ii SCIENCE—ADV ERTISEMENTS 
NEW JENA LABORATORY GLASS 
as recently perfected by Messrs. Schott & Gen., Jena, Ger- 
many, differs from the old in 
an increased power of resistance to sudden changes 
of temperature 
and a reduction of the amount of alkali given off 
into aqueous liquids 
This glass may be used without wire gauze for heating liquids 
directly over a powerful Bunsen flame, thus resulting in a great 
saving of both time and gas. Every piece bears the trade-mark of 
the manufacturer. 
We carry a complete stock of Flasks, Beakers, Retorts, Test 
Tubes, Glass Tubing, Evaporating Dishes, Reagent Bottles, etc., 
in the above glass and are in a position to fill orders promptly both 
from stock on hand and by ‘‘duty free’’ importation. 
Special price list of the new Jena glass 
sent upon request 
ARTHUR H. THOMAS COMPANY 
IMPORTERS AND DEALERS 
MICROSCOPES, LABORATORY APPARATUS AND CHEMICALS 
1200 WALNUT STREET, PHILADELPHIA 
About a year has passed since 
The Leitz’ Student Microscope 
‘‘ Stand II O”’ 
was introduced. During this interval we have observed, through 
the rapidly increasing demand for this particular model, the great 
favor it has met with amongst educational institutions. 
To make impressive the features of Stand II 0, we wish to 
briefly mention some of them as follows: 
The Arm-—curved, allows for the carry- Fine Adjustment—Absolutely dust- 
ing of the Stand without injury to the proof with safety device for objectives 
most delicate parts. and specimen. Lost motion im- 
The St —105x105 mm., covered mosrible: 
Tee Sias = 0 Finish—ofarm and base—burnt in black 
with heavy Hard rubber plate. _ annnGil 
Stand—consists of only two parts,con- Optical Center—at distance of 80 
nected by powerful joint (rigidity min, from arm (convenient in exam- 
guaranteed). ining large objects). 
Objectives—of the well-known LEITZ’ STANDARD. 
Duty free prices to educational institutions. Send for literature. Ag 
Uv. S. é ST LE 30 East 18th Street 
NEW YORK 
