The faces of slates have usually a slightly silky lustre due to the abundance of minute scales of mica all lying parallel and reflecting light simultaneously from their pearly basal planes.
In England, Owen's anatomy of the pearly nautilus,14 Huxley's discussion of the general morphology of the Mollusca,17 and Lankester's embryological investigations, 19 have aided in advancing our knowledge of the group. Two remarkable works of a systematic character dealing with the Mollusca deserve mention here - the Manual of the Mollusca, by Dr S.
The shells of the pearly nautilus are commonly used by the Visayans for drinking cups.
The brood of bees, when healthy, lies in the combs in compact masses, the larvae being plump and of a pearly whiteness, and when quite young curled up on their sides at the base of the cells.
It has the characteristic appearance of pure silk - a brilliant soft white body with a pearly lustre - insoluble in water, alcohol and ether, but it dissolves freely in concentrated alkaline solutions, mineral acids, strong acetic acid and in ammoniacal solution of oxide of copper.
The different kinds of mica vary from perfectly colourless and transparent - as in muscovite - through shades of yellow, green, red and brown to black and opaque - as in lepidomelane; the former have a pearly lustre and the latter a submetallic lustre on the cleavage surfaces.
Their hair is dark brown or black, straight, wavy or curly; the beard is thin, the face broad, the profile not prominent, the eyes large and expressive, the nose somewhat flattened, the lips thick, the teeth excellent in shape and of a pearly whiteness.
Scouring renders all common silks, whether white or yellow in the raw, a brilliant pearly white, with a delicate soft flossy texture, from the fact that the fibres which were agglutinated in reeling, being now degummed, are separated from each other and show their individual tenuity in the yarn.
On the 29th of April, as I was fishing from the bank of the river near the Nine-Acre-Corner bridge, standing on the quaking grass and willow roots, where the muskrats lurk, I heard a singular rattling sound, somewhat like that of the sticks which boys play with their fingers, when, looking up, I observed a very slight and graceful hawk, like a nighthawk, alternately soaring like a ripple and tumbling a rod or two over and over, showing the under side of its wings, which gleamed like a satin ribbon in the sun, or like the pearly inside of a shell.
The interior of the shell is remarkable for the absence of pearly lustre on its interior surface.