Scientific American 41, 20.6.1857
Washing has for its object not only the removal from our clothing of accidental dirt, but aLso to carry away certain ammoniacal salts, the products of perspiration, which are absorbed from the body by all the clothes that we wear, especially those nearest to the skin. A change of under garment is essential to health on this very account, and the art of washing is more useful in removing the hardened perspiration from the cloth to which it clings most pertinaciously, like the matter of contagion) than in removing the superfluous dirt which merely offend the eye. Until recently, the laundress's first operation was to prepare "a ley" of potash, which she did by putting wood ashes into a tub having a perforated bottom. The tub was then filled with water, which, trickling through, dissolved in its course the potash contained in all wood ashes. This process is still extant in some parts of the country, especially where wood is used for fuel.
The starting process of washing now is to prepare a ley of soda. Hard water requires more soda than soft; and, when rain water can be procured, alkali may be dispensed with entirely. The utility of soda or of potash in washing arises from the power these alkalies possess of uniting with grease of all kinds, forming a soap; and to disunite the ammonia of the perspiration from the clothes, thus purifying the fabric and rendering it capable of the like absorption when again worn. This important action has hitherto been unnoticed. Now, although we admit their great utility, we particuarly caution all parties not to use too much of these powerful alkalies, because cotton fabrics are partially dissolved by a strong hot soda, potash, or lime ley. It is to this cause that the "bad color" may be attributed, which the house-wife now and then justly complains of in the linen. When the outer coatings of the filament of the fabric are thus acted upon, they are quickly influenced by the air, and become, of a yellow tint.
There is another cause of "bad color," and that is an insufficient supply of water, or washing too many things in the same liquor. This gives rather a gray tint. The yellow color is, however, the great thing to guard against, as this partakes of a permanent evil; and we mention it in particular, because there are strong washing fluids sold containing lime and soda. In nine laundries out of ten, too much soda is already used; we need not, therefore, desire to increase the evil.
Many laundresses, when they hear complaints of the color of the articles they send home, will make their alkaline ley a little stronger next washing-day, and thus unwittingly increase the evil. It judicious use of soda or pearl ash is highly beneficial, and a saving of labor; but, if in excess, is very injurious.
The strong lixivium, recently recommended for washing linen, has long been known to those who require to cleanse metals front impurities on the surface only. Printers, for instance, may use it with safety to cleanse the face of their type from the unctuous ink used in printing, because the ley is not strong enough to affect the metal. The very low priced soups are by no means the cheapest in use; and they also impart an unpleasant odor to the linen, which cannot he got rid of.
The use of "blue" in rinse water is too well known to need comment further than to our purpose. The ordinary blue is a compound of Prussian blue and starch. The color that it gives merely covers the yellow tint of the goods, without doing more. We would suggest the use of pure indigo instead of the common blue. This advice is founded upon practice as well as theory. Indigo, in this operation, is without any bad action on the fabric. Persons employed in the "indigo department" of the docks have the whitest linen of all people in London.
- S. Piesse.
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