Free You Could Look It Up by Jack Lynch Page B

alternative traditional medicine in the Middle East turn to Avicenna for practical guidance. The Qanun , in the words of one historian, “might be called the most famous medical textbook ever written, and it was retranslated and reprinted in Europe down to the middle of the seventeenth century… . Of all the great characters of history Avicenna has an especial interest to medical men.” 14

    Bald and Avicenna probably lived within a few decades of each other, but they never knew of each other’s existence. England and Persia were, for all practical purposes, on opposite sides of the world. But they were engaging in the same enterprise, trying to incorporate the best thinking about medical practice from ancient and foreign sources into their own domestic system. For Bald that meant Latin and Byzantine prescriptions; for Avicenna it meant ancient Greek medical theory. And both chose the form of the reference book in which to advance their syncretic conception of medicine, because it was the most reliable way to translate theory into practice. It is a valuable reminder that encyclopedias can be the site of important cross-cultural dialogue.

CHAPTER 8
    ADMIRABLE ARTIFICE
    Computers before Computers
Henry Briggs
Arithmetica logarithmica
1624
  
Johannes Kepler
Tabulæ Rudolphinæ
1627

    “Math class is tough!” So declared the Teen Talk Barbie doll in 1992 , enraging a generation of feminists who despaired of finding children’s toys that did not reinforce harmful gender stereotypes. But Barbie was right: math is hard.
    If it is not quite so tough for us today, that is because we are spoiled by tiny computers that go with us everywhere. In the age of the feature-packed mobile phone, we need not even divide a restaurant bill by hand. A computer with more computing power than the entire Apollo program had at its disposal is there to give us an answer as quickly as we can press the buttons. But it has not always been so. For most of history, all calculations were done by hand, because there was no other way to do them.
    Books containing page after page of digits may be the most referency of all reference books in their unsuitability for reading through. Dictionaries, encyclopedias, even the phone book can make for entertaining browsing: there is always the hope of coming across amusing names. But it is hard to read more than a few lines in a table of numbers without feeling one’s energy waning, and even the most devoted reference book enthusiast will have trouble with this:

1201
3,07954,30074,0290
1234
3,09131,51596,9721
         36,14602,6382

         35,17978,9847
1202
3,07990,44676,6672
1235
3,90166,69575,9568
         36,11596,7313

         35,15131,5712
1203
3,08026,56273,3985
1236
3,09201,84707,5280
         36,08595,8196

         35,12288,7632
1204
3,08062,64869,2181
1237
3,09236,96996,2912
         36,05599,8908

         35,09450,5497

    and so on, for 396 folio pages. 1 Hardly gripping reading. And yet such unreadable tables shaped the modern world.
    The tables are designed as labor-saving devices: they take the place of long calculations done by hand, allowing us to look up the answers rather than arriving at them manually. In American restaurants, for instance, where a tip of 15 to 20 percent of the bill is customary, many people keep a small laminated card in their wallets on which are 15%, 18%, and 20% tips on various totals. These tip charts are descendants of old-fashioned “ready reckoners,” printed tables that go back centuries and were especially common in countries without metric measurement or decimal coinage. 2 A mercer selling 8½ yards of cloth at 4s. 3d. a yard would be grateful for any shortcut in figuring that the total was £1 16s. 1½d. John Mayne’s Socius Mercatoris; or, The Merchant’s Companion (1674) was there to answer the question, as were almanacs and books like Harris’s Pocket Journal .

    As handy as