Intercommunication / Mm. musteohjeita

Manufacturer and builder 5, 1871

[Kysymykset ja vastaukset poimittu eri palstoilta yhteen]

[96] Boot-Blacking that will not dry in the Box. [Q:] - Add some chloride of calcium, glycerine, or any other compound which prevents drying; you must try yourself which of the several similar substances suits your purpose best.

[98] Silvering and Gilding Woven Fabrics. [A:] - Prepare a solution of nitrate of silver, drop it gradually liquid ammonia till the white cloud first formed is just dissolved again. Then place your woven substance for two hours in this solution, take it out and dry it. When dry, expose it to a current of hydrogen gas. This will reduce the silver to the metallic state and make it a good conductor. It is then easily gilded by the usual electro-plating process, or silvered, if the appearance of the silver is not brilliant enough. This method was patented in England in 1857, and the patent is, therefore, about run out.

[99] Writing-Fluids. [A:] - We can hardly see why our correspondent is particular about hte bluish-green shade, as it is the precailing opinion nowadays that an ink which is black at once is far prederable to one which, when first used, is often so light a tint as to oblige the writer to wait some little time in order to see what he has written. Indeed, this peculiarity of ordinary writing-fluids is considered a defect, but one which is due to the prescriptions and mode of combination now in use. The reason why the ink remains light when kept in corked bottles and changes to a darker hue when exposed to the atmosphere is as follows: most kinds in use at the present day are made of the so-called copperas, or really, the proto-sulphate of iron, FeO, SO3, which, with a decoction of gall-nuts, logwood, or any other substance containing gallic or tannic acid, forms a pale black, or rather bluish solution. By exposing the writing to the atmosphere, the iron compound will absorb oxygen and change into the persulphate of iron, which is a sulphate of the sesqui-oxide, (Fe2O3, 3SO3,) and which forms, with the tannic acid, a black substance. We have before us a collection of prescriptions amounting in number to over a hundred, from which the following, which are quite celebrated in Europe, are selected;

No. 1. Geizzler's Black Ink. One lb. crushed gall-nuts, 10 ozs. copperas, 3 ozs. gum-arabic, 1 qt. vinegar, and 7 qts. water. Let the mixture stand for two weeks, and pour off the liquid, which is the ink. The residuum at the bottom will be the gall-nuts with some ink adhering, and may be used again by adding 3 pzs. copperas, 1 oz. gum-arabic, and a corresponding quantity of water and vinegar - keeping the preparation in a warm place.

No. 2. Haenle's Black Ink. This ink, it is claimed, does not attact steel pens. Two parts crushed gall-nuts, 1 part gum-arabic, 1 part copperas, and 16 parts distilled or rain-water, adding a few grains of mercurial sublimate to prevent mould. In prescription No. 1, the latter is avoided by using vinegar.

No.3 Jahn's Black Ink. Two parts ground logwood, 12 parts Bablah, (an oriental gum containing tannin, and derived from acacias,) 200 parts water. Boil down to 100 parts, alter through linen, and add 1 part powdered gum-arabic, 1 part sugar, and 3 parts copperas. To prevent mould, add a solution of 1-100th part of mercurial sublimate in 1 part water.

No.4 Lewis's Black Writing-Fluid. One part powdered copperas, 1 part logwood, 3 parts crushed gall-buts, 1 part gum-arabic, 100 parts white wine or vinegar.

No.5 Reid's Prescription. Eight parts crushed gall-nuts, 2 parts copperas, 2 parts gum-arabic, 70 parts of water. (This ink must become mouldy. - Ed.)

No.6 Reban Court's Writing-Fluid. Boil 8 parts powdered Aleppo gall-nuts, and 4 parts thin shavings of logwood, for one hour, in 200 parts of water until reduced to 100 parts. Filter and add 4 parts copperas, 3 parts gum-arabic, 1 part blue vitriol, (cupric sulphate,) and 1 part white sugar; let the mixture stand one day and preserve in closed bottles.

In these six prescriptations, of German, English, and French origin, copperas or sulphate of iron is the chief ingredient. Lately, however, a substitute has been found in the chromate compound, which is the chief ingredient in the following prescription:
No.7 Runge's Writing-Fluid for Steel Pens consists of 1000 parts of extract of logwood, made by boiling down 155 parts of logwood in 2000 parts of water; filter and add 1 part of yellow chromate of potash. This ink is of a very bluish tint when first used; but unlike those made from iron, it leaves no deposit when exposed to the air. To prevent mould, add a few drops of a solution of bi-chloride of mercury. We think it likely that the inks inquired after by our correspondent are similar or even identical with this prescription.

[105] Writing-Ink Powder. [Q:] - I have heard of a powder of which only half an ounce is sufficient to make with water a whole pint of good black writing-ink. Is there any such powder? and if so, can you oblige a subsciber by mentioning where it can be had, or how it is made? [A:] - There is such a thing. It is a German invention, called Platzer's ink-powder. We have also seen the same or a similar preparation, manufactured in New-England, but by whom we have forgotten. However, our correspondent can easily make it for himself from the following recipe: Take 100 parts dry extract of logwood, well mixed and ground with one part fine bi-chromate of potash; that's all. Half an ounce is sufficient to change a whole pint of water into beautiful black ink.

[108] Quantity of Paint Required. [Q:] - What proportion of oil, turpentine, and lead do painters allow per square on new work, for first and second coats separately? - L. H. C. of Athens, Ga. [A:] - Painters estimate on new work, about one pound of paint per aquare yard for the first coat, and nearly half a pound for the secon coat; the proportion of paint is about half white lead and half oil or turpentine; however, there is often some variation from this estimate allowed, depending on the kind of wood to be painted, the purity of the white lead employed, and the quality of the work desired to be produced; good work requires an additional third coat of also half a pound per square yard.

Ei kommentteja :