512 
THE TROPICAL AGRICULTURIST. [^Eh. i, 1894. 
",£l»emistry : Theoretical, Practical and Analyti- 
cal rei)resents the percentage composition of some 
of theiri 
Analyses of Mineral Phosphates. 
Water 
Loss on ignition 
Phosphoric acid 
Lime 
Magnesia 
I'otasli 
Soda 
Ferric oxide .. 
Alumina 
Carbonic acid . . 
Sulphuric acid.. 
Chlorine 
Fluorine 
Silibeous matter 
0 s ph o ri c'l 
acid reckon- 1 
ed as trical- j 
cic phospatej 
Carbonate of 
calcium 
iiime for 100 
phos. acid .. 
is 
j -90 
3.5-69 
46-39 
•74 
-.36 
1-29 
) -.53 
none 
•29 
1-62 
11-62 
77-90 
none 
1.30 
•91 
.33-27 
45-56 
10-38 
72-62 
1.37 
Sp.anl'^h 
Phosphorite. 
3 O 
3-59 
33-38 
4716 
trace 
259 
•89 
4-10 
•57 
3-71 
4 04 
26-62 
1-00 
28-67 
40-60 i 43-30 
1-4«| -95 
•08 
•64 
2-18 
-63 
•50 
4-67 
•90 
•67 
20-92 
72-87 
931 
141 
6'2 59 
1062 
205 
6-82 
•91 
8-19 
58^11 
15-50 
142 I 163 
According to Mr. Pringle (Tropinil Agi'lculfur- 
ist 1891) both bone ash .and mineral i>hosj>hates, 
which are to be applied directly to the soil as 
manures, should be in .a state of division, such 
that 90 per cent, passes througii a sieve of 80 
meshes to the linear inch. The s.anie agricnituial 
chemist say.s : " Of miner.al phosphates high c-l.ass 
" Spanish called Estram.adurite, has from 75 to 82 
" per cent, pho.sphates ; inferior qualities fire 
" often in the market with only 50 per cent. 
" or so in them. Canadian and Norwegian apatites 
■" and Aiuba phosphate are generally very lich, 
" having sometimes as much as 90 jier cent. 
'• tricalcic phosphate. There are a great number 
" of others ; but these are the most suitalile, and 
" I prefer Aruba, as it is ,as soft and as easily 
" deconiposed as bone ash, and is generally 
' " cheaper." 
Deposits of guano are met with which have 
parted with nearly all their nitrogen, and are 
valued on the basis of their phosphoric acid. 
Some of these guanos contain phosphoric acid 
equivalent to upwards of 70 per cent, tricalcic 
phosphate. These, <as well as bone ash and 
muieral phosphates, are used in the manufacture 
of superphosphates. From phosphatic guanos, 
Tjy tieatment with sulphuric acid, are prepared 
the superphosphates that are richest in soluble 
phosphates. As these guanos are free from excess 
of lime, and contain almost no iron and alumina, 
practically the whole of the phosphate can be 
rendered soluble, and they yield a superphos- 
phate, containing from 40 to 45 per cent, of 
^Holuble phosphate, i.e., tricalcic phosphate rendered 
soluble. Bone ash contains <a little lime not 
combined with phosphoric acid, which is con- 
Verted iuto gypsum, thus adding to the won- 
phosphatic ingredients ; hence bone tish itujier- 
phosphates are not quite so rit-L in soluble 
phosphates as thowe iiia<le from high ( lass pho^ 
jdiatic guanos, still the su|Kfrpho..phate^ made 
from iKjneash are of excellent quality, and may Ik- 
reckoned to yield from 35 to 40 |>ei cent, of 
soluble i)hosphat«s. Mineral jilioNphat>es yii ld 
suj)eii)hosphates rich in soluble |>lioi>pliate». in 
jiroportion to the richness of the mineral phoh- 
pliate, to the fineness of the grinding of the mineral 
and to its freedom from iron, aluminum, and 
calcium carljon.ate. A range of from 20 to oxer 
40 ]»er cent, of soluble phoi-phate may l>e look»-d 
for in this class of su|>erphospliate. From Caiolina 
river phosphate 30 i>er cent, and from CiuiilHidge 
coproiite "25 per cent, holuble pbo«*|>li«t«M «re 
said to be fair yields. 
The following is Krfx-ker's analyses of a 
sui)eriiliospliate made from liaker guano : — 
Analysis of SupfrphoKphatc. 
l>er et^nl. 
Moisture ... ... ...-j 
Chemically combined water ...j27-<J<i 
Combustible matter ... 
• Soluble phosphoric acid ... 21 -31 
t Insoluble do ... ... 1-(I5 
Sulphuric acid ... ... 24*65 
Lime ... ... ... 23-2<) 
Magnesia ... ... ... 
Alkalies ... ... ... -49 
Insoluble matter ... ... j-WJ 
lOOOO 
• Equal to tricalcic j>hcsphate rendered 
soluble ... ... ... 46-52 
t Equal to tricalcic phosphate ... 2*29 
The following are the analyses of two samples 
of superphosphate imported to Ceylon : — 
Analyses o;f Superphospliat^s imported to Ceylon. 
Moisture 
Chemically combined water and 
Combustible matter 
* Soluble pliosphoiic acid... 
t Insoluble phosphoric acid 
Sulphuric acid 
Lime 
Magnesia, alkaline salts and 
oxide of iron ... 
Insoluble matter 
j»er cent. 
15-66 
... ■ l-,50 
... 29-06 
... 23 35 
• I 2-:i.5 
... 6-30 
100-00 
* Equal to tricalcic phosphate ren- 
dered soluble ... ... 34-2) 
t Equal to tricalcic phosphate ... 3'2r 
The following is a bettei sample of sri]>eridioB- 
phate, the results being also reported in a different 
form from the above : — 
per cent. 
Moisture and other volatile matter .. 24-10 
* Monocalcic phosphate (biphospliate) 26-84 
Insoluble phosphate of lime ... 1-24 
Calcium sulphate (hydrated) ... 4639 
Aikaline salts ... ... j-qs 
Insoluble matter ... .„ -35 
100-00 
42-02 
* Equal to tricalcic phosphate 
The following analyses by Tatloek represent 
superphosphates in the most concentrated form 
which has come under the author's notice. They 
were niauufactmed iu the year 1892 ;— 
