82 
Komances, 1801, p. 123, and in the notes to Beckford’s 
Vathek.) 
The value of green is an ancient belief. “Wise archi- 
tects,” says Isidorus of Seville, “ do not gild the ceilings of 
libraries, because the glitter might injure the eyes, and 
they pave them with green marble, for that is a colour 
salutary to the sight.” Calderon, in one of his fine passages, 
says : — 
“ La verde es color primera 
Del mundo, y en quien consiste 
Su hermosura.” 
Mahomet had the true poetic feeling in this matter, for a 
portion of his pleasures of Paradise was that the true 
believers should delight themselves lying on green cushions 
and beautiful carpets. 
The late Mr. C. Babbage, F.B.S., whose philosophic 
spirit illuminated every question he discussed, made 
numerous experiments to discover the shade of colour 
most suited for reading as causing the least strain to the 
eye. He was then preparing his logarithmic tables, 
and a “Specimen” exists in 21 volumes, printed with 
different coloured inks and on variously coloured papers. 
“The object of this work,” he says, “of which one single 
copy only was printed, is to ascertain by experiment the 
tints of the paper and colours of the inks least fatiguing to 
the eye. One hundred and fifty one variously coloured 
papers were chosen, and some two pages of my stereotype 
Table of Logarithms were printed upon them in inks of the 
following colours Light blue, dark blue, light green, dark 
green, olive, yellow ; light red, dark red, purple, and black. 
Each of these twenty volumes contains paper of the same 
colour, numbered in the same order, and there are two 
volumes printed with each kind of ink. The twenty-first 
volume contains metallic printing of the same specimen 
in gold, silver, and copper, upon vellum and on variously 
