I

Powdered asbestos... 2 parts

Ground baryta...... 1 part

Sodium water-glass solution ............ 2 parts

Mix.

II

To withstand hot nitric acid the following is used:

Sodium water-glass solution ............ 2 parts

Sand............... 1 part

Asbestos............ 1 part

Mix.

III

Asbestos............ 2 parts

Sulphate of barium.. . 3 parts Silicate of sodium .... 2 parts

By mixing these ingredients a cement strong enough to resist the strongest nitric acid will be obtained.

IV

If hot acids are dealt with, the following mixture will be found to possess still more resistant powers: Silicate of sodium (50°

Baumé).......... 2 parts

Fine sand........... 1 part

Asbestos............ 1 part

Both these cements take a few hours to set. If the cement is wanted to set at once, use silicate of potassium, instead of silicate of sodium. This mixture will be instantly effective and possesses the same power of resistance as the other.