494 * PHILOSOPHICAL TRANSACTIONS. [aNNO 1 788. 



begin to act on each other adds to them a little salt of tartar, will find volatile 

 alkali to be produced. Nitrous acid, or cupreous nitre, mixed with iron filings, 

 sulphur, and a little water, and kept in a close vessel for some hours, yields a 

 smell of volatile alkali; and if a piece of paper, stained with a vegetable blue 

 substance, be thrown into the vessel, it will soon be turned to a green colour. 

 In each of these experiments the nitrous acid and the water are decomposed. 

 Dephlogisticated air from each of them combines with the metal, and their 

 other constituent parts, the phlogisticated air of the acid, and inflammable air 

 of the water, being disengaged at the same instant, unite and form volatile 

 alkali. Many other similar experiments might be mentioned; but these are 

 abundantly sufficient to prove, that if phlogisticated and light inflammable air be 

 presented to each other at the instant of their separation from solid or liquid 

 substances, and before their particles have receded from each other, they readily 

 combine and generate volatile alkali. 



That these two substances do not combine in their elastic state, seems to be 

 owing principally to the inflammable air. When these 2 airs combine, it seems 

 necessary that they part with a certain quantity of that fire to which they owe 

 their elasticity; and that, unless their attraction to each other exceed their 

 attraction to fire, they will not unite. Even when they are combined in the 

 form of volatile alkali, if heat be applied, they immediately recede from each 

 other, and the alkali is decomposed. When they are not in an aeriform state 

 their attraction to each other is greater, on account of the proximity of their 

 parts; it is then superior to their attraction to fire, and therefore they combine; 

 but when their particles have receded from each other, as in the aeriform state, 

 their attraction to each other is so diminished by the distance of their parts, that 

 their attraction to fire, which is uniform, prevails, and keeps them in a separate 

 state. The specific gravity of inflammable air being J 1 times less than that of 

 phlogisticated air the distance of its particles must be greater than the distance 

 of the particles of phlogisticated air, in the proportion of y/ 1 1 to 1 , if 

 the elementary particles of the 2 airs be of equal magnitude; and its effect, 

 on this account, in diminishing attraction, must be greater than that of 

 phlogisticated, in the proportion of those numbers, or more probably as the 

 squares. 



Into a cylindrical glass tube, filled with, and inverted in, quicksilver. Dr. A. 

 introduced some phlogisticated air, and afterwards some iron filings moistened 

 with distilled water. By this arrangement light inflammable air, which is given 

 out from water in contact with iron filings, meeting with phlogisticated air at 

 the instant of its extrication, combines with it, and forms volatile alkali. In 

 order to detect the minute quantities of volatile alkali, which were thus generated, 

 he fixed to the inside of the glass tube a small piece of paper, stained with the 

 rind of the blue raddish. The vegetable blue was in 24 hours changed to a 



