, 1879-02-02
MAGNIFYING-GT4ASSES.
The Famous TolIes One-Seventy-
Fifth Objective.
It's Exhibition at the New YORK
Academy Of Sciences, and
the Results.
Prof. Fa;rne1d's Discovery or IN 1nl-
portant improvement IN tile
Microscope.

portant improvement In 1no
Microscope.
From Our Ou4 Corrt:pondsn@
NEW YoRK, jan 3D.-The recent exhlhltlon'
at tile New York Academy OF Sciences, q .''S
famous Tollcs one-seyenty-lfth objective mas
given fresh interest to the Improvements III tne
microscope, and las attracted the attention OF
scientific men to the question OF wna1 eau Nc
expected Of such lenses in tile way o. e1ae'
optical analysis, beyond what can oe accoi'-
plisheu 5y a ouc-twcuty-i1th 1t was pret1s
generally concluded at the Academy tne otne,
nght-colorcd corpusces from human o'oou
uc:ng the test obiects-that what was Raiheu IL
maguifying power was lost In penetration anu
definition. And such actually was Tue cas7
with the method OF illumination nsed ps ~
Ephraim Cutter, OF Boston. the reader ol tne
paper on that evening". The corpusclcs nao tne
appearance Of pale, somewhat 1alntly'outlsneo
drawings, without relief, without structure
PROF. r. G. FAIRFIELD,
who spoke briefly to the subject ol the paper
was not satisfied that the method OF illu1nlna-
tion was sound one, and pointed out the 1act
that the central rays should always be excluded
in illuminating high power lenses, II accurate
results we're to bc obtained. The best method
to effect this purpose WAS to use condenser OF
considerable aperture, and revolve the dla-
phragm Of the microscope until tho larger OPEN
ing cut of about threc-1i[ths Of the light,-thus
illuminating the object By means OF a paraooilc
section of the condeusinr lens. Prof. Fairfield
added, however, that Il power OF lootk0 DIANE
tcrs possessed no advantage over power OF
2 800 in the study of organic life. The reason
was this: that the latter power was amply sui
fcicnt for the optical analysis OF the monads
appearing in animal secretions,-th monads
being the miuutest living bodies yet discovered.
II it could be hoped to test the molecular strhc-
ture OF albumen by direct optical analysis, such
lenses as that on exhibition constituted
A SUBSTANTIAL ADVANCE.
he Judged the Tolles objective to have power
of about 5000 diamcters, while it would require
ut least Loo, 900 diamcters to make successful
attack on the molecular structure Of living mat
ter, granting that molecule was real thing,
and that the molecule Of albumen was twenty
times as large as that OF water. AS 100000
dlametcrs could not be hoped for hy any meth
cd Of combining lens-systcms which had yet
been exhibited, the Professor did not see any
special value in a ouc-seyenty-1fth over Prof.
John G. Draper's oue-twentleth Beck, or the
Wales ouc-twentieth. From his own expert
ments, Prof. Fairfield had become satisfied that
an objective composed Of three lens-systems
must always fail ia analyzing power. He could
not give any optical reason why two ]ens-sys-
tens should Increase both the defining and pen-
etrating power OF an objective, while IN object
i've composed OF three showed such reuarka-
bic deficiency In both these properties The
fact was so, and that was
SUFFICIENT FOR PRACTICAL PURPOSES.
Fnr rrfo prr,f
Clark, of Harvard Collcge,-the first one~twen-
ty-second,~ by the way. ever manufacturcd,-
yielded. according to that: accurate worker,
power OF $500 liamcters. Or. L. G. Hartman,
OF Boston, has the only onedftieth in the world,
rs well Us the only one-seyehty-hfth objective
The form 3r has power OF 5000 diameters.
The investigation respecting the structure of
colored blood-corpusc1cs, upon which paper
was recently read before the Biological Section
Of the Acadey By Dr. Lewis Gisoerg was con-
CT Of 1000 diarnetc1s- 1n:rcmarking upon the
points Of DR.. Elsberg's paper, Prof. Fairfield
said he had been aware for more than two years
Of the phenomena described, having published
previously Us phenomena constantly associated
with the dissolution resolution into other
forms-of blood-corpnscles. But he had never
found any such structure ID fresh corpuscies
from healthy animals. As the whole question
TURNS ,upoS THE PROPERTIES OF LENSES,
it will be interesting to note that the celebrated
one-twenty-tifth in the collection Of the late
twentieth employed by the late Dr. Stanley,
have both been brought to bear on the question
raised BY DR.. Elsberg by one OF our most ac-
complisbed microscopists, prof: David G. Com
stock. The results obtained were entirely
ncgatived. Prof. Fatrfeld's views were based
upon the concurrent testimony OF wide-angle
Powell s. Leland one-tenth, 4 Hartnack one
twelfth, Wales one-sixteenth, and compound
onc-tenth Of very peculiar construction; IN
vented by himself. This new objective has been
carefully examined by members Of the National
Academy OF Sciences, and pronounced By them
the greatest advance in optical analysis since
the discovery Of the principle Of the compound
microscope.
Knowing that many of THE TRIBUNE readers
are interested In the subject, l obtained from
Prof. Fnirfield
DESCRIPTION OF MS INVENTION.
The construction is very simple, aud Involves
only two lens-systcms, preserving all the work.
ing properties OF the original one-tcnth upon
which it is based, while exceeding the Tollcs
one-seventy ty-Gfth in power and definition. The
structure of the surface OF the blood-corpuscle
is by this instrument distinctly shown at i pow
er Of 10,450 diameters, such that single cor
puse1e fills tue whole field ol the instrument,
with the exception Of = very narrow margin.
That is to say, while the diameter of blood
corpuscle is about one-three-thousand-an d-andtwo-
hundrcdth of an inch, the diameter OF the pen
ell OF light transmitted is one-two-thousanGth
Of an inch. The field Of the Tolles lens is large
enough to contain five corpuscles. Prof. Fair
fields lens differs from all high-power lenses
yet attemp ptcd, IN the use Of small condenser,
double convex, interposed between the two
lens-systems III such a manner as to increase
the illumination while ut the same time i'm
mcnsely increasing the angle. OF the two lens
systems, the first is mounted Negative, the con-
yexity pointing inward the second positive, or
with the convex surfaces pointing downward to-
ward the condenser.
THE CONDENSER
is larger section OF 9 sphere, Of exactly the
same foru,ulary Us the several lenses OF which
each lens system is COMPOSED. The optic PEN
Gil travels half an inch after passing through
the first lcns-systcm.. Its middle rays arc then
taken up b. the condenser and concentrated.
The second lens-systein receives the concen-
trated pcucil onc-esnth OF all inch within the
proper focal distance of the condeuser,-tAe re-
suit being 1 width OF angle that has hitherto
been regarded Us entirely unattainable and
power that is equally astonishing. The arrange
mcnt is one Of go singular simplicity that the
wonder is that it should not have OCCURRED TO
somebody years ago, instead OF being LETT to tile