Subterj-aneous Cd"Jern at Paris. 583 



But Mr. Smeathman informed me, that when 

 he defcended the laft winter, in the long and 

 hard froft, he found the air much more tempe- 

 rate than above ground, but far from warm. 

 Neither, however, had he a thermometer with 

 him. I lamented too that I had not time to 

 make more remarks on the petrefaflions, &c. 



Mr. Smeathman obferved, that when he de- 

 fcended, he found a very fenfible difficulty of 

 breathing in fome of the pafiages and caverns, 

 where the fuperincumbent rock was low, and 

 the company crowded. This no doubt was 

 much increafed by the number of perfons and 

 of wax lights, but he does not apprehend that 

 the difficulty would have been fo great in rooms 

 of equal dimenfions above ground. We re- 

 marked too, when we delcended, that there 

 was, in fome degree, an oppreffion of refpiration 

 throughout the whole paflage. 



There were formerly feveral openings into 

 the quarries, but the two I have mentioned, 

 viz. the Objervatory and the Val de Grace, are, 

 I believe, the only ones left ; and thefe the in- 

 fpeftors keep conftantly locked, and rarely open 

 them, except to ftrangers particularly introduced, 

 and to workmen who are always employed in 

 fome part by the King. 



The Police thought it a neceffary precaution 

 to fecure all the entrances into this cavern, from 

 its having been formerly inhabited by a famous 



rang 



