Sinews for Thread.--Any sinews will do for making thread if the fibres admit of being twisted or plaited together into pieces of sufficient length. The sinews lying alongside the backbone are the most convenient, on account of the length of their fibres. After the sinew is dried straight strips are torn off it of the proper size; they are wetted, and scraped into evenness by being drawn through the mouth and teeth; then, by one or two rubs between the hand and the thigh, they become twisted and their fibres are retained together. A piece of dried sinew is usually kept in reserve for making thread or string.
Glue is made by boiling down hides, or even tendons, hoofs, and horns, for a long time, taking care that they are not charred; then drawing off the fluid and letting it set.
Isinglass is made readily by steeping the stomach and intestines of fish in cold water, and then gently boiling them into a jelly: this is spread into sheets and allowed to dry. The air-bladder of the sturgeon makes the true isinglass. (See "Paste and Gum," p. 332.)
Horn, Tortoiseshell, and Whalebone.--Horn is so easily worked into shape that travellers, especially in pastoral countries, should be acquainted with its properties. By boiling, or exposing it to heat in hot sand, it is made quite soft, and can be moulded into whatever shape you will. Not only this, but it can also be welded by heating and pressing two edges together, which, however, must be quite clean and free from grease, even the touch of the hand taints them. Sheets of horn are a well-known substitute for glass, and are made as follows:--The horn is left to soak for a fortnight in a pond; then it is well washed, to separate the pith; next it is sawn lengthwise, and boiled till it can be easily split into sheets with a chisel; which sheets are again boiled, then scraped to a uniform thickness, and set into shape to dry. Tortoiseshell and whalebone can be softened and worked in the same way.
POTTERY.
To Glaze Pottery.--Most savages have pottery, but few know how to glaze it. One way, and that which was the earliest known of doing this, is to throw handfuls of salt upon the jar when red-hot in the kiln. The reader will doubtless call to mind the difficulties of Robinson Crusoe in making his earthenware water-tight.
Substitute for Clay.--In Damara land, where there is no natural material fitted for pottery, the savages procured mud from the interior of the white-ant hills, with which they made their pots. They were exceedingly brittle, but nevertheless were large and serviceable for storing provisions and even for holding water over the fire. I have seen them two feet high. What it was that caused the clay taken from the ant-hills to possess this property, I do not know.
Pots for Stores and Caches.--An earthen pot is excellent for a store of provisions or for a cache, because it keeps out moisture and insects, and animals cannot smell and therefore do not attack its contents.