MACL 
which occafion he compofed and publicly defended a the- 
fis “ on the power of gravity.” After fpending a year in 
the ftudy of divinity, he quitted the univerfity, and chiefly 
refided with his uncle till the end of the year 1717. In 
this retirement he purfued his favourite researches in ma¬ 
thematics and philofophy, with the fame afliduity as he 
liad done at the univerfity ; and at other times read the 
belt claffic authors, for which he had an exceedingly good 
tafte. In the autumn of 1 717, a vacancy taking place in 
the profeflbrfliip of mathematics in the Marifhal-college 
of Aberdeen, though only nineteen years of age, he of¬ 
fered himfelf a candidate for that chair; and obtained it, 
after a comparative trial of ten days with a very able 
competitor. His election to this oolt was a molt happy 
event for the univerfity ; as he foon revived the tafte for 
mathematical learning, and raifed it higher than it had 
ever exifted in. that feminary. In the vacation of the 
year 1719, Mr. Maclaurin paid a vifit to London, with 
the view of improving himfelf, and of being introduced 
to the illuftrious men in that metropolis. There his me¬ 
rits procured him the acquaintance of Dr. Hoadly, bilhop 
of Bangor, Dr. Samuel Clarke, and feveral other eminent 
characters; particularly fir Ifaac Newton, whofe friend- 
fliip he ever afterwards efteemed the greateft honour and 
happinefs of his life. During this vifit, he was chofen a 
fellow of the Royal Society ; and he publjflied his Geo- 
metria Organica, with the approbation of their prefident. 
In this work he treats of the defcription of curve lines 
by continued motion, and furnilhes the mathematical (In¬ 
dent with many curious theorems. On a fecond vifit to 
London, in 1721, he became acquainted with Martin 
Foikes, afterwards prefident of the Royal Society, with 
whom he maintained an intimate friendlhip and cerref- 
pondence as long as he lived, communicating to him all 
his views and improvements in the fciences. 
In the year 1722, lord Polwarth, plenipotentiary of the 
king of Great Britain at the congrefs of Cambray, en¬ 
gaged Mr. Maclaurin to accompany his eldeft fon, who was 
on the point of fetting out on his travels, in the capacity 
of tutor. After a fliort flay at Paris, and vifiting fome 
other towns in France, they fixed in Lorraine; where, 
befides the advantage of a good academy, they had that 
of the converfation and manners of one of the moll po¬ 
lite courts in Europe. It was here that Mr. Maclaurin 
wrote his piece “On the Percuflion of Bodies,” which 
gained the prize of the Royal Academy of Sciences for 
1724; and of which the l'ubftance is infected in liisTrea- 
tife of Fluxions. Having fpent the appointed time at 
Lorraine, Mr. Maclaurin and his pupil had proceeded fo 
far on their tour as the fouth of France, when the young 
gentleman was feized with a fever, which proved fatal to 
him at Montpelier. This event filled Mr. Maclaurin with 
the moll pungent grief, and determined him immediately 
to return to his profefforfhip at Aberdeen. The fame of 
his genius and abilities was now widely extended ; and 
rendered fome of the curators of the univerfity of Edin¬ 
burgh delirous of engaging him to fupply the place of 
Mr. James Gregory, who by age and infirmities was be¬ 
come incapable of teaching. There were difficulties, 
however, to furmount, which for fome time retarded this 
delign ; particularly, the competition of a gentleman emi¬ 
nent for his mathematical knowledge, who had good in- 
terell with the patrons of the univerfity; and the want 
of a fund for the fupport of the extra-profeflor. But 
thefe difficulties were got over, upon the receipt of two 
letters from fir Ifaac Newton. In one of them addrefled 
to Mr. Maclaurin, with leave to fliow it to the patrons of 
the univerfity, that great man bore the ftrongeft teliimony 
to the qualifications of our candidate for the intended 
appointment, and exprefled warm wifhes for his election ; 
and in the other, written to the lord provoft of Edin¬ 
burgh, befides fpeaking in high terms of Mr. Maclaurin’s 
(kill in mathematics, as an encouragement to him to ac¬ 
cept of the place of afliftant to Mr. Gregory, he offered 
to contribute twenty pounds per annum towards a pro- 
A U R I N. 4? 
vifion for him, till the mathematical chair fliould become 
vacant. 
Mr. Maclaurin was introduced into the univerfity of 
Edinburgh in November 1725; as was at the fame time 
his learned colleague and intimate friend, Dr. Alexander 
Monroe, profeffor of anatomy. After Maclaurin had en¬ 
tered on his new appointment, the mathematical claffe 3 
foon became very numerous, there being generally more 
than a hundred ftudents who attended his leftures every 
year; and, as thefe were of different (landings and profi¬ 
ciency, he was obliged to divide them into four or five 
claffes, to each of which he dedicated a full hour every 
day, from the firft of November to the firft of June. Ia 
the firft or lowed clafs, (ometimes divided into two, he 
taught the firft fix books of Euclid’s Elements, plain trigo¬ 
nometry, prabfical geometry, the elements of fortification, 
and an introduction to algebra. The fecond clafs ftudied 
algebra, the eleventh and twelfth books of Euclid, fpheri- 
cal trigonometry, conic fe£tions, and the general principles 
of aftronomy. The third proceeded in aitronomy and per- 
fpeftive, read a part of Newton’s Principia, and attended 
a courfe of experiments for illuftrating them ; and after¬ 
wards had the elements of Fluxions read and demonftrated 
to them. Thofein the fourth clafs read a fyftetn of flux¬ 
ions, the doftrine of chances, and the remainder of the 
Principia. Mr. Maclaurin’s lectures on thefe different 
fubjefts were delivered with fuch perfpicuity of method 
and language, that he feldom was under any neceffity of 
repeating his demonftrations; but, fo great was his anxiety 
for the improvement of his pupils, that, if at any time, 
they feemed not fully to comprehend his meaning, he 
would refume the demonftration in fome other method, 
to try if, by laying it before them in a different light, he 
could give them a better view of it. Befides the labours 
of his public profefiion, he had frequently many other 
employments and avocations. If an uncommon experi¬ 
ment was faid to have been made any where, the public 
were defirous of having it repeated by Mr. Maclaurin. 
If an eclipfe or comet was to be obferved, his telefcopea 
were always in readinefs. The ladies too would fome- 
times be entertained with his experiments and obferva- 
tions, and were altoniftied to find how eafily and familiarly, 
he could refolve the queftions which they put to him. 
His advice and afliftance, efpecially to the young gentle¬ 
men who had been his pupils, were never wanting ; nor 
was admittance refufed to any, except in his teaching- 
hours. The ingenious of all ranks, likewife, were fond 
of his company, and took up much of his time. But, 
notvvithftanding thefe employments and interruptions, I13 
continued to purfue his ftudies with the uimoft afliduity; 
for which purpofe he was under the neceffity of breaking 
in upon the ordinary hours of deep, to a degree that con¬ 
tributed greatly to impair his health. 
In the year 1733, Air. Maclaurin, who was formed for 
fociety as well as contemplation, married Anne, daughter 
of Mr. Walter Stewart, folicitor-general to king George I. 
for Scotland ; by whom he had ieven children, of whom 
two Cons and three daughters, together with his wife, fur- 
vived him. In the year 17345 Dr. Berkley, bilhop of 
Cloyne, publifhed a treatife entitled The Analyft; ia 
which he took occaflon, from fome difputes which had 
arifen concerning the fluxionary method, to explode the 
method itfelf, and alio to charge mathematicians in gene¬ 
ral with infidelity in religion. This accufation, in which 
Mr. Maclaurin confldered himfelf to be included, he 
thought it his duty to repel; and, accordingly, began aa 
anfwer to Berkley’s book. As lie proceeded, however, 
other anfwers came out, which rendered any immediate 
reply from himfelf unneceffary ; and at the fame time, fo 
many difcoveries, fo many new theories and problems, oc* 
curred to him, that, inllead of a vindicatory pamphlet, 
his work came out a complete Treatife of Fluxions, with 
their application to the moil confiderable problems in geo¬ 
metry and natural philofophy. This work was published 
at Edinburgh in 174a, in two volumes quarto 3 and, as it 
colfa 
