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ANALYTICAL
New 1 H.P. CUT-OFF MACHINE
Splash guard opened showing jet pipe for coolant; a companion jet is on the opposite side of the wheel.
A laboratory siie cutter with ample power for fast cutting of samples up to 1 " in diameter.
This cut-off machine is built with the usual Buehler emphasis on precision in both the construction of the machine itself and the work it performs. The con trols are arranged for the utmost convenience of the operator — a feature that contributes to speed and accuracy in cutting samples.
Complete view of cab inet showing storage bin for extra wheels and tools.
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The cutting wheel mounted directly on the ball bear ing motor shaft is free from side play or vibration and is cooled by a stream of coolant directed on both sides of the wheel under the guard. The cutting is done on the front of the wheel by using the long lever handle to raise the clamp base holding the sample to contact the wheel. This mechanism is bal anced so that pressure against the cutting wheel is under perfect control at all times by the operator. A metal splash guard, removed in the illustration, furnishes pro tection from spray. Overall dimensions are 24" χ 28" χ 50". Shipping weight, 575 lbs. THE BUEHLER LINE OF SPECIMEN PREPARATION EQUIPMENT INCLUDES . . . CUT-OFF MACHINES · SPECIMEN MOUNT PRESSES · POWER GRINDERS · EMERY PAPER GRIND ERS · HAND GRINDERS · BELT SURFACERS · POL ISHERS · POLISHING CLOTHS · POLISHING ABRASIVES
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METALLURGICAL APPARATUS H 5 WEST WACKER BRIVS, CHICAGO 1, ILL.
CHEMISTRY
An interesting and enlivening account of x-ray diffraction as an analytical tool was given by I. Fankuchen of the Brooklyn Polytechnic Institute. As a physicist, the speaker admitted his reluctance in saying that 90% of all x-ray meas urements are concerned with analytical problems of one sort or another. Although several excellent x-ray analysis instru ments are available in this country, in his opinion there is a dearth of good single crystal x-ray goniometers and the im ported versions are much better than ours. The speaker also described some of his work on microcameras and a twin crys tal spectrometer. The great need for an extensive revision of x-ray data was pointed out and the unusual value of the x-ray method as a means for determining molecular weights was emphasized. Some of the distinctive analytical applications of electron diffraction and electron microscopy were described by Κ. Η. Storks of the Bell Telephone Laboratories. Examples of the various techniques for specimen preparation were described, such as mulling powders in parlodion for dispersion and film casting on slides. An interesting case, illustrating the need for reference to alternative methods, was one in which x-ray examination had shown the presence of nickel whereas the electron diffraction pattern showed definitely that nickel ox ide was present. P. P. Debye, also of the Bell Telephone Laboratories, de scribed particle size determinations by light scattering, a technique which has been so useful in studying macromolecules. It has been possible to extend the technique to sys tems of molecular weight as low as that of sucrose. After describing the theory of light scattering and the special photometers required for the measurements, the speaker de fined the dissymmetry coefficient, obtainable by measuring the scattering intensity at 45° and 135° to the optic axis. He also discussed the interpretation of scattering data in terms of the behavior which is to be expected for spherical, rodshaped, and coiled molecules, respectively. Instruments, techniques, and applications for radioactive isotopes were described by B. Schloss of the Nucleonic Sales Co. An excellent summary of the fundamental concepts and techniques of nuclear physics was followed by demon strations with scaling equipment. Lack of time unfortu nately hampered the speaker, but still permitted the audience to gain a clear, systematic picture of this important field. Informational Advertising We wish to acknowledge the important aid which many in strument manufacturers and dealers are giving analysts and the entire field of analytical chemistry, by supplementing their advertising with literature references and helpful hints. We hereby assume the calculated risk of singling out one of these and know with certainty that we shall receive many reproofs for neglecting others who have been equally helpful. Walter Burfischer of the AVilkens-Anderson Co., I l l North Canal St., Chicago, has issued another set of "Curves and References"—a compilation of literature abstracts, helpful hints, and breezy comments on spectrophotometric deter minations. They are classified according to the type of analysis: steel, water analysis, vitamins, clinical, etc. A number of publications are also listed, some of them free and others at regular publishers' rates. These references deal primarily with methods adaptable to the Coleman and Klett instruments, but are valuable to anyone concerned with opti cal methods of analysis. We wonder if all advertising managers are aware of the good will which this class of service engenders among the scientific public.
