A. the Invention of the Telescope

A. THE INVENTION OF THE TELESCOPE

GALILEO DID NOT INVENT THE TELESCOPE, AND HE NEVER CLAIMED TOHAVE DONE SO

AS WITH MOST INVENTIONS OR DISCOVERIES THAT ORGINATE IN THE CRAFT TRADITIONS, THE EXACT DATE OF THE INVENTION OF THE TELESCOPE CANNOT BE SET

NOR IS THE IDENTITY OF THE INVENTOR CERTAIN

THE STANDARD ACCOUNT HAS HANS LIPPERHEY, A DUTCH LENS-GRINDER, APPLYING FOR A PATENT ON THE NEW OPTICAL INSTRUMENT IN 1608

ON SEPTEMBER 25TH, 1608, A LETTER RECOMMENDING A PATENT FOR THENEW INSTRUMENT WAS WRITTEN AND SENT TO THE HAGUE

IT REPORTED A MIRACULOUS INSTRUMENT: THE INVENTOR CLAIMED -- QUOTE -- "TO HAVE A CERTAIN DEVICE BY MEANS OF WHICH ALL THINGS AT A VERY LARGE DISTANCE CAN BE SEEN AS IF THEY WERE NEARBY, BY LOOKING THROUGH GLASSES WHICH HE CLAIMS TO BE A NEW INVENTION" (VAN HELDEN, P. 20)

OTHER SCHOLARS HAVE ARGUED THAT THE TELESCOPE WAS ACTUALLY INVENTED MUCH EARLIER, AROUND 1590, BY AN ITALIAN

WHILE STILL OTHERS PLACE THE DATE OF ITS INVENTION AFTER 1600 BUT BEFORE 1608 AND BACK IN HOLLAND

PERHAPS MORE IMPORTANT THAN ESTABLISHING THE FACTS OF PIORITY IN THE INVENTION OF THE TELESCOPE IS AN UNDERSTANDING OF THE CONDITIONS THAT GAVE RISE TO WHAT -- IN ALL LIKELIHOOD -- WERE MULTIPLE INDEPENDENT DISCOVERIES

IN THE MIDDLE AGES THERE HAD BEEN THE IDEA THAT A COMBINATIONOF LENSES AND MIRRORS COULD PERFORM AMAZING OPTICAL FEATS OF ILLUSION AS WELL AS GENUINE MAGNIFICATION

AS EARLY AS THE 13TH CENTURY, ROGER BACON HAD CLAIMED THAT WITH CERTAIN TYPES OF LENSES - QUOTE - "FROM AN INCREDIBLE DISTANCE WE MIGHT READ THE SMALLEST LETTER, AND NUMBER GRAINSOF DUST AND SAND"

AND ELSEWHERE IT WAS WRITTEN OF HIM THAT HE HAD A "GLASSE THATHE MADE IN OXFORD, IN WHICH MEN MIGHT SEE THINGS THAT WERE DONE IN OTHER PLACES"

SEVERAL AUTHORS, WRITING AFTER HIM, REPEATED AND EXTENDED SUCH CLAIMS

BUT THESE DESCRIPTIONS MUST BE UNDERSTOOD AS PART OF THE WISH-LIST OF THOSE WHO WERE INTERESTED IN THE BLURRY BOUNDARY BETWEEN OPTICS AND MAGIC

THESE AUTHORS WERE WORKING PRIMARILY IN A LITERARY AND PHILOSOPHICAL TRADITION, AND THEIR SPECULATIONS WERE NOT CONCERNED WITH THE PRACTICAL MATTERS OF GRINDING LENSES

AND, OF COURSE, BEFORE THERE CAN BE TELESCOPES, THERE MUST BE LENSES

LENSES REQUIRE GLASS-MAKERS AND LENS-GRINDERS

THESE ARE THE CRAFTS OF THE URBAN ARTISAN CLASS; AND ARTISANS DO NOT TYPICALLY DEPEND UPON MAGICIANS FOR THEIR LIVELIHOOD, BUT ON THE MARKET

WHERE DOES ONE FIND A MARKET FOR LENSES? IN COLLEGE TOWNS

SPECTACLE LENSES MADE FROM GLASS WERE INVENTED IN THE LAST FEW DECADES OF THE 13TH CENTURY

FARSIGHTEDNESS, THE VISUAL IMPAIRMENT THAT MOST FREUQUENTLY AFFECTS PEOPLE PAST THE AGE OF FORTY, CAN BE CORRECTED WITH CONVEX LENSES

EARLY CONVEX EYE-GLASSES, DATING FROM THIS SAME PERIOD, WERE ABOON TO AGING SCHOLARS SINCE IT SUBSTANTIALLY EXTENDED THEIR READING LIFE

THE OTHER MOST TYPICAL IMPAIRMENT IS, OF COURSE, NEARSIGHTEDNESS, WHICH CAN BE CORRECTED WITH CONCAVE LENSES

ACCORDING TO ONE STUDY, NEARSIGHTEDNESS HAS AN INCIDENCE OF ABOUT 2% IN AN ILLITERATE OR SEMI-LITERATE POPULATION, BUT THE PERCENTAGE REACHES MORE THAN 32% AMONG UNIVERSITY STUDENTS

THUS, EVEN AMONG HISTORICAL POPULATIONS, WE MAY ASSUME A REASONABLY HIGH CORRELATION BETWEEN STUDYING -- READING AND WRITING -- AND THE NEED FOR CONCAVE EYE-GLASSES

IT IS IMPORTANT TO NOTE THAT CONCAVE LENSES ARE HARDER TO GRIND THAN CONVEX, AND CONCAVE SPECTACLES FOR MYOPES WERE NOT INVENTED UNTIL AROUND 1450 -- JUST IN TIME FOR THE COMING FLOOD OF SQUINTY-EYED STUDENTS READING ALL THOSE FRESHLY-PRINTED TEXTBOOKS

THUS, WITH THE GROWTH OF UNIVERSITIES AFTER THE 12TH CENTURY AND ESPECIALLY WITH THE EXPLOSION IN BOOK PRODUCTION AFTER THE INVENTION OF PRINTING IN 1450, THERE WAS A LARGE AND STEADY DEMAND FOR SPECTACLES IN 16TH-CENTURY UNIVERSITY TOWNS

AND THAT'S WHERE GLASS-MAKERS AND LENS-GRINDERS SET UP SHOP

THEREFORE, BY ABOUT 1525, THERE EXISTED THROUGHOUT EUROPE A SMALL BUT WIDE-SPREAD CRAFT TRADITION, CAPABLE OF GRINDING BOTH CONVEX AND CONCAVE LENSES

BY 1600 THERE HAD BEEN A STEADY IMPROVEMENT IN THE GLASS-MAKING AND LENS-GRINDING INDUSTRY; AND SPECTACLE-MAKERSTYPICALLY HAD A VARIETY OF BOTH TYPES OF LENSES IN THEIR SHOP

HOWEVER, TO MAKE A TELESCOPE OF THE SORT GALILEO USED, ONE NEEDS A CONCAVE LENS OF FAIRLY STRONG CURVATURE -- SOMETHING NOT EASILY ACHIEVED BEFORE 1600 -- AND A WEAKLY CURVED CONVEX LENS

[DIAGRAM]

AROUND 1600 THE WEAKEST CONVEX LENS FOUND IN SPECTACLE MAKERS' SHOPS HAD FOCAL LENGTHS OF ABOUT 18 TO 21 INCHES

AND THE STRONGEST CONCAVE LENSES HAD FOCAL LENGTHS OF AROUND 7 INCHES

THUS, BY BRINGING THESE TWO LENSES INTO THE PROPER ALIGNMENT, ONE COULD PRODUCE A TELESCOPE CAPABLE OF A THREE-FOLD MAGNIFICATION

BUT HAVING LENSES OF THE PROPER SHAPE AND STRENGTH LYING AROUND THE LOCAL SPECTACLE SHOP DOES NOT MAKE A TELESCOPE, EITHER

WHAT IS STILL MISSING IS THE INCENTIVE TO EXPLORE THE POSSIBILITIES OF UNUSUAL -- EVEN IMPRACTICAL -- COMBINATIONS OF LENSES

WHAT IS MISSING IS A BRIDGE BETWEEN THE THEORETICAL AND THE PRACTICAL -- WHAT IS NEEDED, IN OTHER WORDS, IS THE IDEA THAT WONDERFUL THINGS CAN BE DONE BY COMBINING LENSES

THE FINAL PRECONDITION FOR THE INVENTION OF THE TELESCOPE -- AND NOT MERELY THE PLAYING WITH LENSES -- CAME FROM LATE 16TH-CENTURY MAGI -- THAT IS, PRACTITIONEERS OF RENAISSANCE MAGIC

REFERENCES TO THE POWERS OF LENSES AND MIRRORS BECOME INCREASINGLY FREQUENT AFTER 1550, ESPECIALLY IN THE WRITINGS OF 'MAGI' LIKE JOHN DEE IN ENGLAND AND GIOVANBAPTISTA DELLA PORTA IN ITALY

THE EARLIEST DISCUSSIONS ARE FANCIFUL AND UNREALIZABLE, LIKE THOSE OF ROGER BACON IN THE 13TH CENTURY

BUT THESE ACCOUNTS SOON SHOW THAT THEIR AUTHORS WERE BEGINNING TO EXPERIMENT WITH REAL LENSES AND TAKING A CLOSER LOOK AT THE ACTIVITIES OF LENS-GRINDERS -- THEIR SPECULATIONS WEREGAINING A FOUNDATION IN PRACTICE

HOWEVER, NONE OF THESE ACCOUNTS REFER TO CONCAVE LENSES, SO IT IS VERY UNLIKELY THAT ANYONE BEFORE 1600 HAD ACTUALLY EXPERIMENTED WITH WHAT MIGHT BE CONSIDERED A TELESCOPE

THE INVENTION OF THE TELESCOPE COULD ONLY COME ABOUT WHEN THE ASPIRATIONS TO PRODUCE A WONDERFUL GLASS MERGED WITH THEMUNDANE ACHIEVEMENTS OF LENS-GRINDERS

AND THIS HAPPENED IN THE FIRST DECADE OF THE 17TH CENTURY

HOWEVER, THE CRUCIAL THING IN AN INVENTION, IS THE REALIZATION OF ITS POTENTIAL BY THE 'INVENTOR' AND THE DISSEMINATION OF THE KNOWLEDGE OF ITS POTENTIAL TO AN INTERESTED AUDIENCE

AND THAT TOOK PLACE AFTER HANS LIPPERHEY'S PATENT APPLICATION IN 1608

BECAUSE AN INSTRUMENT CAPABLE OF MAKING DISTANT THINGS SEEMNEAR HAD AN OBVIOUS MILITARY APPLICATION, NEWS OF LIPPERHEY'S INVENTION SPREAD VERY QUICKLY THROUGH DIPLOMATIC AND MILITARYCHANNELS

TELESCOPES WERE FOR SALE IN PARIS BY APRIL 1609, IN MILAN BY MAY, AND IN VENICE AND NAPLES BY AUGUST

WHILE OTHERS SAW THE TELESCOPE AS A NEW MILITARY INSTRUMENT, GALILEO SAW IT AS SOMETHING ELSE

IT WAS HIS TICKET TO THE BIG-TIME