A strong cement, used as a stone cement, is:

1.   Rosin.............. 8 parts

Wax............... 1 part

Turpentine.......... 1 part

It has little or no body, and is used in thin layers.

For nitric and hydrochloric acid vapors:

2.  Rosin................ 1 part

Sulphur............ 1 part

Fire clay............ 2 parts

Sulphur gives great hardness and permanency to rosin lutes, but this composition is somewhat brittle.

Good waterproof lutes of this class are:

3.   Rosin.............. 1 part

Wax............... 1 part

Powdered stone...... 2 parts

4.  Shellac............. 5 parts

Wax............... 1 part

Turpentine.......... 1 part

Chalk, etc........8 to 10 parts

For a soft air-tight paste for ground-glass surfaces:

5.  Wax............... 1 part

Vaseline............ 1 part

6.  A strong cement, without body, for metals (other than copper or alloys of same), porcelain, and glass is made by letting 1 part of finely powdered shellac stand with 10 parts of ammonia water until solution is effected.

Lutes VII. Rubber

Because of its toughness, elasticity, and resistance to alterative influences, rubber is a very useful constituent in lutes, but its price makes its use very limited.

Leather Cement

1.  Asphalt.............     1 part

Rosin..............     1 part

Gutta percha........     4 parts

Carbon disulphide. ..   20 parts

To stand acid vapors:

2.  Rubber............     1 part

Linseed oil..........     3 parts

Fire clay............     3 parts

3. Plain Rubber Cement

Cut the crude rubber in small pieces and then add the solvent. Carbon disulphide is the best, benzol good and much cheaper, but gasoline is probably most extensively used because of its cheapness.

4.   To make corks and wood impervious to steam and water, soak them in a rubber solution as above; if it is desired to protect them from oil vapors, use glue composition. (See Section IX.)