PHILADELPHIA 
The coarse adjustment is by diagonal rack and pinion, the advantage of the 
diagonal teeth being that much greater delicacy of movement is secured, together 
with greater lasting qualities, as three teeth engage at all times and with a shear- 
ing contact instead of in the jarring fashion as with the straight rack. The diag- 
onal rack and pinion is entirely free from all back lash or lost motion. The 
main tube is of large size and has nickeled and graduated draw tube sliding in 
cloth-lined sleeve and taking standard gauge eyepieces. The sleeve-carrying 
draw tube is removable when using the stand for photography. 
The substage is the New Complete Substage as described on pages i8 and 19 
This microscope is made in two forms : 
DS with Revolving Vulcanite Stage. 
DDS with Revolving Mechanical Stage. 
DSl. Stand DS with i eyepiece, and i inch and ^ inch objectives . . . $130 OO 
DS2. DS I with double revolving nosepiece 135 OO 
I>S3. Stand DS with 2 eyepieces, § inch and ^ inch objectives . . . . 132 00 
DS4. DS3 and double revolving nosepiece 137 OO 
DS7. Stand DS with two eyepieces, i inch and ^ inch dry, and j\ inch 
oil immersion objectives 103 50 
DS8. DS7 and triple revolving nosepiece 171 00 
DDSl. Stand DDS with i eyepiece, ^ inch and ^ inch dry objectives . 160 OO 
DDS2. DDSi with double revolving nosepiece 165 OO 
DDS3. Stand DDS with 2 eyepieces, I inch and i inch objectives . . . 162 OO 
DDS4. DD S3 and double revolving nosepiece 167 OO 
DDS7. Stand DDS with two eyepieces, f inch and I inch dry, and Jo- 
inch oil immersion objectives 200 OO 
DDS8. DDS7 and triple revolving nosepiece . 207 50 
DDSIO. Stand DDS with 4 eyepieces, 2 inch, f inch and ^5 inch dry, and 
J- inch oil immersion, objectives and quadruple revolving nose- 
piece . . 222 00 
DDS12. DDSio with Filar Eyepiece Micrometer, Stage Micrometer and 
improved Abbe Camera Lucida 290 OO 
Plain revolving Stage for DDS, extra 10 00 
^ or -J will be substituted for }, if desired. 
