EXPERIMENrS ON JLIGHT. 215 



The folar fpedrum therefore is accompanied by two invifi- vlfible ray be- 



ble rays, one on the red fi.ie, which favours oxicjenation, and y"'"^ "^If '■^l^* 

 , . . . 1 hus there 13 aJi 



the other on ilie violet fide, which favours diioxigenation. invifible ray 



The vifible and coloured rays partake more or lefs of the pro- P'»'"?t'"g'o^'- 



.- rj.\ r ■ r,, ■ , , 1 ■ r genation, and 



perties ot tnele invihbie principles, whence we ought to inter, another the con- 

 that all the coloured ravs contain more or lefs of thefe princi- ^'^^^y> 



J •' and the vifible 



P * and coloured 



Thefe experiments fucoeed very well with phofphorus. On "ys partake 

 Jetting the invifible ray adjoining the red fall on it, it immedi- Se'^p°opertie° of 

 ately emits white fumes: but if the invifible ray adjoining the both. 

 violet be thrown on the phofphorus in a ftate of oxigenation, it ^^i]^^fj^lyj'^ 

 IS inRantiy estingu'thed, with the fame rapidity as a frog is likewife kindles 



convulfed in galvanic experiments. ' phoiphorus; 



^ . ^ ' while that on the 



1 heie experiments readily accord with fome others made by violet Hde ex- 

 the fame gentleman. He kept one of his eyes for fome mi- tinguiflies it in- 

 nutes in conta6t with (he negative condudor of Volta's pile, One of the eyes, 

 and after this operation all objedls appeared red to him: but being kept fome 

 r. 1 • 1 •, • r^ • I ,1 r,- ) n 1 niinutes in con- 



auer having kept it inconlad with the politive conductor, he j^^ ^j^j^ the 



faw every thing blue. It is to be obferved here, that the re- negative conduc- 



tina and optic nerve, when the external part of the eye is p°[g° ^lj°^[^^g^^j 



brought into the negative ftate, become pofitive, and vice verfa; appeared red tq 



becaufe the eye is filled with a fluid, in which the fame dif- '^5 jncontaft 



•^ . with thepofitiv^ 



tnbution or eledricity muft take place, as in water and other blue. 



fluids. It is in the pofitive ftate therefore, that the optic nerve I" the former 



II 1 • ^ r 11 1-1 ■ n cafe the optic 



perceives all objects ot a red colour; and m the negative ttate nerve is in the 



they appear violet. The chemical aflion of pofitive eledri- pofit've ftate j 



city likewife is the fame as that of red light; that is, they both necrative. * 



favour oxigenation. Negative elecStricity and the violet ray The chemical 



polTefs the fame analogy, both promoting difoxigenation : as t;ve°e'learic^tv' 



the experiments with the galvanic pile have futliciently fliown. likewife tavouis 



If I might be allowed to add any obfervation to thefe im- o^_|genation, like 

 ° . ' \ red light ; and 



portant difcoveries, I would mention one of the moft com- negative, the 

 monly known fa6ls ; that the oppofite eleftricities, when ^""^''^''y* 

 united, produce light ; which feems to. deinonftrate fynfheti- tridties too pro- 

 cally, what the preceding experiments have fliewn by analyfis. «^"ce light by 



This account was read to the philoniathic fijciety feveral ^\^^^\^ {ttmi, to 

 months ago, fince which time Mr. Ritter has publiilied fome prove fyntheti- 

 new obfervations that deferve notice. He has found, wiih all ^" Vith the^"' 

 the prifms he ufed, that the folar rays give two coloured fpec- chemical rays. 

 trums, which fpread in proportion to their diftance from t^g Mr- R. ha^ fince 

 jprifm, fo that at a certain diftance one nearly covers the other, the prifm affords 

 ■ ' T\i^ ^wo fpeftrumsj 



