rotatom the 
PREFACE. 
In the following pages we offer a descriptive and illustrated Price-List of Microscopes 
and their accessories, of our own manufacture. In the construction of the Microscopes it 
has been our aim to unite stability, firmness and compactness, with as great simplicity of 
construction as is compatible with the purpose for which the instruments are intended, • 
while at the same time we have endeavored to apply to this department of industry those 
approved principles of manufacture which result in the production of superior goods at 
moderate prices. Ipi V - ' - | ( 
'The general design of these Microscopes has been perfected under the direction of 
some of the ablest Microscopists in the United States, and the mechanical and optical work¬ 
manship is under the superintendence of t 'I - 
E. GUNDLACH, 
so long and so favorably known, as a maker of first-class Microscopes and Objectives. 
The Microscopes described in the following page^, have certain important features 
which distinguish them from all others in the market. Prominent amongst these are: 
Our new patent fine adjustment (see page 3), the german silver slide earner described on 
page 5, the periscopic eye-pieces described on page, 15, the hemispherical immersion con¬ 
denser, described on pages 13 and 14, etc., etc. 
For the stages of our Microscopes we have adopted either hard-rubber, which, besides 
other advantages, Cannot be injured by liquids in ordinary use, or thick glass plates highly 
polished, which reduce the friction of the bearings of the slide carrier to a minimum. 
Our present series of objectives, constructed after new formulas, worked out by 
Mr. Gundlach, are. unsurpassed in all'those qualities that constitute a first class working 
objective. The lower powers have the advantages of depth of focus and freedom from 
color; the higher ones will be fqund to unite therewith great resolving power, and the 
greatest possible working distance, as far as these latter qualities can be obtained without 
encroaching on the former. As an illustration, we may refer to our dry 1-6 inch object¬ 
ive. In this objective the resolving power has been developed at the expense of the 
working distance, as far as possible for a non immersion objective, and the working 
distance has been correspondingly reduced to its utmost limits. This objective is theie- 
fore especially adapted for observations of diatoms, where very thin covers are employed. 
We furnish each of our Microscopes, except Nos. 510, 520 and 522, with an Eye-piece 
Micrometer. Rules for using the latter will be found printed on the back of the Magni¬ 
fying Table, accompanying each Microscope. These rules show a simple, easy and relia¬ 
ble method of measuring by means of an Eye-piece Micrometer, the size of the object 
under examination. 1 • v 
The almost indispensable camera lucida we construct in a new form, greatly simpli¬ 
fied, having not only the advantages of other well known Constructions, but needing 
Simply to be attached to the Eye-piece to be at once in proper position.^ We make them 
of different sizes so as to fit any Eye-rpiece. The axis and one of the pillars 
so as to indicate the proper degree of inclination required, to pk 
IO inches above the table. 
As a good magnifier is altogether indispensable to the Microscopist, we have under¬ 
taken the manufacture of three of the best kinds, the aplanatic triplet, a magnifier with 
two achromatic double lenses-, and the Coddington magnifier. , 
Our microscopes are furnished with hard-rubber Eye-pieces, which material we con¬ 
sider for seyeral reason^ best adapted to the purpose, a^d the prices quoted herein are 
calculated accordingly. If desired, we furnish brass Eye-pieges instead, charging the 
difference in price as stated on page 10. 
The sliding parts of the tubes in our instruments are all nickel-plated. 
All the cuts of Microscopes in this catalogue are one-third of their respective sizes. 
BAUSCH & LOMB OPTICAL CO. 
New York, September 1, 1877. \ 
rked 
the camera lucida 
George Er 
