Mix same of the plaster in clear water so it will be a little thick.  Enough plaster should. be mixed to cover the bottom of the dish about 1/2 in. thick.  Pour the plaster into the dish over the print and allow to stand until it becomes quite hard.  The cast can then be removed and the print should be fast to it.  If the print or plaster is inclined to stick, take a knife and gently pry around the edges and it can be removed without breaking.

Prints of any size may be used by having the mold or dish large enough to leave a good margin.  This is a very important point as it is the margin that adds richness to all prints.  Platinum or blueprint papers work well, but any kind that will not stick may be used.  After the plaster has thoroughly dried, any tint may be worked on the margin by the use of water colors; if blueprints are used, it is best to leave a plain white margin.

** Iron Rest for an Ironing Board [288]

A flatiron rest can be made on an ironing-board by driving a number of large tacks into one end of the board.  The tacks should be about 1 in. apart and driven in only part way, leaving about 1/4 in. remaining above the surface of the board.  The hot iron will not burn the wood and it cannot slip off the tacks.  This iron rest is always with the board and ready when wanted. —­Contributed by Beatrice Oliver, New York, N. Y.

[Illustration:  Iron Rest]

** Instantaneous Crystallization [288]

Dissolve 150 parts of hyposulphite of soda in 15 parts of water and pour the solution slowly into a test tube which has been warmed in boiling water, filling the same about onehalf full.  Dissolve in another glass 100 parts of acetate of soda in 15 parts of boiling water.  Pour this solution slowly on top of the first in such a way that it forms an upper layer, without mixing the solutions.  The two solutions are then covered over with a thin layer of boiling water and allowed to cool.

[Illustration:  Crystallization]

Lower into the test tube a wire, at the extremity of which is fixed a small crystal of hyposulphite of soda.  The crystal traverses the solution of acetate without causing trouble, but crystallization will immediately set in as soon as it touches the lower hyposulphite of soda solution, as shown at the left in the sketch.

When the hyposulphite of soda solution becomes crystallized, lower in the upper solution a crystal of acetate of soda suspended by another wire, as shown in the right of the sketch, and this will crystallize the same as the other solution.

** Decoloration of Flowers by Fumes of Sulphur [288]

Dissolve some sulphur in a small dish which will inflame by contact with air thus forming sulphuric acid fumes.  Cover the dish with a conical chimney made of tin and expose to the upper opening the flowers that are to be decolored.  The action is very rapid and in a short time myrtle, violets, bell flowers, roses, etc., will be rendered perfectly white.