Memoir Joseph von Fraunhofer

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THE

1

JOURNAL OF SCIENCE,

EXHIBITING

A VIEW OP THE PROGRESS OF DISCOVERY

IN- SAT URAL PHII.OSOPHY, CHEMI8TH.Y, HIKERALOOT^ GEOLOGY, BOTANY,
ZOOLOGY, COMPARATIVE ANATOMY, PRACTICAL MECHANICS, GCOOBAPH7,

!

XAVIGATION^ STATISTICS, ANTIQUITIES, AKD THE FIKE AND USErUt ARTS-

CONDUCTED BY

DAVID BREWSTER, LL.D

F.R.S. LONO. SEC. B.S. £DIN. F.S.S.A.

I -4

CORRF^SPONDINQ MEMBEH QW THE INSTITUTE OP FRANCE ; HONORAEV MEMBER OF THE BOTfA^

lEtSH ACADEMY ; MEMBER OF THK ROYAL SWBPISH ACADKMV OW SCIENCES;

AND OF THE ROYAL SOCIETY OF 6CXENCKS OP DKNIUARK, &C. ifec*

^p^

VOL. VII.

I

APRIL—OCTOBER.

JOHN THOMSON, EDINBURGH:
AND T. CADELLs LONDON.

M.DCCC.XXVII.

CONTENTS

OF THE

EDINBURGH JOURNAL OF SCIENCE.

1 I

No. XIII.

«l«

Art. I. Memoir of the Life of M, Le Chevalteii Feauxhofer, the Cek'
brated Improver of the Achromatic Telescope, and Member of the Aca*
demy of Sciences at Munich^ "* m

IL Uetiiarks on Mount Vesuvius* Communicated by a CojiiiespondenT,
III* On Mesole, By Wili^iam HaidikgEr, Esq. F.R. S-E,&c- Com*
municated by the Author, - •

IV. Some Account of a Society lately established in Germanyj of which

the object is to send out Botanical Collectors to the most interesting
parts of Europe; together with a recommendation to the Naturalists of
other Countries, and especially those of Great Britain^ to unite with it,
Commtmicated by W* Jackson Hooker, LL, D. F. R< S. F* L. S-
F, A, S. and Regius Professor of Botany in the University of Glasgow,

V. Views of the Process in Nature by which, under particular circumstances,

vegetables grow on the bodies of Living Animals. Bf Dr Samuel L,
MitCHiLL of New Yorkj F. R. S» E* With remarks by a Correspon-
dent, - * • -

VL On the Dew- Point Hygrometer formerly described in this Journal, voL iv*
p. 127- By Mr Joiik Foggo, Junr. Communicated by the Author,
VII* Description of a Plant of the order of Guttiferas^ which Dr Roxburgh
called Garcinia pedunculata. By Francis HamijuTOn, M. D. F-U. S,
and F* A* S. Lond. and Edin. Communicated by the Author.
VIIL Contributions to Physical Geography,

1* Description of the Cavern of Adelsberg in Carniola,

2* Account of the Subterraneous Sounds heard at Nakous in Arabia

Petraea. By M, See t ZEN,
3* Account of the Granite Quarries at Assuan. By the Honourable
C- L- Irby, and James Mangles, Esq. Commanders in the Navy,
4* Account of Hot Springs and Volcanic Appearances in the Himalaya

Mountains, • , *

B* Account of the Brahma Kund^ By Captain Bedford,
6» Notice of the Fhoonga Caves in Junk Ceylon- By Captain Low,
7* Notice of the Cavern of the Sagat Rock, upon the Sagat Strait of

the Sanloon or main river of Martaban,
8. Account of the Floating Island of Newbury Port, By Mr A 3103
Fettingall Jun. . - -

IX. Notice respecting the Vanderon Monkey, or the Guenon A Jace pour-
* pre of Buffom By Francis Hamilton, M. D* F. R* S. and F* A. S.

Lond- and Edin. Communicated by the Author,

X. Description of a New Safety.Tube for Chemical Apparatus* By James

King, Esq. Communicated by the Author, *

a

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4.-1 — _.^^-

THE

EDINBURGH

JOURNAL OF SCIENCE

Aet. l.^^Menwir tf the Life of M, Le Chevalier Fravn-
HOFERy the Celebrated Improver of the Achromatic Tele-
scope, and Member of the Academy of Sciences at Munich.

r

*•

Or all the losses which science is occasionally called to sus-
tain, there is none which she so deeply deplores as that of an
original and inventive genius, cut off in the maturity of in-
tellect, and in the blaze of reputation. There is an epoch in
the career of a man of genuine talent when he embellishes and
extends every subject over which he throws the mantle of his
genius. Imbued with the spirit of original research, and fa-
miliar with the processes of invention and discovery, his mind
teems with new ideas, which spring up around hira in rapid
and profuse succession. Inventions incompleted, ideas un-
developed, and speculations immatured, amuse and occupy
the intervals of elaborate inquiry, and he often sees before
him in dim array a long train of discoveries which time and
health alone are necessary to realize. The blight of early ge-
nius that has put forth its buds of promise, or the stroke
which severs from us the hoary sage when he has ceased to
instruct and adorn his generation, are events which are felt
with a moderated grief, and throughout a narrow range of
sympathy -^ but the blow which strikes down the man of genius
in his prime, and in the very heart of his gigantic conceptions,
is felt with all the bitterness of sorrow, and is propagated
far beyond the circle on which it falls. When a pillar is torn
from the temple of science, it must needs convulse the whole

VOL. VTI. NO. I. JULY 1827. A

S Memoir of the Life of M, Fraunhqfer.

of its fabric, and draw the voice of sorrow from its inmost re-
cesses. To those who have not studied the writings, or
used the instruments of the illustrious subject of this memoir,
these observations may seem extravagant and inapplicable;
but there is not a philosopher in Europe who will not ac-
knowledge their truth, as well as their application ; and there
is not a practical astronomer within its widest boundaries that
has not felt the tide of grief for the loss of Fraunhofer flow-
ing within his own circle. ^*

Joseph Fraunhofer was born at Straubing, in Bavaria, on
the 6th March 1787. His occupations in the workshop of
his father prevented him from giving a regular attendance at
the public schools. At the early age of eleven he was de-
prived of both his parents, and the person to whose charge he
was entrusted destined him for the profession of a turner ; but
his weak frame being ill suited to such an occupation, he was
apprenticed to M. Weichselberger, manufacturer and polisher
of glass at Munich. Being too poor to pay any thing to his
master, he was taken on the condition that he should work for
him six years without any wages.

At Munich Fraunhofer frequented the Sunday school, but
as his attendance was irregular, it was a long time before he

to write or to count. In 1801, in the second year of
his apprenticeship, an accidental circumstance gave a new
turn to his fortune. Two houses having tumbled down sud-
denly, Fraunhofer, who lived in one of them, was buried un-
der its ruins ; but while others perished, he fortunately occu-
pied a position to which it was considered practicable to open
a passage. While this excavation was going on, the King
Maximilian often came to the spot to encourage the workmen
and the young prisoner ; and it was not till after a labour of
four hours that they were able to extricate him from his peri-
lous situation. His majesty gave directions that his wounds
should be carefully attended to, and as soon as he had recover-
ed, he was sent for to the palace to give an account of the pe-
culiarities of his situation during the accident, and of the feel-
ings with which he was actuated. On this occasion his sove-
reign presented him with eighteen ducats, and promised to
befriend him in case of need.

Memoir of the Life of M. Fraimlictfer. . 3

Mr Counsellor Utzschneider, afterwards his partner in the
great optical establishment at Benedictbauernj took him also
under his protection, and occasionally saw him. Fraunhofer,
full of joy, showed him the king'^s present, and communicated
to him his plans, and the way in which he proposed to spend
the money. He ordered a machine to be made for polishing
glass, and he employed himself on Sundays in grinding and
finishing optical lenses. He was, however, often baffled in
his schemes, as he had no theoretical and mathematical know*,
ledge. In this situation M. Utzschneider gave him the ma-
thematical treatises of Klemm and Tenger, and pointed out
to him several books on optics. Fraunhofer soon saw, that,
without some knowledge of pure mathematics, it was difficult
to make great progress in optics, and he therefore made them
one of the branches of his studies.

When his master saw him occupied with books, he pro-
hibited him from using them, and other persons whom he con-
sulted did not encourage him to undertake the study of ma-
thematics and optics without assistance, and at a time when
he was scarcely able to write. These obstructions, however,
served only to redouble the efforts of our author ; and though
he had no window in his sleeping chamber, and was prohibit-
ed from tislng a light, yet he acquired a considerable know-
ledge of mathematics and optics, and endeavoured to apply
them to his own schemes.

Tn order to obtain more leisure, he employed the remainder
of the royal present in buying up the last six months of his
apprenticeship ; and that he might gain some money for his
optical experiments, he engraved visiting cards without ever
having been taught the art of engraving. Unfortunately,
however, the war which then desolated Europe put an end to
the sale of his cards, and left him in greater exigencies f han
before.

Noth withstanding the kind assurances of protection which
the king had given him, Fraunhofer had not courage to re-
quest it, and he was therefore compelled to devote himself to
the grinding and polishing of glasses, still continuing to de-
vote his Sundays to the study of the mathematics.

Mr Utzschneider was at this time seldopi at Munich, and

4 , Memoir of the Life of M. Fraunhqfer-

could do nothing for our young artist ; but he recommended
him to a professor of the name of Schiegg, well versed in ma-
thematics and natural philosophy, who paid frequent visits to
Fraunhofer.

About this time was formed the celebrated establishment at
Benedictbaucrn, near Munich, by MM. Reichenbach, Utz-
schneidcr, and Liebherr, and in August 1804, they began
the manufacture of optical and mathematical instruments,
which were divided by the new machine of Reichenbach and
Liebherr. The whole of the ap|)&ratus was made there ex-
cepting the lenses, for they could not procure good crown and
flint glass, and wanted also a skilful optician. With this
great defect, the establishment would certainly have failed,
unless they had endeavoured to supply it.

Mr Utzschneider now undertook a journey to make inquiry
respecting crown and flint glass, and respecting a skilful work-
ing optician ; but, after all hi? labours, he was convinced that
, the new establishment had no alternative but to form an opti-
cian within its own bosom. Through Captain Grouner of Berne,
he had heard of the labours of Louis M. Guinand, an optician
at Brenetz, in Neuchatel, (See this Journal^ No. iv. p. 855.)
and having received from him some specimens of his flint glass,
he was so pleased with them that he paid a visit to Brenetz,
and engaged Guinand to accompany him to Munich. As soon
as he arrived there, which was in ]805, M. Utzschneider cori-
structed furnaces for carrying on the experiments upon a well
organized plan. The first attempt created much expence, on
account of the repeated experiments which it required, but it
nevertheless furnished several good pieces of both kinds of
glass. The optician, Riggl, polished the first lenses in 1806
and 1807. At this period Fraunhofcr found himself in a very
critical situation. Professor Schiegg always encouraged him
to go to M. Utzschneider, but Fraunhofer was long in resolv-
ing to do this, believing that the latter had forgotten him, and
knowing that he was well satisfied with his own optician.

M. Utzschneider received Fraunhofer in a very friendly
manner, and after a short conversation, it was agreed that he
should also become an optician in the establislunent. Fraun-
hofer was then employed to calculate and polish lenses of con-

r. Ill-

Mevwir of the Life of M. Fraunhofer.

5

siderable dimensions which came from the furnaces of Bene- ^
dictbauern. These lenses were destined for the instruments of
the observatory of Buda, It was afterwards agreed to trans-
fer all the optical part of the establishment to Benedictbauern,
and to give the complete direction of it to Fraunhofer, Our
philosopher had already studied catoptrics, and had even writ-
ten a Memoir on the aberration which takes place without the
axis in reflecting telescopes. He showed that hyperbolic mir-
rors are preferable to parabolic ones, and he also communicat-
ed the invention of a machine for polishing hyperbolic surfaces.
He now, however, resolved to give up this branch of the sub-
ject, as his time was fully occupied in the preparation of lenses.

One of the most diflScult problems in practical optics is to '
give to spherical surfaces the last polish with that degree of
exactness which theory requires, because this final operation.,
destroys in part that form which had been previously given to
the surfaces. M. Fraunhofer succeeded in remedying this
evil by a machine which not only did not injure the fine sur-
face obtained by grinding, but which actually corrected the
irregularities committed in the first operation. It has also the
advantage of making the result independent of the skill of the
workman.

In examining the glass which he used in reference to the
undulations and striae which it contains, he found that, in the
flint glass manufactured at Benedictbauern, there was often
not a single piece free of those irregularities which disperse and
refract the light falsely. Pieces of the same melting had not
e/dn the same refracting power, and this was perhaps more
common in the English and French flint glass. After obtain*

T

ing these results, Fraunhofer reconstructed the furnaces, pro-
cured the necessary instruments, and took the direction of all
the meltings.

He had learned from experience, that flint glass could be
made so that a piece at the bottom of the pot had exactly the
same refractive power as a piece from the top ; but his success
was of short duration, for the succeeding meltings showed that
this was merely accidental. Undaunted, however, by failure,
he recommenced his experiments, in which he always melted
four quintals at once, and after long and severe labours, he

6 Memoir of the Life of M. Frauiilufer.

discovered the numerous causes which occasioned his want of
success.

As the English crown glass had many undulations and im-
purities, Fraunhofer resolved to manufacture it also. Diffi-
culties of a new kind here presented themselves, so that he
did not partly succeed till after a whole year's labour. He
found also, that with whatever degree of accuracy he followed
the theory in the construction of achromatic object-glasseSj
his expectations were never realized. On the one hand, he
was convinced that it was wrong to neglect certain quantities,
such as the thickness of the lens and the higher powers of
the apertures, merely to obtain commodious formulae ; and on
the other hand, there was no exact method for determining
the exponents of refraction and dispersion in the glass, used
for achromatic object-glasses. The first of these inconve-
niences he avoided by a new method, in which he neglected
no quantity upon which the required degree of exactness de-
pended. Hitherto, achromatic object-glasses had only been
calculated for rays proceeding from a point in the axis of the
lens, but Fraunhofer considered the deviations from all points
situated without the axis, and this is always a minimum ia
his object-glasses. In this consists principally the difference
between his glasses and those made in England.

The difficulty hitherto experienced in determining "the re-
fractive and dispersive powers of bodies, arises chiefly from
the circumstance that the spectrum has no definite termina-
tion, and that the passage from one colour to another was so
gradual, and indistinctly marked, that in large spectra the
angles could not be measured with a greater accuracy than
from ten to fifteen minutes. In order to avoid this inconve-

Fraunhofer succeeded, by a very ingenious contriv-
ance, in obtaining homogeneous light of each colour in the
spectrum. In these experiments, he discovered in the orange
compartment of the spectrum, produced by the light of the
fire, a bright line, which he afterwards found to exist in all
spectra, and by means of which he was enabled to determine
the refractive powers of the bodies which prod uced them.

By using prisms entirely exempt from veins, — by carefully
excluding all extraneous light, and even stopping those rays

. <& .^.'.i-d^ _. ' '" «- '--'' •'• • „', .->-Jr.-.A£___'_

Memoir of the I*ife of M, Fraimho/et\

1

which formed the coloured spaces that he wished to examine,
he discovered that the spectrum was intersected by a greajt
number of black lines parallel to one another, and perpendi-
cular to its length.* In the spectra formed by all solid and
fluid bodies, he not only discovered the same lines, (of which
he has reckoned 590 in all,) but he found that they had fixed
positions, and that the distances between them in diiFerent
spectra afforded precise measures of the action of the prism
on the rays which formed the. corresponding coloured spaces.
The valuable Memoir in which these discoveries are consign-
ed, was published in the fifth volume of the Memoirs of the
Academy of Munich for 1814 and 1815, and also in a sepa*
rate pamphlet entitled Bestimmung des BrechungSy und Far^
henzerstreuwigs, Vermogens verschiedener Glasarten* The
writer of this notice had the satisfaction of first translating
this memoir into English, and of publishing an abstract of its
results in the article Optics in the Edinburgh Encyclopedia.

About this time, in 1817, Fraunhofer was elected a Mem-
ber of the Academy of Bavaria, of which he was an active
supporter.

In speculating on the cause of the dark lines of the spec-
trum, our author was led to consider them as arising from the
interference of the rays, and he was induced to make a com-
plete series of experiments on the inflexion of light. These
experiments he published in the eighth volume of the Memoirs
of the Academy of Munich^ under the title of Neue Modejika-
tion des Lichtes durch gegenseilige Einwirlamg und Beugung
der Strahlen und gesetze derselben. In these experiments,
of which we have given a full account in the article Op-
tks in the Edinbuegh Encyclopedia, Fraunhofer employed
a heliostate for giving a fixed direction to the solar ray, and
he examined all the phenomena through a telescope mounted
upon a large theodolite, by means of which he measured the
deviation of the inflected light. The object-glass was twenty
lines in diameter ; its focal length was 16.9 inches, and its mag-
nifying power from 80 to 11 0. The heliostate was placed 38
feet 7 2 inches French measure from the centre of the theodo-

• Above twenty years ago, lines were discovered in the specti uai by Dr
Wollaston. See P/aV. jTranj. 1802.

8 * Memoir of the Life of M, Fraunhofer,

lite. The diameters of the apertures were measured by a
micrometer microscope, which showed distinctly the two hun-
dred thousandth part of an Inch^ and sometimes even half
that quantity. All the phenomena which he thus observed
and measured, he considered to be perfectly explicable on the
undulating system, with certain modifications ; and upon these
principles, he afterwards constructed a general analytical for-
mula, to express these new laws of light. From this formula,
it followed that these phenomena would be modified in a man-
ner not only singular, but apparently extremely complicated,
if a number of parallel lines could be made so fine, that 8000
of them were contained in one inch. After another set of ex-
periments, he invented a machine, by means of which he
could construct these systems of lines with that accuracy which
the theory required. The details of these experiments were
read before the Academy of Munich on the 14th June 1823,
and will be found in this and the subsequent number of this
Journal.

M. Fraunhofer likewise applied himself to the study of va-
rious atmospheric phenomena, such as halos, parhelia, &c.
which he published in Professor Shumacher's Astronomische
AbhandlungcUi and of which we have given a notice in the last
number of this Journal, p. 34>8.

Such is a brief sketch of the scientific researches of Fraun-
Jiofer, but, valuable though they be, they are in no respect
to be compared with his practical labours as an optician.
His minor inventions are a new Heliometer^ a repeating
wire Micrometer y and an improved annular Micrometer,
The principal instruments which he has made, are the great
parallactic telescope, constructed for the observatory of Dor-
pat, and of which we have given a full description and a
drawing in No. iv. p. 306 of this Journal* The prime cost of
this instrument was L. 950. Its aperture is nine inches, and
its focal length ISJ feet. His next great work was another

I

achromatic telescope, ordered by the King of Bavaria, and
which has an object-glass twelve inches in diameter, and eight
feet in focal length, but it is not yet completed. Although
engaged in works of such magnitude, Fraunhofer was at the
same time carrying on others on a less scale, though not of

Memoir of the Life ofM. Fraunfiqfer. '9

less importance to science. The Astronomical Institution of
Edinburgh, in the year 18^5, ordered from him a very large
and complete transit instrument, with a telescope eight feet and
$1 half in focal length, and six inches aperture. Upon the re-
ceipt of this order, he constructed three object-glasses of these
dimensions, one for the Royal Observatory of Edinburgh,
another for a heliometer for M. Bessel, and a third as a spare
one in case M. Bessel's object-glass should meet with any ac-
cident in the bisection ; and, fortunately for science, these ob-
ject-glasses are all completed.

In the year 1820, when M, Reichenbach left the copart-
nery, MM. Utzschneider and Fraunhofer entered into a ne^
contract for continuing their optical establishment. The for-
mer presented to Fraunhofer a share in the concern, equal
to about 24,000 francs, so that, from having several other
sources of income, he was now comfortable and independent.
Inspired by his success and good fortune, all the activity of
his mind was called forth, and he took the establishment en-
tirely under his direction. Since 1817 it had been trans-
ferred to Munich, and the business had increased to such a
degree, that J^^ workmen are at present employed.

In 1823 M. Fraunhofer was appointed keeper of the phy-
sical cabinet of the academy of Munich, a situation to which
a pension was attached. In 1824 after the public exhibition
of the great telescope of Dorpat, the King of Bavaria honour-
ed him with the rank of a chevalier of the order of Civil Merit.
He was also elected a member of several foreign societies,
among which we may mention the Society of Arts in our own
city. The university of Erlangen also conferred upon him
the title of Doctor in Philosophy.

Thus honoured and respected both at home and abroad,
Fraunhofer was enjoying all the happiness which character
and reputation and a moderate independence never fail to
yield. His mind was occupied with great views of scientific
ambition which he could not have failed to realize, and such
was the perfection to which he had brought his art, that he
was willing to undertake an achromatic telescope, with an ob-
ject-glass eighteen inches in aperture^ and we have now before
us a letter in which he fixes even the price of this stupendous

i^ Memoir of the Life ofM. Fraiuiltofer*

instrument. But he was not destined to accomplish so great
an undertakinff. In October 1825 he was attacked with a
pulmonary complaint, from which he never recovered. The
injury which he sustained by the fall of his house seems to
have left some effects behind it, and for several years he had
suffered from glandular abscesses. He was, however, seldom
obliged to discontinue his labours, and there is reason to think
that he suffered from exposure to the heat of his furnaces.
His faculties never for a moment left him ; and in his few
last days, his mind was occupied with the idea of a journey,
to France and Italy for the recovery of his health. He was
cut off on the 7th June 182C> in the fortieth year of his age.
A few days before this event he had received from the
King of Denmark the diploma of Chevalier of the order of
Dannebroga. The whole of the city of Munich took a lively
interest in his disease, and felt the most sincere sorrow for his
, The magistrates of the city permitted M, Utzschneider
to choose a place for his tomb, and he was interred by the
side of the great mechanician M. Reichenbach, who had died
a short time before.

Bavaria has thus lost one of the most distinguished of her sub-
jects, and centuries may elapse before Munich receives withia
her walls an individual so highly gifted and so universally esteem-
ed. But great as her loss is, it is not rendered more poignant
by the reflection that he lived unhonoured and unrewarded.
His own sovereign Maximilian Joseph was his earliest and his
latest patron, and by the liberality with which he conferred
civil honours and pecuniary rewards on Joseph Fraunhofer, he
has immortalized his own name, and added a new lustre to the
Bavarian crown. In thus noticing the honours which a grate-
ful sovereign had conferred on the distinguished improver of
the achromatic telescope, it is impossible to subdue the morti-
fying recollection, that no wreath of British gratitude has yet
adorned the inventor of that noble instrument. England may
well blush when she hears the name of Dollond pronounced
without any appendage of honour, and without any associa-
tion of gratitude. Even that monumental fame which she
used to dispense so freely to the poets whom she starved, has
been denied to this benefactor of science, and Westminster

■k^^^^^i^

RemarTvs on Mount Vesuvius*

11

Abbey has not opened her hallowed recesses to the remains of
a man who will ever be deemed one of the £nest geniuses of
his age, and who had exalted that genius by learning and
piety of no ordinary kind.

Thus neglected and mortified, it is not a matter of sur-'
prise that this branch of science and of art should seek for
shelter in a more hospitable land, and that the pre-eminence
which England had so long enjoyed in the manufacture of the
achromatic telescope should be transferred to a foreign coun-.
try. The loss of Fraunhofer holds out to us an opportunity
of recovering what we have lost, and we earnestly hope that
the Royal Society of London and the Board of Longitude
will not allow it to pass. Great Britain has hitherto left the
sciences and the arts to the care of Individual enterprise, and
to the patronage of commercial speculation ; but now, when
all Europe has become our rivals, when every sovereign, like
the Ptolemies of old,, is collecting round his throne, the wis-
dom even of foreign states, is it not time that she should
start from her lethargy, and endeavour to secure what is yet
left ? The British minister who shall first establish a sys-
tem of effectual patronage for our arts and sciences, and who
shall deliver them from the fatal incubus of our patent laws,
will be regarded as the Colbert of his age, and will secure
to himself a more glorious renown than he could ever obtain
from the highest achievements in legislation or in politics.

Aet. H.-^RemarJcs on Mount Vesuvius, Communicated by

a CORKESPONDENT.

Having recently performed two excursions to the summit of
Mount Vesuvius, it occurs to me that some of the particulars
which I observed may possibly not be very generally known,
and consequently thought worthy of a place in the Edinburgh
Journal of Science. I shall therefore give an account of my
second expedition, adding any particulars which I find in my
notes on the first. We left Naples about eleven a. m, and hav-
ing arrived at Resina found Salvatore ready to accompany us,
we mounted asses, and after a long ride during torrents of