NOTES AND CORRESPONDENCE. 
Bacillaria paradoxa in Fresh Water.—The occurrence of 
Bacillaria paradoxa in fresh water having been announced 
as a new fact in the last number of the Journal (p. 66), I am 
induced to state that in the ‘ Botanical Gazette’ for 1851 I 
recorded the detection of this species in a gathering from 
ditches near the river, a short distance above the town of 
Stafford. I may add that on more than one occasion after 
the publication of that notice I found the Bacillaria in 
gatherings from the same system of ditches, and on both 
sides of the river. It is remarkable that although Stafford 
is far from the sea, salt-loving Phanerogams have been found 
in its neighbourhood, e.g. Glaux maritima (L.) and Rumea 
maritimus (L.). There are salt works about five miles from 
the town in the direction of the localities for these plants, 
but the district where I found the Bacillaria is in the 
opposite direction and far removed from their influence.— 
Rozert C. Doveras, Stoke Lacy Rectory, Bromyard. 
Improvement in the Lieberkuhn.—In the examination of 
opaque objects with a bmocular instrument it is no slight 
advantage to have the quantity, the quality, and the 
direction of the ight, under complete control ; with the ordi- 
nary Lieberkiihn this is by no means the case, for although 
its advantages are very considerable, it is not without an 
accompanying disadvantage which materially lessens its 
usefulness. The great flood of light arising from the mass of 
converging rays thrown down i every direction upon an 
object tends to obliterate the appearance of all delicate surface- 
markings, through the want of a defining shade and shadow 
to render them apparent. In this respect, with the lowest 
powers, the bull’s-eye condenser and the side reflector are in 
the ascendant; but with the medium powers the obliquity 
