ANALYTICAL
22 A
plate to secure the blocks. These screws are provided with large knurled heads for finger-tight adjustment. For more permanent setups Allen cap screws are recommended. All blocks are dimensioned to hold motors, etc., exactly 1.5 inches off base. The blocks are precision-bored to accept the flange mounting of standard commercial units such as Kearfott motors, Bendix Autosyn, Fairchild potentiometers, etc. The gear clamps are ingeniously devised to eliminate the errors of the usual shaft set screw. An example is seen between the end of the motor shaft and the mounting block. A small tapered and slit collet fits into a tapered recess in the gear. A large cap screw threads onto the hub of the gear and as this is drawn up (finger-tight) the collet is shrunk tightly and concentrically to the shaft.
Kleet . . . .
Photometers Kleet
CHEMISTRY
Summerson Photoelectric Glass Cell
Colorimeter No. 900-3
The Klett Flourimeter
No. 2070
Figure 2
Designed for the rapid and accurate d e t e r m i n a t i o n of thiamin, riboflavin, and other substances which fluoresce in solution. The sensitivity and sta bility are such t h a t it has been found particu larly useful in determining very small a m o u n t s of these substances.
Servomechanisms, Inc., furnishes a complete kit containing a liberal assortment of these components and additional items can be ordered from an extensive stock. The company is also prepared to supply packaged servo units and laboratory servo testing apparatus and is engaged in development work in this field. Information regarding these products can be obtained from the Control Systems Company, G.P.O. Box 334, New York, Ν . Υ. We have often attempted the solution of an instrument problem by wholly electronic means, even where it was evident that an intermediate mechanical element would be preferable. No doubt many other's have done the same in an effort to avoid the delay and expense required by precise machine work. The servo development apparatus should be very useful in the research laboratory for this and many other problems.
KLETT SCIENTIFIC PRODUCTS
Book on Electronic Instruments ~We have made frequent reference to the Μ.Ι.Τ. Radiation Laboratory Series of monographs published by McGraw-Hill. These are appearing now in rapid succession and we wish to record our particular enthusiasm for Volume 21, on electronic instruments, by Greenwood, Holdam, and-Macrae. More than 700 pages deal with five general topics: Part I, Elec tronic Analog Computers; Part I I , Instrument Servomecha nisms; Part I I I , Voltage and Current Regulators; Part IV, Pulse Test Equipment; Part V, Design and Construction of Electronic Apparatus. With the possible exception of Part IV, there is hardly a page in this stimulating and authoritative work which does not hold some promise and utility for solving the instrument problems of the analyst.
ELECTROPHORESIS APPARATUS · BIO-COLORIMETERS G L A S S ABSORPTION CELLS · COLORIMETER NEPHELOMETERS · G L A S S STANDARDS · KLETT REAGENTS
Klett
Manufacturing
Co.
179 E A S T 8 7 T H S T R E E T , N E W Y O R K , Ν . Υ.
