379190r
[Commentary:
This page is part of Harriot's
experiments on refractive colours. A summary of experimental apparatus and the raw observational data that Harriot obtained over four days in April, 1605, observing the coloured fringes on a card viewed through a glass triangular prism and a water-filled triangular prism. In the subsequent pages (now very disordered in the manuscript volume), Harriot will use the data recorded here to obtain a range of 'cardinal rays' for the two substances; or, in effect, a range of refractive indices responsible for the production of the spectrum of colours. ]
observations of colours. Aprill 8. 9. 10. 11.
bis observata: id est
duobus diversis diebus. tribus. 4or.
[Translation: Observed twice. That is, on two (three, four) separate days. ]
[Translation: Observed twice. That is, on two (three, four) separate days. ]
Angulus vitreus: 58° 0â²
Angulus incidentiæ: 51° 0â². distantia puncti ab angulo: inch.
Superficiei vitri oculo proximae distantia a charta — 6 feete — 12 feete
flavedo a termino chartae — 1 ynches — 2 inches
rubedo a termino chartae — ynch — 1 inch.
quasi. Termini non ita perfecte percipiuntur.
centrum perfectis fuit in perpendiculari ad chartam.
oculus a vitro 8 ynches.
[Translation: Angle of the glass:
Angle of incidence:
distance of point from the apex
Distance closest to the eye of the surface of the glass to the card:
Yellow, from the edge of the card:
Red, from the edge of the card:
Approximately. The edges were not so clearly perceived.
The centre was perfectly in the perpendicular to the card.
Eye from glass ]
Angulus incidentiæ: 51° 0â². distantia puncti ab angulo: inch.
Superficiei vitri oculo proximae distantia a charta — 6 feete — 12 feete
flavedo a termino chartae — 1 ynches — 2 inches
rubedo a termino chartae — ynch — 1 inch.
quasi. Termini non ita perfecte percipiuntur.
centrum perfectis fuit in perpendiculari ad chartam.
oculus a vitro 8 ynches.
[Translation: Angle of the glass:
Angle of incidence:
distance of point from the apex
Distance closest to the eye of the surface of the glass to the card:
Yellow, from the edge of the card:
Red, from the edge of the card:
Approximately. The edges were not so clearly perceived.
The centre was perfectly in the perpendicular to the card.
Eye from glass ]
I observed with the angle
of 60° of glasse, & sal gemmæ
& found them all one.
of 60° of glasse, & sal gemmæ
& found them all one.
Angulus aqueus: 60° 0â²
Angulus incidentiæ: 43°
Distantia: 6 feete
flavedo a termino chartæ: ynches
rubedo a termino chartæ: ynches
[Translation: Angle of water:
Angle of incidence:
Distance:
Yellow from edge of card:
Red from edge of card:
]
Angulus incidentiæ: 43°
Distantia: 6 feete
flavedo a termino chartæ: ynches
rubedo a termino chartæ: ynches
[Translation: Angle of water:
Angle of incidence:
Distance:
Yellow from edge of card:
Red from edge of card:
]
Of the same prisma of glasse with angles and distances as below.
At the angle of incidence 27° 0â²
this prisma I found
had not three angles
equall to two right angles,
wanting 1° 30â², & the sides not
playne. It was found not pira-
midall. The observations
therefore not to be trusted.
this prisma I found
had not three angles
equall to two right angles,
wanting 1° 30â², & the sides not
playne. It was found not pira-
midall. The observations
therefore not to be trusted.
The red is as big upon the or as large
from the end of the charta as the yellow
before. That is 1 ynches
from the end of the charta as the yellow
before. That is 1 ynches
The yellow as large agayne, that is 2 ynches,
and the image of the charta in appearance of much
less angle then in [¿]reali[?], more then half.
and the image of the charta in appearance of much
less angle then in [¿]reali[?], more then half.
At the angle of incidence of 67° 0â²: The yellow from the ende is ynch or there aboute.
The red aboute half that or a litle
The red aboute half that or a litle
The imago & by coniecture double the
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