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



There is here an increase of weight, partly owing to the salts 

 of the muriatic acid being calculated as in the state of muriates^ 

 though actually obtained and weighed as chlorides, and partly 

 to a portion of the carbonic acid being driven off by heat, or 

 detained in the diluted acid used to extricate it from the carbo- 

 nates. The ascertained weight was .4 of a grain, while the 

 quantity, by calculation, necessary to saturate the quantity of 

 bases found to be in combination with that acid, is .644 of a 

 grain. 



The ochreous sediment, deposited in the channel of the spring, 

 is owing to the iron passing, by absorption of oxygen from the 

 atmosphere, from the state of protoxide into that of peroxide^ 

 and so becoming insoluble ; for, in the state oi peroxide, it is in- 

 capable of remaining in combination with that carbonic acid, 

 through the medium of which it was dissolved while a pro- 

 toxide. 



The difficulties in the results of this analysis are as follows : 



The discrepancy between the quantity of nitrogen stated in 

 chemical works to be capable of being absorbed by water, and 

 the quantity here obtained, which is nearly double of that state- 

 ment. Both the flask and tube were completely filled with the 

 water, so that not one particle of air from the atmosphere was 

 admitted ; therefore, supposing the result to be correct, it can 

 be accounted for only from the great compression, to which the 

 water is evidently subjected under ground, causing it to take 

 up a larger proportion of the gas. 



The quantity of carbonic acid, obtained in Nos. 7 and 9, is 

 also about one-third less than it should have been according to 

 the rules of atomic proportion, but this may partly be accounted 

 for from a portion of it being retained by the diluted acid used 

 to expel it from its state of combination. 



But the greatest difficulty arises from the discrepancy be- 

 tween the quantities of the carbonic acid, obtained from the 

 water by boiling, and by the method in No. 8. In the mode 

 adopted in No. 8., there seems to be no source from which the 

 carbonic acid could be derived, but from the water ; and though 

 the gas got by boiling was collected only over water, yet, as 

 that water was warm, and the tube in which the gas was col- 



