4o6 Dr. Brewster on new Properties of light exhibited 
II. On the communication of the properties of Mother of Pearl to 
other bodies. 
The phenomena which have now been described must be 
admitted to be very singular and instructive, even if the in- 
quiry had been pushed no farther; and it is probable that 
philosophers would have contented themselves with ascribing 
them to reflections from differently inclined planes in the in- 
terior of the mother of pearl. 
In order to measure the angles contained in the preceding 
tables, I had occasion to fix the mother of pearl to a gonio- 
meter by a hard cement. Upon removing it from the cement, 
the plate left a clean impression of its own surface, and I was 
surprised to observe that the cement had by this means re- 
ceived the property of producing the colours which were ex- 
hibited by the mother of pearl. This strange result I at first 
attributed to a thin film detached from the plate, but subse- 
quent experiments soon convinced me that this was a mistake, 
and that the mother of pearl really communicated to the 
cement the properties which it possessed. 
I have also succeeded in imparting the same faculty of pro- 
ducing colour to black and red wax, balsam of Tolu, gum 
Arabic, gold leaf placed upon wax, tinfoil, the fusible metal 
composed of bismuth and mercury, and to lead by hard pres- 
sure, or by the blow of a hammer. When the impression is 
first made upon the fusible metal, the play of colours is sin- 
gularly fine, but the action of the air corrodes the metal, and 
speedily destroys the configuration, as well as the polish of its 
surface. The same effect was produced when the metal was 
immersed in oil. 
