H. L. Smith on a new Growing Slide for the Microscope. 241 
not clearly illuminated, say with } in. objective, a little fingering 
of the reflector, or r diaphragm, will suffice to effect this. The 
_ Screw which moves the draw and reflector may now be with- 
____ drawn, uncovering all but about a quarter or one half of one 
. side of the posterior lens of the objective; and, if care has 
___ been taken to prope rly ae the diaphragm os reflector, a 
fie fre 
ae ete 
Sp ae A. 
: The Risciine are especially beautiful, and no one can view, 
without a sense of Bi as: reverence and unspeakable emotion, 
the elegant aang of Arachnoidiscus and Heliopelta; of Sur- 
irella or Pinnulari 
In thus accomplishing the illumination of ope objects un- 
der the highest powers of the microscope, a powerful aid to in- 
oe is furnished, which, I doubt not, twill be rightly ap- 
Teclate 
An ba eeeriended microscopist may find some difficulty at 
first, but a few trials will ensure success, and when property 
et is no wank of light with the ath or ;';th even wit 
the B or C eye-piece 
— 
Arr. XXV.—On a new Growing Slide for the ee: by 
H. L. Surry, Kenyon College 
Iv studyin h and conjugation of the Diatomacezx, I 
have felt “Se llaag gee meat 3 keeping them alive for a 
time under the microscope; and have devised for this pur- 
Pose, the slide to be describe which appears fully to meet all 
Tequisi “treateat iheitek - in can be readily made by any tolerably 
“tap ist, it will, I am certain, be considered a valu- 
addition t es srpsler ical a 
: “te whole slide, as I aed oie it, is a trifle more than 
7h of an inch in thickness. It consists of two ryesg glass 
P. X2in., and about 5) in. thick, separated by thin strips 
glass of the ; same thickness, cemented to the sitatiest opposed 
-#,28 Shown in the figure. 
nods cl closed te I lkimately destined to be filled hem es is 
hot of such th ss as to prevent the os of the 
condenser, a i nips requisite. The glass I ny apap 
hen no Sentas, Vou. XL, No. 119.—Supr,, 1865, 
31 
