Mac Culloch on Animals preserved in Amber. 47 



The chemical connexion between amber and the existing resins, 

 must also be proved, if that be thought necessary for strengthening 

 this view, by such analogies as can be brought to bear on it, since 

 it is not matter for direct experiment. 



In analyzing chemically the vegetable resins which most resemble 

 amber in their general cbaracters, and in comparing these results 

 with those obtained from the analysis of amber, certain important 

 differences are observed. To enter into the whole of these would 

 exceed the bounds I have here prescribed for this paper. It is 

 sufficient to say, that the essential, or volatile, oils, obtained from 

 all the resinous substances, possess a general resemblance to that 

 obtained from common rosin, or, to the oil of turpentine ; and that 

 they exhibit the same chemical qualities, as these relate, in parti- 

 cular very conspicuously, to their habitudes with alcohol and 

 ether, and, especially, with naphtha, and to the action which they 

 exert on the solid resins and on the solid bitumens. 



The same general powers and properties are found in those 

 essential oils which are produced by the decomposition of recent 

 vegetables and the recombination of some of their elements : and 

 thus a general character is found to pervade all those volatile oils 

 which are the produce of recent vegetable matter under whatever 

 form. But, in analyzing in the same manner, and reproducing 

 volatile oils from vegetable remains, which have been so long and 

 so deeply buried in certain alluvial soils as to lead us to suppose 

 that they have belonged to a pre-existent state of the surface of 

 the earth, it is found that these are essentially different. The vo- 

 latile oils thus produced, approach in their chemical affinities to- 

 wards those which are obtained from coal ; or from a substance, of 

 which the vegetable origin is rather generally admitted than 

 demonstrably proved. They are all varieties of naphtha, under 

 modifications which, having fully explained them in other writings, 

 it is not necessary here to detail again. 



Now the same analogy holds in comparing the produce of the 

 vegetable resins with that of amber, as occurs in comparing the 

 oil of recent wood with that of jet, and more particularly with that 

 of coal. It is here unnecessary to enter into the minute differences 



