Weekly national intelligencer., 1851-11-08
COMMUNICATION.
Onthe Conversion Of Sea Waterinto Fresh Water
by Congelation.


Jy COngelafion.
Peceivng that you frequently assign portion Of the Ma
onal Inegencer diffusion Of scientific discoveries and
improvements in the arts venture to ask you publish the
accompanying memorial to the Secretary Of the Navy so-
citing his examination and adoption Of machine for convert
ing salt water into fresh by congelaton AS it is
that description Of device which renders nature
subservient to important object Of should be fur
nished enake to be understood which could not with
propey embody in memorial, must further request you
to admit the following into the columns Of the Integencer
Aware that the pages Of daily publication
suitable place for full detail and examination of phioso
Phcal subject than memorial to public officer shall
abrdge my explanations and remarks much deem the
novelty and importance of the subject win admit
1t is known to the public that have invented machine
for manufacturing ice by the rareaction Of atmospheric
afcaly condensed. As affords incontestsbe evidence
that produce ice chespy and abundsnty surprise has
been frequently expressed that it has been brought into
use and public journal, (Appletons Mechauics' Maga
zne in noticing account Of described in the London
Mechanics Magazine in operation Havans sks why
has not been introduced board Of vessels trading in the
ropcs and the adjacent Causes which need not be
explained but the nature of which will be readily surmsed
at least BY inventors have hitherto operated
teal in this country For the present Ideem sufficient
say that wished to mature its applicability the purpose
referred TO in the memorial before offered it the public.
The mechanical construction Of this machine having been
described in several Of the scientific journals of the United
States and Europe, must refer the reader them for de-
tailed account of it. Its important essential parts
consist Gas mentioned in the memoa of forcepumps
the object Of being condense atmospheric air.
out and render sensible large portion of its gaseous
heat and Of the other admit Of The expansion Of the same
air after is of s sensible heat They are connected
by common beam that while the air is expanding in
II is UNDERGOING condensation in the other and thus
large portion Of the mechanical power consumed in the latter
il furnished by the mechanical force exerted in the
former II is obvious that air in expanding energetic
absobe of heat, which it greediy takes from all adjacent
bodies is only necessary surround it the cylinder in
which the expansion takes place, with water dvest
its caorc Of udity, and thus effect the first object of the
invention. Limiting its action through the walls of pump
would however, be too slow process for practical purposes
and therefore i is prodigousy accelerated by various
ay apparatus contved the one hand to exngush the
heat and with it the mechanical force Of the caoric set free
condensation and the other furnish the cost of
The water TO be converted into ice the caorc Of elasticity
and mechanical force the expanding air. These with the
Of air reservoirs placed between the pumps and
novel Of producing an effective nsu
aon do not consider it necessary present describe
This machine, considered simply device for the arf
:al production of ice, is susceptible of great number Of
Useful applications. Viewed in relation the absence Of
,os of the materials employed, the simplicity and compare
lively small cost of construction, and the value of the results
has expementaly developed, ought mitch
tention FROM it is calculated modify and extend the
welfare Of mankind But in Of its applications would
emnenty useful than supplying the of fresh
WATER not only Of vessels navigating tho tropics and the
10 their neghborhood, but Of every engaged in voyage
Of more than few days duration.
Among tho great chemical aud purifying operations of
ue congeaon is recognised by Of science that
operates effecuay free water from all extraneous sub
Nor is the knowledge Of this purifying influence
limited of science Seamen. Of the nuturui
law, have been in the practice from time mmemoa of co
ectng ice found n and doubt formed FROM the water of
the ocean, and after dssovng, using it potable water
In many cold countries the effect Of freezing in congeang the
fresh and concentrating the brine Of has been taken
advantage Of to facilitate the production Of salt.
The natural operation by which ice and thence pure water
may be obtained from salt water by freezing be initiated by
Dr. Fsadsy has recently illustrated this fact by number
Of those beautiful experiments which have emneny ds,in
guished him philosopher in both hemspheres He has
shown tha. solutions Of SALTS akaes colong matters and
other substances which have been supposed have il
tain proportions indssolubIe affinity for water are expelled
from il by exposing them freezing mixtures Ice produced
under these circumstances found when dissolved to be
pure be obtained by the careful disa
and the important advantage that from its
greater affinity for air low than high temperatures it be-.
comes aerated fast as dissolved.
The explanation Of this interesting phenomenon simple
and the which is effected may be easily rendered
apparent the would appear that when reduc-
tion Of temperature brings within the sphere of cohe-
attraction this force itself between its particles
with much greater energy than between them and other
substances either in mixture solution, that it repes and
separates them When salt exposed sufficiently
low tempeau ure is be divided into parts. one
of which pure water and readily freezes the other re-
mains liquid, and becomes, by continuous reduction of tenn.
perature saturated solution Of salt. While the low tenn
peratue continues the bodies preserve their pecu
ar characters, the properties Of the compound
renewed except under the dissoving influence of caoric
Experiments incline 10 the opinion that saturated sou-
ton Of salt congeslable any temperature
though from slight and progressive dminution of the SOL
vent power Of wate under dimiouon of temperature il
commences precpang crystals Of hydrsted chloride Of
dum IA degrees Fahrenheit These crystals increase 10
quantity the temperature descends but the of the
liquid continues saturated and liquid for least several de-
grees below that assigned in works chemistry for s
geIaon There is in these facts, therefore, physical i'm
possibility for water obtained from ice contain any saline
mpuriy it is only necessary, when the ice is made from
salt water drain any brine with which il may be inter
mixed before dssovng it TO It's perfect purity
II proper mention that ice be obtained from salt
water quite readily from fresh water for it requires
de0vaoa Ioue, op;to