GROW AEROBIC AND ANAEROBIC CULTURES IN THE
GYROTORY®
INCUBATOR SHAKER A controlled temperature incubator with continuous shaking action. Agitation speed variable from 140 to 400 rpm. Triple-eccentric-shaft stabilizing system dis tributes positive rotary motion to every flask on the 18" χ 30" platform. Cool, quiet, smooth-running. , . ' M O D E L G25. C ι rculating heated air, the fully insulated unit provides constant tem perature, ambiient to 60° C , ± V 2 ° C Other speed r a n g e s , and connections for gassing avail able. Adapt able for tubes, bottles, and other glassware. Overall Dimensions:
2 5 " long χ 4 1 " wide χ 2 9 V i " deep.
UNCONDITIONAL O N E YEAR WARRANTY
CONTRIBUTED ARTICLES Polarographic Determination of Titanium in Tan talum and Niobium Concentrates and Ores . . .
1 836
D. K. Banerjee, C. C. Budke, and F. D. Miller
Polarographic Determination of rV,N'-Ethylenediglycine and Nitrilotriacetic Acid in (Ethylenedinitrilo)tetracetic Acid R. B. LeBlanc
1 840
Direct Quantitative Diffractometric Analysis . . . .
1842
P. P. Williams
Determination of Blood Urea with p-Dimethylaminobenzaldehyde H.H.Brown
1844
Extraction and Determination of Thorium from Sulfate and Phosphate Solutions with Tri-n-octylphosphine Oxide
W . J. Ross and J. C. White
1847
Determination and Stabilization of Reduced Ascorbic Acid in Extracts from Plant Materials . Η. Τ. Freebairn
1 850
Ion Exchange Membranes in Coulometry
1 852
Write for Catalog G 2 5 - A 1 1
NEW BRUNSWICK SCIENTIFIC CO., INC. P R E C I S I O N
L A B O R A T O R Y
A P P A R A T U S
P.O. BOX 6 0 6 , NEW BRUNSWICK, NEW JERSEY Circle No. 159 on Readers' Service Card
PARR
S. W . Feldberg and C. E. Bricker
Glassblowers'
GOGGLES
Determination of Organic Nitro Compounds by Controlled-Potential Coulometry J. M. Kruse
1854
Application of Constant Current Potentiometry to Nonaqueous Titrations of Weak Acids
1857
Irving Shain and G . R. Svoboda
Determination of p-Phenylenedilithium by Potentiometric Titration with Cerium(IV) Nitrate Solution. .
1860
A . F. Clifford and R. R. Olsen
2,4,6-Tripyridyl-s-triazine as Reagent for Iron. Determination of Iron in Limestone, Silicates, and Refractories
1862
P. F. Collins, Harvey Diehl, and G. F. Smith
FOR: Glassblowing and
other
tasks obscured a
by
dazzling
yellow
flame
The selective f i l t e r i n g lenses in PARR Glassblowers' G o g gles block out the objection able y e l l o w glare always present in g l a s s w o r k i n g oper ations. They transmit o n l y a trace of y e l l o w light w i t h o u t seriously reducing the inten sity of red a n d other colors in the visible spectrum. A v a i l a b l e in l i g h t w e i g h t safety f r a m e s , also in a clip-on style, each complete w i t h case.
Zirconium Analysis by Production Control Quantometer
C. L. Easlerday
1 867
Amperometric Determination of Tin with Cupferron
1868
S. S. Y a m a m u r a , J. E. Rein, and G . L. Booman
lodometric Method for Determination of Persulfates
1 870
Nagi W a h b a , M . F. El Asmar, and M . M . El Sadr
Determination of Chlorine Dioxide in Treated Surface Waters
M . A . Post and W . A . Moore
1 872
Order from any Parr Dealer, or write direct for Spec. 4200.
Direct Karl Fischer Determination of Water in Vinyl Ethers
P A R R INSTRUMENT CO. MOLINE, ILLINOIS
Lucien Barnes, Jr., and M . S. Pawlak
Selected Triphenylmethane Dyes indicators in Glacial Acetic Acid O . W . Koiling and M c C . L. Smith
Circle No. 86 on Readers' Service Card 6 A
•
ANALYTICAL CHEMISTRY
as
1 875
Acid-Base 1876
