292 Miscellaneous Intelligence. 
young intricate theoretical sedan and giving promise e of res 
sults before unattained, not only with the new bieveriats, but (from an 
increased knowledge = its optical characters,) with those also, in com- 
on use among 
To falfill the sais which were imposed by these new laws, in 
connection with those enema announced by Lister, it became a 
practical question how far skill in manipulation, to give the requisite 
curves, and mechanical Seetvaetind to secure most, if not all, the prac- 
tical matte ig required by the observer, could be made available. 
a half years since, I satisfied myself and others, that the 
limit esi by the high authority of Mr. Ross, to the angle of aper- 
ture, was erroneous, and that this limit had no existence short of 180°. 
The question whether theory eee bounds - human skill, nnd thus 
satisfactorily determined, a question ‘no less serious arose as to the 
means to be employed to make the largest stainable angle of pei 
© years since, angles of aperture of 170° were obtained by me, os 
a sacrifice of the working focus seemed then an insuperable bar 
the employment of such objectives, as ordinary working and ssailable 
powers. Every increase of their capacity in one direction, seemed 
ee at the inevitable expense of some — necessary capacity in 
another. 
croscope as a a pertvee pei tet nt. 
Such, » then, is a brief sketch of my labors in connection with a 
but to a "earalons Study of the characters he ials them- 
selves,—the disc very of new qualities and capacities in glass, t new 
laws 0 combination, the union of the various cpa 
eevee Co Plate Engravings on Stone, (from @ letter 
from Lieut. oe Seems; 4 o J. D. Dan ademas New {from Jan. 17, 
1852.)—I enclose some nee ns of lithographic oe printing of 
the plates to be in the ' forthcoming Coast Survey Report { assume 
that you are interested in any moe of this kind, and the specimens we 
are now obtaining show so grea an advance that it is worth reporting: 
The process is briefly as follows. A copper plate being duly en 
graved, it is inked and an impression is taken on transfer paper. A 
good paper, which wetting does not expand, is needed, and a fatty 
coating is used in the process. ‘The transfer paper impression 4 
laid on the smooth stone and run t hrough a press. It is then wetted, 
heated and stripped off from the stone leaving the ink and fat on its 
