[ i84 ] 



^ 2d. The difference betwixt the given extratabular acid contents, 



52,38, and the next lower tabular acid contents 51,78 is ofi = d 



then d, the quantity to be added to the lower fp. grav. is found by 



. . , , Dd' 0,0088 X 0,6 0,0528 „ 



the formula a = -.fr; =. = - — - — = 0,0058 



U 0,9 0,9 



1^5385 

 Now + 0,0058 and that found by Hahn is 1,545. 



= 1,5443 



This it is true would be the fp. grav. at 60*^, and after 3 days 

 reft (the time I allowed for the penetration of the mixtures men- 

 tioned in my tables,) and it does not appear what the temperature 

 of Hahn's mixture was when he took its fp. grav. if it was 44^ (the 

 temperature of his oil of vitriol) it is poffible that the cold without 

 exad penetration might produce an effed equivalent to that which 

 time would produce by penetration. 



2d Experiment. 



In this Hahn added 400 grs. of water to the 1 200 grs. of the 

 foregoing mixture, and confequently the new mixture weighed 

 1600 grs. and contained the fame quantity of real acid as the fore- 

 going, iliat is 628,36 grs. he found its fp. grav. when cold to be 

 1,38,40. 



y^/>plicatioff. 



