_UNDER THE SUPERINTENDENCE OF THE SOCIETY FOR THE DIFFUSION OF USEFUL
KNOWLEDGE._
THE
GALLERY OF PORTRAITS:
WITH
MEMOIRS.
VOLUME III.
LONDON:
CHARLES KNIGHT, 22, LUDGATE-STREET.
1834.
[PRICE ONE GUINEA, BOUND IN CLOTH.]
LONDON:
PRINTED BY WILLIAM CLOWES,
Duke-Street, Lambeth.
------------------------------------------------------------------------
PORTRAITS, AND BIOGRAPHIES
CONTAINED IN THIS VOLUME.
1. Erskine 1
2. Dollond 12
3. John Hunter 19
4. Petrarch 25
5. Burke 33
6. Henry IV. 41
7. Bentley 49
8. Kepler 59
9. Hale 66
10. Franklin 77
11. Schwartz 86
12. Barrow 94
13. D’Alembert 101
14. Hogarth 106
15. Galileo 113
16. Rembrandt 121
17. Dryden 127
18. La Perouse 135
19. Cranmer 141
20. Tasso 149
21. Ben Jonson 156
22. Canova 165
23. Chaucer 176
24. Sobieski 184
⁂ It should have been stated in the Life of D’Alembert, that that Life
was mostly taken from the Penny Cyclopædia, with some alterations by the
Editor of this work.
[Illustration:
_Engraved by R. Woodman._
ERSKINE.
_From the original Picture by Hoppner
in his Majesty’s Collection at Windsor._
Under the Superintendance of the Society for the Diffusion of Useful
Knowledge.
_London, Published by Charles Knight, Ludgate Street, & Pall Mall
East._
]
[Illustration]
ERSKINE.
The Honourable Thomas Erskine was the third son of David Earl of Buchan,
a Scottish peer of ancient family and title, but reduced fortune. He was
born in January 1748, and received the rudiments of his education,
partly at the High School of Edinburgh, partly at the University of St.
Andrews. But the straitened circumstances of his family rendered it
necessary for him to embrace some profession at an early age; and he
accordingly entered the navy as a midshipman in 1764. Not thinking his
prospects of advancement sufficiently favourable to render his
continuance in that service expedient, he exchanged it in the year 1768
for that of the army. In 1770 he married his first wife, Frances, the
daughter of Daniel Moore, M.P. for Marlow; and soon after went with his
regiment to Minorca, where he remained three years. Soon after returning
to England he changed his profession again. It has been said that he
took this step against his own judgment, and on the pressing entreaties
of his mother, a woman of lofty and highly cultivated mind, the sister
of Sir James Stewart, whose scientific writings, especially upon
political philosophy, have rendered his name so famous, and the daughter
of a well known Scotch lawyer and Solicitor-General of the same name.
But it is certain that at this time he had acquired considerable
celebrity in the circles of London society; and it is hard to suppose
that he was not sensible of his own brilliant qualifications for
forensic success. Whatever the cause, he commenced his legal life in
1775, in which year he entered himself as a student of Lincoln’s Inn,
and also as a fellow commoner of Trinity College, Cambridge; not with a
view to university honours or emoluments, but to obtain the honorary
degree of M.A., to which he was entitled by his birth, and thereby to
shorten the period of probation, previous to his being called to the
bar. He gave an earnest, however, of his future eloquence, by gaining
the first declamation prize, annually bestowed in his college. The
subject which he chose was the Revolution of 1688. His professional
education was chiefly carried on in the chambers of Mr. Buller and Mr.
Wood, both subsequently raised to the bench. In Trinity term, 1778, he
was called to the bar.
Mr. Erskine’s course was as rapid as it was brilliant. In the following
term, Captain Baillie, Lieutenant-Governor of Greenwich Hospital, was
prosecuted for an alleged libel on other officers of that establishment,
contained in a pamphlet written to expose the abuses which existed
there, and bearing heavily on the character of the Earl of Sandwich,
then First Lord of the Admiralty. It is believed that on this occasion
Mr. Erskine made his first appearance in court. His speech was
characterized by great warmth and eloquence, and a most fearless
assertion of matters not likely to be palatable either to the Court or
the Government. And this is the more worthy of notice, because it shows
that the boldness which he afterwards displayed in causes more nearly
connected with the liberties of England, was not the safe boldness of a
man strong in professional reputation, and confident in his experience
and past success, but the result of a fixed determination to perform, at
all hazards, his whole duty to his client. The best testimony to the
effect of this speech is to be found in the anecdote, that thirty briefs
were presented to him by attorneys before he left the court.
We must hasten very briefly through the events of Mr. Erskine’s life to
make room for speaking at somewhat more length of a very few of his most
remarkable performances. He rose at once into first rate junior business
in the Court of King’s Bench, and received a patent of precedence in May
1783, having practised only for the short space of five years. He
belonged to the Home Circuit in the early part of his professional life;
but soon ceased to attend it, or any other, except on special retainers,
of which it is said that he received more than any man in his time or
since.
In his political life he was a firm adherent of Mr. Fox: but his success
in Parliament, which he entered in 1783 as member for Portsmouth, was
not commensurate with the expectations which had been raised upon the
brilliant powers of oratory which he had displayed at the bar. On
attaining his majority in 1783, the Prince of Wales appointed Mr.
Erskine, with whom he lived in habits of intimacy, to be his
Attorney-General. This office he was called on to resign in 1792, in
consequence of his refusing to abandon the defence of Paine, when he was
prosecuted for a libel, as author of the ‘Rights of Man:’ and his
removal, though not a solitary, is fortunately a rare instance in modern
times, of an advocate being punished for the honest discharge of his
professional duties. Five years afterwards he conducted the prosecution
of the ‘Age of Reason;’ and in 1802 he was appointed Chancellor of the
Duchy of Cornwall. On the formation of the Grenville administration, in
1806, he was appointed Chancellor of Great Britain, and raised to the
peerage, by the title of Baron Erskine, of Restormel Castle in Cornwall.
The short period during which he presided in the Court of Chancery,
makes it difficult to estimate how far his extraordinary powers of mind,
and in particular the eminently legal understanding which he possessed,
would have enabled him to overcome the difficulties of so new a
situation. But his judgments have, generally speaking, stood the test of
subsequent investigation; and his admirable conduct in the impeachment
of 1806, over which he presided as Lord High Steward, uniting the
greatest acuteness and readiness with singular firmness of purpose, and
all that urbanity which neither in public nor in private life ever
quitted him for an instant, may be said to have restored to life a mode
of trial essential to our constitution, though discredited by the
vexatious procrastination which had characterized the last instance of
its use.
On the dissolution of the Grenville ministry, which occurred about a
year after its formation, Lord Erskine retired in a great degree from
public life. In 1808 he took an active share in opposing the measure of
commercial hostility, so well known under the name of the Orders in
Council, and still so deeply felt: and his speech against the Jesuits’
Bark Bill, which was not reported, is said to have been worthy of his
most celebrated efforts, both for argument and eloquence. In 1809 he
introduced into the House of Lords a bill for the prevention of cruelty
to animals, which passed that branch of the legislature, but was thrown
out by the Commons. The part, too, which he took upon the memorable
proceedings of 1820, relative to the Queen’s trial, will long be
remembered, marked as it was by all the highest qualities of the
judicial character: and his arguments upon the Banbury case a few years
before, only leave a regret that he did not devote more of his leisure
to the legal business of the House of Lords.
After his retirement, Lord Erskine occupied himself occasionally in
literary pursuits. In this period he composed the Preface to Mr. Fox’s
Speeches, and the political romance of Armata. His only other written
work of importance is a pamphlet, entitled ‘View of the Causes and
Consequences of the War with France,’ which appeared in 1797, and ran
through the extraordinary number of forty-eight editions. But he is not
to be considered as a literary man: on the contrary, it is one of the
many singularities in his history, that with a scanty stock of what is
usually called literature, he should have been one of our most purely
classical speakers and writers. His study was confined to a few of the
greatest models; and these he almost knew by heart.
The later years of his life were harassed by pecuniary embarrassment,
arising partly from the loss of his large professional income,
inadequately replaced by a retiring pension of £4000; and partly from an
unfortunate investment of the fruits of his industry in land, which
yielded little return when the period of agricultural depression
arrived. His first wife died in 1805: and an ill-assorted second
marriage, contracted much later in life, is supposed to have increased
his domestic disquietudes, as it certainly injured his reputation, and
gave pain to his friends. He was seized with an inflammation of the
chest while travelling towards Scotland, and died at Almondale, his
brother’s seat, near Edinburgh, November 17, 1823. Immediately after his
decease, the members of that profession of which he had been at once the
ornament and the favourite, caused a statue of him to be executed. When
the marble was denied admittance within those walls which had so often
been shaken by the thunder of his eloquence, they placed it in the hall
of Lincoln’s Inn, where he had presided as chancellor; a lasting
monument to those who study the law, that subserviency is not necessary
to advancement, and that they will be held in grateful remembrance by
their professional brethren, who boldly uphold the liberties of their
country.
In speaking, which we can do very briefly, of Lord Erskine’s
professional merits, our attention is directed to those of his speeches
which bear on two great subjects, the Liberty of the Press, and the
doctrine of Constructive Treason, not merely because they embrace his
most laboured and most celebrated efforts, nor for the paramount
importance of these subjects in a constitutional point of view; but also
because we possess a collection of those speeches corrected by himself,
while of the numberless arguments and addresses delivered on other
subjects during a most active period of twenty-eight years, but very few
have been authentically reported. From those which are preserved, the
rising generation can form but an inadequate idea of this extraordinary
man’s power as an advocate; such is said, by those who yet remember him,
to have been the witchery of his voice, eye, and action; such his
intuitive perception of that which at the instant was likely to have
weight with a jury. His peculiar skill in this respect is thus described
by a distinguished writer in the Edinburgh Review, in commenting upon a
brilliant passage, which we shall presently have occasion to quote. “As
far as relates to the character of Lord Erskine’s eloquence, we would
point out as the most remarkable feature in this passage, that in no one
sentence is the subject, the business in hand, the case, the client, the
verdict, lost sight of; and that the fire of that oratory, or rather of
that rhetoric (for it was quite under discipline), which was melting the
hearts and dazzling the understandings of his hearers, had not the power
to touch for one instant the hard head of the _Nisi Prius_ lawyer, from
which it radiated; or to make him swerve, by one hair’s breadth even,
from the minuter details most befitting his purpose, and the alternate
admissions and disavowals best adapted to put his case in the safest
position. This, indeed, was the grand secret of Mr. Erskine’s
unparalleled success at the English bar. Without it he might have filled
Westminster Hall with his sentences, and obtained a reputation for
eloquence, somewhat like the fame of a popular preacher or a
distinguished actor: but his fortunes,—aye, and the liberties of his
country,—are built on the matchless skill with which he could subdue the
genius of a first rate orator to the uses of the most consummate
advocate of the age.”—(Edinburgh Review, vol. xvi. p. 116–7, 1810.)
Mr. Erskine’s speeches against the doctrine of Constructive Treason were
delivered in behalf of Lord George Gordon, when accused of high treason
as the ringleader of the riots in 1780, and in behalf of Messrs. Hardy
and Horne Tooke, when attacked by the whole weight of Government in
1794. In the first of these he begins by laying down broadly and
distinctly the law of treason, as defined by the celebrated statute of
Edward III. He proceeds, carefully avoiding to offend the probable
temper of the jury by asserting either the prudence or legality of Lord
George Gordon’s conduct, to show the total failure of evidence to bring
his intentions within the scope of the act; the utter want of pretence
for assuming that he had levied war on the King, the crime charged in
the indictment; and the utter want of proof to connect him, or the
Protestant Association, of which he was chairman, with the outrages
committed by a rabble, insignificant alike in numbers and character. He
enters into a minute examination of the crown evidence; lays bare the
infamy of one witness; exposes the forced constructions by which alone
any legal or moral guilt can be attached to his client; and, warming in
his subject, breaks out into an appeal to the jury, the effect of which
is said to have been electric. And it has been justly observed, that by
such an effect alone could the boldness of the attempt have been
justified: failure would have been destruction. The eloquence of this
speech is even less remarkable than the exquisite judgment and
professional skill by which that eloquence is controlled.
In the State Trials of 1794, the prisoners, it is well known, were
proceeded against separately. Hardy’s turn came first. They were charged
with compassing the death of the King, the evidence of this intention
being a conspiracy to subvert by force the constitution of the country,
under pretence of procuring, by legal means, a reform in the House of
Commons. It must be evident to every one that this was stretching the
doctrine of constructive treason to the utmost: yet Parliament had
passed a bill, declaring in the preamble that such a conspiracy did
actually exist; and this being asserted on such high authority, and no
doubt existing of the prisoners being deeply engaged in the design to
procure a reform in Parliament, they came to their trial under the most
serious disadvantages. On this occasion, as in defence of Lord George
Gordon, Mr. Erskine began by explaining the law of treason, under the
statute of Edward III. He showed the strictness with which it had been
defined and limited by the most eminent constitutional lawyers; and
argued, that granting the intention to hold a general convention, with
the view of obtaining by that means a reform in Parliament; granting
even that this amounted to a conspiracy to levy war for that purpose,
still the offence would not be the high treason charged by the
indictment, unless the conspiracy to levy war were directly pointed
against the King’s person. And that there was no want of affection for
the King himself, appeared fully even from the evidence for the
prosecution. He maintained that the clearest evidence should be required
of the evil intention, especially when so different from the open and
avowed object of the prisoners. He proceeded to show that their
ostensible object, so far from necessarily involving any evil designs,
was one which had been advocated by the Earl of Chatham, Mr. Burke, Mr.
Pitt himself; and that the very measures of reform which it was sought
to introduce, had been openly avowed and inculcated by the Duke of
Richmond, then holding office in the ministry of which Mr. Pitt was
chief. Mr. Hardy, Mr. Tooke, and Mr. Thelwall were severally and
successively acquitted, and all men now confess that to the powers and
the courage of this matchless advocate in that day of its peril, the
preservation of English liberty must be mainly ascribed. The other
prosecutions were then abandoned.
Mr. Erskine’s powerful and fearless support of the liberty of the
subject on all occasions rendered him especially sought after by all
persons accused of political libels; and a large proportion of his most
important speeches are on these subjects. The earliest reported, and for
their consequences the most remarkable, are the series of speeches which
he delivered in behalf of the Dean of St. Asaph, in 1784. Of the merits
of the case we have not room to speak: but it is important for the
influence which it had in determining the great question, whether in
prosecutions for libel, the jury is to judge of fact alone, or of law
and fact conjointly. For many years it had been the doctrine of the
courts, that juries had no cognizance of the nature of an imputed libel,
beyond ascertaining how far the meaning ascribed in the indictment to
passages charged as libellous was borne out by evidence; the truth of
these, and the fact of the publication being ascertained, it was for the
judge to determine whether the matter were libellous or no. This
doctrine was controverted by Mr. Erskine in his speech for the Dean of
St. Asaph, and maintained by the judge who tried the case; and on the
ground of misdirection, Mr. Erskine moved for a new trial. On this
occasion he went into an elaborate argument to prove that it was the
office of the jury, not of the judges, to pronounce upon the intention
and tendency of an alleged libel; and to him is ascribed the honour of
having prepared the way for the Libel Bill, introduced by Mr. Fox in
1792, and seconded by himself, in which the rights and province of the
jury are clearly defined, and the position established, for which he, in
a small minority of his professional brethren, had contended. This was a
triumph of which the oldest, and most practised lawyer might have been
proud; it is doubly honourable to one young in years, and younger in
professional experience.
Equal perhaps to those in importance, for it bore directly on the
liberty of the press, and superior in brilliance of execution, is the
speech in behalf of Stockdale, the bookseller, who was prosecuted for a
libel on the House of Commons, in consequence of having published a
pamphlet commenting on the articles of impeachment brought against Mr.
Hastings, and containing some passages by no means complimentary to some
portion of that honourable body. The fact of the publication being
admitted, Mr. Erskine, agreeably to the provisions of the Libel Act,
proceeded to address the jury on the merits of the work. It was his
argument, that the tenor of the whole, and the intentions of the writer,
were to be regarded; and that if these should be found praiseworthy, or
innocent, the presence of a few detached passages, which, taken
separately, might seem calculated to bring the House of Commons into
contempt, were altogether insufficient to justify conviction. This
speech may be selected as one of the finest examples of Mr. Erskine’s
oratory, whether for the skill displayed in managing the argument, the
justness of the principles, the exquisite taste with which they are
illustrated and enforced, or the powerful eloquence in which they are
embodied; and from this, in conclusion, we would extract one passage as
a specimen of his powers. It is sufficient to state in introduction,
that the pamphlet in question was a defence of Mr. Hastings, and that,
among other topics, it urged the nature of his instructions from his
constituents. Commenting on this, the orator proceeds in a strain which
few persons, not hardened by long converse in affairs of state, will
read without emotion, or without a deep sense of the justice of the
sentiments, the gravity of the topics introduced.
“If this be a wilfully false account of the instructions given to Mr.
Hastings for his government, and of his conduct under them, the author
and publisher of this defence deserve the severest punishment, for a
mercenary imposition on the public. But if it be true, that he was
directed to ‘make the safety and prosperity of Bengal the first object
of his attention,’ and that under his administration it has been safe
and prosperous; if it be true that the security and preservation of our
possessions and revenues in Asia were marked out to him as the great
leading principle of his government, and that those possessions and
revenues amidst unexampled dangers have been secured and preserved; then
a question may be unaccountably mixed with your consideration, much
beyond the consequence of the present prosecution, involving perhaps the
merit of the impeachment itself which gave it birth; a question which
the Commons, as prosecutors of Mr. Hastings, should in common prudence
have avoided; unless, regretting the unwieldy length of their
prosecution against him, they wished to afford him the opportunity of
this strange anomalous defence. For although I am neither his counsel,
nor desire to have any thing to do with his guilt or innocence, yet in
the collateral defence of my client I am driven to state matter which
may be considered by many as hostile to the impeachment. For if our
dependencies have been secured, and their interests promoted, I am
driven in the defence of my client to remark, that it is mad and
preposterous to bring to the standard of justice and humanity, the
exercise of a dominion founded upon violence and terror. It may, and
must be true, that Mr. Hastings has repeatedly offended against the
rights and privileges of Asiatic government, if he was the faithful
deputy of a power which could not maintain itself for an hour without
trampling upon both; he may and must have offended against the laws of
God and nature, if he was the faithful Viceroy of an empire wrested in
blood from the people to whom God and nature had given it; he may and
must have preserved that unjust dominion over timorous and abject
nations by a terrifying, overbearing, insulting superiority, if he was
the faithful administrator of your government, which, having no root in
consent or affection, no foundation in similarity of interests, nor
support from any one principle which cements men together in society,
could only be upheld by alternate stratagem and force. The unhappy
people of India, feeble and effeminate as they are from the softness of
their climate, and subdued and broken as they have been by the knavery
and strength of civilization, still occasionally start up in all the
vigour and intelligence of insulted nature. When governed at all, they
must be governed with a rod of iron; and our empire in the east would
long since have been lost to Great Britain, if civil skill and military
prowess had not united their efforts, to support an authority which
Heaven never gave, by means which it never can sanction.
“Gentlemen, I think I can observe that you are touched with this way of
considering the subject, and I can account for it. I have not been
considering it through the cold medium of books, but have been speaking
of man and his nature, and of human dominion, from what I have seen of
them myself among reluctant nations submitting to our authority. I know
what they feel, and how such feelings can alone be repressed. I have
heard them in my youth, from a naked savage, in the indignant character
of a prince surrounded by his subjects, addressing the Governor of a
British colony, holding a bundle of sticks in his hand, as the notes of
his unlettered eloquence. ‘Who is it,’ said the jealous ruler over the
desert, encroached upon by the restless foot of English adventure; ‘who
is it that causes this river to rise in the high mountains, and to empty
itself into the ocean? Who is it that causes to blow the loud winds of
winter, and that calms them again in the summer? Who is it that rears up
the shade of these lofty forests, and blasts them with the quick
lightning at his pleasure? The same Being, who gave to you a country on
the other side of the waters, and gave ours to us; and by this title we
will defend it,’ said the warrior, throwing down his tomahawk on the
ground, and raising the war-cry of his nation. These are the feelings of
subjugated man all round the globe; and depend upon it, nothing but fear
will control, where it is vain to look for affection.
“These reflections are the only antidotes to those anathemas of
superhuman eloquence which have lately shaken these walls that surround
us; but which it unaccountably falls to my province, whether I will or
no, a little to stem the torrent of, by reminding you that you have a
mighty sway in Asia which cannot be maintained by the finer sympathies
of life, or the practice of its charities and affections. What will they
do for you when surrounded by two hundred thousand men with artillery,
cavalry, and elephants, calling upon you for their dominions which you
have robbed them of? Justice may, no doubt, in such a case forbid the
levying of a fine to pay a revolting soldiery; a treaty may stand in the
way of increasing a tribute to keep up the very existence of the
government; and delicacy for women may forbid all entrance into a zenana
for money, whatever may be the necessity for taking it. All these things
must ever be occurring. But under the pressure of such constant
difficulties, so dangerous to national honour, it might be better
perhaps to think of effectually securing it altogether, by recalling our
troops and merchants, and abandoning our Oriental empire. Until this be
done, neither religion nor philosophy can be pressed very far into the
aid of reformation and punishment. If England, from a lust of ambition
and dominion, will insist on maintaining despotic rule over distant and
hostile nations, beyond all comparison more numerous and extended than
herself, and gives commission to her Viceroys to govern them, with no
other instructions than to preserve them, and to secure permanently
their revenues; with what colour of consistency or reason can she place
herself in the moral chair, and affect to be shocked at the execution of
her own orders; adverting to the exact measure of wickedness and
injustice necessary to their execution, and complaining only of the
excess as the immorality; considering her authority as a dispensation
for breaking the commands of God, and the breach of them only punishable
when contrary to the ordinances of man.
“Such a proceeding, Gentlemen, begets serious reflections. It would be
better perhaps for the masters and the servants of all such governments
to join in supplication, that the great Author of violated humanity may
not confound them together in one common judgment.”
These speeches, on constructive treason, and on subjects relating to the
liberty of the press, fill four octavo volumes. A fifth was subsequently
published, containing speeches on miscellaneous subjects; among which
those in behalf of Hadfield and for Mr. Bingham are especially worthy of
attention. The latter is one of the most affecting appeals to the
feelings ever uttered. Hadfield is notorious for having discharged a
pistol at George III. in Drury Lane Theatre. He was a soldier, who had
been dreadfully wounded in the head, and other parts of the body; and no
doubt could be entertained but that he was of unsound mind. Whether his
insanity was of such a nature, that it could be pleaded in excuse for an
attempt to murder, was a harder question to decide; and the speech in
his behalf, besides many passages of much power and pathos, contains a
masterly exposition of the principles by which a court of law should be
guided in examining the moral responsibility of a person labouring under
alienation of mind. Hadfield, we need hardly say, was acquitted.
No life of Lord Erskine has yet been written on a scale calculated to do
justice to the subject. The fullest which we have seen is contained in
the ‘Lives of British Lawyers,’ in Lardner’s Cyclopædia: there is also a
scanty memoir in the Annual Biography and Obituary, from which the facts
contained in this sketch are principally derived.
[Illustration: Statue of Lord Erskine in Lincoln’s Inn Hall.]
[Illustration]
DOLLOND.
The parents of this eminent discoverer in optics, to whom we are chiefly
indebted for the high perfection of our telescopes, were French
Protestants resident in Normandy, whence they were driven by the
revocation of the edict of Nantes in 1685. With many others of their
class, they took up their residence in Spitalfields, where John Dollond,
the subject of this memoir[1], was born, June 10, 1706. It has been
supposed, and among others by Lalande, that the name is not French; if
we were to hazard a conjecture, we should say that it might have been an
English corruption of _D’Hollande_. While yet very young, John Dollond
lost his father; and he was obliged to gain his livelihood by the loom,
though his natural disposition led him to devote all his leisure hours
to mathematics and natural philosophy. Notwithstanding the cares
incumbent upon the father of a family (for he married early) he
contrived to find time, not only for the above-mentioned pursuits, but
for anatomy, classical literature, and divinity. He continued his quiet
course of life until his son, Peter Dollond, was of age to join him in
his trade of silk-weaving, and they carried on that business together
for several years. The son, however, who was also of a scientific turn,
and who had profited by his father’s instructions, quitted the silk
trade to commence business as an optician. He was tolerably successful,
and after some years his father joined him, in 1752.
Footnote 1:
For the details of this life, we are mostly indebted to the Memoir of
Dr. Kelly, his son-in-law, from which all the existing accounts of
Dollond are taken. This book has become very scarce, and we are
indebted for the opportunity of perusing it to the kindness of G.
Dollond, Esq.
[Illustration:
_Engraved by J. Posselwhite._
DOLLOND.
_From an original Picture
in the Royal Observatory, Greenwich._
Under the Superintendance of the Society for the Diffusion of Useful
Knowledge
_London, Published by Charles Knight, Ludgate Street, & Pall Mall
East._
]
The first improvement made by the elder Dollond in the telescope, was
the addition of another glass to the eye-piece, making the whole number
of glasses in the instrument (the object-glass included) six instead of
five. This he communicated to the Royal Society in 1753, through his
friend James Short, well known as an optician and astronomer, who also
communicated all his succeeding papers. By his new construction, an
increase in the field of view was procured, without any corresponding
augmentation of the unavoidable defects of the instrument. In May, 1753,
Dollond communicated to the Royal Society his improvement of the
micrometer. In 1747 Bouguer proposed to measure the distance of two very
near objects (the opposite edges of a planet, for example) by viewing
them through a conical telescope, the larger end of which had two
object-glasses placed side by side, the eye-glass being common to both.
The distance of the objects was determined by observing how far it was
necessary to separate the centres of the object-glasses, in order that
the centre of each might show an image of one of the objects. Mr.
Dollond’s improvement consisted in making use of the same object-glass,
divided into two semicircular halves sliding on one another, as
represented in the diagrams in page 18; the first of which is an oblique
perspective view of the divided glass, and the second a side view of the
same, in such a position, that the images of the stars A and B coincide
at C.
If the whole of an object-glass were darkened, except one small portion,
that portion would form images similarly situated to those formed by the
whole glass, but less illuminated. Each half of the object-glass, when
separated from the other, forms an image of every object in the field;
and the two images of the same object coincide in one of double
brightness, when the halves are brought together so as to restore the
original form. By placing the divided diameter in the line of two near
objects, A and B, whose distance is to be measured, and sliding the
glasses until the image of one formed by one half comes exactly into
contact with the image of the other formed by the other half, the
angular distance of the two objects may be calculated, from observation
of the distance between the centres of the two halves. This last
distance is measured on a scale attached to the instrument; and when
found, is the base of the triangle, the vertex of which is at C, and the
equal sides of which are the focal lengths of the glasses. This
micrometer Dollond preferred to apply to the reflecting telescope; his
son afterwards adapted it to the refracting telescope; and it is now,
under the name of the _divided object-glass micrometer_, one of the most
useful instruments for measuring small angles.
But the fame of Dollond principally rests upon his invention of
_achromatic_, or colourless telescopes, in which the surrounding fringe
of colours was destroyed, which had rendered indistinct the images
formed in all refracting telescopes previously constructed. He was led
to this practical result by the discovery of a principle in optics, that
the _dispersion_ of light in passing through a refracting medium, that
is, the greater or less length through which the coloured _spectrum_ is
scattered, is not in proportion to the _refraction_, or angle through
which the rays are bent out of their course. Newton asserted that he had
found by experiments, made with water and glass, that if a ray of light
be subjected to several refractions, some of which correct the rest, so
that it emerges parallel to its first direction, the dispersion into
colours will also be corrected, so that the light will be restored to
whiteness. This is not generally true: it is true if one substance only
be employed, or several which have the same, or nearly the same,
_dispersive power_[2]. Mr. Peter Dollond afterwards satisfactorily
explained the reason of Newton’s mistake, by performing the same
experiment with Venetian glass, which, in the time of the latter, was
commonly used in England; from which he found that the fact stated by
Newton was true, as far as regarded that sort of glass. Had Newton used
flint glass, he would have discovered that dispersion and refraction are
not necessarily corrected together: he would then have been led to the
difference between refractive and dispersive power, and would have
concluded from his first experiment that Venetian glass and water have
their dispersive powers very nearly equal. As it was, he inferred that
the refracting telescope could never be entirely divested of colour,
without entirely destroying the refraction, that is, rendering the
instrument no telescope at all; and, the experiment being granted, the
conclusion was inevitable. It is well known that he accordingly turned
his attention entirely to the reflecting telescope.
Footnote 2:
See Penny Cyclopædia, article Achromatic, for this and other terms
employed in this life.
In 1747, Euler, struck by the fact that the human eye is an achromatic
combination of lenses, or nearly so, imagined that it might be possible
to destroy colour by employing compound object-glasses, such as two
lenses with an intermediate space filled with water. In a memoir
addressed to the Academy of Berlin, he explained his method of
constructing such achromatic glasses, and proposed a new law of
refrangibility, different from that of Newton. He could not, however,
succeed in procuring a successful result in practice. Dollond, impressed
with the idea that Newton’s experiment was conclusive, objected to
Euler’s process in a letter to Mr. Short; which the latter persuaded the
author to communicate, first to Euler, and then, with his answer, to the
Royal Society. Assuming Newton’s law, Dollond shows that Euler’s method
would destroy all refraction as well as dispersion. The latter replies,
that it is sufficient for his purpose that Newton’s law should be
_nearly_ true; that the theory propounded by himself does not differ
much from it; and that the structure of the eye convinces him of the
possibility of an achromatic combination. Neither party contested the
general truth of Newton’s conclusion.
A new party to the discussion appeared in the field in the person of M.
Klingenstierna, a Swedish astronomer, who advanced some mathematical
reasoning against the law of Newton, and some suspicions as to the
correctness of his experiment. The latter being thus formally attacked,
Mr. Dollond determined to repeat it, with a view of settling the
question, and his result was communicated to the Royal Society in 1758.
By placing a prism of flint glass inside one of water, confined by glass
planes, so that the refractions from the two prisms should be in
contrary directions, he found that when their angles were so adjusted,
that the refraction of one should entirely destroy that of the other,
the colour was far from being destroyed; “for the object, though not at
all refracted, was yet as much infested with prismatic colours, as if it
had been seen through a glass wedge only, whose refracting angle was
near thirty degrees.” It was thus proved that the correction of
refraction, and the correction of dispersion, are not necessarily
consequent the one on the other. Previously to communicating this
result, Dollond had, in 1757, applied it to the construction of
achromatic glasses, consisting of spherical lenses with water between
them: but finding that the images, though free from colour, were not
very distinct, he tried combinations of different kinds of glass; and
succeeded at last in forming the achromatic object-glass now used,
consisting of a convex lens of crown, and a concave of flint glass. His
son afterwards, in 1765, constructed the triple object-glass, having a
double concave lens of flint glass in the middle of two double convex
lenses of crown glass. The right of Dollond to the invention has been
attacked by various foreign writers, but the point seems to have been
decided in his favour by the general consent of later times. His conduct
certainly appears more philosophical than that of either of his
opponents. So long as he believed that Newton’s experiment was correct,
he held fast by it, not allowing any mathematical reasoning to shake his
belief, and in this respect he was more consistent than Euler, who seems
to have thought that an achromatic combination might be made out of the
joint belief of an experiment, and of an hypothesis utterly at variance
with it. And the manner in which the distinguished philosopher just
mentioned received the news of Dollond’s invention, appears singular,
considering the side which each had taken in the previous discussion.
Euler, who had asserted the possibility of an achromatic lens, against
Dollond, who appeared to doubt it, says, “I am not ashamed frankly to
avow that the first accounts which were published of it, appeared so
suspicious, and even so contrary to the best established principles,
that I could not prevail upon myself to give credit to them.” Dollond
was the first who actually resorted to experiment, and he thus became
the discoverer of a remarkable law of optics; while his tact in the
application of his principles, and the selection of his materials, is
worthy of admiration. The reputation of Dollond rests upon the discovery
of the law, and its application to the case in point; for it has since
been proved that he was not absolutely the first who had constructed an
achromatic lens. On the occasion of an action brought for the invasion
of the patent, the defendant proved that about the year 1750, Dr. Hall,
an Essex gentleman, was in the possession of a secret for constructing
achromatic telescopes of twenty inches focal length: and a writer in the
Gentleman’s Magazine for 1790, has advanced his claim with considerable
circumstantial detail. It is difficult to get any account of that trial,
as it is not reported in any of the books. At least we presume so, from
not finding any reference to it either in the works of Godson or Davis
on Patents, though the case is frequently mentioned; or in H.
Blackstone’s report of Boulton and Watt v. Bull, in which Dollond’s case
forms a prominent feature of the argument. But, from the words of Judge
Buller in the case just cited, it is difficult to suppose that the
account given by Lalande (Montucla, Histoire des Mathématiques, vol.
iii. p. 448, note) can be correct. Lalande asserts that it was proved
that Dollond received the invention from a workman who bad been employed
by Dr. Hall, and that the latter had shown it to many persons. Judge
Buller says, “The objection to Dollond’s patent was, that he was not the
inventor of the new method of making object-glasses, but that Dr. Hall
had made the same discovery before him. But it was holden that as Dr.
Hall had _confined it to his closet_, and the public were not acquainted
with it, Dollond was to be considered as the inventor.” The
circumstances connected with the discovery, particularly the previous
investigation of the phenomenon on which the result depends,
independently of the words of Judge Buller, quoted in italics, appear to
us to render the anonymous account very improbable: nor, as far as we
know, is there any other authority for it. That Dr. Hall did construct
achromatic telescopes is pretty certain; but we are entirely in the dark
as to whether he did it on principle, or whether he could even construct
more than one sort of lens: and the assertion that he, or any one
instructed by him, had communicated with Dollond, is unsupported by any
thing worthy the name of evidence. We may add, that the accounts of this
discovery, written by Dollond himself, possess a clearness and power of
illustration, which can result only from long and minute attention to
the subject under consideration.
After this great discovery, for which he received the Copley medal of
the Royal Society, Mr. Dollond devoted himself to the improvement of the
achromatic telescope, in conjunction with his other pursuits. We are
informed by G. Dollond, Esq., that his grandfather, at the latter end of
his life, was engaged in calculating almanacs for various parts of the
world; one of which, for the meridian of Barbadoes, and the year 1761,
is now in his possession.
Mr. Dollond was elected a fellow of the Royal Society in 1761. In the
same year, November 30, he was struck with apoplexy, while attentively
engaged in reading Clairaut’s Theory of the Moon, which had then just
appeared. He died in a few hours afterwards, in the fifty-sixth year of
his age. His son Peter Dollond, already mentioned, continued the
business in partnership with a younger brother; and it is now most ably
carried on by his daughter’s son, who has, by permission, assumed the
name of Dollond.
The following extract is from the memoir written by Dr. Kelly, in which
we find nothing to regret, except that so few traits of character are
related in it. Those who write memoirs of remarkable men from personal
knowledge, should remember that details of their habits and conversation
will be much more valuable to posterity, than disquisitions upon their
scientific labours and discussions, which, coming from the pens of
friends or relations, will always be looked upon as _ex parte_
statements. Had the learned author borne this in mind, we should have
been able to give a better personal account of Dollond than the
following; which is absolutely the only information relative to his
private character which we can now obtain. “He was not content with
private devotion, as he was always an advocate for social worship; and
with his family regularly attended the public service of the French
Protestant church, and occasionally heard Benson and Lardner, whom he
respected as men, and admired as preachers. In his appearance he was
grave, and the strong lines of his face were marked with deep thought
and reflection; but in his intercourse with his family and friends he
was cheerful and affectionate; and his language and sentiments are
distinctly recollected as always making a strong impression on the minds
of those with whom he conversed. His memory was extraordinarily
retentive, and amidst the variety of his reading he could recollect and
quote the most important passages of every book which he had at any time
perused.”
[Illustration]
[Illustration:
_Engraved by W. Holl._
JOHN HUNTER..
_From a Picture by Sir Joshua Reynolds
in the Royal College of Surgeons, London._
Under the Superintendance of the Society for the Diffusion of Useful
Knowledge.
_London, Published by Charles Knight, Pall Mall East._
]
[Illustration]
JOHN HUNTER.
A life and character like that of John Hunter has many claims upon the
honourable remembrance of society; the more, because, for meritorious
members of his profession, there is no other public reward than the
general approbation of good men. We look upon him with that interest
which genius successfully directed to good ends invariably excites; as
one whose active labours in the service of mankind have been attended
with useful consequences of great extent; and whose character it is
important to describe correctly, as a valuable example to his
profession.
John Hunter was the son of a small proprietor in the parish of Kilbride
in Lanarkshire, and was born February 13, 1728. His father died while he
was a child; his brothers were absent from home; and, being left to the
care of his mother and aunt, he was spoiled by indulgence, and remained
uneducated, until his natural good sense urged him to redeem himself in
some degree from this reproach. When a boy he continued to cry like a
child for whatever he wanted. There is a letter extant from an old
friend of the family, which has this curious postscript, “Is Johnny aye
greeting yet?” presenting an unexpected picture to those who are
familiar only with the manly sense, and somewhat caustic manners, of the
great physiological and surgical authority. But the influence of
feelings and opinions, proceeding from respected persons, and
accompanied by offices of affection, is powerful upon the young mind;
and the circumstances of Mr. Hunter’s family were calculated to give
such feelings their full power over such a character as his. They lived
retired, in that state of independence which a small landed property
confers on the elder members, while the young men are compelled to seek
their fortunes at a distance from home. John Hunter neglected books, but
he was not insensible to the pride and gratification expressed by every
member of the family on hearing of his elder brother William’s success,
and the pleasure which that brother’s letters gave to all around him.
These feelings made him ashamed of his idleness, and inclined him to go
to London, and become an assistant to Dr. William Hunter in his
anatomical inquiries. William consented to this arrangement; and the
subject of our memoir quitted his paternal home in 1748; certainly
without that preparation of mind which should lead us to expect a very
quick proficiency in medical pursuits. At an earlier age he had
displayed a turn for mechanics, and a manual dexterity, which led to his
being placed with a cabinet-maker in Glasgow to learn the profession:
but the failure of his master had obliged him to return home.