(11) Piron has invented a process for tanning textile fabrics, which renders them waterproof, and at the same time, it is said, proof against decay, while their suppleness is not diminished, and their weight not appreciably increased. Arguing from the high state of preservation in which the bands which surround the heads of Egyptian mummies are found to this day, and which are impregnated with a kind of resin, Piron had recourse to the substance extracted from birch bark, and which is now used to perfume Russia leather. When the fine white bark of the birch tree is distilled, it yields a light oil, nearly 1/4 of which consists of the special phenol, or carbolic acid, which gives the well-known odour to Russia leather. It is now found that the residue, or green tar of the birch, which is obtained from Kostroma, yields neither acid nor alkaloid, and it forms, with alcohol, a solution of great fluidity, which, however, when once dried, is unacted upon by alcohol. It is this substance, which will unite with the most brilliant colours, that is used by Piron for treating textile fabrics. Not only does it fill the capillary vessels, but it also coats them with a varnish of great elasticity, which is unattackable by acids and sea water, while it also stands great changes of temperature.
The aromatic odour of articles thus treated drives away insects; there is no space for microscopic vegetation, and neither air nor water can penetrate into the tissues. This process is applicable to all vegetable products, such as sailcloth, cordage, blinds, and awnings.
(12) Sackcloth or canvas can be made as impervious to moisture as leather, by steeping it in a decoction of 1 lb. oak bark with 14 lb. boiling water. This quantity is sufficient for 8 yd. of stuff. The cloth has to soak for 24 hours, when it is taken out, passed through running water, and hung up to dry. The flax and hemp fibres, in absorbing the tannin, are at the same time better fitted to resist wear.
(13) Waterproof Coat
Isinglass, alum, soap, equal parts; water sufficient. Dissolve each separately, and mix the solution, with which imbue the cloth on the wrong side. Dry, and brush the cloth well, first with a dry brush, and afterwards (lightly) with a brush dipped in water.
(14) For Awning Or Apron
(15) Seamen's Oilskins
The material should be fine twilled calico, dipped in bullocks' blood and well dried in a current of air, then 2 or 3 coats of raw linseed oil with a little gold size or litharge in it (say 1 oz. to 1 pint of oil). Each coat should be allowed to dry thoroughly before the next is put on (as before in a current of air, care being taken to shelter it from both sun and rain). Oilskins made in this way, both here and in the tropics, have stood for years.
(16) Waterproofing linen or calico - the manner in which sea-fishermen do coats and leggings. - Whatever the article is, let it be stretched on a table. Make very thick paint of whatever colour is wished. An invisible green is, perhaps, as good as any. Take a large lump of common brown soap, pretty freshly cut from a bar, in the left hand, and every time you replenish the brush with paint rub well on the soap, and take up as much as possible, and rub well on one surface of. the calico or linen. It will take long to do, and should be hung in the windiest place you can find. Summer is the best time, but a month will see it in very usable order, and you will have as supple and perfectly waterproof a garment as paint can make. After wearing a few times, a second coat would be advisable, which will dry in half the time of the first, and must be done in the same way.
(17) For Canvas
A solution containing equal parts by weight of gelatine and chrome-alum. It is not advisable to mix more of the solution at once than is sufficient to give the canvas one coat, as, if the mixture once sets, it cannot be reliquefied like a plain solution of gelatine, and hence, if the quantity of canvas to be waterproofed is but small, it would, perhaps, be preferable to coat with plain gelatine solution until quite impervious to cold water, and then to thoroughly soak, say for 24 hours, in a strong solution of chrome-alum.
(18) For Sail-Cloth
Grind 96 lb. English ochre with boiled oil, and add to it 16 lb. black paint. Dissolve 1 lb. yellow soap in 1 pail of water on the fire, and mix it while hot with the paint. Lay this composition, without wetting it, upon the canvas, as stiff as can conveniently be done with the brush, so as to form a smooth surface; the next day, or the day after (if the latter, so much the better), lay on a second coat of ochre and black, with a very little, if any, soap; allow this coat a day to dry, and then finish the canvas with black paint.
(19) For Woollens
Boil 4 1/2 oz. white soap in 2 1/2 gal. water, and separately dissolve 5 3/4 oz. alum in 2 1/2 gal. water. Heat the 2 solutions to 190° F. (88° C), pass the fabric first through the soap bath and then through the alum, and finally dry in the open air.
The manner of making oil-cloth, or "oil-skin," was at one period a mystery. The process is now well understood, and is equally simple and useful. Dissolve some good resin or lac over the fire in drying linseed oil, till the resin is dissolved, and the oil brought to the thickness of a balsam. If this be spread upon canvas, or any other linen cloth, so as fully to drench and entirely to glaze it over, the cloth, if then suffered to dry thoroughly, will be quite impenetrable to wet of every description. This varnish may either be worked by itself or with some colour added to it: as verdigris for a green; umber for a hair colour; white-lead and lampblack for a grey; indigo and white for a light blue, etc. To give the colour, you have only to grind it with the last coat of varnish you lay on. You must be as careful as possible to lay on the varnish equally in all parts.