26 



THE SALTING OF FISH. 



salts used were pure sodium chloride in one case and sodium chloride 

 containing 1 per cent of calcium chloride in the other. It will be 

 noted that after seven days the chlorine content of the fish salted 

 with pure salt is nearly 2 per cent higher than that of the fish salted 

 with salt containing 1 per cent of calcium chloride. The chlorine 

 content of the fish salted with pure sodium chloride continues to in- 

 crease rapidly, whereas the chlorine content of the squeteague salted 



6 



10 



Fig 2 — Curves show retardation of penetration of salt due to 1 per ce^nt of magnesium 

 chloride impurity (section % to 1 cm. depth). Figures at left ijidicate per cent of 

 chlorine in dry fish ; at bottom, time in days. 



with salt containing calcium chloride increases very much more 

 slowly. 



Figures 2 and 3 show that the marked slowing up in the penetra- 

 tion of the salt into fish, due to the presence of magnesium chloride, 

 begins in about six days after salting. 



Figure 4 shows that the marked slowing up of the penetration of 

 the salt into fish in the case of salt adulterated with 10 per cent of 

 sodium sulphate occurs almost immediately. The amount of im- 

 purity used in this case was far in excess of any amount ever found 

 in any commercial salt. It is doubtful whether small amounts of 



