Flashlights 
Metuops oF Usre.—Flashlights may be divided into two 
classes: A, pure magnesium powder blown through a flame; 
and B, magnesium mixed with some substance, rich in oxy- 
gen, which can be fired with a cap, electric or pyrophoric 
spark, etc. The first named are less used at the present time 
than the second class, and they require no comment, as 
special lamps to burn alcohol, benzolene gas, etc., can be 
obtained commercially. 
Gunpowder was one of the first compounds used for firing 
the second class of flashlights ; but it soon gave place to gun- 
cotton or pyroxyline, the usual proportions being pyroxyline 
1 part, magnesium 2 parts. The cotton should be pulled out 
to a loose long tuft and the magnesium sprinkled over it. 
Strips of thin celluloid may be used in the same way, firing 
being effected by a long taper or match tied to the end of a 
stick. The manufacture of flashlights is exceptionally dan- 
gerous, and should not be undertaken by any but experienced 
chemists. 
Mixtures oF MAGNESIUM WITH NITRATES.—In all cases, 
the weight given should be mixed with 1 part of magnesium 
powder. Thorium nitrate, 0.5; this must be dried at 100° C. 
(212° F.) before mixing. Strontium nitrate, 1.5; must also 
be dried. Potassium nitrate, 1.5. Ammonium nitrate, 2; 
not advisable as the salt is hygroscopic, and the mixed powder 
will not keep well. Sodium nitrate, 3. Cadmium nitrate, 1; 
basic cadmium nitrate must be used, which can be made as 
follows: dissolve 100 g (3% oz.) cadmium nitrate in 100 ccm 
(3%4 oz.) hot water in a porcelain dish, add a few drops of 
10 per cent solution of caustic soda, until a precipitate is 
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