entative, the first being the best: 1.
Phosphorus by weight, 1/2 part; potassium chlorate, 4 parts; glue,
2 parts; whiting, 1 part; finely powdered glass, 4 parts; water, 11
parts. 2. Phosphorus by weight, 2 parts; potassium chlorate, 5 parts;
glue, 3 parts; red lead, 1-1/2 parts; water, 12 parts. 3. A German
mixture for matches. Potassium chlorate, 7.8 parts; lead hyposulphite,
2.6 parts; gum arabic, 1 part.

To Find How Much Tin Vessels Will Hold.--For the contents of
cylinders: Square the diameter, and multiply the product by 0.7854.
Again, multiply by the height (all in inches). Divide the product by
231 for gallons. For the frustum of a cone: Add together the squares
of the diameters of large and small ends; to this add the product of
the diameter of the two ends. Multiply this sum by 0.7854. Multiply
this product by the height (all in inches). Then divide by 231 for the
number of gallons.

A Useful Recipe.--For stopping the joints between slates or shingles,
etc., and chimneys, doors, windows, etc., a mixture of stiff
white-lead paint, with sand enough to prevent it from running, is
very good, especially if protected by a covering of strips of lead or
copper, tin, etc., nailed to the mortar joints of the chimneys, after
being bent so as to enter said joints, which should be scraped out for
an inch in depth, and afterward refilled. Mortar protected in the same
way, or even unprotected, is often used for the purpose, but it is
not equal to the paint and sand. Mortar a few days old (to allow
refractory particles of lime to slack), mixed with blacksmith's
cinders and molasses, is much used for this purpose, and becomes very
hard and effective.

Test for Hard or Soft Water.--Dissolve a small quantity of good soap
in alcohol. Let a few drops fall into a glass of water. If it turns
milky, it is hard; if not, it is soft.

Test for Earthy Matters or Alkali in Water.--Take litmus paper dipped
in vinegar, and if, on immersion, the paper returns to its true shade,
the water does not contain earthy matter or alkali. If a few drops of
syrup be added to a water containing an earthy matter, it will turn
green.

Test for Carbonic Acid in Water.--Take equal parts of water and
clear lime water. If combined or free carbonic acid is present, a
precipitate is seen, to which, if a few drops of muriatic acid be
added, an effervescence commences.

Test for Magnesia in Water.--Boil the water to a twentieth part of
its weight, and