1. Litharge.

Glycerine.

2

Mixed to form a stiff paste, sets and becomes very hard and strong, and is very useful for inserting glass tubes, etc., in iron or brass. For a high heat:

2. Alumina............ 1 part

Sand............... 4 parts

Slaked lime......... 1 part

Borax.............. 0.5 part

Water sufficient. A class of mixtures that can be classified only according to their intended use are core compounds.

I

Dextrine, about...... 1 part

Sand, about......... 10 parts

With enough water to form a paste.

II Powdered anthracite coal, with molasses to form a stiff paste. III.—Rosin, partly saponified by soda lye .... 1 part

Flour............... 2 parts

Sand (with sufficient

water)............ 4 parts

(These proportions are approximate and the amount of sand can be increased for some purposes.)

IV

Glue, powdered...... 1 part

Flour............... 4 parts

Sand (with sufficient

water)............ 6 parts

For some purposes the following mixture is used. It does not seem to be a gasket or a core compound:

V

Oats (or wheat) ground 25 parts

Glue, powdered...... 6 parts

Sal ammoniac....... 1 part

Paper read by Samuel S. Sadtler before the Franklin Institute.