United States or Saint Barthélemy ? Vote for the TOP Country of the Week !
According to the same law, a certain weight of soda would always require a certain specific equivalent weight of an acid, say hydrochloric acid, to neutralise its alkaline or basic properties, producing a salt. The specific gravities of acids and alkalis in solution are made use of in works, etc., as a means of ascertaining their strengths and commercial values.
So much as this, that only such unstable salts as I have just described, which decompose and yield precipitates by the action on them of alkalis, heat, the textile fibres themselves, or other agencies, are suitable to act as true mordants. Hence, generally, the sources or root substances of the best and most efficient mordants are the metals of high specific appetite or valency.
If some wool be placed in a dry glass tube, and heated strongly so as to cause destructive distillation, products containing much carbonate of ammonium are given off. The ammonia is easily detected by its smell of hartshorn and the blue colour produced on a piece of reddened litmus paper, the latter being a general test to distinguish alkalis, like ammonia, soda, and potash, from acids.
Causticity and fluidity have long since been excluded from the characteristics of the class, by the inclusion of silica and many other substances in it; and the formation of neutral bodies by combination with alkalis, together with such electro-chemical peculiarities as this is supposed to imply, are now the only differentiæ which form the fixed connotation of the word Acid, as a term of chemical science.
You will please to observe that I reckon both those capital discoveries of Davy the fruit of inquiry, and not at all of chance for, as to the lamp, it is plain; and as to the metals, if you look at the inquiries that immediately preceded, you will see he was thereby led to the alkalis. Indeed, I well remember saying, when I read them, "He will analyse lime and barytes."
Another extremely sensitive indicator is the coal-tar dyestuff known as "Congo red"; the colour changes produced by it are exactly the inverse of those produced in the case of litmus, that is, it gives a blue colour with acids and a red colour with alkalis.
Dilute caustic alkalis, if sufficiently dilute, will dissolve off the sericin and leave the inner fibre of fibroïn; but they are not so good for ungumming silk as soap solutions are, as the fibre after treatment with them is deficient in whiteness and brilliancy.
He subjected bodies of the most varied qualities to the action of his magnet: mineral salts, acids, alkalis, ethers, alcohols, aqueous solutions, glass, phosphorus, resins, oils, essences, vegetable and animal tissues, and found them all amenable to magnetic influence. No known solid or liquid proved insensible to the magnetic power when developed in sufficient strength.
Baron Japhet applied the nervous fibres of his tongue to the skin; he had skill in thus detecting salts, acids, alkalis, and gases. After several experiments, he remarked: "No taste whatever! Come, we will give it a little fluoric acid to drink." Subjected to the influence of this ready solvent of animal tissue, the skin underwent no change whatsoever.
Assyrian glass was either transparent or stained with a single uniform color. It was composed, in the usual way, by a mixture of sand or silex with alkalis, and, like the Egyptian, appears to have been first rudely fashioned into shape by the blowpipe. It was then more carefully shaped, and, where necessary, hollowed out by a turning machine, the Marks of which are sometimes still visible.
Word Of The Day