MEMORANDA. 
237 
malcules of an analogous kind, and which have not yet been 
studied." , 
A New Magnetic Stage.— In ofiPering the following sugges- 
tions to your readers, I do not profess to have made any new 
discovery, forasmuch that all the best works descriptive of 
the microscope mention, at least, a magnetic stage, and Mr. 
Busk has afforded a detailed account of such an apparatus 
in the ^ Microscopical Journal' for July, 1854 (No. VIII, 
pp. 280-1) ; but beg to suggest a far more simple, and I 
believe equally efficacious, form of instrument, which I have 
long employed with advantage, and which a sino^le glance at 
the accompanying sketch will suffice to describe.^ 
The microscope employed is that known as ^*^Waring- 
ton's;" the brass object-plate is replaced by one of oak wood, 
into which one of the common horse-shoe magnets is im- 
bedded, as shown in the drawing; the armature of the 
magnet thus becomes the object-holder, and provides com- 
pletely for the universality of movement of the object with 
a readiness and equability of motion only attained by me- 
chanical stages of superior construction. 
* The sketch is the size of the original ; the dotted lines represent tli@ 
"armature*' used as the object-holder. 
