letters A Historical Injustice Rectified To the Editor:
The readers ofthe Journal of Chemical Education will be pleased, as I was, to learn of a case where history that was unjustly recorded h a s been changed. I n Ruth Lewin Sime's excellent article [1989,66, 3731, "Lise Meitner and the Discovery of Fission," the statement is made: times she IMeitner] is rendered complekly mvlsiblr,as in the Deutsches Muarum in Munich, far example, where the apparatus she desi~med. is now displayed under a rlkm whluh reads: "Wurktablc of Otto Hahn." A plaque nearby mentluns Fritz Str.lssman; Llrt Meitner does not appear ar all.
I S 0 recommendations (2)are effectively identical. I t seems to me t h a t this recommendation covers all bases, and that the extended argument (3, 4, and references therein) about the proper units for (stelradian could have been avoided if SI or IUPAC recommendations had been consulted and cited. Of course, there may be reason to question the SI recommendation, but that recommendation should the reference point for beginning the argument. .... ....
At
The reference cited by Sime for this statement is a 1981 work by F. Krafft. During a June 1990 trip to Munich I spent some time in the superb Deutsches Museum and was pleased to find that the above quoted statement is no longer true. Above the display of the fission equipment, equipment assembled from that originally used in three different rooms of the Kaiser Wilhelm Institute i n Berlin, is a large plaque reading: Versuchsallfbau,mit dem die Wissenschaftler Otto Hahn, Lise Meitmr und Fritz Strassman 1939 die Kernspaltung entdecken. Under this inscription, in smaller letters, is the English: The Experimental Apparatus with which the Team of Otto Hahn,Lise Meitner and Fritz Strassman Discovered Nuclear Fission in 1938.
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I do not know when this correction was made. The English version of the Deutsches Museum: Guide through the Collections, dated July 1987, still does not mention Lise Meitner in connection with this display.
Justine Simon Walhout Rockford College Rockford, IL 61 108
Literature Cited 1. RTPAC, Quonaties, Unila and S p b d a in Physical Chemistry;
2. Infernational Organnization for Standardization (ISOI, IS0 3111 Quantities and Unifs o/Spocerind Erne: Geneva, 1978.
3. Canageratna, S. 0 . J Chom Educ. 1991, 68,709. 4. WadlingebR. L. J. Chem. Edue 1991.68, 709-110.
Robert D. Freeman Oklahoma State University Stillwater, OK 74078
An Error in Reporting Errors To the Editor:
I would like to report an error in the article, "An Evaluation of Drop Counting a s a Volume Measurement" by James Ealv and Miles Pickerine 11991.68. A1201. The authors repo;t that the standard dekation i n a set i f individual weieht measurements was M.00003 e. Thev further report tlhat the weights of the drops they were evaluating were obtained bv difference and thus the absolute error of their weight meisurements was "twice that of the individual measurement, that is f0.00006 g". This is incorrect. The propagation of random error in addition or subtraction is calculated by summing the squares of the errors of the individual measurements and taking the square root of that sum ( I ). Using this formula the absolute error of their difference measurements should be f0.00004 g. Literature Cited 1. Harris, D.C.&onfifafiueAnolyais, 1991;p42.
Units for (Ste)Radian
~h~ units radian and steradim are described as y,~ supple. mentary units'. However, in chemistry, as well as in they are usually treated as dimensionless derived units, and this was recognized by CIPM in 1980. Since they are then of dimension 1,this leaves open the possibility of including them or omitting them in expressions of SI derived units. In practice this means that rad and sr may be used when appropriate and may be omitted if clarity is not lost thereby.
432
Journal of Chemical Education
3rded.;W H. Reeman sndCompany:NewYorL, Colleen M. Byron Macalester College St. Paul, MN 55105
To the Editor.
As most of u s recognize, CIPM/BIPM-International Committee/Bureau on Weights and Measures, by formal treaty, establishes global standards for units; the (current, standards are aenerallv referred to a s SI. SI includes s m cific recommenldations for radian a n d steradian. The IUPAC version (11,which is based directly on the CIPM documents, is:
Mgls, I.: et 4.. Eds.:
Blackwell: Oxford, 1988;p 66.
Lots of Liauid Lavers TO the Edlror:
The article in your August 1991issue, p 655, "Liquid Systems with M~~~ ~h~~ T~~ ~ ~ ~ iphasesz2 ~ ~ byi jan b l Kochansky, reminded me of the frontispiece in Hildebrand a n d Scott' s classic Regular Solutions (Prentice-Hall, 19621, in which there is a picture of ten stable liquid layers. David C. Locke Queens CollegeXUNY 65-30Kissena Boulevard Flushing, NY 11367
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