How to make gun cotton

Immerse clean cotton wool in a mixture of equal parts of the strongest nitric and sulphuric acids, allowed to cool for one minute, wash in plenty of cold water, and dry in the sun or by a very gentle artificial heat. For soluble guncotton used in making collodion, see PHOTOGRAPHY.

_Lunk's Gun-cotton._

This process gives a gun-cotton which is constant in composition, not liable to change, and of a moderate rapidity of explosiveness. It has been favorably reported on by the Imperial Commision. The following directions are extracted from the specifications of his patent:

First. The cotton or other vegetable fiber is first taken and spun into loose threads of sufficient strength to be easily handled.

Second. The cotton must then be thoroughly boiled in a solution of potash or of soda, in order to remove all greasy substances which the cotton may contain, and after thus boiled it may be exposed to the sun, or wind, or in a heated room, to dry.

Third. The cotton must now be taken into a room heated to 100 Fahr. in order to make it perfectly dry.

Fourth. A mixture is now made containing 1 part weight of nitric acid of 1.48 to 1.50 specific gravity, and 3 parts weight of common sulphuric acid. This mixture must stand in closed earthen or glass jars for several days, or until the two acids become fully mixed and cooled.

Fifth. This mixture of acids is now put into an apparatus containing three apartments; one for the main bulk of the acids, one for the immersion of the cotton, and one for receiving the cotton after being immersed. This apparatus may be made of cast-iron

Sixth. The cotton is now taken and dipped in the acidbath, in said apparatus, in such a manner that every 3 oz. of the cotton must come in contact with 60 lbs. of the mixture of acids, or in other words, the bath must contain fully 60 lbs. of the mixture while parcels of 3 oz. of cotton are being dipped. The parcels thus dipped must be gently pressed, and the acids allowed to flow back into the acid-bath, and the parcels are then put into the third apartment of the apparatus, where for every 1 lb. of cotton there must be 10 1/2 lbs. of the said mixture of the acids. The cotton must remain in this state subject to the action of the acids for 48 hours, and the mixture must always have an equally strong concentration, and must be kept under a uniform temperature by a cooling process.

Seventh. The cotton is now taken out from the acids and pressed, and then put into a centrifugal machine to remove all surplus acids.

Eighth. The cotton is again put into another centrifugal machine, into which a constant stream of fresh water is admitted. This process is intended to remove the last particles of adherent acids.

Ninth. The cotton is now taken and put into a flume or trough, and scoured in such a manner that a running stream of fresh water may pass through and over it; and the same must remain in this situation for at least 14 days. To lessen the time for this operation the cotton may be immersed or saturated in alcohol for the space of 24 hours. This process is also intended to extract all and the last particles of acids that may possibly adhere to the cotton.

Tenth. The cotton is now taken from the stream of water, or if from the alcohol it must be washed, and then boiled in a solution of common soap and again dried. This process is intended to restore the cotton to its original softness and appearance.

Eleventh. The cotton is now taken and immersed in a solution of water-glass of 1 lb. to 2 lbs. of soft water which must be 1.09 specific gravity of concentration. To 1 lb. of cotton 198-1000ths of a lb. of this solution of 46 Beaume is required. The cotton is then taken out of this solution and exposed to the action of the atmosphere for at least 4 days. This process has the tendency to preserve the material, and also to make its explosive qualities less rapid.

Twelfth. The gun-cotton is again washed in soft water free from lime, dried, and then packed in wood or metal boxes for storage or exportation; and may be used for artillery, torpedoes, shells, mining, blasting, small arms, and for all purposes where explosive power is required.

Thirteenth. All other vegetable fibres may be treated and manufactured as herein stated, which process will make the same explosive, like the gun-cotton and adapted to the same purposes.

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