254 Mr. Brougham's Experiments and Observations on 
through are those from red and orange objects, and last from 
blue and violet. Now it is evident that transparency in ge- 
neral, and this particular fact, are explicable by what was be- 
fore laid down. It was found by Newton, that a body trans- 
mits the light incident on it more or less, according to the 
continuity of its particles, and that a strong reflection takes 
place on the confines of a vacuum.* How does this happen ? 
The initial velocity of light is sufficient to carry it through 
the first surface or set of particles, but it is so much dimi- 
nished, that it is reflected by the repulsive power of the back- 
side of these particles, unless there be others behind at a cer- 
tain distance, namely, that at which inflection or attraction 
acts, that is, apparent contact ; this attraction renews the im- 
petus of light, and transmits it to another set, and so on. 
Now this action being strongest on the largest and red par- 
ticles, and weakest on the blue and violet, if the continuity be 
diminished, the former will be transmitted, and not the latter; 
which is conformable to the experiment just now mentioned. 
3. The doctrine of flexibility furnishes an easy and satisfac- 
tory explanation of the different colours which are assumed 
by flame. Whether we suppose the light to come from the 
burning body, or the oxygenous gaz, the largest or red par- 
ticles have the strongest attraction for bodies, the violet the 
weakest ; when therefore the gaz and the body combine, the 
precipitation of light must be in the reverse order of the affi- 
nity between the particles of light and those of the bodies. If 
then the combination take place slowly, the violet and blue 
particles will be first emitted, and last of all the red ; and this 
is consistent with fact ; for any inflammable body whatever, 
* Optics, Bock II. PartHI. Prop. 3. 
