tage of chlorides they contain, due no
doubt to the use of hydrochloric acid in their preparation. The soluble
constituents of the ash consist of neutral alkaline salts, but as a rule
no alkaline carbonates, and it is thus possible to demonstrate the
absence of any natural gum in such a compound. We have seldom noticed
the presence of any sulphates in such ashes, but when sulphurous or
sulphuric acids have been used in the starch conversion it will be found
in small quantities.

We have already pointed out that the potash absorption value of a gum is
low and that dextrins give high numbers, but the latter vary very
considerably, and as the starch and sugar present also influence the
potash absorption value, it does not give information of much service.
The following table shows the kind of results obtained:

-----------------------------+----------+--------------+--------------
Sample. | KOH | Starch. | Real Gum.
| absorbed.| |
-----------------------------+----------+--------------+--------------
| | Per Cent. | Per Cent.
Dextrin, 1 | 25.40 | 1.99 | ..
Dextrin, 2 | 19.70 | 13.13 | ..
Dextrin, 3 | 7.57 | 24.72 | ..
Artificial gum, 1 | 19.70 | 10.98 | 9.00
Artificial gum, 2 | 13.70 | 8.05 | 23.50
Starch | 9.43 | 100.00 | None
-----------------------------+----------+--------------+--------------

The baryta absorptions seem to be chiefly due to the quantity of starch
present in the composition:

----------------------------+---------------+-------------------------
Sample. | Starch. | BaO
| | absorbed.
----------------------------+---------------|-------------------------
| Per Cent. | Per Cent.
Dextrin, 1 | 1.99 | 1.75
Dextrin, 2 | 13.13 | 3.53
Dextrin, 3 | 24.72 | 5.64
Starch | 100.00 | 23.61
----------------------------+---------------+-------------------------

The viscosity of a dextrin or artificial gum is determined in exactly
the same way as a natural gum, using 10 per cent. solu