86 
THE TROPICAL AGRICULTURIST. [Aug. i, ix 9 
carbon,, which is weighed. I found the process 
answered for the purer sample-; j hut, when much 
gritty matter was present, a portion was apt to 
he left, making the carbon appear too high. In 
my subsequent analyses [ reverted to the older 
process, in which the carhon is estimated by the 
loss of weight, when the mineral is binned in 
oxygen gas. The following samples, analysed 
in this way, were inferior in point of percentage 
of carbon to those already quoted :— 
Analyses of Ceylon Plumbago Dust. 
Loss on ignition in air 
Ash 
Graphitic carhon 
Sulphur 
per cent. 
31 
2-2 
35 
1-8 
22 4 
22-6 
28-4 
16-2 
74 o 
74-8 
68-1 
82 '0 
100-0 
100-00 
100-0 
1000 
17 
•07 
•22 
•45 
The following are a few more analyses of Ceylon 
plumbago dust in which the percentage of iron, as 
well as the other ingredients was determined : — 
uo x t- 
rn l-» © 
Ft X 
00-001 
CO r-H 
CD 11 
(>1 
18 0«J 
M CO © 
0 
p 
b 
0 
ci © 
CI re 
i-1 o >o 
OTOO 
" 
OS 
0 
9 
0 
0 
« O 
OOO 
<n t-b 
* 
0 
0 
b 
0 
X t» 
O l> 
1-1 X I— 
.X 
s 
9 | 
OOO 
OOO 
ih ib re 
0 
0 
b 
0 
rH 
T" 9 
1- co 
os 
1 
;! 
0 
<M 11 
CN p 
ce 
c 
Ki B 
C o 
.2 : •? 
£ ' s 
.2° « 
c 3 
o 
C ^ J-< 
r-i<qO 
It will be observed from the above figures that, 
although the sulphur in whole or in part exists 
in plumbago as sulphide of iron, these two elements 
sulphur and iron do not bear any fixed proportion 
to each other, there being always excess of iron in 
other forms than sulphide. 
The following are analyses of graphites of 
different countries by V. Kegnanit C, AY heeler, and 
by C. Mene, quoted from Dana 8 Mineralogy -.- 
Country. 
Canada (I) 
» (ID 
„ (HI) 
Siberia 
Albert mine, 
Siberia .. 
Do ... 
Percentage composition. 
0 , 1 
Carbon. 
Hydro- 
gen. 
Ash. 
86-8 
•5 
126 
7635 
•70 
23-4 
98 56 
1-34 
•2 
89-51 
•60 
10-4 
94-70 
5-3 
9717 
283 
Authority. 
V. Kegnanit 
do 
do 
do 
C. Wheeler 
do 
3 
■ ■ 
3 »-. 
;= c 
a — 
At"\3 
c S3 
: 11 p I- 1 -. 11 -r si 
«-t " — 11 ii 
2 1 1 21 1 
CD I i ' ©» A 9t »< * <-« 
c 
re ci n _ x 11 ms x li x ei 7- 
© II X CD I- © CO CD 1- 1- ITS ce X X 
1 - ci ui p to 11 o co •— n 1 - — x »-i x 
SI IC X r 
c£ 
11 © C © 11 ii 11 © 11 © II © X © c 
[--r.'MQCi CI X — 11 51 II CN 
' Ai r* ii fh 11 1 , — cd c 1 re 11 ci 
a 
o 
3 
o 
"5 "it 
8 - 
© H l~ © X II t - II 71 11 i~ y ia — "1 
1-1 LI © I- 71 © 11 n co CO O X '1 I - 
i- -e — ■ f©xox©x — ©coi- 
—> ci — Cl cc 11 ri 11 -r cr ci rr n -t 
n ii 11 11 ii ii 11 11 ii ii 61 11 ii ii ii 
£ 'C . ce 
5 -»=> ci — 
— £ •= 3 
S SP« 3 E a . pi. 
S ~< ?. 3 : cecs - : s 
S J ?c5 J! 3 - ra 5 
1 2 2 c ©.g St-S ll'ta g e- S t- s 
In the preceding table of analyses. Ceylon 
plumbago must have been represented by a very 
poor sample. 
In his article on plumbago in the Journal 
of the Ceylon Branch of the Ko3 al Asiatic Society, 
1885, Mr. A. M. Ferguson, c-M.c;., quotes from an 
article on plumbago in the " Mineral resources of 
the United States," by Mr. John A. Walker 
tome analyses of Canadian and Ceylon graphites 
which do full justice to the Ceylon article. These 
