-

104 MEMOIR OF DR. DALTON, AND

proprietates, sunt quatuor, calor, frigiditas, siccitas et humi-
ditas ; et yle est res in qua non est calor, nee frigiditas, nee
siccitas, nee humiditas et non est corpus. Et Elementa sunt
facta de yle ; et unumquodque elementorum convertitur in
naturam alterius elementi et omnis res in quamlibet. Nam
hordeum est equus per vim, id est, naturam occultam; et
triticum est homo per vim, et homo est triticum per vim/'*

" There are four elements, fire, water, air, and earth, that
is the properties of their condition are four, heat, cold, dryness,
and wetness, and yle (the true matter) contains no heat, nor
cold, nor dryness, nor wetness. The elements are made of
yle, and each of the elements is converted into the nature of
the other element, and everything into anything else. For
barley is a horse by possibility, that is, occult nature, and
wheat is a possible man, and man is possible wheat." f

This explanation is exceedingly clear and rational, and
founded on a good deal of observation. We see here in
Roger Bacon's ideas, which are truly in the spirit of the
ancient philosophers, the atomic being excepted, that all
being might arise from this source, called yle. There is,
however, an improvement in the mode of expression; we
understand perfectly what he means, and there is a terse-
ness seldom, if ever attained, either by those before him, or
after him. It separates him from the mystics, properly so
called, although there is the easy passage of one element into
the other, and the unsubstantial principle from which all are
made.

To this scholastic form the mystic method attached itself,
coming apparently with the Arabian learning into Europe, as
well as by direct transmission through Greece and Rome,
having lived for some centuries with little growth, and destined
to be led with more vigor towards its extremes by the reviving
intellect of the West.

* De Arte Chymiae. f This y]e is the Greek v\?/, matter.

mSTORT OF THE ATOMIC THEORY. 1 06

The method of viewing matter being sufficiently confused
by any one of the systems, was not less so when they were
united, or rather, I may say, carelessly mixed and confounded.
When we add to them an infusion not only of the moral and
religious method, but of morals and religion themselves, as
elements in the production of results, we have a system of
nature which all minds refuse to contemplate with patience,
and on which our imagination refuses long to rest, so be-
wildering is it to the one, and so wanting in beauty to the
other. But in a history of man it will always form an im-
portant chapter; as a dissection of the njind it will always
have a psychological value, and as a portion of the progress
of physics it will never cease to be worth preserving for at
least one lesson to the student.

The Arabian chemists who took the lead in introducing it,
acknowledge Geber to be their master, and he composes metals
of sulphur and mercury. At the same time he says, " We see
no ox transformed into a goat, nor any one species transmuted
into another, or by any other artifice so reduced. Therefore,
seeing metals differ in themselves, can you transform one into
another, according to its species, or of such a species make
such a species? This seems to us sufficiently absurd, and
remote from the verity of natural principles. For nature
perfects metals in a thousand years ; but how can you, in your
artifice of transmutation, live a thousand years, seeing you are
scarcely able to extend your life to a hundred ?" He considers
the work as done by the stars, which cause the generation
and corruption, but being ignorant of their power, we cannot
use it. " Likewise, also in things natural, this is the order ;
it is easier to destroy them than to make them. But we can
scarcely destroy gold, how then can we presume to fabricate
the same?"

He was, therefore, not a gold maker, although holding the
abstract theory of the possibility of transmuting. His fol-
lowers did not follow him in this, and whilst quoting his
p

lOG MEMOIR OF DR. DALTON, AND

authority, probably knew nothing of his more rational practice;
they evidently retrograded, but it was probably needful, in
order to satisfy themselves.

A few specimens of the Stoechiometry of the period onward
to Boyle will be needful to explain to what a woeful state the
science fell ; or shall we say rather what a dreadful struggle
it had to come to the light ; or shall we say that it was only
in analogy with the general opinions of the times, and a
picture of the general state of mind? For the honor of
human nature I would prefer to say that the highest minds
being engaged in the cultivation of the more spiritual facul-
ties, in the development of the moral nature of man, in
struggling for freedom of body and of mind ; the lower ones
were engaged with science, and lived a miserable existence,
fed by the crusts from the table of the brighter intellects. We
may add also that science w^as, with many persons, as now,
a mode of making money only ; and many who had no love
for it, joined in the pursuit, and are now by us apt to be
confounded with true men. This explains many, but not all
the cases.

Science and religion have always influenced each other,
and it is interesting to trace them. In the Tractatus
aureus, by a German philosopher, the piety is seen. In
making experiments, he says to every pious God-fearing
chemist: "Above all it is needful to be pious, to lift the
heart to Him, with true, ardent, and not doubtful prayer,
and to ask the gift from Him only."* Again, of the Quinta
essentia, "It is the universal and scintillating fire of the
light of nature, which has the celestial spirit within it animated
in the beginning by God, and penetrating all things, called
therefore, by Avicenna, the spirit of the world. For as the
soul is found in all the members of the human body, and
moves itself, so this spirit is found in all the elementary

■ Museum Hermeticum, page 80.

HISTORY OF THE ATOMIC THEORT. 107

creations, which is also the indissoluble connection of body
and soul, and so is a most pure and noble essence, full of
wonderful efficacy and virtue, in which all mysteries lie hid." *

What this was we see better in the next quotation from
Mehung". " Now I consider you informed of this valuable
truth, that there is no element which is not worked into
another, so that operating on one, the other is operated on.
For example, fire is worked into air and earth, if fire excites
the operation. The earth is the mother and sustainer of all
things ; as all things under heaven which are subject to putre-
faction, are produced by birth in the warmth of its womb.
Only the power of God allows me to return the four elements
again into the fifth essence, and that is called the prima
materia, which is mixed generically in every element." f
(Quae in uno quolibet elemento generice mixta est.)

The idea that all things grew was a common one to them,
as well as to Dr. Johnson, of modern times, and of great
learning. That every thing grew from seeds, is said to be
the most ancient of doctrines. | There is no detail as to
whence the increase of volume came ; growing was the cause
and the explanation. As it is said in " The way of Truth,'*
** so long as you boil, so long you putrefy it, and the
substance is exposed to putrefaction, like corn which is thrown
into the earth, and which is preserved in the earth itself by
the heat of the sun, but must putrefy by natural rain before
anything new will grow from it." ||

And Basil Valentine, " on the philosopher's stone," says,
" the vivifying power of the earth produces all things which
spring from it, and he who says that the earth is without life,
speaks contrary to truth. For the dead can supply nothing
to the living, and neither can the dead grow, because the

* Museum Hermeticum, p. 84.

t Id., p. 151. DemoDstratio Naturae. By Mehung.

X Amtotle, quoted by Hitter, Vol. i., p. I80.

n Idem p. 186.

108 MEMOIR OF DR. DALTON, AND

spirit of life has fled ; therefore the spirit is the life and soul
of the earth, it dwells in it, and is operated on from
celestial and sidereal, into terrestrial ; for all herbs, trees, and
roots, as well as metals and minerals, receive their strength,
increase, and nourishment from the spirit of the earth." *
Although this leads to conclusions beyond the known facts,
it is a style of reasoning not to be entirely found fault with,
and much less can it be called irrational. It is a kind of
middle path between calling earth an animal and our present
opinions ; but Basil Valentine showed intellectual vigor, and
formed an epoch in his science. He was born about 1413.

Raymund Lully, who takes us back again to the age of
Albertus Magnus and Roger Bacon, was universally quoted
by alchemists as a great master, he was born about 1235.
He writes ;

" Matter says I am a being from which something is made
by passionhood,'\ and that substantially and accidentally,
because I am the leader, since from me who am the primi-
tive is made that particular matter which is the substantial
part of substance, as the matter of a rose, of a horse, and so
on. — God is my end and cause, and I am simply his effect. —

" Matter says, I am absolute passionhood under absolute
form to which I am conjoined, and as all the river waters are
derived from the sea and return to it, so from me are derived
all matters in particular because I am absolute."

" Again matter says, I am not a being absolutely existing,
potentially so ; because, if so, the subject in which I am
would be sustained potentially, and so successively ad in-
Jinitum, which is impossible. I am, therefore, a being
existing potentially to all particular substances existing under
particular forms."

" In my nature there is not found form, which is from me

* Museum Hermeticum, p. 403.
t I imagine this word to imply better than any I know the state of ready
excitability to impressions.

HISTORY OF THE ATOMIC THEOKY. lOQ

and on account of me, because if so I should not be absolute
passionhood and my parts would be deprived by me of essence
and nature, which is impossible since I am simply absolute."

" Matter says, I am individualised by quantity, as when I
am so much ; either long, broad, or deep ; either round, in a
circle, or spherical body ; or qualified, for example, when
shining or warmed in flame and reddened in red wine, sweet-
ened in honey, heavy in earth, or become light in the fire."

Some may prefer the original of this ; —

Ait materia : ego sum ens ex quo fit aliquid passionando et hoc
substantialiter et accidentaliter, qui^ dux sum, quoniam ex me quae
sum primitiva fit materia particularis quae est substantialis pars sub-
Ptantiae. *****

Ipse (Deus) est meus finis, mea causa prima, et ego sum eflfectus
simpliciter ejus.

Ait materia^ sum absoluta passio sub absoluta forma sub qua sum
conjuncta et sicut ex mari derivantur omnes aquae fluviales et ad
istud revertuntur, sic a me derivantur omnes materiae particulares
et ad me revertuntur, qui^ absoluta sum. Rursus ait materia. Non
sum ens existens in potenlia absolute, qui^ si sic subjectum in quo
essem, sustentata esset in potentia et sic successive in infinitum quod
est impossibile. Sum ergo ens existens in potentia ad omnes sub-
stantias particulares sub formis particularibus existentes.

In mea matura non invenitur forma quae sit ex me atque propter
me, quik si sic, non essem passio absoluta et secundum quid meae
partes essent ^ me ab essentia et natura privatae, quod est impos-
sibile, cum sim simpliciter absoluta.

Ait materia. Individuata sum per quantitatom cum quae sum
quanta, ut puta longa, lata, et profunda, aut in circulo vel in corpore
sphaerico rotunda: sum qualificata, ut puta in fiamma lucefacta, cale-
facta ; et in vino rubro rubefacta, in melle dulcificata, et in terra
ponderosa ; et in igne levificata.^

He recognises the four elements, and believes them to exist

• Raymandi Lullii Opera— Philosophiae Principiu — De Materia. Strasburg,
1600. I suppote more than one mistake to occur in the Latin. I may be
wrong, but it is quoted correctly.

1 10 MEMOIK OF DR. DALTON, AND

in all things elemented. We see in him great acuteness of
thought and much valuable observation, and need not wonder
that he was a great master among succeeding alchemists.
We see in him the Greek mode of reasoning on the abstract
principle of matter, but the word which was intended only for
a general name, comprehending all substances, is taken for
an existence by itself. I know that there are other means of
getting into the same difficulty, but we find the alchemists
haunted by the ghost of the fine abstractions of Plato's divine
ideas of things existing on earth, and the belief in abstract
matter, and not seeing the intellectual origin they seek to
find them out in substance, and so we have a search for
the prima materia^ which orginally had no power of being
handled, and scarcely of being conceived.

They tried in vain to hunt the ghost down, and to handle
it in their fingers. Whilst the intellect was unable to grasp
the idea, they actually sought to catch it in a bottle. This
misconception, so singularly ludicrous, makes me suppose
that the class of minds generally engaged in chemistry were
inferior, but it may be enough to suppose that the mistake
once made was not easily rectified. It seems to me to be
without doubt that this is the origin of the singular alchemistic
chase. If " immaterial substance " was a " philosophical im-
posture in philosophy," as Coward called it last century, how
much more has it been to alchemy. Yet, I know a living
and intelligent man who searches for the prima materia. It
may truly be said that the world is governed by ideas.

This matter having become on one side a mere substance,
it is not to be wondered at that on the other side it became
entirely the opposite, and was a representative of abstract
force, as we may see in expressions of Plotinus, and others of
the time, which it would take too much time to quote.

Again, we have a search for the fifth essence, which con-
tained all things and was made up of all things. Here is
an evident proof of a decrease both of intellectual power and

HISTORY OF THE ATOMIC THEORY. Ill

of knowledge, and an illustration of the danger of a little
learning.

This prima materia was even supposed by some to be the
substance on which it was needful to begin to operate,
so far had it descended. Flamel says, " Having thus obtained
this delicate and precious book, I did nothing else day and
night but study upon it, conceiving very well all the opera-
tions it pointed forth, but wholly ignorant of the prima
materia with which I should begin, which made me sad and
discontented." * Although this, as is afterwards shewn, was
a matter of preparation also, the point of departure of the
second process.

Artephius, who lived in the twelfth century, and was bom,
according to his own account, in the second, and wrote a
book on prolonging life at the age of 1052! may be quoted
as a true mystic chemist, shewing us, too, by the numerous
names that he gives to this liquid, that he even at that time
inherited it from a long ancestry. " Our dissolving matter,
therefore, carries with it a great tincture, and a great melting
or dissolving ; because that when it feels the vulgar fire, if
there be in it the pure or fine bodies of sol or luna, it imme-
diately melts them, and converts them into its white substance,
such as itself is, and gives to the body colour, weight, and
tincture. In it also is a power of liquefying or melting all
things that can be melted or dissolved ; it is a water ponder-
ous, viscous, precious, and worthy to be esteemed, resolving
all crude bodies, into their prima materia^ or first matter,
viz., into earth and a viscous powder, that is into sulphur and
mercury." The indefinite notion of the origin of properties
we see, when he says, " the property, therefore, of our water
is, that it melts or dissolves gold and silver, and increases
their native tincture or colour; for it changes their bodies

• The Lives of the adepts in Alchemystical Philosophy, with a Critical
Catalogue of the Books in this Science, and a Selection of the most celebrated
Treatises on the Theory and Practice of the Hermetic Art. Page 34.

1 12 MEMOIR OF DR. DALTOX, AND

from being corporeal, into a spirituality, and it is this water
which turns the bodies or corporeal substance into a white
vapour, which is a soul that is whiteness itself, subtle, hot,
and full of fire."

Here is an attempt to separate chemical action from
mechanical. " It appears then that this composition is not a
work of the hands, but a change of the natures; because
nature dissolves and joins itself, sublimes and lifts itself up."
The nature of the treatises which he studied is seen in a
quotation of his own, "It is also the most acrid vinegar,
concerning which an ancient philosopher has said, I besought
the Lord and he shewed me a pure clear water, which I knew
to be the pure vinegar, altering, penetrating, and digesting.
I say a penetrating vinegar, and the moving instrument for
putrefying, resolving and reducing gold or silver into their
prima materia or first matter." *

That the chief aim was this originally metaphysical idea of
matter, we see also as late as 1691, in the Second Aphorism
of " Baron Urbiger," whose more modern style has helped him
to a more condensed expression. " An indeterminate matter
being the beginning of all metals and minerals, it follows, that
as soon as any one shall be so happy as to know and conceive
it, he shall easily comprehend also their natures, qualities, and
properties." " It is found every where, at all times, and only
by our science."

A favourite mode of representing chemical action, was by
the analogies in the growing of plants and animals. Zosimus
says it is the (Hydrargyrum) water-silver, the male-female
principle, the principle always escaping constant in its pro-
perties. The same idea proceeded forward, and in 1409,
Nicholas Flamel says, " minerals taken out of the earth may
be changed if beforehand they be spiritualized, and reduced
into their sulphureous and argent-vive nature, which are the

* Idem. The Secret Book of Artephius.

HISTORY OF THE ATOMIC THEOKY. 113

two sperms, composed of the elements, the one masculine, the
other feminine. The male sulphur is nothing but fire and
air; and the true sulphur is as a fire, but not the vulgar,
which contains no metallic substance. The feminine sperm
is argent- vive, which is nothing but earth and water," &c.
And Norton, about the same time, reasons thus ;

" Metalls of kinde grow lowe under grounde,

For above erth rust in them is found ;

Soe above erth appeareth corruption

Of metalls, and in long tyme destruction.

Whereof noe cause is found in this case.

But that above erth thei be not in their place.** *

But he denies, like Geber, any growing in glass vessels ;

" For cause efficient of mettalls find ye shall.

Only to be the vertue minerall,

Which in everie erth is not found,

But in certain places of eligible ground."

When once grown, however, they could not multiply
according to him ;

" Trewly ye maie trust as I said before,

How of one ounce of silver, maie silver be no more."

But this was not the general opinion, as they were supposed
to grow in the preparation, as Ripley says; On calcina-
tion, v. 15 ;t

** If thou intend therefore to make
Gold and sylver by craft of our philosophy ;
Thereto nother eggs nor blood thou take,
But gold and sylver which naturally,
Calcyned wysely, and not manually.
And new generation wyll forth bryng,
Incresying theyr kynde aa doth each thyng."

As metals grew by their life, and life is the blood, so it was a
desirable thing to find out the blood of metals ;

" The true blood of mettalls is hard to have.''^

As the prima materia was of indeterminate properties, was

• Ashmole's " Theatrum Chemicum," 1652, pp. 18, 19, and 20.
t Same, p. 132.
X ** Anon." Same, p. 406.
Q

1 14 MEMOIR OF DR. DALTON, AND

in fact originally only an intellectual conception, come to in
the consideration of matter, abstracted from its apparently
unnecessary properties, and converted into a reality by the
alchemists, so they, in their turn, converted their elements,
which are partly the usual four, partly sulphur and mercury,
or with salt added, into mere abstract ideas. Their sulphur
was an ideal sulphur, and Paracelsus gave every body its own
peculiar sulphur and other elements. This was a step to-
wards a recognition of many distinct indestructible bodies,
and a progress out of the purely mystical consideration of the
subject.

The opinions held generally by alchemists, having arisen,
as I think, from the spiritual and religious state of man, more
than his directly intellectual, it would require more space than
can be given here for a history such as would suit this view of
the case. The early Greek manuscripts, mentioned by Olaus
Borrichius, and partly given by Hoefer, show the inclination
there was to write with, or to proceed from, the current
religious opinions. Isis and Osiris were important alchemistic
names from the Alexandrian school, and salt, sulphur, and
mercury, have been connected with the trinity of Christians.

It is not the place here to follow the detailed opinions of
the alchemists, they are taken rather in the mass, and twelve
or fourteen hundred years of their opinions thrown with little
order together. This I see no great reason to alter, the men
differed so little in their radical opinions. Salt, sulphur, and
mercury, were sometimes the origin of the metals, sometimes
of all things, each had its own spiritualization, each was the
greatest or the least in its turn ; and as a curious instance of
recurrence of opinion, we find Palissy, in the 16 th century,
a man full of shrewdness of observation, saying, as Thales
did so long before, " that the commencement and origin of
all natural things is water." * But then he believes in more

* p. 217. Oeuvres Completes de Bernard Palissy. Edition par Paul
Antoine Cap, J 844.

HISTORY OF THE ATOMIC THEORY. 1 1 5

than one kind of water, one of which he considers a fifth
element. This, however, has to do with the history of the
idea of liquid and fluid, which must not be entered on here.
In saying this, Palissy was reasoning from the state of metals
in solution, for he believes they grew, and were found in
common water. As he says ;

" 11 (le createur) a commande ^ nature de trauailler, produire
et engcndrer, consommer et diasiper ; comme tu vols que le feu
consomme plusieurs choses, aussi il nuurrit et soustient plusieurs
chosesi les eaux debordees dissipent et gastent plusieurs choses,
et toutefois sans elles nulle chose ne pourroit dire ie suis. £t
tout ainsi que I'eau et le feu dissipent d'vne part, Us engendrent et
pro(^ulsent d' autre. Suyuant quoy ie ne puis dire autre chose des
metaux, sinon que la matiere d' iceux est vn sel dissoult et liquifie
parmy les eaux communes, lequel sel est inconneu aux hommes;
d'autant qu' iceluy estant entremesle parmi les eaux, estant de la
mesme couleur que les eaux liquides et diafanes on transparentes, U
est indistinguible et inconnu a tous ; n' ayant aucun signe apparent,
par lequel les hommes le puissent dislinguer d' auec les eaux
communes.***

Matter then appeared to the alchemists as it has done to
the greater part of early thinkers, and to most of those who
do not think, as a power subtle and changeable, capable of
every transformation, and dependent on laws by some held
eternal and immutable, by others dependent on the spiritual
condition of man. We have no distinct clue in such opinions
to any definite ideas about composition.

* Same, p. 104. Id his objection to alchemy, Palissy has not shone so much
at in his pottery, and even in his other scientific inquiries. Botticher, also a
potter, a less honourable and less able man, has beun, by his discoveries in
Dresden porcelain, the occasion of a saying suitable to the times, and shewing
the true value of the alchemists, viz ; their accidental discoveries iu the arts.
When his gold making failed, and he made porcelain, it was said —

O Gott Du ftroaser Fchoepfer,

Ana einem goldmaober wird ein Toepfer.

Ye heavens, alchemy has win my votes,
A goldmaker's changed to a maker of pots.

p. 303. Hist. Crit. Untersuchung der Alchemie. By Wiegleb, 1701.

116 MEMOIR OF DR. DALTON, AND

On the four elements we have occasionally opinions which
may be called definite, as when they are said to form various
combinations with various properties, but these are held with
no tenacity. In the salt, sulphur, and mercury, we have a
clue to definite composition, but we have seen them spiritua-
lized and held with still less tenacity. In the elements of
Leucippus, Democritus, and Lucretius, we have a definite
view taken of the subject, but that was soon neglected, to
be revived in part when alchemy was falling. We have had
an approach to a distinct view before us in that of forces, or
unextended points, forming the origin of matter, brought for-
ward later, and, perhaps, in an entirely original form, but at
least more detailed, by Boscovich.

HISTORY OF THE ATOMIC THEORY. 1 17

CHAPTER VI.

OPINIONS DURING THB TRANSITION FROM ALCHEMY
TO CHEMISTRY.

The ages so rapidly passed over comprehend two thousand
years. The attainment in chemical science has been as yet
small. All the theories have been abstract ; they have been
efforts of the mind to comprehend matter, with a very
meagre, if any, classification of phenomena. We might ask
ourselves if this was caused by the scarceness of facts, or by
the want of a mind to perceive them. As to scarceness of
information this may be doubted, numerous truly chemical
arts had been from early ages in use ; many had fallen into
disuse. The observers that now come to the science are not
so much characterized by the multitude of their discoveries, as
by the minuteness of their observations, and the penetrating
nature of their reasonings. The progress of mankind has often
been compared with the progress of individuals, and the
analogy serves here to point out a cause. In the history of
every mind, especially of the mind of the student, there are
seasons where facts are collected and books read with diligence,
theories formed in great numbers, reasonings adopted and
thrown aside ; opinions are heaped up, but no distinct opinion
is formed, and a vague stare into the difficulties before it is
the only result of the labour, for knowledge it can scarcely be
called, where nothing is well arranged, and nothing is actually
known. The imagination then takes the place of the helpless
reason. A poetical mind may find in this state a field for its
highest powers, a weaker mind will seek explanations more
or less mystical, and a still weaker mind will be contented
with the merely mysterious. But a vigorous mind, in which
reasoning and observation predominate, is found gradually to

118 MEMOIR OF DR. DALTON, AND

collect from the disorderly information, certain impressions,
which, in time, become more distinct, until at last an idea is
obtained which can be laid hold of. Whether this idea be false
or true, is of little consequence ; it is in any case enough to
give order to the museum of his mind, and for the first time
that mind may be said to be informed. Every thing is
examined under the influence of this idea, which may change
constantly, as it is constantly seen to be unsuited to the facts,
but every change may be a progress ; and even if from false
to false, is nevertheless a constant gain, so much false being
left behind. The dreaming age of chemistry had lasted long;
the minds occupied had been satisfied either with the more
poetical observation of nature, or with the mystic and
mysterious; an idea had entered into the mind of the chemists
of the age, that some exact explanation could be obtained,
and so we find them hunting it down from point to point with
acuteness, energy, and hope, ever increasing as the object
seemed rapidly to be approached. But how was this idea
first attained? How does the first idea rise in the mind of
the individual enabling him to see order and beauty in all the
shapeless learning that he had been amassing ? It is a progress
of mind which is not for us to discuss here. The requisite for
it is intellectual energy, and how that has been aroused in
modern Europe, many great writers have done their best to
show. It was by a combination of many great causes,
natural stages in the education of the species. We are sur-
prised to find that the finest writers of the world should have
existed when thinkers in science were scarcely at the rudi-
ments ; but we see constantly that the highest literary powers
may be unfit to comprehend any scientific truth firmly, and we
see, even among the scientific world, that some branches have
still scarcely begun their independent life. The world culti-
vated poetry and eloquence, and attained the highest stage that
we know, when no law in the mixed sciences could be rigidly
and certainly stated. The writers, quoted in this chapter,

HISTORY OF THE ATOMIC THEORY. 1 19

go over again much of the same theoretical ground traversed
before, but frequently with much less philosophical grasp than
the ancients, and much less largeness of conception, although
they frequently gain by what seems the littleness of their
ideas, and the smallness of their aims. They are contented to
speculate on an acid, instead of the formation of a world,
whilst those who take a wider ground, such as Newton and
Boscovich, can only be sSid, as far as our subject is concerned,
to reproduce and improve earlier philosophies.

The tendency from this time is to increase the number of
bodies, which, if not at first called elements, are at least
treated as such. This is a needful step towards the chemical
theory of matter in its present stage.

Glauber, although a believer in the general transmutability
of substances, did much to help forward the notion of distinct
elements in his observations on the aflfinity of bodies. He
explains the evolution of ammoniacal gas from sal ammoniac
by a fixed alkali, showing that he understood well combi-
nation and decomposition, the stumbling-block of so many,
and the introduction to <lefinite compounds. " But that a
spirit is distilled off by the addition of fixed salts ; the reason
is that fixed salts are contrary to acid salts, and if they
get the upper hand do kill the same, and rob them of their
strength, whereby those things which are mixed with them
are freed from their bond, and so it falls out here with salt
armoniack, that when by addition of a vegetable fixed salt, tho
acidity of the salt armoniack is killed ; the salt of urine, which
formerly was bound therewith, gets its former freedom and
strength, and being sublimed turns into a spirit." *

Boyle, who attacked alchemy, and may almost be said to
have begun modern chemistry, or rather let us say the transi-
tion period, seems to have had one of the clearest, most
straightforward, and most common-sense methods of viewing

* Page 40. The Works of the Highly Experienced and Famous Chyroist,
John Rudolph Glauber. London, IC39.

120 MEMOIR OF DR. DALTON, AND

phenomena, of any of his period. One feels, on reading his
works, that on another subject he might have written so as to
be even now and at all times read with delight, whereas, in the
dangerous and difficult fields of chemistry, he has only left
matter serving as landmarks, to shew us the way in which
the mind has been obliged to wander in search of truth.

Boyle says, when treating of the " origin of form and quali-
ties," * " There is one universal matter common to all bodies,
an extended, divisible, and impenetrable substance."

And in the " Sceptical Chemist." f " But the Aristotelian
hypothesis (i.e., of tlie four elements) is not comparable to the
mechanic doctrine of the bulk and figure of the smallest parts
of matter, for from these more universal and fruitful principles
of the elementary matter, may spring a great variety of
textures, upon whose account a multitude of compound bodies
might greatly differ from one another." In p. 282 : — " Now
if it be true, as 'tis probable, that compound bodies differ from
one another, in nothing but the various textures, resulting
from the magnitude, shape, motion, and arrangement of their
small parts, it will not be irrational to conceive that one and
the same particle of universal matter, may by various altera-
tions and contextures be brought to deserve the name some-
times of a sulphureous, and sometimes of a terrestrial or
aqueous body."

He attacks severely the four elements, the three elements,
and the five elements, and justly complains of the " intolerable
ambiguity " of the writers on chemistry, and " their playing
upon words," as their mode of using salt, sulphur, and mercury
decidedly is.

To continue from Boyle. " It seems probable that at the
first production of mixt bodies, the universal matter whereof
they consist was actually divided into little particles of several

* Vol. I., p. 197. The philosophical works of the Hon. Robert Boyle, Esq.
Abridged, methodized, &c., by Peter Shaw, M.D. 2nd edition, 1738.
t Vol. III., p. 200.

HISTOKT OF THE ATOMIC THEOBY. 121

sizes and shapes variously moved. • ♦ • • »'pjg ^jg^
possible, that of these minute particles many of the smallest
and contiguous ones were associated into minute masses, and
by their coalitions constituted such numerous little primary
concretions, as were not easily separable into the particles
that compose them." *

t "And indeed if we consider how far the bare change
of texture, whether maffe by art or nature, can go, in pro-
ducing such new qualities, in the same parcel of matter ; and
how many inanimate bodies we know to be denominated
and distinguished, not so much by any imaginary substantial
form, as by the aggregate of these qualities ; and that the
variation of figure, size, motion, situation, or connection
of the corpuscles, whereof any of these bodies is coiHt
posed may alter the fabric of it; we shall have cause to
suspect, that there is no need that nature should always have
elements provided, whereof to compose mixed bodies; and
that it is not so easy as chymists and others have hitherto
imagined, to discern which among the many different sub-
stances, without any extraordinary skill, to be obtained from
the same portion of matter, ought, exclusive of the rest, to be
esteemed its elementary ingredients ; much less to determine
what primogeneal and simple bodies conspired together to
compose it." ♦ ♦ * •

" Our experiment affords us a considerable argument in
favour of that part of the mechanical hypothesis which teaches
inanimate bodies to diflfer from one another, but in the magni-
tude, shape, motion, texture, and, in a word, the mechanical
properties of the minute parts they consist of." Page 360.
At the end of the chemical doctrine of qualities, p. 441, — " In
short, these hypotheses greatly hinder the progress of human
knowledge, that introduce morals and politics into philosophy,
where all things are transacted according to mechanical
laws."

• Vol. III., p. 263. t Pag« 850.

122 MEMOIR OF DR. DALTON, AND

The doctrine of elementary atoms, either in the sense of
indivisible or merely undivided, leads us to suppose all things
formed of one substance only ; and this seems to have been
the notion of those who have held it up as a solution of the
question, although generally it has not been carried out far
enough to arrive at the difficulties. If all the elementary
bodies are the same as this notion supposes, every change is
made by change of position of the particles. This is the
early doctrine again.

In speaking of the atoms, Boyle says, " little particles of
various sizes and shapes variously moved." This "variously
moved" introduces a force; it is the introduction of various
powers and qualities, and, consequently, of what we term
elements. This shews the difficulty of obtaining correct
language, when Boyle, whose object was to be accurate,
seemed to have overlooked this in those few but important
words.

I may quote the graphic words of Boyle, shewing what
confused ideas reigned on the nature of combination. " Hel-
mont we know, too, asserts that all mixed bodies spring from
one element; and that vegetables, animals, marcasites, stones,
metals, &c., are materially but simple water, disguized into
these various forms by the plastic virtue of their seeds."*
** Aristotle tells us, that if a drop of wine be put into ten
thousand measures of water, the wine being overpowered by
so vast a quantity of water, will be turned into it. But if
this doctrine were true, one might hope, by melting a mass
of gold and silver, and by but casting into it lead and anti-
mony, grain after grain, we might, at pleasure, within a
reasonable compass of time, turn what quantity we desired
of the ignoble into the noble metals." f

Lemery, born about twenty years after Boyle, felt, but
not very clearly I imagine, some of these difficulties, as he

♦ Sceptical Chymist. Vol. III., p. 284. f Page 289.

HISTOfiY OF THE ATOMIC THEOBY. 123

says, " the first principle that can be admitted for the com-
position of mixts is an universal spirit, which being diffused
through all the world produces different things according
to the different matrixes or pores of the earth in which it
settles. But, because this principle is a little metaphysical,
and falls not under our senses, it will be fit to establish some
sensible ones." *

Here, again, is a notion that matter is one, but with an
addition that the different properties of its parts are caused by
abstract qualities; here there is nothing said either of particles
or transformations. It would seem as if matter existed in
some condition as one, and received qualities from a spirit
which had the power of giving various qualities. We see
no variety of agents, but one agent; so that a will and design
are constantly required to be present.

This is manifestly a backward step from Boyle, who was
not well followed up in his own direction.

Mayow, of Oxford, wrote in 1673 definite opinions as to
the combination of acid and alkali, shewing that sulphuric
acid separated nitric from saltpetre, and formed vitriolated
tartar, or sulphate of potash, that therefore the nitric acid was
not destroyed when it united with potash, seeing that it could
be separated again by the sulphuric acid. Although we can-
not separate the sulphuric acid from the potash, "it is not
because these salts have mutually destroyed each other, but
because there is nothing in nature which unites with each
more firmly than they do among themselves."! He also
clearly shews that alkalies throw down metals from their
solutions.

" These important observations of Mayow were continued
still further by Geoffroy Senior. He considered the order in

• Page 2. Lemery's Cour»e of Chymistry. Translated by Walter Harris,
M.D. London, 16S6.

t Tractatui quinque Medico Physici, 1674. Chapter, " De salium contra-
riomm congrettu et precipitatione."

124

MEMOIR OF DR. DALTON, AND

which bodies separated each other from a given body as con-
stant. Thus metals are separated from acids by the absorbent
earths; the absorbent earths are separated from acids by
volatile alkalies, while volatile alkalies are separated by the
fixed alkalies. He drew up, in consequence, the following
tables, exhibiting the order in which bodies separate each
other from a given substance. At the head of each column is
written the name of the substance with which the bodies,
enumerated in the column, combine. Below it are arranged
all the bodies capable of uniting with it. That which separates
all others is placed uppermost, and that which is separated by
all the others is placed undermost, and the others in the order
of their separations. Thus, in the first column, the fixed
alkalies separate all the bodies below them from the acids.
The volatile acids separate all except the fixed alkalies. The
absorbent earths separate the metals, and the metals are
separated by all the other bodies in the column."

ACIDS.

MURIATIC
ACID.

NITRIC ACID.

SULPHURIC
ACID.

ABSORBENT
EARTHS.

fixed alkalies

tin

iron

phlogiston *

sulphuric acid

volatile alkalies

antimony

copper

fixed alkalies

nitric acid

absorbent earth

copper

lead

volatile alkalies

muriatic acid

metals

silver

mercury

absorbent earth

mercury

silver

iron

gold

copper
silver

FIXED

VOLATILE

METALS.

SULPHUR.

MERCURY.

ALKALIES.

ALKALIES.

sulphuric acid

sulphuric acid

muriatic acid

fixed alkalies

gold

nitric acid

nitric acid

sulphuric acid

iron

silver

muriatic acid

muriatic acid

nitric acid

copper

lead

acetic acid

acetic acid

lead

copper

•ulphur

silver
antimony
mercury
gold

zinc
antimony

* Geoffrey's expression isprincipe huileux. Kopp's Geschichte der Chemie.

HISTOBY OF THE ATOMIC THB(»IY.

125

LEAD.

COPPEE.

BTLVEB.

IBON.

ANTIMONY.

WATER.

silver
copper

mercury
calamine

lead
copper

antimony
silver, copper,
lead

iron

silver, copper,
lead

alcohol
salt

Thi8, on Geoffrey, is taken from Thomson's Chemistry,
edition of 1817. The tables are in all the older chemical
books. I have not seen the original.

Although these tables were extended and improved by
Gellert and Sage, they were not altered in principle until the
middle of last century. Although every thing is indefinite
here, that is, unfixed by numbers representing either weight or
measure, a certain order is given to the substances known to
chemists, a classification is produced, certain laws are laid
down, and some relation of one body to another is given, at
the same time bodies begin to get a definite character and
position, and are not mixed up in a confused mass together,
capable at any moment of playing the most fantastic tricks
with the operators, and converting the chemist from a natu-
ralist to a magician.

In speaking of atoms we must not confine ourselves to
bodies that cannot be divided ; Newton and others being satis-
fied with such as are not usually divided. Newton's well
known words are these : — " It seems probable to me that
God in the beginning formed matter in solid, massy, hard,
impenetrable, moveable particles, of such sizes and figures,
and with such other properties, and in such proportion to
space, as most conduced to the end for which He formed
them ; and that these primitive particles being solid, are in-
comparably harder than any porous bodies compounded of
them ; even so very hard as never to wear, or break in pieces ;
no ordinary power being able to divide what God himself
made one in the first creation. While these particles con-
tinue entire, they may compose bodies of one and the same
nature and texture in all ages ; but should they wear away,

126 MEMOIR OF DR. DALTON, AND

or break in pieces, the nature of things depending on them
would be changed. Water and earth, composed of old worn
particles and fragments of particles, would not be of the
same nature and texture now with water and earth composed
of entire particles in the beginning. And, therefore, that
nature may be lasting, the changes of corporeal things are to
be placed only in the various separations and new associations
and motions of these permanent particles ; compound bodies
being apt to break, not in the midst of solid particles, but
where those particles are laid together, and only touch in
a few points."^

This is the perfection of the mechanical theory, unaided
by chemistry. It provides for a diversity of particles in
size, shape, and other properties, as well as diversity of
arrangement, and as this explains what may be called the
external phenomena of combination, it is, to a certain stage,
probably the correct one. Our difficulties arise when we
think on the constitution and mode of combination of these
particles. On the first Newton scarcely allows any argument,
on the second he has not said sufficient to satisfy the demands
of chemistry.

Dr. Shaw, although not a great discoverer, was a clear-
headed man, and his chemical lectures, in 1731, 1732, and
1733, are amongst the first in which we see the matter plainly
and practically handled, following up the instructions of
Boyle, which he carefully edited, f

At p. 146, he says : — " We must, therefore, observe that
the more intelligent of the modern chemists do not understand
by principles, those original particles of matter of which all
bodies are, by the mathematical and mechanical philosophers,
supposed to exist. Those particles remain undiscernible to

• Newton's Optics, near the end,
t Chemical Lectures, publickly read at London in the years 1731 and 1732,
and at Scarborough, in 1733, for the Improvement of Arts, Trades, and
Natural Philosophy, by Peter Shaw, M.D., F.R.S. Second edition, 1755.

HISTORY OF THE ATOMIC THEORY. 127

the sense, though assisted with the most finished instruments,
nor have their figures and original differences been determined
by a just induction. Leaving, therefore, to other philosophers
the sublimer disquisition of primary corpuscles or atoms, of
which many bodies or worlds have been formed by the fancy,
genuine chemistry contents itself with grosser principles,
which are evident to the sense, and known to produce effects
in the way of corporeal instruments."

As it is clear that matter has various appearances, so if
there be only one matter, it must be capable of putting on
various forms. This variation of forms has been given as an
innate power of matter, and if we extend this idea, we come
to the conclusion, more or less clearly expressed by many
writers, from the earliest times, that matter itself has no
qualities ; but that we perceive only the qualities it has put
on. Quality means, then, the true matter, or sensible thing
which we see. A great many metaphysical, as well as phy-
sical difficulties have been removed by allowing a greater
number of elements, leaving the difficulties to be solved of a
much more profound character.

The remarkable position given to character, making it play
the part of matter, is seen well in Hooke's works.*

" I conceive the whole of realities that in any way affect our
senses, to be body and motion. By body I conceive nothing
else but a reality that has extension every way, positive and
immutable ; not as to figure, but as to quality ; and that the
body, as body, is the same, whatever figure it be of: as a
quart of water is a quart of water, or a certain quantity of
body, though contained in a globe, cylinder, cone, cube, quart-
pot, or any other figured containing vessel ; and as body, it is
indifferent to receive any figure whatever; nor has it more
extension in the one than in the other vessel, nor can it have

• The Posthumous Works of Robert Hooke, M.D., F.R.S. Folio. 1705.
Pages 17 1 .2. He died in 1 708.

128 MEMOIR OF DR. DALTON, AND

less ; nor is it more essentially a body, when solid, as ice, than
when fluid ; that is, the minims of it are equally disposed to
motion or rest in position to each other ; and therefore body,
as body, may as well be, or be supposed to be, indefinitely
fluid as definitely solid ; and, consequently, there is no
necessity to suppose atoms, or any determinate part of body
perfectly solid, or such whose parts are incapable of changing
position one to another ; since, as I conceive, the essence of
body is only determinate extension, or a power of being un-
alterable of such a quantity, and not a power of being and
continuing of a determinate quantity and a determinate figure,
which the anatomists (or atomists) suppose. These, I con-
ceive, the two powers or principles of the world, to wit,
body and motion^ uniformity of motion making a solid, and
diffbrmity of the motion of the parts making a fluid, as I
shall prove more at large by and by."

* * * * " As for matter^ that I conceive in its essence
to be immutable, and its essence being expatiation deter-
minate, it cannot be altered in its quantity, either by con-
densation or rarefaction ; that is, there cannot be more or less
of that power or reality, whatever it be, within the same
expatiation or content ; but every equal expatiation contains,
is filled, or is an equal quantity of materia ; and the densest
or heaviest, or most powerful body in the world contains no
more materia than that which we conceive to be the rarest,
thinnest, lightest, or least powerful body of all ; as gold for
instance, and cether, or the substance that fills the cavity of
an exhausted vessel, or cavity of the glass of a barometer
above the quicksilver. Nay, as I shall afterwards prove, this
cavity is more full, or a more dense body of aether, in the com-
mon sense or acceptation of the word, than the gold is of gold,
bulk for bulk ; and that because the one, viz., the mass of
sether, is all aether ; but the mass of gold, which we conceive,
is not all gold, but there is an intermixture, and that vastly
more than is commonly supposed, of sether with it ; so that

HISTORY OP THE ATOMIC THEORY. 129

vacuity, as it is commonly thought, or erroneously supposed,
is a more dense body than the gold as gold. But if we con-
sider the whole content of the one with that of the other,
within the same or equal quantity of expatiation, then are
they both equally containing the materia or body."

This argument will not appear so conclusive to his readers,
but it serves well to shew how unsettled were the opinions on
matter, when a man of Hooke's high standing spoke in this
manner. He could not believe in epicureaa atoms as he
called them, and he had as little faith in " the four elements,
the three chemical principles, magnetism, sympathy, fermen-
tation, alkaly, and acid, and divers other chimeras." The
quotation is by no means intended as a specimen of Hooke as
a philosopher. Aristotle's aether and the abstract ideas of
Plato are still perceptible here in confusing the reason and
obliterating the observation.

When a definite form is given to the minutest particles of
bodies, it leads to their indivisibility by a very easy reasoning,
but the moment these ideas become vague, or if a prime matter
is allowed, taking various forms, or a few elements changing
into each other, essentially the same things, then infinite
divisibility is more likely to lay hold of the imagination.

Des Cartes, speaking of the theory of Democritus, says, "it
is rejected because he supposed the existence of indivisible
corpuscles, because there was a vacuum around each, which
could be demonstrated impossible, and because there was
weight given to each, whereas no body has it when taken
alone, its existence depends on the situation and motion of
other bodies."* But he thinks also that natural things might
have been made in various ways. We must explain the
phenomena as we best can. *' Ita non dubium est, quin sum-
mus rerum opifex, omnia ilia quae videmus, pluribus diversis
modis potuerit efficere." t He also retained the four elements.

* Renati Det Cartes, Principia Philosopbiae. Page 219. Amsterdam, 1(377.

•j- Prop. ccii.
8

130 MEMOIR OF DR. DALTON, AND

We find Sennertus, about the same time, expounding
Aristotle's opinions on the elements, and looking to the
authority of character more than experiment, but he does not
give a fifth element such as Aristotle's ether. The argument
he gives that there are only four is curious, and another of the
interminable varieties of method in which vagueness thinks.
" There are two right motions, one from the mean, the other
to the mean, there will, therefore, be an equal quantity of
simple bodies, subject to these two simple motions, one which
absolutely is heavy, called earth ; another absolutely is light,
called fire. But because nature wishes the world to be one,
but contrary extremes cannot constitute one, she always
couples the extremes by means (per media), and connects the
last of the superior kind with the first of an inferior. This
mean is therefore required. But this cannot be one. Because,
if so, it would occupy the mean place between the extremes,
or between the centre and circumference, and so no right
motion (rectus motus) could be given to it. For it could
neither be moved to the middle, nor from the middle, nor
could it be called more or less heavy. It is necessary, there-
fore, to have two means, one light, and which may be moved
from the middle upward, in respect of which it is heavy, and
is called air ; the other heavy, and tending to the middle, in
respect of which it is light, which is called water. There are,
therefore, four elements, fire, air, water, earth. There cannot
be a fifth for the same cause, that there cannot be only one
mean. But if any one will desire to establish five, his senses
and experience disprove it." *

He endeavours to establish a difference between the pure fire
and the common drudge of life, and quotes Scaliger to support
him, but in neither of them do we find any distinct ideas of
what these difi'erences consist. We are confounded by the great
part which hot, cold, moist, and dry, have to play, and it

* Danielis Sennerti Vratislavien&is Epitome Naturalis Scieniiae, Oxoniae,
J 632. Page 185.

HISTORY OF THE ATOMIC THEORY. 131

never occurs to them that hot air is air and heat, and that moist
air is air and moisture, but they are qualities put on by air at
will, or at command, by accident, by growth, by motion, or
by life. The qualities of the elements are not substantial
forms, but accidents; the original first matter forms the
elements which put on various forms, and so perform everything
that elements have the power of accomplishing. The changes
are performed by generation, fermentation, and corruption.

Baume, a believer in the four elements and phlogiston,
in 1773, says, that it is of no advantage to consult the
ancient chemists, they are so ambiguous ; and says : * —

" Is it not probable that nature combines the elements in a
direct manner by twos and twos, and by threes and threes, by
means absolutely unknown to us ? If these simple combinations
exist, they will be secondary principles, or principles made
from principles (principes principles), of which nature makes
use to form compound bodies. Knowledge, on this subject,
entirely fails. We have no information on the immediate
combinations of the four elements ; we only know that they
have such a disposition to mix, that it is impossible to have
them perfectly pure and isolated from each other."

We have here an opinion freed from the shackles of salt and
sulphur, but not beyond the early times, and I think not so
penetrating, although as practical as Roger Bacon's.

It will be interesting here to quote Bishop Watson,
a man who brought into chemistry more common sense
and less pretension than many less penetrating observers.
Speaking of elements, he says, ** by chemical elements,
which are the last products of chemical analysis, we are to
understand, not very minute indivisible particles of matter,
but the simple homegeneal parts of bodies which are not
capable, as far as our experience teaches us, of any farther
resolution or division, except in a mechanical sense, into

• Page 1 10, Vol. I., of" Chymie Experimentnlc ct Raisonn6e."

132 MEMOIR OF DR. DALTON, AND

similar parts, less and less, without end, as water into vapour,
more or less, subtile and attenuated. Aristotle and his fol-
lowers esteemed earth, air, fire, and water, to be elements,
simple and uniform in their several kinds, essentially distinct
and utterly incapable of being converted into one another, yet
easily uniting together, and by their different arrangements,
and properties and mixtures, composing every body in the
universe. Many modern chemists have adopted this idea;
others have increased the number of elements, by adding a
saline principle ; others have contended that some of these
elements, air and fire for instance, are themselves compound
bodies ; and others, lastly, are persuaded, that there is only
one elementary homogeneal principle, and that all the varieties
of bodies, as well as of what are most commonly esteemed
elements, ought to be attributed to the different magnitudes
and figures of the particles composing them ; and as the com-
ponent parts of water or air, or any other body, are by no
means supposed to be elementary particles of matter, but to
be made up of different numbers of elementary particles,
arranged in different forms, it may be thought probable, that
mechanical causes may either diminish or augment the
number, or change the disposition of the particles, and thus
effect the several varieties observ^able in nature.

" It would be improper in this place to enlarge on a sub-
ject, concerning which both ancient and modern philosophers
have been so much divided in opinion. Their great diversity
of sentiment may suggest a suspicion that the full compre-
hension of it does not fall within the reach of the human
understanding. The following observation may, perhaps,
tend a little to illustrate this matter. Let us suppose that
this terraqueous globe was not surrounded with any air or
atmosphere, and that by an approach to the sun, or an in-
crease of subterranean fires, by some means or other it should
become exposed to a heat four times greater than the medium
heat of summer, which we may reckon to be about 60 degrees

HISTORY OF THE ATOMIC THEORY. 133

of Fahrenheit's thermometer ; then would an atmosphere be
quickly formed around it, all the water on its surface, most
of the juices of plants and animals, and a great variety of
mineral particles, would be raised up in vapours and exhala-
tions, and whilst the heat continued would be kept suspended
in an elastic state, and constitute an atmosphere analogous,
as it may reasonably be imagined, to the chaotic state of our
present atmosphere, only differing from it in this, that it
would require a greater degree of heat in order to keep the
particles of matter from coalescing into one heterogeneous
mass. Again, in the present state of the atmosphere, suppose
that a great degree of cold should continue unabated for any
length of time, all the water on the surface of the earth would
be changed into a solid transparent stone, which might be
dug out of its quarry, and then employed in building as well
as marble, or any other species of stone ; all the particles of
air would be brought closer together ; some of them which
were the least elastic would be reunited : and imagining the
cold to be indefinitely increased, what reason can there be
against supposing that the whole atmosphere would be re-
duced into a solid state, forming a heterogeneous crust on
the surface of the earth ; the thickness of this crust, sup-
posing it to be as dense as marble, would be about four
yards? It will easily be understood, that water, and air, and
earth are, upon this hypothesis, but variations of the same
element introduced by heat.

** That the atmosphere which surrounds the earth was
originally formed from the chaotic mass, by having the more
subtile parts of which that mass consisted, elevated and put
into an elastic state by means of heat, seems not altogether
improbable. We find the atmosphere or firmament immedi-
ately succeeding the formation of light ; now, if the effect of
that light was heat, be the form or matter of it what you
please, then would such particles of the shapeless jumble as
were capable of being evaporated with that degree of heat.

134 MEMOIR OF DR. BALTON, AND

be elevated in an elastic state, and a division or separation
would be made in the midst of the great abyss, between the
waters which were of a nature subtle enough to be converted
by that degree of heat into an elastic fluid, constituting the
firmament or atmosphere, and the waters which could not be
evaporated in that degree of heat, but still remained cover-
ing the surface of the globe, being not collected into one
place, that the dry land might appear, till the third day.
This notion of the atmosphere and its formation, seems to be
conformable enough to Newton's opinion expressed in his
letter to Mr. Boyle. " I conceive the confused mass of
vapours, air, and exhalations, which we call the atmosphere,
to be nothing else but the particles of all sorts of bodies of
which the earth consists, separated from one another and
kept at a distance by the said principle," a principle of re-
pulsion." *

Here we have the one element again or matter treated simply
as matter generally, in the same way in which metaphysicians
have dealt with it, leaving heat and, probably as by others ex-
pressed, some general plastic power to form all the modifications.
This is much too indefinite for science, and it is surprising
that it should have been deemed sufficient even in Bishop
Watson's time. There is no attempt to examine the degree of
heat which may convert a solid body into a permanent
gaseous one, and no difficulty perceived in the persistence of
the atmosphere in a gaseous state whilst exposed to no more
cold than the solid or liquid substances around us, or the
persistence of the water in a liquid state, or the permanency
of the earth, why it did not occasionally send off rocks into
vapour or rarefy them into air ; nor is there any attempt to
find what strange powers may cause the diversity of struc-
ture. Although not expressed, these words were evidently

* Chemical Essays. By R. Watson, D.D., F.R.S., &c. Vol. I., p. 100.
4th Edition. London, 1787.

HISTORY OP THE ATOMIC THEOET. 135

written under the idea that the powers of nature worked
rather arbitrarily and capriciously ; how, is not distinctly
seen. When the mixture of pure elements is spoken of as
forming all bodies, there is a reason given clear enough for
the changes, and the chief blame attached to those who
believed in this is, that they did not obtain the amount
of each needed to form any one distinct substance. This
proves, as it appears to me, that they held their opinions
by a very slender tie.

Boscovich, in his theory of natural philosophy, in 1759,
gave the fullest scientific expression of the unsubstantial theory
of matter, which may be called the dynamical. The book is
not common, and not to be found in this neighbourhood. I
shall take Dr. Daubeny's description : ** He supposes that
matter is made up of a number of unextended indivisible
points, which, however, never touch each other, owing to the
mutual repulsion subsisting between them, so soon as they
come within a certain distance of each other ; which repulsion
increasing gradually in proportion as they are made to
approach nearer and nearer, becomes at length too powerful
for any force to overcome." *

In this theory we have again revived in another form the
idea that all matter comes from a non-material, or what we
may call a spiritual force, nor is it easy for us to conceive how
it could have any other origin. It is a revival of the doctrine
of the mind and of the soul being the origin of matter, or of
the early opinion that numbers were the true beginning, or in
other words, abstract forces. But we have to do with matter
when it is formed, not with its production ; and when these
unextended points have obtained existence, we are obliged to
reason on them as if real. One result, however, affects our
subject, that by this theory, matter may cease to be infinitely

• An Introduction to the Atomic Theory. By Charles Daubeny, M.D.,
F.R.8., &c. Second edition, Oxford, 1850. p. 34.

136 MEMOIR OF DR. DALTON, AND

divisible. It does not of necessity cease to be so, as we may
readily believe, in the constancy of these points ; but we may
also imagine the power dispersing in various directions, and
the absolute amount of force existing in one particle to lie
diffused throughout the whole world, or any given amount
of space.

When the particles are formed, Boscovich deals with
them exactly as with matter, formed of indestructible atoms.
" Thus he supposes that the points of matter alternately
attract and repel each other, according to the distance that
separates them, until they either come very close to, or
are removed to a comparatively great distance from each
other; in the former case they are repelled, in the latter
attracted; the former force preventing mutual contact, the
latter, which, when considered as acting between the earth
and bodies upon it, is no other than gravitation, drawing
them all together."

The Encyclopedie Methodique* in an article written by
G. Morveau, 1786, may be presumed to give the advanced
opinion of chemists. He says,

" Are there really different degrees of saturation of the same
salt ? or is not the union which it contracts with that portion
which exceeds the point of saturation, the effect of super-
composition, as in combination with a third foreign body?
This is a question which merits all our attention, not only
because it is of interest in the general theory of chemical
attraction, but rather because it is of importance that we
should understand what is the character of the affinity before
we attempt to submit it to calculation, or evejn deduce a satis-
factory explanation of the phenomena which depend on it. I
confess that the idea of divers degrees of saturation of one
body with another appears to me repugnant to all the notions

• Vol. I., p. 660-1. Encyclopedie Methodique. Chymie Pharmacie et
Metallurgie. Paris, 1786—1815.

HI8T0BY OF THE ATOMIC THEORY. 137

we have hitherto acquired of the method by which combina-
tions are formed. I can readily conceive that the point at
which water is saturated with a salt may change according to
the temperature, and that cold water may absorb more of the
gaseous acid ; the increase or diminution of the matter of
heat in the solvent changing the respective disposition, the
density, and perhaps the figure of the molecules, it is not
astonishing that the attractive force should be modified by
these changes ; that they should result in a contact more or
less perfect, and that the power of affinity should be able by
this means to protect from (the influence of) the law of gravi-
tation a greater quantity of matter, in the one case, than in
the other ; but we have nothing of this kind in the hypothesis
under consideration ; the circumstances are the same ; the
point of saturation cannot change, because it is the effect of
a cause which does not change.

" To make this clear, let us ask what is saturation ? Every
chemist will say that he understands by it the condition in
which a compound is, when neither of its constituents can
receive or retain in combination a greater quantity of the
other. Such is the rational and necessary acceptation of the
word saturation, otherwise it becomes void of sense ; then to
suppose, preserving this acceptation, that a substance may
be saturated with different quantities of the same substance, is
really to affirm two contraries."

" * * * * Now, when a new quantity of any of their
principles is added to one of these perfectly neutral salts,
there is nothing to prevent an attraction between them, and
even in a degree capable of producing solution, combination,
or affinity ; but it must be remarked that this affinity is not
that of an acid to a base, or a base to an acid, but of the
neutral compound, with the portion that was added; whence it
follows ; 1st, that it has no effect on the previous composition
which remains in its integrity, as if the neutral salt were super-

T

138 MEMOIR OF DR. DALTON, AND

compounded with a foreign body ; 2nd, that the point of
saturation is not changed ; and 3rd, that the power which
unites this portion which is added to the neutral salt, may be
much weaker than that which unites the same substance to
the same, at the point of saturation, without causing a con-
tradiction."

Page 566. " I shall terminate this section by a short
resume of the principal characters, which are capable of form-
ing a methodic division of affinities, and which may have been
lost sight of in the course of the preceding discussions.

" 1st. Two bodies of the same nature, whether simple or
compound, may unite and form a third, as homogeneous as
either of the two before the union. This is called affinity of
aggregation,

** 2nd. Two bodies of a different nature, simple or com-
pound, may unite without undergoing any change in their
first composition, if they are compound. This is called affinity
of composition.

" Two out of three bodies may shew a preference and com-
bine, leaving the third at liberty ; these bodies may either be
simple or compound, provided their composition does not
change, and they are found in a condition favourable to
contact. This is still affinity of composition ; whether the
three bodies have been put separately into the mixture, or
two been previously united, whilst the superior affinity of
the third has destroyed their union, by what is called pre-
cipitation.

" Three or more bodies, exposed to contact, may unite in
such a manner as to form only one homogeneous mass.
This is nevertheless affinity of composition, although two only
unite at first, and a third is added to the first two, and so
on successively.

«* 3rd. Two bodies incapable of combining, become so when
one or the other has either been decomposed or supercomposed.

HISTOHY OF THE ATOMIC THEORY. 1 39

In this case, the affinity of composition, which produces the
union, takes the name of disposing affinity.

"4th. Two or more compounds being placed in circum-
stances, suitable for bringing into play the respective affinities
of their component parts; either there is a change and new
products formed without our being able to determine which
is the most powerful affinity under which they act, or the first
composition remains, contrary to the order indicated by the
superior affinity of the principle of one of the component parts
to the affinity of the other. In these two cases we say that
they are not the relations of affinity of one body to another,
but affinities of concourse, otherwise called double affinities;
in a word, the sum of all the united affinities which are needed
to explain these phenomena.

" Two bodies being put in contact, the compound which
results is supercompounded, or united with an excess of one of
the principles. This tendency to supercomposition, is some-
times so strong, that when the least affinity of a third body
interferes with it, the proportions of the first compound are
changed, and the neutral state destroyed. This tendency may
cause the production of crystals, with excess of base, in an
acid liquor. To distinguish this force, we shall call it the
affinity of a compound for an excess of one of its constituents,
or for shortness, affinity of excess ^ which will be enough to
recall the idea when it has been well grasped. However
paradoxical some of these propositions may appear, I have no
fear of their being called in question after the proofs I have
given ; and if they are well founded, it will readily be granted
that they ought to form one of the most important elements
in the calculation of affinities."

Here now we have what Morveau has given, as the most
certain of the laws of affinities known among chemists at his
time. He adds, however, that they certainly scarcely deserve
the title. The following are additions : —

140 MEMOIR OF DR. DALTON, AND

* ** 1st. There is no chemical union, if one of the bodies be
not sufficiently fluid to allow the molecules to obey the law of
affinity, which carries them from (mere) proximity to (actual)
contact.

"2nd. Affinity takes place only among the smallest integral
molecules of a body.

" 3rd. From the affinity of one substance with another, we
cannot know the affinity of a compound; we cannot know the
affinity of a compound of one of these substances, with one or
the other in excess.

" 4th. The affinity of composition has no efficacy, unless it
can overcome the affinity of cohesion.

" 5th. Two or more bodies, which unite by the affinity of
composition, form a substance which has new properties
distinct from those which belong to each of the bodies before
combination.

"6 th. To give effect to affinities, a particular temperature
is necessary, which renders the action either slow or rapid,
invalid or efficacious."

These feeble and incipient attempts at laws may surely sur-
prise us, written as they are almost within the memory of some
of the living. There was at this time an attempt to measure
the force of affinities as the only method of obtaining
results, and there was not yet seen the absolute necessity of
having bodies kept uniform by a constant and absolutely
similar composition, much less to bring this absoluteness of
composition under the forms of natural law, and we might
add also, logical necessity.

It should be noticed that the remarks about saturation
shew that compound proportion was not in the least degree
understood in the present sense. Its possibility is even
denied.

The aim was to find the strength of affinity. When it is

• Remarks in italics on the various laws, from p. 567 onwards.

HISTORY OF THE ATOMIC THEORY. 141

said that we cannot find the affinity of a compound from
knowing that of its parts, it refers to affinity dynamically ;
no hint is given as to the knowledge of this amount
quantitatively. Proportion generally may be said to be
excluded.

Although these opinions give a pretty fair idea of the state
of the chemical mind at the several dates, we must return to
an earlier date again to follow up another direction.

142 MEMOIR OF DR. DALTON. AND

CHAPTER VII.

PHLOGISTON PERIOD AND PROGRESS OF THE BALANCE.

In the 17th century innovations were beginning in chemistry,
as we have already seen, but as usual, these did not all take
one direction. Van Helmont put his little archaeus, a kind
of intelligent agent, but with less independence than that
of Paracelsus, into the stomach, to do the work which he
could find no way of accomplishing by merely physical
means. Thus things began a new mystical direction. Becher,
in the Physicae Suhterraneae, ridicules his archaeus and
chimeras, and the whole host of " impudent chemists" also,
who assert that they obtain salt, sulphur, and mercury, from all
bodies, even animals and vegetables. He does not hesitate
to call these the greatest falsehoods. He calls " elements the
genuine and true things of which bodies consist, and from
which others are made and prepared." * But as he held on
by the four elements, we are not able to find in him much
material.

He had the merit of raising inquiry in a high degree, and
of bringing forward his great admirer, Stahl, who introduced
phlogiston. In this chapter we have a class of men who have
made another advance in experimenting, and whose works are
the first which living chemists can, without difficulty, peruse.
The advent of oxygen into science was preceded by a century
of vague prophesyings. The use of the balance was becoming
general, but men had no idea of the accuracy with which
nature weighed, although they had long used the proper
principle of making the earth the arbiter, by trying which
side of the scale she drew most willingly towards her. They

• Phys. Sub. Lib. i., sect, iii,, cap. i., No. 12.

HISTOEY OF THE ATOMIC THEORY. 143

had no idea of the fineness of her touch, and her absolute
refusal to make any allowance for inaccuracy in the construc-
tion of instruments. It was not even known that all bodies
could be compared by their weights ; why should they not as
well be known by their lightness? This plan had its fair
trial. By a curious circle of reasoning, it was decided, that
what we call oxygen, which makes an oxide, or calx of a
metal, was sulphur ; afterwards it was the principle of com-
bustion ; not such an erroneous idea. Now oxides or earths
were, of course, simple bodies ; when they were reduced to
metals in the fire, they combined with phlogiston ; they be-
came lighter. Therefore phlogiston had the principle of
lightness in it. The rule generally is, that we should begin
wrong. We now say the metal is simple, and by uniting with
oxygen, it becomes a compound, and is heavier. As the metal
burns and gives out heat, they said it gives out its phlogiston,
and loses its principle of lightness.* Stahl calls it sulphur.
This would scarcely come under our view had it not been the
cause of so many inquiries in the same direction, as to bring
about a result, derived from an analysis of all the oxides, and
a careful comparison of the weight of the metals, with the
weight of the oxides, whether produced by combustion or
oxidation in the fire, or precipitated from their acid solutions.
Even this strange theory tended in the right direction, although
at first threatening to take a mystical course. We could
scarcely have anticipated this difficulty of proving that all
bodies have weight and not lightness, but our forefathers
encountered it, and it may yet come to the struggle again,
renewed in a higher form, when we have to deal with those
physical existences, now called imponderables.

I am not aware that any one went into the subject with
care before Bergman. He may be said to have introduced
modern analysis. Before him analyses were not superior io

* p. 277. •• Traile de Soufre" Traduit de I'Allcmar.d de Stahl. Paris, 1767.

144 MEMOIR OF DR. DALTON, AND

those speculations about the constitution of bodies which in
former chapters have been passed over. I may indeed cite
here Roger Bacon's syntheses of bodies from the four elements,
as the earliest examples of an endeavour to shew how so many
bodies can be formed from few elements, and on the other
side, as the fullest example I know of early analysis, and
perhaps the very first in which numbers are used in connection
with elements. They are intellectual strivings after quanti-
tative analysis.

" There is, therefore, one different kind where fire and air
are greater ; 2ndly, where fire and air are less ; 3rd, where
fire and water are greater ; 4th, where fire and water are less ;
5th, where fire and earth are greater; 6th, where fire and
earth are less; 7th, where air and water are greater; 8th,
where air and water are less; 9th, where air and earth are
greater; 10th, where air and earth are less; 11th, where
water and earth are greater; 12th, where water and earth are
less ; and so you have two diversities. Next you have three
diversities; 1st, where fire, air, and water are greater; 2nd,
where fire, air, and water are less ; 3rd, where air, water, and
earth are greater; 4th, where fire, water, and earth are
greater; 5th, where air, water, and earth are less; 6th, where
fire, water, and earth are less; and in this manner, if you
divide those methods, you obtain from the first 16, from the
second 64, from the third 47> from the fourth 18, in all 145.
I will now speak of the fourth diversity, fire much, air less,
water much, earth less ; second, air much, water less, earth
less, fire less, and so being ingenious, you may draw out all
these diversities to light."

A manuscript copy of Dr. CuUen's lectures in 1762-3 in
the laboratory of Owens College, Manchester, from the late
Dr. Henry's library, mentions four elements, which, by
simple combination, could be formed into seven, but any
proportionate combination to account for the number in
nature, is not given.

HISTORY OP THE ATOMIC THEORY. 145

These lectures shew him to have been an exceedingly clear
and rational expounder of science. With good common sense
he waits for more knowledge when science fails, fully shewing
why he became famous, although he published very little.
Reasoning on the state of things at the time, he sayg, " It
appears, then, that we know of no physical element, nor any
chemical principle, nor are we acquainted with any body which
has fixed and permanent qualities."

He afterwards adds, " Having laid down and demonstrated
this fundamental proposition, viz., that the changes of the
qualities of bodies are all of them produced by combination
or separation, I now proceed to inform you that combination
depends upon attraction^ that is, the attraction of cohesion,
whereby the small particles of bodies very near each other are
disposed to approach, and in a certain contiguity to remain
coherent together."

He then goes on to explain simple elective attraction and
double elective attraction by diagrams, like those below,
where the lines ought to be drawn straight from C to B, and
from A to D. This appears to be earlier than Bergman, who
at that time had published nothing on chemistry. I can find
no internal evidence of their being written later than they
profess to be, the binding itself being old.

Dr. Cullen was professor of chemistry at Glasgow, and
Dr. Black attended his lectures, before being appointed his
successor, on the removal of Dr. Cullen to Edinburgh, in
1756. In the Annals of Philosophy, Vol. III., p. 554, Dr.
Thomson says : — " My knowledge of Dr. Cullen's opinions
was derived from the late Professor Robison, of Edinburgh,
who had the means of information, and, as he was a particular
friend and great admirer of Black, is entitled to credit. Now,
he informed me that Dr. Black's explanation of double de-
compositions, which he annually gave in his class, had been
originally broached by Dr. Cullen. This was the circum-
U

146 MEMOIR OF mi. DALTON, AND.

Stance that induced me to broach Dr. Cullen's name along
with Black and Bergman.

n* * ♦ As to Dr. Black, I consider myself as acquainted
with his opinions, because I attended his lectures ; and there
are thousands in Great Britain who did the same, and who
cannot but recollect the facts that I shall state. Dr. Black
taught that bodies combine in definite proportions, and he
explained double decomposition by means of diagrams, not,
indeed, the same as those of Mr. Higgins, but much simpler
and more elegant. I have been informed by Prof. Robison,
that he employed these diagrams from the very beginning of
his career, as a professor. One of them is given in page 554,
Vol. I., of his printed lectures. I have no doubt that all
similar diagrams, published in London, by Fordyce, &c.,
were derived from the same source. Now, could the doc-
trine of definite proportions be taught, and could double de-
composition be explained in this way (I quote Dr. a b
Black's explanation), let the bodies A and B be O 10
united with a force, 10 ; and the bodies C and D
with a force, 6. Suppose the attraction of A for
C to be 8, and that of B for D to be 9, if we mix # 6 O
these bodies, A will unite with C, and B with D. c d
To me they conveyed just as much of the atomic theory as
the perusal of Mr. Higgin's book did."

Dr. Robison edited the lectures of Black in 1803, and in a
note gives the above diagram and some judicious remarks,
shewing, at the same time, that although definite proportion
"was taken for granted, no general law to account for it had
been given.

But the question cannot be as to whether Dr. Cullen
discovered the atomic theory, (indeed, this extract might
have been brought on somewhat later), but whether Dr.
Cullen had so far advanced our knowledge of matter as to be
the first who gave out the ideas of single and double elective
attractions, such as have been attributed to Bergman.

HI8T0EY OF THE ATOMIC THEORY. 147

A note gives a fuller account of Dr. Cullen's views ; it was
written in the year 1759. Elective attractions were in reality
definitely laid down and presupposed in Geoffroy's tables;
but the investigation and elaboration was needed.* At pre-
sent we must consider Dr. Cullen as the first who used the
words and explanations in the manner afterwards made so
famous by Bergman.

• Note E., p. 45., Culleo's Life, by Thomson, p. 570. Appendix — The
following passages from a letter, written by Dr. Cullen to his friend and former
pupil. Dr. George Fordyce, of London, in October, 1759, contains bis own
statement of his views with regard to double elective attractions. " I must
give you the manner of considering the subject, which I fell upon last session,
and shall continue to employ as the most easy and simple. I begin with your
third and fourth cases, and to these one general rule applies, viz., that when
two mixts (compounds) are applied to each other, if in each mixt there is a
substance, that from the table of elective attractions, is by itself capable of
decomposing the other mixt, the attractions between these substances and the
substances they attract in the opposite mixt, must always be greater than the
attractions subsisting in the mixts applied to each other ; and therefore, &c.
Thus, if nitrum argenti and common salt are applied to each other, as by the
table of elective attractions, the nitric acid in nitrum argenti, is by itself
capable of decomposing the other mixt, common salt ; and the muriatic acid in
common salt is capable of decomposing nitrum argenti: the attractions between
the nitric acid and the soda, with the attraction of the muriatic acid and the
silver must be always greater than the attractions subsisting in the mixts,
nitrum argenti and common salt, that were applied to each other. This I
illustrate by the diagram adjoined. Let there be two rods intersecting one
another, and moveable on a common axis at the point of intersection. At the
extremities of each let there be placed substances that have an attraction for
each of the substances on the extremities contiguous to them, and let the
attractions be expressed by the letters W, X, Y, Z. The rest of the illustra-
tion will readily appear from the diagrams.

Nitric W SUver. Nitric W SUver

Add.

. Muriatic
Soda. X Acid. Mercury. X

Y 7 X and Z 7 W by table. Y 7 X and Z 7 W by table.

Ergo Y + Z 7 X + W Ergo Y + Z 7 X -h W

You see that the prevailing attractions are here determined from the table
of single elective attractions.

We are now come to the only difficulty in the affair of double elective
attractions in instance past. To this our general rule does not apply.

148 MEMOIK OF DK. DALTON, AND

There is no doubt tliat, however these opinions might be
at the time floating amongst chemists, the works of Bergman
were both the fullest and the most important on this subject.
From them I shall give rather long quotations. *

" On the different amount of phlogiston in metalsjt he says;
calces (oxides) do not displace each other, as experience shows,
at least, not in the same order as the metals do. May not
therefore the quantity of reducing phlogiston in any metal be
determined by a comparison of the weights of the precipitated
and the precipitating metal? The following experiments will
show the answer, but let us first examine, in a general way,
those cases which may possibly occur : —

" Let A be the precipitating metal, m the weight of acid
necessary for dissolving 100 of A, x the quantity of reducing
phlogiston in 1 00 of ^ ; B the metal to be precipitated, nm
the weight of the solvent mentioned necessary for dissolving
100 B, and y the amount of reducing phlogiston in 100 jB. n
may be equal to unity, or it may be more or less than unity."

" Let, I., n = 1 then m = nm"

(In other words, if w = 1 the quantity of acid necessary for
dissolving the precipitating metal, it will be equal to the
quantity necessary for dissolving the precipitated metal.)

" In this case, i( x = y there is no difficulty, because the
solvent of each dissolves an equal weight, and B is able to
take from A as much of the inflammable material as is neces-
sary for its reduction.

See how it comes out when my new scheme is applied to it. Y and Z are

by the table of elective attractions each of them less Vitriolic w Soda.

■' Acid. "^ >•

than W, but greater than X. If, therefore, Y and

Z are exactly as much greater than X, as they are Y

less than W, the four attractions would be exactly

balanced ; but if Y and Z exceed in any degree more Silver. ' X

than they fall short of W, than Y -f- Z must be greater than W -f- X.

• Torberni Bergman, Opuscula Physica et Chemica, pleraque ante seorsim

edita, jam ab auctore collecta, revisa et aucta. Holmiae, Upsaliae Aboae, &c.

Vol. I., 1779, II., 1780, III., 1780, IV., 1787, V., 1788, VI, 17no.

t Vol. III., p. 1.36.

HISTOBY OF THE ATOMIC THEORY. 1 49

" If X is greater than y there appears still no obstacle to
prevent complete precipitation.

" But if X is less than y, so that only a part of B can be
displaced, a portion of the dissolved precipitant must be
sensibly thrown down, so as to act anew, or some other
assistance must be given.

«' II. Let n 7 I et m Z. nm

** With respect to phlogiston, this is the same result as in
case I., but the obstacles are less."

(That is, if the acid for dissolving the precipitating metal
is less than the acid which dissolves the metal to be precipi-
tated, as in this case, the precipitating metal would not cease
its action for want of acid.)

"III.) Let n z. 1 then is m 7 nm. In this case B cannot
be entirely thrown down, unless nx =^ y or nx 7 y, because
only n 100 of the precipitant A is dissolved."

(That is, if it requires more acid to dissolve the precipi-
tating metal than the one in solution, then the metal in
solution cannot be quite thrown down, unless it should be
found that the amount of phlogiston in the precipitant is
equal to the amount in the precipitate, or greater than it.)

Then, after recounting experiments, the first of which are
made with a nitric acid solution, he says, p. 139 ;

" Therefore 135 parts of mercury have reduced completely
into the metallic form by means of their phlogiston, 100 parts
of silver which had been dissolved and calcined. This had
united with four times its weight of mercury, and crystallized
in an arborescent form.

" The amount of lead necessary for precipitating 100 lbs. of
dissolved silver, amounts to 234 lbs. *♦»*♦*•

" C. 375 lbs. of shining plates of copper were put into a
solution of silver, and were soon covered with a crystalline silver
coating. When all the silver had fallen, the copper plates,
when well cleaned, were found to have lost 31 lbs. The pre-
cipitated silver was found to amount to a cwt. (100 lbs.)

150 MEMOIR OF DE. DALTON, AND

" In order to examine into the power of different solvents,
we precipitated with copper a hundredweight of silver, which
was dissolved in vitriolic acid, but there were only 30 lbs. of
copper used. This, then, enables us, to some extent, to
measure the great avidity with which nitric acid seizes on
phlogiston, so much excelling the vitriolic acid."

The amount of each metal needed to precipitate 100 lbs. of
silver, is given with the experiments, but to save room, I add
a list.

"135 tbs. Mercury dissolve 100 lbs. of Silver.

234 „ Lead ditto.

♦ 31 „ Copper (with nitric acid) ditto.

30 „ (with vitriolic acid) ditto.

29 „ Iron (with vitriolic acid) ditto,

88? „ Tin ditto.

Bismuth could scarcely be determined.

64 „ Nickel ditto.

92 „ Arsenic ditto.

37 „ Cobalt ditto.

55 „ Zinc ditto.

83 „ Antimony ditto.

51 „ Manganese ditto.

Amounts of zinc used to precipitate 100 lbs. of metals.

217 tbs. Zinc precipitated 100 lbs. of pure Gold.

416 „ „ ditto Platina.

44 ,, „ ditto Mercury.

26 „ „ ditto Lead.

164 „ „ ditto Copper.

68 „ „ ditto Tin.

49 ,, „ ditto Bismuth.

70 „ (the solution was difficult) ditto Antimony.

Scarcely any precipitation appears with Iron."

Then, at p. 150, there are certain corollaries, of which the
following sentences suit best the subject in hand : —

COROLLARIES.

*' A. That dephlogisticated metals unite with different acids
in a variable manner (t. e., that different amounts of metal unite
to different acids). Thus, 100 parts of silver, dissolved in

t

HISTORY OP THE ATOMIC THEORY. 151

nitric acid, are reduced by 31 of copper, but if united to vitriolic
acid, they want only 30 of copper. In the same way 100
parts of copper, in a vitriolic solution, are restored to a metallic
form by 146 pounds of zinc, but in a nitric acid solution, 164
lbs. of zinc are wanted. Therefore nitric acid dephlogisticates
the metals most, vitriolic acid less, and muriatic acid still
less.

*•*• B. Since we added the solutions in a saturated state, it is
clear that the mutual quantities of phlogiston in the precipitate
and the precipitant are in inverse proportion to the weights.
Let the quantity of the phlogiston in a hundredweight of
silver be 100, and the amount in a hundredweight of mercury
will be 74, in lead 43, in copper 323, in iron 342, in tin 1 14,
in bismuth 57, in nickel 156, in arsenic 109, in cobalt 270, in
zinc 182, in antimony 120, in manganese 196. * • ♦ •

" D. Let us see then how those principles before-mentioned
may be applied. With respect to silver, which answers to J5,
there is no precipitant or A^ which acts so as to make w = 1 .
If mercury or lead is used, then w 7 1 , but if copper, iron,
tin, bismuth, nickel, arsenic, cobalt, zinc, antimony, or
manganese is used, the case is w Z 1. In the zinc precipi-
tates « = 1 is also wanting. Gold, platinum, iron, and
antimony, make n 7 1, all the rest » Z 1.

" Page 155. According to the experiments produced, the
metals richest in phlogiston, are platina, then gold, iron, copper,
cobalt, manganese, zinc, nickel, antimony, tin, arsenic, silver,
mercury, bismuth, and lead, so that, in some order, it
approaches nearer to the first metal. The relative numbers
designating the amount found in each, are to be sought by
other methods. A trial of each of the metals, so as to obtain
the attractions sought for, would be a great labour, if done
with sufficient care and sufficiently repeated, but if the work
were divided it would be easier. If one would choose for
examination mercury, another lead, a third copper, and so on,
so as to see their relation with respect to the others, then we

152

MEMOIR OF DR. DALTON, AND

should have a series of experiments, which, if rightly com-
pared, would not only disclose the various properties of each,
worthy of observing, but would determine also the relative
quantities. In this way, if the absolute value of only one
were diligently sought out, all the rest would follow.

Vol. ii., p. 373. " The calces of metals have not that amount
of phlogiston which is necessary to the metallic condition, but
they are still found not entirely deprived of it.

" Metallic precipitates, when properly examined, reveal to
us various mysteries."*

" In the following table 100 parts of reguline metal are in
all cases understood to be dissolved : — f

100 parts of Gold with the aerated mineral alkali gave 106 of dry precipitate.

,, ,, caustic 110

„ ,, martial vitriol 100

,, Platina ,, aerated mineral alkali 34

,, ,, caustic 36

,, Silver ,, aerated mineral alkali 129

,, ,, caustic 112

,, ,, phlogist. (pruss. of pot.) •• 145

M „ saline 133

„ ,, vitriolated 134

,, Mercury „ aerated mineral alkali 110

,, ,, caustic 104

,, ,, vitriolated 119

„ Lead ,, aerated mineral alkali 132

,, ,, caustic , 116

,, „ vitriolated 143

>« Copper ,, aerated mineral alkali 194

,, ,, caustic 158

„ ,, phlogisticated 530

,, Iron ,, aerated mineral alkali 225

„ ,, caustic 170

„ „ phlogisticated 690

„ Tin ,, aerated mineral alkali 131

„ ,, caustic 130

„ M phlogisticated 250

• Page 390. f Vol. II., p. 390.

HISTORY OF THE ATOMIC THEORY. 153

100 parts of Bismuth with the aerated miueral alkali gave 130 of dry precipitate.

,, ,, caustic 126 „

,, ,, phlogisticated 180 „

,, ,, pure water 113 „

,, Nickel ,, aerated mineral alkali 13d „

,, ,, caustic 128 „

,, ,, phlogisticated 200 „

,, Arsenic ,, phlogisticated 180 „

,, Cobalt ,, aerated mineral alkali .... 160 „

,, ,, caustic 140 „

,, ,, phlogisticated 142 „

,. Zinc ,, aerated mineral alkali 193 „

,, M caustic 161 „

,, ,, phlogisticated 495 „

,, Antimony aerated mineral alkali 140 ,,

,, ,, caustic 138 „

,, ,, phlogisticated 138 „

,, Manganese aerated mineral alkali 180 „

„ ,, caustic 108 „

,, ,, phlogisticated 150 „

" Having compared the weights now produced, it is neces-
sary, first, to inquire into the cause of such differences."

***** Is it not then the matter of heat that is
attached to the calx, and which is always united to the caustic
alkali, for does it not excite heat when dissolved in the simple
acids ?

** This forms a triumphant foundation for assaying minerals
and metals in the humid way, the mere weight of the precipi-
tates being known. ♦ ♦ ♦ ♦ jf th^ game mode of
operating be used, the results of the experiments will be
always the same. Let us say that a quantity of metal a in
certain circumstances makes a precipitate of the weight of h ;
if the same method be used, it is obvious that nh may safely
be allowed to correspond to na of the perfect metal, although
in the fundamental experiment, the dissolved metal may not
have been completely precipitated, or its weight may have
been increased by foreign matter, still the same circumstances
will produce always the same gain or loss, and the conclusion

X

1 54 MEMOIR OF DR. DALTON, AND

will remain unshaken. Let then the methods be exactly
decided on, and no fallacy is to be feared." *

ON ELECTIVE ATTRACTIONS.

" Simple elective attractions.! Let A be the substance to
which a, b, c, &c., are drawn ; further, let A be added to c to
saturation, this we shall call Ac, when again b is added, let
the union take place to the exclusion of c ; then A is said to
attract b more than c, or b has a stronger elective attraction
than c; then Ab, when a is added, gives up b, and a is united
instead, then it is understood that a excels b in attractive
force, and the order of the efficacy of the attraction forms
a series «, b, c. What we here call attractions, others
call affinity; we use either term promiscuously in future,
although the latter being more a metaphorical expression
does not appear so suitable in physics.

* * * * Page 3 18. " It has not escaped me, that some
chemists have considered, as entirely without foundation, the
doctrine which asserts that neutral or middle salts can receive a
distinct excess of acid. That this sometimes takes place the
experiments to be related most clearly shew, although naturally
it (the excess) adheres with far less tenacity than that por-
tion which is necessary to effect saturation.

* * * * Page 325. " From all that has been brought
forward, I consider it clear, not only that the doctrine of a
decided superfluity of either ingredient is not absurd, but that
in reality this result is found in many cases. Certainly this
superfluity attaches itself much more loosely than the portion
necessary for saturation, so that frequently it is easily driven
off, but this in no way causes it to be less real."

Here we find Bergman endeavouring to obtain the amount
of oxygen in metallic oxides, or phlogiston in metals. He
finds that the amount in equal quantities of metals is not the
same. This could only be the case if the atomic weights of
all metals were the same.

♦ Page 396. f Vol. III., page 294.

HISTORY OF THE ATOMIC THEORY. 155

In agreement with this, he finds that the quantity of acid
necessary for dissolving certain weights of metals, differs with
each metal, and the amount which one metal precipitates from
the solution, differs with each metal. This was promising fair
for discovery ; and in the first table we have the amount of
various metals needed to precipitate 100 of silver, in fact, a
table of atomic weights, if he could have seen it, although
imperfection in experiment rendered it difficult, and the law
seemed very intricate.

He drew the conclusion that some acids dissolve metals
with more oxygen in their oxides than others, when he says,
1 00 of silver are reduced by 3 1 of copper in nitric, and 30 of
copper in sulphuric acid. This helped to lead him wrong.

He seems to have most naturally thought that it would be
needful to find the relation of the oxygen in a metallic oxide
to that in every other, and was naturally surprised at the great
labour needed. We know that this would be a most compli-
cated relationship, and that the oxygen is constantly changing
its per centage relation in every compound, to such an extent,
that it would be impossible to follow it without constant
recurrence to its atomic weight. We may look on this inquiry
of Bergman as a search, acute although unsuccessful after that
last step in simplicity.

He gives a valuable discovery in the establishment of the
permanence of the amount of oxygen in precipitated oxides,
the very foundation of analysis, and an important step towards
the knowledge of permanence of constitution in all substances
whatever. That the numbers need correction, need hardly
be remarked.

At the same time it seems to be beyond doubt that he did
not grasp with great clearness the doctrine of permanent con-
stitution, or he would scarcely have made these remarks on
neutral salts receiving a distinct excess of acid. Any indefinite
iimount added, becomes a mixture only.

He extended the tables of attraction to a great length,

156

MEMOIR OF DR. DALTON, AND

calling them elective attractions, preferring attraction to
affinity. His tables are 59 in number, the first portion giving
the wet waj^, and the second the dry. These were given in
the old symbols, and have certainly a most formidable and
unattractive appearance, in his original work. They have,
however, been published in England, at an early period, in
the form below.

SINGLE ELECTIVE ATTRACTIONS.

IN THE MOIST WAY.

SULPHURIC ACID.

NITRIC

J ACID.

MURIATIC

ACID.

Potash

Potash

Potash

Soda

Soda

Soda

Baryta

Baryta

Baryta

Lime

Lime

Lime

Magnesia

Magnesia

Magnesi

a

Ammonia

Ammonia

Ammonia

Alumina

Alumina

Alumina

Oxide of Zinc

Oxide of Zinc

Oxide of Zinc

„ Iron

,,

Iron

>>

Iron

„ Manganese

Manganese

„

Manganese

„ Cobalt

Cobalt

,,

Cobalt

„ Nickel

Nickel

it

Nickel

„ Lead

Lead

,,

Lead

„ Tin

Tin

»>

Tin

„ Copper

Copper

„

Copper

„ Bismuth

Bismuth

„

Bismuth

r, Antimony

Antimony

>»

Antimony

„ Arsenic

Arsenic

»

Arsenic

„ Mercury

Mercury

n

Mercury

„ Silver

Silver

,,

Silver

„ Gold

Gold

J,

Gold

„ Platina

Platina

>>

Platina

„ Water

Water

>>

Water

„ Alcohol

Alcohol

»

Alcohol

„ Phlogiston

Phlogiston

>'

Phlogiston

IN THE DRY WAY.

^ULTHURIO ACID.

NITRIC ACID.

MURIATIC

ACID.

Phlogiston

Phlogiston

Phlogiston

Potash

Barj

ta

Baryta

HISTORY OF THE ATOMIC THEORY. 1 5?

8ULPHUIUC ACID.

NITEIO ACID.

IfUaiATIC ACID.

Soda

Potash

Potash

Baryta

Soda

Soda

Lime

Lime

Lime

Magnesia

Magnesia

Magnesia

Metallic Oxides

Metallic Oxides

Metallic Oxides

Ammonia

Ammonia

Ammonia

Alumina

Alumina

He gave also two tables of his famous double elective
attraction, or compound attraction. The examples given are
numerous, and would take too much room. The form is
exactly the same as given below as Elliot's, no numbers
being used.

Elliot published Bergman's tables, with the addition of
figures, to show the relative force which one bore to another.
He says, " suppose that (see Encycl. Method. Diet, de
Chymie, vol. i., p. 552) potash and sulphuric acid attract each
other with the force of 9 ; that oxide of silver and nitric acid
attract each other with the force of 2 ; that the affinity of nitric
acid, with potash, is 8, and that of sulphuric acid, with oxide
of silver, 4. As 8 -f 4 is greater than 9 + 2, decomposition
takes place, and two new compounds are formed, nitrate of
potash and sulphate of silver."

He then made the symbols so : —

Nitre of Potash

(Potash 8 Nitric Acid

Q 9 f Nitre

of Potash) ^ ^ (of Silver

I

Vitriolic Acid 4 Calx of Silver

Vitriol of Silver

G. Morveau continued this schema or symboles, finding
new numbers, and he has put into a short table his results.
This is a more definite way of showing the relation of bodies
to each other than wc have yet seen.

158

MEMOIR OF Dll. DALTON, AND

Table of the numerical expression of the affinities of Jive Acids and
seven Bases, according to the constant relations indicated by the
most familiar observations.^

Baryta

Potash

Soda

Lime

Ammonia
Magnesia.
Alumina .,

VITRIOLIC

NITRIC

MURIATIC

ACETIC

CARBONIC

ACID.

ACID.

ACID.

ACID.

ACID.

66

63

36

29

14

62

58

82

26

9

68

60

28

25

8

64

44

20

19

12

46

38

14

20

4

60

40

10

17

6

40

30

10

15

2

At the same time he says,t relating to the figures, *' the
numbers which 1 have employed have no certain basis, but
because they ^gree with a sufficient number of the most
familiar observations, they may be used without inconvenience,
until we recognise the necessity of changing them, so as to
make them agree with other results."

Fourcroy gave numbers also on similar principles, but
Morveau objects to them as being so small that it was not
easy to find intermediate ones, whilst he objects to Kirwan's
numbers which gave the weight of the base as the amount of
the affinity, because this did not agree with results.

In these schemes of double decomposition there seems to be
a tacit agreement, that the acid which saturated one base,
would saturate the second.

Kirwan experimented very much in the direction which
Bergman had followed. He is another of those who nearly
discovered the atomic theory, who laboured in a legitimate
direction, but whose discoveries and theories on the subject
are merged in the higher and simpler law.

A brief extract will give his results.

*' The discovery of the quantity of real acid in each of the

mineral acid liquors, and the proportion of real acid taken up by

a given quantity of each basis at the point of saturation, led

mc, unexpectedly, to what seems to be the true method of

♦ Diet, de Chymic, Vol. I., p. 558. f T'age 557.

HISTORY OF THE ATuMit iiihuitY. 159

investigating the quantity of attraction which each acid bears
to the several bases to which it is capable of uniting ; for it
was impossible not to perceive, first, that the quantity of real
acid, necessary to saturate a given quantity of basis, is in-
versely as the affinity of each basis to each acid. 2ndly.
That the quantity of each basis, requisite to saturate a given
quantity of each acid, is directly as the affinity of such acid to
each basis. Thus 100 grains of each of the acids require for
their saturation a greater quantity of fixed alkali than of
calcareous earths, more of this earth than of volatile alkali,
more of this alkali than magnesia, and more of magnesia than
of earth or alum, as may be seen in the following table.

Quantity of Basis taken up ty 100 grs. of each of the Mineral Acids.

Yeget fixed
Xlkali.

Mineral
Alkali.

CaloareouB
Barth.

Volatile
AlkalL

Bfagnebia.

Earth of
Alum.

grs.

RTS.

grs.

gr"-

grs.

grs.

Vitriolic Acid... 215 ....

. 1U5 ...

... 110 ....

.. 90 ..

... 80 ...

... 75

Nitrous Acid ... 215 ....

.. 165 ...

... 96 ....

.. 87 ..

... 75 ..

... 66

Marine Acid.... 215 ....

.. 158 ..

... 89 ....

.. 79 ...

... 71 ...

... 55

" As these numbers agree with what common experience
teaches us concerning the affinity of these acids with their
respective bases, they may be considered as adequate expres-
sions of the quantity of that affinity, and I shall in future use
them as such. Thus the affinity of vitriolic acid to fixed
vegetable alkali, that is, the force with which they unite, or
tend to unite, to each other, is to the affinity with which that
same acid unites to calcareous earth, as 215 grs. to 110 ; and
to that which the nitrous acid bears to calcareous earth as 215
grs. to 96," &c.* He adds a similar table of metals and acids.
Kirwan gives here what would lead to the atomic weights
of the bodies had he known the law which appears to have
been first published by Richter; one obtained the atomic
weights as the measure of affinities, the other reciprocal

• Philosophical Transactions Abridged. Vol. XV., p. 386-6, year 1783.
This was read, I believe, in 176M.

160 MEMOIK OF DR. DALTON, AND

affinities, but neither knew the other's results, and both
were lost sight of. The one (Ritcher) did not know that
he had got close upon a universal law, the other (Kirwan)
did not know that he had got the mode of expressing that
universal law, but used it for what it was little worth, an
expression of affinity.

We now come to Wenzel, one of those men whose names
have been brought forward as a much neglected philosopher,
and to whom almost every writer on the history of science,
who has had occasion to mention him in later years, has
been anxious to award the due honour. We see his book con-
stantly quoted. Some writers give us his words, others give
us what appears such a clear explanation of his ideas that
we feel no more to be wanting. I had been long anxious to
obtain his works, but after advertising in Germany, and
inquiring in several towns and large libraries in this country,
as well as in France and Germany, I did not obtain the
volume, and proceeded without it. I afterwards found that a
duplicate copy existed at the Munich Royal Library, and was
fortunate enough to obtain it, duplicate copies being generally
disposed of. Having read it carefully over, I found no such
passages as are imputed to him ; and, therefore, read it still
more carefully again, and then a third time, but they did not
exist. Having written to two eminent historians of science
for an explanation, I find that neither had seen the volume;
but one of them informed me that the mistake had been
rectified in a supplement to the " Handwoerterbuch der
Chemie u. Physik."*

The reciprocal saturation which results when two salts
decompose each other, is the discovery, the honour of which
has long been given to Wenzel. It is a curious fact that not
only does he not see this, but he sees and explains the con-

• It is by Dr. J. S. C. Schweigger, and has been since published as a
pamphlet (Ueber die Stocchiometrische Reihen im Sinne Richter's), &c.,
Halle, 1853.

HISTORY OP THE ATOMIC THEORY. 161

trary, as lie shews us that in double decomposition something
always remains unsaturated ; but generally very little remains.
One is sorry that being so near a law, he had not the
slightest conception of it. The most important part of his
work, as far as our purpose is concerned, seems to me to be
contained in the following sentences. The title of the work
is "The Doctrine of the Affinity of Bodies."* I shall not
give the original, although scarce, as the work, from the fact
above stated, has lost its great importance.

In the Preface, he says, " at first my only intention was to
make for my own use a treatise which should contain the
order of the ascertained affinities and the circumstances under
which they acted, lest I should not be able to remember them.
But it occurred to me that others might find it useful also,
if it were more worked out. For this end I endeavoured to
explain the cause and the law of affinity on a good founda-
tion, and the circumstances under which the bodies combine as
well as the true relation of their weights towards each other.

Page 4. " It is of itself clear that any combination of bodies
must have a constant unchangeable proportion, which can
neither be greater nor smaller without some cause acting
externally, because, otherwise, nothing certain could be de-
cided on by comparing them. It therefore necessarily follows,
that every possible combination of two bodies stands in the
most exact relationship with every other, and this relation
expresses the degree of combination.

Page 9. " These smallest particles of each body have at all
times, in a natural state, a determinate figure; but the whole
mass of the body takes a form according as chance or art gives
it, without causing any change in the smallest particles, just
as the tender fibres or tubes in a piece of wood remain always
the same, although the whole piece may be in the shape of a
ball or a cube."

• Carl Friedrich Wenzel, Lehre von der Verwandschaft der Koerper.
Dretdeo, 1777.

Y

162 MEMOIR OF DR. DALTON, AND

Page 10. " I examine the natural structure of some metals,
1 see certainly nothing more than that they are hard solidly-
united heavy bodies, which become liquid in the fire at
different d^rees of heat, and lose their former connected-
ness (or cohesion), and without being heavier take up a
greater or less space than before. This is enough to enable
us to conclude that the figure of the smallest particles of
metals is changed by the fire, and that the fluid condition of
the whole mass, and its altered specific gravity, are the
necessary consequence of this alteration of figure. For
when the mass of a body without change of weight takes up
a greater or less space, it is certain that it can take place
under no circumstances except a change of figure in the
smallest portions of the bodies. A thousand small cubes may
be put into a smaller space than the same number of spheres
of the same mass and weight, and the heap made by the
spheres is not so great as if they were converted into stars,
and so on. When the specific gravity is altered, no matter by
what means, the figure and situation of the smallest parts can
no longer remain the same."

Page 20. " Besides change of figure, I know no sufficient
reason for all that has been said ; for if we completely banished
the figure, and viewed the properties of the body as something
substantial in matter, I know not how we could explain
without contradiction the every-day experience ; or we must,
as Snellius with refraction, explain it by the will of God,
which settles the matter at once ; but if my understanding is
to lay hold of the method by which anything acts, this expla-
nation will not be satisfactory.

Page 28. " But we have remarked that any combination
of bodies, on account of the figure of their parts, depends on
static laws, and there it is proved that the motion of a
weight is so much the slower the smaller the force is, in com-
parison with it. Let us apply this to the present case, and
bodies will appear to us as so many weights, and their com-

UlSTOKY OF THE ATOMIC THEORY. 163

mon solvent as a force, which acts more slowly or more
rapidly on one or the other. It follows, then, that the more
rapidly a common solvent unites with a body, the greater
must be its degree of combination, and we obtain therefore
this law.

" The affinity of bodies tvith a common solvent is in the
inverse ratio of the time taken to dissolve.

Page 31. "We have now a universal law, according to
which the affinity of bodies or their rank in the series is
decided, and we obtain at once this important advantage,
that we not only know that the union of a common solvent
is greater or less with any body, but also how much greater
or less it is, because the difference of the time of solution shews
the difference of the combination. Therefore amongst a number
of bodies, the combination of one with a common solvent may
be considered as a quantity which may be expressed by a
fixed number, if we take the smallest in such a series as unity ;
and by this means we are able to give a correct explanation
of all phenomena.

Page 46. " This important question, then, remains, why
a solvent, when it is only moderately diluted, does not in the
least attack certain metals, but as soon as another metal is
dissolved in it, with which it naturally has a less affinity, a
ready solution of the first takes place. Page 47. Because
here the powers meet which assist each other.

Page 72. " The circumstances under which this metal (iron)
is dissolved by vitriolic acid are these, that the acid must not
be strong. When both unite, iron vitriol is formed, which loses
the most of its acid in the fire, as well as by frequent solution
in water. A small bored cylinder of Styrian steel of 102
grains was put into half an ounce of the spirit of vitriol, diluted
with an equal quantity of water, exactly as with the zinc ex-
periments; there remained 46 J grains of steel, and 55 J grains
were dissolved in the half ounce of the spirit of vitriol.

164 MEMOIR OF DR. DALTON, AND

" Therefore the relation of the hardest steel to the strongest
vitriol is 175 : 240.

" Application of the doctrine of affinity of bodies,^ *' This
will best be shewn by examples.

** Is it possible by Beguin's spirit of sulphur (a sulphide of
ammonium chiefly) to decompose the luna cornua, or to
separate the muriatic acid entirely without loss ?"

" To settle this question we require only the following ex-
periments. Muriatic acid has a smaller degree of affinity with
silver than with the volatile salt. Sulphur, on the other hand,
unites with silver in preference to the volatile salt. The
silver is not separated from the muriatic acid by the volatile
salt, on account of accidental circumstances, but this separation
follows the moment any other body unites with the silver, if
it has not the property of dissolving the silver. But sulphur
is just such a body, and is^ therefore, fitted for the purpose.
If, then, the spirit of sulphur of Beguin is poured on finely
powdered luna cornua, it is easily seen that the muriatic acid
in the luna cornua must unite with the volatile salt in the
spirit of sulphur, and the sulphur will unite with the silver.
The new products that are formed by this separation, can
consequently be nothing more than common sal ammoniac and
sulphuretted silver.

Page 452. '' Another similar question arises by which the
proportions of the mixture must be considered. How much
cinnabar must be mixed with the luna cornua, so as com-
pletely to separate the silver ?

" The possibility of this decomposition may be shewn in
the same way as in the first case. If no particular experiment
is made, it depends on the comparison only of the following pro-
positions. Half an ounce of luna cornua contains ISOA grains
of fine silver. Half an ounce of fine silver takes up 35^ grains of
sulphur. We may then calculate that for I80t% grains of fine
silver, 26 1 grains of sulphur are required. We know besides,

* Page 450.

HI8T0EY OF THE ATOMIC THEOET. 165

that cinnabar contains sulphur in the proportion of 65 to 240
of quicksilver, or 65 grains of sulphur united with 240 of
quicksilver, are to be met with in 305 grains of cinnabar,
therefore 26 J grains of sulphur are contained in 125 J of cin-
nabar. This quantity of cinnabar, as regards its sulphur,
will be sufficient for the decomposition of half an ounce of luna
cornua,

; " But we must inquire if 125J grains of cinnabar contain
as much quicksilver as will be sufficient to take in the muriatic
acid which is saturated with the silver. Half an ounce of luna
cornua contains 53 tV grains of muriatic acid of greatest
concentration. In half an ounce of the caustic sublimate there
are 58^ grains of the strongest acid, which is saturated with
174 grains of quicksilver. From this proportion it is found
that 53 tV grains of the strongest muriatic acid are required
for 159l grains quicksilver. Now as there are in cinnabar
240 grains of quicksilver united with 65 grains of sulphur,
159f grains of quicksilver require 43 j} grains of sulphur.
Both together give nearly 202^ grains of cinnabar. Conse-
quently, from 125^ grains of cinnabar, all the muriatic acid
found in the luna cornua is not separated. We see from this
that the muriatic acid of the lunar caustic rises in sublimation
with the quicksilver out of the 202^ grains of cinnabar as a
caustic sublimate, whilst the silver remains united only with
80 much sulphur as it found in 125^ grains of cinnabar.'*

His smallest parts of bodies are not atoms, but molecules
rather, or particles, as they change their form.

He has made a theory of affinity, and attempted to repre-
sent the force by a number. To attempt to give the numerical
or dynamical ratio of every body to each other was an object
of the very highest kind, and we must look on him as one of
those less fortunate men who, when search was required in
every direction, has had the misfortune to have the wrong one
assigned to him. He searched in the direction of time, and
obtained a manifest fallacy ; as bodies are constituted abstractly

166 MEMOIR OF DR. DALTON, AND

he might be correct, but his theory cannot be introduced
into science at present, and in the way he introduced it, it
was entirely a mistake. But he has done great service in
early times in seeking for the distinct constitution of bodies,
and in asserting the constancy of combination ; whilst he
obtained numbers representing the constant relation of bodies
to each other, he failed to see that they would be reciprocal.
This failure at once removes him from the great discoverers,
and places him among those honourable and valuable labourers
in science whose names are read with respect by students,
but who cannot be recognised by mankind generally, because
the capacities of our minds are too small to retain more than
the lives of a few of the most eminent.

The doctrine of reciprocal proportion must be taken from
him, and he can now no longer hold a place in the history
of the atomic theory other than as the author of an intelligent
attempt which has entirely failed.

I feel sorry to leave him in this state, and a few kind words
will do little good. I believe he would have preferred the
truth; the honour he received was not required by him; the
discovery was not claimed by him; he died in 1793, before it
was known to be worth making. In his works he appears
an honest, earnest man.

HISTORY OP THE ATOMIC THEORY. 1 67

CHAPTER VIII.

DR. BRYAN HIGGINS AND WILLIAM HIGGINS.

Dr. Bryan Higgins was the earliest chemist who seems to
have dealt with the elements of matter, in a chemical, as well
as physical sense, with an attempt to obtain information as to
the primary elements and their atomic constitution, although
he gives no certain results. I find at the laboratory of Owcds
College, among the books forming part of the library of the
late Dr. William Henry, a little pamphlet, proposing a course
of lectures, to be commenced on the 13th November, 1775.

The proposals are said to have been formerly published ; it
is not said how long before. I shall give considerable extracts.

Page 1. " Doctor Higgins, of Greek-street, Soho, en-
couraged by the literary noblemen, and gentlemen who have
subscribed to his courses of philosophic and practical chemistry,
addresses the following proposals to the patrons of natural
philosophy and useful arts.

" That fifty philosophic and literary gentlemen do concur
in promoting experimental inquiries into the elements of
matter and laws of nature, and such other subjects as are
most important in natural philosophy, chemistry, and arts.

Page 3. '* That in these discourses he shall introduce the
natural phenomena, the illustrative observations and experi-
ments of philosophers, chemists, and artists ; and particularly
his notions and experiments concerning the primary elements
and the properties of matter.

Page 9. ** Introductory discourse on matter in general,
called gross matter; on the varieties and distinctions of gross
matter; on the primary elements of matter.

168 MEMOIR OF DR. DALTON, AND

'* Observations on the experiments and philosophy exhibited
in the foregoing course of chemistry, and other experiments
which demonstrate the existence of seven primary distinct
elements of matter, viz. ;

Earth, Air,

Water, Phlogiston,

Alkali, Light.

Acid,

" Experiments, observations, and arguments, persuading
that each primary element consists of atoms homogeneal;
that these atoms are impenetrable, immutable in figure, incon-
vertible, and that, in the ordinary course of nature, they are
not annihilated, nor newly created.

" Observations and experiments, persuading that the atoms
of each element are globular, or nearly so, and that the spiral,
spicular and other figures ascribed to these atoms, are fictions
unnecessary, and are inconsistent with the uniformity and
simplicity of nature, and repugnant to experience. » * *

" Experiments and observations showing that the possible
and known unions of the foregoing elements, and that the
possible and known proportions in which the unions of the
foregoing elements may take place, are more numerous than
the bodies distinguished by philosophers and naturalists ; per-
suading that all known bodies are really composed of one or
more of the foregoing elements; and that all bodies must be
admitted to consist of these only until other elementary matter
is found necessary for the explication of the natural phenomena,
and is demonstrated to exist.

" A classical arrangement on the table of bodies composed
of two or three primary elements, which bodies, in various
chemical processes, not being decomposed, we call chemical
elements, or the elements of the chemists.

" A like classical arrangement of bodies composed of two
chemical elements.

HISTORY OF THE ATOMIC THEORY. 169

" A like classical arrangement of bodies and natural sub-
stances composed of many chemical elements.

OPINION,

"1. That the homogeneal atoms of five elements repel
reciprocally.

" 2. That the homogeneal atoms of two elements attract
reciprocally.

"3. That the dissimilar atoms of five elements attract
reciprocally.

"4. That the dissimilar atoms of two elements repel reci-
procally.

" That the attraction subsisting between elementary atoms
is more forcible in one direction or axis of each atom than in
any other direction, and that there is a polarity in all matter
whatever.

"6. That there is but one species of attraction operating
with great force between the similar or dissimilar atoms of
certain elements, and with less force between those of other
elements, in gradations ; but in all affected by distance and
polarity.

" 7. That the attraction of bodies enumerated as distinct
properties of matter or laws of nature, are nothing more than
the sums of the attraction of their elementary atoms, or these
forces concentrated in a certain degree by the pressure of
repellent atoms, or these forces exerted to the greatest advan-
tage in bodies whose primary elementary attractions are
strongest, and whose primary elementary atoms are also
arranged in polar order.

"8. That specific gravity is not as the quantity of
matter in a given space, but as the quality of the matter, or
the sum of its elementary attractions ; consequently, that light
bodies are not necessarily more porous than the heaviest.**

Page 14. " Observations and experiments, showing the
grounds on which we ought for a while to admit the following
distinctions of earths, viz :
z

1 70 MEMOIR OF DR. DALTON, AND

" Seven earths, capable of forming ductile metals.

" Seven earths, capable of forming metals not ductile.

" Seven earths, incapable of forming metal.

Question 1. Is there but one earthy element, which, in
various modes of aggregation, or in indissoluble combination
with other elementary matter, forms twenty-one earthy bodies?
or. Question 2, Are there three times seven, or seven times
seven earthy elements?

Page 15. " Experimental and geometrical estimation of the
force of this attraction in fortuitous arrangement of the atoms,
and of the force of this attraction in the polar arrangement of
the atoms.

On attraction he says, page 23, " That no element doth
saturate, nor can saturate, the like element ; that no element,
whose atoms attract each other, can saturate any other element
whose atoms attract each other ; that a repellent element doth
saturate non-repellent elements, and vice versa ; that repellent
elements do saturate reciprocally; and that attraction and
repulsion, operating adversely, are the cause of saturation;
and saturation is not a distinct or primary law of nature, but
an effect."

We find here no ideas given of definite compounds, except
so far as the ordinary idea of saturation is concerned. Had
Dr. Higgins any theory resembling the present atomic theory,
he would certainly not have expressed himself so darkly on
the subject of saturation.

We even find that he is not quite freed from the prima
materia^ although he restricts it to the matter of certain
classes, such as the matter of earth forming many earths, the
acid matter forming many acids. He is, therefore, to be
viewed as one bordering on the transmutation theory, not
freed from mystic ideas, but grappling with the subject so
energetically, that in some directions he almost sees his way
into another region of theory.

I shall quote the most important sentences in the *'Experi-

HISTORY OF THE ATOMIC THEORY. 1 ^ \

ments and observations"* of Dr. Higgins. In distilling
acetate of lead, he found a certain amount of what he calls
acid matter in the fixable air, which he considers, as before
mentioned, to be a peculiar principle. It combines with the
empyreal air (oxygen) of the litharge. Not accounting for
the whole amount by the measurements he made, he inferred
" that when the acid matter of acetous acid is employed in
excessive quantity to form fixable air with the empyreal air
of litharge, the fixable air may consist of a little more than
one part of the acid matter, combined with two of the empyreal
air. By a more accurate estimate of the fixable air taken at
85 grains, it is most probable that the proportions would be
found ft be accurately two to one, provided fixable air, like
other acids, may not subsist with various proportions of the
empyreal air." t

He mentions the definite proportion, two to one, because
he obtains the figures approximatively so, but he not only
fails to elevate it into a principle, but speaks of various pro-
portions as probable in the case in hand, and as usual in other
cases. This seems equal to saying distinctly that he recognised
no such principle. But does the term ** various proportions"
allude to fixed numbers, such as two or three ? There is no
reason to suppose this, he uses the word in the ordinary sense
it was then used, no other sense had been given to it, and
any other sense in this place is impossible.

When firing with oxygen the inflammable gases from
acetate of lime, he says, in reference to some experiments
unnecessary to be detailed, *' by other experiments and the
same kind of estimation, the empyreal air appeared to con-
stitute more than two-thirds of the fixable air, and in some it
seemed to be accurately two-thirds ; but after all I continued

* Experiments and observations relating to acetous acid, fixable air, dense
inflammable air, oils and fuel. The matter of fire and light, metallic reduction,
combustion, fermentation, putrefaction, respiration, and other subjects of
chemical philotophy. By Bryan Higgins, M.D. London, 1786.

t Pago 23-2.

1 72 MEMOIR OF DR. DALTON, AND

to suspect that the proportions of the principles are not the
same in every specimen ot the elastic fluid which we consider
as fixable air. When the dense inflammable air first expelled
from charcoal was used, the result was nearly the same. And
from the whole, I conclude, that when as much inflammable
air of this kind is employed, as can be converted in the
explosion, by the empyreal air, the fixable air consists of one
part by weight of the acid matter of acetous acid or charcoal,
and nearly, or accurately, two pSrts of empyreal air; and
almost one-fifth of this kind of inflammable air is phlogiston,
and the remainder mere acid basis of fixable air, and of acetous
acid, charcoal, oils, spirits, and of all substances that yield
acetous acid or dense inflammable air abundantly."* ♦

The same remarks apply to this. The " nearly" two parts
are just as probable, in his mind, as the "accurately" two
parts, which would not have been the case had he found any
defining law to express on the subject.

Then he says, further on,t " It seems, therefore, that the
proportions in which the acid and phlogistic matter are com-
bined, in different specimens of inflammable air expelled from
vegetable substances, do vary considerably," &c. This refers
to his tables of results.

He believes that the particles of the different gases unite to
form molecules of compound gases, page 317: "I consider
the specific gravity as a safe guide in our investigation of
these affinities and of their order, in regard only to the elastic
fluids which seem to consist of no more than one kind of
gravitating matter engaged in the repellent atmospheres ; and
of fixed air, dense inflammable air, acid air, the phlogistic
alkaline air, and others, I would observe, that the atmospheres
include molecules, instead of solitary ultimate parts; for,
without this chemical union of heterogeneal parts, and the
formation of molecules, an elastic fluid of the kind that I now
speak of could not differ, as it does, from either kind of matter

•Page 291. j Page 394.

HISTORY OF THE ATOMIC THEORY. 1 73

of which it is composed. From this consideration of the
attractive forces which tend to form molecules, and of the
atmospheres which, in compound elastic fluids, encompass the
molecules, but not the ultimate parts severally, we derive an
easy explanation of the phenomenon so often noted in the
preceding pages — I mean, the conversion of a substance, not
into air, but into two or three diflferent elastic fluids, by mere
ignition,"

Dr. Higgins thinks of atoms, of simple particles, and even
speaks of gases uniting, in some cases, in nearly, if not accu-
rately, a fixed proportion, and yet he sees no law. He does
not carry his idea far enough. If the molecules are formed by
the union of two particles the proportions must of necessity
be fixed, or if any number of particles unite, the proportions
are fixed, unless the molecules are to be supposed of different
constitutions. In this last case, they would constitute a
mixture of different gases. But it was not known at this
period that all bodies had a fixed constitution, otherwise one
would have supposed that Dalton's laws would have been
readily arrived at by Dr. Higgins. On the other hand, his
theory was not clear, or he would have been led by it to
decide on the necessity of fixed constitution as a result,
But we obtain no results affecting chemical philosophy.
And yet amongst other questions which he says " we shall
find no difficulty in answering," is, " Why does any excessive
quantity of empyreal or of inflammable air, beyond the deter-
minate proportions in which their gross parts can combine,
remain elastic and unaltered, or not altered in any considerable
part of it, after the combustion ?" *

The nearest answer he gives as to the proportions is
the following : — " The matter of fire limits the quantity in
which aeriform fluids, and bodies containing it, can combine
chemically." t We may conclude then that nothing in the
gases themselves determined the proportion, but the cause
was in " distinct atmosphere of fiery matter."
• Page 830. f P«»g« 307.

1 74 MEMOIR OF DR. DALTON, AND

In reading the first part of this question we suppose he
must live as a discoverer ; in reading the second part, we find
him timidly committing suicide. He wavers between his
theory and his experiments. If determinate proportion be a
law, he might have supposed it rigid, like other laws of
nature ; but he leaves a portion of the residue altered, so
that, after all, we only receive from him indeterminate, or
nearly determinate proportions.

The experiment to which the question refers occurs in
p. 296. He draws no valuable conclusion from it. He says
also, p. 299, " In the combustion of charcoal with empyreal
air, the expenditure of the latter, in fixable air and water,
was always found to be more than thrice the weight of the
charcoal. I could now easily ascertain the proportion of
these, and even the quantity of the acid and phlogistic matter
in this and other bodies; but as my present purposes are
answered by approximation, I think it unnecessary to detain
the reader any longer on this subject."

His principal object was to explain the nature of fire, which
he considers as subject to the laws of gravitation, and to be
the cause of the aeriform state of bodies.

The only law in which be introduces numbers is the fourth
of his " primary notions of the matter of fire." " The
changes of repellent matter, by which attractive and gravi-
tating particles form elastic fluids, are distinct atmospheres of
fiery matter, in which the densities are reciprocally as the
distances from the central particles, in a duplicate or higher
ratio." *

His writings are mostly in the first stage of thought before
opinion is formed. Commentators on such persons are obliged
to extend the ideas a little in order to make them clear, and
so the original writer gets credit for more than he had ever
done. Such writers are of great value when they lead towards
discoveries ; but we are apt to give them the entire honour when

• Page 306.

HI8T0EY OF THE ATOMIC THEORY. 175

they deserve only a part. As far as our subject is concerned
Dr. Higgins has small claims. His opinions on atoms might
have been held by the ancients: whilst standing on their
shoulders, it would have required much less sagacity to
discover than was needed for them. He speaks of the sums
of the forces of atoms measuring the attraction of matter, but
does not suppose that if matter be atomic, the number of
atoms might also, in this way, be got comparatively.

We might say, however, that Di|^ Higgins began the study
of atomic chemistry, properly so called, although he made
little advance in it.

The next person worthy of note is of the same name and
family. The following extracts contain what is of greatest
importance in connection with our subject. The title page of
the volume quoted from is, "A Comparative View of the
Phlogistic and Antiphlogistic Theories, with Inductions, &c.,
by William Higgins, of Pembroke College, Oxford. The
Second Edition.

" Est quoddam prodire tenus, si non datur ultra.

" London : Printed for J. Murray, No. 32, Fleet Street.
1791." The first edition was in 1789.

Page 14. " It is generally allowed, and justly, that nitrous
air consists of dephlogisticated air and phlogistic, in the pro-
portion of two of the former to one of the latter. The
supposition of its containing phlogiston, I Bope, will hereafter
appear to be erroneous ; therefore, every ultimate particle of
phlogisticated air must be united to two of dephlogisticated
air; and these molicules, combined with fire, constitute nitrous
air. Now, if every (one) of these molicules were surrounded
with an atmosphere of fire equal in size only to those of
dephlogisticated air, 100 cubic inches of nitrous air should
weigh 98,535 grains; whereas, according to Kirwan, they
weigh but 37 grains. Hence, we may justly conclude that
the gravitating particles of nitrous air are thrice the distance
from each other that the ultimate particles of dephlogisticated

1 76 MEMOIR OF DR. DALTON, AND

are in the same temperature, and, of course, their atmospheres
of fire must be in size proportionable ; or else some other
repelling fluid must interpose. The size of the repelling
atmospheres of nitrous air thus considered, and likewise the
weaker attraction of the molicules of this air to dephlogis-
ticated air than that of the ultimate particles of phlogistic in
their simple state, it is surprising to me, with how much more
facility the former unites to dephlogisticated air than the
latter." %

After speaking of the combustion of sulphur, he says, p. 35,
" A good many more facts might be urged on this subject ;
but, in my opinion, enough has been adduced to convince an
impartial reader that all the phenomema above recited are only
explicable by entirely leaving out phlogiston, and supposing
sulphur to be a simple subtance, whose ultimate particles
attract dephlogisticated air with forces inherent in themselves,
independent of phlogiston or concrete inflammable air, as an
alkali does an acid, or gold and tin mercury ; and likewise sup-
posing the combustion of sulphur to be as simple a process as
that of light inflammable air; that is, that there is no dephlo-
gistication, or formation of water, during the union of the
oxygenous principle to sulphur, as containing not a particle
of light inflammable air in its constitution. I have often
combined sulphur rendered perfectly dry, and dephlogisticated
air likewise, deprived of its water by fused marine selenite in
large proportion over mercury, and could never observe that
water was produced. Indeed it may be said that the volatile
sulphurous acid, which is always the result of this process,
may redissolve it ; but this is not very likely, when a small
portion of water will deprive it of its elasticity."

" According to Mr. Kirwan, 100 grains of sulphur require
143 grains of dephlogisticated air to convert them into
volatile vitriolic acid ; but they require much more in order
to become perfect vitriolic acid. Highly concentrated vitriolic
acid contains two parts of dephlogisticated air, and one of

HISTORY OF THE ATOMIC THEORY. 1 ^^

sulphur, exclusive of water. One hundred and forty-three
grains of dephlogisticated air contain 41 of water, for lime
will abstract 26 grains from it, and the remainder cannot be
separated from it in its aerial state; therefore 100 grains
of sulphur, making an allowance for water, require 100 or
102 of the real gravitating matter of dephlogisticated air
to form volatile vitriolic acid ; and as volatile vitriolic acid
is very little short of double the specific gravity of
dephlogisticated air, we may conclude that the ultimate
particles of sulphur and dephlogisticated air contain equal
quantities of solid matter ; for dephlogisticated air suffers
no considerable contraction by uniting to sulphur in the
proportion merely necessary for the formation of volatile
vitriolic acid. Hence we may conclude, that, in volatile
vitriolic acid, a single ultimate particle of sulphur is inti-
mately united only to a single particle of dephlogisticated
air ; and that, in perfect vitriolic acid, every single particle of
sulphur is united to two of dephlogisticated air, being the
quantity necessary to saturation."

** As two cubic inches of light inflammable air require but
one of dephlogisticated air to condense them, we must suppose
that they contain equal number of divisions, and that the
difference of their specific gravity depends chiefly on the size
of their ultimate particles; or we must suppose that the
ultimate particles of light inflammable air require two or
three, or more, of dephlogisticated air to saturate them.
If this latter were the case, toe might produce water in an
intermediate state, as well as the vitriolic or the nitrous
acid, which appears to be impossible ; for in whatever pro-
portion we mix our airs, or under whatsoever circumstance
we combine them, the result is invariably the same. This
likewise may be observed with respect to the decomposition
of matter. Hence we may justly conclude, that water is
composed of molicules formed by the union of a single ulti-
mate particle of dephlogisticated air to an ultimate particle of

2A

178 MEMOIR OF DR. DALTON, AND

light inflammable air, and that they are incapable of uniting
to a third particle of either of their constituent principles.
The above notions of water and vitriolic acid being strictly
kept in view, let us now proceed to inquire into the nature of
sulphur and vitriolic acid, and their various effects on different
bodies in the antiphlogistic doctrine. It has been already
observed that metals attract dephlogisticated air with greater
force than sulphur, and that sulphur attracts it with greater
force than light inflammable air. It has likewise been
observed, that vitriolic acid and water, mixed in a certain
proportion, will calcine metals with greater facility than
concentrated vitriolic acid, and that water will have very
little effect on metals in a common temperature. These facts,
though they may appear contradictory in themselves when
slightly considered, may be accounted for on the following
principles, and are, in my opinion, inexplicable by any other
means whatever."

"Let us suppose iron or zinc to attract dephlogisticated air
with the force of 7, sulphur to attract it with the force of
6 7-8 ths, and light inflammable air with the force of 6 5-9 ths.
Let us again suppose these to be the utmost forces that can
subsist between particle and particle. That is to say, in
water dephlogisticated air is retained with the above force,
and likewise in volatile vitriolic acid, with the force already
mentioned. It is unnecessary to introduce here the aggregate
attraction which frequently preserves a neutrality between
bodies, as, for instance, between water and zinc, or water
and iron. Stating the attractive forces in the above propor-
tion, which I am led to believe is just from facts already
observed, we should imagine that iron or zinc would calcine
in water with greater facility than in vitriolic acid ; and if
some other circumstances did not interfere, it must be the
case. This the following will in some degree illustrate.

Let S be a particle of sulphur, d a particle of dephlogisti-
cated air, which it attracts with the force of 6 7-8 ths, and let
the compound be volatile sulphureous acid; here the tie be-

HI8T0BY OF THE ATOMIC THEORY.

179

tween S and d is greater by 2-8 ths, than that between the
constituent principles of water, which is but 6 5-8th8.
As the attraction of bodies
is mutual, let us suppose S
to possess one-half of this
force, which is 3 7-l6ths,
and this to be its utmost
exertion, and likewise d to possess the other half, which
is 3 7-l6ths more, which will unite them with the above-
mentioned force. Let us suppose another particle of dephlo-
gisticjited air D to have a tendency to unite to S, with
the force of 3 7- 16 ths, in order to form perfect vitriolic
acid ; to receive D, S must relax its attraction for d one-
half. That is, the force of 3 7-l6ths will be divided and
directed in two diflferent points, which will reduce the attach-
ment of dephlogibticated air and sulphur in perfect vitriolic
acid to 5 l-18th."

Page 66. " When vitriolic acid, whether diluted or not, is
mixed with oil, an ultimate particle of vitriolic acid influences
with a certain force an ultimate particle of oil, while the
latter attracts the vitriolic ^

acid with the same force.
The oil will not take D d
from S ; but from the joint

attraction of S D d

to oil, they will approach
with equal pace, and combine. Thus this mixture more than
mechanically, but not quite chemically united, may be resolved
into the different fluids mentioned above. The particle of oil
will retain D or rf, and form fixable air ; at the same time
that S will retain rf or D with its full force, and form volatile
vitriolic acid."

Page 132. ** In my opinion the purest nitrous acid contains
5 of dephlogisticated to I of phlogisticated air. Nitrous air,
according to Kirwan, contains 2 of dephlogisticated 4o 1 of

180

MEMOIR OF BR. D ALTON, AND

l)lilogisticated air. According to Lavoisier, ICO grains of
nitrous air contain 32 grains of phlogisticated air, and G8 of
of dephlogisticated air. I am myself of the former philoso-
pher's opinion ; I likewise am of opinion, that every primary
particle of phlogisticated air is united to two of dephlogisticated
air, and that these molecules are surrounded with one common
atmosphere of fire."

" To render this more explicable, let us suppose P to be an
ultimate particle of phlogisticated air, which attracts dephlo-
gisticated air with the force of 3 ; let a be a particle of
dephlogisticated air, whose attraction to P we will suppose
to be 3 more, by which they unite with the force of 6. The
nature of this compound will be hereafter explained.

" Let us consider this to be 3

the utmost force that can ^-^^

subsist between dephlogisti-
cated and phlogisticated air.
Let us suppose another par-
tide of dephlogisticated air b to unite to P, they will not
unite with the force of 6, but with the force of 4^ ; that is
the whole power of P, which is but 3, will be equally divided
and directed in two points
towards a and b ; so that P
and a b will unite with the
forces annexed to them ; for
the attraction of a and 6 to P

meeting with no interruption, will suffer no diminution.
I consider to be the true state of
nitrous air. Let us now suppose
another particle of dephlogisticated
air c to unite to P, it will combine
only with the force of 4, whereby
a, b, c and P will gravitate toward
one another. Such is the state of
the red nitrous vapour or the red
nitrous acid.

HISTORY OF THE ATOMIC THEORY.

181

This is the most

" Let us again suppose a fourth

particle of dephlogisticated air d

to combine with P, it will unite

only with the force of 3}. This,

I think, is the state of the pale

or straw coloured nitrous acid.
"Lastly, let us suppose a fifth

particle of dephlogisticated air g,

to unite to P, it will combine with

the force of 3 3-5 ths, so that a, h,

c, d and e will each gravitate to-
wards P as their common centre of gravity.

perfect state of colourless nitrous

acid ; and in my opinion no more

dephlogisticated air can unite to

the phlogisticated air, as hav-
ing its whole force of attraction

expended on the particles of de-
phlogisticated air, a, 6, c, c/, e.
This illustrates the nature of
saturation. Thence we find that
dephlogisticated air is retained
with less force in the perfect or
colourless nitrous acid, than in
the straw-coloured, or in the red,
or in nitrous air."

Page 194. " If the calcination of metals depended solely
upon their union to dephlogisticated air, it must be supplied
by water, when steam is brought in contact with them ; and
as every particle of light inflammable air is united but to a
single particle of dephlogisticated air, inflammable air must
be disengaged in proportion to the quantity of dephlogisti-
cated air which unites to the metals ; or, in other words,
according to the degree of calcination it acquires."

182 MEMOIR OF DR. DALTON, AND

Higgins wrote on phlogiston, his chief object being con-
nected with it. In an octavo volume of above 300 pages
these are nearly all the extracts relating to this subject. We
find, then, that he did not establish a law in connection with
these ideas. We must conclude, then, that he did not see
their importance, that he did not see their application. Not
only so, but being lost amongst so much material, we do not
find that they were so written as to draw any attention, nor
does he seem to have wished to do so. He wished to draw
attention to what was in reality of less importance, his objec-
tions to phlogiston. The magic sword that would have slain
all his enemies he threw away as some common truncheon.
The magic lamp that would have given brilliance to him and
to science, was found, after some years, rotting in his cellar.
As regards the effect his book had on his cotemporaries. Dr.
Thomson, of Glasgow, is the best authority. We see from
him that no idea of an atomic theory was got from Higgins.
His opinions were given and received as a speculation more
than as expressing a fact or a law.

He says in his Annals of Philosophy, May, 1814, Vol. III.,
p. 331, "I have certainly afl&rmed that the atomic theory
was not established in Mr. Higgins's book. And here is my
reason. I have had that book in my possession since the year
1798, and had perused it carefully; yet I did not find any-
thing in it which had suggested to me the atomic theory.
That a small hint would have been sufficient T think pretty
clear from this, that I was forcibly struck with Mr. Dal ton's
statements in 1804, though it did not fill half an octavo page;
so much so, indeed, that I afterwards published an account of
it ; and I still consider myself as the first person who gave
the world an outline of the Daltonian theory."

This is put too strongly. Had Dr. Thomson paid as
much attention to Higgins's book as to the remarks of
Dalton, he would certainly have made a great advance on

HISTORY OF THE ATOMIC THEORY. 183

the chemists of the period, by understanding definite pro-
portion, and learning to reason in the spirit of the atomic
theory.

William Higgins made an advance on Bryan Higgins in this
theory of sulphur and heat, and he was a man evidently of an
acute mind. But he was destined to find Emerson's saying true,
that we often find in the sayings of great men our own rejected
ideas. He was heir to the common opinion that atoms existed,
and the opinion of Dr. Higgins that they united and formed
molecules of compound bodies. He applied the reasoning
further, and said that they must then unite in numbers of one
or two, or three, and that there could be no intermediate
combination, as there were no intermediate division of
atoms. He applied this reason in two or three cases. These
cases, such as nitric acid, are so clear and beautiful, that
we can only be surprised that the general law was not
seized on. They are the first clear and satisfactory reasons
given for saturation, and for definite proportion in general.
Higgins was therefore the first man who used the idea of
atoms with such force as to be serviceable in chemistry. He
used the idea of ultimate particles and the molecular state of
bodies to illustrate saturation, and definite and multiple pro-
portion, and gave us therefore the fundamental ideas of
stoechiometry as they exists in chemical science, from which
everything else might have easily flowed.

He had seen the right road, but dared not go farther.
But we must take his own apology, ** Est quoddam prodire
tenus, si non datur ultra." It is something to have gone thus
far, if he had no power to go beyond it.

Like Dr. Higgins, and the most of the chemists of last
century, he assumed certain forces of attraction, and endea-
voured to give comparative values to the forces of combination.
These numbers representing affinity misled Higgins. Had he
seen any general law, he would have seen that weights repre-

1 84 MEMOIR OF DR. DALTON, AND

sented the comparative number of his atoms, but this he did not
see with any distinctness, or he would have used Kirwan's
numbers, which he knew well enough, and would have found in
them atomic weights. But atomic weights were never thought
of at all. It was not even certain then that all matters
gravitated, although he held the present opinions on it. He
reasoned to a certain extent in the true spirit of the atomic
theory, but becoming entirely involved in dynamics, he entirely
missed his way. Dynamics have hitherto entirely failed in
chemistry. Their power has been used in upsetting their
friends, and Higgins fell a victim to their forces.

Having for a moment laid hold of the idea that bodies
which are atomically constituted must be formed of the union
of one or more bodies, and of no intermediate atoms, he drew
insufficient conclusions, and all its prospective advantages
were lost to him. The want of suitable results, which it was
his fault for not finding, seems to have caused him to let go his
magic weapon, or to view his own opinion as a speculation.
In his mind they exist as very little more.

I look upon him as the first man who ever in his imagina-
tion formed a correct atomic compound, and gave a correct
analysis, in spite of the thousands of previous speculations
and the simplicity of the idea, but one who lost the oppor-
tunity of elevating his idea into a great law of nature. It is
well to express the claim of a discoverer in the widest and
in the fewest words. He expressed the fact of atomic simple
and multiple proportion, which is the foundation for all the
other atomic laws, although in his mind it was not raised to
the dignity of a great law, and it is for great laws only that
we can give great honours in this case.

Higgins speaks so clearly and simply that we can readily
believe that he would have illustrated the laws of chemical
combination with great beauty had he seen the great value of
his ideas. There is no obscurity in his language ; there is no

HISTORY OF THK ATOMIC THEORY. 185

difficulty in telling exactly his place in science ; but there is a
difficulty in defining it exactly when we have to deal with
Dalton, who grasped the whole so much more firmly, enlarged
it, placed it, and established it in a series of laws. Any one
to be put before Higgins must have made great advances :
he cannot be put down by any obscure sentences dragged from
any author. Any one to eclipse him must be fuller, more
decisive, and more systematic.

From the want of these qualities Higgins appears more in
the character of a great thinker than of a great discoverer.

2B

186 MEMOIE OF DR. DALTON, AND

CHAPTER IX.

RICHTER.

During the disputes as to Dalton's priority of discovery, it
was frequently asserted that his atomic laws were not new,
and they were, as is usual in such cases, attributed to various
persons. Of these persons, Higgins, in this country, and
Richter, in Germany, have been the most prominent. I have
endeavoured to show exactly the position of Higgins ; I shall
do the same with Richter. Higgins came first with clearness
and simplicity, uttering a beautiful idea which he failed to
follow up ; Richter came close after him, with great labour
and enthusiasm, filled with a great idea of the study in which
he was engaged, and obtained a law which he failed to follow
up ; he lost himself in complicated theories, having no idea
how simple w^as the truth he sought for. Both were
neglected, as happens when men fail to give completeness
to their inquiries, even in the eyes of those who study
and are willing to learn.

Richter's books are — *' Anfangsgriinde der Stoechyometrie
oder Messkunst Chymischer Elemente." 3 vols. Bresslau
und Hirschberg, 1792-4 ; and " Ueber die Neuern Gegen-
stande der Chymie," 1791-1802.

I shall give rather copious extracts from his works, shewing
the direction of his inquiries, and the ends he attained.

Richter, Vol. I., Preface.

" Mathematics includes all those sciences which refer to
magnitude, and consequently a science lies more or less in the
province of mathematics (geometry), according as it requires
the determination of magnitudes. In chemical experiments

HISTORY OF THE ATOMIC THEOKT. 187

this truth has often led me to the question, whether and how
far chemistry is a part of applied mathematics ; and especially
in considering the well-known fact, that two neutral salts, when
they decompose each other, form again neutral compounds.
The immediate consequence, in my opinion, could only be,
that there are definite relations between the magnitude of
the component parts of neutral salts. From that time I con-
sidered how these proportions could be made out, partly by
exact chemical experiments, partly combining chemical with
mathematical analysis. In my inaugural dissertation, pub-
lished at Konigsberg, in 1 789, I made a slight attempt, but
was not then supplied with the requisite chemical apparatus,
nor was I sufficiently ready with all requisite information,
bearing on my present system, imperfect as it may be. The
result, therefore, was very imperfect. 1 promised, however,
not to let the matter rest with that imperfect essay, but to
work out this branch with all the accuracy and profundity of
which I was capable, as soon as I was supplied with the
requisite conveniences. This promise, I hope in the present
volume, to make good, although I am far from believing that
what I am now going to say will not be in need of still more
thorough and accurate elaboration, for who will venture to
limit the extent and the power which is the destination of a
young and budding science."

He was the first to speak of a science of stoechiometry,
and began formally to lay the foundation. We may even
say that he commenced the systematic study for which he
gave us also the most appropriate word. I cannot say that
he began the science, and it will be seen that his mode of
inauiry was wanting in directness and his results in com-
pleteness.

In page 29 of the preface, he says, " as the mathematical
pordon of chemistry deals in a great measure with bodies
which are either elements or substances incapable of being
decomposed and as it teaches also their relative magnitudes,

1 88 MEMOIR OF DK. DALTON, AND

I have been able to find no more fitting name for this scien-
tific discipline than the word stcechiometry, from aroix'^tov
which, in the Greek language, means a something which
cannot be divided, and fierQuv which means to find out relative
magnitudes."

Here, then, is a man prepared for the work, one who reso-
lutely laboured for many years to find the law by which the
elements combine, by " number, weight, and measure."

We have seen already that many facts were known, and
that even reciprocal proportion was almost attained in the
diagrams which have been given, and that the most far-
sighted chemists saw the natural necessity for a constant
proportion in combinations; but when the well-known laws
agreed upon by chemists were put together, we see how few
G. Morveau's list amounted to.

Richter did a great deal of work, especially in connection
with the chemistry of the metals, but everything was held
secondary to his great idea of definite proportionate quantities
(bestimmte Grossen verbal tnisse). On the title pages of the
various papers or parts of volumes, written after his stcechio-
metry, he has preserved as a motto " Uavra (OEOS) fjiBTpw
Ktti api^jiiu) Kai ara^fiw ^i^ra^i' (ac). This, from the ' Wisdom
of Solomon,' chapter xi., v. 20, is exceedingly appropriate, but
the context evidently shows that it was not applied to any
such subject ; at the same time it is introduced as a proverb
would be, or a well-known universal law coming in aptly to
illustrate one particular point to which it bears no more inti-
mate relation than to innumerable others. It must, however,
be confessed, that this expression is given with a minuteness
and fulness which warrants the conclusion that it was not
uttered until after many and profound speculations on the
order of creation. The sentence is the expression of the cir-
cumstances in all their fulness, but like many other sentences
of antiquity, the meaning is not clear till the facts have been
discovered piece by piece.

HISTORY OF THE ATOMIC THEORY. 189

The most important sentences bearing on the subject of
Richter's volumes have been selected, including everything
which seems to indicate any knowledge of the subject. His
prolixity is excessive, every little idea is long dwelt upon,
and as an example of the small fear he had of too much
enlarging his book, it may be stated that he actually writes
a system of algebra in one of the volumes, because a little
algebra is wanted for the full understanding of his demon-
strations. It may be that there are sentences hidden among
other portions of the book less directly bearing on his subject
which would indicate great knowledge, for although I have
spent many days among his six volumes, I have certainly
omitted some parts which seemed to me out of the range of
stoechiometry. But his doctrines are not to be got in frag-
mentary sentences, so that the loss of any such sentences
cannot, in the least, affect the result.

Richter's St(echiometry, Vol. I., Page 121.

Definition 1.

** Stoechiometry (stoechyometria) is the science of measuring
the quantitative proportions, or the proportions of the masses
in which chemical elements stand in regard to each other.
The mere knowledge of these relations might be called
* quantitative stoechiology.'

Principle 1. P. 123.

" Every infinitely small particle of the mass of an element
has an infinitely small part of the chemical attractive force or
aflBnity.

Experience 5.

" In order to make a neutral compound out of two elements,
it is needful, as each of the elements is of the same constitu-
tion at one time as at another, to take the same quantity for
the first part formed as for the second part. For example, if

190 MEMOIR OF DR. DALTON, AND

two parts of lime require five parts of muriatic acid for solu-
tion, six parts of lime will require fifteen of the same acid.

Experience 6. P. IM.

" When two neutral solutions are mixed, and a decomposi-
tion follows, the new resulting products are almost without
exception neutral also, but if the solutions of one or both are
not neutral before mixing, the products after mixture are also
not neutral.

Corollary 1.

" The elements must therefore have amongst themselves a
certain fixed proportion of mass. To determine which, their
neutral compounds generally give the best opportunity.*

Corollary 2.

" If the weights of the masses of two neutral compounds
which decompose each other are A and B, and the mass of
the one element in A is a, and that of the one in B is b, then
the masses of the elements in A are A — a, a and those in B
are B — J, h. The proportions of the masses of the elements
in the neutral compounds before decomposition are A — a : a
and B — h : h ; but after decomposition the new products are
fl5_j_B — J, and 6+ A — a, and the proportion of the masses of
the elements is a : B — 6, h : A — a. If the proportion of the
masses in the compounds A and B is known, that in the new
products is known also.

* In German " Der Stoff ihrer neutralerVerbindungen ofterseinen Bestimm-
ungsgrund abgeben kann." StofF is explained thus : Einleiting : Erklarung
14. " Das materielle oder korperliche Subjekt, worinnen sich die chymische
Verwandtschaft befindet, nenne ich die Masse, Prinzip oder Stoff (Massa) des
Elementes. Die Summa der Massen der Elemente, so eine neutrale auflosung
bilden, ist die Masse oder Stoff (Massa) der neutralen Auflosung."

That is, "I call the material or corporal suhjectum in which the chemical
affinity resides, the Mass, Principle or StuiF (Massa)."

In a note, he says, — " There is present in the Element a certain suhjectum
to which the chemical attractive power or the affinity is bound, this is the Mass
of the Element."

HISTOBY OF THE ATOMIC THEORY. 19 1

If a+B— Z>=C and HA— a=D then a=C-f6— B=6-|-A
— D and C— B=A— D, so also D— B=A— C. In addition
6=a-fB—C=D— A-fa.

Theorem 1. P. 125.
" The chemically attracting power by which one element
a enters into neutrality with another A — a presupposes an
opposite action of the same kind in the latter, and these
two powers are equal to each other.

Theorem 2. P. 128.
" If a neutral compound A whose elementary masses A — a
and a are removed from combination by a definite quantity of
a third element J, and the whole mass of one element a for
example is set free, the force that causes this phenomenon is
equal to the difference between the separating element h and
the separated element a.

Theorem 3. P. 130.

" When two neutral compounds A and B, the masses of
whose ingredients are A — a, a and B — 6, b mutually decom-
pose each other, so that the new products A — a-\-b and
B — 6+ a are formed, the forces that partly cause and partly
hinder this action, are equal to the difference of affinities of
the elements A — a and B — h towards each of the elements
a and 6." Afterwards he said,

" When I finished the pure stoechiometry, two years ago, I
did not think it would be needful to make any additions to its
contents. In the first place I thought it had all that practical
stoechiometry required, &c.*

Vol. II., Par. V., P. 4.
Having decided by experiment that 1000 parts carbonate
of lime contain 559 earthy matter, be sums up as follows

• Preface to Vol. I., Part 2. 1794. Later than Vols. IL and IIL

192 MEMOIR OF DE. DALTON, AND

his experiment with 5760 grs. of muriatic acid and 2393 grs.
of chalk.

" If now we desire to find the proportion of the elements in
the pure salt forming a neutral body, we must first seek to
determine the amount of lime out of the weight of the crude
lime used or the aerial salt of lime. This amounts to 2393
grains. According, then, to par. 1, 1000:559 = 2393 : lime,
and the lime is equal to ^^^V^=\S31 ; this, when sub-
tracted from the 2544 grains of the neutral mass obtained,
leaves a residue of 1207 grains, the weight of the muriatic
acid. If, then, 1207:2544*=! 000: 1107, it is clear that in the
salt of lime (chloride of calcium) 1 000 parts of muriatic acid
are united in a neutral state with 1 1 07 parts of lime ; the
proportion of the elements in this neutral solution is then
best designated by 1000: 1107.

In this manner all the earths are treated, after which he
gives the relation of the quantities of alkaline earths towards
sulphuric acid and each other.

Order of the masses of alkaline earths towards muriatic
acid. § XXII. P. 27.

" If we set in a row the numbers which have been found
representing the masses of alkaline earths which unite with
1000 parts of muriatic acid, we obtain the first series of
quantities of the alkaline earths. The muriatic acid is the
determining element (elementum determinans) of this series,
and every member of this series represents an element de-
termined (elementum determinatum). In order to designate
the elements to which we affix these numbers, we shall make
use of the chemical signs for the sake of convenience, setting
the determining element, or rather its sign, at the top, or at
the side of the series of quantities ; and when no number is
placed, we shall suppose it to be 1000. In order to fix these
signs in our memory, we shall here repeat them." (These
signs it is not convenient to use.)

* This evidently ought to have been 1337.

HISTORY OF THE ATOMIC THEORY. 193

** According to the paragraphs quoted, the following is
the series of the alkaline earths in their relation to muriatic
acid : —

MURIATIC

ACID.

ALUMINA.

MA0NB8IA.

LIME.

BARYTA.

784

858

1107

8099

" Little as the niembers of this series appear to follow any
certain order, it is nevertheless decidedly the case; at the
same time the inquiry into the law of these series is one of
the most difficult problems which stcechiometry gives us to
solve, and if we do not go to the inquiry with sufficient prac-
tical and theoretical exactness, we shall not succeed in our
inquiry into these laws or orders (of the numbers). And
now, to inquire into the law of the series before us, let
us first seek the difference between each member and its
successor, and we obtain 858—734=124, 1107—858=249,
3099— 1107=1992. Let us then use the first difference to di-
vide the two following differences, and we obtain ff|=2+TiT,
-W**=16rST. Then let us see if one quotient allows of divi-
sion by the other, that is, let us divide IG+xfr by 2+1-^4. If
we bring divisor and dividend under the same denomination of
124, this will be \6-{-Thi=^iW- and 2-|-^T=flf; therefore
•W6^?aV-=W9«- and 249 is contained exactly 8 times in 1992,
consequently Wi^=S. From this it is clear, that when we
have the first difference 124i=-j^, all the succeeding differ-
ences may be so divided by it that nothing remains; the half
here mentioned is only t-tH-^ in 858 parts=0.0006 and still
less in the other members of the series, it is, therefore, of no
importance; it is impossible in experiments to arrive at
such minuteness, at the same time in calculating the pro-
portion to 1 000 parts, it was necessary to throw away small
unimportant fractions, otherwise it would be needful to use
an enormous number of figures in order to designate the
quantities. Now H^ X 2 = 249; and ^P X8= 1992, con-
sequently 734-h^l^ = 858i, 734+*«^+ = ?^X2=lI07i ; 734

2C

194 MEMOIR OF DR. D ALTON, AND

4.A^+ jLApjj _|.AjjL xjLa=3099i. In order better to understand
all, let us make 734=a, -^^=6, then 734=0!, 858^=a-f 5,
ll07i = a-\-b-^2b = a-{-Sb, 3099^=a+b-{-2b^\eb=a-\-\9b,
From this the quantitative series appears in the following
order : —

MURIATIC ACID.

ALUMINA.. MAGNESIA. LIME. BARYTA.

a a-\-b a+3 6 a+19 6

" Now this series remains always the same, even when we
put a higher or a lower number for the mass of the determining
element, for if the mass of the determining element is n times
greater or n times smaller, then, in the first case, all the
terms w^ould be n time& greater; that is, multiplied by n; and
in the latter case n times smaller or divided by n, and the
order of the differences would remain always the same ;
because what occurs with one of the differences must occur
also with the others, if otherwise the determining element
must still be considered as such. When this series is atten-
tively considered, we observe that the difference of the suc-
cessive terms is a mathematical product of the first difference
b with an odd number. According to it the quantities in which
the hitherto known alkaline earths assert their neutrality with
muriatic acid are terms of a real arithmetical progression, the
terms of which are found, when the product of a certain
quantity with an odd number is added to the first term, only
that between them many odd numbers, such as 5, 7, 9, 11,
13, 17, are left out. This is more remarkable, as the differ-
ences which the first term makes with the succeeding ones
may be represented entirely by odd numbers ; for one need
©nly suppose that the mass of the determining element is
divided by J, then all the terms of the series would be at once
divided by b, and appear in the following form : —

Muriatic Acid JLiIQ^_ — £.qjlq. — ft^ 9

ALUMINA.

MA0NB8IA.

-.i -t V •■ a •«! 4 » -■ -.i i V

LIME. * * « BARYTA

a
I

f+l

T+3 * * * -f+19 . . .

HI8T0KY OF THE ATOMIC THEOKY. 195

<* In this case the first term would be-r* and if it were all
expressed in numbers then would -f- =THf?=-Wir=5-l-fH'
and the mass of the determining element ^^^-^V^i^^^W
=8r4ir. In this way all the members are obtained in numbers,
when 1, 3, and 19 are added to the first term WaS and the
elements observed which are designated by these figures. It is
very probable that the terms -^ +6, -f-+7, -f +9, -f- +11,
_£_-fl3, _«_-|-15, -«_+ 17 are wanting in the series, and the

b b b

reasons for considering this probable, will be shewn in a suit-
able place.

" Preliminary determination of the order of the alkaline
earths which enter into neutrality with vitriolic acid,
§ XXIIL, p.33.

** If we put in order the amount (mass) of alkaline earths
which stand in neutrality with 1000 parts of vitriolic acid,
in the manner adopted with muriatic acid, the following
series of quantities is obtained : —

VITRIOLIC ACID.

MAGNESIA.

LIMB. ALUMINA.

BARYTA.

616

796 1063

2226

" In order to discover the law of this series let us, as in the
former case, subtract the first term from all the succeeding,
and we receive 796—616=180; 1053—616=437, 2226—616
=1610. Let us see now if the first difference can so divide
all the rest, that nothing, or at least very little, remains, then
HJ=2+T^, -VW=8-Mia. As nothing can be discovered
here on account of the variety in the remaining fractions,
let us divide every difference by 90 as the half of the first
difference, and we obtain -W=2, W^=5, -»-|J^=18— f^. The
fractions here are not so considerable as before, although too
large to be thrown away. Until, therefore, we are able to
complete the order let us make 616=616, 796=616—2.90,*
1053=616+5.90— H, 2226=6164-18.90— i^."

• 2.90 means 2 X ^0.

196 MEMOIR OF DR. DALTON, AND

" Nearer determination of the law hy which the quantities
of the alkaline earths, which enter into rest and neutrality
with muriatic and vitriolic acid, increase or diminish in
arithmetical progression. § XXIV., p. 34.

"A. As we cannot completely ascertain the law by which
the terms of the two series of numbers obtained by experiment
proceed, we must try another source of information, to the ob-
taining of which the series itself which the determining element
of muriatic acid makes with the alkaline earths, gives us an
opportunity. As the differences of the quantities in § XXII.
are a product of a quantity 6 with an odd number, it is
possible that as many terms are wanting as there are odd
numbers between 3 and 19, and even that other terms may
lie beyond the term «+196 or -^4-19. Suppose, then, that
this series were complete, namely, 'a, a-\-h, a-\-Zb, a-\-bhy
a^lb, a+9^ a+Il^ a+136, a+156, 0+176, a+196,
a + 21&, a + 236, &c., the masses of the elements which enter
into neutrality with 1000 parts of muriatic acid would be the
following : —

a =734 = 734

a + i = 734 + 124J = 8581

a + 35 = 734 + 3.124J = 1107J

a + 55 = 734 + 5.124J = 13561

a + 75 = 734 + 7.124i = 1605^

a + 95 = 734 + 9.1241 = 1854^

a + 115 = 734 + 11.1241 = 2103^

a + 135 = 734 + 13.124J = 2352J

o + 155 = 734 + 15.124J = 2601J

a + 175 = 734 + 17.124^ = 2850i

o + 195 = 734 + 19.124J = 3099J

a + 215 = 734 + 21.124J = 3348J

a + 235 = 734 + 23.124J = 3597J

&c. &c. &c.

HISTORT OF THE ATOMIC THEOKY. 197

" Now let us suppose that these alkaline earths, which are
partly real, partly possible, and designated by the above num-
bers, entered with muriatic acid into such neutral combina-
tions as would decompose with a neutral compound out of the
series § XXIII., such as the magnesia salt, by double affinity
either positive or negative (see Pure Stoechiometry. Theor.
3, coroll. 3. Introd. definition 16), then only that neutral
compound is excepted which the muriatic acid makes with the
alkaline element of the neutral salt which we have chosen in the
series XXI II., or the combination which is also taken with
the magnesia salt. But according to experiment 6, coroll.
2, in the Pure Stoechiometry, in the decomposition by double
affinity, out of three proportions the fourth may be deter-
mined. Let us suppose, then, that all the mentioned actual
and possible neutral combinations, magnesia salt excepted,
decompose with sulphate of magnesia (bitter salt) either
positively or negatively, so that each constituent is placed in
a state of rest (Pure Stcech. Theor. 1, coroll. 1); then we
may find how many measures of each of the real and possible
elements are wanted for 1000 parts of the vitriolic acid mea-
sures. (Pure Stoech. Introd. def. 14.)

" B. The first neutral compound in the series, § XXII., is
an actual one, namely, alum salt, where 734 parts of alumina
stand in neutrality with 1000 parts of muriatic acid. If this
neutral or middle salt decomposes with sulphate of magnesia
by double affinity, then 858^ parts of magnesia must be con-
tained in the sulphate of magnesia, because the proportionate
quantity in the magnesia salt is as 1000:858, or rather
1000: 858^. § XXII. Now the proportionate quantity
in the sulphate of magnesia is 1000:616 (§ XIX., XXIII.)
and 616 : 1000=858^: 1,394 ; that is, if 616 parts of mag-
nesia insist on rest with 1000 parts of vitriolic acid, the same
must occur between 858^ parts of the first and 1394 parts of
the latter; therefore when alumina salt and magnesia salt
decompose, 1000 parts of muriatic acid dissolve with 868 J

198 MEMOIll OF DJl. DALTON, AND

parts of magnesia, and 1394 parts of vitriolic acid with 734
parts of alumina; the proportionate amount of the alum
formed will then be 1394 : 734=1000 : 526, which is not the
proportion of the neutral but the common alum. (§ XXI.)
The quantity of the alkaline earth in common alum belongs
accordingly to the series § XXIII.

" C. But when, in the decomposition of the first neutral
compound, where muriatic acid is the determining element with
sulphate of magnesia, the amount of the vitriolic acid is 1394,
it is so in all subsequent possible decompositions which the
neutral compounds of the other actual and possible elements
of the series § XX 1 1, make with the sulphate of magnesia,
let these decompositions be positive or negative. (Pure
Stoech. Theor. 3, corolL 3.) The quantity, then, of real
and possible elements which belong to 1000 parts of muriatic
acid belong to 1394 of vitriolic, and the following proportions
are obtained for the compounds where the vitriolic acid be-
comes at rest with the real and possible elements (Pure
Stoech. Theor. 1, corolL 1), all of which obtained by expe-
riment except the common alum are neutral.

1394 :
1394 :

734
858J

1394 :

1107J

1394 :

13564

1394 :

1605J

1394 :

; 1854i

1394 :

; 2103J

1394 :

; 2352|

1394 :

; 2601i

1394 :

; 2850J

1394- ;

: 30991

1394 ;

; 3348J

1394 :

; 3697i

1000 :

526

1000 :

616

1000 :

796

1000 :

973

1000 :

; 1152

1000 :

1330

1000 :

; 1508

1000 :

: 1687

1000 :

1866

1000 ;

; 2045

1000 ;

; 2224

1000 :

; 2402

1000 :

2580

HISTOET OF THE ATOMIC THEORY. ^ 199

§ XXV.

" A. When we look on all these numbers found, viz., 526,
616, 796, 973, &c., as quantities of the elements which
are at rest with 1000 parts of sulphuric acid, we obtain a
series, the law of which soon appears to us. Let us first
subtract the first term from all the succeeding, and we obtain
the following differences, which may be expressed in various
ways :—

616 —

526

=

90

=

90

rr

90

796 — -

526

=

270

=

270

=

3.90

973 —

526

=

447

=

450

—

3

=

5.90 — 3

1152 —

526

=

626

=

630

--

4

=

7.90 — 4

1330 —

526

^

804

=

810

—

6

=

9.90 — 6

1508 —

526

=

982

=

990

—

8

=

11.90 — 8

1687 —

526

=

1161

=

1170

—

9

=

13.90 — 9

1866 —

526

=

1340

=

1350

—

10

=

15.90 — 10

2045 —

526

=

1519

=

1530

— -

11

=

17.90 — 11

2224 —

526

=

1698

=

1710

—

12

—

19.90 — 12

2402 —

526

=:

1876

=

1890

—

14

=:

21.90 — 14

2580 —

526

=:

2054

=

2070

—

16

^z.

23.90 — 16

" B. The law by which the differences of the actual and
possible alkaline earths increase in relation to vitriolic acid is
then so far made out that it follows from the product of a
number which is here 90 with the consecutive odd numbers ;
we may consider the numbers which are to be subtracted, such
at 3, 4, 6, 8, 9, &c., as nothing, because the greatest error
that could be caused is only 4iiy=TH=0.0066, or iiiV«nj ; but
even this is not necessary, because the numbers themselves
proceed in distinct order, as the series shews; and if we
inquire, as in § XXII., into the manner in which these
numbers progress, we observe that if three of them increase

200 MEMOIR OF DR. DALTON, AND

by odd numbers, the succeeding four increase in the ordinary
way by one, and so alternately ; for example.

3

=

—

3

(3

+

1)

=

—

4

(3

+

3)

=

—

6

(3

+

5)

=

—

8

(3

+

6)

=

—

9

(3

+

7)

=

—

10

(3

+

8)

=

—

11

(3

+

9)

=

—

12

(3

+

11)

=

—

14

(3

+

13)

=

—

16

(3

+

15)

=

—

18

(3

+
&c.

16)

&c.

—

19

" These quantities accordingly proceed in arithmetical pro-
gression down to the most insignificant fractions, as we may
see by a glance at them.

" The quantities in which the alkaline earths enter into
neutrality with muriatic acid are terms of an endless series,
which increase by the product of a determinate quantity
with the consecutive odd numbers. The same thing occurs
with the alkaline earths in relation to sulphuric acid, only
that in this case a quantity must be taken from the terms of
the last series, the first three excepted; this quantity in-
creasing also in progression,

§ XXVI.

" A. After finding out the law by which the quantities of
the alkaline earths increase towards the two acids (sulphuric
and muriatic), it becomes necessary to form the series them-
selves, that we may see clearly the correctness of the propo-
sition advanced as a hypothesis ; for if it is done rightly the
proposition ceases to be a hypothesis. We shall designate the
terms that are wanting in both series by a star, and the

m

HISTORY OF THE ATOMIC THEORY.

201

elements which produce with acids a very violent heat when
freed from their air, for example, lime and magnesia, by A ,
as the sign of fire.

Muriatic Acid .

...

a =

= *

r34,

6 =

= H^

=

124i.

Alumina...

a

==

734

+

^n

734

A Magnesia..

a

+

b

=

734

4-

*^

=

858i-

A Lime ....

a

+

Sb

=

734

+

M^

=

1107i

#

a

4-

5b

=

734

+

^^^^

=

1356^

«

a

4-

n

=:

734

-h

i^,^

=

1605i

«

a

+

95

==

734

+

^.^jO.

=

1854i

♦

a

+

lib

=

734

4-

X-L-giP

=

2103i

♦

a

+

136

=

734

+

i^^±JL

=

2352i

«

a

+

156

=

734

+

ii:A4.S.

=

260U

♦

a

-h

176

=

734

+

i7|ia

=

2850^

Baryta ..

a

+

196

=

734

4-

Jjaj|^tJL

=

3099i

•

a

+

216

=

734

+

Al:*A^

=

3348^

♦

a

+

236
&c.

=

734

4-

8 ?•?*»

&c.

=

3597i

" B. Before we set down the quantitative progression in the
case of vitriolic acid, we must first inquire if the quantity of
alumina in neutral alum belongs to this series; it is 1053.
Let us subtract 526 from 1053, and we obtain 527 ; now 527 =
640—13=6.90—13, and consequently 1053=5264-6.90—13.
But as the series determined by vitriolic acid proceeds by the
uninterrupted odd numbers, and no neutral alum can be found
in decomposing by double affinity, the quantity 5264-6.90 — 13
does not belong to this series. We must take it, however, in
the meantime into the series, because it belongs to the quan-
ities which enter into neutrality. We shall, however, put
such in brackets, as must happen when considering the quantity
of alumina in common alum, if it is not a legitimate member
of the series, and capable of double affinity.
2D

202 MEMOIR OF DB. DALTON, AND

No. 2.
Sulphuric Acid a = 526, 5 = 90

Alumina., a =526 = 526

A Magnesia. 0+ b =526+ 90 = 616

A Lime . . , a-\- Sb =526+ 3.90 = 796

* a+ 5b — S =526+ 5.90 — 3 =973
Alumina..(a+ eb —13) =526+ (6.90 — 13) =1053

* a+ 75 — (3+ 1)=526+ 7.90 — (3+ 1)=1152

* a+ 95 __ (3+ 3) =526+ 9.90 — (3+ 3) =1330

* o+lU_(3+ 5) =526+11.90 — (3+ 5) =1508

* a+135— (3+ 6) =526+13.90 — (3+ 6) =1687

* a+156 — (3+ 7) =526+15.90 — (3+ 7) =1866

* a+175 — (3+ 8) =526+17.90 — (3+ 8) =2045
Baryta., a+195 — (3+ 9) =526+19.90 — (3+ 9) =2224

* a+215 — (3+11) =526+21.90 — (3+11) =2402
^ a+235 — (3+13) =526+23.90 — (3+13) =2580

&c. &c.

" C. If we convert the differences into simple consecutive
odd numbers, the quantity of the determining element and
all the terms of the series have only to be divided by b, and
we receive :

No. 1.

Muriatic Acid, ^ ^^a i 2*9 Muriatic Acid, ^+8
4 «=734, b=H^ ^_ ^S^^g

Alumina.. -? = _»i_ := 5 + |||

A Magnesia, -f- + 1 = ^»f = 6 + If^

A Lime f + 3 = 1^- 8 + H ?

13564 1 n _J_ ?A?

124i ^^1" 249

1605i 1 O _1_ ?^3

1244 1-4 -f- 249

18544 1 4. _i. 2U

1244 ^^1 249

2 1£34 Ifi _!_ ^1^

T244 AU -f- 2 49

a

~b

—

a
b

+

1 =

a

b

+

3 =

a
b

+

5 =

a
b

+

7 =

a

b

+

9 =

a
b

+

11 =

HISTOBT OP THE ATOMIC THEOBY. 203

T84T — ^° "T 5T9

♦-^+13 = -?^Z=18 + ^

• _^ + 15 = i^U = 20 + i^J

j( *" 1 1*7 _ 88901 __ OO _l_ *23

• -r + 1/ — -iTfT — ^^ T m

Baryta.. ^ + 19 = \\\\* = 24 + |||

• -^ + 21 = ^'.W = 26 + |f2

• -^ + 23 = ^i|^ = 28 + If;

No. 2.

Further-
Vitriolic Acid, a=526, 6=90 Vitriolic Acid=l 1^

Alumina. _|_ — 5^6 — 5 -f. ^

Magnesia _|_ 4. 1 zi Vo' = 6 + H

Lime . . _i_ + 3 =: VV = 8 + ii

♦-f+5 i- =SVz=10 + if

Almnina. [_^ + 6 — V] = ['"H^] = [H +il]

* ^ + 7 — '-^' = 'W = l^ + U

♦ -f- + 9 — ^4^* = »«o = 14 + ii

♦ -f- + 11 — '^4^ = >ii- = 16 + «

• -J- + 13 — i^ = '-H' = 18 + -H

# ^ + 15 — LA±i-' = '-H-* = 20 + -H-

* -r + 17 — ^H^ zz •K^ = 22 + -H

Baryta.. -2- + I9 _ L3+£.> = .^* z= 24 + -H

♦ _|- + 21 — !A+i_L> = '^g* = 26 + n

♦ _j- + 23 — '-^^^ = »-H° = 28 + i^

&c. &c.

204 MEMOIR OF DR. DALTON, AND

" D. When the numbers in the last series are compared with
those found by experiment, they are found to agree perfectly,
as far as regards alumina, lime, and magnesia. On the other
hand, the amount of baryta in the sulphate is 2224, but in
§ XIX. 2226. No doubt the difference comes from the
greater difficulty in finding the point of saturation in the case
of this earth than in the case of the others, when combining
them with sulphuric acid. At the same time, the supposed
error is so small that it may be left out of consideration, for it
amounts only to -^i^^ or 0.0009 or to^o^o o, which is a diiference
that may be reckoned as nothing. It must be remembered
that decimal fractions only are used here.

" E. Now if the quantities found by experiment exactly fit
into the series, if all the terms of these series entirely corre-
spond to the possibility of double affinity, if even a quantity
which is capable of neutrality, but not of double affinity, is
banished out of one series by the rule of the series ; further
if one series becomes possible only through the other, the
proposition is absolutely certain, that the quantities of the
hitherto known alkaline earths which enter into rest or
equilibrium with sulphuric and muriatic acids are terms of
an infinite series in arithmetical progression, each of which
proceeds according to its own law.

' ' G. Shall we then conclude from the laws of the two series, in
which so many terms are wanting, that there are many alkaline
earths existing in nature ? So far as probability and possibility
are concerned it is a fair conclusion, especially since the know-
ledge of magnesia and baryta are the property of only the last
half century. If they had not been discovered until after the
study of the stoechiometric sphere had commenced, the second
and eleventh term of every series would be wanting, and a *
substituted, and besides it would not have been possible, with
such a small number of terms to have found out the law.
Who knows if there are not other elements in existence which
interrupt the last series as neutral quantities, precisely as with

HISTOKY OF THE ATOMIC THEORY. 205

the alumina ? But if we should conclude from the law of these
series that the existence of the failing elements is necessary,
then we should commit as great an error as if we were to
conclude that a planet must exist between Mars and Jupiter,
because it corresponds to the law of the distance of the planets
from the sun.

" H.. The use of these series of quantities is not small, for if
we know only the first member and are acquainted with the
law, we find all the other members and all the proportionate
quantities with the greatest exactness, and who does not know
what differences there have hitherto been in the numbers re-
presenting the proportions? How many uses shall we find
also in chemical analysis for series of this kind, of which
probably there are many, and to what perfection might it not
bring the chemical system, if they could be used as tables of
affinities ?

^* The two series of quantities, 1 and 2, § XXVI., are
really quantitative series of the affinity of alkaline earths
towards muriatic and sulphuric acid. Page 51.

Page 56. " Determination of the decomposing forces, §
XXVIII.

"A. The experiments now detailed enable us to state the
proposition that affinities are as the masses.

" C. P. 61. If now in these cases of affinity the attracting
forces of the elements are as the masses of the elements, and we
take 3099 as the attracting force or affinity of baryta towards
muriatic acid, the numbers 1107, 858, 734, or the attractive
force of the elements represented is quite unaltered towards
muriatic acid, on the other hand we must calculate the affinity
of those earths to sulphuric acid from the numbers given
and the proposition adopted. According to the proposition,
1000 : 1394=3099 : 4320 and 1000 : 1394=734 : 1023, in the
same way 3099 : 734= 4320 : 1023. If, then, the attractive
power of baryta towards muriatic acid is 3099, towards

206 MEMOIR OF DR. DALTON, AND

vitriolic acid it is 4320, and if alumina acts towards muriatic
acid with the force of 734, and towards vitriolic acid with a
force of 1023 forming common alum, in the same manner
the baryta is attracted with a force of 4320 towards vitriolic
acid, forming heavy spar, and so the power by which this
acid forms common alum is only 1023. If we inquire into the
affinity of the other alkaline earths towards vitriolic acid by the
rule of three, we obtain for lime ^-H^H^^=1543, for magnesia
iif^vs^—Ugg^ jf^ then, in the cases of double affinity given,
we put instead of the quantity the attractive force by which
one element works on another, we obtain, according to the first
theorem of the ' Pure Stoechiometry,' as follows : —

No. 1.

Baryta. Muriatic Acid.

3099 Baryta Salt. 3099

4320 734

;5$-*

^

%

V

N*^"

%.

734 4320

1023 Common Alum. 1023

Alumina. Vitriolic Acid.

<t J) * * * jjj ^Q^ J |.jjg |.^Q positive or decomposing
elements are 4320 and 734, the negative which hinder the
compound are 3099 and 1023, consequently 4320-1-734=5054
the whole positive or furthering, and 3099+1023 =4122 the
whole negative or hindering power. * * * " The difference
(equal to the power, as he says) =-f 932 is positive.

He then endeavours to shew in the same way, page 171,
&c., that " The masses (quantities) of the three alkaline salts,

HISTORY OF THE ATOMIC THEORY. 207

which enter into neutrality with an equal amount of vitriolic or
muriatic acid, are the three first terms of two series, of which,
that which belongs to muriatic acid proceeds by the odd
numbers without interruption, and the other is the product
of a quantity with the numbers in regular succession."

Page 167. " When an aqueous solution of vitriolic salammo-
niac is poured into a solution of muriate of lime, an abundant
precipitate is caused, which is completely formed gypsum ; if
the exact quantity of the salammoniac solution has been used
which is necessary to complete the precipitation, the liquid
above the precipitate contains nothing but perfectly formed
common salammoniac. But the proportion in the salt is
1000 : 1107^, and to 1000 of the chloride are to be calculated
889 parts of the volatile alkali ; now let us inquire how much
of the vitriol is needed for 11 07 J parts of the lime, the pro-
portion of the last to the first is 796 : 1000, consequently
1107i parts of lime demand i^7%V^^=^W9¥^=:1394 parts
of vitriol, which belong to the 889 parts of the volatile alkali.

He gives a list, page 279, of " Proportional quantities
of neutral compounds which decompose each other, when
entirely deprived of water J* ♦ * » » " In each of these
cases it is only necessary to add the numbers representing the
quantities standing against each other horizontally, by which
the power of the affinity is estimated, and we receive the
neutral quantities which decompose each other, and conse-
quently their proportion."

Salammoniac Vitriol. Common Salt.

689 + 1000 : 960 + 717 = 1689 : 1677

Salammoniac Vitriol. Common Salt.

638 + 1000 : 960 + 717 = 1638 : 1677

Magnesia Salt. Vitriolized Potash.

868 + 1000 : 2239 -f 1394 = 1858 : 3633
&c., &c., &c. ; this is from a list of 28 : the second and third
are supposed hydrous.

208 MEMOIR OF DR. DALTON, AND

Then we have, p. 284, '^ Proportional quantities of neutral
compounds containing muriatic acid, considered as an-
hydrous, when decomposed by vitriolic acid J' Also, " Pro-
portional quantities, when the neutral compounds which
vitriolic acid makes with the alkaline salts and magnesia
are decomposed negatively or by free muriatic acid" P. 293.

At page 190, he says, that the affinities are as the amount
of the combining proportions, and here also the atomic weights
of ammonia, soda, and potash, are such as to lend some
countenance to it. The series, however, is still considered
the most important thing, and he finds afterwards, in the vol.
for 1800, that smaller weights may precipitate larger ones.

These inquiries were continued with great labour, and in
his work " On the newer subjects in chemistry," we have
many attempts to define the relations between the acids and
bases. In the vol. for 1798, we find him fixing the relation
between the metals and some of the acids, but always on the
same plan.

At page XV. in the preface to the vol. for 1800, he says,
" To follow an author step by step, in a path trodden by him
alone, and to judge him with fairness, is not in the power of
every one, still less can it be done by merely reading through
his book."

Page xxiii. Again, " Whoever looks on the remarkable
order, which reigns in the quantitative proportions, by which
every kind of substance has a peculiar quantitative character
with respect to another, as a mere play of figures, or as a
mere accident, would only show his complete ignorance of the
whole structure of stoechiometry, but would be indemnified for
it by a still greater degree of philosophical faith; for it requires
much more credulity to believe in so many accidents, than is
needed to perceive that the Lord of nature has not only qua-
litatively but quantitatively endued it with the most wonderful
order, both in great things and in small."

Another extract from the same, page 206, " In the simpler

HI8T0EY OF THE ATOMIC THEORY. 209

uffinities every kind of neutralizable substance has its own
quantitative law of affinity, because the amount of affinities
among the alkalies may be expressed by the mass, that of
the acids by the substratum (that is, the body of which the
oxygen of the acid is an oxide) ; but this is not found to be
the case either with the metallic or nonmetallic combustible
elements."

What then did Richter attain to is the question to be now
answered. In the extract from the preface he raises the study
of atomic chemistry to a science, and gives it a name. This
is itself no small honour. The chemists before him had
certainly not been gifted with such a clear appreciation of the
importance of the study. We find that Richter has made it
the leading object of his life to elucidate the laws of com-
bination; as a young beginner, making it a subject of his
inaugural dissertation, and looking forward to the time when
be might have opportunity to prosecute his investigations.
The word stcechiometry is preserved in Germany, with us it
is too abstract for daily use.

The first definition of stoechiometry has appended to it
six experiences (erfahrung), most of them with corolla-
ries (zusatz). The reading becomes, therefore, exceedingly
cumbrous, the words are marvellously multiplied, pure abstrac-
tion is aimed at in every step with painful strains, as it would
appear, or perhaps only caused by a mathematical habit of
mind too exclusively followed. In this way the few truths
that we still hold to, and which are contained in the book, are
to oniamented and overdressed as to have been to most
persons entirely hidden under the richness of the elaboration.

He expresses his belief that the smallest portions of a body
are of the same composition as the largest. He says that the
affinity exists in every particle. Then adds that every piece
must have the same composition. His own words are very
cumbrous, but this meaning is distinctly there. This was
the illustration which Dalton afterwards used on the same
2£

210 MEMOIR OF DR. DALTON, AND

subject, but it was expressed in clearer words, and still earlier,
by Higgins. This idea leads directly to the atomic theory and
theory of equivalents. Here it is not followed out.

The sixth experience of first definition gives the theory
of reciprocal saturation, when double decomposition takes
place in solutions. This is the discovery which has been at-
tributed to Wenzel. Let us translate his formulas into the
present symbols by an example : —

A^O NO5— NO5, NO5+KO SO3— SO3, SO3
^NOg'+KO SO3— SOa+SOg+A^ONOs— NO5.

He says the products of neutral salts are nearly without
exception neutral, but nevertheless sees enough to form a law.
Wenzel, with similar results, had not seen a law.

He endeavours to shew the relative amount of force exerted
by different substances when decomposition takes place,
but he gets no farther than the fact that certain forces are
equal, some must be greater, and others must be less.
In this district of inquiry, an example of which may be
found in Theorem I., what appears to be the enunciation of
an important law, frequently turns out to be the mere expres-
sion of a common-place, giving no information to the chemist.
Such laws being in a certain sense universal, they are now
left out of chemical works, as the mind can readily draw the
conclusion for itself, if the opportunity offers.

He then shews the method of obtaining the proportion of
the elements in a compound. This had been pursued with
great care by Wenzel.

The great aim of Richter is not perceived in reciprocal
proportion, but in the attempt to make the combining
numbers of all bodies a series in arithmetical progression, and
so to bring number, quantity, and order into the arrangement
of the elements. In the series which he has formed, I think
we may say that he has failed to prove his point. The
numbers he had were too few, and the mode of obtaining the
order is by no means satisfactory. There is, however, a

HISTORY OF THE ATOMIC THEORY. 2 1 1

great probability recognised by most chemists of the existence
of an order in which the elements are related to each other.
If this order should ever be found to be similar to that iTvhich
Richter has indicated, we must do the greatest honour to his
genius, although we cannot even now, when it stands before
us, say that it is a discovery, or that it has any value at all.

The discovery of reciprocal proportion is given by no one
before Richter as far as I know, but he himself does not
speak of it as a discovery, but as a well-known fact, with
which he was familiar before he wrote his inaugural disserta-
tion. We find in the preface that it was well known that
neutral salts gave neutral results on decomposition ; this
Richter has put formally amongst the laws of stoechiometry,
and given it rank amongst chemical truths. He deduced from
it, as he himself says, that there must be ** distinct propor-
tionate quantities amongst the component parts of neutral
salts," and he strove hard to bring all combinations under
number and quantity. The knowledge of this fact seems to
have first set in motion his stoechiometry; instead then of
being the point which he gained, it is the point from which
he starts, according to his own account. He does not,
however, seem to have seen the reason for it, nor its general
bearing in chemistry, otherwise it could not have been left for
Fischer to shew that the combining number of an element
would fit its combination with every other element.

The mode in which he obtains the relation of the combin-
ing weights of the earths to each other is remarkably self-
delusive, but at the same time exceedingly ingenious. They
are given at length, so that every one may compare for
himself.

He endeavours to find out a similar relation between the
atomic weights of the alkalies, and readily does so. He is
led away by the numbers observed to mistake them for repre-
sentations of actual force, and so calculates in a relative and
abstract way the force needed for decomposition. This is

212 MEMOIR OF DR. DALTON, AND

very characteristic of him, but unfortunately he has gone on
a wrong assumption.

He has evidently been a man of great quickness, at the
same time apparently of haste ; he has enunciated the most
beautiful truths, and left them untouched for worthless specu-
lations, which seemed to need more ingenuity, almost leaving
us to doubt how far he understood his own writings. We
must, however, give him the honour of understanding what he
wrote, smaller honour we can give no man. Still it is per-
fectly clear that if his theory were as fully developed in his
mind as we with our superior opportunity can now see to be
deducible from his words, men would have understood him,
and the process would have been continued, but neither
did he make any advance, nor did he teach others clearly,
although the young Berzelius was much excited to curiosity.

It certainly is difficult to tell how discoveries grow, often
impossible to tell who is the discoverer ; but this we may con-
sider a fair rule, not always easily applied, it is to be confessed,
that he is a discoverer who sees distinctly the full bearing of
his discoveries ; when this does not happen there is a difficulty
in giving that man the place due to him. It is clear that
Richter, like some others already mentioned, had fundamental
principles which would have led him to the atomic theory ;
but he has evidently been led by foregone conclusions, and
the law of planetary distances has been floating in his mind
and misleading him, when seeking for the diiFerences in the
combining weights of bodies.

The discovery of reciprocating proportion was a very im-
portant and memorable one, although the scientific world did
not recognise it, another among the many proofs that scientific
men are subject to the same bigotted attachment to the laws
they have learned, as that class of men hitherto most blamed
for bigotry, nor is there any bigotry more engrossing than
that which appears to the possessors to be upheld by experi-
mental proof. Who discovered this important fact, it is still

HISTORY OF THE ATOMIC THEOEY. 2 1 3

left unascertained ; as the expression of a law it is Richter's,
but as a fact regarding neutral salts the author appears not
to be known.

Among the many disputes on this point it is rather surprising
that.people should speak without reading the authors they
discuss. The supporters of Wenzel have not read him, the
supporters of Richter have overlooked his own writings and
his own confession, as it appears to me in the preface. But
as I give the words every one may judge for himself.

In proceeding with his inquiry one cannot but admire the
energy and activity of Richter's mind, and his enthusiastic
desire to prove the beauty of the arrangement of creation ; it
is clear that he lost his way, and spent the greatest part of his
energy on a subject which could not with his data lead to
great results, and which even now gives us no help, and
which was not the next step wanted in chemistry. The
science was straining after definite laws, it had none ;
Richter, with his one great law, might have done wonders,
had he only seen its value; he might have found on ex-
amination that it was, properly speaking, an inference from
another much more general law, and would have then ex-
pressed himself in universal terms. But Higgins had
expressed himself much more clearly as to combination be-
fore him, as already shewn, and only failed because he had
not seen it to be a general law.

Richter attempted to give the proportion of the acids to
bases as an expression of affinity, but this had been already
attempted by Kirwan, and was shewn to be unsuccessful.

As a general summary of Richter*s most important work,
we may say, he found that there was a certain quantitative
relation between all bodies, and he made out the laws so far,
that when he knew the quantitative analysis of a salt, he
could tell its quantitative decomposition with another, but
he never saw it with sufficient clearness to be able to express
the combining quantities each by its own distinct number,

214 MEMOIR OF DR. DALTON, AND

nor does he appear to have ever proceeded far enough to be
able to assign a cause for the phenomenon, or to connect it
with any fundamental idea.

He was the founder of the systematic study of stcechiome-
try, he was an illustrator of one of its important laws, apd a
defender of regularity in nature. His scientific life was
laborious, his love of science sincere, and in all respects he
seems to have been a man of high character. After reading
his works, and coming occasionally on a sentence which
makes us for the moment believe that he has discovered a
greater law than we can give to him, and finding that during
his whole life he was just on the point of the present atomic
laws, one feels that he was perhaps the only man that deserved
to discover them, having given himself up entirely to that
purpose. It is with regret, therefore, that I leave him also,
another combatant who died before the victory.

It has been said that Dalton had read Richter, and had
never acknowledged his claims. It is a melancholy thing to
see men of talent and learning so readily distrusting their own
class, as if dishonesty were so common. I might say the
same of Richter, that for more than ten years he continued
to publish on stoechiometry, and never once mentioned Hig-
gins, but his whole works shew that he did not see Higgins's
writings, or he would have probably got less involved than
he did. We learn from Dr. Henry that Dalton had seen
Richter's results on reciprocal proportion,* and had received
assistance from them, but although they may have assisted
him in proving his laws, Richter could never have given him

* Dr. Thomson had said the contrary; but let us take Dr. Henry's informa-
tion, as being an intimate friend. Dalton could not have seen Richter's whole
works, but probably an account of them. They are scarce in England. It
cost me a good deal of trouble to get one, even in Germany. The British
Museum does not possess a complete copy. Dalton certainly had not read
Higgins; and although Dr. William Henry had a copy, we may conclude from
his son's work that he had not seen in it the Atomic Theory, as he seems not
to have thought it necessary to mention its existence to Dalton.

HISTORY OF THE ATOMIC THEORY. 215

fundamental ideas. These are much wanted in Richter^s
chemistry. Richter's cotemporaries did not obtain the atomic
theory, although some were students of his work. Berzelius
himself did not obtain the atomic theory from Richter,
although the most illustrious of the students of Richter's
books. Dalton then could not have obtained it, and the
direction he takes is perfectly different, the road he went
quite clear, and the result he came to entirely distinct from
that aimed at by Richter.

In such early days it required a mind of a high order to see
as Richter did into the great necessity of permanent laws,
and the great structure he raised to make the inquiry shews us
that he saw its importance. Had chemists been accustomed
to study the works of their own class, such books as his
would have rapidly produced results, but the history of the
matter speaks ill for the apathy of the men of even that
period, and well for his untiring energy and devotion.

216

MEMOIll OF DE. DALTON, AND

CHAPTER X.

FISCHER, BERTHOLLET, PROUST, &C.

When Richter had illustrated the action of neutral salts,
and had seen somewhat dimly reciprocal proportion, Fischer
(Ernst Gottfried) saw it in a much clearer light, and put it
in a more practical form. He took Richter's analyses, and
shewed that a constant quantity of one base would unite to
a constant quantity of an acid, and that the numbers in all
would be reciprocal. Such, one would call the true discovery
of reciprocal proportion, were it not, that in this case, the
intellectual labour required does not seem great.
Fischer's table is as follows : —

ACIDS.

427 Fluoric.

677 Carbonic.

706 Sebacic

712 Muriatic.

755 Oxalic.

979 Phosphoric.

988 Formic.

1000 Sulphuric.

1209 Succinic.

1405 Nitric.

1480 Acetic.

1583 Citric.

1694 Tartaric*

It is explained so ; *' When any substance is taken from
one of the two columns, ex, gr., potash from the first column,
where the number 1605 stands, then every number of the
second column shews how much of that substance is needed
to neutralize 1605 of potash." The same thing may be said

* Schweigger's Stoechiometrische J^cihen. Page 45.

Alumina 525

Magnesia 615

Ammonium 672

Lime 793

Soda 859

Strontian 1329

Potash 1606

Baryta 2222

HISTORY OF THE ATOMIC THEORY. 2 1 7

if we begin with the second column. In other words, the
numbers attached to the bases indicate the amount which
unites to the acid numbers (or proportions represented by
them).

But we cannot say more of Fischer than that he made
plainer Richter's law.

In 1803, immediately after the last of Richter's periodical
publications, but ten years after the publication of Pure
Stccchiomctry, appeared the Essai de Statique Chymique
of Berthollet.*

There is no stronger proof of the want of influence of all
preceding inquirers on this subject than the existence at this
period of Berthollet's essay, and the effects it had on the
followers of the science, who could neither have understood
nor believed the earlier, when they listened to the later with
so much attention.

In Berthollet's Essai, we find the following sentences.

Chapter II. 13. " The chemical action of different sub-
stances is excited, not only in the ratio of their affinity, but
also in the ratio of their quantity; one immediate consequence
is, that chemical action diminishes in proportion as saturation
advances.

14. " It also follows, from this law, that a substance which
is in solution in a quantity of liquid greater than is necessary,
is retained therein by a more powerful action, and that, on
the contrary, the superfluous quantity of the liquid is sub-
jected more feebly to the affinity of the dissolved substance
than is required for solution. It will be seen, therefore, that
the general law which I have announced is, in this instance,
only modified by the circumstance which limits the quantity
of liquid that can exert its action simultaneously."

Then we have this extraordinary sentence, proving that so
far from the subject of the atomic theory being clear, even
fc the doctrine of proportion had not made its way.

^H * The English translation by B. Lambert, 1804, it here quoted.

I

218 MEMOIR OF DR. DALTON, AND

39. " Some chemists, influenced by having found determi-
nate proportions, in several combinations, have frequently
considered it as a general law that combinations should be
formed in invariable proportions ; so that, according to them,
when a neutral salt acquires an excess of acid or alkali, the
homogeneous substance resulting from it is a solution of the
neutral salt in a portion of the free acid or alkali."

" This is a hypothesis which has no foundation, but a dis-
tinction between solution and combination."

42. " It follows, from what has been said above, that the
most powerful, as well as the weakest chemical action, is
exerted in the ratio of the reciprocal affinity of the substances,
and of the quantities within the sphere of activity ; that the
action diminishes in proportion to the saturation, and that
there is no point at which it determines the proportions, but
that the limits of these proportions in the combinations which
it forms, and those of its power, are to be sought for in
the forces which are opposed to it. Finally, two effects of
chemical action must be distinguished, that by which it pro-
duces a reciprocal saturation, and that which causes a change
in the constitution."

47. " Hence it follows, that in the comparison of the acids,
the first object which will fix the attention is the power with
which they can exercise the acidity which forms their dis-
tinguishing character. Now this power is estimated by the
quantity of each of the acids which is required to produce the
same effect, that is to say, to saturate a given quantity of the
same alkali.'*

Beautiful and ingenious as Berthollet's investigations into
affinity are, he, too, missed the line of thought which was to
produce the greatest discovery known to chemistry, but it was
not carelessly passed over. His inquiries had led him into
some very interesting qualities of bodies, the power of quantity
to overpower feebler quantities in certain cases, and the capa-
city of bodies to decompose others according to the nature of

HISTORY OF THE ATOMIC THEOEY. 219

the compound formed. For example, a salt, say an oxalate,
decomposes a salt of lime, not because the oxalic acid has
such a powerful aflSnity for lime, but because the oxalate of
lime being insoluble falls, following the physical qualities of
the compound ; oxalic acid too decomposes common salt, not
from a greater affinity, but because muriatic acid being vola-
tile, has a way of escape, whilst oxalic acid has not, and
so on.

These and similar reasonings took up such a large portion
of his field of vision, that he denied, as we have seen, definite
proportions, and, of course, atomic theories and equivalents
could never be received from BerthoUet. He denied definite
proportions in the present sense, but, as Berzelius says,
allowed them, although within certain limits. This would
imply proportions of a rather indefinite kind. In the
" Memoires de la Societe d'Arcueil," he even gives laborious
analyses tending to fix the proportions of the elements in
certain bodies. This was chiefly from the point of view that
distinct bodies had determinate and constant composition,
which, of course, it would have been too late to deny.

BerthoUet did, nevertheless, put a drag on the inquiry
into the general question of proportion, and from his
superior position commanded great influence. It is in this
state we find the science, then, when Dalton came to it.
It may be said that the state of the science comprehended all
that was published, and this is in a larger sense true, and con-
stitutes the base of a final opinion of a discoverer's merits; but
the state of what seemed to be the well-grounded science, as
far as the leading men held it, was rather that of BerthoUet
than any others, the leading innovators were obscure, and never
indeed became magnates in the scientific world. These latter
commanded to all appearance in the capital, whilst the real
power was getting prepared in the provinces.

Berthol let's essays must always stand as the greatest proofs
of the reality of Dalton's achievements. Whatever men may

220 MEMOIR OF DR. DALTON, AND

have built before, this is the existing ground on which Dalton
had to raise his edifice.

To some extent this may be reckoned questionable, as the
discussion as to the definite proportions of compounds was
going on with Proust, a strong supporter of this doctrine, but
this exception only shows that the differences of opinion were
raised, not on the great theory, the history of which we are
discussing, but on the simplest preliminary facts ; the laws
themselves did not appear in the discussion from the cause
already given, viz., virtual non-existence, except in a state of
possible evolution from laws which themselves were not fully
proved.

I shall now give those sentences from Proust's writings
which seem most nearly to affect our subject.

* " As to those which have been announced by Thenard,
I will not contest results obtained by a chemist who knows
how to operate with that exactitude which characterizes a con-
summate worker. I will say, however, without attaching any
importance to my opinion, that in considering this almost
general law of nature which offers us everywhere only one or
two terms of oxidation of metals, and from which, in our arti-
ficial imitations, we cannot free ourselves, I fear that the six
terms which he recognises are not all sanctioned by nature.

"If by the assistance of a high temperature we lower the
weight of an oxide which is at its maximum, and which does
not happen to be volatile, or if by a high continued heat we
elevate a metal to its highest oxidation, are we to believe
that all the ascending or descending terms of oxidation,
which may be inserted between the extremes, are to be taken
as so many different terms of oxidation ? Certainly not. I
do not recognise in that the ordinary course of nature, and I
venture to believe that in similar cases we only make mixtures
in all possible proportions of the oxide at minimum with the
oxide at maximum.

• Journal de Physique. Tom. 50, page aSl- 1802.

HISTORY OF THE ATOMIC THEORY. 221

" 1 will relate a few facts very suitable for rendering this
view plausible, if they do not confirm it. In analyzing, as I
have had occasion to do, some of the oxides of all degrees
which Ilinman has announced in calcining steel, iron, and cast
iron, I have met with only two known oxides of this metal,
mixed in different proportions ; the ores yielded me only an
equal mixture of black and red oxide.

" If we examine the greenish oxides which lead and bismuth
give at the commencement of calcination, and those of tin,
copper, &c., we only find an oxide at the maximum which
envelopes difi*erent portions of the metal. If now we measure
these degrees of oxidation by the nitrous gas which they
give, we shall be led to believe that the metals oxidize them-
selves in all doses. But, no. There are unions of oxygen
like those of sulphur, acids, &c. Election (elective aflfinity)
and proportion are two poles, round which invariably move all
the systems of true combination, whether in nature, or in the
hands of the chemist. In a word, oxygen is not one of those
bodies which can be mixed; when it combines, it subjects
itself to certain proportions, and these proportions are what
we have now to study."

1806. Vol. Ixiii., page 367.

Defending Klaproth, he says, ^' A combination, according
to our principles, Klaproth would tell you, is a sulphuret
of silver, of antimony, of mercury, of copper ; it is also a
metallic oxide ; it is a combustible body acidified ; it is a
privileged production to which nature assigns fixed propor-
tions; it is an existence which nature has never created even
in the hands of man, except with the balance in her hand
pondere et mensura. Know then, he would add, that the
characters of true combination are invariable as the propor-
tion of their elements. From one pole to the other they are
found the same under these two aspects, their physiognomy
only may vary according to their mode of aggregation, but
never their properties. No differences have been observed

222 MEMOIR OF DR. DALTON, AND

between the oxides of iron of the south and those of the
north. The cinnabar of Japan has the same proportions as
that of Almaden. Silver is neither oxidated nor muriated
diflferently in the muriate of Peru from the muriate of Siberia.
In no part of the known world will you see two muriates of
soda, two muriates of ammonia, two saltpetres, two sulphates
of lime or of potash, soda, magnesia, or baryta, which are
different; in fine, it is with one measure that all the com-
binations of the globe have been formed."

Page 370. " Nature has imposed certain laws of proportion
in relation to those unions which we have come to call combi-
nations."

Vol. Ixiii., page 439.

" None of the researches which have been undertaken
hitherto to assist the hypothesis of variable oxidations, even
among the class of nonmetallic combustibles, have been able
to discover above one or two of each ; and each of these
once oxidized is equally a product, the characters of which
are invariable, preserving its properties with firmness on all
occasions where they can be shown, whether free or in a state
of combination. To this height are we now arrived in this
branch of natural science."

Page 466. " There is nothing whatever in opposition to our
extension of the same principles by regarding the solutions of
sulphur, phosphorus, carbon, arsenic, zinc, &c., in hydrogen,
not as simple solutions, without measure, in unfixed propor-
tions, but as proportional combinations, as hydrurets of sul-
phur, phosphorus, &c., which the excess of the solvent may
take into solution."

" Sur les Sulfures Metalliques."

Jour, de Ph., vol. lix., page 261, year 1804.

The following is a portion of the controversy between
Berthollet and Proust. It begins with quotations from
Berthollet.

" He (Proust) believes that there is attached to antimony

HISTORY OF THE ATOMIC THEORY. 223

a dose of sulphur invariably fixed by nature, and that it b
not in the power of man to increase or diminish it. He fixes
this at 25 per cent."

Proust continues, " It is not I, but nature, or whatever
power you choose, which places a barrier between it and all
the efforts of every chemist who will attempt to make sul-
phuret of antimony above or below this proportion. / have
assigned no law to my discovery ; I have verified it only ; 1
have followed the precept which Berthollet himself has traced
in his profound work; when, says he, one substance combines
with another, it is necessary to determine the proportions, and
to examine the properties, &c. Such, in fact, has been the
constant object of chemists, from the moment that they recog-
nised that this determination was one of the most important
bases of the history of combinations and of the science of
analysis. Nobody can believe that nature will abandon her
compounds to the chance of those variable proportions which
Berthollet has chosen as the foundation of his system. But
it is not the less true, that in proportion as the horizon of
sulphurets extends, we do not see that the new facts which
every day accumulates are of a nature to strengthen it."

Berthollet against Proust. " He has combined the oxide
of antimony with different proportions of sulphur, and has
obtained mixtures which may be represented by this formula;
oxide +1+24-3, &c., of the sulphuret of antimony: has he
not obtained there veritable combinations ?" Page 262.

Proust: " To this, I shall reply, that solutions which have
commenced, or which have not attained the term of saturation
of which we consider them capable, ought to be viewed
differently from combinations which are completed; but to
explain myself, I illustrated those solutions in the same way I
would do those of sugar in water, that is, as water + 1 +2+3 of
sugar. I do not see that we can form more distinct ideas of the
solutions of the sulphuret of antimony in its oxide. All chemists
have hitherto believed that these glasses, livers, and crocuses,

224 MEMOIR OF DR. DALTON, AND

were oxides which had been sulphuretted. The object of my
work has been to show the fallacy of this, and that we must
give up these sulphuretted oxides, which we admit, without
proof, and receive in their place a species of combination,
new, without doubt, but well demonstrated. Certainly
this combination is in opposition to the ideas of Berthollet ;
he wishes to place them in the family of sulphuretted oxides,
but it is no less certain, that those which I have announced
do exist, and that they have this advantage over sulphuretted
oxides, the existence of which is now terminated, that they
afford the most natural solution of those thousand and one
problems in antimony, the ridiculous nomenclature of which
has shown the confusion of our ideas, and covered with
obscurity the history of that metal."

Page 264. " To a lib. of potash you add an ounce of arsenic;
it is not saturated, you add two, you add three, it is not yet
saturated, and so with more; but in waiting to discover the
point of saturation, I repeat to them ; your arsenical potashes
are nothing at present but potash, plus one, two, or three of
arsenic, but we have not time to prove that this combination
will obey, as it no doubt will, the law of proportion, and shall
not press you to decide on it. These are results so variable
that they destroy your laws of proportions, and render your
apothegms illusory. Berthollet is too just not to agree that
the series of numbers by which I have sought to represent
the solutions of the sulphuret of antimony in its oxide, has not
the least relation to that which I. have hitherto called pro-
portion in combinations."

Journal de Physique, 1805, vol. lix., page 321.

" Sur les Oxidations Metalliques."

" I ought to explain, says Berthollet, that the proportions
of oxygen may vary progressively after the limit or the com-
bination becomes possible, until it attains the last degree;
and when this does not take place, it is because the conditions

HISTORY OF THE ATOMIC THEORY. 225

which I have indicated become an obstacle to this progres-
sive action."

"A little before this are to be found the facts on which
this illustrious chemist establishes the theory of progressive
oxidations, which he opposes to that which I have given out
on different occasions, and of which the base is, that the com-
bustible bodies are arrested at fixed terms of oxidation, in the
same way as we see to be the case with sulphur, phosphorus,
carbon, azote, and the greater part of the metals."

Page 328. After shewing that the fine lead powder got
by shaking the metal in a bottle is a mixture of metal and
oxide of lead, and not a low and varying degree of oxidation,
he adds ;

" But is each of these molecules, one might say, suddenly
at one leap elevated from 0 to 9, to 12, to 25 per cent ? And is
it possible that they do not pass successively all the ascending
terms which the imagination can conceive possible between
the two extremes ! I reply, that it is impossible in the actual
state of things to say if the oxidation follows or does not
follow this progression, because in the calcination of a metal,
of lead for example, the senses are not struck with any
phenomenon which can guide the judgment in the choice
between two opinions ; but although we do not see intui-
tively that which occurs actually in calcination, we are not
hindered from judging clearly by the aid of numerous analo-
gies which the field of combination offers."

Page 330. ** Let us mix the green sulphate of iron with the
red, each base will hold its own amount of oxygen, and there
will be no conciliation between the two, no division which
will bring forward to us those intermediate oxidations which
the mind would desire to discover. Is it a piece of iron which
we throw into the red sulphate ? We see the base of the salt
descend to 28, not by a retrograde march which arrests each
of these particles at 47, at 46, at 45, &c. of oxidation, but by
the instantaneous lowering of each from the limit (or term),
2 a

226

48 to 28, and this is well confirmed by analysis, because we
discover in the solution nothing but red molecules mixed with
green ones."

Page 334. *' I will say then of the sulphurets as I said of
the oxides, there are only two of them."

Speaking of the oxide of copper :

Page 351. " If we establish the calculation on this basis,
we find that a quintal of yellow oxide is composed of 86 of
copper and 14 of oxygen, whilst the black oxide to which we
wish to compare it, contains only 80 of metal and 20 of
oxygen ; or in other words, if copper condenses 25 per cent,
of oxygen to raise it to its maximum, it condenses only 16.3
to raise it to its minimum. Here then, we find, as in all other
combinations of oxygen, new reasons for recognising this law
of nature, which subjects the metals and combustibles to those
proportions from which we cannot separate them, however
various may be the circumstances under which they have
united."

It really is a melancholy thing to read these papers of
Proust. He had advanced by the most careful steps to the
conclusion, that Jill combinations were made in proportions
defined by some law of nature, that they were weighed and
measured before they were united, and yet failed to see a
law. Richter used the words from the Septuagint, God
has made all things by measure, number, and weight; and
Proust uses a similar phrase with his " pondere et mensura,"
from the Vulgate, leaving out the word number, which he did
not sufficiently see. He saw, with great clearness, that with-
out such constant proportion the products of nature would
lose their stability, and the characters of bodies could not be
depended on for permanence. We have here no difficulty in
judging how much he did, and how much he left undone ; how
far his own mind was advanced, and how it had merely specu-
lated. He tells us all distinctly. When he uses +1+2+3 of
proportions, he tells us it is merely for illustration, he did not

HISTORY OF THE ATOMIC THEORY. 227

mean it to indicate the order of combination, he had in fact
made no theory, at least found no law on the subject, although
he clearly saw that it must be owing to some law of nature.
He fought for constant proportions in combinations, and
fought well, but he had no idea of a constant quantity of
oxygen found uniting with a constant quantity of every metal,
and making higher oxides by steps always of an equal alti-
tude, although he proved that the rise was not that of an
inclined plane, but by " fixed terms," And yet it follows as
a consequence, so closely in fact does it follow, that we must
put ourselves in the position of the early chemists of the
century well to understand the difference. When we have
taken that position, we then see how thin was the veil,
although utterly impenetrable, that divided his opinion from
the present, and prevented the acute, active, and logical mind
of Proust from attaining to the great discovery. His deter-
minate proportions are given as remarkable facts, in connec-
tion with which he confessed to perceive no law.

Had such men studied Higgins, we should probably never
have heard of this controversy, but he was not studied. We
may therefore learn not so readily to blame a man for want
of honesty, when he publishes for a discovery what has been
known before. The most indefatigable workers of the period
had neither read Higgins nor Richter. Besides, scientific
men like other men are led by fashion, the follies of some
men become great discoveries for a while, and the wisdom of
men comparatively obscure, such as the two mentioned, is
neglected or sneered at. Yet the whole body endeavours to
acknowledge facts only.

As a specimen of the chemical books of the time, let us take
one published in the same year as Dalton*s work on the atomic
theory, although after Dr. Thomson had made it public, " A
Course of Theoretical Chemistry, by Friedrich Stromeyer."*

• Grundriiit Theoretischer Cbemie zum bchuf Seiner Vorlesungen entworfen
von D. Friedrich Stromeyer. Gottingen, 1808.

228 MEMOIR OF DR. DALTON, AND

He says, p. 66, § 36, " The affinity of a substance towards
another is always in proportion to its chemical mass, which it
brings with it for combination."

Page 68. " Affinity is consequently in no way an elective
attraction, in the sense in which Bergman and his followers
have taught it."

Page 80, § 59. " By means of affinity alone two substances
may combine with each other in every quantitative proportion.
Although this asserts quite the opposite of Bergman's theory,
and even appears to contradict experience, it is nevertheless a
perfectly natural consequence of the above.

" For suppose A and B could combine in the proportions
of 5 : 7, and not as 10 : 7, if we put 7 parts of B with 10 of
A, then the very same thing would happen as when we put 7
parts of B with 5 of A ; that is, the 7 parts of B would com-
bine with 5 parts of A, and the other 5 parts would remain
uncombined.

" If this were really possible, then it would follow clearly
that 10 parts of A contained no more affinity than 5 parts,
which however completely contradicts what is proved in § 36."

The idea of the present law seems to have entered into his
mind as a conclusion to be avoided for its absurdity.

§ 60. " But as soon as the power of cohesion or expansion
of two substances of a given mass, acting on each other,
ceases to be overpowered by their affinity, an exception con-
stantly takes place to this universal law, and a certain propor-
tion of mixture is established between the two substances,
which, on account of their affinity, can no longer be surpassed,
and consequently limits their mutual affinity.

" But if there were a removal of the obstructions caused
by cohesion and expansion to the affinity of two bodies, then
the law would again come into action in its first unity."

" The absorption of several gases by water, the solution of
salt in water, and the oxidation of metals, best establish that
which has been said."

UISTORY OF THE ATOMIC THEORY. 229

§ 61. " This general law is subject to an exception also,
when there is a change of the aggregate condition during the
action of two or more substances, and in this case also a com-
bination takes place of a fixed proportion."

Here we have a clear account of the direction that Ber-
thoUet's teachings gave, and the consequences are logically
deduced. Here, too, we find that fixed proportions are
obtained as exceptions, but it is also seen how needful it was
to have them occasionally in order to explain facts in the
science.

Stromeyer's words do, in fact, represent the confused and
contradictory opinions of the time, and afford us another proof
that no one before Dalton had given opinions sufficiently
authoritative on the atomic theory to be retained by the
teachers of chemistry ; and we may add also, none deemed
of sufficient importance to demand at the time very serious
discussion.

This want of attention, even to imperfect theories, arose
mainly, I believe, from the fact, that those theories hitherto
given had not had accumulative scientific proof to give them
force in the world ; they had organized no executive force.
Chemists, generally, had not arrived as far as the inquiries
already quoted.

It was intended to give a number of similar instances, to
show how entirely all atomic theories and theories of definite
proportions were out of the boundaries of general chemical
science when Dalton published. I happened to take up
Stromeyer first; many instances occur in our own country,
but this will probably be found sufficient.

230 MEMOIK OF DE. DALTON, AND

CHAPTER XI.

DALTON S ATOMIC THEORY.

We now come to Dalton, whom we have left since he first
thought of weighing atoms ; this has been done in order that
by accumulating all the materials he might have used, we
may know what has been his especial work. Matters stood
thus : Higgins had, in 1789, seen the fundamental principle
clearly, and given it out more as a thinker than a discoverer,
neglecting to generalize; that principle included simple
proportion or the law of necessary definite composition
and multiple proportion. Richter had systematized all the
laws of combination known to him, but had not known of
Higgins, although he would there have got the clue to all
his strivings. He discovered one of the most important con-
sequences of the fundamental law, in reciprocal proportion,
but did not rise up to first principles. Scientific men could
get no decided guide from either, and preferred to follow
BerthoUet, who was leading them out of the right direction,
obstructing for many years the advance of chemical philoso-
phy, or compelling others to accumulate proof until it was
suflScient to overwhelm him.

The materials we have for tracing the progress of Dalton's
opinions are few, but distinct and sufficient. I shall not enter
into the argument of honesty, which can be thrown with greater
violence at so many heads, but shall take it for granted, that
all those who have had the honour of working at the laws of
chemical combination with any success, have also had the
advantage of an honest mind. I know of no dishonesty on
any side among the principals connected with this subject, and
their defenders have erred, probably, on account of proving
one side better in morals than the other.

HISTORY OF THE ATOMIC THEORY. 231

From the earliest period of his scientific life Dalton had
been accustomed to think carefully on the constitution of the
atmosphere ; this is seen as early as 1 793, in his meteorology.
This subject continued to be a favourite one, and led him to
gases generally. The experiments quoted at p. 43, on nitrous
gas and oxygen, and those mentioned afterwards in a quota-
tion from Dr. Thomson, shew the method by which he came
to believe, and to prove experimentally, the existence of
definite and constant proportion.

Here lies the difference between him and Higgins. Higgins
expressed the fundamental idea as clearly as Dalton, but it
was still left uncertain. Dalton proves it by experiment,
draws the conclusion, and tells us the "theory" in a few
lines. We have then distinctly the method by which he
came to believe in definite proportion and multiple propor-
tion. He proved them for himself, and theorized for himself.
No books of any writers before him, no Proust or Berthollet
controversies were so decisive as these few experiments of
Dalton ; not clearer than the words of Higgins, but more
decisive, because the result of observation and of i;^asoning
combined. This seems to have been his first direct Entrance
into the region of the atomic theory.

In reading over his earlier works, or even in reading the
short account here given, we may remark with what a firm
grasp he lays hold of the existence of atoms, of the idea that
all matter is made up of separate ultimate particles, divisible
or indivisible. We find no scientific man holding the idea
with such firmness; to others it was a theory, to Dalton it was
a fact, which he could not conceive otherwise. We find that
even the air is represented* as an agglomeration of bodies
heaped up like piles of shot. We appear to be entirely
removed from the region of speculation when reading his
words; although he leads us farther than the most fantastic
speculator had done, the road is made so clear before us, that

* Page 17.

232 MEMOIR OF DE. DALTON, AND

we find no difficulty, either physical or metaphysical. He
persuades us to go, leads us and describes all to us in a few
sentences, when volumes of persuasion written before had not
been sufficient to induce men to turn their eyes. His descrip-
tions are rigid as well as picturesque. Some persons would
apply to them the word material, and still more the word
mechanical. It was by following rigidly the mechanical pro-
perties of his atoms that he arrived at his results. To those
who read his works, it will be clear that his mind became
gradually more confirmed in this course.

In reading what he says, at p. 49, we see him plainly verging
towards his theory, and also the nature of his struggle, which
is in no respect similar to that of any other inquirer. He there
first says, that he is inquiring into the relative weights of the
ultimate particles of bodies. This idea had never suggested
itself as practical to any one before Dalton, nor am I aware
that it has ever been claimed. Having made some advance
in this inquiry, he made it the starting point of all that he
advanced on atomic chemistry and the theory of proportion.

He was not in haste to publish his theory, but told it openly
to Dr. Thomson, in 1804; this, then, is the date of the com-
plete discovery, as Dr. Thomson published an abstract of
it at once. Some persons unacquainted with this have advanced
an argument against him, his own book containing the sub-
ject not having been published till 1808. A well known
quotation from Dr. Thomson's history says, " Mr. Dalton
informed me that the atomic theory first occurred to him
during his investigations of olefiant gas and carburetted
hydrogen gas, at that time imperfectly understood, and the
constitution of which was first fully developed by Mr. Dalton
himself. It was obvious from the experiments which he made
upon them, that the constituents of both were carbon and
hydrogen, and nothing else. He found, further, that if we
reckon the carbon in each the same, then carburetted hydrogen
contains exactly twice as much hydrogen as olefiant gas does.

HI8T0BY OF THE ATOMIC THEOEY. 233

This determined him to state the ratios of these constituents
in numbers, and to consider the olefiant gas a compound of
one atom of carbon and one atom of hydrogen ; and car-
buretted hydrogen of one atom of carbon and two atoms of
hydrogen. The idea thus conceived was applied to carbonic
oxide, water, ammonia, &c., and numbers were given represent-
ing the atomic weights of oxygen, azote, &c., deduced from the
best analytical experiments which chemistry then possessed."

His first atomic weights, already given,* were published in
1803 ; he did not publish his " New System" till 1808. He
says then, t " A pure elastic fluid is one, the constituent parti-
cles of which are all alike, or in no way distinguishable.
* * * These fluids are constituted of particles possessing
very diffuse atmospheres of heat, the capacity or bulk of the
atmosphere being often one or two thousand times that of the
particle in a liquid or solid form. Whatever, therefore, may
be the shape or figure of the solid atom abstractedly, when
surrounded by such an atom it must be globular ; but as all
the globules in any small given volume are subject to the
same pressure, they must be equal in bulk, and will, therefore,
be arranged in horizontal strata like a pile of shot.'*

The chapter " On Chemical Synthesis" gives his theory.
He there says, " When any body exists in the elastic state, its
ultimate particles are separated from each other to a much
greater distance than in any other state ; each particle occu-
pies the centre of a comparatively large sphere, and supports
its dignity by keeping all the rest, which, by their gravity, or
otherwise, are disposed to encroach on it, at a respectful dis-
tance. When we attempt to conceive the number of particles
in an atmosphere, it is somewhat like attempting 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

• Page 49. f *' A Now System of Chemical Philosophy." Part I., p. 145.
2H

234 MEMOIR OF DR. DALTON, AND

as in a given space of the universe, the number of stars and
planets cannot be infinite."

" Chemical analysis and synthesis go no farther than to the
separation of particles one from another, and to their reunion.
No new creation or destruction of matter is within the 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 state 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 ascertain the relative weights of the
simples which constitute a compound. But unfortunately
the inquiry has terminated here ; whereas from the relative
weights in the mass, the relative weights of the ultimate
particles or atoms of the bodies might have been inferred,
from which their number and weight in various other com-
pounds would appear, in order to assist and to guide future
investigations and to correct their results. Now it is one
great object of this work to shew the importance and advan-
tage of ascertaining the relative weights of the ultimate
particles^ both of simple and compound bodies, the number of
simple elementary particles which constitute one compound
particle, and the number of less compound particles which
enter into the formation of one more compound particle,

" If there are two bodies A and B which are disposed to
combine, the following is the order in which the combinations
may take place, beginning with the most simple : namely,

1 atom of A-|-l atom of B=l atom of C, binary.

1 atom of A-\-2 atoms of B=:l atom of D, ternary.

2 atoms of A-j-l atom of B=l atom of E, ternary.

1 atom of A-f 3 atoms of B=:l atom of F, quaternary.

3 atoms of A-f 1 atom of B=l atom of G, quaternary.

&c., &c.

HISTOBY OF THE ATOMIC THEOliY. 235

" The following general rules may be adopted as guides in
all our investigations respecting chemical synthesis.

'^ Ist. 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.

" 2nd. When two combinations are observed, they must be
presumed to be a binary and ternary.

"3rd. 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 specifically 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."

• ♦♦»♦*»

" 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 principal acids, the
alkalis, the earths, the metals, the metallic oxides and
sulphurets, the long train 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 original experiments.

" From the novelty as well as importance of the ideas
suggested in this 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 by a small

236 MEMOIR OF DR. DALTON, AND

circle, with some distinctive mark; and the combinations
consist in the juxtaposition of two or more of these; when
three or more particles of elastic fluids are combined together
in one, it is to be supposed that the particles of the same kind
repel each other, and therefore take their stations accordingly."

In the figures to which he refers above he has shewn
to us how vividly he formed these ideas, that they ^ere^
no mere fancies which had passed through his brain, but
distinct impressions, ready prepared for utterance. No doubt
is left upon our minds as to his opinions, which are, that
every piece of matter, even the smallest, must follow the
laws of the largest ; that when pounds of matter unite, the
atoms contained in them must unite also, until we come to
the fact that only atoms can really be said to unite. Now as
the conception of any fraction of an atom is a contradiction
and impossible, they must constantly unite as wholes, and the
proportion will be constant. If constant in the smallest
quantities, then so in the largest, explaining the permanency
of the constitution of bodies so much disputed, and making it
a law of nature. If two compound bodies unite, the same
law is followed out.

He then gives instances of combination, and adds to his
explanation a plate of the " arbitrary marks or signs chosen to
represent the several chemical elements or ultimate particles."

He gives twenty atomic weights and seventeen analyses of
gases and acids. His atomic weights are —

Hydrogen, its rel. weight. . 1

Azote 5

Carbone 5

Oxygen 7

Phosphorus 9

Sulphur 13

Magnesia 20

Lime 23

Soda 28

Potash 42

Strontites 46

Barytas 68

Iron 38

Zinc 56

Copper 56

Lead 95

Silver 100

Platina 100

Gold 140

Mercury 167

HISTORY OF THE ATOMIC THEORY. 237

** An atom of water or steam composed of one oxygen and
one hydrogen, &c. = 8," and so on with other bodies.

This is the result of enormous labour, added to that of the
many gaseous analyses. Let no one say that because the atomic
weights are in most cases inexact he shews want of power.
We have seen in our own days how difficult it is to get an
exact atomic weight, we have found that it needs the com-
bined forces of several laboratories to settle one to satisfaction,
and we must rather admire that man who approached first so
near. But, although Dalton has been called a rough worker,
and I am not prepared to deny it, we must remember that his
analyses are not behind the time, but in advance of it in early
life. At the period when he was working out this theory, the
analyses of all chemists were in general only approximative.
Fine analysis was only then beginning its course. But as
Dalton says, "it is not necessary to insist on 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."*

He also says, "it is not to be understood that all those
articles marked as simple substances, are necessarily such by
the theory ;" ex, gr,y soda and potash are mentioned as com-
pound.

In various parts of his work we learn exactly the method
in which he applied his theory, and as he devoted his time
to its illustration, we are not left in any doubts as to his
opinions.

We have now to find exactly what new ideas he produced.
We have seen in the last chapter the state of chemical
opinion, the prevalence of the Berthollet philosophy, and the
uncertainty hanging over the opinions opposed to his.
General opinion on combination was in reality not more
advanced than in the earliest days of the science. Dalton
found matters in this state of confusion, and we have seen the

• Page 220.

238 MEMOIR OF DR. DALTON, AND

results he arrived at, and the process. 1st. By long reflection
on the constitution of bodies, especially of gases, he became
convinced of the necessity for ultimate particles, divisible or
not so. These particles unite together, and form of course a
definite compound. If the smallest part is definite, so is the
largest. This is the fundamental law of definite compounds.
2nd. Various numbers of atoms may unite — there may be
one, two, three, or more — there can be no division of atoms.
As large bulks are constituted just as small are, so multiple
proportion becomes a law by which bodies are constituted.
3rd. Compound bodies constituted as the above unite par-
ticle to particle in a manner exactly similar to simple
bodies, and so we have compound proportion, and are led to
a mode of inquiry into, and a method of expressing the most
complicated bodies. 4 th. If we obtain the relative weights of
the constituents of bodies we obtain the relative weights of the
atoms, because the smallest parts must be constituted as the
largest. 5th. The relative weights of the atoms become con-
stant expressions for the proportions of combinations.

These are the fundamental principles which made chemistry
a science and hold it together, and although Dalton had no
direct help in discovering any of them, we have seen that
Higgins had already expressed the first two. Richter and
Fischer had made out numbers representing the reciprocal
proportion of bodies, and although not going to first princi-
ples, and establishing no law, Fischer's numbers adopted by
Richter, I believe in 1803, are really atomic weights or
equivalents, although they did not see them to be such.

There existed, therefore, in the world material for com-
pleting the theory of combination, but there was no one who
saw it clearly, and no one who knew both parts published.
Dalton cannot be blamed for not knowing them ; no one knew
them. Although Dalton had to begin without their aid, the
custom of the world is to give credit to him who adds to its
accumulated knowledge, not to him who obtains knowledge in

HISTORY OF THE ATOMIC THEORY. 239

his closet merely. By this custom, therefore, Dalton's credit
would be the whole theory, minus what Higgins and Richter
had done ; how much this was who will venture to declare,
the two parts being the conceptions of different brains, so that
Thomson, with his great quickness, could make nothing out
of one, and Berzelius, with his patience, nothing out of the
other ; nevertheless, Dalton must not have their credit, and it
was not the habit of his independent spirit to seek from others.
Dr. Henry has made it clear that he had not seen Higgins's book.
He no doubt saw Proust's results. They are in the library of
the Manchester Society, and they are probably the most likely
to have assisted him, as the analyses and reasoning are re-
markably clear, but devoid, as before said, of theory; still
the clearest and best were later than Dalton. This, there-
fore, seems to be the result, that although actually producing
all the theory within himself, from the world his deserts are
that he first saw the great importance of the idea of using
atoms to illustrate proportion and definite constitution. He
followed up the idea, and found in it a fundamental natural
law, as it appears hitherto. He saw the use and importance
of multiple proportion, or the adding of atom by atom in
twos or in threes, and he proceeded to investigate nature
under this impression. He proved that bodies followed laws,
such as fitted his hypothesis, which was thenceforth taken
into the province of scientific theory. To perform the above
it was needful to grasp the idea more firmly than it had
been done, to work laboriously, and to decide convincingly.
This Dalton did. He then extended this from simple to
complex combinations, and gave the first idea as well as proof
of compound proportion, laid down the laws orderly into a
system, and accompanied the whole by abundant and laborious
proofs. He gave the first idea of atomic weights. Under
this head came Richter and Fischer's numbers. Richter
grappling with those numbers never could obtain a rational
theory from the phenomena. Dalton's plan explains these

240 MEMOIR OF DR. DALTON, AND

numbers with the greatest ease, and looks on such as a
necessity of the fundamental law, instead of the beginning
of the inquiry as it was to them.

It seems to me, then, that what happened historically,
happened also intellectually. Dal ton had included his pre-
decessors in his more extensive system. He had gone to the
summit of the hill, and when coming down, found proofs that
they had been making good progress upwards. Higgins had
gone at once to the top, as it appears to me, but took no heed
to make the needful observations when he was up, or he
found the prospect entirely obscured. We are compelled to
put reciprocal proportion in a secondary position, as it seems
to me it cannot be called a law, but one of the consequences
of a law ; and the evidence brought to support it, otherwise
than empirically, presupposes some of the principles on which
the general laws depend.

It was by a careful mechanical juxta-position of parts that
Dalton arrived at his idea, it is eminently mechanical, and it
is remarkable that all progressive views on that subject have
been so. He introduced proportional weight into the theory,
and found it to agree with facts. His is, therefore, the
quantitative atomic theory. In this complete form no one
seeks to take from him the honour. The total is so entirely
his, that the disputed parts can be held only as a fealty.*

Although Dalton rigidly held to the idea of atoms, he by
no means supposed that we had attained the indivisible atom

* Dr. Schweigger, in his pamphlet, objects that Dalton's theory was not
conceived in the spirit of the ancient theory, because he allowed some atoms
to be small and some large. Strange this. The reason that the ancient theory
is insufficient, is simply because it was not conceived in the spirit of Dalton's.
2nd. Most of the ancients allowed greater and smaller atoms, and various shapes.
3rd. Dalton formed his theory in the belief that atoms were of one size, but
afterwards saw reason to change his opinion. Dr. Schweigger, therefore, has
forgotten the opinion of Dalton and the ancients, as well as Richter's preface,
where he calls the permanent neutrality of neutral salts after neutral decompo-
sition, a well known fact. He sneers at the atomic theory, thinking that by
putting it down, Dalton will fall ; I don't agree with him there, but there is
time enough to wait.

HISTORY OF THE ATOMIC THEORY. 24 1

in our elements; at least, he expressly reserved this point.
What he speaks of is simply the ultimate particle that seems
to act in our chemical processes.

Dalton used atom and particle. Many have objected to
both, but they are words which really involve less theory, and
are more generally applicable than any yet obtedned, except,
perhaps, combining proportion, which is too long. Equivalent,
Wollaston's word, is itself too long, limited in its meaning at
best, and at times either meaningless or incorrect. Whenever
we conceive of combining proportion, we reduce the quantity
to the smallest conceivable, every portion becomes a unit,
and each unit is undivided ; it is a particle for the moment,
and an atom as far as the effect we study is concerned.
Having, after much labour, attained this mode of thinking,
we can now scarcely think of compounds otherwise, nor
indeed has any other method suggested itself as better, al-
though investigation is promising advance in our knowledge,
and will probably some day astound us by its results.

The consequences of Dalton's laws gradually shewed them-
selves to be, that there was now one great law or theory in
chemistry, so that it was for the first time fit to be called a
science. Heretofore it was a series of separate facts, and even
now we may say that it is more a branch of natural history
than of exact science, but as a science it is preserved by this fun-
damental law and its branches, and by this only. It is stretch-
ing itself out in many directions, and its future will undoubt-
edly be still more brilliant ; at present, although it has planted
its standard in numerous spots, it has fixed a government on
few, but still issues the central law unchanged, although with
explanatory extensions. The history of the atomic theory,
since Dalton's time, is contained in Dr. Daubeny's work, and
on that it is not my desire to encroach, nor could 1 hope to
equal it.

A very little need be said as to the consequences of the
promulgation of Dalton's views. They were explained in
2 I

242 MEMOIR OF DR. D ALTON, AND

1804 to Dr. Thomas Thomson, the very learned professor of
chemistry in the University of Glasgow, and by him they
were inserted in his system of chemistry. But it was not a
truth that could electrify the world, it was on a subject on
which few thought, one of which many said, '' what is the
use of it?" that miserable question which occurs to men to
whom the revelation of God's truth is of no interest, unless
an immediate advantage is promised. Dr. Thomson (Nichol-
son's Journal, Vol. 21, p. 87) says even four years after,
" This curious theory, which promises to throw an unex-
pected light on the obscurest parts of chemistry, belongs to
Mr. Dalton;" shewing that even then it required to be
taught even to chemists. We find in reality that for years
afterwards it was to most chemists a mere speculation.

In a paper by Wollaston in the same volume, p. 164, he
says, " Dr. Thomson has remarked that oxalic acid unites to
strontian as well as to potash in two different proportions, and
that the quantity of acid combined with each of these bases
in their superoxalates is just double of that which is saturated
by the same quantity of base in their neutral compounds.
As I had observed the same law to prevail in various other
instances of superacid and subacid salts, I thought it not
unlikely that this law might obtain generally in such com-
pounds, and it was my design to have pursued the subject
with the hope of discovering the cause, to which so regular a
relation might be ascribed.

" But since the publication of Mr. Dalton's theory of
chemical combination, as explained and illustrated by Dr.
Thomson, the inquiry which I had designed appears to be
superfluous, as all the facts that I had observed are but
particular instances of the more general observations of Mr.
Dalton, that in all cases the simple elements of bodies are
disposed to unite atom to atom singly, or if either is in
excess, it exceeds by a ratio to be expressed by some simple
multiple of the number of its atoms."

HISTOEY OF THE ATOMIC THEORY. 243

It is plain that Wollaston, who was behind in no theories,
was unable to obtain from the knowledge of the times an
explanation of these phenomena, even when he saw the
difficulty clearly ; and it is plain also, that although it was
said that he would have discovered it had Dalton failed, that
he did not discover it even when he had in his hands as
many facts as Dalton had, and a greater power of accurate
workmanship. The genius was wanting, the acuteness of
Wollaston and of Proust could not penetrate, where the sim-
plicity of Dalton was at home.

In Sir Humphrey Davy's Bakerian lecture for 1809, in
giving some analyses, he says, " the same proportions would
follow from an application of Mr. Dalton's ingenious suppo-
sition," but even he, with a mind much more capable, as we
might suppose, of delighting in grand general laws, such as from
their brilliancy come upon us like the finest poetry, even then
saw little in the new theory, and said little upon it. When it
began to be established he was inclined to prove that Dalton
was not the first discoverer, although when he delivered his
discourse on giving Dalton the gold medal of the Royal Society
he had arrived at a clearer view of the subject. The same
slow vision was, as might be more readily conceived, the case
with Berzelius, who took it gradually up as it came from his
own analyses, growing during his whole life into more and
more absolute certainty. But Dalton had given a table of
atomic weights in 1803, and for years these philosophers
plodded after him with numberless proofs, Berzelius surpassing
all others in accumulating and arranging scientific wealth.

It will not be pleasant to review the delinquencies of our
great men, nor the slowness of their conceptions, their desire
to limit the law, and to cramp it down to the bounds of their
own knowledge, denying its power to explain more than they
had seen. Scepticism has its work to do in the world, and
credulity has had many victims, but it may well be said that
the amount of knowledge to be gained is so great that our

244 MEMOIR OF DR. DALTON, AND

capacities for belief must enlarge themselves rather than
diminish, and we shall be left behind with a small and inade-
quate supply of intellectual food, if we refuse to take it until
we have extracted its one-tenth per cent, of questionable
adulteration.

The law has established itself; it is true. Our knowledge
of its ramifications will increase. If it had not great rami-
fications, we might question its own intrinsic greatness.
Isomorphism and isomerism are two of these, beautiful in every
respect, thoroughly beautiful. But they are no contradictions,
the number of provinces do not prove the smallness but the
greatness of a kingdom. Why then should they even be
mentioned as modifications, they may be said even to be
necessary results. Allotropy is itself a curious and beautiful
fact, and one that we may readily suppose will widen
itself out, perhaps even till alchemy itself shall cease to
be wonderful ; but it does not disprove the atomic com-
binations.

We may call the ultimate particles which practically unite
equivalents, as Wollaston did, but we don't alter the fact, we
only chronicle our hesitation, and substitute a name which
cannot be final, as it represents only a temporary theory ; it
only says that the quantities are equivalent to each other, but
refuses to decide what these quantities are. We may call
them volumes, like Berzelius, but we find then that we go on
a wrong hypothesis, as the atomic volumes are not the same
as their weights in every condition, whatever might be the
case if all were gaseous.

We have, in fact, found no name representing the case as
well as atom, and, giving due limits to the meaning of the
word, it represents the state of belief in the mind of every
chemist, whilst no fact whatever bears directly against it.

At the same time I do not mean to advocate the atom with
the physical constitution given to it by Dalton, as well as by
Newton and the ancients, not being able to see it possible ;

HISTOEY OF THE ATOMIC THEORY. 245

but this is not a place for my own views : I have referred to
what may be called the practical atom, or the smallest amount
that unites.

Is then chemistry scientifically disposed of by this theory ?
as well might we say that Newton exhausted the heavens of
its knowledge. Year after year will furnish us with marvel-
lous truths, nor can we believe that centuries or millenaries
will exhaust God*s wisdom in the earth. Already has Davy's
aluminum, a brittle useless powder not quite pure, turned a
beautiful metal, and the slippery mud of a clayey soil been assi-
milated to " shining silver." The atomic theory may be further
analyzed, and under its simple laws may be found another
which will not only include all we now have, but a host of
others still unsuspected ; the time may even come when a new
chemistry will be revealed to us, a world under our present
elements, when every element will be convulsed and shaken
into fragments, by powers which nature will put into our hands;
but even that does not destroy the laws of the present. Even
when that scientific convulsion comes, we can scarcely doubt
that the elements will break up, well proportioned and accord-
ing to regular laws, if they break into fragments at all. But
this stratum of our knowledge cannot be annihilated by any
under stratum ; what we have found is true, whatever higher
truths may overpower us with their splendour. When these
truths come let us receive them openly and willingly, giving
them encouragement instead of envious repulsion, knowing, in
fact, that they must come, and rather let us make an occasional
mistake in harbouring a mere mortal, than lose the opportunity
of an angel for a guest. There are incredulous fools who have
made the world's throbbing heart a blank to them, lest they
should perhance at times be cheated. There have been mad-
men who have refused to eat, lest they should be poisoned.

These reflections naturally arise on considering the manner
in which Dal ton's discovery was reviewed. It cannot be
denied, however, that the time being nearly ripe was the

246 MEMOIR OF Dli. DALTON, AND

cause of its ultimate success. To discover out of place and
out of time is a great misfortune. To be before the age in
knowledge is to a man a curse, and to a generation no ad-
vantage ; at least it would seem so, although there may be a
value even for this occasional misplacement not to be lost
sight of in estimating man's progress towards a higher civil-
ization. But in such cases the individual is not appreciated,
the generation does not hear him, his years pass by in misery,
and his attempts to teach are a failure. That knowledge is
best rewarded which is a fit evolution of the age, and which
can be at once put to use for practical purposes, or for mental
cultivation. It behoves us then to be respectful towards new
opinions, and tender towards crotchets, lest we may be laugh-
ing, as so many have done before us, at beautiful truths.
The rudiments of truth are no more beautiful to us than the
roots of flowers, until we study them thoroughly; by for-
getting this men are made victims who ought to be revered.

HISTORY OF THE ATOMIC THBORY. 247

CHAPTER XII,

LATER LIFE OF DALTON.

Although the atomic theory must ever be considered as
Dalton's great discovery, we find that he obtained it at the end
of a series of investigations of themselves sufficient to have
made him a conspicuous character. These earlier labours
had great influence in advancing physical knowledge, and
first brought him into repute. We find him so early as
1804 lecturing in the Royal Institution, when his theory
was scarcely known but to himself, and when it was not
expected to form part of a lecture. Fame was now beginning
to hover round him, and he was not insensible of the change.
But to persons of his habits, fame is less welcome in person than
by letter, as we may say. They are less fitted for receiving the
compliments of the world addressed to them in their presence,
than for receiving those more impressive results, — great respect
and deference; and, above all, the pleasure of seeing the influence
they exercise upon society. Dalton was evidently conscious
of the position to which he was entitled in the scientific
world, although equally conscious that he was out of place
in those brilliant assemblies in which scientific men in capitals
occasionally mingle. He seems to write as if it were rather
curious, although true, that he, too, was one of them, that
the hope and struggle of his life to attain a position in
science had been realized, but to feel at the same time that
his life was not there, but as before, in his laboratory.

It not unfrequently happened, after this period, that he
was engaged in controversy ; and we find him there acting
with great ease and deliberation, always without fear. Like
most scientific men, he was destined to modify or to contradict

248 MEMOIR OF DR. D ALTON, AND

some of his earlier conclusions, having found that he formed
laws too hastily. At page 9 of his " New System," he
says, " Sometime ago it occurred to me as probable, that
water and mercury, notwithstanding their apparent diversity,
actually expand by the same law, and that the quantity of
expansion is as the square of the temperature from their
respective freezing points. Water very nearly accords with
this law according to the present scale of temperature, and
the little deviation observable is exactly of the sort that ought
to exist, from the known error of the equal division of the
mercurial scale. By prosecuting this inquiry, I found that
the mercurial and water scales divided according to the
principles 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."

In Vol. II.* he says, " The great deviation of the scales
between the temperatures of freezing water and freezing
mercury is sufficient to show, as Dulong and Petit have
observed, that their coincidence is only partial :" and so
acknowledges his error.

In the first volume f he also said, that "the force of steam
from pure liquids, as water, ether, &c., constitutes a geome-
trical progression to increments of temperature in arithmetical
progression." Also, "that the expansion of permanent elastic
fluids is in geometrical progression to equal increments of
temperature." Again,J "that the force of steam in contact
with water, increases accurately in geometrical progression to
equal increments of temperature, provided these increments
are measured by a thermometer of water or mercury." This
seemed an ingenious group of laws, and although he gave
them up, yielding to the results of Dulong, he published
them unaltered in the edition or reprint of 1642. But that

• Page 289. f Page 13. J Page 11.

HISTORY OF THE ATOMIC THEOfiY. 249

was his custom, even when his opinion changed; it was more
with a view of obtaining copies of his own works, than with
the view of continuing any law proved to be incorrect, as
appears from the preface to his Meteorology.

In his " New System," Part Ist, he treats of heat and the
constitution of bodies ; in Part 2nd, which was published in
1810, he treats of the chemical elements. In these volumes
it is remarkable how thoroughly every idea has been revolved
in his own mind, and become his own, before he has ventured
to write it. Every chapter shows a strict independent thought,
but, on the other hand, the book is wanting in the results of
others, and could never consequently be a complete system.
He endeavours to construct the whole science himself, more
than could be accomplished by any man. The book is written
in a more attractive manner than systems of chemistry now
assume ; and there is a constant discussion of questions which
give an insight into the state of knowledge of the time and
the tendency of chemistry. Still ^e arrangement was not
well adapted for the young student, although the work was
a great fund of thought for the advanced man of science.
Even now few will be able to read it without advantage.

Part 2nd is principally taken up in determining the com-
position of bodies and their atomic weights. In the appendix
he enters into discussion with Gay Lussac. He there says.
Gay Lussac's "opinion is founded upon a hypothesis that all
elastic fluids combine in equal measures, or in measures that
have some simple relation one to another, as 1 to 2, 1 to 3,
2 to 3, &c. ; in fact, his notion of measures is analogous to
mine of atoms; and if it could be proved that all elastic
fluids have the same number of atoms in the same volume,
or numbers that are as 1, 2, 3, &c., the two hypotheses would
be the same, except that mine is universal, and his applies
only to elastic fluids. Gay Lussac could not see that a
similar hypothesis had been entertained by me and abandoned
as untenable." In this he refers to the following in p. 188 of
2K

250 MEMOIR OF DR. DALTON, ANU

Part 1st. "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." But he
arrived at the conclusion, "That every species of pure elastic
fluid has the particles globular, and all of a size ; but that no
two species agree in the size of their particles, the pressure
and temperature being the same." Then he concludes, in
Part 2nd, "The truth is, I believe, that gases do not unitg
in equal or exact measures in any one instance ; when they
appear to do so, it is owing to the inaccuracy of our experi-
ments. In no case, perhaps, is there a nearer approach to
mathematical exactness, than in that of 1 measure of oxygen
to 2 of hydrogen ; but here the most exact experiments I
have ever made, gave 1.97 hydrogen to 1 oxygen."

This discussion brings out prominently some of the points
of Dalton's character. }f.e objected to the idea of bulk being
taken as a combining proportion ; it was his great object to
show the importance of weight and the completeness with
which it answered every purpose. He conceived the combi-
nation by bulk as accidental, evidently because he had not
examined the relations of the subject with sufiicient care, and
probably with some aversion, as his own discovery seemed
in question. He is strict in the examination of the analyses
of others, and seeks mathematical precision, when he could so
very easily, in his own researches, overleap a few per cent. Yet
no one would have been, on theoretical grounds, so likely to
arrive at Gay Lussac's law as Dalton himself, as he paid most
attention to the bulk of atoms, giving the relative diameters
of particles of the different gases after giving the relative
specific and atomic gravity. He did not always obtain an
analysis so correct as that mentioned above, he continually,
and to the last, insisted on the atomic weight of oxygen
being 7; and he gives the specific gravity as 14 times that

HISTORY OF THE ATOMIC THEORY. 25 1

of hydrogen, and as he gave the specific gravity of oxygen at
1.127, he was compelled to raise very high that of hydrogen,
which he made .0805. We should have supposed Dalton to
be, of all men, the most fitted for seeing exactly the position
which Gay Lussac's law would take, and for extending our
view of it; but it was not so. His mind had probably be-
come too much engrossed with his own views of the case;
and the belief that the whole subject had been attained, came
in at last to shorten his vision. It is not in science only that
men show that they are not the best fitted for seeing their
own position, and without this knowledge a false step is not
easily prevented.

His memoirs, after this period, were generally on less
important subjects. We see in them the same quality of
originality, the same inclination to strike at the root of a
subject, but it is done with less power ; the result is rather
an idea which he leaves to be worked out. Some of them
are hurried, some are careless, some are unfinished. Had it
lain within the scope of this memoir, I might have shown
many sentences full of latent beauty, which have since budded
and blossomed.

Of these the following is not the least remarkable, although
it had gone farther than a mere idea;^ it was long put into prac-
tice by him. As far as 1 know, therefore, he is to be considered
as the originator of analysis by volume, which has long been
practised to a great extent in the manufactories of Lancashire.
In this respect chemists are still behind Dalton, and have not
yet got into the habit of using all those advantages which his
works have offered, although the actual knowledge on the sub-
ject has advanced far beyond the period of Dalton*s latest years.

In one of these memoirs on the analysis of spring and
mineral waters, we find that he gives directions for the centi-
grade method of testing, and Mr. John Gough Watson, his
pupil, informs me that he used it constantly. Ho says,*

* Mem. Phil. Soc, Vol. III., new scries, p. 59, 1>^I4.

252 MEMOIR OF DR. DALTON, AND

" The improvements I would propose in the use of tests
are, that the exact quantities of the ingredients in each
test should be previously ascertained and marked on the
label of the bottle; this might easily be done in most of
them in the present state of chemical science. We should
then drop in certain quantities of each from a dropping
tube graduated into grains till the required effect was pro-
duced; then from the quantity of the test required, the
quantity of saline matter in the water might be determined
without the trouble of collecting the precipitate; or if this
was done, the one method might be a check upon the other."
This method of testing, which promises to be of such great
value in saving the time of chemists, was then clearly seen
by him, although it has taken several workers in the field to
bring it into use in the laboratory, chemists, like others,
being difficult to move into a new train of thinking and act-
ing. At the same time the mere advice is not enough, it is
needful to show how it may be accomplished in various in-
stances ; this, Dalton did partially. He gave the right
directions as a master, leaving it for a long train of workmen
to carry out his ideas. Still we see clearly that he was accus-
tomed to use the graduated dropping tube, and analyze by
volume. He gives directions for taking the alkalinity of
water by the use of acids, and adds, that " these acids may
be considered as sufficient for tests of the quantity of lime
in such waters, and nothing more is required than to mark
the quantity of acid necessary to neutralize the lime." Here
we see that he was accustomed to take the alkalinity of waters
for the carbonate of lime.

There is certainly a change in the style of these memoirs,
there is less care, there are opinions thrown out and un-
finished experiments which do not directly lead to benefit,
and there is a diminished desire to give the ultimate laws on
which phenomena depend. The mind had evidently felt that
something bad been achieved, which left it leisure and gave

HISTORY OF THE ATOMIC THEORY. 253

it also a right to be heard, even when it uttered only its sus-
picions. In these memoirs we find prominently brought for-
ward that intense faith in his own previous results, constantly
quoting what was obtained in his own mind in preference to
the results obtained by the whole world besides. This gradu-
ally led to a certain amount of egotism, and a conservative
belief that all work in that direction was completely finished,
so that he does not seem to look forward sufficiently to any
improvement or modification.

Instead of reviewing his later writings, I shall add here a
list more complete than has been yet given, although all the
papers were not viewed by him as important, and some were
merely given in all probability to supply an occasional want
of material at the meetings of the Literary and Philosophical
Society ; by a perusal of the titles some idea will be given of
his great fertility and diligence. These titles are taken from
the books of the Society. On reading them over, one is
compelled to wonder at the newness and youth of much of
our modern science, and to doubt, on that account, the
stability of not a few of its maxims; for we find that although
it is intended to represent the thoughts of nature, it is of itself
not older than "a man that shall die." After Dalton read his
first paper, Mr. Robert Owen read one on March 6th, 1795,
entitled " Thoughts on the connection between universal
happiness and practical mechanics;" and in 1797, " On the
origin of opinion with a view to the improvement of the
social virtues." Mr. Owen is still alive.

LIST OF DALTON'S PAPERS.

Read before the Members of the Manchester Literary and
Philosophical Society,

1. October 31st, 1794. Extraordinary Facts relating to
the Vision of Colors, with Observations.

2. November 27th, 1795. On the Color of the Sky, and
the relation between Solar Light and that derived from Com-

254 MEMOIR OF DR. DALTON, AND

bustion ; with Observations on Mr. Delaval's Theory of
Colors.

3. April 7th, 1798. Essay on the Mind, its Ideas, and
Affections ; with an Application of Principles to explain the
Economy of Language.

4. March 1st, 1799. A paper, containing Experiments
and Observations, to determine whether the quantity of Rain
and Dew is equal to the quantity of Water carried oiF by the
rivers and raised by evaporation ; with an Inquiry into the
Origin of Springs.

5. April 12th, 1799. Experiments and Observations on
the Power which Fluids possess of conducting Heat; with
Reference to Count Rumford's seventh essay.

6. June 7th, 1799. On the Color of the Sky, and the
relation betwixt Solar Light and that derived from Combus-
tion ; with Observations on Mr. Delaval's Theory.

7. April 18th, 1800. Experimental essays, to determine
the Expansion of Gases by Heat, and the maximum of
Steam or Aqueous Vapour, which any Gas of a given tempe-
rature can admit of; with observations on the common and
improved Steam Engines.

8. June 27th, 1800. On the Heat and Cold produced by
the Mechanical Condensation and Rarefaction of Air.

9. October 17th, 1800. Philological Inquiry into the
Use and Signification of the Auxiliary Verbs and Participles
of the English Language.

10. December 12th, 1800. Review of Dr. Herschel's Ex-
periments on the radiant Heat, and the Reflectibility and
Refrangibility of Light.

11. July 31st, 1801. Read Part 1st of Mr. Dalton's paper
on the Constitution of Mixed Gases, &c.

12. October 2nd, 1801. Read Part 2nd of Mr. Dalton's
paper on the Force of Steam, &c.

13. October 16th, 1801. Read Part 3rd of Mr. Dalton's
paper on Evaporation, &c.

HISTORY OF THE ATOMIC THEORY. 255

14. January 22nd, 1802. On the General Causes, Force,
and Velocity of Winds ; with remarks on the Seasons most
liable to high winds.

15. October 29th, 1802. On the Proportion of the seve-
ral Gases or Elastic Fluids, constituting the Atmosphere;
with an Inquiry into the Circumstances which distinguish the
Chymical and Mechanical Absorption of Gases by Liquids.

16. January I4th, 1803. On the Spontaneous Intercourse
of different Elastic Fluids, in confined circumstances.

17. October 7th, 1803. On the Absorption of Gases by
Water.

18. November 4th, 1803. On the Law of Expansion of
Elastic Fluids, Liquids, and Vapours.

19. February 24th, 1804. A Review and Illustration of
some Principles in Mr. Dalton's course of Lectures on Natural
Philosophy, at the Royal Institution, in January, 1804.

20. August 3rd, 1804. On the Elements of Chemical
Philosophy.

21. October 5th, 1804. On Heat.

22. November 30th, 1804. Review of Dr. Hope's paper
" On the Contraction of Water by Heat."

23. September 2nd, 1805. Remarks on Mr. Gough's two
Essays on Mixed Gases, and on Mr. Schmidt's, *'0n Moist
Air."

24. March 7th, 1806. On Respiration and Animal Heat.

25. February 6th, 1807. On the Constitution and Pro-
perties of Sulphuric Acid.

26. October 2nd, 1807. On Heat.

27. October 16th, 1807. On the Expansion of Bodies
by Heat.

28. January 22nd, 1808. On the Specific Heat of Bodies.

29. March 18th, 1808. On the Specific Heat of Gaseous
Bodies.

30. December 2nd, 1808. On the Measure of Mechanical
Force.

256 MEMOIR OF DB. DALTON, AND

31. December 16th, 1808. On Respiration.

32. March 10th, 1809. On Evaporation.

33. April 7th, 1809. On the Compounds of Sulphur.

34. November 3rd, 1809. On Muriatic Acid.

35. December 1st, 1809. On Sulphuric Acid.

36. March 9th, 1810. On Fog.

37. November 16th, 1810. Appendix to his Remarks on
Respiration and Animal Heat.

38. December 28th, 1810. On Hygrometry.

39. April 3rd, 1812. On Meteorology.

40. April 17th, 1812. Meteorology continued.

41. October 2nd, 1812. On the Oxymuriate of Lime.

42. January 8th, 1813. Experiments on Phosphoric Acid
and the Phosphates.

43. March 5th, 1813. Experiments and Observations on
the different Compounds of Carbonic Acid and Ammonia.

44. October 1st, 1813. On the Combinations of Gold.

45. October 15th, 1813. Continuation of the paper on
the Combinations of Gold.

46. November 12th, 1813. The Combinations of Platina.

47. December 10th, 1813. On the Cause of Chemical
Proportion, being remarks on a paper by Berzelius.

48. January 7th, 1814. Experiments on certain frigorific
Mixtures.

49. March 18th, 1814. Remarks tending to facilitate the
Analysis of Spring and Mineral Waters.

50. October 7th, 1814. On Metallic Oxides.

51. December 2nd, 1814. On Metallic Oxides. (Con-
tinued.)

52. January 27th, 1815. Critical remarks on some
modern Chemical Phrases.

53. November 17th, 1815. Remarks on Saussure*s Essay
on the Absorption of Gases by Liquids.

54. October 4th, 1816. On the chemical compounds of
Azote and Oxygen.

HISTORY OF THE ATOMIC THEORY. 257

55. December 13th, 1816. An Appendix to the Essay
on chemical compounds of Azote and Oxygen.

56. October 3rd, 1817. On Phosphurets, or the combina-
tions of Phosphorus with Earths, Alkalies, Metals, &c.

57. November 21st, 1817. Observations on Oxides and
Sulphurets.

58. November 13th, 1818. Observations on the Quantity
of Rain during the last Twenty-five Years; with Remarks
on the Theory of Rain.

59. December 11th, 1818. Summary of Observations on
the Barometer and Thermometer, made at Manchester for
the last 25 years.

60. January 8th, 1819. Experiments on the Force of the
Vapour of Ether, to show the fallacy of some of Dr. Ure's
Statements just published in the Philosophical Transactions.

61. April 16th, 1819. On Sulphuric Ether.

62. October 15th, 1819. On Alloys, particularly those of
Copper and Zinc, and Copper and Tin.

63. November 12th, 1819. On Amalgams, and other
Metallic Alloys.

64. December lOth, 1819. A Chemical Analysis of the
Mineral Waters of Buxton.

65. October 6th, 1820. On Oil, and the Gases obtained
from it by heat.

66. December 1st, 1820. On Alum.

67. January 26th, 1821. On Meteorology, or observations
on the Weather for the years 1819 and 1820, in Manchester.

68. February 9th, 1821. Observations on Meteorology,
particularly with regard to the Dew point, &c., or quantity of
Vapour in the Air.

69. October 5th, 1821. Some observations on the Salts
and Sulphurets of Iron.

70. November 30th, 1821. On the Effects of continued
Electrification on compound and mixed Gases.

71. December J 3th, 1822. On the Saline Impregnations

2L

258 MEMOIR OF DR. DALTON, AND

of the Rain which fell during the late Storm, viz., December
5th, 1822.

72. March 21st, 1823. Appendix to an Essay on Salt
Rain (read December 13th, 1822), with additional observa-
tions on the succeeding Storms of Wind and Rain.

73. November 14th, 1823. On the Nature and Properties
of Indigo; with directions for the valuation of different
samples.

7'1. December 26th, 1823. On various Alloys of Tin,
Zinc, Lead, Bismuth, Antimony, &c.

75. October 15th, 1824. On Associations for the Pro-
motion of the Physical Sciences, Literature, and the Arts.

76. November 12th, 1824. An Account of some Experi-
ments to determine the Light and Heat given out by the
combustion of diiferent Gases.

77. April 15th, 1825. Results of Meteorological Observa-
tions at Manchester, for Thirty-one Years ; with Remarks
upon them.

78. December 30th, 1825. On the Constitution of the
Atmosphere.

79. October 6th, 1826. On the Height of the Aurora
Borealis above the surface of the Earth, particularly the one
seen on the 29th of March, 1826.

80. November 4th, 1826. An Appendix to a paper read
on October 6th, on the height of the Aurora Borealis above
the surface of the earth.

81. November 26th, 1827. An Historical Sketch of the
Society's Library ; with an Account of its present state.

82. December 28th, 1827. Observations, chiefly chemical,
on the nature of the Rock Strata in Manchester and its vicinity.

83. October 17th, 1828. Summary of the Rain, &c., at
Geneva and at the elevated station of St. Bernard, for a series
of years, from the ' Bibliotheque Universelle' for March, 1828;
with Observations on the same.

84. January 8th, 1830. Physiological Investigations, de-

HISTOBY OF THE ATOMIC THEOEY. 259

duced from the Mechanical Effects arising from Atmospherical
Pressure on the Animal Frame.

85. January 22nd, 1830. Remarks on a Statement of the
Amount of Rain fallen at different places on the line of the
Rochdale Canal.

86. March 5th, 1830. On the Quantity of Food taken
by a person in health, compared with the Quantity of the
different Secretions during the same period ; with Chemical
Remarks on the several Articles.

87. October 15th, 1830. Chemical Observations on cer-
tain Atomic Weights, as adopted by different Authors ; with
some Remarks on the Notation of Berzelius.

88. October 29th, 1830. Observations on the Causes of
Colouring Matter.

89. November 23rd, 1830. Chemical Observations on
certain Atomic Weights, as adopted by different Authors;
with Remarks on the Notation of Berzelius.

90. January 21st, 1831. Meteorological Observations for
a period of thirty-seven years ; with Theoretical Remarks.

91. February 18th, 1831. On the Quantity of Oxygen
in Atmospheric Air.

92. December 2nd, 1831. On the Proportion of Oxygen
Gas in the Atmosphere.

93. January 13th, 1832. A Summary of Meteorological
Observations, for 1831, made in Manchester and the vicinity.

94. January 11th, 1833. Dr. Dalton's Remarks on the
Meteorology of the last year.

95. March 8th, 1833. Observations on the Anomalous
Vision of Colours.

96. November 1st, 1833. A Description of an imaginary
Aurora Borealis in the North of England.

97. February 7th, 1834. An Account of Meteorological
Observations, at Manchester and other places, in the year 1833.

98. March 7th, 1834. Some Remarks on Clouds: their
Nature, Height, &c.

260 MEMOIR OF DB. DALTON, AN0

99. October 17th, 1834. Observations on certain Liquid*
obtained from Caoutchouc by Distillation.

100. December 26th, 1834. Observations on the various
accounts of the Luminous Arch or Meteor accompanying the
Aurora Borealis of November 3rd, 1834.

101. February 20th, 1835. Account of Meteorological
Observations, made in Manchester and other places, in 1834,

102. October 2nd, 1835. Read a paper by Dr. Dalton.
(Subject not named in the Journal.)

103. February 15th, 1836. An Account of Meteorological
Observations, made in Manchester and other places in 1835.

104. October 2 1st, 1836. Sequel to an Essay on the
Constitution of the Atmosphere; read to the Society in the
year 1825. Part 1.

105. November 4th, 1836. 2nd Part of a paper entitled
" Sequel to an Essay on the Constitution of the Atmosphere."

106. October 2nd, 1838. On Arseniates and Phosphates.

107. February 5th, 1839. Some Account of Meteoro-
logical Observations, made in Manchester, in the years 1836-
37-38.

108. October 1st, 1839. On the Ammoniaco-Magnesian
Phosphate, as it was formerly called ; or the Tribasic Phos-
phates of Magnesia and Ammonia, as Professor Graham has
called it. And on the Phosphate of Soda and Ammonia, or
Microscopic Salt, as it was formerly called; and now Tribasic
Phosphate of Soda and Ammonia and Water, of Professor
Graham.

109. March 31st, 1840. On the Quantity of Acids, Bases,
and Water in the different varieties of Salts; with a New
Method of Measuring the Water of Crystallization.

110. April 28th, 1840. Some Account of Meteorological
Observations, made in Manchester, in the year 1839.

111. October 6th, 1840. Continuation of a paper On
the Quantity of Acids, Bases, and Water in the different
varieties of Salts.

HISTORY OF THE ATOMIC THEORY. 261

112. January 12th, 1841. Meteorological Observations,
made in Manchester and the neighbourhood, during the year
1840, or previously.

113. March 9th, 1841. On a New and Easy Method
of Analyzing Sugar.

114. October 5th, 1841. On the Citric Acid, the Oxalic
Acid, the Acetic Acid, and the Tartaric Acid.

115. January lOth, 1843. Meteorological Observations,
at Manchester, made in the year 1842.

116. April 16th, 1844. On the Fall of Rain, &c., &c.,
in Manchester, during a period of 50 years.

Some of these were embodied in other works or printed
elsewhere.

In Nicholson's Journal.

New Theory of the Constitution of Mixed Gases eluci-
dated. Vol. III., p. 267. November 18th, 1802.

Letter from Mr. Dalton, containing Observations concern-
ing the Determination of the Zero of Heat, the Thermome-
trical Gradation, and the Law by which dense or non-elastic
Fluids expand by Heat. Vol. V., p. 34. April 20th, 1803.

Correction of a mistake in Dr. Kirwan*s Essay on the State
of Vapour in the Atmosphere. Vol. VL, p. 118. August
22nd, 1803.

On the supposed Chemical Affinity of the Elements of
Common Air; with Remarks on Dr. Thomson's Observa-
tions on that subject. Vol. VIII., p. 145. June 16th, 1804.

Observations on Mr. Gough's Strictures on the Doctrine
of Mixed Gases, &c. Vol. IX., p. 89. September8th, 1804.

Facts tending to Decide the Question at what Point of
Temperature Water possesses the greatest Density. Vol. X.,
p. 93. January 10th, 1804.

Extract of a Letter from Mr. J. Dalton : On a remarkable
Aurora Borealis. Vol. X., p. 303. March 12th, 1805.

262 MEMOIR OF DE. DALTON, AND

Remarks on Count Rumford's experiments relating to the
maximum density of water. Vol. XII., p. 28. August 17th,
1805.

Investigation of the Temperature at which Water is of the
greatest Density, from the Experiments of Dr. Hope, on the
Contraction of Water by Heat at low temperatures. Vol. XIII.,
p. 377. April I4th, 1806. And Vol. XIV., p. 128. May
12th, 1806.

Inquiries concerning the signification of the word particle,
as used by modern chemical writers, as well as concerning
some other terms and phrases. Vol. XX VIII., p. 81.
December 19 th, 1811.

Remarks on Potassium, Sodium, &c. Vol. XXIX., p. 129.
May nth, 1811.

Observations on Dr. Bostock's Review of the Atomic
Principles of Chemistry. Vol. XXIX., p. 143. May 15th,
1811.

In Thomson's ^'Annals of Philosophy,''

Further Observations and Experiments on the Combinations
of Oxymuriatic Acid with Lime. Vol. II., p. 6. 1813.

Remarks on the Essay of Dr. Berzelius, on the Cause of
Chemical Proportion. December 24th, 1813. Vol. III.,
p. 174. 1814.

Vindication of the Theory of the Absorption of Gases by
Water, against the conclusions of Saussure. Vol. VII., p.
215. 1816.

On the Chemical Compounds of Azote and Oxygen, and
on Ammonia. Vols. IX., p. 186, and X., p. 38 and 83.
1817.

On Phosphuretted Hydrogen. Vol. XL, p. 7. 1818.

On the Combustion of Alcohol, by the lamp without flame.
Vol. XII, p. 245. 1818.

On the Vis Viva. Vol. XII., p. 444. 1818.

HISTORY OF THE ATOMIC THEORY. 263

In Phillips 8 ''Annals of Philosophy r
On the Analysis of Atmospheric Air by Hydrogen.
Vol. X. N. S.

In the ''Philosophical Transactions"

On the Constitution of the Atmosphere. 1826.
On the Height of the Aurora Borealis. 1828.
Sequel to an Essay on the Constitution of the Atmosphere ;
with some Account of the Sulphurets of Lime. 1837.

In the "Annales de Chimie"

Sur 1* Hydrogene Phosphure. (Extract of a Letter ad-
dressed to the Royal Academy of Sciences.) Vol. VIL 1817.

In a Separate Form, 1840.

Essay on the Phosphates and Arseniates.

On Microcosmic Salt.

On the Mixture of Sulphate of Magnesia and the Diphos-
phate of Soda.

Essay on the Quantity of Acids, Bases, and Water in the
different varieties of Salts ; with a New Method of Measuring
the Water of Crystallization as well as the Acids and Bases.

On a New and Easy Method of Analyzing Sugar.

His "Meteorology," 1793.

"Grammar," 1801.

"New System of Chemistry," Part 1, 1808— Part 2,
1810; Vol. IL, Part 1, 1827.

A new edition of Vol. I., Part 1 , appeared in 1842, and a
new edition of his Meteorology in 1834.

His many letters to periodicals in his youth need not be
specially enumerated.

These labours did not pass unnoticed in this country, and
still less, I may say, in foreign countries. In 1816, the
French Academy elected him a Corresponding Member,

264 MEMOIR OF DR. DALTON, AND

although not yet a Member of the Royal Society of his
own country.

Productions so numerous as these will account for all
the years that Dalton had to spend. We find him still gain-
ing his living as professional chemist, lecturer, and teacher of
chemistry and mathematics; sometimes giving evidence on
subjects connected with the arts, at trials in various courts ;
sometimes answering the inquiries of manufacturers. His
uncertain position in this respect, suggested to Sir H. Davy
that he might probably find it agreeable to undertake the
scientific department of an expedition, fitted out by the
Admiralty, for investigation in the Polar regions, under Sir
John Ross. In 1818, Davy wrote to inquire if he would
undertake it, but Dalton excused himself, partly on account
of the hardships connected with a journey which, to one ac-
customed to a sedentary life, would be found too severe;
and partly because he did not wish to interrupt his chemical
inquiries. It is almost to be regretted that he did not under-
take some such expedition. A new direction would have
been given to his investigations; and a mind which had
almost expended itself on its own field of view, would have
had an ample new field on which new crops would, in all
probability, have flourished abundantly.

About the same time, Mr. Strutt, of Derby, offered him
a laboratory and a home at his house, with a salary of
four hundred pounds a-year, and perfect freedom to spend
his time in any manner he might consider agreeable. This
he declined, on account of the loss of independence which he
considered it would necessarily involve, although the offer was
made on such terms as to free him from all duties whatever.
This information I received from Alderman Shuttleworth, of
Manchester, through whom the offer was made. But no
professorship was offered him, none of the rich endowments
of the country benefited Dalton. With a strange apathy
these are seldom offered but to those who propose themselves ;

HISTORY OF THE ATOMIC THEOBY. 265

there is no seeking out of talent, on which to confer oppor-
tunities of usefuhiess; and reward, which is an object less
desired by men of elevated minds, comes only after the
clamorous entreaties of friends.

The Royal Society had paid no attention to him, because
constituted like many of the other public bodies of the
country, receiving its strength by the vigour of individuals
moving towards it, and so standing more in the condition of
a reservoir than of a fountain. Davy proposed, in 1810, to
nominate him, but he declined; probably the expense was
the hindrance. There certainly are cases in which such a
hindrance should not be permitted. In 1822, he was pro-
posed and elected without his consent being asked, lest a true
nolo episcopari should have again been uttered. It was in
the summer of the same year that he visited Paris, and there
had that distinguished reception and entertainment among its
scientific men, that he might have looked for here in vain.
His reception in Paris pleased him much ; he returned much
refreshed and invigorated in mind ; he formed high opinions
of many of the celebrated characters he met there, and the
visit was spoken of with pleasure to the end of his life.

If the customs or laws of the Royal Society prevented
them from early electing him, they took the first opportunity
in their power of presenting him with the gold medal. In the
discourse* of Sir H. Davy, on that occasion, we have his
matured opinion on Dalton's position and discoveries. He
there says that the medal was given " for the development
of the chemical theory of definite proportions, usually called
the atomic theory, and for his various other labours and dis-
coveries in physical and chemical science." His speech at
this time must be taken as his matured opinion on the subject
of the atomic theory, whatever he may have in private said
or been reported to say. It continues: "To- Mr. Dalton

• Page 1^5, "Six discounes delivered before the Royal Society," by Sir H.
Davy.

2M

266 MEMOIR OF DR. DALTON, AND

belongs the distinction of first unequivocally calling the atten-
tion of philosophers to this important subject. Finding that in
certain compounds of gaseous bodies, the same elements
always combined in the same proportion ; and that when
there was more than one combination, the quantity of the
elements always had a constant relation, such as 1 to 2 or
1 to 3, or to 4, he explained this fact on the Newtonian
doctrine of indivisible atoms, and contended that, the rela-
tive weight of one atom to that of any other atom being
known, its proportions or weight in all its combinations
might be ascertained ; thus making the statics of chemistry
depend upon simple questions in subtraction or multiplica-
tion, and enabling the student to deduce an immense number
of facts from a few well authenticated, accurate, experimental
results." He then mentions Bryan and William Higgins
and Richter, saying, that *' it is difficult not to allow the
merits of prior conception as well as of very ingenious
illustration to" W. Higgins. He expresses Richter's views
very neatly, saying, " In his New Foundations of Chemistry,
published in 1795, he has shewn that when neutro-saline
bodies in general undergo mutual decomposition, there is
no excess of alkali, earth, or acid; and he concludes, that
these bodies are invariable in their relation to quantity, and
that they may be expressed by numbers." He, however,
continues to say,* " Mr. Dalton's permanent reputation will
rest upon his having discovered a simple principle univer-
sally applicable to the facts of chemistry, in fixing the
proportions in which bodies combine, and thus laying the
foundation for future labours respecting the sublime and
transcendental parts of the science of corpuscular motion.
His merits in this respect resemble those of Kepler in astro-
nomy.— Mr. Dalton has been labouring for more than a
quarter of a century with the most disinterested views. With
the greatest modesty and simplicity of character he has re-

* Page 129.

HISTOET OF THE ATOMIC THEORY. 267

mained in the obscurity of the country, neither asking for
approbation nor offering himself as an object of applause. He
is but lately become a fellow of this society, and the only com-
munication he has given to you is one, compared with his
other works, of comparatively small interest; their (i.e. the
council's) feeling on the subject is therefore pure. I am sure he
will be g^tified by this mark of your approbation of his long
and painful labours. It will give a lustre to his character which
it fully deserves ; it will anticipate that opinion which posterity
must form of his discoveries ; and it may make his example
more exciting to others in their search after useful knowledge
and true glory."

Soon after this, in 1827, the first part of the second volume
of his new system of chemistry was published, and we there
see how the science would have grown had it been under the
hand of Dal ton alone. A vigorous hand he certainly had, but
there were hundreds eagerly giving their attention to chemistry
over all Europe, for the love of knowledge, of fame, and of
humanity, so that it was driven impetuously forward, and under
the direction of his own theory, had entirely left him behind ;
he was outrun by his own disciples ; left alone by those who
without him would not readily have moved.

In this volume he gives an account of the theory of the
elementary nature of chlorine, but evidently without full belief,
retracts gracefully his somewhat hazardous opinion that fluo-
rine was a higher oxide of hydrogen than water, and uses the
expression ** oxide of potassium and sodium," without much
disinclination. He was therefore willing to change his opinion,
but in reality he had been so many years working to collect
material for his book, that this volume was left behind before it
was published. His dislike to much reading was found to be
an injury to him, and many years of his life were thus found
to be of little value to science. We must, therefore, in his
public capacity view him now chiefly as one whose work was
finished and who was enjoying the fruits of his labours.

268 MEMOIR OF BR. DALTON, AKD

although at the same time he seems to have worked as con-
stantly as ever, retaining the original habits but not display-
ing the original vigor. To work too long in one vein seems
to be highly injurious, as the vein narrows the labour increases
in greater proportion than the yield, and it is better for us to
return to the main centre of the mine, leaving the distant
veins to be worked out when the approaches shall have
gradually become easier.

In 1830, the Academy of Sciences at Paris elected him
foreign associate, in the place of Davy. Of this addition to
his scientific rank in that society, he was unreservedly proud.
As if his own country were constantly to be behind in his
recognition, we find that in the year 1832, Oxford elected
him doctor of civil laws. This title of D.C.L., given at the
recommendation of Dr. Daubeny, was one which he seldom
omitted after his name ; the simplicity of his mind did not
allow him at all to disguise the pleasure with which it was
viewed.

Being now advanced in years, his friends were anxious to
secure for him an age less laborious than his life had been.
With small means, he had still saved some money, but too
little for the support of his declining strength during the
years of his probable life. We are told by Dr. Henry, that
Mr. Babbage first suggested the propriety of applying to
government for a pension, whilst Mr. Geo. W. Wood and Mr.
Poulett Thomson were most active in obtaining it.

Dr. Henry informs us that the first answer the Lord Chan-
cellor gave was, that he " was anxious to obtain some provision
for him, but that it was attended with great difficulty." This
is an expression at which we cannot be too much astonished,
but there is no doubt of its truth, even if it did not sound
highly probable. Were there so many superior men pressing
on the treasures of the country that it was difficult to obtain a
pittance for Dalton ? The same defect again shows itself, there
is no spontaneous movement, but every man must thrust himself

HISTORY OF THE ATOMIC THEORY. 269

or be thrust forward by his friends, and after having done his
work by many struggles, another struggle must be made for
the reward.

The following letter, written by Dr. William Henry, his
intimate friend the celebrated chemist, was sent along with
the formal application to government. Its beauty and truth
demand for it a place in every memoir of Dalton.

DR. HBNRY TO C. BABBAGE.

" Mr. Dalton never had, nor was ever given to expect any
reward or encouragement whatsoever from government, and
having been in habits of unreserved communication with him
for more than thirty years, I can safely aver that it never
occurred to him to seek it. He has looked for his reward to
purer and nobler sources ; to a love of science for its own sake ;
to the tranquil enjoyments derived from the exercise of his
faculties, in the way most congenial to his tastes and habits,
and to the occasional gleams of more lively pleasure, which
have broken in upon his mind, when led to the discovery of
new facts, or the deduction of important general laws. By
the moderation of his wants and the habitual control over his
desires, he has been preserved from worldly disappointments,
and by the calmness of his temper and the liberality of his
views, he has escaped those irritations that too often beset men
who are over anxious for the possession of fame, and are im-
patient to grasp prematurely the benefits of its award. For
a long series of years he bore neglect and sometimes even con-
tumely, with the dignity of a philosopher, who though free
from anything like vanity or arrogance, yet knows his own
strength, estimates correctly his own achievements, and leaves
to the world, generally although sometimes slowly just, the
final adjudication of his fame.. Among the numerous honours
that have since been conferred on him by the best judges of
scientific merit in this and other countries, not one has been
sought by him. They have been without exception spon-

270 MEMOIR OF DR. DALTON, AND

taneous oflferings, prompted by a warm and generous approba-
tion of his philosophical labours, and by the desire to cheer
him onward in the same prosperous career. Deeply as he
has felt these distinctions, they have never carried him beyond
that sober and well regulated love of reputation, which exists
in the purest minds, and is one of the noblest principles of
action.

" In perfect consistency with Mr. Dalton's intellectual quali-
ties are the moral features of his character, the disinterested-
ness, the independence, the truthfulness, and the integrity
which through life have uniformly marked his conduct towards
others. He has been taxed with plagiarism, but never was a
charge more completely unfounded. Not only is he incapable
of encroaching on the just rights of others, but even of taking
tacitly to himself applause to which he does not feel that he
is fully entitled. Of the work from which he is accused of
having borrowed the outline of his atomic theory he had never
once heard, until many years after the publication of his
opinion on that subject. Nor is this at all extraordinary when
it is considered that men like Mr. Dalton, of original and
creative minds, trust rather to their own powers of research
than to reading ; and in the know^ledge of the history of science
are often surpassed by very inferior persons. This general re-
mark applies to Mr. Dalton ; but he is a discoverer in the true
sense of the word. He has drawn from observed phenomena
new and original views — upon these views he has founded dis-
tinct conceptions of a general law of nature ; — he has traced
out the conformity of that law with an extensive class of facts,
many of which he himself first revealed by well-devised
experiments, and he has thus secured an admiration not by
having broached ingenious opinions merely, but by having
worked out the evidences of those opinions by labours most
sagaciously and perseveringly applied. Nor is it on the
atomic theory only that his reputation must rest. It has a
broader basis in his beautiful and successful investigations

HISTORY OF THE ATOMIC THEOKY. 27 1

into the subject of heat; into the relations of air and moisture
to each other; and into a variety of other topics intimately
connected with the stability and advancement of chemical
philosophy. I therefore agree with you that Mr. Dal ton has
strong claims upon the national respect and gratitude, and
contend for his title to reward, even though he may not
have accomplished anything bearing strictly upon the im-
provement of those arts and manufactures, which are the
chief sources of our national wealth. For let it be remem-
bered, that every new truth in science has a natural and
necessary tendency to furnish, if not immediately, yet at
some future time, valuable rules in art* Nothing is more
common than that a general principle, when first developed,
may admit of no obvious practical use; but that a few
subsequent discoveries, made perhaps at a small expense of
genius or labour, supply links which render it available first
to individual, and in due course to public wealth and pros-
perity. Not to mention other instances, Mr. Watt derived
from Dr. Black's discovery of latent heat, a guiding light to
the noblest invention that has ever been placed in the hands of
man, for giving him control over the physical world, and even
for advancing his progress in moral and intellectual cultiva-
tion. The discovery of chlorine also in the laboratory of a
retired chemist, brought forth no practical results for several
years, but when found by a subsequent philosopher to quicken
the whitening of unbleached cotton and linen goods, it was
immediately applied by practical men to the art of bleaching,
and no one can now calculate its immense influence in giving
rapid circulation to the capital employed in the cotton and
linen manufactures. Among the abstract truths unfolded by
Mr. Dalton, it would not be difficult to point out the germs
of future improvements in the practical arts generally, germs
which now lie dormant in the shape of purely scientific pro-
positions.

'< But were it otherwise it would surely be unworthy of a

272 MEMOIR OF DR. DALTON, AND

great nation to be governed in rewarding or encouraging
genius by the narrow principle of a strict barter of advantages.
With respect to great poets and great historians, no such par-
simony has ever been exercised. They have been rewarded,
and justly, for the contributions they have cast into the trea-
sury of our purely intellectual wealth. And do not justice
and policy equally demand that a philosopher of the very
highest rank, one who has limited his worldly views to little
more than the supply of his natural wants, and has devoted
for more than forty years the energies of his powerful mind to
enlarging the dominions of science, should be cherished and
honoured by that country which receives by reflection the
lustre of his well-earned fame ? The most rigid advocate of
retrenchment and economy cannot surely object to the moderate
provision, which shall exempt such a man in his old age
from the irksome drudgery of elementary teaching, and shall
give him leisure to devote his yet vigorous faculties to review-
ing, correcting, applying, and extending what he has already
in great part accomplished. In one instance of recent date, a
philosopher who has eminently distinguished himself in purely
abstract science, has received the merited reward of a pension
for life. It is most desirable then that the British govern-
ment, by extending its justice to another not less illustrious,
should be spared the deep reproach which otherwise assuredly
awaits it, of having treated with coldness and neglect one
who has contributed so much to raise his country high among
intellectual nations, and to exalt the philosophical glory of
the age."

The application met with success, and at the meeting of
the British Association in Cambridge, it was announced by
Professor Sedgwick, that the king had granted a pension of
£150 to Dalton. This announcement, in the beautiful lan-
guage of that eloquent man of science, has been frequently
quoted, and is well known.

HISTORY OF THE ATOMIC THEOKY. 273

In 1836 the pension was increased to £300, but two years
previously his brother Jonathan died, leaving for him as
heir the paternal estate, which now made him comparatively
wealthy. He, however, according to his strength, still con-
tinued working. So late as 1840 he published four essays,
with the title " On the Phosphates and Arseniates ; Microcos-
mic Salt; Acids, Bases, and Water; and a New and Easy
Method of Analysing Sugar."

Here we have another instance of his old method of striking
roughly in a new direction, and deciding at once on the whole
district, little caring who was to come after to examine. He
says, p. 10, "The new method of ascertaining the quantity
of water in the salts is now to be discussed. I have a bottle
with a stopper which just contains 572 grains of pure water,
when the stopper is put on and wiped clean and dry, at the
temperature of 60° Fahr. A graduated tube or jar is necessary,
of 5in. or 6in. long and one quarter of an inch in diameter,
to measure exactly to a grain of water. A platina wire is
appended to the neck of the bottle, so as to be weighed more
conveniently. An ounce, more or less, is to be weighed of
any salt ; it is then to be put into the bottle, capable of con-
taining 572 grains of pure water (the water having been
carefully tansferred into another glass vessel of more ample
dimensions), and the salt dissolved and carefully transferred
and weighed in the 572 bottle again, and the spare liquor, if
any, is to be put into the narrow graduated tube.

" We have then 572 of pure water, + the pure water of
the salt 4- the solid (or liquid water of the salt whatever it
may be), all together in a liquid form, in the bottle and the
narrow tube. I was greatly surprised at the results. If the
salt was anhydrous, it would all go into the bottle exactly
filling it to a grain ; showing that the salt enters the pores of
the water.

" If the salt contained water, the quantity of water was

2N

274 MEMOIR OF DR. DALTON, AND

measured by the narrow tube in all cases whatever, showing
that the solid matter had in reality entered the pores of the
water."

This principle he applied to the analysis of sugar, showing
that its bulk in solution was equal to the amount of oxygen
and hydrogen combined as water, the carbon not occupying
any room. This rule Dal ton considered as absolutely and
universally true. He called it " the greatest discovery next
to the atomic theory." This idea in the hands of Messrs.
Playfair and Joule has had a fertile expansion, although
Dalton's mode of expressing the law has been limited to
certain classes of salts.* Had time and strength been given
him, he would no doubt, after this commencement, have
laboured well in the field of ''atomic volume."

It is well when men become aware of the failure of their
powers, and are willing to give up their places to those whose
minds are in full vigor. The essay on the phosphates and
arseniates affords, on page 12, a melancholy instance of the
fate of those who overrate their strength. This sentence
occui-s in the form of an epitaph. — " I sent the account of the
phosphates and arseniates to the Royal Society, for their in-
sertion in the transactions. They were rejected. Caven-
dish, Davy, Wollaston, and Gilbert are no more." It sounds
like an epitaph on himself, and the volume tells still more
plainly that he had not followed the increased exactness re-
quired in science. Nevertheless, in one respect, the last
pamphlet is a model of himself, the rapid, hasty work, the
carelessness of the labours of others, and the new field struck
out in his remarks on sugar. In one point, however, it fails ;
in his early life he did not work otherwise than on the most
advanced ideas ; amongst the phosphates and arseniates he had
receded.

The position which Dalton had attained seemed to demand

• See "Memoirs of the Chemical Society." Vol. II., &c.

HISTORY OF THE ATOMIC THEORY. 275

some public demonstration of honor in the town he had
so long adorned, and his declining years suggested a permanent
memorial. In 1834 his friends decided on having a marble
statue, which should present a correct likeness, and for this
purpose Chantrey was selected as the most suitable sculptor.
Chantrey seems to have entered on the task with pleasure,
and he has done it well. This statue is in the entrance hall
of the Royal Institution, in Manchester ; the trustees having
charge of it on condition that no one shall be refused per-
mission to look at it. Dr. Henry says the likeness is more
ideal than the reality, a refinement being given to the coun-
tenance which did not exist in the bust which Chantrey first
took and used as a model when engaged on the full figure.
Dr. Henry's intimate knowledge of Dalton must prevent any
one from entertaining a very different opinion, but a daguerreo-
type profile now before me taken from life,* shews not only the
marked features of the thinker, which no one has denied as
they were striking, but that peculiar refinement which gives
the idea of the student and the gentleman. This small photo-
graph on a silver plate, is exactly similar to the head so
beautifully engraved by Stephenson, I suppose indeed that
it served as the copy ; every expression is the same, and every
fold ofthe abundant white hair, nor can I see that the engraver
has increased the refinement, although he has probably some-
what heightened the forehead.

In the same year, I believe, he was presented at court, a
place that seemed scarcely to suit such a man, but he seems
to have had no desire to evade any of his natural claims to
honor, taking them as a necessary consequence of his work,
neither too highly elated like the great majority who are
honored, nor painfully retiring like Cavendish.

Being a Quaker, and not able to wear a sword, he was
taken in the scarlet robes of an Oxford Doctor of Laws, and

* ThU belongs to Mr. John Parry, who assisted in taking it.

276 MEMOIR OF DR. DALTON, AND

although it was feared that scarlet would scarcely suit one of
the Society of Friends, Mr. Babbage, who took him, remarked
that as he had a " kind of colour blindness, all red colours
appeared to him of the colour of dirt." Mr. Babbage adds,
" besides, I found that our friend entertained very reasonable
views of such mere matters of form;" a remark perfectly
true. Dalton was no bigot or formalist. The ceremony was
rehearsed beforehand by his friends, and it passed over well,
but not without remark on the length of time that he remained
before the king, who detained him long enough to ask him
several questions. Some say that Dalton, not imagining that
he had to pass on without a word of conversation, had waited
to be spoken to, and somewhat embarrassed his Majesty, in
his desire to be civil, to find suitable questions to put to
him. But Dalton had learnt his part well, and the reason
of the honor that he had of staying a few seconds longer
than anyone else, until people began to ask who he could
be, is more likely to have been caused by the fact which
Mr. Babbage mentions, that the king was informed of the
unusual presentation by Lord Brougham, who was Lord
Chancellor at the time, and nominally presented him.

Honors of various kinds soon became familiar to him,
such as fellowships of societies and degrees from universities,
of which the title of LL.D., from Edinburgh, was one.
They came upon him as on one to whom they were welcome,
but remained entirely external to him; his life had been
complete without their aid, and it was too late for them to
find a perfect sympathy either in his intellect or his habitual
feeling.

It is to be regretted that Miss Johns has not preserved more
about Dalton, as she had the ability and also his confidence ;
we might have obtained through her means a better picture
of his mental and moral phases. In the year 1830, when the
Johns family left the town, Dalton took a house close to their

HI8T0KY OF THE ATOMIC THEORY. 277

old residence and from that time lived alone. In 1832, at the
age of 66, he ascended Helvellyn as firmly as ever, took the
ladies an excursion in Cumberland to see his old friends, play-
fully introducing the two elder Miss Johns as his daughters,
and their cousins, the younger ladies, as his granddaughters.
But we cannot follow him on the hills; of them he never
seems to have wearied, nor did he ever weary of his old friends
there, nor of the study which first made him look on the
peculiar aspects of nature at that spot. The place seemed
to be a memory both for his intellect and his heart, and his
love for the district shows how permanent in him were the
feelings of both.

It was not until 1837 that Dal ton felt in any decided manner
the progress of age, although long before that time his energy
and originality had diminished. Properly speaking he had,
like many other gifted persons, only one period of great
originality, occurring immediately at the conclusion of his
education, so to speak. At that period it frequently happens
that the mind makes choice of the materials with which it
will work, and has some more or less distinct idea of the
conclusion, whilst the rest of the life is directed to its elucida-
tion or expansion.

On April 18th, 1837, he was disabled for a while by
paralysis, and although he wrote some memoirs after this period
he never entirely recovered. He fell suddenly to the floor after
his usual morning's labor of recording the state of the baro-
meter and thermometer. His friend Peter Clare was his con-
stant companion, and to the end of his life acted both as secretary
and friend, with an amount of 'reverence and affection that is
seldom found. He noted down the observations when Dalton
was ill, and took down at his request all the minute par-
ticulars connected with his illness and his medicines ; for every
illness and every dose was like a chemical experiment with
Dalton.

278 MEMOIR OF DR. D ALTON, AND

In six weeks he had recovered, but on February ISth, 1838,
he was again attacked, and was left very much enfeebled.
His habits were not changed ; idleness did not follow on weak-
ness ; he still made his experiment, but took, as he said, four
times longer to perform it ; still saw his friends, and kept up
the average of his cheerfulness, although the sad feeling that
his frame had decayed, was not absent from his mind. Of
this he gave little indication, but when the conversation hap-
pened once to turn upon an eminent scientific man whom he
admired, and had seen in France, he said, "Ah ! he was a
wreck then as I am now."

Mr. Ransome, once his pupil, and latterly his friend and
medical attendant, informs us that from 1838 he required con-
stant attendance, although he had no other attack until near
his death. During the 1843-4 session of the Literary and
Philosophical Society, he attended occasionally, where since
1817 he had been president. He had then lost his strength
so much, that to walk across the two intervening streets
to his own house in Faulkner-street, leaning on the arm of
Mr. Clare, was a great exertion. His speech was feeble and
inarticulate, so that he did not attempt to address the society.
On May 20th, 1844, another slight fit occurred. Still
we find him at his work, feebly, but regularly putting down
his metereological observations. His earliest thoughts were
on science, and they endured to the latest period of his life.
On July 26th his servant observed that his hand was unusually
tremulous, but, as Dr. Wilson observes, " there was the same
care and corrective watchfulness manifested in the last stroke
of his pen." He had written down " little rain this," and ob-
serving after a while that he had left out " day," he returned to
complete it. On the morning of the 27th, about six o'clock,
his attendant left him for a little, enforcing on him the propriety
of not moving until his return. His feeble limbs had not
even then got reconciled to perfect helplessness ; he seems to

HISTORY OF THE ATOMIC THEORY.

279

have made an attempt to rise, but fell from the bed, and was
found with his head on the floor, perfectly lifeless.

Mr. Harland, in the Manchester Guardian of the period,
gives a copy of the last three lines he wrote : they will serve
as an illustration of his method.

Month.

Hour.

Ther.
in.

Ther.
out.

1

Wind.

1

Rain.

ETap.

Remarks.

July 26th.

8

65

75

30.03

S.W.

1

13

65

73

30.10

Sy.

1

21

60

71

30.18

S.W.

1

LitUe

Rain

He had ceased for some months to make observations on
the amount of rain and evaporation. Mr. Harland reckons
his total observations at 200,000.

His life ended with science, and these few of his observa-
tions are therefore not out of place even when recording that
solemn moment. So calm had been his life, that it is not
surprising that in death his countenance should show a " beau-
tiful repose," as the same writer observed in a memoir fitted
for a more permanent place than a newspaper.

Many would like to know something more of Dalton's
religious faith, and would expect to learn from his con-
cluding words the hope and direction of his spirit, as if from
its position at that moment they were able to calculate the
angle of its divergence from earth. But that spirit had ceased
to find utterance for itself, and we are compelled to look at
the more solid points of a laborious lifetime. Scientific men
are often far from orthodox Christianity, although sometimes
living like saints, lives of purity, charity, devotion, and deep
reverence. Dalton " did justly," he " loved mercy," he
"walked humbly," he remembered carefully, as his will
especially shews, the mercy due to " the fatherless and widows,"
and all our accounts speak of him as one to all appearance in
an unusual degree "unspotted from the world." His profession

280 MEMOIR OF DR. DALTON, AND

was according to the spiritual, but inexpressive forms of the
Society of Friends.

As is usually the case on the death of an eminent man, the
first proof is furnished to many persons that he was once alive.
It was suddenly known that a man of eminence had left us,
and the greatest desire was shown to do his memory justice.
Although the body oi Friends to whom he belonged objected,
the funeral was given up to be conducted by the authorities
of the town. The remains, in a lead coffin enclosed in a solid
oak one, were placed in the Town Hall, and for some days a
constant flow of silent and gazing spectators passed through
the building. Some objected to this form ; but it is not easy
to say what in such cases should be done. True honor can
be given only by the mind and by the heart ; but to honor
any man publicly it is not enough that we feel it; it must
be expressed. This was a solemn method of impressing it
on all the forty thousand visitors, as well as on all the town
and neighbourhood, who were aware of what was going on,
and one probably which would leave a greater impression
than a speech over the grave, heard only by a few. True,
there was the explanation of his greatness wanted, but that
can be given only to a few at a time, and in place of that
there was the long continuation of the ceremony which, united
with a full account of Dalton's life given in the Manchester
Guardian^ impressed the fact on many and enabled everyone
to know why this man was so peculiarly selected for honour.

The funeral took place on the 12th of August. The train
was nearly a mile in length, including most of the public
bodies of the town, numerous private friends, and still more
admirers on foot or in carriages. The town was occupied
for a time with the burial of Dalton ; the business ceased ; the
streets were thronged with numberless spectators ; and the
police of Manchester attended with a badge of mourning. The
burial took place in the Ardwick Cemetery, on the south-east

HISTOBY OP THE ATOMIC THEOEY. 28 1

side of the city. The grave is enclosed by a strong rail, en-
closing a space about twenty feet square, and contains a very
plain and simple, but large, massive, and imposing covering of
polished red granite, with the inscription in large letters,
John Dalton, and in smaller letters the date of his birth
and death.

This tombstone, consisting of a solid granite pediment and
overhanging slab, was not made till some years after Dalton's
death, when a subscription was raised, amounting to £5,312, in
order to carry out some of his original intentions, as well as to
connect his name with some public benefaction, as a most
fitting memorial. Dalton had originally set aside two thousand
pounds for a " professorship of chenriistry at Oxford, for the
advancement of that science by lectures, in which the atomic
theory as propounded by me, together with the subsequent
discoveries and elucidations thereof, shall be introduced and
explained." The desire to repair the losses sustained by Mr.
Johns; to show a mark of respect and gratitude to Mr.
Peter Clare, who had been so aflfectionate as a friend ; and to
Mr. Neild, at whose table he had been welcomed regularly
for many years, seems to have caused him to alter his will,
and to attend rather to persons than to institutions.

His will included the names of many who were near and
dear to him and needed assistance.

With great respect for the affection shown in Dalton's will
to his friends and relatives, the sum mentioned was sub-
scribed to carry out in part his original intention. Since his
death Owens College had been founded in Manchester. For
this there have been provided two Dalton chemical scholar-
ships, of fifty pounds for two years ; two Dalton mathematical
scholarships, of fifty pounds, also continuing two years ; Dalton
prizes from ten to twenty-five pounds, and a Dalton natural
history prize of fifteen pounds.* A thousand pounds of the

• As ndrertiscd for 1850.
20

282 MEMOIR OF DR. DALTON, AND

money has been devoted to obtain a bronze statue, copied from
Chantrey's marble one. This has been considerably enlarged,
so as to suit its position at the right hand of the centre of the
Infirmary, the widest public space in Manchester, and beside
the statues of other distinguished persons.

Thus although in Manchester pure science is, from pecu-
liar circumstances, allowed only a humble station beside the
practical, and very few young men are allowed to study it
thoroughly, sufficient energy and enthusiasm have been found
to obtain for Dalton a memorial which connects his name as
well with the ornament of the city, as with the hopes of all
those youths whose aspirations lead them to seek eminence
or usefulness in the study of the natural sciences.

HISTORY OF THE ATOMIC THEOUT. 283

CHAPTER XIII.

D Alton's intellectual character.

The question of greatest interest and importance connected
with Dalton*s personality relates to the character of his mind,
not in a social point of view, for there we find that although
the qualities were of the best material, they were not made
prominent portions of his life, but intellectually in the faculty
which caused him to place himself in history and connect his
name with the knowledge of nature. Sir H. Davy has given
him the highest character, when he said that " he was one of
the most original philosophers of his time, and one of the most
ingenious," and when he says that he "had none of the
manners or ways of the world," and " was a very disinterested
man." But in his sketch we do not see that respect with
which a man having such a character ought to be treated. It
is said for example, that " he had no ambition beyond that of
being thought a great philosopher." Now this is a sneering
expression, but, after all, is it not expressive of the whole
aim of Davy's life ? Still, at his noble ambition no one has
ventured to sneer. Davy called it " glory," and united to his
scientific discoveries fine poetic diction, but his love of nature
was not so single as Dal ton's, and although his sight was more
delicate it was not so penetrating. There are few great men
who have not had their peculiarities ; when these arise from
simplicity of character they have generally been considered to
exalt their possessors. Davy's speculations on Dal ton's course
of thought are given at random. For example, he supposes
him to have seen the works of the Higginses, but not Ricbter's,

284 MEMOIR OF DR, DALTON, AND

whereas the contrary was the case, the works of the former not
having been heard of, but some of the latter. We are not
justified in making such speculations without some foundation.
This "character" referred to, written by Davy, and to be
seen in Dr. Henry's life of Dalton, might probably have been
modified before he gave it to the public, had he lived to do
so. He certainly had a right to jot down his own speculations
in private.

Dalton has been called a coarse experimenter. He taught
himself and never advanced with the times, but there are many
varieties of gifts, and we have not always found that the
finest experimenter has been the greatest discoverer. The
mind in reality makes the experiment first. Experiments are
not made on things distant from our knowledge, but on those
which approach nearest to it ; a theory is therefore formed,
arising from previous knowledge, or a question is asked with-
out a theory, exactly at the turning point where a finger post
is for a moment wanted. The mind always travels the road or
by-road of theory, although wavering at the meeting of new
roads. Now Dalton when he saw that the road must be in a
certain direction, did not care to keep by it at every step, and
so surveyed a great extent of territory. It was done with the
quick decision and instinct of the hunter over wild ground.
One only laments that on the first sight of new lands there
was not the poet to burst out into song. It is this want of
poetry, this constant plodding workmanship of the intellect,
that has obtained so few admirers for Dalton, and has allowed
men, whose fame might readily be got from a very few of his
memoirs, to take a position in science and society, which
ought to have been far inferior. Even scientific men have
yielded to the feeling, and, like the world of fashion, have
admired the gayest. But, after all, how few are the scientific
men whose diction gives life to their discoveries. Life is
scarcely apparent till after much nursing.

HI8T0EY OF THE ATOMIC THEORY. 285

The mind never ceases to be strange to us, and if our pic-
tures of men are incorrect, it often arises from our desire to
comprehend thoroughly the whole. This is always diflBcult,
probably impossible, still more so in the case of one so little
demonstrative. But it is not here desired to describe that sub-
stratum of mind common to all men, but those striking features
which stood above the average man, and are the true source
of our interest.

The first thing that we observe in Dalton is clearness of
conception; he knows what he thinks, and can define it.
This is very clear through all his course, every thought is
squared and finished. To this more than anything else I
attribute his first idea of atoms. He was obliged to conceive
of gas, and how could he do it without giving shapes to the
parts ? Gases could not be without parts, they expanded and
contracted, and so the parts became essential to them.

The next thing to observe is directness. He went to his point
rapidly. His experiments are simple, and, although rude, are
exceedingly appropriate. It must, however, be remembered
that although simplicity is at times beautiful, it cannot be
attained in experiment so easily now as then. He pre-
pared the way for more complex methods. Great clearness
of conception often leads the mind to put down its results in
form and figure, giving a mathematical character to them. It
loses the poetical distance by working at the foreground, but
does not forget that the foreground has a beauty and truth of
its own.

The third characteristic is tenacity. His conceptions once
formed seemed never to fade, or were with difficulty eradicated.
This is natural to a mind with strong conceptions. Its own
thoughts become its material, much more than anything said
or done by others, and it prefers to reason from its own data,
being those best known to it. This was remarkably seen in
Dalton.

286 MEMOIR OF DR. DALTON, AND

Fourthly. I would add rapidity of conclusion. This may
arise in various ways. In a mind with weak conceptions or
pictures of things, rapidity may be great, but can be of no
value. In a tenacious mind like Dalton's, rapidity of concep-
tion is a combination of true ideas, so rapidly made that the
steps are not seen clearly by the mind itself, and hence that
inexplicable result which seems at least one of the ways in
which genius is produced.

To understand the truth of these remarks the memoirs must
be read and compared with the times, for Dalton, although he
died but lately, flourished at the birth of true chemistry, and
his work was done when Berzelius was only commencing.

By him laws were more easily treated than facts, and thought
was easier than observation. His mind was one of those which
especially sought laws, desiring to form the link between the
mental and material. He seldom observed without reasoning,
and he had no surplus observation : this made him of an absent
disposition. He seldom reasoned without observing : this
made him an experimenter. But in the movements of his mind,
as of his body, there was a certain rigidity, which he himself
seems to have felt, and for which others have endeavoured to
find causes. One quality Dalton had to a degree almost
unparalleled : the constancy with which he clung to his
occupation of observing and generalizing.

His mind seems to stand before us as an intellectual tool,
constantly planing, drilling, and boring with never ceasing
activity, without any violent fits of haste, and without any
seasons of absolute rest. As far as I know I have indicated
what were the peculiar characteristics of that tool, but there is
no doubt that other circumstances might have brought into
activity a far difierent set of faculties. We see prominently
in him how one portion of the mind was willing to devote
itself to obscurity for the advancement of the others, how the
faculty which reasoned on the " Mind its ideas and affections,"

HISTORY OF THE ATOMIC THEORY. 287

and upon the method by which thought is expressed, after a
very few struggles, gave way to the more active faculties
devoted to physical nature.

Some have objected to such characters by saying that they
result from a want of full development of the faculties, from
a one-sidedness of the mind ; but what man in this short life
can cultivate one faculty highly without depriving the others
of nutriment, or cultivate every faculty equally without stinting
them all?

In Dalton we have found a mind which has shewn itself,
as well in its operations as in its results, to be of the very
highest scientific class.

288 MEMOIR OF DR. DALTON, AND

CHAPTER XIV.

ARRANGEMENT OF THEORIES.

To those who have attended to the history of ideas, it must
always seem a remarkable thing that in early times, among
certain truths, the very culminating point should have been
sometimes attained by one grand bound over all the difficul-
ties of the journey, leaving undescribed all the ruggedness of
the ground passed over. To those who have been born on
this summit, there is the same difficulty in passing down to
the plain, as there is for us to pass upwards : the same blast-
ing of rocks and filling up of morasses. To say that the
history- of the struggle is lost to us does not explain all. In
these three words, already quoted, "measure, weight, and
number," as applied to creation, we see that men had looked
long and carefully on the world, had admired its beauty, and
believed that everything was arranged with scrupulous accu-
racy. The context shows that the fundamental idea was a
moral one, and the reasons we now have were not then in
existence ; but in general terms there is the eminence seen on
which they stood ; we move back towards the plain, or try to
reach the summit, measuring, weighing, and numbering, and
proving the great mountain view to be true to the minutest
particle of matter.

The scientific mind seeks to repeat the order of thought
by which the divine mind arranged the universe ; the artistic
mind sees it completed, and rejoices in its beauty. The
scientific mind has the work of the six days of creation, the
artistic mind lives in the Sabbath of rest. The poetical mind
refuses this class of limitation.

HISTORY OF THE ATOMIC THEORY. 289

These remarks are called forth by the peculiar progress of
some of the early opinions and the difficulties encountered
when experiment began. We may arrange the numerous
theories spoken of in the following manner, seeking the
spirit or fundamental idea of each.

First we have one matter out of which all the others were
made. This in early times was real substantial matter, as water
and earth ; afterwards a dynamical water or earth, or a natural
force corresponding to them or underlying them. Then the
four elements were made the origin of all things ; but conver-
tible. These theories, although under some aspects going
under various heads, may be conveniently put under one
and be called the Allhylic. (aXXoc and iJXi?, interchangeable
elements.)

The next, although allied, claims for itself a separate
place. When there is recognised a universal matter, a prima
materia from which all things are made, and which itself
has no substantial qualities, but is capable of assuming
all, it may be called the prothylic theory, (tt^wtij v\r\, first
element as it was called.)

When matter is made up of indivisible particles, the name
atomic is already appropriately given, (a and to/xoc, uncut.)

When particles are infinitely divisible, it may be useful to
call this theory the dia-tomic. (^la and tojuoc cut through.)

When we find the original matter to be a force only, whether
represented by a number, a point, a line, a geometrical figure,
or a more abstract idea, this is the dynamical theory.

When there are neither forces nor atoms, nor distinct
elements, nor universal and insuperable laws, nor a sub-
stratum of primary matter, the mystic theory seems an appro-
priate name.

In the early atomic theories, the only difference recognised
in atoms is their shape. These theories are mechanical.
Now we recognise many original differences forming elements.
This is a polyhylic atomic theory.

2P

290 MEMOIR OF DR. DALTON, AND

No theory can entirely get rid of Dynamics, but it would
only introduce confusion into the historical account, if we
said more of it than the promoters themselves.

The old theories were after all exceedingly indefinite, not-
withstanding the appearance of exactness. The Daltonian
theory is remarkable chiefly for its idea of quantity. It
defines composition and combination by quantity. It is
mechanical, because it unites pieces of matter in a mason-
like style ; it fits every part and breaks none, but it is not
merely mechanical. Force is required, and this is of a dif-
ferent kind with every species. It is polyhylic. It unites
therefore more qualities than previous theories. There has
never been any progress made in ascertaining in what essen-
tially consists the peculiarity of the forces in each element.
That remains for future inquiry. The inquiry has chiefly
had relation to weight, and for that reason I have called
Dalton's the quantitative atomic theory. Mr. Joule's dis-
coveries in heat, although not purely chemical, have begun to
introduce into chemistry, through physics, forces that can be
exactly calculated other than weight.

I think it of importance that Dalton's theory as adopted ^
by chemists should have a distinct adjective to express it.
The term quantitative atomic connects itself with analysis
which in every case leads us to the use of the theory, although
the most convenient term for general use, by which also we
do honor to the originator, is the Daltonian theory. It re-
presents the mode of discovery by weighing and calculating,
and the greatest fact treated of with regard to atoms, as viewed
by chemists, that they are comparative quantities measurable
by the balance : it represents also the state of chemistry since
the theory was propounded, a wonderfully elaborate collection
of orderly arrangements of bodies distinguished principally
by their quantities. I have left out as unnecessary to this
history such of the characters of atoms as Dalton held more
as hypothetical than theoretical.

HISTORY OF THE ATOMIC THEORY. 291

Those theories, which now appear only as histories, are
not of necessity all extinct ; for some of them a resurrection
day will in all probability arrive, when their forms will be
beautified and their powers exalted. It may be, too, that
in the confusion of transition or the diflBculties of progress,
various inferior appearances may be looked on as the final
triumph, and be hailed by the hasty and the short-sighted,
although seen by the clearer judgment to be mere phantoms
by the way, specimens of the mystic theory. The time may
come when the old theory of the prima materia^ which has
deluded so many, may have a higher existence, and alchemy
again become the " true philosophy." Over this, too, the
dynamical theory may rise, grasping them all, and by giving
clearer ideas of force, thrust into an inferior position both
quantity and matter, and show us, with greater certainty,
the true position of abstract power and of mind.

INDEX.

Absorption of gases by water
Affinity ot gases and vapours

PAOB

46

40

188, 169, 168

BerthoUet's 217

Air, a principle 77

— warm and cold 23

Albertus magnus 103

Alchemy 98, Ac.

Alexandrian school 100

Analysis of volume 251

Anazagoras 81, 86

Anaximander 79

Anaximenes 77

Arabian elements 102, 105

Aristotle 87, 130

Ars sacra 100

Arseniates 274

Artephius Ill

Atmosphere 43

Atoms 89, 125, 169, 230, &c.

Atomic weights 49

Atomic theory, Dalton's 830

Attraction 84

Attractions, elective 104

Aurora BoreaUs a4

Avicenna 106

Bacon, Roger 103, 144

Barometer, fluctuations 20

Baumo 181

Becher 14f

294 INDEX.

Bergman

BerthoUet

Bewley family

Bewley, George

Black

Botticher

Boscovich

Botany

Brewster, Sir D

Boyle

Calces

Character of Dalton

Characteristics, early

Clouds, height of

Colours, vision of

Combining proportions in gases

Condensation of air

Court, presentation at

Cullen

Dalton, decline of

Dalton family

Davy Sir H

Death of Dalton

Des Cartes

Democritus

Diatomic theory

Diogenes of Apollonia

Dynamical theory

Early life

Elements, origin ot

I — one

two

three

four

many

Elliot

Empedocles

Eudiometry

PAGE

143,

148

217

5

10

166

115

136

17

30

119

..

148

61, 269, 283,

, &C.

... 7, 8, 16,

, &c.

22

27

43

34

[, 38

275

144

. ... 251,

277

5

. ... 57, 63,

264

278

129

84,

129

289

77

135

4

. ... 83, 89

, 99

76,

&c.

112

114

77,

&c.

81

. ... 120,

289

167

83

43

INDEX.

295

EvaporatioD

Eye, peculiarity in Dal ton's

Fire, a principle

Pi«cher

Flamel

Fluids, conducting heat

expansion of elastic

Fourcroy

French academy

Funeral of Dalton

Gases absorbed by water

constitution of mixed

diffusion of

. expansion of

structure of

Geber

Geoffroy

Giles's, Samuel, life of Dalton

Gough

Glauber

Grammar, English

Habits

Hai Ebn Yokdan

Heat by condensation and rarefaction of air

.... power of fluids to conduct

Helmont, Van

Henry's, Dr. W., letter to Mr. Babbage ..

Heraclitus

Herschel, Sir John

Higgins, Bryan

Higgins, W

Homeomeria

Hope, Dr

Hindoo atomic theory

Hooke

Intellectual character

Joule

31, 36

, 40

• -

29

...

79

.

216

HI,

112

.

82

...

87

158

263.

268

280

45

.

36

... 37

, 46

34, 3«

, 41

...

47

105

...

123

. ...

62

...

10

. ...

119

...

34

27, 53

» 71

...

102

.

34

...

32

. 77,

142

.

269

... 79

, 92

. ...

80

...

167

175

... 82

, 93

.

33

95,

101

. ...

127

269,

283

... 33

, 38

296 INDEX.

Kirwan

Kircher, Athanasius

Lectures

Lectures in London

Lemery

Letters of Dalton

Leucippus

Lucretius, Atomic Theory of
Liilly, Raymund

Mathematical elements ..

Matter, Lully's

■ Hooke's

everything

ideas of ,

from the soul

Mayow

Morals, as a chemical agent...

Mehung

Memoirs, list of Dalton's ...

Metals, alchemical

Meteorological Essays

Morveau

Mystic Theory

New College

New System of Chemistry ...

Newton

Norton

Oxides

Oxford Title

Owen, Robert

Palissy

Paracelsus

Paris visit

Parmenides

Pension

Phlogiston

Phosphates

PAGE

...

158

31

...

14

...

56

...

122

... 55, &c.

84, 89

...

88

...

108

.

. 80

...

108

128

..

87

.

, 74

...

89

123

..

105

107

...

253

105,

113

..

19

136,

157

••

101

...

18

248,

267

125,

134

...

113

143,

148

...

268

27,

253

...

114

114

265

...

83

...

272

142,

14S

...

274

INDEX. 297

PAOB

Photograph 27»

Plato 84

Playfair 88

Polyhylic theory 289

Portrait 61

Pressure — in gases 87

Proportion, B. Higgins 171

W. Higgios 177

Prothylic theory 389

Proust 220

Prima materia 110, 118

Putrefaction 102, 107

Pythagoras 80

Quinta essentia 107

Rtun and dew

Ransome, J. A

Rarefaction of air

Reasoning, rapidity of

Religion, as a chemical agent

Repulsion

Richter

Ripley

Royal Society

Rumford, Count

Salt, alchem

Salts, bulk in water

Saturation

School advertisements

Shunck, E

Sea, water that flows into

Sennertus

Shaw

Social life

Spiritual origin of matter

Springs

Society, Literary and Philosophical

Stahl'

Statue of Dalton

Steam

2Q

31

...

29

.. 34

I, 38

23,

286

...

105

...

84

...

186

...

113

265

••

82

...

114

.

273

...

137

13

...

63

...

81

130

...

126

61

100,

135

81

33,

, 51

..

142

275,

281

36,

, 39

298

INDEX.

Stoechiometry

Stoics ... '

Strutt, Mr ,

Style

Substance, immaterial
Sugar analysis

Thales

Theories, classified ..

daring

Thomson

Urbiger

Valentine, Basil

Vapour

condensation of ...

Water, a principle ... ,

maximum density

Watson, Bishop

Wenzel

Wilson, Dr. George ... ,
Woolley's life of Dalton...

Yle

Zeno, of Elea

Zosimus

PAGE

106, 187

... 87

264

19, 20

110

. 273

. 76
288

.. 23
182

.. 112

.. 107
36, 89
.. 23

76

,. 33

131

.. 160

80

Preface

.. 104

83
... 101

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Geological Society The Quarterly Journal of the Geological Society,

Vol. XL, Part 4, Nov. 1, 1855.

Ditto Ditto, Vol. XIL, Parts 1 and 2, Nos. 45 and 46.

The Author An Essay on Meteorites. By R. P. Greg, Esq.

Library Committee, Man-
chester Corporation... Third Annual Report of the Working of the Man-
chester Free Library.

Commissioners of
Patents Alphabetical Index of Patents of Inventions.

Ditto Ditto of Patents Applied for and Patents Granted.

Ditto Reference Index of Patents of Inventions.

Ditto Appendix to Reference Index.

Ditto Subject Matter Index of Patents of Inventions,

Parts 1 and 2.

Academie de Dijon Memoires de I'Academie des Sciences.

Ditto Memoires de I'Academie des Sciences Arts et

Belles Lettres de Dijon, 1828-29-30-31-32-
34-36-43-44-45-56-47-48-49-50-51-52-53-54-
55, to Tome IV., 2nd ser. inclus.

wrrn a list of the donors. 303

donous. donations,

Royal Saxon Society op

SciBNCEd Berichted.Philolog. Histor. Classe, 1849, I. toV.

Ditto Ditto ditto 1850, I. to IV.

Ditto Ditto ditto 1851, I. to V.

Ditto Ditto ditto 1862, I. to IV.

Ditto Ditto ditto 1853, I. to V.

Ditto Ditto ditto 1854, I. to VI.

Ditto Ditto ditto 1855, I. to II.

Ditto Abhand. d. Math. Phya. Classe L and II., B.

Ditto Drobisch, Nachtrage ueber Musikal. Tonverhalt-

nisse.

Ditto Berichte d. Math. Phys., Classe 1849—1855.

Ditto Abhand. d. Philolog. Histor., Classe 1850.

Ditto Roscher zur Geschichte d. Engl, Volkswirthschafts-

lebre 1851, Nachtrage 1852.

Ditto Moromsen, Polemii Sylvii Laterculas, 1853.

Ditto Ditto, Volusii Maeciani Distributio, 1853.

Ditto Droysen, Everard Windeck, 1853.

Ditto Ditto, Kaiser Karls V., Lande, 1854, and V.

Wietersheira Gedachtnisslehre, 1854.
Academy of Sciences
OF THE Institute of
Bologna Memorie della Academia delle Scienze dell' Isti-

tutodi Bologna, Tom I., II., III., IV., and V.
Professor Sedgwick On the British Palaeozoic Rocks and Fossils, with.

Plates. By Sedgwick and McCoy.
Mr. Routledge Letter on the Operation of the Smoke Nuisance

Act. By C.W. Williams, 3 copies.
Administration des
Mines de Rdssib Compte Rendu Annuel par le Directeur de 1' Ob-

senratoire Physique Central. A. T. Kufpfer,

St. Petersburgh, 1854 and 1855.
The Author Useful Information for Engineers. By W. Fair.

BAIRN, F.R.S., &€., 1856.
Chemical Society, Lon-
don Quarterly Journal of the Chemical Socieiy of Lon-
don, Vol. VIII., No. 4, and Vol. IX., Nos. 1 and 2.
Institoto, LoMBAROO Giomale dell I. R. Istituto Lombardo di Scienze

Lettere cd Arti. Bibliotheca Italiana, Nnove

Serie, Vols. I., II., IIL. IV., V., VL, VU.,

1847-55.
Tub Author ...Introductory Lecture on the Harmony of Theory

and Practice in Mechanics. By W. C. M.

Ramkine, CE., &c., University, Glasgow.
Zoological Botanical

Society, Vienna Verhandlungen dcs Zoologisch botaniscben rereios

in Wien, Bd. I., Ill . IV , and V., 1, 2. 3.

304 DONATIONS RECEIVED SINCE LAST PUBLICATION,

donors. donations.

Imperial Geological
Institdtion, Vienna ...Jalirbuch der K. K. Geologischen Reichsanstalt,

Vol. L

The Apthor.. Recherches sui* la Vegetation. Par M. Ville.

LiNNBAN Society Journal of the Proceedings of the Linnean Society,

Vol. I., Nos. 1, 2.
The Author Narrative, &c., of the Association for obtaining a

Uniform Decimal System. By James Yates,

Esq.
Society of Natural
Sciences, Cherbourg ..Memoires de la Societe des Sciences Naturelles de

Cherbourg, Tome L and II., 1853-4.
Ditto Notice a' 1' anciennes fabriques de draps, de Cher-
bourg. Par A. le Jolis, de Cherbourg, 1854.
Ditto... Notice sur 1' origine et 1' etablissement de la Foire

St. Clair de Querqueville. Par M. A. le

Jolis, 1865.
Ditto ...Observations sur les Ulex des environs de Cher-
bourg. Par A. le Jolis, 1858.
Ditto Examen des especes confondues sous le nom de

laminaria digitata. Auct. par M. A. le Jolts,

1855.
Royal Asiatic SociETY...Transactions of the Royal Asiatic Society, Vol. III.,

Parts 1, 2, and 3, with Appendix.
Ditto Journal of the Royal Asiatic Society, Nos. 13 to

18, and Vols. X. to XVI., Part 2 inclusive.
Ditto Descriptive Catalogue of the Historical Manuscripts

in the Arabic and Persian Languages, in the

Library of the Royal Asiatic Society.

Ditto Essay on the Architecture of the Hindoos.

Ditto Maps, Nos. 1 and 2, Vestiges of Assyria, and Map

of Central Assyria. By Felix Jones.
The Author Picture of a Manufacturing District. By E.

Potter, F.R.S.
Ditto On Rubian and its Products of Decomposition,

Part 8. By E. Schunck, Ph.D., F.R. S., &c.
Zoological Society, Lon-
don Proceedings of the Zoological Society of London,

5 vols., 1850-56.

The Author A Lecture on Strikes. ByJ.A.NicHOLLS,F.R.A.S.

Ditto A Natural History of Ferns, Parts 1 to 20 inclus.

By A. J. Lowe, F. R. A. S. and E-, Nottingham .
Ditto The Present Crisis in Administrative Reform. By

J. P. Gassiot.
Linnean Society of Nor-
mandy Memoires de la Societc Linneene du Calvados,

1824-25. 2 vols., and Atlas.

WITH A LIST OF THE DONORS. 306

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mandy Memoires de la Societe Linneeoe de Nonnaodie,

IBS'! lo 1853. 4 vols., ditto.

Ditto ...Seance Publiqae, ltt33 and 1836.

The Author Wreck of tbe Rotbmy Castle. By J. Adsiiead,

Esq.

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Ditto Our Present Gaol System. By ditto.

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Imperial Academy of
Metz Memoires de TAcademie Imperiale de Metz, 1840-

46. 1848-49-50, 1853-54-55. Total, 14 vols.
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Copenhagen Memoires de la Societe des Antiquaires, Copen-

hague, 1845-49, V^ol. I., 1852.
The Author Aus der Hagia Sophia. Von Padlus Cassell,

Secretar der Erf urter Academie.
NaturalHistory Society,

Geneva - Memoires de la Societfe de Physique et d'Histoire

Naturelle de Geneve, Tome XIV., Partie 1,
1855.
NaturalHistory Society,

Bonn Verhandlungen des Natnrhistorischen Vereins der

Preussischen Rheinlande und Westphalens,
1855, 1856.

Ditto Sitzungsberichte und Correspondenz Blatt, 1855,

1856.
Royal Cornwall Poly-
technic Society Twenty-third Annual Report of the Royal Corn-
wall Polytechnic Society.
Leopold Caroline
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ralists, Breslau Acta Academiae Naturae Curiosomm, Vol. XXV.,

Part 1, 1855.
Royal Academy op
Sciences and Belles

Lettres, Naples Rendiconto della SocietaRealeBorbonica Academia

delle Scienze, Anno IV., 1855.

Ditto Eruzioni Vesuviane, del 1860, E 1855.

Bavarian Academy of

Sciences Abhandlungen d. Akad. d. Wissenschaflen histor.

u. Philos. Inhalts B. I-X., 1763-1776.

Ditto Neue Philos. Abhandlungen, I-VII., 1778-97.

Ditto...., Physik. Abhand , 1-2, 1803-6.

Ditto Berichte ueber d. Arbeiten d. Math. Phys. Clawe,

1-4, 1807-11.

Ditto Gelehrte Anzeigen. B. 38-40, 41.

2B

306 DONATIONS RECEIYED SINCE LAST PUBLICATION, &c.

donobs. donations.

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Sciences Bulletin pro 1847-63.

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Ditto Abhand. Math. Phys., 1829-1864.

Ditto Pettenkofer. Chemie.

Ditto Buchner. Antheil.

Ditto Vogel. Chemisch.Laboratorium.

Ditto Vogel. Chemismus.

Ditto Kuhn. Clima.

Ditto Hermann. Bewegung d. Bevolkerung.

Ditto Gliederung. Ditto.

Ditto Lamont. Denkrede.

Ditto Abhandlungen der Philos. Philolog. Classe, Vol.

VII,, abth. 3.

Ditto Annalen der Sternwarte, Vols. VII., VIII.

Ditto Almanach, 1865.

Imperial Academy of

Rouen Precis Analytique de 1' Academie de Rouen, 1864-55.

Yorkshire Geological

Society Report of the Proceedings of the Geological and

Polytechnic Society of the West Riding of
Yorkshire, 1865.
Leeds Literary and

Philosophical SociETY.Thirty-sixth Report of the Council of the Leeds
Philosophical and Literary Society, 1855-56.
Geographical Society ...Proceedings. Anniversary Address of the Royal

Geographical Society, 1856.

Royal Institution Notices of the Meetings of the Members of the

Royal Institution of Great Britain. Part 6.
July, 1856, to July, 1856.
Royal Society of Edin-
burgh Transactions of the Royal Society of Edinburgh.

Vol. XXL, part 3, 1855-56.

Ditto Proceedings of ditto session 1855-66.

Royal Society of Stock-
holm Proceedings of the Royal Society of Stockholm,

1844 to 1865 inclusive, 12 vols.
Ditto Transactions of ditto 1844 to 1854 in-

clusive, 11 vols.
Administration of the
Imperial Mines, Russia. Anna?es de 1' Obsei*vatoire Physique Central de
Russie, 1851-52-53. Published 1853-64-55.
5 volumes. (St. Petersburgh.)

THE COUNCIL

07 THB

f itoarg ani |feil0sopfeital Sm\^ at '^mitsttx.

1866^7.

WILLIAM FAIRBAIRN, F.R.S., Inst. Nat. Sc, Paris Corresp.

Vicc-^prc0flientfl.

JAMES PRESCOTT JOULE, F.R.S., &c.
JOSEPH CHEESEBOROUGH DYER.
THOMAS HOPKINS.
EDWARD WILLIAM BINNEY, F.R.S., F.G.S.

ROBERT ANGUS SMITH, Ph.D., F.C.S.
EDWARD SCHUNCK, Ph.D., F.R.S.

Cteaauvcr.
HENRY M. ORMEROD.

Eibramn.
CHARLES FREDERIC EKMAN.

®f tf)c Council.

RICHARD ROBERTS, M.Inst.C.E.

HENRY BOWMAN.

JAMES WOOLLEY.

PETER SPENCE.

REV. HENRY HALFORD JONES, F.B.A.S.

PROFESSOR R. C. CHRISTIE, M.A.

ALPUABETICAL LIST OF THE MEMBERS

f fet Perarj ani |pp0S0piiraI S0mtB jof Stantfewto,

1866-67.

DATE OF BLBCnOX.

Ralph F. Ainsworth, M.D April 30th, 1839

James Allan, Ph.D., MA January 24 th, 1864

W. H. Ash April 17th, 1849

Thomas Ashton, Hyde August 11th, 1887

John Atkinson January 27th, 1840

Joseph Adshead April 29th, 1856

Robert Barbour January 2drd, 1824

Henry Bernoulli Barlow January 27th, 1862

Joseph Barratt April 19th, 1842

Rev. R. Bassnett, A.M April 17th, 1849

John F. Bateman, M.Inst.C.E., F.G.S., &c January 21st, 1840

Thomas Bazley January 2Cth, 1847

Thomas Sebastian Bazley, B.A April 19th, 1868

William Bell January 26th, 1847

James Bevan January 23rd, 1844

Edward William Binney, F.R.S.,F.G.S January 25th, 1842

Alfred Binyon January 26th, 1888

Richard Birley April 18th, 1834

James Black, M.D., F.G.S April 30th, 1839

John BlackwalU F.L.S January 26th, 1821

Henry Bowman October 29th, 1839

Eddowes Bowman, M.A January 23rd, 1865

Charles Beyer January 24th, 1854

William Brockbank April 17th, 1866

Edward Brooke April 80th, 1824

W. C. Brooks, M.A January 23rd, 1844

Frederick Broughton April 17th, 1865

Henry Browne, M.B January 27th, 1846

Laurence Buchan NoTember 1st, 1810

310 ALPHABETICAL LIST OF THE MEMBERS.

DATE OF ELECTION.

John Burd January 27th, 1846

Henry Bury April 19th, 1863

William Callender, jun January 24th, 1854

Frederick Grace Calvert, M.R.A.T January 26th, 1847

John Young Caw, F.S.A., F.R.S.L April 15th, 1841

Charles E. Cawley, C.E January 23rd, 1855

David Chadwick April 20th, 1852

Henry Charlewood January 24th, 1832

Richard Copley Christie, M.A., Owens College April 18th, 1864

Charles Clay, M.D April 15th, 1841

Charles Cleminshaw , April 29th, 1851

Samuel Clift April 19th, 1853

Thomas Cooke April 12th, 1838

Edward Corhett January 25th, 1853

Samuel Cottam January 25th, 1863

Samuel Crompton April 29th, 1851

James Crossley January 22nd, 1839

Joseph S. Crowther January 25th, 1848

Richard S. CuUey, C.E January 24th, 1854

Matthew Curtis April 18th, 1843

John Dale February 7th, 1854

John Benjamin Dancer, F.R.A.S April 19th, 1842

Robert Dukinfield Darbishire April 19th, 1853

David Reynolds Davies January 24th, 1854

James Joseph Dean November 15th, 1842

William L. Dickinson January 23rd, 1855

Joseph Cheeseborough Dyer April 24th, 1818

Frederick Nathaniel Dyer April 30th, 1860

The Right Hon. the Earl of EUesmere, F.R.S., &c April 15th, 1841

Charles Ellis January 24, 1854

Charles Frederic Ekman April 29th, 1856

George Fairbairn January 25th, 1853

Thomas Fairbairn April 30th, 1860

W. Fairbairn, F.RS., Inst. Nat. Sc, Par. Corresp October 29th, 1824

W. A. Fairbairn October 30th, 1849

David Gibson Fleming January 25th, 1852

Richard Flint October 31st, 1818

Benjamin Fothergill , January 23rd, 1855

H. R. ForreBt April 29th, 1856

ALPHABETICAL LIST OF THE MEMBEBS. 311

DATS or sLBonoir.

E. Frankland, Ph.D., F.R.S.» Oweni College April 20tb. 1861

Alfred Fryer January 2'lth, 1864

Rev. William Ga»kell, M.A January 21rt, 1840

Samuel Giles April 20th, 1886

John Gould April 20th, 1847

John Graham August 11th, 1837

Robert Hyde Greg, F.G.S January 24th, 1817

Robert Philips Greg October 30th, 1849

John Clowes Grundy January 26th, 1848

Richard Hampson January 23rd, 1844

John Hawkshaw, F.R.S., F.G.S., and M. Inst. C.E January 22nd, 1839

William Charles Henry, M.D., F.R.S October 31st, 1828

John Hetherington January 24th, 1854

Sir Benjamin Heywood, Bart., F.R.S January 27th, 1815

James Heywood, M.P., F.R.S., and G.S AprU 26th, 1833

James Higgin April 29th, 1861

James Higgins April 29th, 1846

Peter Higson October 31st, 1848

John Hobson January 22nd, 1839

E. Hodgkinson, F.R.S., M.R.LA., F.G.S., &c January 2l8t, 1820

George Holcroft January 24th, 1854

Isaac Holden January 23rd, 1855

James Piatt Holden January 27th, 1846

Thomas Hopkins January 18th, 1823

Henry Houldsworth January 23rd, 1824

William Jennings Hoyle February 7th, 1854

John Jesse, F.R.S., R.A.S., and L.S January 24th, 1823

Richard Johnson April 30th, 1850

William Johnson January 22nd, 1866

Rev. Henry Halford Jonea, F.R.A.S January 22nd, 1856

Joseph Jordan October 19th, 1821

B. St. J. B. Joule April 18th, 1848

James Prescott Joule, F.R.S., &c January 25th, 1842

William Joynson January 27th, 1846

Samuel Kay January 24th, 1848

John Lawson Kennedy January 27th, 1858

James Kershaw, jun January 24th, 1854

Richard Lane April 26th, 1822

3 1 2 ALPHABETICAL LIST OF THE MEMBERS.

DATE or ELECTION,

William Langton , April 30tb, 1830

Joseph Leese, jun. .. April 30th, 1850

Thomas Taylor Lingard January 22nd, 1856

Thomas Littler January 27th, 1825

Joseph Lockett October29th, 1839

Benjamin Love April 19th, 1842

Isaac Waithman Long, F.R.A.S January 27th, 1852

George CliiFe Lowe January 24th, 1854

Edward Lund April 30th, 1850

George T. Lund January 23rd, 1865

William Tudor Mabley October 30th, 1855

James M'Connel October 30th, 1829

William M'Connel April 17th, 1838

Alexander M'Dougall April 30th, 1844

John Macfarlane January 24th, 1823

Edward William Makinson, MA October 20th, 1846

The Right Rev. the Lord Bishop of Manchester, D.D., F. R.S.,

F.G.S April 17th, 1849

Robert Manners Mann January 27th, 1846

Thomas Mellor January 26th, 1842

William Mellor January 27th, 1837

John Moore, F.L.S January 27th, 1815

David Morris January 23rd, 1849

AlfredNeild January 25th, 1848

William Neild April 26th, 1822

James Emanuel Nelson January 27th, 1852

Thomas Henry Nevill February 7th, 1854

John Ashton NichoUs, F.R.A.S January 21s(, 1845

William Nicholson January 26th, 1827

Edward Byron Noden October 31st, 1854

Henry Mere Ormerod April 30th, 1844

George Parr April 30th, 1844

John Parry April 26th, 1833

George Peel, M.Inst.C.E April 16th, 1841

Henry Davis Pochin January 24th, 1854

John Ramsbottom February 7th, 1854

Joseph Atkinson Ransome, F.R.C.S April 29th, 1836

Thomas Ransome r January 26th, 1847

ALPHABETICAL LIST OF THE MEMBERS. 313

DATE OF BLBCriON.

Richard Roberts, M.In8t.C.E January 18th, 1823

Samuel Robinson January 2flth, 1822

Alan Royle January 25lh, 1842

Samuel Salt Aprill 8th, 1848

Archibald Sandeman, M.A., Owens College April 29th, 1851

Michael Satterthwaite, M.D January 20th, 1847

Edward Schuuck, Ph.D., F.R.S January 2ath, 1842

Alexander J. Scott, M. A., Principal, Owens College February 7th, 18d4

Edmund Hamilton Sharp January 23rd, 1850

John Shultleworth October .S 0th, 1835

Joseph Sidebotham April 20th, 1852

George S. Fereday Smith, M.A., F.G.S January 20th, 1838

Robert Angus Smith, Ph.D., F.C.S April 29th, 1845

Peter Spence April 29th, 1851

Thomas Standring January 27th, 1862

Edward Stephens, M.D January 24th, 1834

James Stephens April 20th, 1847

Robert Stuart January 2l8t, 1814

John Edward Taylor January 22nd, 1836

David Thorn April 20th, 1852

James Thompson April 18th, 1864

James Aspinal Turner April 29th, 1886

Thomas Turner, F.R.C.S April 19th, 1821

Absalom Watkin January 24th, 1823

Joseph Whitworth January 22nd, 1832

Samuel Walker Williamson April 19th, 1853

William Crawford Williamson, F.R.S., Owens College April 20th, 1851

George Bancroft Withington January 21 st, 1861

William Rayner Wood January 22nd, 1839

Alonza B. Woodcock October 30th, 1855

George Woodhead April 21st, 1846

Edward Woods April :JOth, 1839

James Woolley November 15th, 1842

Robert Worthington, F.R.A.S April 28th, 1810

2 S

HONORARY MEMBERS.

Bev. William T\imer, Manchester.

Sir Oswald Mosley, Bart., HoUetton EaU.

Bey. Adam Sedgwick, M.A., F.B.S., Hon. M.B.I.A., &o., Cambridffs.

General Sir Thomas Makdougall Brisbane, Bart., F.B.Sm Hon. M.B.I.A., Instit.

Nat. Sc, Paris Corresp., &c., Makerstounj Kel$o.
Bev. William Venablee Vernon Harcourt, M.A., F.B.S., Hon. M.B.I.A., F.G.8.,

York.
Bey. WiUiam WheweU, B.D., F.E.8., Hon. M.E.I.A., F.E.A.S., &c., Cambridge.
Sir William Hamilton, Bart., Dublin.
Baron Yon Liebig, Munehm,
Eilert Mitschorlich, Berlin.
Sir John Frederick William Herschel, Bart., D.C.L., FJt.S. L. & E., &c., &c.,

Instit. Nat. Sc, Paris Corresp.
Michael Faraday, Esq., D.C.L., Hon. Mem. B.8. Ed., Instit. Nat. Paris Socius.
George Biddell Airy, Esq., M.A., D.C.L., F.E.A.8., F.B.8., &c., &c., RoycU

Observatory.
Sir David Brewster, F.B.S. L. & £., Instit. So. Paris Sooios, Hon. M.B.I.A.,

F.G.8., F.R.A.8., &c., St. Andrew's.
Very Bev. George Peacock, D.D., F.R.8., F.G.S., F.B.A.S., My.
Baron Alexander Von Humboldt, Berlin.
Peter Barlow, Esq., F.B.S., F.B.A.S., Hon. M.P.C.S., Instit. Nat. So., Paria

Corresp., Woolunoh.
Bev. Henry Moseley, M.A., F.B.8., Wandsworth.
Louis Agassiz, Cambridge^ Massaehussets.

lieut.-Colonel Edward Sabine, R.A., F.R.8.V.P., F.B,A.8., &c.
Jean Baptiste Dumas, Farts.
Sir Boderick Impey Murchison, G.O. So. S., M.A., F.G.S., Hon. M.B.S. Ed.,

B.I.A., &©., &c.
Richard Owen, Esq., M.D., L.L.D., F.B.S., Hon. M B.B. Ed., Instit. Nat. Sc.,

Paris Corresp., &c., &c.

316 CORRESPONDING MEMBERS.

«
John Couch Adams, Esq.. F.R.S, F.R.A.S., &c., Cambridge.

TT. J. J. Le Verrier, Farts.

J. R. Hind, Esq., Eegenfs Park.

Rev. Joseph Bosworth, L.L.D., F.S.A., F.R.S., &c.

Robert Rawson, Esq., Portsmouth.

Bennet Woodcroft, Professor, University College.

William Thompson, Professor, University, Glasgow.

Lyon Playfair, C.B., F.R.S., &c., Department of Science and Art, Marlborough

Souse.
George Gabriel Stokes, M.A., &c., &c., Cambridge.

Rev. Thomas Penyngton Kirkman, M.A., &c., Croft Rectory, near Warnngton.
William Hopkins, Esq., F.R.S., Pres. Geo. Soc, &c., Cambridge.
JohnHartnup, F.R.A.S., Observatory, Liverpool.
General M. A. Morin, Mem. Instit. France, &c., Paris.
Rev. John James Tayler, B.A., Principal of Manchester New College, London.
General Poncelet, Mem. Instit. France, &c., Paris.

CORRESPONDING MEMBERS.

Rev. John Kenrick, M.A., York.

Benjamin Dockray, Esq., Lancaster.

Jonathan Otley, Esq., Keswick.

Rev. Robert Harley, Briglwuse, near Huddersjield.

William Thaddeus Harris, Esq., Cambridge, Massachussets.

Peter Pincoffs, M.D., Dresden.

Henry Hough Watson, Esq., Bolton.

John Mercer, Oakenshatv.

M. Girardin, Eouen.

T. T. Wilkinson, F.R.A.S., &c., Burnley.

T. 80AVLER AND SONS, PRINTERS, MANCHESTER.