NOTIiS OX THK ESSENTIAL OILS. 

 IXLLLDIXC; AX ACCOUNT OF THE xMATl-RIALS 



AXi) Mirnions nv pi-rflmi:k\'. 



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II. 1-'. SL.VCK. riianiiacist. 



Thi; subject matter embraced by tlie above title 

 covers one of the most extensive fields of modern 

 industrial organic chemistry, and therefore it has 

 not been attempted in this article to give more than 

 a rudimentary outline of the numerous branches and 

 processes involved, each of which is individuallv of 

 sufficient importance and magnitude to merit the 

 dedication of an entire volume. 



It has been endeavoured, however, to give a brief 

 resume of the modes of preparation ; the composition, 

 and examination of the volatile oils ; to name and 

 describe certain animal and artificial substances 

 employed in the manufacture of perfumes, and to 

 conclude with a short survey of the methods adopted 

 in manipulating to the best advantage numerous 

 natural and synthetic products used for producing 

 the exquisite and subtle combinations of odours 

 possessed by many of our modern spirituous 

 essences. 



Bearing in mind that the spices and aromatics 

 have been from time immemorial, and are at present, 

 a prominent factor in the world's commerce, it mav 

 not seem out of place to commence with a brief 

 retrospect of the history of the essential oils, which 

 may be, for practical purposes, broadly defined as 

 oily, odoriferous bodies, volatile without decomposi- 

 tion, obtained from vegetable sources. 



In this, as in most researches into ancient historic 

 documents, investigation as to the source and dis- 

 tribution of these materials leads to Central .\sia, 

 where the spices found use not onlj- on account of 

 their agreeable odour and taste, but also as articles of 

 exchange, and in religious and sacrificial ceremonies. 



Whether a beginning of the preparation of the 

 aromatic principles of plants, our modern volatile 

 oils, was made previous to early Hindoo or Eg\ptian 

 civilization, does not become apparent, even from 

 the oldest documents ; but we know that the 

 Egyptians, whose history dates back as far as 

 4000 B.C., were acquainted with common metals, 

 furnaces and distilling apparatus. 



The study of natural sciences was carried on to 

 some extent by the Greeks and Romans, the insight 

 gained by the latter people into the character of 

 drugs being demonstrated by the writings of 

 Dioscorides, Pliny and Galen. A decided advance 

 in scientific research was achieved by the .Arabs, who 

 fostered the process of distillation already described 

 by Synesios and Zosimos, two Greek scholars of the 

 fourth century. The decay of Arabian science was 

 brought about, however, by their ardent desire to 

 convert the baser metals into gold, and it was not 

 until the advent of Paracelsus, who taught that the 



object of chemistry was to make remedies and not 

 gold, that a marked development of the art of 

 distillation and a clearer conception of the nature 

 and composition of the essential oils were acquired. 



Information as to the subsequent progress of the 

 oil-distilling industry is available in the form of 

 several lists of current drugs and spices in the cit}- 

 of Frankfort-on-the-Main, which were published 

 during the years 1450, 1580 and 1587, and in a book 

 entitled the " Destillirbuch,"" written by Brunschwig 

 and published during the sixteenth century. 



Although in the year 1730 about one hundred and 

 twent)' volatile oils were known and placed in general 

 use and commerce, it was during the eighteenth 

 century that a great stimulus to the art of perfumery 

 was initiated by the successful combination of several 

 odours in attempts to produce agreeably fragrant 

 mixtures. An example of such a preparation is 

 afforded b\- the Eau-de-Cologne of Johann Maria 

 Farina, introduced in the year 1725. which, in its 

 modified form, is in great demand at the present 

 time. The consequent greatly increased production 

 of the oils, and constant growth of the industry in 

 the South of France, caused more attention to be 

 devoted to the constitution of the valuable primary 

 odoriferous bodies which are applied in the per- 

 fumery art. Classical researches in this direction 

 wtre conducted in Germanv and France, but, as a 

 record of these would be of a purelv chemical nature, 

 \\c w ill apply ourselves to a study of the isolation of 

 the volatile oils, and incidentally, by the aid of a 

 few diagrams, endeavour to trace the evolution of 

 the modern steam distillation apparatus from the 

 almost inconceivable crudities tolerated in the appli- 

 ances used b)- the ancients and during the Middle .Ages. 

 The primitive distillation vessels employed in the 

 production of the essential oils are described as open 

 kettles heated by a direct fire, and having, as a con- 

 denser, a layer of wool supported bv pieces of wood 

 placed across the opening (Figure 478). 



The form of subsequent stills appears to have been 

 based upon the outline of certain animals; for 

 instance, the goose provided an idea for a retort, as 

 illustrated by Figure 479. 



A further step was then taken bv employing the 

 advantages of the water and sand baths to replace 

 the discovered deficiencies of the naked fire previously 

 used, and by adopting various methods of condensing, 

 — by means of air and water — the vapours evolved 

 during the distillation. 



An inefficient type of air condenser, used as 

 early as the fifteenth century and known as the 

 " Rosenhut," is depicted in Figure 480. 



