Achromatic: free from color; tissue that does not stain readily.
An achromatic grating, however, is (rashly speaking) an impossibility.
The bands are then achromatic in the sense that the ordinary telescope is so.
If not, the substitution of an achromatic lens will be of no advantage.
Given the achromatic object-glass, why should not it be divided?
The achromatic doublets have a very large, clear and flat field.
Thus it is proved beyond all question that the lenses of the eye do not form an achromatic combination.
Fourthly, there is the contrast of colour and neutrality, the chromatic and achromatic, or hue and shade.
This object-glass is under corrected in point of colour, and wants to be made longer in the focus to be achromatic.
Each instrument carries six, five of which can be attached at pleasure either to the catadioptric or the achromatic.