( ) 
pen to confpire the fame Way, the Refult of all to- 
gether may poflxbly be greater than the whole Paral- 
lax found. Upon the whole, he makes the Horizon- 
tal Parallax of Fenus at that Time to have been, 24" 
20'", and that of the Sun 14" 18''^ : but as he takes no 
Notice of the Latitude of the Place in deducing the 
Horizontal Parallax from that of right Afcenfion , 
they both ought to be encreafed on that Account by 
about f, or in Proportion of 3 to 4. If therefore 
there be no other Miftake in his Numbers, the Ho- 
rizontal Parallax of the Sun, as deduced from his Ob- 
fervations, (hould be about 19". 
He concludes with giving fome Cautions to thofe 
who may attempt hereafter to repeat thefe Obfervati- 
ons, both in Regard to the Time proper for it, and the 
Choice and Conftitution of the Telefcope to be made 
ufe of. For greater Eafe of the Obferver, there is at 
the End a double Table, containing the Heliocentric 
and Geocentric Motions of Fenus for eight Years ; 
after which Space of Time, the Earth and FennSrit- 
turn very nearly to the fame Situation. In this Table 
he fays are marked the molt convenient Times for ob- 
ferving \ but thefe Marks, by fome Overlight, are omit- 
ted in the Table. 
For a Telefcope of 100 Roman Palms he allows an 
Aperture of 3 or 4 Inches of that Palm, with anEye- 
glafs whofe focal Length may be from 7 to 1 1 of 
the fame, but what he direds in longer Inftruments 
to increafe the Breadth of the Aperture and focal Length 
of the Eye-glafs in the fame Proportion with the In- 
ftrument, muft certainly be the EfFed of fome Mi- 
ftake : For in this Cafe, a longer Telefcope will mag- 
nify no more than the * ftiorter, but only have the 
* Strength 
