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Chemical Experiments. 
The Vational Educator gives the following three curious 
experiments, which may not be new to the professional chemist, 
but will be of interest to thé student in chemistry :— 
To Light a Lamp with a Snow-ball.—When a small piece of 
potassium, the size of half a grain of corn (Indian corn or maize), 
is dropped into a tumblerful of water, some of the oxygen of the 
water leaves the hydrogen, owing to the intense heat which the 
chemical action produces, and combines with the metallic 
potassium, causing a bluish flame. When a piece of potassium is 
placed on the wick of a coaloil, or alcohol lamp, the flame 
produced by touching the potassium with a bit of snow or ice or a 
drop of water will inflame it. 
Fire under water can be produced by placing a small piece of 
phosphorus in a conically-shaped glass filled with water, and some 
crystals of chlorate of potash covering the phosphorus, and then 
pouring through a Jong tube funnel, or a glass tube, a few drops of 
sulphuric acid down on the mixture at the bottom of the glass. 
Tongues of flame can be seen flashing up through the water. The 
intense chemical action produces sufficient heat to inflame the 
phosphorus under water. When there is sufficient heat and 
oxygen, fire will burn whether in air or water. 
The force of steam-boiler explosions can be illustrated by 
getting a tube made by a tinsmith, say, half an inch in diameter, 
and closed at one end. Put a piece of ice the size of a cherry, or 
half a tea-spoonful of water, into the tube and cork the open end 
tightly. Suspend the tube over a flame, so that the ice melts and 
is converted into steam. The cork will be forced out with a loud 
explosion. Water will produce 1,700 times its volume of steam. 
Photographic Notes. 
A Mucilage for Mounting Prints.—Mr. C. A. Parker gives 
the following for an excellent mucilage for those who always like 
to have on hand a ready means of mounting their prints :—Reduce 
to fine powder, ina mortar, one ounce of very pure gum arabic, 
and add to it three ounces of dextrine, and two fluid ounces of 
water, so as to forma thick paste. Dilute to five ounces, and boil 
over a water-bath for fifteen minutes, stirring continually ; add a 
little ammonia ; this composition may be kept for a long time.— 
Lhe Philadephia Photographer. 
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