CHAS. LENTZ & SONS 
Hcbromatic Objectiues 
CORRECTED FOR m MM. TUBE LENGTH 
HESE objectives are those supplied with all stands listed. They 
are made by Bausch and Lomb Optical Company^ Rochester, 
New York, a firm whose reputation for the highest class of 
optical work is universal. They are specially corrected for us 
for medical microscopy and biology. 
We believe that for working distance and penetration they are not equalled by 
any objectives of similar type. The flatness of field is very good and is all that 
can be desired, while for definition (the most important of all qualities required 
for medical work) they are unexcelled by any other objectives of either 
domestic or foreign manufacture. 
The J-J2 oil immersion objective is worthy of special notice. It is manu- 
factured after a new formula embodying optical glasses which do not dete- 
riorate and is specially corrected for bacteriological work. 
The numerical aperture is high (1.32) and as the chromatic and spherical aber- 
rations are properly corrected and the amplifying power great, the resulting re- 
solving power is excellent, rendering the objective exceptionally useful for 
biological work. 
It has been remarkably well received and is highly advocated by the large 
number of prominent bacteriologists, biologists and physicians who have 
thoroughly tested its capabilities in daily laboratory use. It has made many 
converts from those who previously had solely depended on objectives of foreign 
manufacture. 
We confidently invite comparison of this objective with the best of other manu- 
facture and will cheerfully send it for examination to responsible parties under 
conditions as stated under notice, page 3, § 3. 
We are quite confident that these objectives have no equal at the price and 
that they are unexcelled by many which are much higher in cost and are more 
pretentious. 
Every single part of these objectives is tested and re-tested many times 
before and after assembling by different skilled mechanics and opticians, it is there- 
fore impossible for a faulty objective to leave the factory, and they are again 
examined by us before shipment from Philadelphia. 
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