378 ^^'* ^' ^'&^V.?V Account of the 



Claude PerrauU, Member of the Academy of 

 vSciences, and firft architeft to his majefty. It 

 ferves for the refidence of mathematicians, ap- 

 pointed by the king, to make obfervations, and 

 improve aftronomy. The mode of building it 

 is ingenious, and admirably contrived, it being 

 fo well arched that neither wood nor iron are 

 employed in its conftru6tion. All the ftones 

 have been well chofen, and placed with an uni- 

 formity and equality which contribute much to 

 the beauty and folidity of the whole edifice. It 

 is reckoned to be about eighty or ninety feet in 

 height, and at the top there is a beautiful platform, 

 paved w/ith flint ftones, which commands an ex- 

 cellent view of Paris, and its environs. In the 

 different floors of this building, there are a num- 

 ber of trap-doors, placed perpendicularly over 

 each other, and, when thefe are opened, the ftars 

 may be very clearly dillinguiflied, from the bot- 

 tom of the cave, at noon day. 



At this place, I was introduced to one of the 

 infpe6tors, (perfons appointed by the king to 

 fuperintend the workmen) by my friend Mr. 

 Smeathman, who had ufed great application and 

 intereft for permiflion to infped the quarry, and 

 had been fortunate enough to obtain it. For 

 as this cavern is extended under a great part 

 of the city of Paris, and leaves it in fome places 

 almofi: entirely without fupport, the infpeftors 

 are very particular as to fhewing it, and en* 



deavour 



