For example, the condition for achromatism (4) for two thin lenses in contact is fulfilled in only one part of the spectrum, since dn2/dn1 varies within the spectrum.
Achromatic Eye-Pieces of Telescopes, and on the Achromatism of Microscopes.
Footnote 6: The low dispersive power of water masks, as Helmholtz has remarked, the imperfect achromatism of the eye.
Thus examined, the departure of the eye from achromatismappears very gross indeed.
While these practical investigations were in progress, the subject of achromatism engaged the attention of some of the most profound mathematicians in England.
Close study of the formulae for achromatism given by the celebrated mathematicians we have quoted will do much, but the principles must be brought to the test of repeated experiment.
The explanation in question is of a purely physical character, and depends upon the non-achromatism of the eye.
These phenomena are fully explained by the imperfectachromatism of the eye.
A change probably takes place in the humours of the eye, through which their achromatism is affected.
When a chemical property produces its effects under all these circumstances: this we have already entered into more fully under the head of achromatism and hyperchromatism.
