From the Editor Last November there was an electronics show in town, and we

journeyed in to hear the papers and see the exhibits. We felt almost a t home: the I E E E people have apparently decided that radar, radio, and television are all old hat, and the newest thing is optics and spectroscopy (which they have renamed quantum electronics). Surely a source in which one puts electricity in and gets light out is really electronics, and a detector, in which one puts light in and gets electricity out, is also electronics. And a laser, in which one puts in one kind of light in order to get out another kind of light, is rather obviously just a combination of the two electronic processes just mentioned. Our own haphazard exposure to electronics, of which we only vaguely recall class B amplifiers and Thevenin's theorem, did not strike us as particu­larly optical, but tha t was long ago, before there was any money in optics.

Of course we really cannot complain, for even in this journal we accept papers describing the operation and performance of radiation detectors, or the construction of preamplifiers for such detectors, in which the optics involved is rather modest. Our reasoning with such papers is that the journal is fundamentally striving to serve an audience rather than a topic, and the audience working in optics has many related interests besides lens design. We suppose the electronic engineers follow the same reasoning. I t is somewhat like the practical definition of physics: physics is what physicists do.

Among the exhibits were many that would interest optics people, several laser exhibits in particular, but we happened ac-cidently to stop first a t an exhibit (from Ft . Knox, Kentucky, as we recall, a rather unlikely spot) that was a description of various stages of eye damage from lasers, so we averted our eyes from all of the laser exhibits, and instead inspected such relatively safe exhibits as Amphenol plugs.

Perhaps we have been an editor too long, but we now find we cannot listen to a talk, look at the speaker's lantern slides, or browse the exhibits without wanting to change units or correct nomenclature. One of the slides of the lead paper on lasers plotted the rate of drift of his laser in "cycles/sec/sec" when he surely meant "(cycles/sec)/sec". In the exhibits we found our-self gazing at the dials of the instruments to see what units they were calibrated in. Among strip chart recorders, for example, we observed that Leeds and Northrup recorders feed paper in in./ min, and the Brush recorders in mm/sec. Torque meters, we noticed, were all calibrated in in.-oz and the salesman did not think it would be possible to express torque in any other units. The tension meters measure low tension in grams up to 1000 g, then high tension in lb to 50 lb. One meter measured in psig units. This is another unit tha t always gives us pause in papers: we usually change this to atmospheres as a compromise, but the gauge par t usually leaves us wondering if we should not somehow add or subtract one from the number of atmospheres. Our hope is, however, tha t if we do it wrong enough times the authors themselves might feel impelled to make their own conversions, simply to preserve accuracy.

28 APPLIED OPTICS / Vol. 5, No. 1 / January 1966

The other universal failure of the electricals is in their symbols and units. Even though the I E E E has adopted the international convention on symbols, one finds in practice that a farad is still a Farad, f, instead of a farad, F . Cycles are almost never written per second, cps, or kc/sec, and decibel is still db instead of dB. We did notice, however, that giga and pico have pretty much re­placed kilomega and micromicro, so perhaps matters are im­proving.

We last discussed the present policy of this journal relative to the new prefixes in the editorial of October 1965. We received almost immediately and in the same mail two letters concerning this. The first took us severely to task: "Your editorial does not adequately recognize the accepted use of the Greek letter μ as the abbreviation for the prefix micro. The NBS has adopted the International System of Units for its publications. The Inter­national System of Units employs this usage. [See NBS News Bull. 48 (4), Apr. 1964]. The Style Manual of AIP accepts μ as the abbreviation for the prefix micro. (See AIP Style Manual, March 1963, p . 11). The Langley, Lewis, Ames, Electronics, and Marshall Centers of NASA have also adopted the Inter­national System, which assigns μ as the abbreviation for the prefix micro. (See NASA SP-7012.) I respectfully suggest tha t you, as the editor of a high quality technical journal, have an op­portunity to help clarify the communication of scientific and technical information by also adopting the International System of Units with its internationally recognized symbols and nomen­clature."

The other letter commented: "This is not a 'Letter to the Editor ' for publication, but I felt I must just drop you a line to thank you for your very sane comments about symbols and nomenclature in the October issue of APPLIED OPTICS. I hope this will preserve the use of micron and μ for the next ten years or so, by which time I shall have retired! I am all for a reason­able rationalisation of symbols, but well-established usage should not be jettisoned with too much abandon.

" I am disturbed, too at the thought of what these high-powered commissions (SUN, etc.) may be doing to our photometric and radiometric symbols. Provided you are sufficiently remote from a subject, it is easy to draw up a nice list of symbols which on paper looks very logical. But imposition from the top is rarely effective; these changes usually have to evolve from tough dis­cussion among the people who really use them and even then they are not readily adopted by everyone."

Let us hasten to remark, if it is not already clear, tha t we do endeavor in this journal to adhere to the AIP Style Manual and to the SI set of prefixes. The Greek letter μ (mu), when followed by any unit means micro, 10 - 6 , times that unit; thus μH means microhenry. Where we apparently differ is tha t in this journal (as in most of the journals dealing with optics and spectroscopy), the Greek letter μ if not followed by some other unit is also recognized as the symbol for the micron, 1 0 - 6 meter, which is also a unit in good repute, even in the International System, (and in the AIP 1963 Style Manual). We have a strong desire to clarify scientific communication; still it seems to us tha t a micron is just as clear as a micrometer.

JOHN N . HOWARD