118 REPORT OF NATIONAL MUSEUM, L920. 



ACCESSIONS DESEKVIXC SPECIAL NOTICE. 



The most important accession of textile specimens received during 

 the year was a series of 10 specimens of silk cartridge cloth which 

 was transferred to the Museum by the Salvage Board of the Depart- 

 ment of Ordnance, War Department. This material is well worthy 

 of special mention, since it is an example of a number of really new 

 things developed solely out of the necessities of the Great Wars 

 conditions, and which are already finding their places as useful 

 articles or inventions under a condition of permanent peace. Even in 

 ordinary times, the development of a really new fabric is an impor- 

 tant matter. 



This war-time fabric, known as silk cartridge cloth, is made en- 

 tirely of silk, and was used in the preparation of separate Loading 

 ammunition for all guns and cannon having a diameter of 4.7 inches 

 and upwards. For these large gnus the propelling charge of smoke- 

 less powder was put into the gun in cloth containers or powder bags. 

 The bags were made of silk cartridge cloth in place of any other 

 fabric, because tin 1 ash resulting from the ignition did not smut the 

 inside of the gun, thus permitting continuous firing without stop- 

 ping to clean out the ba'rrel. Nor did fragments of the silk smolder 

 in the breech of the gun, as would a bag made out of cotton or other 

 materials, thereby igniting prematurely the new charge before the 

 breech was closed and endangering the lives of the gunners. Another 

 advantage of using the silk cartridge cloth for powder bags, was that 

 the silk did not cause a flash at the muzzle of the gun, as would have 

 been the case with cotton or linen, thus avoiding detection of the 

 location of the artillery by the enemy. The silk cartridge cloth 

 which proved itself so indispensable for ordnance purposes was 

 made from various kinds of raw silk, principally waste silk. The 

 waste silk, composed of cut cocoons, immature cocoons, floss comb- 

 ings from the outside of cocoons and tangled masses of silk which 

 could not be reeled in the usual way, was put through a carding 

 process and spun like cotton or wool into what was commonly 

 known as spun silk yarn. This yarn was generally used for the warp 

 or lengthwise threads in the various grades of cartridge cloth. In 

 all the grades of cartridge cloth used by the U. S. Army, the filling, 

 or crosswise threads, was of noil yarn. The noil yarn was spun 

 from short-length fibres left as a by-product in the manufacture of 

 spun silk yarns. The noils were graded, combed and spun in oil, 

 in order to work more smoothly in the spinning of the yarn. All raw 

 silk contains, approximately, 25 per cent of natural gum supplied 

 by the silkworm. This gum was not removed from the raw material 

 used in the making of the cartridge cloth, as it would have been in 

 the case of silk intended for commercial use, for neither the gum 



