350 CHRONOLOGICAL HISTORY OF THE HERRING FISHERY. 



4. Encouragement should be given to the fish-curer to 

 cure the herrings in oaken barrels ; the Dutch do not 

 generally cure in any other. We are of opinion that oak 

 is not only, from its strength and retentive quality, the 

 best suited for this purpose, but that there is also a pre- 

 servative quality in this wood, and that it moreover im- 

 parts a pleasant flavour to the herring. 



5. Every means should be adopted to improve the 

 manufacture of salt. The salt manufactured in this 

 country is generally of very inferior quality ; and the 

 same common process of boiling or evaporation has been 

 followed for centuries. Simple evaporation does not leave 

 the pure preservative salt or muriate of soda. 



Our common salt is composed of — 



Muriate of Soda, or Pure Salt. 

 Sulphate of Magnesia, or Epsom Salt. 

 Muriate of Magnesia. 

 Muriate of Lime. 

 Sulphate of Lime. 



The sulphates and muriates of magnesia and lime are 

 injurious to the process of curing. 



The muriate of magnesia is partly detached from the 

 common salt in a liquid state, and forms a great portion 

 of the liquid collected at salt works called bittern, from 

 which magnesia is made ; but it is evident that a great 

 part must remain with the crystals under the common 

 process of manufacture. The sulphate of magnesia, or 

 Epsom salt, is also contained in the bittern, but part re- 

 mains with the crystals. These, as well as the muriate 

 and sulphate of lime, besides giving a disagreeable taste 

 to the common salt of this country, interfere with, or to 

 a certain extent prevent, the antiseptic qualities of the 

 pure salt. 



