New ProductsThe information reported hiere is obtainted fromn

mnanufacturers a11(1 fromn othler sources conisideredto be r-eliaible. Neitiher Science nior the writer as-slimties respaonsi/bilitr for tlhe accumracv of the in-formation. A coupon foa use in mailing iniquir iesconcerninsg thle items listed is inclinided in the postcardl i sert. Circle the d(lepa tment number of thleitemix ini which a1oim are initer-ested onz this cotupon2.

* RELAYS are hermetically sealed mer-cury types salid to be capable of opera-tion at temperatures as high as 1200°F.Sliding contacts are used to avoid con-tact bounce. The relays are filled withdielectric gas of high arc-quenchingvalue. (Sorrels-Johnson Corporation.Dept. Sci627. 363 Rantoul St., Beverly.Mass.)

CLEANEST CLEANEST CLEANEST CLEANEST CLEANEST CLEANEST CLEAtIEST ANEST CLEANEST CLEANEST CLEANEST C

YHE ST CLEANEST CLEANEST CLEANEST CLECLE z T CLEANEST CLEANEST CLEANEST CLEAt;T CLEANESTLt7CANi E FlAST CLEANEST CLEANEST CLECLEANEST CLE - T CLEANEST CLEAt]EST_CLEANEST CLEANEST C)T CLEANES * CLEANEST CLECLEANEST CL CLEANEST CLEAt'T CLEANEST CLEANE slo- LANEST CLEANEST CLEiEST ClEANEST CLEANEST CLE.A EANEST CCLEANEST CLEANEST CLEA' T CLEAt;T CLEANEST CLEANEST CL m A .EST CLEIEST CLEANEST CLEANEST CL EANEST CCLEANEST CLEANEST CLEANEST CLEANI ,LI T CLEANEST CLEAt:-ST CLEANEST r 5NEST CLEANEST CLCLEAN NEST CLEAt!EST CI - 8LEANEST CiT CLE - ANEST CLECLEANE .NEST CLE

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Sold by All Leading Laboratory, Hospital and Sur- Meets Higheitgical Supply Dealers in the United States as well Government Specificationsas inCANADA . ENGLAND . SWITZERLAND . BELGIUM . NETHERLANDS . MEXICOVENEZUELA . PERU . BRAZIL . PANAMA . PUERTO RICO . HAWAII and

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* PROPORTIONING PIPETTES use a peri-staltic pump to dispense equal aliquotsof liquid. One nmodel of the device per-mits dial selection for automatic de-livery of up to 20 multiples of a fixedaliquot per operation. A second modeltransfers integral multiples of the ali-quot until stopped by the operator whenthe required memiiber appears on acounter. Nominal volume is 0.3 ml/rev.An alternative flexible tube for 0.2ml/rev is available. Deviation of totalvolulmle delivered by a number of revo-lutions is said to be less than 1 per-cent of the nmean volume per singlerevolution. (Baird & Tatlock Ltd.,Dept. Sci623. Chadwell Heath, Essex,England)

in coal and coke. according to ASTMmethod D271-48, is aided by apparatusthat controls automatically the rate atwhich the sample crucible is loweredand the length of time it remains in the

SCIENCE, VOL. 132

* KELVIN BRIDGE measures resistancefrom 10 ,uohm to 100 ohm. Test leadsmore than 100 ft long may be em-ployed with accuracy +0.25 percentabove 100 M,ohnm and ±+ 1 ohm below100 ,uohm. Test leads of any lengthare available with either C-clamp orspring-clamp terminations. (ShallcrossManufacturing Co., Dept. Sci626,Selma, N.C.)

* GAS DETECTOR is a portable instrumentwith probe-type detector connected byup to 100 ft of cable. Calibration is inpercentage of lower explosion limit ofdesired gas. An adjustable meter tripprovides buzzer alarm actuation. Anadjustable current meter allows approx-imate classification of gas constituentsin many gas mixtures. A battery andcharger are built in and the instrumentmay also be operated from a 110-volta-c source. (Houston Instrument Corp..Dept. Sci628, P.O. Box 22234, Houston27, Tex.)

* ADMITTANCE BRIDGE for the range 30to 300 Mcy/sec uses a thermistor ele-meirt in a servo feedback system asconductance standard. Accuracy is saidto be ± 2 percent over the entire fre-quency range. Capacitance range is+40 pf and conductance range is 0 to50 mmho. Voltage applied to the com-ponent under test is usually less than50 mv. Signal sources and detectorsare separately available. (Marconi In-struments, Dept. Sci625 l111 CedarLane, Englewood. N.J.)

* RANDOM-SIGNAL CORRELATOR. imiay beused to m.easure the normalized cross

correlation between two signals, eitherrandom or periodic. Frequency range is2 cy to 250 kcy/ sec. Input voltagerange is 20 ImyV to 2 v r.m.s., and gain iscontinuously adjustable from I to 1 00in each channel. Accuracy is said to

be 1 percent. An output selector per-nits selection of either of the two

signal channels or of the correlatedsignal. After the two channels havebeen equalized, positive or negative cor-relation cain be read directly on an

r.m.s. voltmeter. (Flow Corp., Dept.Sci634, 85 Mystic St.. Arlington. Mass.)

* ALIPHATIC ACIDS, their nmethyl esters,alcohols, and amines from C.; to C, are

available with purity said to be 99.5percent as judged from vapor-phasechromatograimis. Purification is effectedbv vacuunm fractionation. (Lachet Bio-chemical Co., Dept. Sci640, 2202 W.107th P1., Chicago 43, Ill.)

* VOLATILE MATTER DETERMINATION

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furnace. Three dials allow selectionfrom a variety of rates of descent andheating times. Two samples are accom-modated by the apparatus at one time.(Laboratory Equipment Corp., Dept.Sci642, P.O. Box 151, St. Joseph,Mich.)

* THIN SECTIONING MACHINE CUtSdentive sections as thin as 35 ,u andcrystal sections as thin as 0.005 to 0.10in. Sections may be cut from specimenblocks 3/4 by 1½/2 by 3 in. in less than5 minutes. Sections are said to be pro-duced with finished surfaces ready foruse in routine examinations withoutpolishing. (Will Corporation, Dept.Sci 644, P.O. Box 3927, Brighton Sta-tion, Rochester 10, N.Y.)

* ADJUSTABLE-LEAK VALVE consists of avacuum-valve body containing a sealedstem actuated by a vernier drive. Agroove machined along the axis of thestem of the valve increases in depth ata controlled rate per unit length. Effec-tive opening ranges from 0 to 0.000024in.2 and leak rate ranges to 1.8 stdcm'/sec for 25 turns of the valve. (Vac-tronic Lab Equipment, Inc., Dept. Sci646, East Northport, N.Y.)

* PULSE GENERATOR produces pulses of1/2 ,usec duration at repetition frequen-cies between 0.5 and 150 Mcy/sec.Pulses can be continuously varied overa 10-to-I range in steps up to 50 Msec.Amplitude is 300 volts peak to peakinto a 93-ohm load. The unit can beself-triggered or synchronized exter-nally up to 30 kcy/sec. Calibrated de-lay ranges to 11,000 txsec are provided.(Arenberg Ultrasonic Laboratory, Inc.,Dept. Sci647, 94 Green St., JamaicaPlain 30, Mass.)

* ANALOG-TO-DIGITAL CONVERTER willdirectly convert the amplitude of car-rier system voltages to digital codeswithout intermediate a-c-to-d-c conver-sion. The unit is reversible and as adigital-to-analog converter it convertsparallel digital codes to a-c carrier volt-ages. The amplifier, comparator, andconversion networks will accept fre-quencies to 100 kcy/sec yielding accu-racies said to be +0.02 percent ±½l/2count. Units are available for conver-sion of voltage to 8-to-13 bit binary orto binary-decimal codes of 2, 3, or 4digits resolution. (Epsco, Inc., Dept.Sci649, 275 Massachusetts Ave., Cam-bridge, Mass.)

* HIGH-SPEED CAMERA SYSTEM consistsof the camera, camera control unit,light control unit, and flash lamp. Inthe camera a rotating mirror spun byan air turbine sends the image to therim of a circular film box. The cameracontrol unit contains the elements nec-essary for operation of the Kerr-cell

de Fonbrune Micromanipulator - HasSmooth, Uniform Pneumatic Movement

Improved de FonbruneMicro-Forge WithBinocular Body

Specifically developedfor use in the fabrica-tion of simple andintricate micro-tools ofglass or metal undercontrolled conditions.Use of the de Fonbrunemicro-forge is recom-mended with any typemicromanipulator. Theforge is now built withbinocular stereoscopicmicroscope. With thismodification, the im-age is observed erect-not inverted- in threedimensions, an import-ant factor in rapid,accurate work.

Affords new simplicity and flexibilityfor micro-studies in biological or

chemical technicsThe de Fonbrune micromanipulator hasproved to be of great value in micro-studies in many fields. In biology theinstrument is used in cell dissection andisolation . . . micro-injection and operationon protozoa . . . pH studies on living cells. . . isolation and transfer of single bacteria,etc. It has proved equally serviceable instudy of fibers and yeast cells, in investigat-ing oils, rust deposits, colloidal, and othermaterials.

Manufactured under exclusive license othe French patents, the instrument con-sists of a manipulator and receiver. Usewith any microscope . . . arranged forright or left hand operation. The micro-tool is mounted on the receiver; impulsesfrom the manipulator are transmitted tothe tool through sensitive pneumatic mem-branes. Within a range of 3 mm, the micro-instrument may be moved in any plane orangle by a single control. Ratio of displace-ment of control lever and micro-tool maybe adjusted from 1:50 to 1:2500.

Write for prices and descriptive bulletin T114.

aloe scientficDIVISION OF BRUNSWICK CORPORATION

General Offices: 1831 Olive, St. Louis 3, MissouriFULLY STOCKED DIVISIONS COAST-TO-COAST

22 JULY 1960 243

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electro-optical shutter. The flash lampis a standard high luminosity electronicflash unit. Framing rate is 480 to 1.6million pictures per second, dependingon mirror speed and frame size. At themaximum rate, 960 one-quarter frame35-mm pictures are taken in one run.Exposure time is adjustable from 0.05Msec. to 1.0 usec, independent of fram-ing rate. Camera and light source aretriggered by an external electrical signal.Delay between trigger and start ofphotography is continuously variablefrom 0.00004 to 0.01 sec. (Benson-Lehner Corporation, Dept. Sci645,1860 Franklin St., Santa Monica, Calif.)

* BLACK BODY INFRARED SOURCE is aminiature unit designed for calibratingthe seeking head of infrared guidedmissiles and other infrared sensitiveelements in the 2000 to 600°C tempera-ture range. Temperature control is pro-vided by a separate unit which sensesthe temperature of the radiating coreby means of a platinum resistance ther-mometer. The radiating element is apure silver core with a conically shapedcavity. The surface of the cone iscoated with a refractory material toincrease its emissivity to near unity.(Perkin-Elmer Corp., Dept. Sci658Norwalk, Conn.)

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1,000 laboratory and scientific chemi-cals available from B&A, and meet thesame high quality standards. They areavailable in small packages and com-mercial quantities, thus providing youwith a single source for all your needs. . . for laboratory, product develop-ment, and process use.For full particulars, data sheets and

technical information, phone or writeyour nearest General Chemical office.MT.M. American Potash & Chemical Corporation.

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244

* MOUSE BREEDING BOXES, made otpolyethylene, can be sterilized by auto-clave. A smooth finish is said to preventcapillary action, and a built-in nestingfeature prevents sticking. Punched lipsfor drying on washer conveyer areavailable. (Consolidated Molded Prod-ucts Corp., Dept., Sci652, 329 CherrvSt. Scranton 2, Pa.)

* DIGITAL DISPLAY UNIT can also serveas a general-purpose oscilloscope. Theunit provides a 6- by 10-cm raster pres-entation of digital data shown as cath-ode-ray-beam modulation by means ofbistable intensity circuits. Positive-goingpulses of 2 volts or greater intensify thetrace while negative-going slopes of 2volts extinguish the trace. Horizontalsweeps are generated internally at 5 to50,000/sec. External sweeps may alsobe supplied with full-scale deflectionproduced by 300 mv. Step voltages hav-ing amplitudes from 600 mv to 30 voltswith rise times up to 0.07 jusec producea full-scale vertical raster. (WatermanProducts Co., Inc., Dept. Sci650, 2445Emerald St., Philadelphia 25, Pa.)

* pH METER is a direct-reading instru-ment incorporating both a 0-to- 14 pHscale and an expanded scale with 2.0pH full-scale graduated in 0.1 pH units.Any 2-pH span can be selected for full-scale expansion. pH measurements aresaid to be accurate to ±0.003 pH. Mil-livolt readings may be obtained overany 2)00-mv span from 0 to 1400 mvwith accuracy said to be +2 mv andrepeatability +0.3 mv. (Beckman Sci-entific and Process Instruments Divi-sion, Dept. Sci643, 2500 Fullerton Rd.,Fullerton, Calif.)

* TIMING SYSTEM includes a crystal-and oven-controlled frequency stand-ard; a frequency divider which furn-ishes 60 cy/sec; a stroboscope on whosescale WWV signals appear visually forcorrection to WWV time; a power am-plifier to boost the 60 cy/sec signalto 15 watts; a clock and photocell-gated programmer that provides 10-sec.1-min, 30-min, and 1-hr timing pulses:and a control unit that provides foraural monitoring of signals. Accuracy issaid to be within +0.1l sec/wk. Operat-ing power is provided by 24-volt bat-teries. (Geotechnical Corp., Dept.Sci651, P.O. Box 28277, Dallas 28,Tex.)

O NITROGEN ANALYZER performs auto-matically the micro-Dumas method ofanalysis. The operator is required onlyto prepare, weigh, and insert a sample-packed combustion tube, and adjust andread a counter indicating nitrogenvolume. Determinations at levels aslow as 0.01 percent are said to be possi-ble with results within ±0.15 percentof theoretical for routine materials.

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with Beckm a nomicroelectrodes**eliminates uncertainty of visual detection!

Now. .titrate even a sintgle drop-easily and accurately-with G15654 MANOSTAT MICROTITRATORthis modification of the Gilmont Ultramicroburet. Perform complete with Beckman M1icroelectrodes aiidmicrotitration electrometrically, without need for visual adjust- all accessories, but witlhout pH nmeter 245.00ment of end point. G15655 MICROTITRATOR ACCESSORYMan t M r is c e of bh o

KIT contains all equipmtient necessary toManostat Microtitrator is capable of both oxidation-reduction convert a Gilmont Ultramicroburet to N115654titration and acidimetry-alkalimetry ... with special electrodes 128.50for each process. May be used with any high-impedance pHmeter. Comes fully equipped with all accessories and solutions. Write For Alicrotitrator BulletinNothing else needed but your pH meter. *Pat. Appl. for **5Manufactured exclusively for Mlanostat Corp.

'/Ze FMIL GR Z,iVER a. 20-26 N. Moore Street * Dept. 427 * New York 13, N. Y.

nay naines, I)irector ot Researcn & lDe-velopment at Aurora Plastics Corp., findsthat he's also a test pilot for the firm'sready-to-fly model planes. These modelshave to perform as well as their prototypes,and Ray perfects the motors using hisUNIMAT to machine the small parts. Nomatter what the problem is, it can besolved with this multifunctional machine-shop-in-miniature. UNIMAT is ten inter-changeable machines on one base no largerthan a jeweler's lathe. WRITE FOR FULLYILLUSTRATED CATALOG AND PRICE LIST.

A ERICAN EDELSTAAL INC.350 BROADWAY, DEPT. AG N. Y. 13, N. Y.

Grip Anything 0-32 'Dia.with NEW LaPINE CLAMPSReach for this clamp and you're always right!It is precisely designed to do more clampingjobs for you than any other clamp available.Its die-cast aluminum alloy jaws hold any object-fine wires, thermometers, beakers, and even sepa-ratory funnels-round or irregularly shaped. It ismade like a fine drafting compass, yet extremelyrugged. Fine adjustment provides positive clamping.No.S763' CLMP Each.................$2.50No. 576-I CLAMPS Each, in lots of i2.. 2. 25

Write for discounts on larger quantitiesARTHUR S. LaPINE and COMPANY6001 South Knox Avenue * Chicago 29, Illinois

246

Flexible combustion cycles are said toaccommodate an almost unlimited vari-ety of organic nitrogen compounds, in-cluding heterocyclic nitrogen. Deter-minations are performed at the rate offour to five per hour. (Coleman Instru-ments Inc., Dept. Sci654, Maywood,Ill.)

* ROTARY TUBE ELECTRIC FURNACE iSdesigned for continuous-flow calciningor sintering of ceramic and metal pow-ders. The impervious mullite tube usedis adjustable in rotational rate from 0to 6 rev/min. Hot-zone length is 36 in.and diameter is 4½/8 in. Tilt is adjustablefrom 0 to 5 in. Operating temperaturesup to 2500°F are attainable. Heatersare silicon carbide. (Pereny EquipmentCo., Inc., Dept. Sci648, Columbus.Ohio)

* TRANSFER VOLT-AMMETER measuresa-c voltage and current between 5 cyand 50 kcy/ sec with accuracy said tobe within ±0.05 percent. Full-scalevoltage ranges from 0.5 to 300 voltsand full-scale current ranges from 7.5ma to 5.0 amp are covered in twomodels. Operating principle is the com-parison of heating effects of an un-known alternating current with an ad-justed direct current and measurementof the latter with a null potentiometer.Internal mercury cells provide the d-csource. (Engelhard Industries, Inc.,Dept. Sci659, 113 Astor St., Newark,N.J.)

* POWER ISOLATOR provides up to 300v-amp output at 115 volts a-c isolatedfrom line voltage and line ground. Ashielded transformer and a feedbackisolation circuit are used. Loading ofthe output to ground is less than 2 pfcapacitance and greater than 50,000megohms. The device is portable andmeasures 12 by 11 by 6 in. (MoellerInstrument Co., Inc., Dept. Sci660,Richmond Hill 18, N.Y.)

* TAPE SIMUI.ATOR provides manualentry of data into punched tape sys-tems. The device has a capacity of 80bits of information, each entered by aptushbutton on the instrument's panel.Arrangement of the buttons in ten linesof eight channels coincides with eight-channel punched-tape code. Pushbut-tons light up when depressed. The simu-lator substitutes for a tape reader forperforming check-out and verificationfunctions or may act as an auxiliarysignal source. (Hallamore ElectronicsCo., Dept. Sci655, 714 N. BrookhurstSt., Anaheim, Calif.)

* DATA TRANSFER SYSTEM ultilizes digi-tal techniques for long-distance point-to-point or party-line transfer of analogvoltage data over voice-quality trans-mission circuits. The standard system

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provides for transmission of up to threechannels of analog information withaccuracy said to be ±0.05 percent offull range and resolution of 0.006 per-cent of full scale at data sampling ratesof ten per second in each channel. Awide range of signal levels is accom-modated in addition to the standard±+10 volts. Parity checking and identi-fication of data source is permitted.(Vitro Laboratories, Dept. Sci657, 200Pleasant Valley Way, West Orange,N.J.)

* RATE TURNTABLE is a portable testunit for mounting rate gyros, antennas,guidance assemblies, and other com-ponents requiring imposition of con-stant rate of turn for performancechecking. The basic unit provides asingle rate about a vertical axis; modi-fied units provide multiple rates, tiltingto polar or horizontal axes, or servodrive. (Sterling Precision Corp., Dept.Sci656, 17 Matinecock Ave., PortWashington, N.Y.)

* PHASE AND RATIO METER providessimultaneous readings of phase angleand amplitude ratio between two radio-frequency signals. Frequency responseis 150 kcy to over 100 Mcy/sec, andthreshold sensitivity is 50 mv. The in-strument combines a frequency con-verter with the manufacturer's type 405phase meter. The converter, used withan external oscillator, converts two ra-dio-frequency signals into audio signalsof identical phase relationship and pro-portional amplitude. Outputs are pro-vided for input to recorders. (Ad-YuElectronics Lab, Dept. Sci666, 249-59Terhune Ave., Passaic, N.J.)

* COUNTER-TIMER, fully transistorized,provides measurement of frequencyfrom 0 to 10 Mcy/sec, time intervaland period from 0.3 ,usec to 108 seconds,frequency ratio to 107, and phase to 0.1deg. Readout is by means of in-line elec-trode tubes. Three d-c amplifiers have1-megohm input impedance and 0.1-volt r.m.s. sensitivity. Power consump-tion is 50 watts. (Systron Corp., Dept.Sci6661, 950 Galindo St., Concord,Calif.)

* FLUOROMETER is basically an opticalbridge that measures the difference be-tween light emitted by a sample andthat from a calibrated light path. Asingle multiplier phototube within amechanical light interruptor samplesthe two light beams and provides anoutput signal whose phase depends onwhich of the beams is the stronger. Thissignal is used to effect balancing of the

The T/A Juno and Cutie Pieare the most widely used

survey meters in the world.

HEALTH PHYSICS

0

0

0

0

T/A has continually led in thedevelopment of personnel monitorsfor the automatic detection andmeasurement of radiation contamination.

Beta-Gamma Hand & Foot Monitor (Illus. at left)Portal Monitor (Illus. at right)Alpha Hand MonitorsLaundry Monitors

two beams by means of a cam. About 5parts of quinine sulfate per billion pro-vides full-scale deflection on the mostsensitive range. Linearity is said to be 1percent and readability 0.5 percent or

22 JULY 1960

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better. The instrunment may be used asa nephelometer to resolve as little as0.01 parts of silica per million. (ArthurH. Thomas Co., Dept. Sci674, P.O. Box779, Philadelphia 5, Pa.)

* SWEEP-SIGNAL OSCILLATOR furnishesoutput frequencies from 800 to 1400Mcy/sec. Output power is 10 mw andoutput impedance 50 ohms. Outputpower is held flat within ±-1 db overthe entire range by a leveler circuit.Sweep operates as 30 cy/sec. Manualtuning over the entire range is alsoprovided. (CGS Laboratories, Inc.,Dept. Sci672, Wilton, Conn.)

* SPECTROPHOTOMETER for the ultra-violet and visible ranges is a fully auto-matic, double-beam grating instrument.The monochromator incorporates twodiffraction gratings, each with 1200grooves per millimeter. Absorptionspectra, reflectance spectra, and emis-sion spectra can be recorded. A singlelever positions a hydrogen. tungsten, ormercury lamp for rapid scanning of theultraviolet spectrum without a break inthe record. Speed of wavelength scan isautomatically adjusted to the complexityof the spectrum being scanned. (Bauschand Lomb Optical Co., Dept. Sci670,Rochester 2, N.Y.)

NALGENE serves You right!"Serves you right" the way it handles easily-no needlessweight, Ino slipping even when wet . . no breakageproblems. You can ask a great deal of NALGENE Lab wareand get it. Beakers, Carboys, Flasks, Funnels, Graduates,Bottles, Pipets, Centrifuge and Test Tubes-all surprisinglylowv in cost. NALGENE is the practical, efficient lab warethat keeps its word . . . aliways dependable!

NalTigene Lab carec is prouingitts dependability inr "OperationDeep F r (e(z(. AlI(AfiirdoSoundcl-An taret ica

* v,,3THENALGE CO. INC. ROCHESTER 2, NEW YORK

248

For ouir Catalog1--459-w rite Dept. 157

* ELECTRONIC FLASH for high-speedphotography delivers a single flashwhose duration is controllable to cor-respond with the writing rate of thecamera. Wave form is square with riseand decay times of the order or 40usec. Duration settings are 8.7, 11.15.14.75, and 22.25 msec. (Beckman andWhitley, Dept. Sci673, San Carlos,Calif.')

* POLAROGRAPHIC INSTRUMENT forprocess monitoring performs automaticrepetitive samiipling, analytical pretreat-ment, and polarographic analysis ofliquid from either of two sources, andrecords the results on a continuousstrip chart. Sample and reagent aremixed by a stream of electrolytic hy-drogen generated externally. Pretreat-ment unit and polarographic unit areeach housed in steel cabinets and elec-trically interconnected. The pretreat-ment unit incorporates automatic pi-pettes for samples and reagents, polaro-graphic cell, hydrogen inlet valve.mercury receiver, automatic sequencecontrol circuit, power supply, and con-trol panel. Over-all accuracy is said tobe + 5 percent or better. (Baird & Tat-lock, London, Ltd., Dept. Sci653,Chadwell Heath, Essex, England)

* DIAGNOSTIC AUDIOMETER uses a pho-tocell to interrupt tone signals. Interrup-tion is said to be free of accompanyingclicks or pings and free of give-awayhand motions, a slight movenLent ofthe finger being sufficient to start orstop the signal. Frequency range is 125to 8000 cy/sec. Weight with accessoriesis 13 lb. (Acousticon International, Dic-tograph Products Inc., Dept. Sci662,Jamnaica. N.Y.)

* OSCIL LOSCOPE DOLLIES provide a 2.0-deg viewing angle. Storage areas areprovided for preamplifers, and a drawerfor accessories. A rubber gasket pre-vents damage to instruments while in-stalling or removing. Casters are 5 in. indiameter, rubber tired and ball bearing.Three power outputs and one input areincluded. (PBR Manufacturing Co..Dept. Sci663, 861 E. Luzerne St., Phila-delphia 24, Pa.)

* VOLTAGE-TO-FREQUENCY CONVERTERdevelops a frequency proportional to in-put voltage with long-term accuracysaid to be within +0.1 percent. Fre-quency range is 0 to 100 kcy/sec. Full-scale range can be switched from 0.1volt through 1000 volts in five steps.Input polarity is automatically indi-cated. Models are available for rack.module, or cabinet mounting. (VidarCorp., Dept. Sci664. 2107 El CaminoReal, Palo Alto, Calif.)

JOSHUA STERNNationial Butreaut of Standards,Wasliington, D.C.

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New ProductsJoshua Stern

DOI: 10.1126/science.132.3421.240 (3421), 240-248.132Science 

ARTICLE TOOLS http://science.sciencemag.org/content/132/3421/240.citation

PERMISSIONS http://www.sciencemag.org/help/reprints-and-permissions

Terms of ServiceUse of this article is subject to the

trademark of AAAS. is a registeredScienceAdvancement of Science, 1200 New York Avenue NW, Washington, DC 20005. The title

(print ISSN 0036-8075; online ISSN 1095-9203) is published by the American Association for theScience

of Science. No claim to original U.S. Government Works.Copyright © 1960 The Authors, some rights reserved; exclusive licensee American Association for the Advancement

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