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active agent Albertus Magnus astrolabe attracts the south Augustinian axis azimuth becomes Brunetto Latini called the tramontane capsules CHAPTER determined direction dish elongated piece ence Engineering Epistola float on water floating lodestone Foucaucourt Gasser Gilbert's De Magnete Guido Guinicelli Guyot de Provins heavens in accord Hence homogeneous Htstoria Orientalis instrument ished Jacques de Vitry joined known letter of Peregrinus Leyden lode LODESTONE ATTRACTS lodestone pointing lodestone selected Lucera Magnetic declination Magnetica manner Maricourt mariners marked meridian Mineralibus mond Lully move the ruler natural Neckam needle or iron north and conversely north and south north end north pole Paris passive subject perpetual motion PETRUS PEREGRINUS Picard pivots place the stone pole attracts pole star properties receive their virtue repelled Roger Bacon rounded sailor south end south pole stone attracts stone be moved Taisnier teeth thirteenth century touch the south translation treatise Tresor des Sciences Wheeler Collection
Page 37 - The sailors, as they sail over the sea, when in cloudy weather they can no longer profit by the light of the sun, or when the world is wrapped in the darkness of night, and they are ignorant whither the ship's course is directed, touch a needle to the magnet ; the needle will then whirl around in a circle until, when its motion ceases, its point is directed to the north.
Page viii - A pendant chain we hold of steely rings Dropt from the stone — the stone the binding source — Ring cleaves to ring and owns magnetic force : Those held above, the ones below maintain, Circle 'neath circle downward draws in vain Whilst free in air disports the oscillating chain.
Page viii - Magnet's region where it grew.) Its viewless, potent, virtues men surprise; Its strange effects they view with wondering eyes, When without aid of hinges, links or springs, A pendent chain we hold of steely rings, Dropt from the stone ; the stone the binding source. Ring cleaves to ring, and owns magnetic force ; Those held superior those below maintain; Circle 'neath circle downward draws in vain, While free in air disports the oscillating chain.
Page 30 - By means of this instrument you can direct your course towards cities and islands and any other place wherever you may wish to go by land or sea, provided the latitude and longitude of the places are known to you.
Page xii - I know of only one person who deserves praise for his work in experimental philosophy, for he does not care for the discourses of men and their wordy warfare, but quietly and diligently pursues the works of wisdom. Therefore, what others grope after blindly, as bats in the evening twilight, this man contemplates in all their brilliancy because he is a master of experiment.
Page xii - ... pursues the works of wisdom. Therefore, what others grope after blindly, as bats in the evening twilight, this man contemplates in all their brilliancy because he is a .master of experiment. Hence, he knows all...
Page xii - Hence, he knows all natural science whether pertaining to medicine and alchemy, or to matters celestial and terrestrial. He has worked diligently in the smelting of ores as also in the working of minerals ; he is thoroughly acquainted with all sorts of arms and implements used in military service and in hunting, besides which he is skilled in agriculture and in the measurement of lands. It is impossible...
Page viii - Utensilibus, what is perhaps the earliest reference to the mariner's compass that we have. Albertus Magnus, the Dominican (1193-1280), in his treatise De Mineralibus, enumerates different kinds of natural magnets and states some of the properties commonly attributed to them ; the minstrel, Guyot de Provins, in a famous satirical poem, written about 1208, refers to the directive quality of the lodestone and its use in navigation, as do also Cardinal de Vitry in his Historia Orientialis (1215-1220),...
Page xiii - INTRODUCTORY in the measurement of lands. It is impossible to write a useful or correct treatise in experimental philosophy without mentioning this man's name. Moreover, he pursues knowledge for its own sake; for if he wished to obtain royal favor, he could easily find sovereigns who would honor and enrich him." This last statement is worthy of the best utterances of the twentieth century. Say what they will, the most ardent pleaders of our day for original work and laboratory methods cannot surpass...
Page 38 - AVhen the sea is dark and hazy, That one sees neither star nor moon, Then they put a light by the needle, And have no fear of losing their way ; The point turns towards the star ; And the mariners are taught To follow the right way. It is an art which cannot fail.