66 



remains throughout, and whatever the variable quantity of chalk 

 present after softening may happen to be, all excepting about 1.3 

 parts is precipitated. 



The nitrogenous compounds in the water — free ammonia,, 

 salts of ammonia, organic or albumenoid ammonia, and 

 nitrates — are present in sufficient small quantities to permit of 

 the water being classified as one of high organic purity. 



We consume a certain amount of iron with our water, but 

 only to the extent of 7 or 8 parts in a hundred million, which is 

 so low a value as to justify its being entered in reports as " a 

 trace" and so dismissed. Small as this quantity is, however,, 

 slight but definite variations are noticeable. 



Chlorine in the form of sodium chloride is present in much 

 larger quantity, and keeps very constant. Of eight, determina- 

 tions, six give results of 1.8 parts of chlorine in 100,000 parts of 

 water, and two give 1.85 parts per 100,000. A constant impurity 

 such as this is valuable as it immediately reflects any radical 

 change in the water at its source. 



Compared w T ith the water of other districts, the chlorine con- 

 tent of the local waters has the virtue of being strictly moderate. 

 Some figures are : — 



West Hants Water Company 1.4 parts CI. 



Poole Water Supply 2.4 

 The River Stour 1.6 

 Peaty waters from Hern (average) 1.6 



Sea salt is carried inland by the wind, and probably finds 

 its way into every one of the local waters, consequently what 

 differences exist are possibly due to different proportions of the 

 respective waters being collected on lands near the sea. This 

 seems to be demonstrated by a comparison of the Avon water — ■ 

 which contains only 1.3 parts — with samples from the Bourne, 

 which contains twice this amount just below Coy Pond, and still 

 more just before the Square, which of course is nearer the sea. 



A well at Wick contrasts with all the foregoing in containing- 

 13.4 parts of chlorine — a quantity sufficient to condemn it in- 

 stantly if one cared to dogmatise on the question of salt being 

 an index to pollution. An amount of chloride much above the 

 average for a particular district certainly suggests possible pollu- 

 tion, but all the conditions should be taken into account, and it 

 seems from the situation of this well that it must receive water 

 from higher lands which are subject to the full blast of the salty 

 Southbourne winds. 



This well, which is passed by the road-side as one walks 

 from Tuckton Bridge to Christchurch Head, and is probably 

 familiar to many people, is not easy to pronounce upon and is 

 of interest on that account. It gives a clear yellow water. The 

 hardness is quite of an average value, namely 17-|, but the water 

 is rich in dissolved organic matter, and nitrates and organic 



