[ 156 ] 
Though it has been remarked, that a calm always 
attends an earthquake •, no iuch thing happened now, 
a fine gale of wind blowing before and after, as well 
as during the time of, the fhock. 
The Iky was ferene, interfperfed with flying 
clouds. 
The fun, which flione very bright, immediately 
after the earthquake was furrounded by a very large 
halo, which lafted about an hour, and gradually dif- 
appeared. 
XXXI. An Account of a Treatife in Latin, 
prefented to the Royal Society , intituled , 
De admirando frigore artificiali, quo 
mercurius eft congelatus, differtatio, &c. 
a J. A. Braunio, Academiae Scientiarum 
Membro, 8cc. by William Watfon, M, D . 
R. S. S, 
To the Royal Society, 
Gentlemen, 
Read May 2 i, "'T TERY early lafl: year, we were in- 
V formed, that at Peterfburg, by the 
means of artificial cold, the mercury in thermo- 
meters had been condenfed to fo great a degree, as 
to become perfectly fixed and folid : but as this in- 
formation was received only in a loofe way, from 
the public gazettes, the opinions of philofophers here 
were fufpended, in relation to their giving credit to 
2 tliis 
