Chapter XVII: Book I: chap. i. Therein, he says that Baptista Porta, who has made the (2)

“Whether from such experiments one may argue that it is but, as it were, by accident that amber attracts another body, and not this the amber; and whether these ought to make us question, if _electrics may_, with so much propriety, as has been generally supposed, _be said to attract_, are doubts, that my design does not oblige me to examine” (Vol. IV. p. 350).

REFERENCES.--John Evelyn’s “Diary,” Letter to Mr. Wotton, March
30, 1696; Libes’ “Histoire Phil. du Progrès de la Physique,”
Paris, 1810; Boyle’s “Mechanical Origine or Production of
Electricity,” 1675; Birch, “Life of Hon. R. Boyle,” 1743–1744;
Secondat’s “Histoire d’Electricité” (Observations physiques),
1750, p. 141; Whewell, “Hist. of Ind. Sciences,” 1859, Vol. I.
pp. 395, 396. Priestley’s “History of Electricity,” 1775, pp.
5–8; M. Reael, “Observ. a. d. Magnectsteen,” 1651, alluded to
at note, p. 486, Vol. I. of Van Swinden’s 1784 “Recueil,” etc.;
Van Swinden, Vol. II. pp. 353, 359–361; “Biblioth. Britan.”
(Authors), Robt. Watt, Edinburgh, 1824, Vol. I. pp. 142–3;
Aikin’s “G. Biography,” and Martin’s “Biog. Philosophica,”
in “General Biog. Dict.,” by John Gorton, London, 1833, Vol.
I; _Phil. Trans._, Vol. VIII for 1673, p. 6101 and Hutton’s
abridg., Vol. II. p. 90; Boyle, London, 1673, “Essays of the
... Effluviums” (Subtility), pp. 38–42, 52–53; (Efficacy) pp.
18, 19, 32, 33; (Determinate Nature) pp. 21, 57; “An Essay ...
of Gems,” London, 1672, pp. 108–129; Ch. W. Moulton, “Library
of Literary Criticism,” Vol. II. pp. 416–420; “Critical Dict.
of Engl. Lit.,” S. Austin Allibone, Philad., 1888, Vol. I.
pp. 232–233; “Essays in Historical Chemistry,” T. E. Thorpe,
London, 1894, pp. 1–27; Eighth “Britannica,” V. p. 259 for notes
of Boerhaave, also the “Britannica” 1st Dissertation, p. 47,
and 4th Dissertation p. 597; “History and Heroes of the Art of
Medicine,” J. Rutherfurd Russell, London, 1861, pp. 233–246.

Consult also Boyle’s “New Exper. Physico-Mechanical,” etc.,
in which the 16th Exp. is “concerning the operation of the
loadstone”; Boyle’s “A Continuation of New Exp.,” etc., in which
the 31st Exp. is “about the attractive virtue of the loadstone
in an exhausted receiver,” and in which are “Notes, etc.,
about the atmospheres of consistent bodies,” etc., as well as
“Observations about the exciting of the electricity of bodies,”
and concerning the electrical emanations and effluviums. Boyle’s
“Tracts Containing Some Suspicions Concerning some Occult
Qualities of the Air; with an Appendix Touching Celestial
Magnets,” etc. His “Phil. Works,” London, 1744, Vol. III. pp.
65, 67 and 70, 647, etc., give “Experiments and Notes about the
Mechanical Origin or Production of Electricity.”

For full accounts of the Royal Society, alluded to above, see
the histories written by Thomas Sprat (1667), by Thomas Birch
(1756), by Thomas Thomson (1812), and by Chas. Richard Weld
(1847–1848).

=A.D. 1675.=--Picard (Jean), eminent astronomer, who succeeded Gassendi (A.D. 1632) as professor of astronomy at the Collège de France, is the first to observe electric light _in vacuo_. According to Tyndall (“Lessons in Electricity,” p. 88) it was while carrying a barometer from the Observatory to the Porte Saint-Michel in Paris that he noticed light in the vacuous portion. Sebastien and Cassini observed it afterwards in other barometers (see Tyndall’s “Lecture V.” p. 91, for Priestley’s description of the electric light _in vacuo_).

It was this same scientist who had already given, in his “Mesure de la Terre,” 1671, Article IV, the description of the measurement of a degree of latitude made with instruments of his own manufacture.

REFERENCES.--Humboldt, “Cosmos,” 1859, Vol. V. pp. 23, 24;
Larousse, “Dict.,” Vol. XII. p. 937; “Phil. Hist. and Mem. of
the Roy. Acad. at Paris,” London, 1742, Vol. I. pp. 208–221.

=A.D. 1675.=--Newton (Sir Isaac), prominent English mathematician and natural philosopher, of whom Macaulay says that “in no other mind have the demonstrative faculty and the inductive faculty coexisted in such supreme excellence and perfect harmony,” communicates to the Royal Society his discovery that excited glass will attract any light bodies even to the surface opposite to that upon which it has been rubbed. This was successfully demonstrated by the Society, January 31, 1676.

He improved the electric machine by substituting a glass globe for the globe of sulphur made use of by both Von Guericke and Boyle, the rubbers in every case being the hands of the operator.

He appears to have somewhat anticipated Franklin’s great discovery, judging by the following letter he addressed, December 15, 1716, to the Rev. Dr. Law, in Suffolk:

“Dear Doctor,” it begins, “He that in ye mine of knowledge
deepest diggeth, hath, like every other miner ye least breathing
time, and must sometimes at least come to terr; alt (terra
alta) for air. In one of these respiratory intervals I now sit
doune to write to you, my friend. You ask me how, with so much
study, I manage to retene my health. Ah, my dear doctor, you
have a better opinion of your lazy friend than he hath himself.
Morpheus is my best companion; without eight or nine hours
of him ye correspondent is not worth one Scavenger’s peruke.
My practizes did at ye first hurt my stomach, but now I eat
heartily enow, as y’ will see when I come down beside you. I
have been much amused by ye singular φενομενα resulting from
bringing a needle into contact with a piece of amber or resin
fricated on silke clothe. Ye flame putteth me in mind of sheet
lightning on a small--how very small--scale. But I shall in my
epistles abjure philosophy, whereof when I come down to Sakly
I’ll give you enow. I begin to scrawl at five mins. from nine of
ye clk, and have in writing consumed ten mins. My Lord Somerset
is announced.”

Æther, according to Sir Isaac Newton, is a thin subtile matter much finer and rarer than air. Sometimes, it is termed by him, a subtil spirit, as in the latter part of his “Principia,” and sometimes a subtil ætherial medium, as in his “Optics.” By many it is supposed to pervade all space, also the interior of solid bodies, and to be the medium of the transmission of light and heat. The æther of Descartes was his _materia subtilis_ or his First Element: by which he understood a “most subtil matter very swiftly agitated, fluid, and keeps to no certain figure, but which suits itself to the figure of those bodies that are about it. His Second Element consists of small Globules; that is, bodies exactly round and very solid, which do not only, like the First Element, fill up the pores of bodies but also constitute the purest substance of the Æther and Heaven” (Blome’s translation of Descartes’ “Philosophy,” p. 101; R. Lovett, “The Subtil Medium Prov’d”; _Phil. Mag._, Vol. XVIII. p. 155).

During the years 1686 and 1687 Newton composed his “Principia,” a work which Lagrange pronounced “la plus haute production de l’esprit humain”: “the greatest work on science ever produced” (Sir Robt. Ball), and “which will be memorable not only in the annals of one science or of one country, but which will form an epoch in the history of the world.” This was published at Halley’s expense. As Brewster says (1686, Chap. XII): “It is to Halley alone that science owes this debt of gratitude. It was he who tracked Newton to his college, who drew from him his great discoveries, and who generously gave them to the world.”

In the twenty-third proposition of the second book, fifth section, Newton says: “The virtue of the magnet is contracted by the interposition of an iron plate and is almost terminated at it, for bodies further off are not so much attracted by the magnet as by the iron plate.” And in Book III. prop. vi. he thus expresses himself: “The magnetic attraction is not as the matter attracted; some bodies are attracted more by the magnet, others less; most bodies not at all. The power of magnetism in one and the same body may be increased and diminished, and is sometimes far stronger for the quantity of matter than the power of gravity; and in receding from the magnet decreases, not in the duplicate, but almost in the triplicate proportion of the distance, as nearly as I could judge from some rude observations.”

Newton is said to have carried in his ring a magnet weighing but three grains, which could raise 746 grains, or nearly 250 times its own weight. This magnet naturally excited much admiration, but is greatly surpassed in power by that formerly belonging to Sir John Leslie, and now in the Physical Collection at Edinburgh, weighing three and one-half grains, and having a carrying power of 1560 grains.

REFERENCES.--Brewster’s “Life of Sir I. Newton,” pp. 307, 308;
“Dict. of Nat. Biog.,” Vol. XL. pp. 370–393; Ch. W. Moulton,
“Library of Literary Criticism,” Vol. II. pp. 710–726; “Bibl.
Britan.” (Authors), Robt. Watt, Edinburgh, 1824, Vol. II., p.
701; Harris, “Magnetism,” Vol. III. p. 11; Ninth “Britannica,”
Vol. XV. p. 274; Whewell, “Hist. of the Ind. Sciences,” 1858,
Vol. I. pp. 385–488; the interesting note at foot of p. 683
of the Fourth Dissertation in the “Encyclopædia Britannica”;
“Muspratt’s Chemistry,” Vol. II. p. 255; the English “Chemical
News” for November 1867, and January 1868, reproducing Sir David
Brewster’s letters to the London “Athenæum” and London “Times,”
likewise Dr. Crompton’s paper read before the Manchester
Literary and Philosophical Society in October 1866; _Phil.
Trans._, Vol. LXIV. Part I for 1774, p. 153: “Remarks of John
Winthrop upon ... Castillione’s Life of Sir Isaac Newton”; Dr.
Geo. Miller, “Hist. Phil. Ill.,” London, 1849, Vol. III. pp.
414–415; “Newton, sa vie et ses œuvres” in “Cosmos,” September
27, 1890 to December 13, 1890; “Journal des Savants” for April,
May and June 1832; for April 1846, March, April, May, June, July
and August 1852, October, November 1855; Houzeau et Lancaster,
“Bibl. Gén.,” Vol. II, 1882, pp. 213–214, 1586; “Hist. de la
Philosophie,” par Chas. de Rémusat, Paris, 1878, Vol. II. chap.
xii. pp. 202–222.

=A.D. 1676.=--Haward, master of several sailing vessels, and a man of good credit (_Phil. Trans._, Vol. XI. No. 127, p. 647, of July 18, 1676), states that “being on board of the ship Albemarle, July 24, 1641 ... in latitude of Bermuda ... after a terrible clap of thunder ... it was found that the compass card was turned around, the N. and S. points having changed positions and, though Mr. Grofton brought with his finger the flower-de-lys to point directly N., it would immediately, as soon as at liberty, return to this new unusual posture, and upon examination he found every compass (three) in the ship of the same humour; which ... he could impute to nothing else but the operation of the lightning or thunder mentioned.” The above is also alluded to at p. 33 of Vol. III. of Boyle’s “Phil. Works,” London, 1738, with this addition: “One of the compasses, pointing West, was brought to New England, where, the glass being broke and the air gaining entrance, it lost its virtue. But one of the others is in that country possess’d by Mr. Encrease Mather, the North point of the needle remaining South to this day.”

=A.D. 1677.=--At p. 14 of an exceedingly curious publication entitled “A Rich Cabinet with a Variety of Inventions,” etc., written by J. W. (_i. e._ John White, of London), who calls himself “a lover of artificial conclusions,” will be found an article on “Divers rare, conceited motions performed by a magnet or loadstone.”

=A.D. 1678.=--Redi (Francesco), well-known Italian scientist, physician to the Grand Duke Ferdinand II, publishes his “Experimenta circa res diversas Naturales,” wherein he is first to communicate the fact that the shock of the _raia torpedo_ can be transmitted to the fisherman through the line and rod connecting him with the fish.

REFERENCES.--Leithead, “Electricity,” Chap. XII; the Firenze,
1671 ed. of Redi’s “Esperienze,” etc., pp. 47–54; _Phil. Trans._
for 1673, Vol. VIII. p. 6003; _Sci. Am. Supp._, No. 457, pp.
7300–7302; Matteucci, “Recherches,” 1837 and 1867; Eschinardi
(F. della Compagnia di Gesü), “Lettera al S. Francesco Redi,”
Roma, 1681, wherein are detailed many curious experiments,
including some treating of the magnetic needle by which agency
are foretold sudden attacks of earthquakes, etc. etc.

=A.D. 1679.=--Maxwell (William)--Guillelmo Maxvello--native of Scotland, author of “Medicina Magnetica,” offers to prove to various medical faculties that, with certain magnetic means at his disposal, he could cure any of the diseases abandoned by them as incurable (Blavatsky, “Isis,” Vol. I. p. 215).

REFERENCE.--J. H. Van Swinden, “Recueil de Mémoires,” etc., La
Haye, 1784, Vol. II. p. 367.

=A.D. 1683.=--Arrais (Edoardo Madeira), who had been physician to--João--John IV, the first Portuguese king of the house of Braganza, is the author of this much-delayed edition of a book entitled “Arbor Vitæ, or a physical account of the Tree of Life in the Garden of Eden.” It treats of occult qualities under the headings of “Doubts,” of which latter there are eight separate ones which constitute as many different chapters, from which the following extracts will prove interesting:

“Doubt” 5, p. 45. “Doth not the fish called _Torpedo_ render the
fishes that swim over it immovable, and stupefy the fisher’s arm
with its virtue diffused along his spear?”

“Doubt” 5, p. 46. “... as also there are divers sorts of fishes
that bring numness, as our _Torpedo_ doth.”

“Doubt” 5, p. 49. “And those that travail the coasts of Brasile
make mention of another fish, which causeth numness as our
_Torpedo_ doth: whence it becomes sufficiently manifest that
there are many kinds of _Torpedoes_ to be found. But this kind
lives especially in the river Itapecuro, in the country of the
Maragnani, and it is called _Perache_, or, as Gaspar Barlæus
observed, _Puraquam_, among those Barbarians. In shape and
greatness it resembles a kind of lamprey (or Muræna); they
use to kill it by striking it with staves; but the arm of him
that strikes and then his whole body is stupefied, and shakes
presently. Of which thing, Frier Christopher Severineus, Bishop
elect of Angola is my ocular witness....”

“Doubt” 7, p. 93. “For it is evident from experience that iron
is so indisposed by some qualities that it cannot be moved by
the magnet. That fishes swimming over the _Torpedo_, enclosed in
the mud or sand for the purpose, when they come to the places
whereto the virtue of the _Torpedo_ is extended can stir no
further; by which art she catches and eats them, as Aristotle
relates (6 ‘de Hist. Animal.,’ cap. 10; and 9 ‘de Hist.,’ cap.
37).”

“Doubt” 7, p. 94. “For if amber be dulled by moisture, its
virtue cannot produce motion in straws. If the virtue of the
_Torpedo_ reach the fishes swimming over her, or the
fisher’s arm their motive power cannot produce motion.”

“Doubt” 7, p. 96. “And for this cause, the virtue of the magnet
can produce motion in iron, not in other bodies, because it
finds in it Dispositions necessary on the part of the agent
which, being present, it can operate; not in other things. And,
for the same reason, amber moves straws, not iron nor stones.”

The preface to the “Arbor Vitæ ...” is written by Richard Browner M.L. Coll. Med., London, who translated out of Latin “The Cure of Old Age,” by Roger Bacon, wherein he gives quite a good account of the latter’s life and writings, and from which we extract but one passage likely here to be of some little interest, viz. at p. 155, regarding the component parts of a medicine: “By Amber here our author intends Amber Gryse (a bituminous body found floating on the sea): For he calls it Ambra and not Succinum (which is solid Amber). Besides, Succinum was never reckoned a spice as Amber is here. And though both Ambra and Succinum be great restorers of the animal spirits, yet the former is more efficacious.”

The “Biographie Générale,” Vol. III. p. 348, says that Duarte Madeyra Arraess, who died at Lisbon in 1652, was the author also of “Apologia,” 1638, of “Methodo,” 1642, and of “Novæ Philosophiæ,” 1650.

=A.D. 1683.=--Halley (Edmund), LL.D., who became English astronomer royal, makes known his theory of four magnetic poles and of the periodical movement of the magnetic line without declination. He states that the earth’s magnetism is caused by four poles of attraction, two of them being in each hemisphere near each pole of the earth. By the word _pole_ he means a point where the total magnetic force is a maximum, or, as he himself styles it, “a point of greatest attraction” (Walker, “Magnetism,” p. 317, etc.).

One of the magnetic poles he places near the meridian of Land’s End, not above 7 degrees from the North Pole, the other being about 15 degrees from the North Pole in the meridian of California, while the two south magnetic poles are placed respectively about 16 and about 20 degrees from the South Pole of the earth, and 95 degrees west, 120 degrees east of London.

In order to test Halley’s theory, the English Government permitted him to make three voyages in the Atlantic Ocean (1698, 1699, 1702), in vessels of which he had the command as post-captain. Humboldt states that these were the first expeditions equipped by any government for the establishment of a great scientific object--that of observing one of the elements of terrestrial force on which the safety of navigators is especially dependent.

The result of these voyages was the construction of the first accurate Magnetic Chart, whereon the points at which navigators have found an equal amount of variation were connected together by curved lines. This was the model of all charts of a similar nature since constructed. Halley remarked upon its completion: “The nice determination of the variation, and several other particulars in the magnetic system, is reserved for a remote posterity. All that we can hope to do is to leave behind us observations that may be confided in, and to propose hypotheses which after-ages may examine, amend or refute.”

See copy of his chart in Vol. I. No. I of “Terrestrial Magnetism,” also in Musschenbroek’s “Essais de Physique,” or, preferably, in Bouguer’s “Traité de Navigation,” where the lines for 1700 are in red ink, while those for 1744 are traced in black, thus readily indicating the changes in the declination.

REFERENCES.--Cavallo, “Magnetism,” and “Nat. or Exp. Phil.,”
Vol. II. p. 273; Lloyd, “Treatise on Magnetism,” 1874, p. 102;
_Sci. Am. Suppl._, No. 224, pp. 3570, 3571; Whewell, “Hist. of
the Inductive Sciences,” 1859, Vol. I. pp. 396–8, 435–7, 450,
451, 480, 481, and Vol. II. p. 225; Giambattista Scarella, “De
Magnete,” 1759, Vol. II; also G. Casali, “Sopra la Grandine,”
etc., 1767; “The Phil. Hist. and Mem. of the Roy. Ac. of
Sciences at Paris,” London, 1742, Vol. I. p. 245; Vol. II. pp.
240–244, 270, 349; “Magnetic Results of Halley’s Expedition
(1698–1700)” in “Terrestrial Magnetism,” September 1913, pp.
113–132; Houzeau et Lancaster, “Bibl. Gén.,” Vol. II. pp.
156–7; Dr. G. Hellmann “Neudrucke von schriften,” Nos. 4 and
8; Humboldt, “Cosmos,” 1859, Vol. V. pp. 59–60; John Wallis’s
letters to Halley, London (_Phil. Trans._ for 1702–1703), p.
106; _Phil. Trans._ for 1667, 1683, 1692; “Memoirs of the Roy.
Soc.,” 1739, Vol. II. p. 195; “A Bibliography of Dr. Edmund
Halley,” by Alex. J. Rudolph, in the “Bulletin of Bibliography”
for July 1905; “Old and New Astronomy,” by Richard A. Proctor,
1892, pp. 37–38; _Phil. Trans._ Vol. XIII for 1683, No. 148,
p. 208; Vol. XVII. p. 563; Vol. XXIII. p. 1106; Vol. XXIX. p.
165; Vol. XLII. p. 155; Vol. XLVIII. p. 239, also the following
abridgments: Hutton, Vol. II. p. 624; Vol. VI, pp. 99, 112; J.
Lowthorp, Vol. II. p. 285; Reid and Gray, Vol. VI. p. 177; Eames
and Martyn, Vol. VI. pp. 28, 286; Baddam, 1745, Vol. II. pp.
195–202; Vol. III. pp. 25–32.

AURORA BOREALIS, OR NORTHERN POLAR LIGHT

Dr. Halley was the first to give (_Phil. Trans._, No. 347) a distinct history of this phenomenon, which has certainly an electric as well as magnetic origin, and to which Gassendi originally gave the name it now bears, as has been stated at A.D. 1632.

According to Dr. Lardner (“Lectures,” Vol. I. p. 137), Prof. Eberhart, of Halle, and Paul Frisi, of Pisa, first proposed an explanation of the aurora founded upon the following: 1. Electricity transmitted through rarefied air exhibits a luminous appearance, precisely similar to that of the aurora borealis. 2. The strata of atmospheric air become rarefied as their altitude above the surface of the earth is increased, a theory which has since been countenanced by many scientists. It has been observed, notably by Dalton, of Manchester, that the primitive beams of the aurora are constantly in a direction parallel to that of the dipping needle, and that the latter appears most affected when the aurora is the brightest. Arago noticed that the changes of inclination amounted, upon one occasion to 7’ or 8’. The discovery that the magnetic needle was agitated during the presence of an aurora has been ascribed to Wargentin (_Am. Journal Sc._, Vol. XXX. p. 227), though it is claimed by the friends of Olav Hiörter (see A.D. 1740), that it was independently ascertained by the latter during the year 1741.

The well-known Swiss chemist Auguste Arthur De la Rive has made many important observations upon the electric character of the aurora, the experiments carried on by him in the mountains of Finland being thus described: “We surrounded the peak of a mountain with copper wire, pointed at intervals with tin nibs. We next charged the wire with electricity, and nearly every night during our stay produced a yellowish white light on the tin points, in which the spectroscope analysis revealed the greenish yellow rays so characteristic of the aurora borealis. On the peak of Pietarintumturi we were especially successful, an auroral ray making its appearance directly over and about 150 yards above the copper coil.”

A complete list of all auroras appearing prior to 1754 is to be found in Jean Jacques d’Ortons de Mairan’s, Paris, 1731, “Traité Physique de l’Aurore Boréale,” and a catalogue of auroræ observed, 1800–1877, has been made up by M. Zenger (_Sci. Am. Supp._, p. 10915). One of the most interesting displays is known as the _purple aurora_, alluded to in the Annals of Clan-mac-noise as having appeared A.D. 688 (Biot “Note sur la direction,” etc., _Comptes Rendus_, Tome XIX for 1844, p. 822). Between September 19, 1838, and April 8, 1839, Lottin, Bravais, Lilliehöök and Siljeström observed 160 auroras at Bossekop (69° 58’ N. lat.) in Finmark and at Jupvig (70° 6’ N. lat.); they were most frequent during the period the sun remained below the horizon, that is, from November 17 to January 25. During this night of 70 times 24 hours there were 64 auroras visible (_Comptes Rendus_, Tome X. p. 289; Martin, “Météorologie,” 1843, p. 453; Argelander, in the “Vorträgen geh. in der Königsberg Gesellschaft,” Bd. I. s. 259).

A Finnish physicist, named S. Lenström, who had been attached to the Nordenskjold Polar Expedition of 1868, visited Lapland in 1871, and, after a series of important observations, constructed an apparatus that permitted him to “artificially reproduce the light of the aurora.” The intensity of this light is so great at times that Lowenörn perceived the coruscations in bright sunshine on the 29th of January, 1786, and Parry saw the aurora throughout the day during the voyage of 1821–1823.

The height of the aurora has been variously estimated, but it is seldom found to be less than forty-five miles above the surface of the earth. Father Boscovich estimated at 825 miles the height of the one observed by the Marquis of Poleni on the 16th of December, 1737. The extent of the aurora, according to Dalton, has been known to cover an area of 7000 or 8000 square miles.

REFERENCES.--“Mem. de Turin,” An. 1784–5, Vol. I. part ii. pp.
328, 338; Young, “Lectures,” Vol. I. pp. 687, 716; Herschel,
“Prelim. Discourse,” pp. 93, 329, 330; _Phil. Trans._, 1753,
p. 350; Müller’s “Kosmischen Physik”; Noad, “Manual,” pp.
225–237; also all the references at pp. 187–196, Vol. I of
Humboldt’s “Cosmos,” Bohn, London, 1849, as well as in Ronalds’
“Catalogue,” pp. 23–24; Mairan, at Vol. X. p. 961, “Dict.
Univ.,” and Vol. XXVI. p. 161, of the “Biog. Universelle”;
_Trans. Cambridge Phil. Soc._, Vol. I; “Isis Unveiled,” Vol. I.
pp. 417, 418.

See likewise the “Pharsalia” of Marcus Annæus Lucanus,
translated by J. Krais, I. pp. 518–527; Plutarchus, “De facie in
orbe lunæ,” cap. 26; the “Annals” of Caius Cornelius Tacitus,
Germania, XLV. 1st ed., Venice, 1470; “Das Polarlicht,” H.
Fritz, Leipzig, 1881, pp. 4–6, 332; Mairan’s “Traité Physique,”
etc., 1731, pp. 179–181; Grégoire du Tour, _Lumière Electrique_,
1882, Vol. VII. p. 389; Elias Loomis, “The Aurora Borealis,”
etc., p. 220 of the Reports of Smiths. Inst., 1865; A. M. Mayer,
“Observations,” etc., _Amer. Jour. of Sc._, February 1871; “A
copy of the Catalogue of Aurorae Boreales observed in Norway
from the earliest times to June 1878” (“Nature,” December
4, 1902, p. 112); “La cause de l’aurore boréale,” Claudius
Arrhenius, in the _Revue Générale des Sciences_ for January 30,
1902, pp. 65–76; “Les Années Météores,” in “Le Cosmos,” Paris,
May 25, 1889, etc.; “Terrestrial Magnetism,” March 1898, p.
7 for Chronological Summary of Authors re Aurora; Rev. Jas.
Farquharson in “Abstracts of Sc. Papers Roy. Soc.,” Vol. II.
p. 391; Wm. Dobbie, _Phil. Mag._, Vol. LXI for 1823, p. 252;
W. Derham, for description of Auroras (in _Phil. Trans._ for
1728, p. 453); see, for Boscovitch, “Journal des Savants,”
February 1864; “Journal des Savants,” for August 1820; C.
H. Wilkinson, “Elements,” 1804; Vol. II. p. 279 and note;
Calogera’s “Raccolta,” XVII. 47, _Proc. of the Royal Soc. of
Edinburgh_ for the observations of J. A. Brown and others on
the aurora; F. C. Meyer, De luce boreali, 1726; Poggendorff, I.
135; Sturgeon, “Sc. Res.” 4th Sec. p. 489; _Phil. Trans._, Vol.
XXXVIII. p. 243; Vol. XLVI. p. 499; F. Zöllner’s paper in “L.
E. and D. Philos. Mag.,” for May and July, 1872; C. A. Young,
_Amer. Jour. of Sc_., Vol. III., 3rd s., p. 69; Baron Karl Von
Reichenbach’s “Physico-Physiological Researches,” trans. of Dr.
John Ashburner, London, 1851, pp. 5–36, also pp. 445, etc.,
of the translation of Dr. W. Gregory, London, 1850; J. H. Van
Swinden, “Recueil de Mémoires,” etc., La Haye, 1784, Vol. III.
p. 187, etc.; J. E. B. Wiedeburg, “Beobachtungen und Muth.,”
etc., 1771; G. W. Krafft, “Observ. Meteor,” etc., in _Novi Com.
Acad. Petrop._, Vol. V. p. 400; Giuseppe Toaldo, “Descrizione,”
etc., in _Saggi ... Accad. di Padova_, Vol. I. p. 178; Louis
Cotte, “Table of Auroræ, Observed ... 1768–1779,” Paris, 1783;
_Journal de Physique_ for 1775; _Recueil de Mem. de l’Acad. des
Sciences_ for 1769; A. S. Conti, “Rifflessioni sull’ Aurora
Boreale.”[48]

For _Auguste Arthur De la Rive_, consult “Bibl. Britan.,” Vol.
XVI, N.S., 1821, p. 201, likewise the “Annales de Chimie et de
Physique,” _Phil. Mag._, _Phil. Trans._, _Comptes Rendus_, more
especially, as well as the “Bibl. Univ.” and the “Mem. de la
Soc. de Genève,” at which latter place he was born in 1801.

For _Jean Jacques d’Ortons de Mairan_, consult “Mém. de Paris”
for the years 1726, 1731–1734, 1747, 1751, also abridgments of
the _Phil. Trans._ by Hutton, Vol. VII. p. 637, and by Baddam,
1745 ed., Vol. IX. pp. 490–497.

For _W. Derham_ (1657–1735) consult also “Nouv. Biog. Gen.”
(Hœfer), Vol. XIII. p. 712; the _Phil. Trans._ unabridged, Vol.
XXIV. for 1704–1705, pp. 2136–2138; Vol. XXXVI. pp. 137, 204,
also the following abridgments: Hutton, Vol. V. pp. 258–263;
Hy. Jones, Vol. IV. part ii. pp. 290–291; Baddam, Vol. IV. pp.
473–478. In the last-named volume is thus given an account
of Mr. Derham’s experiments: “He shows (_Phil. Trans._, No.
303, p. 2136) that, having consulted what others had writ of
magnets, he finds in Grimaldi’s _De Lumine et colore_ that both
he and M. De la Hire (_Phil. Trans._, No. 188) had hit upon
the same discovery before him.” Mr. Derham also alludes, more
particularly, to the observations of Ridley, Barlow and Dr.
Gilbert.

For _Claudius--Claes--Arrhenius_ (1627–1694) Swedish scientist,
professor at the Upsal University, consult “La Grande Encycl.,”
Vol. III. p. 1107; “Dict. Biog. Suédois,” Vol. XXII. pp. 385–389.

For _John Wallis_, the celebrated English mathematician
(1616–1703), in addition to the above-named _Phil. Trans._,
Vol. XXIII for 1702–1703, p. 1106, consult _Phil. Trans._, Vol.
XII for 1677, No. 135, pp. 863–866 (meteors), also the abridged
editions as follows: Hutton, Vol. IV. pp. 196, 639, 655; Hy.
Jones, Vol. IV. part ii. p. 286; Baddam, London, 1739, Vol. III.
p. 228 and Vol. IV. pp. 100–104 (mariner’s compass); “Nouv.
Biog. Gen.” (Hœfer), Vol. XLVI. p. 530.

AURORA AUSTRALIS, OR SOUTHERN POLAR LIGHT

The earliest account of this phenomenon was given by Don Antonio de Ulloa, as will be seen under date A.D. 1735–1746.

REFERENCES.--W. L. Krafft, “Observation,” etc., in _Acta Acad.
Petropol._ for 1778, Part I. Hist., p. 45; _Phil. Trans._, XLI.
pp. 840, 843; XLVI. pp. 319, 345; Chr. Hansteen, “On the Polar
Lights,” London, 1827.

ZODIACAL LIGHT

This phenomenon, from its occasional faint resemblance to and association with the auroras, would seem to deserve mention here, though none of the conjectures formed, more particularly by Cassini, Euler, Mairan, Kepler, Laplace, Fatio de Duiller, Schubert, Poisson, Olmsted, Biot, Herschel, Delambre, Olbers or Sir Wm. Thomson attribute to it any electric or magnetic origin.

In the _Report of the Proceedings of the Reale Istituto Lombardo_, 1876, however, appears the account of many observations confirmed by M. Serpieri which “demand absolutely” the conclusion that the zodiacal light “is an electrical aurora preceding and following the sun round the earth.”

Angstrom asserted that he observed the auroral line in the spectrum of the zodiacal light, and Lewis saw the latter during the aurora of May 2, 1877. Humboldt, who observed it (“Cosmos,” 1849, Vol. I. p. 126) in the Andes at an elevation of 13,000 to 15,000 feet, as well as on “the boundless grassy plains, the Llanos of Venezuela, and on the seashore, beneath the ever-clear sky of Cumana,” believes it to be caused by “a very compressed annulus of nebulous matter, revolving freely in space between the orbits of Venus and Mars.” In this connection he refers to Arago in the _Annuaire_ for 1832, p. 246, and to a letter published in _Comptes Rendus_, XVI, 1843, p. 687, from which the following is extracted: “Several physical facts appear to indicate that, in a mechanical separation of matter into its smallest particles, if the mass be very small in relation to the surface, the electrical tension may increase sufficiently for the production of light and heat.”

In Chambers’ “Descript. Astronomy,” p. 257, the historian Nicephorus is credited with first calling attention to the existence of this phenomenon, to which Giovanni Domenico Cassini gave the name of Zodiacal Light, after determining its relations in space during the year 1683 (_Mém. de l’Académie_, 1730, Tome VIII. pp. 188 and 276), but to Childrey belongs the credit of having given to Europe the first explicit description of this phenomenon at p. 183 of his 1661 “Britannia Baconica.”

REFERENCES.--Sturgeon’s _Annals_, etc., Vol. II. pp. 140–142;
Prof. C. W. Prichett’s paper in _Sci. Am. Supp._, No. 126, p.
2008, and the conclusions reached by Herr Gronemann (_Archives
Néerlandaises_) in _Sci. Am. Supp._, No. 327, p. 5221; Whewell,
“Hist. of the Ind. Sciences,” 1859, Vol. I. p. 531, and Vol. II.
p. 609; Tyndall, “Heat as a Mode of Motion,” 1873, pp. 57, 58,
497, 498; J. F. J. Schmidt, “Das Zodiacallicht,” Braunschweig,
1856; the very interesting abstract given in “The Journal of
the Brit. Assoc.,” Vol. XII. No. 5, of paper read by Rev. J.
T. W. Claridge, F.R.S., Jan. 9, 1902; Houzeau et Lancaster,
“Bibl. Générale,” Vol. II. 1882, pp. 763–771; “Pr. Roy. Soc. of
Edin.,” XX. pt. 3; C. Wilkes, “Theory of Zod. Light,” Philad.,
1857; _Phil. Trans._, Vol. XXXVIII. p. 249; “Cosmos,” 1849,
Vol. I. pp. 126–134; “Anc. Mém. de Paris,” I, VIII and X; J.
J. de Mairan, Paris, 1733; “U. S. Japan Expedition,” Vol. III,
Washington, 1856.

=A.D. 1684.=--Hooke (Dr. Robert), English natural philosopher (1635–1703), who, in 1677, had succeeded Oldenburg as Secretary to the Royal Society, gives the earliest well-defined plan of telegraphic transmission, in a paper addressed to the Royal Society “showing a way how to communicate one’s mind at great distances ... 40, 100, 120, etc., miles ... in as short a time almost as a man could write what he would have sent.” His apparatus consisted of an elevated framework supporting an open screen, behind which were suspended as many wooden devices, or symbols, such as circles, squares, triangles, etc., as there were letters in the alphabet. In the daytime these devices were drawn up by a rope behind the screen and made visible in the open space, while during the night use was made of torches, lanterns or lights.

Hooke also showed, in 1684, that iron and steel rods can be permanently magnetized by strongly heating them and by rapidly cooling them in the magnetic meridian (“Enc. Brit.” 1857, Vol. XIV. p. 3).

But, what is still more singular, he had, even previous to the above-named date (_i. e._ in 1667), alluded to the possibility of telephoning, that is, communicating sound through a wire. He thus expresses himself: “And as glasses have highly promoted our seeing, so it is not improbable that there may be found many mechanical inventions to improve our other senses--of hearing, smelling, tasting, touching.... ’Tis not impossible to hear a whisper a furlong’s distance, it having been already done; and perhaps the nature of the thing would not make it more impossible though that furlong should be ten times multiplied. And though some famous authors have affirmed it impossible to hear through the thinnest plates of Muscovy glass, I know a way by which it is easy to hear one speak through a wall a yard thick. It has not been examined how far acoustics may be improved, nor what other ways there may be of quickening our hearing, or conveying sound through other bodies than the air, for that is not the only medium. I can assure the reader that I have, by the help of a distended wire, propagated the sound to a very considerable distance in an instant, or with as seemingly quick a motion as that of light, at least, incomparably swifter than that which at the same time was propagated through the air; and this not only in a straight line, or direct, but in one bended in many angles.”

REFERENCES.--Hooke’s entire paper in Derham’s “Phil. Exp. and
Obs.” for 1726, pp. 142–150; _Phil. Trans_, for 1684; for his
observations on atmospheric electricity consult Houzeau et
Lancaster, “Bibl. Gén.,” Vol. II. p. 166; “Journal des Savants”
for April 1846; “The Posthumous Works of Robert Hooke,” London,
1705, p. 424; “Revue Scientifique,” Mars 15, 1902, p. 351;
for a complete list of all his works, consult Ward’s “Lives
of the Gresham Professors”; for description of his telegraph
and reference to Amontons, etc., see _Phil. Mag._, Vol. I. pp.
312–316.

=A.D. 1684.=--Sturmy’s “Mariner’s Magazine” for this year, of which a copy can be seen in the library of the British Museum, contains an account of the deviation of the compass and its tendency to give misleading directions on account of local attraction.

REFERENCES.--_Chambers’ Journal_, Vol. III. No. 60 for Feb.
24, 1855, p. 132, and Vol. XII. No. 300 for Oct. 1, 1859, p.
246; Capt. Sam. Sturmy’s “Magn. Virtues and Tides,” in _Phil.
Trans._, No. 57, p. 726, or “Memoirs of the Roy. Soc.,” Vol.
I. p. 134; _Phil. Trans._, abridgments: by Hutton, Vol. II. p.
560, and by Lowthorp, Vol. II. p. 609; “Journal des Sçavans” for
1683, Vol. XI. pp. 267–293.

=A.D. 1684.=--In the “Essayes of Natural Experiments made in the Accademia del Cimento” (Englished by Richard Waller), London, 1684, by direction of the Royal Society, there are given, respectively at pp. 53, 123 and 128–132, accounts of the operation of the magnet _in vacuo_, details of several magnetical experiments and experiments touching amber as well as other electrical bodies.

=A.D. 1686.=--Maimbourg (Louis), French historian, relates this instance of the employment of the magnet at Chap. VI of the Rev. W. Webster’s translation of his “Histoire de l’Arianisme”: “Whilst Valens (the Roman emperor) was at Antioch ... several pagans of distinction, with the philosophers ... not being able to bear that the empire should continue in the hands of the Christians, consulted privately the demons ... in order to know the destiny of the emperor and who should be his successor.... For this purpose they made a three-footed stool ... upon which, having laid a basin of divers metals, they placed the twenty-four letters of the alphabet around it; then one of these philosophers, who was a magician ... holding in one hand vervain and in the other a ring which hung at the end of a small thread, pronounced ... conjurations ... at which the three-footed stool turning around and the ring moving of itself, and turning from one side to the other over the letters, it caused them to fall upon the table ... which foretold them ... that the Furies were waiting for the emperor at Mimas; ... after which the enchanted ring, turning about again over the letters in order to express the name of him who should succeed the emperor, formed first of all these capital letters, T H E O. After adding a D, to form T H E O D, the ring stopped, and was not seen to move any more, at which one of the assistants cried out ... ‘Theodorus is the person whom the gods appoint for our emperor’” (“History of Christianity,” by the Rev. Henry Hart Milman, London, 1840, Vol. III. p. 120).

Maimbourg’s biography is given at p. 58, Vol. IV. of the “English Encyclopædia.”

=A.D. 1692.=--Dr. Le Lorrain de Vallemont relates, in “Description de l’Aimant,” etc., which he published at Paris, that, after a very severe wind and rain storm during the month of October 1690, the new steeple of the Church of Notre Dame de Chartres was found to be so seriously injured as to necessitate demolition. It was then observed that the iron cross was covered with a heavy coating of rust, which latter proved to be so highly magnetic that a special report upon it was made in the “Journal des Sçavans” by M. de la Hire, December 3, 1691, at the request of Giovanni Dom. Cassini, and of other members of the French Royal Academy.

REFERENCES.--“Journal des Sçavans,” Vols. XX, 1692, pp. 357–364
and Vol. XXXV, 1707, pp. 493–494 for additional accounts of
the Church of N. Dame de Chartres by M. de la Hire and M. de
Vallemont, and for a review of M. de Vallemont’s work, of which
latter pp. 4, 30, 66, 74, 89 to 90 merit special attention.

A.D. 1693.--Gregory (David), an eminent mathematician, who, in 1691, had been made Savilian Professor of Astronomy in Oxford mainly through the influence of Newton and Flamsteed, communicates the result of his observations on the laws of magnetic action.

REFERENCES.--Noad, “Manual of Electricity,” 1859, p. 525, _Phil.
Trans._, Vols. XVIII-XXV; “Biog. Générale,” Vol. XXI. p. 902;
Ninth “Britannica,” Vol. XI. p. 182; J. J. Fahie, “A History of
El. Tel. to the year 1837,” London, 1884, p. 24.

=A.D. 1693.=--In the first volume (Letter IV. pp. 25–28) of the “Memoirs for the Ingenious ...” by J. de la Crosse, are given accounts of several “New experiments on the loadstone; of a needle touch’d with it, and plac’d directly over the needle of a compass; of two Mariner’s Needles hang’d freely over one another, at several distances; of a touch’d steel-ring. Reasons of these experiments. The earth magnetical.”

In explanation of all this, M. de la Hire supposes “that the mass of the earth is a great loadstone, which directs the poles of the same name in all the loadstones and touch’d needles, towards the same place of the earth; so that the two hang’d needles do but remove from this natural position by the particular force they have of driving away each other’s poles of the same name; which force, in a certain degree, is not sufficient to overcome the power of the great loadstone of the earth.”

An account of M. P. de la Hire’s “new sort of a magnetical compass” had already appeared in the _Phil. Trans._ for 1686–1687, Vol. XVI. No. 188, p. 344.

REFERENCES.--For De la Hire, the following abridgments of the
_Phil. Trans._: Lowthorp, London, 1722, Vol. II. pp. 620–622;
Baddam, London, 1739, Vol. IV. pp. 473–478; Hutton, London,
1809, Vol. III. p. 381; also “The Phil. Hist. and Mem. of the
Roy. Acad. at Paris,” by Martyn and Chambers, London, 1742, Vol.
II. pp. 273–277; Vol. V. pp. 272–282 and the “Table Alphab. ...
Acad. Royale,” by M. Godin, Paris, Vol. II. p. 16 and Vol. X.
pp. 164 and 734.

=A.D. 1696.=--Zahn (F. Joannes), prebendary of the Prémontrés Order at Celle near Wurtzburg and provost of the convent of Niederzell, celebrated for his philosophical and mathematical studies, publishes his highly valued “Specula physico-mathematico-historica-notabilium ac mirabilium sciendorum ...” throughout the three folio volumes of which he treats extensively of the wonders of the entire universe.

In his tabulated list of the origin and properties of all the different known gems and stones (Vol. II. chap. vii. p. 55), he states that the loadstone, first discovered at Magnesia in Lydia (Caria--on the Mæander) is heavy, very well shaped, and of a dark colour verging upon blue. The marvellous properties of gems and stones are detailed at pp. 59–73 of the same volume, the fifth paragraph of Chap. VIII treating of the loadstone’s many virtues and admirable qualities, as exemplified in the writings of Guilielmus Gilbertus, Nicolaus Zucchius, Nicolaus Cabæus, Athanasius Kircherus, Eusebius Nierembergius, Laurentius Forerus, Hieronymus Dandinus, Jacobus Grandamicus, Ludovicus Alcazar, Claudius Franciscus Milliet de Chales, as well as of many others.

REFERENCES.--Michaud, “Biog. Univ.,” Vol. XLV. p. 340; Dr. John
Thomas, “Universal Pron. Dict.,” 1886, p. 2514; Brunet, “Manuel
du Libraire,” Vol. V. p. 1519.

=A.D. 1700.=--Bernoulli (John I), son of Nicolas, the founder of the celebrated family of that name, improves upon Picard’s discovery of the electrical appearance of the barometer, made A.D. 1675, by devising a mercurial phosphorus or mercury shining _in vacuo_ (“Diss. Physica de Mercurio Lucente,” etc., Basel, 1719). This procured the favourable notice of King Frederick I, of Prussia, who rewarded him with a medal. John Bernoulli I (1667–1748) was a member of nearly every learned society of Europe and “one of the first mathematicians of a mathematical age.” His exceedingly valuable memoirs, found in all the scientific transactions of the day, were first collected in their entirety during the year 1742, by Cramer, Professor of Mathematics, and published at Lausanne and Geneva.

“Is it not surprising,” remarks Prof. Robison, in his able article on “Dynamics” (Eighth “Britannica,” Vol. VIII. p. 363), “that, twenty-five years after the publication of Newton’s ‘Principia,’ a mathematician on the Continent should publish a solution in the Memoirs of the French Academy, and boast that he had given the first demonstration of it? Yet, John Bernoulli did this in 1710. Is it not more remarkable that this should be precisely the solution given by Newton, beginning from the same theorem, the 40th I., Prin., following Newton in every step and using the same subsidiary lines? Yet, so it is.” This was five years after he had accepted (1705) the chair of mathematics made vacant by the death of his brother, James I.

BERNOULLI FAMILY

The Bernoulli family is as well known in the history of mathematics, by the distinguished services of eight of its members, as is the Cassini family through the successes achieved by four of its representatives in the development of astronomical studies.

Daniel Bernoulli (1700–1782), second son of John I, constructed a dipping needle, which is described on p. 85 of the Eighth “Britannica,” Vol. XIV, and with which he observed the dip to diminish half a degree during an earthquake in the year 1767. Before Daniel was twenty-four years old he had declined the Presidency of the Academy of Sciences at Genoa, and, at the age of twenty-five, was appointed Professor of Mathematics at St. Petersburg.

John Bernoulli II (1710–1790), youngest of the three sons of John I, gained three prizes from the French Academy of Sciences for Memoirs on the Capstan, on the Propagation of Light and on the Magnet.

John Bernoulli III (1744–1807), grandson of John I, took the degree of Doctor of Philosophy at the age of thirteen, and, when nineteen years old, was appointed Astronomer Royal of Berlin. He published several volumes of travels, in one of which he relates (A. L. Ternant, “Le Télégraphe,” 1881, p. 32) that he saw, in the last-named city, an instrument constructed of five bells, with which all letters of the alphabet could be expressed.

James Bernoulli I (1654–1705), brother of John I, while at London, was introduced into the philosophical meetings of Boyle, Hooke, Edward Stillingfleet and other learned and scientific men. He opened, in 1682, the _Collegium Experimentale Physico-Mechanicum_ for public instruction, but his lasting fame dates from the year 1684, when the great Von Leibnitz published his treatise “De Gravitate Ætheris.” Three years later, in 1687, James occupied the mathematical chair of the University of Basel, made vacant by the death of the learned Megerlin.

REFERENCES.--Whewell, “Hist. of the Inductive Sciences,” 1859,
Vol. I. pp. 358–366, 375–380, 393, 430, and Vol. II. pp. 32–39,
42; “Hist. de l’Acad. Royale des Sciences,” 1700–1707; Edin.
“Encycl.,” 1813, Vol. III. pp. 464–470; “Med. Library and
Historical Journal,” New York, 1903, Vol. I. pp. 270–277.

For Bernoulli family see “Histoire des Sc. Math. et Phys.,”
Maxim. Marie, Paris, 1888, Vols. VII-XI; “Geschichte der
Mathemathik,” Moritz Canton, Leipzig, 1898, Vol. III. pp.
207–261; “Histoire Générale des Mathématiques,” Chas. Bossut,
Paris, 1810, Vol. II. s. 2, as at table, p. 512. See the family
tree in “Eng. Cycl.,” Vol. VI. p. 972, and all the Bernoullis at
p. 84 of Vol. II, Houzeau et Lancaster’s “Bibl. Gén.,” 1882.

=A.D. 1700.=--Morgagni (Giovanni Battista), while practising medicine at Bologna and at Venice, uses the magnet to remove particles of iron which had accidentally fallen into the eyes, exactly in the same manner as Kirkringius and Fabricius Hildanus had done before him.

REFERENCES.--Maunder’s “Biog. Treasury”; also Beckmann’s
“History of Inventions,” Vol. I. p. 44, and biography in
Larousse, Vol. XI, as well as in Vol. XVI of the Ninth
“Britannica.”

=A.D. 1700.=--Duverney (Joseph Guichard), an eminent French anatomist, knew at this date that the limbs of a frog are convulsed by the electric current (as shown in the “Histoire de l’Académie des Sciences,” 1700, p. 40, and 1742, vol. I. p. 187), and the Italian physician L. Marco Antonio Caldani, assistant to Morgagni, alludes to the “revival of frogs by electrical discharges.”

REFERENCES.--“Ency. Metrop.,” Vol. IV. p. 220; Highton’s “Elect.
Tel.”; Fahie, “Hist. of Elec. Tel.,” pp. 175 and 176 and notes;
Knight’s “Mech. Dict.,” Vol. II. p. 936; G. H. Browne, London,
1704, and in “Phil. Mag.,” Vol. XVIII. p. 285, also note p. 83
of Ronalds’ “Catalogue.”

=A.D. 1701–1702.=--Le Brun (Pierre), French theologian (1661–1729), publishes his “Histoire Critique des Pratiques Superstitieuses,” wherein he makes mention (Vol. I. p. 294) of the possibility of transmitting intelligence in the manner indicated by the Jesuit Leurechon.

He is also the author of “Lettres qui découvrent l’illusion des philosophes sur la baguette divinatoire,” Paris, 1693 (Larousse’s “Dictionnaire,” Tome X. p. 292).

=A.D. 1702.=--Bion (Nicolas), French engineer and manufacturer of mathematical and astronomical instruments (1652–1733), is the author of “Usage des Astrolabes,” which was shortly after followed by his well-known “Traité de la construction et des principaux usages des instruments de mathématique.” In the preparation of the last named, which was translated into German (Leipzig, 1713, Nuremberg, 1721) as well as into English (London, 1723, 1738), Bion admits the assistance afforded him by Lahire, Cassini and Delisle the younger.

The whole of Book VII (pp. 267–290) of the “Traité,” is devoted to the description of instruments employed in navigation, the compass and the astrolabe in particular, with instructions for ascertaining the declination and variation.

Bion is also the author of “L’Usage des Globes Célestes et Terrestres et des sphères suivant les differents systèmes du monde,” Amsterdam, 1700. Much of the matter, however, is said to have been copied by Bion from Pierre Polinière’s “Expériences de Phisique,” of which latter five editions were printed respectively in 1709, 1718, 1728, 1734 and 1741.

REFERENCES.--“La Grande Encycl.,” Vol. VI. p. 897; Michaud,
“Biog. Univ.,” Vol. IV. p. 354; Dr. J. Thomas, “Univ. Pr.
Dict.,” 1886, p. 386.

=A.D. 1702.=--Marcel (Arnold), Commissioner of the Navy at Arles, publishes a pamphlet dedicated to the King, and entitled “The Art of Making Signals, both by Sea and by Land,” wherein he affirms that he has “communicated frequently at the distance of two leagues (in as short a space of time as a man could write down and form exactly the letters contained in the advice he would communicate), an unexpected piece of news that took up a page in writing.” The particulars of this invention are, however, wanting.

Marcel reports many well-authenticated instances where, as already mentioned by Mæstro Giulio Cæsare (A.D. 1590), iron bars have become temporarily magnetic by position alone.

REFERENCES.--Snow Harris, “Rudim. Mag.,” I and II. pp. 91,
92; also “Emporium of Arts and Sciences,” 1812, Vol. I. p.
301; _Phil. Trans._, Vol. XXXVII. p. 294, also the following
abridgments: Baddam, Vol. IX, 1745, p. 278; Eames and Martyn,
Vol. VI. part. ii. p. 270; Hutton, Vol. VII. p. 540.

=A.D. 1702.=--Kæmpfer (Engelbrecht), German physician and naturalist (1651–1716), describes in his “Amœnitates Exoticæ,” experiments made by him upon the electric _torpedo_ (Leithead, 1837, Chap. XII). He insists that any person may avoid all sensation of the shock by merely holding the breath while touching the animal. This apparently improbable fact has since been confirmed, however, by many scientists; the accurate observations of Mr. Walsh (A.D. 1773) on the subject, reported in the _Phil. Trans._ for 1773–1774–1775, claiming especial attention (Larousse, “Dict.,” Vol. IX. p. 1144).

=A.D. 1704.=--Amontons (Guillaume), an ingenious mechanician and scientist, exhibits before the royal family of France, and before the members of the Académie des Sciences, his system of communicating intelligence between distant points through the agency of magnifying glasses--telescopes. The “Mémoires de l’Académie,” 1698–1705, contain an account of his many scientific productions.

REFERENCES.--Larousse, “Dict.,” Vol. I. pp. 282–283; Appleton’s
“Cyclop.,” Vol. I. p. 432.

=A.D. 1705.=--Witson (Nicholaes), Burgomaster of Amsterdam, announces at p. 56 of his “Noord en Oost Tartarye,” that the nautical compass was in use by the Coreans in the second half of the seventeenth century.

=A.D. 1705.=--Hauksbee (Francis), English natural philosopher and Curator of the Royal Society, makes, before the latter, several experiments on the _mercurial phosphorus_. He shows that a considerable quantity of light can be produced by agitating mercury in partly exhausted as well as in thoroughly exhausted glass vessels. When the mercury is made to break into a shower, flashes of light are seen to start everywhere “in as strange a form as lightning.”

He also showed light _in vacuo_ produced by rubbing amber and by rubbing glass upon woollen. He says (Priestley, “Hist. and Present State of Electricity,” London, 1775, p. 19) that every fresh glass first gave a purple and then a pale light, and that woollen, tinctured with salt or spirits, produced a new, strong and fulgurating light.

Hauksbee constructed a powerful electrical machine wherein the Von Guericke sulphur globe was replaced by one of glass, as had already been done by Sir Isaac Newton (at A.D. 1675). With it he found that upon exhausting the air, whirling the globe rapidly and placing his hand upon the outside, a strong light appeared upon the interior, and that the light would show itself also upon the outside when air was let into the globe (“Physico-Mech. Exp.,” pp. 12, 14, 26, 32, 34).

The machine, which the celebrated mechanician Leupold had constructed at Leipzig for Mr. Wolfius, only differed from the original one made by Hauksbee in that the glass globe turned vertically instead of horizontally.

Other experiments with coated glass globes, globes of sulphur, etc., are detailed in the “Physico-Mech. Exp.,” as indicated at pp. 21–24 the Priestley work above alluded to. At the last-named page he says: “That Mr. Hauksbee, after all, had no clear idea of the distinction of bodies into electrics and non-electrics appears from some of his last experiments, in which he attempted to produce electrical appearances from metals, and from the reasons he gives for his want of success in those attempts.”

Hauksbee also gave some attention to the study of the laws of magnetic force, and the results published in the _Phil. Trans._, Vol. XXVII. for 1710–1712, p. 506, giving a law of force varying as the sesqui-duplicate ratio of the distances, were subsequently confirmed by Taylor and by Whiston in the _Phil. Trans._ for 1721 (Noad, “Manual of Elec.,” 1859, p. 579).

REFERENCES.--Aglave et Boulard, “Lumière Electrique,” Paris,
1882, p. 18; Priestley, “Familiar Intr. to Study of Elec.,”
London, 1786, p. 60; _Phil. Trans._, Vol. XXV. pp. 2327, 2332;
Vol. XXVI, 1708–1709, pp. 82–92; Vol. XXIX, 1714–1716, p. 294
(with Brooke Taylor); also the following abridgments: Hutton,
Vol. V. pp. 270, 307, 324, 344, 355, 411–416, 452, 509, 528,
696; Jones, Vol. IV. p. 295; Baddam, 1745, Vol. V. pp. 33–37,
41–43, 112, 114–117, 483; Thos. Thomson, “Hist. of the Roy.
Soc.,” London, 1812, p. 430; _Chemical News_, Vol. II. p. 147;
Nicolas Desmarets, “Expériences,” etc., Paris, 1754, in “Recueil
des Mémoires de l’Acad. des Sciences.”