248 THE OPEN BOOK OF NATURE 
The best kind that can be had for this purpose is a 
Prism Binocular, but such an instrument is rather 
expensive. There are, however, good glasses which 
are to be had secondhand, or even new, for a 
moderate sum. I often use a glass which I pur- 
chased for half a guinea ; it enables me to observe 
the ‘ points’ of birds with great accuracy. The 
same glass serves for occasional observation of 
insects, and it has often enabled me to identify 
plants which I cannot reach without great diffi- 
culty, and which, at a distance, are not clear to the 
naked eye. 
No naturalist moves about without a Pocket- 
Magnifier ; it is useful in a hundred ways, and need 
not be expensive. One can be got as low in price 
as sixpence, and a shilling glass will do very good 
work. Of course, higher prices can be paid. For 
some time I have carried a pocket-magnifier having 
three lenses, which can be used one, two, or all three 
at a time, according to the magnification required. 
I think it cost me three and sixpence. The best 
lenses are the Platyscopic or Aplanatic ; they give 
splendid definition, good magnification, and have 
ample working distance, but they are rather ex- 
pensive. 
A Microscope is not absolutely necessary for 
ordinary observation, but it is a most delightful 
instrument to possess. One can be a good naturalist 
without its assistance, but it unquestionably opens 
up fields of inquiry that cannot be tackled without 
it. A hand-magnifier can be rigged up on a stand, 
and made to render good service in the observation 
and dissection of small objects. Thus arranged, 
