of a Spring on the Estate of' For del, S^c. 107 



and iron, exist here in the state of bi-carbonates, if such com- 

 pounds be possible. 



This experiment was repeated with a pint of water, which 

 had remained in a bottle for several days. The loss of weight 

 amounted to .95 of a grain, from which the quantity in combin- 

 ation in the carbonates being subtracted, leaves .51 of a grain, 

 more than double the quantity procured by boiling. 



In these experiments, it was observed that the precipitate 

 was frequently buoyed up to the top of the liquid by bubbles 

 of gas. This of course arose from the atmospheric air contained 

 in the water ; and it was the more remarkable, as very few of 

 these air bubbles escaped from the water, so long as it was un- 

 mixed. Qii. Could this be owing to an affinity exerted by the 

 carbonic acid ? 



9. The experiment in No. 7. respecting the loss of weight, 

 arisino- from the expulsion of carbonic acid from the carbonates, 

 was repeated upon the carbonates, precipitated by boiling from 

 two pints of the water. The result was nearly similar, the 

 loss being three-fourths of a grain, or .37 of a grain per pint. 



10. To ascertain the state in which the salts existed, the fol- 

 lowing experiments were made. 



It was found that the excess of carbonic acid did not affect 

 the colour of litmus, and that it could be expelled only by long 

 and violent ebullition. 



When the water has been boiled down to two-thirds of its 

 bulk, a large portion of the magnesia, together with almost the 

 whole of the lime and iron are precipitated. 



This precipitate was redissolved in nitric acid with great ef- 

 fervescence. To some of the solution nitrate of baryta was 

 added, but it gave no trace of sulphuric acid. It became quite 

 black with tincture of galls, and very turbid on the addition of 

 oxalate of ammonia. 



The water from which this precipitate had been deposited, 

 gave, with nitrate of barytes, most decided marks of containing 

 sulphuric acid, and with oxalate of ammonia a very slight ti-ace 

 of lime. It shewed no marks of containing iron, but after be- 

 ing boiled with a few drops of nitric acid to peroxidise any iron 

 which it might contain, it gave unequivocal, though slight, 

 traces of that substance with sulpho-cyanate of potash, and 



