316 
aftronomers might likewife be deceived by 
the confident affertions of St. Pierre. I 
have troubled you with what I conceive 
to be a fatisfactory confutation of them. 
In order to fet afide truths which the 
immortal Newton brought to light, and 
which the concurring wifdom of fucceed- 
ing times have eftablithed, St. Pierre brings 
forward what he is pleafed to call a figure, 
but which is a mere axiom, and takes 
much pains to fhew, that of two figures, 
One containing the other, the figure con- 
tained muft be the fmalleft; and if the 
whole is fmailer, the parts muk likewife 
be fmaller! Can we wonder that fuch 
weapons glance from the impregnable ar- 
movr of Newton, and fall harmlefs and 
unnoticed to the ground ? St. Pierre might 
by reading have informed himfe!f that he 
was wrong in the beginning. Fer what 
he cails the known art of the meridian is 
not a firi& fegment of a circle of the 
fame fize as the equator; or, in other 
words, a degree of latitude at the equator 
is not equal to a degree of longitude on 
the equator, but is {maller—the meridian 
being an ellipfe. 
The degrees of latitude on the earth are 
meafured by the apparent motion of a fix- 
ed friar caufed by the rea! motion of an in- 
habitant ; the ftar moving an equal num- 
ber of degrees in a contrary direction, and 
ferving as an index to his motion. All 
circles have an equal number of degrees— 
were there no curvature ef furface there 
would be no degrees at all; and the more 
abrupt the curve, the fmaller the degrees, 
becaufe-it is the fegment of a fmaller 
circle. A meridian (or -any ellipfe) may 
be conceived to be formed of the fegments 
of various circles blended into eachother. 
The inhabitant has a decided method of 
finding whether he is on the fegment of a 
larger or fmaller circle, by meaiuring the 
length of a degree. The degrees of lati- 
tude about the pole are larger than at the 
equator, the meridian is confequently more 
depreffed at the poles, and more curved at 
the equator; and confequently the «qua- 
torial diameter of the earth is greater than 
the polar diameter. Let the annexed very 
fimple figure rudely reprefent the earth : 
Jet N be tbe north pole, E the equator, 
and P the regions about the polar circles : 
Jet the arc P N P beninety degrees of the 
fegment of a circle, whofe centre would be 
at A, and let PE P be likewife ninety de- 
grees of the arc of a fmailer circle whole 
centre would be at B. 
Afirenomical Error of St. Pierre. 
[ Nov. 1, 

Now it is evident that the arc P N P is 
larger than the arc P E P, the degrees 
Jarger, and the furface more depreficd, 
which is all this figere pretends to de- 
monftrate. An accurate delineation of 
the exact figure of the earth, with the de- 
grees graduaily diminifhing from the equa- 
tor tothe pole, would be very ecmplex. 
The above is fufiicient to demonftrate St. 
Pierre’s error. I thall not urge the evi- 
dence of this fhape of the earth from the 
known laws of centrifugal motion, but 
refer my reader to any philofophical or 
aftronomical work. 
St. Pierre’s theory of the tides is equally 
abiurd.. He fuppofes that the fun and 
moon melt the ices at the poles. In this 
cafe, the tides caufed by the fun would be 
greater and higher than thofe cauled by 
the moon, which ts not the cafe. And in 
fummer, the fun confiantly melting the 
ices of the north pole, would caufe an une 
remitted fummer {pring-tide to the north- 
ern hemifphere, which does not exift. Be- 
fides philofophers have never been able to 
obtain a particie of heat from the moon, 
even with the moft powerful burning 
giaffes, and in regions where the is moit 
vertical. 
St. Pierre is equally miftaken in his at« 
tempt to account for the earth preferving 
its parallelifm of axis, by the attraction of 
the fun on the accumulated ices of the 
poles, which are alternately rendered lighter 
than each other by melting and freezing ! 
Does he account for the parallelifm of Sa- 
turn’s ring in the fame manner? But the 
fact is, there is no reafon why the planets 
fhould wot preterve their parallelifm unleis 
they were heavier on one fide than another, 
which is fuppofed to be the cafe with fa- 
tellites, which therefore always prefent 
the fame fide to their primary. 
Iam, Sir, Your's, &c. ; 
C. 
‘To 
