b o o k revivified mercury, twice diftilled with fixed alkali by Mr.
XI. -
_ i Winterberger, a preparation which has been faid to refill
a greater degree of cold than the others j but we found that
it froze in 2 i minutes exadtly at 32 degrees of Reaumur’s
mercurial thermometer, in the firll glafs of cold mixture,
and differed in nothing from all the other forts excepting the
following.
Ninth experiment.—Mercury purified with antimony froze
in two different experiments at 30 degrees with a fpirit thermometer,
and in one with a mercurial thermometer at 32 degrees,
fo that there adtually appears a difpolition in this preparation to
freeze with a lefs degree of cold than the others; but it mull be
remarked, that it has a blackifh dull colour and fluggifh motion.
Tenth Experiment.— Mr. Coxe being curious to try the malleability
of the mercury diftilled with alkali, which has a very
bright and fluid appearance, I froze fome of it in a tube, at the
fame time cooling the hammer in the refrigerant mixture, fo as
to acquire the fame temperature as the frozen''mercury, defending
the iron from the adtion of the nitrous acid by means of a
glafs cylinder. This mercury bore feveral ftrokes of the cold
hammer, flattening like a leaden bullet.
. Eleventh experiment.— I laftly froze fix drachms of common
mercury, containing twelve times as much tin foil as in experiment
the fixth; but even this quantity of alloy, which rendered it
almoft an amalgama, did not difpofe it to freeze with lefs than
32 degrees of Reaumur.
February
February 16, O. S.— A cold of 24 degrees offering moil unex- c H^A p.
peitedly this morning, fo very late in the feafon, and another expe- i ---
riment having been fuggefted to me by an ingenious friend, Mr.
Romme, to put the point of congelation of impure mercury flill
in a clearer light, I tried it about mid-day, when the cold was
diminifhed 4 degrees in the fhade.
Mr. Romme remarked, that mercury takes up much more
bifmuth than tin without lofing its fluidity or colour, and as
bifmuth is a metal much oftener ufed to adulterate it, and
very difficult to be feparated from it, he thought therefore a .
mixture of them was a very proper fubjeft of experiment to decide
the queftion. I accordingly prepared an amalgama fo thick,
that it filvered glafs like a mirror by merely running over it, and
adhering fo fail as not to be removed without fcraping. But
flill the freezing point of this very impure mercury was the
fame as the others j viz. 32 degrees of Reaumur, by the mercurial
thermometer. The fpirit thermometer being employed-to try the
cold of the frigorific mixture, to myfurprize fell no lower than
the other thermometer inferted in the mercury contained as
ufual in a tube.
Thus ended my experiments this feafon; and I think I may
venture to draw the following inference from them:
That the point of congelation of mercury is at 32 degrees below
O on Reaumur.
That there appears no difference in the point of congelation of
purified and common mercury, except one preparation with antimony