Of the DEVON IRON WORKS. 35 



thing ; particularly, the noife of the air efcaping at the blow- 

 pipe, or wafle valve, was very loud, and feemed to return back 

 to us. There was no appearance of wind to difturb the flame 

 of our candles ; on the contrary, I was furprifed to find, that 

 when we put one of them into the eduction pipe, which con- 

 veys the wind from the vault to the furnaces, it was not blown 

 out. There was not the fmalleft appearance of any drops of 

 water ifluing out of this pipe. The ouzing and dropping of 

 water from the fide of the rock, next the bank, feemed the fame 

 as before the condenfation was made in the vault. In {hort, 

 every thing appeared, in other refpects, the fame as when we 

 were in the common atmofphere. Having remained about an 

 hour in the condenfed air, and fatisfied ourfelves that no water, 

 during that time, that we could in the leaft difcover, was agita- 

 ted and forced out of the rock and vault by the power of the 

 blafl, as was imagined and infilled on, we gave the fignal to flop 

 the engine. As foon as it ceafed to work, and the condenfation 

 abated, and before the door of the vault was unfcrewed, the 

 whole vault, in a few feconds, became filled with a thick vapour t 

 fo that we could hardly fee the candles at four or five yards di- 

 Jlance. The door being now opened, the work people, anxious 

 to know our fituation, and what had occurred, came into the 

 vault, and prevented any further obfervations. 



I now endeavoured to account for this curious appearance of 

 the water, which only fhewed itfelf occasionally, in very finall 

 quantities, at the tweer, and at a hole 1 ordered to be made in 

 the bottom of the wind chefl to collect it more accurately, for 

 it never was obferved, but either when the engine, after work- 

 ing flowly, was made to work quicker, or, after having been 

 flopped for a few minutes, was fet to work again. 



I considered the vapour which we had difcovered in the 

 vault to arife from the moiflure of the fide of the rock next the 

 furnace, which being expelled by the great heat of the furnace, 



E 2 and 



