Chapter LIV

contains extracts from Castianus in Geoponic. Græc.,

Marbodeus and Rhenius, the interpreter of Dionysius.

In 1560 there was established at Naples, by the versatile Giam. della Porta, the first Academy of Sciences--Academia Secretum Naturæ--to which were admitted only those who had contributed to the advancement of medicine or to scientific studies in general (“Science,” December 19, 1902, p. 965).

REFERENCES.--Libri, “Hist. des Sc. Mathém.” Vol. IV. pp. 108–140, 399–406; Houzeau et Lancaster, Vol. II. p. 229; The Fourth Dissertation of the “Encycl. Brit.,” p. 624; Sarpi, at A.D. 1632; Poggendorff, “Geschichte der Physik,” 1879, pp. 133, 273–274; “Encycl. Brit.,” the article on “Optics”; “Journal des Savants” for September 1841.

=A.D. 1575–1624.=--Boehm--Böhme--Behmen (Jacob), a mystical German writer, known as the theosophist _par excellence_, is the author of “Aurora,” etc. (1612), “De Tribus Principiis” (1619) and of many other treatises, which were reprinted under the title of “Theosophia Revelata,” and which contain his many very curious observations concerning astrology, chemistry, theology, philosophy and electricity.

REFERENCES.--“Notice sur J. Boehm,” La Motte-Fouqué, 1831; “Notes and Queries” for July 28, 1855, p. 63; Ninth “Britan.,” Vol. III. p. 852; J. Ennemoser, “History of Magic,” Vol. II. pp. 297–328.

=A.D. 1576.=--Norman (Robert), a manufacturer of compass needles at Wapping, is the first who determined the _dip or inclination_ to the earth of the magnetic needle in London, by means of a dipping needle (inclinatorium) of his own making. Five years later (1581) Norman publishes a pamphlet “The Newe Attractive, containing a short discourse of the Magnes or Lodestone, and amongest other his vertues, of a newe discouered secret, and subtill propertie concernyng the Declinyng of the Needle, touched therewith, under the Plaine of the Horizon ...” from which is taken the following:

“Hauing made many and diuers compasses and using alwaies to finish and end them before I touched the needle, I found continuallie that after I had touched the yrons with the stone, that presentlie the north point thereof woulde bend or decline downwards under the horizon in some quantitie; in so much that to the flie of the compass, which was before levell, I was still constrained to put some small piece of ware on the south point and make it equall againe ...” (Weld, “History of the Royal Society,” 1848, Vol. II. p. 432).

In the fourth chapter of his work, Norman describes the mode of making the particular instrument with which he was enabled to establish the first accurate measurement of the dip “which for this citie of London, I finde, by exact obseruations to be about 71 degrees 50 mynutes.”

Whewell thus alludes to several investigations in the same line:

“Other learned men have, in long navigations, observed the differences of magnetic variations, as Thomas Hariot, Robert Hues, Edward Wright, Abraham Kendall, all Englishmen: others have invented magnetic instruments and convenient modes of observation such as are requisite for those who take long voyages, as William Borough, in his book concerning the variation of the compass; William Barlo, in his ‘Supplement’; Robert Norman, in his ‘Newe Attractive.’ This is that Robert Norman (a good seaman and an ingenious artificer) who first discovered the _dip_ of magnetic iron” (“Enc. Metr.,” p. 738; read also paragraph 366 of J. F. W. Herschel’s “Prelim. Disc.,” 1855).

In Book I. chap. i. of Gilbert’s “De Magnete,” he says that Norman posits a point and place toward which the magnet looks but whereto it is not drawn: toward which magnetized iron, according to him, is collimated but which does not attract it. He alludes again to this “respective point” (Book IV. chaps. i. and vi.), saying that Norman originated the idea of the “respective point” looking, as it were, toward hidden principles, and held that toward this the magnetized needle ever turns, and not toward any attractional point: but he was greatly in error, albeit he exploded the ancient false opinion about attraction. Gilbert then proceeds to show how this theory is proved by Norman. The original passage in Norman’s “Newe Attractive” (London, 1581, Chap. VI) is as follows:

“Your reason towards the earth carrieth some probabilitie, but I prove that there be no _Attractive_, or drawing propertie in neyther of these two partes, then is the _Attractive_ poynt lost, and falsly called the poynt _Attractive_, as shall be proved. But because there is a certain poynt that the needle alwayes respecteth or sheweth, being voide and without any _Attractive_ propertie: in my judjment this poynt ought rather to bee called the poynt _Respective_.... This poynt _Respective_, is a certayne poynt, which the touched needle doth always _Respect_ or shew....”

For the means of determining the _dip or inclination_, see “English Ency.”--Arts and Sciences--Vol. VIII. p. 160.

We have thus far learned that the _declination or variation_ was alluded to by Peter Peregrinus (A.D. 1269) in the Leyden MS.; that Norman was the first to determine the _dip or inclination_, and we shall, under the 1776 date, find that Borda determined the third magnetic element called the _intensity_.

In 1581 appeared “The newe attractive ... a discours of the variation of the cumpas ... made by W. B(orough).” This was followed, in 1585 and in 1596, by “The newe Attractive ... newly corrected and amended by M. W. B.,” also, in 1614, by “The New Attractive, with the application thereof for finding the true variation of the compass, by W. Burrowes.”

Norman is also the author of “The safegarde of Saylers, or Great Rutter ... translated out of Dutch ... by R. Norman,” 1590, 1600, 1640.

REFERENCES.--Noad, “Manual of Electricity,” London, 1859, p. 525; Gassendi, at A.D. 1632; Humboldt, “Cosmos,” 1859–1860, Vol. I. p. 179; Vol. II. pp. 281, 335; Vol. V. p. 58; Geo. Hartmann, A.D. 1543–1544; “Nature,” Vol. XIII. p. 523; Walker, “Magnetism,” p. 146, and, for a photo reproduction of the title-page to the 1581 edition as well as a copy of its contents, see G. Hellmann “Neudrucke ...” 1898, No. 10; also Sidney Lee, “Dict. of Nat. Biogr.,” Vol. XLI. p. 114, and William Whiston (1667–1752), “The Longitude and Latitude, discovered by the Inclinatory or Dipping Needle,” London, 1721.

=A.D. 1580.=--The celebrated naturalist Li-tchi-tchin, who finished his _Pen-thsao-Kang-Mou_ towards the end of 1580, says: “If the loadstone was not in love with iron it would not attract the latter.” Eight and a half centuries before, about the year A.D. 727, the same allusion had been made by Tchin-Thsang-Khi in his “Natural History” (Klaproth, “Lettre à M. de Humboldt ...” Paris, 1834, p. 20).

=A.D. 1580.=--In Parke’s translation of the “History of the Kingdom of China,” written by Juan G. de Mendoza, a Spanish missionary sent to the Chinese Empire by Philip II, appears the following (Vol. II. p. 36): “The Chinos doo gouerne their ships by a compasse deuided into twelue partes and doo vse no sea cardes, but a briefe description of Ruter (Ruttier--Routier--direction book) wherewith they do nauigate or saile.”

=A.D. 1581.=--Burrowes--Borough--Burroigh (William), “a man of unquestionable abilities in the mathematiques,” Comptroller of the English navy in the reign of Elizabeth, who has been alluded to as Robert Norman, is the first in Europe to publish well authenticated observations upon the magnetic variation or declination made by him from actual observation, while voyaging between the North Cape of Finmark and Vaigatch (Vaygates). These are recorded at length in his little book dedicated to “the travaillers, seamen and mariners of England” and entitled “A Discourse of the Variation of the Cumpas, or Magneticall Needle. Wherein is Mathematically shewed, the manner of the observation, effects, and application thereof, made by W. B. And is to be annexed to The Newe Attractive of R. N. 1581 (London).”

At pp. 7 and 8 of his “Terrestrial and Cosmical Magnetism,” Cambridge, 1866, Mr. Walker gives extracts from the twelve chapters of Burrowes’ work which, “containing, as it does, the first recorded attempt at deducing the declination of the needle from accurate observations, must be considered as making an epoch in the history of terrestrial magnetism.”

REFERENCES.--Johnson, “New Univ. Encycl.,” 1878, Vol. III. p. 230, and the tables of the variations at pp. 274–275 of Vol. II. of Cavallo’s “Elements of Natural Philosophy,” 1825. See the photo reproduction of “A Discourse ...” 1596 ed. in G. Hellmann’s “Neudrucke ...” 1898, No. 10.

=A.D. 1585.=--Juan Jayme and Francisco Galli made a voyage from the Philippines to Acapulco, solely for the purpose of testing by a long trial in the South Sea a declinatorium of Jayme’s invention, from which M. de Humboldt says (“Cosmos,” 1859, Vol. V. p. 56) some idea may be formed of the interest excited in reference to terrestrial magnetism during the sixteenth century.

=A.D. 1586.=--Vigenere (Blaise de), in his annotations to Livy (“Les cinq premiers livres de Tite-Live,” Paris, 8vo, Vol. I. col. 1316) alludes to the possibility of communicating the contents of a letter through a thick stone wall by passing a loadstone over corresponding letters circumscribing the compass needle.

REFERENCES.--“Emporium of Arts and Sciences,” Vol. I. p. 302; Fahie, p. 20.

=A.D. 1589.=--Acosta (Joseph d’), learned Jesuit, who has been already mentioned under the A.D. 121 entry, says in Chap. XVII. lib. i. of his masterly “Historia Natural de las Indias” (“Histoire Naturelle et Moralle des Indes tant Orientalles qu’Occidentalles,” traduite par Robert Reynault Cauxois, 1598, 1606) that he is able to indicate four lines of no variation (instead of one only discovered by Columbus) dividing the entire surface of the earth: “foure poyntes in all the world, whereas the needle looked directly towards the North.” Humboldt remarks that this may have had some influence on the theory advanced, in 1683, by Halley, of four magnetic poles or points of convergence.

REFERENCES.--Humboldt, “Cosmos,” 1859–1860, Vol. I. pp. 66, 193, note; Vol. II. pp. 280, 281; Vol. V. p. 140.

=A.D. 1590.=--Cæsare (Giulio-Moderati), a surgeon of Rimini, observes the conversion of iron into a magnet by position alone. This effect was noticed on a bar which had been used as a support to a piece of brickwork erected on the top of one of the towers of the church of St. Augustine as is mentioned at the 1632 entry of Pietro Sarpi.

=A.D. 1597.=--Barlowe--Barlow (William)--who died May 25, 1625, and was Archdeacon of Salisbury--publishes his “Navigators’ Supply,” from which the following is extracted: “Some fewe yeares since, it so fell out that I had severall conferences with two East Indians which were brought into England by Master Candish (Thomas Cavendish, one of the great navigators of the Elizabethan Age) and had learned our language.... They shewed that in steade of our compas they (in the East Indies) use a magneticall needle of sixe ynches long ... upon a pinne in a dish of white _china_ earth filled with water; in the bottome whereof they have two crosse lines for the foure principall windes, the rest of the divisions being reserved to the skill of their pilots.”

Barlowe also published in 1613, 1616 and 1618 different editions of his work on the magnet, the full title of the last named being “Magneticall Advertisements or diuers pertinent obseruations and approued Experiments concerning the nature and properties of the Loadstone. Whereunto is annexed a briefe Discoverie of the idle Animadversions of Mark Ridley, Dr. in Physike upon this treatize.”[28] Therein (Preface to the reader), he speaks of “That wonderful propertie of the body of the whole earth called the magneticall vertue (most admirably founde out and as learnedly demonstrated by Doctor Gilbert, physitian vnto our late renowned soveraigne Queen Elizabeth of happy memory) is the very true fountaine of all magneticall knowledge. So that although certain properties of the loadstone were knowne before, yet all the reasons of those properties were vtterly vnknowne and never before revealed (as I take it) vnto the sonnes of man....” Just before the Preface appears the following letter which (as William Sturgeon remarks) affords a good idea of the opinion entertained by Gilbert of Barlowe’s talents in this branch of science: “To the Worshipfull, my good friend, Mr. William Barlow, at Easton by Winchester. Recommendations with many thanks for all your paines and courtesies, for your diligence and enquiring, and finding diuers good secrets, I pray proceede with double capping your Loadstone you speake of, I shall bee glad to see you, as you write, as any man. I will haue any leisure, if it were a moneth, to conferre with you, you haue shewed mee more,--and brought more light than any man hath done. Sir, I will commend you to my L. of Effingham, there is heere a wise learned man, a Secretary of Venice, he came sent by that State, and was honourably receiued by her Majesty, he brought me a lattin letter from a Gentleman of Venice that is very well learned, whose name is Iohannes Franciscus Sagredus, he is a great Magneticall man and writeth that hee hath conferred with diuers learned men of Venice, and with the Readers of Padua, and reporteth wonderfull liking of my booke, you shall haue a coppy of the latter: Sir, I purpose to adioyne an appendix of six or eight sheets of paper to my booke after a while, I am in hand with it of some new inuentions, and I would haue some of your experiments, in your name and inuention put into it, if you please, that you may be knowen for an augmenter of the art. So far this time in haste I take my leaue the XIII of February. Your very louing friend, W. GILBERT.”

Speaking of William Barlowe, Anthony à Wood says: “This was the person who had knowledge of the magnet twenty years before Dr. Will. Gilbert published his book of that subject, and therefore by those that knew him he was accounted superior, or at least equal, to that doctor for an industrious and happy searcher and finder out of many rare and magnetical secrets” (“Athenæ Oxonienses,” London, 1813, Vol. II. p. 375). Under heading of Gilbert, the “British Museum Catalogue of Printed Books,” 1888, has it that “Mag. Adv.” was compiled partly from “De Magnete.”

REFERENCES.--Mark Ridley, “Magn. Animad.,” 1617, p. xi; Cavallo, “Magnetism,” 1787, p. 46; A.D. 1302; Sidney Lee, “Dict. of Nat. Biogr.,” Vol. III. pp. 233–234; “La Grande Encycl.” (H. Lamisault), Vol. V. p. 430; Pierre Larousse, “Grand Dict. Univ. du xix^e siècle,” Paris, 1867, Vol. II. p. 239; Claude Augé, “Le Nouveau Larousse,” Vol. I. p. 738; “Wood’s Ath. Ox.” (Bliss), Vol. II. p. 375; Hœfer, “Nouv. Biogr. Univ.,” Vol. IV. p. 53; “Biogr. Britannica”; Hutton, “Mathem. Dict.”; “British Annual,” I.

=A.D. 1599.=--Wright (Edward), English mathematician, connected with the East India Company and author of the Preface to Gilbert’s original “De Magnete,” published in London “Die Havenvinding--The Haven-finding Art: Translation of Simon Stevinus’ ‘Portuum investigandorum ratio,’” in which is urged the advantage of keeping registers of the variations observed on all voyages. Thus, says Lardner, the _variation of the variation_ not only as to time, but as to place, had at this period begun to receive the attention of those engaged in navigation.

Wright constructed for Prince Henry a large sphere which represented the motion of the planets, moon, etc., and he predicted the eclipses for seventeen thousand one hundred years. He is said to have discovered the mode of constructing the chart which is known by the name of Mercator’s Projection.

Simon Stevinus, above mentioned, also called Stephanus--Simon of Bruges--was a most distinguished mathematician and physicist (1548–1628), and is alluded to by Edward Wright not only in the Preface to Gilbert’s “De Magnete” above referred to, but also in Book IV. chap. ix. of the latter work. The English translation of “Portuum investigandorum ratio” was afterwards attached to the third edition of Wright’s “Certaine errors in navigation detected and corrected.”

REFERENCES.--“English Cycl.,” Vol. VI. p. 834; “Biogr. Génér.,” Vol. XLIV. pp. 496–498; Larousse, “Dict.,” Vol. XIV. p. 1100; G. Hellmann, “Neudrucke ...” 1898, No. 10; “Chambers’ Encycl.,” 1892, Vol. IX., p. 725; “La Grande Encycl.,” Vol. XXX. pp. 489–490; Montucla, “Hist. des Mathém.,” Paris, An. VIII. Vol. II; Quetelet, also Van de Weyer, “Simon Stevin,” 1845; “Mémoires de l’Académie,” Paris, 1753, p. 275; Steichen, “Vie et Travaux de S. Stevin,” 1846; “Terrestrial Magnetism,” Vol. I. p. 153, and Vol. II. pp. 37, 72, 78.

=A.D. 1599.=--Pancirollus (Guido)--Panciroli (Gui)--already quoted at A.D. 121, further remarks: “The ancients sailed by the pole star, which they call _Cynosura_. The compass is believed to have been found at Amalfi, about 300 years ago by one Flavius. And this unknown fellow (if it was Flavius) hath deserved more than 10,000 Alexanders and as many Aristotles.... This single act hath improved knowledge and done more good to the world than all the niceties of the subtle schools.”

REFERENCES.--“History of Things Lost,” London, 1715, Vol. II. p. 338; Græsse, Vol. V. p. 117; also his biography in Larousse, “Dict. Univ.,” Vol. XII. p. 108, and in the “Dict. de Biographie,” Vol. II. p. 2012.

=A.D. 1600.=--Schwenter (Daniell), Professor of Oriental languages at Altdorff, describes, under the assumed name of Janus Hercules de Sunde, in his “Steganologia et Steganographia,” the means of communicating intelligence at a distance by employing two compass needles circumscribed with an alphabet, the needles being shaped from the same piece of steel, and magnetized by the same magnets.

Under caption “The First Idea of the Electric Telegraph,” the following appeared in the “Journal of the Franklin Institute,” Vol. XXI. 1851, p. 202: “In the number of the _Philosophical Magazine_ for May, 1850, I [N. S. Heineken] observe that Prof. Maunoir claims, for his friend Dr. Odier, the first idea of the electric telegraph. I herewith send you a translation of ‘How two people might communicate with each other at a distance by means of the magnetic needle,’ taken from a German work by Schwenter, entitled ‘Deliciæ Physico-Mathematicæ,’ and published at Nürnberg in 1636 ... upward of a century before the period alluded to by Prof. Maunoir. Indeed, Oersted’s grand discovery was alone wanting to perfect the telegraph in 1636. The idea, in fact, appears to have been entertained prior even to this date, for Schwenter himself quotes, at p. 346, from a _previous_ author.” This “previous author” is either Giambattista della Porta, mentioned at A.D. 1558, or Famianus Strada, who appears herein under the A.D. 1617 date.

The passage from Dr. Louis Odier’s letter relative to an electric telegraph is given at A.D. 1773 (see J. J. Fahie, “A History of Electric Telegraphy to the Year 1837,” London, 1884, pp. 21–22).

=A.D. 1600.=--Gilbert--Gilberd--Gylberde (William), of Colchester (1544–1603), physician to Queen Elizabeth and to James I of England, justly called by Poggendorff “The Galileo of Magnetism,” publishes his _“De magnete, Magneticisque Corporibus, et de Magno magnete tellure; Physiologia nova, plurimis et argumentis et experimentis demonstrata,”_ to which he had given “seventeen years of intense labour and research”[29] and which he dedicates “alone to the true philosophers, ingenuous minds, who not only in books but in things themselves look for knowledge,” and wherein the phenomena of electricity are first generalized and classified.

This great work is subdivided into six books, which respectively treat of the loadstone, of magnetic movements (_coitio_), of direction (_directio_), of variation (_variatio_), of declination (_declinatio_), and of the great magnet, the earth[30] of circular movement (_revolutio_).

## BOOK I

After Gilbert has given in this Book an account of ancient and modern writings on the loadstone,[31] he indicates exactly what the latter is, where found, its different properties, and, having introduced us to his _terrella-microge_, or little earth[32]--a globular loadstone, showing that it has poles answering to the earth’s poles, he tells us all about iron ore, its natural and acquired poles, the medicinal virtues attributed by the ancients to iron as well as to the loadstone; and he ends this First Book with the announcement that loadstone and iron ore are the same, that iron is obtained from both, like other metals from their ores, and that all magnetic properties exist, though weaker, both in smelted iron and in iron ore; furthermore, that the terrestrial globe is magnetic and is a loadstone; and that just as in our hands the loadstone possesses all the primary powers (forces) of the earth, so the earth, by reason of the same potencies, lies ever in the same direction throughout the universe.

## BOOK II

The justly famous Second Book contains Gilbert’s electrical work and, as is generally known, the second chapter thereof is the earliest ever published on electricity. We are here introduced to Gilbert’s _versorium_--a rotating needle electroscope[33]--and are given the results of his many experimental observations[34] and the opinions of others relative to magnetic coition or attraction. We find, throughout the whole of the second chapter, the first systematic study of amber, with an interesting list of electrics and the recognition of a group of anelectrics--non-electrics. After pointing out the different kinds of attractions admitted by Galen and other ancient writers, we are told that:

“Only feeble power of attraction is possessed by some electrics (all which have their own distinct effluvia) in favouring dry atmosphere: observable in midwinter while the atmosphere is very cold, clear and thin, when the electric effluvia of the earth offer less impediment and electric bodies are harder--that these bodies then draw, as well, all metals, wood, leaves, stones, earths, even water and oil, in short, whatever things appeal to our senses or are solid.

“All bodies are attracted by electrics, save those which are afire or flaming or extremely rarefied.

“Very many electric bodies do not attract at all, unless they are first rubbed. An ordinary piece of amber does not attract by heat, even when brought to the flaming point, but it attracts by friction, without which latter few bodies give out their true natural electric emanation and effluvium. By friction, the amber is made moderately hot and also smooth; these conditions must in most cases concur; but a large polished piece of amber or of jet attracts even without friction, though not so strongly; yet, if it be carefully brought nigh to a flame or a red coal, it does not attract corpuscles; further, the sun’s heat heightened by means of a burning-glass imparts no power to amber, for it dissipates and spoils all the electric effluvia. Again, flaming sulphur and burning sealing-wax (of lac) do not attract.

“The loadstone, though susceptible of very high polish, has not the electric attraction. The force does not come through the lustre proceeding from the rubbed and polished electric; for the vincentina, diamond and pure glass attract when they are rough. Effluvia that attract but feebly when the weather is clear produce no motion at all when it is cloudy. For the effluvium from rock crystal, glass, diamond--substances very hard and very highly compressed--there is no need of any notable outflow of substance. Such an electric as sound cypress-wood, after a moment’s friction, emits powers subtle and fine, far beyond all odours; but sometimes an odour is also emitted by amber, jet, sulphur, these bodies being more readily resolved; hence it is that, usually, they attract after the gentlest friction because their effluvia are stronger and more lasting.

“Rock crystal, mica, glass, and other electric bodies do not attract if they be burned or highly heated, for their primordial humour is destroyed by the heat, is altered, is discharged as vapour. All bodies that derive their origin principally from humours and that are firmly concreted attract all substances whether humid or dry; but bodies consisting mostly of humour and not firmly compacted by nature, wherefore they do not stand friction but either fall to pieces or grow soft or are sticky, do not attract corpuscles.

“Electrical movements come from the matter (_materia_) but magnetic from the prime form (_forma_). Moist air blown from the mouth, moisture from steam, or a current of humid air from the atmosphere chokes the effluvium. But olive oil that is light and pure does not prevent it; and, if a sheet of paper or a linen cloth be interposed, there is no movement. But loadstone, neither rubbed nor heated, and even though it be thoroughly drenched with liquid, and whether in air or water, attracts magnetic bodies, and that though solidest bodies or boards or thick slabs of stone or plates of metal stand between.

“Electrics attract all things save flame and objects aflame, and thinnest air ... for it is plain that the effluvia are consumed by flame and igneous heat ... yet they draw to themselves the smoke from an extinguished candle; and, the lighter the smoke becomes as it ascends, the less strongly is it attracted, for substances that are too rare do not suffer attraction.”

This