A HISTORY OF SALT-MAKING IN ESSEX. 203 



a brass skimmer. Soon after the water has boiled, salt-crystals 

 begin to form on the surface, in a manner which is most interest- 

 ing to watch. These crystals (PI. xxxii) are extremely curious 

 objects — thin, white, shell-like, quadrangular at base, rising in 

 the shape of a pyramid with a truncated cone. 29 In size, they 

 vary greatly — some being as much as two inches square : others, 

 equally perfect, no more than one-eighth of an inch. The form 

 is invariable, but the size seems to be determined at the com- 

 mencement of crystallization ; and, after a crystal has started to 

 form, it does not grow. The gentler and shorter the boiling, the 

 finer and more perfect the crystals : violent boiling breaks them 

 into fragments. Such crystals as these are often called " hopper- 

 crystals " (in French, tvemis). Maxwell Lyte says™ that they 

 tend to form only in still brine. It is said, 81 too, that the addition 

 of a small quantity of alum to the brine tends to increase 

 their size, but this is not done, I believe, at Maldon. 

 Finally, those crystals which have formed on the surface 

 are skimmed off and set aside for use as the finest 

 table-salt ; those low r er down are next taken out and used as 

 pickling-salt ; while the residue then left in the pan, being less 

 pure, serves for agricultural purposes. This operation 

 is repeated daily, two pans being boiled, the daily yield of salt 

 being about half a ton, or about eighty tons annually. 



This output is, of course, insignificant in quantity when 

 compared with that of the Cheshire and Worcestershire rock- 

 salt industry, amounting to hundreds of thousands of tons 

 annually ; but, in respect of purity and attractive appearance, 

 Maldon Crystal Salt is far superior to any other produced in 

 Britain, and this enables it to hold its own on the market- 

 Practically, indeed, it reaches the standard of absolute chemical 

 purity, consisting of common salt (chloride of sodium) with an 

 admixture of no more than 0*383 per cent, of other matter, as 

 the following analysis by Dr. A. H. Hassall shows : — 

 Maldon Crystal Salt Company's Pure Table Salt, 



( 100 parts by weight) 



Chloride of Sodium 99-617 



Chloride of Magnesium o - i98 



Sulphate of Magnesium 0-067 



Sulphate of Lime o- 1 1 8 



Total ioo-ooo 



29 A salt-crystal forms the trade-mark of the company. 



30 Spoil's Cyclopcedia, ii, p. 1710 (1882). 



31 Thorpe's Die. of Applied Chemistry, iii, p. 436. 



