>O.\-OXYGENAT1ON OF PHOSPHORUS. 



of these alone would be incompetent to produce this result And in the case of gas, 

 such as oxygen, being evolved from spring water, we are to refer the change to the 

 ready decomposition of capillary compounds, compounds essentially distinct from chem- 

 ical, and which can suffer decomposition by the force of capillary action. The colo- 

 rific and the chemical rays have no influence in this latter case. 



439. NOX-OXYGEXATIOX OF PHOSPHORUS. It is stated in the books that Ritter, in 

 making observations on the slow combustion of phosphorus at common temperatures, 

 found that it emitted white fumes in the invisible red ray of the solar spectrum, but in 

 the invisible violet, phosphorus in a state of oxygenation was instantly extinguished. 

 As a similar action is alleged to take place when the sun's rays shine on ignited car- 

 bon, it becomes desirable to understand the mode of action : the original experiment of 

 Ritter was therefore repeated, with a view to ascertain its accuracy. A cylinder of 

 phosphorus, a b {fig. 62), an inch long, and about one sixth of an inch in diameter, 

 was shielded from the action of aerial currents by a glass jar. In front of the jar an 

 equiangular prism of flint glass was placed, so that the rays of a decomposed beam of 

 light coming in through the shutter, c d, could successively be thrown on the phosphorus, 

 which was placed horizontally in the jar ; the beam of light also came nearly horizon- 

 tally into the room, reflected by the arrangement already described. Situated thus, 

 by turning the prism on its axis, any ray could be made to cover the phosphorus: the 

 temperature in the shade being 72 Fahr., a fine sheet of metaphosphoric acid, mingled 

 with vapour of phosphorus, so thin as to be almost imperceptible, except in certain po- 

 sitions, was observed to be rising from the cylinder; sometimes it would form a fine 

 cloud, which hung for a moment on the phosphorus, and then rose gracefully in curled 

 wreaths. The extreme mobility of this cloud was remarkable : even the warmth of the 

 observer, by causing currents within the jar, would affect it ; if the hand approached, as 

 at A (Jig. 63), the phosphoric vapour came to the side of the vessel, as it were to meet 

 it. and then rebounded and circulated along the top of the jar. The size, position, 

 and shape of this cloud, when enveloped in the red light of the prism, were deliber- 

 ately marked; its motions were merely more capricious than when in the shade. And 

 now, by turning the prism, the extreme violet ray was brought upon it, but neither 

 did its motion, nor magnitude, nor figure appear in any wise changed. 



440. The impression conveyed by Ritter's experiment is, that the chemical rays 

 possess the faculty of hindering oxygenation. The negative conclusion here arrived 

 at might be due to local circumstances, and be referred to the action of the prism, as 

 to its composition, to the state of the atmosphere, &c.; but no better success attended 

 a variety of trials made on different days, and with prisms of crown glass, turpentine, 

 and water. Trial was therefore made of absorbing media, a beam of light being made 

 to pass at one time through a solution of sulphate of copper and ammonia, and at an- 

 other through bichromate of potassa. but the condition of the phosphorescent cloud 

 was found to be too rough an estimate of the real action. A cylinder of glass (A B, 

 Jig. 64), -75 inch in diameter and 3 inches long, was therefore fitted at its upper end 

 with a stopcock, a; its lower extremity was closed air-tight with a cork, through which 

 an inverted siphon, b b, passed, each of its limbs being four inches long, and the bore 



