New ProduictsFluorescence spectrophotometer (mod-

el SF-1) incorporates the optical andphotometric equipment in a singlebench top unit and provides doublemonochromators in both the excitationand fluorescence paths. The use of dou-ble monochromnators greatly reduces thestray light without significant reductionin efficiency. Second-order light presentwith excitation wavelengths above 400,u can be eliminated with the use of aninterference filter. Monochromatic lightfrom an a-c 100 watt xenon arc ex-cites liquid samples in square cuvettesat 90 degrees to the optic axis of theemission monochroniator, or flat sam-ples such as paper can be used. Thefluorescence double monochroniatorwith its higher rejection of scatteredlight is claimed to improve perform-ance with paper or turbid solutions byreducing the size of the scatter peak totolerable proportions. Full-scale deflec-tion is obtained with 0.5 part per bil-lion of quinine sulfate, and microsaniple attachments are available toreduce the usual 1-nil sample volumeto 4 ,l. The instrument is contained ina case 21 bv 22.5 by 15 inches high,except for the arc ballast and record-ing equipment. A cathode-ray oscillo-scope or x-y recorder can be used todisplay or record excitation or emissionspectra.-R.T..B. (Baird-Atomic, Inc.,Dept. S-342. 33 University Rd., Cam-bridge 38. Mass.)

Plankton sampler is light weight(about 85 pounds) and mav he towed ata speed of 1 2 knots to determine theplankton population in a given body ofwater. Its 8-foot titanium and stainless-steel bodv allows the sampler niorepotential usefulness (and faster serv-icing) than the Monel construction ofthe original niodel. A descendant ofthe Gulf III, the sampler's interior con-tains Monel or stainless-steel netting, avinyl cup to collect plankton and a cali-brated flowmeter to nieasure the amount

The material in this sectionl is prepared bythe following contributing writers:

Robert L. Bowman (R.L.B.). Laboratory ofTechnical Development, National Heart Insti-tute, Bethesda 14, Md. (medical electronics andbiomedical laboratory equiipment).

Joshtia Stern (J.s.), Basic Instrumnentation Sec-tion, National Btireau of Standards, Washing-ton 25, D.C_ (plhysics, computing, electronics,and nulclear equlipment).The information reported is obtained from

manufacturers and other souLrces considered re-liable. Neither Sc ienice nor any of the writersassumes responsibility for the accuraicy of theiniformation.

Address inquiries to the mantufacturer, men-tioning Scientce and the department number.

5 OCTOBER 1962

New Sylvania Electronic Viewfinder cam-era - with built-in monitor - permits per-fect pictLire composition. Lets youL controlprecisely the qLiality of the picture yourstudents will see on remote classroommonitors.Never before has a Viewfinder camera forprivate TV systems been available at aprice schools can really afford. It's thenewest addition to Sylvania Direct WireTV... one of the lowest-cost, easiest-to-useprivate TV systems.Sylvania Direct Wire TV helps overcomethe teacher and classroom shortage.Makes it easy to teach large groups. Effec-tive in showing lab experiments, micro-scope slides, and complex demonstrations.

Write for free Educational TV ManualThis manual has been carefully planned andwritten for school administrators and other

interested personnel. It isa thorough, up-to-date

- study of the value oftelevision in educationtoday. Discusses howTVcan solve vital problemsof today's overcrowded

SYLVANIAGENERAL TELEPHONE &ELEtTRON/6'S

schools. Answers many common questionsabout TV in education. Tells whatTV can bringto the classroom. Explains how schools canplan for TV. Describes equipment, and givesbasic information on how TV is transmittedand received -all in nontechnical language.This 32-page manual is the result of exten-sive research, and is the most complete andconcise study everoffered. It shouldserve as a valuableguide and introduc-tion to one of themost significanttechnological devel-opments in educa-tion since the in-vention of print-ing. Write today!

Sylvania Home & Commercial Electronics Corp.Marketing Subsidiary of

I Sylvania Electric Products Inc.730 Third Ave., Dept. S New York 17, N. Y.i Please send more information on

Sylvania's new low-cost Electronic II Viewfinder camera.I m Please send Sylvania's new Educational

i TV Manual and more information onhow to arrange a free visual commu-

I nication survey for my school. |

Name

School

| Address uI City Zone.State i

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COLE MAN

Refinery control labdetermines nitrogenautomatically onround-the-clock basisUsing the automated Coleman Nitro-gen Analyzer as basic equipment, thequality control laboratory of TheAtlantic Refining Company (Phila-delphia) determines nitrogen contentofpetroleum products down to 0.02 %nitrogen.Operated by control chemists on allthree shifts, the instrument providesa complete nitrogen analysis in as

little as 8 minutes. It is used forcritical quality control work with gas

oils, lube oil additives, greases andsynthetic detergents.The instrument is fully as efficient inthe control laboratory environmentas it has proven under carefully-con-trolled research laboratoryconditions.

Write for the specific method devel-oped by Atlantic Refining's ProductQuality Department for nitrogen de-termination in refinery fluids-Cole-man Technical Report S T-187.

COLEMAN INSTRUMENTS, INC.MAYWOOD, ILLINOIS

60

of water which flows through the net-ting. Remote opening and closing equip-ment, as well as temperature and pres-sure telemetering devices, are alsoavailable with the sampler. Some of theinherent disadvantages of a towedplankton sampler are overcome witha plainkton pump. It is immersible andbrings plankton-bearing water to recov-ery and filtering equipment aboard ship.The pump is a finned, titanium cylindercontaining an all-plastic surfaced pump(thus no metallic contamination of thewater) and a water-cooled, hermeticallysealed electric motor. Support, power,and telemetering wires are inside a thinvinyl output tube. Three hundred gal-lons per minute and speeds up to 10knots are possible.-R.L.B. (Oceanic In-struments, Inc., Dept. S376, Houghton,Wash.)

License-exempt strontium-90 solutionstandard (RS-90A) has a nominal ac-tivity of 3000 disintegrations per sec-ond in a total volume of three milli-liters. The strontium-90 and its yttrium-90 daughter activity is supplied in al.ON HC1 solution having a carrier con-centration of 0.027 g/lit. SrCl2- 6H20and 0.022 g/lit. YCI H20. The solutionis contained in a flame-sealed glass am-poule. The new strontium-90 standardenlarges the selection of NBS-certifiedstandards produced by Nuclear-ChicagoCorp. to a total of 18, 12 of which donot require specific AEC license. TheNuclear-Chicago model RS-90A solu-tion standard will be of particular in-terest to investigators without an AECby-product material license and to thosewho wish to standardize low-activitycounting samples in connection withstrontium-90 fallout studies. Price $32.-R.L.B. (Nuclear-Chicago Corp., Dept.S340, 359 E. Howard Ave., DesPlaines, Ill.)

The model 240 phase-sensitive volt-meter will operate as either a standardvacuum-tube voltmeter or as a phase-sensitive voltmeter. As a standard volt-meter, the instrument will measureeither the total signal or the fundamen-tal component of the signal. When oper-ated as a phase-sensitive voltmeter, thein-phase and quadrature componentsas well as the phase angle may be meas-ured at a single frequency. Internalfilters are used to reject noise andharmonics. Full-scale sensitivity maybe adjusted between 300,v and 300 v.The signal is displayed directly in voltson a mirrored-scale panel meter. Theinternal calibrated phase shifter covers

the full range from 0 to 360 deg with-out ambiguity. Input impedence to theinstrument is 10 megohms.-J.s. (Dy-tronics Co., Inc., Dept. S404, 5485 N.High St., Columbus 14, Ohio)

The model TE-60 incremental induc-tance bridge is designed to test induc-tors in which large d-c and low a-c rip-ple voltages flow simultaneously. Theinstrument incorporates a Maxwell-bridge circuit and includes componentsfor generating both a-c and d-c currentflow through the inductor being tested.Bridge balance is indicated by panelcontrol consisting of three-decade ca-pacitors, a resistance multiplier, and aQ-balance nulling variable resistor. In-ductance range is 0.1 to 1000 mh at60 volts a-c maximum and 40 amp d-cmaximum, and 100 mh to 10 h at 60volts a-c maximum and 1 amp d-cmaximum.-J.s. (Librascope Division,General Precision Inc., Dept. S348,670 Arques Ave., Sunnyvale, Calif.)

The model 75 portable potentiometervoltmeter consists of a 7.5-inch indi-cating meter, null galvanometer, resis-tors, switches, potentiometer, and bat-tery contained in a case 51/2 by 133/4by 123/4 inches. Voltage is potentio-metrically adjusted to obtain null in-dication on the galvanometer when theself-contained potential is opposed bythe unknown external potential. Batterypower supplied may be varied continu-ously to obtain full-scale output rangesof 500, 200, 100, 50, 20, 10, 5, and 2mv; and 20, 10, 5, 2, and 1 v. At nullindication on the galvanometer, thewide-scale meter indicates true open-circuit potential of the applied voltage.Galvanometer sensitivity permits reso-lution of 0.1 Muamp. Switching permitsdirect measurement of an external po-tential. Input resistance is 5000 ohmswhen the instrument is used as a direct-reading voltmeter. Accuracy is said tobe better than ± 1/3 percent of fullscale.-J.s. (Weston Instruments Divi-sion, Daystrom, Inc., Dept. S399, 614Frelinghuysen Ave., Newark 14, N.J.)

A 2-7r chromatogram scanner (Strip-Scanner I) can be used for thin-layerchromatography, thick gels, and bothlong and short paper strips. It scanspaper strips up to 50 feet long, using ashielded, thin-window, gas-flow detectorwith a choice of a Mylar window orultra thin membrane less than 100,ug/cm'. If an optional adapter is added,the instrument accepts gelling agentsused as an electrophoresis medium for

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hemoglobin studies or glass plates usedin thin-layer chromatography. Theadapter is recessed to prevent movementof the gels during scanning. The systemalso includes a single-channel chartrecorder with ten chart speeds. Standardend-window Geiger-Mueller tubes orscintillation counters may be substitutedfor the gas flow detector. Bulletin P-302.--R.L.B. (Atomic Accessories, Inc.,Dept. S333, 811 W. Merrick Rd., Val-ley Stream, N.Y.)

Solid-state digital clock (model 1200)presents time information on a front-panel, in-line, six-digit projection dis-play. In the standard version, a maxi-mum of 23 hours, 59 minutes, 59seconds is displayed. Time base is de-rived from the 60-cy/sec line frequencyor from an external one pulse-per-sec-ond input. Other models are availablewith other time ranges. Other optionsprovide: a 100-kcy/sec internal crystalcontrolled oscillator with 0.001 percentstability and associated countdown log-ic; buffer amplifiers that permit time-of-day information to be fed to associatedequipment for printout or automaticprocessing; temperature-controlled 100-kcy/sec oscillator with 0.00003 percentstability; preset circuit permitting syn-chronization of the 1 00-kcy/ sec timebase with an external standard; parallelstep-function outputs in addition to thestandard one pulse-per-second for fivedigits of the clock's range.-J.s. (WyleLaboratories, Dept. S405, El Segundo,Calif.)

The model PDA 675F two-channelprobability distribution analyzer willdetermine the amplitude probability ofone or two independent variables, theprobability density of a single variable,or the joint probability of two variables.Sampling rate is adjustable to 25,000per second. Used -with an appropriatedigital counter, the instrument meas-ures input voltage levels, compares thesewith a preset reference voltage, andreads out the number of all samples inwhich the amplitude of input is lessthan the reference voltage. For proba-bility densities, readout occurs when theinput falls between two comparisonlevels. In joint probability operation,either coincidence or anticoincidencecan be counted. Reference voltage rangeis selectable in 1-volt steps up to 10volts, and its level is then set by vernierwith accuracy ±0.1 percent of therange. Associated with the instrumentis a gate generator that serves to selectthe time interval over which the proba-5 OCTOBER 1962

loom it to optimum magnification!See it by any of six kinds of light!

First, Bausch & Lomb DynaZoom® Laboratory Microscopesmade history by offering continuous magnification from 17.5Xto 1940X. And now you can equip your DynaZoom Microscopefor the widest range of micro-investigation by any of six kindsof illumination:

BRIGHT FIELD-Hi-Intensity Base Illuminator, Opti-lume In-tegral Illuminator, or mirror-for universal application.ULTRA-VIOLET-condenser, objective, new high intensity mono-chromator-indispensable for cancer research.DARK FIELD-paraboloid and cardioid condensers-for hard-to-see subjects such as living spirochetes.PHASE CONTRAST-turret-type and long-working-distance ac-cessories-newly significant in blood platelet counting.POLARIZED LIGHT-polarizer and analyzer-for routine bire-fringence work.

FLUORESCENCE-exciter and barrier filters; non-fluorescingoptics; Hi-Intensity Base Illuminator-basic aid to acridineorange cancer detection.

Only DynaZoom Microscopes give you the exactly right mag-nification and the exactly right light. See.for yourself, in yourown laboratory, how DynaZoom takes the blind spots out ofmicroscopy . . . to show you detail you've never seen before.

BAUSCH & LOMB[ Please demonstrate DynaZoom Microscopes in my lab.

Please send me DynaZoom Catalog D-185.

BAUSCH & LOMB And I would like information on the following DynaZoom IIINCORPORATED accessories: E Bright Field aJ Dark Field a Fluorescence ll IDCORPORATED E Polarized Light Ea Ultra-Violet Dl Phase Contrast

I 75934 Bausch StreetRochester 2, N. Y. Professiona.

Address ............................

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A New Conceptin Ion Exchangers

SE-SephadexeIntroduction of ionic groups intoSEPHADEX, a hydrophilic insolubleproduct derived from cross-linking thepolysaccharide, dextran, makes possi-ble an entirely new series of ionexchangers. The SEPHADEX ion ex-changers have

High capacity* Low nonspecific adsorption

SEPHADEX ion exchangers make possi'ble the purification, separation andfractionation of a wide range of lowmolecular weight, complex organiccompounds, proteins, and related ni-trogenous substances with high yields.A diversity of types, both anionic andcationic, are available to meet specificrequirements. Have you investigated-

SE-SephadexActive group sulfoethyl

character cationic, strongly acidiccapacity 2.0-2.5 meq/g

SE-SEPHADEX is prepared in two forms:

C-25, which is highly effective for sepa-rating low molecular weight, complex-organic substances, and C-50, whichhas a far greater binding capacity thanC-25 for large size molecules-particu-larly useful for purification of proteins,enzymes, and related nitrogenouscompounds.SE-SEPHADEx has total exchange capac-ity of 2-2.5 meq/g. This product isavailable in the following sieve frac-tions: Coarse, Medium, and Fine.

-- PHARMACIA FINE CHEMICALS, INC.501 FIFTH AVENUENEW YORK 17, NEW YORKU Send me information onS SEPHADEX Ion Exchangers.

Name

Company

bility samples are taken. Triggered froman external pulse through a flip-flopcircuit, the gate generator will delaysampling and then control samplingtime for any desired periods so thatdata may be taken for any preselectedportion of a test or trial run.-J.s.

(GPS Instruments Co., Inc., Dept. S408,180 Needham St., Newton 64, Mass.)

Recorder uses a D'Arsonval move-

ment and records on pressure-sensitivepaper. Deflection of the meter move-

ment is unhindered during the non-

recording portion of the instrument'scycle. The record is obtained by a liftplate pressing a stylus, mounted on themeter movement's pointer, against theunderside of the pressure-sensitive pa-

per. After the stylus is released, themovement is free to assume a new posi-tion. A wide range of tape speeds up to15 in./hr is available. The chart is 21/2inches wide. Accuracy is said to be ±2percent of full scale for d-c and 3percent for a-c. Size of the recorder is5-21/32 by 3-1/32 by 1-11/16 inches.-i.s. (Amprobe Instrument Corp.,Dept. S400, 630 Merrick Rd., Lyn-brook, N.Y.)

Miniature core memory unit is avail-able as a sequential-access buffer, resetbuffer or sequential interlace memory.A selection of storage capacities of from72 to 4096 characters is available withcharacter loading and unloading ratesup to 100 kcy/sec. Size varies upwardfrom 30 in.3 depending on the unit'sstorage capacity. It will operate at am-

bient temperatures from -55° to+100°C and at 100 percent relativehumidity. Information is retained inthe memory when the power is shut off,and there is little or no power drainwhen in standby condition. The small-est unit weighs 25 ounces.-J.s. (Di/AN Controls Inc., Dept. S403, 944Dorchester Ave., Boston 25, Mass.)

The LS-19 inertial vertical-referencesystem is said to be capable of sensingthe vertical within ±+1.5 minutes of arc,

r.m.s., with maximum excursions lim-ited to 3 minutes. It consists of an

inertially stabilized Schuler-tuned plat-form, an electro-mechanical analog de-vice that acts as a pendulum equal inlength to the radius of the earth. Theresulting simulated pendulum has a

period of 84 minutes and maintains itsproximity to the vertical even underviolent aircraft maneuvers.-J.s. (Aero-flex Laboratories, Inc., Dept. S389,48-25 36th St., Long Island City, N.Y.)

EXHIBITNew York ColiseumCONFERENCEHotel New Yorker

More than 400 exhibits,and over 200 papers, willdemonstrate and reporton . . .

PROGRESS ININSTRUMENTATION /62

Plan now to attend!

INSTRUMENT SOCIETYof AMERICAPenn-Sheraton Hotel, 530 Wm. Penn PlacePittsburgh 19, Pa.

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