Liquid glue is very convenient because always ready, but is not so strong as hot glue, and has an offensive odor.

Liquid glues are also made by rendering ordinary glue non-gelatinizing, which can be done by several means; as, for instance, by the addition of oxalic, nitric, or hydrochloric acid to the glue solution.
To prepare hot glue, break it into small pieces, soak it in enough cold water to cover it well, until it is soft, say twelve hours, and heat in a glue-pot or double boiler, Fig.

243, p.148.The fresher the glue is, the better, as too many heatings weaken it.

When used it should be thin enough to drip from the brush in a thin stream, so that it will fill the pores of the wood and so get a grip.

Two surfaces to be glued together should be as close as possible, not separated by a mass of glue.