Tired of Shaking Test Tubes by Hand?
REPORT
New continuous-duty rotary agitator holds up t o 12 test tubes or small vessels t o f r e e you f o r other work in the lab. The SPÊNNERETTE Typical applications: • effecting small-scale extractions, and mixing of solutions, emulsions, dispersions or colloids. • culturing organisms, viruses, tissue cultures or cells. • blood analysis a n d small-scale dialysis. Designed for optimum variation in rate of mixing or agitation by virtue of vertical-to-horizontal tilt angle of platform plus four rotating speeds (15, 30, 45 and 80 rpm). Affords smooth, quiet and maintenance-free service and can operate anywhere— on a work table or mounted on a wall. Interchangeable platforms available t o hold small bottles and small Erlenmeyer flasks. Write for Bulletin ST-Al
NEW BRUNSWICK SCIENTIFIC CO. PRECISION
LABORATORY
APPARATUS
P.O. BOX 6 0 6 · NEW B R U N S W I C K . N . J . For further information, circle number 30 A-1 on Readers' Service Card, page 101 A
FLUORESCENCEl
FLUORESCENCE & TRANSMITTANCE "more discriminating or Spectrophotometric
than
FLUORESCENCE & REFLECTANCE Colorimetric assay..."
FAR RAND.
Ultraviolet Visible Infrared
SPECTROFLUOROMETERS "Spectrofluorometric assay has several distinct advantages over other physical methods using light absorption. Fluorescent methods, where applicable, yield a sensitivity at least two orders of magnitude greater than Spectrophotometry." Bulletin No. 820 describes manual — automatic recording —and oscilloscope models. . D •» .. Λ7 ΟΟΛ Bulletin No. 820 on request.
FARRAND OPTICAL CO., Inc. BRONX
BLVD. & EAST 2 3 8 t h STREET, N E WY O R K 7 0 , Ν.Υ. Engineering * Research * Development * Design * Manufacture Precision Optics, Electronic one! Scientific Instruments
Figure 7. Micrograph of sectioned and etched lithium fluoride crystals; ( A ) surface abraded; (B) quenched in water from 120° C ; ( C ) curved and reflattened. Dislocation sites are shown by the etch pits and extend further into the crystal for treatment ( C ) than f o r ( A ) or ( B ) . The scale of distance is in thousandths of an inch
water vapor. However, a tenfold increase in intensity is possible for elements around aluminum. Incidentally, the back of the tube should have a window also to allow unabsorbed radiation to emerge, so it will n o t increase t h e general background level near the characteristic line. X - r a y spectrochemical analysis h a s come a long way in t h e past 10 years. B u t b y comparison, further advancement should be even greater, especially for routine analysis, as completely automatic instruments replace the manually operated spectrometers. As evidence of interest in t h e method, papers on x ray spectroscopy now exceed in n u m ber t h e papers on x-ray diffraction a t m a n y of t h e scientific meetings. T h e number of new workers interested in the x-ray method seems t o be almost doubling each year, a n d if this continues, x-ray spectroscopy should soon be on an equal competitive basis with wet chemistry a n d emission spectroscopy.
For further Information, circle number 30 A-2 on Readers' Service Card, page 101 A 3 0
A
·
ANALYTICAL
CHEMISTRY
For further information, circle number 31 A on Readers' Service Card, page 101 A
