Part 284

LANTERN SLIDES: See Photography.

«LARD:»

«Detection of Cottonseed Oil in Lard.»—Make a 2 per cent solution of silver nitrate in distilled water, and acidify it by adding 1 per cent of nitrate acid, C. P. Into a test tube put a sample of the suspected lard and heat gently until it liquefies. Now add an equal quantity of the silver nitrate solution, agitate a little, and bring to a boil. Continue the boiling vigorously for about 8 minutes. If the lard remain clear and colorless, it may be accepted as pure. The presence of cottonseed oil or fat will make itself known by a coloration, varying from yellow, grayish green to brown, according to the amount present.

LATHE LUBRICANT: See Lubricants. {443}

LAUNDRY INKS: See Household Formulas.

«Laundry Preparations»

«BLUING COMPOUNDS:»

«Laundry Blue.»—The soluble blue of commerce, when properly made, dissolves freely in water, and solutions so made are put up as liquid laundry blue. The water employed in making the solution should be free from mineral substances, especially lime, or precipitation may occur. If rain water or distilled water and a good article of blue be used, a staple preparation ought apparently to result; but whether time alone affects the matter of solubility it is impossible to state. As it is essential that the solution should be a perfect one, it is best to filter it through several thicknesses of fine cotton cloth before bottling; or if made in large quantities this method may be modified by allowing it to stand some days to settle, when the top portion can be siphoned off for use, the bottom only requiring filtration.

This soluble blue is said to be potassium ferri-ferrocyanide, and is prepared by gradually adding to a boiling solution of potassium ferricyanide (red prussiate of potash) an equivalent quantity of hot solution of ferrous sulphate, boiling for 2 hours and washing the precipitate on a filter until the washings assume a dark-blue color; the moist precipitate can then at once be dissolved by the further addition of a sufficient quantity of water. About 64 parts of the iron salt are necessary to convert 100 parts of the potassium salt into the blue compound.

Leaf bluing for laundry use may be prepared by coating thick sized paper with soluble blue formed into a paste with a mixture of dextrin mucilage and glycerine. Dissolve a given quantity of dextrine in water enough to make a solution about as dense as ordinary syrup, add about as much glycerine as there was dextrine, rub the blue smooth with a sufficient quantity of this vehicle and coat the sheets with the paint. The amount of blue to be used will depend of course on the intended cost of the product, and the amount of glycerine will require adjustment so as to give a mixture which will not “smear” after the water has dried out and yet remain readily soluble.

Ultramarine is now very generally used as a laundry blue where the insoluble or “bag blue” is desired. It is mixed with glucose, or glucose and dextrine, and pressed into balls or cakes. When glucose alone is used, the product has a tendency, it is said, to become soft on keeping, which tendency may be counteracted by a proper proportion of dextrin. Bicarbonate of sodium is added as a “filler” to cheapen the product, the quantity used and the quality of the ultramarine employed being both regulated by the price at which the product is to sell.

The coal-tar or aniline blues are not offered to the general public as laundry blues, but laundry proprietors have them frequently brought under their notice, chiefly in the form of solutions, usually 1 to 1 1⁠/⁠2 per cent strong. These dyes are strong bluing materials, and, being in the form of solution, are not liable to speck the clothes. Naturally their properties depend upon the particular dye used; some are fast to acids and alkalies, others are fast to one but not to another; some will not stand ironing, while others again are not affected by the operation; generally they are not fast to light, but this is only of minor importance. The soluble, or cotton, blues are those most favored; these are made in a great variety of tints, varying from a reddish blue to a pure blue in hue, distinguished by such brands as 3R, 6B, etc. Occasionally the methyl violets are used, especially the blue tints. Blackley blue is very largely used for this purpose, being rather faster than the soluble blues. It may be mentioned that a 1 per cent solution of this dye is usually strong enough. Unless care is taken in dissolving these dyes they are apt to produce specks. The heat to which the pure blues are exposed in ironing the clothes causes some kinds to assume a purple tinge.

The cheapest aniline blue costs about three times as much as soluble blue, yet the tinctorial power of the aniline colors is so great that possibly they might be cheapened.

«Soluble Blue.»—I.—Dissolve 217 parts of prussiate of potash in 800 parts of hot water and bring the whole to 1,000 parts. Likewise dissolve 100 parts of ferric chloride in water and bring the solution also to 1,000 parts. To each of these solutions add 2,000 parts of cooking salt or Glauber’s salt solution saturated in the cold and mix well. The solutions thus prepared of prussiate of potash and ferric chloride are now mixed together with stirring. Allow to settle and remove by suction the clear liquid containing undecomposed ferrocyanide of {444} potassium and Glauber’s salt; this is kept and used for the next manufacture by boiling it down and allowing the salts to crystallize out. The percentage of ferrocyanide of potassium is estimated by analysis, and for the next production proportionally less is used, employing that obtained by concentration.

After siphoning off the solution the precipitate is washed with warm water, placed on a filter and washed out on the latter by pouring on cold water until the water running off commences to assume a strong blue color. The precipitate is then squeezed out and dried at a moderate heat (104° F.). The Paris blue thus obtained dissolves readily in water and can be extensively employed in a similar manner as indigo carmine.

II.—Make ordinary Prussian blue (that which has been purified by acids, chlorine, or the hypochlorites) into a thick paste with distilled or rain water, and add a saturated solution of oxalic acid sufficient to dissolve. If time be of no consequence, by leaving this solution exposed to the atmosphere, in the course of 60 days the blue will be entirely precipitated in soluble form. Wash with weak alcohol and dry at about 100° F. The resultant mass dissolves in pure water and remains in solution indefinitely. It gives a deep, brilliant blue, and is not injurious to the clothing or the hands of the washwoman.

The same result may be obtained by precipitating the soluble blue from its oxide solution by the addition of alcohol of 95 per cent, or with a concentrated solution of sodium sulphate. Pour off the mother liquid and wash with very dilute alcohol; or throw on a filter and wash with water until the latter begins to come off colored a deep blue.

«Liquid Laundry Blue.»—This may be prepared either with liquid Prussian blue or indigo carmine. Make a solution of gum dragon (gum tragacanth) by dissolving 1 to 2 ounces of the powdered gum in 1 gallon of cold water in which 1⁠/⁠2 ounce oxalic acid has been dissolved. The gum will take several days to dissolve, and will require frequent stirring and straining before use. To the strained portion add as much Prussian blue in fine powder as the liquid will dissolve without precipitating, and the compound is ready for use.

Instead of powdered Prussian blue, soluble Prussian blue may be used. This is made by dissolving solid Prussian blue in a solution of oxalic acid, but as the use of oxalic acid is to be deprecated for the use of laundresses, as it would set up blood poisoning should it get into any cuts in the flesh, it is best to prepare liquid blue by making a solution of yellow prussiate of potash (ferrocyanide of potassium) with water, and then by adding a sufficient quantity of chloride of iron to produce a blue, but not enough to be precipitated.

«Ball Blue.»—The ball sold for laundry use consists usually, if not always, of ultramarine. The balls are formed by compression, starch or some other excipient of like character being added to render the mass cohesive. Blocks of blue can, of course, be made by the same process. The manufacturers of ultramarine prepare balls and cubes of the pigment on a large scale, and it does not seem likely that there would be a sufficient margin of profit to justify the making of them in a small way from the powdered pigment. Careful experiments, however, would be necessary to determine this positively. Ultramarine is of many qualities, and it may be expected that the balls will vary also in the amount of “filling” according to the price at which they are to be sold.

Below is a “filled” formula:

Ultramarine 6 ounces Sodium carbonate 4 ounces Glucose 1 ounce Water, a sufficient quantity.

Make a thick paste, roll into sheets, and cut into tablets. The balls in bulk can be obtained only in large packages of the manufacturers, say barrels of 200 pounds; but put up in 1-pound boxes they can be bought in cases as small as 28 pounds.

«Laundry Blue Tablets.»—

Ultramarine 6 ounces Sodium carbonate 4 ounces Glucose 1 ounce Water, a sufficient quantity.

Make a thick paste, roll into sheets, and cut into tablets.

«Polishes or Glazes for Laundry Work.»—I.—To a mixture of 200 parts each of Japan wax and paraffine, add 100 parts of stearic acid, melt together, and cast in molds. If the heated smoothing iron be rubbed with this wax the iron will not merely get over the surface much more rapidly, but will leave a handsome polish.

«Laundry Gloss Dressing.»—