Some Experiments about Freezings and the diffe- 
renee betwixt common frejh Water Ice, and that 
of Sea Water: alfo a probable Conjefture a- 
bout the Original of the Nitre of ^gypt : by Dr. 
Lifter^ Fellow of the Royal Society. 
DEcember 3d 16%/^ at Night I expofed 4 Glafle 
bottles in the open aire upon the ground to freeze', 
viz, ot the l{ed' Natron Water from j£^ypt; of a ftrong 
Solution oiNitrurrf M^rarium in fair Water, of Sea Wa^^ 
tsr taken up at Scarborough and more then halfe Evapo- 
rated; of the Sulphur well at Knashorough^ that is, of 
natural brine evaporated to the fame height with the 
Sea Water. 
Note, that the 4 th in the morning, the Solution of 
Ni tr urn Murarium w^sh^ilkoi it Ice, but notanj of the 
reft. 
The 6 th in the morning, the bottle of Nitrum 
Murarium was moftlcey the Sulphur Water had no Ice 
that J could perceive atall in it: the iV^^row had much 
Ice at the bottom of the bottle ; ^iVidithQ Scarborough 
Water was not without flakes of Ice. 
The Icicles of the Natron were prettily figured, asi^ 
reprefented in Fig. i. the Icicles of the &<;^^^^^r were 
alio figured in oblong fquares, as in Fig : 2. andw'ere 
brittle and tranfparent. I fet the drained Icicles of Na- 
tron before the fire, which did readily enough melt& 
diflblve into water again ; this Ice was both alike fait in 
Ice and in Water, much like its Water to the taft, out 
of which it was frozen. 
In like manner having drained the Sea Water Ice, and 
expofed it before the fire ; thefe Icicles became foft and 
moift by degrees,but at length rather Evaporated, than 
quite melted away j and having taken up a good thick 
lump 
