* See 
Pe a a i 
328 On the Greensand of New sergey as a source of Potash. 
For more detailed information I wink refer to the elaborate re- 
: _port: of Prof. Rogers before mentioned. I will only state further 
“that the greensand grains are easily pulverized, having only about 
the hardness of gypsum, and that they are decomposed by dilute 
acids, and we then come to the imnediate subject of this paper. 
“Considering thatthe greensand contains the constituents of 
~ alum, with the exception of the sulphurig: acid, it seemed proba- 
ble that by the action of sulphuric acid eee it, a solution would 
be formed containing more, or -less any experiments 
ef the marl, and also that the organic matter interfered in some 
“way. The. solutions. obtained had generally a dark brown color 
s vand a smell resembling “that of formic acid. They contained: 
“mThuch sulphate of protoxyd of iron, and gave a few impure crys-_ 
: ee 
tals. of alum. A portion of the- -greensand was next gently igni- 
:. i which served the purpose of destroying the organic matter, 
_ if any jas present, and also of peroxydizing the iron, thus ren- 
- dering it less soluble in acids. The pulverized and ignited marl 
presented the appearance of a brownish red pow wder. It was 
easily decomposed by dilute salahvaric acid, yielding a solution, | — ‘ 
the contents of which, upon analysis, proved to be principally 
common alum, together with small quantities of iron-alum and 
of the persulphates of alumina and iron. The first erystals of 
most perfectly pure, and upon the addition of a small wpoity of =, 
chlorid of potassium to the solution, it was found, as might have 
been predicted, that all the iron was converted into the uncrys- — 
tallizable perchlorid, the sulphate of potash thus: formed ‘by _ 
double decomposition combining with the free sulphate of alu- 
mina to form common alum; and even in the last. c crops of ¢ : 
tals now obtained little or no iron could be detected. The man- 
ufacture of alum, therefore, by the action of sulphuric acid upon 
previously ignited greensand marl, promises to be suecessful be- 
yond all anticipation. It. is obvious that it will be necessary to 
select varieties of the marl as free as pombe from lime and mag- 
nesia, which would cause a waste o 
My perpen were next directed pee 3 the poe of 
chlorid of potassium. Attempts to form this substance by the 
direct action of I acid upon the ignited marl were 
raises A very large quantity of perchlorid of iron was 
, which would give rise to too great a loss of ac 
Tt was next found that by fusing together greensand and chlo- 
rid of sodium at a red heat, a hard mass was formed, which Uges 
ed with water a solution containing potash ; but chlonid of| o the 
difficulty of separating chlorid of ee from chlor. of 1088 
Ss ge Ren ae ee eee 
