DITTMAE V. EIX. 343 �mon powder. It is not sensitive to concussion, wîll not de- compose by itself, nor cake or pack together, may be readily filled into cartridges, and it matters not wbether the place ■where it is stored be warm or cold, dry or damp. Dualin bas from four to ten times the strength of common powder, anù is stronger than dynamite, an improvement on nitro-glycer- ine. Some of the advantages claimed for dualin over other «xplosive agents are — First, it may be stored, transported, manipulated and applied with less risk than common powder ; second, it may be used in cold weather without first requiring the warming process, which nitro-glycerine and dynamite require, and which frequently become inexplosive at a low liemperature ; third, its explosion does not develop any noxious gases; fourth, absolutely cheaper than either nitro-glycerine or dynamite, dualin is also relatively cheaper than common powder, for, possessing four to ten times the strength of the iatter, its use will proportionately reduce the labor and cost of mining and blasting operations; Jifth, the effect of a dualin •explosion is to tear and rend the material exposed to its action, less than to pulverize it, as is the case with nitro-glyc- erine and dynamite, when applied to mining and blasting operations in coal and rock; sixth, dualin does not necessitate the application of a cap containing fulminate, but may be ■exploded by a fuse, like common powder; seventh, its entire want of sensitiveness to concussion rendors dualin a suitable material for the blasting charge of sbells. �"Description of the process : Dualin consists of cellulose, nitro-cellulose, nitro-starch, nitro-mannite and nitro-glycerine, mixed in different combinàtions, depending on the degree of strength which it is desired the powder should possess in adapting its use to various purposes. Cellulose is prepared by reducing wood of a soft texture (for instance, pine or poplar) "to small grains, resembling sawdust, and treating them with diluted acids, and then boiling them in a solution of soda. After having been thoroughly dried, by a quiok drying process, the cellulose is mixed with — No. 1. Nitre and nitro-glycerine. Or No. 2. Being first changed into nitro-cellusose, by being tfeated with nitric acid (4:8° B.) and sulphuric acid, (66* B.,) ��� �
