VOLUME
2 4, N O . 9, S E P T E M B E R
S
1952
&
43 A
S
for purity and
uniformity
AMERICA'S FINEST ANALYTICAL FILTER PAPERS RELATIVE VALUES OF RETENTION OF S & S A N A L Y T I C A L FILTER PAPERS
S & S Hardened Filter Papers— from t h e fastest t o t h e m o s t retentive The very rapid hardened grades S & S No. 410 and 589-1 H are particularly suitable for the reprecipitation and filtration of the metallic hydroxides and of bulky gelati nous ppts. from sodium hydroxide media. The grades 404 and 497 have found excellent application in the pro duction of S & S tear-proof folded filters. No. 402 is being used extensively in soil analyses. No. 576 is the standard grade for the filtration of serum, injection fluids, etc. The ash-free No. 507 possesses outstanding qualities in certain problems of chromatography. Write for samples and latest catalog No. 70-A.
SCHLEICHER & SCHUELL CO. 515 Washington St., Keene, New Hampshire ALWAYS
INSIST
ON S & S AMERICAN
FILTER
PAPERS
CHEMICALS Selected Reagents Stand ardized for PARR Bombs and Calorimeters
Parr Sodium Peroxide, calorific grade, for all peroxide bomb tests. Minimum assay, 96.0% Νβ2θ2· Negli gible sulfur. Potassium Perehlorafe, accelerator for peroxide bomb tests, dried and screened through 100 mesh. Negligible sulfur. Benzoic Acid, thermal value standard for oxygen bomb calorimeters. Also, addition agent for peroxide bomb tests. Comes in powder or pellet form.
PARR EST.
1899
•
Barium Chloride, sized crystals, 20 to 30 mesh for rapid sulfur determinations with PARR Turbidimeter. Gelatin Capsules, for holding liquid samples in combustion bombs. Heat of combustion and sulfur content reported on label.
• Order from your PARR Dealer or write to the factory for details and standard package prices.
INSTRUMENT CO.. MOLINE, ILLINOIS MAKERS OF CALORIMETERS AND PRESSURE REACTION EQUIPMENT
