the EDITOR'S column L.T.Hallett, Editor
υ
SE OF THE infrared absorption spectrophotometer for inor ganic and mineralogical examina tions represents a considerable de parture from its usual application in structural studies and analysis in organic chemistry. During the past three years, for example, the Kennecott Research Center, Salt Lake City, Utah, has prepared 4000 infrared curves of standard minerals, rocks, and other inorganic materials. Results of these studies were reported by R. J. P. Lyon, W. M. Tuddenham, and C. S. Thompson at the Rocky Mountain Minerals Conference. This meeting was sponsored by the Utah Section of AIME. In their paper, "Quantitative Mineralogy in 30 Minutes," the au thors said that the infrared tech nique can yield both qualitative and quantitative results in mineralogical examinations. The technique has the added advantage of produc ing reproducible results rapidly. Technicians can do this work. The authors use a portion of the assay pulp sample (at minus 200 mesh) which has been prepared for wet chemical analysis. In addition to eliminating the need for prepar ing a second sample, the pétrographie results from the infrared studies are obtained on the same sample used for the wet analysis. Unlike x-ray diffraction techniques, which are concerned with preferred orientation problems, infrared absorption curves are not modified by grain size as the samples are ground to —1 micron. This is a particular advantage in pétrographie examinations of finegrained and even cryptocrystalline rocks. The authors have even obtained excellent spectra from samples that would be considered amorphous by x-ray diffraction.
RELIABLE
• FAST-ACCURATE
• ALL-AROUND
Welch TRIPLE-BEAM BALANCE With StaUtUu Capacity 111 grams
Steel And
(201 grams using auxiliary weight)
SENSITIVE TO 0.01 g. or less
Rapid Weighing PERFORMANCETESTED
Good Sensitivity High Stability CorrosionResistant
^r
NO.4030
4030. 4031. 4030C.
TRIPLE-BEAM B A L A N C E , H I G H Form. Each $27.50 A U X I L I A R Y WEIGHT. Each $1.50 PLASTIC COVER For No. 4030. Each $1.60
W. M. WELCH SCIENTIFIC COMPANY DIVISION OF WELCH MANUFACTURING COMPANY
ΕSTABLISHED 188 0 1515 SEDGWICK STREET, DEPT. A - 1 , C H I C A G O 10, ILLINOIS, U.S.A. Manufacturers of Scientific Instruments and Laboratory Apparatus
Provide instant relief with . . . EMERGENCY EYE and FACE WASH FOUNTAINS
HAWS
Eye a n d face hazards
a r e i n e v i t a b l e in
i n d u s t r y . . . so take positive steps to reduce the extent of injury and minimize
insurance
HAWS Emergency Eye and Face Wash flood
contaminated
areas with
claims.
Fountains
water — instantly
ridding face and eyes of caustics, chemicals and dan gerous particles. This instant relief may well pre vent permanent damage - bridging the gap until medical aid arrives. Install extra safety —HAWS Emergency Fountains and Drench Showers. Write today for detailed infor mation on the complete HAWS line of emergency facilities. HAWS DRINKING FAUCET COMPANY, 1443 Fourth Street, Berkeley 10, Calif.
Model 8 9 3 3 : Face spray ring acts simultaneously with eye-wash, sending controlled streams of water from specially de signed twin fountain heads. Circle No. 115 on Readers' Service Card
VOL. 3 1 , NO. 3, MARCH 1959 ·
55 A
