WILLIAM PETTY, born on the 26th of May, 1623, was the son of a clothier
at Romsey in Hampshire. After education at the Romsey Grammar School, he
continued his studies at Caen in Normandy. There he supported himself by
a little trade while learning French, and advancing his knowledge of
Greek, Latin, Mathematics, and much else that belonged to his idea of a
liberal education. His idea was large. He came back to England, and had
for a short time a place in the Navy; but at the age of twenty he went
abroad again, and was away three years, studying actively at Utrecht,
Leyden, and Amsterdam, and also in Paris. In Paris he assisted Thomas
Hobbes in drawing diagrams for his treatise on optics. At the age of
twenty-four Petty took out a patent for the invention of a copying
machine. It was described in a folio pamphlet “On Double Writing.” That
was in 1647, in Civil War time, and although Petty followed Hobbes in his
studies, he did not share the philosopher’s political opinions, but held
with the Parliament. In 1648 he added to his former pamphlet a
“Declaration concerning the newly invented Art of Double Writing.”
Samuel Hartlib, the large-hearted Pole, who in those days spent his
worldly means in England for the advancement of agriculture and of
education, and other aids to the well-being of a nation, had caused
Milton to write his letter on education, as has been shown in the
Introduction to the hundred and twenty-first volume of this Library,
which contains that Letter together with Milton’s Areopagitica. Young
Petty’s first published writing was a Letter to Hartlib on Education,
entitled “The Advice of W. P. to Mr. Samuel Hartlib for the Advancement
of some Particular Parts of Learning.” This appeared in 1648, when
Petty’s age was twenty-five, and its aim was to suggest a wider view of
the whole field of education than had been possible in the Middle Ages,
of which schools and colleges were then preserving the traditions, as
they do still here and there to some extent. This pamphlet has been
reprinted in the sixth volume of the “Harleian Miscellany.” William
Petty wished the training of the young to be in several respects more
practical.
His own activity of mind caused him to settle at Oxford, where he taught
anatomy and chemistry, which he had been studying abroad. He had read
with Hobbes the writings of Vesalius, the great founder of modern
practical anatomy. In 1649 William Petty graduated at Oxford as Doctor
of Medicine, obtained a fellowship at Brasenose, and practised. In 1650
he surprised the public by restoring the action of the lungs in a woman
who had been hanged for infanticide, and so restoring her to life.
Dr. Petty now took his place at Oxford among the energetic men of science
who had been inspired by the teaching of Francis Bacon to seek knowledge
by direct experiment, and to value knowledge above all things for its
power of advancing the welfare of man. The headquarters of these workers
were at Oxford, and in London at Gresham College.
In 1650 Petty was made Professor of Anatomy at Oxford, and it is a
characteristic illustration of his great activity of mind that he was at
the same time Professor of Music at Gresham College. Music had then a
high place in the Seven Sciences, as that use of regulated numbers which
expressed the harmonies of the created world. The Seven Sciences were
divided into three of the Trivium, and four of the Quadrivium. The three
of the Trivium concerned the use of speech; they were Grammar, Rhetoric,
and Logic. The four of the Quadrivium concerned number and measure; they
were Arithmetic, Geometry, Music; and Astronomy, which led up straight to
God. Advance to Music might be represented in the student’s mind by his
reaching to a sense of the harmonious relation of all his studies, which,
so to speak, lived in his mind as a single well-proportioned thought.
In 1652 Dr. Petty was sent to Ireland as physician to the army of the
Commonwealth. While there his active mind observed that the Survey on
which the Government had based its distribution of fortified lands to the
soldiers had been “most inefficiently and absurdly managed.” He obtained
the commission to make a fresh Survey, which he completed accurately in
thirteen months, and by which he obtained in payments from the Government
and from other persons interested ten thousand pounds. By investing this
in the purchase of soldiers’ claims, he secured for himself an Irish
estate of fifty thousand acres in the county of Kerry, opened upon it
mines and quarries, developed trade in timber, and set up a fishery.
John Evelyn said of him “that he had never known such another genius, and
that if Evelyn were a prince he would make Petty his second councillor at
least.” Henry Cromwell as Lord Deputy in Ireland made Petty his
secretary.
Petty’s Maps were printed in 1685, two years before his death, as
“Hiberniæ Delineatio quoad hactenus licuit perfectissima;” a collection
of thirty-six maps, with a portrait of Sir William Petty, a work
answering to its description as the most perfect delineation of Ireland
that had up to that time been obtained. There is a coloured copy of
Petty’s maps in the British Museum, and also an uncoloured copy, with the
first five maps varying from those in the coloured copy, and giving a
General Map of Ireland, followed by Maps of Leinster, Munster, Ulster,
and Connaught. There was afterwards published in duodecimo, without
date, “A Geographical Description of ye Kingdom of Ireland, collected
from ye actual Survey made by Sir William Petty, corrected and amended,
engraven and published by Fra. Lamb.” This volume gives as its contents,
“one general mapp, four provincial mapps, and thirty-two county mapps; to
which is added a mapp of Great Brittaine and Ireland, together with an
Index of the whole.”
At the Restoration William Petty accepted the inevitable change, and
continued his service to the country. He was knighted by Charles the
Second, and appointed in 1661 Inspector-General of Ireland. He entered
Parliament. He was one of the first founders of the Royal Society,
established at the beginning of the reign of Charles the Second; and the
outcome of these scientific studies along the line marked out by Francis
Bacon, which had been actively pursued in Oxford and at Gresham College.
In 1663 he applied his ingenuity to the invention of a swift
double-bottomed ship, that made one or two passages between England and
Ireland, but was then lost in a storm.
In 1670 Sir William Petty established on his lands at Kerry the English
settlement at the head of the bay of Kenmare. The building of forty-two
houses for the English settlers first laid the foundations of the present
town of Kenmare. “The population,” writes Lord Macaulay, “amounted to a
hundred and eighty. The land round the town was well cultivated. The
cattle were numerous. Two small barks were employed in fishing and
trading along the coast. The supply of herrings, pilchards, mackerel,
and salmon, was plentiful, and would have been still more plentiful had
not the beach been, in the finest part of the year, covered by multitudes
of seals, which preyed on the fish of the bay. Yet the seal was not an
unwelcome visitor: his fur was valuable; and his oil supplied light
through the long nights of winter. An attempt was made with great
success to set up ironworks. It was not yet the practice to employ coal
for the purpose of smelting; and the manufacturers of Kent and Sussex had
much difficulty in procuring timber at a reasonable price. The
neighbourhood of Kenmare was then richly wooded; and Petty found it a
gainful speculation to send ore thither.” He looked also for profit from
the variegated marbles of adjacent islands. Distant two days’ journey
over the mountains from the nearest English, Petty’s English settlement
of Kenmare withstood all surrounding dangers, and in 1688, a year after
its founder’s death, defended itself successfully against a fierce and
general attack.
Sir William Petty died at London, on the 16th of December, 1687, and was
buried in his native town of Romsey. He had added to his great wealth by
marriage, and was the founder of the family in which another Sir William
Petty became Earl of Shelburne and first Marquis of Lansdowne. The son
of that first Marquis was Henry third Marquis of Lansdowne, who took a
conspicuous part in our political history during the present century.
Sir William Petty’s survey of the land in Ireland, called the Down
Survey, because its details were set down in maps, remains the legal
record of the title on which half the land in Ireland is held. The
original maps are preserved in the Public Record Office at Dublin, and
many of Petty’s MSS. are in the Bodleian Library at Oxford.
He published in 1662 and 1685 a “Treatise of Taxes and Contributions, the
same being frequently to the present state and affairs of Ireland,” of
which his view started from the general opinion that men should
contribute to the public charge according to their interest in the public
peace—that is, according to their riches. “Now,” he said, “there are two
sorts of riches—one actual, and the other potential. A man is actually
and truly rich according to what he eateth, drinketh, weareth, or in any
other way really and actually enjoyeth. Others are but potentially and
imaginatively rich, who though they have power over much, make little use
of it, these being rather stewards and exchangers for the other sort than
owners for themselves.” He then showed how he considered that “every man
ought to contribute according to what he taketh to himself, and actually
enjoyeth.”
In 1674 Sir William Petty published a paper on “Duplicate Proportion,”
and in 1679 he published in Latin a “Colloquy of David with his Own
Soul.” In 1682 he published a tract called “Quantulumcunque, concerning
Money;” and “England’s Guide to Industry,” in 1686. From 1682 to 1687,
the year of his death, Sir William Petty was drawing great attention to
the “Essays on Political Arithmetic,” which are here reprinted. There
was the little “Essay in Political Arithmetic, concerning the People,
Housings, Hospitals of London and Paris;” published in 1682, again in
French in 1686, and again in English in 1687. There was the little
“Essay concerning the Multiplication of Mankind, together with an Essay
on the Growth of London,” published in 1682, and again in 1683 and 1686.
There was in 1683, “Another Essay in Political Arithmetic concerning the
growth of the City of London.” There were “Farther Considerations on the
Dublin Bills of Mortality,” in 1686; and “Five Essays on Political
Arithmetic” (in French and English), “Observations upon the Cities of
London and Rome,” in 1687, the last year of Sir William Petty’s life.
Other writings of his were published in his lifetime, or have been
published since his death. He was in the study of political economy one
of the most ingenious and practical thinkers before the days of Adam
Smith.
But the interest of those “Essays in Political Arithmetic” lies chiefly
in the facts presented by so trustworthy an authority. London had become
in the time of the Stuarts the most populous city in Europe, if not in
the world. This Sir William Petty sought to prove against the doubts of
foreign and other critics, and his “Political Arithmetic” was an
endeavour to determine the relative strength in population of the chief
cities of England, France, and Holland. His application of arithmetic in
the first of these essays to a census of the population at the Day of
Judgment he himself spoke of slightingly. It is a curious example of a
bygone form of theological discussion. But his tables and his reasonings
upon them grow in interest as he attempts his numbering of the people in
the reign of James II. by collecting facts upon which his deductions
might be founded. The references to the deaths by Plague in London
before the cleansing of the town by the great fire of 1666 are very
suggestive; and in one passage there is incidental note of delay in the
coming of the Plague then due, without reckoning the change made in
conditions of health by the rebuilding. Nobody knew, and no one even now
can calculate, how many lives the Fire of London saved.
There was in Petty’s time no direct numbering of the people. The first
census in this country was not until more than a hundred years after Sir
William Petty’s death, although he points out in these essays how easily
it could be established, and what useful information it would give.
There was a census taken at Rome 566 years before Christ. But the first
census in Great Britain was taken in 1801, under provision of an Act
passed on the last day of the year 1800, to secure a numbering of the
population every ten years. Ireland was not included in the return; the
first census in Ireland was not until the year 1813.
Sir William Petty had to base his calculations partly upon the Bills of
Mortality, which had been imperfectly begun under Elizabeth, but fell
into disuse, and were revived, as a weekly record of the number of
deaths, beginning on the 29th of October, 1603; notices of diseases first
appeared in them in 1629. The weekly bills were published every
Thursday, and any householder could have them supplied to him for four
shillings a year. These essays will show how inferences as to the number
of the living were drawn from the number of the dead. And even now our
Political Arithmetic depends too much upon rough calculations made from
the death register. It is seven years since the last census; we have
lost count of the changes in our population to a very great extent, and
have to wait three years before our reckoning can be made sure. The
interval should be reduced to five years.
Another of Sir William Petty’s helps in the arithmetic of population was
the Chimney Tax, a revival of the old fumage or hearth-money—smoke
farthings, as the people called them—once paid, according to Domesday
Book, for every chimney in a house. Charles the Second had set up a
chimney tax in the year 1662; the statistics of the collection were at
the service of Sir William Petty. The tax outlived him but two years.
It was promptly abolished in the first year of William and Mary.
The interest taken at home and abroad in these calculations of Political
Arithmetic set other men calculating, and reasoning upon their
calculations. The next worker in that direction was Gregory King,
Lancaster Herald, whose calculations immediately followed those of Sir
William Petty. Sir William Petty’s essays extended from 1682 until his
death in 1687. Gregory King’s estimates were made in 1689. They were a
study of the number population and distribution of wealth among us at the
time of the English Revolution, and the unpublished results were first
printed in a chapter on “The People of England,” which formed part a
volume published in 1699 as “An Essay upon the Probable Methods of making
a People Gainers in the Balance of Trade, by the Author of the Essay on
Ways and Means.” The volume was written by a member of Parliament in the
days of William and Mary, who desired to apply principles of political
economy to the maintenance of English wealth and liberty. It has been
wrongly scribed to Defoe; and its suggestion of the plan a trading
Corporation for solution of the whole problem of relief to the poor who
cannot work, and relief from the poor who can, might indeed make another
chapter in Defoe’s “Essay on Projects.” The chapter, which gives the
Political Arithmetic of Gregory King, with such comment and suggestions
as might be expected from a liberal supporter of the Revolution, and with
this suggestion of a Corporation, is in itself a complete essay. It
follows naturally upon the Political Arithmetic of Sir William Petty in
close sequence of time, and in carrying a like method of inquiry forward
until it reaches a few more conclusions. I have, therefore, added it to
this volume. It seems, at any rate, to show how Sir William Petty’s
books, of which the very small size grieved the stationer, had a large
influence on other minds; his figures bearing fruit in a new search for
facts and careful reasoning on the condition of the country at one of the
most critical times in English history.