"Still another separating vessel has been devised for this same purpose. The bulging flask contracts to a narrow neck, to the middle of which is attached a bill-like tube. The oil mixed with water is poured into this flask, the water remains below, the oil rises to the surface and into the neck. Water is then added drop by drop so that the pure oil flows drop by drop out of the bill. In the case of other oils which sink to the bottom, the water is allowed to flow out above. Any water remaining at the surface is removed by cotton (a lamp wick) whereby the purest oil remains behind."1)
1) Joh. Baptistae Portae, Neapolitani Mag/as naturalis libri viginti, in quibus scientiarum naturalium divitiae ct deliciae demonstrantur. lam de novo, ab omnibus mendis repurgati, in lucem prodierunt. Romas 1565. Antwerp. 1567. Editio Hanoviae 1619. Liber decimus: Destillat, destillata ad fastigia virium sustollit. p. 367 - 412.
The Florentine flask, like many other improvements pertaining to the art of distillation which were not generally known, was soon forgotten. As a result it was rediscovered several times from the beginning of the 17. century to the year 1823. Thus the flask was again described and introduced by Hom-berg'2) at the end of the 17. century, about one hundred years after Porta's description - only, however, again to be forgotten for a considerable period of time. A century later, in the year 1803, the Florentine flask was again recommended for the distillation of volatile oils by the Augsburg apothecary Johann Gottfried Dingier3) and later in 1823 once more introduced as something new by the apothecary Samuel Peetz4) in Pesth.
The Florentine flask of older construction, as described by Porta, has been in use for a long time. The oil was siphoned off by means of a porous siphon consisting of a lamp wick into small bottles (fig. 40). Later the Florentine flask shown in fig. 41 was also used. The flask used at the present time in the large factories is not only larger, but contains in the upper part on a level with the oily layer a glass stopcock through which the oil can be drawn off from time to time (fig. 43), or an overflow tube through which the oil when it reaches a certain level runs into a receiver (fig. 42).
In the course of time a number of differently constructed receivers for the separation of the volatile oils have been proposed, without however, causing the Florentine flask to be discarded. The first of these was proposed by Amblard of Paris1) in 1825. It consisted of a conical glass tube, open at both ends and drawn out to a taper. This tube was suspended by means of a cork ring at its upper end in a high glass mixing cylinder. This cylinder was provided at the top with an overflow tube. The oil collects in the glass tube and can be removed from this after closing the small lower opening, by pouring out as often as desired. The more salable volatile oils which were used in larger quantities in the perfume industry that had developed in France in the course of the 18. century were still prepared during the first quarter of the 19. century in the traditional primitive distilling vessels, and were improved by rectification. In Germany the apparatus shown in figs. 38 and 39 were principally used. While the oils of lavender, rosemary, orange flower, and other fragrant oils (essences) were manufactured in France, and rose-oil in Turkey, Germany and Hungary supplied the market with the oils of caraway, fennel, anise, coriander, calamus, peppermint, spearmint, valerian, chamomile, and others used in medicine and in the fine arts. In southern France, especially on the sunny slopes of the Alps near the Mediterranean coast, the industry of the aromatic oils developed considerable proportions in the early part of the past century. The oils principally used for medicinal purposes, however, were still prepared in apothecary laboratories. In the course of time certain apothecaries and druggists, having made a beginning on a small scale, erected much larger establishments for the preparation of volatile oils. This was done especially in regions suited to the cultivation of medicinal plants, for instance, in Thuringia on the Saale and the Elbe, in Saxony, Bohemia, Franconia, and also in Hungary. Only a few of these, however, remained in existence for any appreciable length of time. As in other branches of chemical industry, these originally small distilling operations were replaced everywhere by a larger, more rational and efficient industry. Since the middle of the past century this new industry has worked hand in hand with science and technology. It has not only enlarged, but also improved the conventional methods and apparatus for distillation. Whereas on the one hand it utilized the results of science, on the other it not only stimulated science, but gave direct assistance.
1) ". . . . Quomodo oleum ex aquis separemus - aliud separatorium vas ad idem ingenuosissime excogitatum est, tenuet venter vasis, collum angustum est, cujus medio rostellum affixum est. Transfundatur in vas oleum aqua remistum, occupat aqua fundum, oleum supra collum: guttatim aquam addes, donec oleum ascendat ad rostellum, ex pernento, inclinato vase, descendet purissimum oleum et purgatum, ubi aliquid evacuasti, sensim aquam addendo, ascendit oleum ad canaliculam coq.; iterum in-clinato, reliquum transfundas. Si vero oleum subsidet, aqua super adlatur, ut multories eveniet, in latam fideliam vel quodcunq.; vas impositum, gossipino licineo adaptato, aqua foras transmeabit, oleum purissimum quod superest, in fundo residebit".
2) Philippe and Ludwig, Geschichte der Apotheker. 1858. p. 513.
3) Trommsdorffs Journ. der Pharm. 11, II. (1803) 242.
4) Buchner's Repert. fur die Pharm. 14, III. (1823), 481.
1) Bulletin des travaux de la Societe de Pharm. Paris, May 1825, p. 247.
Fig. 42. Receiver for oils lighter than water.
Fig. 43. Receiver for oils heavier than water.