MAC 
working of mines, the improvement of manufactures, the 
conveying of water, or the execution of any other public 
works, Mr. Maclaurin was always ready to refolve it. He 
was likewile employed to terminate fome difputes of con- 
fequence, which had arifen at Glafgow concerning the 
gauging of vefl’els; and, for that purpofe, prefented to the 
commilfioners of excife two elaborate memorials, contain¬ 
ing rules by which the officers afterwards a£ted, with 
their demonftrations. He alfo made calculations rela¬ 
tive to that wife and humane provifion which is now elta- 
blilhed by law, for the children and widows of the Scotch 
clergy, and of the profeffors in the univerfities ; entitling 
them to certain annuities and fums ? upon the voluntary 
annual payment of a certain fum by the incumbent. On 
the contrivance and adjuftment of this fcheme, Mr. Mac¬ 
laurin bellowed great labour, and contributed not a lit¬ 
tle towards bringing it to perfection. To find that his 
knowledge rendered him thus eminently ufeful, even to 
late polterity, muff have been a delightful enjoyment. 
Hut what (till more endeared his ftudies to him, was the 
site they are of in demonftrating the being and attributes 
of the Almighty Creator, and eltablifhing the principles of 
natural religion on a folid foundation. To this ufe Mr. 
Maclaurin frequently applied them; and he was equally 
zealous in the defence of revealed religion, which he 
would warmly undertake whenever he found it attacked, 
cither in co.nverfation or writing. How firm his own per- 
fiuafion of its truth was, appears from the fupport which 
it afforded him in his laft hours. 
Among Mr. Maclaurin’s productions, befides the arti¬ 
cles already fpecified, was a paper fent in to the Royal 
Academy of Sciences at Paris, in the year 17+0, on ac¬ 
count of which he lhared the prize of the academy with 
the celebrated D. Bernouilli and Euler, for refolving the 
problem relating to the motion of the tides, from the 
theory of gravity; a queftion which had been given out 
during the former year, without receiving any lolution. 
■His contributions to the Philofophical TranfaCtions may 
be feen in the different volumes of thofe collections from 
JM° 356 to N° 471, both inclufive ; and are on the follow¬ 
ing lubjeCts : Of the ConftruCtion and Meafure of Curves; 
A New Method of defcribing all Kinds of Curves; On 
Equations with impoflible Roots ; On the Defcription of 
Curves, with an Account of farther Improvements, &c. 
An Account of the Annular Eclipfe of the Sun at Edin¬ 
burgh, January 27th, 1742-3 ; A Rule for finding the 
Meridional Parts of a Spheroid with the fame exaCtnefs as 
of a Sphere ; and Of the Bafes of the Cells wherein the 
Bees depofite their Honey. Thefe papers conclude the 
lilt of our author’s writings which were publilhed during 
his life-time. After his death, the friends to whofe judg¬ 
ment lie fubmitted the difpofal of his MSS. gave directions 
for publilhing his Treatife of Algebra, and his Account 
ot Sir Ifaac Newton’s Philofophical Difcoveries. The firlt 
of thefe works, which appeared in 1748, though it had 
not the advantage to be finifhed by his own hand, is yet 
allowed to be excellent in its kinds; containing, in one 
-volume oCtavo, of a moderate lize, a complete elementary 
treatife on the fcience of Algebra, as far as it has been hi¬ 
therto carried. Subjoined to it, by way of appendix, is a 
Latin traft De Linearum Geometricarum proprietatibus 
generalibus; which appears to have been, in our author’s 
judgment, one of the beft of his performances, and on 
which he employed fome of the lateli hours that he could 
give to fuch ftudies, revifing it for the prefs, as his laft 
legacy to the fciencesand to the public. Mr, Maclaurin’s 
« Account of Sir Ifaac Newton’s Philofophical Dii'co- 
veries,” which was firlt publifhed in 1748, in quarto, and 
two years afterwards in oCtavo, originated in the follow¬ 
ing manner : Upon the death of that great man, in the 
year 1728, his nephew, Mr. Conduitt, propofed to pub- 
lifh an account of his life, and requefted Mr. Maclaurin’s 
affiffance. This the latter, out of gratitude to the me¬ 
mory of his great benefactor, cheerfully promiled, and 
jopn finilhed the hiftory of the progrefs which jxhiloiophy 
Voi.. XIV. No. 956. 
A C 49 
bad made before fir Ifaac’s time. That hiftory, which 
met with the approbation of fome of the beft judges in 
London, to whom the maiiufcript was fhown, was the firlt 
draught of this “ Account.” But, Mr. Conduitt’s death 
having prevented the execution of his part of the propofed 
life, Mr. Maclaurin’s manufcript was returned to him, 
and received confidernble additions and alterations, till it 
arrived at the ffate in which it was given to the public. 
Such was the life of this eminent perfon, fpent in a 
courfe of laborious ffudy; in continually endeavouring to 
be ufeful ; in improving curious and ufeful arts, and pro¬ 
pagating truth, virtue, and religion, amonglt mankind. 
“ He was,” fays his biographer, “ taken from us at an age 
when he was capable of doing much more; but has left 
an example, which will be long admired and imitated, till 
the revolution of human affairs puts an end to learning- 
in thefe parts of the world ; or the ficklenefs of men, and 
their fatiety of the belt things, have fubftituted for this 
philofophy fome empty form of falfe fcience; and, by the 
one or the other means, we are brought back to our ori¬ 
ginal (late of barbarity.” Life of the Author , prefixed to the 
work lafi mentioned. 
MACLAU'RIN (John, Lord Dreghorn), fon of the 
above, born at Edinburgh in December 1734, was edu¬ 
cated at the grammar-fchool of Edinburgh, and after¬ 
wards went through an academical courfe at the univer- 
fity of that city. He was admitted a member of the fa¬ 
culty of advocates at Edinburgh in 1756. In 1782, a 
Royal Society was eftablifhed at Edinburgh, of which 
Mr. Maclaurin was one of the original conltituent mem¬ 
bers ; and at an early period of the inltitution he read an 
Effay to prove that Troy w3s not taken by the Greeks. 
In 1787, he was railed from the Scottifh bar, at which he 
had praCtifed long and fuccefsfully, to the bench, by the 
title of Lord Dreghorn. He died in 1796. As an author 
he wrote, x. An Effay on Literary Property. 2. A Col¬ 
lection of Criminal Cafes. 3. An Effay on Patronage;- 
and fome poetical pieces. Befides which, we have, in the 
dramatic line, alcribed to him, 4. Hampden. 5. The 
Public. 6. The Philofopher’s Opera. During the years 
i79 3 > 3 > 4> and 5, lord Dreghorn kept a journal, or diary, 
in which he recorded the various events that happened in 
Europe during thofe years. From this journal he made a 
feleftion for publication ; and in 1799, a (election of his 
lordfhip’s works was printed in two vols. 8vo. Biog. Dram. 
MA'CLE, fi. a remarkable mineral which has hitherto 
been found only cryllallized; but its forms are very dif¬ 
ferent from thofe of all other mineral fubltances we are ac¬ 
quainted with, and not eafily determinable. It is gene¬ 
rally found in long ilightly-rhoinboidal prifms of a yel- 
Jowifli, reddifli, or greenifh, colour; each prifm is appa¬ 
rently produced by four tabular or prifmatic cryftals, ex¬ 
ternally ftraight and more or lefs exaftly joined, internally 
more or lefs feparated from one another; the fpace thus 
left in the centre of the prifm, and varying both in form 
and extent, is filled up with a black or bluifh-black fub- 
ftance; whence a tranfverfe fe&ion of the complete prif. 
matic cryffal reprefents a black nucleus, generally of a 
fiightly-rhombic figure, from each angle of which a black 
line runs towards the oppofite angle of the external fub- 
ftance, producing a kind of crofs, more or lefs dilated in 
the centre, and generally equally dilated at its four extre¬ 
mities. Sometimes the lame black diagonal lines branch 
out into other lines. In the narrow prifmatic variety, the 
black fubfiance forms by far the principal part, appearing 
in the form of a prifm, enclofed in a thin cafe of the fame 
form, and of a yellowifh-white colour. The black rhom¬ 
bic figure in the centre of the horizontal feCtion of the 
cryftals appears at firlt fight to belong to a prifm ; but it 
is generally the feftion of a pyramid, as is manifeited by 
the increaiing or diminifhing fize of the rhombic fpot, ac¬ 
cording as the tranfverfal lections are made nearer to one 
or to the other extremity of the cryffal. The cryftals are 
generally middle-fized, lometimes very narrow and acicu- 
iar ; they lometimes adopt a cylindrical form. Fracture 
O more 
