If the heating system you want hasn't been built yet... build it ! It'ssimple—with Lindberg Hevi-Duty building blocks of heat. These flex ible, low-cost elements can be as sembled in countless ways. They're perfect to heat piping systems where liquids must be kept at constant temperature. Or for spe cial lab requirements that don't justify a furnace. Or where there isn't a furnace to do the job. They have excellent capacity. High watt density. 1000° or 1200° C. Con trol them manually, or automatically. They're available from leading lab dealers in sizes, shapes, and lengths to fit your projects. Write for bulletin 50910, Lindberg Hevi-Duty, Watertown, Wis. 53094.
QUALITY at every turn in this
BIDDLE 6 - D I A L POTENTIOMETER
gold plated keys and binding posts, pre cision finished wiring and solder joints, the guard rings, the resistors. In fact, there is so much hand crafted care given to each Biddle Precision Instru ment, "it improves with age, just like a rare wine." Another plus in buying Biddle Precision Instruments is that you receive the attention of a company small enough to know you and large enough to serve you . . . and old enough to be called the "Home of the Ohm." Write for full line Bulletin 60-ββ—AC
J A M E S G. B I D D L E CO. Electrical and Speed Measuring Instruments
PLYMOUTH MEETING. PENNSYLVANIA 19462 Phone 215/645-9200
"See Laboratory Guide for all Products/Sales Offices" Circle No. 24 on Readers' Service Card
SODIUM BIPHENYL REAGENT For Rapid, Quantitative Determination of Bromine, Chlorine, Iodine and Fluorine in Organic Compounds. Sodium Biphenyl Reagent converts organic halogens to their sodium salts, which then may be measured by usual laboratory methods for halides. Conversion is quantitative on most organic compounds in 3 0 minutes. No special glassware or equipment required. Supplied as 0.6 normal solution in ethylene glycol dimethyl ether, Sodium Biphenyl is stable up t o one year under refrigeration. Avoid the difficult preparation of this reagent by purchasing one of the convenient sizes Write for our Sodium Biphenyl product bulletin. Specified Harleco I t e m No. 7590
4oz.-$10.00
16 oz.—$15.00 32 oz.-$20.00
Package of 12-15 m l . units
LINDBERG D I V I S I O N
O f
$12.00
HEVI•DUTY SOLA
B A S I C
I N D U S T R I E S
"See Laboratory Guide for all Products/Sales Offices" Circle No. 56 on Readers' Service Card
Harl&co®
MARTMAN-LEDDON COMPANY. INC. Both & Woodland Avenue Philadelphia 43. Pennsylvania. U.S.A.
Circle No. 44 on Readers' Service Card VOL. 3 8 , N O . 8, JULY 1 9 6 6
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