20 A
ANALYTICAL
Accurate Microscopic Observations
UNDER HEAT with
REICHERT
Since
1875
O R I G I N A L
KOFLER
MICRO HEATING STAGES
Original Kofler Micro Heating Stage mounted on a Reichert Microscope
OBSERVE Decomposition . . . Crystal W a t e r . . . G r o w t h . . . Discoloration . . . S u b l i m a t i o n . . . Dissolving Phenomena . . . Volatility DETERMINE M e l t i n g P o i n t s . . . Eutectic T e m p e r a t u r e s . . . Molecular Weights IDENTIFY O r g a n i c S u b s t a n c e s . . . Compounds EXAMINE P o l y m o r p h i c Substances The Original KOFLER Micro Heating Stage is easily mounted on any microscope with a heat-resisting stage. A specially designed Reichert Microscope with polarizer and analyzer is available for use with this stage. The KOFLER STAGE consists of a heating chamber, two graduated thermometers —|—20 to -}-230°C and -)-90 to -j-340°C, rheostat controlled heating element, glass baffle, cooling block, specimen shifter and glass cover plate.
Available
for prompt
delivery
FOR DETAILED INFORMATION WRITE FOR CATALOG A H
National Representatives:
WM. J. HACKER & CO., Inc. 82 Beaver St., New York 5, N. Y.
CHEMISTRY
INSTRUMENTATION Photoelectric
Spectropolarimeter
A photoelectric spectropolarimeter has been announced by 0. C. Rudolph and Sons of Caldwell, N. J. O. C. Rudolph has been associated with the use and design of high precision polarimeters for many years and we assume that he would not approach the problem with the blind enthusiasm and misplaced optimism of the electronics expert. Evidently, he has succeeded handsomely, because rotation with a probable error of from 0.004 to 0.001 angular degree has now been achieved. The instrument combines a Beckman spectrophotometer, for . the isolation of monochromatic light, with a precision polarimeter. A choice of photomultiplier tubes permits measurement in the visible and ultraviolet. The ease with which rotatory dispersion can be determined by this means would seem to furnish the analyst with another very useful and important tool. One of the outstanding treatises on physical measurements devotes many pages to the proof that photoelectric measurements in polarimetry are ill advised and more or less impossible. Some of the circuitry which has been employed in the past would assure that indictment in advance. We are pleased to note that it has been done successfully and with a degree of precision that seems to be at least twice as good as some of the best visual instruments. Once more we would like to express the hope that someone will re-examine the magneto-optic effect and provide the analyst with a fast and precise means for measuring the Verdet constant without a Avhole roomful of equipment. Its advantage over ordinary optical rotation resides in the fact that it is a universal phenomenon, exhibited by all substances and in every state (Continued on page 22 A)
TAYLOR COMPARATORS assure
speedy pH, Chlorine, Phosphate determinations
TAYLOR GUARANTEED COLOR STANDARDS ASSURE ACCURACY! Speed is assured because Taylor Comparators are so easy to use. No heavy, bulky equipment. No fragile single color standards to handle, all slides for any one determination are mounted in a sturdy plastic base. And, you get everything you need with your Taylor Comparator . . . slide, base, reagent and accessories. Carrying cases also available a t slight extra cost. Continuing accuracy is assured because all Taylor liquid color standards carry an unlimited guarantee against fading, thus no mechanical inaccuracy is possible. Taylor Comparators are available for combinations of pH, chlorine and phosphate, complete water analysis and many more determinations. Many slides can be used on one base. SEE Y O U R DEALER FOR TAYLOR SETS
FREE REFERENCE BOOK tells theory a n d a p p l i c a t i o n o f pH a n d chlorine control in 3 4 basic industrial processes. Also d e scribes and illustrates comp l e t e Taylor line. W r i t e f o r your copy t o d a y !
W. A. TAYLORS and CO. 7302 YORK RD. · BALTIMCRE-4, MD.
