CHEMISTRY. 
mg experiment was goi-ng on, reducing it again to 50 0 
below o. 
We now put into the mixture a glafs tube containing 
fome mercury. In two minutes it was completely fixed. 
We broke the tube, and bent the cylindrical piece of 
mercury into an acute angle, by means of pincers : we 
attempted to ftraiten it again, but it became fluid during 
the operation. Several fubltances in proper veflels were 
now tried in the cold mixture. Sulphuric ether exhibited 
110 figns of congelation : rebtified fpirit of turpentine be¬ 
came thick and nearly confiftent at 50 0 below o; pure 
concentrated l’ulphuric acid was fixed : acetic acid like- 
wife was fixed : nitric acid became thick and ropy ; but 
on muriatic acid the cold had no effect. 
Encouraged by the luccefs of this experiment, we re- 
folved to attempt one of greater magnitude. Accordingly 
we weighed fifty-fix pounds avoirdupoife, of mercury, and 
prepared every thing neceftaiy forfixingthis quantity. The 
mercury was put into a ftrong bladder, and well fecured 
at the mouth, the temperature of the laboratory at the 
time being 33 0 . A mixture coniifting of muriat of lime 
a lbs. at 33 0 and the lame weight of 1'now at 32 0 , gave 
42 0 below o. The mercury, was put as gently as polfible 
into this mixture (to prevent a rupture of the bladder), 
by means of a cloth held at the four corners. When 
the cold mixture had robbed the mercury of fo much of 
its heat as to have its own temperature thereby railed 
from 42 0 below to 5 n above o, another mixture, the lame 
in every refpebt as the laft, was made, which gave, on 
trial with the thermometer, 43 0 below o. The mercury 
was now received into the cloth, and put gently into this 
new mixture, where it was left to be cooled Itill lower 
than before. 
In the mean time five pounds of muriat of lime, in a 
large pail made of tinned-iron japanned infide and out- 
fide, was placed in a cooling mixture in an earthen-ware 
pan. The mixture in the pan, which confided of four 
lbs. of muriat of lime and a like quantity of fnow, of the 
fame temperature as the former, in one hour reduced the 
five lbs. of muriat in the pail to 15 0 below o. The mix¬ 
ture was then emptied out of the earthen pan, and four 
large corks, at proper diftances, placed on its bottom, 
to lerve as refts for the japanned pail, which was now put 
into the pan. The corks anfwered the. purpole already 
mentioned, that of infulating the inner veffel, while the 
exterior one kept off the furrounding atmofphere, and 
preferved the air between the two at a low temperature. 
To the five pounds of muriat of lime, which had been 
cooled as already noticed, and which Itill remained in 
the metallic veffel, was now added fnow, uncompreffed 
and free from moifture, at the ufual temperature of 32. 0 , 
In lefs than three minutes the mixture gave a temperature 
of 6 z° below o ; a degree of cold never before fuppoled 
to have been produced in this country, being 94° below 
the freezing point of water. 
The mercury, which, by immerfio'n in the fecond 
cooling-mixture to which it was expofed, we found by 
this time reduced to 30 0 below o, was now, by the means 
employed before, cautioufly put into the laft-made mix¬ 
ture of the temperature of 6 z° below o. A hoop, with 
net-work fattened to its upper edge, and of fuch a breadth 
in the rim that the net-work, when loaded with the blad¬ 
der of mercury, could not reach its lower edge, was at 
the bottom of the mixture, to prevent the bladder from 
coming-in co/itabt with the veffel; by which means the 
mercury was fulpended in the middle of the mixture. As 
loon as the bladder was fafely depofited on the net-work, 
the veflels were carefully covered over with a cloth, to 
impede the paffage of heat from the furrounding atmof¬ 
phere into the materials. The condenfation of moifture 
from the atmofphere, by the agency of fo low a tempe¬ 
rature, was greater than could have been expebted : it 
floated like Iteam over the veflels, and, but for the inter- 
pofed covering, would have given the mixture more tem¬ 
perature than was definable. After one hour and forty 
VoL. IV. No. 305. 
3S5 
minutes we found, by means of a fearcher introduced 
for the purpofe, that the mercury was f’plid and fixed. 
The temperature of the mixture at this time was 46° be¬ 
low o; that is, 16 0 higher than when the mercury was 
firft put in. 
We now regretted that we had not flung the hoop and 
net-w'ork in the fame way as the fltell of a beam is fuf- 
pended, which would- have enabled us to lift it out of 
the mixture at once with the bladder and its contents ; 
but, having overlooked this provifion, we were obliged to 
turn out the whole contents of the pail into a large eva¬ 
porating capfule made of iron, which was not effected with¬ 
out the mercury ftriking againft its bottom, and at the 
fame time receiving a confiderable increafe of tempera¬ 
ture. The bladder was now cut. The eagernefs of our 
friends, of whom feveral were prefent, to be in poffefllon 
of pieces of the folid mercury, which had frabtured by 
the fall it had received, was paft defcription. Forgetting, 
and perhaps not being aware of the confequence, fome 
rufhed their hands into the frigorific mixture, while lonie 
feized on pieces which others, having ielected with their 
eyes as their prize, alfo laid hold of at the fame moment, 
and confequently each grafped them harder than otherwise 
they would have done. The acute pain that inftantly 
followed, quickly recalled their recollection, and, bur. 
for the lufferingsof the individuals, thefcene would have 
excited no fmall degree of mirth : fome clapt their hands- 
into their mouths, others fiiook them, blew on them, or 
rubbed them againft their clothes; and all were more or 
lefs alarmed at the dead appearance of the parts that had 
been fo fuddenly robbed of heat by the frozen metal. Ic 
was a confiderable time before fenfation and the natural 
colour was reftored to the parts, which however returned 
without any other means being employed than fuch as 
have been mentioned. It is eafy to conceive that the in¬ 
jury was little more than Ikin deep, like what takes place 
from touching a hot metal, without allowing it to remain 
long enough in contact with the Ikin to produce a wound; 
but what is very lingular, almoft every individual com¬ 
pared the fudden pain he experienced to that produced 
by a burn or fcald! One gentleman, who called acciden¬ 
tally while we W'ere preparing for our experiment, but 
who had no acquaintance with the fubjebt, not being' 
able to conceive how the effebt propofed could be pro¬ 
duced by the mixture, was defired to take a little fnow 
in one hand and muriat of lime in the other : “ they were 
neither of them colder than he expedited to find them 
then to put the fnow into the hand that held the muri't. 
The ingredients had hardly come in contact when' he 
threw them from him, exclaiming, “ Cold !—'Tis a red- 
hot coal !” 
The larger pieces were kept for fome minutes before 
fufion took place, while others were twilled and bent into 
various forms, to the no fmall gratification and furprile 
of thofe who had never witneffea or expedited to fee fuch 
an eft'ebt produced on fo fufible a metal. 
Though mercury in the Hate in which we had it, ex¬ 
hibited a confiderable degree of dubtility and malleabi¬ 
lity, w'e cannot thence infer the degree in which they 
would be found to belong to it, could it be reduced to 
a temperature much more confiderably under its freezing 
point, which leems to be at about 39 0 or 40 0 below o. 
At the time that we bent and twilled it, it may be con- 
lidered as having been in a proportionate temperature to 
iron near its point of fufion, when, as is well known, it 
will hardly bear the fmallelt blow of a hammer. 
The apparatus employed in thefe experiments is re- 
prelented in the Chemiltry Plate IX. Fig. 5, reprefents 
that employed in the firft experiments; and only viewing 
the figure will convey to any one a complete idea of the 
arrangement, as it exhibits the retort containing the mer¬ 
cury, furrounded by' the cooling-mixture in the half-pint 
cup, which is infulated by means of the corks, and pre¬ 
vented from coming in contact with the ftone-ware jar 
the Ipace between the latter being occupied only with 
5 F 'cold 
