the Congelation of %uic%jihei\ 
“ perfectly free, being only covered by it as with pieces of ice ; 
“ the whole, together with the glafs, weighed fo me what above 
“ an ounce. I hung it out at a window three Tories high, 
“ upon a lmali roof facing the weft, fo that the glafs was 
freely expo fed to the north-weft; and I mixed with the fnow 
“ upon which it flood two drams more of fal ammoniac. The 
“ fnow and fal ammoniac in the glafs foon froze in the open 
“ air to a mafs like ice : no fenlible change, however, appeared 
“ in the quickfilver that evening; but at one in the morning it 
“ was found frozen folid. It had divided into two large and 
“lour imaller pieces; of the former, one was hemifpherical 
“ and the other cylindrical, each ieemingly rather above a dram 
“ in weight; the fourfmall bits might amount to half a fcruple. 
“ They were all with their flat fide frozen hard to the glafs, and 
“ no where immediately touched by the mixture; tiieir colour 
“ was a dull pale white, with a bluilh caft, like zinc, very 
“ different from the natural appearance of quickfilver. I wiftied 
“ much to break the glafs immediately, and to try how thele 
“ bodies would bear the hammer ; but defiring rather to have 
“ witnefles of fuch a rare phenomenon I refrained. The fpirit 
“ of wine, in an excellent thermometer made bv brander, 
“ flood at this time io° under o of Fahrenheit’s fcale, which 
“ was the cold of Upfal in 1740. Next morning, the 12th, 
“ about (even o’clock, I found that the larger hemifphere be- 
44 gan to melt, perhaps becaufe it was mofl expofed to the air, 
“ and not fo near as the others to the fal ammoniac mixture 
“ which lav beneath. In this ftate it refembled an amalgam, 
“ finking to that lide on which the glafs was inclined, but 
“ without quitting the furface of the glafs, to which it was 
“ ftill firmly congealed ; the five other pieces had not yet un- 
dergone any alteration, but remained frozen hard, as I had 
Y y 2 44 obferved 
