Opticks 1717 - Up

29
so by looking on the %&through a Feather
or blick Riband held dlofe to the Eye, feveral
Rain-bows will appear ; the Shadows which the
Fibres or Shreds cait on the TPks&z Ret&u, being
border’d with the like Fringes of Colours.
O~J 3. When the Hair was twelve Feet diitant
from this Hole, and its Shadow fell obliquely
upon a ‘flat white Scale of Inches and
parts. of an I?ch placed half a Foot beyond it;
and alfo when the Shadow fell perpendicularly+
upon the fame Scale placed nine Feet beyond
it; I meafured the breadth of the Shadow and
Fringes as accurately as I could, and fo&
them in parts of an Inch as follows.