Part 5 (2/2)

A mixture of sulphur assists the accension of these substances, and unpowder, in the explosion of which isticated air is suddenly produced, and expanded by the heat The application of this force, both to useful and destructive purposes, is well known If, instead of nitre, a salt isticated marine acid be made use of, the explosion is more easily produced, and is much more violent Friction will do this as well as heat

Nitre also enters into the composition of _pulvis fulminans_, viz three parts nitre, two of dry alkali, and one of sulphur This composition melts, and yields a blue flame, before it explodes

By means of the affinity of the nitrous acid to _oil_, another substance containing phlogiston, it is capable of producing not only a great heat, but even a sudden flame, especially when mixed with a little vitriolic acid

Nitrous acid dissolves all old and platina, and in the solution nitrous air is produced

The particular kinds of saline substances formed by the union of the nitrous acid with the several metals and earths may be seen in tables constructed for the purpose They are all deliquescent

LECTURE XIII

_Of the Vitriolic Acid_

The vitriolic acid, so called because it was originally procured froenerally procured fro with it in the act of burning

That dephlogisticated air is essential to this acid is evident from the decomposition of it; for if the vapour of it be reat quantity of dephlogisticated air is procured

This acid has a strong affinity to water, hich it unites with reater concentration, or of being made specifically heavier, than any other acid When pure, it is entirely free fro free froiston, which is inseparable from the nitrous or e the nitrous, or marine, or any other acid, from their earthy or est of all the acids

By means of the superior affinity of the vitriolic acid to earths, and especially to _terra ponderosa_, the smallest quantity of it in water may be discovered by a solution of this earth in the marine acid In this acid the terra ponderosa is held in perfect solution; but with the vitriolic acid it forms a substance that is insoluble in water, and therefore it instantly appears in the for affinity which this acid has ater, _pyrophorus_, consisting of a iston, takes fire spontaneously on exposure to the air

It is coar, or of two parts alum, one of salt of tartar, and one of charcoal They must be heated till they have for some time emitted a vapour that burns with a blue flame

The saline substances produced by the union of this acid with the several earths and metals, are best exhibited in tables constructed for the purpose When united to three of the metals, viz iron, copper, and zinc, they are called _vitriols_, green, blue, and white And all the substances which this acid unites with crystallize, and do not deliquesce

This acid unites with oil, and thephlogiston is heated in the vitriolic acid, another species of the acid, called _sulphureous_, is fornated with vitriolic acid air It ed from its base by most of the others

_Of the Marine Acid_

The marine acid is procured from common salt by the vitriolic acid, which unites with its base, the fossil alkali

This acid is generally of a straw-colour; but this is owing to an ination with some earthy matter, most of which it readily dissolves, especially the metallic ones It is less capable of concentration than the vitriolic or nitrous acids, perhaps froiston with it No heat can extract froh this is denominated a weaker acid than the nitrous, yet it will take silver, lead, or mercury, from their union with the nitrous acid

Upon this principle, a solution of these metals in the nitrous acid will readily discover whether any water contains thewith thewith it, if it be silver, a _luna cornea_; which being a substance insoluble in water, discovers itself by a cloudy appearance

The union of the marine acid with earths forms salts that easily deliquesce, but with the metals such as are capable of crystallization; and so also is that formed by the union of this acid to terra ponderosa

Neither this acid nor the nitrous will dissolve gold or platina; but a ia_, will do it