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to 530 ; and in two thermometers on the 26th, to 
6 jo. But as well in the thermometer, which he 
ufed on the 23th, as in two of the 26th, the bulbs 
were cracked in the experiment : they cohered how- 
ever; nor was the leaft part of the bulb feparated, 
but the congealed mercury feemed to adhere to all 
parts of the bulb. In the following experiments, he 
invariably found, that the mercury funk lower, if 
the whole of it was congealed, than if any part of it 
remained fluid. It then generally defcended to 6 80 
and 700, but the bulbs were never without cracks; 
moreover, it defcended to 800, and beyond even to 
1500; but in this laft experiment, the bulb w r as 
quite broke, fo that the globe of mercury, thoroughly 
frozen, fell out, and by its fall, of about 3 feet, the 
globe of mercury became a little compreffed ; but in 
the former, only fome parts of the bulb fell off. 
Mr. Braun always found, that, casteris paribus, 
the more intenfe the natural cold was, the more eafy 
and more expeditioufly thefe experiments did fuc- 
ceed. 
In continuing thefe experiments he obferved, that 
double aquafortis was more effectual than fimple 
fpirit of nitre ; but that if both the aquafortis and 
Glauber’s fpirit of nitre, which he fometimes alfo 
ufed, were well prepared, the difference was not 
very confiderable. When his aquafortis was frozen, 
which often happened, he found the fame effedts 
from the frozen parts, when thawed, as from that 
part of it, which remained fluid in the middle of 
the bottle. Simple fpirit of nitre, though it feldom 
brought the mercury lower than 300 degrees, by the 
following method he even froze mercury with it. 
He 
