Explosives 



Explosives are solids or liquids which can be changed almost in- 

 stantaneously by a spark, great heat or powerful shock into gases having 

 many times the volume of the explosive in its original form. Coal and 

 wood are changed slowly into large volumes of gas by burning ; water is 

 changed into a large volume of gas (steam) by heating it. This is the 

 whole theory of explosives and much in their use, which would otherwise 

 seem difficult to explain, is easily understood if this theory be borne in 

 mind. 



Blasting explosives are divided into two classes, namely: High 

 Explosives and Low Explosives. High Explosives are more commonly 

 known as " dynamite," including all of those explosives which can be 

 properly detonated only by means of an intermediate agent such as a 

 blasting cap or electric fuze and not by simple ignition. Blasting powders 

 are classified as low explosives and are exploded by a spark. 



Blasting Powder 



Blasting Powder is black and is produced in granulations or grains 

 of various sizes. It is packed in bulk in steel kegs containing twenty-five 

 pounds. Although it is invaluable for many kinds of coal mine, quarry 

 and general excavating, it is not generally applicable to any blasting 

 about the farm except for splitting logs as described on page 137. 



Dynamite 



Dynamite differs from blasting powder in that it detonates with 

 much greater rapidity and has a greater shattering effect. The most 

 important properties which contribute to the effect of dynamite are 

 strength or disruptive power and quickness or shattering poiver. The 

 other principal factors in the usefulness of dynamite are its stability or 

 keeping qualities and such qualities as may tend to make it safer to 

 handle. These essentials can only be secured and maintained by the 

 employment of the highest quality of ingredients, greatest care and 

 attention, expensive and complicated machinery, skillful labor and super- 

 vision, long experience, and continued tests. The Du Pont Company 

 fulfills all of these requirements. It has been engaged in the explosive 

 manufacturing business since 1802, has factories in all parts of the United 

 States and no other manufacturing concern in this country maintains a 

 greater number of technical chemists than are engaged at the Du Pont 

 laboratories, who test daily the output of the factories to prevent devia- 

 tion from standards, and constantly study and experiment with explo- 

 sives in order to improve them. 



Furthermore, a corps of experts in the use of explosives is main- 

 tained, not only to study the exact requirements of explosives in the 

 various fields and differing conditions, but to demonstrate their qualities, 

 action and method of using them. 



The Du Pont Company manufactures numerous kinds of dynamite, 

 each having some particular property which makes it different from any 

 other kind. Almost every kind is made in different strengths. Some 

 kinds will burn if a spark falls on them and all kinds can be burned if 

 put in a fire. Don't, therefore, leave dynamite where it can be ignited 

 any way, because, when hot it is very sensitive and often explodes. 



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