No. 4.] STABLE MANAGEMENT. 175 



as a rule, organically pure, but contains a large amount of 

 mineral substance, as lime and magnesium, rendering it ex- 

 ceedingly hard. Surface waters, especially from cultivated 

 lands, and marsh waters, are usually very impure, from the 

 amount of organic matter they contain. 



The impurities found in wells are derived from surface 

 washings and soakage through soil impregnated with or- 

 ganic matter; from pipes or cesspools containing animal 

 excreta, and the leakage finding its way into the soil to be 

 carried into the nearest well. Shallow wells near buildings 

 or stables, or close to manure pits, are simply receptacles 

 for tilth. 



Dissolved Solids. 



We have now to consider the chemical examination of 

 the water for dissolved solids. These consist of lime, mag- 

 nesia, soda, potash, ammonia, iron, alumina, combined with 

 chlorine, sulphuric, carbonic, phosphoric, nitric and nitrous 

 acids. Let us clearly understand, before we proceed further, 

 what the object is of determining the presence of these sub- 

 stances in water. We may rightly argue that the addition 

 of them to drinking water would, in the small quantities in 

 which they are found, be utterly unproductive of harm. 

 Perfectly true. We might add all these substances in the 

 proportion in which they are found in bad water, viz., only 

 fractional parts of grains, and yet not in the least impair 

 the purity of drinking water. Why, then, does the chemist 

 lay such stress upon their presence, and what is the object 

 of the careful and often tedious process for isolating each 

 substance and estimating its quantity? The object of this is 

 that the elements, as we obtain them, are indications of the 

 compounds in which they exist, and are undoubted proofs 

 of the entrance into the water of substances containing these 

 elements. 



If we look back at the whole range of organic and inor- 

 ganic substances, we shall find that there are but few of them 

 which do not contain the elements and acids we have named. 

 They may be found in the earth, and in animal or vegetable 

 bodies. Their presence, therefore, in water, is from either 

 one or all of these sources, — it remains with the chemist to 



