PROPERTIES:Molecular weight.......... 159.83Atomic weight ............. 79.916

Specific gravityat 20/15lC. ............. 3.120

Pounds a gallonat 20°C .......................26.0

Boiling point-5......58.8°C.

Freezing point ...............-7.2 C.

Freely soluble in alcohol,ether, carbon tetrachloride,chloroform, concentrated HC 1,aqueous solutions of inorganicbromides

SPECIFICATIONS:Bromine, not

less than..........- 99.7'/.

Specific gravityat 20/1 5C.,not less than- 3.1

Chlorine, not morethan -0 . 0.15%

Iodine- None

Non volatilb,less than- 0. .01 %

Water Content-- 0.003% Max.

A NEW BROMINE PLANT* at El Dorado, Arkansas,will provide a large, dependable source of high-quality bromine at lowerdelivered cost in volume. This added capacity to our present productionfrom plants at Saint Louis and Manistee, Michigan permits active researchby you on this basic chemical element to take advantage of bromine'sunusual and unique properties. and characteristics. Investigate the possi-bilities of bromine and bromides in your business.

*A joint-venture project of Michigan Chemical Corporation and Murphy Corporation of El Dorado, Arkansas.

WHAT BROMINE OFFERS YOU

HIGHER YIELDS

Bromine compounds give higher process-ing yields in: Quarternary salt forma-tions; Grignard reactions in the aromaticseries; nitrile formations; hydrolysis tocarbinols; Ullmann reactions, and Re-formatsky reactions.

PROCESSINGADVANTAOES

Bromine is handled as a liquid doesnot require pressurized equipment.

Oxidation potential of bromine is lowerthan that of elemental chlorine or fluor-ine. This minimizes decomposition of hy-drocarbons in halogenation reactions.

Melting points of bromides are higherthan those of chlorides or fluorides. Thisusually makes isolation easier- an im-portant advantage to the research chemist.

Bromine compounds have exceptionallyhigh densities -the highest of any or-ganic compounds with few exceptions.This suggests uses in processes involvingliquid- liquid separations.

Various inorganic bromides are useful-catalysts in reactions involving intra-molecular rearrangements.

NEW PRODUCTOPPORTUNITIES

Bromine imparts greater fire resistance toorganic compounds than low molecularweight halogens. This property hasproved useful in fire extinguisher fluidsand in fire proofing cloth and has appli-cation in plastics and coatings.

New pharmaceuticals are possible withbromine compounds as intermediates.

Bromine and compounds, which readilyrelease bromine, are active germicides,bactericides and algicides.

C-56.9 - _v J.S. Pot. Off.

Michigan Chemical will be glad to aid you with your present bromideneeds, or to help you in basic bromine research. Write or phone us.

MICHIGAN CHEMICAL CORPORATION

529 Bankson Stret, Saint Louis, Michigan

EASTERN SALES OFFICE: 230 Park Avenue, New York 17, New York

*T.M.

YOM Cs rely SCient Predvts Ainsworth babnces * Americen Optical microscopes B.B.L culture media Banstead stills * Bausch & Lomb microscopes

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" ~~~Radioisotopes make it possible to diagnose Depend on the Best-Depend on Berkeleyu ~~~many diseases in the laboratory. BerKeley BeklyrdostpXisrmnai-] I~~~-31' equipment provides a single source Breerdostpisrmnaina" ~~~~that handles many tests. be used to:" ~~~Designed primarily to measure thyroid i" ~~~uptake and urinary excretion in the diag- 1. Determine thyroid functiona3 nosis of -thyroid disorders, Berkeley's 1-31 2. Map thyroid gland activtity and deter-XE ~~~isalso readily adaptable to other radioiso- miesosecrsX ~~~~tope applications.

mieiooecre

t ~~~~Berkeley has concentrated its efforts in 3. Locate thyroid carcinoma metastases .

R

. ~~~~perfecting equipment for clinical labora- 4. Localize brain tumors* | ~~tory applications. S. Measure blood and plasma volume| ~~~so,urce for Berkeley equipment-and you 6. Measure red cell volume and

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can depend on the conscientious attBenton surviral time3of your SP representative tO solve yource ele isotinstrmenato

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ofelty r-31 domprder-$1,370. cardiac output| ~~~~Accessories for specialized work with S. Radioassay diagnostic or

I-31 also available. therapeutic doses

EBerkeley hAs nt"sooto LeoFfg"-a Ltaodaex of c afrcnt m ao Js,pmoeadt res,., eqipment, A.E.C re., 4k.

Malliekrdt chemicals fLip r Berketleequipment yoUnd6rg hotplat. & fvrn * Kimble glssware * intrnational vontrifugme Hyand elinic0l"uipnt * Harbso R"gents

SCIENCE is published weekly by the AAAS, 1515 Massachusetts Ave., NW, Washington 5, D.C. Entered at the Lancaster, Pa., Post Office as second casmatter under the act of 3 March 1879. Annual subscriptions: $7.50; foreign postage, $1; Canadian postage, 50¢.

10 AUGUST 1956 247

I

...with EmphasisI

Internallonalcentrifuge model CM. . . for routine centrifugingDesigned for the moderate budget, the Model CMis a heavy-duty Centrifuge for all ordinaryapplications where very high speeds are not essential.It is an unusually versatile unit with interchangeableanalytical heads for spinning tubes and bottles inthe angle and horizontal positions and basket styleheads for filtration and clarification.

EMPHASIS ON FUNCTIONAL EFFICIENCYAll operating units are completely enclosed in ahandsomely modern functional cabinet of two piececonstruction, which incorporates shelves for extraheads and features International's new "Stor-a-Door"for storing shields and trunnion rings. Controls areeasily accessible and indicators are on eye-levelangle for utmost efficiency.

on Functional Efficiency

NEW IMPORTANT FEATURES

Stainless Steel Guard Bowl, corrosion resistant,easy to clean, no paint to chip or peel.Finger Touch Brake, for safe, smooth deceleration.

Autotransformer, stepless speed controlwithout heating.Electric Tachometer, non-mechanical continuousspeed indication.

Permanent Speed and Force Table, for quick reference.

Two-Piece Construction, for use as bench-ModelCentrifuge when desired.

SPECIFICATIONS

Speed - 1200 to 4500 r.p.m. - 290 to 3200 G.Capacity - 15, 50, 100 ml. tubes; 250 ml. bottles;3 liter baskets.Height - 39", Width - 20", Depth - 23".

International @ Equipment Co.1284 SOLDIERS FIELD ROAD * BOSTON 35, MASSACHUSETTS

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ters, sample holders, adapters and other accessories* Interference filters for high specificity of results and for

determining spectral distribution of the fluorescent light (Yi A-ii.|* High-sensitivity anephelometry for low degrees of turbidities /! rb* Fluorescence evaluation of powders, pastes, slurries, and | i(I1h1 |

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Write for Bulletin #392 to Write forBlletn 3 oLook for these familiar trade names-your assurance of quolitylAdams Centrifuges . Yankee Rotators . Gold Seal Slides andCover Glasses * Adams Laboratory Counters . Counting Chambers

PHOTOVOLT CORP.~~~~~~Yankee Shakers *Medichromes95 Madison Ave. New York 16, N. Y.

FARRAND®_] ~MONOCHROMATORS|

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Farrand Grating Monochromators are small, cor- chromators are reflection type replica gratingspact and convenient to use with microscopes, col- 400 lines per inch) made from master gratings oforimeters, photometers, and similar instruments and highest efficiency and resolution. The masters are

can be set up with auxiliary equipment for making produced in our own plant on the Farrand-Strongtransmission, absorption, emission, radiation, re- Ruling Engine which we manufacture in accord-flection, fluorescence and phosphorescence measure- ance with the design of Dr. John Strong of Johnsments or used for irradiation purposes. Hopkins University.The dispersing elements in the Farrand Mono- Bulletin No. 81IR upon request.

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SCIENCE, VOL. 124250

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Mod. 540~~~~~~~~ii

Kodak reports to laboratories on:

non-hygroscopic acetylcholine iodide ... a better chance of getting through tothe besieged brain ... recruiting talent for high-energy physics

A delightful businessYou sit one fine morning readingyour mail and lo, there is a letterfrom a researcher at a medicalschool in the green hills of Vermontwho wants to know why you don'tput up acetylcholine as the quater-nary iodide. Somehow, possibly byreading it in a book, he seems tohave learned that acetylcholine io-dide is not hygroscopic at all,whereas that well lnown vasodila-tor acetylcholine itself and its wellknown bromide (Eastman 2117) ab-sorb so much water from the airthat to try to weigh them out ac-curately is a nuisance. There doesn'tseem io be a solitary reason in theworld why you can't put up acetyl-choline iodide. You even think of away to make it from starting mate-rial less costly than acetylcholine.You try it and it works and the io-dide is non-hygroscopic. That par-ticular researcher is pleased at whatan agreeable fellow you are, andyou are pleased at the prospect ofall the acetylcholine iodide that allthe other researchers are going tobuy from you.So now all you have to do is to adver-

tise that Acetylcholine Iodide (Eastman7209) costs $2.60for 10 g. and is one ofsome 3500 highly purified organic chemi-cals sold by Distillation Products Indus-tries, Eastman Organic Chemicals De-partment, Rochester 3, N. Y. (Divisionof Eastman Kodak Company).

Movies with commentAs between 55 pages of typescriptto detail the progress on a certainproject for last month and sixminutes of Kodachrome movies todo the same, which has the betterchance of getting through to thebesieged brain?

Since you can't say everythingwithout words and since you haveto be quite rich to afford a full-dress

sound movie that is looked at onceor twice and filed for the record,you use a magnetically recordedcommentary. At the time we processthe film for your dealer (and youcan, if you wish, specify us as yourfavorite color film processor), wecan lay down a Kodak SonotrackCoating along the edge. While theKodascope Magnetic-Optical SoundProjector shows the picture, appro-priate extending remarks are spokeninto the microphone. Any remarksthat seem less than appropriatewhen the projector plays them backwith the picture have merely to berespoken. Automatically the boo-boo is wiped clean and replaced bywiser words.

This projector we have justbrought out now. We hadn'tthought it wise to take anybody'smoney for such a machine untilenough organizations had used ourdesign without trouble and hadliked the way it sounds.From Eastman Kodak Company,

Cine-Kodak Equipment Sales, Roch-ester 4, N. Y., one may expect an honestattempt at collaboration on sensible pro-cedures for using inexpensive soundmovies in technical communication anddocumentation.

Little black tracksRochester, a city which gets a fairamount of its living from the pho-tographic emulsion, has been thesite for the past six years of greatinternational conferences on nu-clear particle physics. It is mere co-incidence that photographic emul-sions are the source of much of theraw data that the savants come totrade, ponder, and debate. Yet, be-cause we make some of the photo-graphic emulsion they use, we areperhaps more awed than our butch-ering, baking, and candlestick-making fellow-townsmen at the

mighty intellectuality focussed onthe microscopic tracks of blackspecks that mark the births, en-counters, and deaths of nucleons,

leptons, mesons (light and heavy),and hyperons. Heremen and womenstrain every known resource ofthought and mathematics to build alogical structure strong enough tohold these "elementary" particlesuntil next year's conference, whenparts of it will surely come crashingdown as new evidence is presented.Not the least remarkable aspect

of this is the virtual certainty thathere and there in the land theremust be a kid (now in Cub Scoutsor possibly trying to understandrock 'n' roll) who, a few years fromnow, will be reading the proceed-ings of these conferences with asmile of tolerance for the pitifulerrors of the physicists who pre-ceded him. A parent or teacher whosuspects he knows such a kid has achilling responsibility.

Scientific American recently carriedan article, "The Tracks ofNuclear Par-ticles," pitched at those who have noknowledge of the subject or its vocabu-lary but who are blessed with vigorous,inquiring minds. We have bought 2,000reprints to give away. Requests shouldbe addressed to Eastman Kodak Com-pany, Professional Goods Division,Rochester 4, N. Y.

Price quoted is subject tochange without notice.

iiThis is one of a series of reports on the many productsand services with which the Eastman Kodak Company andits divisions are.. . serving laboratories everywhere

10 AUGUST 1956 285