No. 112.) 269 



quescent chlorides, have been found to be those which in practice 

 answer best. This is rather remarkable." 



In the course of my inquiries, I have frequently found the 

 most violent and groundless prejudices against particular varie- 

 ties of common salt, existing in the minds of intelligent and prac- 

 tical men. The distinguished Dr. Samuel Mitchell, of New- York, 

 in 1803, wrote a letter to Dr. Caldwell, on the injurious proper- 

 ties of Liverpool salt. This letter was published in the Medical 

 Repository, vol. 7. He says, '' In the course of trade between 

 America and Great Britain, it has become the misfortune of the 

 United States, to be visited with frequent cargoes of salt from 

 Liverpool. This article is prepared on the western coast of 

 England, where coal for fuel can be bought at a low price, by 

 boiling ocean water or briny spring water, saturated with the 

 rock-salt of Northwich, in large and shallow pans of iron. The 

 native mineral salt of Cheshire, is carried coastwise to Lancashire 

 for that purpose. The salt which remains after the water has 

 been evaporated by force of fire, is called 'pan salt^ and is a med- 

 ley of saline substances. It is very different in its qualities from 

 the pure muriate of soda ; for wiiereas that is the most agreeable 

 of the antiseptics, and ranks among the strongest ; this mixture of 

 impurity and trash is remarkable for possessing the reverse of those 

 valuable properties. Indeed, this artificial salt is exceedingly 

 unlike the salt formed by the evaporation and crystallization, 

 which sea-water naturally undergoes in the warmer latitudes. 

 There is a remarkable difference between that vile and heteroge- 

 nous mass sold in the American ports, under the name oi blcwn 

 salt or Liverpool salt, and the efficacious apd excellent article 

 brought Irora the Canaries, Cape de Verde and Bahama Islands. 



• 



"The frequent and intimate connexion between tlie American 

 ports of New-York, Philadelphia, Baltimore, &c.,and the town of 

 Liverpool, has rendered it very convenient, in the course of com- 

 merce and navigation, to throw in salt at the latter place i\>t bal- 

 last, or part of a cargo, to the American market. The cheapness 

 of fuel from the neighljoring coal mines in Lancashire, enables 

 the salt boilers to sell their manufarture cheap ; and lience it hap- 

 pens that sliips about to come to America, either empty, or with 



