Sir — Throughout the ages, historicaldocuments have been carved in stone,etched in clay, written on parchment andprinted on paper. Examination oftraditional documents requires merely theability to read and understand the languageor code in which they were written. Savingthem requires but a thoughtfully selectedrepository, with a security device if needed.But the term “read” has a completelydifferent connotation when referring to afloppy disk or a computer hard drive. So,whereas the Rosetta Stone only requiredinterpretation of the written key, today’sequivalents require all the correct operatingsystems and software applications.

Faced with these complexities, it is all tootempting to dump records in the recyclingbin. It is nothing short of terrifying tocontemplate the probable magnitude oflost records as yesterday’s electronicstorage devices become incompatible withtoday’s software applications.

These problems are most alarmingwhen considered in the context ofelectronic mail. Worldwide, the number ofcorporate mailboxes is projected to growfrom 131 million in 2001 to 225 million in2005; daily e-mail traffic is anticipated togrow from 9.7 billion pieces in 2000 tomore than 35 billion in 2005.

Little of this staggering volume istranslated to hard copy. Even formaldocuments are frequently discarded bysimply erasing them to avoid the tediumand expense of printing and archiving, onthe erroneous assumption that previousiterations are of no value. The threat to theexistence of hard-copy records of e-mailwill become more acute as youngergenerations become less culturally andeducationally attuned to their importancefor the preservation of historical records.

A perfect electronic world should notrequire hard copies of e-mail (or any otherelectronic document). E-technologyshould have addressed this problem as itevolved. But as individuals, institutionsand corporations have continually‘upgraded’, it has become moreproblematic to preserve e-documentsbecause formats, servers and institutionalIT policies change. The US NationalArchives has recently acknowledged thelack of robust e-mail archiving solutions,but has determined that long-term storageof electronic communications must beindependent of these variables (seewww.archives.gov/records_management).

Institutional policies also negativelyaffect long-term retention of e-mail. Withlimits of hard-drive space on mail servers,

institutional users are routinely faced withthe requirement to cleanse mailboxes. Thepen may be mightier than the sword, but asingle mouse-click can destroy products ofinestimable value.

The ease and simplicity of e-mail hasaltered the fundamental psychology ofcommunication — and of confidentiality.Most of us are oblivious to the reality thate-communication violates the confiden-tiality intrinsic to conversations: e-mailrecords (even deleted ones) can be sub-poenaed by courts of law. Other people’scomputers can easily be used to send orreceive e-mail, or to access the Internet.The potential for violations of confiden-tiality and for impersonation is all tooobvious, and examples of ‘e-fraud’ abound.

Even in honest use, the immediacy of e-mail breeds poor communication andcan rapidly escalate conflict. The facilenature of the medium encourages a lack of

sensitivity, and the false assumption thatsuch communication is private andconfidential can lead to situations such asthat of the recovery of e-mails questioningthe safety of the US space shuttle’s re-entrywritten days before the recent disaster.

Electronic communication is surelyhere to stay. Its simplicity and enormousspeed will ultimately send other modes ofcommunication close to extinction. But ITsolutions to the many problems it bringsare long overdue. Most serious is thepotential for the loss of records that mayhave immense historical value. For a start,academic (and other) institutions shouldrequire hard copies of certain categories ofelectronically generated information to bekept — with appropriate authentication.Errol C. Friedberg, Herbert K. Hagler,Kevin J. LandDepartment of Pathology, University of TexasSouthwestern Medical Center, Dallas, TX 75390, USA

correspondence

NATURE | VOL 423 | 19 JUNE 2003 | www.nature.com/nature 801

How e-mail raises the spectre of a digital Dark AgeRecords can be wiped out by a click of the mouse or rendered unreadable by upgrades.

Britannica: source of apassion for physicsSir — In his obituary of US physicist JulianSchwinger (Nature 370, 600; 1994), DavidS. Saxon wrote: “He once remarked that hehad been reading straight through theEncyclopaedia Britannica and when he cameto the letter P and to physics, that was it.”

In another memorial article, Paul C.Martin and Sheldon L. Glashow wrote“Armed with the 11th edition of theEncyclopaedia Britannica and the booksand journals in nearby libraries, Schwingerset himself apart from the establishment ofteachers, textbooks and assignments.”(Physics Today 48 (10), 40–46; 1995).

These descriptions raised my interest inthe contents of the famous 11th edition ofthe Encyclopaedia Britannica (1910), whichalso influenced the physicist FreemanDyson profoundly (see S. S. SchweberQED and the Men Who Made It: Dyson,Feynman, Schwinger, and Tomonaga 479;Princeton Univ. Press, 1994).

After examining this edition, I found tomy surprise that ‘physics’ is not an entryword. This is particularly strange as thisedition was published a decade and a halfafter the great discoveries that marked thebeginning of modern physics. In contrast,both ‘chemistry’ and ‘physiology’ are entrywords, with many depictions of these twosciences. Was Schwinger’s account of hisearly commitment to physics perhapseither a joke or a fable?

Of course, many entry words regarding

the science of physics were included andembedded in different volumes of theEncyclopaedia Britannica, so one couldwell believe that young Schwinger learntphysics from the entire set. Min-Liang Wong Department of Veterinary Medicine, College ofVeterinary Medicine, National Chung-HsingUniversity, Taichung 402, Taiwan

Britannica: which editioninspired Schwinger?Sir — Regarding Julian Schwinger’s storyof finding his subject by reading throughthe Encyclopaedia Britannica and stoppingat ‘Physics’: an entry entitled ‘Physics’appeared in every edition, beginning with the first in 1768, until the 8th(1852–60). In the 9th (1875–89) it wasreplaced with ‘Physical Sciences’ (by JamesClerk Maxwell), from a paper “Remarkson the classification of the physicalsciences”. ‘Physics’ as an entry title did not appear in the 11th or 12th, but it did appear in the 13th (1926), and in the modern sense, whereas previously it was an alternative name for ‘naturalphilosophy’ or ‘the science of nature’. Theauthor was Robert Andrews Millikan. The12th edition was actually the 11th with somesupplementary volumes, as was the 13th. Anita WolffSenior Editor, Encyclopaedia Britannica,310 South Michigan Avenue, Chicago, Illinois 60604, USA

© 2003 Nature Publishing Group