April 1.--The anniversary of the birth of the celebrated philosopher,
René Des Cartes, who was born at La Haye, in Touraine, in 1596. When a
child he was so remarkable for the anxiety he showed to know the _cause_
of every thing, that his father used to call him his young philosopher.
He entered the army when very young; and continued to serve for some
years, but zealously pursued his mathematical and other studies all the
time. An anecdote, illustrative of the extent of his acquirements under
apparently unfavourable circumstances, is given in ‘The Pursuit of
Knowledge under Difficulties.’ “He happened to be in garrison with his
regiment at the town of Breda, in the Netherlands, when, walking out one
morning, he observed a crowd of people assembled around a placard or
advertisement which was stuck up on the wall. Finding that it was
written in the Dutch language, which he did not understand (for he was a
native of Touraine, in France), he inquired of a person whom he saw
reading it what it meant. The individual to whom he addressed his
inquiries happened to be the Principal of the University of Dort, a man
of distinguished mathematical attainments; and it was with something of
a sneer that he informed the young officer, in reply to his question,
that the paper contained the announcement of a difficult geometrical
problem, of which the proposer challenged the most able men of the city
to attempt the solution. Not repulsed, however, by the tone and manner
of the learned Professor, Des Cartes requested to be favoured with a
translation of the placard, which he had no sooner received than he
calmly remarked that he thought he should be able to answer the
challenge. Accordingly next day he presented himself again before
Beckman (that was the name of the Professor) with a complete solution of
the problem, greatly to the astonishment of that distinguished person.”
At last Des Cartes left the army, and travelled through a great part of
Europe, visiting England among other countries. He then fixed his
residence in Holland, where he wrote the greater number of his works.
They relate to metaphysics, geometry, and various departments of natural
philosophy. He is now principally remembered for the impulse which his
works gave to the study of metaphysics in Germany, and for his ideas
being now, in a great degree, the foundation of what is called the Ideal
School of Philosophy, as opposed to the Sensual, or Material. His
celebrated axiom was “_Cogito ergo sum_,” (I think, therefore, I exist).
His astronomical speculations were very singular and extravagant. He
explained the constitution of the heavens by means of a multitude of
vortices, or elementary whirlpools, of which the sun and every other
fixed star, according to him, had one, forming as it were its system,
and supporting and keeping in motion the other lighter bodies that
circle round it. Notwithstanding these fancies, Des Cartes was a most
profound and ingenious mathematician; and the science of optics is also
greatly indebted to him. Having been invited by Christina, Queen of
Sweden, to take up his residence in Stockholm, he repaired to that
capital in 1648; but died there of an inflammation of the lungs on the
11th of February, 1650, in the fifty-fourth year of his age.
April 1.--_All-Fools’-Day_, like many other days that were once observed
by most people, has no honours now but in the gaiety of school-boys. The
old custom of sending individuals on this day on a fool’s errand is not
peculiar to England. Scotland has her _April gowk_, and France her
_Poisson d’Avril_ (April fish). It is probable that the custom is a
relic of a high and general Pagan festival, in which the wildest spirit
of frolic expressed the universal gladness. It is to be remembered that
the year anciently began about the time of the vernal equinox, when the
awakening of all the powers of nature from their wintry sleep--the
leafing of trees, the budding of flowers, and the singing of birds--made
men look forward with joy to a season of long days and sunny skies. In
simple ages rough jokes, given and taken without feelings of unkindness,
form one of the most usual expressions of hilarity. There is a festival
amongst the Hindoos, called the _Huli_, which is held in March, in
honour of the new year, in the observance of which the practice of
sending persons on errands which are to end in disappointment, forms a
prominent feature. This circumstance would show that the custom, which
still remains with us, is one which has its origin in remote ages, and
is derived from a common source, accessible alike to the Hindoo and the
Briton.
April 2.--On this day, in the year 1578, was born at Folkstone, in Kent,
Dr. William Harvey, the discoverer of the circulation of the blood.
Harvey published this important discovery in 1620. Before this time it
was universally believed that the arteries, or vessels through which the
blood flows from the heart, did not contain blood at all, but only air;
and, indeed, the word artery was originally used to signify the
windpipe, and an air-tube. The body, it was thought, was fed with blood
entirely through the veins, which carried it at last to the heart, where
it was in some way or other absorbed or drunk up. Thus, one of our old
poets, Phineas Fletcher, in a curious allegorical poem, descriptive of
the body and mind of man, which he entitles ‘The Purple Island,’ written
(although not published) before Harvey announced his discovery, gives
the following account of the manner in which the body is watered and
fertilized by the different channels that pervade it:--
“Nor is there any part in all this land,
But is a little isle; for thousand brooks
In azure channels glide on silver sand;
Their serpent windings and deceiving crooks,
Circling about and watering all the plain,
Empty themselves into the _all-drinking main_,
_And creeping forward slide, but ne’er return again_.”
Nobody imagined that there was any _circulation_ of the blood, till
Harvey demonstrated that the same blood which the veins brought _to_ the
heart the arteries immediately carried away again _from_ it. Harvey
lived for many years to enjoy the glory of this discovery; dying at
Hampstead, in Essex, on the 3d of June, 1658, in the eighty-first year
of his age.
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