Kitabı oku: «A History of Inventions, Discoveries, and Origins, Volume I (of 2)», sayfa 26

If we go back to the period of Philip III. of Spain, we shall then see the interest and importance attached to this great discovery. As early as 1598, this monarch offered a reward of 100,000 crowns to any person who should discover the means of finding the longitude of a ship at sea; but what was the opinion then entertained of the nature of the task to be accomplished by means of the balance-watches then in use, may be gathered from an expression of Morin, who wrote about the year 1630, and who in speaking to the Cardinal Richelieu of the difficulty of constructing an instrument which should keep time to the requisite degree of accuracy for that purpose, is reported to have said, “Id verò an ipsi dæmoni nescio, homini autem suscipere scio esse stultissimum¹¹²².”

We have not said much on the beautiful discovery of the law of isochronism, of the balance-spring, on which the higher adjustment of clocks and watches so entirely depend, as an elaborate essay on this subject by Charles Frodsham, F.R.A.S., is in the hands of the publisher, and will shortly be circulated.

Some very ingenious contrivances have within the last few years been effected in the application of the electric fluid as a source of motive power to clocks and chronometers, and they offer peculiar advantages in the great simplicity of the apparatus in which wheels are dispensed with, hence friction is reduced to a minimum. Their invention is a subject of dispute between Professor Wheatstone and Mr. Alexander Bain¹¹²³. We shall briefly describe Mr. Bain’s clock. His source of electricity is obtained by fixing galvanic plates in moist earth. The clock consists of a pendulum, the bob of which vibrates between the poles of two permanent magnets, the opposite poles of which face one another. A small platinum-ball is affixed to the upper part of a small brass stem, which is free for lateral motion, being fastened below to a light spindle carried by the upper part of the pendulum-rod. A wire coated with silk is attached to the lower end of the suspension-spring of the pendulum. It is led down the back of the rod (which is composed of wood) and then coiled longitudinally in many convolutions around the edge of the bob in a groove. It is then taken up the back of the rod and terminates in the bearings of the spindle. The pendulum is suspended from a metal bracket fixed to the back of the case, and to which one of the poles of the battery is attached. Two pins are fixed horizontally, parallel with the platinum-ball, leaving space for its lateral motions, and at such a distance that the ball alternately comes into contact with each pin, when the pendulum has reached the opposite extremity of its arc. The other pole of the battery is placed in contact with the metal bracket which supports one of the pins. As long as the platinum-ball rests on the pin projecting from the pin-bracket to which the second pole of the battery is attached, a constant current of electricity is established and passes through the earth, the plates and the wires. But when the pendulum is set in motion by being drawn on one side, the point of support of the rod carrying the platinum-ball is thus moved to the same side, hence the centre of gravity of the platinum-ball being removed beyond its base, it falls upon the opposite pin. This motion of the ball lets on and cuts off the flow of electricity, at or near the ends of the vibrations of the pendulum, so that the convoluted wire of the bob is alternately attracted and repelled by the magnets at the proper points of its vibrations, and thus a continual motion is kept up. Mr. Bain has also contrived arrangements by which a great number of clocks may be worked simultaneously or in rotation; as also by which ordinary clocks may be made to keep time. The latter are effected by transmitting a current of electricity once in every four hours from a regulating clock. As the details connected with these valuable contrivances can hardly be followed without figures, we must rest satisfied with referring the reader to Mr. Bain’s work, before cited.]

QUARANTINE

Of all the means by which in modern times the infection of that dangerous malady, the plague, has been so much guarded against, that according to general opinion, unless the Deity render all precaution useless, it can never again become common in Europe, the most excellent and the most effectual is, without doubt, the establishment of quarantine¹¹²⁴. Had not history been more employed in transmitting to posterity the crimes of princes, and particularly the greatest of them, destructive wars, than in recording the introduction of such institutions as contribute to the convenience, peace, health and happiness of mankind, the origin of this beneficial regulation would be less obscure than it is at present. At any rate, I have never yet been so fortunate as to obtain a satisfactory account of it; but though I am well-aware that I am neither acquainted with all the sources from which it is to be drawn, nor have examined all those which are known to me, I will venture to lay before my readers what information I have been able to collect on the subject, assuring them at the same time, that it will afford me great pleasure if my attempt should induce others fond of historical research to enlarge it.

The opinion that the plague was brought to Europe from the East, is, as far as I am able to judge, so fully confirmed, that it cannot be any longer doubted; though it is certainly true, that every nation endeavours to trace the origin of infectious disorders to other people. The Turks think that the plague came to them from Egypt; the inhabitants of that country imagine that they received it from Ethiopia; and perhaps the Ethiopians do not believe that this dreadful scourge originated among them¹¹²⁵. As the plague however has always been conveyed to us from the East, and has first, and most frequently, broken out in those parts of Europe which approach nearest to the Levant, both in their physical and political situation, those I mean which border on Turkey, and carry on with it the most extensive trade, we may with the more probability conjecture that these countries first established quarantine, the most powerful means of preventing that evil. If further search be made in regard to this idea, we shall be inclined to ascribe that service to the Venetians, a people who, when the plague began to be less common, not only carried on the greatest trade in the Levant, but had the misfortune to become always nearer neighbours to the victorious Turks. It is also probable that the Hungarians and Transylvanians soon followed their example in this approved precaution, as the Turks continued to approach them; and this agrees perfectly with everything I have read in history.

In the first centuries of the Christian æra, it does not seem to have been known that infection could be communicated by clothing and other things used by infected persons. The Christians all considered the plague as a divine punishment, or predestinated event, which it was as impossible to avoid as an earthquake; and the physicians ascribed the spreading of it to corrupted air, which could not be purified by human art. The Christians therefore gave themselves up, like the Turks at present, to an inactive and obstinate resignation in the will of God, and hoped by fasting and prayer to hasten the end of their misfortune.

But after the plague in the fourteenth century, which continued longer than any other, and extended over the greater part of Europe, the survivors found that it was possible to guard against or prevent infection; and governments then began to order establishments of all kinds to be formed against it. The oldest of which mention has yet been found in history, are those in Lombardy and Milan of the years 1374, 1383 and 1399¹¹²⁶.

In the first-mentioned year the Visconte Bernabo made regulations, the object of which was to guard against the spreading of the plague by intercourse and mixing with those who were infected; and with that view it was ordered, that those afflicted with this disease should be removed from the city, and allowed either to die or to recover in the open air. Those who acted otherwise were to suffer capital punishment, and their property was to be confiscated. But twenty-five years after it was strictly commanded that the clothes and things used by those who had the plague should be purified with great care: and in 1383 it was forbidden under severe punishment to suffer any infected person to enter the country. These means, however imperfect, must have been attended with utility, because they were again employed during a new danger of the same kind in the fifteenth century.

Brownrigg, an Englishman, who wrote a book on the means of preventing the plague, says, that quarantine was first established by the Venetians in the year 1484¹¹²⁷, but like his learned countryman Mead, who assigns the same year, without adducing any proofs¹¹²⁸. I imagined that I should find some more certain information respecting this point in Le Bret’s History of the Republic of Venice; but as that historian does not mention, as the title professes, the original sources from which he derived his materials, his work is less worthy of credit. He tells us however that the grand council in 1348, chose three prudent persons, whom they ordered to investigate the best means for preserving health, and to lay the result of their inquiry before the council. The plague which broke out afterwards in 1478, rendered it necessary that some permanent means should be thought of, and on that account a peculiar magistracy consisting of three noblemen, with the title of sopra la sanità, was instituted in 1485. As these were not able to stop the progress of the disease, the painful office was imposed upon them, in 1504, of imprisoning people against whom complaints might be lodged, and even of putting them to death; and in 1585 it was declared, that from the sentence of these judges there should be no appeal. Their principal business was to inspect the lazarettos erected in certain places at some distance from the city, and in which it was required that all persons and merchandize coming from suspected parts should continue a stated time fixed by the laws. The captain of every ship was obliged also to show there the bill of health which he had brought along with him.

As Le Bret produces no proof that quarantine was established by the Venetians so early as he says, I cannot help suspecting that he is mistaken respecting the year (1348), and conjecture that it ought to be 1448, or perhaps 1484. I have not been able however to resolve my doubt; for, in examining different Italian writers, I find that various years are given¹¹²⁹. The institution of the council of health (sopra la sanità) is mentioned by Bembo; but I cannot discover from him to what year he alludes¹¹³⁰. His countryman Lancellotti, who undoubtedly must have understood him well, makes it to be 1491¹¹³¹. Caspar Contarenus, who died in 1542, in the sixtieth year of his age, mentions no particular period, and only says that the institution had been formed not long before his time¹¹³². The islands on which the pest-houses were erected, were called il Lazaretto vecchio and il Lazaretto nuovo. In the elegant description of Venice, ornamented with abundance of plates, below mentioned, it is remarked that the pest-house on the former island was built in 1423, and that on the latter in 1468¹¹³³. The same account is given in the newest and best Topography of Venice¹¹³⁴.

The Venetians are entitled to the merit of having improved the establishments formed to prevent infection; and that their example was followed in other countries is generally admitted. But the year in which quarantine was first ordered by them to be performed is uncertain. Muratori¹¹³⁵, following Lorenzo Candio, gives the year 1484, and Howard¹¹³⁶ says that the college of health was instituted in 1448.

Brownrigg affirms that letters of health, in which he confides more than in quarantine, were first written in 1665 by the consuls of the different commercial nations, but they are much older, for Zegata¹¹³⁷ asserts that they were first established in 1527, when the plague again made its appearance in Europe.

This much is certain, that all these means against infection, which, though far from being perfect, have secured Europe from this misfortune, were not invented or proposed by physicians, but ordered by the police, contrary to their theory. The latter seem to have known, at an early period, the most dangerous causes of infection, and to have formed at a very great expense precautionary means, the observance of which was enforced under pain of the severest punishment.

Why the space of forty days was chosen as a proof I do not know. It arose no doubt from the doctrine of the physicians in regard to the critical days of many diseases. The fortieth day seems to have been considered as the last or extreme of all the critical days; on which subject many physicians appear to have entertained various astrological conceits¹¹³⁸. On the Turkish frontiers this period was reduced under the emperor Joseph II. to twenty days¹¹³⁹.

[With respect to the quarantine establishments in this country, Mc Culloch observes that they are exceedingly defective. Even in the Thames there is not a lazaretto where a ship from a suspected place may discharge her cargo and refit; so that she is detained, frequently at an enormous expense, during the whole period of quarantine, while if she have perishable goods on board, they may be very materially injured. The complaints as to the oppressiveness of quarantine regulations are almost wholly occasioned by the want of proper facilities for its performance. Were these afforded, the burdens it imposes would be rendered comparatively light.

The existing quarantine regulations are embodied in the act 6 George IV. c. 78, and the different orders in council issued under its authority. These orders specify what vessels are liable to perform quarantine, the places at which it is to be performed, and the various formalities and regulations to be complied with.]

PAPER-HANGINGS

Three kinds of paper-hangings have for some time past been much used on account of their beautiful appearance and their moderate price. The first and plainest is that which has on it figures printed or drawn either with one or more colours. The second sort contains figures covered with some woolly stuff pasted over them; and the third, instead of woolly stuff, is ornamented with a substance that has the glittering brightness of gold and silver. It appears that the idea of covering walls with parti-coloured paper might have readily occurred, but the fear of such hangings being liable to speedy decay may have prevented the experiment from being made. In my opinion the simplest kind was invented after the more ingenious, that is to say, when the woolly or velvet kind was already in use¹¹⁴⁰. The preparation of them has a great affinity to the printing of cotton. Wooden blocks of the like kind are employed for both; plates of copper are also used; and sometimes they are painted after patterns. Artists possess the talent of giving them such a resemblance to striped and flowered silks and cottons, that one is apt to be deceived by them on the first view. Among the most elegant hangings of this kind, may be reckoned those which imitate so exactly every variety of marble, porphyry, and other species of stones, that when the walls of an apartment are neatly covered with them, the best connoisseur may not without close examination be able to discover the deception. That the resemblance may be still greater, a hall may be divided by an architect into different compartments by pillars, so as to have the appearance of a grand piece of regular architecture. Whether M. Breitkopf at Leipsic was the inventor of this kind of hangings, I do not know, but it is certain that he brought it to great perfection.

The second kind, or, as it is called, velvet-paper (now called flock-paper), is first printed like the former, but the figures are afterwards wholly, or in part, covered with a kind of glue, over which is strewed some woolly substance, reduced almost to dust, so that by these means they acquire the appearance of velvet or plush. The ground and the rest of the figures are left plain; but the whole process is so complex that it is impossible to convey a proper idea of it by a short description. The shearings of fine white cloth, which the artist procures from a cloth manufactory, and dyes to suit his work, are employed for this purpose. If they are not fine enough, he renders them more delicate by making them pass through a close hair-sieve. This, as well as the third kind, was formerly made much more than at present upon canvas; and, in my opinion, the earliest attempts towards this art were tried, not upon paper, but on linen cloth. The paper procured at first for these experiments was probably too weak; and it was not till a later period that means were found out to strengthen and stiffen it by size and paste.

The invention of velvet-paper is by several French writers¹¹⁴¹ ascribed to the English; and, if they are not mistaken, it was first made known in the reign of Charles I. On the 1st of May 1634, an artist, named Jerome Lanyer, received a patent for this art, in which it is said that he had found out a method of affixing wool, silk and other materials of various colours upon linen cloth, silk, cotton, leather and different substances with oil, size and cements, so that they could be employed for hangings as well as for other purposes¹¹⁴². The inventor wished to give to this new article the name of Londrindiana, which appears however not to have continued in use. It is worthy of remark, that this artist first made attempts to affix silk upon some ground, but that method as far as I know was not brought to perfection; that he employed for the ground, linen and cotton cloth, or leather; and that no mention is made of his having used paper, though he seems not to have confined himself entirely to leather or cloth.

Tierce, a Frenchman, has however disputed this invention with the English; for he asserts that one of his countrymen at Rouen, named François, made such kinds of printed paper-hangings so early as the year 1620 and 1630, and supports his assertion by the patterns and wooden blocks which are still preserved, with the above-mentioned years inscribed on them¹¹⁴³. He is also of opinion, that some Frenchmen, who fled to England when persecuted for their religion, carried this art along with them. The inventor’s son followed this business to a great extent for more than fifty years at Rouen, and died in 1748. Some of his workmen went privately to the Netherlands and Germany, where they sold their art; and the French, therefore, with great confidence maintain, without knowing our artists and their works, that foreigners in this branch of manufacture are still far behind them. In most works of the kind my countrymen indeed are only imitators, not through want of talents to invent or to improve, but because our great people, for whom they must labour, consider nothing as fashionable or beautiful, except what has been first made by the French or the English.

I shall here observe, that Nemeitz ascribes the invention of wax-cloth-hangings, with wool chopped and beat very fine (these are his own words), to a Frenchman named Audran, who in the beginning of the last century was an excellent painter in arabesque and grotesque figures, and inspector of the palace of Luxemburg at Paris, in which he had a manufactory for hangings of that kind¹¹⁴⁴. What particular service he rendered to the art of making paper-hangings, I have not however been able to learn. Equally uncertain and defective is the information of Von Heinecken¹¹⁴⁵, that one Eccard invented the art of imprinting on paper-hangings gold and silver figures, and carried on a manufactory for such works.

In regard to the time when these hangings began to be made in Germany, I can only say that the oldest information I know respecting them is to be found in a work¹¹⁴⁶ by Andrew Glorez von Mahren, printed for the first time in 1670. It shows that the art was then very imperfect as well as little known, and that it was practised only by women upon linen for making various small articles¹¹⁴⁷.

One of the most ingenious new improvements in the art of manufacturing these hangings, consists in bestrewing them here and there with a glittering metallic dust or sand, by which they acquire a resemblance to rich gold and silver brocade. From the above-quoted work it appears that artists began very early to cover some parts of paper-hangings with silver-dross or gold-foil; but as real gold was too dear to be used for that purpose, and as imitations of it soon decayed, this method seems not to have been long continued. Instead of these, Nuremberg metallic dust as well as silver-coloured foil are employed. Metallic dust is the invention of an artist at Nuremberg, named John Hautsch, who constructed also a carriage which could be moved by the person who sat in it. He was born in the year 1595, and died in 1670. His descendants have continued to the present time the preparation of the metallic dust, which is exported in large quantities from Nuremberg, and is used in shell-work, lackered-ware, and for various other purposes. It is prepared by sifting the filings of different metals, washing them in a strong lye, and then placing them on a plate of iron or copper over a strong fire, where they are continually stirred till their colour is altered. Those of tin acquire by this process every shade of gold-colour, with a metallic lustre; those of copper the different shades of red and flame-colour; those of iron and steel become of a blue or violet; and those of tin and bismuth appear of a white or bluish-white colour. The dust, tinged in this manner, is afterwards put through a flatting-mill, which consists of two rollers of the hardest steel, like those used by gold and silver wire-drawers, but for the greater convenience a funnel is placed over them¹¹⁴⁸. I have in my possession samples of all the above kinds, which have an exceedingly beautiful appearance. This metallic dust is affixed so strongly to paper by means of a cement, that it is almost impossible to detach it without tearing the paper, as is the case with the paper-hangings procured from Aachen. In French, such paper is called papier avec paillettes. The lustre of it is so durable that it continues unaltered even on the walls of sitting-apartments. The metallic dust however has a considerable weight, which may undoubtedly injure the paper.

This inconvenience may have induced artists to employ, instead of metallic dust, that silver-coloured mica, which has been long used in the like manner. So early as the seventeenth century the miners at Reichenstein in Silesia collected and sold for that purpose various kinds of mica, even the black, which acquires a gold-colour by being exposed to a strong heat¹¹⁴⁹. The nuns of Reichenstein ornamented with it the images which they made, as the nuns in France and other catholic countries ornamented their agni Dei, by strewing over them a shining kind of talc¹¹⁵⁰. The silver-coloured mica however has not such a bright metallic lustre as metallic dust, but it nevertheless has a pleasing effect when strewed upon a white painted ground, and its light thin spangles or scales retain their brightness and adhere to the paper as long as it lasts. At present I am acquainted with no printed information respecting the method of laying on metallic dust and mica, nor do I know where artists procure the latter, which in many countries is indeed not scarce. I shall here observe, that I once saw at Petersburg a kind of Chinese paper, which appeared all over to have a silver-coloured lustre without being covered with any metallic substance, and which was exceedingly soft and pliable. It bore a great resemblance to paper which has been rubbed over with dry acid of borax. I conjecture that its surface was covered with a soft kind of talc, pounded extremely fine; but as I have none of it in my possession at present, I can give no further account of it.

[The manufacture of this important and elegant substitute for the ancient “hangings” of tapestry has undergone a gradual succession of improvements, and has now reached a high state of beauty and perfection. The patterns on these papers are sometimes produced by stencil plates, but more commonly by blocks, each colour being laid on by a separate block cut in wood or metal upon a plain or tinted ground. The patterns are sometimes printed in varnish or size, and gilt or copper-leaf applied; or bisulphuret of tin is dusted over so as to adhere to the pattern; and in what are called flock-papers, dyed wools mixed into powder are similarly applied. Powdered steatite or French chalk is used to produce the peculiar gloss known under the name of satin. Striped papers are sometimes made by passing the paper rapidly under a trough, which has parallel slits in its bottom through which the colour is delivered; and a number of other very ingenious and beautiful contrivances have lately been applied in this important branch of art. The invention of the paper-machine, by which any length of paper may be obtained, effected a great change in paper-hangings, which could formerly only be printed upon separate sheets, and were much more inconvenient to print as well as to apply to the walls¹¹⁵¹.]