Prof. Eggertz on determining combined Carbon. 375 
Suppose that 1 gram of each of two steels (@ and b) have 
been dissolved, and that the volumes of the two solutions 
tube is in contact with the warm water; a movement takes 
place in the acid which favors its reaction upon the metal ; a 
slight disengagement of carbonic acid from all the particles 
carbon may be observed. The operation should always 
ne gaat under the same circumstances as to heat and length 
of time 
| 3 The evolution of gas having ceased (in operating upon steel 
the reaction must continue two to three hours), lace the tube 
in a large vase filled with water to bring the solution always to 
the same temperature. This precaution is indispensable be- 
Cause the same liquid is darker when warm than when cold. 
erward, pour off as exactly as possible the clear liquid into 
@ graduated burette. Upon the black residue remaining in the 
tube pour some drops of nitric acid and heat carefully over a 
lamp. If there is no further liberation of gas, the residue con- 
sists of nothing but graphite or silica. (Cool the new solution 
normal solution, 100 ¢ 
