Chemistry and Physics. 405 
On the Condition in which Carbon = in Steel. ABEL 
and Drrrina have made a series of experiments in the hope of 
obtaining Sikoruiatinn on ais condition in whieh carbon exists in 
Steel as it is left by the cold-rolling, as well as in its hardened, 
annealed and inter sity conditions. Two series * experiments 
were made. In the first series the steel was in t orm of 12 
disks 2°5 yest in gis ta and 0°01 inch thick, sak weighing 
about 6°5 grams. In one disk, hardened, the silicon -was deter- 
mined to be 0° 20 per aeat A cold-rdlled disk gave 1'108 total 
carbon, a hardened one 1°128, an annealed inside disk 0-924, and 
a similar outside one 0: 860, ‘Three disks were used for estimating 
the so-called uncombined carbon by gently heating them for t 
hours in 100° of hydrochloric acid of sp. gr. 1-10. The ould 
rolled one left ms 096, the annealed inside one 0°052, and the hard- 
ened one 0-035 per cent carbon. Three others were placed in a 
cold erie solution of potassium dichromate acidulated with 
Hr ° of sulphuric acid, being supported on sieves of platinum gauze. 
he cold-rolled, the- annealed and the hardened disk each left a 
small quantity of black particles which appeared spangly under 
the microscope and which were attracted by the magnet. Upon 
9178 and 0-70; calculated on the total weight of the disks. 
Thus the chromic acid treatment has left nearly the whole of the 
carbon from the cold-rolled and the annealed disks in the form of 
only about one-sixth of the total carbon was left undissolved by 
the chromic treatment. The last disk was submitted to the 
action of a chromic solution sane a large excess of sulphuric 
acid. The black residue gave on analysis 0°84 carbon = 17104 
sao res ih one ber carbide had broken down. _ To study the 
Series ror experiments was made. The st zeal used was in the form 
of a thin sheet 0-008 inches thick, weighing 175 preton cold- 
rolled from an ingot melted from cemented blister steel. On 
analysis it contained 17144 carbon, 0°166 silicon, and 0°104 man- 
ganese. Four experiments were made, seer! 7 to 75 grams of 
Steel being used in each, the strength of the chromic solution 
e Ww t 
nce th 
appear to sustain the view that the carbon in this steel is 
not esl, diffused sy through the mass of steel but 
