Chapter XXIX: Part II: pp. 254–256, 279, for some of his other correspondence (6)

It is not within the scope of this “Bibliographical History” to describe Davy’s other notable papers relative to the miner’s safety lamp, etc., but reference should be made here to his first scientific memoir, “On heat, light and the combination of light” (Sir H. Davy’s works, Vol. II) of which copious extracts are given by Prof. John Tyndall in the appendix to his third lecture on “Heat considered as a mode of motion.”

As regards the caloric theory, which had deservedly been engaging the attention of so many scientists, it is, however, thought best to quote here from Deschanel’s article on thermo-dynamics: “Strange to say, this theory survived the many exposures of its weakness and the, if possible, still more conclusive experiment of Sir Humphry Davy, who showed that two pieces of ice, when rubbed together, were converted into water, a change which involves not the evolution but the absorption of latent heat, and which cannot be explained by diminution of thermal capacity, since the specific heat of water is much greater than that of ice. Davy, like Rumford, maintained that heat consisted in motion, and the same view was maintained by Dr. Thomas Young; but the doctrine of caloric nevertheless continued to be generally adopted until about the year 1840, since which time the experiments of Joule, the eloquent advocacy of Meyer, and the mathematical deductions of Thomson, Rankine and Clausius, have completely established the mechanical theory of heat, and built up an accurate science of thermo-dynamics.”

REFERENCES.--“The Life of Sir H. Davy,” by John Ayrton Paris,
M.D., 1831, and by T. E. Thorpe, New York, 1896, also his life
by Dr. John Davy, F.R.S., 1836; and his biography and articles
“Chemistry” and “Voltaic Electricity” in the “Encyclopædia
Britannica”; “Works of Sir Humphry Davy,” edited by John Davy,
1839–1840; “The Fragmentary Remains ... of Sir H. Davy,” 1858;
“Dic. Tech. et Prat. d’Electricité” de Mr. Geo. Durant, Paris,
1887–1889; W. T. Brande, “Manual of Chemistry,” London, 1848,
Vol. I. pp. xciii-cv, 213–224; C. H. Wilkinson, “Elements of
Galvanism,” London, 1804, Vol. II. pp. 80–86, and Chap. XXVII;
Thomas Thomson, “History of the Royal Society,” London, 1812,
pp. 454–455; “Galvanism,” in Dr. Lardner’s Lectures; Noad’s
“Lectures on Chemistry,” pp. 32–33; Bakewell’s “Elec. Sc.,” pp.
33–35; Daniel Davis, “Manual of Magnetism,” 1846–1852; Thomson,
“History of Chemistry,” Vol. II. pp. 260–261; “Elem. of Exp.
Chem.,” Wm. Henry, London, 1823, Vol. I. p. 192; “Elements of
Chemical Philosophy,” p. 155; Thomas Thomson, M.D., London,
1830; “Outline of the Sciences of Heat and Electricity,”
pp. 467, et. seq., 491–495, 533; De la Rive’s “Treatise
on Electricity ...” Vol. II. pp. 282–283; “Encyclopedia
Metropolitana,” Vol. IV (Galv.), pp. 176, 178, 222, and (Elec.
Mag.) pp. 9 and 10; Gay-Lussac and Thénard, _Phil. Mag._, Vol.
XXXII. p. 88, 1809; Jacquin, _Phil. Mag._, Vol. XXXVI. p. 73,
1810; M. Donovan, _Phil. Mag._, Vol. XXII. pp. 227, 245, 1811;
M. Yatman, “A Letter ...” and Davy’s “Enquiries ...” London,
1811, 1814; W. Henry, “On Sir H. Davy and Dr. Wollaston,”
London, 1830; Contessi G. Lelandri, “Ann. Reg. Lomb., Veneto,”
11, 78, 1832, and F. I. Roux, “Conservation des plaques ...”
Paris, 1866; _Nicholson’s Journal_, 4to, Vol. IV. pp. 275, 337
and 394; and 8vo., Vol. I. p. 144, Vol. III. p. 135; Dredge,
“Electric Illumination,” Vol. I. pp. 24, 25, 30; _Phil. Mag._,
Vol. VII. p. 347, for experiments of Dr. Henry Moyes, also Vol.
XI. pp. 302, 326; XXVIII. pp. 3, 104, 220; XXIX. p. 372; XXXI.
p. 3; XXXII. pp. 1, 18–22, 101, 146, 193; XXXIII. p. 479; XXXV.
p. 401; XXXVI. pp. 17, 85, 352, 404; XL. p. 145; LVIII. pp. 43,
406; LIX. p. 468; LX. p. 179; _Phil. Mag. or Annals_, Vols. I.
pp. 31, 94, 190; VI. p. 81; X. pp. 214, 379, 426; _Phil. Trans._
for 1801, 1809, 1810, 1822; Sturgeon’s “Scientific Researches,”
Bury, 1850, pp. 14–16, 23; _Annales de Chimie_, Vol. XV. p.
113; “Société Philomathique,” An. X. p. 111; Becquerel, Paris,
1850, Vol. I. pp. xi and 33 note; “Nuova Scelta d’Opusc.” Vol.
II. pp. 190, 282; “Beiträge zur Erweiterung,” etc., Berlin,
1820; “Elemente d. Chemischen,” etc., Berlin, 1814; “Royal
Society Catalogue of Scientific Papers,” London, 1868, Vol.
II. pp. 171–175; “Biographie Générale,” Vol. XIII. p. 264;
“Engineering,” London, Vol. LII. p. 759; “Abstracts of Papers
... Roy. Soc.,” London, 1832–1833, Vol. I. pp. 59, 247, 278,
313, 350; Vol. II. pp. 154, 159, 189, 213, 242, 281, 354; “Royal
Society Catalogue of Scientific Papers,” Vol. II. pp. 175–180,
and Vol. VI. p. 633 (likewise Vol. VII. pp. 494–495--for John
Davy); “Bibliothèque Britannique,” Vol. XVII for 1801, pp. 237,
246; Vol. XXV, N.S. for 1824, p. 98; Vol. XXXIV, O.S. for 1807,
p. 397 (the same as “Nicholson’s Journal,” for January 1807);
Vol. XXXV. pp. 16, 141; “Edin. Phil. Journ.,” Vol. X. p. 185.

Of the afore-named references in the _Phil. Magazine_, Vol. XXXI, that at p. 3 relates to Davy’s new Eudiometer acting by the electric spark exactly in the same manner as that of Il Marchese de Brezé, described in the “Opuscoli.”

=A.D. 1801.=--Flinders (Matthew), a very able navigator and captain in the English merchant service, sails in the bark “Investigator” for the purpose of circumnavigating and exploring New Holland. During this memorable voyage he carefully observed the cause of errors in the variation of the magnetic needle as depending on the direction in azimuth of the ship’s head, having often noticed, as a writer in the English _Quarterly Review_ expresses it (Vol. CXVIII. p. 343), that the direction of the compass needle frequently wandered from that which the known variation due to the geographical position of the ship assigned to it. To correct those disturbances he suggested placing aft of the compass a vertical bar of soft iron, whose upper end, having like magnetism as the imaginary mass in the ship’s head, would, in acting on the opposite pole of the compass needle, rectify its disturbances.

Flinders had, during the year 1795, made observations in the same line as those recorded by the astronomer Bayly, who had sailed with Captain Cook during his last two voyages, but it was not until his return from the unfortunate first voyage above alluded to that he properly recorded his investigations for the benefit of navigators.

REFERENCES.--“Encyclopædia Britannica,” 1856, Vol. X. p. 295,
and article “Australia,” Vol. IV. pp. 253, 254; “English
Cyclopædia” (Biography), Vol. II. pp. 933–935; _Sci. Am. Supp._,
No. 534, p. 8526; William Walker, “The Magnetism of Ships,”
London, 1833, pp. 21–23; “Abstracts of Papers of the _Phil.
Trans._, 1800–1830,” p. 187; _Phil. Trans._ for 1805; John
Farrar, “Elem. of Elect.,” 1826, p. 381; “Cat. Sc. Papers Royal
Soc.,” Vol. I. p. 187.

=A.D. 1801.=--Gautherot (Nicholas), able French chemist (1753–1803), discovers that when a current has passed through two plates or wires of the same metal in dilute sulphuric acid, a secondary, reverse or polarization current is obtainable after disconnecting the battery. This was the first step in the storage of electricity and an account is given of it in the _Philosophical Magazine_, Vol. XXIV. pp. 185–186, which contains a report of the proceedings before the Galvani Society of Paris. Gautherot says that the results he obtained should become the source or basis of several other experiments, and concur more than any other to the discovery of the theory of this new branch of physics.

In this same year Gautherot observed the power of adhesion of the two wires in contact with the upper and lower ends of the pile, a report upon which appears at p. 209, Vol. XXXIX of the _Annales de Chimie_, while a full account of his observations on the subject forms the substance of a separate work printed in London during the year 1828.

The French physicist, C. J. Lehot, makes allusion to the last-named discovery in the following words, at p. 4 of his pamphlet entitled “Observations sur le Galvanisme et le Magnétisme”:

“It has long been known that the two wires which terminate a pile attract one another, and, after contact, adhere like two magnets. This attraction between the two wires, one of which receives, and the other loses, the galvanic fluid, differs essentially from electrical attraction, as Ritter observed, since it is not followed by a repulsion after contact, but continues as long as the chain is closed.”

J. J. Fahie, who also quotes this passage, says:

“The discovery in question seems to have been made independently, and at about the same time by Gautherot (_Philosophical Magazine_ or _Annals_ for 1828, Vol. IV. p. 458), by P. S. Laplace, and by J. B. Biot (_Journal de Physique et de Chimie_, for 1801, Vol. LIII. p. 266). The latter made the further very acute observation that, if the wires are attached to plates of metal, and these plates approached by their edges, they will attract one another; while if approached by their faces no action whatever takes place. For other interesting experiments of this kind see ‘Nicholson’s Journal’ for 1804, Vol. VII. p. 304.”

Previous to the aforesaid discoveries, on the 12th Brumaire, An. IX (Nov. 1800), Gautherot had published his refutation of Volta’s contact theory, through the Paris “Société Philotechnique,” and it is to be found recorded at p. 471, Vol. I of the “Mémoires des Sociétés Savantes et Littéraires de la République Française.”

Later on he devoted so much attention to galvanic researches that Messrs. A. F. de Fourcroy and L. N. Vauquelin made a special report upon the five important memoirs containing the results of his many observations to the French Institute on the 21st Fructidor.

The first memoir gives the whole theory and practice of the various kinds of conductors, and describes an apparatus devised by Gautherot to ascertain the conducting powers of different natural, solid, liquid and even gaseous bodies (Izarn, “Manuel du Galvanisme” 1804, pp. 56–60). He enters into full details as to the effects of the voltaic pile in many experiments made upon himself, and draws consequences which apparently disprove the identity of the electric and the galvanic fluids.

The second memoir treats of the galvanic properties of charcoal, and shows that it is a less perfect conductor than are metallic substances.

In the third memoir he makes known his discovery that charcoal and zinc form a galvanic apparatus which will produce shocks, the decomposition of water, etc. He observes “that in the decomposition of water, charcoal decomposes that fluid in the same way with non-oxydable metals; or, in other words, that when two pieces of charcoal are employed for this purpose, one of them disengages the hydrogen gas, and the other the oxygen ... when the portions of charcoal touch each other in the water, its decomposition is not stopped on that account, as happens when metallic substances are brought in contact under the same circumstances. Indeed, if to bring more immediately together, one of the pieces of charcoal be cut in a furcated shape, this does not become an obstacle to the decomposition of the water.”

The fourth memoir treats further of different kinds of conductors, and of various methods of constructing galvanic columns.

In the fifth and last memoir, Gautherot relates his important discovery that an effective galvanic apparatus can be made without metals. He constructed one of forty layers of charcoal and plumbago, which communicated a strong and pungent taste, accompanied by the galvanic flash of light, and which finally produced the decomposition of water, the charcoal side disengaging the hydrogen gas (Izarn, “Manuel du Galvanisme,” 1804, p. 177).

During the month of March 1803, he read before the “Institut National” a memoir entitled “Recherches,” etc. (researches upon the causes which develop electricity in the galvanic apparatus). This appeared in the _Journal de Physique_, Vol. LVI. p. 429.

REFERENCES.--“Biographie Générale,” Vol. XIX. p. 694; Larousse,
“Dict. Univ.,” Vol. VIII. p. 1089; Izarn, Giuseppe (Joseph)
“Manuel du Galvanisme,” Paris, An. XII. 1804, s. 6, pp. 95,
250–254: _Mém. des Soc. Savantes_, etc., Vol. I. pp. 164,
168; P. Sue, aîné, “Hist. du Galvanisme,” Paris, An. X, 1802,
Vol. II. pp. 191, 196–203, 213, 214, 316; Alglave et Boulard,
_Lumière Electrique_, Paris, 1882, p. 219; _Poggendorff_,
Vol. I. p. 857; “Extrait d’une lettre de Brugnatelli,” etc.,
Bruxelles, 1802 (Van Mons, _Journal de Chimie_, Vol. II. p. 216).

=A.D. 1801.=--Robertson (Etienne Gaspard), a very capable French experimentalist and one of the founders of the Paris Galvani Society, who has already been alluded to in the article relating to Sir Humphry Davy, writes a memoir, “Expériences nouvelles sur le fluide galvanique,” which was read before the Institute on the 11th Fructidor, An. VIII, and which appeared in the _Annales de Chimie_ (Vol. XXXVII. p. 132), as well as in the “Mémoires Récréatifs, Scientifiques,” etc., published in Paris during 1840, three years after Robertson’s death.

Robertson states that as he was delivering a lecture on the 9th Vendémaire, An. IX, during which he alluded to differences which he found to exist between the galvanic and electric fluids, he was interrupted by Prof. Brugnatelli, who stated that Volta, who was then present, desired an opportunity to correct the wrong impressions the lecturer laboured under. Volta called upon him early the day following and brought a live frog as well as apparatus, with which they experimented quite extensively, and the results of which brought Robertson completely over to the views of the Italian scientist. Volta frequently repeated his visits, which led to the development of a lasting friendship between the two. They visited together all the prominent scientific bodies, such as l’Ecole de Médecine, l’Ecole Polytechnique, etc., but found to their great astonishment that Robertson was the only one in Paris who had as yet given the new discovery any serious attention. At pp. 250–253, Vol. I of his “Mémoires,” etc., will be found a full account of the above as well as of the very indifferent reception first given them by the celebrated Prof. Charles.

Robertson adds (p. 256 of last-named work) that he was asked by Volta to witness the latter’s notable experiments made before the members of the National Institute of France, Nov. 16, 18, 20, 1800, and already alluded to herein at A.D. 1775. The sessions of that body were being held at the time in the Palais du Louvre, and the excitement caused by the meetings was so great that all the approaches were guarded by soldiery. After Prof. Volta had explained his theory and alluded to the identity of electricity and galvanism, he announced that Robertson had first illustrated the fact, and he asked him to repeat his original experiment, which the latter did after the necessary hydrogen gas had been procured from the neighbouring cabinet of Prof. Charles.

Robertson is also the author of several other interesting memoirs on the electrophorus, the improved “couronne de tasses” and “acide galvanique” which can be found in Vol. XXXVII of the _Journal de Physique_ and in the _Journal de Paris_ for the year 1800 (“Recueil des Actes de la Soc. de Lyon,” Tome II. p. 370).

=A.D. 1801.=--Gerboin (A. C.), Professor at the Medical School of Strasbourg, is the first to report upon the peculiar agitation of mercury when the voltaic current passes through it.

He states, in his “Recherches expérimentales sur un nouveau mode de l’action électrique” (Strasbourg, 1808), that his many researches were instigated by the observation he had made during the winter of 1798, while in company with some friends watching a child play with a hollow wooden ball. The Italian physicist, Abbate Fortis (1740–1803), who wrote several works on natural philosophy, but who is best known by his “Viaggio di Dalmazia,” had already announced that a pyritical cube suspended by a thread held between the thumb and index would immediately, without any movement of the fingers, assume a circular motion upon being approached by another body. The “Morgenblatt” of Tübingen and the French “Archives Littéraires” render in 1807 a very complete account of Ritter’s researches upon the Fortis pendulum, and N. Meissas states, at pp. 181–187 of his “Nouveaux Eléments de Physique,” Paris, 1838, that he repeated the experiment of Ritter and of his friend Gerboin and observed many very curious results. These he embodied in a communication during the month of April 1829 to Ampère, who looked into Meissas’ work in company with M. Becquerel, also a member of the French Institute.

In his experiments, Gerboin employed a tube bent in U[ symbol] form, filled half full of mercury, which later was covered with a stratum of water, and he placed therein the wires connecting with a pile. The surface of the mercury beneath the negative pole was slightly oxidized, but the surface under the positive point moved so violently as to cause small bodies placed within to be thrown outward upon the surface of the tube. These bodies moved in a contrary direction, v from the circumference toward the interior, if the positive pole was made to touch the liquid metal.

REFERENCES.--Observations of M. Erman, of the Berlin Academy of
Sciences, upon M. Gerboin’s experiments related in the _Annales
de Chimie_, Tome LXXVII. p. 32. Also, _Annales de Chimie_, Tome
XLI. pp. 196, 197, _Mém. des Soc. Sav. et Lit._, Vol. II. p.
199; Dr. Gore, “El. Metal,” 1877, p. 3; De la Rive, “Treatise on
Electricity,” 1856, Vol. II. p. 433; Gmelin’s “Chemistry,” Vol.
I. p. 487.

=A.D. 1801.=--Trommsdorff (Johann Bartholomäus), German chemist and pharmacist, who became Professor of Physics and Chemistry in the University of Erfurt, discovers that by employing large plates in galvanic batteries he can produce the combustion of fine wires and of thin leaves of metal.

After having obtained very strong shocks and large sparks, and effected the decomposition of water, etc., with his first pile consisting of 180 discs of copper, zinc and wet cardboard, he experimented with very thin leaves of the following metals, and found them to burn as follows: Gold, with a bright white light; silver, with a blue light; yellow copper, with a reddish blue light; red copper, with an emerald blue flame; zinc, with a bluish white flame; tin, with a reddish white light, etc. When oxidizing the noble or perfect metals, gold, silver, platinum, in hollow glass spheres, he found them to melt so thoroughly as to completely line the sides of the latter.

Trommsdorff afterward constructed a much larger pile of nearly 600 discs, not doubting that with a larger apparatus he could consume very thick plates. It was while carrying on subsequent experiments that MM. Fourcroy, Vauquelin and Thénard ascertained the fact that metals were more effectively deflagrated by piles with large plates than by piles having a great many plates of smaller surfaces.

In a letter dated Erfurt, March 16, 1801, Trommsdorff alludes to the galvanic decomposition of water spoken of at p. 98 of the “Archives du Nord pour la Physique et la Médecine,” published at Copenhagen, and expresses doubts as to the correctness of the conclusions therein pointed out by Pfaff and Ritter.

REFERENCES.--“Encycl. Metrop.” (Galvanism), Vol. IV. p. 221;
“Roy. Soc. Sci. Papers,” Vol. VI. pp. 45–52; _Poggendorff_, Vol.
II. pp. 1136, 1137; C. H. Wilkinson, “Elem. of Galv.,” London,
1804, Vol. II. pp. 134–136; J. S. Ersch, “Handbuch,” etc., p.
119; L. F. F. Crell, “Chemische Annalen” for 1801; 4^e Cah.,
p. 337; J. B. Van Mons, _Journal de Chimie_, Vol. I. p. 41;
Larousse, “Dict. Univ.,” Vol. XV. p. 535. His pile is described
at pp. 253–254, Vol. II of “Hist. du Galvanisme,” P. Sue, aîné,
Paris, An. X, 1802, with references to Von Crell’s “Chemische
Annalen,” 1801, 4th Book, p. 237, and Van Mons’ “Journal de
Chimie,” Vol. I. p. 41.

=A.D. 1801.=--Libes (Antoine), Professor of Natural Philosophy at the Collège de Beziers and at the Paris Ecole Normale and Lycée Charlemagne, publishes in three volumes, at Paris, his “Traité élémentaire de Physique,” which had been preceded by his “Théorie de l’électricité,” etc., and was followed by a valuable “Dictionnaire de Physique” in 1806 (C. F. V. Delaunay, “Manuel,” etc., Paris, 1809).

In his “Traité,” Prof. Libes dispels the previous generally accepted belief as to the production of electricity by pressure. Experiments made by Æpinus and by Haüy had shown that such minerals as developed positive electricity by friction likewise exhibited the same electricity by pressure, and that those furnishing resinous or negative electricity by pressure developed the same electricity by friction.

It is known that varnished silk (_taffetas gommé_) acquires resinous electricity by ordinary friction, but Libes found the means of causing it to develop vitreous or positive electricity. This is shown when a metallic disc insulated by a glass handle is _pressed_ upon the silk; the latter will acquire positive electricity while the disc will develop resinous or negative electricity. If, on the contrary, the disc is _rubbed_ or _rolled_ upon the silk so as to produce friction, the silk acquires resinous electricity and the disc vitreous or positive electricity. If a glass plate is substituted for the disc, the silk again acquires vitreous electricity and the glass resinous electricity, that is to say, they both develop contrary electricities to that furnished through ordinary rubbing.

REFERENCES.--Larousse, “Dict. Univ.,” Vol. X. p. 475;
_Poggendorff_, Vol. I. pp. 1449, 1450; Volpicelli, “Sul
cognito fenomeno ...” Roma, 1859; Haüy, “Traité Elémentaire de
Physique,” Paris, 1806, Vol. I. pp. 371, 372; A. C. Becquerel,
“Expériences ... par la pression,” Paris, 1823; “Catal. of Sci.
Papers of Roy. Soc.,” Vol. IV. p. 5; Thos. Thomson, “An Outline
of the Sciences of Heat and Electricity,” London and Edinburgh,
1830, p. 482; Dove, p. 229; “Encycl. Brit.,” Vol. VIII, 1855, p.
563; _Annales de Chimie et de Physique_, Vol. XXII. p. 5; _Phil.
Mag._, Vol. LXII. pp. 204, 263.

=A.D. 1801.=--Fourcroy (Antoine François de), an eminent French chemist, physician and author, who succeeded Macquer in the professorship at the Jardin du Roi, for which Lavoisier was likewise a candidate, publishes (Vol. XXXIX. p. 103, of the _Annales de Chimie_) the result of galvanic experiments which he made in conjunction with Louis Nicholas Vauquelin (1763–1829), and also with Baron Louis Jacques Thénard (1777–1857), who, in turn, became the successor of Fourcroy as Professor of Chemistry at the Ecole Polytechnique. They thought that by using many discs they could increase the force of the current and also decompose water more rapidly, but found this was not the case, and that with an enlarged pile the combustion of metallic wires was more rapid and brilliant, thus proving that the degree of combustion is relative to the surface of the plates (“Encyclopædia Britannica,” 1855, Vol. XXI. p. 626).

The grand experiment made conjointly by Fourcroy, Vauquelin and Seguin on the composition of water from its constituent gases was commenced May 13, 1790, and continued by them without intermission until its completion, nine days later. “The gases were fixed in a close vessel by means of electricity, and produced a nearly equal weight of water” (_Trans. Amer. Phil. Soc._, N. S., Vol. VI. p. 339, giving description of apparatus for the decomposition and recomposition of water).

Fourcroy was also one of the savants appointed in 1798 by the Academy of Sciences of Paris to examine and report upon the experiments of Galvani. The committee was composed of Guyton de Morveau, Coulomb, Vauquelin, Sabathier, Pelletan, Charles, Fourcroy and Hallé, the last named being charged with the verification of all the then recent discoveries, which were repeated with the assistance of Humboldt, who went to Paris especially for the purpose. The official report fully endorsed the praiseworthy line of researches prosecuted by both Galvani and Humboldt, and the entire series of experiments was at once repeated by many leading physicists throughout Germany.

On June 19, 1803, one of Antoine Fourcroy’s most interesting memoirs, treating of meteoric stones, was read by C. Fourcroy before the French Institute.

REFERENCES.--_Phil. Mag._, Vol. XVI. p. 299; Noad’s “Lectures,”
pp. 183, 184; Ure, “Dict. of Chem.”; also the interesting
biography embracing a list of his very numerous works and
treatises, at pp. 846–849, Vol. IX of 1855 “Encyclopædia
Britannica.” See likewise, “Royal Society Catalogue of
Scientific Papers,” Vol. II. pp. 677–682; Thomas Thomson,
“History of Royal Society,” p. 454; Wilkinson’s “Elements of
Galvanism ...” 1804, Vol. II. pp. 113, 145, 151, 152, 208, 359;
Fahie’s “History of Electric Telegraphy,” p. 194; Izarn, “Manuel
du Galv.,” 1804, s. 4, p. 167; “Journal des Savants” for Jan.
1860; P. Sue, aîné, “Hist. du Galvanisme,” Paris, 1802, Vol. II.
pp. 159–160, 241, 264. For Louis N. Vauquelin, consult “Cat. Sc.
Papers of Roy. Soc.,” Vol. VI. pp. 114–128, 761; also “Mém. des
Soc. Savantes et Litt.,” Vol. I. p. 204.

=A.D. 1801.=--Lehot (C. J.), French physicist, sends a curious and lengthy memoir, regarding the circulation of a very subtile fluid in the galvanic chain, to the Institut National, before which body it is read on the 26 Frimaire, An. IX.

To the analyzation of the above-named memoir, Wilkinson devotes more than half the tenth chapter of his “Elements of Galvanism,” calling attention to a very singular result from numerous experiments which is worthy of special mention. It is the possibility of actually distinguishing one metal from another without seeing or feeling either of them, and he says that by his arrangement of the chain, M. Lehot was able to recognize a portion of zinc from a piece of silver, at the extremity of metallic threads several yards in length.

Lehot’s contributions to the science of animal electricity are too numerous to be given here. Noad summarizes them in the translation from pp. 17, 18 of C. Matteucci’s “Traité des phénomènes ...” Paris, 1844.

He ascertained that in a recently killed animal contractions are excited by the electric current in whatever direction it may be applied, but, when the vitality of the animal has become diminished, if the current is sent in the direction of the ramifications of the nerves, contractions are produced only at the _commencement_ of the current; the reverse takes place when the current is directed contrary to the ramifications of the nerves; _i. e._ in this case the contractions only take place when the current ceases. After studying the sensation excited by the current on the organs of taste, Lehot concluded that the current which traverses a nerve in the direction of its ramifications excites a sensation when it ceases to pass, though this influence is only exerted at the _commencement_ of its passage when the nerve is traversed in a direction contrary to its ramifications. The later experiments of Carlo Francesco Bellingeri and Stefano Giovanni Marianini entirely confirm those of Lehot.

REFERENCES.--_Annales de Chimie_, Vol. XXXVIII. p. 42; _Journal
de Physique_, An. IX, Pluviose, LII. 135; Gilbert, _Annalen_,
IX. 188; P. Sue, aîné, “Hist. du Galvanisme,” Vol. II. pp. 123,
124, 129, 132, 141,142; “Encyclopedia Metropolitana,” Vol. IV
(“Electro-Magnetism,” p. 8).

=A.D. 1801.=--Wollaston (William Hyde), celebrated English chemist and natural philosopher, an associate of Sir Humphry Davy, who had taken the degree of M.D., and joined the Royal Society in 1793, but soon abandoned the practice of medicine to devote himself exclusively to scientific researches, is the first to demonstrate the identity of galvanism and frictional electricity, through a paper read before the above-named society in June 1801.

The latter communication shows that he succeeded in decomposing water as rapidly by means of mere sparks from frictional electricity as through the agency of the voltaic pile, and in a more tranquil and progressive manner than can be assured through shocks from large and powerful apparatus. He concluded that the decomposition must depend upon duly proportioning the strength of the charge to the quantity of water, and that the quantity exposed to its action at the surface of communication depends on the extent of that surface. He observes:

“Having procured a small wire of fine gold, and given to it as fine a point as I could, I inserted it into a capillary glass tube, and after having heated the tube so as to make it adhere to the point and cover it at every part, I gradually ground it down till, with a pocket lens, I could discern that the point of gold was disclosed. I coated several wires in this manner, and found that when sparks from a conductor were made to pass through water by means of a point so guarded, a spark passing to the distance of ⅛ of an inch would decompose water, when the point did not exceed ¹⁄₇₀₀ of an inch in diameter. With another point, which I estimated at ¹⁄₁₅₀₀, a succession of sparks ¹⁄₂₀ of an inch in length afforded a current of small bubbles of air. With a still finer filament of gold, the mere current of electricity, without any perceptible sparks, evolved gas from water.”

In his Bakerian lecture of Nov. 20, 1806, Sir Humphry Davy relates experiments made after the manner contrived by Wollaston, showing that the principle of action is the same in common as in voltaic electricity. Dr. Robert Hare, in a paper read before the Academy of Natural Sciences, “On the Objections to the Theories Severally of Franklin, Dufay and Ampère,” etc., says that, instead of proving the identity of galvanism with frictional electricity, the above-named experiments show that in one characteristic at least there is a discordancy, but that at the same time they possibly “indicate that ethereal may give rise to ethereo-ponderable undulations.” Noad remarks that in these ingenious experiments true electro-chemical decomposition was not effected; that is, “the law which regulates the transference and the final place of the evolved bodies had no influence.” The water was decomposed at both poles independently of each other, and the oxygen and hydrogen gases evolved at the wires are the elements of the water before existing in those places. Faraday observes:

“That the poles, or rather points, have no mutual decomposing dependence, may be shown by substituting a wire or the finger for one of them, a change which does not at all interfere with the other, though it stops all action at the charged pole. This fact may be observed by turning the machine for some time; for though bubbles will rise from the point left unaltered in quantity sufficient to cover entirely the wire used for the other communication, if they could be applied to it, yet not a single bubble will appear on that wire.”

Wollaston communicated a paper to the Royal Society (_Phil. Trans._, Vol. XCI. p. 427) showing that the oxidation of the metal is the primary cause of the electrical phenomena obtained in the voltaic pile. The oxidating power is finely shown by his eighth experiment, which he thus describes:

“Having coloured a card with a strong infusion of litmus, I passed a current of electric sparks along it, by means of two fine gold points, touching it at the distance of an inch from each other. The effect, as in other cases, depending on the smallness of the quantity of water, was most discernible when the card was nearly dry. In this state a very few turns of the machine were sufficient to occasion a redness at the positive wire, very manifest to the naked eye. The negative wire, being afterward placed on the same spot, soon restored it to its original blue colour.”

He verified in 1802 the laws of double refraction in Iceland spar announced by Huyghens, and wrote a treatise thereon which was read before the Royal Society on the 24th of June, and which contains additional evidence deduced from Dr. Wollaston’s superior mode of investigation.

He is said to have been the first to propose forming the spectrum by using a very narrow pencil of daylight instead of sunlight, and to have first made an accurate examination of the electric light. In his communication to the Philosophical Transactions for 1802 he says:

“When the object viewed is a _blue_ line of electric light, I have found the spectrum to be separated into several images; but the phenomena are somewhat different from the preceding (viz. the spectrum of the blue portion of the flame of a candle). It is, however, needless to describe minutely appearances which vary according to the brilliancy of the light, and which I cannot undertake to explain.”

During the year 1815, Wollaston made a great improvement in the construction of voltaic batteries. Having observed that the power of a battery is much increased with a corresponding economy in zinc plates, when both zinc surfaces are opposed to a surface of copper, he devised what he called an _elementary galvanic battery_. Each couple of the latter is made up only of a plate of copper doubled up around a zinc plate from which it is kept apart by strips of cork or wood, and the connecting strips of metal are attached to a wooden rod which is lowered or elevated when the battery is in or out of action. He found that a properly mounted plate of zinc, one inch square, was more than sufficient to ignite a wire of platina ¹⁄₃₀₀₀ of an inch in diameter, even when the acid is very diluted (fifty parts of water to one of sulphuric acid).

He was a very careful workman, and in order to adapt his apparatus to the popular uses, he generally endeavoured to construct them upon the most reduced scale (_dans des proportions très exigues_). He produced platinum wire so extremely fine as to be almost imperceptible to the naked eye. It was estimated that 30,000 pieces of this wire, placed side by side in contact, would not cover more than an inch; that it would take 150 pieces of this wire bound together to form a thread as thick as a filament of raw silk, and that a mile of this wire would not weigh more than a grain. It may be well to add here that the wire made with John Wennstrom’s sapphire plates, for delicate electrical apparatus, is so fine that thirty-six miles of it, properly insulated for Government use in torpedo experiments, measures only about five inches in length by three in diameter when wound upon a spool. The fibre used as carbon filaments in the incandescent lamps is scraped to an even thinness by being drawn through sapphire plates from ³⁰⁄₁₀₀₀ to ⁴⁄₁₀₀₀ of an inch in diameter.

The smallest battery that Wollaston formed of the above-described construction consisted of a thimble without its top, flattened until its opposite sides were about two-tenths of an inch asunder. The bottom part was then nearly one inch wide and the top about three-tenths, and as its length did not exceed nine-tenths of an inch, the plate of zinc to be inserted was less than three-fourths of an inch square (_Annals of Philosophy_, Vol. VI. p. 210).

We are also indebted to Dr. Wollaston for the first idea of the possibility of producing electro-magnetic rotations. Prof. Schweigger opposed the action of revolving magnetism upon the ground that if it were true, a magnet might be made to revolve around the uniting wire, but Faraday found experimentally not only that a magnet could be made to revolve round the uniting wire, but that a movable uniting wire might be made to revolve around a magnet. (See Faraday’s “Experimental Researches,” Vol, II. pp. 159–162 for “Historical Statement Respecting Electro-magnetic Rotation.”)

Wollaston was made secretary of the Royal Society in 1806, became its president in 1820 after the death of Sir Joseph Banks, and contributed in all thirty-eight memoirs to the _Philosophical Transactions_ of that Institution.

His death occurred Dec. 22, 1828, and during the following February Dr. Fitton, President of the Geological Society, concluded his annual address with the following encomium:

“It would be difficult to name a man who so well combined the qualities of an English gentleman and a philosopher, or whose life better deserves the eulogium given by the first of our orators to one of our most distinguished public characters; for it was marked by a constant wish and endeavour to be useful to mankind.”

REFERENCES.--_Phil. Mag. or Annals_, Vol. V. p. 444. See also
“The Roll Call of the Royal College of Physicians of London,”
by William Munk, M.D., Vol. II; _Edin. Phil. Jour._, Vol. X. p.
183; Gmelin’s “Chemistry,” Vol. I. p. 424; De la Rive, “Treatise
on Electricity,” pp. 444, 445; _Phil. Mag._, Vol. XXXIII. p.
488; LXIII. p. 15; James Napier, “Manual of Electro-Metallurgy,”
4th Am. ed., pp. 492, 518; Desbordeaux, in _Comptes Rendus_,
Vol. XIX. p. 273; _Le Moniteur_, No. 40 for 1806; Sue, aîné,
“Galvanisme,” Vol. II. pp. 193–195, 199, 202; Joseph Izarn,
“Manuel du Galvanisme,” p. 137; _Poggendorff_, Vol. II. p. 1362;
“Encycl. Metrop.,” Vol. IV (Galvanism), pp. 180, 181, 216, 222;
_Nicholson’s Journal_, Vol. V. p. 333; Thos. Young, “Lectures,”
London, 1807, Vol. II. p. 679; W. Sturgeon, “Scientific
Researches,” Bury, 1850, p. 29; _Quarterly Journal of Science_
for January 1821; _British Quarterly Review_ for August 1846;
“Biog. Générale,” Tome XLVI. p. 822; Highton’s “Electric
Telegraph,” p. 14; Larousse, “Dict. Universel,” Tome XV. p.
1370; “Cat. Sc. Papers ... Roy. Soc.,” Vol. I. p. 61; Vol. II.
pp. 136, 199; “Bibl. Britan.,” 1801, Vol. XVIII. p. 274; 1810,
Vol. XLIII. p. 347 (_Phil. Mag._, June 1809); Vol. I., N.S.,
1816, p. 119.

=A.D. 1802.=--Walker (Adam), English writer and inventor of several very ingenious mathematical instruments, publishes in London his enlarged edition of “A System of Familiar Philosophy,” two volumes, 8vo, in which he devotes ss. 5–9 of Lecture II. vol. i. to magnetism, and all of Lectures VII and VIII of the second volume to electricity.

We are informed, through his preface, that “the identity of fire, light, heat, caloric, phlogiston and electricity, or rather their being but modifications of one and the same principle, as well as their being the grand agents in the order of nature ... are the leading problems of the work.” In another part he tells us:

“If electricity, light and fire be but modifications of one and the same principle ... and they have their origin or foundation in the sun, it is natural to suppose, in issuing from that luminary, they proceed from him first in their purest state, or in the character of electricity; that joining the particles of our atmosphere, electricity becomes _light_, and uniting with the grosser earth, _fire_ ... that this _fire_ shall be culinary when called forth from the earth by ordinary _combustion_, and electric when called forth by _friction_. Thus have I exhibited this wonderful agent in most of the lights in which it has yet been seen; and flatter myself the reader’s deductions from these appearances will be similar to my own, viz. that electricity emanates in a perfect state from the sun and fixed stars; that its particles repel each other and fill all space; that they have an affinity to the earth and planets, but an affinity that cannot easily be gratified, because the surrounding atmospheres are in part non-conductors, being already saturated, and, of course, repellent of the electric fluid” (Lecture VIII. p. 72).

In the section devoted to “Miscellaneous Observations,” he remarks that the magnetic power may almost be said to be created by friction, rather than communicated by it; for a magnet acquires strength by giving magnetism to iron; so that, if all the magnets in the world were lost, magnetism might be revived by rubbing the end of one steel bar against the side of another.