344 FEDERAL REPORÏER. �it is then mixed -with nitro-glycerine. No. 3. The dried cel- lulose is mixed with anhydrous glycerine, until the mass be- comes of the consistency of thick broth. This is gradually trea'ied to a bath composed of a mixture of sulphuric acid (66° B.) and nitric acid (48° B.) of eight to ten times its quantity, 'during which process the greatest care must be taken to stir the heated mixture and cool it. The stirring is con- tinued for at least half an hour, after which the mixture is placed in a water bath of ten times its quantity. The acid water being repeatedly drawn off and replaced by pure water the mixture is now placed in a bath of diluted soda iye. In this it is stirred from one to two hours, again washed in pure water, and then rendered anhydrous by means of hot water heating, and treating it with concentrated sulphuric acid and chloride of calcium. After having been rendered anhydrous, it is mixed with cellulose, prepared by process described under No. 1, 2 or 4, until a dry and not very greasy powder is obtained. The dust is sifted out, and this, if packed into cartridges, is serviceable. The powder remaining possesses the advantages above enumerated. No. 4. The cellulose is charred, finely pulverized, boiled in concentrated nitre Iye, and, after soda has been added, is rapidly dried, and mixed with nitro-glycerine or dualin, prepared by process No. 1, 2 or 3. No. 6. The process of preparing nitro-starch, another ingredient of dualin, is also new. It will prevent the forma- tion of lumps after the starch has been subjected to the acids, and also render the dried preparation less sensitive to dampness, a. Starch is thoroughly dried until it assumes a yellowish brown color. It is then finely pulverized and mixed with anhydrous glycerine. The mass is slowly placed in a mixture of nitric acid (48° B.) and sulphuric acid (66° B.) of ten times its quantity, during which process the greatest care must again be taken to stir the mixture and cool it. The stirring is continued for half an hour, when the mixture is placed in a water bath. The acid water being repeatedly drawn off and replaced by pure water, the mixture is now placed in a bath of soda Iye, then placed in another water bath, and finally rendered anhydrous by means of hot water ��� �
