680 Analyses of Books. [November, 
more black, a deeper shade of all colours — in its extreme 
black.” 
In this parallelism of notes and colours we do not find the 
clearness which would be desirable. Red, yellow, and blue, if 
we understand Mr. Hughes aright, contain each all colours. We 
should like to see some experimental proof of this proposition. 
As far as research has gone, true red — the red of the spedtrum — 
is what might be called a chromatic element from which nothing 
but red can be eliminated, although it may be blended with other 
colours to form compound shades. As regards yellow and blue, 
which the author classes along with red as “ the three great 
apparent primaries,” their elementary or simple character is not 
generally recognised. Indeed Mr. Hughes refers to Clerk 
Maxwell’s proof that red and green in right proportions produce 
yellow. Violet the author likens to “ blue and all colours in- 
clining to black.” To our eye a true violet might rather seem 
blue inclining to red. On the other hand, blue colours are now 
actually produced in the arts by mixtures of green and violet, a 
result which has only become possible since colours of a very 
high degree of purity have been obtainable. 
Again, we do not distinctly see the meaning to be conveyed 
by the words “yellow, containing all colours is white in its ex- 
treme ;” and again, “ although yellow, as a colour, is explained 
away as white, it is nevertheless the colour yellow in endless 
tints and shades throughout Nature.” Frankly speaking we do 
not know what the “ extreme ” of yellow is. If we seek such 
an “ extreme ” we pass into green on the one hand, and 
into orange on the other. If we take a yellow solution — e.g., 
that of potassium dichromate — and dilute it with more and more 
distilled water, we get at last a colourless liquid. But we get 
the very same result by similarly diluting a solution of methyl- 
green or of eosine. When the author, however, puts yellow = E 
as the root of the fountain he seems to us to convey a truth 
which has been arrived at by other enquirers in a totally different 
manner. Yellow appears, in the evolution of plants and animals, 
to be the lowest stage of colouration, which Nature produces 
most readily, and at which she often stops short. 
Those of our readers who wish to pursue this interesting and 
most difficult subjedt will do well to re-read an article on “ Light 
and Sound,” by Prof. W. F. Barrett, which appeared in the 
“Quarterly Journal of Science” for January, 1870, and which 
Mr. Hughes here quotes. This eminent physicist also assumes 
the note C to correspond to the colour red, finds D correspond to 
orange, E to yellow, and F to green. 
Mr. Hughes says : — “ The twelve notes, scales, and chords in 
the major and minor series, &c., all agree so exadtly in their 
mode of development that if a piece of music is written cor- 
redtly in colours, with their intermediate tints and shades, the 
experienced musician can, as a rule, detedt errors more quickly 
