BY THE HON. W. F. TAYLOR, M.D., ETC. 35. 



Cliemical constituents. 



The chlorine in chlorides should be under g. 1*0000 per gallon. 



Total solids in solution ,, ,, 5-0000 ,, 



volatile „ „ 1-0000 



Ammonia, free or saline ,, ,, 0-0014 ,, 



,, albuminoid ,, ,, 0-0035 ,, 



Nitric acid (NOg) in nitrates ,, ,, 0-0226 ,, 



Nitrous acid (NOj) ,, ,, ,, Nil. 



Nitrogen in nitrates ... ... under O'OIOO ,, 



Total combined nitrogen, including that in 



the free ammonia ; should be under ... 0-0112 ,, 



Total nitrogen, including that in the albu- 

 minoid ammonia, should be under ... 0-0163 ,, 



Hardness, total, should be under... ... 6-0 ,, 



,, fixed, ,, 2-0 ,, 



An amount of chlorides much in excess of the quantity per 

 gallon stated above, viz., one grain, would render the water 

 suspicious ; and if in addition the albuminoid ammonia exceeded 

 to any great extent 0-0035 of a grain per gallon, sewage con- 

 tamination would be suspected, and the locality carefully 

 examined for a possibility of such. "Water possessing a perma- 

 nent hardness of over 10 degrees of Clark's scale, is injurious, 

 and may in many cases gives rise to dyspepsia, diarrhoea or con- 

 stipation. The permanent hardness depends on calcium sulphate 

 and chloride, and magnesium salts ; the temporary hardness is 

 due to calcium carbonate held in solution by an excess of car- 

 bonic acid gas in the wat(;r. Boiling, by driving off the carbonic 

 acid, precipitates the calcium carbonate ; so also does lime water 

 when added to the water, by combining with the COo. Time 

 will not permit me to enter into any detail respecting the means 

 adopted to demonstrate with accuracy the degree of hardness, 

 temporary and permanent, of water. The test is called after 

 the discoverer — Clark's test — and is based on the well-known 

 curdling properties which hard water possesses over soap. An 

 estimate sufficient for domestic purposes may easily be arrived 

 at by noting the difficulty experienced in producing a lather 

 with soap. Soft water rapidly produces a lather without any 

 such feeling of resistance as is imparted to the hands when 



N.B. — Solids on incineration should scarcely blacken. 



