178 REPORTS FROM THE SECTIONS. 
balsam between two thin covers so that the full angle of the 
remark. The definition of the exclamation marks is fine, but no 
better than the water immersions. There is a good deal of colour 
on this test of a reddish tint, similar to that shown by Zeiss’s old 
G’ e field is very flat ; in this respect the lens surpasses any 
I have yet seen of the same focus. 
From the trials I have made of this objective I am convinced 
of its immense power on close-lined objects, and this, of course, 
power of grasping rays of an extreme angle. As It 
se 
positive advantage, obviating the necessity for the extreme polish 
required when using other lenses, as the nature of the medium 
prevents the breaking up and diffusion of light by rough surfaces 
I would add a word in reference to one of Zeiss’s latest water- 
immersion (G) {ths received with the oil lens. My own G by this 
maker was made about three years ago, and the present objective 
is one of his best and latest of that class. Zeiss has certainly 
justing for covers from -003 to 007. The new G ranges 
10 to 23 divisions on the collar, equal to covers from ‘004 to 009. 
The adjustment for the increased thickness is undoubtedly 7 
advantage ; but it is a pity Zeiss did not give the new lens 2 
back to 003, as many bought slides of tests have covers © 
that thickness. In resolving power there is nothing to cae 
tween the new G and my own; they are both fine glasses 
this and will show every possible test that their aperture 
is capable of. I made many trials of both on W. Crrassimert™, 
and any lines visible in the one could be seen by the other. pe 
the Podura scale the new lens was the most achromatic— ers 
markings were quite black; in my own they are slightly 
appears to vi 
Zeiss e succeeded with his new water fn. 
