Sulphur in the Pyrite of Iowa Coal. 35 
others. Jn all of the cases where Ca was found, CO, was also 
present, and especially in the first four named. It is believed 
that what is frequently regarded as gypsum in coal deposits, is 
in many cases a mixture of calcium carbonate and sulphate. 
In a large number of examinations of Iowa coals, made by the 
writer in connection with his labors as chemist of the late Geo- 
logical Survey of that State, there were but few cases where 
the application of the test failed to show the presence of CO,,. 
(2) The insoluble—by treatment (1)—iron sulphide was 
thoroughly digested with HC] and KCIO,: the solution thus 
obtained, after being boiled to expel Cl, was divided into two 
yon: Fe,O, and BaSO, determined successively in each ; 
e and S calculated ; and the means of the two analyses taken. 
See columns 4 and 6. 
It was also found by carefully testing the filtrate from the 
precipitate of Fe,O,, that Ca was present in but three cases, 
and then in very small amount. 
The samples for analysis were selected with a view of obtain- 
ing the largest possible quantity of visible sulphide, while not 
excluding that which existed in a form invisible to the eye and 
disseminated through the coal. 
he results of this investigation are given in the following 
Table of Analyses, 
| 3 Sb #22 | seve be soa 
a1) Be | epee cape | bee | Sem, 
8 of BB yo] RBH | wees oe | Bees | gad 
So Ont ° ae) S i 
4) b | Bae | peso | pees | 2 | bl? | 38sce 
Ste Be a jo Bio) bee 4 BRB fee} kd 4 oe oeeee 
2| s3 | aso. | 282 | Bees? | ge | fede | gs28t 
a es | os GBSF | Gorse | Cf BESS — ASasn 
1/19°479| 3-388 | -192 219 | "158 | D.-061 | 45-14 
2|11-722| +785 | -106 121 | 186 | E.-065 | 63-70 
3/11°356| 484 | -19 25 | 278 | E.-053 | 58°53 
4 12°095| -396 | -106 121 | 168 E.-04% | 61°31 
5 | 19-802; 2-767 | -362 414 | 409  D.-005 | 53-05 
6|17-290| 3-819 | B64 645 | 642 D,-003 | 53:23 
7}12°015; 480 | -224 256 | 262 | E.-006| 63°91 
8/15°611/ 1579 | 244 279 | -429 | E.:150 | 63-74 
9 | 22°767| 1-703 | -396 “453 | 407 | D. 046 50°68 
10 /17°693| 1532 | -250 “286 | 284 D. 002 | 53°18 
It will be seen by the sareaes.* table, that in Nos. 5, 6, 7 
1 i e and S correspond nearly 
marked excess of S; while Nos. 1 and 9 give the unexpected 
result of a marked deficiency. 
tis a source of regret to the writer that other duties have 
_ Prevented the making of a larger number of analyses; but it 
