Chapter XVI: Book I: chap. i. Therein, he says that Baptista Porta, who has made the (1)

seventh book of his “Magia Naturalis” a very storehouse and repertory of magnetic wonders, knows little about the movements of the loadstone and never has seen much of them, and that a great deal of what he has learned about its obvious properties, either through Messer Paolo, the Venetian, or through his own studies, is not very accurately noted and observed.

In the introduction to the 1658 edition of his “Natural Magick,” Porta admits that he gained some knowledge of Sarpi, who, says he, is of all men he ever knew the most learned and skilful and the ornament and splendour not only of Venice or of Italy, but of the entire world. Bertelli refers (“Memor. sopra P. Peregrino,” p. 24, note) to P. Garbio’s “Annali di Serviti,” Lucca, 1721, Vol. II. pp. 263, 272, 274, and to Fra Fulgenzio Micanzio’s “Life of Sarpi,” Helmstat--Verona, 1750, in which it is stated that not only Porta but likewise a celebrated _ultramontane_ studied magnetism under him. Garbio asks: “Could this _ultramontane_ be Gilbert of Colchester?”

By Griselini (“Vita de Fra P. Sarpi”--memoria anecdote--Lausanne, 1760), Paolo is said to have written a treatise on the magnet and to have therein recorded many observations, including the earliest mention that magnetic properties are destroyed by fire.

Bertelli--whose afore-named memoir we must confine ourselves to, as it is more satisfactory than are the accounts elsewhere given--makes mention that he has had in his possession, by courtesy of Sig. Giuseppe Valentinelli, the Royal Librarian of the Marciana at Venice, copy of a manuscript (Cod. CXXIX, classe 2, MS. Ital.) containing a brief comparison of Sarpi’s magnetic researches with those of Musschenbroek. This manuscript is again alluded to by Bertelli (Memor., p. 88) wherein it is said that lines 5–38 of the first column, p. 170, are headed “Observations of F.P.S. on the loadstone, collated with P. Musschenbroek’s Researches,” and embrace five paragraphs translated as follows:

1. The author had first tried the action of one magnet on
another without entering into the question of calculation,
but modern authors have, in view of the observations made,
endeavoured to discover a method of computing magnetic forces
in any proportion to the distances, and in the same better
regulated systems they have discovered the cause to be uncertain
(or varying) owing to the contemporaneous action of magnetic
repulsion.

2. He was acquainted with the well-known action of the
magnet on iron, but he understood--as even at this day
some understand--that it was caused by the atmosphere. New
experiments have made us seriously doubt this. He did not pay
attention to the proportion of the magnetic forces as compared
with the distances of iron, to the discovery of which the
efforts of present philosophers are directed but in vain. He
saw, however, that the facility or difficulty of attraction
depends upon the size of the iron (maximum and minimum).

3. He was not ignorant of the direction of the magnet and of
iron rubbed with the magnet towards certain quarters of the sky
when he mentions the new discovery of the poles in the magnet,
and the variation of the magnetized needle, from the Northern or
the Southern quarters, but he did not know a greater number than
two poles found in the magnet, the variation of the declination,
or, I should rather say, the uncertainty of the variation and
the different inclinations of the needle at different places on
the earth.

4. Almost all the experiments referred to by Academies, with
reference to the action of one piece of iron on another piece
of iron, magnetized and not magnetized, and with regard to the
changes of forces which arise from the various inflections of
iron, have been sufficiently sketched out by F. P. S.

5. The magnetic effects acquired by an old piece of iron
continually exposed to the air have also been alluded to. Now,
however, natural philosophers have observed that this iron
exposed for a length of time in the magnetic meridian points
with greater readiness to the above-mentioned quarters. They
have, moreover, ascertained that iron when heated and afterwards
cooled in water is more sensitive to magnetization: which is
directly opposed to the opinion of F. P. S.

Bertelli further remarks that, from information given in the manuscript, it is seen that Sarpi was at that time acquainted with the greater number of the magnetic phenomena referred to by Porta, and developed by Gilbert, viz.:

1. The reciprocal action of magnets;

2. The action of magnets on iron;

3. The manifestation of magnetic activity about the poles
(sphere of action or field of force);

4. The _Maximum_ and the _Minimum_ of the attractive
force of magnets on iron, according to the size of the latter;

5. The inversion of polarity which may arise in the
magnetization of needles--(but not the corresponding
poles--the magnetic variation or declination--Petrus
Peregrinus, A.D. 1269--yet not the variation of the
variation--Henry Gellibrand, A.D. 1635--nor the dip or
inclination--Robert Norman, A.D. 1576).

6. The magnetic properties acquired by iron constantly exposed
to the air.

After detailing the observations of Giulio Cesare Moderati, Filippo Costa (Costæus) of Mantua, Ulysses Aldrovandi, Francesco Acoromboni, Luigi Matteini, Father Garzoni and Father Cabæus concerning the magnetized ironwork of the belfry of the church of St. Augustine at Arimini (the parochial church of St. John the Baptist, which at that time, 1586, belonged to the monks of St. Augustine) and relative to the iron rail in the belfry of the tower of St. Laurence at Rome, Bertelli says: “From all that precedes, we gather at all events, that the fact of the spontaneous magnetization of iron was well known in Italy before Sarpi, Porta and Gilbert. This, Gilbert, and still better Cabæus, explained as the influence of terrestrial magnetism. However, with regard to the observations of the needle’s deviation made by Father Garzoni at Rome, we can, without having attributed it, as does Cabæus, to the magnetization of pieces of iron concealed in its wall, explain it, as is done in the new and important experiments of the illustrious professor Silvestro Gherardi, who attributes it to the magnetic polarity of the _Mattoni_ [bricks] in the structure itself.”

It is said by Humboldt (“Cosmos,” 1849, Vol. II. p. 718, note) that this observation, the first of the kind, was made on the tower of the church of the Augustines at Mantua (Mantova) and that Grimaldi and Gassendi were acquainted with similar instances (instancing the cross of the church of St. Jean, at Aix, in Provence), in geographical latitudes where the inclination of the magnetic needle is very considerable. Some writers give Gassendi’s observation as occurring during 1632 (see Rohaulti, “Physica,” 1718, Par. III. cap. 8, p. 399; or, Rohault’s “System of Nat. Phil.,” 1728, p. 176).

“As the iron cross of an hundred weight upon the Church of St. John in Ariminum, or that load-stoned iron of Cæsar Moderatus, set down by Aldrovandus” (Sir Thomas Browne, “Pseudodoxia Epidemica,” 1658, p. 66).

Consult “Lettera dell’Eccel. Cavallara.,” Mantova, 1586, for a detailed account of this discovery, made January 6, of the last-named year. The iron rod supported a brick ornament in the form of an acorn, and stood on a pyramid at the summit of the belfry of the church of St. Augustine (Cabæus, “Philos. Magn.,” p. 62; “Ulysses Aldrovandi, Patr. Bonon ... Barthol. Ambros ...” Lib. i, cap. 6, p. 134).

For the account given by Aldrovandi of the Arimini observation and for references to Browne’s “Pseudodoxia Epidemica,” as well as to Boyle’s “Experiments,” see p. 53 of the valuable “Notes on the ‘De Magnete’ of Dr. William Gilbert,” by Silvanus P. Thompson, attached to the English translation of the original 1600 edition, which was so attractively produced by the Gilbert Club during the year 1900. Dr. Thompson further gives, at the page following (54), additional references to examples of iron acquiring strong permanent magnetism from the earth.

REFERENCES.--Biography of Sarpi in the “Encycl. Brit.,” ninth
edition, Vol. XXI. pp. 311–313; F. Micanzio, “Vita de F.
P. Sarpi,” Verona, 1750; Rev. Alex. Robertson, “Fra Paolo
Sarpi--the greatest of the Venetians,” 1894; Hallam, “Intro.
to Lit.,” 1839, Vol. II. p. 464; U. Aldrovandi, “Musæum
Metallicum,” 1648, p. 134; Tiraboschi, “Storia della Lettera,”
Modena, 1794, Vol. VI. part ii. p. 506; Sarpi’s Complete Works,
first published at Helmstat, 1750; Fabroni, “Vitæ Italorum,”
Pisa, 1798; Giovini, “Vita,” Brussels, 1836; “Engl. Cycl.,”
Biography, Vol. IV. pp. 695–697; Larousse, “Dict. Univ.” Vol.
XIV. pp. 230–231; “History of the reign of Charles the Fifth,”
by Wm. Robertson and Wm. H. Prescott, Philadelphia, 1883, Vol.
III. p. 68; “Dict. Hist. de la Médecine,” N. F. J. Eloy, Mons,
1778, Vol. IV. pp. 180–181; “The Atlantic Monthly,” New York,
January and February, 1904, wherein the author, Andrew D. White,
ranks Sarpi with Machiavelli and Galileo; Libri, “Hist. des Sc.
Mathém.” Paris, 1838, Vol. IV. p. 214, note.

=A.D. 1632.=--Gassendi (Pierre), an eminent French savant, professor at the Royal College of France, “ranked by Barrow among the most eminent mathematicians of the age, and mentioned with Galileo, Gilbert and Descartes,” discovers that a part of the iron cross of the Church of St. Jean at Aix possesses all the properties of a loadstone after being struck by lightning and lying in one position a certain length of time. Gilbert mentions, “De Magnete,” 1600, Book III. chap. xii.) that the fact of magnetism being imparted to an iron bar by the earth was first ascertained by examining the rod upon the tower of the church of St. Augustine at Arimini (Sir Thomas Browne, “Pseud. Epidemica,” London, 1650, p. 48; U. Aldrovandi, “Musæum Metallicum,” Milan, 1648, p. 134).

In the “Vie de Pierre Gassendi,” par le Père Bougerel de l’Oratoire, Paris, 1737, p. 14, it is related that during the month of September 1621, while promenading about three leagues’ distance from Aix in a village named Peynier, he observed a light in the heavens to which he gave the name of _aurora borealis_, as much on account of its location as by reason of its resemblance to the light which precedes the rising of the sun.

From the “History of the Royal Society,” by C. R. Weld, 1848, Vol. II. p. 430, is taken the following, communicated by Humboldt:

“The movement of the magnetic lines, the first recognition of which is usually ascribed to Gassendi, was not even yet conjectured by William Gilbert; but, at an early period, Acosta, ‘from the information of Portuguese navigators,’ assumed four lines of no declination upon the surface of the globe.... In the remarkable map of America appended to the Roman edition of the Geography of Ptolemy in 1508, we find, to the north of Gruentland (Greenland), a part of Asia represented and the magnetic pole marked as an insular mountain. Martin Cortez, in the ‘Breve Compendio de la Sphera’ (1545), and Livio Sanuto, in the ‘Geographia di Tolomeo’ (1588), place it more to the south. Sanuto entertained a prejudice, which, strange to say, has existed in later times, that a man who should be so fortunate as to reach the magnetic pole (_Il calamitico_) would then experience _alcun miracoloso stupendo effecto_” (“Cosmos,” translated under the superintendence of Col. Sabine, Vol. II. p. 280). In a footnote to the Otté translation of Humboldt, 1859, Vol. V. p. 58, it is stated that _calamitico_ was the name given to the instruments in consequence of the first needles for the compass having been made in the shape of a frog.

In Gilbert’s “De Magnete,” allusion is made to Martinus Cortez, Book I. chap. i., also Book III. chap. i. and Book IV. chap. i.,[43] and to Livio Sanuto in Book I. chap. i., also in Book IV. chaps. i. and ix. In these several passages, Gilbert tells us that Martinus Cortez holds the loadstone’s seat of attraction to be beyond the poles, and he states the views of other writers in this respect, citing more particularly T. de Bessard (author of “Le Dialogue de la Longitude”), Jacobus Servertius (who wrote “De Orbis Catoptrici”), as well as Robert Norman, Franciscus Maurolycus, Marsilio Ficino, Cardan, Scaliger, Costa and Petrus Peregrinus (M. J. Klaproth, “Lettre à M. le Baron de Humboldt,” Paris, 1834, pp. 16–17, 37).

REFERENCES.--Enfield, “Hist. Phil.,” Vol. III. p. 430; “Le
Cosmos” for May and June 1859, containing a very interesting
series entitled, “Les Armées Météores”; Lardner, Vol. II. p.
113; Humboldt, “Cosmos,” 1859–1860, Vol. II. p. 335, and Vol. V.
pp. 146–153; Julius Cæsar at A.D. 1590; Houzeau et Lancaster,
Vol. II. p. 146; “Mém. de l’Acad. Royale des Sciences,” Vol. X.
p. 737; “Phil. Hist. and Memoirs of the Royal Acad. of Sc.,”
Vol. II. p. 281; “Geschichte der Mathematik,” Vol. IV. p. 474.

=A.D. 1632.=--Galileo (Galileo Galilei), Italian philosopher and mathematician, publishes his celebrated “Dialogo sopra i due massimi sistemi del mondo tolemaico e copernicano,” 4to, Fiorenza, from p. 88 of which is extracted the following passage:

_Sagredus_: “You remind me of a man who offered to sell me a secret for permitting one to speak, through the attraction of a certain magnet needle, to someone distant two or three thousand miles, and I said to him that I would be willing to purchase it, but that I would like to witness a trial of it, and that it would please me to test it, I being in one room and he being in another. He told me that, at such a short distance, the action could not be witnessed to advantage; so I sent him away and said that I could not just then go to Egypt or Muscovy to see his experiment, but if he would go there himself I would stay and attend to the rest in Venice.”

This _Sagredus_ (Iohannes Franciscus), or Sagredo (Giovanni Francisco), besides being “a great magneticall man,” was a noble Venetian, even a doge, and had represented his country as ambassador at several courts. We read in Mr. Conrad W. Cooke’s very able article on William Gilbert of Colchester, originally printed in London “Engineering,” that this same _Sagredus_ was the intimate friend of Galileo, and that, together with the powerful Sarpi, he used the whole might of his name and influence to protect the great philosopher and mathematician from the attacks of the clerical party. Pietro Sarpi, otherwise known as Father Paul, was, as already shown, a most illustrious Venetian scholar, who attained great proficiency in the medical and physiological sciences as well as in mathematics and in natural philosophy. _Sagredus_ made several meritorious researches in magnetism, and, while on a voyage to Aleppo, ascertained the declination of the magnetic needle at that place. As a tribute to the scientific attainments of _Sagredus_, Galileo gave his name to one of the characters in his “Systema Cosmicum,” and many references to the work by William Gilbert are put into the mouth of _Sagredus_.

In further illustration of Galileo’s appreciation of Gilbert, the following is quoted from the great astronomer’s own writing: “I extremely admire and envy the author of ‘De Magnete.’ I think him worthy of the greatest praise for the many new and true observations which he has made, to the disgrace of so many vain and fabling authors, who write not from their own knowledge only, but repeat everything they hear from the foolish and vulgar, without attempting to satisfy themselves of the same by experience; perhaps that they may not diminish the size of their books” (Drinkwater’s “Life of Galileo”).

Galileo had also published, in 1630, the first edition of his “I discorsi e demonstrazioni ...” which Lagrange considers to be Galileo’s most substantial title to scientific glory.

REFERENCES.--Galileo’s Biography in “Engl. Cycl.,” Vol. III.
pp. 13–17; Miller, “Hist. Phil. Illust.,” London, 1849, Vol.
III. p. 203, note; Nelli, “Vita,” 1793; Libri, “Hist. des Sc.
Math.,” Paris, 1838, Vol. IV. pp. 157–294, 473–484; Houzeau et
Lancaster, “Bibliog. Générale,” Vol. I. part i. pp. 655–657
for an analyzation of the works of Galileo, also Vol. II. pp.
137–145, 1576–1578; Wm. Whewell, “Phil. of the Ind. Sc.,”
London, 1840, Vol. II. pp. 379–383; Guillaume Libri, “Histoire
des Sc. Math.,” Halle, 1865, Vol. IV. pp. 157–302, and the
notes; “Journal des Savants” for September and October 1840,
for March and April 1841, for July to November 1858, for
September 1868 and for October 1877; “Geschichte der Mathem.,”
Vol. IV. pp. 4, 173, etc.; Larousse, “Dict.,” Vol. VIII. p. 954;
“La Grande Encycl.,” Vol. XVIII. pp. 383–385; “Biog. Gén.,”
Vol. XI. pp. 252–267; Fabroni (A.), “Vitæ Italorum,” 1778–1805,
also “Elogi d’Illustri Italiani,” 1786–1789; likewise the very
numerous entries concerning Galileo’s history, his Opponents,
Supporters and School, which appear at pp. 331–357, Part I. of
Libri’s “Catalogue,” published in 1861. Consult also “Galileo,”
by Ed. S. Holden, in the “Popular Sc. Monthly” for January,
February, May and June 1905; “Bibliot. Brit.,” Vol. XVI. N.S.,
1821, pp. 3–21, 79–100, for an account of the life of Galileo
by M. G. B. Clément de Nelli; “Journal des Sçavans,” Vol. LXX.
for 1721, p. 350 in his “Saggiotore”; “Imperial Dictionary of
Universal Biography,” published by Wm. McKenzie, London, pp.
536–539, giving an account of Galileo’s other discoveries.

=A.D. 1635.=--Delambre (J. B. J.) (1749–1822), professor of astronomy at the Royal College of France, refers (Vol. II. p. 545 of his “Histoire de l’Astronomie Ancienne,” 1817) to the mention made in “Procli Diadochi Paraphrasis Ptolem.,” lib. iv. “de siderum effectionibus,” 1635, p. 20, of the notion long current, especially along the shores of the Mediterranean, “that if a magnetic rod be rubbed with an onion, or brought into contact with the emanations of the plant, the directive force will be diminished, while a compass thus treated would mislead the steersman.”

REFERENCES.--Humboldt, “Cosmos,” 1859, Vol. V. p. 156, also
the entry at A.D. 1653. See likewise Whewell, “Hist. of the
Ind. Sc.,” Vol. I. pp. 442, 443, 447, and the biography in the
Supplement of the “English Cyclopædia,” pp. 539–541; “Journal
des Savants,” for April 1828.

=A.D. 1635.=--Gellibrand (Henry), prominent English mathematician, professor of geometry and the successor of Edmund Gunter (A.D. 1624), in the chair of astronomy at Gresham College, publishes his discovery of the _secular variation of the declination_. The credit of this discovery has been by many given to John Mair. The _diurnal and horary variation_ was found by Graham in 1722, and the _annual variation_ was discovered by Cassini, 1782–1791.

Gellibrand’s discovery is published in a small quarto pamphlet entitled “A discourse mathematical on the variation of the magneticall needle--together with the admirable diminution lately discovered,” and is the result of his study of the observations made by Burrough and Gunter as well as of observations made by himself, all showing that the north-east of the needle was gradually moving to the westward.

Mention has already been made of the fact that the _variation of the variation_ was at this period attracting the attention it deserved, and it is worth while giving here an account of the discovery in the author’s own words:

“Thus, hitherto, according to the Tenents of all our Magnetical Philosophers, we have supposed the variations of all particular places to continue one and the same. So that when a Seaman shall happly return to a place where formerly he found the same variation, he may hence conclude he is in the same former longitude. For it is the assertion of Mr. Dr. Gilbert’s _Variatio unicuiusq; loci constans est_, that is to say, the same place doth always retaine the same variation. Neither hath this assertion, for ought I ever heard, been questioned by any man. But most diligent magneticall observations have plainely offered violence to the same, and proved the contrary, namely, that the variation is accompanied with a variation.”

=A.D. 1637.=--Bond (Henry), Professor of Mathematics in London, and who appears in one of his treatises as “a famous teacher of the art of navigation,” is the author of the “Seaman’s Kalendar ... with a discovery of the ... secret of longitude ...” of which other editions appeared during 1640 and 1696.

This was followed by many papers on the variation (the most important of which are to be found in _Phil. Trans._ for 1668, 1672, 1673) and, during 1678 by “The Longitude not found, or an answer to a treatise written by H. B. ...” This treatise was in a sixty-five page pamphlet which had been issued by Mr. Bond’s father during 1676, under caption: “The Longitude Found; or a treatise shewing an easie and speedy way, as well by Night as by Day, to find the Longitude, having but the Latitude of the Place and the Inclination of the Magneticall Inclinatorie Needle ...” wherein he explains his discovery of the progress of the deviation of the compass and foretells the variations for London, 1663 to 1716. This treatise led to the controversy with Peter Blackborrow (Beckborrow), the title to whose published work reads: “The Longitude not found: or an answer to a treatise written by H. Bond, senior, shewing a way to find the longitude by the magnetical inclinatory needle: wherein is proved that the longitude is not nor cannot be found by the magnetic inclinatory needle.”

As Humboldt remarks, the resulting controversy, together with Acosta’s view that there were four lines of no variation which divided the earth’s surface, may, as already stated, have had some influence on the theory advanced, in 1683, by Edmund Halley, of four magnetic poles or points of convergence (“Cosmos,” 1859–1860, Vol. I. p. 193, note; Vol. II. pp. 280–281, note; Vol. V. p. 58; also Humboldt’s “Examen Critique de l’Histoire de la Géographie,” Vol. III. p. 60. See likewise the _Phil. Trans._ for October 19, 1668, p. 790, and for 1673, Vol. VIII. p. 6065, also following abridgments: Hutton, Vol. II. p. 78, and Lowthorp Vol. II. p. 610).

REFERENCES.--Walker, “Magnetism,” Chap. I; John Pell, “Letter of
Remarks on Gellibrand’s Math. Disc.,” 1635; “Annales de Chimie
et de Physique,” Mars 1902, Vol. XXV. pp. 289–307; Humboldt,
“Cosmos,” 1859, Vol. V. pp. 61, 116; Whewell, “Hist. of the
Ind. Sc.,” 1859, Vol. II. p. 219; G. Hellmann, “Neudrucke von
Schriften,” No. 9; Baddam’s abridgments of the _Phil. Trans._,
1739, Vol. IV. p. 102.

=A.D. 1641.=--Wilkins (John), Bishop of Chester in the reign of Charles II, publishes the first edition of “Mercury, or the secret and swift messenger, showing how a man, with privacy and speed, may communicate his thoughts to a friend at any distance.”[44]

In the above, he thus alludes to the possibility of making a contrivance similar to our modern phonograph: “There is another experiment ... mentioned by Walchius, who thinks it possible so to contrive a trunk or hollow pipe that it shall preserve the voice entirely for certain hours or days, so that a man may send his words to a friend instead of his writing. There being always a certain space of intermission, for the passage of the voice, betwixt its going into these cavities and its coming out; he conceives that if both ends were seasonably stopped, while the sound was in the midst, it would continue there till it had some vent. _Huic tubo verba nostra insusurremus, et cum probe munitur tabellario committamus_, etc. When the friend to whom it is sent shall receive and open it, the words shall come out distinctly, and in the same order wherein they were spoken. From such a contrivance as this [saith the same author] did Albertus Magnus make his Image, and Friar Bacon his Brazen Head, to utter certain words.”

In the eighteenth chapter, he makes suggestions for “a language that may consist of only tunes and musical notes, without any articulate sound.”

He had previously described a novel mode of telegraphing by the use of only three torches (or lights), to designate the twenty-four letters of the alphabet. These letters were, according to the plan of Joachimus Fortius, to be placed in three classes of eight each. One torch indicated Class I, two torches Class II, three torches Class III, and the number of the letter was shown by the number of times a torch was elevated.

Bishop Wilkins also described a method of telegraphing by means of two lights attached to long poles, which, he says, “for its quickness and speed is much to be preferred before any of the rest.” To interpret messages at long distances, he suggested the use of the then newly invented telescope; which he called “Galileus his perspective.”

REFERENCES.--The third edition of above-named work, Chap. XVII.
pp. 71, 72, also the fifth edition of Wilkin’s “Mathematical
Magick,” London, 1707, Chap. XIII. pp. 147–150, “concerning
several attempts of contriving a perpetual motion by magnetical
virtues.” Likewise Whewell, “Hist. of the Ind. Sc.,” 1859, Vol.
I. pp. 332, 395; Mendoza, “Tratado de Navegacion,” Vol. II.
p. 72; Alex. Chalmers, “Gen. Biog. Dict.,” London, 1811, Vol.
XXXII. pp. 74–82.

=A.D. 1641.=--Kircher (Athanasius), a German writer on physical and mathematical science (1601–1680), member of the Order of Jesuits, possessed of immense erudition and believing in the magnetism of all things, speaks in his “Magnes sive de arte magnetica” (Book II. pt. iv. chap. v.), of the recently advanced idea of being able to correspond at short distances by employing two spherical vessels bearing the letters of the alphabet, each of the letters having suspended from it a magnetized figure attached to a vertical wire.

He likewise alludes to Gellibrand’s discovery, A.D. 1635, of which he was informed by John Greaves, the eminent English mathematician, and he communicates a letter received from the learned French philosopher, le Père Marin Mersenne, containing a distinct account of the same.

His definition of universal magnetism, according to Madame Blavatsky, is very original, for he contradicted Gilbert’s theory that the earth was a great magnet. He asserted that, although every particle of matter and even the intangible “powers” were magnetic, they did not themselves constitute a magnet. _There is but one Magnet in the universe, and from it proceeds the magnetization of everything existing._ This magnet is, of course, what the Kabalists term the central Spiritual Sun, or God.... He demonstrates the difference between mineral magnetism and zoömagnetism, or animal magnetism, and says that the sun is the most magnetic of all bodies.... It imparts the binding power to all things falling under its direct rays (“Isis Unveiled,” pp. 208–210).

Another Jesuit, Jacobo Grandamico (1588–1672), published in 1645, “Nova demonstratio immobilitatis terræ petita ex virtute magnetica,” wherein he shares fully the views of Niccolas Cabæus, Athanasius Kircher, Vincentus Leotaudus and others of the same Order relative to the earth’s magnetism (Larousse, “Dict.,” Vol. VIII. p. 1445).

REFERENCES.--“Journal des Sçavans” pour 1665 et 1666, pp.
519–525, 571–578; “Nouveau Larousse,” par Claude Augé, Paris,
Vol. V. p. 485; “Salmonsen ... konversationsleksikon,” 1900, p.
480; Van Swinden, “Recueil,” 1784, Vol. II. pp. 352, 361, 394,
and the different works named in Ronalds’s “Catalogue,” pp.
266–267; ninth ed. “Encycl. Brit.,” Vol. XIV. pp. 93–94.

=A.D. 1644.=--Digby (Sir Kenelme), the very famous Englishman to whom allusion has already been made under the B.C. 600–580 entry, publishes, in Paris, “Two Treatises, in the one of which the Nature of Bodies: in the other, the nature of Man’s Soule is looked into: in Way of Discovery of the Immortality of Reasonable Soules.”[45] In a chapter of this work, entitled “Of the lodestone’s generation and its particular motions,” appears the following interesting reference to Gilbert’s work and reputation: “But to come to experimentall proofes and obseruations vpon the loadstone by which it will appeare that these causes are well esteemed and applyed, we must be beholding to that admirable searcher of the nature of the loadstone, Doctor Gilbert: by means of whom and of Doctor Haruey, our nation may claim euen in this latter age as deserued a crowne for solide Philosophicall learning as for many ages together it hath done formerly for acute and subtile Speculations in Diuinity. But before I fall to particulars, I thinke it worth warning my Reader, how this great man arriued to discouer so much of Magneticall Philosophy; that he, likewise, if he be desirous to search into nature, may, by imitation, advance his thoughts and knowledge that way. In short, then, all the knowledge he gott of this subject was by forming a little loadstone into the shape of the earth. By which meanes he compassed a wonderful designe, which was to make the whole globe of the earth maniable; for he found the properties of the whole earth in that little body; which he therefore called a Terrella, or little earth; and which he could manage and trye experiences vpon att his will. And, in like manner, any man that hath an ayme to aduance much in naturall sciences, must endeauour to draw the matter he inquireth of, into some such modell, or some kinde of manageable methode; which he may turne and winde as he pleaseth. And then lett him be sure, if he hath a competent vnderstanding, that he will not misse of his marke.”

REFERENCES.--“The Private Memoirs of Sir Kenelme Digby,
Gentleman of the Bedchamber of King Charles I,” London, 1827;
“Dict. of Nat. Biog.,” Vol. XV. pp. 60–66; “New Gen. Biog.
Dict.,” London, 1850, Vol. XI. p. 390; “Gen. Biog. Dict.” of
Alex. Chalmers, London, 1811, pp. 70–78; “Emerson’s Works,”
London, 1873, Vol. II. p. 35; “The Library” for April 1902, has,
at pp. 131–132, the arms of the Digbys.

=A.D. 1644.=--Descartes (René), a prominent French philosopher and mathematician, publishes his “Principia Philosophiæ,” divided into four parts; the first giving an exposition of the principles of all human knowledge, the second treating of the principles of natural things, and the third and fourth parts developing his theory of vortices. His main idea was that a rush of subtle matter passes very rapidly through the earth from the equator towards each pole, being opposed by magnetic substances throughout its passage and that the sun is the centre of a vortex of an ethereal fluid, whose whirling motion produces the revolution of planets about the sun, or around the fixed stars. Moreover, as Noad states it, “the vortex moves with the greatest facility in a particular direction, one of its ends being always turned toward the north.”

One of the most prominent fellow-students of Descartes was Marin Mersenne, who joined the religious Order of “Minimes,” and who, after publishing in 1634 and 1639 “Les Mécaniques de Galilée” and “Nouvelles Découvertes de Galilée,” brought out, during the years 1644 and 1647, his well-known “Cogitata physico-mathematica,” which, Montucla says, contains _un océan d’observations de toutes espèces_ ... and embraces a very interesting treatise on navigation besides many letters from leading scientists of that period not elsewhere to be found.

REFERENCES.--“La grande Encyclopédie,” Vol. XXIII. pp. 730–731;
Larousse, “Dict.,” Vol. XI. p. 94; “Biographie Générale,” Vol.
XXXV. pp. 118–123; “The English Cyclopædia,” Vol. IV. p. 206;
Alex. Chalmers, “Gen. Biog. Dict.,” London, 1811, Vol. XXII.
pp. 81–83; “Biographie Universelle,” Vol. X. pp. 465–473;
Whewell, “Hist. of the Ind. Sc.,” Vol. I. pp. 323, 328, 338,
339, 343, 354, 387, 423, 429, 430; Vol. II. p. 220; likewise
pp. 320 and 390 of Vol. I. relative to Le Père Marin Mersenne
and pp. 391 and 423 concerning the “Traité de Physique” of
James Rohault; Playfair’s Fourth Dissertation in the eighth
edition of the “Encycl. Britann.”; “Essai théorique ... des
connaissances humaines,” par G. Tiberghien, Bruxelles, 1844,
Vol. I. pp. 472–495; Dr. W. Windelband, “History of Philosophy,”
New York, 1893, pp. 380–381, 391–396; Dr. F. Ueberweg, “History
of Philosophy,” New York, 1885, Vol. II. pp. 41–55; Alfred
Weber, “History of Philosophy,” translated by Frank Thilly, New
York, 1896, pp. 305–323; Ruard Andala, “Descartes in reality
the overturner of Spinosism and the architect of experimental
Philosophy”; Erasmus Bartholinus, “De Cometis,” Copenhagen,
1664–1665 (“Biog. Univ.”; Weidler, p. 508) Mahaffy, 1880;
Houzeau et Lancaster, “Bibl. Gen.,” Vol. II. for Descartes, p.
119, and for Mersenne, p. 204; “Journal des Savants” for Feb.
1826, p. 103, for Feb. 1827, p. 110, also for Aug.-Oct. 1850,
Dec. 1860, Jan.-Feb. 1861, Oct.-Nov. 1869, Feb., April and July
1870, Mar.-April 1880, Aug. 1884, April 1898, Feb. 1899.

=A.D. 1646.=--Browne (Sir Thomas), an eminent English physician and writer, publishes the well-known treatise “Pseudodoxia Epidemica, or Inquiries into Vulgar and Common Errors,” which ran through six editions in twenty-seven years, and upon which his fame is principally established.

With regard to the possibility of such a magnetic telegraph as Strada speaks of he says (Book II. chap. iii.): “The conceit is excellent and, if the effect would follow, somewhat divine; whereby we might communicate like spirits, and confer on earth with Menippus in the moon. And this is pretended from the sympathy of two needles, touched with the same loadstone, and placed in the centre of two abecedary circles or rings, with letters described round about them, one friend keeping one and another keeping the other, and agreeing upon the hour when they will communicate, at what distance of place soever, when one needle shall be removed unto another letter, the other, by wonderful sympathy, will move unto the same.”

As the result of experiment, he found that “though the needles were separated but half a span, when one was moved the other would stand like the pillars of Hercules, and if the earth stand still, have surely no motion at all.... By electrical bodies,” he says, “I understand not such as are metallical, mentioned by Pliny and the ancients; for their _electrum_ was a mixture made of gold, with the addition of a fifth part of silver; a substance now as unknown as true _aurichalcum_, or _Corinthian_ brass, and set down among things lost by Pancirollus. Nor by electric bodies do I imagine such only as take up shavings, straws and light bodies, amongst which the ancients placed only _jet_ and _amber_, but such as, conveniently placed unto their objects, attract all bodies palpable whatsoever. I say conveniently placed, that is, in regard of the object, that it be not too ponderous or any way affixed; in regard of the agent, that it be not foul or sullied, but wiped, rubbed and excitated; in regard of both, that they be conveniently distant, and no impediment interposed. I say, all bodies palpable, thereby excluding fire, which indeed it will not attract, nor yet draw through it, for fire consumes its effluxions by which it should attract.”

The different chapters of this second book treat of the loadstone, of bodies magnetical and electrical, of magnetical rocks and attractive mountains, and also make allusion to the cross on the church of St. John in Ariminium, to the reported magnetical suspension of Mahomet’s tomb, etc. etc.

At pp. 64, 81 and 87 of Chap. II he says: “Neither is it onely true, what Gilbertus first observed, that irons refrigerated North and South acquire a directive faculty; but if they be cooled upright and perpendicularly, they will also obtain the same.... Now this kind of practice, Libavius, Gilbertus and lately Swickardus, condemn, as vain and altogether unuseful; because a loadstone in powder hath no attractive power; for, in that form, it omits the polarity and loseth those parts which are the rule of attraction.... Glasse attracts but weakely though cleere, some slick stones and thick glasses attract indifferently; Arsenic not at all; Saltes generally but weakely, as Sal Gemma, Allum and also Talke, nor very discoverably by any frication; but, if gently warmed at the fire and wiped with a dry cloth, they will better develop their Electricities.”

At Chapter XVII of the seventh book of the above-mentioned treatise, Browne makes allusion to “the story of Frier Bacon that made a Brazen Head to speak these words: “_Time is_....”

REFERENCES.--“Library of Literary Criticism,” Chas. Wells
Moulton, Vol. II. p. 339–345; “Fortnightly Review,” for Oct.
1905, pp. 616–626, “Sir Thomas Browne and his Family”; Edmund
Gosse, in the “English Men of Letters Series”; Browne’s “Letter”
inserted in the “Biographia Britannica,” also his entire works,
recognized as an encyclopædia of contemporary knowledge, and
which were published in four octavo volumes by Simon Wilkins,
F.S.A., London, 1836.

=A.D. 1653.=--In the third edition of “The Jewell House of Arte and Nature,” by Sir Hugh Plat, originally published in 1594, and wrongly attributed in Weston’s “Catalogue” to Gabriel Plattes, is to be found the following allusion to the loadstone: “And though the adamant be the hardest of all stones, yet is it softened with Goa’s blood and there is a special antipathy between that and the loadstone, which is of the colour of rusty iron, and hath an admirable vertue not onely to draw iron to it self, but also to make any iron upon which it is rubbed to draw iron also, it is written notwithstanding that being rubbed with the juyce of Garlick, it loseth that vertue and cannot then draw iron, as likewise if a Diamond be layed close unto it.”

This “special antipathy” of garlick, and of the diamond--whether or not the latter be softened with Goa’s (goat’s) blood--is treated of very fully by many other authors, notably:

Pliny, “Nat. Hist.,” Holland tr. 1601, Chap. IV. p. 610;
Plutarch, “Quæstones Platonicæ,” lib. vii. cap. 7; Claudius
Ptolemæus, “Opus Quadripartitum,” lib. i. cap. 3; St. Augustine,
“De Civitate Dei,” lib. xxi.; Bartholom. de Glanvilla, “Liber de
Proprietatibus Rerum,” lib. xvi.; Pietro di Abano, “Conciliator
Differentiarum,” 1520, pp. 72–73, or the Venice edition of 1526,
cap. 51; Joannes Ruellius, “De Natura Stirpium,” 1536, pp. 125,
530; Ibn Roschd’s “Comment on Aristotle,” 1550, T. IV. p. 143t;
Cardinal de Cusa, “Opera,” 1565, p. 175; C. Julius Solinus,
“De Memorabilibus,” cap. 64; Walter Charleton, “A Ternary of
Paradoxes,” London, 1650, pp. 40–41; Thomas Browne, “Pseudodoxia
Epidemica,” 1658, p. 74; G. B. Porta, “Naturall Magick,” 1658,
Chap. XLVIII and Chap. LIII--from both of which chapters
extracts appear at the A.D. 1558 entry; “Journal des Savants”
for January 1894; Chas. de Rémusat, “Hist. de la Philos.,”
Paris, 1878, Vol. II. p. 187.

Rohault--at p. 186 of his 1728 “Syst. of Nat. Phil.”--says: “As to what some writers have related, that a loadstone will not attract iron if there be a diamond near and that onions and garlic will make it lose its vertue; these are contradicted by a thousand experiments which I have tried. For I have shown that this stone will attract iron through the very thickest diamonds and through a great many thick skins which an onion is made up of.”

REFERENCES.--“Dict. of Nat. Biography,” Vol. XLV. pp. 407–409,
giving many particulars; J. B. J. Delambre, at A.D. 1635. For
Gabriel Plattes, see the same “Dict. of Nat. Biography,” Vol.
XLV. p. 410.

=A.D. 1657.=--Schott (Gaspar)--P. Gaspar Schott--a German Jesuit who was sent to teach natural philosophy and mathematics at Palermo, Sicily, is the author of several very curious works on physics, of which the most important alone will here be noted.

“Magiæ Universalis Naturæ et Artis,” etc., appeared at Herbipoli in 1657, 1658, 1659. In the first book of the fourth volume (or part) he indicates, according to Kircher, whom he had met while in Rome, the means of conveying one’s thoughts at a distance by the loadstone, and he alludes to the speaking head constructed by Albertus Magnus, while, in the third and fourth books of the same volume, he gives a long treatise on the loadstone as well as an account of numerous experiments made with it.

“De Arte Mechanica,” etc. (“Mechanicæ,” etc.), Herbipoli, 1657–1658, contains, in Part II. class i. p. 314, the first published notice of Von Guericke’s experiments.

“Physica Curiosa sive Mirabilia Naturæ,” etc., Herbipoli, 1662 (which may justly be considered a continuation of the “Magiæ Universalis”), treats in the eleventh book of St. Elmo’s fire, thunder and meteors in general.

“Technica Curiosa sive Mirabilia Naturæ,” etc., Herbipoli, 1664, alludes, in the first two books, to the experiments made by Von Guericke and by Boyle, and gives the contents of eight letters written him by the first named.

“Schola Steganographica,” etc., Norimbergæ, 1665, gives, at pp. 258–264, a description of the dial telegraph of Daniell Schwenter.

“Jocoseriorum Naturæ et Artis,” etc., published about 1666, alludes to the “Thaumaturgus Mathematicus” of Gaspar Ens, published at Cologne, 1651, as well as to the “Deliciæ Physico-Mathematicæ” of Daniell Schwenter and Geo. Philippi Harsdoerffer (Senator of Nuremberg), to “La Récréation Mathématique” of Jean Leurechon, and to the works of Cardan, Mizauld, Aldrovandi and others.

REFERENCES.--“Notice Raisonnée des Ouvrages de Gaspar Schott,”
par M. L’Abbé Mxxx de St. Léger de Soissons, Paris, 1785, pp. 6,
31, 32, 37, 44, 70; Muirhead’s translation of Arago’s Eloge de
James Watt, London, 1839, p. 51.[46]

=A.D. 1660.=--Guericke (Otto von), a burgomaster of Magdeburg, Prussian Saxony, constructs the first frictional electric machine. It consisted of a globe of sulphur, cast in a glass sphere, and mounted upon a revolving axis, which when rubbed by a cloth pressed against it by the hand, emitted both sound and light. It was Guericke who “heard the first sound and saw the first light in artificially excited electricity.” He proved that light bodies, when attracted by an excited electric, were immediately repelled by the latter and became incapable of a second attraction until touched by some other body; also that light bodies develop electrical excitation when suspended within the sphere of an excited electric.

REFERENCES.--“Experimenta Nova Magdeburgica,” 1672, lib.
iv, cap. 15, p. 147, also all relating to the sulphur globe
reproduced from the “Experimenta Nova” at end of Figuier’s
“Exposition et Histoire,” etc., Vol. IV. Paris, 1857; Moncony,
Voyages, 1665; Schott (Gaspar), “Technica Curiosa,” etc.,
Norimbergæ, 1664; “Abhandlungen zur Geschichte der Mathem.,”
Leipzig, 1898, Vol. VIII. pp. 69–112, for the two articles
by Ferdinand Rosenberger on the development of the electric
machine, etc., from the time of Von Guericke.

=A.D. 1660.=--At the meeting of the English Royal Society, held June 5, 1660, Magnetical Remedies were discoursed of. Sir Gilbert Talbot promised to bring in what he knew of _sympatheticall cures_, and those who possessed any _powder of sympathy_ were requested to fetch some at the next meeting.

=A.D. 1661.=--Somerset (Edward), second Marquis of Worcester, an English inventor, announces, in his “Century of Inventions” that he has discovered “a method by which at a window as far as the eye can discover black from white, a man may hold discourse with his correspondent, without noise made or notice taken; being, according to occasion given, or means afforded, _ex re nata_, and no need of provision beforehand: though much better if foreseen, and course taken by mutual consent of parties.” This method, he asserts, he can put into practice “by night as well as by day, though as dark as pitch is black.”

REFERENCES.--Dircks’ “Life of Worcester,” p. 357; “Dictionary of
National Biography,” Vol. LIII. pp. 232–237.

=A.D. 1662.=--Rupert (Prince Robert), of Bavaria, son of Frederick V, elector palatine, and one of the founders of the Royal Society of London, is credited with the discovery of the curious glass bubbles called “Rupert’s drops.” These are merely drops of glass thrown, when melted, into water, and thus becoming suddenly consolidated into a shape somewhat resembling the form of a tear. The globular end may be subjected to quite a smart stroke without breaking, but if a particle of the tail is nipped off, the whole flies into fine powder with almost explosive violence.

“Mr. Peter did show us the experiment (which I had heard talked of) of the chymicall glasses, which break all to dust by breaking off a little small end; which is a great mystery to me” (Samuel Pepys, “Diary,” January 13, 1662).

Sir David Brewster discovered that the fracture of these unannealed drops was accompanied by the evolution of electrical light, which appears even when they are broken under water. Mr. Bennet observed that when one of the drops was placed upon a book, the latter was electrified negatively.

REFERENCES.--The articles on “Annealing,” “Optics,” and
“Electricity” in the “Encyclopædia Britannica”; also the
biography in “Penny Cycl.,” Vol. XX. pp. 226–227; Le Cat,
“Memoir,” London, 1749–1750, or _Philos. Trans._, XLVI. p. 175.

=A.D. 1665.=--Grimaldi (Francesco Maria), Italian philosopher (1618–1663), member of the Order of Jesuits and an associate of the astronomer Giovanni Battista Riccioli (at A.D. 1270) is the author of the important work “Physico mathesis de Lumine ...” which cites the discovery of magnetism produced by the perpendicular holding of an iron bar.

REFERENCES.--_Phil. Trans._ for 1665; “Engl. Cycl.,” article
“Biography,” Vol. CXI. p. 207; Larousse, “Dict.,” Vol. VIII,
p. 1531. And, for Riccioli’s works, see Houzeau et Lancaster,
“Bibliog. Gén.,” Vol. III. p. 238; “Journ. des Sçavans” pour
1665 et 1666, pp. 642–647.

=A.D. 1665.=--Glanvill (Joseph), an eminent English divine and philosopher, Chaplain to King Charles II and F.R.S., sometimes called “Sadducismus Triumphatus Glanvill,” endorses in his “Scepsis Scientifica” (“the vanity of dogmatizing recast”)--published originally in 1661--the views advanced previously by the Jesuit Leurechon, and, after discussing the objections of Sir Thomas Browne, expresses the belief that “to confer at the distance of the Indies by sympathetic conveyances may be as usual to future times as to us in literary correspondence.”

A writer in the “Bath Chronicle” reproduced a long extract from Glanvill’s work, the concluding sentence of which, he says, seems to have anticipated the electric telegraph. It is as follows: “But yet to advance another instance. That men should confer at very distant removes by an extemporary intercourse is a reputed impossibility; but yet there are some hints in natural operations that give us probability that ’tis feasible, and may be compassed without unwarrantable assistance from demoniack correspondence. That a couple of needles equally touched by the same magnet, being set in two dials exactly proportioned to each other, and circumscribed by the letters of the alphabet, may effect this ‘magnale’ (_i. e._ important result) hath considerable authorities to avouch it.

“The manner of it is thus represented: Let the friends that would communicate take each a dial, and, having appointed a time for their sympathetic conference, let one move his impregnate needle to any letter in the alphabet, and its affected fellow will precisely respect the same. So that, would I know what my friend would acquaint me with, ’tis but observing the letters that are pointed at by my needle, and in their order transcribing them from their sympathized index, as its motion directs; and I may be assured that my friend described the same with his, and that the words on my paper are of his inditing. Now, though there will be some ill-contrivance in a circumstance of this invention, in that the thus impregnate needles will not move to, but avert from each other (as ingenious Dr. Browne hath observed), yet this cannot prejudice the main design of this way of secret conveyance; since it is but reading counter to the magnetic informer, and noting the letter which is most distant in the Abecederian circle from that which the needle turns to, and the case is not altered.

“Now, though this desirable effect may possibly not yet answer the expectations of inquisitive experiment, yet ’tis no despicable item, that by some other such way of magnetick efficiency it may hereafter with success be attempted, when magical history shall be enlarged by riper inspections; and ’tis not unlikely but that present discoveries might be improved to the performance.”

Glanvill is also the author of “Philosophical Considerations Touching Witches and Witchcraft,” 1666, and of “The Sadducismus Triumphatus,” 1681.

REFERENCES.--“Dict. of Nat. Biog.,” 1908, Vol. VII. pp. 1287–8;
Larousse, “Dict.,” Vol. VIII. pp. 1294–1295; “Nature,” Vol. XVI.
p. 269; “Histoire de la Philosophie,” par Charles de Rémusat,
Paris, 1878, Vol. II. chap. xi. pp. 184–201; “The General
Biog. Dict.,” Alex. Chalmers, London, 1811, Vol. XVI. pp.
12–17; “Joseph Glanvill,” by Ferris Greenslet, New York, 1905;
“Imperial Dict. of Universal Biography,” Vol. II. p. 642.

=A.D. 1666.=--Denys (William), hydrographer, of Dieppe, observes that the compasses placed in different parts of a vessel give different indications (Becquerel, “Magnétisme,” p. 119; “Journal des Sçavans” pour 1665 et 1666, p. 538).

=A.D. 1671.=--Richer (T.), French philosopher, who was sent by the Paris Academy of Sciences to the island of Cayenne for the purpose of determining the amount of terrestrial refraction and for other astronomical objects, is the first to make known the electrical powers of the _gymnotus electricus_.

REFERENCES.--Leithead, “Electricity,” Chap. XII; Fahie, “El.
Tel.,” p. 171; Bertholon, “Elec. du Corps Humain,” 1786, Vol. I.
p. 171; _Mém. de l’Acad. des Sciences_, 1677, Art. VI; Richer,
“Observations,” etc., Paris, 1679; Bancroft, at A.D. 1769;
“Cosmos,” 1859, Vol. V. pp. 23–24.

=A.D. 1671.=--Rohault (Jacques), a French philosophical writer, and one of the earliest, ablest and most active propagators of the Cartesian philosophy in France, publishes at Paris the first edition of his “Traité de Physique,” at Part III. chap. viii. pp. 198–236 of which he treats especially of amber and of the loadstone. The same passages can be seen at Vol. II. part iii. chap. viii. pp. 163, etc., of Rohault’s “System of Natural Philosophy,” published in London during the year 1723, and at the same chapter, pp. 388, etc., of “Jacobi Rohaulti Physica,” Londini, 1718.

The latter is the last and best edition of the well-known classical translation, originally made in 1697, by Dr. Samuel Clarke, who was the friend of Sir Isaac Newton and chaplain to Bishop Moore, of Norwich. Through this work Clarke introduced very many critical notes exposing the fallacies of the Cartesian system. The “Physica” passed through four editions as the Cambridge University textbook before it was made to give way to the treatises of Newton.

=A.D. 1672.=--Sturm (John Christopher), a very able German mathematician, who was for thirty-four years professor of natural philosophy at the University of Altdorf (Franconia), and who, after vainly attempting to satisfactorily unite the Aristotelian and Cartesian doctrines finally adopted the Baconian philosophy, establishes the “Collegium Curiosum” on the plan of the celebrated Italian “Accademia del Cimento,” alluded to under the A.D. 1609 date.

The society was founded for the purpose of studying, repeating and even modifying the most notable philosophical experiments of the day, such as those made by Von Guericke, Boyle, Hooke and others, and its proceedings were published in 1676 and 1685 under the title of “Collegium Experimental sive Curiosum, etc.”

=A.D. 1673.=--Hevelius--Hevel--Hovel--Hövelke (Joannes), an eminent Polish astronomer, member of the English Royal Society, and a great friend more particularly of le Père M. Mersenne, of Gassendi and of Kircher, publishes during 1673 the first part of his great work “Machina Cœlestis”--dedicated to Louis XIV--the entire second part of which, issued in 1679, was destroyed by fire with the exception of seven copies. This explains its extreme scarcity. It was this work which led to the public controversy between Hevelius and Dr. Hooke who published, in London, during 1674 his “Animad. in Mach. Celest. Hevelii.”

It is said that, next to John Flamsteed, Hevelius was the most accurate observer of the heavens in his day (“The Reliquary,” London, Vol. XIV. pp. 149–159 and Vol. XV. pp. 34–38; “Journal des Savants” for March, June and November 1836). He had already published “De Variatione acus magneticæ” (_Opusc. Act. Erudit. Lips._, Vol. I. p. 103), also a report of the variations of the magnetical needle during 1670, which can be found in the _Phil. Trans._, Vol. V. for 1670, p. 2059, or in Hutton’s abridgments, London, 1809, Vol. I. p. 514.

REFERENCES.--Larousse, “Dict.,” Vol. IX. pp. 266–267; “Biog.
Gén.,” Vol. XXV. pp. 285–294; Delambre, “Hist. de l’Astron.
Mod.,” Vol. II. pp. 434–484; Weidler, “Hist. Astron.,” p. 485;
“Mem. Roy. Soc.,” 1739, Vol. I. p. 274.

=A.D. 1675.=--Boyle (Robert), Irish natural philosopher and chemist, seventh son of Richard Boyle, Earl of Cork, and one of the first members of what he calls the “Invisible” or “Philosophical” College, which has since become the Royal Society,[47] gives, in his “Philosophical Works,” the result of his many experiments upon magnetism and electricity.

John Evelyn in his letter to Mr. Wotton, March 30, 1695 (“Memoirs, Diary and Correspondence,” by Wm. Bray, London, p. 716), says of Boyle: “It must be confess’d that he had a marvailous sagacity in finding out many usefull and noble experiments. Never did stubborn matter come under his inquisition but he extorted a confession of all that lay in her most intimate recesses; and what he discover’d he as faithfully register’d, and frankly communicated....”

Prof. Tyndall remarks (“Lecture,” February 4, 1875): “The tendency to physical theory showed itself in Boyle. He imagined that the electrified body threw out a glutinous or unctuous effluvium, which laid hold of small bodies, and, in its return to the source from which it emanated, carried them along with it.”

A few of his many characteristic remarks and observations are, however, best given in his own words, as extracted from the “Philosophical Works” above alluded to:

“The invention of the mariner’s needle, which giveth the direction, is no less benefit for navigation than the invention of the sails, which give the motion” (London, 1738, Vol. I. p. 62).

“I, with a certain body (rough diamond), not bigger than a pea, but very vigorously attractive, moved a steel needle, freely poised, about three minutes after I had left off rubbing it” (Vol. I. p. 508). Speaking elsewhere of his experiments with diamonds, he says: “But when I came to apply it (the loadstone) to one more, which look’d somewhat duller than almost any of the rest, I found that it had in it particles enough of an iron nature to make it a magnetical body and observed without surprise that not only it would suffer itself to be taken up by the strongest pole of the loadstone, but when the pole was offer’d within a convenient distance it would readily leap through the air to fasten itself to it.”

“I removed a piece of amber in the sunbeams till they had made it moderately hot and then found it would attract those light bodies it would not stir before” (Vol. I. p. 400, and Vol. III. p. 52).