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XLI. Introduction to the following Observa- 
tions , made by M effete rs Charles Mafon 
and Jeremiah Dixon, for determining the 
Length of a Degree of Latitude , in the 
Provinces of Maryland and Pennfyl vania, 
in North America ; by the Reverend Ne- 
vil Mafkelyne, B. D. F. R. S. Aftronomer 
Royal. 
Read Nov. 2+, lV /T ESSIEURS Charles Mafon and 
1V1 Jeremiah Dixon, who obferved the 
laft tranfit of Venus over the fun, at the Cape of Good 
Hope, under the direction of the Royal Society, had 
been fince engaged, by the Right Honourable Lord 
Baltimore and the Honourable Mr. Penn, to fettle 
the limits between the provinces of Maryland and 
Pennfylvania, in North America j which they per- 
formed partly by trigonometrical, and partly by agro- 
nomical obfervations. 
In the courfe of this work, they traced out and 
meafured fome lines lying in and near the meridian, 
and extended, in all, fomewhat more than ioo miles > 
and, for this purpofe, the country in thefe parts be- 
ing all over-grown with trees, large openings were 
cut through the woods, in the direction of the lines, 
which formed the ftraighteft and moft regular, as 
well as extenfive viftos that, perhaps, ever were 
made. 
Meflieurs 
