WATER 17 



chlorine, sulphuric, carbonic, phosphoric, nitric and 

 nitrous acids. 



The significance of these, and the reason why they are 

 looked for, has been previously dealt with. Their amount 

 can be determined by a quantitative analysis, which like 

 the bacteriological examination of water requires an 

 expert. On the other hand, a qualitative examination is 

 not only simple and easily performed with a few reagents, 

 but for veterinary purposes conveys nearly if not all the 

 information likely to be required. 



Reaction. — Take the reaction of the water with test- 

 papers, good water is usually neutral ; if it is acid and 

 the acidity disappears on boiling it is due to carbonic acid. 

 If it is alkaline and the alkalinity disappears on boiling it 

 is due to ammonia ; this reaction, however, is extremely 

 rare. If the water remains alkaline after boiling, the 

 alkalinity is probably due to soda carbonate. 



Lime is present in the form of carbonate, sulphate, 

 chloride or nitrate. To ascertain its presence, a solution 

 of ammonium oxalate is employed, which produces a 

 precipitate of lime oxalate. 



On the density of the precipitate obtained a rough guess 

 of the amount of lime present may be made ; it will vary 

 from a faint haze to a well-marked turbidity. Six grains 

 of lime to the gallon gives a marked turbidity, while 

 sixteen grains produces a considerable precipitate. Six 

 grains of lime per gallon may be found in the best waters, 

 some are even softer than this. 



The question of the degree and nature of the hardness in 

 water is one frequently arising, owing to the well-founded 

 prejudice against the use of hard water for horses. By a 

 very simple examination it is possible to determine roughly 

 to what salts the hardness is due, and whether any 

 softening of the water is possible. 



If the specimen of water under examination be boiled, 

 the lime to which the temporary hardness of water is due 

 is thrown down. Any lime now left is probably calcium 

 sulphate, which is largely responsible for permanent hard- 



2 



Digitized by Microsoft® 



