30A
ANALYTICAL
CHEMISTRY
NEW LABORATORY MILL WITH MICROMETER SETTING
COLLECTIVE NUMERICAL PATENT INDEX
PREPARES LARGE NUMBER AND VARIETY OF SAMPLES
to Volumes 3 1 - 4 0 of
CHEMICAL ABSTRACTS • Contains more than 143,000 entries, classified by coun
Classification by patent number is an enormous timesaver.
tries in numerical order.
"Labconco" Heavy Duty Laboratory Mill Base plate: 12%" x 17%"ί height: 19". With this new laboratory mill by "Labconco," the chemist can prepare a sample in any size, from powder-fine to coarse grind by changing the micrometer adjustment. Although essentially of the "burr" type, this new mill has a unique "cutting" rather than a "grinding" action. This feature does away with the limita tions and inconveniences of the burr type mill, but retains the speed, simplicity and ease of operation. Witii the new "Labconco" mill, there are no screens to change, or knives to sharpen. There is no steel-to-steel friction, and there is no cleaning problem, because special steel-and-leather wipers continuously sweep the grinding chamber clean. There is less "separation" of the sample, more homogeneity; slower speed minimizes dust; sample cannot "build up" on knife blades. Oily products such as meat scrap, soy beans and flax seed can be satisfactorily prepared, as well as products containing up to 17% moisture. Finer grinds, of course, are possible on drier samples. The one-horsepower motor and rugged modern design make this min well-suited for heavy use in any laboratory. Write today for full details, prices on two models, and list of users.
• Index references give vol ume, page and location of patent abstract in C H E M I C A L ABSTRACTS.
PRICE $6.50 POSTPAID Send
orders
and inquiries
to:
Special Publications Dept.
American Chemical Society 1155 Sixteenth St., N.W., Washington 6, D. C.
LABORATORY CONSTRUCTION COMPANY 1115 HOLMES S T .
ι Cloth bound, 182 pages, 71/2' χ 10" overall, 8 col umns of listings per page covering all patents ab stracted i n C H E M I C A L A B STRACTS from 1 9 3 7 - 4 6 , inclusive.
KANSAS CITY, MISSOURI
S&S AMERICA'S
for purity
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and
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FILTER
PAPERS
RELATIVE VALUES O F RETENTION OF S * S ANALYTICAL FILTER PAPERS A i M r w P«p#r»
Other Grodm
S & S Hardened Filter Papers— from the fastest to 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 gela tinous ppts. from sodium hydroxide media. The grades 404 and 497 have found excellent application in the production 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, injecfion fluids, etc. The ash-free No. 507 possesses outstand ing 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
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