These, if properly made, become very tough and tenacious; they stand moderate heat and oil vapors, but not acid vapors.

1.   Finely powdered casein................ 12 parts

Slaked lime (fresh).. . 50 parts

Fine sand........... 50 parts

Water to thick mush.

A very strong cement which stands moderate heat is the following :

2.   Casein in very fine powder........... 1 part

Rubbed up with silicate of soda....... 3 parts

A strong lute for general purposes, which must be used promptly when made:

3. White of egg made into a paste with slaked lime.

A composition for soaking corks, wood, packing, etc., to render them impervious to oil vapors, is:

Gelatine or good glue 2 parts

Glycerine.........0.5 to 1 part

Water.............. 6 parts

Oil of wintergreen, etc., to keep from spoiling.