C 554 ] 
mium L non aperiatur, adeoque aer in flatu com- 
preffionis maneat, aperto tunc C et E, ventus per E 
prorumpet, celeritate, qua 78 pedes in minuto fe- 
cundo conficeret. Hinc ros, congelationi proximus, in 
grandinem, et ad fuperficiem pilei, in glaciem, com- 
pingitur : non differt vero grando a glacie, nifi figura 
rotundiore, frequenti collilione acquilita, et interdum 
nive intermixta. 
Hasc perantiqua congelationis theoria mihi quidem 
abunde fufficere videtur omnibus phaenomenis expli- 
eandis, ut eleCtricitate vel alia quadam novitate non 
indigeat. 
XCII. An Account of a remarkable Marine 
Production : hi a Letter to the Reverend 
Thomas Birch, D. D. Secretary to the 
Royal Society, from Alexander Ruflell, 
M. D. Phyfician to St. Thomas’s HofbitaL 
and F. R* S. 
S I R, 
Read June 24, 7 \ /TY ingenious friend Dr. James Naf- 
myth, having been fo kind as to 
fend me a marine production, which appears to be 
lingular, I thought fome account of it would not be 
unacceptable to the Royal Society. I have therefore 
troubled you with the inclofed papers, containing an 
extraCt of Dr. Nafmyth’s letter j a defcription of the 
body, as it appeared upon the joint examination of 
Dr. Solander, Mefiieurs Peter Collinfon, John Ellis, 
. - and 
