. Bulletin - United States National Museum. Science. \'^ ^'^CV^-AU C\ \< ^7'^. , Rolling, and Transporting bark for use in canoe construction. {Sketches by Adney) Tempering, done after the gum was melted, consisted of adding animal fat and a little finely powdered charcoal. The mixture was then tested by dipping a strip of bark into it and then into cold water. The strip was bent to see if it cracked the spruce gum; if it did, too much tempering material had been added and more gum was required. If no cracking occurred, the gum on the strip was held in the hand for a few moments to
. Bulletin - United States National Museum. Science. \'^ ^'^CV^-AU C\ \< ^7'^. , Rolling, and Transporting bark for use in canoe construction. {Sketches by Adney) Tempering, done after the gum was melted, consisted of adding animal fat and a little finely powdered charcoal. The mixture was then tested by dipping a strip of bark into it and then into cold water. The strip was bent to see if it cracked the spruce gum; if it did, too much tempering material had been added and more gum was required. If no cracking occurred, the gum on the strip was held in the hand for a few moments to see if it became tacky or could be rubbed ofT the strip; if either occurred, more tempering was needed. The method of tempering had many variations. One was to remelt the gum a number of times; this darkened it and made It harder. Red ochre or vermillion were sometimes added, often together with charcoal made from the willow. Instead of spruce gum, in some areas, pine resin was used, tempered with tallow and sometimes charcoal. The Indians in the East sometimes used remelted spruce gum to which a little tallow had been added, making a light brown or almost transparent mixture. Most tribal groups used gum that was black, or nearly so. For repair work, when melted spruce gum could not be procured in the usual manner, hard globules and fiakes of gum scraped from a fallen spruce tree were used. These could not be easily melted, so they were first chewed thoroughly until soft; then the gum \\as spread over a seam. This type of gum would 25. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original United States National Museum; Smithsonian Institution; United States. Dept. of the Interior. Washington : Smithsonian Institution Press, [etc. ]; for sale by the Supt. of Docs. , U. S. Govt Print. Off.
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Keywords: ., bookauthorun, bookcentury1800, bookdecade1870, booksubjectscience
