30 A
ANALYTICAL
CHEMISTRY
STOP WATCH The National HEADQUARTERS VACUUM OVEN Range 30 to 1 2 5 ° C Sensitivity 1 / 4 ° C.
W e carry a large stock of split-second down
to
stopwatches, 1/100
calibration, for
second
laboratory
and industrial use. Routine grade and scientific accu racy models range in price from $16.50 upward.
LABORATORY GRADE . . $2950 each Timers tabulated below are fine Swiss make, precisely calibrated, with 7-jewel temperature compensated movements, sturdy action and nickel-chrome cases. Please specify second or third choice to assure prompt delivery. A. B. C. D. E.
I I I I
Stop-start from crown. Time-out side lever for fly-back. Stop-start from side lever; time-out and fly-back from crown. Inner dial graduated in 1/100 min. Inner dial with 60 piece per hour time study graduation. Calibration 1/5 sec. 1 / 5 sec. 1/100 min. 1/10 sec. 1/5 sec. 1/100 min. 1/10 sec. 1/5 sec. 1/5 sec. 1/100 min. 1/10 sec.
Model 705 706 707 710 805 807 810 905 906 908 910
Dial 1 min. 1 min. 1 min. 30 sec. 1 min. 1 min. 30 sec. 1 min. 1 min. 1 min. 30 sec.
Registers To: 30 min. 30 min. 30 min. 15 min. 30 min. 30 min. 15 min. 30 min. 30 min. 30 min. 15 min.
*Other Features A A, E A, E A A, B Α , Β, Ε A, B C C, D C C
Cat. No. 9103
I I I I
SPECIAL OFFERING —1/10 SEC. ELGIN Limited quantity available of Elgin stopwatches obtained from war surplus, slightly used but top condition. Ten second dial, in 1 / 1 0 second divisions, with 5 minute totalizer dial. Seven-jewel movement. Stop, start, return to zero by pressing crown. Original ff-a « J J Q value about $30.00. Each I f
ROUTINE GRADE TIMER BACK
AGAIN
Highly dependable, accurate for diverse testing or control work — a superb value long absent from the market. Seven-jewel compen sated movement, nickelchrome case, unbreak able crystal. Time-out action for interrupted timing. Stop, start from crown. Return to zero by side button. 97 7 Sixty second dial, in 1 / 5 seconds, and 30 minute totalizer d i a l . . . 16.50 972 Thirty minute dial, in 1 / 1 0 seconds, and 1 5 minute totalizer d i a l . . . 18.50
Ask
for timer data
IEC-5
TECHNICAL SERVICE
ANDREW
1 1 1 East D e l a w a r e P l a c e , C h i c a g o 1 1 , III.
The National Vacuum Oven was designed to meet the demand for an inexpensive but efficient vacuum oven for general laboratory use. I t is an ideal unit for making moisture determinations and dehydrations, drying materials wet with inflammable sol vents, or subject to scorching at higher temperatures. Low cost, sturdy construction, utility, efficiency and appearance are features which will make this oven an im portant addition to any laboratory. SPECIFICATIONS Construction — Outside of oven is made of sheet iron with baked artmetal finish. Oven chamber is made of nickel plated copper and surrounded by a thermostatically con trolled air bath. Fittings are chrome plated. Dimensions — Outside dimensions are %}/
