Chapter XXXIV: Part II: for 1808 (3)

In the latter work will be found detailed his experiments with the electric spark, which he found to give a different spectrum from all other lights. Sir David Brewster says that in order to obtain a continuous line of electrical light Fraunhofer brought to within half an inch of each other two conductors, and united them by a very fine glass thread. One of the conductors was connected with an electrical machine and the other communicated with the ground. In this manner the light appeared to pass continuously along the fibre of glass, which consequently formed a fine and brilliant line of light. When this luminous line was expanded by refraction, Fraunhofer saw that, in relation to the lines of its spectrum, electric light was very different both from the light of the sun and from that of a lamp. In this spectrum he met with several lines partly very clear, and one of which, in the green space, seemed very brilliant compared with other parts of the spectrum (_Edin. Jour. of Sci._, No. XV. p. 7). He saw in the orange another line not quite so bright, which appeared to be of the same colour as that in lamplight spectra; but in measuring its angle of refraction he found that its light was much more strongly refracted, and nearly as much as the yellow rays of lamplight. In the red rays toward the extremity of the spectrum, he observed a line of very little brightness, and yet its light had the same degree of refrangibility as the clear line of lamplight, while in the rest of the spectrum he saw the other four lines sufficiently bright. In a subsequent paper read at Munich in 1823 (“Neue Modifikation des Lichtes ...” or “New Modification of Light”) and in Schumacher’s “Astronomische Abhandlungen,” Fraunhofer states that, by means of the large electrical machine in the cabinet of the Academy of Munich, he obtained a spectrum of electric light in which he recognized a great number of light lines, and that he had determined the relative place of the lightest lines as well as the ratios of their intensities.

The introduction of the electric spark for the purpose of volatilizing metals was an important step in the development of spectral analysis, but although used by both Wollaston and Fraunhofer its true value in that particular line was not realized for many years after their time.

Fraunhofer is not only celebrated as one of the founders of spectrum analysis, but he is well known also as the inventor of many important philosophical instruments, being the constructor of the great Dorpat parallactic telescope, called by Struve _the giant refractor_. It was during the year 1814 that he measured and described the innumerable dark lines of the solar spectrum known as Fraunhofer’s lines, which were first noticed by Wollaston and reported upon by the latter to the Royal Society in 1802.

REFERENCES.--M. Merz, “Das Leben und Wirken Fraunhofers,”
Landshut, 1865; Ninth “Encycl. Brit.,” Vol. IX. p. 727; “Abh.
der K. Bayer, Akad. d. Wiss.” for 1814 and 1815; Fraunhofer’s
biography in the “Memoirs of the Astronomical Society of
London,” Vol. III. p. 117; his “Determination ...” München,
1819; Whewell, “Hist. of Ind. Sci.,” 1859, Vol. II. p. 475;
_Sci. Am._, Nov. 19, 1887, p. 321; _Phil. Trans._ for 1814,
pp. 204, 205, and for 1820, p. 95; Tyndall, “Heat as a Mode of
Motion,” 1873, pp. 485, 486; article “Optics” in eighth “Encycl.
Brit.,” Vol. XVI. pp. 544, 588, 591; Sir David Brewster’s
article on “Electricity” in the “Encycl. Brit.”; “Mem. of the
Roy. Bav. Acad. of Sci.” for 1822; “On the Spectrum of the
Electric Arc,” in Jas. Dredge’s “Elec. Illum.,” Vol. I. pp. 32,
36; _Edin. Trans._, Vol. VIII for 1822; _Edin. Jour. Sci._, Vol.
XIII. pp. 101, 251; _Biblioth. Univ._, Vol. VI. p. 21, as per
Becquerel’s “Traité ...” Vol. I. p. 23; Dr. William A. Miller’s
first and third lectures before the Royal Institution in 1867;
Houzeau et Lancaster, “Bibl. Gén.,” Vol. II. p. 136; Rich. A.
Proctor, “Old and New Astronomy,” 1892, p. 787.

=A.D. 1815.=--Bohnenberger (Johann Joseph Friedrich von), 1765–1831, Professor of Mathematics and of Astronomy at the Tübingen University, constructs an extremely sensitive electrometer by suspending a single strip of gold leaf upon a wire midway between, though apart from, the insulated terminating discs of De Luc’s column.

With this contrivance he found that, however slightly the leaf was electrified, it was drawn to one of the poles according to the nature of the electricity affecting it, and he was thus enabled to observe not only the presence of the slightest electrical influence, but the kind of electricity which was present.

Noad gives, at p. 30 of his “Manual,” an illustration of the electrometer as subsequently improved by Becquerel, and states that Mr. Sturgeon describes (“Lectures on Galvanism,” 1843) a somewhat similar arrangement, the delicacy of which he states to be such that the cap (plate) being of zinc and of the size of a sixpence, the pendant leaf is caused to lean toward the negative pole by merely pressing a plate of copper, also the size of a sixpence, upon it, and when the copper is suddenly lifted up the leaf strikes. The different electrical states of the inside and outside of various articles of clothing were readily ascertained by this delicate electroscope.

M. Gottlieb Christian Bohnenberger, of Neuenberg (1732–1807), is the author of several works treating particularly of the electrical machine, the electric spark, the electric doubler, etc., published at Stuttgart between 1784 and 1798.

REFERENCES.--“La Grande Encyclopédie,” Vol. VII. p. 84; L. W.
Gilbert, _Annalen der Physik_, Vols. XXIII (for Behrend’s);
XLIX, LI (for “Beschreibung ... empfindlichen elektrometers
...”); _Annales de Chimie et de Physique_, Vol. XVI. p. 91; J.
C. Poggendorff, “Biogr.-Liter. Handwörterbuch ...” Vol. I. p.
226; _Sci. Am. Supp._, No. 519, p. 8290, for Pouillet’s remarks
upon the effectiveness of dry pile electroscopes; De la Rive,
“Treatise on Electricity,” Vol. I. pp. 54–56.

=A.D. 1815.=--Mr. B. M. Forster sends to the _Philosophical Magazine_ (Vol. XLVII. pp. 344–345) the description of an electrical instrument called “The Thunderstorm Alarum,” which can be made to show the effect produced by the passage of a charged cloud over an _atmospherical electrometer_.

He had several years before described, at p. 205 of the same publication, a method of fitting up in portable form one of De Luc’s electrical columns, respecting which latter he subsequently addressed communications, which appeared in Vols. XXXV. pp. 317, 399, 468; XXXVI. pp. 74, 317, 472; XXXVII. pp. 197, 265, also relative to one which he constructed and which ran continuously for five months.

REFERENCES.--_Phil. Mag._, Vol. IV for 1828, p. 463; eighth
“Britannica,” Vol. XXI. p. 619.

=A.D. 1815.=--Gregory (Olinthus Gilbert), LL.D., Professor of Mathematics at the Royal Military Academy, Woolwich, in his “Treatise on Mechanics,” London, 1815 (Vol. II. pp. 442–449), describes the methods of transmitting distant signals introduced by Polybius, the Marquis of Worcester, Robert Hooke, Amontons and Chappe, and alludes to an improved telegraph described in the “Gentleman’s Magazine,” as well as to the so-called nocturnal telegraph, of which an account is to be found in the _Repertory of the Arts and Manufactures_ (“Biographie Générale,” Tome XXI. p. 903).

=A.D. 1815.=--In the _Philosophical Magazine_ (Vol. XLVI. pp. 161, 259), will be found an account of the electrical experiments of M. De Nelis, of Mechlin, or Malines, in the Netherlands, with an extension of them by George J. Singer and Andrew Crosse.

These allude to many investigations made during previous years by M. De Nelis, who reported upon them to Mr. Tilloch and to M. de la Méthérie, and which show “very remarkable and permanent evidence of the expansive power of the electric charge.” Singer adds: “It is difficult to contemplate such extraordinary mechanical effects without admitting that the power by which they are produced has at least the leading characteristics of a material substance.” At p. 127, Vol. XLVIII of the _Phil. Mag._, is an account of some further electrical experiments of M. De Nelis, one of which is intended to improve the simple current with an apparatus not insulated by discs. In this communication, which bears date July 10, 1815, he discourses upon the theory of the two fluids.

=A.D. 1816.=--Coxe (John Redman), M.D., Professor of Chemistry in the University of Pennsylvania, is the second to propose a system of transmitting signals, based, like Sömmering’s (A.D. 1809), upon the discovery of Nicholson and Carlisle.

In the first series of Dr. Thos. Thomson’s _Annals of Philosophy_ for 1816 (not 1810), Vol. VII. pp. 162, 163, will be found Coxe’s letter “On the Use of Galvanism as a Telegraph,” wherein he says:

“I have contemplated this important agent as a probable means of establishing telegraphic communication with as much rapidity, and perhaps less expense, than any hitherto employed. I do not know how far experiment has determined galvanic action to be communicated by means of wires; but there is no reason to suppose it confined as to limits, certainly not as to time. Now, by means of apparatus fixed at certain distances, as telegraphic stations, by tubes for the decomposition of water, metallic salts, etc., regularly arranged, such a key might be adopted as would be requisite to communicate words, sentences or figures, from one station to another, and so on to the end of the line.... As it takes up little room, and may be fixed in private, it might in many cases of besieged towns, etc., convey useful intelligence with scarcely a chance of detection by the enemy. However fanciful in speculation, I have no doubt that, sooner or later, it will be rendered in useful practice. I have thus, my dear sir, ventured to encroach on your time with some crude ideas that may serve perhaps to elicit some useful experiments in the hands of others. When we consider what wonderful results have arisen from the first trifling experiments of the junction of a small piece of silver and zinc in so short a period, what may not be expected from the further extension of galvanic electricity? I have no doubt of its being the chief agent in the hands of nature in the mighty changes that occur around us. If metals are compound bodies, which I doubt not, will not this active principle combine their constituents in numerous places so as to explain their metallic formation; and if such constituents are in themselves aeriform, may not galvanism reasonably tend to explain the existence of metals in situations in which their specific gravities certainly do not entitle us to look for them?”

Coxe does not appear, however, to have at any time made satisfactory experiments, and his systems were considered impracticable until worked out by Alex. Bain during the year 1840.

At pp. 99–110, Vol. II of Dr. Coxe’s _Emporium of Arts and Sciences_, Philadelphia, 1812, will be found his illustrated “Description of a Revolving Telegraph,” for conveying intelligence by figures, letters, words or sentences, upon which plan, he says, he constructed a small telegraph that worked “readily and appropriately, although by no means fitted with the various pulleys, etc., to facilitate the motion of the ropes.”

REFERENCES.--For full explanation of Coxe’s systems, see L.
Turnbull, “Elect. Mag. Tel.” Highton’s “Electric Telegraph,” p.
39; _Jour. Franklin Inst._, Vol. XXI. for 1851, pp. 332, 333;
_Comptes Rendus_ for 1838, Vol. VII. pp. 593, etc.; _Sci. Am.
Supp._, Nos. 404, p. 6446, and 453, p. 7234; Alfred Vail, “The
American Electro-Magnetic Telegraph,” pp. 128, 129; Prime’s
“Life of Morse,” p. 263.

=A.D. 1816.=--In Part I of the _Philosophical Transactions_ for 1816, and at p. 14, Vol. XLVII of the _Philosophical Magazine_, will be seen an account of the observations and experiments made by Mr. John T. Todd on the _torpedo_ off the Cape of Good Hope, during the year 1812 (“Abstracts of Papers ... Roy. Soc.,” Vol. II. p. 57).

It is said that the _torpedo_ in this locality is never more than eight nor less than five inches in length, and never more than five nor less than three and a half inches in breadth. Mr. Todd found the columns of their electrical organs to be larger and less numerous in proportion than those described by Hunter, and that they appeared to be of a cylindrical form, while from a number of experiments he drew, among other conclusions, the fact that a more intimate relation exists between the nervous system and electrical organs of the _torpedo_, both as to structure and functions, than between the same and whatsoever organs of any known animal. (See Hunter at A.D. 1773.)

Reports of another series of experiments, carried on by Mr. Todd at La Rochelle during 1816, will be found in the _Phil. Trans._ for the year following as well as at p. 57, Vol. II of the “Abstracts of Papers ... of the _Phil. Trans._, 1800–1830.” The last-named investigations were made especially to determine whether the _torpedo_ possessed any voluntary power over the electrical organs, either in exciting or interrupting their action, except through the nerves of these organs.

=A.D. 1816.=--Philip--Phillip--(Wilson), English physician, publishes in the _Philosophical Transactions_ a continuation of researches made by him to establish the relations existing between the phenomena of life and voltaic electricity. Noad gives (“Manual,” pp. 341–344) an account of some of the experiments made on animals to prove the analogy existing between the galvanic energy and the nervous influence, and he alludes also to the fact of asthma having been relieved by galvanism through Dr. Philip, whose treatment had received the endorsement of Dr. Clarke Abel, of Brighton.

REFERENCES.--_Journal of Science_, Vol. IX. See also Faraday’s
“Experimental Researches,” 1791 and note; “Abstract of Papers
... _Phil. Trans._, 1800–1830,” Vol. II for 1822, p. 156.

=A.D. 1816.=--The Rev. James Bremmer, of the Shetland Islands, is rewarded by the Society of Arts for his night telegraph, the operation of which consists in the alternate exhibition and concealment of a torch in manner similar to that devised by Joachimus Fortius for Bishop Wilkins, as stated at A.D. 1641. This plan is said to have been successfully operated between the Copeland Island lighthouse and Port Patrick on the other side of the English Channel.

Particulars of the above-named night telegraph, as well as of the apparatus devised for day service, will be found in the _Trans. of the Soc. of Arts_, Vol. XXXIV. pp. 30, 213–227. The day telegraph consisted of a framework, having two circular openings, in each of which was a semicircular screen or shutter which, revolving upon an axis in the centre of the circle, was capable of assuming four different positions. This contrivance expressed an alphabet of sixteen letters, by dividing the latter into four classes of four each, and making one screen or shutter express the class, while the other indicated the number of the letter in that class.

=A.D. 1816.=--Sir Home Riggs Popham (1762–1820) British naval officer, who had been a rear-admiral in 1814, introduces his land semaphore which shows a great improvement upon all previous ones and at once replaces the Murray apparatus heretofore used by the English Admiralty (see A.D. 1795). It consists only of two arms placed upon the same hollow hexagonal mast, and movable upon separate pivots, each of which can be made to assume six different positions, giving together forty-eight different signals. It is fully described and illustrated at pp. 30, 167–177, Vol. XXXIV of the _Trans. of the Soc. of Arts_, and also appears in the “Telegraph” article, Vol. II of the “Encycl. of Useful Arts,” as well as at p. 149, Vol. XXIV of the “Penny Encycl.,” at pp. 67, 68, Vol. VIII of the (“Arts and Sciences”) “English Encycl.,” and in the “Telegraph” article by Sir John Barrow, one of the secretaries to the Admiralty, in the seventh “Britannica.”

In this same year (1816), Sir Home Popham also introduced a ship semaphore, which latter, as well as other similar devices of his construction, is to be found in the several publications already mentioned (the “Navy” article of the “Britannica” and pp. xii, xiii of Ronalds’ “Catalogue”).

=A.D. 1816.=--Ronalds (Francis), English experimentalist (1788–1873)--F.R.S., 1844, knighted 1870--whose serious attention to the development of electrical science appears to date from his meeting with M. De Luc in 1814, constructs at Hammersmith his telegraph which is the type of all dial instruments and which first presents the employment of two synchronous movements at the two stations. The telegraph is fully described and illustrated in the “Description of an Electrical Telegraph and of Some Other Electrical Apparatus,” 8vo, 83 pages, which Mr. Ronalds issued in pamphlet form, London, 1823, and which is said to be the first work published on electric telegraphy. Copious extracts from this are to be found at pp. viii-xi of the Ronalds “Catalogue,” and at pp. 129, 135–145, of Fahie’s “History,” the latter also containing several fine plates reproduced from the original work.

For his experimental line, Ronalds “erected two strong frames of wood at a distance of 20 yards from each other, and each containing 19 horizontal bars; to each bar he attached 37 hooks, and to the hooks were applied as many silken cords, which supported a small iron wire (by these means well insulated), which (making its inflections at the points of support) composed in one continuous length a distance of rather more than eight miles.” After making many experiments with this overhead line, he thus laid one underground:

“A trench was dug in the garden 525 feet in length, and four feet deep. In this was laid a trough of wood two inches square, well lined on the inside and out with pitch, and within this trough thick glass tubes were placed, through which the wire ran.”

His biographer, Mr. Frost, adds:

“In order to prevent the tubes from breaking by the variation of temperature, each length was laid a short distance from the next length, and the joint made with soft wax. The trough was then covered with pieces of wood, screwed upon it whilst the pitch was hot. They were also well covered with pitch, and the earth then thrown into the trench again.”

Mr. Edward Highton, at p. 40 of his work, the “Electric Telegraph,” 1852, says:

“Ronalds employed an ordinary electric machine and the pith-ball electrometer in the following manner. He placed two clocks at two stations; these two clocks had upon the second hand arbor a dial with twenty letters on it; a screen was placed in front of each of these dials, and an orifice was cut in each screen, so that only one letter at a time could be seen on the revolving dial. The clocks were made to go isochronously; and as the dials moved round the same letter always appeared through the orifices of each of these screens. The pith-ball electrometers were hung in front of the dials. The attention of the observer was called through the agency of an inflammable air gun fired by an electric spark.”

Realizing the value of his invention, Ronalds strove to bring it before the English Government, but was met (Aug. 5, 1816), with much the same encouragement we have seen vouchsafed Sharpe (A.D. 1813), and Wedgwood (A.D. 1814), viz. “Telegraphs of any kind are now wholly unnecessary and no other than the one now in use will be adopted.” The one alluded to was the semaphore line between London and Portsmouth, originally of the Chappe pattern and improved upon by Charles W. Pasley and Rear Admiral Popham.

Alluding to Mr. (afterward Sir) John Barrow’s letter in a note at p. 24 of his work Ronalds says:

“... Should they again become necessary, however, perhaps electricity and electricians may be indulged by his Lordship and Mr. Barrow with an opportunity of proving what they are capable of in this way.”

He was so disappointed that he not long after announced his “taking leave of a science which once afforded him a favourite source of amusement,” and that he was “compelled to bid a cordial adieu to electricity.” Fortunately for the scientific world, however, he afterward gave his attention again to electrical matters as is evidenced by many important papers contained in the publications noted below.

In Ronalds’ afore-named work the phenomenon of retardation of signals in buried wires is clearly foreseen and described, although Zetzsche endeavours to combat this assertion at p. 38 of his “Geschichte der Elektrischen Telegraphie,” Berlin, 1867. Speaking of the apprehended difficulty of keeping the wire charged with electricity, Ronalds suggests that when not at work “the machine be still kept in gentle motion to supply the loss of electricity by default of insulation; which default, perhaps, could not be avoided, because (be the atmosphere ever so dry, and the glass insulators ever so perfect), conductors are, I believe, robbed of their electricity by the same three processes by which Sir Humphry Davy and Mr. Leslie say that bodies are robbed of their sensible heat, viz. by radiation, by conduction, and by the motion of the particles of air.” He also gives descriptions of an improved electrical machine (eighth “Britannica,” Vol. VIII. p. 536; _Sci. Am. Supp._, No. 647, p. 10326; Noad’s “Manual,” p. 69), of a new method of electrical insulation and of some experiments on Vesuvius (_Quarterly Jour. of Sci._, Vols. II. p. 249; XIV. pp. 332–334), of a new electrograph for registering the charge of atmospheric electricity, of a pendulum doubler (_Edin. Phil. Jour._, Vol. IX, 1823, pp. 323–325) and of an attempt to apply M. De Luc’s electric column to the measurement of time. His other contributions relative to the dry pile are to be found in the _Phil. Mag._, Vols. XLIII. p. 414, and XLV. p. 466.

REFERENCES.--“Biog. Mem. of Sir Francis Ronalds, F.R.S.,” by
Alfred J. Frost, in Ronalds’ “Catalogue”; “Mem. of Dist. Men of
Science,” by William Walker; Ronalds’ “Corres. and Memoir.,”
in 1848–1849, to 1853, to April 17, 1855, to June 5, 1856, to
Sept. 2, 1862, and in 1866–1870; Ronalds’ “Walk Through ... Exh.
of 1855”; _Illustrated London News_ of April 30, 1870; eighth
“Britannica,” Vol. VIII. pp. 622, 627, for Ronalds’ improved
electrometers and his telegraph; _Nature_, London, Nov. 23,
1871, Vol. V. p. 59; _Journal of the Telegraph_, March 15,
1875, Vol. VIII. p. 82, reporting the inaugural address of Mr.
Latimer Clark before the English Society of Tel. Engineers;
_Comptes Rendus_ for 1838, Vol. VII. pp. 593, etc.; _Sci. Am.
Supp._, No. 384, pp. 6, 127; No. 547, p. 8735, and No. 659,
p. 10521, for his Telegraph; “Bombay Mag. Observatory,” 1850;
_Fortschrift des Phys._, Vol. III. p. 586, and Buys-Ballot
“Meteor. Preisfrage,” 1847, for Ronalds’ apparatus to measure
atmospheric electricity; _Phil. Mag._, Vols. XLIV. p. 442;
XLV. p. 261; XLVI. p. 203; and third series, Vols. XXVIII for
1846; XXXI. p. 191; British Ass. Reports for 1845, 1846, and
Reports concerning the Kew Observatory for 1845, 1850, 1852;
_Phil. Trans._ for 1847, Moigno’s _Le Cosmos_, Vol. XIII; L. Von
Forster, “All. Bauzeitung” for 1848, p. 238; Noad’s “Manual,”
pp. 184, 185, 748; Knight’s “Mechanical Dictionary,” Vol. I. p.
708; Turnbull’s “Electro-magnetic Telegraph,” p. 22; _Annals
of Electricity_, Vol. III. p. 449; “English Cyclop.” (Arts and
Sci.), Vol. VIII. pp. 71, 72; _Jour. Soc. Teleg. Eng._, 1879,