s 
¥799.] 
Experiments on Colours—Circulation of Stock, 
313 
EXPERIMENT XXXV. 
Red Violet 192 = Orange 27-+4+Red 45+ Violet 804 Indigo 40 
; Green 168 — Blue 60+ Green 60+ Yellow 48 

360 White. 
See ‘Table F 6. 
EXPERIMENT XXXVI; 
Violet Indigo 225 = Red 45+ Violet 80+4 Indigo 404 Blue 60 
Yellow 135 — Green 60+ Yellow 484 Orange 27 

360 White. 
Tt may perhaps be found that this is 
the moft harmonious combination of co- 
lours poflible;-and that which perfons of 
tafte would adopt with the happiett effect 
in their drefs, in the colouring of their 
apartments, or in any fubject which co- 
lours are employed to embellith. 
In part 2d, of the 76th vol. of the Phi- 
lofophical Tranfactions, for the year 
1786, a very interefting and ingenious 
memoir is publifhed, containing various 
experiments by Dr. Robert Darwin, on 
the ocular fpectra of light and colours. 
In this memoir it is obferved, that if a 
piece of coloured filk, about an inch in 
diameter, be placed on a fheet of white 
paper, about half a yard from the eye, 
and it be looked upon fteadily for a mi- 
nute, and the eye be then removed to 
another part of the white paper, a fpectrum 
will be feen of the form of the filk ; but of 
a colour oppoilite to it, viz. — 
Red filk produces a blue green fpeCtrum, 
Orange . . . anindigo blue. 
Yellow . . . a violet indigo. 
Green «©. . a red violet. 
Blue. . - . amorange red. 
Indigo . « » a yellow orange. 
Violet . . 4 a green yellow. 
Now thefe f{pectra are precifely of the 
colour which, combined with that colour 
which produced them, compofe white, 
agreeable to the Experiments from F x and: 
‘fe 
In the Philofophical Tranfaétions for 
the year 1794, Part 1ft, page 107, there 
is an account of fome very interefting 
experiments on the effeéts of light trant- 
mitted through coloured glafs, by Sir 
Benjamin Thompion, Count Rumford: 
é.g. provide two candles, and let the 
light proceeding from one, pafs through a 
coloured glafs; let the other candle be fo 
much farther removed from an obje& in- 
tercepting the light of both, that the two 
fhadows of that objet produced by the 
_candles be equally firong; or in other 
words, let the light tran{mitted through 
the glafs, when it falls on the object, 
whoie thadow is to be received, be equally 
See Table F 7. 
intenfe with the light proceeding imme 
diately from the more diftant candle; one 
of thefe fhadows will be of the colour of 
the glafs, the other will be the oppofite 
colour, or that colour which combined 
with the tran{mitted colour would pro- 
duce white. 
The two fhadows produced by two 
candies, one tran{mitting the light through 
a coloured glafs, the light of the other 
falling immediately on the objeét will be, 
Ifthe glafs be Violet —-Violet and green yellow 
Indigo —Indigo and yellow orange 
Blue——-Blue and orange red 
Green —Green and red violet 
Yellow— Yellow and violet indigo 
Orange—Orange and indigo blue 
Red Red and blue green. 
Thefe Experiments, which are eafily 
made, and very amufing, coincide with 
thofe from F 1 to F 7, No. 30 to 36, and 
with the Experiments on the Ocular Spec- 
tra, made by Dr. Robert Darwin, and re- 
ferred to in Dr. Darwin’s Zoonomia; 2 
work which may be confidered as one of 
the firft produCtions of the human mind. 
Fig. 3. Isa table fhewing the numeral! 
relation which the feveral colours bear to 
each other, beginning with any colour in 
the prifmatic fpectrum. 
Birmingham. S. GALTON, Jun. 
oe 
To the Editor of the Monthly 
SIR, : 
UPPOSING the National Debt to be 
S equal to four hundred millions (or 
more of 3 per cent. Annuities, of the va~ 
lue of 50 per cent. that is, two hundred 
millions fterling ; fifty millicns, or more 
if it can be employed, of this property, 
may be put into circulation, in the follow- 
ing manner. Let any ftockholder, who 
would with to circulate fome part of his 
ftock, without felling it, transfer a cer- 
tain quantity of it, {uppofe twenty thou- 
fand pounds 3 per cents. to the Governors 
and Direétors of the Bank, who are then 
to deliver to bim fifty certificates, or 
notes of transfer; each of them to be 
marked as of the value of sool. or a 
greater-quantity in number, and of lefs 
value 

Magazine. 
