rOL. XLIX.J PHILOSOPHICAL TRANSACTIONS. 15 



than the ruins of sea-shells, and limestone consists of the same bodies cemented 

 together by a stony juice. Amber appears evidently to be the resin of antedilu- 

 vian trees (which are frequently found along with it at this day) united to the 

 acid of sea-salt, which abounds in the earth. The reason of insects, straws, 

 &c. being immersed in amber, absolutely inexplicable from the hypothesis of its 

 being of mineral origin, is now no more a secret; for we know that nothing is 

 more common, than to find such bodies immersed in the resin of trees. 

 Fossil sea-salt, or salt-gem, seems to have been deposited in the quarries, whence 

 it is dug, at the time of the deluge. All or most part of pit-coal appears to be 

 of diluvian origin, for it gives a caput mortuum, the texture of which exactly 

 resembles that of burnt wood. We may reasonably suppose large forests to have 

 been buried at the time of the deluge, which have undergone a fermentation 

 and putrefaction in the earth, so that the colour of the woody part has been 

 changed, though the texture has remained entire enough to allow us to dis- 

 tinguish to what kingdom it belongs. All bitumens, pissasphaltum, pessilaeum, 

 &c. seem to be no more than productions of resinous substances united with mi- 

 neral acids, which have caught fire in the earth by fermenting with heteroge- 

 neous matter, and have thus undergone a sort of natural distillation and exalta- 

 tion. These are more than chimerical notions, and are even demonstrated by 

 experiments ; for amber can be produced artificially, as also bitumens by the 

 distillation of resinous substances with mineral acids ; and there is great proba- 

 bility that pit-coal might be imitated. 



CVL A Retractation, by Mr, Benjamin TVilson,* F.R. S. of his former Opinion, 

 concerning the Explication of the Ley den Experiment, p. 682. 



I think it necessary to retract an opinion concerning the explication of the 

 Leyden experiment, which I troubled this Society with in the year 1746,-}- and 

 afterwards published more at large in a Treatise on Electricity, in the year 1750; 

 as I have lately made some further discoveries relative to that experiment, and the 

 minus electricity of Mr. Franklin, which show I was then mistaken in my notions 

 about it. What I mean by the minus electricity of Mr. Franklin regards the 



* Mr. Wilson died June 6, 1788, at the age of 80 or upwards. It is said he had been formerly 

 an eminent painter. For many years before his death he enjoyed the lucrative contract for the 

 house, &c. painting under the Board of Ordnance. He wrote a Treatise on Electricity, published in 

 1750, and some papers on the same subject in several volumes of the Phil. Trans. But he has been 

 chiefly distinguished as the ostensible person whose perverse conduct in the affair of the conductors 

 of lightning produced such shameful discord and dissensions in the Royal Society, as continued for 

 many years after, to the great detriment of science. 



f That paper was not published in the Phil, Trans. 



