PROGRESS OF SCIENCE TO 1450 A.D. 187 



ALCHEMY. What astrology was to astronomy, alchemy was 

 to chemistry ; viz. the crude and often magic-working predecessor. 

 The search for such will o' the wisps as the " philosopher's stone," 

 the "elixir of life," "potable gold" and the "transmutation of 

 elements," is probably as old as human history. The ancients 

 seem to have dabbled in it, the Arabs to have been devoted to it, 

 and the men of the Middle Ages, and even of the fourteenth and 

 fifteenth centuries, to have spent much time upon it. Alembics 

 and receivers, "Moors' Heads" and "Moors' Noses," calci- 

 fication, distillation, and the like typify interesting and by no 

 means fruitless gropings after the real composition of things. 

 The names of Albertus Magnus, Bernard of Treviso, Eck of Salz- 

 burg, and Basil Valentine are some which have come down to us 

 as most important at this time, and as we read of the prepara- 

 tion of the " spirits of salt " (hydrochloric acid), the calcification 

 (oxidation) of mercury, etc., we realize that their labors, though 

 often misdirected, were the prelude to better things. 



THE MARINER'S COMPASS. The loadstone was certainly known 

 to antiquity as a stone having the power of attracting and 

 carrying a load of iron, but its directive property seems to have 

 been first recognized and used for guidance on land or sea by the 

 Chinese, since according to Humboldt, Chinese ships navigated 

 the Indian Ocean with the magnetic needle in the third century of 

 our era. The Arabs are also credited with its invention and use, 

 as stated in the preceding chapter. The first reference to it in 

 Christian Europe is said to be in a poem by Guyot of Provence, 

 dated 1190, while references are also made to the compass in 

 works of the thirteenth century. One of these runs : 



No master mariner dares to use it lest he should be suspected of 

 being a magician; nor would the sailors venture to go to sea under 

 the command of a man using an instrument which so much appeared 

 to be under the influence of the powers below. 



It is probable, however, that the compass was first made 

 commonly useful to western Europe early in the fourteenth 

 century, by Flavio Gioja, a native of Amalfi, a small port 



