Chemical Examination of Waters. 15 1 



beverage, and will be tempted to substitute fermented and dis- 

 tilled liquors, to the detriment of health and morals. 



After the physical qualities of a water, we may proceed to ex- 

 amine the impurities dissolved in it. The total amount of dis- 

 solved solid matter is readily ascertained by evaporating a known 

 quantity to dryness at 212", and weighing the residue. It is cus- 

 tomary then to heat this residue to low redness, in order to 

 destroy organic matter ; and after weighing again, we put down 

 so much of the total solid matter as fixed, and so much as vola- 

 tile. The loss on ignition represents the whole of the organic 

 matter, and usually something over. If there be earthy carbon- 

 ates present, or chloride of magnesium, there will be a loss of 

 carbonic acid or chlorine, but with certain precautions this loss 

 may be obviated. If there be salts of ammonia or nitrates pre- 

 sent, there will be loss which cannot be obviated, but in none of 

 the waters under examination did these occur in any appreciable 

 quantity ; and in the following table the volatile matter may be 

 taken in most cases as only slightly exceeding the organic 

 matter. 



The fixed or inorganic portion of the dissolved solid matter 

 requires further examination. In the waters under review this 

 consisted mainly of common salt, with carbonates and sulphates 

 of lime and magnesia, besides a little silica and oxide of iron, and 

 sometimes a minute proportion of phosphate of lime. If the 

 total quantity is not excessive, the exact proportion of these in- 

 gredients is of little consequence. The only practical point to 

 determine is the proportion of the earthy compounds that com- 

 municate hardness to a water. By hardness is meant the pro- 

 perty of destroying soap. It is usually represented in degrees, 

 one degree being that amount of hardness communicated to a 

 gallon of pure water by dissolving in it one grain of chalk ; five 

 degrees, the amount of hardness communicated by five grains of 

 chalk, and so on. 



It is hoped that these remarks will render the appended table 

 sufficiently intelligible. In the first column is given the source 

 whence the water was derived ; in the second column the date of 

 its collection. The third column gives the total solid matter, in 

 grains per gallon, when dried at 212 degrees ; the fourth column, 

 the loss on ignition, slightly in excess of the organic matter ; the 

 fifth column, the fixed residue of inorganic matter. The sixth 

 column shows the quantity of chlorine per gallon, in any form of 

 combination. In most of these waters the chlorine is combined 

 chiefly with sodium, forming common salt ; and if the numbers in 

 column 6 be multiplied by 1'65, the product will show the great- 

 est amount of common salt that could be present in any speci- 

 men, and in most cases may be taken as only a little, if at all, in 

 excess of the common salt actually present, — the chief exceptions 



