AIDS TO EXTENDED VISION

New Zealand Herald, Volume LXXV, Issue 23115, 13 August 1938, Page 1 (Supplement)

AIDS TO EXTENDED VISION

By MATANGA

Enter the Microscope

YEARS ago two men in Christchurch spent the best part of a pleasant afternoon debating as to which, the telescope or the microscope, served more impressively and deeply the human mind. One, a lawyer, contended for the telescope, with its revelations of a stupendous, majestic universe; the other, zealously studious of natural science, put the case for the microscope, unfolder of another universe, seemingly infinite and as full of wonder. At the end, the question was left happily unsettled; a fitting conclusion, because the telescope and the microscope had a common, fraternal origin. That thorough discussion was recalled by one of the friendly disputants when he read this week of the contriving of a super-microscope, magnifying 30,000 diameters, instead of the present maximum of 2000. What new revelations may not be in store, waiting in the realm of the infinitely little! The ancients knew scarcely anything of that realm. Although they were acquainted with the mechanism of vision and did prodigies of work with the naked eye, such aids to sight as even spectacles were unknown to them. Spectacles, by the way—there is a hint of marvels in their name—date back only to about i2SS, when a Florentine, Salvino delgi Armati, made the first, keeping his secret for profit until it was found out and charitably published •• by Alexander Spina, a monk of Pisa, shortly before the inventor's death in 131 7 . Many people have seen in the British Museum a remarkable piece of rock crystal, oval in shape, fiat 011 one side and slenderly convex on the other. It bears undeniable witness to having been ground to that form, and Sir --David Brewster believed it was a lens designed for the purpose of magnifying. Its Interest lies in the indisputable fixing of its date as not later than 721-705, B.C. But Brewster's opinion has been exploded, chiefly by the discovery of cloudy streaks, these so present in irregular layers that they would fatally obstruct optical use. These striae were just the sort of thing to make the crystal attractive as a decorative boss. "Burning Glasses'' Even the ancients' use of crystal globes filled with water for various purposes cannot substantiate an earlier claim. Pliny the elder and others describe them as used for cauterisation by focussing the sun's rays and for starting a fire, but -they say nothing about their employment for intentional magnifying. Seneca, to be sure, says that "letters though small and indistinct are seen enlarged and more distinct through a globe of glass filled with water," and that "fruit appears larger when seen immersed in a vase of glass. But all '.-he - concluded Vtas that objects seen through water appeared larger than they really were. How near to losing altogether his chance of charging high prices Salvino degli Armati came is also a matter of history. Just before his invention a good Franciscan, gifted in science, .Roger Bacon of Ilchester, discovered . the principle of convergent lenses. But his discovery went for nothing, in spite of its. inclusion in his "Opus Majus" of 1276, for strnnge care was taken to keep his knowledge from others. Among the marvellous things recounted in his great work was the efficacy of crystal lenses, "an instrument useful to old men and those whose sight 13 weakened, who in such a way will be able to see the letters sufficiently enlarged, however small they are." Yet he so encountered the hatred of some of his contemporaries that they kept him in prison for many years and afterwards shut him up in religious confinement until he died at nearly eighty. His scientific writings were hidden until Samuel Jebb made them known in 1733. A Testimonial Roger Bacon's words of prophetic comfort for thf> aeed are strikingly duplicated in the earliest known manuscript reference to spectacles, dating from Florence in 1299. "I find myself so pressed by age," writes one who was probably among Salvino degli Armati's monopolised customers, "that I can neither read nor write without those glasses they call spectacles, lately invented, to the great advantage of poor old men when their sight grows weak." Once begun, the progress from such simple contrivances to the microscope was only a matter of time. Quickly upon the heels of the telescope it came, in the opening years of the seventeenth century. The exact date is difficult to fix, but to Galileo must go the chief credit, although the ingenuity of a Dutchman, Drcbbel. is also entitled .to honourable mention. Galileo experimented until he produced, it seems in 1610, a compound instrument, adapted from the Dutch telescope. He called it an occhialino. Then, amid the multiplicity of his scientific interests, he neglected it; forgot it, one might almost say, because somewhere between the end of 1619 and the middle of October, 1622, while he was preparing his "Saggiatore," he spoke . thus to O'ratio -Grassi Salonense —an anagram for Lotario Sarsi Segensano: "I might toll Sarsi something new if anything now could be told him. Let him take any substance whatever, _ be it stone, or wood,'or metal, and holding in the sun examine it attentively, sd'. 1 he will see all the colours distributvl in the most* minute particles, and he will make use of a telescope arraPged so that one can see very near -°bjeets he will see far more distinctly what I say." Beginning of Surprises More interesting still, as closer to *he story of Galileo's invention of the microscope, is Girolamo Aleandro's description of the quandary of a cardial to whom Drebbel had sent two incomprehensible contrivances; they were shown to Galileo, who immediately recognised them as microscopes and exPlained their use. That was in 1624. Already in that year, it is now Known. Galileo had made a microscope himself and sent it to the Duke of Ijavaria. "I was yesterday evening at the house of our Signer Galileo, who J'ves near the Madelena." writes Faber to Cesi. "Ho gave the Cardinal di poller a magnificent eye-glass for the •Lhiko of Bavaria. I saw a fly which bignor Galileo himself showed me. I was astounded, and told Signor Galileo that he was another creator, in that, ae shows things that until now we did not know had been created." tli the following year another wrote that "a mite appeared as-large as a P e a, so that one can distinguish its «ead, its feet, and its hair—a thing »mch seemed incredible to many until they had witnessed it with admiration." ■wv u reve " a ti° ns were a beginning to • ® lc » there seems to be no end.