from December 1826 to Av^st 1827. 249 



ment of their discovery, and have no doubt arisen from the ac- 

 tion of the air, which in a few hours had produced such an al- 

 teration in their superficies, as had not been accomplished by 

 the influence of so many centuries. This is a proof that these 

 olives, gathered eighteen centuries before by the subjects of Ti- 

 tus, are as fresh and sweet as those produced by Francis I. 

 Indeed, these ancient olives are still soft and pulpy ; they have 

 a strong rancid smell, a greasy taste, and leave upon the tongue 

 an astringent and sharp sensation. They are so light, that they 

 swim upon water ; the pericardium or seed-vessel shews still its 

 organic texture, though the parenchyma is in that state of alte- 

 ration which the maceration of a few months usually produces. 

 The kernels are still hard, and so much so that a knife can 

 scarcely penetrate them. The oily part of the parenchyma, 

 though in very small quantities, when analysed carefully in the 

 usual method, has been found to be changed entirely into oleic 

 and margaric acids, which are the fundamental principles of the 

 fixed oils, acidified by oxygen, and form the basis of our soaps. 

 These changes happen generally in oils exposed for some time 

 to the air. This proves that the action of eighteen centuries, 

 which has left untouched the fundamental principles of the oil, 

 has effected no greater change than what is produced by a few 

 months. 



The kind of oily substance in which the olives are enveloped, 

 is of a brownish-yellow colour, soft like butter, has a strong 

 rancid smell, soils paper like fixed oils and greasy substances, 

 is melted by a moderate heat (60° or 70° cent.) warmed on a 

 leaf of platina ; it burns with a beautiful white flame, without 

 leaving any thing but small white flaky ashes, so light that the 

 smallest puff disperses them. With the alkalies it forms soap ; 

 distilled in close vessels, it gives out carburetted hydrogen gas, 

 acetic acid, carbonic acid, carbonic acid gas, and a residue of 

 carbon. This buttery substance, tried by CheuvreuPs method, 

 is found to be composed of oleic acid in large quantities, a small 

 portion of margaric acid, and a substance analogous to the sweet 

 principle of fixed oils, but which differs in many respects, and 

 \ihich may be a new production ; and, lastly, an earthy sub- 

 stance, in very small quantities, arising from the volcanic ashes 

 which filled the upper half of the vase. 



