>AOr£ATIES OF NITRIC ACID.

2S5

NITRIC ACID.

PART LXXXIII.

PROPERTIES OF NITRIC ACID.

IN ITRIC acid is liquid, colourless, and transparent, possessingin a very eminent degree all the properties of acids. It tingesthe skin yellow, which does not disappear till the epidermiswears off. It has a strong affinity for water, and has never yetbeen found in nature except in combination. It produces heatwhen added to water. When concentrated it exhales white acridfumes on being exposed to the air, which are nitric acid in agazeous state. When poured on oils, charcoal, &c. it sets themon fire. (See vol. I. p. 19.) It causes the sulphureous andphosphorous acids to pass to the state of sulphuric and phospho-ric acids, by yielding to them part of its oxigen. It is capableof oxidating all the metals e.xcept gold, platina, titanium, andtantalite.

METHODS OF OBTAINING NITRIC ACID.

Nitric acid cannot be produced in any considerable quantity,by the direct combination of its principles, without a great dealof labour; though that it may be so formed for the sake of expe-riment has been shown, vol. I. p. 211 .