78 DR. R. ANGUS SMITH ON THE EXAMINATION 



NOj is equals we require only to multiply by 2000 to ob- 

 tain the amount of solution of chameleon. But we may 

 do it still more easily by simply multiplying the amount 

 of NO J obtained by 842 as a whole number. This gives 

 the amount of chameleon solution to which it is equal. 



" The estimation of both is interesting ; but it is much 

 more important to obtain the total chameleon used^ as the 

 presence of NOj must be considered a great objection to 

 water, partly on its own account, and partly because of its 

 origin. 



^^ It is to be observed that water containing much animal 

 matter becomes extremely acid. It is a common thing to 

 find water extremely clear, with no apparent organic 

 matter, even on standing, also extremely acid, and retain- 

 ing nitrates. I have found it so filled that it appeared to 

 flow less readily than pure water, and had a most nauseous 

 taste. It was close to a churchyard, and was considered 

 excellent water. This perversion of taste is difficult to 

 understand, but it must be combated; it is not natural, 

 and causes illness and death. This acid water is an excel- 

 lent solvent of metals ; and if lead is present, the solution 

 becomes rapidly so strong as to taste of the metal. This 

 acidity, in conjunction with nitrates, does not, so far as I 

 know, exist when the organic matter is very old, probably 

 because the organic acid is oxidized. Some of it, probably 

 all, is caused by the formation of organic acids. Similar 

 organic and entirely colourless solutions, acid, but free 

 from nitric acid, may be found by allowing peaty water to 

 stand without evaporation, but in contact with air, for 

 some years. 



" In the nitrous waters no organic matter will be apparent 

 on burning unless there is more than the acid can oxidize. 

 A very white ash is, therefore, a suspicious circumstance ; 

 and unless the matter is extremely free of organic matter, 

 this white ash is a certain indication of nitric acid. If 



