1867.] Waters under the influence of Vegetation S^c. 



191 



The results that have been obtained from tliis investigation during the 

 years 18G1 and 1862 are as follows : — 



o r degrees of hardness, or grains of lime-salts, 



1861. March 13 ... . 26-2 < per imperial gallon, in terms of carbonate 



[ of lime. 



May 1....19-5 

 July 3 .... 12-5 



August 1 13-6 „ „ 



Sept. 17 ... . 15-0 



Oct. 8 1.5-5 



^s^ov. 12 18-0 



Dec. 9 20-5 



1862. Jan. 8 . . . . 23-.5 



Feb. 8 25-0 



March 3 . . . . 23*0 



April 3 21-0 



May 2 19-0 



June 4 .... 16*5 „ „ 



July 4 14-0 



August 5 . . . . 12*0 „ „ 



Sept. 2 12-5 „ „ 



The amount of calcareous matter dissolved will be seen to have steadily 

 decreased during the spring and summer months, from its maximum in 

 March 1861 and February 1862 to its minimum in July 1861 and August 

 1862, and then to have increased as steadily during the autumn and winter 

 months. 



Part of this hardness, however, unquestionably arose from the presence 

 in the water of other salts of lime besides the carbonate. To determine 

 how much was the next point for investigation. Portions of the water 

 were taken on several occasions and boiled for a considerable time, filtered, 

 and the volume restored to its original bulk with distilled water. On ex- 

 amining these portions with the soap -test, it was found that the hardness 

 was lowered to 5*6 degrees, equivalent to 5"G grains of carbonate of lime. 

 But inasmuch as carbonate of lime is soluble in water to the extent of 

 2'4 grains in the imperial gallon*, this will be reduced to 3*2 grains, which 

 amount will therefore have to be deducted from each of the above results, 

 in order to arrive at the true quantity of carbonate present in solution. 



The maximum and minimum results will then stand thus : — 



CaO, CO, in the 

 impevial gallon. 



1861. 



Maximum 23-0 



Minimum 9*3 



I JiJnnm.u 



CaO, CO, in the 

 imperial gallon, 

 im 21-8 



18. _. , 



lum 8-8 



* Chemical Eep.ovt on the Supply of Water to the Metropolis. June 17, 1851, by 

 Me.s.'^r.^. Grail am. Miller," and Hol'mann ; and Quarterly Journal of the Chemical Society, 

 vol. iv. p. ."SI. 



T 



