THE SALTING OF FISH. 



23 



water near this temperature. The temperature did not vary more 

 than 2.7° from the average. The fish were sampled at about 48- 

 iiour intervals. In sampling, a transverse section, about 3 inches in 

 width, was cut from a fish. A layer, 0.5 cm. in depth, was cut from 

 the outside of the fish, which had been exposed to the brine. A 

 second layer, underlying first layer 0.5 cm. thick, was then cut for 

 a second sample. These samples were then dried at 100° C. and 

 ground up. The percentage of chlorine was then determined by 

 first carefully ashing the fish in silica dishes and afterwards titrating 

 the chlorides with tenth-normal silver nitrate, using potassium chro- 

 mate as indicator. The inner section (one-half to 1 cm. in depth) 

 was found to be of the most uniform composition. Analysis of dif- 

 ferent fish from a single lot showed that this layer did not vary 

 more than 1 per cent in chlorine. 



DISCUSSION. 



The results of the work which has been completed are given in 

 Tables 1 to 4 and are shown graphically in the curves, figures 1 to 4. 

 The work shown in Tables 2, 3, and 4 was all done at the same time 

 with fish of the same relative freshness, and the temperatures of the 

 brines were kept uniform. The work reported in Table 1 was done 

 at a different time with a different lot of fish of somewhat larger size 

 and heaviei^" scale. As a result, the data in Table 1 are not comparable 

 with those given in the other tables. 



The results of the analyses of the dry fish samples are shown in 

 Tables 1, 2, 3, and 4. The figures in all cases refer to the per cent of 

 chlorine in dry fish. In Table 1 the analyses of sections of fish salted 

 with a salt so prepared as to contain 1 per cent of calcium chloride 

 and analyses of sections of similar squeteague salted with pure salt at 

 the same time under identical conditions are presented. 



Table 1. — Retardation of Penetration of Salt into Fish Due to 1 Per Cent 

 OF Calcium Chloride Impurity, EJxpressed in Terms of Per Cent of 

 Chlorine in Dry Sample, at 62.5° F. 



a to i cm. 



6 J to 1 cm. 



It is to be noted that the sections, both inne^ and outer, of the fish 

 salted with pure salt ran higher in chlorine content than those salted 

 with salt containing 1 per cent of calcium chloride. 



In Table 2 data are presented which were obtained from the salt- 

 ing of another lot of squeteague with pure salt and from a similar 

 lot salted with salt so prepared that it contained 1 per cent of mag- 

 nesium chloride impurity. 



