106 Rev. Mr Robertson's Analysis of' the Water 



black matter, being subtracted from the eleven-twentieths of a 

 grain, gives .42 of a grain of chloride of sodium, equivalent to 

 .22 of a grain of soda, or .105 of a grain of chloride of sodium, 

 and .055 of a grain of soda in the pint. 



That it was chloride of sodium, was shewn by a portion of it 

 obtained from another quantity of the water, burning, when put 

 on platinum-wire before the blowpipe, with a rich yellow flame, 

 exactly like that afforded by pure common salt. 



The carbonate separated, after being heated to redness, 

 weighed four grains and seven-tenths, which, added to the one 

 grain and seven-tenths formerly obtained, give for the whole 

 saline contents six grains and four tenths, or one grain and six 

 tenths per pint, almost the same result as that in No. 1. 



The small flask containing these carbonates, another small 

 flask with diluted nitric acid, and a capillary syphon, were then 

 placed in the scale of a delicate balance, and accurately counter- 

 poised ; and the syphon being put into the acid, so as to transfer 

 it upon the carbonates, the loss of weight, arising from the escape 

 of carbonic acid, amounted to one grain and six-tenths, or .40 

 of a grain ptjr pint. 



The iron contained in the solution thus made, being peroxi- 

 dized by boihng with nitric acid, was precipitated as in No. 5. 

 In the state of hydrated peroxide, it weighed seven-twentieths 

 of a grain, equivalent to one quarter of a grain of protoxide of 

 iron, or rather more than .06 of a grain per pint. 



8. To ascertain the quantity of free carbonic acid, four pints 

 of the recent water were mixed with lime-water, and the preci- 

 pitate allowed to subside in close vessels. It was collected, 

 and the carbonic acid was expelled from it as above The loss 

 of weight amounted to four grains and nineteen-twentieths, or 

 1.24 grains per pint, from which the carbonic acid in union with 

 the lime, magnesia, and iron, being deducted, there remains .8 

 of a grain for the quantity of free carbonic acid ; but this must 

 surely be incorrect, as it amounts to nearly four times the quan- 

 tity of that which was obtained by boiling the water. The 

 whole of the carbonic acid, however, thus obtained, is nearly in 

 the proportion of two atoms of the acid to one atom of each of 

 the bases with which it is combined ; so that the lime, magnesia, 



