34 PHENOMENA obferved in the AIR VAULT 



now difcovered that water was, in confiderable quantities, driven 

 out of the air vault through the blow-pipe, which cooled the fur- 

 nace; and they infifted, that the power of the engine was fuch 

 as to force water out of the folid rock ; fo that this method 

 of equalizing the blaft never would fucceed. The other mana- 

 ging partner was fo much alarmed by thefe reprefentations, 

 that he began to confult with the engineer, and others, about 

 finding a fubftitute for the air vault at any expence. 



As the plan of the blowing apparatus had been adopted at 

 my recommendation, and was now fo loudly condemned on ac- 

 count of the water, I had other motives, than mere interefl, for 

 trying to become better acquainted with the phenomena attend- 

 ing it. I accordingly determined to go into the air vault, and 

 to remain inclofed in the condenfed air while the engine was 

 blowing the furnace. It is an experiment that perhaps never 

 was made before, as there never exifted fuch an opportunity. I 

 could not perfuade the engineer, or any other of the operative 

 people about the work, to be my companions, as they imagined 

 that there was much danger in the experiment. Mr Neil 

 Ryrie, however, one of the clerks of the Devon Company, had 

 fufficient confidence in my reprefentations to venture himfelf 

 along with me. 



The machine had been flopped about two hours previous to 

 our entering the vault, and we found a dampnefs and miftinefs 

 in it, which difappeared foon after the door was fhut fafl upon 

 us, and the engine began to work in its ufual manner. After 

 four or five ftrokes of the engine, we both experienced a fingular 

 fenfation in our ears, as if they were (lopped by the fingers, 

 which continued as long as we remained in the condenfed air. 

 Our breathing was not in the lead affecled. I had no ther- 

 mometer with me, but the temperature of the air felt to us the 

 fame as that without the vault. Sound was much magnified, 

 as we perceived, when we talked to each other^ or ftruck any 



thing ',. 



