26 A
ANALYTICAL
Laboratory
INSTRUMENTATION
Equipment
NEWS
OF THE MONTH
PORTABLE ^ ^
I
pH METERS
*T
DESK TYPE METALLOGRAPH ( A O M o d e l 2 4 0 0 ) The last w o r d In ease, looks, accuracy! AH controls o p e r a t e f r o m sitting posi tion. Features Include automatic focusing, instantly c h a n g e a b l e magnification, easy g r a i n - s i l e meas urement, built-in p h o t o g r a p h i c eyepieces. Will's 1 7 7 9 I T . Request Bulletin M I 6 V - 9 5 0 . Beckman p o p u l a r M o d e l N-2 meter is fwlly port a b l e , r u g g e d l y built f o r outdoor w o r k . Hinged cover contains accessories. 1 6 1 8 3 T $ 195
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Beckman M o d e l N - I pH Meter (not shown) has single case with attached carrying handle. 1 6 1 82T $180 Send f o r complete
BECKMAN PYREX CELLS low-PRICED cells o f " P y r e x " Brand glass, f o r M o d e l s DU a n d Β Beckman Spectrophotometers. For work in the 3 2 0 to lOOOmu r a n g e . W i t h Pyrex cover. 2 4 3 5 6 T $6
VACUUM OVEN For small labs. O v e n o"diam-, 8/3"deep. Range from room temp. to 125°C. Thermostat control to ± 0 . 2 5 ° C . For 115 V / A C . 20871 $105
literature.
FLEXIBLE BOTTLES New 1 and 2 gallon sizes. T o u g h , i n e r t , almost unbreakable; much safer f o r trans porting a n d storing liquids. Supplied with plastic screw caps. 3789T 1-gal., e a . $ 1 2 ; 2 - g a l . ea. $ 1 8 6 Smaller sizes—1 oz. to 3 2 oz. Ask f o r prices.
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'MULTI-RAY' LAMP
MUFFLE FURNACE
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(Temco M o d e l RCE) O n e of six sires a v a i l a b l e . O p e r a t e s at a n y temperature from 3 5 0 ° to 1850°F. Solid aluminum, with remov a b l e heating chamber 4 3 / 4 " w i d e , 4 ' Λ " high, 6"deep.For]15V/AC. 14801 $85
It's F a s t e r . . . Easier to order from WILL
Your inquiry gets instant, cour teous attention — a n d is han d l e d under personal supervision o f an individual withyears o f e x perience in l a b o r a t o r y supply. FIVE b i g warehouses, all linked b y t e l e t y p e , give y o u fast, f l e x i b l e service to meet unusual needs.
Four Interchangeable tubes p r o v i d e short w a v e UV f o r disinfec tion, l o n g w a v e UV f o r fluorescence, north sky light f o r color match ing, a n d a white light of strong intensity. 115 V, 0 0 - c y / A C . 17401 $32
For more data on any of these items— PHONE-WRITE-WIRE-TELETYPE your nearest WILL office-warehouse: WIll
CHEMISTRY
CORPORATION
Rochester 3, Ν . Y.
W I l l CORPORATION
Mew York 12, Ν. Υ.
W I l l CORPORATION of Md., Baltimore 1, M d . SOUTHERN SCIENTIFIC CO., INC.. Atlanta 1, G a . BUFFALO APPARATUS CORP.. Buffalo 5, Ν. Υ
control heavy duty equipment. The classical example has been thermostatic controls, in which the vacuum tube as sembly provided an essentially "no cur rent" regulation of sensibly heavy heat ing currents. Industrial practice has required Icftig-term and trouble-free service, and in this sense, vacuum tube regulators, although vastly superior to the older mechanical arrangements, have shown residual deflects primarily due to a variable and unpredictable cathode and heater life. Another defect was the limited degree to which these relays could be adapted to a wide range of signal input resistance. The new development is the cold cathode pilot relay made by the Haledy Electronics Co. This relay uses the Type TT-1 cold cathode triode which has no heater and has a cathode of practically unlimited life. No trans former is required and the circuitry is correspondingly simplified. The relay will operate over any input resistance from a dead short to 10 megohms and with leads from the control device of almost any desired length. The input control current has a maximum value of 2 microamperes. The output of the cold cathode triode directly operates a S.P.D.T. relay having a contact capac ity of 5 Α., at 115 volts a.c. Under these conditions, the maximum gain of the system could be rated at 2,500,000. For circumstances under which heavier power must be controlled, a Haledy mer cury contactor is available which has a rating of 30 amperes, at 115 volts a.c, or 20 amperes at 220 volts a.c. An additional advantage of the cold cathode relay is its instantaneous ac tion, because no preliminary warm-up or stabilization period is required. The normal output of the cold cathode triode in this control device is 15 ma. through a load of 2500 ohms. The specifications for the standard model SS cold cathode electronic pilot relay are summarized as follows: input resistivity range, 0 ohm to 10 meg ohms; maximum input current, 2 micro amperes; maximum input lead length, unlimited ; power requirements, 2 watts, 115 volts, 60 cycles, one side grounded; relay, S.P.S.T. contacts rated at 5 am peres at 115 volts 60-cycle; electronic tube; one TT-1 cold cathode triode; case, 18-gage drawn steel, wrinkle gray (Continued ore page £8 A )
