WATER 1 1 



waters can be completely softened by passing them through 

 permutit. Dr. Thresh gives evidence to show that no harm results 

 to people from habitually drinking water containing the unusual 

 amount of sodium salts that permutit treated waters and naturally 

 softened waters contain. He points out that the permutit system 

 of water softening is the only one that is applicable to any kind of 

 water. 



THE ACTION OF WATER ON METALS. 



Plumbo-Solvency of Water. Certain classes of water possess 

 a solvent or an eroding action on lead. Animals or people drinking 

 water that has been conveyed any distance in lead pipes, or has been 

 stored in lead cisterns or has stagnated for any period in lead pipes 

 may, if the water is lead-solvent, take into their system minute 

 quantities of lead. Lead, however, is cumulative, so that if water 

 containing the merest trace of lead be habitually drunk there will 

 come a time when toxic effects will be produced and symptoms 

 of lead poisoning apparent. Serious cases of lead poisoning have 

 occurred in both animals and man, and the cause and nature of the 

 illness has not always been suspected. 



Water derived from peat moorlands is often acid and is there- 

 fore lead-solvent. During a dry period water coming from the 

 moors is chiefly of spring origin and is not acid. The first water 

 washed from the moors after a dry period is very acid, and it 

 contains the water that has been lying stagnant in pools and 

 marshes. This is most dangerous. The acidity lessens after the 

 ground has been well washed by heavy rains. 



Waters well oxygenated, and those containing much free CO 2 , 

 are lead-solvent, and so also are waters with much organic matter 

 or nitrates in solution, especially if the water is soft. Rain water 

 dissolves lead. 



Hard water attacks new and untarnished lead, but there is soon 

 formed a coating of basic lead carbonate which prevents any 

 further action. 



Acid water containing free CO 2 is lead-solvent, while neutral 

 water containing much dissolved oxygen has an erosive action. 



It is important to remember that the lead-solvent power of a 

 water is not constant, a moorland water when tested at one season 

 may be free from any objectionable action while a few months 

 later it may be quite dangerous. 



Whenever it is known that a water may have a lead-solvent 

 action the use of lead service pipes or lead containers should be 

 avoided. The water may be treated with lime or chalk to neut- 



