[ 108 1 
earth, and as much fixed air as is contained in 2 T V 
grains of calcareous earth. 
The fame quantity of water, from the pump in 
Hanover-fquare, contains 2 grains of unneutra- 
lized earth, with as much fixed air as is contained in 
7 of earth. 
The fame quantity of water, from St. Martin’s 
Church-yard, contains 3 grains of unneutralized 
earth, with as much fixed air as is contained in 
8 of earth. 
„ , .... — ■ ' 1 - — 
Received November 18, 1766. 
XII. Defcription of a Meteor feen at Oxford, 
O&ober 12, 1766. In a Letter to 
Charles Morton, M. D. Sec . R . S. from 
the Rev. John S win ton, B. D . F. R. S . 
Meinber of the Academy degli Apatifti at 
Florence, and of the Etrufcan Academy 
of Cortona in Tufcany. 
Dear Sir, % 
Head Feb. 26, rpHE Reverend Dr. Sharp coming 
1767. - nto chrift-Church common- 
room out of the great quadrangle, on Saturday, Octo- 
ber 12, 1765, about 8 h 30' P. M. informed the com- 
pany there, that he had feen fome remarkable Aurora 
Boreales a few minutes before. But, as fuch pheno- 
mena 
