Dissolve two pounds of strong glue in one quart of water, in a glue kettle, or in a water bath; when the glue is entirely melted, add little by little to the amount of ten ounces of strong nitric acid. This addition produces an effervescence due to the disengagement of hyponitric acid; when the whole of the acid is added, remove the vessel from the fire and leave it to cool.
Glue thus prepared, kept in a stopped flask, will remain good for two or three years.
ENORMOUS STRENGTH OF GUTTA-PERCHA TUBING.
A series of interesting experiments have just been concluded at the Birmingham Waterworks, relative to the strength of gutta-percha tubing, with a view to its applicability for the conveyance of water. The experiments were made (under the direction of Henry Rolfe, Esq., engineer,) upon tubes three-quarters of an inch in diameter and one eighth of gutta-percha. These were attached to the iron main, and subjected for two months to a pressure of 200 feet head of water, without being in the slightest degree deteriorated. In order to ascertain if possible, the maximum strength of the tubes, they were connected with the Water Company’s Hydraulic Proving Pumps, the regular load of which is 250 lbs. on the square inch. At this point the tubes were unaffected, and the pump was worked up 337 lbs., but to the astonishment of every one the tube still remained perfect. It was then proposed to work the pump up to 500 lbs., but it was found that the lever of the valve would bear no more weight.
The utmost power of the hydraulic pump could not burst the tubes.
The gutta-percha being somewhat elastic, allowed the tubes to become slightly expanded by the extraordinary pressure which was applied, but on its withdrawal, they resumed their former size.—London Mechanics’ Magazine, Vol. LI.
CHEAP AND SIMPLE METHOD OF MAKING LEATHER WATER-PROOF.
Two pounds of tallow, a pound of hog’s lard, a half pound of turpentine, and the same quantity of bees-wax are melted together in an earthen pipkin. The boots and shoes are dried and warmed, and the composition is well rubbed into them with a piece of tow dipped into it; the articles being held near a hot fire until they have imbibed as much as they can take up. This mixture is used with very good effect by sportsmen.
Another mixture for the same purpose, which is much used by fishermen, is applied in the same way. It consists of a pound of bees-wax, a half pound of rosin, and the same quantity of beef-suet.—Morfit.