As the Navajo silversmiths dwelt in small huts or temporary shelters which they might move away from at short notice, they were forced to build low forges directly on the ground, obliging them to crouch down while working.[48] In this respect the Pueblo artisans had a considerable advantage, since their spacious dwellings made it possible for them to set their forges solidly in a frame high enough to enable them to do their work standing. A considerable number of tools and appliances are in the workshop of the Navajo silversmith; most of them, however, of rude fabrication and not well adapted for fine and accurate work. He deserves the more credit for the quality of work he is able to produce. The following is a pretty full list of the outfit in such a workshop: Forge, bellows, anvil, crucibles, molds, tongs, scissors, pliers, files, awls, cold chisels, matrix and die for moulding buttons, wooden stake, basin, charcoal, tools and materials for soldering (blow-pipe, braid of cotton rags soaked in grease, wire, and borax), materials for polish (sandpaper, emery-paper, powdered sandstone, sand, ashes, and solid stone), and materials for whitening (a native mineral substance--almogen, salt and water).[49] It has been noted that the Navajos had not acquired the art of making an air chamber of the mouth in operating the blow-pipe, but blew with undistended cheeks, the result being an intermittent flame. The latter is furnished by burning a thick braid of cotton rags soaked in mutton suet or some other similar kind of grease. For the polishing work, the emery paper is sparingly used because of its cost. After all the preliminary polishing has been done with sandstone, sand or ashes, the finishing is done with emery-paper. For the blanching of the silver the hydrous sulphate of ammonia, termed almogen, is used, the silver being bathed in a solution of this, with the addition of a little salt. The blow-pipe is usually made by beating out a piece of thick brass wire into a long flat strip, which is then bent into the requisite form.