[ 4^3 ] 
In the year 1719, Dr. Pound and his nephew, 
that illuStrious aitronomer, Mr. Bradley, did, when 
Mars was in opposition to the Sun, demonstrate (to 
uie the words of Dr. Halley, Phil. Tranf. N°. 366, 
p. 1 14.) the extreme minutenefs of the Sun’s paral- 
lax, and that it was not more than 1 2", nor lefs than 
9", upon many repeated trials. At the fame time and 
by the fame kind of obfervations Mr. Maraldi deter- 
mined this parallax to be 10 the refult of his ob- 
fervations agreeing exactly with thofe deduced from 
the correspondent obfervations by Mr. Richer at Cay- 
enne and by Mr. Caffini at Paris in the year 1672. 
The voyage which the Abbe de la Caille undertook, 
to perfect a catalogue of Some of the principal fixt 
Stars, furnished the aflronomers with the means of 
determining the Sun’s parallax by corresponding alti- 
tudes of the planets Mars and Venus, to be oblerved 
on each fide of the equator, with all the accuracy of 
which that method is capable. The aflronomers 
here in Europe were invited to determine the distances 
of the planets from particular Stars on Stated days, 
while the Abbe himfelf propofed to make the corres- 
ponding obfervations on the fouthernmoSt part ot 
Africa at the Cape of Good Hope. By the differences 
of the altitudes of the northern limb of Mars and 
of fuch Stars as were nearly in the fame parallel ob- 
ferved on the fame day at the Cape with a lextant of 
6 f. radius ; at Greenwich by Dr. Bradley with a 
mural quadrant of 8 f. ; at Bologna in Italy by M. 
Zanotti with a fimilar instrument of 5k; at the Royal 
Obfervatory at Paris by Meflieurs Cafhni de Thury 
and Gentil with a moveable quadrant of 6 f. *, and in 
Sweden by Meffieurs Wargentiri, Stronmer and 
Schem- 
