162 The N.Z. Journal of Science and Technology. [Aug. 
can be prevented by close attention to the maintenance of cleanliness and 
prompt handling of the hides as soon after slaughter as possible. 
Water-supply. (43, 46, 47, 52, 55.) 
It is not proposed to consider here the question of the quality and 
nature of the water-supply for boiler purposes, a consideration of which 
is outside the scope of this article. It should be borne in mind, however, 
that the use of so-called “ boiler compounds ” employed in remedying or 
preventing scale-formation has to be considered in the light of the sub¬ 
sequent use of the steam in the manufacture of food substances, and the 
danger of imparting undesirable odours and flavours from such a source 
should not be overlooked ; while in the case of certain compounds which 
are poisonous, the law s 
in food-manufacture. 
A number of general considerations should be taken into account in 
regard to the water to be supplied to certain departments and operations 
connected with the frozen-meat industry. For obvious reasons, water 
used in the manufacture of edible fats should be as free as ‘possible from 
organic matter. This is important in view of the fact that the raw fats 
are held in cold water for periods up to fifteen hours so that they may be 
hardened. In such cases it is not the actual organic matter which pro¬ 
duces ill effects, but the fact that waters rich in organic matter form a 
suitable nutrient for putrefactive organisms. The water should also be 
as free as possible from suspended solids ; and, for reasons of subsequent 
economy in operation when the chilling of the water is required for edible 
fats, a low original temperature as it reaches the department is desirable. 
The hardness of the water has apparently no effect upon the success or 
otherwise of its use for edible-fat manufacture. 
For meat-extract manufacture the water should be free from suspended 
matter and low in total solids. Sulphate of lime and magnesium salts in 
excess have been found in meat-extracts manufactured from meat-tissue 
which has been extracted with water containing a high amount of total 
solid matter. 
For meat-preserving purposes the water should be as free as possible 
from organic matter, iron compounds, and suspended solids. For fell- 
mongering purposes water with a low degree of hardness is desirable ; it 
should be free from undue salinity. 
In the preparation of the pelts for curing, the water should be as free 
as possible from organic matter. Water with an excessive temporary 
hardness should be avoided, for if such is used for washing the limed skins 
“ lime-blast ” is liable to be produced in consequence of the deposition 
of the carbonates of lime and magnesia in the pelt-fibres. The temporary 
hardness in water used for this purpose can be eliminated by adding 
freshly made lime-water. Waters containing an excess of carbonate of 
soda also tend to cause “ lime-blast,” and chlorides if present in excess 
tend to prevent the swelling of the hide substance. Iron if present beyond 
a trace will produce a decided darkening in colour of the pelt. This 
darkening may not be very noticeable in the pickled pelt, but when the skin 
is subsequently tanned marked darkening will be manifest. 
Sewage. (31, 44, 45, 50, 51, 53, 55.) 
Probably, in the case of most of the freezing-works, direct discharge 
into the nearest body of water is the commonest method of sewage-disposal, 
pecifically prohibits their use where steam is employed 
