368 APPENDIX V.

5. Estimation of the Argillaceous Earth.

The quantity of argillaceous earth was estimated by precipitation of 50"" of the solution (A) (corresponding to 0"4i99 grm. of ore) with ammonia, whereby the whole of the oxide of iron and argillaceous earth, together with the whole of the phosphoric acid, were precipitated.

Weight of the precipitate = 0-3183 grm., or 70-749 %.

From this is to be deducted 63-786 % oxide of iron + 1-127 % phosphoric acid = 64-913 .

70-749 - 64-913 = 5-836 % of argillaceous earth.

Table of Eesults thus obtaine In 100 parts of Ore there were Water 3-040 Loss at red heat .. 2-929 Quartz and sand .. 19-911 Combined silicic acid 3-468 Oxide of iron . . . . 63-786 44 - 650 % Iron. Argillaceous earth 1-127 Phosphoric acid .. 5-836 0-492 % Phospb.

100-097 i from Ore No. 1.

After being heated at 100° the Ore contains in 100 parts 3-020,67 20-533,21 3-576,34 65-782,50 45-957 % Iron. 6-018,66 1-162,27 0-5073 % Phosph.

100-09 B. Ieon Oee from Darfour, Central Africa. No. 2, found BY KoBERT W. Felkin, Januaey 1880.

The second sample of ore appears to be a loose yellow-ochrecoloured earthy mass, which contained distinct traces of vegetable matter.

Like sample No. 1, the qualitative analysis shows the presence of— a. Oxide of iron.

h. Argillaceous earth, c. Sand.