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DUMAS “Dumas is a perfect gentleman in his manners, and wears his ribbons gracefully; his lectures are minute, without being tedious in detail. I consider him to be a very first-rate expounder of the doctrines of affinities. He has a very large and attentive class, and does not glare around him like some dirty and mischievous hyæna, nor affect the style of a rhetorician, while he is adding an oxide of antimony to a saturated solution of potash. His lectures abound in the most interesting facts; bis experiments always succeed; what he presents to you unostentatiously, you remember easily, provided you are fortunate enough to hear it. Of the miscellaneous application of chemistry to arts, he indulges his class with an occasional and judicious selection, for it is clear that a course of chemistry should never merge into dissertations on dyeing and calico-printing.

Oxide of lead, water, and any fat substance, duly mixed and heated, will produce a soap; but the same substance treated with soda or potash is preferable. The manufacturers of Marseilles (which supplies almost all France with its soap) generally employ potash, though soda is sometimes used. Soaps are true salts; that is, they have an alkaline base united with one of three acids, either the oleïc, margaric, or cetic; the first being contained in oils, the second in animal fats, the third in spermaceti. Soaps from which the glycerine* has not been extracted, spoil in a short time, and therefore it is indispensable to effect a separation. Fortunately, this separation is easily managed; nothing more being required for the purpose than to mix sea-water with the oil which has become pasty in its progress towards perfect soap. A great deal of water (nearly 50 per cent) remains in soap after it is solidified. The different colours of soap are produced in different ways; protoxide of iron makes it blue; nut-galls black; a green colour is formed by indigo ; transparent soaps are made by solution in alcohol ; soap for washing in sea water (which has not yet been made in France) contains from 45 to 50 per cent of resin.”

As to M. Dumas, nothing can be more appropriate than the sketch here given of him. On entering his class-room, he does not, like M. Thenard, plunge at once in medias rest, and without preface recapitulate the whole of his last lecture, but carefully examining most of the phials which contain the elements of his experiments, he sees that everything is in order, and then taking out the papers containing the heads of his discourse, he straightens them, glances his eye over them, and after pausing a moment commences his address. His conclusion of the last of one of his courses was highly characteristic : “ Mon intention n'a point été de décrire la pratique des arts, mais bien d'en éclairer la théorie. Ces détails scientifiques qui effarouchent les fabricans d'un certain âge, ne seront qu'un jeu pour leurs enfans, quand ils auront appris dans leurs collèges un peu plus de mathématiques et un peu moins de Latin; un peu plus de Chimie, et un peu moins de Grec !” [“My intention has not been to describe the practice of the arts, but to elucidate clearly their theory. These scientific details, which now terrify the adult manufacturer, will be mere trifles to his children when they shall be taught at school-a little more mathematics and a little less Latin; a little more Chemistry, and a little less Greek!”] Everything he does has an air of earnestness and calmness. * The sweet principle of oils.

+ Over head and ears. VOL. I.

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His appearance is much in his favour; and you see at once from his face that he is a man of sound judgment, cool research, and firmness of character; yet, at the same time, that his mind possesses a great deal of delicacy and refinement. In his style, he is quiet, unpretending, accurate, and minute: warming seldom with his subject, although convincing you continually that he is perfectly master of it. He is the most gentlemanlike neat-looking professor at the Sorbonne.

Leaving the Sorbonne to visit the College of France, Mr. North presents us with the following bit of forcible chiaro-oscuro and rich colour in the professor of general experimental physics,

AMPERE. “ The friend of Davy, and whilome one of the great natural philosophers of France, is selected for this sketch, not from the space he at present occupies in science, but for la petite comédie que voici *, and the amiable old age he exhibits. You see a venerable octogénairet, of small stature, clad in a coat of grotesque cut, on which the marks of climacterical decay are as visible as upon the excellent old man who has borne it for a quarter of a century. He has parted with his teeth, his memory, and his elasticity of step, but he retains his bonhommie, his delightful mannerism, and ever and anon exhibits some flickerings of that enthusiasm in the cause of science with which he began life, and without which nothing is to be done. I dare not, however, meddle with the splendid fragments of that genius which so often startles you into the conviction that a great man is really addressing you, I have been present at several amusing little scenes enacted between himself and his pupils : and one or two are so illustrative of amusing simplicity and a not-tobe-superannuated good-nature, that I shall venture to try their effect at second-hand. On the very first day I went to hear him (it was an introductory lecture) he had so filled the Slate with first and secondary branches of the goodly tree of science as to leave no room for more boughs, unless by topping the head, and abridging the undue growth of the original shoots. Space was wanted, and the remedy should have been at hand; but, lo! the sponge had disappeared, and could nowhere be found, though the class showed much empressement in seeking it. At last, with a look most comically solemn, the old gentleman drew out his cotton representative for a foulard, and looking first at the slate and then at the mouchoirs, plainly could not make up his mind to sully its gaudy colours by exacting from it the office of the sponge. But while necessity and reluctance were contending for the mastery on his features, the sponge was picked up by one of the students, and eagerly presented to M. Ampère, whose delight and manner of expressing it were irresistibly comic. Seizing it between both his hands, as if to be sure that it was not the shadow of the veritable detergent, but the very substance that he held, he hastened to the door, and putting his head out, called to his assistant, à la Molière, in the happiest and most unconscious imitation of the de Pourceaugnac accent-Je l'ai trouvé ; c'est à dire, on l'a trouvé-il n'entend pasą(aside). Monsieur! ... Ecoutez donc ! Then, at the highest pitch of his voice, Monsieur! ne vous donnez pas la peine de la chercher; je Pai ici-on vient de la ramasser." [I have found it; that is to say, it is found. He doesn't hear me-(aside).—Monsieur! I say, Monsieur, don't trouble yourself about it; I have got it here—they've just picked it up!'] Then, quite regardless, and apparently unconscious of what the French journalists call' une vive explosion d'hilarité *" from the class, he resumed as if nothing had occurred. He had been lecturing on the polarization of light and heat, and had assumed a square ruler and a pasteboard almanac to represent a cylindrical ray and a transparent medium of transmission, when gradually warming with his subject, he began (as one is apt to do in lecturing) to describe parabolas with his ruler, one of which encountered the tumbler (which is here d'usaget), and broke the pieces of glass into his eau sucrée. -(without eau sucrée nobody could get on with a lecture at the College de France or the Sorbonne, though law and physic lecture with unlubricated fauces). Out of this half-demolished glass, he was presently preparing to drink, when half-a-dozen voices at once called out— Monsieur Ampère! eh! Monsieur Ampère, qu'allez-vous donc faire ?' [Monsieur Ampère, oh Monsieur Ampère, what are you going to do ?'] but he, nothing heedful of these exclamations, raised the tumbler to his lips, and began to sip its now dangerous contents. In an instant one of the foremost in the class springs forward and seizes the old mau's hand, another wrests the tumbler from his grasp. A scene! profound silence in the class! The venerable man looks at them ironically, “Thank you, gentlemen !-very kind of you l-but you are giving yourselves unnecessary trouble; I took it for granted that my class understood the laws of gravitation :—with your permission, gentlemen, I will first drink my eau sucrée, which I want, and will then give you a hint which you appear to want. He now drank without further molestation, and then drawing in a long breath.— Eh ! comment, Messieurs, voulez vous qu'il est eu du danger !-ne savez-vous donc pas que le verre est plus pesant que l'eau,- [* What, gentlemen! then you thought there was some danger! but arn't you aware that glass is heavier than water? And did you not observe how careful I was to drink the contents of the tumbler at a reasonable argle?'] Then, taking up the tumbler, he continued to incline it over the table till it was nearly horizontal, and so on, till the pieces of glass fell out, and the class laughed. Ah! si je l'avois bu d cette angle !mais j'ai été plus adroit !!”—['Ah! if I had drunk at this inclination!but I was too knowing for that.'] Here (for it was at the end of his lecture that this little episode occurred) a bright-eyed damsel went up and asked some question respecting the course of rays of light through certain media, but whether old Ampère referred her to his heart, as we should have done, we could not hear. She coloured, however; her eyes seemed pleased with the interpretation given to her question, whatever it might have been, and they walked out together, a ‘January and May,' separated only by the insecure partition of the pasteboard almanac which the elder of the months still kept in his hand.”

* The little farce which follows. * A real Bandana.

+ An eighty-year old. § Aandkerchief.

These specimens have raised our anticipations to a high pitch. On the left bank of the Seine, and nearer its stream, there are many first-rate subjects which we trust are already sketched in, and safely deposited in the portfolio of the artist. It is for these that we shall eagerly seize and cut open succeeding Blackwoods; and we think that a large class of our readers will sympathize with us.

* A loud burst of merriment. + Customary.

# Sugar and water.

A POPULAR COURSE OF CHEMISTRY.

I.

INTRODUCTION. It may not be uninteresting to the general reader, and the juvenile student, to present a brief, general, and popular view, of the mysterious art of Alchymy; and thus exhibit the source from whence emanated the brilliant science of Chemistry; this paper will, therefore, be devoted to the subjects of the olden art, as introductory to those of the modern science. Enthusiasm for a favourite object not unfrequently estranges men from the path of patient investigation, and leaves far behind their better discretion : this is strongly exemplified in the case of those authors, who, in their zeal for very remote antiquity, pretend that alchymy is as ancient as the world, and that some of the personages spoken of in the earlier pages of the sacred writings, not only understood the art, but also practised it to a very great extent. Giving up this distant period, others ascribe the origin of the art to Greek ecclesiastics during the fifth and sixth centuries; and even assert that alchymical manuscripts of these dates are yet in existence; but suspicions may be very reasonably entertained that they are forgeries of a far later age. The precise origin of alchymy is involved in the darkest and deepest obscurity, which it is impossible to penetrate; but it would appear that the claims of the Arabians are stronger and better authenticated than those of the Greeks: an Arabian writer of the seventh century, named Geber, is generally admitted to have been the first well-authenticated writer on, and practiser of, alchymy. The name of the art, and many of the terms employed in its practice, bespeak an Arabic origin: it would appear that the word ALCHYMY is compounded of the Arabic particle Al, signifying the, and Kema, dark or secret. Alkema, therefore, meaning The Dark Art, or The Secret Art, its earliest disciples were called Alchymists, and afterwards Adepts.

The writings of Geber attempted to prove that all metals are composed of mercury and sulphur; and that, by altering the proportions of these two substances in any of the baser metals, such as tin or lead, they would assume the properties of the nobler metals, gold and silver.

This change was usually styled Transmutation; and it was sought to be effected through the agency of a substance (spoken of for the first time in the writings of Geber), called The Philosophers' Stone, a fragment of which projected” upon any base metal in a state of fusion, would cleanse it from its impurities, and transmute it into either gold or silver, according to the will of the operator. The principles of this alluring art, “ like the refractory spirits of Arabian romance," soon escaped from the bondage of those who had first conjured them into existence; and quitting the Eastern clime they were introduced into Europe, probably on the return of the Crusaders. Spain first swallowed the golden bait; her example was followed with incredible rapidity by Germany, Italy, France, and England; and alchymy was cultivated with a zeal bordering upon madness, from the eleventh to the sixteenth century. Hundreds of volumes made their appearance in these centuries, relating to the art of alchymy; but it must not be imagined that these writings were couched in ordinary language, or in such plain terms that every one might read and profit by them; for, on the contrary, the writers deemed their secrets far too valuable to be exposer! so openly, and therefore invented a curious style of language, replete with enigma, anagram, and mysterious symbol, which none but the initiated could decipher; novices who wished to penetrate the arcana of the dark art, were bound by an awful promise to abstain from revealing its mysteries, or even from holding converse touching them, excepting with those who could produce the requisite sign or counter-sign: and thus, although the secrets of alchymy were known to many, yet the adepts all held good fellowship.

It may, perhaps, be worth while to present a specimen or two of the style of these writings and their interpretation.

In discoursing concerning the metals,-a class of bodies particularly tortured by the alchymists; they use the terms Sol, Lana, Mercury, Venus, Mars, Jupiter, and Saturn, meaning gold, silver, quicksilver, copper, iron, tin, and lead; these seven metals were those chiefly known to them, and were imagined to possess some mystical relation to the seven planetary bodies both in aspect and properties. They also denoted them by the following symbols :- Gold, Silver ; $ Mercury; ¢ Copper; Iron ; 24 Tin; h Lead.

Besides these names and symbols, they were known by a variety of others; thus, Gold is sometimes called “ the Sun terrestrial,” “the King,” “the Lyon;" Silver, “ the Queen,” “ the Wife of Gold ;” Mercury, “ the Mighty Childe and Sonne of Gold and Silver,” “the Eagle,” &c.

The alchymist in appending his name to his writings, almost invariably concealed it in an anagram ; thus, for example, " ANGELUS DOCE MIHI JUS*,” will, if the letters are properly arranged, present the name of a far-famed alchymist, MICHAEL SENDIVOGIUS. Another writer appends to his writings the words TWICE FIVE HUNDRED,” which simply mean the initial letters of his name W. C.; the old way of printing the letter W, being thus VV, therefore VVC is twice five hundred.

The following is a specimen of their enigmatical writing “Hide and couple in a transparent den, the eagle and the lyon, shut the door close, so that their breath go not out, and strange air enter not in. The eagle at their meeting will tear in pieces and devour the lyon, and then be taken with sleep.” The interpretation of this is probably as follows:Put together in a glass vessel, quicksilver and gold, close the mouth of the vessel accurately, by melting the glass, to prevent the vapour of the quicksilver from escaping, or being mixed with common air. The quicksilver will speedily soften it, and losing its fluidity, will form an amalgam.

Here is another specimen :-“ Take the most ravenous grey wolf, which, by reason of his name, is subject to valorous Mars; but which, by the genesis of his nativity is the son of old Saturn. He is very hungry, cast unto him the king's body that he may be nourished by it, and when he hath devoured the king, make a great fire, into which cast the wolf that he be quite burned, then will the king be at liberty again." This curious sentence may be interpreted thus:

Angel teach me right.

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