266 REPORT—1852. 
(33) 102. OLIVE-GREEN.—-Green of spectrum somewhat more yellow; 
the violet diminished by an elongation of the indigo; the violet appearing as 
a border to the indigo only. 
(34) 103. Deep oLIvE-GREEN.—Red flowers not to be distinguished from 
the green leaves; spectrum diminished to red, yellow and green rays, the red 
being very much reduced in extent, and the yellow and orange blended. 
(D.) Series of Blue Glasses. 
(35) 49. A LIGHT BLUE, fig. 13.—The spectrum is represented Fig. 13. 
in its three primary rays, suffering a little reduction in length ; when a 
concentrated by a lens a little violet appears at the extreme edge. 
of the blue. Natural objects do not suffer much change when ob- 
served through this glass; purple flowers lose more of their red 
than blue, and violet-coloured ones appear nearly pure blue. 
(36) 46. INTENSE COBALT-BLUE, fig. 14.—The ordinary red ray 
disappears, and a pure crimson ray, the extreme red, is seen below 
the lower edge a! of the ordinary spectrum and extending up to the 
mean yellow. All the rays but the blue, which becomes very 
intense, and a trace of violet at v, are ob- 1 Fig. 14, 2. 
literated, the red rays being sharply cut off at aula 
y, between which and the blue a dark band 
appears. When concentrated by a lens, the 
spectrum is changed, as shown in (2). The 
lower crimson ray at a’ becoming a defined 
circle, surrounded by a band of intense black- 
ness, which extends to the second circle at y, 
which; instead of being crimson, as was conti- 
nued in the neck of (1), is now of a lavender 
hue, from the mixture of some yellow with the 
red, the blue is condensed, the black at the lowest edge being an intense 
indigo. 
(37) 3. CoMBINED BLUE AND GREEN GLASSES, fig. 16.—Looking at the 
spectrum through these glasses, every trace of red is obliterated, the resulting 
spectrum being a pure green and blue. Making the rays pass from fig. 16. 
the prism to a lens (fig. 15), and causing the concentrated rays to 
Fig. 15. 


a 



es 
permeate this combination, the result is somewhat more decided. The spec- 
trum is not shortened at the most refrangible end, but the red of the violet 
is entirely removed, forming a pure blue patch equal to *8. Over the space 
marked g the green is far more luminous than over any other part, and the 
rays gradually darken towards the lower end. 
(38) 105. DEEP COBALT-BLUE, fig. 17.—The red of flowers, as of the 
Fuchsia, &c., is entirely lost, and not to be distinguished from the green leaves. 
The surface of leaves appears a grey or blue, with a few exceptions ; the Arbor 
vite assumes a red-brown colour, remarkable from the striking contrast it 
makes with the surrounding trees. The leaves of the Currant and several 
