ASTRONOMER, MATHEMATICIAN, AND NATURAL SCIENTIST
The sketch of Wren’s activities at Wadham (in Chapter II) shows the
variousness of his mind, but clearly his many inventions, though they
make an astonishing list, were _juvenilia_. His contemporary Hooke said
of him, “Since the time of Archimedes there scarce ever met in one man
in so great perfection such a mechanical hand and so philosophical a
mind”; and he describes a method of determining the parallax of comets
“invented by that incomparable mathematician Dr. Christopher Wren.”
In estimating the value of such an opinion, one of very many, I am
bound to rely on the judgment of scientific friends who have generously
helped me with this chapter, because I can only repeat Professor
Lethaby’s comment on the same text: “These things are beyond my
knowledge, but I know that they represent wonderful powers.”
We shall only understand the part played by Wren in the development of
natural science if we see that development as the work of a team rather
than of individuals. Wilkins, Boyle, Lawrence Rooke, Hooke, Seth Ward,
Wallis, Scarborough, Oughtred, Wren and many another shared a common
enthusiasm for the advancement of knowledge which showed itself in
common effort. Wren was the man to whom his associates turned for help
in solving their individual problems, because of his extraordinary
ingenuity in inventing apparatus which would establish or dispel the
truth of some scientific idea, and still more because of his ready
kindness and modesty. During the early days of the Royal Society he was
not only in an especial manner the cement which kept together the whole
fabric, but the inspirer of much work which was carried to fruition by
others.
In 1645, the year when Wren invented, as a boy of thirteen, a new
astronomical instrument, the first meetings took place at which was
sown the seed from which the Royal Society sprang. Dr. Wallis, the
mathematician, Dr. Goddard, Wilkins, later Warden of Wadham, and
Sir Christopher’s father, Dr. Wren, were amongst the attendants at
weekly gatherings, when philosophy and especially natural science were
discussed.
When Wallis, Wilkins, and Goddard went to Oxford in 1648-49, the London
meetings continued, but new meetings were held also at Oxford, first
in Dr. Petty’s rooms and afterwards at the apartments of Wilkins at
Wadham. When Wilkins went to Trinity, Cambridge, the Oxford men enjoyed
the hospitality of Robert Boyle.
The London meetings were held often at Gresham College and, when Wren
was fulfilling his duties as Professor of Astronomy at the College,
after his Wednesday lectures and after Rooke’s Thursday lectures. Lord
Brouncker, the friend of Pepys, John Evelyn and others were frequently
at the meetings, and the Royal Society took formal shape, after one of
Wren’s lectures, on November 28, 1660, when Brouncker, Robert Boyle,
Rooke, Wilkins and others withdrew to Wren’s private room and decided
to constitute themselves formally as a college or society. It was after
Wren’s next lecture on December 5, 1660, that Sir Robert Moray notified
to the meeting the King’s pleasure at the constitution of the society
and his promise of encouragement.
The Society of Philosophers into which the young Wren found himself
plunged owed its inspiration above all to the writings of Bacon.
Bacon was not himself a man of science in the sense that Galileo or
even Descartes was, for he made no observations and arrived at no
discoveries in any particular branch of science. But he summed up
all the Renaissance revolt against Scholasticism, and had set forth
in a noble literary form a definite system of knowledge that could
be opposed to the so-called Aristotelianism which hitherto had held
sway over the minds of men. Bacon’s guiding principle was the appeal
to experiment, for his famous “method of induction” amounts to that.
The Scholastic writers worked by deduction. They laid down their
premisses, they worked out the laws of formal logic by which they
could draw deductions from them, and they accepted the conclusions
without enquiring whether the premisses could bear the weight of the
superstructure built upon them. Bacon opposed to this his dictum,
“hypotheses non fingo;” the business of the man of science is to
collect the facts without any preconceived theory, and to let the
facts themselves reveal the law which binds them together. Actually,
scientific discovery does not proceed in this way. Without a guiding
hypothesis the mind is lost in a wilderness of facts, but the value of
the hypothesis must be checked continually by its capacity to embrace
the known facts and to predict new ones. None the less, Bacon’s method
was at the time a necessary summons to experiment, and under its
stimulus the young men of the day attacked the problem of the natural
world about them with the enthusiasm of crusaders. For as a corollary
to his method Bacon had insisted upon the necessity of studying the
common arts and crafts hitherto regarded as beneath the dignity of
philosophy. In the operations of the mechanic or the smelter, and in
the growth of crops, were to be found the materials of science. So
the new philosophers were universally curious and their curiosity
about things was the note of the society in which Wren grew up and the
dominant feature of his own mind until he settled down to architecture.
Wren’s scientific equipment was primarily that of a mathematician, and
to this he added an inventive turn of mind, which developed first in
the construction of apparatus and was afterwards so nobly turned to
account in his building. As a man of science he touched everything
and adorned it, but he cannot be regarded as a supreme pioneer in any
particular direction, nor is his name associated with any fundamental
discovery. As mathematician he was abreast of all the knowledge of the
day; he contributed to the advancement of knowledge therein as in his
discussions of the cycloid, but even in that particular subject his
work lacks the luminous intuition displayed by Pascal. Nor did he break
fresh ground and conceive new methods which afterwards developed into
part of the fundamental texture of mathematics, as Wallis did with
his theory of infinitesimals, or as Newton did a few years later in a
larger field.
Wren’s activity at the Royal Society in the multifarious problems
which its members examined must not be allowed to obscure the fact
that, _professionally_, he was an astronomer. Gresham Professor at
twenty-five, and Savilian Professor at twenty-eight, he achieved little
that has survived. The world and his own nimble mind called him to
an excess of enterprises. In 1662, his indulgent friend Sprat wrote,
“The Vice-Chancellor [of Oxford University] did yesterday send for
me to enquire where the _Astronomy Professor_ was, and the reason of
his absence so long after the beginning of term.... _He most terribly
told me that he took it very ill_ you had not all this while given him
any account of what hindered you in the discharge of your office.”
Sprat stoutly defended Wren and urged on the angry Vice-Chancellor
that the rebuilding of St. Paul’s and the fortifying of Tangier (Wren
toyed with the latter but refused it) were of greater “concernment for
the benefit of Christendom” than “the drawing of lines in Sir Harry
Savill’s school.” It was not until 1673, however, that Wren officially
turned his back on astronomy by resigning the Savilian professorship.
The chief document of his astronomical career is his inaugural Gresham
lecture in 1657, of which Latin and English versions are printed
in _Parentalia_. A manuscript lecture, _De corpore Saturni ejusque
phasibus Hypothesis_, flits irritatingly by us as having been possessed
by one William Jones, Esquire, but after that--silence. The Gresham
oration was a little pompous and for the “politer genii” whom he espied
in his audience.
“A time would come when men would be able to stretch out their eyes
as snails do (Wren worked with a thirty-six foot glass at Oxford) and
extend them to fifty feet in length, by which means they should be
able to discover ten thousand times as many stars as we can.” Of this
Professor Hinks says, “Rather poor stuff, suddenly rising into this
most interesting conclusion--‘and find the Galaxy to be myriads of
them, and every nebulous star appearing as if it were the Firmament
of some other world ... bury’d in the vast abyss of intermundious
vacuum.’ What would we not give [Professor Hinks continues] for
fuller knowledge of what was in Wren’s mind when he wrote this
passage so strangely before its time, so strongly suggestive of the
island universe theory of spiral nebulæ to-day.” There was also the
matter of the method for constructing solar eclipses. The lay reader
may be spared bibliographical details, into which I have dived, but
Professor Hinks makes this significant comment: “Wren was the first
to discover the graphical method of computing eclipses that, with
some modifications due to much improved tables, remains by far the
most instructive, though not the most numerically accurate way of
calculating ... and is in use to-day for the graphical prediction of
occultations.”
It was a practical thought of Wren that the Monument should be used as
a gigantic telescope, and members of the Royal Society tried so to use
it, but failed, because passing coaches caused vibrations. He had a
like idea for the great south staircase at St. Paul’s, but again, for
practical reasons, it broke down.
The biographers of Wren have made great play with a story taken from
a manuscript bound up in the heirloom _Parentalia_. Miss Milman
referred to “the problem which Pascal, ... under the pseudonym of Jean
de Montfert, challenged the mathematicians of England to answer by a
certain day. He accompanied the challenge with a promise of a prize of
twenty pistoles to the successful competitor. Christopher Wren solved
the problem, but for some unexplained reason never received the prize,
while the problem from Kepler which he set in return seems never to
have been solved.” The facts are rather different. In June, 1658,
Pascal put out a challenge to all mathematicians (not English alone)
to find a solution for certain problems connected with a cycloid, the
curve described by a point on the circumference of a circle when that
circle rolls along a straight line--_e.g._, a nail on the rim of a
carriage-wheel.
In an appendix I set out the story as it has been given me by Sir
Daniel Hall. It is rather technical, but may be summed up simply.
Pascal received both attempts at solutions and replies which merely
discussed germane matters. Wren sent a partial but admirable
contribution, unfortunately “without demonstration.” It was original
as far as it went, but not the complete solution for which Pascal had
asked. Cavarci, the umpire in this high contest, wrote that Wren had
merely solved the easy part of it.
It appears clear that in withholding the prize Pascal wronged neither
Wren nor the other contestants. The suggestion that Wren was the master
mathematician of Europe will not do. It is enough to affirm of him that
he was an ingenious geometrician who made several minor advances in
that science. He left no evidence of mathematical _genius_, a quality
which ought to be reserved to the authors of far-reaching and fruitful
conceptions. The true significance of Wren’s mathematics lies in the
fine way in which he applied them in his buildings. No one is a better
representative of applied science as compared with pure or fundamental
science. Too much has also been made of Wren’s work on the barometer.
Some enthusiasts have, indeed, tried to transfer to him the credit
which belongs to Torricelli and Pascal.
Wren repeated Torricelli’s experiment at the top and bottom of a hill,
and finding that the mercury column stood at a lower height on the
top of the hill, argued that the mercury was really balanced by the
weight of the air, or, as we now say, measured its pressure. But in
this experiment Wren was anticipated by Pascal; his experiment was
regarded by his contemporaries as made independently, but it would be
hard to say that the experiment was really Wren’s own device, so much
was the question a matter of discussion among the men of science of
the time. The enunciation of the laws of impact was made practically
simultaneously by Wallis, Wren, and Huygens. Wren’s may be regarded as
the most elegant demonstration, but it was Huygens alone who perceived
that when the colliding bodies are perfectly elastic the energy of the
system, _i.e._, the sum of the products of the mass of each of the
bodies multiplied by the square of its velocity, remains unchanged--one
of the generalisations at the base of modern science. Similarly,
although Wren became Professor of Astronomy both at Gresham College and
then at Oxford, no outstanding observation or fundamental discovery
remains attached to his name. Speaking broadly and generally we can
say that Wren was universally accomplished in all the science of the
time, that in several directions he showed a quality of mind that was
only short of the highest, and that finally he abandoned the pursuit
of pure science too soon to have accomplished in any branch such a
mass of work as would mark him as one of the founders of that science.
It must always be remembered that Wren took to architecture when he
was just over thirty, and was immersed in a huge practice when he was
thirty-five.
But perhaps Wren also was too universal. Perhaps the very ingenuity of
his mind led to distractions in too many directions. It may be, too,
that his inclinations towards the practical fusion of art, science,
and administration, which found full expression as an architect, had
always tended to draw him away from the pursuit of abstract science.
We may notice that even in the early days of Oxford he was always the
demonstrator and the contriver of experiments at the meetings of the
philosophers, and later, in the early history of the Royal Society, we
find that it was to Wren that the Society continually turned for the
solution of almost any problem that came under discussion. A letter he
wrote to Lord Brouncker in 1663, as to an appropriate show when the
King visited the Society, suggests he was already distrusting his own
skill and pleasure in experiment. “_Sciographical Knacks_ (of which an
hundred sorts may be given) are so easy in the invention, that now
they are cheap.”
The extracts from the Minute Books of the Royal Society show the
confidence of its members in Wren’s universality of mind and
constructive ability. At the second meeting of the Society on December
5, 1660, when Sir Robert Moray brought the King’s approval, “Mr. Wren
was desired to prepare against the next meeting for the pendulum
experiment.” A fortnight later the record states “that Dr. Petty and
Mr. Wren were desired to consider the philosophy of shipping ... and
that Mr. Wren bring in his account of the pendulum experiment.”
Wren was at Oxford in the Spring of 1661, and things did not go well
without him. On May 8 we find a resolution that a letter be sent
him charging him in the King’s name to make a globe of the moon
and likewise to continue the description of several insects that
he had begun. Sir Robert Moray transmitted the royal command in a
very affectionate letter. The moon was duly delivered to the King at
Whitehall, who received it with great satisfaction.
On September 4 there is reported some correspondence with Sir Kenelm
Digby and Monsieur Frenicle concerning Wren’s hypothesis about Saturn’s
rings. Later there is a letter of Wren’s which records that, although
in 1658 he had made a model to illustrate his theory of Saturn’s rings,
he had withdrawn this hypothesis as soon as he had learnt of Huygen’s
more convincing explanation.
On January 1, 1662, “Mr. Wren was requested to prosecute his design
of trying by several round pasteboards their velocity in falling.” On
the 8th Dr. Wren brought in a scheme of a weather-clock. On January
22 the pendulum experiment is described at length together with Lord
Brouncker’s calculation of the velocity of fall, and at the same
meeting it is recorded that “Dr. Wren showed his experiment of filling
a vessel with water which emptied itself when filled at a certain
height.”
On February 5 “Dr. Wren was desired to think of an easy way for a
universal measure different from that of a pendulum.” This was a
question of devising an absolute standard of length dependent upon
some natural phenomenon, which finally found expression in the metre
and again in a standard of length derived by physicists from the
wave-length of light.
On February 12 “Dr. Wren proposed blacklead as a better means than oil
for preserving the pivots of the wheels of watches and clocks from
grating or wearing out.”
On March 5 “the amanuensis was ordered to attend Dr. Wren to take
directions concerning the experiment of water in the long tube.” This
means the setting up of a water barometer, with water in place of the
mercury of Torricelli’s experiment.
On September 3, 1662, it is recorded that “it was referred to Dr.
Wren to take care of making the several experiments mentioned at the
last meetings concerning the _aquæ salientes_,” by which we are to
understand the earliest experiments on the rise of liquids in capillary
tubes. The record goes on to say, “The request of the Society made at
the last meeting to Dr. Wren about comparing the Earl of Sandwich’s
experiments was continued but it being a business of difficulty and
much calculation required more time than he could yet obtain from
his other employments.” None the less, a week later “Dr. Wren was
reminded of promoting Mr. Rooke’s observations concerning motions of
the satellites of Jupiter,” and a fortnight later still, “Dr. Wren
presented some cuts done by himself in a new way of etching whereby he
said he could almost as soon do a piece on a plate of glass as another
could draw it with a crayon on paper.” At the same meeting, too, “Dr.
Wren proposed the experiment of forcing up water in different pieces
of different diameter and different altitudes ... and was desired to
bring a description of this experiment at the next meeting....” On
October 8 of the same year “Dr. Wren offered an experiment about the
undulation of quicksilver in a crooked tube which he suggested was for
the velocity of it proportional to the vibration of a pendulum. He was
desired to prosecute the experiment and to give in an account of it.”
Sprat, in his _History of the Royal Society_, lays especial stress on a
scheme of work devised by Wren in the interests of agriculture.
“The second work (the first was the Doctrine of Motion) which he has
advanced, is the History of Seasons; which will be of admirable
benefit to mankind, if it shall be constantly pursued, and derived down
to posterity. His proposal therefore was, to comprehend a diary of
wind, weather, and other conditions of the air, as to heat, cold, and
weight; and also a general description of the year, whether contagious
or healthful to men or beasts; with an account of epidemical diseases,
of blasts, mildews, and other accidents, belonging to grain, cattle,
fish, fowl, and insects.”
Nor must we forget Wren’s anatomical and surgical experiments. In his
early Oxford days he devised instruments (fully described by Boyle)
for making injections into the blood of a dog, which he tried very
successfully (for everyone but the dog). He also skilfully removed the
spleen of another dog which “in less than a fortnight grew not only
well, but as sportive and wanton as before.”
Bound up in the heirloom _Parentalia_ is a most careful drawing
by Wren’s hand of the anatomy of the river eel. Instances of his
versatility over the whole field of science can be multiplied almost
indefinitely.
From the end of 1662 Wren’s name began to appear less frequently in
the records of the Royal Society. His increasing preoccupation with
architecture and, later, his journey to Paris provide the reason.
But these extracts do make clear that, even when he was preoccupied
with science, Wren’s energies were to some extent dissipated by
the universality of his interests and his practical skill as an
experimenter. They can be accepted as explaining why he did not become
supreme in any one branch of science, although any loss in this
direction was, perhaps, more than compensated for by the richness of
the experience and the breadth of mind that he was thereby enabled to
turn to the service of architecture.
Though architecture became an exacting mistress, he always kept in
touch with the Royal Society and, after a period as Vice-President
when he was often in the Chair, served as President in 1680. He could
not give the time to experiment, but he was an effective stimulus
in the organisation of scientific thought, and took an exceedingly
active part in discussions which ranged from comets to the making
of jessamine-scented gloves with daffodils, from Mr. Mercator’s new
projection of maps to the conclusion that “all wholesome food should
have oils” (which smacks of vitamines), from the structure of peat to
the contrivance of an azimuth compass.
The incredible boy of Wadham days had become the tireless President at
fifty, immersed in the greatest architectural practice of his century,
but still the enthusiastic scientist. I find it all very astonishing.