[ 377 ] 
And the other termJ 
are 7 . ♦?. 139 . 1393 . y,. 
5 29 169 985 
To find - fuch as makes bb — i — acc . i. c. acc 4 - 
c 1 
I = 55 , recourfe muft be had to Lord Brouncker’s 
method in Dr. Wallis’s Commercium Epiftolicum. 
LVII. Obfervations upon the Eic&ricity of the 
Air, made at the Chateau de Maintenon, 
during the Months of June, July, and Oc- 
tober, 1753 ; being Part of a Letter from 
the Abbe Mazeas, F.R.S. to the Rev. Ste- 
phen Hales, D. D. F. R . S. Tranfated 
from the French by James Parfons, M.D. 
F. R. S. 
S I R, 
Read Dec. 20, TQ EING afiured, that the electricity 
*75 3 - of the atmofphere would yet afford 
means of entertaining you, I lpent part of this film- 
mer in obferving what nature prefented me upon fo 
important a fubjeCt. 
On the 14th of June I accompanied the Marechal 
de Noailles to his cafile of Maintenon. At my ar- 
rival, I fet up an apparatus, which confided of an 
iron wire 370 feet long, raifed to 90 feet above the 
horizon. It came down from a very high room in 
the cafile, where it was faftened to a filken cord fix 
B b b feet. 
