
Tae NorTaern Muicroscorist. 



No. 14. FEBRUARY. 1882. 


A VISIT TO AN OBJECTIVE FACTORY. 
N page 105 of Pritchard’s Microscopical Cabinet we read, 
“Nearly all the naturalists who have distinguished themselves 
by their discoveries with the microscope have rejected the com- 
pound instrument with its luxurious field of view and attached 
themselves solely to the single instrument”; and again, “The 
great loss of light in the ordinary compounds, with the consequent 
absorption of all the delicate tints and colors of an object, makes it 
appear like a coarse engraving in black and white. This added to 
the great and sensible dispersion which envelopes every object seen 
through them in a false prismatic halo, and utterly obliterates all 
its delicate markings and structure, renders this instrument almost 
useless for investigation.” Such seems to have been the general 
opinion many years ago, but when we look around us at the present 
moment, it would be difficult indeed to find anyone willing to 
endorse such views. 
Microscopic Objectives are looked upon with a great deal of 
superstition by nearly all microscopists, most workers taking very 
special pains not to learn anything of the optical principles of the 
appliances with which the tubes are fitted, but we hope that the 
time will come when every possessor of a microscope will be 
familiar with the optics of his favourite study, and no longer look 
upon an objective as something too deep to be fathomed, and of 
which, therefore, the less said the better. 
Objectives, as they are made now-a-days, are remarkably free 
from imperfections, that is if we consider the spherical and chro- 
matic aberrations only, and there is in the market an abundance 
of really good lenses, at very moderate prices, and capable of doing 
an immense amount of work. 
The beginner must, however, understand that the construction 
of a really first-rate objective, of wide aperture, is an expensive 
matter, so that one cannot be produced at the nominal price 
charged for some lenses, and as in the present diffusion of micros- 
copical knowledge cheap lenses will always be enquired for, most 
opticians make two or three series of objectives, each differing in 
Price and quality. A novice would be unable, perhaps, to discover 
any distinction between an inch objective of 18s. and one at £4, 
but an old hand would have no difficulty in detecting the difference, 
Vomuics ; 

