Kodak reports to laboratories on:a new optical element...a tip for x-ray diffractionists...spectrophotometric solvents for the infrared

AxiconsThe axicon has been invented. Tothe lens, the prism, and the mirror-the basic elements of optical de-sign-there has been added the axi-con. It could have been invented in15th-entury Florence, or in Res-toration England for presentationat an early session of the Royal So-ciety, but it wasn't. It was inventedin no garret, but in this bright andshining factory overlooking theGenesee River in Rochester, N. Y.,

by John H. McLeod, a Kodak op-tical engineer. This is incredible.Our times seem far too complex,our science and technology far tooadvanced for a man to invent any-thing as simple as the axicon in thesixth decade of the 20th century.But listen to Doctor McLeod:"A search for a universal focus

lens has led to a new class of opticalelements. Probably the most im-portant of them is a glass cone.This class has the common prop-erty that a point source on the axisof revolution is imaged to a rangeof points along the axis. Such ele-ments do not, therefore, have adefinite focal length. The word 'axi-con,' meaning axis image, has beencoined to cover this type of element.[Note: He had to coin a word. Therejust wasn't any existing word toserve the purpose.] Axicons formimages only of small, bright objects."One application is in a telescope.

The usual spherical objective is re-placed by a cone. This axicon tele-scope has no focusing movement

but is in focus for targets from afoot or so to infinity. It can simul-taneously view two or more targetsplaced along a line.

"If a light source is added to thetelescope with a suitable beamsplitter, it becomes an autocollima-tor. It can do more than an ordinaryautocollimator, however, for, in ad-dition to checking the perpendicu-larity of a mirror, it can simultane-ously view one or more targetsalong the line of sight. (He meansmore than "view." At a distance of100 feet, the position ofa target canbe determined to .001", and even anon-technical executive has done it.In angle, this means an accuracy of1/5 second.]"A useful form of axicon is a re-

flecting cone. It will return an imageof a point source back to the sourceover a range of distances dependingon the cone design. This form may

be used for the precision checkingof lathe beds and the like, or forchecking the flatness of surfaceplates."

Ifyou would like to use a line of lightin space as a tool, get in touch withEastman Kodak Company, SpecialProd-ucts Sales Division, Rochester 4, N. Y.

Advice on diffractionWe can perform a slight but perhapsuseful service for practitioners ofx-ray diffraction by showing how toget rid of one of the two images onopposite sides of Kodak IndustrialX-ray Film, Type K. This film,though made for industrial radiog-raphy, happens to be our fastest for

diffraction. Researchers with mod-est budgets who regard film as theleast expensive and most versatilex-ray receptor for diffraction pat-terns will appreciate the economicadvantages over the tricky andcostly business of launching a spe-cial, extra-silver-rich, single-coatedfilm.

Write Eastman Kodak Company,X-ray Division, Rochester 4, N. Y., fora reprint on removing the second imageand a copy of our x-ray diffraction filmselection chart.

Windows and compatibilityWe announce three additions to thelist of liquids specially selected fortransparency in certain spectral"windows" in which they are usefulas spectrophotometric solvents.Methylcyclohexane (Eastman S946)is principally of interest for theultraviolet. Nitromethane (EastmanSI 89) and Bromoform (Eastman S45,and we stabilize it with Diphenyl-amine) both have too high a cut-offfor ultraviolet spectrophotometry,but we think that for infrared workit's useful to have them available forsome happy combination of "win-dow" location, compatibility, andsolubility which theymay offer a fewlucky spectrophotometrists. This ishow they stack up for transparency:

These three are part of the line of 15Spectro Solvents, which are part of theline of some 3500 Eastman OrganicChemicals, which are part of the servicethat makes laboratory time today moreproductive. For a chart of the otherSpectro Solvents and for the solventsthemselves, write Distillation ProductsIndustries, Rochester 3, N. Y. (DivisionofEastman Kodak Company).

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

GET YOUR ADVANCE COPYof the General Program-Directoryof the Berkeley Meeting of the AAAS

By first class mail - early in DecemberThe General Program-Directory of the 121st Meeting of the AAAS on the campus of the University

of California, Berkeley, Dec. 26-31, 1954, will be available to anyone, at cost, within the first week inDecember-whether he can attend the Meeting or not. You will want the General Program-Directoryfor your reference shelf.

Program content

1. The three-part General Symposium: "Science andSociety."

2. Programs of the 18 AAAS sections (symposia andcontributed papers).

3. Programs of the more than 70 participating societies.4. The Special Sessions: AAAS, Academy Conference,

Third Berkeley Symposium on Mathematical Statis-tics and Probability, Conference on Scientific Edi-torial Problems, National Geographic Society, Pa-cific Science Board, Phi Beta Kappa, Phi Kappa Phi,RESA, Sigma Xi.

5. Details of the Gymnasium for Men-center of theMeeting-and campus.

6. Titles of the latest foreign and domestic scientificfilms to be shown in the AAAS Science Theatre.

7. Exhibitors in the 1954 Annual Exposition of Scienceand Industry and descriptions of their exhibits.

Directory content

1. AAAS officers, staff, committees for 1954.

2. Complete roll of AAAS presidents and their fields.

3. The 260 affiliated organizations.

4. Historical sketch and organization of the Associa-tion; the Constitution and Bylaws.

5. Publications of the Association.

6. AAAS Awards and Grants-including all pastwinners.

7. Membership figures by sections.

8. Section committees (Council members) in detail.

9. Local committees.

10. Future Meetings of the AAAS-through 1958.

Advance RegistrationAdvance registration has these decided advantages: 1)You avoid delay at the Registration Center upon arrival;

2)You receive the General Program-Directory in ample time to decide, unhurriedly, which events and sessions youparticularly wish to attend; 3) Your name is posted in the Visible Directory as the Meeting opens.

The following coupon may be used both by advance registrants and by those who wish onlythe advance copy of the General Program-Directory.

--- THIS IS YOUR COUPON FOR AN ADVANCE COPY OF THE GENERAL PROGRAM-DIRECTORY --

l a. 1 Enclosed is $2.50 for my advance Registration Fee which brings me the Program-Directory, ConventionBadge, and all privileges of the Meeting.

lb. FO Enclosed is $1.50 for only the Program-Directory. (It is understood that, if I should attend the Meetinglater, the Badge-which is necessary for all privileges of the Meeting-will be secured for $1.00 more.)

(Check one)

2. FULL NAME (Dr., Miss, etc.) ....................................................................(Please print or typewrite) (Last) (First) (Initial)

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Please mail this Coupon and your check or money order for $2.50 or $1.50 to theAMERICAN ASSOCIATION FOR THE ADVANCEMENT OF SCIENCE

1515 Massachusetts Avenue, N.W., Washington 5, D. C.

IOA SCIENCE, vor,. I 210

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A NIew HIGH-SPEEDMICRO-HEMATOCRIT CENTRIFUGEFOR CAPILLARY BLOOD TUBESRapidly increasing recognition of the time and labor

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