VARIGNON. 
being owing to some disorder or infection 
in tlie juices, which stains the natural com- 
plexion or verdure of the plant. The fourth 
kind is that called the yellow edge. 
VARIGNON (Peter), in biography, 
was born at Caen'in 1654. He was the son 
of an architect, and intended at an early 
age for the church. Accident threw into 
his way a copy of Euclid’s Elements, which 
gave him a strong bias towards mathemati- 
cal learning. So intent was he in the pur- 
suit of science, that he abridged himself of 
the necessaries of life, to purchase books to 
aid him in the pursuit. From his relations 
he met with much opposition, because they 
imagined that geometry and algebra would 
ill accord with the course of theological 
studies. While he was at college, he be- 
came acquainted with the Abbd St. Pierre ; 
and in their application to learning they 
were mutually serviceable to one another. 
The abbd, to enjoy more of Varignon’s 
company, determined to lodge with him, 
and sensible of his merit, he resolved to 
give him a fortune, that he might fully pur- 
sue the bent of his genius, and improve his 
talents; and out of only 1800 livresa year, 
which he had himselt) he conferred 300 of 
them upon Varignon. 
The abb6, persuaded that he could not 
do better than go to Paris to study philoso- 
phy, settled there in 1686, with M. Varignon, 
in the suburbs of St. Jacques. There each 
studied in his own way ; the abbd applying 
himself to the study of men, manners, and 
the principles of government; whilst Varig- 
non was wholly occupied with the mathe- 
matics. 
“ I,” says Fontenelle, “ who was their 
countryman, often went to see them, some- 
times spending two or three days with 
them. They had also room for a couple of 
visitors, who came from the same province. 
We joined together with the greatest plea- 
sure. We were young, full of the first ar- 
dour for knowledge, strongly united, and, 
what we were not then perhaps disposed to 
think so great a happiness, little known. 
Varignon, who had a strong constitution, at 
least in his youth, spent whole days in study, 
without any amusement or recreation, ex- 
cept walking sometimes in fine weather. 
I have heard him say, that in studying after 
supper, as he usually did, he was often sur- 
prised to hear the clock strike two in the 
morning ; and was much pleased that four 
hours rest were sufficient to refresh him. 
He did not leave his studies with that hea- 
viness which they usually create; nor with 
that weariness which a long application 
might occasion. He left off gay and lively, 
filled with pleasure, and impatient to renew 
it In speaking of mathematics, he would 
laugh so freely, that it seemed as if he 
had studied for diversion. No condition 
was so much to be envied as his ; his life 
was a continual enjoyment, delighting in 
quietness.” 
In the solitary suburb of St. Jacques he 
formed, however, a connection with many 
other learned men ; as Du Hamel, Du Ver- 
ney, De la Hire, &c. Du Verney often 
asked his assistance in those parts of ana- 
tomy connected with mechanics : they exa- 
mined together the positions of the muscles, 
and their directions; hence Varignon learned 
a good deal of anatomy from Du Verney, 
which he repaid by the application of ma- 
thematical reasoning to that subject. 
At length, in 1687, Varignon made him- 
self known to the public by a treatise on 
new mechanics, dedicated to the Academy 
of Sciences. His thoughts on the subject 
were, in effect, quite new. He discovered 
truths, and laid open their sources. In this 
work he demonstrated tile necessity of an 
equilibrium, in such cases as it happens in, 
though the cause of it is not exactly known. 
This discovery Varignon made by the theoiy 
of compound motions, and is what this essay 
turns upon. This new treatise on mecha- 
nics was greatly admired by the mathema- 
ticians, and procured the author two con- 
siderable places, the one of geometrician 
in the Academy of Sciences, the other of 
professor of mathematics in the college of 
Mazarine, to ibis honour he was the first 
person raised. 
Varignon catched eagerly at the science 
of infinitesimals as soon as it appeared in the 
world, and became one of its most early cul- 
tivators. Severe and unreniitted study in- 
jured his health very much, and in 1705 he 
had a dangerous illness, which confined him 
to his bed many months, and the effects of 
which he did not recover for three years. 
Indeed it can scarcely be said that he ever 
perfectly regained the vigour which he had 
formerly enjoyed. He could not lay aside 
his studies, and these were deemed incom- 
patible with his health. He died in 1722 ; 
by Fontenelle he is described as an excel- 
lent man, not apt to be jealous of the tame 
of others : he was as simple ia his manners 
as his understanding was siipeiior. He was 
at the head of the French matliematicians, 
and one of the best in Europe. He was apt 
to be over hasty when a new object pre- 
