O. N. Rood on Dove’s Theory of Lustre. 339 
Art. XXX.—Upon some Experiments connected with Dove's 
Theory of Lustre; by Prof. O. N. Roop, of Troy. 
in combination with iaaaiiee reflected, or dis isper rsed kt 
ustr re.” 
Scope and viewed through a plate of violet ee produced, in 
the act of combination, the idea of a polished metal. 
Similar to Dove’s theory of lustre is that of Prof. Ruete.* 
This view of the nature of lustre opens to us the possibility 
of reproducing by the stereoscopie combination of suitably col- 
ored surfaces, the individual lustre and appearance of gold, 
copper, brass, &c.; it also affords us a means of examining a 
arately the cctnpenaiia which may produce the appearances 
peculiar to eac 
. T combined in the ton on white or on black grounds 
—a piece of tin-foil one inch square with a piece of yellow paper 
of the same size. The value of the tint on the chromatic circles - 
of Chevreul was, Ist Cine orange-yellow, No.4. When the 
mbining in the same way tin foil with orange-tinted 
paper, st circle, orange,) the lustre and appearance of copper 
3. Te in- awit in the act of oe with Nos. 14 and 15 of 
ar ted and black scale imitate bism 
4. Tj in-foil or silver-foil in the act = combination = ultra- 
tain paper appears scnbtialy blue, rather black like f oliated 
a pve 
5. Gold-leaf i in combination w aper of of a dint nearly that 
of the green of the Ist circle nes 
6. Gold-leaf in combination with ft paper resembled 
a surface of graphite. 
* Das Stereoscop ; C. G. Th. Ruete, Leipzig, 1860. 
