_Willesden Welded Goods_ are prepared by simultaneously dipping two or more sheets of paper and pressing them into one compact homogeneous sheet whilst the surfaces are still in a gelatinous state. In this way a continuous length of fabric of extraordinary durability is produced that is scarcely affected by water, even when heated in it for some weeks at a pressure of 60 lbs. per square inch. As, on drying fabrics treated with cuprammonium solution, the whole of the ammonia in the solution absorbed by them is volatilised, it is necessary, in order to make the process economical, to collect and re-use this ammonia. This is effected by conducting the drying process in closed chambers, from which the ammonia gas is conducted by suitable appliances and recovered. In addition to the advantages already mentioned, it may be stated that Willesden paper is much less inflammable than ordinary paper. Among the many uses to which Willesden goods can be applied, the following may be cited:—Roofs and sheds; huts and tents; partitions; tanks and pipes; damp-proof foundations; underlining slates; sails, awnings, &c. &c. {221} CHAPTER XVII. STATISTICS. _Raw Materials._ The statistics concerning the trade in raw materials for paper-making are not published in a detailed form, all the various kinds of fibre, &c., being grouped under two heads, viz. rags (linen and cotton), and esparto (which embraces other fibres, and probably wood pulps). The figures for recent years are shown in the accompanying tables:— (_a_) Imports of cotton and linen rags: tons. _l._ 1880. 29,642 451,782 1881. 26,773 396,274 1882. 21,200 303,349 1883. 28,543 401,922 1884. 36,233 487,866 1885. 35,470 466,928 (_b_) Esparto and other material: tons. _l._ 1880. 228,580 1,642,903 1881. 238,043 1,626,800 1882. 251,594 1,784,078 1883. 288,549 1,943,732 1884. 260,544 1,638,564 But a portion of these imports was exported again, the figures being as follows:— (_a_) Exports of rags and other paper-making material produced in the United Kingdom: tons. _l._ 1880. 55,792 673,523 1881. 50,488 563,460 1882. 49,352 526,554 1883. 51,293 502,851 1884. 60,924 562,903 {222} (_b_) Exports of ditto of foreign and colonial produce: tons. _l._ 1880. 6,965 102,499 1881. 10,183 146,101 1882. 7,004 84,515 1883. 11,561 121,992 1884. 26,498 274,664 The relative proportions of raw material furnished by the various countries in 1884 (the latest available return) are shown in the subjoined tables:— (_a_) Imports of linen and cotton rags in 1884: