PART I. 
TECHNOLOGY. 
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I. THE LIGHT. 
SUNLIGHT is the best and cheapest light for pho- 
tography, and those who propose to make photo- 
micrographs are advised to make use of it in 
preference to any other, unless circumstances pre- 
vent them from working during the daytime, or 
they are in a locality where the full light of the 
sun can rarely be obtained, in consequence of 
clouds, fogs, or dense smoke. 
Photographing Transparent Objects by Transmitted 
Light. 
For powers up to one hundred diameters, light 
reflected from the clear blue sky and transmitted 
directly through the object, without the interven- 
tion of a reflecting mirror or condensing lens, is 
all that is required. Beginners are advised to 
make their first efforts with a simple apparatus 
arranged to use the light in this way. Not only 
is the necessary apparatus the cheapest and sim- 
plest possible, but the light is of the best quality. 
Being reflected from a perfect mirror, — the blue 
