NATURAL AND ARTIFICIAL PERFUMES. 91 



able importance; and it is not the absolute cost but the probable 

 profit that most deserves consideration. A primary characteristic 

 of perfumes is their immense strength; a very minute quantity of 

 one is sufficient to produce a large effect. Consequently, they may 

 bear a large price without limiting consumption. But, to isolate 

 this as yet unknown perfume, it was necessary to treat enormous 

 quantities of iris powder, and this required industrial resources 

 which the inventors could not command. These were secured by 

 making suitable arrangements with two large houses which became 

 parties in interest. The experiments lasted ten years. First, irone, 

 the principle to which the odor of the violet is due, was isolated. A 

 complete chemical study of it was made. Having remarked that 

 citral, an aldehyde abundantly diffused in Nature, gave, on con- 

 densation with acetone, an acetone of the same crude formula as 

 irone, these authors effected this condensation under the influence 

 of hydrate of baryta. They thus obtained, as they had expected, 

 an acetone of the same crude formula as irone false irone; this, it 

 is true, had neither the odor nor the properties of irone, but by the 

 action of dilute sulphuric acid it was transformed into its cyclic 

 isomer, ionone. From the chemical point of view, ionone not being 

 identical with irone, but only an isomer, the problem could not be 

 said to be solved; but it was fully solved from the industrial point 

 of view. Ionone possesses, like irone, the perfume of the violet, 

 with a slight shade perceptible to practiced noses, but lending itself 

 admirably to all the uses of perfumery. "We have in this a complete 

 example of methodical synthesis, although it must be admitted that 

 the authors were aided by happy combinations of circumstances that 

 might not always occur. 



There are also chance syntheses. Thus, a substance, the odor 

 of which may be utilized, is sometimes fallen upon in pursuing re- 

 searches undertaken for another purpose. This is what happened, 

 for example, in the case of Baur's artificial musk. M. Baur had 

 undertaken the study of two carbides of hydrogen two butyltol- 

 uenes contained in the essence of resin. He isolated and separated 

 these substances, and then in experiments connected with the per- 

 formance of the synthesis he perceived an extremely pronounced 

 odor of musk appertaining to the trinitrile derivative of isobutyl- 

 toluene. M. Baur was not led to his researches by chance, but the 

 discovery of his musk, the most precious result of them, was not 

 anticipated by him. 



There are other cases in which a series of bodies are prepared 

 with full expectation of what the chemical results will be, but with- 

 out knowing what odor they will have, or whether they will 

 be odoriferous, but with the expectation that they will be, and 



