case was fitted a case cover, containing a central circular hole 1 in. in diameter, through which the match head was inserted and from which the smoke escaped when the candle was fired. A cardboard disk containing the match head was placed on top of the case cover. The match head extended down through the hole in the case cover and acted as the igniter for the smoke mixture. A scratch block for igniting the match head was taped to the cardboard disk on one side of the match head and a .-mall strip of wood, the same size as the scratch block, was placed on the other side of the match head in such a manner that they were easily
Fig. 15.—Candle, smoke substitute, in nitration.
removable. The strip of wood, together with the scratch block, lormed a protection for the match head. A metal cover was fitted over the top <>f the candle and «sealed with adhesive tape.
The smoke mixture consisted of potassium nitrate, coal dust, sulfur. Ijorax, and hard pitch, while the match head consisted of a mixture of |K)tassium chlorate, antimony sulfide, and dextrine.
The candle completely assembled was 6}/<i in. high and 33£ in. in diameter, weighed 33 2 lb., was painted black, and was not marked or stenciled in any way.
By drawing the scratch block quickly across the match head, the latter was ignited and flashed into the candle, igniting the smoke mixture. A delay of about 3 seconds occurred between the scratching of the match head and the evolution of smoke. The cardboard disk holding the match head burned off.
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