OF AETS AND SCIENCES. 



161 



Taking now the naeans of these determinations, and assuming that 

 the chlorine is combined with sodium, while the carbonic acid is dis- 

 tributed among the rest of the base, we obtain as the final average 

 result of the analysis : — 



99.335 



It will be noticed that COg is present in slight excess over the 

 amount required to form neutral ca,rbonates, indicating a small admix- 

 ture of bicarbonate. The water is obviously hygroscopic, and the mi- 

 nute amount of iron an impyirity. Excluding also from consideration 

 the small amount of lime whose relations to the mass cannot certainly 

 be determined, it appears that the three chief ingredients of the crys- 

 talline scale are present very closely in the proportion of their molecu- 

 lar weights. This is shown in the column headed Theory, which gives 

 the amounts of NaXOg and MgCOg corresponding to the amount of 

 NaCl found in the material analyzed, on the assumption that this is a 

 triple salt represented by the symbol MgCOg . Na^COg . NaCl. 



By comparing the determinations of chlorine which form the basis 

 of this calculation, it will be seen that the amount of NaCl must be 

 known with great accuracy, and the column of differences shows that 

 the calculated values of MgCOg and Na2C03 differ from results of 

 analysis within the limits of experimental errors. By withdrawing 



VOL. XXII. (n. 8. XIV.) 11 



