[The usual compound lens is all that is required.]
Would you have the goodness to explain, in some detail, the two methods
by which Mr. Stewart and Mr. Kilburn multiply photographs in a reduced
or magnified size; the one by reflected light, the other by transmitted.
Mr. Stewart's experiments are upon glass, Mr. Kilburn's on cameras and
daguerreotypes. I have never seen any description of this latter process,
or of the method of preparing the stereoscope objects: vide _Athenæum_,
July 30, 1853.
I observe with great pleasure that the cost of apparatus is becoming
less, &c.