COL 
to produce artificial cold, are generally 
made of the neutral salts dissolved in wa- 
ter,; of diluted acids and some of the neu- 
tral salts; and of snow or pounded ice with 
some of tliese salts. A great number of ex- 
periments were made upon this subject by 
Mr. Walker; also by Professor Lowitz of 
Petersburgh ; by Fourcroy and Vauquelin ; 
and by Guyton. The following table exhi- 
bits tlie results of some of these experi- 
ments. 
Table of freezing mixtures. 
Mixtures. Thermom. sinks. 
Parts. 
1. Muriate of am- 1 
H from 50" to 10". 
Nitre 51 
Water 16 ' 
2. Muriate of am- 
monia 5 / 
Nitre 5 > from 50® to 3". 
Sulphatcofsoda 8V 
AVater 16 ^ 
3. Sulphate ofsoda 5 
Diluted sulphu- 
ric acid 4 
4. Snow 1 
Common salt.... 1 
3. Snowor pound- 
ed ice 2 
Common salt ... 1 
6. Potash 4 
Snow 3 
7. Muriate of lime 3 
Snow 2 
8. Muriate of lime 2 
Snow 1 
9. Muriate of lime 3 
Snow 1 
10. Diluted sulphu- 
ric acid 10 
Snow 8 
from 50° to 0®, 
from 52° to 0®. 
from 0" to — 5". 
from 32° to — 51°. 
^from 32" to — 50". 
^ from 0" to — 66°. 
^ from— 40" to —73". 
> from — 68° to — 91". 
When any of these substances are to be 
employed as freezing mixtures, the salts 
should be used fresh crystallized, and re- 
duced to fine powder : and it will perhaps 
be found most convenient to observe the 
proportions which are set down in the ta- 
ble. Suppose it is wanted to produce a de- 
gree of artificial cold equal to — 50°, which is 
the temperature produced from 32° by the 
seventh freezing mixture. The. substances 
employed, namely, the muriate of lime and 
tlie snow, must be previously cooled down 
to the temperature of 32°, or any degree 
below it. This mhy be done by placing 
them separately in tlie third freezing mix- 
ture, the sulphate of soda, and diluted sul- 
phuric acid, which reduces the temperature 
VOL. II. 
COL 
from 50° to 3° ; or in the fourth freezing 
mixture of snow and common salt, which 
reduces the temperature from 32° to 0°. 
The materials thus cooled down, are then 
to be mixed together as quickly as possible, 
when, if tiie experiment, succeed, the tem- 
perature will fall from 32° to — 50°, as in 
the seventh freezing mixture. The vessels 
which are employed for these proces.ses 
should be very thin, and made of the best 
conductors of heat. Vessels of tin plate 
answer the puipose, and wdien acids are to 
be used, they may be lined with wax, 
which will secure them sufficiently agahist 
their action. They should be of no larger 
dimensions than just to contain the mate- 
rials. 
GOLDEN lA, in botany, so called in ho- 
nour of C. Golden, a curious botanist of 
North America ; a genus of the Tetran- 
dria Tetragynia class and order. Natural 
order ; Asperlfoliae. Borraginea;, Jussieu. 
Essential character : calyx four-leaved ; co- 
rolla funnel formed ; styles four ; seeds two, 
two-celled. There is but a single species, 
viz. G. procumbens, an annual plant, whose 
branches trail on the ground, they extend 
nearly a foot from the root, and divide into 
many smaller branches. It is a native of 
the East Indies, but has been cultivated 
here for half a century. 
GOLEOPTERA, in natural history, an 
order of insects, w'hich includes all those 
whose v.dngs are guarded by a pair of 
strong, horny, exterior cases or coverings, 
under which the wings are folded up when 
at rest. In common language these insects 
are called beetles, though, in reality, that 
term is now restricted to the Scarabmus 
genus. The wing-sheaths, or horny cover- 
ings,- are sometimes called coleoptera, but 
more generally elytra. Tliis is a very ex- 
tensive order, divided into four classes. 
A. antennae clavate, thicker towards the 
tip : in this class there are three subdivi- 
sions ; viz. 
a. Glub lamellate ; three genera. 
Lucanus Scarabaeus Synodendron. 
b. Glub perfoliate ; seven genera. 
Byrrhus Dennestes Hydrophilus 
Melyris Silpha Tetratoma 
Tritoma. 
c. Glub solid or inflated ; seven genera, 
Anthreuus Bostrichus Goccinella 
Gurculio Hister Nitiduia 
Paiisus, 
R 
