Singular arithmetical Powers of a Child. 1 1 9 



(three times repeated) ex'aporated in the carbonic acid gas? 

 or, in Bucholz's case, might not a smnil portion of carbonic 

 acid gas have remained in the liquor? As Bucholz is one 

 of our most accurate chemists, and therefore I suspected a 

 mistake in my own experiment: 



To ascertain the point, I dissolved in nitric acid in a 

 weighed apparatus 5 grams of white marble coarsely 

 bruised. The gas was conducted through a glass tube, also 

 weighed, and filled with dry muriate of lime kept cold by 

 snow placed around it. The pieces of marble were dis- 

 solved in two hours. The tube had gained so trifling an 

 addition of weight, that I have great reason to believe that 

 the increase was derived from a particle of water that had 

 spurted into it during the dissolution. The total loss 

 was 2-182 grains. The carbonic acid gas had thus departed 

 without any hygronietric or evaporated water; for it did 

 noi deposit anv in the mtiriate of lime. But it might be 

 objected that when the globules of gas are surrounded by 

 the new formed salt and the acid, which strongly retain the 

 water, then all evaporation is prevented. I therefore re- 

 pealed the experiment with the acid diluted by double its 

 weight of water, and dissolved 5 grains of marble therein. 

 The lube now gained during the passage of the gas 0'03 

 grain, and- ihe vessel lost 2-1 75 grains; which, deducting 

 the 0*05, leaves 2-125. I weighed the glass immediately 

 on taking it u|>, and then ^hook it gently for a few minutes, 

 during which it again lost 0-062; so that its total loss be- 

 came 2-157, that is O-OO7 more than in the foregoing trials. 

 It did not lose any further wei<iht in seven hours, slightly 

 covered with paper in - 5-' temperature. This experiment 

 shows, ihat when the nitric acid is too much diluted, the 

 accuracy of tlie resujt n)ay be aflecled iu two ways; partly 

 by water evaporating along with the c<is, and increasing its 

 weight, and partly by a portion of the ga» remaining dis- 

 solved in the diluted Huid, and carry mg with it a further 

 portion of water in its escape. 



i .conclude from these experiments, that carbonate of 

 lime, as well the natural as the artificial, consists of 56-4 

 of lime, and 4.5-6 of carbonic acid, and that it doe> not hold 

 any water of crystallization. 



XXIU. Some Pnrliailars resf)(;cti?ig the arithmetical Powers 

 o/Zekah CoLiiUKN, a Child under Eight Yearsof Jge. 



Tl.DMJoii, ii.cusr '10, Vii'2. 

 HK attention of the |)hilosophical world has been lately 

 atlracleJ bv' the most singular phaenomenon in the history 

 H 4 of 



