64 The N.Z. Journal of Science and Technology. [Jan. 
CORRESPONDENCE. 
The Specific Gravity of Ice.—Moisture in Frozen Meat. 
Sir, —In the last issue of The N.Z. Journal of Science and Technology 
(Nov., 1918) Mr. G. L. D. James, in his interesting article “ The Efficiency 
of the Frozen-meat Industry,” makes the statement (p. 344) that freezing 
increases the volume of water one-seventh. Possibly Mr. James intended 
to write “ one-eleventh ” instead of “ one-seventh.” On consulting 
numerous authorities (1906 and earlier) I find an extraordinary diversity 
of statements, according to which the expansion of water in freezing may 
be anything from rather less than one-seventh to less than one-twentieth 
of its volume. The highest specific gravity found is in Molesworth’s Pocket 
Book of Engineering Formulae , where, on the authority of de Mairan, 
it is stated that the specific gravity of (ordinary) ice is 0*926 ; that 
of ice made from water free from air, &c., is 0*954. Can it be that so 
important a physical constant as the expansion of water during freezing 
has not yet been accurately and authoritatively determined ? Several 
well-known text-books are apparently not correct on this point. As a 
rule, they mention the “ exact experiments ” of Bunsen,* who determined 
the specific gravity of ice at 0° C. to be 0*91674, that of water at 0° C. 
being the unit, but fail to give details of the experiments, or to hint at the 
variation caused by included gases. 
An obvious slip of the pen makes Mr. James say, “About 70 per cent, 
of the moisture in meat is water,” his intention evidently being to say 
that meat contains about 70 per cent, of water. From a consumer’s 
point of view the loss of a few per cent, of this moisture does not appear 
to be any great misfortune. In fact, the moie moisture that can be 
removed the less the cost of carriage ought to be, and, I fancy, the better 
the meat will keep after thawing. Apparently the only real loss of food 
in the frozen-meat trade under ordinary conditions is the loss through 
“ railing and droving,” which takes place before the stock enter the 
freezing-works. (I wonder what becomes of the animals, equivalent to 
173,000 carcases of 601b. each, “ lost ” in this way.) As for the possibly 
excessive empirical deductions made by middlemen for loss of weight 
owing to moisture-evaporation, that is another matter, which can be very 
easily checked, as Mr. James suggests, by the use of weighing-machines. 
P. G. Morgan. 
Wellington, 31st December, 1918. 
* H. E. Roscoe and C. Schorlemmer, A Treatise on Chemistry, vol. 1, p. 298, 
1905. Reference given to Phil. Mag., vol. 41, p. 165, 1871. [An attempt to follow up 
this reference brings out the astonishing fact that the only set of the Philosophical 
Magazine in Wellington is very incomplete, and that the volume for 1871 is not 
available. Such is the condition of scientific libraries in New Zealand !— Ed.] 
By Authority: Marcus F. Marks, Government Printer, Wellington.—1919. 
[1,800/12/18—18055 
