90 
series of comparisons now before me, in- 
cluding many of the brilliant colors of silk 
ribbons recently so fashionable, I have had 
to reduce the intensity of the color to be 
reproduced, in only two out of sixty cases. 
This comparison was made by means of 
Maxwell dises made from the Bradley edu- 
cational papers. For all practical purposes 
some form of paper or card board dise 
seems more convenient and proves quite 
satisfactory, as the above statement shows 
While it is possible to get somewhat more 
of brillianey in silk than in pigment-coy- 
ered papers, I have not found the increased 
brillianey of sufficient value to compensate 
for the difficulty of making silk-covered 
discs that can be conveniently operated. 
For educational purposes it seems to me 
of first importance that the child (and 
many adults are children in this regard) 
should start out with some clear and cor- 
rect idea of a few pure spectrum colors. It 
does not matter essentially just how many 
of these colors he is taught, only that he 
gets a definite conception of those of which 
he learns. The reason for taking six for 
this series of standards was that I found 
that it was very difficult to get any practi- 
cal scheme of color teaching based on a 
less number of standards. The mixing of 
two standards by means of the color wheel 
always reduces the strength of the result- 
ing color. For example, the mixing of 
red and yellow on the wheel will produce 
orange, but it will not be as strong an 
orange as that of the standard paper. It 
willbea broken orange. Using the nomen- 
clature adopted in my former articles (Scr- 
ENCE, February 26, ’92,and June 9,’93) we 
have the result represented as follows: R 
82 Y 18 gives the same effect as O55 W 2 
N 43. This can be best tested by using 
two sizes of discs. The larger should 
be compounded of red and yellow in the 
proportions just given and the smaller of 
orange, white and black as indicated. In 
SCIENCE. 
(N.S. Voz. VI. No. 133. 
this way the result is very satisfactory in 
fairly strong and pure diffused sunlight. 
The same principle will apply to all the 
colors of the spectrum. But the extent to 
which the effect of a broken color is pro- 
duced will be increased, as the colors differ 
more widely in luminosity, or are more 
widely separated in the solar spectrum. 
Hence asmaller number of standards makes 
the practical use of the standards more dif- 
ficult in the pupil’s study of the colors by 
the use of the Maxwell dises. If we take a 
larger number of colors than six it becomes 
more difficult to designate them clearly in 
the solar spectrum, and the system becomes. 
more complex. As there is quite general 
agreement that indigo shall not be used as 
a name for a spectrum color, the most nat- 
ural and far the most convenient terms are 
those used in the scheme already referred 
to. When the pupil becomes familiar with 
these standard colors he is prepared to 
make very rapid progress in color study. 
The combination of these standards will 
give a ready appreciation of the nature of 
the purer color in objects about him and 
prepare the way for the analysis of colors, 
first those of a pure tone and afterwards of 
broken colors. The next stage would be 
the teaching of color harmonies. This most 
difficult part of the work becomes relatively 
easy by means of educational papers con- 
structed on so simple a plan as this. It is 
surprising to see what results are obtained 
in the schools where this system has been 
followed. 
It seems not inappropriate in this con- 
nection to call attention to an attempt to 
apply the principles upon which I have 
worked with a somewhat different set of 
standards from those I have used under 
the article ‘spectrum’ in the Standard Dic- 
tionary. In the first place there is no pure 
red used in the system, that called red be- 
ing an orange red, as represented by the 
pigment vermilion. Nor is there any violet 
