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A aaea CAREA ENE T. PEL AEE RAS PENALE EE 8: 
a tens r Ne T E TT O 
1878.] Microscopy. 193 
or in any desirable position above it. The obliquity of illumina- 
tion is indicated by graduated arcs. The sub-stage itself has cen- 
treing and rotating as well as vertical movement. 
The fine adjustment has been removed to the same position as 
in Zentmayer’s recent stands; but instead of a separate slide, the 
levers act upon the body by means of the rack itself, by moving 
steadily, up and down, the box in which the pinion of the coarse 
adjustment acts. This is forced upwards by a direct action, and 
downwards by a spiral spring. Great steadiness is attained, as well 
as the ordinary advantages of removing fine adjustment from the 
nose-piece. The nose-piece, however, is movable vertically, and 
has a safety spring as in the usual form of fine adjustment. 
he stage is mounted on such a level that when the tube is placed 
vertically the axis around which the instrument rotates at the base 
will pass through the object on the stage, and consequently through 
the focal plane of the objective and of the illuminating apparatus, 
giving great advantage for optical experiments. The stage itself 
is sufficiently thin to admit an obliquity. of illumination of 67 
degrees without special appliances. It has graduated hori- 
zontal and vertical movements by means of a screw and a chain 
moved by milled heads upon the same axis; also a mechanical 
and graduated rotation around a centre which is easily adjustable 
to the axis of even a high power objective. It is also supplied 
with Brown’s iris diaphragm. The iris diaphragm is furnished 
with the society screw so that it can be, if desired, either 
used in combination with an achromatic condenser, or used as an 
adapter above the objective itself so as to reduce directly the 
angle of light in the instrument. 
Besides thi perb inst t, Mr. Bulloch | ller stand 
specially suited for diatom work, but well calculated for general use. 
i SS fg E + 
Itis nearly equal to the larg p ' every 
but size, and has a stage (rotating but not mechanical) sufficiently 
thin to admit light at an obliquity of 73 degrees, and reversible so 
that the slide can be used on the under side with light at any de- 
sired angle up to go degrees. He also introduces several styles 
of small and low priced microscopes in which some of the most 
excellent and popular English and American stands are repro- 
duced with ingenious additions and improvements. 
These instruments are beautiful in form and of excellent work- 
manship, and they add another notable item to the recent valu- 
able contributions of American workers in this department of 
science. 
+ 
Microscopicat Suppiies.—Mr. Chas. Petit, of 151 High street, 
Stoke Newington, London, England, is sending cover glasses and 
_ other small supplies to this country promptly and at a low price. 
_ One ounce of thin circles are sent postpaid, for $1.25, or if thinner 
_ glass for $1.50. Two ounces of squares and circles mixed are 
