Chapter VI: Part 6

Wolf and other mathematicians are of opinion that the most advantageous form of a speaking-trumpet would be found with more certainty by experience than by theory. It may then be asked, whether any one ever caused such an instrument to be made from these descriptions. Kircher, who attempted things much more improbable, says he never tried it. Duhamel however relates that a Frenchman tried it, and discovered the real instrument[231]; but this information is of little weight, as it is much to be doubted that this Frenchman caused it to be made sufficiently exact according to the ancient description. I am as little acquainted with Bettini as Morhof; but I suspect that Duhamel meant Mar. Bettini, who, without making the smallest mention of Alexander’s horn, proposes only a tube, the one end of which should be applied to the mouth of a person who speaks, and the other to the ear of one who is dull of hearing[232]. This was rather an ear-trumpet than a speaking-trumpet, and it is certain that the former was invented before the latter.

What we read in Porta, and what many think alludes to a speaking-trumpet, alludes evidently to an ear-trumpet only. That author infers, very justly, from the form of the ear, and particularly from that of the ears of those animals which are quick of hearing, that to hear at a distance one must apply to the ear a kind of wide funnel, as people to strengthen the sight use spectacles[233]. He asserts also, with equal truth, that one, through a long tube, can convey a whisper to the ear of another person at a very great distance[234]; an experiment which he himself made at the distance of two hundred paces. Schwenter, who wrote before the speaking-trumpet was known, proposes, from the hint of Porta, an ear-trumpet, one end of which should be applied to the ear[235].

Sir Samuel Morland, an Englishman, and the jesuit Kircher, have in later times contended respecting the invention of the speaking-trumpet. The former, in 1671, published a particular description of one, after he had made many experiments upon it the year preceding. This instrument, shaped like a wide-mouthed trumpet, he caused first to be constructed of glass, and afterwards of copper, with various alterations, and performed several experiments with it in presence of the king (Charles II.), prince Rupert, and other persons, who were astonished at its effects[236].

As an account of this discovery was soon spread all over Europe, Kircher asserted that he had constructed speaking-trumpets before Sir Samuel Morland, and supported his assertion by referring to his former writings, and by the testimony of other authors. I shall first take notice of the former. His Ars Magna Lucis et Umbræ was first printed in 1643. I at least conclude so, because, in the preface to his Phonurgia, printed in 1673, he says that work had been published thirty years before. The second edition is of 1671, in which I find only the already-quoted passage respecting Alexander’s horn, and the figure of a tube, which, like that proposed by Bettini, should be applied to the ear of a person who hears, and to the mouth of the speaker. The Musurgia, printed in 1650, contains better grounds for supporting the assertion of Kircher. In the second part he describes how a funnel can be placed in a building in such a manner, that a person in an apartment where the narrow end is introduced can hear what is spoken without the building, or in another apartment, where the wide end may be. To this description a figure is added, and the author acknowledges he was led to that idea by the construction of a well-known building of Dionysius[237]. He does not however say expressly that he had ever tried the experiment; but in the last page of the preface to the Phonurgia, he pretends that so early as the year 1649 he had caused such a machine to be fixed up in the Jesuits’ college. But, supposing this to be true, it can only be said that he then approached very near to the invention of the speaking-trumpet, by an instrument, which, in reality, however, was calculated to strengthen the hearing, and not the voice; and therefore only the half is true of what he advanced in his preface in 1673, that twenty years before he had described in his Musurgia the trumpet invented in England.

In the Phonurgia, however, written after Morland’s publication was everywhere known, Kircher certainly treats of the speaking-trumpet, and says that, from the similarity of the progress of sound to that of the rays of light, he was led to the idea of conveying the former, in the same manner as the latter, to a great distance, by means of an instrument. For this purpose, about twenty-four years before, he had caused to be constructed, in the Jesuits’ college at Rome, an ear-trumpet, through which the porter could communicate anything he had to say to him when he was in his apartment in the upper story. This apparatus attracted the notice of many strangers, who were astonished at its effect. He here represents it as a proper speaking-trumpet, and adds, that it excited much surprise, on account of the uncommon strength which it gave to the voice. For this reason he was very desirous of trying to what distance words could be distinctly conveyed by such a tube; and an opportunity occurred of doing this the same year that he wrote his Phonurgia. From a convent, situated on the top of a mountain, he assembled twelve hundred persons to divine service, at the distance of from two to five Italian miles, and read the Litany through it. Soon after, the emperor caused a tube to be made according to Kircher’s description, by which, without elevating the voice, he could be understood from Ebersdorf to Neugebeu. But though Kircher came so near to the invention of the speaking-trumpet, it does not appear certain by his works that he attempted or constructed it before Sir Samuel Morland. I shall now examine the evidences he adduces in his favour.

The most important of these is Schott, because he published his Magia Naturalis[238] in 1657, before the invention of Sir Samuel Morland. All that is to be found in this work, however, relates alone to the ear-trumpet, a figure of which is added from the Musurgia; but we learn, with certainty, that Kircher then had the before-mentioned funnel or tube in his apartment. It is also not improbable that he had tried to answer the porter from his apartment, and that he had thereby remarked that the voice was strengthened; for it is not proved by Schott that he at that time was acquainted with and had in his possession a portable speaking-trumpet.

Another author by whom Kircher endeavours to support his claim is Harsdorfer; who, however, speaks only of tubes to be closely applied to the mouth and to the ear, and who refers to the Musurgia, without mentioning the real speaking-trumpet, though the second part of his Mathematical Recreations was first printed in 1677, and the third in 1692. Besides these testimonies, Kircher quotes also Eschinard concerning sound[239]. With that work I am not acquainted; but as the information it contains is taken from the Musurgia, it is of as little importance as that of Derham[240], who refuses the invention to his countryman, and gives it to Kircher. When I unite all the evidence in favour of Kircher, it appears to be certain that he made known and employed the ear-trumpet earlier than the portable speaking-trumpet; that he, however, approached very near to the invention of the latter, but did not cause one to be constructed before Sir Samuel Morland, to whom the honour belongs of having first brought it to that state as to be of real use. Such, at least, is the manner in which this dispute is decided by the Jesuit De Lanis[241].

When Morland’s invention was made known in France, it was pretended that Salar, an Augustine monk, had seven or eight years before caused such tubes or trumpets to be made, in order to strengthen the voice of a weak bass-singer; but he himself acknowledges that he never had an idea of speaking with them at a distance[242].

This instrument was soon made for sale at Nuremberg in Germany, particularly by that well-known artist Grundler, mentioned by Becher, who imagined that two persons, by means of a speaking-trumpet and an ear-trumpet, could converse together at a great distance, without any one in the neighbourhood, or in the intermediate space, hearing what they said.

Of those who employed their ingenuity in improving this instrument I shall mention the following. Cassegrain, known on account of his optical instruments, published some hints for that purpose in 1672[243]; as did Sturm[244], Conyers[245], Hase and others afterwards. The last who investigated the theory of the speaking-trumpet was Lambert[246]; according to whose ideas the figure of a shortened cone, if not the best, is at least as good as any other that might be employed.

[It would appear, however, from the experiments of Hassenfratz (Journ. de Phys., t. xxvi.) that neither the shape of the instrument nor the material of which it is composed is of much consequence. He ascertained the power of the trumpet by fixing a small watch in the mouth-piece, and observing the distance at which the beats ceased to be audible, and thus found that the effects were precisely the same with a trumpet of tinned iron, whether used in its naked form, or tightly bound round with linen to prevent vibration, or when lined with woollen cloth whereby reflexion was entirely prevented; he also found that the range of a cylindrical trumpet was as great as that of a conical one.

Leslie supposes the effect of the trumpet to be owing to the more condensed and vigorous impulsion given to the air from its lateral flow being checked. He observes, “that the tube, by its length and narrowness, detains the efflux of air, and has the same effect as if it diminished the volubility of that fluid, or increased its density. The organs of articulation strike with concentrated force, and the pulses, so vigorously thus excited, are, from the reflected form of the aperture, finally enabled to escape and to spread themselves along the atmosphere[247].”]

FOOTNOTES

[224] Goguet. i. p. 326.

[225] Plin. lib. xvi. c. 38, p. 32.

[226] Septalii Comm. in Aristotelis Problem. Lugd. 1632, fol. p. 206. There is also a passage to the same purpose in Seneca, Epist. 108.

[227] See Anciennes Relations des Indes et de la Chine, de deux voyageurs Mahometans, qui y allèrent dans le neuvième siècle. Par Renaudot. Paris, 1718, 8vo, p. 25.

[228] Ars magna lucis et umbræ. Amst. 1671, fol. p. 102. Kircher repeats this account with some new circumstances in his Phonurgia, p. 132.

[229] Morhofii Diss. de vitro per vocis sonum rupto, in Dissertationibus Academicis. Hamburgi 1669, 4to, p. 381.

[230] Morhof quotes the following passage:--“With this brazen horn, constructed with wonderful art, Alexander the Great called together his army at the distance of sixty miles. On account of its inestimable workmanship and monstrous size, it was under the management of sixty men. Many kinds of sonorous metals were combined in the composition of it.”

[231] “Among many things which the celebrated D’Alance caused to be made for this purpose, the trumpet ascribed to Alexander, and with which he called together his army, ought not to be omitted. As the figure of it was represented in an old manuscript in the Vatican library, and had been described by Bettini, that learned man was desirous of trying whether it could be proved by experience, and the attempt succeeded; for that kind of trumpet, if it does not excel, seems undoubtedly to equal the other instruments constructed for that end.”

[232] Bettini Apiaria univ. Philosophiæ Mathemat. Bonon. 1642, fol. p. 38.

[233] Magia Natural. lib. xx. c. 5.

[234] “To communicate anything to one’s friends by means of a tube. This can be done with a tube made of earthenware, though one of lead is better, or of any other substance, but very close, that the voice may not be weakened; for whatever you speak at the one end, the words issue perfect and entire as from the mouth of the speaker, and are conveyed to the ears of the other, which, in my opinion, may be done for some miles. The voice, neither broken nor dispersed, is carried entire to the greatest distance. We tried it at the distance of two hundred paces, not having convenience for a greater, and the words were heard as clearly and distinctly as if they had come from the mouth of the speaker.”--Lib. xvi. c. 12.

[235] Mathematische Erquickstunden, i. p. 243.

[236] An Account of the Speaking-trumpet, as it hath been contrived and published by Sir Samuel Morland, knight and baronet, together with its use both at sea and land. London, 1671. An extract from it may be seen in the Phil. Trans., No. 78, p. 3056.

[237] Among the antiquities of Syracuse in Sicily, one beholds with wonder chambers and galleries which are hewn out in the solid rock, and particularly a grotto, from which arises a winding passage, that becomes upwards still narrower. Ancient tradition says that this was a prison, which the celebrated tyrant Dionysius caused to be built for state prisoners, that in an apartment of his palace, which stood over the narrow end of the passage, he might hear everything the prisoners said, or what plots they formed against him. This grotto therefore is called _Orechio di Dionysio_, or _la grotta della favella_; _auris Dionysii_, the ear of Dionysius. Many travellers and others formerly imagined that this passage was an ingenious imitation of that part of the human ear called the helix, which was first remarked by Alcmaon the Pythagorean. This is the account given by Kircher, who was there in the year 1638. See his Phonurgia (published 1673), p. 82, where there is a figure of it. In later times, however, this grotto has been examined with more skill and acuteness by people less subject to prejudice, and since that period the supposed wonder has been lessened. The rock consists of limestone, at least I conclude so from what is said by Brydone, who found it everywhere full of cracks and fissures. The stones of which Syracuse was built were hewn from the rock; and hence have been formed these chambers or openings, like those found in the neighbourhood of other ancient and modern cities, such as Rome, Naples, and Maestricht. Many of these, in the course of time, have been employed as prisons, or used as burying-vaults. The above-mentioned passage, which has excited so much wonder, is not properly spiral, and is of such a figure that it may have been produced either by accident or through the whim of the workmen employed to hew out the stones. The double echo which Kircher assures us he heard in the grotto was not remarked by Schott, who was there in 1646, as he expressly says, in opposition to his brother jesuit, in his Magia Naturalis. In the accounts still remaining of Dionysius we find mention of an astonishing prison, which is well described by Cicero in his fifth oration against Verres: “You have all heard of,” says he, “and most of you know the prison (lautumias) of Syracuse. It is an immense and magnificent work, executed by kings and tyrants; the whole is sunk to a wonderful depth in the rock, and has been entirely cut out by the labour of many hands. No place so secured against an escape; no place so enclosed on all sides; no place so safe for confining prisoners can be either planned out or constructed.” But it cannot be proved, and according to D’Orville’s opinion it is improbable, that this grotto was the work of that tyrant, who, as Plutarch tells us in his Life of Dion, employed very different means to learn the intention of dangerous persons. “The common people attacked the tyrant’s friends, and seized those whom they called his emissaries (προσαγώγιδας), worthless men, detested by the gods. These went about the city, mixed with the citizens, and, prying into everything, gave an account to the tyrant of what they thought and what expressions they made use of.” It was merely for its strength, and the labour employed in building it, and not on account of its ingenious construction, that the ancients admired the prison of the tyrant. At present the upper end of the winding passage is closed up; and it is so narrow, that some years ago the captain of an English vessel found great difficulty to clamber up it. It cannot, however, be denied that this grotto may have been used for the service ascribed to it; and I can readily believe that it may have led Kircher to the invention of the ear-trumpet. See the Travels of P. de la Valle, Ray, and Brydone; Delle antiche Siracuse, da G. Bonanni, &c., 2 vols. fol. Palermo 1717. Dan. Bartolo del suono e de’ tremori harmonici, Bonon. 1680, who examined this grotto as a naturalist. D’Orville, Sicula. Amst. 1764, pp. 182, 194.

[238] This machine was invented by Kircher, in imitation of the ear of Dionysius; nor is it a vain and empty speculation, for the machine produces an infallible effect. Kircher caused to be made at Rome, of tin plate, a very large and straight tube, like a funnel, and placed it in an apartment next to his chamber, in such a manner that the large end projected into the garden of the college, and the less entered his chamber. When the porter of the college had occasion to call him to the gate, that he might not be obliged always to go up stairs, or to bawl out, he went to the broad end of the funnel, and communicated what he wished to Kircher.--Schotti Magia Universalis, ii. p. 156.

[239] Eschinardi Discursus de Sono Pneumatico, p. 10.

[240] Physico-theology.

[241] Our Kircher, in his Phonurgia, justly claims that invention, as it was several years ago exhibited by him in the Jesuits’ college at Rome, and an account of it printed. That this is true I myself was an eye-witness; though I must acknowledge that no one before the above-mentioned Englishman ever applied this speaking instrument, at least in so perfect a manner, to that use for which it was afterwards employed.--Magisterium Naturæ et Artis. Brixiæ, 1684-92, fol. ii. p. 436.

[242] Journal des Sçavans, tome iii.

[243] Ibid. p. 131.

[244] J. A. Sturm, Collegium Experimentale, ii. p. 146.

[245] Philosophical Transactions.

[246] Mémoires de l’Acad. des Sciences à Berlin, 1763, p. 97.

[247] Experimental Inquiry into the Nature, &c. of Heat, p. 225.

ANANAS.--PINE-APPLE.

To discover the excellence of the ananas required no great skill; it recommended itself so much by its taste, smell, and colour, as to attract the notice of the first Europeans who visited Brazil; and we find it praised in the earliest writers on America, who give an account of it, as well as of tobacco, maize, and other productions of the new world.

Gonçalo Hernandez de Oviedo is, as far as I know, the first person who described and delineated the ananas. This author was born at Madrid in 1478, went to America in 1513, and in 1535 was governor of St. Domingo. In the last-mentioned year his General History of America was printed at Seville. At that time three kinds were known, which in America were called _yayama_, _boniama_, and _yayagua_, but by the Spaniards _pinas_. Attempts had then been made to send the fruit to Spain by pulling it before it was ripe; but it had always become spoilt in the course of the voyage. Oviedo had tried also to send slips or young shoots to Europe, but these also died by the way. He however entertained hopes that means would be found to rear the ananas in Spain, in which maize or Turkish corn had been brought to maturity, provided it could be transported with sufficient expedition[248].

Geronimo Benzono, a Milanese, who resided in Mexico from 1541 to 1555, caused, on his return, his History of the New World to be printed, for the first time, at Venice in 1568. In this work he highly extols the pinas, and says he believes that no fruit on the earth can be more pleasant; sick persons, who loathed all other food, might relish it.

After him, Andrew Thevet, a French monk, who was in Brazil from 1555 to 1556, described and delineated this plant under the name of _nanas_. The art of preserving the fruit with sugar was at that time known[249].

John de Lery, who went to Brazil in 1557 as chaplain to a Huguenot colony, in the account of his voyage first used the word _ananas_, which probably took its rise from the _nanas_ of Thevet[250].

In the middle of the sixteenth century Franc. Hernandes, a naturalist, undertook an expensive, and almost useless voyage to Mexico. It cost Philip II. king of Spain 60,000 ducats, and the observations he collected, for which, at the time Acosta was in America, 1200 figures were ready, were never completely printed; and in what are printed one can scarcely distinguish those of the original author from the additions of strangers. He has, however, given a somewhat better figure of the ananas, which he calls _matzatli_ or _pinea Indica_[251].

Christopher Acosto, in his Treatise of the drugs and medicines of the East Indies, printed in 1578, calls this plant the ananas. He says it was brought from Santa Cruz to the West Indies, and that it was afterwards transplanted to the East Indies and China, where it was at that time common. The latter part of this account is confirmed by J. Hugo de Linschotten, who was in the East Indies from 1594 to 1595[252].

Attempts were very early made, as Oviedo assures us, to transplant the ananas into Europe; and as in the beginning of the seventeenth century it was reckoned among the marks of royal magnificence to have orange-trees in expensive hot-houses, it was hoped that this fruit could be brought to maturity also in the artificial climate of these buildings. These attempts, however, were everywhere unsuccessful; no fruit was produced, or it did not ripen, because, perhaps, this favourite exotic was treated with too much care. It is not certainly known who in Europe first had the pleasure of seeing ananas ripen in his garden; but it appears that several enjoyed that satisfaction at the same time in the beginning of the last century.

The German gardens in which the ananas was first brought to maturity appear to have been the following. First, that of Baron de Munchausen, at Schwobber, not far from Hameln, which on account of the botanical knowledge of its proprietor, and the abundance of plants it contains, is well-known to all those who are fond of botany. In the beginning of the last century it belonged to Otto de Munchausen, who, perhaps, was the first person who erected large buildings for the express purpose of raising that fruit, and who had the noble satisfaction of making known their advantageous construction. With this view he sent a description and plan of his ananas-houses to J. Christopher Volkamer, a merchant of Nuremberg, who inserted them in his continuation of the Nuremberg Hesperides, printed there in 1714, and by these means rendered the attainment of this fruit common. This Baron de Munchausen is the same who has been celebrated by Leibnitz: “All the travellers in the world,” says that great man, “could not have given us, by their relations, what we are indebted for to a gentleman of this country, who cultivates with success the ananas, three leagues from Hanover, almost on the banks of the Weser, and who has found out the method of multiplying them, so that we may, perhaps, have them one day as plentiful, of our own growth, as the Portuguese oranges, though there will, in all appearance, be some deficiency in the taste[253].” As the Baron Munchausen’s garden at Schwobber was in the absence of the proprietor, as Volkamer says, under the care of J. F. Berner, canon of the cathedral of St. Boniface, he probably may have had some share in rendering this service to horticulture.

This fruit was produced also in the garden of Dr. Volkamer at Nuremberg, and in that of Dr. F. Kaltschmid at Breslau, almost about the same time. The latter was so fortunate as to bring it to maturity so early as 1702, and he sent some of it then for the first time to the imperial court. At Frankfort on the Maine it was first produced in 1702[254]; and at Cassel in 1715, by the skill of Wurstorfs, the head gardener.

Holland procured the first ripe ananas from the garden of De la Court, whom Miller calls Le Cour, in the neighbourhood of Leyden. As a great many plants were sold out of this garden to foreigners, and as the English had theirs first from it, many are of opinion that Europe is indebted for the first possession of this fruit to De la Court, and his gardener William de Vinck[255].

I shall here take occasion to mention a circumstance which belongs also to the history of gardening. Before the cultivation of the ananas was introduced, the Dutch had begun to employ tanner’s bark for making forcing-beds. From them the English learned this improvement, and the first forcing-beds in England were made at Blackheath in Kent, in 1688, and employed for rearing orange-trees; but about the year 1719, much later than in Holland, ananas became more common, and forcing-beds were in much greater use[256].

This plant, the history of which I have given, received from Plumier[257], who first distinguished its characters, the name of _Bromelia_[258], after the Swedish naturalist, whose remembrance deserves to be here revived. Olof Bromelius was born in 1639, at Oerebro, where his father carried on trade. He studied physic at Upsal, disputed there in 1667 de Pleuritide, and in 1668 taught botany at Stockholm. In 1672 he was physician to the embassy to England, and afterwards to that to Holland, where, in 1673, he received the degree of doctor at Leyden, and wrote a dissertation De Lumbricis. On his return to his native country, in 1674, he became a member of the college of physicians at Stockholm; but in 1691 he was city physician to Gottenburg, and provincial physician in Elsburg and Bahuslan, in which situation he died in the year 1705. His botanical writings are Lupologia, and Chloris Gothica[259]. His son, Magnus von Bromel, is the author of Lithographia Suecana.

[Within the few last years, large numbers of pine-apples have been imported into this country from the Bahamas, where they are grown as turnips are grown in our fields. They are sold comparatively speaking at an extremely moderate price, and those that have become somewhat spoilt by the long carriage are hawked about the streets of London at a halfpenny or penny per slice. They are however vastly inferior in flavour to the pines cultivated in our hot-houses, but it is to be expected, from the considerable demand, that greater care will be bestowed on their cultivation, and the markets of London be regularly supplied with a much improved kind.]

FOOTNOTES

[248] La Historia General de las Indias. Sevilla, 1535, fol. lib. xvii. c. 13. [An earlier notice of the pine-apple had been given by Andræa Navagero in his letter to Rannusio, dated from Seville, May 12, 1526. He says, “I have also seen a most beautiful fruit, the name of which I do not recollect: I have eaten of it, for it was imported fresh. It has the taste of the quince, together with that of the peach, with some resemblance also of the melon: it is fragrant, and is truly of most delicious flavour.”--Lettere di xiii Huomini Illustri.]

[249] Les Singularitez de la France Antarctique, autrement nommée Amerique. Par André Thevet. Anvers, 1558.

[250] Voyage faict en la terre du Brésil, autrement dite Amerique. Par J. de Lery. Genève, 1580, 8vo, p. 188.

[251] Rerum Med. novæ Hispaniæ Thesaurus. Rome, 1651. fol.

[252] The accounts given by Acosta and Linschotten may be seen in Bauhini Histor. Plantarum, iii. p. 95. Kircher in his China Illustrata says, “That fruit which the Americans and people of the East Indies, among whom it is common, call the ananas, and which grows also in great abundance in the provinces of Quantung, Chiamsi, and Fokien, is supposed to have been brought from Peru to China.”

[253] See Leibnitz, Nouveaux Essais sur l’Entendement Humain (Œuv. Phil.), p. 256, Amst. 1765, 4to.

[254] Lersner, Chronik, ii. p. 824.

[255] Miller’s Gardener’s Dictionary, i. p. 132. Lueder, Wartung der Küchengewächse. Lubeck, 1780, 8vo, p. 248.

[256] Miller, ii. p. 824. Lueder, p. 39. That putrid bark forms an excellent manure, had been before remarked by Lauremberg, in Horticultura, p. 52.

[257] Nova Plantarum Americanarum Genera. Parisiis 1708, 4to, p. 46.

[258] [The plants producing the pine-apple have been separated by Prof. Lindley under the name _Ananassa_ from the allied genus _Bromelia_, after which the Natural Order BROMELIACEÆ takes its name.]

[259] Halleri Bibl. Botan. i. p. 640.

SYMPATHETIC INK.

If we give this name to any fluid, which when written with, will remain invisible till after a certain operation, such liquids were known in very early periods. Among the methods, with which Ovid teaches young women to deceive their guardians, when they write to their lovers[260], he mentions that of writing with new milk, and of making the writing legible by coal-dust or soot. Ausonius proposes the same means to Paulinus[261]; but his commentators seem not to have fully understood his meaning; for _favilla_ is not to be explained by _favilla non modice calida_, as Vinetus has explained it, but by _fuligo_. That word is often employed by the poets in the same sense. As a proof of it, Columella, speaking of the method, not altogether ineffectual, and even still used, of preserving plants from insects by soot, calls it _nigra favilla_; and afterwards, when mentioning the same method, free from poetical fetters, he says _fuliginem quæ supra focos tectis inhæret_[262]. It may be easily perceived, that instead of milk any other colourless and glutinous juice might be employed, as it would equally hold fast the black powder strewed over it. Pliny, therefore, recommends the milky sap of certain plants for the like purpose[263].

There are several metallic solutions perfectly colourless, or, at least, without any strong tint, which being used for writing, the letters will not appear until the paper be washed over with another colourless solution, or exposed to the vapour of it; but among all these there is none which excites more astonishment, than that which consists of a solution of lead in acetic acid, and which by sulphuretted hydrogen gas becomes black, even at a considerable distance. This ink, which may be employed by conjurers, proves the subtlety of this gas, and the porosity of bodies; as the change or colouring takes place, even when the writing is placed on the other side of a thin wall.

This effect presented itself perhaps accidentally to some chemist; but the discovery is not of great antiquity. Wecker, who compiled his book De Secretis from Porta, Cardan, and several old writers, and printed it for the first time in 1582, and gave a third edition in 1592, must have been unacquainted with it; else he certainly would not have omitted it in the fourteenth book, where he mentions all the methods of secret writing. Neither would it have been unnoticed by Caneparius, whose book De Atramentis was printed at Venice, for the first time, in 1619.

The first person who, as far as I have been able to learn, gave a receipt for preparing this ink, was Peter Borel, in Historiarum et Observationum Medico-physic. Centuriæ quatuor. In this work, which was printed for the first time in 1653, and a second time in 1657, at Paris, and of which there were several editions afterwards, the author calls it a magnetic water, which acts at a distance[264]. After the occult qualities of the schoolmen were exploded, it was customary to ascribe phænomena, the causes of which were unknown, and particularly those the causes of which seemed to operate without any visible agency, to magnetic effluvia; as the tourmaline was at first considered to be a kind of magnet. Others concealed their ignorance under what they called sympathy, and in latter times attraction and electricity have been employed for the like purpose. Borel, who made it his business to collect new observations that were kept secret, learned the method of preparing this magnetic water from an ingenious apothecary of Montpelier, and in return taught him some other secrets. Otto Tachen, a German chemist[265], afterwards thought of the same experiment, which he explains much better, without the assistance of magnetism or sympathy. The receipt for making these liquids, under the name of sympathetic ink, I find first given by Le Mort[266], and that name has been still retained[267].

Another remarkable kind of sympathetic ink is that prepared from cobalt, the writing of which disappears in the cold, but appears again of a beautiful green colour, as often as one chooses, after being exposed to a moderate degree of heat.

The invention of this ink is generally ascribed to a Frenchman named Hellot. He was, indeed, the first person who, after trying experiments with it, made it publicly known, but he was not the inventor; and he himself acknowledges that a German artist of Stolberg first showed him a reddish salt, which, when exposed to heat, became blue, and which he assured him was made out of Schneeberg cobalt, with aqua regia[268]. This account induced Hellot to prepare salts and ink from various minerals impregnated with cobalt; but A. Gesner proved, long after, that this ink is produced by cobalt only, and not by marcasite[269].

When Hellot’s experiments were made known in Germany, it was affirmed that Professor H. F. Teichmeyer, at Jena, had prepared the same ink six years before, and shown it to his scholars, in the course of his lectures, under the name of sympathetic ink[270]. It appears, however, that it was invented, even before Teichmeyer, in the beginning of the last century by a German lady. This is confirmed by Pot, who says that the authoress of a book printed in 1705, which he quotes under the unintelligible title of D. J. W. in clave, had given a proper receipt for preparing the above-mentioned red salt, and the ink produced by it[271]. If it be true that Theophrastus Paracelsus, by means of this invention, could represent a garden in winter, it must be undoubtedly older[272].

[In consequence of the progress of modern chemistry and the discovery of a vast number of new chemical compounds, sympathetic inks may be made in an almost endless number and variety. The principal may be classed in the following manner:--1, _such as when dried upon paper being invisible, on moistening with another liquid become again evident_: of this kind there are a vast number; among which we may mention a solution of a soluble salt of lead, or bismuth, for writing, and a solution of sulphuretted hydrogen for washing over; the writing then appears black; or green vitriol for writing and prussiate of potash for washing over, when the writing becomes blue[273]; 2, _such as are rendered evident by being sifted over with some powder_, as the milk with soot described above; 3, _those which become visible by heat_, such as characters in dilute sulphuric acid, lemon-juice, solutions of the nitrate and chloride of cobalt, and of chloride of copper; the two former become black or brown, the latter are rendered green, the colouring disappearing subsequently when allowed to cool in a moist place. Amusing pictures are sometimes made with these sympathetic inks, particularly those composed of cobalt; for if a landscape be drawn to represent winter, the vegetation being covered with a solution of cobalt, on holding the paper to the fire, all those portions covered with the solution appear of a bright green, and thus completely change the character of the scene.]

FOOTNOTES

[260] De Arte Amandi, lib. iii. v. 629.

[261] Ausonii Epist. xxiii. v. 21. The poet afterwards teaches other methods of secret writing, and Gellius, lib. xvii. cap. 9, mentions the like.

[262] Colum. De Re Rust. x. 354. and xi. 3, 60.

[263] Plin. lib. xxvi. cap. 8. p. 400.

[264] The sixth observation of the second century is as follows: _Magnetic waters which act at a distance_. An astonishing effect, indeed, is produced by the contest of the following waters, which are thus made. Let quick-lime be quenched in common water, and while quenching, let some orpiment be added to it (this however ought to be done by placing warm ashes under it for a whole day), and let the liquor be filtered, and preserved in a glass bottle well corked. Then boil litharge of gold well pounded, for half an hour with vinegar in a brass vessel, and filter the whole through paper, and preserve it also in a bottle closely corked. If you write any thing with this last water with a clean pen, the writing will be invisible when dry; but if it be washed over with the first water it will become instantly black. In this, however, there is nothing astonishing; but this is wonderful, that though sheets of paper without number, and even a board be placed between the invisible writing and the second liquid, it will have the same effect, and turn the writing black, penetrating the wood and paper without leaving any traces of its action, which is certainly surprising; but a fetid smell, occasioned by the mutual action of the liquids, deters many from making the experiment. I am, however, of opinion, that I could improve this secret by a more refined chemical preparation, so that it should perform its effect through a wall. This secret I received, in exchange for others, from J. Brosson, a learned and ingenious apothecary of Montpelier.

[265] Tachenii Hippocraticæ Medicinæ Clavis, p. 236. 1669.

[266] Collectanea Chymica Leydensia, edidit Morley. Lugd. Bat. 1684, 4to, p. 97.

[267] For an account of various kinds of secret writing see Halle, Magie oder Zauberkräfte der Natur. Berlin, 1783, 8vo, v. i. p. 138.

[268] Hist. et Mém. de l’Acad. des Sciences à Paris, 1737, pp. 101 and 228.

[269] Historia Cadmiæ fossilis, sive Cobalti. Berl. 1744.

[270] This account, together with Teichmeyer’s receipt for preparing it, may be found in Commercium Litterarium Norimbergense, 1737, p. 91.

[271] “Copiosius minera bismuthi tam ab aqua forti quam ab aqua regia dissolvitur, restante pulvere albo corroso; solutio in aqua forti roseum colorem sistit, quæ si sali in aqua soluto, secundum præscriptum D. J. W. in clave, affundatur, abstrahatur, ex residuo extrahitur sal roseum, quod pulverisari et cum spiritu vini extrahi potest: adeoque hæc autrix jam anno 1705 publice totum processum et fundamentum sic dicti atramenti sympathetici, quod a calore viridescit, evulgavit.”--Pot, Observ. Chym. collectio prima. Berolini, 1739, p. 163.

[272] So thinks Gesner in Selecta Physico-œconomica, or Sammlung von allerhand zur Naturgeschichte gehörigen Begebenheiten. Stutgard, vii. p. 22.

[273]

[_Inks formed of solutions _and washed with solutions
of the following salts_, of_ _become_
Muriate of antimony, tincture of galls, yellow.
Green vitriol, tincture of galls, black.
Nitrate of cobalt, oxalic acid, blue.
Subacetate of lead, hydriodic acid, yellow.
Arseniate of potash, nitrate of copper, green.
Nitrate of copper, prussiate of potash, brown.
Solution of gold, muriate of tin, purple.
Perchloride of mercury, hydrochlorate of tin, black.]

DIVING-BELL.

The first divers learned their art by early and adventurous experience, in trying to continue under water as long as possible without breathing; and, indeed, it must be allowed that some of them carried it to very great perfection. This art, however, excites little surprise; for, like running, throwing, and other bodily dexterities, it requires only practice; but it is certain that those nations called by us uncultivated and savage excel in it the Europeans[274], who, through refinement and luxury, have become more delicate, and less fit for such laborious exercises.

In remote ages, divers were kept in ships to assist in raising anchors[275], and goods thrown overboard in times of danger[276]; and, by the laws of the Rhodians, they were allowed a share of the wreck, proportioned to the depth to which they had gone in search of it[277]. In war, they were often employed to destroy the works and ships of the enemy. When Alexander was besieging Tyre, divers swam off from the city, under water, to a great distance, and with long hooks tore to pieces the mole with which the besiegers were endeavouring to block up the harbour[278]. The pearls of the Greek and Roman ladies were fished up by divers at the great hazard of their lives; and by the like means are procured at present those which are purchased as ornaments by our fair.

I do not know whether observations have ever been collected respecting the time that divers can continue under water. Anatomists once believed that persons in whom the oval opening of the heart (_foramen ovale_) was not closed up, could live longer than others without breathing, and could therefore be expert divers. Haller[279], however, and others, have controverted this opinion; as people who had that opening have been soon suffocated, and as animals which have it not can live a long time under water: besides, when that opening is perceptible in grown persons, it is so small as not to be sufficient for that purpose, especially as the _ductus arteriosus_ is scarcely ever found open.

The divers of Astracan, employed in the fishery there, can remain only seven minutes under water[280]. The divers in Holland seem to have been more expert. An observer, during the time they were under water, was obliged to breathe at least ten times[281]. Those who collect pearl-shells in the East Indies can remain under water a quarter of an hour, though some are of opinion that it is possible to continue longer; and Mersenne mentions a diver, named John Barrinus, who could dive under water for six hours[282]. How far this may be true I shall leave others to judge.

[The various statements regarding the length of time during which divers can remain under water, unaided by apparatus for renewing the supply of atmospheric air, are not borne out by the experience of those who have carefully observed and noted these phænomena. The average time which human beings can remain in the water under these conditions, is one and a half or two minutes[283]; extraordinary cases are attested where five and even six minutes have elapsed, but these are exceedingly rare instances and far beyond the average; no instance of a longer time than this is recorded on credible authority. Some interesting remarks on this point were made not long since by a member of the Asiatic Society to Dr. Faraday. The lungs in their natural state are charged with a large quantity of impure air; this being a portion of the carbonic acid gas which is formed during respiration, but which, after each expiration, remains lodged in the involved passages of the pulmonary tubes. By breathing hard for a short time, as a person does after violent exercise, this impure air is expelled, and its place is supplied by pure atmospheric air, by which a person will be enabled to hold his breath much longer than without such precaution. Dr. Faraday states, that although he could only hold his breath, after breathing in the ordinary way, for about three-fourths of a minute, and that with great difficulty, he felt no inconvenience, after making eight or ten forced respirations to clear the lungs, until the mouth and nostrils had been closed more than a minute and a half; and that he continued to hold breath to the end of the second minute. A knowledge of this fact may enable a diver to remain under water at least twice as long as he otherwise could do. It is suggested that possibly the exertion of swimming may have the effect of occasioning the lungs to be cleared, so that persons accustomed to diving may unconsciously avail themselves of this preparatory measure.]

It is certain, however, that men began very early to contrive means for supplying divers with air under the water, and of thereby enabling them to remain under it much longer. For this purpose the diving-bell, _campana urinatoria_, was invented. Those who had no idea of this machine, might have easily been led to it by the following experiment. If a drinking-glass inverted be immersed in water, in such a manner that the surface of the water may rise equally around the edge of the glass, it will be found that the glass does not become filled with water, even when pressed down to the greatest depth; for where there is air no other body can enter, and by the above precaution the air cannot be expelled by the water. In like manner, if a bell of metal be constructed under which the diver can stand on a stool suspended from it so that the edge of the bell may reach to about his knee, the upper part of his body will be secured from water, and he can, even at the bottom of the sea, breathe the air enclosed in the bell.

The invention of this bell is generally assigned to the sixteenth century, and I am of opinion that it was little known before that period. We read, however, that even in the time of Aristotle divers used a kind of kettle to enable them to continue longer under water; but the manner in which it was employed is not clearly described.

The oldest information we have respecting the use of the diving-bell in Europe is that of John Taisnier, quoted by Schott[284]. The former, who was born at Hainault in 1509, had a place at court under Charles V., whom he attended on his voyage to Africa. He relates in what manner he saw at Toledo, in the presence of the emperor and several thousand spectators, two Greeks let themselves down under water, in a large inverted kettle, with a burning light, and rise up again without being wet. It appears that this art was then new to the emperor and the Spaniards, and that the Greeks were induced to make the experiment in order to prove the possibility of it. After this period the use of the diving-bell seems to have become still better known. It is described more than once in the works of Lord Bacon, who explains its effects, and remarks that it was invented to facilitate labour under the water[285].

In the latter part of the seventeenth century the diving-bell was sometimes employed in great undertakings. When the English, in the year 1588, dispersed the Spanish fleet called the Invincible Armada, part of the ships went to the bottom near the Isle of Mull, on the western coast of Scotland; and some of these, according to the account of the Spanish prisoners, contained great riches. This information excited, from time to time, the avarice of speculators, and gave rise to several attempts to procure part of the lost treasure. In the year 1665, a person was so fortunate as to bring up some cannon, which, however, were not sufficient to defray the expenses. Of these attempts, and the kind of diving-bell used, an account has been given by a Scotsman named Sinclair[286]; but Paschius[287], Leupold[288] and others falsely ascribe the invention of this machine to that learned man. He himself does not lay claim to this honour; but says only, that he conversed with the artist and measured the machine.

Some years after attempts of the like kind were renewed. William Phipps, the son of a blacksmith, born in America in 1650, and who had been brought up as a ship-carpenter at Boston, formed a project for searching and unloading a rich Spanish ship sunk on the coast of Hispaniola, and represented his plan in such a plausible manner, that king Charles II. gave him a ship, and furnished him with every thing necessary for the undertaking. He set sail in the year 1683; but, being unsuccessful, returned again in great poverty, though with a firm conviction of the possibility of his scheme. He endeavoured, therefore, to procure another vessel from James II., who was then on the throne; but as he failed in this, he tried to find the means of executing his design by the support of private persons, and, according to the prevailing practice, opened for that purpose a subscription. At first he was laughed at; but at length the duke of Albemarle, son of the celebrated General Monk, took part in it, and advanced a considerable sum to enable him to make the necessary preparations for a new voyage. Phipps soon collected the remainder; and in 1687 set sail in a ship of two hundred tons burthen to try his fortune once more, having previously engaged to divide the profit according to the twenty shares of which the subscription consisted. At first, all his labour proved fruitless; but at last, when his patience was almost entirely exhausted, he was so lucky as to bring up, from the depth of six or seven fathoms, so much treasure, that he returned to England with the value of two hundred thousand pounds sterling. Of this sum he himself got about sixteen, others say twenty thousand, and the duke ninety thousand pounds. After he came back, some persons endeavoured to persuade the king to seize both the ship and the cargo, under a pretence that Phipps, when he solicited for his Majesty’s permission, had not given accurate information respecting the business. But the king answered, with much greatness of mind, that he knew Phipps to be an honest man, and that he and his friends should share the whole among them, had he returned with double the value. His Majesty even conferred upon him the honour of knighthood, to show how much he was satisfied with his conduct. This Phipps was afterwards high sheriff of New England, and died at London, greatly respected, in 1693. This affair was attended with such good consequences to the duke of Albemarle, that he obtained from the king the governorship of Jamaica, in order to try his fortune with other ships sunk in that neighbourhood. But whether it was that the gold had been already taken from the one before-mentioned, or that, when the vessel went to pieces, the sea had dispersed the cargo, it is certain that nothing further was found worth the labour of searching for[289].

In England, however, several companies were formed, and obtained exclusive privileges of fishing up goods on certain coasts, by means of divers. The most considerable of these was that which, in 1688, tried its success at the Isle of Mull, and at the head of which was the earl of Argyle. The divers went down to the depth of sixty feet under water, remained there sometimes a whole hour, and brought up gold chains, money, and other articles, which, however, when collected, were of very little importance[290]. Without giving more examples of the use of the diving-bell, I shall now mention some of those who, in later times, have endeavoured to improve it. That this machine was very little known in the first half of the sixteenth century, I conclude from the following circumstance. To the oldest edition of Vegetius on the art of war, there are added, by the editor, some figures, of which no explanation is given in the book. Among these is represented a method of catching fish with the hands, at the bottom of the sea. The apparatus for this purpose consists of a cap, which is fitted so closely to the head of the diver that no water can make its way between; and from the cap there ascends a long leather pipe, the opening of which floats on the surface of the water. Had the person who drew these figures been acquainted with the diving-bell, he would certainly have delineated it rather than this useless apparatus[291]. Of the old figures of a diving machine, that which approaches nearest to the diving-bell is in a book on fortification, by Lorini; who describes a square box bound round with iron, which is furnished with windows, and has a stool affixed to it for the diver. This more ingenious contrivance appears, however, to be older than that Italian; at least he does not pretend to be the inventor of it[292].