20 A A N A L Y T I C A L C H E M I S T R Y

A.H.T. CO. SPECIFICATION

K O F L E R M I C R O H O T S T A G E For determining corrected micro melt ing points and for general microchemicai

procedures on the microscope stage

KOFLER MICRO HOT STAGE (Micro Melting Point Apparatus), A.H.T. Co. Specification, electrically heated and with stage calibrated thermometers.

For determining corrected micro melting points by means of a microscope with samples as small as a single crystal, permitting continuous observation of changes in the sample before, during and after melting.

Useful also for general micro-preparative work, sublima­tions, measurements of refractive indices at elevated tem­peratures, fusions, heating under controlled conditions, etc., and phvsicochemical studies. See Ludwig Kofier, Mikrochemie,'Vol. XV (1934), V- %Α%; and L. Kofier and A. Kofier, "Mikro-Methoden zur Kennzeichnung Organischer Stojfe uni Stoffgemische" (Innsbruck, 1948).

For temperatures up to 350 °C, with an accuracy of ± 0 . 5 °C in the range to 200 °C and of ±1 .0°C in higher range. Can be used with transmitted, reflected or polarized light on any compound microscope providing magnifica­tions from 50 to 100 X with objective having working distance of 6 mm or more, and preferably with a metal stage.

The apparatus consists essentially of an insulated,

chromium plated metal stage, 90 mm diameter X 20 mm high, heated by an embedded Nichrome unit, and with a central light well fitted with a condensing lens system. A threaded post takes either a fork for the micro slide or various sublimation blocks. A variable transformer, with stop to limit output to approximately 80 volts and dial usable only over range from 0 to 80 in single divisions, permits exact reproduction of settings.

The two thermometers, ranges +30 to 230°C and +60 to 350 °C, respectively, have been calibrated on the indi­vidual Hot Stage with which they are to be used. A set of eight stable test reagents is included with each outfit. They are convenient, not only in acquainting the user with manipulation of the instrument, but also for the prepara­tion of a calibration chart for the transformer settings.

6886-A.

6887-A.

Micro Hot Stage, Kofler, as above described, complete assembly as shown in illustration, i.e., Hot Stage A with glass cover, two cali­brated thermometers M, cooling block H, Fischer sublimation blocks Ja and ,1b, glass baffle D, three sublimation dishes K, Kofler-Dernbach vacuum sublimation chamber E, fork lifter L, twenty-four micro slides P, set of test reagents T, and variable transformer but without microscope; in case, with detailed directions for use. For 115 volts, 50 or 60 cycles, single phase a.c. only. . . . 236.00

Ditto, Hot Stage A, only, with two calibrated thermometers M, cooling block H, glass baffle D and variable transformer, but without case or other accessories 164.50

CERTIFIED REFRACTIVE INDEX POWDERS, Kofier. A set of glass powders and minerals of accurately determined average refractive index, in intervals of approximately 0.01, for the determination of the refractive indices of fusions of inorganic or organic substances, or of liquids, in the range of 1.3400 to 1.6877, incl. For example, fusions prepared on the Kofler Hot Stage are tested by the well-known "Becke-Line" method in accordance with procedures developed by Dr. L. Kofler and his co-workers. 8606. Certified Refractive Index Powders, Kofler, as above described, range 1.3400 to 1.6877, set of twenty-four powders, each in glass tube

containing sufficient for 200 tests, complete in wooden case with red glass filter and detailed directions for use 26.50

More detailed information sent upon request.

ARTHUR H. THOMAS COMPANY R E T A I L — W H O L E S A L E — E X P O R T

LABORATORY APPARATUS AND REAGENTS WEST WASHINGTON SQUARE, PHILADELPHIA 5, PA., U.S.A.

Cable Address "Balance," Philadelphia

6886-A.

8606.