The instantaneous centre of CD will be at the intersection of AD, BC, and if CD be drawn parallel to CD, the lines CC, DD may be taken to represent the virtual velocities of C, D turned each through B a right angle.
The inner platinum ends DD of the wire may be sealed into the glass insulating tubes, but reliance should not be placed upon these sealings.
These are old stem endings left after the loss of the original -es; thus latro gives lleidr, latrones gives lladron; the forms having dd represent i stems, i becoming dd in certain positions.
A consonant occurring medially is, generally speaking, invariable in the present language; thus the p and d of cupidus are b and dd in cybydd; but with the initial consonant the case is different.
While the limiting of the pencil is almost always effected by the objective, the limiting of the field of view is effected by the eyepiece, and indeed it is carried out by a real diaphragm DD arranged in the plane of the real image O'O 1 (fig.