Composition.
| Silica | 11·30 | 9·30 | 27·75 | |
| Chlorine | 1·53 | 1·60 | 0·79 | |
| Potassa | 37·46 | 41·63 | ||
| Soda | 1·40 | 1·12 | ||
| Ferric oxide | 1·80 | 1·12 |
| 16·00 |
| Alumina | 5·13 | 4·26 | ||
| Manganic oxide | 2·10 | 1·30 | ||
| Lime | 9·43 | 8·18 | 19·66 | |
| Magnesia | 8·00 | 5·33 | 11·20 | |
| Phosphoric acid | 12·27 | 16·62 | 15·80 | |
| Sulphuric acid | 4·18 | 3·64 | 1·10 | |
| Carbonic acid | 5·40 | 5·90 | 6·70 | |
| 100·00 | 100·00 | 99·00 |
“Tea dust” affords a high proportion of ash, sometimes amounting to 20 per cent., the composition of which is usually strikingly different from that of the ash of ordinary tea. It is deficient in potassa and phosphoric acid, and the amount of ash insoluble in water and acids is very excessive, as is shown by the following analysis, made by the author:—
Ash of Tea Dust.
| Per cent. | |
| Insoluble in acids | 60·30 |
| Alumina and ferric oxide | 6·60 |
| Lime | 5·10 |
| Magnesia | 7·89 |
| Potassa | 11·00 |
| Soda | 2·51 |
| Sulphuric acid | 1·23 |
| Chlorine | 0·63 |
| Phosphoric acid | 4·73 |
| 99·99 | |
| Ash insoluble in water | 80·00 |
PLATE II.
TEA LEAVES.
The portion of ash insoluble in acids consisted of silica, clay, and soapstone, indicating that the ash of tea dust is largely composed of the mineral substances employed for “facing” purposes.