Isaac Newton to Henry Oldenburg

View transcription
                                been now said of white. And so the necessity of all colours to produce white 
might have appeared by y<sup>e<\sup> experiment pag 5097 where I say that if any 
colour at y<sup>e<\sup> Lens be intercepted y<sup>e<\sup> whiteness (wch is compounded of them all)
will be changed into (y<sup>e<\sup> result of) the other colours.
However, since there seems to have happened some misunderstanding between 
us, I shall indeavour to explain my self a little further in these things according to 
the following method.
<u>Definitions <\u>
1. I call that Light homogeneal, similar or uniform whose rays are equally 
refrangible.
2. And that heterogeneal whose rays are unequally refrangible.
Note. There are but three affections of light in w<sup>ch<\sup> I have observed its rays 
to differ viz: Refrangibility, Reflexibility & Colour, & those rays w<sup>ch<\sup> agree in
refrangibility agree also in the other two & therefore may well be defined homo-
general: especially since men usually call those things homogeneal w<sup>ch<\sup> are so 
in all qualities that come under their knowledge, though in other qualities that their 
knowledg extends not to there may possibly be some heterogeneity 
3. Those Colours I call simple or homogeneal, which are exhibited by homo-
geneal light.
4. And those compound or heterogeneal w<sup>ch<\sup> are exhibited by heterogeneal light.
5. Different colours I call not only the more eminent species, red, yellow, green, blew 
purple, but all other <s>gradations <\> the minutest gradations: much after y<sup>e<\sup> same manner that 
not onely the more eminent degrees in musick but all y<sup>e<\sup> least gradations are esteemed 
different sounds.
<u>Propositions <\u>
1. The sun’s light consists of rays differing by indefinite degrees of refrangi-
bility.
2. Rays w<sup>ch<\sup> differ in refrangibility, when parted from one another do proportionally 
differ in the colours w<sup>ch<\sup> they exhibit. These two propositions are matter of fact.
3. There are as many simple or homogeneal colours as degrees of refrangibility.
For to every degree of refrangibility belongs a different colour by Prop: 2. And 
that colour is simple by <u>Def.:<\u>1, & 3.
4. Whiteness <s>such as is <\s> in all respects like that of the Sun’s immediate light & of all y<sup>e<\sup> usuall 
objects of o<sup>r<\sup> senses cannot be compounded of two simple colours alone. For
such a composition must be made by rays that have only two degrees of refran 
gibility by <u>Def<\u>. 1 & 3; & therefore it cannot be like that of the same light 
<u>Prop<\u>. 1; Nor for y<sup>e<\sup> same reason like that of ordinary white objects.
5. Whiteness in all respects like that of the Sun’s immediate light <s>may <\s> cannot be 
compounded of simple colours, <s>there are requisite <\s> without an indefinite variety of them. For in
such a composition there are requisite rays indued w<sup>th<\sup> all y<sup>e<\sup> indefinite degrees of 
refrangibility by <u>Prop<\u>. 1. And these infer as many simple colours, by <u>Def<\u>. 1, & 3. &
<u>Prop<\u>. 2 & 3
To make these a little plainer, I have added also the Propositions that 
6. The rays of light do not act on one another in passing through the same medium. This appears by several passages in y<sup>e<\sup> <u>Transactions pag<\u> 5097, 5098,
5100, & 5101, & is capable of further proof.
7. The rays of light suffer not any change of their qualities from refraction 
8. Nor afterwards from the adjacent quiet <u>Medium <\u>. These two Propositions 
are manifest de facto in homogeneal light, whose colour & refrangibility is not at all
                            
Please login to transcribe

Manuscript details

Author
Isaac Newton
Reference
EL/N1/47
Series
EL
Date
1673
IIIF
Open IIIF manifest
(What's this?)
This is a link to the IIIF web URL for this item. You can drag and drop the IIIF image link into other compatible viewers

Cite as

Isaac Newton to Henry Oldenburg, 1673. From The Royal Society, EL/N1/47

Copy

Comments

Please login to comment