Microscope Eyepieces. 
All eyepieces except Nos. 3253-5 are made to fit easily into the Royal Microscopical Society’s 
No. 1 Standard, -917 in. diameter. They are designated by their focal length, and their magnifying 
power is given for the distance of distinct vision 250 m/m., and is engraved on each eyepiece. 
Eyepieces Nos. 3253-5 are of the large size to fit the 1-41 inch R.M.S. gauge. 
Huyghenian eyepieces 
Focal Length. ee Power. 
No. 3260 ee 42 m/m. a x6 : ee = On aaO 
No. 3261 Hee 2053 ee na x10 OMB 
No. 3262 ae I fees eee ae x15 a ae Fe Alec (0) 
No. 3798 gal 105 oe ane x 25 aa ae ene OTS a0 
No. 3253 as 42, te “a x 6 2 5 0 
No. 3254 ie 25a F, Bas es x 10 De tT) 
No. 3255 . cae x15 ae Sa meee) (0) 
No. 3263 2D 4, with indicator «10 bs net ao Oa) 
No. 3264 Ey epi ece Nos. 3260 to 3262, with cross lines. oe 23; » OME AO 
Compensating eyepieces. These eyepieces are specially corrected for use with apochromatic 
object glasses and should always be used with them to obtain full advantage of the corrections of 
these object gla ses. 
Focal length. means pone 
No. 3266 a 45 m/m. oe a <i £22 @ 
No. 3267 oe SOs Nee se as x 8 2) 22 0 
No. 3268 oes 22 3s sak 8 oe x 11 Zoo O 
No. 3269 sa May she as a5; ey Z=LONSO 
No. 3270 ae LOW G 560 sls ae x 25 2 10 (0 
No. 32708... des - se oe x 37 3 io. 9 
No. 3270A ___... Das ree we cas x 50 3.3 0 
No. 3270c ph Sree ae ae 100 AA 
Projection eyepieces. These are specially aoprecten ee photomicrography und projection 
and give a flatter field than the lower power Huyghenian and compensating eyepieces. 
Focal length. Magnifying power. 
No. 3685... ae 42 m/m. oes a x G aoe er a spe 7) 
No. 3686 ... ee IY a x10 =e eat Soe LOO 
Wide field eyepieces. These eyepieces give a field of view about 40°, larger than either the 
Huyghenian or compensating eyepieces and are especially useful for searching. They also have an 
advantage for those who use spectacles in that the eyepoint is further away from the upper lens. 
Focal length. Magnifying power. 
INOSST 13) 2% sist 25 m/m. tes sas «10 he ee =p sree iG 0) 
NOFSTI4 ©. shs 21S; Ns ae «12 ian see woe ole Toe, 
Now Si (On... sais Wiese ss ee x 15 ae olan ao oe 0 oe 
No. 3778. Double demon- 
stration eyepiece .. {8 15 0 
In instructional work, an 
observer using a microscope fre- 
quently desires to show the 
object under examination to a 
second person and point out 
some feature which he wishes to 
demonstrate. This is difficult 
with the ordinary microscope, but with the double demonstration 
eyepiece two persons can observe an object at the same time. A 
movable pointer is provided which is visible in both fields, so that any particular 
part of the specimen can be indicated. The great assistance which this piece of 
apparatus can render in teaching can be readily realised. 
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