on certain Stony and Metalline Subflances. 2<J 



Portugal Feb. 19, 1796, and was taken, (till warm, from 

 the ground *. 



The firft of thefe peculiar fubftances with which chemiftry 

 has interfered, was the (tone prefented by the abbe Bachelay 

 to the Royal French Academy. It was found on the 13th 

 of Sept. 1768, yet hot, by pcrfons who faw it fall. It U 

 defcribed as follows f : 



" The fubftance of this done is of a pale afti-gray colour ; 

 when examined with a magnifying glafs, it is found to be 

 interfperfed with a multitude of fmall brilliant metallic points 

 of a pale yellow colour; its exterior iurface, that which, ac- 

 cording to the abbe Bachelay, was not engaged in the earth, 

 was covered with a fmall and very thin ftratum of a blackifh 

 matter, puffed up in fome places, and which appeared to have 

 been fufed. This (tone, when the interior of it was ftruck 

 with fteel, produced no fparks : on the other hand, when 

 (truck on the thin external ftratum, which appeared to have 

 been attacked bv fire, fome few fparks were elicited/' 



The fpecific gravity of this ftone was as 3535 to 1000. 



The academicians analyfed the (lone, and found it to contain 

 Sulphur - - 8~ 



Iron 36 



f Verifiable earth - 55I 



100 



Of their mode of analyfls, I (hall have oecafion to fpealt 

 hereafter. They were induced to conclude, that the ftone. 

 prefented to the academy by the abbe Bachelav, did not owe 

 it?, origin to thunder; that it did not fall from heaven ; that 

 it was not formed by mineral fubftances, fufed by lightning; 

 and that it was nothing but a fpecies of pyrites, without pe- 

 culiarity, except as to the hepatic fmell difengao-ed from it by 

 marine acid. " That this ftone, which was, perhaps, covered 

 by a fmall ftratum of earth or turf' may have been (truck 

 with lightning, and thus uncovered: the heat may have 

 been furficiently great to fufe the furface of the part ftruck, 

 but it may not have been long enough continued to be able 

 to penetrate to the infide : on this account, the ftone has not 

 been decompofed. The quantity of metallic matters it con- 

 tains, oppofing lefs refiftance than another body to the cur- 

 rent of the electric matter, may perhaps have contributed to 

 determine the direction of the lightning/' 



The memoir is however concluded, by obferving it to be 



* Letter* wiicten during a fhort Rcfidence in Spain and Portugal, 

 page 239. 



f Here, and in the two following quotations, Mr. Howard gives the 

 original words of the author; we have fubftituted faithful tranflations.— 



fufficieiidy 



