The Middlebury register. [volume] (Middlebury, Vt.) 1850-1882, 1876-04-25
Gypsum or Plaster.
BY HON. GEORGE 0EDDEs.


regard to the best methods of using and
testing the value of e. sum as fertil-
izer. intended in that paper, to make
full reply to the many letters OF In
auiry that We receiving, and thus 10
aid inexperienced men in acquiring
knowledge Oh this really important
matter. find that so far from accom-
plishlng my object have only opened
wider the doors Of inquiry, and that
letters come to ME In too great numbers
to receive individual replies. SO l
must again try, through your columns,
TO make all know about plaster ana
its uses ON the farm SO plain that men
who read must understand me.
In further justification for my again
appearing before your readers in regard
to this matter, | will say that the 9TH
or evening, just about the time we usu-
ally 70 to bed, there came to my house
stranger, who said that he was here
to learn of me tse chemical character
o'0"o"deca gypsum, as he ed tc
Of courtV some
.f.e, Ne,; ol Is. iic
c..l.l Use infrrma''N L
..i .c "at TINE had not
-4l se had left the i..-.Jad
.s4.u nat late hour ard found his
49,, ii,fc hoping that at last he shouid
learn all about Onondaga plaster.
what answer could | make to such
all inquirer? ] said to him that it
made no difference where plaster was
quarried, no more than it did where
gold was mined. The only question in
regard to any particular sample of Ell
ther is, "is it pure ?" The place of its
origin is of no consequence whatever.
l referred to Cleveland's Mineratogy,
published in 1922 ut Boston, second
edition, page 204, and found under the
heading Gypsum, the following as its
chemical analysis:
ut is composed of lime, 80 sulphur
c acid, 4G; water % clergyman. A
Eliminated specimen from Onondaga
yielded lime, 50; sulphuric acid, Al (;
water, 2l. In the compact variety,
Gerhard found lime, "a; sulphuric ac-
i /, AZ +; water, Is. 1t is sometimes con-
taminatcd by small quantities of car
Donate of lime, alumina, slick and OK
ide of iron"
Then opened Dana's Geology, pub
lished in 1868, aud at page CT found as
follows OBSERVATION-DISCLOSURES ac-
id, 1851; lime, 32.56; water, 20.99."
/ suppose that this analysis Of Dana
may be accepted as the standard OF
pure gypsum. Or, perhaps we may
use the language of Professor G. G..
Caldwell of Cornell University, in O
late article of the Weekly Tribune
plaster Is sulphate Of lime, or as We
should prefer to call it in accordance
with the more modern fashion among
chemists, calcium sllphate, loosely
united with certain small proportion
Of water, and mixed generally with {
quantity of Impurities containing iron
to which the dark color possessed b.
nearly all the varieties in the market Il
due"
This substance varies considerably
In its formation and outward character
istics. Some specimens are white
some are black, some grey. at II
sometimes mixed with mica, tale, field
spar, &C." find in the books dozel
or more varieties, so called because
mixed with some foreign substance
or because of some variations in tn,
forms of the specialization. But whel
free from impurities, they are all reall,
one thing.
While did not attach much impor
lance to all this "book knowledge,
my visitor did. He took notes iron
-" '.'ri-us authorities, and ar""are'