FOR THE BEST IN VACUUM PUMPS SELECT
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WELCH DUO-SEAL*
L.T. Hallett, Editor
ACK
OF AWARENESS of the
L applications
many
of microscopy and crystallography to chemistry is a hindrance not only to chemists but to the analytical, control, produc tion, and research operations in companies concerned with chemical analysis and physical properties of materials. So states Walter C. M c Crone of AValter C. McCrone As sociates, 501 E a s t 32nd St., Chicago 16, 111., in a recent communication to the editor. Versatility of this technique is shown by the successful handling of the following problems m a n y of which could have been done only by the microscopic and crystal l o g r a p h y approach: identification of 10μ inclusions in synthetic poly mer films, change in solubility of a drug after storage, development of a one minute stop and go analytical control method for purity of an in secticide, elucidation of mechanism of action of pour point depressants in lubricating oils, identification of particulate m a t t e r in settled dusts, stabilization of emulsions of a p h a r maceutical preparation, identifica tion of physical evidence for crimi nalistic purposes, and reason for unexpected variations in sensitivity of an explosive. D r . McCrone attributes lack of use of microscopic and crystallographic techniques to the lack of educational and training opportuni ties. Very few colleges have sub stantial courses in this field, p a r ticularly a t the undergraduate level. Most chemists are exposed t o microscopy and crystallography briefly, if a t all, in college. This leads to a dearth of qualified chemical microscopists and a lack of understanding on the p a r t of laboratory supervisory and m a n agerial personnel of their value. M a n y research directors first be come acquainted with the power of
Welch Pumps are best because : Every pump is triple tested. Specified performance guaran teed. Lowest cost per year of use. Highest vacuum of any mechanical pump. Quietest me chanical pump made. AVhen you buy a Duo-Seal Pump, you are buy ing a pump with a reputation. Over the years Duo-Seal pumps have built up this reputation for long-life dependability, quiet operation, long-term adherence to original specifications.
Rigid design requirements make these pumps quiet operating, long wearing; meticulous fac tory inspection methods make sure that every pump is perfect when it leaves the plant. Triple testing with McLeod gauges leaves no room for question on final performance.
For complete specifications, request our catolog.
THE WELCH SCIENTIFIC COMPANY ESTABLISHED 1880 1 5 1 5 S e d g w i c k St., Dept. A - l , Chicago 10,111., U.S.A. Manufacturers of Scientific Instruments and Laboratory Apparatus
DUO-SEAL PUMP OIL is a must to keep your Duo-Seal vac uum pumps operating at highest vacuum and efficiency. A chem ically-stable, low-vapor-pressure product, Duo-Seal Oil is produced according to the most exacting specifications. $0.90 qt. $2.65 gal.
and other Laboratory Ceramics Saxonburg laboratory ceramics are manufactured from highest grade zir conium silicate material. Quality is care fully controlled t h r o u g h o u t production, including tests on each lot in s t a n d a r d t u b e or induction furnace. All pieces are packed in cans or a l u m i n u m foil t o pre v e n t contamination. Immediate delivery available on s t a n d a r d sizes of boats, crucibles, ped estals, covers, inserts a n d sleeves.
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Circle No. 82 on Readers' Service Card VOL.
3 3 , N O . 3, MARCH 1 9 6 1
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