History. or some multiple of these atomic ratios. The atomic weight is 5:375 or some multiple of that number. The difference between alcohol and pyroacetic spirit, if confidence can be put in the above analysis, is that alcohol contains twice as much hydrogen as pyroacetic spirit. This is rather an anomaly, considering that pyroacetic spirit is both more volatile and lighter than alcohol. It would be desirable on that account to repeat the analysis again with every possible care, in order to verify the results of MM. Macaire and Marcet. III. Pyroxylic Spirit. I do not know to whom we are indebted for the discovery of this liquid. In London and Glasgow it has been known for these 20 years, and I presume that it must have been discovered in Paris at least as early, as the manufactory of wood vinegar in that capital has existed for more than 20 years. I have been in the habit of employing it in lamps instead of alcohol for about 12 years. The first notice of it (so far as I know) in print was by M. Colin in the year 1819. He describes some of its most remarkable properties, and states his opinion that it is merely pyroacetic spirit containing an empyreumatic oil in solution. Dobereiner mentioned it in 1821, but mistook it for alcohol. MM. Macaire and Marcet made a set of experiments on it, and subjected it to analysis in 1828.+ Since that time some of its properties have been investigated by M. L. Gmelin. When wood is distilled, the products are water, acetic acid, * Ann. de Chim. et de Phys. xii. 206. + Bibliotheque Universelle, xxiv. 126. Annals of Philosophy (2d series), viii. 69. Handbuch der Theoret. Chimie, ii. 34k. pyroxylic spirit, empyreumatic oil, and a black matter which is considered as analogous to pitch or rather tar. When the watery portion, freed as well as possible mechanically from the tar, is distilled at a low heat, the first portion that comes over is the pyroxylic spirit, which may be freed from acetic acid by agitation with lime or magnesia, and then distillation at a low temperature. But it is still contaminated to a great degree with empyreumatic oil, from which it has been hitherto impossible to purify it. It may be freed from a considerable portion of this oil by diluting it with water, which causes the greatest part of the oil to separate, disengaging the diluted spirit by decantation, and afterwards rectifying it by the same processes as succeeds with alcohol till it be again freed from the water; but this process is only partially successful, a considerable portion of oil still obstinately remaining. Gmelin says it may be nearly freed from oil by mixing it with its own weight of sulphuric acid and subjecting the mixture to distillation. Chap. II. Pyroxylic spirit thus prepared is a transparent and colourless Properties, liquid, having a strong pungent and somewhat ethereal smell, which Macaire and Marcet compares to that of ants, and Gmelin to that of acetic ether; but the smell of the pyroxylic spirit made in Glasgow (with which only I am acquainted) does not resemble either of these, but is quite peculiar. Its taste is strong, hot, pungent, and very disagreeable, derived obviously in part from the empyreumatic oil which it holds in solution. Its specific gravity, in the most concentrated state in which I could procure it, was 0.8121. Macaire and Marcet found it to boil at 150°, and with this determination my experiments agree. Gmelin states its boiling point to be 137°, yet the specific gravity of the spirit which he examined was only 0.830. When completely freed from acetic acid it does not redden vegetable blues. It burns with a very pale yellow flame inclining to blue, but the light is considerably greater than that given out by alcohol. It burns all away without leaving any residue, and the only products are carbonic acid and water. It dissolves in alcohol in any proportion. With water it becomes opaque, obviously in consequence of the empyreumatic oil which it contains. It dissolves readily in oil of turpentine and in liquid potash, acquiring at the same time a yellowish colour. Camphor dissolves in it readily, but it does not dissolve olive oil. With sulphuric ether it unites likewise in all proportions. It dissolves a little sulphur and phosphorus, and is Chap. III. Sesquichlo ride of carbo. hydrogen. a good solvent of common rosin and of shell lac. Iodine is dissolved by it abundantly, and the solution has the same dark brown colour as the solution of iodine in alcohol. When the solution of this spirit in hydrated potash is distilled after an interval of a few days the pyroxylic spirit which comes over is quite free from empyreumatic oil. Here then is a method by which chemists may have it in their power to obtain this spirit in a state of purity. When mixed with nitric acid and distilled an ethereal liquid comes over, which, however, is quite different from nitric ether. When ounce measure of this spirit is mixed with 1 ounce measure of nitric acid and 2 ounce measures of muriatic acid in a flask, and a moderate heat applied, it soon begins to effervesce, and a gas comes over having an exceedingly pungent smell, and acting strongly on the nose and eyes. This gas burns with a bluish white flame. Its specific gravity I found 1945, and on analyzing it was a mixture of three gaseous bodies in the following proportions in volume: Deutoxide of azote A new gas Water absorbs 5 times its volume of this gas, and oil of turpentine 34 times its volume. The specific gravity of the new gas is 4-2361. It requires 11⁄2 times its volume of oxygen to burn it, and it forms its own volume of carbonic acid. When the combustion is made over mercury a quantity of calomel is formed at the same time. Hence it is a compound of I volume carbon vapour, I volume hydrogen gas, 1 volume chlorine gas, condensed into one volume. It is a compound of and its atomic weight is 7.625. To this gas the name of sesquichloride of carbohydrogen may be given. According to Macaire and Marcet, when pyroxylic spirit is mixed with thrice its weight of sulphuric acid and heated, a gas Sect. III, is obtained which burns with a blue flame. This spirit was subjected to analysis by Messrs. Macaire and Marcet, by volatilizing a given weight of it through red-hot black oxide of copper. The constituents deduced from this But no conclusion can be drawn from this analysis, because the spirit which they subjected to analysis was obviously contaminated with empyreumatic oil. I am very much inclined to suspect that it will be found to contain both less carbon and hydrogen compared with the oxygen than alcohol does. SECTION III.- -OF SULPHURIC ETHER. The term ether is applied by British and French writers Ether, what. indiscriminately to all the volatile liquids made by the action of acids on alcohol. But these liquids are divisible into two sets, exceedingly different from each other in their characters. One set is quite free from any portion of the acid employed in its preparation, and consists of the very same constituents as exist in alcohol, though the proportions are different; the other set consists of the acid employed in the formation of the ether, saturated with a peculiar volatile and combustible substance, which appears to be the same in all. Some of the latest chemical writers in Germany have confined the term ether to the first of these sets, and have distinguished the second set by the term naphtha. We have it not in our power to follow this example, as the word naphtha, in the English language, has been already appropriated to a very different substance. I shall satisfy myself, therefore, with separating the two kinds of ether from each other. I shall describe the first kind in this section, under the name of sulphuric ether, by which, or simply by the term ether, it is usually distinguished in this country; while in the next section I shall treat of the second kind of ethers under the name of acid ethers, though I must acknowledge that the name Chap. III. is not very appropriate. For these ethers when first formed have no acid qualities. They contain an acid indeed, but it is saturated with another substance which quite conceals its properties. But when these ethers are kept they gradually acquire acid qualities, whereas sulphuric ether may be kept for any length of time without undergoing much alteration in its History. nature.* The method of making sulphuric ether is described in the dispensatory of Valerius Cordus, published at Nuremberg about the year 1540: from which Conrad Gesner transcribed it into his Thesaurus Euonymi de Remediis Secretis, published in 1552, where it is called Oleum Vitrioli dulce. It appears to have been known, though not in a state of purity, both to Basil Valentine and Paracelsus. But in the writings of chemists published about the end of the 17th century, I have not been * It appears from the observations of Planche and Gay-Lussac, that ether when kept for several years in a vessel not quite full, and often opened, generates some acetic acid. See Ann. de Chim. et de Phys. ii. 98 and 213. M. Henry has rendered it probable that this is owing to a small quantity of acetic ether which is usually mixed with sulphuric ether. Jour. de Pharmacie, xiii. 119. + Whoever will consider the formula given for preparing this Oleum Vitrioli dulce by Gesner, will be satisfied that it was very different from the dulcified acids of the moderns, and that it must have been a mixture of alco hol, ether, and sweet oil of wine. The following is the passage of Gesner, as quoted by Hoffman, from whom has been taken the historical facts respecting the knowledge of ether possessed by the alchymistical writers.Recipe vini ardentis acerrimi et ter sublimati uncias quinque, olei vitrioli austeri tantundem, misce in venetiano vitro, et pone in cucurbitam parvam angusto orificio, et luto optimo orificium claude, dimitte ita | er integrum mensem aut duos. Deinde effunde in cucurbitam, cui sit immediate annexum I alembicum, cujus figuram subjiciemus, pone deinde in parvam fornacem, ac dimidiam ejus partem cinere obrue, postea applica recipientem et luto junc turam claude diligenter, et extrahe uncias sex vini ardentis quas infudisti. Ut vero tutius hoc fiat, pone in balneum Maria; sie solum vinum absque oleo ascendet. Cum extraxeris autem per balneum infusas uncias sex vini usti, pone id, quod residuum est, in fornacem, ut arena mediam cucurbitæ partem attingat, ac novo et vacuo recipiente eoque non magno applicato, luto juncturam diligenter claude. Accende deinde modestum ignem, et sensim extrahe omnem humiditatem quæ relicta est in cucurbita, donec nihil humidi amplius in fundo appareat; adhibita semper maxima cura et diligentia, ut ignem ita modereris, ne ebulliat usque ad alembici canalem. Nam si hunc ebullitio attigerit, sedare non potes, neque prohibere, quin in receptaculum egrediatur, ac totum oleum perdat; solet enim facilime ebullire. Tum videbis duo contineri in eo, aquam videlicet humorem ac pinguem; segregabis vero unum ab altero statim, ita ut mhil aqueum in oleo relinquatur, nam aqua illa oleum corrumpit; segregatum oleum usui reserva." |